Engineer : Journal of the Institution of Engineers, Sri Lanka
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Open Access journal
ISSN (Print) 1800-1122
Published by Sri Lanka Journals Online [46 journals]
- Review Usability of Facilities for Visually Impaired People in Sri Lanka
Case Study of Bambalapitiya- Kollupitiya Section
Abstract: Accessibility protects the basic rights of a human being such as the right to receive facilities like healthcare, education and the right to do an occupation to earn one’s living etc. Therefore it is essential to develop a barrier free road environment that guarantees accessibility for all. Accessibility for differently abled people is not a new concept to the world. There are many related codes and practices in other countries. Sri Lanka has recently introduced this concept to the road infrastructure by improving the Bambalapitiya – Kollupitiya road section as disabled friendly.
The study team has reviewed international guidelines on designing facilities for blind and visually impaired people. The study team has also observed the behaviour of two trained blind personal while they were utilizing the tactile guide way at Bambalapitiya – Kollupitiya road section. A video clip was produced to further analyze their behaviour and review the usability of the facility. Several problems have been identified in the new facility. Most importantly when compared with guidelines which have been followed , there were deviations of construction due to faulty workmanship and lack of details mentioned in the document. Comments of two people were noted regarding their personal experience and their suggestions for further improvements.
It was found that the guidelines  have been prepared neither with proper understanding of visually impaired people nor the suitability of the design for the road environment in our country. After considering all these facts, the study team was able to modify some guidelines and even come up with new standards for the Sri Lankan condition. The study team has proposed new layouts for pedestrian walkways and bus stops considering the needs of both visually impaired and mobility impaired people.
ENGINEER, Vol. 47, No. 02, pp. 33-45, 2014 Published on 2015-11-12 00:00:00
- Earthquake Performance of free Standing four Legged Greenfield Towers
Abstract: Telecommunication/broadcasting towers play a vital role in telecommunication and broadcasting sectors by facilitating wireless data and signal transmissions. The failure of a tower especially under a disaster situation such as earthquake is a major concern mainly in two ways. One is the failure of communication/broadcasting facilities which will become a major setback to carry out rescue and other essential operations during a disaster while failure of a tower will itself cause a considerable economic loss as well as damages to human life since these are tall giant structures in most of the cases.Presently, a strong dialogue is going on amongst the professionals regarding the seismic condition of our country with the reported earth tremors in recent times. Hence, evaluating the structural performance of existing telecommunication/ broadcasting towers under seismic loads is utmost important since almost all existing towers have not been designed considering seismic forces due to traditional belief that Sri Lanka will not be subjected to earthquakes of appreciable magnitudes.Considering the above situation, assessment of structural performance of existing towers (which were not initially designed considering earthquake loading) under possible earthquake loading with different analytical techniques was selected as main objective of this study. Accordingly, behaviour of existing four legged Greenfield towers under seismic loading using ANSI/TIA-222-G tower design code was studied and results, observations and conclusions based on this analysis are presented.
ENGINEER, Vol. 47, No. 02, pp. 85-95, 2014 Published on 2015-11-12 00:00:00
- Arsenite Removal from Drinking Water using Naturally available Laterite in
Abstract: Arsenite, As(III) is the most soluble form of arsenic species. Arsenic removal efficiency by laterite (commonly found in Sri Lanka) was examined as a function of pH, initial arsenite concentration, laterite dosage, contact time and mixing rate. More than 90% arsenite removal could be achieved within 5 minutes when pH is around 10. By treating the water at this pH range, the current USEPA standard for arsenic in drinking water (10 ppb) can be maintained when the arsenite / laterite ratio is less than 10(µg/g). Results of the study showed that naturally available laterite in Sri Lanka can be used as an effective adsorbent to treat arsenic contaminated water.
ENGINEER, Vol. 47, No. 02, pp. 23-31, 2014 Published on 2015-11-12 00:00:00
- Profile of the Sri Lankan Electrical Engineering Industry
Abstract: The electrical and electronic industry in Sri Lanka, although relatively small in itself, is a key service industry to other industrial sectors as well. In the study presented, a sample of around 300 companies/industries has been the surveyed from around 500 identified companies to obtain the profile of the electrical engineering industry. From the surveyed companies, more than 76.8% are in the electrical industry and these companies account for over 81.1% of the total employment provided. The energy supply sub sector provided 36.7% of the total employment, and is influenced heavily by the large workforce of the CEB. The electrical services industry, which is mostly dominated by the small enterprises, contributes to 20.9%, while electrical products sector accounts for 23.5% of the employment.
The majority of the industry’s employment is concentrated in the operational grades (75.8%) where the technical skills requirements are quite specific for a particular role and quite diverse for different roles. The skills requirement becomes more generalized, with more emphasis for managerial qualifications, as one goes higher up in the occupational structure.
At the operational levels, the vast majority of the workers are with either GCE O/L or A/L qualifications (65.2%). On the other hand, higher education qualifications are much more sought after at the managerial level and decision making level with 72.2% of the managers and 88.8% of the decision makers possessing a degree or above qualifications.
The growth potential of the electrical and electronic industry has been estimated, based on census and statistics of GDP growth rates of similar industries, by categorising the industry into five sub-sectors, namely energy supply, electrical products, electrical services, export oriented electronics, and local consumer electronics and services. The forecasted annual growth of employment for the industry is 14.4% (Electrical industry 13.7% and electronics industry 16.8%).
ENGINEER, Vol. 47, No.02, pp. 9-21 2014 Published on 2015-11-12 00:00:00
- Experimental Investigation of Sediment Trap Efficiency in Reservoirs
Abstract: Reservoir sedimentation has become one of the major problems facing water resources development projects in many countries around the world. However, only a limited number of studies has been reported in this field, particularly addressing the trap efficiency of reservoirs. In addition, whatever available studies in this area also consider few parameters governing the reservoir sedimentation. As a result, the available knowledge on trap efficiency is not very well defined. Brune curve  has been widely used for estimating trap efficiency of reservoirs at present, but it has several limitations, as it considers only the reservoir capacity and inflow ratio for estimating trap efficiency. The objective of this study is to formulate an improved methodology in estimating reservoir sedimentation through laboratory experiments. A small-scaled laboratory model was set-up in representing a reservoir and a series of tests were conducted by varying inflow rate, inflow sediment concentration, reservoir capacity and outflow rate. The experimental results were compared with the available theories and found that they are not very much in agreement with many of the existing theories which are mostly based on limited number of parameters. A comprehensive data analysis was performed using dimensional analysis to develop an improved relationship to estimate reservoir sedimentation incorporating many parameters governing the problem. However, the applicability of the proposed method is still limited only to the reservoirs with continuous spilling condition. In addition, only one type of sediment gradation (d50) was used in the experimental runs and thus, the effect of sediment sizes is not well represented in this method. However, the relationship developed in this study could be further improved by conducting more experimental runs by varying few other parameters which are not considered in the present study.
ENGINEER, Vol. 47, No.02, pp. 1-8 2014 Published on 2015-11-12 00:00:00
- FROM THE EDITOR Vol. 47(2)
Abstract: ENGINEER, Vol. 47, No. 02, pp. III, 2014 Published on 2015-11-12 00:00:00
- Prediction of Atmospheric Corrosion –A Review
Abstract: Corrosion is defined as the degradation or loss of function of materials due to environmental effects. Corrosion has a huge impact on the economy of a country. This depends on the corrosive nature of environment of the country. Financial loss due to corrosion is inevitable but is controllable with the aid of proper corrosion management systems. Most of the countries use different methods for implementing corrosion management system in order to minimize the corrosion loss. In Sri Lanka the concern about corrosion is at a minimal stage but having a corrosion management system is becoming an essential requirement for future Sri Lanka. Implementation of corrosion management system has to be an all-country effort which has to be done with a much careful assessment of corrosive environment. There are several approaches for the assessment of corrosive environment and many researchers have been conducted all over the world. Evaluation of corrosivity as a function of environmental variables, which is known as corrosion modeling, and classification of corrosivity of atmosphere are widely used methods to assess the corrosive environment. In this paper the authors discuss about several existing environmental evaluation methods and models.
ENGINEER, Vol. 47, No. 02, pp. 75-83, 2014 Published on 2015-11-12 00:00:00
- Reviewing of Insulator Selection Criteria for Overhead Power Lines in
Coastal Areas of Sri Lanka
Abstract: At present porcelain and glass insulators are used for overhead power lines in Sri Lanka. Salt contamination on insulators of coastal lines assists leakage currents to passing over the insulator surface and cause insulator flashing over. Frequent power outages due to flashing over of insulators on overhead power lines are common in coastal areas and it reduces the reliability of the power system considerably. It has been observed that this problem is very severe in costal lines in dry zone of Sri Lanka especially in Puttalam, Mannar and Jaffna areas. Partial blackout caused by flashing over of insulators on 220kV transmission line running closer to the sea and across the Kalpitiya lagoon from Norochcholai coal plant to Veyangoda switching station shows the severity of this problem. Therefore it is timely requirement to review the insulator selection criteria for overhead power lines to find out mitigation measures against the flashing over of insulators due to marine pollution. This paper describes the mechanism of flashing over of insulators due to marine pollution and highlights the limitations of the presently following electrical standards for insulator selection based on field measurements and maintenance experience. It is emphasized that the most successful method that can be employed to determine the ideal insulator out of insulators made of different materials and of different shapes is to verify their performance by conducting long term field measurements at the exact environment. Apart from that the existing practices applied on distribution network to minimize insulator flashing over is evaluated technically and financially in order to identify the best solution. Application of new technology such as adaptation of polymeric insulators, insulator coating materials and applicable online insulator washing techniques are also investigated. The importance of type test reports named as artificial pollution tests to understand the pollution immunity of insulators is also discussed. The value of establishing insulator field testing stations in problematic areas is strongly recommended and the test techniques applicable in field evaluation of insulator performance are briefly explained.
ENGINEER, Vol. 47, No. 02, pp. 57-73, 2014 Published on 2015-11-12 00:00:00
- Usability of Public Transport for Differently abled People in Sri Lanka
Abstract: As a developing country, public transport is a vital part of the National transport system. In Sri Lanka, Buses, Trains, Vans, and Three wheelers are widely used as public transport modes. Even though Sri Lanka has almost adequate numbers of fleet in each public transport modes, they do not have sufficient facilities for differently abled people. It has been found that number of differently abled people has increased significantly due to the civil war which was ended in 2009. The differently abled people are the people who have only certain limitation on their activities. It was found that majority of them are not employed and depend on their families for survival. So the public transport system should be accessible, usable and safe for differently abled people to join them for the economic development of Sri Lanka. There should be well developed specifications such as TRL Overseas Road Note 21 and DPTAC manual for public transport modes to accommodate differently abled people. In Sri Lanka, the Gazette of Democratic Socialist Republic of Sri Lanka No 1,467/15 dated on 17/10/2006  is the only one available, but, it does not have much detailed specifications. Therefore, the need of a new specification has been emphasized in this study. The problems in public transport modes in serving differently abled people of Sri Lanka were gathered through a questionnaire survey by mail. Response of three types of disabilities; visually, hearing and physical impaired were analyzed in the study to understand the accessibility issue of differently abled people. Detailed survey of public transport facilities was conducted to identify the suitability of available transport modes for differently abled people. Survey on the existing transport modes showed that most of the vehicles that are used in public transport do not have adequate facilities for the differently abled people.
ENGINEER, Vol. 47, No. 02, pp. 47-55, 2014 Published on 2015-11-12 00:00:00
- Automated Dynamic and Cooperative Base Station Range Setting in CDMA2000
Abstract: Cell shrinking is a common phenomenon in code division multiple access systems in which the cell service area reduces with the loading of the cell. To minimize the service outages resulting from cell shrinking, an automated dynamic and cooperative base station range setting scheme for the CDMA2000 system is proposed. This range setting software resides in a dedicated computer coupled to the back administration module server at the base station controller, periodically checks the traffic reports generated and identifies the loading of cell sectors which in turn initiates the generation of a dynamic range setting script. Automatic execution of the script adjusts the ranges of the neighbouring cell sectors such that the subscribers with high probability of dropping from the loaded sectors due to cell shrinking are now smoothly transferred to their neighbours. This system overcomes most of the practical issues that arise in human controlled manual range changing systems which are currently deployed in Sri Lanka.
ENGINEER, Vol. 47, No. 01, pp. 1-8, 2014 Published on 2015-11-02 00:00:00