The Newspaper of The Institution of Engineers, Sri Lanka Vol. 47, No 02, February 2012

Registered at the GPO as a Newspaper No. QD/86 /NEWS/2011

ENGINEERING NEWSSRI LANKA

Established 1906

Late Eng. (Prof.) R.H.PaulCommemoration at IESL

The 108th birth anniversary of Late Eng.(Prof.) Robert Hoisington Paul wascommemorated with a Memorial Lecture held at the WimalasurendraAuditorium of the Institution of Engineers, Sri Lanka(IESL) at 120/15, Wijerama Mawatha,

Colombo 7, on Friday 10th February 2012 . Considered as the “Father of electrical engineeringeducation in Sri Lanka” for his contributions to our engineering education in the electricalengineering discipline at the university level in its formative stages, the late Professor is a

IESL Engineering CourseCeremonially Inaugurated

President – IESL, Eng. (Dr.) Ananda Ranasingheaddressing the audience at the inauguration ceremony.Also in the picture are (L to R) Eng. WimalasenaGamage - Chairman(Education, Examination & TrainingCommittee) Prof. Ananda Jayawardane – ViceChancellor, University of Moratuwa,Eng. Tilak De Silva- President Elect, Eng. Ms. Arundathi Wimalasuriya,Executive Secretary

The Stage 1 of the Engineering Course conducted by the Institution of Engineers, Sri Lanka (IESL) was inaugurated at a ceremony attended by a large numberof fresher students, parents, lecturers, Council Members andstaff of the IESL on 28th January at the Head Office of theinstitution at 120/15, Wijerama Mawatha, Colombo 07.

The course has become a lifeline to many students aspiringto be qualified engineers but unable to gain entrance to theuniversities due to the higher education bottleneck in thecountry.

symbol of the veryprofessionalism he tried toinculcate in his students. TheR.H.Paul Memorial Lecture thisyear was delivered by Eng.Mangala P.B.Yapa – ManagingDirector/CEO of ColomboDockyard PLC, on the theme“Engineering Education andPractices : Issues and FutureChallenges”. At a time whenvalues held sacrosanct by theprofession are being erodedapparently, commemorationsof great men of the past whohad upheld such values couldprovide the appropriateopportunities for areawakening process that isclearly and urgently needed.

Delivering the lecture Eng.Mangala Yapa described thelate Prof.. R.H.Paul as a man ofgreat vision, dedication andcommitment to his professionwho created the pathway formany Sri Lankans to learnengineering in Sri Lanka Hesaid that an important part oflate Professor Paul’s role as aneducationalist and an engineerwas the support he extendedtowards the establishment ofan industry in the country, whereelectrical engineers couldpractice, at that time under theDepartment of GovernmentElectrical Undertakings(DGEU). He further said that thelate Professor always identifiedthat the role of engineers is toserve their community with asense of purpose, and tochallenge what needs to bedone and use the learning asan opportunity to serve thesociety at large. SubsequentlyEng. Mangala Yapa highlightedthe apparent erosion of valuesthe profession has suffered inpresent times and theimportance of the need to findout the reasons for it. He saidthat the reason perhaps lies inthe fact that we have failed toevolve with the changesbrought with the times.

The memorial lecture waspreceded by the lighting of thetraditional oil lamp, garlandingof the photograph of the lateEng. (Prof)R.H.Paul and thewelcome address by thePresident of the IESL

Contd. on page 11....

PLEASE SHARE YOUR VALUABLE EXPERIENCES – PRESIDENT

The President visitedTrincomalee recentlyand had met Eng. K.

Sivakumar, the Team Leaderof the Gantalawa toTrincomalee RoadRehabilitation Project whichis identified as A6.

During the discussions thatfollowed Eng. Sivakumar hadmentioned about a veryinteresting project that hadbeen carried out in order torehabilitate the Trincomalee-Pulmoddai Road identified asB424.

The Contractor for this projectwas China Auto and theConsultants were RDC &Pacific ConstructionInternational. The length ofthis road was approximately

55 km and the road formationconsisted of 15m of road-width.

According to Eng.Sivakumar, he hadencountered a scarcity ofmaterials in order to lay thebase course of the road.Therefore, a decision hadbeen made to utilize theexisting material and graveland to modify this material inorder to bear the excessivetraffic load which isanticipated afterconstruction.

Due to the availability of gravelin this area, the additionalbase requirements wereaugmented by using theexisting gravel in the area.This gravel was stabilized

using cement and thepercentage of cement thathad been used for thispurpose was less than 3% involume. As the mixing ofgravel and cement could notbe carried out in situ, aspecial machine wasimported from China which heidentified as a ‘Pugmill’. Thisequipment is nothing but amixer having a capacity of200 Metric Tonnes per hour,to mix large volumes ofgravel. As cement was usedin bulk, it was stored in silos.Due to the chemical reactionwhich takes place in cement,mixing time had to be limitedto 1-1/2 hours and thestabilized soil mixture laid onthe ground immediately afterthat. After laying the basematerial, compaction was

done using the road rollers.According to Eng.Silvakumar, in order to formthe road the sub-

In this Issue

The Institution of EngineersSri Lanka

120/15, Wijerama Mawatha,Colombo 7, Sri Lanka.

Tel: 2685490, 2698426, 2699210

Fax: 2699202

E.mail: ed@sltnet.lk / iesl@slt.lk

Website: http://www.iesl.lk

Highway

Driving................................. 2

Editorial ............................... 4

Puzzle of the...................... 5

month

Eng. Mangala P B Yapa delivering theMemorial Lecture

A section of audience at thememorial lecture

ArbitrArbitrArbitrArbitrArbitratatatatatororororors ands ands ands ands andAAAAAdjudicatdjudicatdjudicatdjudicatdjudicatororororors Ts Ts Ts Ts Trrrrrainingainingainingainingaining

PrPrPrPrProgogogogogrrrrrammeammeammeammeammeThe IESL will conduct the above Training Programme

commencing Saturday, 31st March 2012, 9.00 a.m. and

continuing on the following 3 Saturdays.

Those interested in following the programme are

kindly requested to contact the Deputy Executive

Secretary.

Sri Lanka Engineering News - February 2012IESL NEWS2

FORTHCOMING ANNUALEVENTS CALENDAR -

2011 / 2012Event Dates

♦♦♦♦♦Induction and Graduation Ceremony Friday – August 17, 2012

♦♦♦♦♦E O E Pereira Memorial Lecture Thursday – September 13, 2012

♦♦♦♦♦D J Wimalasurendra Monday – September 17, 2012 Memorial Lecture♦♦♦♦♦Techno Exhibition Friday – Sunday October 5-7, 2012♦♦♦♦♦Inauguration of the Annual Sessions Friday – October 19, 2012

♦♦♦♦♦Annual Sessions Seminar Saturday – October 20, 2012

♦♦♦♦♦Annual Field Visit Sunday – October 21, 2012

♦♦♦♦♦Presentation of Technical papers Monday-WednesdayOctober 22, 23 & 24, 2012

♦♦♦♦♦Presentation of Technical Papers Thursday - October 25, 2012 by Young Members

♦♦♦♦♦Dr. A N S Kulasinghe Thursday – October 25, 2012 Memorial Lecture♦♦♦♦♦Techno Awards Ceremony Wednesday – October 24, 2012♦♦♦♦♦Annual General Meeting Saturday – October 27, 2012

The date of the Dr. Ray Wijewardene Memorial Lecture will be notified later.

Note:

Associate Members who wish to apply for the Professional Review,are strongly advised to attend all Memorial Lectures and keep a recordof the attendance for any future reference.

ANNUAL SUBSCRIPTIONFEES FOR THE YEAR 2012

Class of Amount in Rs.Membership (Excluding VAT)

Fellow 5000Member 4000Associate Member 3000Affiliate Member 2500Associate 2500Companion 2500Student Member < 35 1000Student Member > 35 2500

International Professional Engineer (IntPEng)Subscription Fees excluding VAT- Rs 2,500/=

DiscountsIn respect of membership subscription fees, a discount of 25%

will apply to members other than Student Members who are

above 60 years of age and who declare that their annual

income is less than Rs. 600,000/=.

THE INSTITUTION OF ENGINEERS,SRI LANKA

“PROJECT MANAGEMENTPROFESSIONAL

TRAINING PROGRAMME”Programme covers the various project Management areas ; such asProject Management Process, Integration Management, ScopeManagement, Time Management, Cost Management, QualityManagement, Human Resource Management, CommunicationsManagement, Risk Management, Procurement Management

For whom: Professionals interested in pursuing theProject Management in their professionalroles.

Resource Persons:••••• Mr. N R Asoka de Silva,

BSc.Eng.,MIE(Ireland),MIE(USA)Senior Management Consultant, NIBM

••••• Mr. L.N Theverapperuma,BA(Cey),MBA(Sri J).,Former Senior Management Consultant, NIBM

••••• Mr. Y. Ratnayake, BA (Peradeniya)),MBA(Sri J).,Former Senior Management Consultant, SLIDA

Duration: Commencing on, March 10th 2012, will beconducted06 Saturdays from 0900 - 1600 hrs. at IESL.

Course Fee: Rs.27,000/- for members of IESL andRs.29,000/- for others (inclusive ofHandouts, Lunch & Refreshments)

For further details contact Education, Examinations &Training Division

Tel. : 011 2 698 426 Ext. 209/210/211Fax : 011 2 699 202 E-mail : deetiesl@sltnet.lk

DIRECTOR (EE&T) 120/15, Wijerama Mawatha, Colombo 7.

__________________________________________________THE INSTITUTION OF ENGINEERS, SRI LANKA

“Project Management ProfessionalTraining Programme”

March 10, 2012Six Saturdays from 0900-1600 hrs

REGISTRATION FORMDirector, Education Examinations & TrainingThe Institution of Engineers, Sri Lanka120/15, Wijerama MawathaColombo 07.

(Tel. 2 698426 Ext. 209/210 Fax:2 699202 E-mail : deetiesl@sltnet.lk)

1. Name Mr./Ms.

2. IESL Membership No. (If any)

3. Designation

4. Organisation with

address

5. Residence Address

Office :

6. Contact Nos. Residence : E-mail :

Mobile : Fax:

7. Food preference Non-vegetarian Vegetarian

Name of the Nominating Officer/Applicant * …………..................……

Designation........................................................................................

Signature ………………....................................................................…

Date…………………………………………….......................………………

Await in March 2012Half a Day Seminar on ‘Current Status and

Future of Oil Industry in Sri Lanka’ organized by the Chemical and Process Engineering Sectional

Committee of IESL.

Sri Lanka Engineering News - February 2012IESL NEWS 3

HIGHWAY DRIVING – 2THE CORNERING MANEUVER – SLOW IN - FAST OUT

by Eng Sarath Chandrasiri

Now we have a forwardaccelerating force F at thecenter of mass and a coupleFXd acting on the wholevehicle. The first propels thecar forward while the secondtends to rotate it in aclockwise direction in theplane of the paper. Whatinterests us here is thiscouple, as a result of whichthe front tyres of the car getpushed up and the rear tyresget pushed down. Theopposite happens when youbrake. What this means isthat acceleration and brakingaffects the weight distributionon the 4 tyres of the vehicle.

Tyre Grip: How the weightof the vehicle is distributedamong the 4 wheels is veryimportant for the stability orroad holding of the vehicle.This is because the weighton a tyre decides how muchgrip there is on it. By grip wemean the forces exerted atthe patch of contact of thetyre with road surface (Fig-2). The grip can extend in twodirections, (i) TheLongitudinal Grip (F1) inthe plane of rotation of thetyre and (ii) The Lateral Grip(F2) in a directionperpendicular to the sameplane. The sign of F1 depends

Whether it is normaldriving or highwaydriving, cornering

may be considered as amaneuver, with which a highdegree of risk is associated.The motto to be followed incornering may besummarized as: SLOW IN- FAST OUT. Perhaps incompetitive racing, this rulehas to be violated to someextent. But in day to daydriving it is a golden rule thatcan keep you out of trouble.

In the SLOW IN - FAST OUTtechnique, as you approacha corner (a bend on the road),you have to slow downgradually by smoothlypressing the brake pedal.Once you enter the corneryou must keep your foot offthe brake pedal and come outof the corner with your footon the accelerator, achievinga higher speed than thespeed of entry.

In general highways areconstructed without sharpcurves and any curves, thatare there, are banked to suita certain speed. However,even if that may be the case,the high speeds at whichvehicles are driven onhighways makes the SLOWIN - FAST OUT approach auseful motto even on them.On the other hand, on otherroads of Sri Lanka, it is animperative. Therefore, it isnecessary to understand the

dynamics involved incornering, to fully appreciatethe usefulness of the SLOWIN - FAST OUTmethodology.

Frame of Reference: Firstof all, in order to start out ina mathematically rigorousmanner, we have to define theframe of reference we areusing, which in this casehappens to be our good oldfriend - THE STATIONARY,FLAT EARTH FRAME ofREFERENCE. It alsomakes literal sense, becausehopefully, it will help theinexperienced anduninformed drivers to remainfirmly attached to the good

old FLAT EARTH whilenegotiating a bend, withoutflying off in to a precipice andrealizing that it is not as flatas our frame of referencesuggests.

Forces Acting on a Vehiclein Motion: Basically, thereare 3 kinds of significantexternal forces acting on avehicle in motion: (i) Theweight acting at the centerof gravity, (ii) the grip exertedon the tyres due to theinteraction between the tyresand the road surface and (iii)the aerodynamic forcesacting on the outer surfaceof the vehicle.

Straight and LevelDriving: Let us first dealwith straight driving, to get abasic idea of the dynamicsinvolved. Let us also ignorethe aerodynamic forces forthe moment as they aresignificant only at highspeeds. When you pressthe accelerator of a car thetyres react with the roadsurface to produce a tractiveforce (F) in the forwarddirection on the car. In orderto understand the effect ofthis force, which is acting atthe bottom of the tyre, wehave to shift it to the centerof mass of the vehicle. Thiscan be done by assumingtwo forces equal andopposite acting at the centerof mass, as shown below,considering just one of therear wheels of a rear wheeldrive vehicle as given in Fig-1:

on whether you areaccelerating or braking.When you travel at a fixedspeed, the accelerator has tobe pressed to providesufficient drive force toovercome F1.

Grip Variations: Forpurposes of vehicle stability,it is beneficial to have a highlevel of grip of the tyres. Thereare many factors, whichdecide the level of grip of atyre, which we leave for a laterdiscussion. But in general,we can say that the grip at agiven tyre increases with theweight borne by it. In thecase of straight motion, thelateral grip is small and is notof much importance, whilethe longitudinal grips are ofmajor importance.

The other importantphenomenon that we have tounderstand is that themaximum value of the lateralgrip available depends on howmuch of the availablelongitudinal grip you areusing at a given moment andvice versa. In other words, thetwo types of grips areinterdependent. If you use upall the available LongitudinalGrip, then the available lateralgrip is reduced to a minimum.This means that there is atrade off here between lateraland longitudinal grips andwhen you need one you haveto minimize the use of theother.

GRIP can be compared to apie (see the figure), fromwhich we can cut off twotypes of pieces, alongitudinal piece and alateral piece. We all like tohave a bigger Pie and theoverall size of the Grip Piecan be increased byincreasing the weightdistributed on the tyre. But ifyou cut off too large a pieceof longitudinal grip then you

are left only with acorrespondingly small pieceof lateral grip.

Understanding this isessential for mastering safecornering.

Cornering: The first part ofthe rule, SLOW IN, meansthat you have to reduce thespeed to a safe value beforeentering the corner. Thisensures that you do not haveto do any braking afterentering the corner becauseall the braking that is neededfor executing the maneuverhas been completed prior tothat. In fact in certainsituations, it isadvantageous to slightlypress the accelerator, whileyou are negotiating thecorner and in that case theextent of braking has to beincreased so as to leave asufficient margin for that.

Cornering involves circularmotion and as engineers weknow that circular motioninvolves our well knownfriends, centrifugal andcentripetal forces. Thisknowledge gives us a majoradvantage over the otherdrivers and could make usmuch better and saferdrivers.

The centripetal force requiredfor cornering is provided bythe lateral grip at the fourtyres. Thus the corneringprocess places a highdemand on the lateral gripsavailable at the tyres. Thelateral grip available at thetyres can be maximized byadopting the followingmeasures:

Reduce the demand on thelongitudinal grip, (i.e.) reducethe size of the longitudinalpiece of the pie. We knowthat braking places anincreased demand on the

Contd. on page 11....

Sri Lanka Engineering News - February 2012IESL NEWS4

Sri LankaEngineering News

Lakshitha Weerasinghe, Editorlakshitha@ieee.org

Letters to the Editor

SLEN Oct. – Nov. Editorial –The other side(s)of the coin

Second comment by Eng. M. K. Chandrasekera

I thank you for being generous to publish my comments on the above Editorial since mypast experience is that the comments I sent on several previous articles that appeared in theSLEN were never published even in summarized form.

It is my considered opinion that an Editor of a paper should not take sides. Opinions expressedby him/her should be based on facts but not on speculative matter.

For example, look at the Editorials written by the Editor of the ISLAND paper. He writesabout diverse subjects daily but always takes care to derive his opinions based on factsobtained from authoritative sources.

I have come across another way of news writing called ‘journalistic jargon’ which is adoptedby newsmen to evoke suspense and get the attention of the readers to their pieces. Thepieces written using that style of writing are not backed by solid facts but on speculativematter.

By reading the questionable paragraph you included (on the subject of Irrigation), the averagereader will tend to think that ‘somebody (with authority) is making a big blunder’ byconstructing the NCP canal instead of extracting the ground water and using it to drip feedthe crops. In the end the readers are left more confused and confounded.

I am sure that you are not in possession of authoritative facts to substantiate your argumentif confronted by person/s who have scientific knowledge on this subject.

While the use of journalistic jargon by the common journalists may be accepted to someextent, I believe that the Editors should refrain from doing so.

If you need a scientific explanation with a view of refreshing your mind on the matters writtenin your questionable paragraph, I can arrange a discussion with a few resource persons.

P.S: Please note that I will not make any more comments on this matter.

Editors comment:

The Editorial under reference was not based on speculation. It cited the NCP Canalmerely as an example to convey the broader message I was conveying from theeditorial that there could be less discernible sides to an issue ( like the 3rd side of aCoin, the edge) . Nowhere has it been implied in the Editorial that the NCP canalwas a blunder.

I leave it to the general readership at this stage to make their own judgments on thesentiments expressed by Eng. Chandrasekera on the style of my Editorials.

As this subject is sufficiently dealt with in this and the previous issue all commentspertaining to the topic will be concluded with this issue.

Editor

LOCAL OR SRI LANKAN?by Eng V.M.Karunaratne.

HLM - 0285

Let me wish the membership (regardless of their class) and the staff of the IESL, thecontributors and the readers of the ‘Sri Lanka Engineering News’ a bright, successfuland a fruitful New Year – 2012.

What prompted me to make (in good faith) the under mentioned comments are,

a) the news item that appeared in the SLEN Vol. 45, No. 08,August / September2010,titled “Local Engineers Successful in Repairing Class M9 Locomotives”

b) The news item that appeared in the SLEN Vol. 46, No. 09,September 2011,titled“Mystery of the Samanala Wewa Leakage solved! Local Engineers and Scientists establishthe Samanala Wewa Leakage mechanism using isotope technology.”

I wish to congratulate the respective authors of the above mentioned news items for highlightingthe achievements of Sri Lankans. However, it is saddening to note the usage of the expression‘Local’ to describe the Sri Lankan professionals who were successful in their endeavors.

Why consider ourselves as ‘Locals’, are we inferior to other nationals? We were born SriLankans. Hence why not uplift ourselves to the level of ‘Nationals’ and call ourselves as SriLankan Engineers, Scientists, Medical Doctors, etc. and in general ‘Sri Lankans’. Therefore,I respectfully request the authors of the above mentioned news items and those who intendwriting articles etc. to the SLEN or to any other publications, to refrain from using the expression‘Local’ to describe Sri Lankan professionals, whether they be Scientists, Engineers, MedicalDoctors, etc.

In view of the aforementioned, the Editor of the SLEN is kindly requested to substitute theexpression ‘Sri Lankan’ in place of ‘Local’ whenever articles are being edited in the future.

N O T I C ETHE INSTITUTION OF ENGINEERS,

SRI LANKA

APPLICATION FOR INCLUSIONIN DIRECTORY OF QUALIFIED

PERSONS, BUILDING SERVICESENGINEERING

According to Urban Development Authority Law No.41 of 1978,when Building Plans are submitted for approval the UDA mayrequest that such drawings are prepared by a QualifiedPerson in the field of Building Services Engineering.

In order to fulfill this requirement the IESL is callingapplications from its Corporate Members who wish to beincluded in the Directory of Qualified Persons in the saidfield. Applications can be downloaded from the IESL Websiteor collected from the IESL Secretariat.

Please note that the closing date for applications isMarch 15, 2012 and a sum of Rs 1500/- is payable by theapplicant in order to cover the cost of the directory.

UPDATING DIRECTORIES OF STRUCTURAL ENGINEERS AND ARBITRATORS - ADJUDICATORS

Copies of the directories of Structural Engineers and Arbitrators – Adjudi-cators are available with the IESL receptionist. Action is being taken bythe IESL to publish new directories. Hence kindly make changes, if any, tothe information given by you to publish those directories enabling us toinclude them in the new directories.

NOTICE

Predicting the Future!

There was an interesting article in a recent issueof the ‘Scientific American’ titled “The future isfor fools”. The article talks about the famous

predictions that had gone wrong seriously such asthe prediction made in 1943 by the IBM Chairmanthat there would be a world market for may be fivecomputers! The writer of the article however suggeststhat “It’s not predictions in general that will get youinto trouble, though. The danger lies in predicting thatthings can’t be done or will never work. Those arethe forecasts that will make you look shortsighted.”He goes on to say that “In general, it’s much safer topredict things that will happen. If you’re right, you’lllook like a genius. Take Jules Verne, whose articlesand stories described electric submarines, TV news,solar sails, “phonotelephote” (video calling),“atmospheric advertisements” (skywriting) and“electronic control devices” (tasers).Or Arthur C.Clarke’s “newspad” (iPad), Ray Bradbury’s “thimbleradios” (earbuds), Isaac Asimov’s pocket calculatorsand George Orwell’s security cameras.”

Perhaps taking advice from the writer, we could makeour own predictions about the future. In this context,may I invite our readers to send in information onwhat they perceive as to be in store for us in the future.When one looks out to the future, there will certainlybe no limit to one's imagination provided basicscientific tenets are not violated. Hence, conceptssuch as perpetual motion, though very muchinteresting, will not get qualified to be entertained.

Once again, let me invite engineers, both the youngand the old ,to send in your ideas while being mindfulto the saying “The best way to predict the future is toinvent it.”

Sri Lanka Engineering News - February 2012IESL NEWS 5

Puzzle - 47

Solution for Puzzle No. 42

UNOP Task Force47-A: The Easy One

Once I was taken blind folded to a secret underground nuclear facilityto do some maintenance work. We went down a helical staircase,which went round and round many times. I managed to determine

that the angle of descent of the staircase was 30° right through and usinga hidden instrument I managed to measure the linear length of the helicalline of intersection of the staircase and the wall of the well as 1000 ft. Howfar did we descend vertically?

Puzzle Guru Sarath ChandrasiriPuzzle Guru Sarath ChandrasiriPuzzle Guru Sarath ChandrasiriPuzzle Guru Sarath ChandrasiriPuzzle Guru Sarath Chandrasiri

47-B: The Difficult One (UNOP Task Force)

This months Difficult Puzzle was contributed by Eng Dewmini Gamlath, a newly passed outCivil Engineer, whom I mistakenly introduced as a Mechanical Engineer in a previous issue.

The “United Nincompoops Organization for Puzzles” has sent its militia for a “Regime Change”operation in “Puzzle Land”. Four troops; Alpha, Beta, Charlie (related to Potta Charlie ???)and Delta are required to cross a river by means of a ferry. This ferry can carry only two troopsat a time, and at least one troop must be on board the ferry all the time in order to protect itfrom any attack from the pro-PG troops.

Further, the troops take different durations to cross the river. Alpha can travel in one minute,Beta takes two minutes, Charlie needs four minutes and Delta consumes eight minutes forthe journey. However, when two troops are traveling at the same time, the time taken is thatneeded for the troop with the highest duration.

It is evident that the troops must cross the river within the shortest possible duration. Sincethe troops are already on their way towards the river, they have to quickly decide the order oftaking the ferry ride. And what’s more - you have just been appointed the CommandingOfficer. So, what are you still doing reading this? Work out a method and radio your troopsbefore the convoy reaches the river if you want to get rid of the Puzzle Guru...! (You canneglect the loading times.)

Happy Puzzling to All!!!

Contributed by Dewmini GamlathContributed by Dewmini GamlathContributed by Dewmini GamlathContributed by Dewmini GamlathContributed by Dewmini Gamlath

How not to Kill the Equation

Some expressed misgivings that this puzzle is too easy and below standard to bepublished in a reputed engineering journal. The results however show that it was notthat easy. Out of the 26 solutions received, only 16 were found to be correct, which

means nearly half of them got it wrong. I had a feeling that it would be so. Actually, when mycolleague Ms. Ather Sultana gave me this puzzle, I said to myself: “Hey, man, here is asimple puzzle from which we can learn a lot”. Let me explain.

Puzzle Theory: A Guru is not a genuine Guru if he does not continually spin out new theoriesin his field. Thus as a Puzzle Guru, I have started to look at puzzles in a different and moreanalytical way and it is not just for finding a solution. In science, observation and classificationare some of the means by which it can expand and develop. One of the best examples forthis comes from biology, where living things are classified in to eight major taxonomic ranksLife, Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.

It is my contention that puzzles also could be classified in a similar way. In previous issues,we have already discussed categories such as mathematical puzzles, logical puzzles,geometrical puzzles etc. In this case, what we have may be classifies as an arithmeticalpuzzle. But what is not apparent is that it belongs to a broader class called a Trap DoorPuzzle, a term that I have invented. What is a Trap Door Puzzle?

A Trap Door Puzzle: Why did so many go wrong in solving this puzzle? It is my theory thatthis happened because it is a Trap Door Puzzle. To explain let us take the correct solution,which is given below:

Original Equation:

The Correct Solution is to change one of the plus signs to a 4 as follows:

The problem is that there is another, apparently correct solution:

Contd. on page 11....

MORE ON PUZZLES 41 & 46

Puzzle 41: When I advised the readers to check forthemselves the published solution for the 3rd puzzleof P-41, it was done as a part of my vision and mission,

described elsewhere in the Puzzle Corner. You should notaccept anything without proper investigation and accept itonly when you are fully satisfied that there is sufficient groundsto do so.

Puzzle 46: There are some loopholes in this puzzle and Iwant to close them even at this somewhat late stage so thatreaders may attempt it in the right way. Some readers havesuggested using a high/low tone or male/female voice toconvey information to others. However, these methods arenot admissible because they are considered as‘communicating in other ways’, the same as touching etc.

Contd. on page 11...

TECHNO 2011

GATE ENTRANCERAFFLE DRAW WINNERS

Eng. (Dr.) Ananda Ranasinghe, President – IESL introducedthe gate entrance raffle draw for the IESL members who visited“Techno 2011”. As the Techno Chair in 2011, he introducedthis raffle draw, as a source of encouragement for themembers to visit Techno.

This draw was held on the 16th January 2012 in the presenceof the present Techno chair, Eng. Tilak de Silva together withsome members of the IESL at the Council Chamber.

Winners are as follows:♦ Eng. M P W Jayarathna - (Winner)

( A M – 7754)33/A, WaragodaAthanagalla

♦ Eng. Ananda Namal - (Second)( M – 3631)159 K, JayabimaMakavita, Ja-Ela

♦ Eng. (Prof.) M T R Jayasinghe - (Third)(M – 4382)5/3A, Nimalka GardensPanadura

♦ Eng. R C Dasanayake - (Fourth)( M – AM – 5975)53/5, KatuwamullaGanemulla

♦ Eng. G J C Gunathilake - (Fifth)( F – 789)Addl. Secretary (Engineering)Ministry of Ports and Highways9th Floor, “Sethsiripaya”Battaramulla

♦ Eng. Udaya Dampage (Sixth)( F – 938)108, Kadawatha RoadDehiwala

I am happy to say that young Eng Lanka Perera has donejust as I advised. She analyzed the solution using simplegeometry and found that the solution was flawed. The ladderis too short by about 7 inches to use the method given in thesolution.

Actually, I found that Eng Lanka and Eng VernonWeerasinghe have given a different way of reaching thefortress. They had some of the soldiers standing on the laddersas counter weights. The problem with that is that, militarilyspeaking, they are not going to survive long unless thosedefending the fort were nincompoops.

I invite all readers to look for a better solution. A nice rewardawaits you.In the meantime, congratulations Lanka on your good work.

5 + 5 + 5 = 550

545 + 5 = 550

5 + 5 + 5 = 550

Sri Lanka Engineering News - February 2012IESL NEWS6

Sri Lanka Engineering News - February 2012IESL NEWS 7

IESL WAYAMBA CENTRE

• AGM 2011 • B Paper Workshop

EVENT PHOTOS

Office Bearers of theIESL Wayamba Centre

Session 2011 / 2012Position Name & Official Address Contact Details

1. Chairman Eng. R.A.H. Rajamanthri Mobile :0773 – 852176 Email :rajanwp@hotmail.com

2. Vice Chairman Eng. Prasad Ratnayake Mobile : 0714 – 298934 Email: prasad1430@gmail.com

3. Senior Secretary Eng. Samitha N.Jayasinghe Mobile : 0714 – 950066 Email:samitha1000@hotmail.com

4. Joint Secretary Eng. Saman Piyasinghe5. Joint Secretary Lalintha Wijekoon6. Treasurer Eng. S. M. B. Dissanayake Mobile: 0777 – 480184

Email : mckg@sltnet.lk7. Assistant Treasurer Eng. M. D. K. Mahiti8. Editor &Web Master Eng. M. I. M. Irshad

9. 1st Committee Member Eng. Ms. Chitra Nissanka (Past Chairperson)10. 2nd Committee Member Eng. Ms. Mangala Tennakoon (Past Chairperson)11. 3rd Committee Member Eng. Bandula Witharama ( Past Chairmen)12. 4th Committee Member Eng. Rohitha M. Thanthilage13. 5th Committee Member Eng. Kapila Weerasooriy14. 6th Committee Member Eng.Kusum Priyananda15. 7th Committee Member Eng. Sunil Jayatissa16. 8th Committee Member Eng. J. M. W. K. Hunukumbura17. 9th Committee Member Eng. D. M. B. Dissanayake,18. 10th Committee Member Eng. Ms. A. D. S. Priyadarshani,19. 11th Committee Member Eng. P. V. J. Fernando,20. 12th Committee Member Eng. K. A. D. Indika Ratnayake,21. 13th Committee Member Eng. B.M.L.S. Bandaranayake22. 14th Committee Member Eng. W.C.P. Warnakulasooriya

• Contract Administration - Full day Seminar

Representatives of the NameOrganization

23. Road Development Eng. Sudesh Perera, Authority

24. National Water Eng.Ms. Geethanjali Supply & Drainage Gunathilaka Board

25. North Western Province Eng. Salinda Bandara Engineering Department

26. Ceylon Electricity Board Eng. Ramal M. Amadoru

27. Irrigation Department Eng. B.V. Indrapala

28. Provincial Road Eng. Rasika Development Mallawaarachi Department

29. Private Sector Eng. H. G. N. Nalin (Kurunegala District) Pathirana

30. RDA – PuttalamDistrict Eng. P. Chares Jugin

Sri Lanka Engineering News - February 2012IESL NEWS8

w. k.rh fjk;lgw. k.rh fjk;lgw. k.rh fjk;lgw. k.rh fjk;lgw. k.rh fjk;lgjr,;a bxðfkare" ÿ,sma .=Kj¾Ok úisksjr,;a bxðfkare" ÿ,sma .=Kj¾Ok úisksjr,;a bxðfkare" ÿ,sma .=Kj¾Ok úisksjr,;a bxðfkare" ÿ,sma .=Kj¾Ok úisksjr,;a bxðfkare" ÿ,sma .=Kj¾Ok úisks

10 jeks msgqjg'''''

ìfidafldgqfõ ìfidafldgqfõ ìfidafldgqfõ ìfidafldgqfõ ìfidafldgqfõ ‘;d;a;aúl;d;a;aúl;d;a;aúl;d;a;aúl;d;a;aúlld¾hld¾hld¾hld¾hld¾h’ iy w;d;a;aúl iy w;d;a;aúl iy w;d;a;aúl iy w;d;a;aúl iy w;d;a;aúl

ukia.d;ukia.d;ukia.d;ukia.d;ukia.d;!jr,;a bxðfkare lms, mSßia úisksjr,;a bxðfkare lms, mSßia úisksjr,;a bxðfkare lms, mSßia úisksjr,;a bxðfkare lms, mSßia úisksjr,;a bxðfkare lms, mSßia úisks

ìfidafldgqfõ l%shdldß;ajh iïnkaOfhkaìfidafldgqfõ l%shdldß;ajh iïnkaOfhkaìfidafldgqfõ l%shdldß;ajh iïnkaOfhkaìfidafldgqfõ l%shdldß;ajh iïnkaOfhkaìfidafldgqfõ l%shdldß;ajh iïnkaOfhkafuu ,smsfha m<jk lreKq ixjdohg újD;hsfuu ,smsfha m<jk lreKq ixjdohg újD;hsfuu ,smsfha m<jk lreKq ixjdohg újD;hsfuu ,smsfha m<jk lreKq ixjdohg újD;hsfuu ,smsfha m<jk lreKq ixjdohg újD;hs

- ixialdrl - - ixialdrl - - ixialdrl - - ixialdrl - - ixialdrl -

ìfidafldgqj hkq ‘Valve pit’ yd$fyda ‘Surge tank’ hkfn%daysh¾,df.a iy mdl¾,df.a idjoH Wml,amk j,skawfma fndfyda fokd ;ju;a ñ§ ke;' ìfidafldgqfõld¾hNdrh jkafka jeä Wilg c,h re|jq jeõj, c,mSvkh jElkao yryd hk fidfrdõjg n,mEuwvqflreuh' fï ksid jE lkao wdrlaId fõ' fï ms<sn|jw;d;aúl ld¾h (virtual work) kue;s ksõgkaf.a fojeksiy f;jeks kshu u; iy Y=oaO .Ks;fha m%fïhhkalSmhla u; muKla mokïj f.dv ke.= ixl,amh Tiafial< ú.%yhka ‘úÿir’ ckjdß 18 od l,dmfha we;' wjYHwfhl=g th n,d.; yelsh' fïjd wOHhkh fkdlr;ekska ;ek wyq,d.;a oEu; mokïj m%ldY ksl=;afkdlrkafka kï uekú' wjldY ,efnkafka kï by;i|yka l< mßÈ b;du;a uq,sl ixl,amj, (very Basicconcepts) isg ìfidafldgqfõ (iy wjYH kï wm ,shdlshd we;s wfkla oEys) l%shdjka ms<sn|j IESL ys foaYkhlameje;aùug ud iqodkïh'

by; m%Odk ld¾hNdrhg wu;rj we;eï ìfidafldgqfodr r|jk f,io l%shd l<d úh yel' tfy;a ;ju;ata ms<sn| ksYaaÑ; mqrdúoHd;aul idlals ke;'

tfia jqjo fïjd ‘surge tank’ f,i ls%hd flreug kïfï fodrgq fõ.fhka wßk jyk ;;a;ajfha tajdo úhhq;=h' tjeks wjYH;djla wmg fmkajd,sh yelso?ìfidafldgqfõ ld¾hNdrh r|dmj;skafka c,fhaÿiai%dú;dj (viscosity) iy ì;a;sj, >¾IKh u;h' thiq¿mgq ldrKhla fkdfõ'

SLEN ixialdrl;=uks, SLEN ys úIhdkqnoaO oEiïnkaOfhka hï ,smshla m<jkafka kï tys hï fydaYdia;%Sh Ndjhla iy ix.; njla (Consistency) mej;shhq;=nj wmf.a woyihs' wka;¾cd,h Tiafia ,nd.kakdf;dr;=re cxcd, ;=< j,au;a ù ,shefjk m,ayE,s j,skaSLEN wmú;% jkq oelsug wm wlue;sh' f;dr;=re;dlaIKfha m%;sM, jk Bkshd presentation j,ska iyReport writing j,ska ñ§ kej; uq,sl ixl,amj,g wmhdhq;= ld,h t<U we;'

ñys;,h u; kEu foaYhl w.k.rh" rcfhys n,mrdl%uhr|k tys ck;d ksfhdað;hskauqk .efik ia:dkhhs' Y% S,xldfjys w.k.rh" ñys;,fhaw.kqjrlg ysñ §¾>;u kduhjk fldaÜfÜ - Y%S chj¾Okmqrhñi fldf,dïmqrh fkdjk njisysm;a úug ksfïIhla .;fjhs'

jrdh m%uqL lr.;a fld<Uk.rh fj<| uOHia:dkhlaf,i l%ufhka úldYh úh' thmD;=.SiSkaf.a yd ,kafoaiskaf.an,h leálr.;a fufyhqïfmd<hs' ì%;dkH hq.fha§ th w.k.rh jqjd muKla fkdj" 1865jeks wE; ld,hl isg fld<Uuyd k.r iNdj m%Odk m,d;amd,k wdh;khla f,i jHqy.;ú mej;=ks' fld<U k.riNdfjys n,h oekg;a fojeksjkafka uyd wdKavqjg muKs' wmksoyi ,nk úg th b;du;aixúOdkd;aulj mßmd,kh jq"is;a .kakd iq¨ k.rhlajmej;=ks' 19 jk ishjfia w.Nd.fha isg msßisÿ mdkSh c,moaO;shlao" 20 jk ishjfiaukdj ls%hd;aul jq u< kd,sldmo aO; shl ao ty s j q w;r"ms<sfj,lg yev.eka jqKq"jdykj,g ;onohlska f;drj.uka l<yels uyd ud¾.moaO;shlao tys úh'

ysgmq isx.mamqre kdhl ,S lajdkahq' 60 oYlfha uq, Nd.fha§isx.mamqrejg fld<U wdlD;sh,nd §ug W;aiql jqfha funeúkaúh hq;=h' fld<U k.rfhaj¾Okhg wkqrEmj" ty sbvlfvys iSñ; nj ms<sn|jk.r m%OdkSkaf.a wjOdkh fïhq.fha§ fhduqúu fya;=fjka Bgwdikak m%foaYj, ìï fmfoiaúáka úg fld<Ug hd flreKs'fíia,hska mdfrka kef.kysrghdno le<Ks .f.ys W;=re fldkabiõj fldf<dïmqrhg hd jqfhatf,isks' f,dal ck.ykh jir30 l§ fo.=k jk njg fïld,fha§ .Kka ne,sk' fuuwkd.; wNsfhda.hg wjeis f,ik.rfha yev;, ieliSugwmyiq úh yels j. ÿgq neúkak.r ks¾udmlfhda fufia tysjmißh m q¨, a l sÍugfhfokakg we;' tkuqÿj¾;udkfha fld<U k.rfhysukao.dó r:jdyk m%jdykh"jdyk .d,a lsÍfï wvq myiqlï"wju l%Svdx.k myiqlï fukauldKq moaO;shg u< my W;=rdhEï" f.dv .eiqKq l=Kq lkao,ayd ks;r isÿjk .x j;=r jeksfya;=j,ska" mÈxÑ ù isàugwmyiq ;;ajhka we;s lrjk iqnjla fmkajhs'

oekg rdcH kdhlhd wdrlaIlfya;=u; w.ue;s ksjfiysfjfi;;a tu ksjfiys óg¾100l jgmsgdj b;d oeä f,iWfrka Wr .efgk ckldhlskaWia f.dvke.s,s j,ska u< c,fmdïmd.dr ÿ.| yuk fmdl=Kq"fvdaì uOHia:dk yd f;a lvj,ska .yk jq m%foaYhlska jgù ;sìu" w.k.rfhys bvlvfkdue;slu wjOdrkh úh hq;=nj ukd fia mila lr fohs'

70 oYlfha w. Nd.fha§ ysgmqckdêm;sjrhl=" w. k.rhfld<Ug hdno Y%S chj¾Ok mqrhnjg m%ldY lf,a" th ish

kfuys fldgila jqjd fukau by;lS ienE ;;a;ajho mila lr .ksñkaúh yelsh' j¾;udkfhaÈ fuu k.rfolu taldnoaO ú we;s fihlafmfkkqfha tu k.r w;r udhsïwúksYaÑ; lrjñks' w.k.rh kduud;%slj fjkia jqjo tys§ uydmßudK f,i fj<| lghq;= fydald¾hd, n,dfmdfrd;a;= jq f,ifld<ôka neyer fkdjqjd muKlafkdj" tu fõ.ho l%ufhka wvq jqnj fmfka' Y%S chj¾Ok mqrhiajdNdúlju ixj¾Ok ld¾hhkagkqiqÿiq .s,d neish yels j.=re ìuls'tys ixj¾Ok ld¾hhka oeä f,ibvï f.dv lsÍfuka isÿ l<fya;=fjka" wo jk úg k.rhjeäukla oeä f,i c,h neifkdhEfï ;¾ckhg uqyqK md isà'fuys bÈl, kj md¾,sfïka;=j fïjk úg tla jrla fyda c,fhkahg ú ;sfí' fï wkqj b;d fláld,hla ;=,§ Y%S chj¾Okmqr -fld aÜfÜ k.rh Y% S ,xldfõw.kqjr ùug kqiqÿiq nj ikd: ùwe;'

fld<U k.rfha N+f.da,Sh ;;ajhmsßlaiSfïÈ" th ;j ÿrg;a mq¿,al< fkdyelsfõ' th W;=ßka le<Ks..g udhsï jk w;r ngysßka uydid.rhg udhsï fjhs' ol=Kska ydkef.kysßka th fnd,af.dv j.=reìï j,ska yd we, ud¾. j,ska wjysrlrkq ,nhs' th l=vd ÿm;a lsysmhlaf,i l,ska mej;sho" ol=Kska ydkefkysßka msysá j.=re ìï mqrjdwe;s neúka tu l=vd Èjhska woolakg ke;'

fld<U jrdh wjysr lsÍfuka ydk.rhg msúfik md,ï lsysmhlaw;am;a lr .ekSfuka" ´kEufufyd;l fld<U k.rhwkdrlaI s; l sÍug i;=rewdl%ukhlg yelshdj ;sfí' tjkafudfyd;l .=jkska wjYH iemhqïuyd mßudKfhka ,nd Èh fkdyelsw;r" tho l< yel afl afy,sfldmag¾ wdOdrfhka muKs'msg;ska k.rhg m%úYaG jk c,iemhqï k, fudfyd;lska lmdyeßh yelsh' k.rh ;=< lsisÿ wdydrksIamdokhla isÿfkdjk neúka"jeg,Sul§ k.r jdiSka ksrdydrj;nd, Su wmyiq ke;' ^fuhmD;=.SiSkaf.a fld<U n,h ì|,Sui|yd isxy,hka fhÿ id¾:lWml%uhls& k.rh ;=< úÿ,shWmoùfï yelshdj we;;a" Bg wjYHbkaOk msg;ska f.k wd hq;= fjhs'tys we;s ksjdi iy ck.yk>k;ajh wdrlaIdj ms<sn| ìhlreisysk ujhs' fï wkqj fld<Uk.rh yÈis ;;a;ajhl§" iajNdúlwdmodjl§ fyda hqo ;;a;ajhl§uy;a fia wkdrlaIs;h'

blaukska fyda ld,hdf.a wejEfukaisÿúh yels f.da,Sh jYfhka we;su qy qÿ c, uÜgu by, hdfï;¾ckh yuqfõ" hdmkh w¾Ooaùmhyd fld<U k.rh uqyqÿ c, LdokwjOdkulg nÿka úh yels w;r"Bg tfrysj yd uev meje;aúuglrkq ,nk úhoï wyi Wigúysfokq we;' oekg;a wfkl=;aÿïßh ud¾. yd ii|k úg fld<Uud;r uqyqÿ nv ÿïßh ud¾.h kv;a;=lsÍug wêl;u úhoula oeÍugisÿfjhs' wm l=vdjqka f,i fi,a,ïl< fjr< ìï ;Sr wo olakg ke;'tu fmfofia fjr< ixrlaIKhi|yd uyre l¿.,a neñ fhdodmqrjd we;' flfia fj;;a uqyqÿ nvÿïßh ud¾.h wdrlaId lsÍfï

ikd;k wr.,hl fh§ugisÿj we;;a" fudaiï iufha tuish¿ jeg lfvd¨ mrhñkaid.rh úiska ÿïßh ud¾.hfj,d .ekSu ksid ÿïßh.ukd.ukh ukao.dó lrjhs'

idfmalaI jYfhka fkdokakdlreKla jkqfha wÈka jir17000 lg fmrd;=j id.rc,fha uÜgu oekg jvd óg¾140la muK my,ska jq njhs'taldldÍj uqyqÿ uÜgu by,fkd.sho" id.r c, uÜgutla ish jila ;=,§ óg¾06lg jvd by,f.dia we;snjksÍlaIKh lr we;' ie<lshhq;= jkqfha tfia isÿù we;af;afmdis, oykh lrkfldg.;af.da,Sh Wkqiqï ùu mßk;fkdjqKq ld,hl úuh'

uqyqÿ uÜgu tla tallhlskaby, hkúg tys ;sria ÈYdn,mEu ish .=Kfha isg oyia.=Khla jk nj idudkHÍ;shls' fuu ksÍlaiK j,gwkqj" my;a N + f.d a, ShifudaÉp uÜgfuys n,Yla;sn,d.dr yd l¾udka;bÈlsÍfuys,d ie,iqï h,súuish hq;=j we;'

Èjhsfkys N+ úIu;d ,laIKj,g wkqj uqyqÿ c, uÜgfïjeäùu .xj;=r ;¾ckhlgouq, mqrhs' mj;sk ifudaÉpuÜgï fkdi<ld bÈlr we;shá;, myiqlï fuu;¾ckhg ksr;=re uqyqK fokqwe;' idod we;s uydud¾."f.dvke.s,s" yd j.=re ìïf.dvlsÍu fy a; =fjka "wfm al aI s; i Sudk a; slld<.=Ksl ;;a;aj yuqfõ" .xj;=r ;¾ckh ;j ;j;a WÉplrjhs'

ksrka;rfhka c,h Wlyd.kakd neúka" .x.dj, c,hisf|k ld,j,§ wiSñ; f,ickdlS¾K ksß;È. m%foaYj,mdkSh c,hg ¨Kq c,hñY%ùfï m%jk;djla ;sfí'oekg uyfld<U m%foaYhgmdkSh c,h imhkq ,nkle<Ks .f.ys wU;f,a l=¿uf.ys c,h fmdïm lsÍufmnrjdß$ud¾;= hk ld,iSudfõ§" by; lSfya;=j ksidwe;eï úg Èklg mehlsysmhlg muK úfgka úgk;r lsÍug isÿfjhs' wkqfõoYlh ;=, ksr;=reju fuujdr .Kfkys jeäùula olakg,enqKq w;r" 2009 § m<uqj;djg ckjdß udifhaÈ o ;=¿uf.ys fmdïm lsßug iSudmeKúks' 2009 fmnrjdßudifha§ fnka;ßka Tíngc,h imhk l¿ ..fl;afyak c, ;=¿ u.o tufya;=j ksidu jid oeñKs'.d,af,a .sx .. ;=¿ ux ia:dkl%ufhka .f.ys by, m%foaYlrdfhduq lr we;s w;r" ud;rks,aj,d .. biau;af;ysbÈjqKq ;=¿ ux ia:dkhotf,iu by, m%foaYj,gfhduq flreKs'

oekg Y%S ,dxlslhkg .skslÿmsmsßu yd N+ñ lïmd ms<sn|jt;rï j.la ke;' tfy;afmda,a B mSßia úiska rÑ;.%ka:hla Wmqgd olajk cd;sl

IESL BENEVOLENTFUND

The IESL Benevolent Fund provides much neededrelief to members and their families rendered dis-traught by unfortunate events.

The fund, at present, offers financial assistance upto Rs 60,000/= in the event of sudden death / sick-ness of a member, unexpected and serious loss ofincome to a member or any other cause which theBoard of Management of the Benevolent Fund con-siders as deserving such assistance.

All members, irrespective of class of their member-ship and regardless of their contributions are eligibleto be beneficiaries of the fund. Appeals for financialassistance from the IESL Benevolent Fund shouldbe channeled through the Executive Secretary byfilling out the form specified for the purpose which isavailable on request.

Sri Lanka Engineering News - February 2012IESL NEWS 9

THE INSTITUTION OFENGINEERS,SRI LANKA

Competition

on“Water Resources Developmentand Future Challenges”- Role of

Engineering meeting FutureChallenges of Water Resources

Development in Sri LankaSession 2011 / 2012

Sponsored byInternational Water

Management Institute(IWMI)

We are pleased to announce that arrangements are beingmade for the forthcoming Competition on WaterResources Development sponsored by IWMI towardsthe Annual Sessions of IESL in October 2012. The prizeswill be given for the two best Technical Papers under theabove mentioned theme prepared for this competitionby Associate Members & Corporate Members of IESL.Jointly authored papers will be accepted, provided atleast one of the authors satisfies the above criteria.Papers must be original and demonstrate the author’sknowledge and experience of the subject. The awardwinning articles will be published in the journal,“Engineer” of the IESL.

Water is a vital input in industrial, energy, tourism,recreational, navigation, agriculture, forestry, livestockand fishery sectors. As water scarcity grows, competitionamong sectors and users, and between the human needsand the environment intensifies. Effective and efficientwater management is therefore a prerequisite forsustainable socio-economic development.

The paper can address extraction, storage, distribution,use and disposal issues in any economic sector. Itshould illustrate how engineering and technology isapplied in increasing productivity, in balancing supplyand demand of water and/or in reducing water pollutionand protecting freshwater ecosystems.

Preference will be given to papers of an empirical andanalytical nature based on primary and/or secondarydata although papers addressing topical issues throughconceptual development may also be forwarded.

AWARDS & PRIZES(A) Rs. 45,000.00 - For members ofIESL over 35 years of age on 01 October 2012

(B) Rs. 30,000.00 - Engineeringgraduates holding membership of IESL and35 years of age and below on 01 October2012007

Intention to participate in this competitionshould be intimated to us along with your bio-data & the full Technical Papers on or before30 May 2012. IESL form IWMI/1 should be usedfor this purpose.

Further information could be obtained from theChairman, Steering Committee on WaterResources Development of The Institution ofEngineers, Sri Lanka, on Tel: 072- 3421493 orPublicity Officer-IESL 011-2685490, 011-2698426 or 011-2699210, ext-232, 207,E-mail: dir.pub@iesl.lk, ieslpub@gmail.com,Fax : 011-2699202

THE INSTITUTION OF ENGINEERS,SRI LANKACompetition

on

“Eco Efficient Water Infrastructure for SustainableDevelopment – Experiences gained from IntegratedWater Resources Infrastructure Development in Sri

Lanka”Session 2011/2012

Sponsored by

St. Anthony’s Industries Group (Private) Ltd.(MANUFACTURES OF ANTON PVC PIPES AND FITTINGS)

Two competitions will be held this year for the award of certificates and cash prizes. Thecompetition soliciting original Technical Papers on research and case studies are acceptedfrom members of IESL who are above 35 years.

There will also be another competition for members who are 35 years and below on 01October 2012. This competition is open to members of IESL and final year students ofFaculties of Engineering of Universities in Sri Lanka who are student members of IESL orwho obtain such membership before submitting their technical papers.Closing ate

AWARDS & PRIZES 2007

ABOVE 35 YEARS ON 2012.10.01 35 YEARS AND BELOW ON 2012.10.01First Prize - Rs. 50,000/= First Prize - Rs. 25,000/=Second Prize - Rs. 25,000/= Second Prize - Rs. 15,000/=Third Prize - Rs. 10,000/= Third Prize - Rs. 5,000/=

The members (Fellows, Members, Associate Members, Associates, Companions and Students)who wish to participate must obtain the application forms from IESL and submit bio data &full Technical Papers to reach the Executive Secretary, Institution of Engineers Sri Lanka,No. 120/15, Wijerama Mawatha, Colombo 07 on or before 30 May 2012.

Further information could be obtained from the Chairman, Steering Committee on WaterResources Development of The Institution of Engineers, Sri Lanka, on Tel: 072- 3421493or Publicity Officer-IESL 011-2685490, 011-2698426 or 011-2699210,ext- 232 , 207,E-mail: dir.pub@iesl.lk, ieslpub@gmail.com, Fax : 011-2699202

Notice for all member categories:Membership Subscription Payments and Receipt of Publications

Council of the IESL has decided to strictly implement the following conditions regarding thereceipt of membership subscriptions and the issuing of publications.

1. If the subscription for the particular year is in arrears by 31st March of the same year, issuingof publications to that member will be stopped from that day onwards.

2. If the subscription for the particular year is in arrears by 31st October of the same year, thenthe name of that member will be removed from the IESL membership roll according to theBy-laws of the Institution.

………………………………………………………………………………………………………………………………………………………………..

For the attention of the applicants for memberships

(A) Submission of membership applications:

Applications for All membership Categories (Including Transfers):

Duly completed membership applications for all member categories (including the transfers)are accepted at the Membership Division of the IESL on Mondays, Tuesdays and Fridays (butnot on holydays which may fall on these days).

All applicants are kindly requested to refrain from coming to IESL for such submissions onWednesdays, Thursdays and during week-ends.

(B) Applications/Transfers to “Member” category:

All Engineers who wish to apply for the Corporate Membership (To obtain Chartered EngineerStatus) are advised to read the “Professional Review Rules” of the IESL.

(Available in the Website)

All applicants are supposed to do a self assessment with reference to the “ProfessionalReview Rules” before submitting an application.

Those who really need further clarification may write (Emailing is ok) to The Executive Secre-tary – IESL

or

Meet the Director (Membership), but restricting to above 3 days (Monday, Tuesday and Friday)of the week.

Sri Lanka Engineering News - February 2012IESL NEWS10

8 jeks msgqfjka'''

w. k.rh''''w. k.rh''''w. k.rh''''w. k.rh''''w. k.rh''''

is;shï fmd;" fuu j.la ke;sfkdie,ls<su;a núka msìoùuglreKq f.kyer mdhs' mSßiaf.azzmD;=.SiSkag hg;a ,xldjZZ(Ceylon Under the Portuguese)kï jq .%ka:h wkqj 1615 wfm%a,a14 Èk rd;%sh" i,afmaÜ .sksl|ïN .s.srE uyd úkdYldÍtlla jq w;r" we;s jq .skscd,djg ueÈj fld<U k.rjdiSka fooyila muK ñhf.dia we;s nj jd¾:d flfrhs'^ví,sõ' ta is,ajdf.a —úchndfld, a,h˜ l:dkdhl—khkdkkao˜ rcjdi, isrf.oßka mek hkafka fuuisoaêfhka miq k.rfha isÿjkl,ne.Eksh u; ,efnkwjirhlsks&' oekqÿ ,xldfõf.dvke.s,s N+ñ lïmdjlgTfrd;a;= fok whqßka ie,iqïfkdflf¾' l¿ k;a;,f,iskao ye¢kafjk 1957foieïn¾ ui ksudjla ke;s uydjeis .¾ckd we;slr jq w;rthska iod ;snq msh.eg" jeõ"fõ,s hkdÈh leãì£ .sfhah'fuu neñ óg¾ 15lg jvd Witajd fkdùh' h,s;a fujekswdmodjla" N+ p,khla fydakdhhdula fya;=fjka wo mj;skc, úÿ,s n,d.dr fõ,s ì£ulawe;sjqjfyd;a" bka wk;=rejisÿúh yels uyd c, l|ln,mEfuka isÿúh yels úkdYhw;suy;ah' uyje,s yd le<Ks.x.d yryd fujeks neñ ydfõ,s fndfyduhla ne| we;'fld<U k.rh iqrlsug ne¢le<Ks .x.d neïu mrhd c,hW;=rd hdfï wjodku oekg;amj;sk w;r" th by; ls oreKqwjodkug lsisfia;a uqyqKÈhfkdyels ;;a;ajhls' fld<Uk.rhg c,h imhk m%Odkc, k,h 19 jk ishjfia§bÈlrk ,o afo a yxje, a,j.=reìu yryd f.dvke.= miaf.dve,a,lska hq;a neïula;=,h' 1930ia .Kka j,§ ufld<U c, l¾udka;bxðfkarejrhd jd¾;djlskaksÍlaIKh lf,a fuu neïufya;=fjka j.=re ìug c,h neihdu iSud jq neúka .x j;=r;¾ckh jvd;a W;aikakj isÿùwe;s njhs' Èjx.; wdpd¾h t'tka 'ti a ' l =,i sxy uy;dmejiqfõ yhsf,j,a ud¾.fhabÈlsÍïo fujeksu ;;a;ajhlaWodl, njhs' fï wkqj wkqudkl, yelafla lgqkdhl wêfõ.sOdjk ud¾.h fukau olaIsKuyd ud¾.ho bÈ lrKq ,nkafkaN +ñh u;sk a ñi lKqu;fkdjk neúka" tjeksu úmdlh<s;a we;súh yels njhs'

1986 fidaúhÜ foaYfhys isÿjqKqp¾fkdì,a kHIaál wk;=ßkafylaghd¾ 300"000 l m%foaYhlck;dj bj;a lsÍug isÿúh'fpkakdhs k.rfhys msysgd we;skHIaál n,d.dr fld<Ugt;rï wE; fkdjk w;r"bxÈhdfõ ;ñ,akdvq m%dka;fha;j;a tjeks n,d.dr bÈlsÍughhs' iqkdñhl ìhlre nj ñksiayo ika;dkhg oefkkakg.;af; a 2004 foieïn¾udifhka miqh' 1950 .Kkaj,§ wyi Wig úyso .sh uqyqÿc, ;rx. jd¾:d l< we,ialdiqkdñh fndfyda fokdf.au;lfhka úhelS ;snqKs' kdúl.uka ud¾. j,ska wE; id.rh

ms<sn| ksÍlaIK o;a;hka uE;la jk;=reu m;,j fkd;snqKo" pkaøsld;dlaIKh wjÈùu;a iu." uydid.rfha fuf;la fkdÿgq uydwkqoelSu werUqKs' 70 oYlfhafidaúhÜ wNHjldY.dókag .=jfkaúúO ia:dkj, isg ksÍlaIKhlsÍfï§" úúO uÜgï j,g id.rhWia my;a ù ;sìu oelSu l=;=y,hlaúh'

N+ wNHka;rfha we;s ia;r ,siaidhdulska fyda úi,a W,aldmd;hla.eàfuka fyda id.r m;af,a we;sjkkdh hEulska we;sjk iqkdñhlgjvd;au nªka jkq we;af;a ckdlS¾Kjq uqy qÿ nv m%fo aYhs ' fujkajHikhla tljr f,dj m qrdwe;sjqjfyd;a n,dfmdfrd;a;= úhyels wdOdr iSudiys;h' tneúkafujeks úm;a j,g Tfrd;a;= §ugyelsjk f,i rgl fomd iúu;aúh hq;=h'

wêiq¾h rYañ l|ïN mD;=úfha úúOia:dk j,g wfkalúo n,mEïlrhs' th iEu jir 11g jrlau WÉpfjhs' tf,i n,j;a jk 24 jkjdrh f,i ie,flk ó,. jdrh2012 § meK kef.k njla lshefõ'fuu wê iq¾h l|ïN n,mEfukauy;a jq iq¾h l=Kdgqjla we;sjknjla i|yka flf¾' 1989 § fuuWmßu ;;a;ajh we;s jq w;r tys§lekvdfõ wê n,e;s úÿ,s reyekaj, re¢ ysu l=Üá j, wêNdrhfya;= fldg tu úÿ,s reyeka ì£f.dia" miqj wkql%ufhka reyeka re¢l=¿Kq tlska tl lvd jegqKs'

1859 § o fuf,iskau we;s jq ;;a;aju; úÿ,s ixfoaY úlD;s f,il%shd;aul jq w;r" tys cks; Yla;shfya;=fjka ndysr Yla;s m%Nj j,msysgdOdr fkdue;sj úÿ,s reyekau.ska ix{d l%shd;aul lrkakg yelsúh' iSudka;sl iq¾h l%shdldß;ajhfya;=fjka pkaøsld ;dlaIKh l%shdúrys; úh yelsh' thska wka;¾cd,hcx.u ÿrl:k" úYaj msysgqùfï l%uh^GPS&" ksYaÑ; fydard o;a; udmlhkdÈh laIKhlska wfydais ù f.diaish,a, wl¾ukH ùfï ;;a;ajhlaowe;s úh yelsh' j¾;udkfhawka;¾cd, fõ.h wvmk jq úgmjd ueisú,s k.k we;a;ka" tu;;a;ajhlg flfia uqyqK mdkafkaoehs hkak is;kakgo fkdyelsh'

'iEu pl%hl§u iq¾hd ish O%ejfjkia lrhs' fuf,iskau mD;=úhopqïnl O%ejo fjkia ù we;s njfmfka' ^;ekam;a ù we;s hlvwxY+kaf.a ÈYd .; ùu wkqj& fuuO%ej fjkiaùfï ó,. jdrhg oekgfndfyda fia l,a bl=;a ù we;'pkaøhd isg we;s ÿr m%udKh" ndÈhjvÈfhys fjkia ùug n,mEufukau" mq¾K pkaøhd yd ine¢"ñksia isõmd yeisÍï fï jk úgukdj wOHkh lr we; mD;=úh jgdixprkh lrk wfkl=;a .%yhkaf.an,meï ms<sn|j úúO u;su;dka;rmj;S' f.da,Sh WKqiqï úu" fmdis,oykh ùu muKla fya;=fjkawe;sjk nj lshefjk .d,f.daÜáhksid" i sh, a, t alrdY Sj wmgfkdoefkk fia isÿúh yels fjk;aúkdYhka ms<sn|j wm fofk;a wkaOù we;'

udkj j¾.hd keue;s i;a;ajhd úiskaoykh lrkq ,nk fmdis, bkaOk"f.d a, Sh WKqiqfuys j¾Okhgie,lsh h q; = odhl;ajhla,ndÿkafkao fkdÿkafkao hkaktÈklg jeo.;a fkdjkq we;' uqyqÿc, uÜgfuys ke.Su" úi,a neñ ì£hdu" c, m%Njhkg ¨Kq Èh uqiqùu" ld,.=Ksl n,mEï" .x.dfof.dv;,d hdï" iqkdñ úm;a" ñksia

l % shdldß; aj úm;a iy.sKsl÷j, ÿudrh jeksje,el aúh fkdyel s;;a;ajhkag" yev.eiSug ydie,i qï l sÍug ukqIHixy;shg olaI;djh we;'fujeks ish¿ úm;a yd yÈis;;a;ajhkaf.a n,mEu jvd;a;Èka oefkkq we; af; ackdlS¾K jq iuqÿr wdY%s; my;aìï fmfoia j,gh' tjeksúkdYldÍ ;;a;ajhla we;sfkdjqjo uqyqÿ c, uÜgfuysby, hdu;a iu. ty sn,meug fujeks my;a ìïfmfoia l%u l%ufhka yiqjkqwe;' fldamkafya.ka fidhd.eksï j,g wkqj 21 jkishjfia§ f,dalh ;=, ñkafmr fkdjq úrE ld,.=Kslfjkiaúï fya;=fjka isÿjkixl%uKhka ms<sn|j wk;=rew.jd we;' b;sydifhys u;=ù we;s fujka ;;a;ajhkaf.kamdvï bf.k fkd.kS kï" tau;af;ys re¢ ÿ¾úmdl ú£ugñksidg isÿjkq we;' fujeks;;a;aj ms<sn|j b;sydifhkaW.; yels mdvï fudkjdo@

1755 § w;a,ka;sla id.r m;af,aisÿjqk kdhhdu fya;=fjkamek ke.=k oreKq iqkdñfhka"mD;=.d,fha ,sianka w.kqjruq¨ukskau úkdY jqfha tysmej;s rdclsh yd fj<|uOHia:dk n,h uq,skqmqgdouñks' fuhska blaì;sjiamd[a{h úiska fn,ySk jqmD;=.d,h wdl%uKh lrk ,§'mD;=.siS wêrdcHh ì|jeàuwdrïN jqfha fu;ek isgh'B,. jir jk 1756 ÈumD;=.d,h i;=j ;snq ,xldfõn,h ,kafoaiskg ndrfok,§'

m<jk ishjfia§ —fjiQúhia.sKslkao msmsÍu;a iu. we;sj qK q ÿudrfhka m %u qÈ;k.rhlaj mej;s fmdïfmhsk.rh úkdY úh' h<s;a jrla19 jk ishjfia§ .fõYkhlrk ;=reu th ck;djf.au;lfhka .s,syS mej;=ks' 1861§ weußld tlai;a ckmofhacks; —fmd aks tlai am %i a˜ikafoaY fiajh thska udi 18lajeks ál l,lÈ fg,s.%d*ajh¾ys fidhd .ekSfuka miquq¿ukskau wfydais ù .sfhah'fojeks f,d al hqo aOfha§m%:ufhka ueÈy;aj l% shdfkdl< weußld tlai;ackmoh m¾,a jrdhg cmkqkaúiska fndaïn oeófuka miq"wkfm al aI s; f,i Bgwj;S¾Kh ù" mrudKq fndaïnyd kHIaÀl wú Ndú;d lrñka"hqoaOh wjidkfha§ ;j;a iS;,hqoaOhlg uq, msÍh'

by; lreKq j,ska fmkShkafka b;d flá ld,hla;=<§ yd b;d wkfmalaIs;wkaoñka b;sydifhys .uka u.fjkia lrj q fmr< sldrisoaëkah' úkYldÍ isoaëka b;dwkfmal aI s; i a:dk ydfj,dj, i sÿjk w;r"oejeka; fjkia lsÍï j,g uq,mqrhs'

foaYmd,k yd wd¾Ól n,htlaj leáj we;s rgj," tufoaYmd,k yd wd¾Ól n,htl úg wl%sh úfï ie.jqkqwdka;ßl ,laIK wdfõKsljmj;S ' tjeks úkdYldÍwjia:djl we;súh yels;;a;aj j,ska m%fhdack .ekSug

n,;kaydfjka fmdmshk n,j;a;=W;aidy lr;s' n,h fjka fjkajYfhka mej;=kfyd;a tla ;ekln,h wka;rdjlg nÿka jq úgwfkla n, ia:dkhg th h,smqnqod,sh yelsh'

foaYmd,k yd wd¾Ól n,hmj;ajd .ekSfï jvd m%;sM, odhll%uh jkqfha tu wxY folfo;ekl ;sìuh' túg fuu rYañl|ïN j,g tlsfkldf. afijke,s fkdjÈk neúka tajdgfjka fjka jYfhka ia:djr ùugyelshdj ,efí' fufia jq k.rj,g fnfyúka WodyrK we;'bkaÈhdfõ È,a,shla-uqïndhs;a"úhÜkdufha yefkdahs-fydaÑx ú"Ökfha fnhsðka -Iekayhs" weußldtlai;a ckmofha fjdIskagka -ksõfhda¾la yd fko¾,ka;fhaweïiag¾vEï - fya.a hk k.rlÈu WodyrK fjhs'

by; ;;a;aj ie,lsfï§ Y% S,xldfõ w.k.rh jvd iqÿiqi a:dkhl fhdod .ekSfïjdisodhl nj úuisu jà' fuf,iw.kqjr fjk;lg fhduq lsÍfï§jeäukla jYfhka jdis iy.;njla we;sjk mßoafoka tu kjk.rh ie,iqï l< hq;=h' fld<U$ Y%S chj¾Ok mqr hk k.rfuf,i ÈhqKq úug ndOd we;s jkfia msysgd we;'

kj k.rh by; i|yka lr we;s;;a;ajh wju jk fia f.dvk.d.; hq;=h' kj k.rh wkd.;hgTìk f,i yß; k.rhla f,il%udkql+,j mshjfrka mshjrbÈl< hq;= jk w;r ta i|yd ukdk.r ie,eiaula ms<sfh< l, hq;=fjhs' k.rhg wjYH ;rï c,iïm;a ta wi, msysáh hq;= w;r"wdydr ksIamdokh yd n,Yla;sm %Nj k.rh ;=,u fyd a t awdikakfhka imhd .; yelsmßoafoka úh hq;af;a" lsishïjeg,Sul§ Bg Tfrd;a;= fokmßoafoks' th È.= lsÍï yd úYd,lsÍï i|yd wjYH jk ìï we;sfmfoia j,ska iukaú; úh hq;=jk w;r" tys ieu w;g úysfokf,i jq m%jdyk myiqlï mej;shhq;=h' cd;Hka;r .=jka f;dgqm,gm%úIaG ùug lsisÿ ndOdjlafkdmej;sh hq;=h' nyq úO jdis,nd.; yels f,i tjeks k.rhlaf.dv ke.sug fhdað; l%fudamdhmy; oelafjk f,iska úh yelsh'

c, iïmdokh yd wm; c,hc, iïmdokh yd wm; c,hc, iïmdokh yd wm; c,hc, iïmdokh yd wm; c,hc, iïmdokh yd wm; c,hneyer ,Suneyer ,Suneyer ,Suneyer ,Suneyer ,Su

kj k.rhg c,h imhk c,m%Nj k.rh ;=, fyda wdikakfhaúh hq;= w;r c,h wjYH;djhgiß,k f,i mú;%lrKh ù ;sìhhq;=h' kj k.rhg c,h iemfhkc, m%Nj úúOdldrfhka úh hq;=jk w;r jeis c,h iqrelsu jeksúl,am ta i|yd fhdod .; yelsh'wm; c, oyr fjka jYfhkamj;ajd .ekSu" wm; c,h h,s h,spl%ShlrKh lsÍu" N+.; c,re|jqï jeä ÈhqKq lsÍfuysl%fudamdh ie,iqï lsÍfuka.xj;=ro md,kh lsÍu tjeks wx.j,ska iuyfrls'

ikSmdrlaIdjikSmdrlaIdjikSmdrlaIdjikSmdrlaIdjikSmdrlaIdj

fn,dðfhda j.ka;sfhys i|ykamßÈ h,s h,s;a Ndú;d l< yelsjk fia;a" wju f,i c,hNdú;d flfrk wm; c, wmyrkmoaO;s fhdod .eksu;a" fmdaIlmod¾: kd.ßl lDIsl¾udka;hi|yd Ndú;djk mßÈ;a" wmøjHcks; jk ia:dkhg kqÿßka m%fNaofjka lrjk moaO;s Ndú;hgfhduq ùu'

fujks moaO;s j, w;=re M,j,ska n,Yla;s W;amdokhgwjOdkh fhduq lsÍu'

>K wmøjH>K wmøjH>K wmøjH>K wmøjH>K wmøjHbj;,k >K wmøjHiïm;la f,i rel" Bg wd¾Óljákdlula ,nd§u" >KwmøjH ckkh jk ia:dkfhaut ajd j¾. SlrKhiafõÉPdfjka fukauwksjd¾hfhka isÿl, hq;a;ls'ñksia >K wmøjH yd bj;,kldnksl wmøjH tlg mkqjka;=,ska fldïfmdaia lsÍu lrkfldg" fmdfydr t;eku,nd.ekSu isÿl, yels ùu".Dyia:j wdydr ksIamdokh Èß.kajk w;r" bj;,k øjHwE;g neyer lr ùuo md,khlrhs'

n, Yla;shn, Yla;shn, Yla;shn, Yla;shn, Yla;sh

k.rhg wdikakfha n,Yla;sW;amdokd.dr mej;Sfuka yÈisn,Yla;s weK ysàï j,guqyqK §ug wmyiq fkdjkqwe;' fuys§ W;amdokh ydNdú;d l sÍu tlsfklgwdikakfha isÿúh hq;af;a" §¾>jq n,Yla;s ksmehqï cd, j,skaiïfm%aIKh ;=, we;s jkydkslr ;;a; aj j,lajd.ekSugh' idïm%odhs f;,a ydc, úÿ,s n,d.dr mej;sho"úúO úl,am n,Yla;s ksmehqïi|yd k.rh újr úh hq;=h'ksfjia mdol fldg .;a yß;fõ§ n,Yla;s ckkho m%.=kl, hq;= fjhs' .eis *h¾ l%uhgÈhqKq lrk ,o or Wÿka" .EiaWÿka fukau n,Yla;s ksmehqïf,i ie,lsh yels jk w;r"bka ckkh jk iq¿ w¨m%udKh ñksia u, iu.fmdfydrla f,i Ndú;dlsÍug fhdod .; yelsh'iuyr j¾;udk úoHd{hskaf.awkdjels j,g wkqj kj—n,Yla;s hq.fha˜ n,Yla;shb;d wvq ñ,lg ,nd.; yelsjk w;r" idïm%odhsl n,Yla;siemh qï cd, yd mo aO; swNdjhg hEug bv we;'

kd.ßl f.j;= j.d

bv we;s iEu ia:dkhlu

j.djka we;s lsÍfuka k.rhg

m sg; sk a wdydr mdkdÈh

f.kaúu iSud l<yels fjhs'

jeis c,h iqrelsu" .Dyia:

l=Kq lkao,a iïm;la f,i

fmdfydr lrùu" fuu

l%shdjg wkqn,hla jkq we;'

ksfjia Wvq uy,a" jy," jegj,a

iy i|¿;, j.djka i|yd

fhdod.; yel'

ud¾.ud¾.ud¾.ud¾.ud¾.ish¨ m%Odk udj;a kd.ßl n,m%fo aY i Sudfjka tm sgia:dk.; lr hq;= w;r ta isgk.rh fj; msúiqï ud¾.we;súh hq;=h' bÈß ixj¾OkÈhqKq lsßï i|yd m%udKj;abvlv fjkal< hq;= jk w;rweú§u $ Èúu $ hdka;% slixprK" nhsisl,a" frdao u;p,kh" fudag¾ ihsl,a" ;%sfrd ao r:" i sõ frd ao r:hkdÈhg ud¾. ie,iqï úh hq;=w;r" wejis ;ekays§ ud¾. r¿fyda uDÿ úug yelsh' ud¾.ueo yd fl,jr odr iqÿiqfijk .ia j,ska iukaú;hq;=h' ud¾. ie,iqï ck;djgisys,a mßirhl odyh" ;dmhksjd,k jq" jeis c,h fyd¢kanei hk" kd.ßl jk i;=ka,e.=ñ .kakd f,i jq úhuka

11 jeks msgqjg''''

Sri Lanka Engineering News - February 2012IESL NEWS 11

Contd. from page 3....

longitudinal grip and hence, we have to avoid braking.This way, we can maximize the lateral forces thatare vital during cornering. The SLOW IN approachhelps us to do that by making braking unnecessarywhile on the corner.

Secondly, it is advantageous to maintain thedifferences in the weight distribution on tyres withinlimits so that the lateral force differences also wouldbe maintained within safe limits. However, the ideais not to maintain exact equality. Since the tendencyis for the rear tyres to slip out on to the outside ofthe curve, it is of crucial importance to have a goodgrip on the rear tyres. This can be achieved by slightlyaccelerating the vehicle, which as we have seenbefore tends to press down the rear tyres. However,too much acceleration can lead to instability of itsown and therefore, it has to be kept mild.

It is advisable not to resort to accelerating whileturning until you practice it and get the hang of it.Novice drivers should not use it at all. But once youmaster the technique you will feel the added stabilityyourself, which adds to the pleasure of drivingbecause you know that you are in complete controlof what is happening. If you decide to try this, thenensure that you brake more before entering the bend,so that the speed would be low enough, leaving roomfor accelerating while turning.

The transfer of the centripetal forces acting at thepoints of contact of the tyres to the center of massof the vehicle produces couples, which tend to topplethe vehicle to the outside of the curve as shown inFig-3. This effect produces inequalities in weightdistribution. These effects are very clearly seen inFig-3, where the inner rear wheel is completely liftedabove the road, thus loosing its grip altogether.

HIGHWAY DRIVING....

Contd. from page 5...

Any reasonable person wouldagree that the first solution is muchbetter than the second. In fact thesecond may be considered as a“Leda Marunath Bada SuddaVuna” (Although the patient diedhis stomach was well and trulypurged) type of solution.

In the second solution we havekil led the equation and whatremains is an inequality. It is truethat the inequality is true. But ifyou read the text of the puzzle,what I wanted is for you to correctthe equation. Not to destroy it. Theend result should be a correctequation – not a correct ‘non-equation’.

Let us say someone gives his petdog for you to correct its badhabits like wetting the floor. Howwould he feel if you solve theproblem by simply killing the dog?True, it is a highly effective solutionthat guarantees the total absenceof canine urine on the floor, but Idon’t think the owner would beamused by it. It would be ratherlike a Mahadenamutta typesolution.

Many readers went for thissolution because it was theeasiest thing to do. It would bemuch more convenient and muchless time consuming to kill the dograther than spend months tryingto house train it – provided you

can get away with it and get yourtraining fee too.

What happened in this case wasthat many saw this solution andwent towards it. What they didnot see is the trap door in its path.They simply fell down it.

In real life problem solving too, itis very easy for even the mostintelligent to fall in to such traps.We have to know that suchtemptations can lead todisasters. When you happen tohit upon any solution askyourself these questions:

• Does it fit all the evidence/conditions?

• Are their any other solutionsthat you have missed or ignored?

• Is it the best solution?

It is my experience that, whenyou hit upon the best solution,you will immediately know,because you get that uniquefeeling.

Prize Winner: Judging from thenumber of responses received,this has turned out to be the mostpopular puzzle published in thePuzzle Corner. This month’s prizegoes to Student Member R.Anojhkumaran as the youngestamong them. The other readerswho sent in correct solutionsare:

1.I. D. Chaminda Indrajith

2.N. S. Wettasinghe

3.Anuradha Udunuwara

Solution for Puzzle No. 42...4.Chintaka Kandapahala

5.K. P. Wathuge

6.P. A. R. B. Ponnamperuma

7.Dhanushka I. Wikramasinghe

8. N. K. Kumarage

9.Kayananthy Piraveenan

10.A. C. K. Bandara

11.K Navarathnarajah

12.E.A.D.M. Amithodhana

13. Thurairajah Rajeeve

14.L.H.Fernando

15.Shubhani K A S.

Due to the large number of e-mails received, it is possible thatI may have missed some of thenames of those who sentcorrect solutions. If so, pleasewrite to me and I will makeamends in the next issue.

Another unique feature about thepuzzle is that almost all theyoung members got it right, whilemost of the older members wentastray. I have a nice theoryabout it too, which has to awaitanother opportunity for publication.

Out of the senior members whogot it right, we have EngL.H.Fernando as the most seniormember. Congratulations EngFernando! I wish we could haveawarded you a special prize.

Happy Puzzling to All!!!

Puzzle Guru SarathChandrasiri

l%uhla fjhs ' fojk f,d alh qo aOfhka mi q " ckdêm;swhsfIkaydj¾f.a Wmfoia u;"weußld tlai;a ckmofha ish¨m%Odk udj;a yÈis wjia:djl§ .=jkahdkhla f.dvneiai úh yels whqßkaÈ.= iy mq¨,a lrk ,§'

.ukd.ukh.ukd.ukh.ukd.ukh.ukd.ukh.ukd.ukh

.ukd.ukh yev .eish hq;af;a tai|yd wju ld,hla jeh jkf,ih' tys§ nia" jeka" ÿïßh iyÈh oyr hk ish,a, Ndú;d l<hq;= jk w;r" th .=jka .uka iu.otaldnoaO úh hq;=h' oekg mj;akdjeõ" l=vd .=jka hdk i|ydiajdNdúl .=jka m: f,i Ndú;dl< yelsh'

ksjdi yd f.dvke.s,sksjdi yd f.dvke.s,sksjdi yd f.dvke.s,sksjdi yd f.dvke.s,sksjdi yd f.dvke.s,s

;Ügq y;rla olajd Wia f.dvke.s,skj w.k.rh ;=, bÈlsÍug Wkkaÿl< hq;=h' ;ks ;Ügqfõ ksfjiabÈlsÍfuka neyer úu WÑ;h'mdi,a" wdfrda.HYd,d" fi,a,ïmsÜgks" iqmsß fjf<| ie,a ydld¾hd, yel s bl auksk a ydmyiqfjka .uka l< yels ÿr m%udkj,ska msysgqúh hq;=h' fuu há;,myiqlï bÈúh hq;af;a iq¾h Yla;shyd iq<x n,h Wmßu jYfhkam%fhdackhg .; yels mßoafoka ydyels;dla ÿrg fudaiï jeisj,wys;lr n,mEï wju jk mßoafoks'oekg Ndú;d lrk yß;f.dvke.s,s m%jk;djh tfiaumj;ajd f.k" wkd.;fha§;jÿrg;a j¾Okh lrúh hq;=h'

Y%S ,xld ck.ykh >k;ajh w;skaf,dalfha 15ia jk ia:dkh mukysñ rghs' ^idudkHh o, jYfhkaj¾. lsf,dañgrhlg mqoa.,hka 290ls'& fld<U Èia;%slalh 3305&" .ïmy^1541& " iy l¿;r ^673&ixikaokd;aulj uq,;sõ Èia;%slalh^50&" fudKrd., 72&" jjqkshdj^81&iy ls,sfkdÉÑh ^106&' fuuúIuldÍ ck.yk >k;aj rgdjw;sYhskau fld<U flakaø lr.;aixj¾Ok l%shdodufhys úmß;;;a;ajhla jk w;r" th rgliunr yd iu;=,s; ÈhqkqjgndOdjls' fï ;=,ska mek ke.S we;swiu;=, s; yd wiykldÍjd;djrkh iajdNdúlj l%ufhkafjkia lsÍug rel=,a fok f,iw.kqjr ia:dk.; l< hq;=fjhs' fïwkqj h,s;a jrla úh<s l,dmhckdlS¾K m %fo aYhla njgm;alsÍfï iajdNdúl yd fmr,sldrhdka;%khla wjYH fjhs'

Y%S ,xldfõ Widúj, jeämqruúNd. jkqfha bvï wdrjq,a yd ine¢kvq yn nj fndfyda fofklafkdokS' bvïj, whs;sh yd tajdfhameje;au ms<sn|j wdrjq,a jHdêhlajk ;rugu ms<s, ú we;s nj fuhskafmfka ' l,lg by;fko¾,ka;fha mej;sfhao ,xldfõfukau ;;a;ajhls' tys ck.ykj¾Okh ngysfrka jq uqyqÿ nvm%foaYj, oelsh yels jkq w;rwksl=;a k.rj, t;rï ckdjdifkdúh' fuh y÷kd.;a miq 1950 §fuu m%jk;djh h,s fjkia lsÍugkef.kysr m %fo aYfhy sfj.fk.ayka kqjr úYaj úoHd,k.rhla bÈlf<a wjeis ish¨há;, myiqlï iu.h'

wmf.a j¾;udk w. k.rhfjk;lg fhduq lrkafka kï"jvd;a f.dapr jk ia:dk ljrlaúh hq;=o' fld<U$ Y%S chj¾Okmqrh;j;a fndfyda ld,hla wd¾Óln,h ysñ k.rh f,i jecfUkakgbvlv we;s ksid kj w. k.rhbka b;d wE;l msysgk tlla úhhq;=h' tu w.k.rh fld<U yd Y%Schj¾Okmqrh yd ine¢ ish¿W!k;djkaf.ka úks¾uQ¾; jQ" 21jk ishjig f.dapr" yd tyswNsfhda.hkag uqyqK Èhyels

10 jeks msgqfjka''''

w. k.rh'''''w. k.rh'''''w. k.rh'''''w. k.rh'''''w. k.rh'''''

k.rhla úh hq;=h'

wkqrdOmqrh jir 1000 la mqrdY% S ,xldfõ wLkavj mej;sid¾:l yd ufyaYdlH w.kqjrhs'fgd,ñf.a is;shu wkqj l%sia;=j¾I f;jeks ishji jk úg;ath Y % S ,xldfõ n,flak aøi a:dkj mej;=k s 'wkqrdOmqr k.rh m%Odk jeõ;=klsk a yd l =vd jeõ.Kkdjlska iukaú;h' thf,d al Wreuhla f,ihqfkiaflda ixúOdkh úiska kïfldg we;' wkqrdOmqr kjk.rh úêu;a f,i ie,iqïlrbÈlr we;s w;r tys jeä ÈhqKqlsÍï yd È.= lsÍï i|ydo wjldY;nd we;' th uqyqÿ uÜgfukaógr 78 la Wiska msysáhls'

Y%S ,xldfõ w;S; Y%S úN+;sh h,sm%;sia:dmkh msKsi óg;a jvdfjk;a kqjrla fõ oehs hkakm%Yakhls' úêu;a ie,eiaulgwkqj 21 fjks ishjig Tìkf,i há;, myiqlï we;sw.kqjrla merKs iy kj k.rhjgd f.dvke.sh yels f,ioekgu;a wkqrdOmqr k.rh yev.iajd we;'

wkqrdOmqr w.kqjr jqjfyd;afuf;la wm rgg jo ÿkafndfyda m%Yak l%ufhka myjhEug bv we;' udkal=,ï k.rhW;=f¾ mßmd,k flakaøia:dkhf,i kï lr ; sîfuka "wkqrdOmqrhg jkaksfha yo .eiaufyd¢ka oefkkakg .kq we;'úfoaYslhskag ,xldfõ w;S; Y%SúN+;sh fukau jdKsc lghq;= ydúfkdao ùu tla jru isÿlr .;yelsh' fuh n,h úuOH.; lsßujvd;a ÑriaÓ;j mj;ajd .ekSui|yd fhdod .; yels WmdhYS,Sie,iquls'

fmr mdif,a isg úYaj úoHd,holajd fkdñf,a wOHdmkh,ndfok wm jeks rgj," kjw.kqjrla ìyslrKq jia" bÈlsÍïj,g wksjd¾h fiajfha fh§u u.skawOHdmkhg fhdokq ,nkwdfhdackfha úmq, M, fk,d.;yels jkjd mukla fkdj" th B<.mrïmrdjg fokq ,nkmq¾jdo¾Ykhlao l< yels fjhs'fuu.ska foaYfhys jev lrkck;djf.a Y%udNsudkh by,;,hl ;nkq w;r" oekg mj;skks,a yd iqÿ lrjg lñi orKrelshdj, we;s lD;%su fjkfiys jeglfvd¨ ì| oud" tu mr;rh fnd|lrjkq we;' fuf,i w.k.rhwkqrmqrhg f.kheug jvd;af.dapr l%uh jkqfha rch ydúmlaIh w;r ta ms<sn| tl.;ajhlawe;slr .ekSuhs' túg foaYmd,kndOd j,ska f;drj" tl. jk ld,igyklg wkqj" wod, há;,myiqlï bÈlr" wkd.; yß;w.kqjr f.dv k.d.; yelsh'

fujeks uyre iy w¾:dkaú;m %úY aGhlg t<ôh yel afl awkd.; oelaula m s< sn| ukdmßphlska oEia újr lr .; yels"oeä wêIaGdk Yla;shlska fyìm qo a.,h sk af.ka iukaú;kdhl;ajhlg muKs' N+f.da,ShjYfhka úúO ia:dkj, msysáYla;su;a wd¾Ól uOHia:dk msßjrd"jvd;a wdrlaIs; jk mßÈ" m%n,foaYmd,k flakaøia:dkhla kjw.kqjr f,i W;amdokh lr.eksu" iuia: Èjhsfkys ydiuqødikak ÿm;aj, iu;=,s;ixj¾Okhla u; = mrïmrd.Kklg ,ndfokakls'

fï i|yd lÓldjla f.dvke.sugfuh iqÿiqu ld,hhs'

igyk - fuh Ceylon DailyNews m;%fha 20$07$2010 Èk m<jQ,smshl mßj¾;lhls'

mßj¾;l" jr,; a bxðfkaremßj¾;l" jr,; a bxðfkaremßj¾;l" jr,; a bxðfkaremßj¾;l" jr,; a bxðfkaremßj¾;l" jr,; a bxðfkarefldals, rKisxyfldals, rKisxyfldals, rKisxyfldals, rKisxyfldals, rKisxy

How can we say that it is inadmissible. What is the litmus test for the admissibility or non admissibility ofa solution within the rules of this puzzle? I said that changing the voice is a way of communication andhence it is not admissible. But if you go deep in to it, even in the official solution the answers of thecompetitors communicate some additional info. which the next competitor can use. In fact without suchinfo you cannot improve the chances of winning and there is no substance in the puzzle.

Therefore, I developed this test for checking the validity of the method. The judge goes to each competitorand he whispers his answer so that only the judge can hear it. Then the judge immediately repeats theanswer loudly for the others to hear.

This way methods such as voice changes will have no effect. But any methodology that improves thelogic value will pass through the test. If your method still works, it is admissible. May be you can improveyour team’s chances now.

Contd. from page 5.... MORE ON PUZZLES 41 & 46....

Contd. from page 1...

base having a CBR (California BearingRatio) of more than 20 had to be used.According to the pavement design thathad been carried out he has laid the basecourse to a thickness of 200mm.

Once the formation of the road was done,he had used a prime coat supplementedby DBST (Double Bitumen SurfaceTreatment). Therefore, existing materialfrom the area has been used for thisproject, which would otherwise have costa large sum of money to import materialfrom distant places which may be morethan 100 km away. The Presidentcongratulated this young engineer whohad used an innovative method torehabilitate this stretch of road. However,Eng. Sivakumar was humble enough tostate that the instructions to carry out sucha method had been given by the Chairmanand the Director General of the Roadsand Traffic Authority.

Therefore, the President believes thatthese types of experiences should beassimilated among our fellow engineersas an exercise to widen their knowledgein the field of engineering. As Eng.Sivakumar had been very busy as theTeam Leader of some other similar project,the President took upon himself to writethis note to SLEN. At the same time thePresident is also inviting those who havefirst hand experiences such as these towrite to SLEN about what they do in theirprovinces so that engineers can learnfrom the experience gained by theirbrothers and sisters in the profession.

PLEASE SHARE....

Sri Lanka Engineering News - February 2012IESL NEWS12

Printed by Karunaratne & Sons (Pvt) Ltd., No. 67, UDA Industrial Estate, Katuwana Road, Homagama