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Engineered for Tomorrow

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TABLE OF CONTENTS

Sl. No.

Title Author Page

No

1 Performance of bonding layer on the repairing of concrete structure

K.Kumar1 & T Soumya2 01-10

2 Recent developments in mica-epoxy-glass composites and their application in HV rotating machines

A.K.Shukla1 and A.K.Basu2 11-15

3 Room Temperature Preparation of Nanocrystalline Tin Oxide

Sharanya S Nair1 & Ramdas Balan2

16-18

4 A planar UWB antenna with notched bands for WIMAX and WLAN applications

Benjamin I 19-23

5 Smart Wearable Obstetric Assistant and Reminder Manoranjan Kumar1 & Divya.P.K2

24-30

6 Study of Color and Gray Image Denoising using Different Filter Techniques

Aruna Dore 31-36

7 A Survey on Human Sensing Applications using UWB Radar

PrashantSGhulappanavar1 & Kavya B M2

37-42

8 Graphene: A Wonder Material Poornima R 43-50

9 Ethical issues of monitoring alzheimer’s patients Bindiya Patil1, Shruthi B.R2 & Roopashree B.G3

51-54

10 Study of Diode, Bipolar Junction Transistor and Op-amp using MATLAB

Divyashree1 & Shivakanth2

55-59

1 MVJCE-JOURNAL- Vol 4, Issue 2, Dec-2015

K.Kumar, T.Soumya

PERFORMANCE OF BONDING LAYER ON THE

REPAIRING OF CONCRETE STRUCTURE

K.Kumar,

Dept. of Civil engineering, MVJ College of Engineering, Bangalore 560067

T.Soumya,

Dept. of Civil engineering, MVJ College of Engineering, Bangalore 560 067

Corresponding Author: Dr. Krishnan Kumar, Ph.D, Phone :+918971301227,

Email: [email protected]

Abstract: The durability of concrete structure

depends upon the deterioration of concrete,

corrosion of steel and other mechanical

behavior. Cracking and delamination of the

concrete gives alarm to failure of structure.

Deterioration of reinforced concrete

structures is generally manifested in the form

of cracking, spalling, scaling, loss of strength

etc. A proper rehabilitation measure

enhances the trouble free life of the structure.

The selection of material is the most

important step in the repair programme.

Different generic materials were studied for

their performance on the bonding strength

between existing concrete and new overlay is

of major concern to decide the efficiency of

the rehabilitation measures. The bond

performances were evaluated by slant shear,

splitting tensile and flexural tests. Bonding

layer based on epoxy shows efficient

performance.

Keywords: Concrete structures,

deterioration, corrosion, repair, bonding

layer

INTRODUCTION

High quality concrete provides the ideal

environment for reinforcing steel. Steel in

concrete does not corrode due to tightly

adhering protective oxide film formed in the

alkaline environment. This is known as

passive protection. However, iron, the

principal component of steel has a persistent

tendency to return to its natural state, generally

iron oxide or rust, wherever the opportunity

arises. However, if the alkalinity of the

concrete is reduced through carbonation or the

passivity of the steel is destroyed by

aggressive ions like chlorides the structure

starts deterioration. The increase in volume

due to corrosion process causes high radial

bursting stresses around the reinforcing bar

and results in local radial cracks. These

splitting cracks can propagate along the bar,

resulting in the formation of longitudinal

cracks parallel to the bar.

These cracks provide easy access for oxygen,

moisture and chlorides creating a condition in

which corrosion continues and causes further

cracking and spalling. Exposed concrete

surfaces may accelerate corrosion by

providing entry points for moisture and other

corrosive ions. Remedial action must be taken

so that progressive deterioration does not

ultimately threaten the structural adequacy.

While facing the challenge on durable concrete

structures, we are also encountering with the

task of providing durable repairs to the

deteriorating/damaged structures. Many

architects, engineers and contractors in the

country execute concrete repair/rehabilitation

by patch repairs and consider it as an artisan

mailto:[email protected]


K.Kumar, T.Soumya

job. This approach is dangerous and has to be

eschewed. In fact the assessment, design and

implementation of repairs to existing

structures are indeed more complex than those

for new construction

Failure of repair works in most cases will be

due to inadequate bond between parent

concrete and new material. Normally a

bonding layer is applied for better bond

between old and new concrete. There are many

case studies for bond failure due to moisture

entrapment at the bonding layer [G.D.

Shanbag, 2000]. A systematic evaluation of

different bonding layers were carried out based

on the international standard specifications and

other literatures. The cement mortar slurry on

the old concrete substrate and steel surface

offered excellent protection to the bar in the

repair zone [R.W, Lambe, 1990]. However

corrosion of the steel adjacent to the repair in

the surrounding concrete may be accelerated.

This effect is thought to be due to the highly

alkaline mortar making the bar in the repair

zone cathodic to the surrounding concrete

which could become a corroding area by way

of forming macrocell. [Cavalier,P.G, 1982].

The selection of material is the most important

step in the repairs and rehabilitation

programme. The proprietary materials

available in the market has been compared

based on the manufacturer’s literature

normally highlights the composition of the

materials rather than performance

characteristics. In this paper three different

generic material such as cement slurry, acrylic,

epoxy and SBR based bonding layers were

studied for their bond performance as a

bonding layer.

MATERIALS

Sl

No

Description Details

Concrete

1 Cement Ordinary Portland

cement conforming to

IS-456-2000

2 Course

aggregate

Graded coarse

aggregates conforming

to graded aggregates of

normal size greater than

4.75 mm and less than

10 mm of IS-456-20

3 Fine

aggregate

Clean river sand used

as graded fine

aggregates (fineness

modulus of medium

sand equal to 2.6)

conforming to grading

Zone III of IS-383-

1970.

Bonding materials

1 Cement

Slurry

System - Cs

2 Acrylic

resin

System - A

3 Epoxy

resin-two

pack

System - B

4 Acrylic &

Epoxy

System - C

5 Styrene

Butadiene

Rubber

System - E

6 Epoxy &

Hardener

one coat

with sand

sprinkling

System - Ey

The bonding materials were applied on the

prepared surfaces of the old concrete. The


K.Kumar, T.Soumya

surface preparation was carried out in

accordance with ASTM D 4259 – 88

(Reapproved 1992).

METHODS

Slant Shear test [ASTM c882-91]

The bond strength of old to new concrete is

determined by using two equal sections of

76.2*152.4mm Portland mortar cylinder, each

section of which has a diagonally cast bonding

area at a 30 angle from vertical axis. The

specimens were subjected to cure for 28 days.

After 28 days of curing the slanting phase of

the specimens were taken out and air dried for

24 hrs. The dry surface was sand blasted in

order to get perfect adhesion between the

concrete and the bonding layer. Bonding

layers as in material selection were applied on

the slanting (elliptical) portion of sand blasted

surface. The new concrete was poured over

the elliptical surface immediately after

application of bonding layer. The new

concrete was subjected to curing for a fixed

time depending upon the type of system. After

curing, the specimens were subjected to

compression test. The tested specimen for

slant shear is as shown in Fig 1. The bond

strength was calculated by dividing the load

carried by the specimen at failure by the area

of the bonded surface.

Tensile Strength Test

The tensile strength of concrete is measured

indirectly by finding the tensile strength of

cement, sand and mortar to which standard

briquettes are prepared using 1:1.14 cement

mortar with W/C ratio of 0.45 and the having

standard dimensions and allowed for curing.

For each experiment six specimens were used.

The pure mortar specimens were subjected to

tensile test, and the breaking load was noted.

After the specimens were split into two pieces

the split specimens were joined with each

other using different bonding layers and the

test results were compared with the original

mortar specimen without any bonding layer.

The tensile strength of the specimen was

calculated using the formula

Tensile strength Tensile Load (N)

(N/mm2) = Area of the specimen (mm

2)

Flexure Test [BIS 516-1959, ASTM C78-94]

Flexural strength of the concrete beam of size

500*100*100 mm was cast and tested by third

point loading at a rate of 1.2 KN/min.

Flexural strength is expressed in terms of the

modulus of rupture at the beams were cast

using (1:1.18:2.77) M30 concrete with the W/C

ratio of 0.45 and subjected to curing for 28

days. Cured specimens were subjected to third

point loading, and the load at failure was noted

(before repair). After the specimens were

broken into two, the two pieces were joined

with different systems of bonding layers then

tested for flexural strength.

RESULTS AND DISCUSSIONS

Slant Shear test

One of the critical factors governing the

achievement of an effective repair is good

adhesion at the interface of the repair material

and the concrete substrate. Good adhesion is

imperative for structural repairs where

monolithic character is required for the

transfer of load. Bonding agents play a

significant role where it is critical to ensure

bond at the interface [Noel P. Mailvaganam,

1997]. The performance of different bonding


K.Kumar, T.Soumya

layers in slant shear test is given in Table. 1 in

which the nature of failure represented by

bond failure is the failure occurred at the shear

plane. The monolithic failure is represented by

cracking other than shear plan.

The result shows that epoxy-bonding layer

exhibited better performance with average

slant shear strength of 5.5 N/mm2. Bonding

layer with cement slurry has shown slant shear

strength of 3.00 0.2 N/mm2.

System A and C

have performed in the same manner. Other

systems have shown inferior performance.

While comparing the nature of failure, epoxy

based system has a monolithic failure, which

indicates the system has superior performance

compared to all other systems. It is observed

that in the bond failure the new concrete mass

separated from the old concrete. The bonding

layer thickness shall be optimum. When the

thickness of binder is thinner it will perform

better. The stiffness of the aggregate-binder-

aggregate system increases as the bonding

layer gets thinner [Dong wang, 2013]. System

E performed almost like cement-based system.

Monolithic failure observed in epoxy System

and bond failure observed in system – Cs & C

which is the typical bonding layer failure.

However the system – Cs & C performed for

higher shear strength. System A shown

bonding failure elucidate acrylic resin is not

suitable for bonding old and new overlay.

System – B performed as like system Ey but

failed lesser in shear strength.

Direct Tension

Triplicate standard briquettes were made and

cured for 28 days. The cured specimens were

tested for direct tensile strength. The split

portions of the tested briquettes were coated

with system B and epoxy and bonded together.

After the curing of the bond coat again these

specimens were tested for direct tension.

Results of the bonded briquettes with different

bonding materials were shown in Table 2.

This results shows better performance for

epoxy based system. None of the specimen

bonded with epoxy system failed at the bonded

plane. In the case of System B bonding layer

specimen, out of three failed very near to the

bonded plane. The system – B has an

advantage of epoxy.

Flexure

Flexural specimens of standard size (100

mm*100 mm*500 mm) were cast and cured.

These specimens initially tested for the

flexural strength by applying point loads at

middle third position. Tested specimens were

joined with System-B and System-Ey and

allowed for 24 hours of curing period.

After the curing is over these specimens were

tested again for flexural strength. Test results

were shown in Table 3 which shows both the

systems performed as original beams. System-

Ey slightly reduced the flexural value than the

System-B. This may be due to improper

wetting of the bonding portions or improper

sealing of the bonding material.

Repaired Beam

To prove the efficacy of the bonded materials,

these systems were imparted actually in the

affected beams for rehabilitation work. Two

affected beams reinforced with nominal design

were selected is shown in Fig. 2. Middle

portion of the tensile zone has been provided

with untied lapping arrangement. These

beams were initially loaded at the middle third

points and tested for its bonding behavior at

the lapped portion.

The beams under test have been coated with

both epoxy bonding and cement slurry

bonding layer and the results of which are


K.Kumar, T.Soumya

shown in Table 4. These beams were

subjected for the flexural behavior, where the

cement slurry system failed at the lapped

portion indicating a bond failure. The load

taken was less than the original. In the case of

epoxy based bonding system the failure

occurred at the adjacent place of the bonding

area. The visual observation has shown that

the new material is intact with the bonding

layer along with old concrete, which is shown

in the Fig. 3. The load taken has exceeded the

original.

Liquid epoxy in tacky conditions has been

found to be an excellent bonding coat. When

large area is to be concreted the time lag

between application of the epoxy bond coat

and subsequent placement of new concrete

may increase. This results in the epoxy being

partially or fully set and consequently it acts as

a de-bonding agent rather than a bonding

agent. This is not because of the failure of the

material but due to the two-pack epoxy not

being utilized properly. Hence, precautionary

measures must be considered while selecting a

bonding material and method of application.

Conclusion

Thus the comparative performance study

determined the use of several bonding

materials for repair / rehabilitation work has

derived the following conclusions.

Bond between old and new concrete is an

essential factor to be considered for the better

repair methods.

A bonding agent with better bond strength will

show the monolithic failure in slant shear

strength test.

Proper surface preparation is necessary before

application of any bonding layer.

Before casting new concrete an additional wet

of bonding layer shall be provided for better

adhesion.

Epoxy based systems are proved better in bond

strength under slant shear, splitting tensile and

flexural beams evaluations.

REFERENCES

1. Dong wang et al, “Experimental Evaluation of a

Simple Contact Model Containing Two Elastic

Particles Bonded by a Thin Layer of Viscoelastic

Binder”, Journal of Nanomechanics and

Micromechanics, Volume 3, Issue 4 (December

2013).

2. G.D. Shanbag, P.G. Gokhale and B.V.

Bhedasgaonkar, “Restoration of hammer

foundations in forging industry – a case study” The

Indian Concrete Journal, January(2000), pp 46-48

3. Noel P. Mailvaganam, “Effective Use of Bonding

Agents”, Construction Technology Updates,

National Research Council of Canada, December

1997

4. R.W,Lambe, M.J.Aumphrey, T.F.Watkins,

“Development of materials for repair and protection

of reinforced concrete”, “corrosion of

reinforcement in concrete”, edited by C.L.Page

(1990), pp 471 – 485.

5. Cavalier,P.G, and Vassie.P.R, “Investigation and

repair of reinforcement corrosion in a bridge deck”,

proc., Instn., of civil engg., part I, (1982), 72, 401 –

419.

6. ASTM D4259-88 (Reapproved 1992) - “Standard

Practice for Abrading Concrete”.

7. ASTM c882-91, “Standard Test Method for Bond

Strength of Epoxy Resin systems used with

concrete by slant shear.

BIS 516-1959, Indian Standard Methods of

tests for strength of concrete.

ASTM C78-94, Standard Test Method for

Flexural strength of concrete (using single

beams with third point loading)

http://ascelibrary.org/journal/jnmoco

http://ascelibrary.org/journal/jnmoco


K.Kumar, T.Soumya

Figure 1: Slant shear tested specimen

Figure 2: Beam before repair

Figure 3: Beam repaired with bonding layer


K.Kumar, T.Soumya

Figure 4: Performance of bonding layer in repaired beam

Table: 1 Slant shear behavior comparison of bonding layer

Batch No.

Type of

Bonding

Layer

Load at

failure KN

Bond

stress MPa

Nature of failure

I System-Cs 25.22

29.13

28.54

2.77

3.19

3.13

Bond failure

Bond failure

Bond failure

II System-A

24.69

25.07

14.34

2.71

2.75

1.57

Bond failure & cracking at new

concrete.

Bond failure & cracking of upper

layer.

Bond failure

III System-B

26.36

15.66

2.89

1.72

Cracking failure, No bond failure

Shear failure

IV System-C

29.13

24.32

22.00

3.19

2.67

2.41

Bond failure

Bond failure

Combined failure

VI System-E

09.53

10.28

07.23

1.04

1.13

0.79

Bond failure

Bond failure

Bond failure


K.Kumar, T.Soumya

VII System-Ey 27.57

51.62

54.84

3.02

5.66

6.01

Monolithic failure

Monolithic failure

Monolithic failure

Table 2: Performance of bonding layer in direct tension

Before Repair

After Repair

Batch No.

Load at failure

in KN

Direct

tension

N/mm2

Type of

Bonding

Layer

Load at

failure in

KN

Direct

tension

N/mm2

I

2.240

1.930

1.689

3.58

3.09

2.50

System Ey

1.612

2.387

1.086

2.48

3.27

1.67

II

1.889

1.973

1.488

3.02

3.16

2.38

System B

1.965

1.391

1.735

2.91

3.02

2.31

Table 3: Performance of bonding layer in flexure

BEFORE REPAIR

AFTER REPAIR

Specimen

No.

Load at

failure in

KN

“a” in

Cm

Fb

N/mm2

Bonding

Layer

Load at

failure in

KN

“a” in

Cm

Fb

N/mm2

1

13.5

16.10

6.52

System Ey

9.5

17.00

4.84

2

11.0

17.85

5.89

System B

12.0

17.00

6.12


K.Kumar, T.Soumya

Table 4: Bonding layer performance on the repaired RCC beam

BEFORE REPAIR

AFTER REPAIR

Beam No.

Load at failure in

KN

Bonding Layer

Load at First

Crack in KN

1.

25.50

Cement Slurry

22.50

2.

32.50

Epoxy

61.00


A.K.Shukla and A.K. Basu

RECENT DEVELOPMENTS IN MICA-EPOXY-

GLASS COMPOSITES AND THEIR APPLICATION

IN HV ROTATING MACHINES


Dept. of Chemistry, MVJ College of Engineering, Bengaluru-560 067.

Lakshmanan Isola Pvt. Ltd., Quality and R&D, Bengaluru-560 025

Corresponding author: e-mail : [email protected]

Abstract:By virtue of high corona resistance

Reconstituted mica constitutes the most

important component of insulation in high

voltage motors and generators. The paper

describes the recent developments in

processing, characterization, and application

of the state-of-art dielectric composite

insulating materials based on reconstituted

mica and epoxy resin reinforced with glass

fabric (MEG). MEG composites in the form

of folium/tapes after curing show high

dielectric strength >35 kV/mm, very low

dissipation factor (Tan δ) value 0.075 at 1 kV

at 25°C and very little increase in Tan δ with

rise in temperature upto 155°C and voltage

upto 12kV. Thermal aging studies conducted

at 180, 200 and 220°C for 28 days on mica-

epoxy-glass laminate after curing show fairly

good retention of dielectric strength,

indicating their suitability for application in

thermal class 155 motors and generators.

Keywords: Mica paper, epoxy resin,

reconstituted mica, electrical insulation,

dielectric composites

1.0 INTRODUCTION

Use of mica is essential in the main insulation

of electrical rotating machines operating at 2.5

kV or above owing to its unique resistance to

corona discharges[1-5]

. Being a brittle and sheet

like mineral, mica has limited scope for

application. However by virtue of its unique

property of splitting into thinest flakes, it is

converted into a thin paper-like material called

reconstituted mica using thermal, chemical

and mechanical processes. To enhance the

inherently low mechanical strength (6-12

N/cm) of such a paper it is reinforced with a

layer of glass fabric or a polymer film and

bonded with a synthetic thermosetting resin[6-8]

.

Application of resin-rich mica paper-epoxy

based composites involves thermo

compression of insulated copper bars till

consolidation in the hydraulic press followed

by post curing in the oven[9]

. During the

process the bonding epoxy resin initially

softens on heating in the press and under high

pressure the fluid resin fills all the voids and

the excess resin oozes out from the sides, thus

producing a void-free insulation. The ultimate

objective of this insulation technology is to

incorporate maximum quantity of mica in the

void-free insulation[3-5]

.

In this paper the authors have presented the

development, processing and characterization

of state of the art reconstituted mica – epoxy-

glass reinforced composites suitable for resin-

rich technology. Results of cured composites

after their respective processing and after heat

ageing are also discussed. Recommendations

for their application in high voltage rotating

machines have also been given.

2.0 EXPERIMENTAL

2.1 MATERIALS USED:

2.1.1 Reconstituted Mica: Muscovite mica,

general formula, KH2Al3(SiO4). 2H2O,

available from Jharkhand, India is processed

into reconstituted mica papers of different

grades depending upon thickness, unit weight,

porosity and impregnation time. Following




two grades of mica paper complying with the

requirements of IEC 60371-3-2 and

manufactured by m/s Lakshmanan Isola,

Bangalore were used in preparation of

composites.

TABLE 1: Characteristics of reconstituted mica

Mica paper

grades→

Characteristics↓

11/21-75

(MMc)

11/21-

150

(MMc)

Mica grade Muscovi

te

calcined

Muscovi

te

calcined

Thickness, mm 0.060 0.115

Unit weight, g/m2

75 150

Tensile strength,

N/cm

5 - 10 6 - 12

Porosity

(Gurleyhill),

s/100ml

3000-

6000

5000-

10000

Impregnating time,

s

20 - 60 150 -

300

2.1.2 Calcined mica paper: Mica is calcined

in rotary kiln at 770-830°C and after chemical

and mechanical treatments converted into pulp.

Specific particle size fractions separated by

vibro-screening are mixed and processed into

a paper like material. Calcined grades 11/21-

75 and 11/21-150 (MMc) with characteristics

as given in Table-1, has been used in MEG

composites.

2.2 Resin binder: Unmodified Epoxy

Novolac Resin EPN 1138 having epoxy

equivalent 176-181 g/equiv and viscosity

35000-70000 cP from Huntsman High

Performance Polymers was used for

preparation of composite folium.

2.3 Accelerator: Lekutherm- Accelerator

KU-6519 based on Boron trifluoride-amino

complex from Rhein Chemie, Germany was

used for catalytic curing of epoxy resin.

2.4 Reinforcement: Electrical grade glass

cloth having low alkali content (Na2O

<0.05%), low sizing content (<2%) and unit

weight 25 and 35 g/m² manufactured by

K.E.Technical Textiles, Kharagpur, have been

used as reinforcement in the composites.

3.0 DEVELOPMENT OF MEG

COMPOSITES

3.1 Processing of Mica-Epoxy-Glass

Composites:

Process involves application of pre-accelerated

epoxy-novolac varnish on to the glass cloth

and the calcined mica paper, lamination of the

two layers followed by drying & partial

polymerization in a horizontal drying

machines having four temperature zones

ranging from 70-150°C. Important process

parameters to be controlled are varnish

composition, viscosity, temperature and

machine speed in order to achieve the

specified characteristics in the product.

3.2 Control of Process parameters:

(a) Resin content and composition: Epoxy-novolac resin is dissolved in a suitable

proprietary solvent keeping the resin content

in the range 15-30% by weight. Recommended

quantity of the accelerator is dissolved in the

varnish and the solid content are verified by

drying a portion of the varnish in the oven and

measuring the weight after cooling.

(b) Viscosity of the composition: Viscosity of the above varnish is measured

using LG (DIN) cup and is maintained in the

range 8-18 sec.

(c) Machine speed: Speed of movement of

glass fabric and the mica paper is maintained

in the range 1-6 M/min as required according

to the temperature in drying chamber zones.

(d) Temperature : Temperatures in the 4

zones of the horizontal drying chamber are

maintained in the range 60-160°C according to

the resin flow required in the B-stage product.

3.3 Characterisation of the B-stage folium :

The product obtained in B-stage in the form of

folium is characterized for thickness, unit

weight, mica and resin content, resin flow and

stiffness. Resin Flow is an important

characteristic and is measured by placing 4

layers of 4” x 4” size after weighing, between



the hot platens of the hydraulic press at a

temperature of 130-150°C and pressure of 5-

10Kg/cm2. Stiffness of the folium specimen is

measured by using Stiffness Tester according

to the standard IEC method.

3.4 Curing of the composite folium: Curing

conditions have been optimized and

recommended as 4-6 hrs at 150-180°C.

4.0 CHARACTERISATION

4.1 MEG Composites in B-stage : They are

characterised for thickness, total substance,

mica, glass and resin content, tensile and

electrical strength (BDV). Typical

characteristics of MEG composite tapes of the

grades 180:75 and 305:150 are presented in

Table-2.

TABLE-2: Characteristics of MEG composites in

B-stage

Characteristics MEG

(180:75)

MEG

(305:150)

Thickness, mm 0.13 0.22

Total substance,

g/m2

181 306

Mica content, % 41.5 49.5

Resin content, % 38.8 38.5

Glass content, % 19.3 11.5

Resin flow,% 19.5 20.2

Tensile strength,

N/cm width

221 235

Breakdown

voltage, KV

> 5.0 > 6.0

4.2 MEG Composites after cure :

a) Dielectric Strength : Laminate specimens

were prepared from the B-stage MEG

composite folium, cured and subjected to

dielectric strength measurements using

„Temaco‟ make BDV Tester. The values are

plotted against the temperature at which the

test was conducted, and shown in fig. 1

b) Dissipation Factor (Tan δ) : „Tettex‟

Schering Bridge model 2801 was used to

measure Tan δ at normal as well as at elevated

temperatures i.e. 25 and 155°C. Effect of rise

in voltage at 50Hz on Tan δ was studied and

the comparative results are plotted in Fig.3.

c) Stiffness/Flexibility Study : This

characteristic was studied on both the grades

of MEG composites using Stiffness Tester

conforming to JIS C2116-1992 supplied by

VonRoll Isola. To check the storage life of the

MEG composite tapes, the bending stiffness

values are plotted against storage period at

room temperature in fig.5.

d) Thermal Aging Study: Thermal aging

was conducted at 180, 200 and 220°C for 28

days on insulated copper bars with both grades

of the MEG composite tapes and BDV was

measured at different intervals. Results are

plotted in Fig.6.

Fig.2 : Dielectric strength vs. Testing temp.

5.0 RESULTS AND DISCUSSION

5.1 Dielectric strength : The plot of

dielectric strength values of the cured MEG

laminate specimens measured at different

temperatures, as shown in fig.1, indicates a

reduction in the dielectric strength with

increase in the testing temperature. However,

the actual value at 155°C still remains quite

high at 38kV/mm indicating its suitability as

insulation at the machine operating

temperature of 155°C.

5.2 Dissipation Factor vs. Voltage: Plots of

Tan δ against voltage (Fig.3) show little

increase with voltage upto 12 kV at 25°C

temperature and also at 155°C indicating good



resistance to corona in the insulation under

these conditions.

Fig.3: Plot of Tan δ vs. Voltage

5.3 Dissipation Factor vs. Temperature:

Plots of Tan δ at 1 kV, 50Hz frequency against

temperature up to 180°C shown in Fig.4 show

very low values which do not increase

appreciably with the rise in temperature. It is

to be noted that Tan δ values for the cured

MEG tape having higher mica content are

lower as compared to MEG with less mica.

Fig.4: Plot of Tan δ vs. Temperature

5.4 Stiffness of MEG composite tapes: The plot of Bending stiffness values (Fig.5) of

MEG tapes show significant increase in

stiffness starting from 20 N/m before curing

and rising to above 100 N/m, after 60 minutes

of curing at 160°C. This is due to

consolidation of the epoxy resin.

Fig.5: Plot of Stiffness vs. Curing time

5.5 Thermal aging study: Plots of dielectric

strength of MEG laminate versus Aging period

in days, (Fig.6) show the deterioration in

dielectric strength during aging at 180, 200

and 220°C. After 28 days of thermal aging the

dielectric strength has fallen to 39, 26 and

20kV/mm respectively.

Fig.6: Plot of Dielectric strength vs. Aging time

6.0 RECOMMENDATIONS FOR

APPLICATION IN ROTATING

MACHINES

6.1 As Conductor Insulation: Lower

thickness (0.13 mm) tapes of MEG composite

(grade 180:75) in B-stage are suitable for

application as half lap, conforming to the

copper bars to act as conductor insulation.

They have shown very high dielectric strength

and very low dissipation factor after curing.

6.2 As Main Insulation : MEG tapes of

higher thicknesses (0.18 or 0.22 mm) are

suitable for application as one and half lap on

the straight portion of the coils and should be

hot-compressed (2.0-3.0 MPa) in the



hydraulic press for consolidation. After

cooling while in the press, they are removed

and subjected to curing & post curing in the

oven at 160°C.

6.3 Curing Conditions : Curing : 4-6 hrs at

150-180°C ; Post curing : 8-12 hrs at 140-

160°C

7.0 CONCLUSION

Following conclusions can be drawn from the

above studies. Cured MEG composites, show

a very little increase in Tan δ with rise in

temperature and voltage. At 25°C it rises from

0.008 to 0.032, while at 155°C Tan δ rises

from 0.042 to 0.110, as the voltage increases

from 1 kV to 12 kV in both the cases,

indicating their suitability as conductor and

main insulation. MEG composite having

higher mica content, after cure has lower

values of Tan δ at elevated temperatures than

those for the MEG laminate containing lower

mica content.

Good retention of dielectric strength of MEG

composites (originally 45 kV/mm) after

thermal aging for 28 days at 180, 200 and

220°C showing the

residual dielectric strength values at 39, 26 and

20 kV/mm respectively has been observed.

Mica-Epoxy-

Glass composites have shown the suitability

for application as conductor insulation and

also main insulation for thermal class 155

rotating machines.

ACKNOWLEDGEMENT

The authors are grateful to the Managements

of The MVJ College of Engineering and m/s

Lakshmanan Isola Pvt. Ltd., Bangalore for

constant support in the research work and

permission for presentation of this

developmental work.

REFERENCES: [1] A.K. Shukla & A.K. Basu, “Advanced micaceous

composite materials and their application in high

voltage rotating machines and fire resistant cable

insulation”, Proceedings of International Conference on

Polymeric Materials for Power Engineering, CPRI,

Bangalore, October 6-8, (2007).

[2] A.K.Shukla & M. Surekha, “Advanced silicone

bonded micaceous composites and their application in

traction motors”, National Conf. on Futuristic Polymer

Materials (FPM-2008), R.V.College of Engineering,

Bangalore, 26th

& 27th

Sept‟(2008).

[3] A.K.Shukla , “Processing, Characteristics and

Applications of Dielectric Composites based on

Reconstituted Mica for High Voltage Rotating

Machines”, ISAMPE National Conference on

Composites ( INCCOM-7), National Aerospace

Laboratories, Bangalore-17, Dec. 4-5, 2008.

[4] A.K.Shukla & A.K.Basu, “ Advanced Dielectric

Materials based on Mica for High Voltage generators,

Motors and Cable Insulation”, National Seminar on

maintenance of Generators and Motors, Indian Institute

of Plant Engineers, Karnataka Chapter, Bangalore,

July‟2007.

[5] H. Yoshida and H. Mitsui ,”Rotating machine

Insulation”, IEEE Trans. on Electrical Insulation Vol.

EI- 21, No.6, December 1986.

[6] Aleksandrov N.N., et.al., “Electrophysical

properties of mica papers differing in fractional

composition.”, Elektrotekhnika, vol.53, No.10, pp.31-

33, 1982.

[7] Mitsui H., et.al., “Improvement of Rotating

Machinary Insulation characteristics by using Mica

Paper containing Aramid Fibrid.” , IEEE Trans. on

Electrical Insulation Vol. EI-18, No.6, December 1983.

[8] Kenzo Kadotani, “Effect of Mica Paper on

Properties of Coil Insulation”, Electrical Engineering in

Japan, Vol.102, No.6, pp.1-8, 1982.

[9] Nurse J.A., “Development of modern high-voltage

insulation systems for large motors and generators”,

Power Engineering Journal, pp.125-130, June‟ 1998.


Sharanya S Nair, Ramdas Balan

ROOM TEMPERATURE PREPARATION OF

NANOCRYSTALLINE TIN OXIDE

Sharanya S Nair

Department of Chemical Engineering

MVJ College of Engineering

Bangalore, India

[email protected]

Ramdas Balan

Nano Research Lab, Department of Physics

MVJ College of Engineering

Bangalore, India

[email protected]

Abstract— Nanocrystalline SnO2 was

prepared at room temperature by acid

treatment of precipitation method prepared

precursor, CaSn(OH)6 using NaOH as

precipitant. The precursor and acid washed

compounds were characterized by X-Ray

Diffraction (XRD), Brunauer – Emmett –

Teller (BET) and Scanning Electron

Microscope (SEM) analysis. X-ray

diffraction confirms single phase SnO2

dissolute from Brutite structured

CaSn(OH)6 by acid treatment. The

crystallite size was calculated using

Scherrer equation found to be in the range

of 10 - 20 nm. SEM micrograph and BET

confirms the porous nature of the prepared

SnO2.

Keywords— Tin oxide ; Nanocrystalline;

Scanning electron microscope; BET

I. Introduction

Tin Oxide (SnO2) is an important n type

wide band gap (Eg=3.6eV at 300K)

semiconducting oxide, studied as a potential

candidate for transparent conducting oxide

(TCO) [1], dye sensitizer solar cells (DSSC)

[2], lithium rechargeable batteries [3], gas

sensor [4, 5], catalysis [6 ,7] and antistatic

coatings [8] due to its physiochemical

properties. Many of its applications are

surface dependent which required large

surface area and porous nature. In this

regard, there are many reports on

conventional techniques to prepare porous

SnO2 with high surface area [9, 10]. Also,

there are few reports on preparation of

porous SnO2 by non conventional technique

by dissolution of complex oxide obtained by

heat treatment of the hydroxides such as

CoSn(OH)6 [11], CuSn(OH)6 [12] and

CaSn(OH)6 [13].In this paper, we report

the preparation of porous nanocrystalline

SnO2 by direct dissolution from the

prepared hydroxide i,e CaSn(OH)6 in

single step.

II. Experiment

A. Preparation of CaSn(OH)6

All chemical reagents used in this

experiment were analytical grade. 1M of

aqueous solutions of each CaCl2.5H2O and

SnCl4.2H2O were added to 500 ml of 2M

NaOH solution with constant stirring. A

white precipitate was formed. The precipitate

was then washed using distilled water to

remove all chloride ions and filtered. Then

the precipitate was dried in hot air oven at 80

oC for 12 h. The resultant white powder is

called as precursor.

B. Preparation of SnO2

The precursor was mixed with addition of 50

mL of 1.0 M HCl with constant stirring for

1h. Then, the product was rinsed with

distilled water until the pH of the solution

was neutral. And finally, centrifuged and

dried in hot air oven for overnight.

The precursor and acid treated products were

characterized by Powder X-ray diffraction

(PAN analytical X’Pert Pro) with CuK

radiation, Brunauer – Emmett – Teller (BET)

nitrogen adsorption–desorption (Nova

2000E) and Scanning electron microscopy

(HITACHI Model S-3000H) for phase

identification, purity and morphological

studies.



III. Results and Discussion

A. X-ray Diffraction studies

Fig. 1 shows the XRD pattern of the precursor prepared by precipitation method. The pattern matches well with the standard data (JCPDS card No. 09-0030) of CaSn(OH)6 with no additional peak confirms single phase formation, crystallizing in cubic structure with lattice parameter a = 0.814(0) nm calculated using least square method.

Fig. 2 shows the XRD pattern of acid treated product, confirms single phase SnO2 matching with the standard data (JCPDS card No. 041-1445). Broadened XRD peaks concludes the nanocrystalline nature of the prepared SnO2 compounds, crystallite size was calculated to be 10 - 20 nm using

Scherrer equation, d = (0.9 )/ BCos .

B. Surface Area Analysis

Fig. 3 adsorption and desorption isotherm of

prepared SnO2 clearly shows type IV kind,

revealing the presence of mesoporous. BET

surface area of the prepared SnO2 was

measured to be 160.55 m2/g.

C. Morphological studies

Fig. 4 shows the SEM micrograph of SnO2.

The particles were in the size range of 100

nm – 500 nm with porous nature.

IV. Conclusion

SnO2 was prepared at room temperature by

dissolution of CaSn(OH)6. Powder - XRD

and BET characterization confirms single

phase, porous, nanocrystalline nature of the

prepared SnO2.

References [1] M.J. Van Bommmel, W.A. Groen, H.A.M.

Vanhal, W.C. Keur, T.N.M. Bernards, J. Mater. Sci.

34 (1999) 4803.

[2] Ferrere S, Zaban A, Gregg B A. Dye sensitization

of nanocrystalline tin oxide by perylene derivatives. J

Phys Chem B 101(1997) 4490.

[3] Lou X W, Wang Y, Yuan CL, Lee J Y, Archer L

A . Template-free synthesis of SnO2 hollow

Figure 1: Powder XRD pattern of the precursor

Figure 2: Powder X -Ray Diffraction

pattern of acid washed precursor

Figure 3: Nitrogen adsorption and desorption plot of

prepared SnO2

300 nm 500 nm



nanostructures with high lithium storage capacity.

Adv. Mater 18 ( 2006) 2325.

[4] Yin X M ,LiC C, Zhang M, Hao Q Y, Liu S, LiQ .

SnO2 monolayer porous hollow spheres as a gas

sensor. Nanotechnology 20 (2009) 455503

[5] Wang Y L, Jiang X C, Xia Y N. A solution-phase,

precursor route to poly-crystalline SnO2 nanowires

that can be used for gas sensing under ambient

conditions. J. Am. Chem Soc. 125 (2003) 16176.

[6] Zhang Y, Kolmakov A, Lilach Y and Moskovits

M, J. Phys. Chem. B,109 ( 2005)1923.

[7] C. P. Nicholas and T. J. Marks, Nano Lett., 2004,

4, 1557.

[8] A. Tischner, T. Maier, C. Stepper and A. Kock,

Sens. Actuators, B, 134 (2008) 796.

[9] W. Wei, et al., SnO2 hollow nanospheres

assembled by single layer nanocrystals as anode

material for high performance Li ion batteries, Chin.

Chem. Lett. 26 (2015) 124.

[10] Jian-Ping Ge, Jin Wang, Hao-Xu Zhang, Xun

Wang, Qing Peng, Ya-Dong Li, High ethanol

sensitive SnO2 microspheres, Sensors and Actuators

B 113 (2006) 937.

[11] Jiarui H, Liyou W, Gu C, Zhai M and Liu J,

Preparation of hollow porous Co-doped SnO2

microcubes and their enhanced gas sensing property,

Cryst Eng Comm, 15 ( 2013) 7515.

[12] Huang J, Xu X, Gu C, Yao S, Sun Y and Liu J,

Large-scale selective preparation of porous SnO2 3D

architectures and their gas-sensing property, Cryst

Eng Comm, 14 ( 2012), 3283.

[13] Wei W, Gao S , Yang Z , Wu Y, Chen C, Guo L

and Li J, Porous SnO2 nanocubes with controllable

pore volume and their Li storage performance, RSC

Adv., 4 (2014) 13250

Acknowledgement

The authors thank MVJCE, management and

VGST, Grant in aid scheme, Government of

Karnataka, for financial support.


I. Benjamin

A PLANAR UWB ANTENNA WITH NOTCHED

BANDS FOR WiMAX AND WLAN APPLICATIONS

I. Benjamin

Dept. of ECE MVJCE, Bangalore

[email protected]

Abstract— A planar UWB antenna with

notching at two various frequency ranges is

designed and analyzed. This antenna consists

of a radiating patch and a partial ground

plane. The dual notching characteristics in

the antenna are brought about by the

inclusion of a T-shaped stub in the square

patch and a couple of U-shaped parasitic

strips along the feedline. This design works in

the well in the 3.1-10.6 GHz with the VSWR

< 2 and band notching at 3.26-3.9 GHz

(WiMAX) and 5.16-5.4 GHz (LOWER

WLAN). Hence this antenna will serve a good

candidate for various UWB applications.

Index Terms—Planar antenna, ultrawide-

band (UWB) antenna, dual notching.

I. INTRODUCTION

IN RECENT p a s t , the need for

antennas that work in various multiband

applications in the latest wireless

communication systems have interested

many researches in the ultrawideband (UWB)

systems. The range of operation of UWB

antenna is 3.1-10.6 GHz and it has significant

advantages such as low cost, low spectral

power density, high precision ranging, low

complexity, resistant to jamming and

multipath, works well for short range high

speed wireless communication purposes etc.

[1].

There are many number of antennas

with notched band property have been

introduced, and various methods have

been proposed to obtain the desired

characteristics. The widely used techniques

are bring about slots on the patch or on the

ground plane in shapes such as H-shaped

slot [2], U-shaped slot [3], C-shaped slot

[4], etc. Making use of parasitic strips [5]

near the radiation elements or the ground

plane is another method to form notched

bands. So far, most of the before models were

intended to bring about single-notched-band

design and there have been few works on the

dual notched band designs. Dual-notched-

bands antennas have been recently reported

[6]–[8]. In these models, by inserting the

proper slits in the interior of the radiation

element and the ground plane, two rejected

bands have been obtained.

Most of these before mentioned models

have the same dis-advantage of poor voltage

standing wave ratio (VSWR) of the dual

notched bands. In this letter, a novel UWB

planar antenna with dual notched bands a t

t h e W i M A X an d l o w er W LA N

b an d s is proposed. A T-shaped stub in the

radiation patch and two U-shaped stubs

beside the feeding line are used to realize

dual-band-notch characteristic.


I. Benjamin

Fig. 1. Configuration and parameters of the UWB

antenna (unit: millimeters).

There are designs which use two T-shaped

stubs to achieve a notched band [9], and in

this design two U-shaped stubs along sides

of the feeding line are first used in the

UWB antenna to achieve a notched band.

The parametrical analyses of these filtering

structures are carried out. An antenna

prototype is designed and fabricated to

demonstrate the proposed strategy. The

proposed antenna structure is designed

using the CST Microwave Studio and

simulation results are obtained. The

simulation indicates dual bands rejection

with central frequencies of 3.6 and 5.3

GHz respectively, and significant notched

band characteristics.

II. ANTENNA DESIGN AND

RESULTS A.UWB Monopole Antenna

Fig. 1 shows the design specifications of a

UWB monopole antenna. The antenna is

fabricated on FR-4 substrate with dielectric

constant of 4.3 and i ts thickness is taken as

0.8 mm. The radiating square patch and

feeding line are printed on the top side of

the substrate and the partial ground plane on

the bottom side. The width of the microstrip

feedline is taken to be 1.6 mm to obtain a

characteristic impedance of 50. The thickness

of the annealed copper material for the

conducting part is 0.018mm. The optimization

is carried out and the final design

specifications of the various parameters are

listed out as follows: a = 2mm, b = 2mm, f =

13.5mm, s = 14.5mm, l = 32mm, w = 26mm,

m = 14mm, n =13mm.

In the presented design, an equivalent

dipole antenna is obtained between the top

monopole antenna and the bottom partial

ground plane [9]. Thus the characteristic

impedance of the antenna is affected by the

current distribution on the design. By cutting

the two notches of suitable dimensions at the

two lower corners of the patch, it is the

same with [10]

Fig. 2. VSWR plot of the proposed antenna without notched bands.

that the impedance bandwidth can be

improved to a considerable extent. This

phenomenon occurs because the two notches

affect the electromagnetic coupling between

the rectangular r a d i a t i n g patch and the

ground plane is affected by the two notches

which cause the improvement in the

impedance bandwidth.

The distance between the rectangular


I. Benjamin

radiation patch and ground plane is taken to

be 1mm, which is also a significant

parameter to control the impedance

bandwidth. The patch and the ground plane

form an equivalent dipole antenna. The

ground plane is a partial plane. The proposed

antenna can obtain high gain at low and high

frequency with partial ground plane.

B. UWB Monopole Antenna with Two

Notched Bands

To obtain dual notched bands, a T-shaped

stub on the rectangular radiating patch and a

pair of U-shaped stubs along sides the

feeding line are implemented to generate

notched bands at the desired central

frequencies of 3.6 and 5.3 GHz, respectively.

The configuration is shown in Fig. 2.

Fig. 3. Configuration and parameters of the UWB antenna with dual notched bands.

We may note that the currents will be

mainly distributed around the filter

structures and will be guided in opposite

directions between the interior and exterior

edge. Thus increased attenuation occurs

near the resonant frequency because of the

resultant radiation fields which cancels

each other and this phenomenon results in

the notched bands.

In order to do a detailed study on the

design of this antenna, some parametric

investigation and analysis is done to

optimize and get the inference of the

variations in the results. The T1, T2, U1

and U2 are the vital parameters which

determine the characteristics and operations

of the notched bands. Changing these

parametric values changes the position or

shifts the central frequency of the notch

bands to either higher or lower values.

Fig. 4. VSWR plot of the proposed antenna with T-shaped stub

Fig. 5. VSWR plot of the proposed antenna

with U-shaped parasitic strips.


I. Benjamin

The notch for the first coming WiMAX

band is significantly controlled by the T-

shaped stubs in the rectangular radiating

patch. The optimized values for the T1 and T2

are obtained as 6mm and 7.5mm respectively.

It was found that increasing T1 value shifted

the central notch frequency towards lower

values and decreasing its value shifted the

central notch frequency towards higher

frequency value. Similarly when increasing

the T2 value the centre notch frequency

shifted towards lower values and decreasing

the T2 value shifted the centre notch

frequency value towards higher frequency

values. Optimization of these values is

obtained by varying these values.

The parameters U1 and U2 significantly

controls the lower WLAN notched band. The

optimized values for the U1 and U2 are

obtained to be 7mm and 2.6mm. Increasing the

U1 and U2 value shifts the centre frequency

towards lower values of frequency and

increasing these parameters shifts the centre

frequency towards the higher values of the

frequency. The final design parameter

specifications are as follows: T1 = 6mm, T2 =

7mm, U1 = 7mm, U2 = 2.6mm, Ut = 0.2mm

(Thickness of U-shaped strips), Tt = 0.8mm

(Thickness of T-stub), h = 9.9mm, Uh = 6mm

(distance of the U-shaped strips from the

bottom), hh = 2mm.

Fig. 6. VSWR plot with dual notched bands in case of final integrated design.

The Fig. 4, 5 and 6 shows the VSWR plot

when only T-stubs, only U-shaped parasitic

strips and when both the T-stub and U-shaped

strips are present.

From results obtained through the

simulation, it is clear that the antenna

characteristics are highly dependent on the

thickness of the substrate material and it

affects the width of the feed line in order to

obtain desired bandwidth impedance of 50Ω.

The proposed metal for the patch and ground

planes is annealed copper and its thickness

during fabrication will be 0.018mm. The

fabricated antenna has the frequency range

from 2.7 to 9.6 GHz with VSWR < 2,

covering the entire UWB band with dual

notched band of 3.2–3.9 GHz and 5.14–5.45

GHz, respectively.

In addition, the comparisons for

several different dual-notched-band UWB

antennas are studied. Compared to [6] and

[8], the proposed UWB antenna with dual

notched bands has better band-notch

characteristics and when compared to that

of the [11] the cost of the substrate is

considerably low and hence it commercially

efficient. And in it the band notch is for the

entire 5-6 GHz of bandwidth which causes

loss of data in between the upper and lower

WLAN frequency bands. But this proposed

design notches only the lower WLAN

bandwidth.

III. CONCLUSION

In this paper, a monopole printed antenna is

presented analyzed and designed for

operation in the UWB bandwidth range.

Adjusting the gap between the radiation

patch and partial ground plane, a wide

impedance bandwidth is obtained. Moreover


I. Benjamin

this antenna is proposed to be fabricated on

FR-4 substrate and hence the design

parameters have been reconfigured

accordingly. Hence this antenna is much cost

efficient than those which are present earlier

as they were fabricated in Rogers 4003

substrates [11] which is much costlier than

FR-4 substrate. Thus the total fabrication cost

of the design increases considerably.

By implementing a T-shaped stub in the

rectangular radiation patch and a pair of U-

shaped parasitic strip elements besides the

feed line, dual stop bands for applications

of WiMAX and lower WLAN are

achieved. The interference of the WiMAX

and the lower WLAN applications in the

desired UWB range for applications using

this antenna is appreciatively reduced and

performance is desirably obtained.

The radiation pattern of this antenna

shows good omni-directional performance

throughout the UWB frequency range and

good gain in the UWB band is obtained.

Accordingly, the proposed antenna is

expected to be a good candidate in various

UWB systems.

REFERENCES [1] I. Oppermann, M. Hamalainen, and J. Iinatti,

UWB Theory and Appli- cations. New York: Wiley, 2004, ch. 1, pp. 3–4.

[2] S. R. Branch, “Band-notched elliptical slot

UWB microstrip antenna with elliptical stub filled by the H-shaped slot,” J. Electromagn. Waves Appl., vol. 22, pp. 1993–2002, 2008. [3] Y. J. Cho, K. H. Kim, D. H. Choi, S. S. Lee, and

S. O. Park, “A minia- ture UWB planar monopole antenna with 5-GHz band-rejection filter and the time-domain characteristics,” IEEE Trans. Antennas Propag., vol. 54, no. 5, pp. 1453–1460, May 2006. [4] Y. C. Lin and K. J. Hung, “Compact ultra-

wideband rectangular aperture antenna and band-notched designs,” IEEE Trans Antennas Propag., vol. 54, no. 11, pp. 3075–3081, Nov. 2006. [5] K. H. Kim and S. O. Park, “Analysis of the small

band-rejected antenna with the parasitic strip for UWB,” IEEE Trans. Antennas Propag., vol. 54, no. 6, pp. 1688–1692, Jun. 2006. [6] J. Liu, S. Gong, Y. Xu, X. Zhang, C. Feng, and N.

Qi, “Compact printed ultra-wideband monopole antenna with dual band-notched characteristics,” Electron. Lett., vol. 44, no. 12, pp. 710–711, Jun. 2008. [7] M. Abdollahvand, G. Dadashzadeh, and D.

Mostafa, “Compact dual band-notched printed monopole antenna for UWB application,” IEEE Antennas Wireless Propag, Lett., vol. 9, pp. 1148–1151, 2010. [8] Q. X. Chu and Y. Y. Yang, “A compact

ultrawideband antenna 3.4/5.5 GHz dual band-notched characteristics,” IEEE Trans. Antennas Propag., vol. 56, no. 12, pp. 3637–3644, Dec. 2008. [9] C. Y. Hong, C. W. Ling, I. Y. Tarn, and S. J.

Chung, “Design of a planar ultra-wideband antenna with a new band-notch structure,” IEEE Trans. Antennas Propag., vol. 55, no. 12, pp. 3391–3396, Dec. 2007. [10] J. Jung, W. Choi, and J. Choi, “A small

wideband microstrip-fed monopole antenna,” IEEE Microw, Wireless Compon. Lett., vol. 15, no. 10, pp. 703–705, Oct. 2005. [11] Wen Jiang and Wenquan Che, ”A Novel UWB

Antenna With Dual No-tched Bands for WiMAX and

WLAN Applications”IEEE Antennas and Wireless

Propagation Letters, vol.11, pp. 1536-1125, 2012.


Mr.Manoranjan Kumar, Ms. Divya.P.K

SMART WEARABLE OBSTETRIC ASSISTANT

AND REMINDER

Mr.Manoranjan Kumar Ms. Divya.P.K

Department of ME Department of ME

MVJCE ,Bangalore MVJCE,Bangalore

Abstract—The purpose of this project is to

design a smart system that uses noninvasive

techniques in recording the frequency and

duration of labor pain during pregnancy so

as to assist the expectant person in

determining the time when she must start

from home to go to the hospital and for

how long the doctor can safely delay the

delivery after arriving at the hospital.

There are various other difficulties faced by

the women during pregnancy. Here we

wish to outline few of these difficulties and

through this project we would try to suggest

few remedies for them. The device will be

synchronized with the concerned doctors

system using the concept of Tele-medicine

and thus it will provide the user with a

friendly interface through which the

exchange of important information can

occur between the user and the doctor at

several instances during the gestation

period. The device will also measure the

pulse rate and the temperature of the user’s

body and regularly update the information

to the doctor’s system which can be

analyzed for any abnormalities. We also

have the GSM modem embedded in the

system that can send various indications

such as emergency, panic, slip/fall etc., in

the form of a text message onto the

expectant women husband or on any other

family member’s number as fed in the

system so that they can aid her in case of

need. It will also aid in calling for an

ambulance service in case of emergency.

With the help of the GPS antenna used in

the device we can also be able to track the

location of the user on the Google maps

application. Apart from being used by the

women during the pregnancy, this device

can be used by old-age people for similar

problems such as emergency, panic, fall,

temperature and pulse rate measurement,

etc.

Keywords- Pregnancy, Tele-medicine,

gestation period, GSM modem, GPS

antenna, Google maps application.

I. INTRODUCTION

In the past few decades we have witnessed a

rapid growth in the field of science and

technology, and evidently there has been a

tremendous advancement in the Health Care

Systems. Technology now provides us with

various innovative methodologies to carry

out the most complex operations in a simple

and sophisticated manner. Few such

methodologies in the field of health-care

include wearable technology like Google

glass, Optogenetics, Digestible sensors,

Tele-medicine, Intra-operative surgeries, etc.

Due to busy lifestyle and different

sort of involvements in today’s world, it is

difficult to commune frequently from one

place to another. Pregnancy is an important

phase in a woman’s life. During these 9

months gestation period, she may have to get

routinely checked up by the doctor. This

check up might be as often as every 15 days.



Considering the difficulties that might be

faced by a woman in taking an appointment

from the doctor and in travelling all the way

to hospital, we try to design a smart system,

that will avoid unnecessary travelling of the

pregnant woman to the hospital, by using the

concept of Tele-medicine.

Tele-medicine is defined as the

delivery and sharing of medical information

of patient over a distance using

communication over networks. Thus, using

this concept the distance barrier between the

doctor and the patient can be reduced.

Existing Tele-medicine systems only

exchange the information in the real time

with fixed location, or with a bounded

location or pre-configured location. Using

portable devices, Tele-medicine service is

feasible even on the move.

We propose a wearable mechanism

that would be preferable when the user is

actively working or when he/she is on the

move. The system is designed using less

expensive and user friendly components, as

will be discussed in the following sections.

II. BLOCK DIAGRAM

Block diagram is as shown in the above

figure. The device is intended to perform

different kind of functions. It involves a

number of hardware parts which are

operated in a sophisticated manner using the

software’s developed for the respective

purposes.

The hardware and the software parts can be

listed as follows:

Hardware Part:

PIC 18 Microcontroller

GPS Modem

GPS Antenna

GSM Modem

1:2 MUX

Antenna

GPS

MODEM

Antenna

GSM

MODEM

Multiplexing

Logic

Keypad for Distress

switch Pressing

1. Pain

2. Pain Intensity

3. Emergency

4. Cancel

Microchip’s

8 Bit Micro-

Controller

PIC18

LCD

Pulse

Counter

Accelerometer

2 Axis

ADC 0809 National

Semiconductor

Temperature

LM35

Buzzer

PC with

VB6

with

Google

API

Runnin

g

Antenn

a

GSM

MODE

M



Software Part:

PIC 18 Embedded C coding for

MPLAB

Visual Basic6 for the GUI on the

front end of the system.

Google Map API connectivity.

We are making use of a PIC18

microcontroller. It has various advantages

over the low cost 8051 microcontroller and

the most expensive Raspberry Pi. Few

advantages can be listed out as follows,

It is inexpensive,

Has built in oscillators,

Has a small instruction set to learn,

Allows for wide range of interfaces

including SPI, USB, USART, A/D,

etc,

Availability of processors

in DIL package makes them easy to

handle for hobby use.

The pin diagram and the block diagram of

the PIC 18 microcontroller is as shown in the

following figures,

Figure 1: PIC Microcontroller

Figure 2: Pin diagram of PIC 18 Microcontroller

Figure 3: Block diagram of PIC 18 Microcontroller

III. WORKING

The following are the components and their

use in our design:

1. The accelerometer is used for fall

detection. This device basically

measures the deviation angle from

the free fall direction. If the direction

of the axis of the device is

perpendicular to the ground, the

deviation will be 0. Fall can be

detected whenever there is a

deviation measured.

2. LM35 temperature sensor is used to

measure the temperature of the user’s

body. This will be an analog input

which will be converted into digital

information using the ADC and

further transferred to the doctor’s

system through GSM.

3. Pulse counter is used to check for any

deviation in the heart rate which is

resulted from any abnormality in the

body.

4. LCD is used to display the text

messages sent from the doctor. This

can also be used to indicate the

medicines prescribed by the doctor,

any changes to be done in the

dosages, alarm about the exercise

timings, etc.



5. There can be a BUZZER which can

indicate the people around the user in

case the patient is in a panicky situation.

6. The GPS modem helps in locating the

user on the map. If the user is in a trouble

and is not in a condition to contact any

family member, in such cases, on just

one key press the pre stored message

along with the location of the user is sent

to one or more of her family members.

7. The GSM modem is used to

communicate with the dear ones over the

network of their phones. Any messages

to be sent by the user, in case of need,

panic or any emergency can be sent over

by using the GSM modem. This also aids

in calling an ambulance in emergency

situation.

IV. APPLICATIONS

1. Periodic recording and transfer of the

users information:

As indicated by the block diagram, the

device will include a pulse counter and a

temperature sensor.

These devices will measure the pulse rate

and the temperature respectively, of the

user. This information is then sent on to

the doctor’s system by employing the

Tele-medicine concepts.

2. Reminder about the medications:

The device will also have a LCD display,

thus the doctor can transfer information,

such as the medicines to be take, dosage

of the medicines, time of consumption of

that medicine, etc. This feature is of great

importance when the patient has to be

prescribed a different medicine after a

certain amount of time. For example,

during the first few months of pregnancy

folic acid dosage is prescribed, later this

medicine is changed to a different one.

3. Important messages from the doctor:

Many a times it becomes urgent to inform

the pregnant woman about the

appointments with the doctor, and

sometimes about the tests to be

conducted. At such times the doctor can

immediately send an SMS to the mother.

Since it is a wearable device the message

is always flashed on the on-board LCD

screen and goes away only when the

“Message Seen” Button is pressed.

4. Reminder about the exercises:

During the Pregnancy the mother has to take

care of her body so that she is fit and

ready for the final day. Further the body

generates a lot of aches and pains during

the term of pregnancy. To ease all these

pains the mother has to do a lot of yoga

and stretching exercises which needs to

reminded to be done at predefined

timings. The system can be used to

remind the same.

5. Indicating when the Pregnant woman

needs to start moving to the hospital:

As we all know, timing of labor pain is of

great importance in indicating the proper

time of delivery and is relied upon to a

great extent in determining when the

pregnant woman should start moving to

the hospital and for how long the doctor

may safely delay the delivery after

arriving at the hospital . By accurately

determining the frequency and duration

of the labor pains the expectant mother

can be prevented from admitting in a

hospital too much in advance based on

some false indications. The timing of

these pains is also important in the labor

room, for various reasons.

The standard rule in the hospitals

seems to be that, the expectant mother

tells the nurse when she experiences a



pain and the nurse makes a written note

of the time of occurrence of the recurrent

pains. In this manner the progressive

shortening of the period between pains is

ascertained. If the doctor is not present at

the hospital at that time then he will be

informed that the delivery is approaching

and needs his attention. But, the nurse is

not always at hand when the pain recurs

and sometimes due to some disturbance,

the pattern of frequency of the pains is

interrupted and it may become

insignificant to some extent. An

experienced nurse can detect the periodic

contraction of the uterus by placing her

hand over the abdomen of the patient, but

this method requires that the nurse be

present by the side of the patient at all the

times. Due to these difficulties we

propose the use of the contraction timer

calculator, which basically consist of a

indicative scale with switches, that will

act as a programmable stop watch and

will need the patients input to note the

time between the contractions and the

intensity of the pain. Depending on this

measurement, the device will indicate if

it is the time to move on to the hospital.

6. Any distress to be informed to the nearby

people:

Any kind of breathlessness, heaviness in the

stomach might also start cramps and

might pose difficulty to call. In such

cases a simple switch press might be able

to start a Buzzer.

7. Automatic ambulance to be called in case

of emergency:

In case of acute emergencies, the press of a

button may enable the message or call to

be made for requesting the service of

ambulance at the present location of the

user.

8. Automatic SMS to be sent with location

in case of emergency:

Detection of a fall as will be defined later or

on a press of a switch or the body

temperature going above the normal or

pulse count irregularities will all initiate

an SOS SMS which can be used to call

and alert an Ambulance. The SMS may

also be sent to any of the family

members of the user indicating that the

user is in some sort of emergency.

9. Fall detection in case of a slip.

Any accidental slips of mother can cause

major accidents, which may even lead to

involuntarily termination of pregnancy;

sometimes it can even be fatal for mother

and the child. In such cases, using an

Accelerometer, the tilt of the body can be

detected which can indeed indicate the

fall. Immediate attention may save the

mother and the child from the dangers.

10. Mapping the location of the user on the

map with relevant details.

The system will employ another GSM

MODEM connected to the Google Map

where the exact co-ordinates of the

mother can be located. The information

from the GPS will then be transferred in

the NMEA format to the Base station

(which might be at Home/ Police Station/

Hospital etc) (some predefined Numbers)

so that the information can then be

mapped on the Google Earth and the

approximate location can directly be

obtained on a real time Map. For this we

will be using the Google Map API on

which we will be able to plot the real

time location of the user.

V. EXPERIMENTATION AND

TESTING

1. The model is tested by using a webcam

of 5MP resolution.



2. MATLAB proves to be a very good tool

in extracting the features and in

classifying the emotions. The

development of the MATLAB code was

also easy when compared to the

development in any other image

processing software.

3. Capturing of the video and extraction of

the expression is found to be working

well. But, since it is designed to work in

real time, the model does not provide us

with 100% accuracy.

4. The device was also experimented with

the pre recorded video as the input. Even

in this case the same procedure was

carried out for the extraction of emotion,

classification and transmission. When

tested with numerous trails, the

classification is found to be nearly 100%

accurate.

5. The transmission of the serial codes and

the operations over the home automation

model does work to a very accurate level,

once the correct expression is detected.

6. The current model that has been

developed is made to play one song for

every emotion. This song is stored into

the database, by the user. In case of

android profiling, any one song on the

android device can be chosen to be

played, as required by the user.

7. The autism rehabilitation application

works well in training the patients. The

training accuracy is dependent on the

subject, i.e. the user. The level of

understanding of the user and the stage of

this abnormality will also affect the

efficiency of the application. Thus, the

efficiency of working of the application

cannot be determined quantitatively.

8. The drowsiness detection is also

subjective to various restrictions. The

plot will usually be wearing a Head gear.

This may cause interruption in capturing

the image of the pilot’s face. Once

captured, the processing of the image and

working of the alarm poses no much

complication.

Figure 3: Working model

VI. CONCLUSION The developed system helps a pregnant

woman in communicating with her

consulting doctor easily and effortlessly.

Unnecessary cost of staying over at the

hospital before the time that the delivery

is due can be avoided. It may help us to

prevent any adverse situations from

occurring in the course of pregnancy.

VII. REFERENCES [1] Dr. Conrad Zapanta , Kenneth Varner,

Android based tocodynamometer and fetal heart

rate monitor, Carnegie Mellon University press.



[2] Orlin Patric O Brien, Intrauterine muscle

activity measuring system, United States Patents.

[3] Yusimi Sobrino Bonilla,T Caring for

Laboring Women with Amyotrophic Lateral

Sclerosis: A case report, The American

Journal of Maternal/Child Nursing(2004)

[4] Simpson KR, The context and clinical

evidence for common nursing practices during

labor, asrn.org(2005).

[5] Mazidi, Pic Microcontroller and Embedded

Systems: Using Assembly And C For Pic 18,

Pearson education, 2009

[6] Ahmed Al-Rabbany, Introduction to GPS:

The Global Positioning System, Artech House,

2002.

[7] Asha Mehrotra, GSM system engineering,

Artech House, 1997.


Mrs. Aruna Dore

STUDY OF COLOR AND GRAY IMAGE

DENOISING USING DIFFERENT FILTER

TECHNIQUESMrs. Aruna Dore

Department of Telecommunication Engineering

MVJ college of Engineering, Bangalore, India

Email id: [email protected]

Abstract— Image is a collection of

information and the occurrence of noises

in the image causes degradation in the

quality of the images. So the information

associated with an image tends to loss or

damage. It should be important to restore

the image from noises for acquiring

maximum information from images. As a

remedy, the quality and the information

from the noised image can be retrieved

using different types of filters such as

Gaussian Filter, Mean Filter, Median

Filter etc. In this paper, how different

types of noise (Gaussian, salt and pepper

noise) will affect the quality of the images

and the information in it is studied and

image de-noising is performed for different

noise by Mean filter, Median filter and

Wiener filter . Further results have been

compared for all noises using MATALAB

Software.

Keywords—Image Processing, Gaussian

filter, Mean Filter, Median filter, noise

I. INTRODUCTION

Image denoising is one of the most

important concepts in digital image

processing. It is widely used in various

image related applications like, Magnetic

Resonance Imaging [MRI] analysis, 3-D

object detection etc. The digital images

contain some degree of noise. The goal of

image denoising is to restore the details of

an image by removing unwanted noise.

Noise may be classified as substitutive noise

(impulsive noise: e.g., salt and pepper noise,

random valued impulse noise, etc.), additive

noise (e.g., additive white Gaussian noise)

and multiplicative noise (e.g. speckle noise).

In this work different types of noise such as

salt & pepper, Gaussian noise, poisson noise

& speckle noise are considered. There are

different methods of removing noise from

original image. In common there are two

types of image denoising model, linear

model and nonlinear model. Linear model

[2] are being considered for image

denoising, the main benefits of using linear

noise removing models is the speed and the

limitations of the linear models is the models

are not able to preserve edges of the images

in an efficient manner. Non-linear models

[3] can preserve edges in a much better way

than linear models but very slow. The main

aim of noise removal scheme is to suppress

noise as well as to preserve details and edges

of image as much as possible. Figure [1]

shows the basic model for denoising of

image.

In this model first image is taken and some

noise is added to image to make it as noisy

image and then noisy image is decomposed

by applying different filter to decomposed

image to remove noise from noisy image

and at last denoised image is obtained. The

performance parameter between the noisy

image and denoised image can be calculated

in terms of Peak Signal Noise –Ratio

(PSNR) and Root Mean Square Error

(RMSE).


Mrs. Aruna Dore

Figure 1: Basic model for Denoising Image

II. DIFFERENT TYPES OF FILTERS

A. Median Filter

Median filtering [1] is a nonlinear method used to remove noise from images. Widely used method to preserve edges. It is particularly effective at removing salt and pepper noise. Median filter works by moving through the image pixel by pixel, replacing each value with the median value of neighbouring pixels. The pixel is calculated by first sorting all the pixel values from the pattern of neighbours into numerical order, and then replacing the pixel being considered with median pixel value. Median filter is better able to remove noise without reducing the sharpness of the image.

B. Mean Filter

Mean filter is type linear filtering scheme.

Mean filter is also known as averaging filter

[1]. The Mean Filter applies mask over each

pixel in the signal. Each of the components

of the pixels comes under the mask are being

averaged together to form a single pixel

that‟s why the filter is otherwise known as

average filter. Edge preserving criteria is

poor in mean filter. Mean filter is defined by

Mean Filter

…………….. (1)

Where (x1 ….. xN) is image pixel range.

Mean filter is useful for removing grain

noise from the photography image. As each

pixel gets summed the average of the pixels

in its neighborhood is found out, local

variations caused by grain noise are reduced

considerably by replacing it with average

value.

C. Wiener Filter

The main aim of the Wiener filter is to filter

out the image that has been corrupted by

noise. Wiener filter is based on a statistical

approach. Desired frequency response can

be acquired using this filter. Approaches

followed by wiener filtering are of different

angle. For performing filtering operation it is

must to have knowledge of the spectral

properties of the original signal and the

noise, in achieving the criteria one can get

the LTI filter whose output will be as close

as original signal as possible. Wiener filters

[1] possess characterized by the following:

a. Assumption: signal and (additive) noise

are stationary linear random processes with

known spectral characteristics.

b. Requirement: the filter must be causal

where this requirement is failed it resulting

in a non-causal solution Periodic noise can

be effectively removed by correcting the

amplitude spectrum components altered by

the noise, and two frequency filtering

methods are currently available, i.e., Wiener

filtering and notch filtering. However, a

Wiener filter requires an accurate noise

model, which may be difficult to obtain in

various practical cases. In addition, a Wiener

filter is also complicated in computation.

D. Gaussian Filter

The Gaussian filtering scheme is based on

the peak detection. The peak detection is

based on the fact that peaks are to be

impulses. The key point is that this filter

corrects not only the spectral coefficient of

interest, but all the amplitude spectrum

coefficients within the filter window. Some

properties of Gaussian filter are [2]:

1. The weights give higher significance to

pixels near the edge (reduces edge blurring).

2. They are linear low pass filters.

3. Computationally efficient (large filters are

implemented using small 1D filters).

4. Rotationally symmetric (perform the same

in all directions).

5. The degree of smoothing is controlled by

σ (larger σ for more intensive smoothing).

III. IMAGE NOISE

Noise in images is caused by the random

fluctuations in brightness or color

information. Noise represents unwanted

information which degrades the image

quality. Noise is defined as a process which

affects the acquired image quality that is


Mrs. Aruna Dore

being not a part of the original image

content. Digital image noise may occur due

to various sources. During acquisition

process, digital images convert optical

signals into electrical one and then to digital

signals and are one process by which the

noise is introduced in digital images. Due to

natural phenomena at conversion process

each stage experiences a fluctuation that

adds a random value to the intensity of a

pixel in a resulting image. In general image

noise is regarded as an undesirable by-

product of image capture. The types of

Noise [2] are following:-

• Amplifier noise (Gaussian noise)

• Salt-and-pepper noise

• Shot noise (Poisson noise) • Speckle noise

A. Gaussian Noise

Gaussian noise is statistical in nature. Its

probability density function equal to that of

normal distribution, which is otherwise

called as Gaussian distribution. In this type

of noise, values of that the noise are being

Gaussian-distributed. A special case of

Gaussian noise is white Gaussian noise, in

which the values always are statistically

independent. For application purpose,

Gaussian noise is also used as additive white

noise [6] to produce additive white Gaussian

noise. Gaussian noise is commonly defined

as the noise with a Gaussian amplitude

distribution, which states that nothing the

correlation of the noise in time or the

spectral density of noise. Gaussian noise is

otherwise said as white noise which

describes the correlation of noise. Gaussian

noise is sometimes equated to be of white

Gaussian noise, but it may not necessarily

the case.

B. Salt and Pepper Noise

Salt & Pepper noise mode [4], there is only

two possible values „a‟ and „b‟. The

probability of getting each of them is less

than 0.1 (else, the noise would greatly

dominate the image). For 8 bit/pixel image,

the intensity value for pepper noise typically

found nearer to 0 and for salt noise it is near

to 255. Salt and pepper noise is a

generalized form of noise typically seen in

images. In image criteria the noise itself

represents as randomly occurring white and

black pixels. An effective noise reduction

algorithm for this type of noise involves the

usage of a median filter, morphological

filter. Salt and pepper noise occurs in images

under situations where quick transients, such

as faulty switching take place. This type of

noise can be caused by malfunctioning of

analog-to-digital converter in cameras, bit

errors in transmission, etc.

IV. SIMULATION RESULTS

Different Image Noise Characteristics for Color and Gray Image:

(a) Original Color Image

(b) Image affected by Salt and Pepper noise


Mrs. Aruna Dore

(c) Image affected by Gaussian noise

(d) Original Gray Image

(e) Image affected by Salt and Pepper noise

(f) Image affected by Gaussian noise

Figure 2: Image affected by different types of noise

Figure 2 (a) represents the original image

being taken for experimental purpose. Figure

2 (b) represents the image being affected by

Salt and Pepper noise for color image.

Figure 2(c) represents the image affected by

Gaussian noise for color image. Figure 2 (e)

represents the image being affected by Salt

and Pepper noise for gray image. Figure 2

(f) represents the image being affected by

Gaussian noise for gray image. The above

results shows Noise in images causes

degradation in image quality. So the

information associated with the images is

damaged and it is must to restore the image

from noises for acquiring maximum

information from images. As a remedy, the

quality and the information from the noised

image can be retrieved using different types

of filters.

(a) Salt and Pepper noised image is filtered

by Wiener Filter

(c) Gaussian noised image is filtered

by Wiener Filter


Mrs. Aruna Dore

(e) Salt and Pepper noised image is filtered

by Mean Filter

(b) Salt and Pepper noised image is filtered

by Median Filter

(d) Gaussian noised image is filtered

by Median Filter

(f) Salt and Pepper noised image is filtered

by Median Filter

(g) Salt and Pepper noised image is filtered

by Wiener Filter

(h) Gaussian noised image is filtered

by Mean Filter

(i) Gaussian noised image is filtered

by Median Filter

(j) Gaussian noised image is filtered

by Wiener Filter


Mrs. Aruna Dore

Figure 3:Denoised Image by different types of Filters

IV. CONCLUSION & FUTUERE WORK

In this paper two types of noises (Salt and

Pepper, Gaussian) had been added to the

original image and observed that all noise

causes degradation in the image quality

which results in loss of information. The

denoising of degraded image is performed

using Wiener, Mean and Median filter. From

the simulation results its confirmed that

Median filter works well for Salt and Pepper

noise than Mean and Wiener filter whereas

Wiener filter works well for removing

Gaussian compared to that of Mean and

Median filter.

In Future this test can be performed on

different other noises and performance

parameter between the noisy image and

denoised image can be calculated in terms of

PSNR and RMSE.

REFERENCES

[1] Rafael c. Gonzalez and Richard E. Woods,

“Digital Image Processing,”. third edition.Prentice-Hall ,Englewood,Cliffs,NJ.2001.

[2] Charles Boncelet, “Image Noise Models” in Alan C.Bovik, Handbook of Image and Video Processing, 2005.

[3] Astola, J., Kuosmanen, P., “Fundamentals of Non-linear Digital Filtering”, CRC Press, NewYork, Boca Raton, 1997.

[4] Changhong Wang, Taoyi Chen, and Zhenshen Qu, “A novel improved median filter for salt-and-pepper noise from highly corrupted images”, IEEE 2010, pp. 718-722.

[5] Shu-tao LI, Yao-nan WANG, “Non-Linear Adaptive Removal of Salt and Pepper Noise from Images” , Journal of Images and Graphics, Vol. 5(A), No. 12, Dec 2000.

[6] JianhuaLuo, Yuemin Zhu, and Isabelle E. Magnin, “Denoising byAveraging Reconstructed Images: Application to MagneticResonance Images”, IEEE transactions on biomedical engineering,vol. 56, pp 666 - 674 , March 2009.

[7] KrishnanNallaperumal,JustinVarghese,S.Saudia,K.Krishnaveni,Sri.S.Ramasamy,Santhosh.P.Mathew,P.Kumar “An efficient Switching Median Filter for Salt & Pepper Impulse Noise Reduction”, IEEE 2006, pp. 160-166.


Mr. Prashant S Ghulappanavar , Ms. Kavya B M

A SURVEY ON HUMAN SENSING

APPLICATIONS USING UWB RADAR

Mr. Prashant S Ghulappanavar Ms. Kavya B M

MVJCE Bangalore, India VVCE Mysore, India

[email protected] [email protected]

Abstract— Ultra wideband (UWB)

technology has become a very popular topic

in industry and academia. UWB signals have

an excellent spatial resolution and good

penetration into many materials which

makes them very interesting for radar

applications [04]. The paper [02] covers the

two important parameters related to the

“through the wall imagery” which include

quality and reliability. The smears and the

flaws in the walls may produce a blur image

or may shift the imaged target position. An

auto focusing technique based on higher

order statistics corrects errors under

unknown walls. The paper [01] describes the

use of the finite difference time domain

method to investigate the capabilities and

limitations in the use of radar system to

determine the human model target inside the

realistic room.

Keywords- UWB, “through the wall

imagery”, back projection, Auto focusing,

high-order statistics.

I. INTRODUCTION

The UWB radar system is used for scanning of the objects behind a wall. An electromagnetic wave is transmitted via antenna system, penetrates through the Wall, it is reflected by the investigated object. The UWB radar has been used in several applications which include military applications low altitude missile detection, minefield detection etc. The radio waves have inherent capability to penetrate and detect the target on the other side of the wall. A time pulse of 0.8 ns at a center frequency of about

1.1 GHz is used. The performance of the UWB radar is the examined by taking the 2 dimensional images of a room with the human body model included. This is done by considered by the data given by the monostatic scenarios radar scenarios where the responses are collected and processed by using by time domain back projection method.

II. ROOM AND UWB RADAR COMPUTER

MONITORING

The electromagnetic phenomenon involving the illumination of the realistic room environment by UWB radar is modeled using the FDTD method [01].

A. Room Geometry

The room used in the experiment is made up of brick walls, concrete floor, and wooden ceiling .the components in the room include water pipes, metallic electrical outlets, water conduits, metallic barred window. A computer aided design (CAD file) of the room is sketched using AutoCAD.

Figure 1. 3D view of the modeled room and its

components



The paper [01] specifies for the accurate electromagnetic interaction with the geometries of the room the physical parameters of the materials analyzed thoroughly. These physical parameters are the electrical conductivity and electrical permittivity. Table below lists the parameters at the center frequency fc = 1.1 GHz.

Material Conductivity Permittivity

Brick 0.001 s/m 4.44

Concrete 0.015 s/m 15

Wood 0 5

Glass 0 5

Plastic 0 5

Metal 58000000 -

Table 1. Parameters of materials in the modeled room

B. Radar Modeling

In the paper [01], mono-static configuration is used, where single Antenna element is used for transmitting and receiving the pulses. In case of mono-static configuration, prior knowledge of the object angle to the antenna plane is not necessary for determining distance of the object, this is suitable for determination of buried objects inside another material. Mono-static configuration is reduced in size, and suitable for antenna array.

C. UWB Excitation Pulse

To model the EM illumination of the modeled room and its contents with an UWB short pulse, the transmitter dipole antenna is fed by a 0.8 ns Gaussian pulse modulated by a 1.1 GHz sine wave below show the figure of time and frequency response of the UWB pulse Figure 2.

Figure 2. Time and frequency response of UWB

excitation pulse using simulation

III. HUMAN PHANTOM

MODEL

To include a human subject in modeling [01], a human phantom model is imported into the FDTD simulation space. Below Figure 3 shows the model geometry of the human body model standing inside the modeled room. The FDTD meshed geometry of the human body consists of twenty three tissue groups representing most of the anatomical human body organs and tissues. Then each of these twenty three material groups is assigned a material density (kg/m3), conductivity (s/m) and relative permittivity .these physical parameters are frequency dependent and their values are set for fc = 1.1 GHZ, the center frequency of the UWB pulse used.

Figure 3. Human model inside the room with the

radar setup dimensions and location in front of the room



IV. LIFE DETECTION SYSTEM

The paper [03] presents the life detection system. The main component is bi-static continuous wave (CW) radar consisting of a local oscillator which produces a sinusoidal signal of 10.45 GHz, a low noise amplifier, and a two patches array as transmitting antenna. The radar irradiates an electromagnetic wave and collects the reflected signal that contains the breathing and the heartbeat information coming from a human detected target. The backscattered signal is received by a two patches antenna, amplified and led to an I/Q detector. The orthogonal detector is mandatory because the ICA [06] requires a number of Observation points equal to the number of the original signals and we exploit I/Q signals as two independent sources of information. Then the output I/Q signals are given as input to a remote elaboration system by means of a low frequency wireless channel. As stated previously the amplitude and the phase of the received backscattered wave are modulated in accordance with the movement of breathing and heartbeat. The information associated to amplitude is generally Negligible [07] and only the phase variation is considered.

The signal at the receiving antenna can be

expressed considering the following relation.

(1)

Where ὼ0 is the angular frequency and v is

the propagation velocity of the radio waves, Ax, Aj are the amplitudes associated to life signals and rubble respectively. Rs(t) and Rj are the round trip distance of the survivor and rubble from the radar system. The second term describes the constant contributes due to the rubble and it can be easily removed with a simple filtering procedure while the first term contains information related to life-signals. The small movement of the survivor body caused by breathing and heartbeat can be seen as a fluctuation around a mean distance Rs and modeled at the output of the orthogonal phase

detector as ‘x (t) = (ὼ0 v (Rs + Ab cos(ὼbt) + Ah cos(ὼht))), where ὼb and ὼh are the frequencies due to the breathing and the heartbeat respectively. Ab, Ah are the amplitudes due to the movement of the chest and heart respectively.

The weak received backscattered field, which is a mixture of vital signals, noise and clutter contribute, is amplified down-converted with an orthogonal detector, and processed with an analog-to-digital converter. The I/Q signals at the output of the orthogonal detector are led to a remote elaboration unit by means of a low frequency transmission module. The received signals must be post-processed to separate the life signals from the noise and the clutters contribute. ICA algorithm has been chosen to accomplish this task. The ICA is a method for separating mixed data (such as MRI images [08], biomedical data [09], sounds, Telecommunication channels or signals into underlying informational components.

The ICA belongs to a class of methods called blind sources separation (BBS). The classical example is two people speak at the same time in a room. Two microphones, placed in different points inside the room collect a mixture of the two voice signals. From these two signal mixtures, ICA can recover the two original source signals. One of the most important facts about standard BSS methods like ICA is that the number of independent source of information (i.e., the receivers) must be greater than the number of overlapped source signals. For the problem at hands this implies that there must be at least two probes to detect the life signals and for this reason we use an orthogonal detector generating EI and EQ these two signal mixtures collected at the output of the orthogonal phase detector and sent to the remote elaboration system for the post-processing could be expressed

= (2)



Figure 4. Diagram of the life detection system.

where EI (t) = AI cos('x(t))+N(t) and EQ(t)

= AQ cos('x(t))+N(t) represents the noise contribution due to the clutter and other interfering sources. The terms a11, a12, a21, and a22, are parameters that depend from the phase shift. The two original signals N(t) and 'x(t) are assumed to be statistically independent at each time instant: for this reason it is possible to estimate the original signals processing the mixed signals EI (t), EQ(t) observed at the orthogonal detector.

Let us consider the following matricial representation

(3)

After estimating the coefficients matrix [A] and its inverse [A]¡1, it is possible to obtain the original signals as shown in the following equation

This goal is accomplished by using the ICA

algorithm. After the ICA application, the cleaned signals N(t) and 'x(t) are separated. Only ‘x(t) contains information related to the weak life signal while N(t) is negligible. ‘x (t)

is then further processed with a FFT algorithm in order to estimate the heartbeat and the breath rate.

Figure 5. Photography of the experimental setup.

V. ULTRA WIDE BAND STTW

[SEE THROUGH THE WALL]

In paper [05], the long term goal of military field imaging technology is the rapid detection of enemies' maneuvering; through acquiring relatively high-resolution images using advanced multidimensional image processing, pattern recognition techniques, and fast data processing. An example block diagram of such a radar system, developed at the University of Tennessee, is shown in Fig. 6. The system consists of an RF T/R board, UWB antennas, a digital timing and control board, and an imaging processing software module [10]. Capturing the data is the most challenging task for a system with a 1 GHz bandwidth, as Nyquist's sampling theorem requires a sampling rate of over 2 GS/s. In order to resolve distances on the order of one centimeter, rates exceeding 10 GS/s are required. Individual components at these rates are either not yet offered or very expensive. Hence, field programmable gate-arrays (FPGA)-based system was developed here, to implement a hybrid sampling scheme using Real-time and equivalent-time sampling techniques. Where, for a 10 MHz radar pulse repetition rate, the waveform is digitized at a 100 MHz rate. 10 samples are taken during each cycle, and then a 200 ps delay is placed



on the ADC triggering signal for the next 10 samples. The total time to collect the data comes out to 100 x 50 ns, i.e. 5 Fts. In general, intense wideband signal processing would normally require an entire custom VLSI or an ASIC implementation. After taking redundancy into account, this system achieves a 2.4ms/frame rate, with an averaging factor of 8 to improve S/N ratio. FPGA-based equivalent time sampling and control network provides a low-cost and high- performance solution for a practical UWB radar system. For image formation, algorithms such as back projection methods can be used given that wall effects are considered.

Figure 6. Typical system block diagram for

a UWB STTW radar.

CONCLUSION

UWB radar have shown effectiveness

detecting human presence in -- applications.

UWB radar system uses a unique Pulse

Frequency Repetition (PRF) for each human

body layer. Similarly, an antenna’s position

that enables to capture the echo reflected by

human body tissue is computed. The

performance of the system depends on

sampling rate and number of antenna array

elements. It was found that sampling rates

greater than 10 GHz were required for better

classification.

For human recognition, system estimates

vital signs specifically breathing rate and

heartbeat frequency. However, the level of

breath displacement is one order of magnitude

larger than heart displacement.

As the breath rate and its intensity can

depend on the person and the situation, in

some cases the frequency of breath harmonics

are close to the frequency of the heart signal,

which makes it difficult to locate and detect,

and leads to possible confusion. Future systems seek enhance this drawback,

and go beyond to isolate subjects, map structures, and exploit signals of opportunity.

REFERENCES

[1] FDTD modelling of a realistic room for the

through the wall radar applications, Walid. A

chamma,2007 ieee,1-4244-1170-x/07

[2] Auto focusing of the through the wall imagery

under unknown wall characteristics, fauzia ahmad,

senior member ieee, moeness g.amin fellow ieee

and govindaraju, ieee transactions on image

processing,vol.16,july 2007

[3] A rescue radar system for the detection of victims

trapped under rubble based on the independent

component analysis algorithm, Progress In

Electromagnetic Research M, Vol. 19, 173181,

2011,M.Donelli.

[4] Ultra Wideband Radar for Micro Aerial Vehicles,

Dario Brescianini

[5] Through-the-Wall Radar Life Detection and

Monitoring,Victor M. Lubecke, Olga Boric-

Lubecke, Anders Host-Madsen, and Aly E.

Fathy*,1-4244-0688-9/07/$20.00 C 2007 IEEE.

[6] Lee, T. W., Independent Component Analysis:

Theory and Applications, Kluwer academic

Publishers, 1999.

[7] Chen, K. M., D. Misra, H. Wang, H. R. Chuang,

and E. Postow, \An X-band microwave life-

detection system," IEEE Trans. Biomed. Eng., Vol.

57, No. 6, 607702, 1986.

[8] Molgedey, L. and H. G. Schuster, \Separation of a

mixture of independent signals using time delayed

correlations," Physical Review Letters, 36343637,

1994.

[9] Bell, A. J., T. P. Jung, and T. J. Sejonowski,

\Independent component analysis of



electroencephalographic data," Advances in Neural

Information Processing Systems, Vol. 1, 145151,

1996.

[10] Y. Yang, S. Liu, J. Wang, A.E. Fathy, "FPGA-

Based Data Acquisition and Beam forming System

for UWB See-Through- Wall Imaging Radar,"

IEEE AP-S Intl. Symp. On Antennas and

Propagation and USNC/URSI Nat. Radio Sci.

Meeting, 2006.


Poornima R

GRAPHENE: A WONDER MATERIAL

Poornima R

Department of IEM MVJCE

Whitefield Bangalore, Karnataka, India

Abstract: Graphene, a two-dimensional

carbon allotrope, has emerged as one of the

most fascinating nano materials of the

century. Its distinct qualities have attracted

great interest in the fields of chemistry,

biology, and physics. Graphene has

stimulated interest among scientists in

various fields because of its exceptional

electronic, optical, mechanical, thermal, and

magnetic properties. The unique nature of

graphene makes it stand out and applicable

to various technologies and other purposes.

One application in particular is using

graphene’s outstanding electronic properties

for future electronic devices, possibly

replacing the silicon and indium tin oxide

used in current electronics. Computers,

computer chips, and other technological

products made from graphene will be more

flexible and will function faster because of

graphene’s transparency, light weight, and

flexibility. With modifications to graphene’s

structure and electrical properties, scientists

will be able to manufacture these new

technological appliances. However, its

applicability cannot be effectively realised

unless facile techniques to synthesize high

quality, large area graphene are developed in

a cost effective way. Considerable research

has been carried out for synthesizing

graphene and related materials by a variety

of processes.

Key Words: Graphene, electronic, silicon,

transparency, light weight, flexibility, facile.

I. INTRODUCTION

Graphene is a two-dimensional crystal of

carbon hexagonal crystal lattice. Its thickness

is equal to one atom, so that graphene belongs

to a class of nonmaterial‟s. Currently subject

of graphene taken a leading position in the

number of publications in leading international

journals in the field of surface physics and

nanosystems. This interest is due to its unusual

properties. There are several key factors that

make graphene a unique set of nanomaterials.

Despite the fact that its thickness is only one

atom, graphene is a stable form that can

maintain its crystalline structure, both in

vacuum and in a wide variety of surfaces. He

is not prone to oxidation under normal

conditions, allowing its use in air and even in

more aggressive environments. The crystal

graphene is very flexible. Carbon is a well-

known element and is contained in a great

many things in this world such as organic

materials that constitute organisms. Carbon is

an interesting element because, even if some

material is made of carbon atoms only, it can

have various morphologies and characteristics

depending on how carbon atoms bind together.

while both diamond and graphite (which is

used in pencil lead ) are made of carbon their

characteristics are different. Graphite is a layer

material and its monolayer is called garphene.

Grapheme has a honeycomb structure


Poornima R

consisting of carbon atoms. It is an ideal two

dimensional material as it is an thin as the

thickness of the monolayer atoms. When

grphene is given a round geometry , it forms a

carbon nanotube (CNT), which are nothing

more than a rolled graphene sheets. Graphene

has a large conductance, where as no other

film of this thickness is not a good conductor

of electric current. In the "Advanced

Experiments with a two-dimensional graphene

material," A. K. Geim and K. S. Novoselov

was awarded the Nobel Prize in Physics for

2010.

II. BACKGROUND

Discoveries of carbon allotropes have

punctuated scientific and technological

advances at the interface of the 2nd and 3rd

millennia. One can argue that nanoscale

science as a field has emerged at the end of the

20th century largely as a result of these

discoveries. Every decade over the past 30

years saw a new formof carbon created in a

lab, giving birth to an exponentially growing

number of studies. In 1985 Kroto, Heath,

O'Brien, Curl, and Smalley obtained fullerenes

[1]. Then, in 1991 Sumio Iijima clearly

identified carbon nanotubes within the

prepared material [2]. Finally, in 2004

Novoselov, Geim, Morozov, Jiang, Zhang,

Dubonos, Grigorieva and Firsov prepared

electrically isolated, singlelayer graphene [3].

Within extraordinary short periods of time the

seminal importance of these works was

awarded with two Nobel prizes. The 1996

Nobel Prize in Chemistry was awarded jointly

to Robert F. Curl, Jr., Sir HaroldW. Kroto, and

Richard E. Smalley “for their discovery of

fullerenes”. The 2010 Nobel Prize in Physics

was given to Andre Geim and Konstantin

Novoselov “for groundbreaking experiments

regarding the two-dimensional material

graphene”. As far back as in 1947, graphene

was predicted to have extraordinary electronic

properties, if it could be isolated. For years,

grapheme was considered an academic

material that existed only in theory and

presumed not to exist as a free standing

material, due to its unstable nature. A. Geim,

K. Novoselov, and co-workers were among the

first to successfully obtain the elusive free-

standing graphene films,4 which wasa

remarkable achievement. Thus, the 2010

Nobel Prize for Physics awarded to Geim and

Novoselov for “groundbreaking experiments

regarding the two-dimensional material

graphene” must be celebrated as recognition of

remarkable ingenuity in experimental physics.

The International Union of Pure and Applied

Chemistry (IUPAC) defines graphene as a

single carbon layer of the graphite structure,

describing its nature by analogy to a

polycyclic aromatic hydrocarbon of quasi

infinite size.5 Thus, the term graphene should

be used only when the reactions, structural

relations, or other properties of a single layer

are discussed. Previously, descriptions such as

graphite layers, carbon layers, or carbon sheets

have been used for the term graphene.

III. GRAPHENE AND ITS

PROPERTIES

The pencil hasn‟t been innovative technology

since the 19th century. But graphene, the one-

atom thick sheet of carbon that, when stacked,

forms graphite, the “lead” in pencils, may be

the key to future electronic applications.

Graphene‟s electrons have also been known to

demonstrate different phenomena, such as, the

Klein effect and the quantum Hall effect. The

Klein effect takes place when charge carriers

are able to pass right through high potential

barriers as if they were nonexistent.

Graphene‟s electrons have this potential to

pass through barriers. Graphene also

demonstrates an unfamiliar version of the

quantum Hall effect. The quantum Hall effect

is a quantum-mechanical version of the Hall


Poornima R

effect that occurs in two-dimensional electron

systems, such as graphene [2]. The Hall Effect

occurs when a magnetic field is applied

perpendicular to a thin sheet of conducting or

semiconducting material through which a

current is flowing [9]. A potential difference

will be created on opposite edges of the

conducting or semiconducting material. The

Hall effect offered the first real proof that

electric currents in metals are carried by

moving electrons, not by protons. It also

demonstrated that in some substances,

especially semiconductors, that it is more

appropriate to imagine the electric current as

positive “holes” instead of negative electrons

[9]. Graphene‟s electronic current is often

described as a current of positive holes as well.

The quantum Hall effect usually takes place in

high magnetic fields and low temperatures.

However, graphene performs the quantum Hall

effect at room temperature and at even higher

temperatures; this is due to the unusual nature

of graphene‟s electrons to imitate massless

particles.

Graphene also portrays extraordinary optical

properties. Graphene only has 2.3% cloudiness

on its honeycomb surface. This leaves an over

98% visual transmission rate, which makes

graphene almost completely transparent

(Figure1) [5]. To make graphene even more

transparent, scientists use a method called

electrical gating, which is made possible by

the limit of electrons in the monolayer and the

low density of states near a Dirac point.

Graphene‟s photoluminescence abilities are

demonstrated first by using chemical or

physical methods to weaken the connection of

the pi-electron network [5].

In future electronics, graphene‟s transparency

and photoluminescence is hoped to be

demonstrated by being placed as the surfaces

of flat-screen computers and televisions.

Figure 1- Graphene‟s incredible transparency

is shown in this figure.

Graphene is the thinnest and strongest material

yet discovered. Its theoretical tensile strength

is 150,000,000 kPa, and its Young‟s modulus

is 1,000,000,000 kPa; therefore, grapheme has

Figure 1- Graphene‟s incredible transparency

is shown in this figure

incredible bending strength and a high

elasticity measurement [5]. Scientists have

proven that

graphene is several times stronger than

diamond and 200 times stronger than steel

[11]. Graphene is so strong that if a coffee

mug was wrapped with a single layer of

graphene, it could withstand the weight of a

car, a weight of approximately 4,000 pounds.

Better yet, a single layer of graphene can

support the weight of an elephant, a weight of

at least 2.6 tons. If one wanted to break

through a single sheet of graphene, an elephant

would need to balance on a pencil to

penetrate graphene‟s surface [12]. Graphene is

also known for its outstanding heat


Poornima R

conductivity. It is the best heat conductor at

room temperature yet discovered. In graphene

and other carbon materials, heat conduction is

controlled by phonons, which are quantized

modes of vibration occurring in a crystal

lattice [8]. Graphene also conducts heat very

well because of its unique electron

arrangement. As a result of each carbon atom‟s

bond with only three other carbon atoms, a 2pz

orbital is left free. As graphene‟s honeycomb

lattice vibrates, the electrons in the 2pz orbitals

jump from atom to atom along the strong

covalent sp2 bonds [10]. These electrons

easily navigate through graphene‟s honeycomb

lattice and carry heat throughout graphene‟s

structure. In other words, the reason why

graphene is an excellent conductor of heat and

electricity is because it has so many mobile

electrons in its structure. After

experimentation on graphene, scientists found

that the room temperature thermal

conductivity of single layer graphene is in the

range of K~ 3000-5300 W/mK depending on

the graphene flake size[5].

Graphene also has magnetic properties as a

result of its unique band structure. Although

pure graphene is not magnetic, scientists can

manipulate it structure that allow graphene to

become magnetic. Scientists remove carbon

atoms from the graphene sheet in order to

promote its magnetism, since magnetism can

be achieved by moving electrically charged

particles [14].

Graphene‟s magnetic field is a result of those

missing carbon atoms which act as tiny

magnets. These tiny magnets strongly

intermingle with graphene‟s electrons. The

electrical current the electrons carry leads to

an extra electrical resistance at low

temperature [14]. After the manipulation of

graphene‟s structure, it becomes an excellent

magnet. When placed in the cold temperatures

of liquid nitrogen, graphene still maintains its

magnetic properties.

IV. SYNTHESIS METHODS Various techniques have been found for

producing thin graphitic films However as

mentioned earlier never were their electronic

properties investigated because of the

difficulty in isolating and transferring them

onto insulating substrates. But in the late 90‟s

Ruoff and co workers tried isolating thin

graphitic flakes on SiO2 substrates by

mechanical rubbing of patterned islands on

HOPG22. However there was no report on

their electrical property characterization.

Using a similar method this was later achieved

in 2005 by Kim and co workers and the

electrical properties were reported. However

the real gold rush in graphene research began

after Geim and co workers first published their

work of isolating graphene onto SiO2 substrate

and measuring its electrical properties. After

discovery of graphene in 2004 various

techniques were developed to produce thin

graphitic films and few layer graphene. They

will be discussed in detail below.

1. Epitaxial growth on metals

2. Mechanical exfoliation

3. Wet Chemical synthesis

4. Epitaxial growth on carbides.

5. Chemical Vapor Deposition

6. Miscellaneous methods.

V. CHEMICAL VAPOUR

DEPOSTION

A scheme of a CVD installation used for

synthesis of

graphene films is shown in Figure 2. Inside the

chamber filled with hydrogen and argon (at

pressures of 500 mbar) a nickel foil (with a

thickness of 25 _m and size of 20×30 mm)

was squeezed between two electrodes. When

an electric current (about 70 A) was applied to

the electrodes, the foil was heated up to a

temperature of about 1000 _C. At this

temperature, the oxide escape from the nickel


Poornima R

foil. After that the foil was cooled down to a

temperature of 800 _C and methane was

injected into the chamber, and then the

temperature was gradually increased to the

desired value. A methane gas decomposed and

the

carbon atoms deposited on the foil surface and

then their diffusion inside the bulk of substrate

started. After that the foil was cooled down to

room temperature with the different cooling

rates, and carbon atoms were pushed to the

surface due to a thermal decompression the

nickel crystalline lattice forming a graphene

film.16 To obtain the required film thickness it

is necessary to control all parameters of the

synthesis process, but the main parameters

deternining the number of formed layers are

the growth temperature, the concentration of

methane and the cooling rate.

Fig. 2. A scheme of installation for CVD synthesis of

grapheme

Fig. 3. Graphene films (a) on a glass substrate, (b) on a

silicon substrate.

Hydrogen. Hydrogen is needed primarily

during annealing to get rid out of the oxide.

Hydrogen is also necessary to reduce the

concentration of methane in the chamber; it is

used simply to dilute the mixture. It did not

significantly affect the results of the

experiment, but completely remove it anyway

is not possible, because the injected methane

then decomposes into carbon and hydrogen.

Fig. 4. The optical images of graphene samples on a

silicon substrate synthesized (a) with argon, (b) without

argon.

Argon. Argon significantly affects the

technical process of synthesis. The argon

thermal conductivity equals to 0.0177 W/(m·

K), which is almost 10 times less than this


Poornima R

value for hydrogen (0.1815 W/(m · K)). This

results in accumulation of the heat near the

substrate and does not allow to loss the energy

of the electrode heating. Due to the nickel foil

is heated by applying of DC, the reduction of

the heat loss makes it possible to heat the foil

of the large size with a low current. In

addition, since the sample itself has a size of

20×30 mm, there is a temperature gradient

from the center to the edges between

electrodes along the nickel foil and it has a

value of 80–100 degrees without the

introduction of argon. But the gradient reduces

to 10–30 degrees if the argon is introduced in

the chamber. Figures 3(a), (b) show the images

of samples on a silicon substrate synthesized

with and without argon. Figures 4(a), (b) show

the Raman spectra for these samples

demonstrating quite a high quality of

graphene.

Fig. 5. The Raman spectra of graphene samples on a

silicon substrate synthesized (a) with argon, (b) without

argon

Methane. Methane is introduced as a source of

carbon atoms. Its concentration is one of the

essential parameters of the process. The more

methane (this means the more carbon atoms) is

introduced into the chamber with the other

fixed parameters, the more number of

graphene layers will be grown. We have

prepared a series of experiments with different

concentrations of methane and on this basis

plotted the dependences of the number of

layers of synthesized graphene on the growth

temperature (Figs. 6(a, b)). An approximate

amount of layers was estimated from the

optical transmission spectra on the basis of the

fact that a single graphene layer absorbs 2.3%

of the incident light. (The inhomogenuity of a

single layer due to the temperature gradient

over the foil should be taken into account.)

Some combination of concentration and

pressure are critical for the process of

synthesis. At concentrations being lower than

2% methane under the pressure of 100 mbar

and less, we have not been able to obtain

graphene. (a)

(b)

VI. FUTURE

APPLICATIONS


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Graphene has a number of properties which

makes it interesting for several different

applications. It is an ultimately thin,

mechanically very strong, transparent and

flexible conductor. Its conductivity can be

modified over a large range either by chemical

doping or by an electric field. The mobility of

graphene is very high which makes the

material very interesting for electronic high

frequency applications. Recently it has become

possible to fabricate large sheets of graphene.

Using near-industrial methods, sheets with a

width of 70 cm have been produced. Since

graphene is a transparent conductor it can be

used in applications such as touch screens,

light panels and solar cells, where it can

replace the rather fragile and expensive

Indium-Tin-Oxide (ITO). Flexible electronics

and gas sensors4 are other potential

applications. The quantum Hall effect in

graphene could also possibly contribute to an

even more accurate resistance standard in

metrology. New types of composite materials

based on graphene with great strength and low

weight could also become interesting for use

in satellites and aircraft.

VII. CHALLENGES

Synthesizing large area high quality single

layer graphene is one of the major challenges.

Recent developments, particularly in CVD

synthesis of graphene on metal substrates have

proved to be major breakthroughs in

overcoming this challenge. Currently,

applications for graphene are limited because

it is too expensive to mass produce [13]. Not

only is it expensive, it is also difficult to

isolate multiple layers of graphene. Graphene

synthesis by exfoliation and other methods

take a while to complete, and they do not

produce a high yield of graphene. Another

disadvantage of using graphene is that until

now, graphene-related materials existed only

as conductors or insulators, never as semi-

conductors that are necessary for electronic

applications [13]. Since graphene is a

relatively new nonmaterial, its safety is

unknown when exposed to different

environments and living systems Because

graphene has an efficient, fast, and mass less

flow of electrons, scientists are having a

difficult time turning off its electrical current,

which delays and prevents graphene research.

CONCLUSION

The development of this new material, opens

new exiting possibilities. It is the first

crystalline 2D-material and it has unique

properties, which makes it interesting both for

fundamental science and for future

applications. The ideal graphene based

technology would be high definition

televisions and computers as thin as wallpaper,

or cell phones that you can wrap around your

wrist and fold into your pocket. Despite being

the smallest material known to

mankind, it is the strongest material in the

world. After evaluating graphene‟s various

properties, it is no wonder that graphene is

called the “wonder material.” With slight

modification to graphene‟s structure, scientists

will be able to make graphene an even better

conductor of heat and electricity, which will

improve and stimulate the manufacturing of

the

electronic devices and technology of the

future.

REFERENCES

[1] H.W. Kroto, J.R. Heath, S.C. Obrien, R.F. Curl, R.E.

Smalley, Nature 318 (1985) 162.

[2] S. Iijima, Nature 354 (1991) 56.


Poornima R

[3] K.S. Novoselov, A.K. Geim, S.V. Morozov, D.

Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A.

Firsov, Science 306 (2004) 666.

4. Gerstner, Ed. “Nobel Prize 2010: Geim and

Novoselov.” Nature Physics October 5, 2010

5. Yao, Jun; Sun, Yu; Yang, Mei; Duan, Yixiang.

“Chemistry, physics, and biology of

graphene-based nanomaterials: new horizons for

sensing, imaging, and medicine” Journal of Materials

Chemistry 14313/22 (2012)

6. Sarkar, Santanu; Bekyarova, Elena; Haddon, Robert

C. “Covalent chemistry in graphene electronics”

Materials Today 6/15 (2012)

7. Zhan, Da; Yan, Jiaxu; Lai, Linfei; Ni, Zhenhua; Liu,

Lei; Shen, Zexiang. “Engineering the Electronic

Structure of Graphene” Materials Views (2012)

8. Shahil, Khan M.F.; Balandin, Alexander A. “Thermal

Properties of graphene and multilayer graphene:

Applications in thermal interface materials” Solid State

Communications (2012)

9. Jiang, Z.; Zhang, Y; Tan, Y.-W.; Stormer, H.L.; Kim,

P. “Quantum Hall effect in graphene” Solid State

Communications (2007)

10. A. Reina, X. Jia, J. Ho, D. Nezich, H. Son, V.

Bulovic, M. S. Dresselhaus, and J. Kong, Nano Lett. 9,

30 (2009).

11. A. L. Vázquez de Parga, F. Calleja, B. Borca, M. C.

G. Passeggi, J. J. Hinarejos, F. Guinea, and R. Miranda,

Phys. Rev. Lett. 100, 056807 (2008).

12. K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim,

K. S. Kim, J.-H. Ahn, P. Kim, J.-Y. Choi, and B. H.

Hong, Nature 457, 706 (2009).

13. “Graphene-Based Electronics: Entirely New

Carbon-Based Material Synthesized from Graphene”

Science Daily April 16, 2012

14. X. Li, W. Cai, J. An, S. Kim, J. Nah, D. Yang, R.

Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K.

Banerjee, L. Colombo, and R. S. Ruoff, Science 117,

1245 (2009).

15. A. Reina, S. Thiele, X. Jia, S. Bhaviripudi, M. S.

Dresselhaus, J. A. Schaefer, and J. Kong, Nano Res. 2,

509 (2009).

16. M. G. Rybin, A. S. Pozharov, and E. D. Obraztsova,

Phys. Status Solidi C 7, 2785 (2010).

[17] M. Luleva. (2013). “Graphene Can Be Harmful to

Human Cells, Scientists Say.” The Green Optimistic.

(Online article).

http://www.greenoptimistic.com/2013/07/15/researchers

discover-properties-of-graphene-harmful-to-

humancells/#. Um3GyPk_vpp

[18] “Graphene „miracle material‟ could be toxic to

humans.” io9. (Online article). http://io9.com/i-can-see-

how-thismight-be-a-problem-i-often-enjoy-ea-

789664034

http://www.greenoptimistic.com/2013/07/15/researchersdiscover-properties-of-graphene-harmful-to-humancells/




Bindiya Patil, Shruthi B.R, Roopashree B.G

ETHICAL ISSUES OF MONITORING ALZHEIMER‘S

PATIENTS


MVJ College OF Engineering, Bangalore, India

[email protected]

Abstract— Alzheimer's disease (AD), also

known in medical literature as Alzheimer

disease, is the most common form of

dementia. There is no cure for the disease,

which worsens as it progresses, and

eventually leads to death. Recently, numerous

systems for geo-tracking Alzheimer’s patients

with dementia are developed and reported to

be functional for the purposes of security and

data collection. However, it was also reported

that use of such systems had generated

ethical issues. Studies stated possible loss of

freedom and autonomy for patients, along

with violations of their privacy, which may

lead to loss of prestige/dignity. In this project

we are developing a geo-tracking system that

aims to balance patients’ security and their

need for privacy and autonomy is proposed. It

simply tries to maintain patients’

independence while assuring they are secure.

INTRODUCTION

In this project we are designing and

developing a system which will continuously

track the position of the patient and send the

location information to home. We are using

RF communication technology to track the

patient location and send this information to

home. To track the location of the patient, we

are placing a RF ID tag in the device that the

patient can wear. The Antennas placing at

different locations will receive the signal from

the RF ID tag of the patient and send the

location information to home.

In this project we are also continuously

monitoring the biomedical parameters like

sweating and body muscle movement of the

patient which will help the care taker to

understand the health condition of the patient

and to take necessary action. We are placing a

sweat detector and an EMG Stimulator on the

device that the patient can wear. The sweat

detector is using to find whether the patient

body is sweating due to high blood pressure

and EMG Stimulator to find if the patient is

having shivering. If this system detects any

change in these parameters, then immediately

it will send the information to home via RF

technology.

This project is also designed to send a

message to care taker or family member via

GSM. This project will help to improve the

freedom, privacy and security of the patient

along with that it will help the care taker to

monitor the patient movement and health

condition without being with them.

I. PROCEDURE

A. Review Stage

EMG Sensor

Electromyography (EMG) is an

electrodiagnostic medicine technique for

evaluating and recording the electrical activity

produced by skeletal muscles. EMG is

performed using an instrument called an

electromyograph, to produce a record called an

electromyogram. An electromyograph detects

the electrical potential generated by muscle



cells when these cells are electrically or

neurologically activated. The signals can be

analyzed to detect medical abnormalities,

activation level, or recruitment order or to

analyze the biomechanics of human or animal

movement.

EMG signals have a variety of clinical

and biomedical applications. EMG is used as a

diagnostics tool for identifying neuromuscular

diseases, or as a research tool for studying

kinesiology, and disorders of motor control.

EMG signals are sometimes used to guide

botulinum toxin or phenol injections into

muscles. EMG signals are also used as a

control signal for prosthetic devices such as

prosthetic hands, arms, and lower limbs.

Electrical activity is recorded extracellularly

from muscle fibres that are embedded in the

tissue. This is used the detect the body muscle

movements. EMG sensor is preferred over

vibration sensor since the latter detects even

the smallest muscle movements whereas in the

former cut off frequency can be set.

Sweat Detector

Galvanic skin resistance (GSR) - This is also

called electro-dermal activity, and is basically

a measure of the sweat on your fingertips. The

finger tips are one of the most porous areas on

the body and so are a good place to look for

sweat. The idea is that we sweat more when

we are placed under stress. Fingerplates, called

galvanometers, are attached to two of the

subject's fingers. These plates measure the

skin's ability to conduct electricity. When the

skin is hydrated (as with sweat), it conducts

electricity much more easily than when it is

dry.

In this project, we use sweat detector which

consists of two electrodes which conduct in the

presence of salt content in sweat. The distance

between the two electrodes is directly

proportional to the sensitivity of sweat

detector.

.

B. Final Stage

MONOSTABLE MULTIVIBRATOR

The timer comprises two operational

amplifiers (used as comparators) together with

an RS Bistable element. In addition, an

inverting output buffer is incorporated so that a

considerable current can be sourced or sunk

to/from a load. A single transistor switch,

TR1, is also provided as a means of rapidly

discharging the external timing capacitor.

The standard 555 timer is housed in an 8-pin

DIL package and operates from supply rail

voltages of between 4.5V and 15V. This

encompasses the normal range for TTL

devices and thus the device is ideally suited for

use in conjunction with TTL circuitry.

MICROCONTROLLER

The general definition of a microcontroller is a

single chip computer, which refers to the fact

that they contain all of the functional sections

(CPU, RAM, ROM, I/O, ports and timers) of a

traditionally defined computer on a single

integrated circuit. Some experts even describe

them as special purpose computers with

several qualifying distinctions that separate

them from other computers.

Microcontrollers are "embedded" inside some

other device (often a consumer product) so that

they can control the features or actions of the

product. Another name for a microcontroller,

therefore, is "embedded controller."

Microcontrollers are dedicated to one task and

run one specific program. The program is

stored in ROM (read-only memory) and

generally does not change.

HEX BUFFER / CONVERTER [NON-

INVERTER] IC 4050: Buffers does not affect

the logical state of a digital signal (i.e. logic 1

input results into logic 1 output where as logic

0 input results into logic 0 output). Buffers are

normally used to provide extra voltage drive at

the output, but can also be used to regularize

the logic present at an interface. And Inverters

are used to complement the logical state (i.e.

logic 1 input results into logic 0 output and

http://people.howstuffworks.com/sweat.htm



vice versa). Also Inverters are used to provide

extra voltage drive and, like buffers, are used

in interfacing applications. This 16-pin DIL

packaged IC 4050 acts as Buffer as-well-as a

Converter. The input signals may be of 2.5 to

5V digital TTL compatible or DC analogue the

IC gives 5V constant signal output. The IC acts

as buffer and provides isolation to the main

circuit from varying input signals. The

working voltage of IC is 4 to 16 Volts and

propagation delay is 30 nanoseconds. It

consumes 0.01 mill Watt power with noise

immunity of 3.7 V and toggle speed of 3

Megahertz.

RADIO FREQUENCY ID

Radio must surely be one of the most

fascinating aspects of electronics. This part of

explanation provides a brief introduction to

radio communication before describing the

circuitry of RF receivers and transmitters. The

aim has been to provide the user with

sufficient information to what his or her

appetite for a subject which has a broad appeal

to a large number of dedicated enthusiasts all

over the world.

Radio frequency signals are generally

understood to occupy a frequency range, which

extends from a few tens of kilohertz to several

hundred giga-hertz. The lowest part of radio

frequency range, which is of practical use

(below 30 kHz), is only suitable for narrow-

band communications. At this frequency,

signals propagate as ground waves (following

the curvature of the earth) over very long

distance. At the other extreme, the highest

frequency range, which is of practical

importance, extends above 30GHz. At these

‗microwave‘ frequencies, considerable

bandwidths are available (sufficient to transmit

many television channel using point-to-point

links or to permit very high definition radar

systems) and signals tend to propagate strictly

along ‗line-of-sight‘ paths.

C.Figures

II. CONCLUSION

The project report has shown various ethical

issues faced by a person with Alzheimer‘s

disease and the remedy for these issues. This

project aims at providing a person his/her

privacy or independent life style without

depending on other person for help.

In this project the device designed is capable

of tracking both the blood pressure and

epilepsy. When there are any changes in the

parameters such as temperature, blood

pressure, occurring of epilepsy etc, the device

will detect these signals using various sensors

built in the device and inform the care taker

about the changes in patient‘s medical status

and location of the patient. Because of which

the patient is free to go wherever he wants

within limited range of some meters.



Here, we fix various sensors on the body of the

patient (arm) which will detect various

changes in the patient‘s medical status. These

signals are then amplified to confirm the

existence of problem or emergency in patient‘s

status and then the signals are sent to the care

taker.

In this project we use RF and GSM

technologies to provide the communication

channel or path. It is advantages to use both of

them as the message can be sent to the care

taker by either of the way and in some cases if

one connections break or doesn‘t support we

can send the message by the other

communication device.

Hence, in this project we can solve some of the

ethical issues faced by the patient with

Alzheimer‘s disease.

REFERENCES

[1] G. O. Young, ―Synthetic structure of industrial

plastics (Book style with paper title and editor),‖

in Plastics, 2nd ed. vol. 3, J. Peters, Ed. New

York: McGraw-Hill, 1964, pp. 15–64.

[2] W.-K. Chen, Linear Networks and Systems (Book

style). Belmont, CA: Wadsworth, 1993, pp. 123–

135.

[3] H. Poor, An Introduction to Signal Detection and

Estimation. New York: Springer-Verlag, 1985, ch.

4.

[4] B. Smith, ―An approach to graphs of linear forms

(Unpublished work style),‖ unpublished.

[5] E. H. Miller, ―A note on reflector arrays (Periodical

style—Accepted for publication),‖ IEEE Trans.

Antennas Propagat., to be published.

[6] J. Wang, ―Fundamentals of erbium-doped fiber

amplifiers arrays (Periodical style—Submitted for

publication),‖ IEEE J. Quantum Electron.,

submitted for publication.

[7] C. J. Kaufman, Rocky Mountain Research Lab.,

Boulder, CO, private communication, May 1995.


Divyashree M, Shivakanth

STUDY OF DIODE, BIPOLAR JUNCTION

TRANSISTOR AND OP-AMP USING MATLAB


Telecommunication Engineering Department,

MVJ College of Engineering, Bangalore, India

E-mail id1: [email protected]

E-mail id2:[email protected]

Abstract— MATLAB (Matrix Laboratory)

is a numeric computation software for

engineering and scientific calculations.

It is being used to teach circuit theory, filter

design, random processes, control system

and communication theory. Matrix

functions are shown to be versatile in doing

analysis of data obtained from electronics

experiments. In this paper the graphical

features of MATLAB are especially useful

for display of characteristics of a diode,

temperature effects on diode, input and

output characteristics of transistor for CB

configuration and the input and output

voltages of the inverting op-amp.

Keywords— MATLAB, CB configuration,

diode, transistor, op-amp.

I. INTRODUCTION

MATLAB is a high level language whose

basic data type is a matrix that does not

require dimensioning. There is no

compilation and linking of programs as it is

normally done in other high level languages,

such as C or FORTRAN. In MATLAB, all

computations are done in complex valued

double precision arithmetic to guarantee high

accuracy. MATLAB has a rich set of plotting

capabilities. The graphics are integrated into

MATLAB. Since MATLAB is also a

programming environment, a user can extend

the functional capabilities of MATLAB by

writing new modules. MATLAB has a large

collection of toolboxes for variety of

applications. A toolbox consists of functions

that can be used to perform some

computations in the toolbox domain.

In this paper, the following topics of

electronics will be discussed: diodes, bipolar

junction transistors, operational amplifier and

its characteristics are studied using

MATLAB.

II. DIODES

In this chapter the characteristics of diodes

and temperature effects on the diodes will be

discussed using MATLAB.

A. Diode Characteristics

Diode is a two-terminal device. The

electronic symbol of a diode is shown in Fig.

1. Ideally, the diode conducts current in one

direction. The current versus voltage

characteristics of an ideal diode are shown in

Fig. 2.

Fig. 1 Electronic symbol of diode.

Fig. 2 Ideal diode I-V characteristic

The I-V characteristic of a semiconductor

junction diode is shown in Fig. 3. The

characteristic is divided into three regions:




forward-biased, reversed biased and the

breakdown.

Fig. 3 I-V characteristic of a semiconductor

junction diode.

In the forward-biased and reversed-biased

regions, the current i and the voltage v, of a

semiconductor diode are related by the diode

equation

Where IS is reverse saturation current or

leakage current, n is an empirical constant

between 1 and 2,

VT is thermal voltage, given by

k is Boltzmann’s constant = 1.38e−23 J /oK

q is the electronic charge = 1.6e−19

Coulombs

T is the absolute temperature in oK

At room temperature (25 oC), the thermal

voltage is about 25.7 mV.

-0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.05-1

0

1

2

3

4

5

6

7x 10

-6 Characteristic of semiconductor diode

Voltage v, V

Curr

ent

i, m

A

Fig. 4 I-V characteristic of a forward

biassemiconductor junction diode.

The I-V characteristic of a forward biased

semiconductor junction diode using

MATLAB is shown in Fig. 4.

B. Temperature effects on diode

From the diode equation (1), the thermal

voltage and the reverse saturation current are

temperature dependent. The thermal voltage

is directly proportional to temperature. This

is expressed in equation (2). The reverse

saturation current IS increases approximately

7.2% /oC for both silicon and germanium

diodes. The expression for the reverse

saturation current as a function of

temperature is

(3)

Where kS = 0.072 / o C. T1 and T2 are two

different temperatures. Since e0.72

is

approximately equal to 2, equation (3) can be

simplified and rewritten as

The variation in temperature causes the

change in behavior of the diodes. For

forward biased junction, as temperature is

increased, the forward current increases for a



given forward voltage. Temperature can have

remarkable effect on the V-I characteristics

of a diode. The saturation current of a diode

at 25 oC is 10

-12 A. Assuming that the

emission constant of the diode is 1.9, Fig 5

shows plotting of the I-V characteristic of the

diode at the following temperatures: T1 = 0 oC, T2 = 100

oC using MATLAB.

0.45 0.5 0.55 0.6 0.65 0.7 0.750

1

2

3

4

5

6

7

8

9

10Diode I-V Curve at two Temperatures

Voltage (V)

Curr

ent

(A)

o is for 100 degrees C

+ is for 0 degree C

Fig. 5 Temperature Effects on the Diode Forward

Characteristics.

III. BIPOLAR JUNCTION

TRANSISTORS

Transistor is a three terminal device: Base,

emitter and collector, can be operated in

three configurations common base, common

emitter and common collector. Bipolar

junction transistor (BJT) consists of two p-n

junctions connected back to back. The

operation of the BJT depends on the flow of

both majority and minority carriers. There

are two types of BJT: NPN and PNP

transistors. The electronic symbols of the two

types of transistors are shown in Fig. 6.

(a)

(b)

Fig. 6 (a) NPN Transistor (b) PNP Transistor

A. Common base configuration

Fig. 7 shows NPN transistor in common base

configuration. In this circuit arrangement,

input is applied between emitter and base

terminals and output is taken from collector

and base terminals. In this circuit, base

terminal is common to both input and output

hence the common base (CB) configuration.

Fig. 7 Common base configuration of NPN

Transistor

1. Input Characteristics

Input characteristics are obtained between

input current and input voltage with constant

output voltage. First keep the output voltage

VCB constant and vary the input voltage

VEB for different points then at each point

record the input current IE value. Repeat the

same process at different output voltage

levels. Now with these values we need to plot

the graph between IE and VEB parameters.

The below figure show the input

characteristics of common base

configuration. The equation to calculate the

input resistance Rin value is given below.

2. Output Characteristics

The output characteristics of common base

configuration are obtained between output

current and output voltage with constant

input current. First keep the emitter current

constant and vary the VCB value for different

points, now record the IC values at each point.



Repeat the same process at different IE values.

Finally we need to draw the plot between

VCB and IC at constant IE. The below figure

show the output characteristics of common

base configuration. The equation to calculate

the output resistance value is given below.

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.650

5

10

15

20

25

30

35Input characteristics

Base-emitter voltage, V

Em

itte

r curr

ent,

A

Fig. 8 Input Characteristics of CB configuration

0 1 2 3 4 5 60

1

2

3

4x 10

-4 Output Characteristic

Collector-base Voltage, V

Collecto

r curr

ent,

A

Fig. 9 Output Characteristics of CB configuration

Thus in this chapter input and output

characteristics of CB configuration of NPN

transistor are studied using MATLAB as

shown in Fig 8 and Fig 9 respectively.

IV. OPERATIONAL AMPLIFIERS

The op amp is one of the basic building

blocks of linear design. The name “op amp”

is the standard abbreviation for operational

amplifier. In its classic form it consists of

two input terminals, one of which inverts the

phase of the signal, the other preserves the

phase, and an output terminal. The standard

symbol for the op amp is given in Fig 10.

Fig. 10 Op-amp Symbol

There are two configurations. An op amp

connected in a non-inverting configuration is

shown in Fig 11. An op amp circuit

connected in an inverted closed loop

configuration is shown in Fig. 12.

Fig. 11 Non-inverting configuration

Fig. 12 Inverting configuration

Model the operational amplifier as an ideal

op amp. Then the output voltage of the

inverting amplifier is

related to the input voltage by



When voltage saturation is included in the

model of the operational amplifier, the

inverting amplifier is described by

(8)

Where Vsat denotes the saturation voltage of

the operational amplifier. Equation 8 is a

more accurate, but more complicated, model

of the inverting amplifier than Equation 7. Of

course, we prefer the simpler model, and we

use the more complicated model only when

we have reason to believe that answers based

on the simpler model are not accurate.

Fig. 13 illustrate the use of MATLAB to

analyze the inverting amplifier when the

operational amplifier model includes voltage

saturation and it shows the MATLAB input

file, corresponding to the circuit shown in

Fig.12.

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-3

-20

-15

-10

-5

0

5

10

15

20

time, s

vo(t

), V

Fig. 13 The input and output voltages of the inverting

amplifier.

V. CONCLUSIONS AND FUTURE

ENHANCEMENT

Areas in electronics where MATLAB can be

used to teach electronics principles and

concepts to engineering students are

discussed. In this paper MATLAB has been

used to examine the characteristics of diode,

transistor and op-amp. The versatile nature of

MATLAB allows "what-if'' analysis that can

be used to strengthen students understanding

of electronics. MATLAB is useful in

analysing data obtained from electronics

laboratory experiments.

Future work can be done for the AC circuit

analysis, DC circuit analysis and transient

analysis of a electrical network can be

studied using MATLAB.

REFERENCES

[1] “Electronic Devices and Circuit Theory”, Robert

L. Boylestad and Louis Nashelsky, PHI/Pearson

Education, 9th

Edition.

[2] “Electronic Devices and Circuits”, David A. Bell,

PHI, 4th

Edition, 2004.

[3] David, McMahon, “MATLAB Demystified”,

McGraw Hill.

[4] J. A. Gow, C. D. Manning “Development of a

photovoltaic array model for use in power

electronics simulation studies,” IEEE

Proceedings on Electric Power Applications, vol.

146, no. 2, pp. 193-200, March 1999.

[5] D. Nelson , S. Evans . A new approach to op

amp design, Databook.

[6] A. Sedra , K.C. Smith . A second generation

current conveyor and its applications. IEEE

Trans. Circuit Theory , 132 - 134

[7] H. K. Gummel "A self-consistent iterative

scheme for one dimensional steady state

transistor calculations", IEEE Trans. Electron

Devices, vol. ED-11, pp.455 -465 1964

[8] Ruben Rojas-Oviedo, Dr. X. Cathy Qian,

“Improving Retention of Undergraduate Students

in Engineering through Freshman Courses”,

Proceedings of the ASEE Annual, Montréal,

Quebec, Canada 2002.

[9] Andrew Kline, Betsy M. Aller, and Dr. Edmund

Tsang, “Improving student retention in STEM

disciplines a Model that has worked”,

Proceedings of the ASEE Annual Conference,

2011.

Editorial Board

Chief Editor

Ms. Banashankari – Chief Librarian


Editors

Prof. Thyagarajan – Director R&D

Dr. Kumar – Professor, Dept. of Civil Prof. S C Gupta – HOD, Dept. of AE

Dr. B Ramdas Balan– HOD, Dept. of Physics

Technical Editor

Ms. Shilpa S – Asst. Professor, Dept. of ISE




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