Engineer-Journal of the Institution of Engineers Sri Lanka最新文献

{"title":"Preliminary Investigation of the Suitability of Coir Fibre and Thermoplastic Waste as a Construction Material","authors":"P. D. Dharmaratne, R. A. Jayasinhge, A. Nilmini, G. Galabada, R. Halwatura","doi":"10.4038/engineer.v54i4.7471","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7471","url":null,"abstract":": Waste polyethylene creates serious environmental and social problems in Sri Lanka. The amount of waste polyethylene increases daily, further aggravating environmental and social issues. Finding out the most suitable solution for this is a vital requirement. This research focuses on investigating the possibilities to convert this waste polyethylene as a sustainable construction material by combining it with readily available coconut fibre. A preliminary investigation was carried out on thermoplastic/coconut fiber composites to evaluate their suitability in the construction industry. Composite sheets, 2.5 mm and 3.2 mm thick, were developed by varying coir fibre weight with a suitable polymer matrix using a hot press machine. In this step, mechanical properties of the composite material were measured through tensile and bending tests. The tests were carried out complying with ASTM D3039 and ASTM D790, respectively. The surface morphology of coir fiber and the fractured surface of failure material were investigated through Scanning Electron Microscopy (SEM). Maximum tensile strength was observed as 6.75 N/mm 2 when the coir wt. fraction is in-between 20-30% by total weight. The maximum bending strength was 29.85 N/mm 2 when the coir fraction is almost 25% by total weight. The corresponding mechanical properties are compared with the available materials in the industry.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"6 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86808721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity Analysis of Brinell Hardness Number to Material Properties of Structural Steel: A Numerical Study","authors":"S. P. L. Madhumali, J. Jayasinghe, C. Bandara, A. Dammika","doi":"10.4038/engineer.v54i4.7472","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7472","url":null,"abstract":"Hardness is not a fundamental property of a material but it is related to the elastic and plastic properties of the material. Hardness of a material can be determined from indentation hardness tests. Brinell hardness test is one of the commonly used macro-indentation hardness test types to quantify the hardness of a material. In this study, the sensitivity of Brinell Hardness Number (BHN) to the material properties of structural steels that exhibit a plastic plateau in their true stress-strain curve is analysed. Four basic structural steel material properties, Young’s modulus (EE), yield strength (σσyy), ratio (αα) between the strain at beginning-point of strain hardening (εεssss) and the yield strain (εεyy) and strain hardening exponent (nn) are considered for the sensitivity analysis. By identifying the sensitivity of hardness to these material properties, an inverse analysis method based on a hardness test can be developed to identify the unknown steel materials. For a given material combination, the loaddisplacement curve of macro-indentation can be developed using the Finite Element (FE) simulation. For that, a 2D axisymmetric nonlinear FE model is developed using finite element software package ABAQUS and validated using past experimental data. Then BHNs are calculated for selected material combinations and variation of BHN with each material property is obtained. Considering the relationships between material properties and BHN, the sensitivity of BHN to each material property is calculated. Finally, a comparison is made for the sensitivity of hardness by considering all four material properties.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"88 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79763123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictive and Standalone Fault Diagnosis System for Induction Motors","authors":"H. Jayasinghe, I. G. Ahangama, V. D. V. Y. Dharmasiri, D. C. G. Nisansala, J. Karunadasa","doi":"10.4038/engineer.v54i4.7466","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7466","url":null,"abstract":"Sudden faults created in induction motors result in catastrophic failures and loss of production. Therefore, the industry is in need of a predictive based system that can identify developing faults in advance. Condition monitoring is used as the general method of identifying faults and taking measures before the dreadful situation. However, there is limited work done on the predictive methodologies based on the trend analysis. The study presented in this paper proposes a novel method that identifies trend variation of critical harmonics of the vibration spectrum with increasing fault severity for frequent mechanical faults; structural looseness, misalignment, bearing eccentricity and bearing inner race fault. Faults were artificially induced on a three-phase induction motor and vibration data obtained was analysed with a MATLAB based algorithm.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"7 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84979710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multi-Modular Approach for Sign Language and Speech Recognition for Deaf-Mute People","authors":"D. Dahanayaka, B. Madhusanka, I. U. Atthanayake","doi":"10.4038/engineer.v54i4.7474","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7474","url":null,"abstract":"Deaf and Mute people cannot communicate efficiently to express their feelings to ordinary people. The common method these people use for communication is the sign language. But these sign languages are not very familiar to ordinary people. Therefore, effective communication between deaf and mute people and ordinary people is seriously affected. This paper presents the development of an Android mobile application to translate sign language into speech-language for ordinary people, and speech into text for deaf and mute people using Convolution Neural Network (CNN). The study focuses on vision-based Sign Language Recognition (SLR) and Automatic Speech Recognition (ASR) mobile application. The main challenging tasks were audio classification and image classification. Therefore, CNN was used to train audio clips and images. Mel-frequency Cepstral Coefficient (MFCC) approach was used for ASR. The mobile application was developed by Python programming and Android Studio. After developing the application, testing was done for letters A and C, and these letters were identified with 95% accuracy.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"12 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81833109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysing Pedestrian Safety in School Zones Based on Behaviour Risk","authors":"T. Dias, D. K. Wickramarachchi","doi":"10.4038/engineer.v54i4.7468","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7468","url":null,"abstract":"","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"26 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87934291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a Biomass Micro Gasifier Cookstove by CFD Modelling","authors":"Daham Liyanage, G. Senavirathna, Chamini Rodrigo, Pujitha Thennnakoon, Pradeep Madawala, K. Dassanayake","doi":"10.4038/engineer.v54i4.7467","DOIUrl":"https://doi.org/10.4038/engineer.v54i4.7467","url":null,"abstract":"","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"4 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74895483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of Supply Chain Risk Factors of the Large- Scale Apparel Manufacturing Companies – Sri Lanka","authors":"P. Sugathadasa, S. W. Senadheera, A. Thibbotuwawa","doi":"10.4038/engineer.v54i3.7459","DOIUrl":"https://doi.org/10.4038/engineer.v54i3.7459","url":null,"abstract":"","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"377 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77951024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Climate Elasticity of Runoff based on Observed Rainfall, Streamflow and Simulated Future Streamflow using SWAT Model in Kelani Ganga Basin","authors":"K. Siriwardena, R. Rajapakse","doi":"10.4038/engineer.v54i3.7455","DOIUrl":"https://doi.org/10.4038/engineer.v54i3.7455","url":null,"abstract":": Kelani Ganga basin is the 7 th largest watershed in Sri Lanka, spanning over 2,292 km 2 and annually discharging 4,225 MCM flow to the sea. The basin currently hosts over 19% of the country’s population and is the primary source of drinking water to over 4 million people living in Greater Colombo. Hence, the present study was undertaken to evaluate the Climate Elasticity of Runoff based on observed rainfall, streamflow data and simulated future streamflow using the SWAT Model in the Kelani Ganga basin, targeting sustainable management of basin water resources in future. The runoff elasticity ( ε ) is assessed by two methods for the present and 2040 scenarios. The selected three hydrometric gauging stations exhibit significant downward trends for the period of 1980 to 2016. An 80% of the rain gauges in the middle and upper basin show significant decreasing trends for high to low rainfall totals for Yala season as per Innovative Trend Analysis (ITA) for the period of 1980 to 2016. Mass balance performance error ( Er ), Nash–Sutcliffe Efficiency ( NSE ) and Coefficient of determination ( R 2 ) are used as multi-objective functions and 8.90%, 0.65, 0.72 and 9.10%, 0.69, 0.69 are obtained for the above objective functions in SWAT model for the calibration and validation periods of 1970 to 1980 and 1982 to 1992, respectively. A 1 ⁰ C of temperature increase causes a 6.9% and 7.4% runoff decrease for the current scenario and it causes 0.4% increase and 1.5% decrease of runoff for Future Pessimistic Climate change Scenario as evaluated by the methods proposed by Zheng et al. [24] and Sankarasubramanian et al. [22], respectively. A 1% of rainfall increase causes a runoff increase of 0.002% and 0.370% for the current scenario and a runoff increase of 0.005% and 0.360% for 2040 as evaluated by the two methods, respectively. It is recommended to further analyse the water allocation model for better results with practical implementations by considering the identified trend after 1995 in future research for better planning and management of water resources in future.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"41 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84133475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study on Knowledge, Skills and Abilities of Labourers Affecting the Performance of Building Construction Projects in Sri Lanka","authors":"M. Kesavan, P. Dissanayake, C. Pathirana, M. Deegahawature, K. D. Silva","doi":"10.4038/engineer.v54i3.7456","DOIUrl":"https://doi.org/10.4038/engineer.v54i3.7456","url":null,"abstract":": The successful completion of a construction project highly depends on the labour efforts and performance. In developing countries like Sri Lanka, the most important challenge faced by the construction industry is the low performance of labour operations. Sources reveal that the knowledge, skills and abilities (KSAs) of labourers significantly affect the performance of labour in the construction projects. This study is aimed to identify the critical KSAs of labourers which highly influence the performance of building construction projects in Sri Lanka. The significant KSAs of labourers were initially identified using qualitative thematic analysis method through a comprehensive literature review and a series of structured interviews conducted among construction experts in Sri Lanka. Using the snowball sampling method, a questionnaire survey was carried out among building construction projects in Sri Lanka to measure the severities of these KSAs on the performance of construction. A total of 154 contractors responded to this survey. The severities of the KSAs were measured by calculating their Relative Importance Index (RII) values. Overall, 13 knowledge areas and 28 skills/abilities of labourers were identified as critical based on their RII values. The results show that the industry should have more focus on improving the work-related cognitive and self-management skills of the labourers than their transferable and technical skills. The validity and reliability of the findings were ensured using relevant statistical tests. There were no significant differences found between the perceptions of the different levels of working categories on the identified KSAs. It is highly recommended to consider the critical KSAs identified in this study, when current practices are upgraded for construction labour force in the industry. The findings of this study are expected to be very useful to the Sri Lankan construction industry as well as other developing construction industries in similar scenarios.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"36 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75519034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of Experimental Hysteresis Loops Under Non-Proportional Loading","authors":"T. M. D. N. Medagedara","doi":"10.4038/engineer.v54i3.7457","DOIUrl":"https://doi.org/10.4038/engineer.v54i3.7457","url":null,"abstract":"Fatigue life prediction is a challenge for engineers when it comes under nonproportional loading. In many applications, engineering components are subjected to complicated states of stress and strain. Studying of hysteresis behavior under non proportional loading is important for reliable engineering designing for studying the cyclic deformation that is essential to find the plastic strain ranges which is used for fatigue life prediction. This paper discusses the behavior of the hysteresis loops created experimentally under various non-proportional loadings. EN8 carbon steel notched specimen was used for the experimental analysis. The tests were carried out using a multi axial test machine However, the results have shown significant difference in hysteresis behavior changing the path of non-proportional loading. Comparing the experimental results of direct and shear strains of non-proportional loading paths, some loading cycles are more damaging in terms of fatigue life.","PeriodicalId":42812,"journal":{"name":"Engineer-Journal of the Institution of Engineers Sri Lanka","volume":"114 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73308349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}