Faculty of Engineering
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Publication Open Access Implementation of water–saving agro technologies and irrigation methods in agriculture of Uzbekistan on a large scale as an urgent Issue(Springer Science and Business Media Deutschland GmbH, 2022-10) Rathnayake, U; Chathuranika, I; Khaniya, B; Neupane, K; Rustamjonovich, K. MUsable water resource is limited, even though 71% of world is covered by water. Therefore, enough conficts to the usable water can be found throughout the world. Usable water for irrigation is a top priority, probably it would be seconding only to the drink water supply. However, prioritizing one usage over another is challenging to many stakeholders. Therefore, sustainable water usage is essential to avoid any conficts among the stakeholders; nevertheless, highly challenging in the developing world. Therefore, this paper discusses the water saving irrigation practices and ways to use agriculture around the world, including Uzbekistan. Relying on the ancient irrigation technologies used by ancestors and also modern irrigation methods, diferent irrigation water management technologies are presented to apply for various weather conditions and water availability situations. Suitable irrigation practices are discussed based on the water needs especially the arid countries, such as Uzbekistan. The results of an experiment conducted for hilly areas of Uzbekistan using “mulching” agro-technology is presented along with its suitability for Uzbekistan. Therefore, the expectations of sustainable water usage for irrigation is proposed.Publication Open Access IMPLEMENTING SAFE WORKING CYCLE (SWC) CONCEPT AMIDST THE COVID-19 CRISIS IN SRI LANKA(Ceylon Institute of Builders, 2022-06-26) Rasanjana, H.P; Allis, CThe phenomenon of COVID-19 has introduced critical challenges in the architecture, engineering, and the entire construction industry. A safe Working Cycle is a Japanese concept. It incorporates to enhances the effective implementation of safety management systems, thereby helping to prevent health and safety issues. This research mainly aims at identifying the strategies for overcoming barriers to implementing the Safe Working Cycle (SWC) concept during the COVID-19 pandemics in Sri Lanka. The research study focused more on reducing health-related illnesses caused by COVID-19 than on the other physical safety issues at the construction site. In such a critical health issue, the protection of human resources, an essential part of the construction industry, should be prioritized. The aim of the Study was reached through the sequential mixed method. The semi-structured expert interviews were initially conducted, and after that questionnaire survey was achieved among health and safety officers in construction projects in Sri Lanka. In the semi-structured interviews, data were analyzed using Nvivo thematic analysis software and questionnaire survey; M.S. Excel analyzed the collected data. Following the findings, several potential barriers were arisen to implementing the SWC concept in the Sri Lankan construction industry: including limited Budget allocation, poor safety attitude, limited land space, strict project schedules, and unawareness of workers. Further, this Study also indicated several potential practical strategies to overcome these barriers identified for SWC implementation. Such as; Implementing the COVID-19 bio bubble concept, Organizing regular toolbox meetings, demonstrating sign boards specific to this new concept, arranging separate systematic time slots, buildup a good communication network. The safe Working Cycle (SWC) is not currently practised in Sri Lankan construction culture. However, health and safety professionals are familiar with almost every aspect of the Safe Working Cycle (SWC); therefore, it is possible to put this into practice in the Sri Lankan construction industry. © 2022, Ceylon Institute of BuildersPublication Open Access EFFECT OF COVID-19 ON THE SMALL-SCALE CONSTRUCTION COMPANIES: THE CASE OF COLOMBO DISTRICT, SRI LANKA(Ceylon Institute of Builders, 2022-06-26) Gunarathna, N; Namarathna, C. PCOVID-19 is a global pandemic that has wreaked havoc on the lives of many individuals and has had a severe impact on the global economy. During this crisis, small and medium-scale businesses suffer the most and are the least prepared among all companies as per the previous studies done in other parts of the world. The majority of the small-scale construction firms in Sri Lanka act as subcontractors and generate job opportunities for a considerable number of people and are able to create a multiplier effect on the whole economy. However, it was observed that they are more vulnerable to the adverse impact of the pandemic. Thus, the principal goal of this research is to explore possible survival strategies to overcome critical financial issues of small-scale construction companies during the ongoing COVID-19 pandemic in Sri Lanka. A mixedmethod approach was adopted to gather the data for the study. A comprehensive literature review was carried out to identify the impact of COVID-19 on both global and local construction industries. The data for this study was gathered using semi-structured interviews and a comprehensive questionnaire survey with small scale construction company owners and construction industry professionals. The findings highlighted the key financial issues faced by the small-scale construction companies due to the pandemic including delays in client payments, supply chain management issues, frequent price escalation of construction materials, and inability to repay loans. The respondents suggested creating partnerships with financially strong companies, reduction of unwanted expenses, modifying supply chain channels and agreements, and ensuring business continuity plans as the strategies to be used to overcome the financial burden that occurred due to the pandemic.Publication Open Access Comparison of Instrumented Pile Load Test Results with Finite Element Simulation(World Congress on Civil, Structural, and Environmental Engineering, 2022-04-10) Diyes, G. H. I.; Thilakasiri, H.S.; de Silva, L.I.NDue to the proximity of the bedrock, rock socketed bored and cast in-situ piles are used to support the heavy super structure loads from the high-rise structures transferring to bedrock. In order to design single piles or group of piles, it is very important to know the carrying capacity of the bedrock in terms of skin friction distribution along the pile shaft and the load carried by the pile toe. Such information can be obtained by using the instrumented pile load tests but the instrumented pile load tests are expensive and not always carried out in most of the piling sites in Sri Lanka. In this study, it was aimed to find out the carrying capacity of cast in-situ bored single piles using commonly used finite element software PLAXIS 2D and compare the results with the instrumented pile load test results obtained in the field. Prior to the use of software package based on finite element analysis to find out the carrying capacity of the pile, the accuracy of the model used was verified by the results instrumented pile load test and the nearby borehole test results. Further, the differences and the difficulties of the interpretation of results with their potential reasons were discussed within the study. In the current study, the soil and rock properties were used from the nearby borehole results. It was shown that the best match results with the field instrumented pile load tests for weathered rocks were obtained when the elastic modulus for rock layers were twice the value suggested by Hong Kong geo guidelines (Geo,2006) whereas the best match results with instrumented pile load test results were given when half the value of the Young’s modulus of rock suggested by the Hong Kong geo guidelines (Geo,2006).Publication Embargo Wireless Power Transfer for Cardiac Pacemaker(IEEE Computer Society, 2022-08-17) Uthayakumar, U; Jayaweera, YCardiac pacemaker is an electronic device used to regulate the heartbeat of patients suffering with congenital heart defects. Considering the limitations in lifespan of current cardiac pacemaker battery, a wireless charging mechanism for cardiac pacemaker is proposed in this paper. Circuitry model and electromagnetic geometry is developed using Ansys Maxwell and Ansys High-Frequency Structure Simulator (HFSS) software to analyze three main technical issues such as: implantation, efficiency and safety. Specific Absorption Rate (SAR) and induced electric field in a 3-D model human body is evaluated by numerical analysis and simulation to ensure that the developed system adheres to safety limits proposed by Institute of Electrical and Electronics Engineers (IEEE) standard and International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.Publication Embargo Analysis and Quantification of Position Sensor Offset Error in Feedforward Controlled PMSMs(Institute of Electrical and Electronics Engineers, 2022-10-13) Edirisinghe, E. A. Y. G; Rajapaksha, L.T.W; Abeyratne, S. G; Kuruppu, S. SPermanent Magnet Synchronous Machines (PMSM) are popular in transportation electrification applications due to their inherent torque density and ease of control. In torque control applications, field-oriented control (FOC) ensures optimal torque production. However, PMSMs require a rotor position information for FOC, achieved with sensors such as encoder, resolver or linear hall sensor. Feedforward controlled FOC being one key form of PMSM control, the position sensor signal accuracy is paramount. Due to the harsh environments experience by systems in the transportation segment, the position sensor has the potential to misalign from the initially calibrated alignment. This paper focuses on the effects of such position sensor misalignment on feedforward-controlled drives. A novel quantification strategy to detect the failure mode has been presented with analytical details. The methodology is verified through simulation and validated by experimental results. Moreover, a brief analysis-contrasting the effects of position sensor misalignment on feedback and feedforward-controlled drives are presented.Publication Embargo The deflectors influence on flow complexity, bed morphology, sediment transport and water quality of urban lotic waters - A laboratory study(wiley, 2022-11-25) Sooriyaarachchi, D. T. A; Gomes, P. I. AIn this laboratory study different combinations of bed (sand, pebble gravel [gravel], and a mix of sand and gravel) and flow (typical and overtopping) were experimented with to investigate the impact of porous deflectors in flow diversity, water quality, and fish performance in prismatic open channels. Deflectors changed the gradually varied flow to a rapidly varied flow, as a sudden change in the water depth was observed at the deflectors, and this change was large for smooth beds. With the presence of gravel, the scouring near the downstream deflector was almost twice that of the sand bed, and with the scouring at its own upstream deflector, irrespective of whether the flow was typical or overtopping. This behavior was a result of sand mobilization due to shear stress and sand mobilization aided gravel transport. The mixed bed showed less gravel movement compared to the gravel-only bed. The percentage of sediment washed out was minor for all bed scenarios, indicating that sediment transport was local. Relative to the sand bed without deflectors (representing a typical urban canal), deflectors resulted in reduced and improved water quality (in terms of sediment load) for sand, and mixed bed, respectively. The fishes found refuge and were comfortable in the pool areas created by deflectors unlike in channels without deflectors where they showed exhaustionPublication Open Access Introduction of a Simple Estimation Method for Lane-Based Queue Lengths with Lane-changing Movements(Springer, 2022-12-21) Jayatilleke, S; Wickramasinghe, V; Amarasingha, NTraffic congestions are increased globally due to rapid urbanization and expedited economic developments in many countries. Vehicle queue is a governing aspect of traffic congestion, studied over the past decades. Most of the existing queue estimation approaches are limited to homogeneous traffic conditions. However, the traffic conditions in many developing countries are heterogeneous and are heavily influenced by mixed vehicle composition, lane changing, and gap-filling behaviours. This study aims to estimate the queue length at signalized intersections having heterogeneous traffic conditions. The heterogeneity was assimilated with the consideration of Passenger Car Units (PCU) in the measurements of the traffic flow and the lane-changing movement within the considered road section. The influential factors of the queue length were contemplated with the arrival flow, discharge flow, outbound lane change, inbound lane change, and signal configuration. A Vector Auto Regression (VAR) model was developed to estimate queue length, with a lag time of 15 s for each variable. The results have indicated a higher accuracy in the queue estimation as well as the practical application for prediction, constituting the traffic characteristics of the formed vehicle queue. The R squared of the VAR model was 0.97, along with a Mean Absolute Percentage Error (MAPE) of 21.55%. The model estimation results of right turning lanes were well accurate with MAPE ranging from 15 to 17%, whilst for through movement lanes, accuracy was slightly low with MAPE in the range of 23–26%. The study manifests the functionality of the developed methodology for accurate queue estimations, asserting the practical applicability of VAR models in other locations constituting mixed traffic.Publication Open Access A NOVEL TREATMENT FOR DETERMINING THERMAL CONDUCTIVITY OF THE SOIL SUBSTRATES FOR SELECTING SUSTAINABLE GROWING MEDIUMS IN TERMS OF THERMAL RESISTANCE(University of Montenegro, 2022-09-30) Kader, S; Jaufer, LThe Thermal conductivity of the soil is important to determine the horticultural performance of growing medium. Microclimatic features influence the viability of soil mixtures for vegetation. The goal of this study is to assess the heat conductivity of soil mixture samples comprising Coir, Biochar, Sawdust, Wood bark, and Compost in order to discover the best growth medium in terms of thermal resistance. Specimens were prepared by mixing 60% of raw materials with 40% topsoil and moulded into cylinders. Each sample were converted into semi solids and undergone for thermal conductivity apparatus measurements. Thermal conductivity of each specimen was determined using mathematical analysis based on experimental readings. The calculated results were used to deduce thermal resistance. Thermal conductivity values of all specimens were observed in the range from 0.64 W/mK to 0.91 W/mK. The maximum and minimum thermal conductivity magnitudes were exhibited by Sawdust (60:40) and Wood bark (60:40) respectively. In terms of suitability as a growing medium, Wood bark (60:40) contains highest thermal resistance while the lease thermal resistance was determined in Sawdust (60:40) due to its high thermal conduction. This research concludes that Wood bark (60:40) is the most convincing substrate in terms of thermal sustainability. © 2022, University of Montenegro. All rights reserved.Publication Open Access SOIL MANAGEMENT IN SUSTAINABLE AGRICULTURE: ANALYTICAL APPROACH FOR THE AMMONIA REMOVAL FROM THE DIARY MANURE(University of Montenegro, 2022-12-15) Shuraik, K; Novicevic, R; Jaufer, LThis study analyses the viability of converting the organic nitrogen possessed by dairy manure from Sri Lankan cows into ammonia using hydrolysis. Furthermore, ammonia removal from anaerobically digested dairy manure was evaluated with the experimental analysis. Hydrolysis was conducted to determine the impact of total solids, retention time, and temperature on the ammonia recovery. Experimental studies have shown that 85% of organic nitrogen in dairy manure was recovered into ammonia at 35O C within 7 days a 12.1 – 13.8 Total Solid (TS) content. Furthermore, it was also inferred that acidification occurs along with ammonium in the diary manure. Ammonia removal from anaerobically digested manure was investigated using Head Space Flushing (HSF), where it was identified that 73% of influent ammonia was removed at 35O C after 7 days. This result can be effectively used as an appropriate method for converting and removing ammonia from dairy manure in countries with large cattle herds. © 2022, University of Montenegro. All rights reserved.