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CAPA SCIENTIFIC JOURNAL

ISSN 2310 - 6298

DECEMBER 2014 • VOL. 2 • NUMBER 1

scientific journal edition 2.indd 1 04/12/2014 15:05

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CAPA SCIENTIFIC JOURNAL • ISSN 2310 - 6298

Editorial Board

Editor-in-Chief

Prof. Josphat K. Z. Mwatelah Vice Chancellor, Technical University of Mombasa, P.O. Box 90420-80100, Telephone: +254 041 2492222/3/4, Email: [email protected], Mombasa, Kenya

Deputy Editor-in-Chief

Rev. Prof. Daniel A. Nyarko Rector, Takoradi Polytechnic, Post Office Box 256, Takoradi, Ghana, Telephone: +233 312 22917/8. Email: [email protected] Ghana

Editor

Dr. Titus Tunje Kadere Registrar (AA), Technical University of Mombasa, P.O. Box 90420 – 80100, Telephone: +254 041 2492222/3/4 Email: [email protected], [email protected], Mombasa .Kenya

Assistant Editor

Mr. Johannes Kioko Muoka Dean of Student Affairs, Mombasa Technical Training Institute, P.O. Box 81220 – 80100, Telephone +254722464817, +254735482679, Email: [email protected] [email protected], Mombasa, Kenya.

Other Editors

Dr. Richard Masika Principal, Arusha Technical College P.O. Box 296, Tel: +255 27 2503040, Fax: +255 27 2548337, Mob: +255 27 2502075 E-mail: [email protected], Arusha,Tanzania

Dr. M. A. Kazaure Executive Secretary, National Board for Technical Education, P.M.B 2239, Plot “B” Bida Road, Kaduna, Nigeria, Tel/Fax: +234 062 247507, Phone: +234 062 246554, Nigeria

Mr. Samuel Moyo, Principal, Luanshya Technical and Business College, Email: [email protected], Zambia

Dr. Rafael Massinga Director General, Instituto Superior Polytechnico de Manica, Telephone: 21 361 63 40, Email: [email protected] Maputo, Mozambique

Dina Amankwah Accra Polytechnic Research & Innovation Department, P. O. Box GP 561, Tel: +233 302 689276, 233 302 689279 Email: [email protected], Accra - Ghana


mailto:[email protected]









mailto:%[email protected]


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CAPA SCIENTIFIC JOURNAL

FOREwORd

The maiden issue of the CAPA Scientific Journal (CAPA sci.j.) was launched in November, 2013 by His Excellency, Dr. Mohammed Gharib Bilal, the Vice President of the United Republic of Tanzania at the opening of the 24th international conference of the Commonwealth Association of Polytechnics in Africa, held at the Arusha International Conference Centre, Tanzania. The CAPA sci.j. is a multidisciplinary scientific journal that provides vital information on research, development and innovations in engineering, science, technology and business related fields, particularly from technologically-oriented institutions – technical universities, polytechnics and other TVET institutions.The publication of this second issue demonstrates the highly commendable commitment of the Editorial Board to the fulfillment of one of CAPA’s core mandate, which is to provide a dynamic forum for gathering, testing and sharing of innovative ideas in technical and vocational education and training. It is also an encouraging outcome of the increasing awareness of the critical importance of applied research and academic publications among stakeholders in CAPA member institutions. The Executive Board of CAPA deserves appreciation for initiating the establishment of the CAPA Scientific Journal; while the Chairman / Editor-in-Chief, Prof. J.K.Z. Mwatelah and other members of the Editorial Board have done extremely well to actualize the initiative. In particular, the editor of the journal, Dr. Titus Tunje Kadere, assisted by Mr. Kioko Muoka, have worked tireless and diligently to ensure that CAPA sci.j. secured international accreditation and recognition. It is our hope that this and other issues of CAPA sci.j. will be useful as a resource material for knowledge and information on the state of the art and trends in the fields of engineering, S&T and related fields; and that the journal would inspire innovative works that could find applications in technological and industrial development to boost the economies of member countries.

Dr. Olubunmi Owoso; NPOMCAPA Secretary GeneralDecember 2014


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TABLE OF CONTENTS

CAPA Scientific Journal .......................................................................................................................................... 4

Foreword ...................................................................................................................................................................4

Innovative Drip Emission Devices for Resource-Poor Farmers under a Changing Climate ...................... 6

Isolation and Identification of Yeasts in Mnazi ................................................................................................14

Local Manufacturing of Wind Turbine, a Solution to Harnessing Abundantly Available Wind Energy in Africa (Case Study: Tanzania) ..............................................................................................................................27

Design of Cost Effective Isolated Mini-Grid for Rural Electrification (Case Study: Simike Mini-Hydropower Project in Mbeya, Tanzania)..........................................................................................................35

Diurnal diversity and activity density of Bees on Frenchbean (Phaseolus vulgaris L.) Flowers in Meru County, Kenya ........................................................................................................................................................40

Competence Profiling for Loans Officers in the Banking Sector in Sub-Saharan Africa: A Case of Uganda .....................................................................................................................................................................45


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Introduction

Water scarcity is arguably the single greatest threat to global food production (Postel, 1999). According to the United Nations Environment Program (UNEP, 2002), about one-third of the world’s population lives in countries or regions where there is insufficient water to meet modest per capita food and material needs. With looming impacts of climate change, more people are expected to be under water-stressed conditions in the near future. This will undoubtedly impact agricultural production.

Climatic variability on the seasonal-to-interannual time scale affects many facets of human life including food security and livelihoods. The climate of the semi-arid tropics is a primary constraint to agricultural development

(Kanemasu et al., 1990). Changes in the length of growing season can result from changes in rainfall patterns due to climate change (Kihupi et al., 2007). So pervasive are the implications of climatic variability for human welfare (Stern and Easterling, 1999), that a wide variety of measures have been suggested for adaptation including water conservation (Boland, 1997) and changes to agricultural practices (Adams, 1990).

Increasing agricultural productivity and income of the majority of farmers in developing countries, including Tanzania where most cultivate less than one hectare of land, is a relatively untapped opportunity for finding practical solutions to rural poverty. It has been noted that water productivity needs to be doubled in order to meet the water requirements of future generations (Postel, 1999). This will require making irrigation

INNOvATIvE dRIP EmISSION dEvICES FOR RESOURCE-POOR FARmERS UNdER A ChANgINg CLImATE

1Kihupi, N.I., 1Tarimo, A.K.P.R., 2Masika, R.J., 3Pyuza, A.G., 1Samwel, S., 4Boman, B., and 5Dick, W.A.1Sokoine University of Agriculture

2Arusha Technical College3Kilimanjaro Agricultural Training Centre

4University of Florida5Ohio State University

Abstract

Agriculture is the world’s largest user of water resource hence contributes to the dwindling fresh water resources that threaten global food production. Micro-irrigation technologies are increasingly being used in addressing the growing competition for scarce water resources. However, these technologies are not readily accessed by most small-scale subsistence farmers who comprise more than 90 percent of the farming population in Tanzania. The major constraint for adoption of micro-irrigation is the initial cost of purchasing and installing the technology. The water savings of a properly designed and operated micro-irrigation technology can help conserve the meagre water resources available for agricultural production and increase crop yields and quality. This study aimed at developing an on-line emission device for a low-cost drip irrigation technology that was robust, cheap, and hydraulically efficient for use on locally available tubing material. Two such emission devices coined as “cast-head” and “screw-head” were developed and hydraulically tested in the laboratory for their performance. Both emission devices had emitter exponents indicative of non-pressure compensating type with a turbulent flow regime. The flow rate for the “cast-head” emission device varied from 1.15 to 3.16 l/h while that for the “screw-head” type varied from 0.69 to 1.82 l/h at pressure heads of 0.5 to 2.5 m respectively. The performance of the “screw-head” emission device was far superior to that of the “cast-head” type. Such an emission device has all the qualities that match smallholders’ unique characteristics. It is therefore recommended that further tests be done on this emission device to establish optimal design parameters that will result in minimum initial investment cost.

Key words: Irrigation, climate change, emission, technology, screw-head, cast-head


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more effective and promoting technologies that enable farmers to get more crops per drop. It will also require redressing flaws of the modern irrigation age, particularly the failure to provide technologies and methods that allow the smallest and poorest farmers to benefit from improved irrigation.

Drip irrigation system is ideal in terms of achieving high irrigation uniformity and minimizing water use with enhanced productivity. Most conventional drip irrigation systems use commercially manufactured components, which to a large extent are beyond the reach of the majority of rural farmers in the developing world. Technological developments have led to innovative designs aimed at reducing the problem of emitter clogging (Ali, 2013), which is one of the major disadvantages of the system. Considerable work has also been done to simplify the emission device so as to satisfy the requirements of small-scale farmers in less developed countries (Awe and Ogedengbe, 2011; Umara et al., 2012). Low-cost drip irrigation systems can fill an important technology gap for the rural poor by providing a low-cost entry into irrigated agriculture. Smallholders are able to benefit from drip systems because they can be adapted to small and varied plots of land. Low-cost drip irrigation systems retain the benefits of conventional drip systems while removing the factors that prevent their uptake by poor farmers. In many parts of the developing world, smallholders, mostly women, struggle to maintain backyard gardens using hand-watering to cultivate vegetables.Women farmers are responsible for more than 50 percent of global food production. In developing countries, women produce between 60 and 80 percent of the food. Studies done in Asia (Upadhyay, 2004) suggest that there is substantial saving of time in drip irrigated plots (as much as 58 percent) and that the overall workload of women and children has also significantly been reduced due to fewer weeds on the farm under drip system. There have also been notable improvements in income generation from use of low-cost drip irrigation systems by women. This has increased their bargaining power in both household and the community.Micro-irrigation systems are increasingly seen as a means of addressing the growing competition for scarce water resources. Appropriate low-cost drip systems have had positive effects on yield, incomes and food security. With the right institutional support, these systems can help poor farmers improve water productivity and incomes

(IWMI, 2006; Ella et al., 2009). Chapin Watermatics, International Development Enterprises (IDE), Netafim, and some other actors have made pioneering efforts. However, some of these efforts to develop and promote affordable small-scale irrigation systems (ASITs) have failed as commercially sustainable enterprises (Keller et al., 2005). The problem with such kits for smallholders is that they are rather costly. Further, emitter configuration (integral or in-line) makes it difficult to maintain them under the conditions pertaining in rural areas in most developing countries. Most commercial drip irrigation systems have embedded or in-line emitters which are difficult to maintain and require water that has undergone considerable filtration. Such emitters invariably add to the cost of the entire system, which most resource poor farmers cannot afford. It was thus argued that if such system component is made using locally available materials, the cost of a drip irrigation system could become affordable by many small-scale farmers in rural communities.In sub-Saharan Africa, Tanzania in particular, there are many constraints on the spread and adoption of low-cost drip irrigation including lack of awareness, availability of affordable kits, and promotion of costly state-of-the-art micro-irrigation systems by local and foreign firms. It is against this background that this study set out to develop an affordable and appropriate drip emission device. This device can be used on any locally available tubing material with the contention that it is not sufficient to merely scale-down state-of-the-art irrigation technologies that are appropriate for larger commercial farms; rather systems must be re-engineered to match smallholders’ unique characteristics.

Materials and Methods

Two types of devices were developed. The first type, coined as cast-head emission device, involved use of a microtube (4 mm and 6 mm internal and external diameter respectively) that was connected to a short length of PE tubing with a cement-sand cast (Fig. 2a). The emitter head was constructed by casting one end of the microtube (20 mm in length) in a cement-sand mixture within a short length (50 mm) of a ½-inch PE tubing. A hole was created using a thin wire with a diameter of 1.0 mm that was embedded centrally during casting so as to connect with the microtube within the cast from the opposite end. This way, different flow rates could be obtained by varying either the diameter or length of the hole within the cast head or both. Casting was done using cement and sand at a


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ratio of 1:3. After 2 to 3 hours of curing the wire was carefully pulled out thereby leaving a hole of the same diameter. Curing of the cast head took 3-4 days. A schematic representation of a typical emission device is as shown in Figure 1 below:

Figure 1: Schematic representation of an emission device

The second type of emission device, coined as screw-head emission device, was of a much simpler and probably cheaper design. The same micrrotube with an internal diameter of 4.0 mm and wall thickness of 2.0 mm was used but without the cast head. Instead, a screw with a diameter of about 4.0 mm was used to reduce the flow rate by screwing it into the outlet end of the microtube so as to create the long flow path needed to dissipate energy (Fig. 2b). A number of screw types varying in length and structure were tested to find a suitable one. The microtube length was also varied to provide a wider choice of the preferred combination. For a given screw type, the discharge was adjusted by varying the length ∆L (Fig 2b) of the screw.

Figure 2: Schematic representation of emission devices: (a) cast head type (b) screw head type Performance evaluation of the emission devices was done through a laboratory setup comprising of a header tank supplying water to the drip laterals at a constant head. The tank inlet was fitted with a ball valve to maintain a constant head (Fig. 3). A supply pipe conveyed water from the tank to the manifold

(¾-inch PE pipe) from which 5 lateral lines (½-inch PE pipe) spaced 1 m apart, were connected using tee connectors. The two ends of the manifold were plugged. Ten emission devices were connected on each lateral giving a total of 50 emitters as per ASABE standards (ASABE, 2010).


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Connection of individual emitters was facilitated by slightly warming the free end of the microtube to make it softer for easy insertion and in order to provide a snug fit after the tube has cooled. This resulted in a watertight joint with no leakages. The emitter spacing was kept at 25 cm, the spacing common for some vegetable crops. This resulted in lateral length of 2.5 m which is short enough to maintain the desired constant pressure. All lateral lines were plugged at the end.

Measurements of emitter flow rates were taken using 10-litre plastic containers placed under each emitter after the system had been run for a few minutes in order to even out pressure within the laterals (Kirnak et al., 2004). Tests were carried out at five different pressure heads (0.5, 1.0, 1.5, 2.0 and 2.5 m). Duration of the actual measurements was one hour, after which water in the containers was measured volumetrically using a graduated 1,000 ml measuring cylinder. The following system performance parameters were determined:

(i) Emitter flow variation (qvar)

qvar is expressed as (Keller and Karmeli, 1974):

100max

minmaxvar

=

qqqq (1)

where:

qmax = maximum emitter flow rate (l/h)

qmin = minimum emitter flow rate (l/h)

(ii) Uniformity coefficient (Cu) of emitters

Cu is expressed as (Merriam et al., 1980):

÷÷

=

mnx

Cu 1100 (2)

where:

m = average value of all observations

n = total number of observations points

x = numerical deviation of all observation points from the average application rate

(iii) Emission uniformity (EU)

EU is expressed as (Keller and Karmeli, 1975):

[ ]()avgv qqCnEU min5.027.11100 =

(3)

where:

Cv = manufacturer’s coefficient of variation

n = number of emitters per plant

qmin = minimum emitter discharge rate

qavg = mean emitter discharge rate

(iv) Manufacturer’s coefficient of variation (Cv)

Cv expresses the unit to unit variation in the flow (Vermeiren and Jobling, 1984):

avgqv qsC = (4)

where:

sq = the standard deviation of discharges of emitters tested at a reference head (generally corresponding to nominal flow rate)

qavg = the mean discharge of emitters tested at a reference head

(v) Distribution uniformity (DU)

DU is defined by Equation 5 (Merriam et al., 1980):

100÷÷

=

av

LQ

QQ

DU (5)

where:

QLQ = the average of the lowest quarter of the emitter discharge collected

Qav = the average discharge collected

(vi) Head-discharge relationship

The pressure-discharge relationship was determined for various pressure heads ranging from 0.5 to 2.5 m using mean values of flow rate for the respective heads. The emitter flow rate was expressed as a function of pressure by the emitter flow function (Wu and Gitlin, 1977):

xHkq = (6)

where:

q = emitter flow rate (l/h)

k = discharge coefficient

H = operating pressure head (m)

x = emitter discharge exponent

The coefficients k and x were determined by plotting q versus H on a log-log scale from which the slope of the straight line gives x and the intercept at H = 1 is k.


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Figure 3: Setup of a low-cost drip irrigation system for performance testing

Results and Discussion

Tables 1-5 present measured volumes of water in liters collected in each of the catch cans in one hour at five different pressure heads for the cast-head emission device. From the results, flow rate appears to increase with pressure, which is characteristic of non-pressure compensating emitters. Other researchers have reported a similar trend for non-pressure compensating emitters of commercially manufactured products (Hezarjaribi et al., 2008). The calculated x and k values for the emitter flow function were 0.612 and 1.662, respectively, as obtained from a log-log plot of discharge against pressure head (Fig. 4). This emitter can therefore be classified as non-pressure compensating with a turbulent flow regime (Bralts et al., 1981).

Earlier, common plastic drinking straws (Umara et al., 2012) had been tried in place of the microtube, however appraisal of the emission device revealed a potential problem of using straws as a conduit in that they are not robust enough to withstand the rigors of handling under field conditions. There were also problems maintaining a good seal on the connection to the lateral pipe. The microtube selected for this study is locally available and reasonably priced. With a 2-mm wall thickness it was deemed robust enough for the intended purpose. Initial tests for this type of emission device gave rather high flow rates. An office pin was therefore used to minimize the flow rate by slightly twisting it (to make a snug fit) and inserting it into the hole through the cast head. This significantly reduced the flow rate.

There were variations in performance parameters for the different pressure heads as shown in Table 6. The uniformity coefficient (Cu) and distribution uniformity (DU) had values of over 90 percent for the entire range of pressure heads tested. This would seem to indicate that the emitters were of good quality and that the respective parameters are not very sensitive to pressure variations. Similar results, albeit with slightly lower values for Cu under various operating pressures of some on-line, non-pressure compensating emitters, have been reported by Sharma (2013). On the other hand, there were considerable variations with pressure for the rest of the parameters.

Table 1: Flow rate of each emitter (l/h)

at H = 0.5 m for laterals L1-L5

S/N L1 L2 L3 L4 L5

1 1.70 1.50 1.65 1.57 1.44

2 1.54 1.45 1.50 1.50 1.50

3 1.60 1.40 1.65 1.59 1.70

4 1.50 1.45 1.70 1.54 1.50

5 1.45 1.40 1.50 1.49 1.60

6 1.75 1.37 1.60 1.56 1.50

7 1.70 1.40 1.40 1.53 1.60

8 1.60 1.40 1.72 1.54 1.60

9 1.50 1.40 1.55 1.54 1.70

10 1.50 1.40 1.50 1.53 1.73



S/N L1 L2 L3 L4 L5

1 1.20 1.11 1.06 1.15 1.12

2 1.20 1.10 1.10 1.16 1.13

3 1.30 1.12 1.20 1.10 1.18

4 1.10 1.05 1.08 1.12 1.09

5 1.27 1.08 1.16 1.20 1.18

6 1.21 1.20 1.10 1.10 1.15

7 1.25 1.12 1.14 1.20 1.18

8 1.20 1.10 1.10 1.14 1.14

9 1.20 1.13 1.07 1.12 1.13

10 1.20 1.10 1.12 1.20 1.16


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S/N L1 L2 L3 L4 L5

1 2.25 2.00 2.50 2.50 2.31

2 2.64 2.41 2.72 2.50 2.57

3 2.70 2.50 2.30 2.40 2.38

4 2.60 2.40 2.40 2.60 2.50

5 2.50 2.43 2.85 2.30 2.52

6 2.70 2.60 2.50 2.25 2.41

7 2.45 2.50 2.50 2.00 2.36

8 2.65 2.00 2.50 2.40 2.20

9 2.60 2.50 2.00 2.50 2.40

10 2.70 2.75 2.41 2.40 2.57

Table4: Flow rate of each emitter (l/h)


S/N L1 L2 L3 L4 L5

1 2.00 2.14 2.30 2.10 2.14

2 1.90 2.10 2.15 1.90 2.00

3 2.16 1.87 2.30 2.00 2.08

4 1.94 2.30 1.94 1.89 2.00

5 1.86 2.10 2.00 2.15 2.03

6 2.19 2.00 2.25 1.88 2.08

7 1.95 2.16 2.13 2.00 2.06

8 2.00 2.25 2.28 2.10 2.16

9 1.90 2.30 2.00 1.90 2.00

10 1.95 2.00 2.25 2.17 2.09



S/N L1 L2 L3 L4 L5

1 2.80 3.40 3.10 2.80 3.03

2 3.00 3.00 3.50 3.00 3.13

3 3.10 3.80 2.80 3.90 3.40

4 3.13 3.10 3.10 2.90 3.06

5 3.00 3.50 3.80 3.10 3.35

6 3.60 3.10 2.90 3.10 2.80

7 2.86 3.20 3.21 2.80 3.02

8 3.50 3.60 3.10 3.40 3.40

9 3.40 3.00 3.00 3.00 3.10

10 2.90 3.50 2.80 3.20 2.80

Table 6: System performance parameters

at various pressure heads (cast-head)

Head EU qvar Cu DU Cv qavg

(m) (%) (%) (%) (%) (%) l/h

0.5 75.9 19.2 96.1 95.1 4.8 1.15

1.0 81.4 21.7 94.7 91.6 6.6 1.54

1.5 82.8 19.1 94.0 92.4 6.4 2.07

2.0 63.2 29.8 94.2 89.7 7.8 2.45

2.5 63.5 28.2 92.5 90.1 9.1 3.16

Figure 4: Plot of discharge versus pressure head on log-log scale

The manufacturer’s coefficient of variation (Cv) for example varied between 4.8 and 9.1 percent for pressure heads between 0.5 and 2.5 m, respectively. Contrary to findings by other reports specifically for commercial types of emitters (e.g. Kirnak et al., 2004), who found no systematic pattern in Cv values (indicating no obvious consistent increase or decrease with pressure), the results from this study seem to suggest that the manufacturer’s coefficient of variation tends to increase as the operating pressure increases. This therefore appears to be an important criterion for operating pressure selection. Thus from Table 6, it would seem that an operating pressure of up to 1.5 m is appropriate for this low-head, low-cost drip irrigation system. In terms of acceptability, this range is classified as being average (ASABE, 2010) but could as well cover the entire range of tested pressures in this study. Compared to Cv values for on-line non-pressure compensating emitters obtained from other studies which go beyond 30 percent (Kirnak et al., 2004), the simple emission device developed in this study appears to perform quite well.

The emission uniformity (EU) varies with pressure, emitter variation, and number of emitters discharging at a point. To some extent, this is reflected in the manufacturer’s coefficient of variation. For a point source of water application on uniform topography, recommended values of EU range from 85 to 90 percent for arid areas (ASABE, 2010). In this study, pressure heads of 1.0 and 1.5 m appear to offer acceptable EU values. Flow variation (qvar) on the other hand rules out a majority of the operating pressures except the 0.5 and 1.5 m heads which are below 20 percent, the limit for acceptability (Bralts et al, 1987).

Table 7 shows values of the performance parameters for the screw-head emission device for different


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pressure heads. A 150 mm microtube length with a 50 mm screw ware found to be appropriate. Similar results were obtained by Umara et al. (2012) using plastic drinking straws with an internal diameter of 4.0 mm and 200 mm long stuffed with spongy materials of plant origin as emission devices. Compared to the cast-head emission device, there was little variation in performance parameters with pressure. Based on these results the best operating pressure would seem to be 2.0 m at which the performance parameters remain more or less within the respective acceptable ranges.

The computed x and k values for the emitter flow function were 0.663 and 0.957 respectively. This emission device can also be classified as non-pressure compensating with a turbulent flow regime (Bralts et al., 1981). The values of x and k are similar to those reported elsewhere for commercially produced non-pressure compensating emitters, albeit at much higher operating pressures (Kirnak et al., 2004).

Table 7: System performance parameters at various pressure heads (screw-head)

Head EU qvar Cu DU Cv qavg

(m) (%) (%) (%) (%) (%) l/h

0.5 80.7 21.8 94.2 91.1 7.1 0.69

1.0 79.6 20.5 93.8 90.2 7.2 0.80

1.5 78.1 26.9 91.6 91.2 9.6 1.07

2.0 87.9 18.1 95.3 95.6 6.2 1.80

2.5 81.7 24.2 95.8 93.4 5.6 1.82

The advantage of the screw-head over the cast head emission device is that the discharge can easily be changed by adjusting the screw depth into the microtube. In case of clogging the screw can simply be removed for flushing out dirt and replaced. In all the trials conducted, no filtration of the water was done.

In terms of economics, the initial investment cost does not differ substantially from those quoted for commercially manufactured drip irrigation kits. A locally supplied kit from Family Drip System (FDS) sells at slightly over US $ 300. It is designed to irrigate 0.125 acre or 500 m2 (20 m x 25 m) without the water tank. Other drip irrigation kits supplied as packages such as the IDE “Easy Drip Kit” which makes use of microtubes (25 mm in length and 1.2 mm internal diameter) for emitters (Ella, et al., 2009) may seem to be cheaper but are reliant on imported materials such as the lay-flat tubing for the lateral and the microtubes themselves. For small-scale farmers in remote areas of the country maintenance of such kits or replacement of components could prove costly. The cost for the screw-head emission device could further be reduced by using a smaller diameter tube and consequently, smaller size screws.

Conclusion

Of the two emission devices developed and tested in this study, the screw-head type has all the qualities that match smallholders’ unique characteristics. It is therefore recommended that further tests be done on this emission device to establish optimal design parameters that will result in minimum initial investment cost.

Acknowledgement

This work is part of an on-going research project under the innovative Agricultural Research Initiative (iAGRI)), a Feed the Future Project and the authors are grateful to USAID for the financial support.

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UNEP. Earthscan, London, UK. pp 416. Upadhyay B (2004). Gender aspects of smallholder irrigation technology:

Insights from Nepal.

Journal of Applied Irrigation Science 39(2): 315-327. Vermeiren L and Jobling GA (1984). Localized Irrigation: Design,

Installation, Operation and Evaluation. FAO Irrigation and Drainage Paper No. 36. FAO, Rome. pp 203.

Wu IP and Gitlin HM (1977). Drip irrigation efficiency and schedules. Transactions of the ASAE 26(1):92-97.


14 |


ISOLATION ANd IdENTIFICATION OF YEASTS IN mNAzI

*Kadere T. T.* Corresponding author,

Department of Pure and Applied Sciences, Technical University of Mombasa (TUM),P.O. Box 90420-80100, Mombasa, Kenya, Email: [email protected], Tel. +254722285937

Abstract

Mnazi also referred to as coconut toddy or palm wine is a fermented coconut sap obtained from coconut tree. It is sweet, dirty brown in colour, containing 10-12% sugar, mainly sucrose. The yeasts in coconut toddy were identified using API 20 C AUX and API ID 32 C test kits. A total of 35 yeast strains out of 198 isolates were identified in this study. Almost 75% of all the isolated strains belonged to the genera Saccharomyces. The API C AUX system identified 24 species as Saccharomyces cerevisiae 1 (68.6%), 2 species belonged to Saccharomyces cerevisiae 2 (5.7%). The other isolates were identified as Candida pelliculosa (5.7%), Candida utillis (5.7%), Stephanoascus ciferrii (2.8%), Kloeckera spp (2.8%), Trichosporon asahii (2.8%) and Rhodotorula mucilaginosa (2.8%). While API C AUX system was able to identify at least 9 different species from mnazi, API ID32 C on the other hand classified all the 35 strains into only two different species, namely: Saccharomyces cerevisiae and Saccharomyces exeginuus (Candida holmii). It is expected that the findings of this study will be exploited further for local industrial application such as baking, making of wine, beer, production of portable fuel ethanol and single cell protein in addition to further work on ethanol tolerant, osmo-tolerant, acid tolerant as well as flocculating properties of these species.

Key Words: mnazi, Candida spp, Saccharomyces spp, yeasts, isolation, identification

Introduction

Mnazi also referred to as coconut toddy or palm wine is a fermented coconut sap obtained from coconut tree. It is sweet, dirty brown in colour, containing 10-12% sugar, mainly sucrose (Faparusi, 1971). As the fermentation process continues, the sap becomes milky-white in appearance due to the presence of large numbers of fermenting bacteria and yeasts (Okafor, 1975). Mnazi is consumed as a mildly alcoholic beverage similar to beer. Some people consume mnazi instead of water after meals. At the coastal region of Kenya, mnazi has a special place in traditional celebrations and ceremonies such as marriage, burials and settling of disputes (Kadere et al., 2004).

Yeasts are fungi in the division of Ascomycota and Fungi imperfecti. Humans have known yeasts for thousands of years as they have been used in fermentation processes like in the production of alcoholic beverages and bread leavening. Yeasts have previously been isolated from the fermenting sap of mnazi, e.g. Elaesis guineansis (Basir, 1962).

There is a widespread belief that coconut toddy is a rich source of the B-complex vitamins on account

of the yeast present, although there appears to be no experimental evidence in support of this view. On the other hand, Anonymous (1941) reported the presence of vitamin B in coconut toddy in the early forties. Browning and Symons (1916) isolated from fermented coconut toddy several strains of Saccharomyces cerevisiae, together with other forms that resembled S. ellipsoideus, Schizosaccharomyces mellacei, Zygosaccharomyces barker; and Saccharomycodes ludwigii. No species of Mycoderma or Torula or film-forming yeast was found. Availability studies have indicated that thiamine in live yeast is poorly utilized by human subjects (Parsons, Williamson and Johnson, 1945; Hochberg, Melnick and Oser, 1945; Kingsley and Parsons, 1947).

In the field of applied biotechnology, fermentation of glucose and fructose has been established through thousands of years of practice. Most ethanol produced in the world is derived from starch or sucrose (Gong et al., 1999). These carbohydrates are readily hydrolyzed by enzymes present in yeasts especially Saccharomyces cerevisiae and a few other yeasts with the production of alcohol (beer) and gas (bread leavening) (Vaughn-Martini and Martini, 1995). It has been established that only plant material that contains fermentable



| 15


sugars provides suitable substrates for yeast species of Saccharomyces, Candida, Torula and Hansenula (Campbell-Platt, 1994). These yeasts, especially Saccharomyces are typically associated with

spontaneous alcoholic fermentation of African opaque beers; mnazi and Asian type of beverages such as rice wine (Campbell-Platt, 1994). Food grade yeasts are also used as sources of high nutritional value proteins, enzymes and vitamins, with application in the health food industries as nutritional supplements, as food additives, conditioners and flavouring agents. They are also used in the production of microbiology media, as well as livestock feeds. Yeast are included in starter cultures, for the production of specific types of fermented foods like cheese, bread, sour dough, fermented meat and vegetable products, vinegar, etc.

The significance of yeasts in food technology as well as in human nutrition, as alternative sources of protein to cover the demands in a world of low agricultural production and rapidly increasing population, makes the production of food grade yeasts important. A large part of the earth’s population is malnourished, due to poverty and inadequate distribution of food. Scientists are concerned whether the food supply can keep up with the pace of the world population increase, with the increasing demands for energy, the ration of land area required for global food supply or production of bio-energy, the availability of raw materials, as well as the maintenance of wild biodiversity (Bekatorou et al., 2006).

Various microorganisms are used for human consumption worldwide as single cell protein (SCP) or as components of traditional food starters, including algae (Spirulina, Chlorella, Laminaria, Rhodymenia, etc), bacteria (Lactobacillus, Cellulomonas and Alcaligenes etc), fungi (Aspergillus, Penicillium, etc) and yeasts (Saccharomyces, Candida, Kluyveromyces, Pichia and Torulopsis) (Jay, 1996; Ravindra, 2000). Among the yeast species, Saccharomyces cerevisiae and Candida utilis are fully accepted for human consumption, but very few species are commercially available. This study was undertaken, to isolate, enumerate and identify the common yeast strains in coconut toddy tapped by traditional methods by the coastal people of Kenya so as to avail them for future economic use in the food and biotechnology industries.


Sample

Samples of mnazi were obtained from Chonyi and Kikambala areas of the coastal region of Kenya. The samples were collected in sterile sampling tubes. The pH of the sample was determined at the sampling site using a portable pH meter. The samples were kept at 4°C and transported in cool boxes packed with dry ice to the Food Science and Technology Laboratory at the Jomo Kenyatta University of Agriculture and Technology (JKUAT). To ensure consistency, three tappers were selected as sources of the required samples. Their selection was based on their consistency in the way they conducted their tapping process. Another factor that was used in the selection exercise was variation in execution of the tapping technology. According to Kadere et al. (2004), there is little or no variation in the traditional mnazi tapping, samples collected from three tappers were found to be adequate to provide conclusive results.

Isolation and preservation of yeasts strains

Before isolation, the samples were enriched in litmus milk medium (0.5% yeast extract, 0.5% glucose and 100ppm chloramphenicol). The actual isolation and identification of suspected yeasts was carried out in Yeast extract-Malt extract (YM) agar (0.3% yeast extract, 3% malt extract, 0.5% peptone 1% glucose and 1.8% agar). Triplicate pour plates were prepared for each dilution and the plates were incubated at 25, 30 and 37°C, respectively for a period of 1-2 days. Isolates were picked from plates with less than 30 colonies. Pure colonies of the selected isolates were obtained by transferring three times from the YM agar into Tryptone-Yeast extract-Lactose- Glucose (TYLG) broth (yeast extract 0.5%, tryptone 1%, glucose 0.5%, lactose 0.5%, tween-80 0.1%, L-cysteine 0.01%) or YM broth (0.3% yeast extract, 3% malt extract, 0.5% peptone and 1% glucose). Thereafter, one loop full of inoculum from each tube, which had shown positive growth, was streaked onto plates with YM agar for further isolation of pure cultures. After incubation for 1-2 days, the same exercise was repeated until three transfers were made. The isolated pure culture colonies were Gram stained before the representative colonies of the isolated yeasts were stored in agar slants of YM agar at 4°C and transferred every 2 months or stored in skim milk medium (skim milk 10%, L-glutamic acid monosodium salt 0.1%) at -20°C until identification.


16 |


Preliminary physiological and biochemical tests

Based on morphological observation of the isolated strains after Gram stain, a total of one hundred and ninety eight (198) different colonies were picked and grouped according to morphological differences and similarities such as shape and size. Based on these differences the number was reduced further to thirty five (35). The 35 isolates were picked and purified further by streaking at least three times on YM agar. The isolates were stored in agar slants of YM agar at 4°C and transferred every 2 months or stored in skim milk medium at -20°C until required for identification.

Growth at 37°C was determined using 1% of a fresh culture previously transferred three times on YM broth was inoculated into a special broth containing yeast extract (0.5%), glucose (2%) and peptone (1%). Incubation was done at 37°C for 3 weeks and the presence of any growth in form of gas production, turbidity or sedimentation was considered a positive result.

For growth in cycloheximide, 0.5ml of glucose assimilation medium was added into 4.5ml of filter-sterilized solution of cycloheximide (10mg of cycloheximide was dissolved in 90ml of distilled water). 1% of fresh culture previously transferred three times into YM broth was inoculated into the prepared medium and incubated at 25°C for 3 weeks. Any growth within one week was considered as positive result, while growth after 2-3 weeks was considered as positive/negative result.

Growth on 50% (w/v) glucose-yeast extract agar (glucose 50%, yeast 5% and agar 3%) was carried out by transferring 1 straight wire of culture previously transferred three times in YM broth onto the 50% glucose-yeast extract agar. Incubation was done at 25°C for one month, any growth was considered as a positive result.

Determination of hydrolysis of urea was done using the method of Van der Walt and Yarrow (1984). Commercially produced Christensen’s urea agar base (Merck) was used. The slants were inoculated from a suspension of the actively growing yeast culture using a sterile wire loop and incubated at 25°C for 4 days. The development of a deep pink colour in the agar was considered as a positive reaction.

Formation of mycelium was examined on corn meal agar (Merck). About 7 ml of the medium was poured onto the top of a sterile glass slide and this was allowed to solidify. By making two streaks on the surface of with a straight wire containing fresh culture previously prepared three times on the slide with corn meal agar. The slides were then placed on top of a horse shoe type of glass rod immersed in a Petri dish containing 7-10ml of distilled water. The Petri dish was covered before incubation at 25°C for 5-7 days. Microscopic observations of the wet mount were done after every three days for any formation of mycelium or pseudo-hyphae.

Fermentation and liquid assimilation of carbon compounds

Fermentation of D-glucose, sucrose, D-galactose, lactose, maltose and raffinose was tested according to the description of Van der Walt and Yarrow (1984). A


| 17


positive result was indicated by accumulation of gas in the Durham tubes.

Liquid assimilation of carbon compounds was carried out by adding 4.5ml of distilled water into small test tubes with caps previously oven sterilized at 175°C for a period of 1.5h. Each tube with distilled water was sterilized by autoclaving at 121°C for 15min. An aliquot (0.5ml) of filter sterilized yeast nitrogen base (Difco laboratories, Detroit, MI, USA) containing 5% of the compound under test was aseptically added to the tubes. The tubes were inoculated by aseptically adding 0.1ml of a viable suspension in Ringers solution (Oxoid) of an actively growing culture. The carbon compounds tested were galactose, glucose, sucrose, lactose, L-arabinose, maltose, D-mannitol, melibiose, raffinose, soluble starch, Trehalose, xylose, a -methyl-D-glucoside, Cellobiose, Erythritol, Xylitol, citrate and DL-lactate. The tubes were inoculated as in the sugar fermentation tests. A positive reaction was detected by visual inspection for an increase in the turbidity of the solution.

API 20 C AUX kits test

Portions of growth of each isolate were aseptically transferred from a freshly inoculated stock culture to an ampule of API 20 C AUX basal medium and the emulsified to give a final turbidity equivalent to McFarland standard #2. Each well of the API 20 C AUX strip was inoculated with the suspension, and the strip was placed in the incubation tray provided by the manufacturer, covered loosely with a lid, and incubated at 30°C for 72h. Reactions were visually examined at 24, 48 and 72h and determined to be positive or negative based on the presence or absence of turbidity in the carbohydrates wells. A seven –digit biocode was generated on the basis of these observations by assigning a weighted score to positive reactions. These codes were then compared to those listed in the API 20 C AUX Analytical Profile Index. The results, which form biochemical profiles, were identified using an apiwebTM software version 4.0. Identifications listed in the index as excellent, very good or acceptable were accepted as correct. This together with other supplementary tests described above such as presence of nuclei, presence of hyphae or pseudohypha were used to confirm the strains.

Further tests by API ID 32 C kits

Further confirmation of the isolates positively identified as Saccharomyces cerevisiae was conducted using an API ID 32 C kit. Identification was accomplished

as directed by the manufacturer (bioMèrieux). The molten API basal medium ampoules were inoculated with yeast cells picked from individual colonies and the resulting suspension was standardized to turbidity equal to McFarland standard #2. Each ampoule was inoculated and trays were incubated for 72h at 30°C. Ampoules showing turbidity significantly greater than that of the negative control were considered positive. A ten–digit biocode was generated on the basis of these observations by assigning a weighted score to positive reactions. These codes were then compared to those listed in the API ID 32 C Analytical Profile Index. The results, which form biochemical profiles, were identified using an apiwebTM software version 3.0. Morphology on cornmeal agar (Difco) was also evaluated as suggested by the manufacturer.

Results

Preliminary physiological and biochemical identification

A total of thirty five (35) yeast strains out of the isolated one hundred and ninety eight (198) isolates from mnazi were identified in this study (Tables 1, 2 and 3). The morphological observation yeasts under Gram stain are shown in Figure 1, while the ability to hydrolyze urea is as shown in Figure 2. A deep pink colour indicates positive test.

The physiological and biochemical characteristics of the isolates are provided in Table 1. All the isolates under investigation registered positive growth at 37°C and they were able to grow at 50% glucose. As shown in Table 1, isolates that were grouped as Saccharomyces cerevisiae, seem to confirm the identification given by Van der Walt and Yarrow (1984) in that they had shown: positive growth at 37°C, ability by most species to grow at 50% glucose, negative growth in cycloheximide (most of the species) and inability by most species to degrade urea.

In addition all the isolates from mnazi were able to ferment the following sugars: glucose, galactose and sucrose. While all were not able to ferment maltose and lactose but a few were able to ferment raffinose (Table 1). As for the assimilation of sugars with the production of carbon dioxide, all isolates were able to assimilate glucose, galactose and sucrose. Some were able to assimilate maltose, raffinose and α-Methyl-D-glucoside, while all were not able to assimilate cellobiose, trehalose, lactose, melibiose, erythritol and succinic (Table 1).


Tab

le 1

: Id

enti

fica

tion

of

yeas

ts is

olat

ed fr

om m

nazi

usi

ng p

hysi

olog

ical

and

mor

phol

ogic

al c

hara

cter

isti

cs a

s w

ell a

s fe

rmen

tati

on a

nd

assi

mila

tion

of

carb

on c

ompo

unds

S. N

o.01

0203

0405

0607

0809

1011

1213

1415

1617

1819

20

Stai

n R

efere

nce N

o.M

M

2532

MM

25

36M

M25

65M

M30

35M

M30

53M

M37

41M

M37

59M

M25

46M

M25

51M

M25

61M

M30

83M

M30

42M

M37

51M

M30

55M

M30

52M

M30

34M

M35

57M

M30

61M

M30

84M

M37

58

Ferm

enta

tion

of:

Glu

cose

++

++

++

++

++

++

++

++

++

++

Gal

acto

se+

++

++

++

++

++

++

++

++

++

+

Sucr

ose

++

++

++

++

++

++

++

++

++

++

Mal

tose

--

--

--

--

--

--

--

--

--

--

Lact

ose

--

--

--

--

--

--

--

--

--

--

Raf

finos

e-

-+

-+

-+

-+

-+

+-

+-

-+

--

-

Assi

mila

tion

of:

Glu

cose

++

++

++

++

++

++

++

++

++

++

Gal

acto

se+

++

++

++

++

++

++

++

++

++

+

Sucr

ose

++

++

++

++

++

++

++

++

++

++

Mal

tose

-+

-+

--

--

++

++

++

++

-+

++

Cel

lobi

ose

--

--

--

--

--

--

--

--

--

-

Treh

alos

e-

--

--

--

--

--

--

--

--

--

-

Lact

ose

--

--

--

--

--

--

--

--

--

--

Mel

ibio

se-

--

--

--

--

--

--

--

--

--

-

Raf

finos

e-

+-

++

++

-+

-+

-+

++

+-

++

-

Ery

thrit

ol-

--

--

--

--

--

--

--

--

--

-

MD

G-

--

--

+-

++

--

++

++

+-

--

-

Succ

inic

-

--

--

--

--

--

--

--

--

--

-

Oth

er T

ests:

At 3

7 °C

++

++

++

++

++

++

++

++

++

++

50 %

Glu

cose

+/-

++

+/-

++

++

++

/-+

++

++

++

++

+

In C

yclo

hexi

mid

e-

--

++

--

--

--

--

--

--

--

+

Ure

a ut

iliza

tion

-+

+-

--

--

+-

--

--

--

--

--

Pseu

dohy

phae

+-

--

--

--

--

--

--

-+

+-

--


S.N

o.21

2223

2425

2627

2829

3031

3233

3435

Stra

in R

efere

nce N

o.M

M 3

762

MM

305

1M

M 2

554

MM

376

1M

M 3

754

MM

304

1M

M 2

534

MM

306

2M

M 3

075

MM

308

1M

M 2

533

MM

254

7M

M 3

074

MM

254

3M

M 3

745

Ferm

enta

tion

of:

Glu

cose

++

++

++

++

++

++

++

+

Gal

acto

se+

++

++

++

++

++

++

++

Sucr

ose

++

++

++

++

++

++

++

+

Mal

tose

--

--

--

--

--

--

--

-

Lact

ose

--

--

--

--

--

--

--

-

Raf

finos

e-

--

--

--

--

+-

--

+-

Assi

mila

tion

of:

Glu

cose

++

++

++

++

++

++

++

+

Gal

acto

se+

++

++

+-

-+

++

++

++

Sucr

ose

++

++

++

++

++

++

++

+

Mal

tose

++

--

--

--

-+

-+

--

-

Cel

lobi

ose

--

--

--

--

--

--

--

-

Treh

alos

e-

--

--

+-

++

++

++

++

Lact

ose

--

--

--

+-

--

--

+-

+

Mel

ibio

se-

--

--

--

--

+-

-+

--

Raf

finos

e-

+-

--

+-

++

++

++

++

Ery

thrit

ol-

--

--

--

--

--

--

--

MD

G-

++

+-

+-

-+

-+

+-

++

Succ

inic

-

--

--

--

--

--

--

--

Oth

er T

ests:

At 3

7 °C

++

++

++

++

++

++

++

+

50 %

Glu

cose

++

++

++

++

++

++

++

+

In C

yclo

hexi

mid

e+

/--

-+

/-+

/--

--

--

-+

--

-

Ure

a ut

iliza

tion

--

+-

+-

--

--

-+

+-

-

Pseu

dohy

phae

--

-+

--

--

--

--

--

+

+/-

= w

eak,

+ =

pos

itive

test

, - =

neg

ativ

e te

st


Tab

le 2

: Ide

ntif

icat

ion

of y

east

isol

ates

wit

h th

e A

PI

20 C

AU

X S

yste

m

S. N

O.

01 –

07

08 –

09

10 –

11

1213

– 1

4 15

1617

1819

2021

2223

24

Test

N

os.

Stra

in R

efer

ence

NO

.

MM

2532

, M

M25

36,

MM

2565

, MM

3035

, M

M30

53, M

M37

41,

MM

3759

MM

2546

, M

M25

51,

MM

2561

, M

M30

83M

M30

42M

M30

51,

MM

3751

MM

3055

MM

3052

MM

3034

MM

MM

3557

MM

3061

MM

3084

MM

3758

MM

2554

MM

3762

MM

3761

0C

ontr

ol-

--

--

--

--

--

--

--

1D

-Glu

cose

++

++

++

++

++

++

++

+

2G

lyce

rol

--

--

--

+-

--

+-

--

-

32

ceto

- glu

cona

te-

--

--

--

--

--

--

--

4A

rabi

nose

--

--

--

--

--

--

--

-

5X

ylos

e-

--

--

--

--

+-

--

--

6A

doni

tol

--

--

--

--

--

--

--

-

7X

ylito

l-

--

--

--

--

-+

--

--

8G

alac

tose

++

++

++

+-

-+

+-

+-

+

9In

osito

l-

--

--

--

--

--

--

--

10So

rbito

l-

--

--

--

--

--

--

--

11α-

Met

hyl-D

-glu

cosi

de-

+-

++

++

--

-+

-+

--

12N

-Ace

tyl–

gluc

osam

ine

--

--

--

--

--

--

--

-

13C

ello

bios

e-

--

+-

--

--

+-

--

--

14La

ctos

e-

--

--

--

--

--

--

--

15M

alto

se-

-+

++

-+

-+

/-+

+-

++

-

16Sa

ccha

rose

++

++

++

++

++

++

++

+

17Tr

ehal

ose

--

--

--

--

--

--

--

-

18 M

elez

itose

--

--

--

--

--

-+

--

-

19R

affin

ose

-+

-+

+-

+-

--

+-

--

-

20H

ypha

e/ P

seud

o-H

ypha

e-

--

--

--

-+

--

--

--

Leve

l of

Iden

tifica

tion

LDV

GI

VG

IG

IG

IV

GI

GI

GI

GI

VG

IG

ILD

VG

IG

ILD

Iden

tifica

tion

%91

.699

.799

.597

.997

.999

.894

.091

97.5

99.5

98.1

74.7

99.2

97.5

74.7

Test

0.89

0.79

0.97

0.86

0.86

0.75

0.82

0.89

0.81

0.97

0.69

0.97

0.83

0.81

0.97

Test

aga

inst

MA

LM

AL

NIL

GLY

MD

GM

GD

GLY

MA

LG

AL

NIL

GLY

MA

LM

DG

GA

LM

AL

Iden

tified

as:

Sach

arom

yces

cerev

isiae


Tab

le 2

: (C

onti

nued

)

S.N

o.25

2627

2829

3031

3233

3435

Test

No.

Stra

in R

efere

nce N

o.M

M37

54M

M30

41M

M25

34M

M30

62M

M30

75M

M30

81M

M25

33M

M25

47M

M30

74M

M25

43M

M37

45

0C

ontr

ol-

--

--

--

--

--

1D

-Glu

cose

++

++

++

++

++

+

2G

lyce

rol

--

-+

++

++

++

+

32

ceto

- glu

cona

te-

-+

--

--

++

-+

4A

rabi

nose

+-

--

--

-+

+-

+

5X

ylos

e+

--

++

+-

++

++

6A

doni

tol

+-

--

--

--

+-

+

7X

ylito

l-

--

--

--

-+

--

8G

alac

tose

++

--

++

++

++

+

9In

osito

l-

--

--

--

+-

-+

10So

rbito

l-

--

--

--

-+

--

11α-

Met

hyl-D

-glu

cosi

de-

+-

--

++

--

++

12N

-Ace

tyl–

gluc

osam

ine

--

--

--

-+

+-

+

13C

ello

bios

e-

--

-+

++

+-

-+

14La

ctos

e-

--

--

--

-+

-+

15M

alto

se+

--

++

++

++

++

16Sa

ccha

rose

++

-+

++

++

++

+

17Tr

ehal

ose

-+

--

-+

++

++

+

18 M

elez

itose

--

--

-+

--

--

-

19R

affin

ose

++

-+

++

++

++

+

20H

ypha

e/ P

seud

o-H

ypha

e-

--

--

--

+-

-+

Leve

l of

Iden

tifica

tion

VG

IV

GI

GI

VG

IV

GI

GI

VG

IE

IV

GI

EI

EI

Iden

tifica

tion

%99

.372

.695

.299

.499

.499

.898

.799

.999

.499

.399

.9

Test

1.0

0.53

0.79

0.88

0.63

0.83

0.83

0.91

0.91

0.72

0.70

Test

Aga

inst

NIL

MA

LC

EL

NIL

GA

LN

ilM

LZN

ILM

LZG

LY

Iden

tified

as

S. ce

revis

iae2

Klo

spp

C.

utili

sC

. pell

iculos

aSt

eph.

cifer

riiS.

clor

.R

h. M

ucila

ginos

a 2

Tr. a

sahi

i

+ =

pos

itive

test

, - =

neg

ativ

e te

st, E

I =

exc

elle

nt id

entifi

catio

n, V

GI

= v

ery

good

iden

tifica

tion,

GI

= g

ood

iden

tifica

tion,

S. =

Sac

char

omyc

es, C

. = C

andi

da, K

lo s

pp =

Klo

ecke

ra s

peci

es, S

teph

. = S

teph

anoa

scus

, Rho

doto

rula

. = T

r- =

Tric

hosp

oron


Tab

le 3

: Ide

ntif

icat

ion

of y

east

isol

ates

wit

h th

e A

PI

20 C

AU

X S

yste

m

S.N

o.01

– 1

9 20

– 2

223

24 –

32

33 –

35

Test

Nos

.St

rain

Ref.

No.

MM

2532

, MM

2536

, MM

2546

, MM

2551

, MM

2565

, MM

3035

, M

M30

42, M

M30

51,M

M30

53, M

M30

55, M

M30

52, M

M30

83, M

M37

58,

MM

2561

, MM

3557

, MM

3761

, MM

3034

, MM

2554

, MM

2534

MM

3751

, MM

3759

, M

M30

62M

M25

43M

M30

41*,

MM

3754

*, M

M30

74*,

M

M30

75*,

MM

3081

*, M

M37

45*,

M

M25

33,

MM

2547

*, M

M37

62*

MM

3061

, M

M30

84, M

M37

41

0G

AL

+-

++

+SO

R-

--

--

1A

CT

--

--

-X

YL

--

--

-2

SAC

++

++

+R

IB-

--

--

3N

AG

--

--

-G

LY-

--

--

4LA

T-

-+

--

RH

A-

--

--

5A

RA

--

--

-PL

E-

--

--

6C

EL

--

--

-E

RY-

--

--

7R

AF

++

++

+M

EL

--

--

-8

MA

L-

--

--

GR

T-

--

--

9T

RE

--

+-

-M

LZ-

--

--

A2K

G-

--

--

GN

T-

--

--

BM

DG

++

++

-LV

T-

--

--

CM

AN

--

--

-G

LU+

++

++

DLA

C-

--

--

SBE

--

--

-E

INO

--

--

-G

LN-

--

--

Leve

l of

Iden

tific.

Goo

d Id

entifi

catio

nG

ood

Iden

tific.

Goo

d Id

entifi

c.G

ood

Iden

tifica

tion

Low

Dis

crim

in.

Iden

tific.

%94

.2%

95.5

%98

.1%

94.2

%95

.8%

Test

0.73

0.69

0.72

0.73

0.95

Test

Aga

inst

MA

L M

AL

MA

LM

AL

TR

E

Iden

tified

as:

Sacc

haro

myc

es c

erev

isia

eC

. hol

mii

+ =

pos

itive

test

, - =

neg

ativ

e te

st


| 23


Identification by API C AUX and API ID32 C

The API C AUX system identified twenty-four (24) species as S. cerevisiae 1 (68.6%), two (2) species belonged to S. cerevisiae 2 (5.7%). Almost 75% of all the isolated strains belonged to the genera Saccharomyces. The other isolates were identified as Candida pelliculosa (5.7%), Candida utillis (5.7%), Stephanoascus ciferrii (2.8%), Kloeckera spp (2.8%), Trichosporon asahii (2.8%) and Rhodotorula mucilaginosa (2.8%). While API C AUX system was able to identify at least nine (9) different species from the coconut toddy, API ID32 C on the other hand classified all the 35 strains into only two different species, namely: Saccharomyces cerevisiae and Saccharomyces exeginuus (C. holmii). According to API ID32 C all the species isolated from mnazi belonged to the genera Saccharomyces hence API 20 C AUX together with other additional tests such as growth at 50% glucose, growth in cycloheximide and formation of mycelium were used to identify the other strains.

Discussion and Conclusions

From the results, all the twenty four (24) strains of yeasts that were successfully identified as S. cerevisiae by API 20 C AUX could ferment glucose and sucrose, while most of them were able to utilize galactose, raffinose, and maltose. They were not able to utilize cellobiose, trehalose, melezitose, lactose, inositol, sorbitol, arabinose, xylose and 2- ceto-gluconate. As for API ID32 C all strains that were successfully identified as S. cerevisiae were able to ferment sucrose and raffinose in addition to fermenting glucose and galactose (with an exception of three strains: MM3751, MM3759, MM3062). Two strains were identified as Candida Holmii by API ID 32C. These strains were able to ferment glucose, galactose and sucrose but they were unable to ferment maltose, lactose and raffinose. In addition to positive growth at 37 °C and 50% glucose but they were unable to degrade urea (Table 1). These results are compatible with those published by Van der Walt and Yarrow (1984). However, further study such as RapID Yeast Plus system (Remel), Seminested PCR (snPCR), Antigen Detection may however be necessary so as to support this assumption. Detailed results on identification of different yeast species are provided in Tables 1,2 and 3.

Mnazi which is commonly referred to as coconut toddy or Nigerian wine is produced and consumed in very large quantities in the coastal region of Kenya as an

alcoholic beverage, however through research; the yeasts isolated from mnazi could be utilized as starter cultures in fermentation and baking industries.

In recent years, several identification methods have been proposed as alternatives to cumbersome classical yeast identification techniques. Among these methods, commercial miniaturized systems such as Vitek, API 32C, API 20C AUX (bioMèrieux), Yeast Star (Clarc Laboratories, Heerlen, The Netherlands), Auxacolor (Sanofi, Paris, France), and RapID Yeast Plus system (Remel) were designed to shorten the identification.

The API 20C system (bioMerieux, Marcy-l’Etoile, France) was one of the first commercial systems to be introduced for the purpose of yeast identification (Buesching, Kurek, and Roberts. 1979; Land et al., 1979) and is now considered a reliable, proven system with which others are to be compared (Espinel-Ingroff et al., 1998; Land et al., 1979). However, even though it is faster than classical assimilation and fermentation methods, the API 20C system is still time-consuming that is, from the time the experiment is set to the time the results are read. For example it requires up to 72 h of incubation, and gives results that are often difficult to interpret.

In practice, the need for supplemental tests means retesting isolates with the API 20C or ID 32C systems, increases the cost and the time needed for identification to 72 or 96 h. Many laboratories now use commercial identification systems to determine the physiological profiles of yeast isolates. Some of these systems offer extensive databases; capable of identifying a wide range of taxa, but others are much more limited in scope. In either case, a morphological assessment of isolates remains essential to avoid errors in the identification of organisms with identical biochemical profiles. In this study, morphological coupled with physiological and biochemical characteristics (Tables 1 and 2) were conducted to supplement the results from API 20C AUX and ID 32C systems. In addition, API ID32 C test strips for yeast were used to compare the results obtained using API 20 C AUX system.

From the results, these tests seem to confirm the identification of the isolated yeast strains. However, further study may be necessary to support and confirm the identification especially for results which were doubtful. Despite being reliable, it is important to note that the API kits were developed primarily for identification of clinical yeasts (Heard, 1998).

In this study, it was observed that over 75% of


24 |


all the isolates from mnazi belonged to the genera Saccharomyces. The results (both with DI 32C and API 20C) are compatible with those of other published reports (Faparus, 1971; Okafor, 1972). For example, Okafor (1972) reported that Saccharomyces cerevisiae constitutes about 70% of the total population of yeasts in mnazi.

The fact that this study successfully isolated and identified some of the most important yeasts notably Saccharomyces cerevisiae and Candida utilis raises very strong hope for future use of these species in local biotechnology related industries such as the Muhoroni- based Agro-Chemical and Food Company and the East African Breweries limited. Previous studies have shown that among the yeast species, Saccharomyces cerevisiae and Candida utilis are fully accepted for human consumption as a single cell protein (SCP) or as component of traditional starters but very few species of these yeasts are commercially available (Jay, 1996; Ravindra, 2000). In addition S. cerevisiae has been used as a top fermentation starter culture in the production of ales, stouts and wheat beers (Goldammer, 2000).

According to Salminen et al. (1999), probiotic properties of yeasts, like S. cerevisiae have been reported and displayed as the ability to survive through gastrointestinal (GI) tract and interact antagonistically with GI pathogens such as Escherichia coli, Shigella and Salmonella. It will be interesting if further studies can be conducted to confirm any probiotic properties of these yeast species, since unconfirmed reports indicate that heavy consumers of mnazi at the coastal region of Kenya are more resistant to common and opportunistic diseases such as typhoid, diarrhoea, malaria, common flu and fever.

In the animal feed industry, Torula or Candida yeast refers to products containing Candida utilis, which have been used commercially for more than 60 years as nutritional supplements in feeds. Food grade Torula yeast is cultivated in mixtures of sugars and minerals, usually containing molasses, cellulosic wastes (e.g. spruce wood) or brewing by-products (Lezcano, 2005; Kuzela et al. 1976; Weatherholtz and Holsing, 1975). Once thermolyzed and spray dried, Torula yeast can be used as a meat substitute or food additive in many processed foods, in seasonings, spices, sauces, soups, in baby food, meat product or diet and vegetarian food (Lezcano, 2005; Kuzela et al. 1976; Weatherholtz and Holsing, 1975). The findings of this study can also be exploited for related work in the animal feed industry.

As for the other yeast strains isolated and identified in this study Candida pelliculosa, Candida utillis, Stephanoascus ciferrii, Kloeckera spp, Trichosporon asahii and Rhodotorula mucilaginosa have also been reported in yoghurt, cheese and makamo (Tzanetakis et al., 1998; Viljoen, 1998; Sserunjogi, 1999). Candida holmii has been reported in milk due to its ability to utilize galactose. This yeast has an inducible hexokinase (which phosphorylates glucose) and a constitutive galactokinase; galactose will be used first even in the presence of glucose (Marshall, 1993). Rho. rubra (mucilaginosa) is associated with products based on milk facts (Jakobsen and Narvhus, 1996).

During this study, it was found that the identification of all common yeast isolates by the two systems (API ID 32C and API 20C) were comparable in their overall efficacy; however, the interpretation of test results obtained with ID 32C system was more difficult and required greater experience than did interpretation of those obtained with API 20C. This, therefore, explains the reason why a mismatch of about 11 strains was detected between the two systems. This calls for further study using modern and more accurate methods such as the RapID Yeast Plus system (Remel), Semi-nested PCR (snPCR), Antigen Detection and other Biochemical Methods to confirm the mismatched species and those which were successfully identified by the two systems.

However, it is worthy to note that this study successfully identified twenty four (24) species of Saccharomyces cerevisiae which can be exploited further for local industrial application such as baking, making of wine, beer, production of portable fuel ethanol and single cell protein. This therefore, calls for further work on ethanol tolerant, osmo-tolerant, acid tolerant as well as flocculating properties of these species. There is also need to conduct further work on suitability and optimum conditions for their use in the baking and fermentation industries. In addition, this study highly recommends further work to be conducted so as to ascertain the probiotic properties of the isolated and identified yeast species belonging to S. cerevisiae.

Acknowledgements

The author would like to thank the Matsumae International Foundation (MIF) for the fellowship award, without which this study would not have been successful. Special thanks go to the Department of Animal Food Functions, Okayama University for


| 25


the provision of facilities and enabling environment for the study. The authors express their gratitude to the Agricultural Research Fund (A.R.F) – Kenya Agricultural Research Institute (KARI), for the provision of financial support for the main project

entitled “Study and Improvement of Palm wine Alcoholic Beverage”, Project No. ARF/PHT/I005024/1. This paper was part of the PhD work for the first author.

References

Anonymous (1941). Health Bulletin, no. 23, 3rd ed. New Delhi: Manager of Publications.

Bassir O (1962). Observation on the fermentation on palm wine. West Afric. J. Biol. Appl. Chem. 6: 20-25.

Bekatorou A, Psarianos C, Koutinas AA (2006). Production of food grade yeasts. Food Technology Biotechnology, 44(3): 407-415.

Browning KC, Symons CY (1916). J. Soc. Chem. Ind., Lond. 35:1138.

Buesching WJ, Kurek K, and Roberts GD (1979). Evaluation of the modified API 20C system for identification of clinically important yeasts. J. Clin. Microbiol. 9:565–569.

Campbell-Platt G (1994). Fermented foods- a world perspective. Food Research international, 27: 253-257.

Deak T, Beuchat LR (1996). Handbook of food spoilage yeasts. Boca Raton, FL: CRC Press.

Espinel-Ingroff A, Stockman L, Roberts G, Pincus D, Pollack J, and Marler J (1998). Comparison of RapID Yeast Plus system with API 20C system for identification of common, new, and emerging yeast pathogens. J. Clin. Microbiol. 36:883–886.

Faparusi SI (1971). Microflora of Fermenting Mnazi. J. Food Science Technology, 8: 206-10.

Goldammer T (2000). The Brewers’ Handbook. The complete Book to Brewing Beer, Apex Publishers, Clifton, Virginia, USA.

Gong CS, Cao NJ, Du J, Tsao GT (1999). Ethanol production from renewable resources. Adv. Biochem. Eng. Biotechnol. 65: 207-241.

Heard GM, Fleet GH, Praphailog W, Addies E (1998). Evaluation of the BIOLOG system for identification of yeasts from cheese. In M. Jakobsen, J. Narhus, & B.C. Viljoen, Yeasts in the dairy industries: Positive and negative aspects, Proceedings of the symposium organized by Group F47, 2-3 September 1996 (pp. 117-124).

International Dairy Federation, Brussels, Belgium.

Hochberg M, Melnick D, Oser B L (1945). J. Nutr. 30, 201.

Jakobsen M, Narvhus J (1996). Yeasts and their possible beneficial and negative effects on the quality of dairy products. International Dairy Journal, 6: 755 – 768.

Jay JM (1996). Modern Food Microbiology, Chapman and Hall, New York, USA.

Kadere TT, Oniang`o RK, Kutima PM, Muhoho SN (2004). Traditional tapping and distillation methods of mnazi (mnazi) as practised in the Coastal region of Kenya. Afr. J. Food Agric. Nutr. Dev. 4(1): 1-16.

Kingsley HN, Parsons HT (1947). J. Nutr. 34, 321.

Kuzela L, Masek J, Zaiabak V, Krjmar J (1976). Some aspects of biomass of Torula in human nutrition – New Protein source, Bibl. Nutr. Dieta, 23: 169 – 173.

Land GA, Harrison BA, Hulme KL, Cooper BH, and Byrd JC (1979). Evaluation of the new API 20C strip for yeast identification against a conventional method. J. Clin. Microbiol. 10:357–364.

Lezcano P (2005). Development of a protein source in Cuba: Torula yeast (Candida utilis), Cuban Journal of Agric. Sci. 39: 447 – 451.


26 |


Marshall VM (1993). Starter cultures for milk fermentation and their characteristics. Journal of Science of Dairy Technology, 46(2): 49 – 56.

Okafar N (1975). Microbiology of Nigerian mnazi with particular reference to bacteria. J. Appl. Bacteriol. 38: 81-88.

Okafor N (1972). The source of the microorganisms in palmwine. Symp. Nig. Soc. Microbiol. 1: 97.

Parsons HT, Williamson A, Johnson ML (1945). J. Nutr. 29, 373.

Ravindra AP (2000). Value-added food: Single cell protein, Biotechnology Advances 18: 459-479.

Salminen S, Ouwehand A, Benno Y, Lee YK (1999). Probiotics: How should they be defined? Trends Food Sci. Technol. 10: 107 – 110.

Sserunjogi ML (1999). Ugandan indigenous fermented dairy products, with particular focus on ghee. Ph.D. thesis, Agricultural University of Norway as Norway.

Tzanetakis N, Hatzikamari M, Litopoulo–Tzanetaki E (1998). Yeast of the surface microflora of Feta Cheese. In M. Jakobsen, J. Narvhus, & B.C. Viljoen yeasts in the dairy industry: Positive and negative aspects, Proceedings of the symposium organized by Group F47, 2 – 3 September 1996 (pp. 70 – 77). IDF, Brussels, Belgium.

Van der Walt JP, Yarrow D (1984). Methods for isolation, maintenance, classification and identification of yeasts. In N.J.W. Kreger-van Rij, The yeasts: A taxonomic study (pp. 45 – 105). Amsterdam: Elsevier Science.

Vaughn-Martini A, Martini A (1995). Facts, myths and legends on the prime industrial microorganism. J. Ind. Microbiol. 14: 514-522.

Viljoen BC (1998). The ecological diversity of yeast in the dairy industry products. In M. Jakobsen, J. Narvhus, & B.C. Viljoen, yeasts in the dairy industry: Positive and negative aspects, Proceedings of the symposium organized by Group F47, 2 – 3 September 1996 (pp. 70 – 77). IDF, Brussels, Belgium.

Weatherholtz WM, Holsing GC (1975). Evaluation of Torula yeast for use as a food supplement, Fed. Proceed. 34, 890.


| 27


Introduction

In most of the developing countries, the proportion of population with access to electricity is very low. In Tanzania for example, only about 14% in the urban areas and 4% in rural area have access to electricity (Ngeleja-Reuter, 2009). Despite the fact that developing countries have many potential electric power resources such as wind, these countries have far less electric power installed capacity. This is a major obstacle for attracting more investors to accelerate development. It is also a decelerating factor for social development especially in rural areas.

The scarcity of electric energy supply in Tanzania is mainly attributed to the following factors: high investment cost in power generation; country’s energy policy which provides no incentive to investors in

renewable energy and remoteness of potential users from the national grid.

It is uneconomical to construct a line from the grid to a village located a many kilometers away hence the need for a stand-alone system. Due to lack of electricity, the villages normally suffer a clean and safe water problem due to water pumping difficulty, poor access to flour milling machines, inadequate medical services, lack of food processing machineries, among others.

Tanzania being a tropical country has many potential wind regimes for isolated electric power generation. The major hindrance to wind power harnessing is high initial cost of acquiring a wind turbine. However, this cost could be reduced by locally manufactured wind turbine. The procedures for cost effect design and fabrication of a local wind turbine are described in the paper.

LOCAL mANUFACTURINg OF wINd TURBINE, A SOLUTION TO hARNESSINg ABUNdANTLY AvAILABLE wINd ENERgY IN AFRICA

(CASE STUdY: TANzANIA)

*1Mbwiga.J*Corresponding author

1Mechanical Engineering Department, Mbeya University of Science and TechnologyP.O Box 131, Mbeya - Tanzania

Email: [email protected]

Abstract

Renewable energy such as wind energy is abundantly available in most African countries. However, most of these countries are experiencing high energy challenges due to minimal exploitation of these resources. Of all renewable energies, wind energy is least harnessed because of initial cost and technology issues. Procurement of wind turbines has been unaffordable to these countries’ local entrepreneurs. Procurement of wind turbine involves purchasing the wind turbine system complete with generator, gearbox, switchgears and control equipment, transportation and installation. The sustainable solution to wind energy harnessing for these countries should be the local wind turbine manufacturing which uses locally available materials. Unfortunately, the local capacity to manufacture wind turbine is lacking. The author of this paper came up with guidelines of manufacturing wind turbines using cheap locally available materials. Most of the proposed materials are available in every country; these include wood, PVC, steel sheets, steel rods, scrape metal and sisal fibre. The cost effective design of locally manufactured wind turbine is described. This approach reduces the cost of wind turbine to about USD 10 - 40 per kW even though a little bit at the expense of efficiency. Since wind energy is freely available at no cost, less efficiency has little impact. Most of domestic wind turbines are battery charging systems that ensure the availability of electric power when there is no wind.

Keywords: Wind power, wind turbine, blade, wind generator, wind mill


28 |


Methodology

Using work experience, the appropriate design and manufacturing methods of wind turbine from locally available materials were suggested. Literature review was also used in order to come up with the cost effective wind turbine design for local manufacturing. The wind energy characteristics of Arumeru district wind regime in Arusha, Tanzania were used in order to explain the design procedures.

Results

Local manufacturing of a wind turbine consists of local blade material selection and construction of turbine blade, shaft and hub, electrical generator, tower and turbine control system specially designed for the stand-alone power system.

Design of Turbine Blades

There are two types of forces that are responsible to rotate the turbine which are lift and drag forces. These forces are due to pressure differentials generated by air flowing around the solid turbine blade. Lift and drag forces values could be found through integrating the pressure values along the surface of the body (along the perimeter of a section normal to the flow) as shown in Figure 1. Power that could be extracted from the wind depends on the size and geometry of the blade.

Figure 1: Forces on the Blade of a Horizontal Axis Turbine

Head wind rotates the direction of forces on the blade, lift assists the blade’s rotation and drag opposes the rotation of wind. Both forces push the blade downwind and slow the wind down. This can be determined by equations 1 and 2 given below:

()22 aL AvCLift r= …………………………. 1

()22 aD AvCDrag r= ……………………… 2

Where CL and CD are lift and drag coefficients depending on blade cross section and angle of attack which is the angle between wind direction and the turbine blade surfacer is the density of air depending on pressure, A is blade surface area and va is the apparent velocity.

Blade design needs to specify chord width and blade setting angle at each series stations along the blade length. Chord is the longest line joining the leading and trailing edges of the blade section. The angle of attack is the angle between the apparent wind speed at the actuating disc and the chord line. The head wind adds to the real wind speed to give apparent or relative wind speed.

Design of the blade consists of the following steps:

• Choosing length of blade or diameter of rotor,

• Choosing tip speed ratio,

• Deciding the number of blades,

• Determining the width of the blade,

• Find the best blade setting angle,

• Blade wall thickness depending on the required strength to weight ratio.

Choosing Diameter of Rotor

Power of the available generator or wind power output determines the turbine output as shown in Table 1.

Table 1: Rotor Diameter depending on power output

D [m] Power [Watts]

1 50 – 100

2 250 - 500

3 500 – 1000

4 1000 – 2000

5 2000 – 3000

(Source: “Wind Energy Explained”, J. F. Manwellet al, 2006)


| 29


Choosing Tip Speed

Tip speed ratio varies with the number of blades. High tip speed ratio results in high-speed generator shaft, hence high operating efficiency of the generator. It should range from 5 to 7. Choosing the number of turbine blades to be 3, the corresponding tip speed is 5.

Number of Blades:Given the tip speed ratio λ, the number of blades B could be found use equation 3:

B = 80/l2………………………………………3

Or for the best tip speed ratio, as a rule of thumb, B is chosen from Figure 2 (Ackermann, 2008).

Figure 2: Relation Between number of Blade and Tip Speed Ratio (Source: Ackermann, 2008)

Width and Blade Setting Angle

Consider an aerofoil (given CL), number of blades (B), and desired tip speed ratio (λ), the distribution of blade’s chord length (c), angle of relative wind (φ), and twist angle along the radius can be estimated from Table 2. Figure 3 shows the angles indicated in Table 2 as referred to in turbine blade geometry.

Table 2: Blade Width or Chord Length as related to twist angle

r/R Chord(c) Twist angle (deg) Angle of relative wind (deg)

0.1 1.375 38.2 43.60.2 0.858 20.0 25.50.3 0.604 12.2 17.60.4 0.462 8.0 13.40.5 0.373 5.3 10.80.6 0.313 3.6 9.00.7 0.269 2.3 7.70.8 0.236 1.3 6.80.9 0.210 0.6 6.01.0 0.189 0 5.4

(Source:”Wind Energy Explained”, J. F. Manwellet al, 2006)

Figure 3: Blade Geometry (Source:”Wind Energy Explained”, J. F. Manwellet al, 2006)

The blade width or chord length could also be calculated from an empirical formula according to Ackermann, (2008);

r

rL

whereBC

C

lj

ljp

32tan

3sin8

=

=

…………………… 4

The width of the blade at the tip could be simplified as:

C= 4D/l2B ……………………………………….. 5

For the turbine consisting of 3 blades and rotor diameter 10m, the width of blade at the tip could be calculated as:

C = 4*10/(25*3)= 0.5333 m

The turbine diameter was chosen based on the power required to be generated which was 100 kW and 3 blades is the balanced model easy to fabricate and has comparatively high tip speed ratio.

The outer chord is the most important parameter compared to the inner chord. The inner is made wider for higher starting torque and to satisfy equation 6.

Neglecting drag and to satisfy Bezt’s law

BRC r

R

29)(16

lp

= ………………………………. 6

C is inversely proportional to arbitrary radius r so the turbine blade shape should be tapered,

C is inversely proportional to the number of blades,


30 |


so few blades which will be wider blades (Ackermann, 2008).

C is inversely proportional to the square of tip speed ratio, meaning that increasing speed is decreasing width.

To find blade setting angle, graph in Figure 4 could be used.

Figure 4: Blade Angle (Source: Ackermann, 2008)

In practice straight un-tapered and untwisted blades are frequently used but at the expense of efficiency, i.e. constant width and constant blade angle.

The Generator Used in Wind Turbine

The generator may be synchronous or asynchronous. The entire design of the turbine starts with the generator output power. Wind speed and hence rotor speed is normally lower than the generator speed. In order to match the two speeds, two methods are employed:

Gearbox: multiplies the turbine rotor speed to match that of the generator. However, its disadvantage is that it involves additional initial and maintenance costs and lower effective efficiency of the turbine.

High number of poles that change with speed variation: have no added initial and maintenance costs and optimize the working efficiency (Ackermann, 2008).

The synchronous generators used in small off-grid wind turbines (up to around 10 kW) are usually permanent magnet machines. The most common electrical generator in grid-connected wind turbines of all sizes is the induction generator (with 2 pole pairs at 1500 rpm), coupled to the wind rotor through a gearbox (Ackermann, 2008).

Induction machines are generally the most common electrical machines for versatile applications. A motor always lags behind the synchronous speed, and a generator always runs faster than the synchronous speed (up to 5%). Induction machines allow for smooth connection to the grid and a certain small window of variable speed operation, due to the slippage. Whenever an electrical machine is connected to the electrical grid, its rotational speed is entirely dependent and controlled by the frequency of the grid. This means that the generator in grid-connected turbines holds and restricts the rotational speed of the whole turbine at an almost steady value (Ackermann, 2008).

Design and manufacturing of Turbine Blade

The blades are the most critical component of the wind turbine. They should have the proper shape and should be strong, elastic and as light as possible.

One suitable material for blade manufacturing is wood. Novel lightweight materials used for modern blades are glass-reinforced polyster, carbon-reinforced polyester or epoxy resin(Ackermann, 2008). Locally available materials for turbine blade depend on manufacturing methods that are mainly fabrication and casting. Based on the experience, in fabrication, thin galvanized iron sheets are reverted on an aerofoil shape frame made of small steel, aluminum or wooden bars (Figure 5). Another way could be covering the steel bar frame with knitted sisal fibre, cow-dung applied as binder and finally an oily paint is applied to seal and make it water proof.

Figure 5: Fabricated Turbine Blade


| 31


The author suggests the use of a piece of wood shaped in aerofoil and made hollow to reduce weight while maintaining rigidity of the blades. Oil paint could be applied as a seal and also in order to make it smooth. For small turbines, blades could be made of shaped steel, plastic or wooden block just like a fan. The latter is the most commonly used method by many local manufacturers in Tanzania.

Casting produces blades with smooth clearance and thus little losses. However, it is the most difficult in local manufacturing based on experience. The local materials suitable for casting of turbine blade are PVC,

thermosetting plastic such as formica, among others. To make it stronger the reinforcing materials could be either ceramic or glass fibre.

Design and Construction of the Generator

The generator that would be preferable for local manufactured turbine should consist of high number of poles that change with speed variation to avoid added initial and maintenance costs due to absence of a gear box. Figures 6 and 7 show the design and construction of the generator.

Figure 6: Generator Construction

Figure 7: Pole changing by changing winding coils inter-connections


32 |


The DC rotor winding gets power by self-excitation whereby the stator output supplies the rotor winding

through a transformer and rectifier as shown in Figures 8 and 9.

Figure 8: Self-excitation of the generator

Figure 9: Rotor DC winding supplied through slip rings

Construction of a TowerThere are two main ways of construction of tower for a wind turbine: Huge pyramidal pole made of steel or wooden trusses, and concrete hollow cylindrical pole.

A concrete hollow pole could be chosen as shown in Figure 10 so that the complete installation is as in the Figure 11.

Figure 10: Concrete Hollow Cylindrical Turbine Tower


| 33



Since wind power is available at no cost, locally manufactured wind turbines should be greatly encouraged especially to low earning societies of Tanzania as wind turbines are very expensive. Small scale local entrepreneurs have little or no access to bank loans due to strict conditions.

The cost of locally manufactured wind turbines is far lower than the imported ones. While the cost of acquiring a locally manufacture wind turbine ranges between USD 10 – 40 per kW, the cost of procuring a complete turbine with generator, gear box and others, estimated to be $ 1,000 per kW (DWIA, 2003).

The suggested materials are based on Tanzania as case study, there could be more suitable materials if the scope of research was enlarged. For any area, the

material analysis could help to find out the suitable local materials. The challenge to local manufacturers is how to manufacture a turbine according to the characteristics of wind in the area of installation in order to achieve the most possible optimum power.

Acknowledgement

This paper would not have been completed and appeared as good as it is without the assistance given to me by many individuals. I would like to sincerely thank them all collectively. To mention just a few, Dr. M. H. Mkumbwa and Prof. Kimambo from University of Dar es Salaam, Prof. P. Kurt and Prof. D. Wark from MichiganTech. University.

Finally I would like to thank my fellows for their constructive challenges and critics.

Figure 11: Complete Turbine Assembly


34 |


References

Ackermann T (2008). “Lecture Notes inCourse RET II (MJ2412)”, Department of Energy Technology, Stockholm, Sweden.

Allison HJ (1973). “An Electrical Generator with Variable Speed Input Constant Frequency Output”. In: Wind energy conversion system workshop proceeding, Washington DC, Jun 11 – 13, pp 115 – 120.

Bose B (2009).Modern power Electronics and AC drives, Prentice –hall Publishers, India.

Considene DM (1977).Energy Technology Handbook, California, McGraw-Hill Book Company, pp 6–142 to 6-174.

Danish Wind Industry Association (DWIA) (2003). Wind Power, http://www.windpower.org/en/core.htm retrieved on 30/11/2014 at 1000.

Gipe P (1999).Wind Energy Basics: A Guide to Small and Micro Wind Systems, Chelsea, Green Publishing Company.

Golding, EW (1961), “Windmills for water lifting and generation of electricity on the farm”, F.A.O., Farm power, Informal working bulletin No. 17

Hau E (2005). Wind Turbines: Fundamentals, Technologies, Application and Economics, Germany, Springer.

Kainkwa L (2008). “Wind Energy”, Lecture Notes in Other Forms of Renewable Energy Course, University of Dar es Salaam, Dar es Salaam.

Kedare SB (2007). “Wind Energy Conversion System” Lecture Notes in Energy Systems Engineering, India Institute of Technology, Mumbai.

Manwell JF, Rogers A, Hayman G, Avelar CT, McGowan JG, Abdulwahid U and Wu K (2006). “A Hybrid System Simulation Model Theory Manual”, National Renewable Energy Laboratory Subcontract No. XL-1-11126-1-1. University Of Massachusetts

Ngeleja W (2009). Interview with Reuter on Energy Status in Tanzania, April 2009.

Walker F, Jenkins N (1997).Wind Energy Technology, Chichester, John Wiley& Sons.

Warne DF (1983).Wind Power Equipment, United States of America, E. & F. N. Spon Ltd.

Wizelius T (2009).Developing Wind power Projects, Earthscan, London.


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Introduction

In Tanzania only about 14% of the urban area and 4% of rural areas have access to electricity (http://blogs.worldbank.org). The electric power generation has been growing at the rate of 6 % per annum for the period between 2000 and 2009 which is very small (Tanzania Development Plan, 2012). This growth does not seem to increase the access to electric energy in rural areas because most of them are far from the national grid such that grid extension is not economically feasible. This implies that about 75% (about 32 million)of Tanzanian population living in rural areas will not have access to electricity unless the decentralized energy resources such as mini-hydropower that requires isolated mini-grids are exploited.

Isolated mini-grid is the electric distribution network which is not connected to the main grid. Normally, it is constructed where an electric power generation plant is small and very far from the main grid such that interconnecting it is economically and technically not

feasible. Since many isolated electric power generation resources are located in rural areas, isolated mini-grid is the best way of electrifying rural areas.

Rural areas are characterized by low buying capacity which discourages investors from investing in rural electrification. In many countries rural electrification projects are subsidized. In Tanzania for instance, there is an agency called Rural Energy Agency (REA) that responsible for issuing grants for any rural electrification project. However, the project costs need to be as minimum as possible given that the funds are normally meager. Electric distribution network is one of the most costly parts of the electrification. The isolated mini-grid is supposed to be cost effective in order to have a reasonable payback period.

Before construction of the electric distribution network, survey, design and selection of materials has to be done. This paper proposes the guideline that minimizes the cost of the network while maintaining the quality.

dESIgN OF COST EFFECTIvE ISOLATEd mINI-gRId FOR RURAL ELECTRIFICATION (CASE STUdY: SImIkE mINI-hYdROPOwER PROJECT

IN mBEYA, TANzANIA)

*1Mbwiga.J*Corresponding author

1Mechanical Engineering Department, Mbeya University of Science and TechnologyP.O Box 131, Mbeya - Tanzania

Email: [email protected]

Abstract

In most third world countries, rural electrification is marginal because almost all rural electrification projects are economically infeasible. No investor could be attracted to invest in rural electrification project unless subsidized by the government. However, people in rural areas need electricity for lighting, health services and water supply, among others. As a result of this, most third world countries have started governmental agencies that deal with financing the rural electrification projects. Since the funds are always meager, the rural electrification projects ought to be cost effective. In village electrification from decentralized energy resource, electric power distribution network is the most costly element. The cost of rural electrification by using isolated mini-grid can tremendously be reduced when the cost of the mini-grid is reduced. This can be done if cost effective design of electric power network is used and local materials are used. This paper proposes a cost effective design of the rural electrification projects. The design eliminates intensive electric power distribution network survey. The design was used in Simike Mini-hydropower project in Mbeya, Tanzania and was found to be effective and efficient.

Keywords: Hydro, electric, power, grid, generation, Tanzania


36 |



The spreadsheet for computing the pole positions given the coordinates of the two extreme poles was designed based on the direction cosines and the linear distance between coordinates. When applied to Simike electric network survey, 58 pole positions were obtained from 10 pole positions measured at the site by a GPS. The 10 pole coordinates were the corner poles to avoid buildings and vegetation. Having the coordinates of every pole in the network, the line routes were drawn using Matlab. The lengths and angles of the line segments were found using the designed spreadsheet.

Standards and bylaws were used in order to decide for the line configurations and conductor sizes given transmission voltage. The chosen transmission voltage is such as to minimize transmission loses.

Results

The mini-grid survey included selecting the most effective network route which is done by assessing the possible routes to capture more customers. The lines need to be straight where possible. According to standards, it is required that the medium voltage distribution line poles be about 100 m apart and that of low voltage line be about 50 m apart, the coordinates of each and every poles should be taken using a GPS.

Given that taking records for every 100 m or 50 m is tedious, the coordinates of the poles on angles are

taken and the intermediate pole coordinates are found by considering the constant direction cosine between the poles. If the coordinates of the extreme poles are (x1, y1, z1) and (x2, y2, z2) and if the intermediate pole coordinate is (x, y, z) then the coordinate (x, y, z) is found by considering a standard distance from one extremity and the constant direction cosine (Equations1).

222222

222222

222222

)1()2()1(1

)12()22()12(12

)1()2()1(1

)12()22()12(12

)1()2()1(1

)12()22()12(12

zzyyxxzz

zzyyxxzz

zzyyxxyy

zzyyxxyy

zzyyxxxx

zzyyxxxx

++

=

++

++

=

++

++

=

++

… Equations 1

The distance (D) between the two extreme poles can be found from Equation 2 as follows:

222 )12()12()12( zzyyxxD ++=…………………………………………. Equation 2

Based on Equations 1 and 2, the spreadsheet to calculate the intermediate coordinates was designed as provided in Table1.This spreadsheet was used to calculate the distance and angle between line segments as well.

x1 y1 z1 x2 y2 z2 x y z d564987.6 8976449 1208.49 565559 8976396 1320 565085.3 8976440 1227.564 100

D l m n angle584.5984 0.977419 -0.09093 0.190747 0.00

Table 1: Calculation spreadsheet to find intermediate pole coordinates given two extreme points

The calculator in Table 1 was used in survey of Simike mini-hydropower project l, where m and n are direction cosines with respect to x, y, and z axes. Table 2 shows

the survey of the medium voltage line for Simike mini-hydropower.


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Table 2: Simike Mini-Grid

Pole # Coordinates Angle Description

1 564163 8975114 Power house

2 564252 8975105 0

3 564337 8975096 0

4 564423 8975087 0

5 564508 8975078 0

6 564594 8975069 0

7 564679 8975060 133 transf –Ibabu

8 564670 8975156 0

9 564660 8975251 0

10 564651 8975347 0

11 564642 8975442 170

12 564678.1 8975521 0

13 564714 8975600 172

14 564776 8975672 120

15 564795 8975664 168

16 564817.2 8975761 160

17 564897 8975820 135

18 564844.4 8975901 130

19 564932.7 8975943 128

20 564871.4 8976019 163

21 564862.5 8976119 176

22 564867 8976219 160

23 564933.1 8976293 152

24 564920.8 8976372 162

25 564959.1 8976448 100

26 564890.7 8976408 154 transf –Sokoni

27 564803.5 8976447 0

28 564716.3 8976486 0

29 564625 8976526 164

30 564576.2 8976577 0

31 564527 8976628 154 River side – Mlagala upstream

32 564438.6 8976636 0

33 564350.2 8976644 0

34 564260 8976652 Transf-Lufingo Hospital

T-off from sokoni 24th pole to Simike CCM

35 564987 8976449 162

36 565016 8976451 0

37 565044 8976452 0

38 565073 8976453 0

39 565101 8976455 0

40 565129 8976456 0

41 565158 8976457 0

42 565186 8976459 0

43 565215 8976460 0

44 565243 8976461 0

45 565272 8976463 0

46 565301 8976464 104 River side

47 565322 8976458 0

48 565343 8976453 0

49 565365 8976447 0

50 565386 8976441 0

51 565408 8976436 0

52 565429 8976430 0

53 565451 8976424 0

54 565472 8976419 0

55 565494 8976413 0

56 565515 8976407 0

57 565537 8976402 0

58 565559 8976396 Transf- Simike CCM

The medium voltage line therefore consisted of 58 poles, making a total length of about 3.6 km (Table 3).

Table 3 Cumulative Length of Medium Voltage Line

Medium Voltage Line Length (m)

From To

Power House Transformer 1 10

Transformer 1 Transformer 2 525

Transformer 2 Transformer 3 1,623



Total 3,543

The survey found that the low voltage (LV) line at Lufingo was about 2.4 km long because householdswere scattered. The same length could be assumed around each transformer, hence the total LV line was about 9.6 km. This was equivalent to about 192 LV poles.

The data obtained in Table 3 were fed into the matlab to give a layout as shown in Figure1.


38 |


Figure 1 Layout of Simike Mini-Grid

Discussions and Conclusion

The Simike settlement density is very low leading to a longer distribution network. So the choice of four distribution transformer ensures reaching many scattered consumers. The route was decided based on the demand analysis and location of social service centers such as hospitals and schools. There were shifts of the line from one side of the road to another to avoid households which were very close to the road to avoid demolition of structures that fall within

the distribution network. This was done to reduce cost and avoid confrontation with the public.

In most areas along the HT line there were banana plants except besides the road. Along the road the transmission line was suggested to be either vertical delta or vertical offset. Across banana plants the line was suggested tobe flat or horizontal. Between transformers 1 and 2, 3 and 4, and 3 and 5 the style was suggested to be flat, while between 2 and 3,the transmission line was suggested to be either vertical delta or offset.

For LV line, Aerial Bundled Conductor (ABC) line was suggested to be used. This ensured trouble free distribution across banana plants. ABC can stand close proximity with trees and its installation is simpler. Where it should be constructed under the HT line, LV line should be of vertical shackle structure.

While connecting consumers it should be ensured that the voltage drop does not lead to low voltage at

the extreme ends of the lines. The demand survey estimated the daily power demand of the village to be 750 kWh assuming an average power usage of 5 hours. From this the connected loads would be 150 kW, assuming that all the loads were at the same time. If the loads were assumed to be purely resistive then this power could undoubtedly be provided by the selected generator of 200 kVA. For 11 kV transmission voltage, the rated current would be 18.2 A. For the chosen copper conductor of 50 square mm, the line resistance per meter was 0.0003355 Ω. For the total length of 3,543 m, the total line resistance was 1.3 Ω. The total line drop will be 21.64 V at rated current. So the farthest point voltage was 10978.4 V.

The designed spreadsheet helped to find other poles’ coordinates using few measured coordinate thereby reducing the surveying cost tremendously. The commonly used method required a professional surveyor and expensive equipment called Theodolit or Total Station. While measuring, each and every pole coordinate has to be measured. The suggested method can be easily adapted by a non-professional surveyor.

The line voltage drop was very low to cause low voltage problems for the farthest connected consumers. It is important to consider the line drop because in village electrification according to the author’s experience there are many complaints by farthest consumers on failure to operate some loads like welding machines due to low voltage.

Construction of Smike Mini-hydropower is


| 39


recommended to occur in parallel with the construction of the mini-grid so that the impact of the hydropower could be felt immediately by the stakeholders. Many completed power generation projects take a long time before people starts enjoying them because either there was no plan of constructing mini-grid or delay of mini-grid construction.

The author recommends that the technology being suggested be adopted and further research should be conducted to improve its efficiency.

Acknowledgement

The author acknowledges the contribution of many individuals; just to mention a few: Mr. Kiyeyeu, TANESCO Mbeya planning engineer; Emmanuel Michael, director Nishati Associate.

I extend my sincere appreciation to the CAPA Editorial Board which tirelessly edited this paper and gave worthy comments and suggestions to come up with a final version. Finally, I would like to thank the Management of MUST for their sponsorship that enabled me to attend CAPA Conferences which gave me the necessary experience to write a proceeding and journal papers. I wish to thank CAPA secretariat for inviting me to submit my manuscript.

References

Energy Services Delivery/Renewable Energy for Rural Economic Development Projects (Sri-Lanka), “Village Hydro Specifications.” 1999. http://www.energyservices.lk/pdf/techspecs/vh_w_b/line.pdf

Horstead A (2012). Overhead Line Design Manual – Section 1 – LV ABC v1.2 Institute of Electrical and Electronics Engineers, “IEEE Guide for Design, Operation, and Integration of Distributed Resource Island Systems with Electric Power Systems,” IEEE Std 1547.4,Jul. 20, 2011.

Inversin AR (2000). Mini-Grid Design Manual. America

Joint UNDP/World Bank Energy Sector Management Assistance Program (ESMAP), “Mini-Grid Design Manual,” Technical Paper 007, Sep. 2000. http://www.riaed.net/IMG/pdf/Mini-Grid_Design_Manual-2.pdf

Module Handout: Design overhead distribution systems. Electrical and Electronics Engineering Department, Chisholm Institute of TAFE Dandenong Campus


http://www.riaed.net/IMG/pdf/Mini-Grid_Design_Manual-2.pdf

http://www.riaed.net/IMG/pdf/Mini-Grid_Design_Manual-2.pdf

40 |


Introduction

French bean (Phaseolus vulgaris L.) is an important crop in Kenya with high impact on rural employment and livelihood. Amongst the known constraints, pollination has not featured amidst many farmers, a fact associated with lack of knowledge. The crop benefits from bee pollination through improved pod set and pod quality. Very little information exists on the relationships

between bee pollinators and French beans in Kenya. Some empirical researches worldwide have reported that bees increase fruit setting and seed yields of some angiosperms (Klein et al., 2007). However there is no such information on French beans. This crop is a sub species of P. vulgaris, which is planted in Central, Eastern and Western regions of the Country. Majority of the cultivars of French beans are bush type annuals that reach a height of about 2.5 feet. The leaves are

dIURNAL dIvERSITY ANd ACTIvITY dENSITY OF BEES ON FRENChBEAN (PhASEOLUS vULgARIS L.) FLOwERS IN mERU COUNTY,

kENYA

Masiga RDO1,5, Kasina M2*, Mbugi J1, Odhiambo C3, Kinuthia W3, Gemmill-Herren B4 and Vaissière B6

1Kenyatta University, Department of Zoological Sciences, P. O. Box 43844-00100, Nairobi2Kenya Agricultural and Livestock Research Organization, NARL, P.O. Box 14733-00800 Nairobi,

3National Museums of Kenya, P. O. Box 40658-00100, Nairobi,4Plant Production and Protection Division – Agriculture and Consumer Protection Department Food and

Agricultural Organization of the United Nations, Rome 00153 Italy,5Sangalo Institute of Science & Technology, Department of Agriculture, P.O. Box 158- 50 2000

6INRA (Institut National de la RechercheA gronomique), UR 406 Abeilles et Environnement, Centre de Recherche PACA, 228 route de l’Aérodrome, CS40509, Domaine Saint-Paul - Site Agroparc, 84914 Avignon

Cedex 9, France*Correspondence: [email protected]

Abstract

Frenchbean (Phaseolus vulgaris L.) is an important crop in Kenya with high impact on rural employment and livelihood. Amongst the known constraints, pollination has not featured amidst many farmers, a fact associated with lack of knowledge. The crop benefits from bee pollination through improved pod set and pod quality. In this study, bees were observed from morning to evening (06:00h to 18:00h) on hourly basis to determine their diversity and abundance on flowers of French beans in Meru County. Six small scale farms with French beans var. Julie were randomly selected from 50 GPS selected farms, along a transect of 1km from the forest. Three farms were each at 200m, 800m, and 1000m from Mt. Kenya National Reserve forest edge. Sampling was done at the onset of 50% flowering. Results showed presence of Apis mellifera, Megachile spp. and Xylocopa spp. on the flowers. Apis melliferra had the highest visitations with peak visits from 10:00h to 11:00h and 1:00h to 15:00h. Xylocopa spp. visitations peaked from 12:00h to 13:00h while Megachile spp. visits peaked at 14:00h. No visitations were observed between 06:00h – 08:00h and after 17:00h. However, Megachile spp. visitations started past 09:00h and ended at 16:00h. Generally, French beans in farms near the forest recorded higher frequency of visitation compared with those in farms far away from the forest. In addition, Apis mellifera visitation frequency was higher on French beans near the forest while it the reverse for Megachile spp. and Xylocopa spp. The findings show that it is possible to incorporate bee friendly pest and water management plan at blooming stage by utilizing window hours when bees are not expected to be on the crop.

Key words: Pollinators, Xylocopa spp; Apis mellifera; Megachile spp.


| 41


dense, heart-shaped and 3-6 inches long. The fruit is a pod, straight or slightly curved, 4-8 inches long, with a prominent beak. The seeds may be white to red, brown speckled or blue black, globular to oblong and from ¼ to 1 inch long. Pods contain 1-12 seeds. The flower is usually whitish, but may be tinged to deep violet, purple or red and ½ -3/4 inch long. The keel is prolonged in a spirally twisted beak; the style follows the spiral of the keel (Graham et al., 1997; Debouck, 1991).

Green pods of French beans are exported to earn the country foreign exchange (H.C.D.A., 2007). In addition, green pods are sold locally or eaten by the farmers’ family. Rhizobia bacteria in their root nodules improve soil fertility by adding atmospheric nitrogen to the soil. Marketing records in Kenya show that French bean yields are on the decline which may be due to pollination deficit. Pollination deficit may result in poor quality and quantity of pods, which may be due to lack of seeds or abortion of flowers. These are pods which are too small, hard, curved or rotten. These poor quality pods are rejected by the buying companies causing losses to the farmers and the Country as a whole (H.C.D.A., 2006).

The high population in Laikipia County has lead to land fragmentation and agricultural intensification, which research has reported to be the most threats of bee pollinators. Therefore, the study set to assess diurnal visits of bees on flowers of French beans along forest-farm gradient so as to recommend conservation measures.

Materials and methods

The study was conducted in Timau divisions of Meru County in the 2012.The natural habitat was an indigenous forest on North West slopes of Mt Kenya. The area stretches across the equator between latitudes 0°15’S and 0° 45’N and longitudes 36° 11” and 37° 24’ E. The region is on a high altitude plateau ranging from 1600 m to 21400 m above sea level, with an area of 9,723 km2 and bordering the western foot of the Mount Kenya (5,199 meters). It is bordered by Aberdare Ranges on the south-west and the Great Rift Valley escarpment on the west. Topography ranges from lowlands to inselberg hills in the north. The two major rivers Ewaso Ng’iro and Ewaso Narok originate

from Mt. Kenya in the south and flow towards the north. The average annual rainfall ranges between 637mm and 1300mm from the drier north western plateau to the wet slopes of Mount Kenya and the Aberdare Ranges. The place receives bimodal rainfall. Temperatures vary from 20 to 28oC (Jaetzold and Schmidt, 1983).

Two farms were located at 0.2km, 0.8km and 1km from the forest along 1km transect. The growing of the focal crop started in May and extended up to August, under cyclic crop rotation. Flowering started one month after planting and extended for 5 to 6 weeks. The pods were ready for picking two months after planting and the picking continued for a month. Bee sampling was started at onset of 50% of blooming of the crop. Sampling of bee visits on French bean flowers started from 06:00h to 18:00h and recording was done at one hour intervals. Sampling was done for three days per farm in a quadrant measuring 2 m2 using direct observation method.

Shannon diversity index was used to assess species composition of bees.

Results

A total of 351 bee visits were observed in farms which were located 0.2 km, 0.8 km and 1.0 Km away from the forest. The bees observed and indentified on French bean flowers were from the families Apidae (Apis mellifera and Amegilla spp), Melitidae (Xylocopa calens, X. incostans and Ceratina spp), Megachilidae (Megachile rufipes and M. bituberculata), Collitidae (Collete spp), Halictidae (Halictus spp).

The Shannon diversity index (H) showed that at 0.2 km, H was 0.890, 0.673 at 0.8 km, and 0.667 at 1km. This result shows that higher diversity of bee families was recorded at farms located at 0.2 km. Species composition at 0.8km and 1 km were almost the same as there was little difference between the indices. This implies that those two habitats were almost similar.

Based on ANOVA, Apidae family had significantly highest numbers, followed by Melitidae, Megachilidae, Collitidae and Halictidae in that order (F = 4.58, p = 0.028). Thus, the number of bees in the other bee families were not significant compared to those of Apidae (p > 0.05)(Table 1 and Figure 1).


42 |


Table 1: Number of bee families visiting French bean flowers on farms

Farms’ distance from the forest

0.2 km 0.8 km 1.0 km

Bee families counted

Mean ± SE Mean ± SE Mean ± SE

1. Apidae 21.33 ± 3.44b 11.67 ± 2.60a 10.33 ± 2.33a2. Mellitidae 2.33 ± 1.05a 5.00 ± 1.15a 3.00 ± 1.21a3. Megachilidae 0.33 ± 0.33a 0.50 ± 0.34a 1.33 ± 0.49a4. Collitidae 0.17 ± 0.17a 0.17 ± 0.17a 0.33 ± 0.21a5. Halictidae 0.00 ± 0.00a 0.00 ± 0.00a 0.33 ± 0.33a

Mean values in similar rows denoted by similar letters are not significantly different at 95%CI

0 2.5 5

7.5 10

12.5 15

17.5 20

22.5 25

27.5

0.2 km 0.8 km 1.0 km Farm distance from the forest

Apidae Mellitidae Megachilidae Collitidae Halictidae

No. of bee in the family

Figure 1: Number of bees in the families sampled from the farmsDiurnal species diversity was calculated and the results are shown in the Table 2. A significantly higher number of A. mellifera were recorded on farms located at 0.2 km compared with farms which were located at 0.8 and 1km from the forest (F = 5.90, p = 0.013). All the other bee species were not significantly different in the farms at various distances from the forest (p > 0.05).

Based on single factor ANOVA, time of the day significantly (p < 0.05) affected diversity and abundance of bees visiting French bean flowers since the p value and F-critical value were both 0 (df = 29). The earliest visitation of all the three bee species started from 8:00h and the latest visitation was at 18:00 h. Therefore, there was no foraging between 18:00 h to 8:00h. A. mellifera foraged from 8:00h to 17:00h; the peak visitation rates were between 10:30h to 14:00h. However, A. mellifera lowest visitation rates were between 16.00h to 17:00h. Xylocopa spp foraged from 9:00h to 16:00h; the peak visitation rates were between 12:00h to 14:00h, and lowest visitation rates were at 17:00h. Generally, leaf cutter bees foraged from 9:00h to 16:00h. The peak

visitation rates were between 12:30h to 15:00h and lowest visitation rates were between 10:30 and 11:30h, where visits drop to zero.

Table 2: Number of bee species visiting French bean flowers on the farms

Farms’ distant from the forest

0.2 km 0.8 km 1.0 km

Bee species counted

Mean ± SE Mean ± SE Mean ± SE

1 Apis mellifera 20.83 ± 3.44a 11.33 ± 2.29ab 9.67 ± 1.17b

2 Amegilla 0.50 ± 0.34a 0.33 ± 0.33a 0.83 ± 0.65a

3 X. caren 1.50 ± 0.72a 1.67 ± 0.76a 1.67 ± 0.80a

4 X. flavorufa 0.50 ± 0.34a 2.83 ± 0.87b 0.83 ± 0.40ab

5 Ceratina 0.17 ± 0.17a 0.33 ± 0.21a 0.33 ± 0.21a

6 M. bituberculat 0.17 ± 0.17a 0.17 ± 0.17a 0.83 ± 0.40a

7 M. rufipes 0.17 ± 0.17a 0.33 ± 0.33a 0.50 ± 0.22a

8 Halictus spp 0.00 ± 0.00a 0.00 ± 0.00a 0.33 ± 0.33a

9 Collete 0.17 ± 0.17a 0.17 ± 0.17a 0.33 ± 0.21a

10 Lasioglosum 0.00 ± 0.00a 0.00 ± 0.00a 0.00 ± 0.00a

11 Melliponula 0.00 ± 0.00a 0.00 ± 0.00a 0.00 ± 0.00a


| 43


Means denoted by similar letters in the same row is not significantly different at 95% CI


Farms which were at 0.2 km had significantly higher species composition compared farms at 0.8 and 1km from the forest. According to island theory of Robert M.H. (1967) and many other empirical researches, the forest is a reservoir of all bee species and also provides foraging resources and nesting sites to the bees (Klein et al., 2002a; Baszanak, 1992) in contrast to fragmented annually ploughed fields with fewer non-crop habitats. Farms at 0.8 and 1km from the forest had almost similar diversity composition. Probably the biotic and abiotic factors were similar. Higher abundance of solitary bees at 0.8 and 1km from the forest was attributed to the presence of sunny, open conditions and preferred weeds on further farms compared to near farms to the forest (Klein et al., 2003; Taylor et al., 2004).

The significantly higher abundance of A. mellifera at 0.2km compared to 0.8 and 1km from the forest was attributed to the forest having mature indigenous trees which provided them with nesting sites (Klein et al., 200). The significantly higher visitation rates of A. mellifera were attributed to its high fecundity rate, aggressiveness, and also some farmers practicing apiculture (Kremen et al., 2004).

All the three species were absent between 17:00h to 08:00h, because the flowers had no or less nectar and pollen grains and temperature was low and the leaves of French beans were covered with dew. The peak

activity of all bees on flowers of P. vulgaris was located between 10:00h and 13:00h, which correlated with the warm to hot period (Kingha et al., 2012). Bee foragers prefer warm or sunny days for good floral activity (Kasper et al., 2008; Kevan in 2001; Doug, 2002).

A. mellifera foraged on flowers of French beans from 08:00h to 17:00h, with a peak activity between 10:30h to 14:00 h. However, Chantal et al. (2013) reported the peak activity of A. m. adansonii on P. vulgaris flowers (Fabaceae) to be between 7:00 h and 8:00 h. Visitation rates were low during early morning due to very low temperatures on the slopes of Mt. Kenya. Similarly visitation rates dropped between 11:30h and 13.00h due to very high temperatures (Chantal et al., 2013).

Xylocopa spp and Megachile spp foraged on French bean flowers from 9:00h to 16:00h. The peak activity for Xylocopa spp was between 12:00h to 14:00h while that of Megachile spp was 12:30h to 15:00h. However, the empirical study by Kingha et al. (2013) reported the peak activity of X. calens on P. vulgaris (Fabaceae) flowers to be between 10:00h and 13:00h. Similarly the decrease in visitation rates from 14:00h (Xylocopa spp.) and 15:00h (Megachile spp.) was due to decreased temperatures and presence of dew on leaves of French beans. The decrease in visitation rates of these solitary bees between 09:30h to 11:00h was attributed to high abundance of aggressive and abundant A. mellifera, as it was the time it reached the highest peak.

In conclusion, the findings show that it is possible to incorporate bee friendly pest and water management plan at blooming stage by utilizing window hours when bees are not expected to be on the crop.


44 |


References

Banaszaka L (1992). Strategy for conservation of wild bees in an agricultural landscape, Agriculture, ecosystem and environmental 40, 179-192

Doug S (2002). Honey bees in faba bean pollination. Agote DAI-128. Revised March 2002. Goulburn.

Bernice MTK, Fernand-Nestor TF, Albert N and Dorothea B (2012) Foraging and pollination activities of Xylocopaolivacea on Phaseolus vulgaris (Fabaceae), Cameroon). Journal of Agricultural Extension and Rural Development Vol. 4(6), pp. 330-339, 6 June, 2012.

Chantal D and Fernand-Nestor TF (2013) Foraging and pollination behavior of Apismelliferaadansonii L. on Phaseolus vulgaris (Fabaceae), Cameroon. International Research Journal of Plant Science (ISSN: 2141-5447) Vol. 4(2) pp. 45-54, February, 2013.

Debouck D (1991). Systematics and morphology. In: Common beans: research for crop improvement, Van Schoonhoven, A and Voyset, O (eds), Cali, Colombie. pp 55-118.

Graham PH, Ranalli P (1997). Common bean ( Phaseolus vulgaris L.). Field Crop Res., 53: 131-146.

Horticultural Crops Development Authority (2007). HCDA Export statistics values of 2006

Horticultural Crops Development Authority (2008). HCDA Export statistics values of 2007

Kevan PG (2001). Pollination: A Plinth, Pedestal, and Pillar for Terrestrial Productivity. The Why, How, and Where of Pollination Protestion, conservation and Promotion. Entomological Society of America Proceedings from Bees and Crop pollination-Crisis, Crossroads, Conservation: 7- 68. Klein AM, Buchori D, Steffan DI, and Tscharntke T (2002a).

Effects of land use intensity in tropical agroforestry systems on flower-visiting and trap-nesting bees and wasps. Conservation Biology, 16, 1003-1014. Klein AM, Vaissire BE, Cane JH, Steffan I, Cunningham SA,

Kremen C and Tscharntke T (2007). Importance of pollinators in changing landscapes for world crops, Proceedings of the Royal Society of London:-274:303-313.

Kremen C, Williams NM and Thorp RW (2004). Crop pollination from native bees at risk from agricultural intensification, Proceedings of the National Academy of Science, U.S.A. 99, 16812–16816.

Kremen C, Williams NM, Bugg RI, Fay JP and Thorp RW (2004). The area requirements of an Ecosystem services: Crop pollination by native bee communities in California, Ecology Letter. 7, 1109-1119.

Taylor H, Rickets Gretchen CD, Ehrlic PR, and Michener CD (2004). Economic value of tropical forest to coffee production, Conservation science program, world wildlife fund, 1250, 2004 by the National academy of science of the USA. PNA/Augast 24, 2004/vol. no. 34/ 12579-12582.


| 45


COmPETENCE PROFILINg FOR LOANS OFFICERS IN ThE BANkINg SECTOR IN SUB-SAhARAN AFRICA: A CASE OF UgANdA

*1Francis Kasekende,1John C. Munene1Makerere University Business School, Kampala, Uganda

Abstract

This paper examined the operant competences for bank loans officers in a Sub-Saharan context and provided policy input required in solving the daunting problem of the existing low levels and high failure rate of collecting loans disbursed to customers. Data were collected from a sample of 319 employees in the banking sector from Kampala district which was specifically chosen for this study. Appropriate analytical data tools were applied. Results reveal the presence of loan and client projections, client preparation and training, loan portfolio supervision and; mobilization and recruitment as operant competence factors that affect the performance of loans officers in the banking industry in Uganda. These findings and their policy implications are fully discussed in the paper. The research findings theoretically conceptualize employee competences from the objectivist perspective which assumes that there is an objective number of competences which an organization or a profession requires to meet its objectives and once this set has been identified, then every unit in the organization and profession works towards acquiring that set; to a new and contemporary constructivist view that allows users of the concept to define competence from their own environment. The study presents the importance of understanding these operant competences. There is a dearth of literature in addressing operant competences for bank loans officers from a Sub-Saharan context; creating a need to study and systematically document the prevailing supporting operant competences for loans officers in order to promote the banking sector in Uganda.

Key words: Operant, Banking Sector, Loans Officer, Client, Mobilization, Training, Uganda.

Introduction

This study aimed at examining the key competences a credit / loans officer should possess in order to handle credit management. The concept of competences is important because employees with high level competences are reported to have a higher level of psychological ownership (Chi & Tzu, 2008), and organizational commitment (Cohen-Charash & Spector, 2001; Colquitt, 2001; Konosvky &Pugh; 1994; Pillai Schrieheim& Williams 1999), organizational citizenship behavior (Kasekende, 2006, Mugabi, 2005). The change from the traditional-job based role that characterized the mass-production economy that dominated Europe during the 20th Century to competence-based role has taken precedence due to rapid developments in computing, information technology and the global economy that have combined to change business competition as well as the type of work which is done (Doyle, 1990; Mugabi, 2005).

The globalization of competition has had a major impact on the level of performance that organizations

have to demonstrate in order to be successful (Lawler, 1994). One major consequence of the new performance demands that organizations face the idea of organizational capabilities founded on individual roles as a basis for competition. While competence-based approach is easy to state at face value, it requires knowledgeable people to both implement and manage the programme (Cameron & Pierce, 1994; Simpson, Fletcher & Campbell, 2000). A competence based approach leads to the development of competence frameworks or profiles that benefit the job holders in enabling them understand clearly what is required to perform effectively in a particular role as well as in wider context. These profiles can promote self-development and they provide a framework for developing tools and techniques to further performance.

A review of extant literature reveals that the term competence has no widely or universally acceptable definition. Jubb and Row-botham (1997) suggested that the purpose of defining competences was to improve human performance. Hoffman (2011) showed three main positions taken towards the definition of the term.


46 |


First, was the position taken by Boam and Sparrow (1992) and Bowden and Masters (1993) who defined competence as observable performance. The second position defined competence as the standard or quality of the outcome of a person’s performance (Rutherford, 1995; Hagger & Chatzisarantis, 2008). Third is the position based on the works of Boyatzis (1982) and Steernberg and Kolligian (1990) who argued that competences are the underlying attributes of a person.

The first position focused on the output or tasks to be completed. According to the works of Hoffman (2011), the organizational outcome was to train and accredit staff by establishing clear and measurable performances for assessment and such performance was concerned with whether they are competent as described in the written standards. Individual competences were described as competences to be performed, observed and assessed for the individual to achieve accreditation as competent. By making the outcomes clear to both the assessor and the learner, it would then enhance competent performance.

The second position defined competence as a standard or quality of outcome and these could be broadened depending on the application of the standard (Hoffman & Henn, 2008). According to Hoffman, a standard could refer to minimum level of performance or a higher level of performance than had previously existed. This could be used to manage change by setting competency standards by which the new work relationships introduced and the change process could be assessed. Also this position was used to refer to standardized performance across part of the company.

The third position defined competence as the underlying attribute of a person such as knowledge, skills and abilities. The focus of this position revolves around the inputs required by the individuals to enable them to produce competent performance. It emphasized what individuals need to know or what skills or other attributes they need in order to perform their work at a competent level. This definition differs from the previous two which are result oriented because it is input oriented. This third position forms the basis of this study in the banking sector in Uganda.

The banking sector is one of the most productive areas in the economy of Uganda. However, it has been characterized by challenges of the loans section. For example during 2013, Bank of Uganda (BOU) conducted on-site examinations of all the licensed commercial banks. The examination approaches were tailored to the institutions’ specific risk profiles

and financial condition. The on-site examinations established that the banking sector is stable. The commercial banks demonstrated improved risk management practices. According to the report, the banking industry remained sound during 2013. Commercial banks remained well capitalized with the ratio of core capital to risk-weighted assets increasing from 18.8 percent in 2012 to 19.9 percent in 2013, well above the regulatory minimum of 8 percent

However, credit and operational risks remained to be the major risks of supervisory concern. The high credit risk exposure is attributed to the after-effects of high credit growth, the economic slowdown in 2011 and 2012, and the high interest rate regime which continued to negatively impact on the quality of the sector’s loan portfolio as evidenced by a deterioration in the ratio of non-performing assets to total advances from 4.2 percent registered in 2012 to 5.6 percent in December 2013. This affected bank profitability which declined to Ushs.414 billion in 2013 from Ushs.544.8 billion in 2012, reflecting the increase in provisions for non-performing loans. (Bank of Uganda Annual Supervision Report, December 2013, Issue No. 4). Operational risk is mainly driven by technological challenges as banks strive to make unique product offerings which are not adequately supported by the existing core banking systems thus necessitating system up-grades and employee capacity building(Bank of Uganda Annual Supervision Report, December 2013, Issue No. 4).

The competence construct was popularized in management literature by researchers from McBer Company such as McClleland, (1973), Boyatzis (1982) and Spencer and Spencer (1993). They defined the term to mean an underlying characteristic of a person resulting in “effective and /or superior performance in a job” (Boyatzis, 1982, p. 6). Whereas scholars do not agree on the precise definition of competences, there appears to be broad consensus that it involves knowledge, skills and attitudes that are required to perform a job competently (Sanghi, 2007; Lucia &Lepsinger, 1999). Extant literature indicates that, practitioners and academicians who have examined competences have done so from the perspective of the objectivist tradition (Heinsman, de Hoogh, Koopman, & van Muijen (2007).

The objectivist perspective assumes that there is an objective number of competences which an organization or a profession requires to meet its objectives and once this set has been identified then every unit in the organization and profession works towards


| 47


acquiring that set. However, Stoof, Martens, Van-Merrienboer and Bastiaens(2002) assert that a search for the one single true set of competences is hindering a creative use of the concept as efforts are geared towards finding and defending the one true set and its definition. This personal approach to competences in general, is tacit, complex and ambiguous. It obscures the relationship between input and output and raises the survival threshold of organizations such as banks in Africa. Stoof,Martens,Van-Merrienboer& Bastiaens (2002) propose instead, to embrace a constructivist view of competence which allows users of the concept to define competence from their own environment. In essence this calls for the use of operant competences.

To remove the ambiguity and to lower the survival threshold of organizations including banks in Africa, the authors are proposing to develop and utilize the operant competences that focus on the relationship between the external work environment and the individual loans officer. According to the authors of this paper, operant competence is defined as a competence that directly influences the work environment and contains its own reinforcements. When a loans officer in the bank meets or exceeds performance objectives he/she influences his/her working environment in at least two ways. One, it creates a situation of anticipation of a response from the manager or colleagues because the behaviour is observable. Two, irrespective of the expected response from one’s superior or colleagues (the environment), the act itself is positively reinforcing because its impact on other aspects of the observable to the performer (for instance, acquisition of self-determination, confidence, meaning to the loans officer). Such clear outcomes can inspire the loans officer to be more productive and exceed his/her job expectations. Significantly from the point of view of this work, the operant competence approach to bank loans officer competences articulates bank loans officers’ practices that make a difference under a given environment. However, there seems to be a dearth of literature on the factors that measure the concept of operant competences for loans officers in the banking sector in Sub Saharan Africa.

Some of the literature that examined the concept of operant competences focused on engineering lecturers’ operant competences (Kagaari & Munene, 2007)and summarized it under seven key results areas (KRAs) (Armstrong & Baron, 1995) or competences (Richey, Fields &Foxon, 2001).Under each KRA the study outlined more specific behavioural competences addressing two questions namely what you need to

know and what you need to be able to do to fulfil each KRA. The overall outcome was a list of specific action oriented performance statements referred to as operant competences that could easily be measured. Mugabi (2005) examined the relationship between competences of micro finance loans officers and organizational citizenship behavior; but fell short of specifying the actual factors that underlie the operant competences of a micro-finance loans officer. Kasekende (2006) examined the competences of primary school teachers and found them to be positively correlated to organizational commitment and organizational citizenship behavior. Given the trend of poor performance of the loans portfolio in the commercial banking sector (see table 1), it is necessary to therefore identify the appropriate operant competences a loans officer should possess. However, there is a dearth of literature on the concept of operant competences in this sector. This study therefore intends to bridge this gap by investigating factors relevant for effective operant competences of loans officers in the banking sector in Uganda.

Material and Methods

Research design

This study adopted a cross-sectional descriptive and analytical research design, examining operant competences for loans officers in the banking sector. In order for the researcher to answer the hypothesis developed in the literature review, the authors undertook a large scale comprehensive survey. The survey covered a random sample of banking institutions from Kampala district. This study covered Kampala district because it is the hub of banking activities in the whole country. Each of the commercial banks has a branch in Kampala making it the best area for this study. The authors used the population estimates of employees working in banks in Kampala based on documentation for the 1st quarter of the financial year 2014 as provided by Bank of Uganda. The banking sector in Kampala district alone had a population of 4430.

Population, sample size and sampling procedure

The study population was comprised of 4430 bank employees consistent with database documentation from Bank of Uganda (2014). In this study we sought 95% confidence level and computed a sample size of 354 employees based on Krejcie and Morgan (1970)


48 |


sample size determination table. Lists of employees in the various banks were used to form the sampling frame.

A simple random sampling technique using a table of random numbers was used to pick the required number of employees in each bank. All employees were listed in alphabetical order and given identification numbers chronologically. The selection criterion was based on the length of the largest numbers on the population list. We selected digits in groups of two, three, and four for the numbers that were in tens, hundreds and thousands respectively. Selection was done only to those cases from the list for the sample which corresponded with the identified numbers. Using this process the authors ignored all repeated numbers and numbers that were not on the population list. We continued this process until we arrived at the required sample size of 354. The questionnaire was pilot tested in Wakiso district. All ambiguously stated and seemingly difficult questions were either revised or totally deleted from the questionnaire before conducting the final survey. Data were collected from employees in various banks in Kampala district. Kampala was chosen because of its significance as a hub for banking activities in Uganda where the industry is performing poorly in the loans portfolio.

Data collection instrument and measurement of variables

The study utilized a questionnaire to collect data from respondents. This questionnaire had fixed response questions. The measurement items were derived from previous published studies adapted and tested for validity and reliability. Chronbach alpha co-efficient for the construct was 0.94 well above the 0.7 requirement (Nunnally, 1978).In operationalizing operant competences we adopted the Partners in Learning and Action (PILA) item measures developed by Munene (2003) and modified them to suit the context of the study. This was done because the tool had been tested and used in earlier studies in similar settings; also it had been tested for validity and reliability. The tool was anchored ona 5 pointlikert scale. The scale ranged from “Strongly agree” =5(very high) with a mean range of 4.20 to 5; “Agree” =4(high) with a mean range of3.40 to 4.19; “Not sure”=3(average) with a men range of 2.60 to 3.39; “Disagree”=2(low) with a mean range of1.80 to 2.59and “Strongly disagree”=1(very low) with a mean range of 1.00 to 1.79. According to Sanghi (2007), competences involve knowledge, skills and attitudes that are required to perform a job competently.

Results

The response rate for the main survey was 90.1%. In this paper, the results were based on 319 respondents. In terms of job level the results show that 1.6% of the respondents were supervisors, 19.7% were senior officers and 78.7% junior officers. In terms of gender, male respondents accounted for 59.9% while female respondents accounted for 40.1%. This indicates a relatively even distribution of respondents showing that we were able to obtain information about operant competences from the employees in banks regardless of sex differences. In terms of level of education, respondents with first degrees accounted for the biggest percentage (75.95%) a figure above half way the total number of respondents. Those with postgraduate diplomas accounted for 11.3% while diploma holders were 12.8%. The overall results indicate that the respondents were educated enough to read, comprehend and provide appropriate responses to the required questionnaire items. In terms of period spent in the working place, results showed that 49.8% had worked in their current workplaces for between 2-4 years; 24.1% for 1-2 years, 19.1% for more than 4 years 6.3% for less than a year and 0.6% for 3 years. In terms of marital status, 61.1% were married while 38.9% were single (Table 1).

Table 1: Descriptive statistics

Frequency % Cumulative %

Job grade Supervisor 5 1.6 1.6Senior officer

63 19.7 21.3

Junior officer

251 78.7 100.0

Sex of respondent

Male 191 59.9 59.9

Female 128 40.1 100.0Marital status

Single 124 38.9 38.6

Married 195 61.1 100.0Age of respondent

20-29 141 44.2 44.2

30-39 171 53.6 97.840-49 7 2.2 100.0

Highest level of education

Diploma 41 12.8 12.8

Degree 242 75.9 88.7Post graduate qualification

36 11.3 100.0


| 49


Frequency % Cumulative %

Time worked in the organization

Less than a year

20 6.3 6.3

1-2 years 77 24.1 30.43 years 2 .6 31.02-4 years 159 49.8 80.9More than 4 yrs

61 19.1 100.0

Using principal component analysis as an extraction method to explore the factor structure of operant

competences for loans officers in Uganda, an exploratory factor analysis was run. Varimax rotation method with Kaisor-normalization was used. It was necessary to carry out factor analysis in order to interpret, understand and describe the data in a much smaller number of concepts than the original individual variables (Hair, Anderson &Tatham., 2006). Kaisor-Meyer-Olkin measure of sampling adequacy and Bartlett’s test of sphericity were run where it was established that our data was suitable for analysis. These revealed a co-efficient of 0.91, with an approximate X2

of 4328.26, degrees of freedom 253 and significance ≤0.001 (Table 2).


Tab

le 2

: Fac

tor

anal

ysis

for

com

pete

nces

of

a lo

ans

offi

cer

Com

pone

nt

Loa

n &

cl

ient

pr

ojec

tion

s

Clie

nt

prep

arat

ion

&

trai

ning

Loa

n po

rtfo

lio

supe

rvis

ion

Mob

iliza

tion

&

rec

ruit

men

tL

oan

reco

ncili

atio

nK

MO

Bar

tlett

s te

stdf

Sign

CO

MP1

3_1

Inpu

t cus

tom

er in

form

atio

n in

to th

e co

mpu

ter s

yste

m.8

20.

9143

28.2

625

30.

00

CO

MP1

4_1

Proc

ess

cust

omer

dat

a co

llect

ed.7

9

CO

MP1

2_1

Col

lect

dat

a ab

out t

he c

usto

mer

s h

ouse

hold

and

the

busi

ness

.78

CO

MP1

0_1

Get

pro

perly

fille

d lo

an a

pplic

atio

ns fr

om th

e cu

stom

ers

.77

CO

MP1

7_1

Ver

ify lo

an s

ecur

ity d

ocum

ents

.73

CO

MP1

1_1

Con

duct

bus

ines

s en

viro

nmen

t ana

lysi

s.7

3

CO

MP1

5_1

Inve

stig

ate

the

cons

ent o

f th

e ho

useh

old

to th

e bo

rrow

ing

plan

.71

CO

MP2

3_1

Prep

are

loan

cas

es th

at re

quire

furt

her a

ppro

val

.79

CO

MP2

1_1

Prov

ide

feed

back

for t

he c

usto

mer

s /l

oan

appl

ican

ts.7

7

CO

MP2

0_1

Mak

e bu

sine

ss c

ase

for t

he lo

an a

pplic

atio

n.7

3

CO

MP2

4_1

Dra

w lo

an re

paym

ent p

lan

for p

rese

ntat

ion

to th

e lo

an c

omm

ittee

.70

CO

MP2

5_1

Follo

w u

p cu

stom

ers

to c

ompl

ete

loan

doc

umen

tatio

n.6

9

CO

MP1

8_1

Gen

erat

e lo

an f

act s

heet

.64

CO

MP5

3_1

Rev

iew

cus

tom

er lo

an p

aym

ent h

isto

ry.8

8

CO

MP5

2_1

Rev

iew

bus

ines

s en

viro

nmen

t and

impa

ct o

n lo

an p

erfo

rman

ce.8

7

CO

MP5

4_1

Mak

e pe

riodi

c lo

an re

cove

ry re

port

to th

e br

anch

man

agem

ent

.73

CO

MP4

7_1

Gen

erat

e da

ily a

nd m

onth

ly lo

an a

rrea

r rep

orts

.69

CO

MP5

0_1

Vis

it th

e cu

stom

er to

dis

cuss

reco

very

pla

n.6

8

CO

MP2

6_1

Ana

lyse

and

und

erst

and

the

term

s an

d co

nditi

ons

of th

e ap

prov

ed

loan

.86

CO

MP2

9_1

Com

mun

icat

e to

the

cust

omer

the

term

s an

d co

nditi

ons

of th

e lo

an.8

4

CO

MP2

7_1

Gen

erat

e do

cum

enta

tion

chec

klis

t for

loan

dis

burs

emen

t pro

cess

.73

CO

MP3

9_1

Rec

onci

le in

form

atio

n ca

ptur

ed in

the

com

pute

r sys

tem

with

in

form

atio

n in

cus

tom

ers’

loan

file

.83

CO

MP4

1_1

Rev

iew

term

s an

d co

nditi

ons

of th

e lo

ans

disb

urse

d.7

9

Tot

alT

otal

4.71

3.72

3.53

2.20

1.58

Eig

en v

alue

Eig

en v

alue

20.4

716

.18

15.3

69.

576.

86

Cum

ulat

ive

%C

umul

ativ

e %

20.4

736

.65

52.0

161

.58

68.4

6

Ext

racti

on M

ethod

: Prin

cipal

Com

pone

nt A

nalys

is.

Rot

ation

Meth

od: V

arim

ax w

ith K

aiser

Nor

mal

izat

ion


| 51


The results reveal that the data were fit for factoranalysis and that the relationships among variables are significant. All measurement items had communalities above 0.60. The exploratory factor analysis produced five factors of Loan & client projections (20.47%), Client preparation & training (16.18%), Loan portfolio supervision (15.36%), Mobilization & recruitment (9.57%) and Loan reconciliation (6.86%) which overall explained 68.46% of the variance in operant competences of a loans officer.

The confirmatory factor analysis (CFA)was then run to confirm the dimensions and test the fit of the theoretically grounded model of banks to data (Joreskog and Sorbom, 1989) (Figure 1). CFA for the model was investigated using Amos version 18. Since our data were normally distributed, CFA was assessed using maximum likelihood estimation. This was done through the establishment of several competing rival models to be fit to the data (Hair et al., 2006). CFA allowed data reduction and to construct meaning to banks through operant competence profiling. Consistent with Schermelleh-Engel et al., (2003), results revealed an acceptable model fit of X2/df if 1.38 which was < 3 (Hair et al., 2006). The root mean square error of approximation was 0.04 compared against the recommended standard ratio of 0.08 (Table 3).

Compared to the recommended standard cutoff point of 0.95, the Tucker Lewis index was 0.99, the

Comparative fit index was 0.99, the Normed fit index was0.96 and the Goodness of fit index was 0.97. Lastly, in comparison with the recommended 0.90 cutoff point, the Adjusted goodness of fit index was 0.95 (Figure 1 and Table 3).This implies that the model fit our data acceptably.

Table 3: Model fit

X2 df p X2/df GFI AGFI TLI NFI CFI RMSEA AVE

Cut off point ≤ 2* ≤0.05 ≤ 3 ≥0.95 ≥0.90 ≥0.95 ≥0.95 ≥0.95 ≤0.05 ≥0.5

Estimated model 66.35 48 0.19 1.38 0.97 0.95 0.99 0.96 0.99 0.04 0.61

As observed earlier in the model in Figure 1, the operant competency construct yielded four factors namely loan and client projections, client preparation and training,

loan portfolio supervision and; mobilization and recruitment. The details of these are found in Table 4.


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Table4: Path coefficients for the measurement model

Unstandardized coefficients

S.E. C.R. P Label Standardized coefficients

COMP13_1 <--- Loan & client projections 1.00 .87

COMP14_1 <--- Loan & client projections 1.00 .05 18.67 *** par_1 .83

COMP12_1 <--- Loan & client projections .93 .05 18.15 *** par_2 .82



COMP18_1 <--- Client preparation &training 1.00 .74

COMP24_1 <--- Client preparation & training 1.15 .10 11.31 *** par_5 .74

COMP20_1 <--- Client preparation & training 1.24 .10 11.94 *** par_6 .76

COMP54_1 <--- Loan portfolio supervision 1.00 .77

COMP52_1 <--- Loan portfolio supervision 1.07 .13 8.18 *** par_7 .76

COMP29_1 <--- Mobilization & recruitment 1.02 .16 6.54 *** par_8 .86

COMP26_1 <--- Mobilization & recruitment 1.00 .75

The summary statistic in Table 5 indicates the presence of loan and client projection competence for loans officers in the banking sector in Uganda (Mean=3.78, SD=0.64). Operant competences were defined as individual possession of knowledge, skills and attitudes that are required to perform a job competently. Results revealed that among employees in the banking sector there is an opinion that they possess ability to project the level of loan requests from clients. The employees underscored the importance of being able to foretell how many clients are likely to take a loan and what amount. Employees in the banking sector believe that they have the skill to input customer information into the computer system (Mean=3.79, SD=0.77), thus project loan and client numbers. This finding is true because it is supported by the results in Table 4where loan and client projection explain 87% of the variance in inputting customer information into the computer system. The employees in this sector also opined that indeed they have the knowledge and capability to process the data they collect from customers (Mean=3.73, SD=0.81) further strengthening the view that during this processing of data they are dealing with loan and client projections. CFA results in Table 4attest to this effect where loan and client projection account for a significant part in processing of data collected from customers (r2=0.83, CR=18.67, SE=0.05). The ability of the employees to also get properly filled loan applications from the customers (Mean=3.85,

SD=0.76) (Table 5) is indicative of loans officers’ competence in loan and client projection. From the CFA results in Table 4 one can infer that indeed client and loan projection account for a substantial part of collecting data about the customers household and the business (r2=0.82, CR=18.15, SE=0.05). This implies that if a loans manager can competently enable a client fill his or her loan application form, enter the information, then he/she has a loan/client projection competence. The employees in the banking sector further opined that they have the ability to conduct business environment analysis (Mean=3.80, SD=0.74) (Table 5) implying that by doing so, they are exhibiting a high level of loan client projection for the bank. This is supported by CFA findings in Table 4,where client and loan projection explain a big percentage of the loans officers ability to conduct business environment analysis (r2=0.78, CR=16.64, SE=0.05).

The above discussions have policy and managerial implications for the private sector especially the banking industry. Employers need to establish the factors that lead to loans officers develop the ability or competence to project loan and client base for the institution. Managers in the banking sector too, need to set human resource policies especially performance and appraisal policies based on loan client projection competences in the individuals; meaning that employee performance can be measured based on their ability to effectively and competently project loan/client base.


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Client preparation and training

Content analysis revealed the presence of client preparation and training competence for bank loans officers (Mean=3.65, SD=0.59) (Table 5). Client preparation and training was defined as the process of ensuring that the client seeking for a loan has enough knowledge of the details for the loan he/she is applying for. Loans officers take initiative to sensitize the clients over this issue. These results reveal that employees in the banking sector opine the ability to prepare and train loan clients as a competence. The employees draw attention to the importance of preparing and sensitizing clients on the details of the loan they are about to take. This study reveals that employees in the banking sector believe that the ability to make clients’ business cases for the loan application (Mean=3.55, SD=0.76) (Table 5) translates into a preparation and training competence. The CFA results in Table 4further cement this finding when client preparation and training account for a reasonable percentage of the variance in loans officers’ ability to make clients’ business cases for the loan application (74%). Also when loans officers competently draw loan repayment plan for presentation to the loan committee (Mean=3.81, SD=0.73) (Table 4), they are exhibiting a preparation and training competence. In Table 4, CFA results attest to the effect when client

preparation and training accounts for a sizable variance in loans officers competently drawing loan repayment plan for presentation to the loan committee (r2=0.74, CR=11.31, SE=0.10). In other words, the employees in the banking sector assume that once a loans officer has gained the skill and knowledge of properly presenting a loan repayment plan to a loans committee or his/her manager, then such employee boasts of a preparation and training competence. Lastly this study revealed that the preparation and training competence can be established when a loans officer is able to generate aloan fact sheet (Mean=3.60, SD=0.64).This finding is further supported by CFA results in Table 4which indicate that a good part of the loans officer’s ability to generate a loan fact sheet is explained by client preparation and training (r2=0.76, CR=11.94, SE=0.10). The policy and managerial implications based on the above deliberations include the necessity for management to establish the factors that enable loans officers develop the ability or competence to prepare and train clients seeking to attain loans. Managers can ably promote this competence by establishing training related policies. Also, during performance appraisal, employees can be appraised based on the client preparation and training competences; meaning that employee performance can be measured based on their ability to effectively and competently sensitize a loan client.

Table 5:Variable descriptive and descriptive statistics

n Min Max Mean SD (σ) αLoan & client projections

Input customer information into the computer system 319 1 5 3.79 .77

Process customer data collected 319 1 5 3.73 .81

Collect data about the customers household and the business 319 1 5 3.74 .76

Get properly filled loan applications from the customers 319 1 5 3.85 .76

Conduct business environment analysis 319 1 5 3.80 .74Summary item statistic 319 1 5 3.78 .64Loan portfolio supervisionMake periodic loan recovery report to the branch management 319 1 5 1.76 .68Review business environment and impact on loan performance 319 1 5 1.69 .74Summary item statistic 319 1 5 1.72 .63Mobilization & recruitmentAnalyse and understand the terms and conditions of the approval loan 319 1 5 3.40 .55Communicate to the customer the terms and conditions of the loan 319 1 5 3.28 .48

Summary item statistic 319 1 5 3.34 .47

Client preparation & trainingMake business case for the loan application 319 1 5 3.55 .76Draw loan repayment plan for presentation to the loan committee 319 1 5 3.81 .73Generate loan fact sheet 319 1 5 3.60 .64Summary item statistic 319 1 5 3.65 .59


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Mobilization and recruitment

The study also revealed that mobilization and recruitment of clients is a key competence for bank loans officers (Mean=3.34, SD=0.47) (Table 6). Client mobilization and recruitment refers to the enlisting of genuine and potential clients to attain loans from the bank. These results reveal that employees in the banking sector view the ability to mobilize and recruit loan customers for the bank as a competence. The employees draw attention to the importance of mobilizing and recruiting genuine clients for a loan facility. This study reveals that employees in the banking sector believe that the ability of loans officers to competently analyze and understand the terms and conditions of the loan approval (Mean=3.40, SD=0.55) (Table 5) depict a mobilization and recruitment competence. The results from CFA in Table 5, demonstrate that a big percentage of the loan officers’ ability to analyze and understand the terms and conditions of the loan approval is explained by mobilization and recruitment (r2=0.86, CR=6.54, SE=0.16). This seems to imply that when the loans officer picks a genuine client, the bank will not lose its money through client failure to pay back, but it will gain through the interest paid by the client. Furthermore, the concept of employee mobilization and recruitment competence is exhibited when the loans officer appropriately communicates to the customer the terms and conditions of the loan (Mean=3.28, SD=0.48) (Table 5). From the CFA results we can infer that a good percentage of communicating to the customer the terms and conditions of the loan is explained by mobilization and recruitment (75%) (Table 4). Managerial and policy implications based on the above deliberations include the necessity for management to establish the aspects that act as precursors to the acquisition of mobilization and recruitment skills. Managers can ably promote mobilization and recruitment competence by establishing this concept in the performance management of loans officers. During performance appraisal, employees can be assessed based on how well they ably exhibited their mobilization and recruitment competences.

Loan portfolio supervision

Lastly, content analysis revealed the absence of the loan portfolio supervision competence for bank loans officers (Mean=1.72, SD=0.63) (Table 5).Loan portfolio supervision was defined as the act of managing

an assortment of client and client information to whom loans have been extended and deciding whether they are performing well or not and what action to take. In this study, loans officers perceived that the appropriate supervision of the range of clients to whom loan facilities were extended to be a competence that is lacking in the banking sector. Employees in the banking sector opine that there are low levels of the ability to make periodic loan recovery report to the branch management (Mean=1.76, SD=0.68) (Table 5) hence translating into poor loan portfolio supervision competence. This finding is inconsistent with CFA results in Table 4which confirmed that indeed a sizable percentage of the loans’ officers’ ability to make periodic loan recovery report is explained by loan portfolio supervision (77%) (Table 4). What this means is that much as one of the operant competences loans officers should have is loan supervision, on the ground this ability is lacking. This implies that loans officers lack the skills and knowledge to make appropriate and periodic reports regarding the way the loans are running, confirming that such employees are deficient of the supervision competence. This study also revealed that the absence of loans officers ability to competently review business environment and its impact on loan performance (Mean=1.69, SD=0.74) (Table 5) is clear manifestation that the loans officer is deficient in exhibiting tendencies of loan portfolio supervision. This is contrary to the fact that a good part of the loans officers’ ability to review business environment and its impact on loan performance is explained by loan portfolio supervision (r2=0.76, CR=8.18, SE=0.13) (Table 5). The discussion above draws policy and managerial implications. This research demonstrates the necessity for management to establish the features that enable loans officers develop the ability or competence to supervise their loan portfolio. Managers can be trained in the aspect of supervision as core key result area. Also, during performance appraisal, employees can be appraised based on their ability to supervise loan portfolios.

Conclusions and recommendations

From the research finds, loan and client projections, client preparation and training, loan portfolio supervision and mobilization and recruitment significantly affect the loans section in the banking sector in Uganda. This paper creates a framework for understanding loans officers’ competences in the banking industry in Uganda. These frames determine


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the operant competences of loans officers in the banking sector. Competence development needs a holistic competency profiling that allows banking organizations to define competence from their own environment. The authors therefore recommend that: the banking sector should provide avenues that enable the employee to develop operant competences based on the prevailing circumstances and environment. There should not be a one answer to all questions given of the dynamism in the environment or the context.

Managers in the banking industry need to explore policies and practices that promote the acquisition of the right competences based on extant environment. Employees need to learn to be flexible and acquire basic skills and knowledge to manage and supervise loans in view of the environment where they do their work. Scholars need to research on the variables that act as precursors to operant competences of loans officers.

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