Journal of Advances in Engineering and Technology [JAET]

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The Journal of Advances in Engineering and Technology (JAET) is an international, open access, double blind peer-reviewed journal. It is published by the Faculty of Engineering of Sri Lanka Institute of Information Technology (SLIIT). The JAET aims at fostering research and development work in Engineering and Technology and bringing researchers on to a common platform. Furthermore, JAET will also accept review articles on appropriate subject areas including concept papers of academic opinions, book reviews, etc. for publication therein.

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Open Access
Application of Sentinel-2 Satellite Data to Map Forest Cover in Southeast Sri Lanka through the Random Forest Classifier
(SLIIT, Faculty of Engineering, 2022-09) Gunawansa, T; Perera, K; Apan, A; Hettiarachchi, N
Sentinel-2 satellite data has been used for forest cover monitoring for almost five years. Mapping with Sentinel data will be a cost-effective solution for Sri Lanka, where the lack of updated land cover maps with high spatial resolution is a significant challenge in the land resource management of the country. A study area of about 5,000 km2 located in southeast Sri Lanka was selected for this study. Agricultural lands, forests including Yala national park, and villages with perennial crops make up the region. A Level-2A Sentinel-2 image with less than 10 percent cloud cover was used in the European Space Agency's (ESA) SNAP software version 8.0.0 for image processing and the forest cover of the study area was mapped through the Random Forest classifier (RFC). Normalized Difference Vegetation Index (NDVI) is also calculated as a Sentinel product to support RFC output. For RFC, ground truth data were collected through the reference of Google Earth high-resolution data. The classification accuracy was assessed using the Google Earth image as the reference dataset. Furthermore, RFC results were compared with NVDI greenness values. The classification accuracy was calculated using a confusion matrix (error matrix) through randomly selected 100 sample points. The overall accuracy of the land cover map was 85 percent, with a 96 percent accuracy for forest cover identification. The study found RFC as an effective method to isolate forest cover in Sri Lanka.
Open Access
Vertical Axis Wind Turbine for Sri Lankan Southern Highway
(SLIIT, Faculty of Engineering, 2022-09-22) Perera, S; Nandasena, D; Wijayakumara, D; Guruvita, K
Based on studies, most of the areas in Sri Lanka have an average amount of wind that could be resourceful in generating wind power. The area from Colombo along the coastal line to Matara is considered to have less wind potential. It’s a major disadvantage to the country’s energy generation plan as wind is one of the best renewable energy sources available in Sri Lanka. Concerning the energy crisis in the country, the necessity for a renewable energy source has arisen. Since renewable resources are used as standalone systems, the level of advancement increases while reducing the amount of stress on the main electrical grid when balancing the frequency. Highways can be followed as one of the country’s leading divisions that could be used for the use of renewable energy. The southern expressway in Sri Lanka requires an average of 375 kW of electricity only for lighting purposes. If the lights are turned on for 12 hours, then the amount of energy requirement is 4,500 KWh. It would save a considerable amount of energy from the national grid if that energy could be provided using renewable sources. This reduction of energy consumption from the main grid would benefit both the authorities of the Sri Lankan power system and the public. To address the aforementioned issue, a vertical axis wind turbine is proposed in this project to be installed on highways. The main requirements of the project are highlighted in the introduction and problem statement. All the details of the outcomes such as optimized rotor, gear system, generator and the PIC-based power management system are explained in detail with the steps taken to optimize the system at every possible step. There are plans which may facilitate the future development of the product included in the latter part of the document.
Open Access
Factors Affecting Red-Light Running of Pedestrians at Signalized Intersections
(SLIIT, Faculty of Engineering, 2022-09-22) Herath, C; Amarasingha, N
Hundreds of pedestrians have died and many have been injured in the past decades as a result of Red Light Running (RLR) infractions. According to the United States Department of Transportation, 846 pedestrians have died and 143,000 have been injured in 2019 due to RLR violations. The majority of previous studies have focused on pedestrian behavior at an intersection, whereas only a few have looked into pedestrian RLR violations. The main objectives of this research are to find the pedestrians’ RLR rate in Sri Lanka and to find ways to reduce the RLR rate of pedestrians at the signalized crossing. Video observation surveys were conducted to collect data at three signalized intersections within Kandy city limits during weekdays for two hours per site. Pedestrian demographic variables such as gender and age; crossing characteristics such as crossing type, direction, crossing speed etc; and site characteristics such as crossing length, pedestrian green time, etc. were recorded. Chi-square and binary logistic regression tests were done. Results showed that out of 178 females, 130 had compliance with signal phases and out of 386 males, only 215 had compliance with RLR of a pedestrian. Furthermore, other independent variables such as age, crossing type, direction etc. were also associated with compliance RLR of pedestrians under Chi-square results. Based on the results of binary logistic regression, the variables such as gender, crossing type, number of traffic lanes, and pedestrian speed are significant when decreasing the log of probability -0.658, -3.040, -1.022 and -2.556 of compliance for RLR respectively. Variables that crosswalk utilization are also significant when increasing the log of probability of RLR 1.406 of compliance for RLR. The results would help develop safer pedestrian infrastructures and engineering countermeasures as well as assist the researchers and practitioners in better understanding pedestrian crossing behavior at signalized intersections.
Open Access
Developing a Rubber based Nanocomposite
(SLIIT, Faculty of Engineering, 2022-09-22) Sadique, M. I. F
Polymer compounds such as Natural Rubber (NR), which consists of compounds such as isoprene, are capable of being processed for the manufacture of a range of rubber based products for a large variety of applications. The properties of a natural rubber compound are susceptible to enhancements in their properties through the incorporation of nanofillers into its matrix. This study addresses the preparation of a natural rubber based nanocomposite that utilizes graphene as a nanofiller for the facilitation of the required enhancement in the rubber compounds properties. The nanocomposite specimens used in the study were prepared by means of acid-coagulation. The acid-coagulation formulation utilized was adapted from methodologies employed in commercial applications. The enhancement in the rubber properties due to the incorporation of the nanofiller was validated by means of mechanical testing. Prior to the testing, the applicable standard for tensile property testing was identified to be ASTM D412. Through the acclaimed standard, a mould to facilitate the preparation of the required specimens was 3D printed from PETG. The primary aim of the study was to determine the effect of large concentrations of graphene (beyond 2.5wt %).The results from the mechanical testing of the acidcoagulated samples exhibited enhancements in the elongation at break and tensile strength between unfilled NR and the graphene filled NR nanocomposite. With the incorporation of 5wt% of graphene, the elongation at break of the rubber increased to 687%, showing a 25% increase. The tensile strength of the rubber increased to 4.07 MPa, showing an enhancement of 102% in comparison to the pristine rubber compound.
Open Access
Attributes of ADR in the Sri Lankan Construction Industry
(SLIIT, Faculty of Engineering, 2022-09-22) Edirisinghe, V; Marsh, D; Borthwick, F; Siriwardena, M; Cotgrave, A
Alternative dispute resolution (ADR) methods were introduced to the construction industry to avoid the negative effects of litigation in relation to the cost, time, and business relationships of a construction project. This study focused on identifying the current ADR practices in the Sri Lankan construction industry and examined the specific attributes of each method to create a more effective process. A qualitative research strategy was carried out with interviews with industry professionals working in the Sri Lankan Construction Industry. Content analysis using NVivo software was used to analyse the data. The key findings revealed that the neutral third party has good knowledge of construction. Despite the differences in each ADR method, disputing parties do not have the confidence in the neutral third party or trust in the process. This study also revealed that the unavailability of these key attributes will finally affect the cost and reputation of the ADR methods. Therefore, the research suggests that to improve the ADR process and its success there should be awareness studies on ADR methods and training for ADR practitioners within the Sri Lankan Construction Industry.
Open Access
Understanding the Characteristics of the Heatwaves using Temperature as the Only Variable – A Case Study on the Heatwaves in 1994 in South Korea
(SLIIT, Faculty of Engineering, 2022-09-22) Chandrasekara, S. S. K; Kwon, H. H
Acutely warm weather coupled with extreme weather variables or latent cooling due to a deficit of soil moisture could generate heatwaves. South Korea is highly susceptible to heatwaves that occur annually in different intensities and cause devastating impacts. This study aimed to identify the characteristics of the heatwaves, especially focusing on one of the most severe heatwaves observed in 1994 in South Korea using only temperature as a variable. The summer season, June to September (JJAS), was selected for the study because heatwaves were prominent during the summer in South Korea. The maximum and minimum daily temperatures were collected from the 67 meteorological stations located in South Korea. The mean daily 95th percentiles of the temperatures were assessed to identify the heatwave durations and the intensities. In 1994, the 15 stations recorded their highest heatwave durations, and durations varied between 48 to 66 days in the JJAS season. Busan station recorded the highest heatwave duration in 1994, which persisted for 66 days or throughout half of the season. Further, it was interesting to identify that coastal meteorological stations were most vulnerable to heatwaves in South Korea. However, the relationship between temperature intensities and heatwave duration for coastal cities showed statistically low significance. Furthermore, it is identified that the daily maximum temperature was most influential in the occurrence of heatwaves in both the coastal and mainland meteorological stations, except for Pohang and Ulleungdo. Therefore, the characteristics of heatwaves observed in 1994 in South Korea were identified using temperature as the only variable. Furthermore, a study on the dynamic atmospheric oscillations due to heated waves in coastal regions of South Korea over characteristics of heatwaves observed in South Korea is suggested
Open Access
Design and Dynamic Modelling of Knee Exoskeleton for Disabled People through ADAMS-Simulink Co-simulation
(SLIIT, Faculty of Engineering, 2022-09-22) Ranaweera, J. P; Perera, M
This paper is written to outline the progress and findings of an undergraduate research project aimed at the designing and modelling of an exoskeleton design of the knee joint for rehabilitation and gait support. It focuses on the rehabilitation potential of the proposed exoskeleton design on patients with Hemiplegia and Monoplegia conditions with the objective of seeking a feasible, simple means of joint actuation to reduce the complexity of the design. Exoskeleton designs are able to provide rehabilitation and improve the overall quality of life of disabled people globally. However, a common issue found almost everywhere is the costly nature of the exoskeletons that are available in the market now as they are exclusive devices, which makes them inaccessible and impractical to the general public, especially in developing countries. Initially, the paper focuses on the review of relevant literature and previous research and evaluating the designs that have been developed as of now. A thorough analysis of the work done by previous researchers and companies was conducted to gather data on the underlying engineering principles and techniques used for the exoskeleton development as well as any limitations or restrictions to the process. Conceptual designing of the possible solutions was developed using the understanding and knowledge gathered during the literature review. The selection of the best solution was based on the analysis of the pros and cons of all the solutions. The chosen design, utilising a 4-bar mechanism, was then modelled using SolidWorks software to provide a clear visualisation of the system. The kinematic and dynamic analysis of the mechanism was evaluated to analyse the possibility of using the proposed exoskeleton design by replicating the model in ADAMS multibody software. The dynamic analysis was conducted by using the co-simulation platform between ADAMS and Simulink to enable the addition and control of feedback loops within the system. The results of the analysis show that the design can achieve the required motions of the human gait cycle, especially during the swing phase of the gait cycle. The analysis of the actuation torques and reaction forces on the human body showed that an acceptable torque range was possible during the swing phase of the gait cycle.
Open Access
Evaluating the Effectiveness of Speed Humps Related to Speed Profile and Noise Profile
(SLIIT Faculty of Engineering, 2023-03-02) Gamlath, K.G.D; Amarasingha, N; Wickramasinghe, V
Speed humps are an effective traffic calming measure to improve the safety of road users. On the other hand, speed humps have certain drawbacks, such as increasing emergency response time, causing damage to cars, and high noise levels due to excessive traffic. These impacts further vary with different hump profiles. Thus, the primary objective of this research is to investigate how the geometric profile of speed humps affects vehicle speed and noise level. The secondary objective is to find the Level of Service in the presence and absence of a speed hump by using VISSIM microsimulation. In this study, Lake Drive Road, Nawala, was selected with four different speed hump profiles. The Sound Meter smartphone application was used for noise monitoring. A drone camera footage was utilized to capture vehicle flows while speed trajectories of each vehicle were developed using tracking software. The developed speed profiles were used for the simulation purpose. Then, a Multiple Linear Regression (MLR) model was developed and validated to predict the hump height for the desired speed reduction and desired noise level for each selected four-vehicle category. Further, the average noise levels were found to be higher than the Central Environmental Authority's permissible noise level, and it increases with the height of the hump. It was also observed that as the height of the hump increases, vehicle speed decreases. The largest speed reduction, 42.13 %, was observed in passenger cars, while the lowest speed reduction, 23.5 %, was observed in motorcycles. Therefore, speed analysis findings reveal that passenger cars have a significant speed reduction when compared to other categories. However, the average speed reduction for all vehicles was identified as 33.85 %, and VISSIM simulations revealed that the average Level of Service (LOS) drops to LOS C from LOS A due to the presence of the speed hump.
Open Access
Experimental Identification of Alkali-Aggregate Reaction in Concrete
(SLIIT, Faculty of Engineering, 2023-03-02) Baddeliyanaralalage Don, R
Several advanced and time-consuming methodologies have been developed to detect Alkali-Silica Reaction (ASR) in suspected structures. The main objective of this research study was to identify a reliable experimental procedure for detecting ASR in existing concrete. A simple staining solution is used here to detect ASR in concrete specimens. The staining reagent employed here is Sodium Cobaltinitrite, which is used in the Los Alamos staining method to detect ASR. Sodium Cobaltinitrite can identify potassium-rich ASR gel by staining it yellow for rapid field screening purposes. Reactive and control concrete specimens were cast to get some experience with this test and to verify whether this test can be used in a suspected concrete structure. Waste white soda-lime glass aggregate was used to cast reactive concrete specimens, whereas natural coarse aggregates were used to cast non-reactive concrete specimens. Testing was carried out in two batches. Each batch consisted of six reactive and six control concrete specimens which were cured in the above-mentioned solutions. The first batch was examined after 44-days and the second batch was tested after 60-days of casting. Results of this test showed that reactive concrete specimens cast using glass displayed yellow stains as expected, demonstrating the presence of potassium-rich ASR gel on the concrete surface. Employing NaOH as a curing medium had accelerated ASR. There is a limitation in the method when utilizing KOH as a curing agent. It is concluded that Sodium Cobaltinitrite can be used as a method for rapid identification of ASR in the preliminary stages of experimental identification of the alkali-aggregate reaction in an existing concrete structure.
Open Access
Data Science to Determine Mechanical Properties of Low Carbon Steel During In-Process Inspections
(SLIIT, Faculty of Engineering, 2023-03-02) Alahapperuma, K. G.; Suraweera, D. D. D.; Nandhakumar, N.
Carbon steel is a widely used category of engineering metal, mainly due to its attractive mechanical and fabrication properties and low cost. The chemical composition, physical parameters, and mechanical properties of carbon steel are maintained as per the specified standards, and local steel should be complied with Sri Lankan Standard 375: 2009. Generally, the chemical composition is tested during melt stages, and mechanical properties are tested for finished products. Since it is necessary to ensure products comply with the standard, mechanical properties are tested during in-process inspections as well. When the results are not within the acceptable range, a considerable amount of production has to be rejected, causing a loss to the manufacturers. If the results of the in-process inspection are instant, it will help make suitable adjustments to process conditions and thereby prevent rejection of products, while reducing quality assurance costs, as well. Therefore, the objective of this study is to predict tensile properties with chemical composition, as input variables, to be used for in-process inspections. Forty mechanical test reports were collected from a steel manufacturing factory for 12 mm diameter, thermo-mechanically treated (TMT) steel bars. Each test report is of 15 samples from the respective batch, and consists of corresponding chemical composition and physical parameters. Multiple linear regression analysis was applied to each batch, using Statistical Package for the Social Sciences (SPSS) software, to predict yield strength (YS), ultimate tensile strength (UTS), elongation at break (EB) with carbon equivalent value (CEQ) and percentage of Sulphur as inputs. Relationships between variables were not significant, even though those relationships can be used to predict tensile properties. The predictions may not be reliable, due to the limited conditions of the study and assumptions made. It is therefore recommended to apply multivariate regression analysis or Artificial Neural Network (ANN) techniques, with other chemical elements, process temperature and water flow rate etc. also as input variables.
Open Access
Efficient Ventilation Configurations for an Isolation Ward in View of Reducing the Potential Contamination of Its Occupants
(SLIIT, Faculty of Engineering, 2023-03-02) Durage, H; Attalage, R; Bandara, R.M.P.S.
The rise of respiratory infections, such as the SARS epidemic in 2003, and the H1N1 influenza epidemic in 2011, highlighted the importance of efficient ventilation in healthcare facilities. The novel SARS -Cov-2 disease has sparked many concerns over the ventilation performance of multi-bed isolation wards and their ability to suppress airborne infectious contamination. The study is primarily based on suggesting ventilation improvements for a locally acquired multi-bed intensive care isolation unit. The study via ANSYS -fluent incorporates a k-𝜀 turbulent model that is used to analyze exhaled CO2 particle tracks of 4 human models. Three ventilation strategies, namely, Displacement, Stratum, and Curtain -Air-jet are initially considered and evaluated based on two indoor air quality indices (IAQs), namely, air change efficiency and contaminant removal effectiveness. Stratum ventilation comfortably exhibits unidirectional flow characteristics with an air change efficiency of 0.946, which was obtained through ANSYS -CFX while each suggested configuration is capable of achieving a contaminant removal effectiveness value greater than 1 which depicts that the contamination source is not in a perfect mixing zone. Results provided inconclusive evidence to draw correlations between the two IAQ indices and thus it is confirmed that these indices solely depend on the type of ventilation strategy. Contaminant concentration on health care worker breathing plane and exhaled particle tracking for 4 minutes in each analyzed configuration revealed that both Stratum and Curtain air-jet models improve the escaped particle efficiency by 25% and 29% respectively compared to the base model. These models are further compared against reference values specified by guidelines to evaluate their suitability for real-world operation.
Open Access
Neural Network based automated hot water mixture
(SLIIT, Faculty of Engineering, 2023-03-02) Firsan, F.N.M; Herath, G.M; Thilakanayake, T.D
In the present day and age, most residential spaces comprise a shower system and generally a conventional system of hot water showers. Throughout history, showering has developed as an essential need in a person’s life. Nevertheless, a typical hot water shower system comprises delays in hot water mixing and usually requires an average of 2 to 4 minutes to mix the cold and hot water to deliver the appropriate shower temperature. The delay in mixing provides less comfort and poor satisfaction affecting people’s lifestyles. Due to these disadvantages, a system incorporating artificial Intelligence can be utilized to enhance the performance of mixing which can offer an automated hot water mixture system with improved efficiency and effectiveness. Recently, significant research has been focused on utilizing deep learning technology due to its multiple breakthroughs in fabricating a broad range of automated novel applications since Neural Networks comprise the capacity to learn from data to offer efficient and accurate systems. In this research project, the hot water mixture is employed by an Artificial Neural Network model integrated with the combination of an embedded system of the proposed system of hot water mixture. Furthermore, the proposed system comprises temperature and flow sensors along with controllable flow valves. The tested system indicated acceptable accuracy between the actual and desired output flow rate and temperature.
Open Access
Strategies Used by the Sri Lankan Construction Industry to Overcome the Challenges Posed by the Covid-19
(SLIIT, Faculty of Engineering, 2023-03-02) Fernando, P; Gunarathna, N
The global outbreak of the COVID-19 pandemic has thrown the world's political, social, economic, religious, and financial structures into disarray. COVID-19 has a broad range of effects on numerous industries, including construction. Sri Lanka as a developing country is also affected by the pandemic and many sectors of the Sri Lankan economy such as construction, education, tourism, imports and exports, agriculture, and health etc are experiencing negative consequences of the pandemic, Construction industry as one of the key sectors of the economy was also severely affected by the COVID-19 global pandemic in various ways. Construction companies and government institutes are taking action to face these challenges. This study describes how COVID-19 impacts the local construction industry throughout the construction process. Furthermore, the impact was evaluated with regard to several aspects namely, financial, human resources, supply chain and logistics, legal, and completion and handover of the project. The strategies which are used by the construction industry participants to face the challenges of the pandemic are also discussed. A mixed research approach was used in the study and questionnaires which comprised of both qualitative and quantitative questions were used as a data collection tool. This research revealed new knowledge about the construction industry in relation to the COVID-19 pandemic. The study's most important finding was that the spread of the virus influenced the entire construction process. The pandemic had a major impact on the construction stage as well as the human resources aspect of the industry.
Open Access
Review on Sub-Synchronous Resonance Damping with Thyristor Controlled Series Compensators
(SLIIT Faculty of Engineering, 2023-03-02) Weerakoon, D. R.; Annakkage, U. D.; Karawita, C.
Over many years, the power industry has used series compensation with fixed series capacitors for long-distance ac power transmission. With the availability of Thyristor Controlled Series Compensators (TCSC), utilities have the option of using them instead of fixed series capacitors to exploit the advantage of their flexibility and controllability. The use of TCSCs for damping electro-mechanical oscillations and Sub-Synchronous Resonance (SSR) has been investigated and reported over the years. This paper presents a review of those techniques to damp SSR problems associated with conventional multi-mass turbine generator systems in series compensated networks. This paper also demonstrates that SSR can be damped out with the proper choice of TCSC parameters and/or control strategies even without an auxiliary damping controller. Sub-synchronous behavior of the TCSC is simulated in both open loop and closed loop controls in the time domain through Electro-Magnetic Transient (EMT) simulations. IEEE 1st Benchmark model for SSR studies is used in this paper to demonstrate the effect of TCSC parameters and control methodology in damping SSR.
Open Access
Contact Position Estimation in the Event of Simultaneous Multiple Contacts in Vision-based Tactile Sensors
(SLIIT, Faculty of Engineering, 2023-10) Senarath, W. A. T. N; Fernando, S. A. W; Rajakaruna, R. M. T.P
Tactile sensors are used to detect physical contact or pressure. They provide feedback about the physical environment and allow more natural and intuitive interaction with machines. Tactile sensors have many applications in the fields of agriculture, space exploration, health and automotive. Capacitive, resistive, as well as vision (optical) based tactile sensors have been proposed in the literature. This paper proposes a novel approach to solving the problem of estimating the contact locations in the event of simultaneous multiple contacts in vision-based tactile sensors. The relationship between the contact force and the resulting physical deformation of the sensor material of a large-scale tactile sensor was studied with the aid of a custom-built hardware unit. Hardware architecture consists of a custom-designed flat rectangular sensor surface coupled with a mono-vision camera to capture the surface deformation. This method can capture detailed information on the resulting deformation for multiple simultaneous contacts. A software -based deformation estimation algorithm is proposed, where the grid array of marker positions was estimated with a tracking algorithm, an estimation algorithm, and a graphical representation algorithm. Moreover, separate analyses have been carried out to find the best suitable method to observe the deformation of the sensor material. In this study, the approach that was taken to find the contact position and deformation, produced results with an accuracy of more than 97%. Consequently, these results show that this method outperforms existing state-of-the-art techniques in terms of accuracy in the detection of the contact position.
Open Access
Off-Grid Wind-Solar Hybrid Energy System for Analaitivu Island in Sri Lanka
(SLIIT, Faculty of Engineering, 2023-10) Liyanagama, N; Ravindra, D; Bopitiya, P; Guruvita, K
The objective of this project is to implement an off-grid wind-solar hybrid energy system with a battery bank system for Analaitivu island in Sri Lanka, which has no connection to the main grid. The hybrid model is developed by analyzing the wind-solar weather pattern of the island to fulfill the energy demand by choosing the ideal combination of solar cells and wind generators
Open Access
A Spring – Loaded Actuator Developed By DC 3481 Silicone / Polyaniline – Based Dielectric Polymer Film
(SLIIT, Faculty of Engineering, 2023-10) Dissanayake, D.M.N.T.; Wijerathne, W.D.C.C.; Shakaf, S.; Samaraweera, M.A.R.L.; Asela, A.U.; Premarathna, A.K.C.P.
Dielectric polymer films play a significant role in soft robotics in actuator development. Silicone and acrylic materials are commonly used for creating dielectric polymer films with superior properties compared to other potential materials such as PVDF and Polyurethane. Published literature reports applying different fillers to enhance the electromechanical response of dielectric polymers. Starting with an already-reported novel dielectric polymer based on polyaniline/DC 3481 silicon, we report the fabrication and characterization of a spring-loaded actuator. Here we developed a simple spring-loaded actuator, and three different designs were used to optimize the actuator design. As per research outcomes, it can be concluded that paper tie-based clamping provides the best configuration for the actuator in terms of high deflection and low tendency to short-circuit. The developed actuator renders the maximum deflection of 4.19 mm at 2 kV voltage, and the actuation time is approximately 115 s. The proposed actuator is superior to many reported actuators in terms of maximum deflection and corresponding voltage. The proposed actuator and the corresponding dielectric polymer thus have potential applications in developing actuators for haptics with comparatively high deflection.
Open Access
Comparative Lifecycle Analysis of Sri Lankan Non-Conventional Roofing Materials
(SLIIT, Faculty of Engineering, 2023-10) Fernando, W.A.N; Karunaratne, S
Building materials, especially roofing products, play a major role as they are essential for any building construction. Knowledge of the environmental performance of building materials is vital when building life cycle assessment. However, only a few studies have been conducted in Sri Lanka in this regard. The present study focuses on the environmental life cycle assessment of two different nonconventional roofing materials used in Sri Lanka. Acrylonitrile Styrene Acrylate roofing sheets and Calicut-type clay roofing tiles have been selected for the study. In order to measure and calculate environmental impacts of both types of roofing materials, field data was collected quantitatively and noted as per ISO14040 and ISO14044. Using the Cradle-to-Gate LCA technique and OpenLCA software, the environmental impacts as midpoint and endpoint categories were evaluated. As the main output of the study, environmental performance of these two roofing materials were compared, the hotspots of the manufacturing process and the causes were also identified. . Accordingly, the global warming potential of Acrylonitrile Styrene Acrylate roofing sheets and Calicut-type clay roofing tiles is 13.5 kgs of CO2 eq. and 8.95 kgs of CO2 eq. respectively. Further, comparison of the endpoint categories showed the resource depletion was most impactful, indicating 0.814012 points and0.65305 points, respectively for the two roofing material types. Further, kiln firing was identified as the environmental hotspot contributing most to the endpoint and midpoint impact categories for clay roofing tiles, while mixing materials by hot mixer was the hotspot for Acrylonitrile Styrene Acrylate roofing sheets. In addition, the overall results demonstrated how the production process of clay tile influences more than the Acrylonitrile Styrene Acrylate roofing sheet on both the midpoint as well as the endpoint impact categories.
Open Access
Evaluation of Mechanical Characteristics of Rice-Husk-Bricks
(SLIIT, Faculty of Engineering, 2023-10) Tilakasena, R.S; Tharmarajah, G
Construction activities and materials extraction are major contributors to environmental pollution. To address this issue, the utilization of bio-based materials presents a promising sustainable alternative for the construction industry. Bio-based materials encompass a broad category of organic matter that can be either synthesized or naturally derived. One such noteworthy bio-based material is rice husk, which exhibits pozzolanic properties. Abundantly available as an agricultural waste product, rice husk holds potential as a viable substitute in construction processes. This study is dedicated to investigating the feasibility of replacing fine aggregates, traditionally comprised of sand, in cement blocks with untreated rice husk on a volumetric basis. In contrast to being used merely as an additive, this research delves into the possibility of substantially replacing sand with a higher proportion of rice husk, ranging from 20% to 80%, in the composition of cement blocks. The findings of this study reveal that up to 40% of the sand content in cement blocks can be effectively replaced with untreated rice husk while still meeting the requisite strength standards for non-load bearing blocks. Moreover, this study demonstrates an additional advantage in terms of weight reduction. Substituting sand with rice husk leads to a remarkable 30% reduction in the overall weight of the blocks. These results underscore the potential benefits of integrating rice husk into construction materials as an environmentally friendly and weight-efficient alternative.
Open Access
Prediction of Post-Construction Settlement of Road Embankment on Soft Soil Deposits
(SLIIT, Faculty of Engineering, 2023-10) Vidurapriya, K. V. D.; Jayaratne, G. A. N.; Thilakasiri, H. S.
Organic soils are often considered problematic soils around the world due to several reasons. Excessive settlement is one of the main concerns when constructing infrastructure on soft grounds with organic soil deposits. Ground improvement is mainly carried out on the sub surfaces that lack the strength and stability to bear the structure to be constructed and undergo large settlement during operation. Different soft-ground treatment methods must be applied based on the soil properties to reduce the expected settlements during construction and operation periods. In this context, it is essential to know the behaviour of the subsurface after the ground improvement process. This study mainly investigates the accuracy of the settlement prediction methods during the post-construction stage of the Colombo-Katunayake Expressway Project in Sri Lanka. Settlement prediction was done for the Defect Liability Period using the hyperbolic method, the Mesri method and the Ladd method. A comparison of the predicted settlement with the measured field settlement was done to assess the accuracy of the settlement prediction methods. The comparison showed that the hyperbolic method was more accurate and convenient for predicting the settlement of the embankment.