SLIIT International Conference On Engineering and Technology Vol. 03 [SICET] 2024

Permanent URI for this collectionhttps://rda.sliit.lk/handle/123456789/3767

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Data-Driven Bioclimatic Zoning in Sri Lanka: PCA and Clustering Analysis
(SLIIT, Faculty of Engineering, 2024-10) Nadarajah, P.D; Singh, M.K; Mahapatra, S
Driven by evolving lifestyles and the escalating demand for thermal comfort, Sri Lanka faces a critical absence of climate zone classifications necessary for constructing energy-efficient and climateresponsive buildings. This study addresses this gap by implementing bioclimatic zoning using a comprehensive 31-year weather dataset of 25 locations across the country. By applying Principal Component Analysis and Hierarchical Clustering to the 31-year weather data, Sri Lanka was classified into three distinct bioclimatic zones: Z1 (Hot and humid), Z2 (Cool and humid), and Z3 (Warm and humid). Bioclimatic potential analysis for each zone reveals natural ventilation as the most effective passive design strategy, demonstrating potential percentages of 64 ± 13%, 63 ± 10%, and 83 ± 4% in a year for Z1, Z2, and Z3, respectively. These findings underscore the crucial role of bioclimatic zoning in guiding the design of energy-efficient buildings in Sri Lanka. The approach contributes significantly to achieving national energy efficiency goals by leveraging climate-specific passive design strategies and reducing reliance on energy-intensive cooling systems. Moreover, the study not only classifies Sri Lanka into three bioclimatic zones but also emphasises the broader impact of implementing such strategies on sustainable construction practices. This research, therefore, stands at the intersection of bioclimatic zoning, sustainable building practices, and the evolving energy landscape.
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Analysis of Service Quality Expectation of Passengers: Case Study of Colombo Fort Railway Station
(SLIIT, Faculty of Engineering, 2024-10) Jayathilake, M.N; Fernando, S.S.S.; Madushanka, P.G.D.; Sharic, A.H.S
This study investigates passenger perceptions of service quality at Colombo Fort Railway Station using the SERVQUAL model, focusing on five key dimensions: tangibility, reliability, responsiveness, assurance, and empathy. By examining demographic characteristics such as gender, age, income, frequency of use, trip purpose, and time of travel, this research aims to identify significant differences in service quality expectations among diverse passenger groups. Data were collected from 300 passengers through a structured survey and analyzed using t-tests and ANOVA. The findings highlight critical areas for improvement, including enhanced schedule adherence, improved communication, and better maintenance of station facilities. Notably, the study reveals that daily and weekly commuters report lower satisfaction levels with train punctuality compared to occasional users, while older passengers express higher satisfaction with emergency response and lost item retrieval services. These insights provide valuable recommendations for Sri Lanka Railways to enhance service quality, thereby increasing passenger satisfaction and loyalty. The study underscores the importance of tailored service improvements to meet the specific needs of different passenger demographics, contributing to a more efficient and reliable railway system in Sri Lanka.
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Potential Use of Partnering Procurement to Minimize Project Delays in Private-Sector Construction Projects
(SLIIT, Faculty of Engineering, 2024-10) Hasaranga, K.K.A.P; Bandaraa, R.P.H.S.
Project delivery delays remain a critical factor for project success in private-sector construction projects. This research explores the potential of Partnering Procurement as a strategic approach to minimize project delays. Partnering Procurement emphasizes collaboration, transparency, and long-term relationships among project stakeholders, including clients, contractors, and subcontractors. The study aims to investigate Partnering Procurement's effectiveness in minimizing project delays in private-sector Construction projects. The research methodology encompasses a comprehensive literature review and quantitative data collection method. The survey will be designed to collect quantitative data on the benefits and challenges associated with partnering procurement and its effectiveness in minimizing project delays. The anticipated outcome of this research reveals key contributors to delays in privatesector construction projects. Financial problems and payment delays from clients, drawing submission delays from consultants, and improper project management from contractors stand out as critical factors. This research includes a deeper understanding of the benefits and challenges of partnering procurement in private-sector construction projects. The findings will contribute to the body of knowledge in construction management and guide project stakeholders on the effective implementation of partnering procurement to minimize project delays. By minimizing project delays, private-sector construction projects can enhance their competitiveness, deliver projects within budget and schedule, and ultimately satisfy the needs of clients and stakeholders.
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Auto-encoder Based Data Clustering for Typical and Atypical Repetitive Child Hand Movement Pattern Identification
(SLIIT, Faculty of Engineering, 2024-10) Wedasingha, N; Samarasinhe, P; Seneviratne, L; Papandrea, M; Puiatti, A
This study is dedicated to the important task of identifying unique repetitive hand movement patterns in children, with the aim of facilitating early anomaly detection. The current body of literature lacks a comprehensive model capable of effectively discerning distinctive patterns in child repetitive hand movements. To address this gap, our innovative approach employs autoencoders to efficiently compress intricate data and extract latent features from a dataset with inherent limitations. By utilizing clustering techniques, we analyze these features to reveal distinct behaviors associated with child hand movements. Despite the challenges posed by binary annotated datasets, our model demonstrates outstanding performance in categorizing movements into four distinct types, thereby providing valuable insights into the intricate landscape of child hand movement patterns. Statistical assessments further underscore the superiority of our autoencoder, achieving a mean Bayesian value of 0.112, outperforming state-of-the-art algorithms in this domain. Subsequent in-depth analysis exposes notable inter-cluster patterns, elucidating transitions from typical to atypical behavior in child hand movements. This research constitutes a significant advancement in the field of child hand movement pattern analysis, offering a powerful and sophisticated tool for healthcare professionals and researchers alike. The automation capabilities embedded in our model empower these professionals to address childhood behavioral disorders more effectively and efficiently. In essence, our research not only contributes to the enhancement of early anomaly detection systems but also serves as a valuable resource for professionals engaged in child healthcare and behavioral research, facilitating a deeper understanding of these nuanced patterns.
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Investigation of the Stability of Embankments on Soft Soil Deposits
(SLIIT, Faculty of Engineering, 2024-10) Robinson, C.F; Thilakarathne, T.M.D; Thilakasiri, H.S
In geotechnical engineering, the stability of embankments built on soft soil deposits is crucial because low shear strength, high compressibility, and high-water content in soft soils make them vulnerable to lateral spreading, settlements, and slope failures. There are several ground improvement methods that have been utilized to improve ground stability. However, it is essential to investigate the stability of the embankment that has been constructed on soft soils even if ground improvement techniques have been adopted. This research mainly focuses on investigating the stability of the embankment sections that have failed in Colombo-Katunayake Expressway project, which has already adopted stone column installation as a major ground improvement technique. This research has focused on three primary failing sections, which are K6 + 230 – 320, K7 + 890 – 980, and PK1 + 700 – 800. To investigate the stability of the failed sections of Colombo-Katunayake Expressway project, observational approach methods have been used instead of stability analysis or other numerical methods. The observational approach methods this research focuses on include the construction control diagram developed by Matsuo and Kawamura and the construction control chart developed from an instrumented trial embankment on soft ground at Tokai, Kedah, Malaysia. These observational approach methods have included fill height, lateral displacement, and vertical settlement as essential observed metrics. Additionally, certain successful portions of the CKE project have been plotted using both observational approach methods to make sure the curves produced make a truthful statement and to apply these techniques to the construction of embankments in the future. By the use of the observational approach methods, the most suitable method that can be used to identify and control the stability of the embankment has been selected.
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Determination of Shrinkage of Mud Concrete
(SLIIT, Faculty of Engineering, 2024-10) Kuruppu, K.D.S.; Dharmaratne, P.D.; Galabada, H.G.
The research study systematically examined the shrinkage of mud concrete, aiming to evaluate its potential as an eco-friendly construction material. It investigated the influence of water-retarder admixture and coir fiber additions on dimensional changes, utilizing ASTM C157 as the test method. The study is required to address knowledge gaps in mud concrete shrinkage characteristics and provide guidance for its sustainable construction application. Three primary objectives were identified: analyzing shrinkage, determining optimal curing times for shrinkage minimization, and assessing the impact of fibers and admixtures on the shrinkage process. The mix design incorporated locally available soil, ordinary Portland cement, coconut fiber, water, and a water-retarder admixture (Plastolith 55R) to improve workability and structural integrity. Results indicated a consistent length reduction in all mud concrete compositions over time, with the water-retarder admixture and coir fiber effectively mitigating shrinkage. However, fiber addition was observed to increase shrinkage, necessitating further investigation. Wet curing conditions significantly reduced shrinkage compared to dry conditions, underscoring the importance of moisture content during curing. The study concluded by highlighting the crucial role of water-retarder admixture in reducing mud concrete shrinkage and enhancing longterm performance. It acknowledged the observed increase in drying shrinkage rate with fiber addition, emphasizing the need for additional research into underlying processes. Overall, the study provides valuable insights into sustainable construction practices by advocating for judicious additive use to optimize mud concrete compositions and calls for further research to explore fundamental mechanisms influencing shrinkage.
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Associations Between Socioeconomic and Trip Characteristics of Bus Passengers to Plan for Transfer-Based Bus Transport Operations (TBBTN)
(SLIIT, Faculty of Engineering, 2024-10) Silva, K.N.R.; Sharic, A.H.S.; Bandara, J.M.S.J.
Sri Lanka's bus transportation system relies heavily on direct routes connecting main town or city centers, leading to operational challenges such as route overlap, increased fleet requirements, and financial losses. To address these issues, this study advocates for a transfer-based bus transportation (TBBTN) approach. The proposed strategy involves shortening route lengths, boosting service frequency, and minimizing overlap to potentially enhance revenue per kilometer for operators. However, this approach introduces passenger inconvenience as travelers are required to switch buses. Analyzing the associations between passenger socioeconomic characteristics and trip characteristics is crucial for effective TBBTN planning. Data was collected through interviews with randomly selected passengers, and the study revealed that as passengers' ages increased, their service expectations rose, with younger passengers expressing concerns about trip costs. The TBBTN aims to streamline transfers and reduce travel expenses, catering to diverse income groups. The positive correlation between income levels and service expectations supports the potential for TBBTN to offer improved amenities. With buses being widely used for work and educational trips and considering reduced car ownership among young and middle-aged passengers, TBBTN emerges as an affordable alternative. The study also emphasizes the importance of addressing gender-specific service expectations, particularly safety concerns among females, by establishing well-lit and secure transfer points. Ultimately, the proposal recommends prioritizing passenger expectations, affordability, and addressing diverse demographic needs to enhance the overall transportation experience for all.
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A Comprehensive 5G NR V2X Simulator for Unicast, Multicast, and Broadcast Communication Modes
(SLIIT, Faculty of Engineering, 2024-10) Dissanayaka, D.M.S.D.; Nethmini, K.G.M.; Dharmarathne, R.G.C.D.S.; Priyankara, W.N.B.A.G.
As the field of vehicular communication continues to evolve, the need for reliable and realistic simulation tools becomes increasingly critical. This paper introduces a novel 5G New Radio Vehicle to Everything (NR V2X) simulator, a state-of-the-art tool to emulate unicast, multicast, and broadcast communication modes. The simulator is built upon the well-established ns-3 network simulator and integrates seamlessly with the Simulation of Urban Mobility (SUMO) traffic simulator. This integration allows for the creation and analysis of complex vehicular communication scenarios, enhancing the realism and applicability of the simulations. One of the key features of our simulator is its flexible architecture. This flexibility enables it to accommodate a wide range of scenarios, making it a versatile tool for researchers and practitioners in vehicular communication. In addition to its technical capabilities, the simulator boasts a user-friendly interface. This interface enhances its accessibility, making it an easyto- use tool for researchers of all levels of expertise. We present an in-depth analysis of the performance of different communication modes under various scenarios. Key performance indicators such as average throughput, delay, and packet loss are evaluated, providing valuable insights into the intricacies of nextgeneration vehicular communication systems. Our work contributes significantly to the advancement of 5G NR V2X research. The simulator is a useful resource for exploring and understanding the complexities of vehicular communication systems, paving the way for future advancements in this exciting field. Our work will inspire further research and development in vehicular communication, bringing us one step closer to realizing the full potential of intelligent transportation systems.
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Battery-Less Sensor Node Design with Solar Panels and LoRa for Wireless Sensor Networks
(SLIIT, Faculty of Engineering, 2024-10) Premachandra, N.G.P.R; Edirisinghe, S
A wireless sensor network (WSN) is a network of sensors that detect physical changes and convert them into analog or digital signals. These sensors communicate with each other to monitor and collect data from a specific area. Applications of WSNs range from environmental monitoring to agriculture, industrial automation, etc. The current WSN nodes are powered by rechargeable batteries and designed for short distances. The problems faced with current WSNs are short-distance communication, battery replacement in large, deployed networks, and rechargeable batteries that take longer time periods to recharge. The term “battery-less” refers to devices that operate without traditional batteries or external power sources. In this design, solar energy is used as a sustainable energy source, and supercapacitors are used to store the solar energy. Supercapacitors have a greater number of charging-discharging cycles than batteries, which can operate in a wide temperature range. They are also more environmentally friendly than typical batteries. LoRa is the technology used for long-range communication, which operates in Industrial, Scientific, and Medical (ISM) radio bands, which is the most cost-effective technology that provides wide coverage with low power consumption. For power management, lowpower approach and sleep mode are used to make the sensor node work efficiently with the stored power in the supercapacitors. The whole system design was optimized, taking scalability, performance, and cost-effectiveness into account.
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Facile and feasible synthesis of ZnO Nanorods Using Microwave Irradiation and their Morphology Dependent on Capping Agents
(SLIIT, Faculty of Engineering, 2024-10) Sahajeewa, L. K. N. N.; Bandara, T. M. W. J.; Narangammana, L. K.; Bandara, K. M. S. P.
In the recent past zinc oxide (ZnO) has gained a lot of attention as a piezoelectric material. Its low cost, relative abundance, and ease of processing have made it a promising candidate to be used in various applications. In addition to its functional properties, its chemical stability and biocompatibility make ZnO suitable to be used in different environments. The synthesis of nanowires, nanorods, and other nano-structured morphologies of ZnO is highly important for the development of piezoelectric devices and solar cells. There are numerous methods for ZnO nanorod synthesis. The present research focused on the investigation of simple and low-cost synthesis methods of ZnO nanorods, namely microwave irradiation and usage of capping agents. According to the literature, the device performance improves with decreasing widths and increasing aspect ratios of ZnO nanorods. ZnO nanorods with desired size was obtained by chemical precipitation, using the readily available chemicals, ZnSO4 and NaOH, as precursor solutions; separately following microwave irradiation and the using appropriate capping agents, to control the size of the nanorods. The dependence of the size of the nanorods on the microwave cycle time intervals (15 s, 30 s and 60 s) was investigated, and a relative decrease in the size of the ZnO rods with larger cycle time intervals was observed utilizing scanning microscopic images. A width of ~177.0 nm and aspect ratio of ~6.7 was observed for the rods microwaved in 60 s cycle time intervals. The effect of starch, polyvinyl alcohol (PVA), and polyethylene glycol (PEG) was investigated as capping agents. Starch and PVA showed axial capping, increasing the width and decreasing the aspect ratio. PEG showed lateral capping, decreasing the width and increasing the aspect ratio; giving a width of ~182.4 nm and an aspect ratio of ~ 6.5. The XRD analysis of ZnO confirmed that the synthesized particles were in a Wurtzite phase. Hence, ZnO nanorods with the required wurtzite crystalline structure were synthesized in this research.
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Tactile Sustainability: Exploring Sensory Perception in Sustainable Building Design
(SLIIT, Faculty of Engineering, 2024-10) Kudaligama, A.; Udawattha, C.
The built environment plays a pivotal role in shaping human behavior, emotions and well-being. Our sensory system demonstrates remarkable sensitivity in perceiving the textures of building walls, even when visual cues are absent. However, while the importance of material texture in the architectural perception is widely acknowledged, there remains a lack of empirical evidence regarding the specific influence of these textures on perceived spaciousness. This research explores the intricate realm of sensory perception within sustainable building design, with a focus on tactile experiences with spaciousness and material selection. Blindfolded participants tactually explored a range of sustainable building materials, including recycled wall putty, bamboo composite board, and rammed earth, characterized by varying textural qualities, smooth finish, semi-rough finish and rough finish respectively. Subsequent experiments introduced thermal stimulation, further enhancing participants' perceptual judgments. Findings demonstrate participants' ability to accurately identify these materials based solely on tactile cues, showcasing a pronounced preference for natural and eco-friendly options. The implications of these findings suggest integrating tactile considerations into sustainable design practices, promoting low-impact materials that offer tactile satisfaction and more spaciousness. These findings advance biophilic design principles, fostering connections with nature through tactile elements inspired by sustainability. Ultimately, the research highlights the significant role of tactile perception in shaping perceptions of sustainability and informs design strategies that prioritize sensory comfort and spaciousness and environmental responsibility in the built environment. These insights contribute to the ongoing evolution of sustainable design practices in the built environment not only meets functional needs but also enhances human well-being and ecological stewardship.
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Steerable Directional Listening for Individuals with Unilateral Hearing Loss
(SLIIT, Faculty of Engineering, 2024-10) Wimalaratne, U.A; Seneviratne, L; Malasinghe, L
A novel hearing aid design which incorporates 3 separate phased arrays with a digital signal processor running an adaptive beamforming algorithm, Generalized Sidelobe Canceller (GSC), providing the user with the capability of effectively focusing their listening to a certain source while suppressing any masking interference sources. The proposed phased array achieved an array directivity of 7.93dB with a half power bandwidth of 35.20º. The GSC and the phased array designed, when simulated, was able to achieve a SINR improvement of 9.72dB under strong noise levels and a 2.55dB SINR improvement under low level noise which were located spatially close to the desired source.
Open Access
Keynote 02: Toward a Coordinated Effort to Focus Research to Fulfil Needs of The Energy Industry
(SLIIT, Faculty of Engineering, 2024-10) Siyambalapitiya, T
Development of the energy industry did not end when Sri Lanka declared 100% electrification in 2016. When the improved household woodstove was developed by a NGO in 1970s, further developed by the NERD Centre and promoted by Ceylon Electricity Bard (CEB), research into more efficient ways to use firewood did not end. Actually, that is where research has to begin, to make the expanded electricity network more efficient, technically and financially. Energy needs for industrial heating, provided cheap and used efficiently, is key to growth in manufacturing and competitive exports.
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ChemicalOxygen Demand Reduction of The Spent Wash Condensate by Applying Sugar Cane Bagasse Ash
(SLIIT, Faculty of Engineering, 2024-10) Lankathilake, L.J.M.U.; Wijesekara, E.R.J.M.D.D.P.; Amarasinghe, A.M.P.
Distillery spent wash is a highly acidic waste generated during ethanol production in sugar industries. It makes a challenging industrial wastewater, due to its high organic content and complexity and it needs to treat before being released into the environment. The spent wash can evaporate, creating a thick slurry and vaporized liquid. The slurry can be used for different applications such as a fertilizer production. This vaporized fraction can be condensed, and this research study focuses on applying a sustainable waste management approach to reduce the COD of spent wash condensate by using ash generated from bagasse combustion. Four experiments were included in the study. First, H2O2-treated and untreated fly ash and bottom ash from the bagasse combusted boiler were mixed with the spent wash condensate and filtered out to determine the most suitable ash type for COD reduction. Then, the chosen ash type was used in various ratios and retention times to determine the optimum operation conditions. Finally, the COD reduction capacity of the boiler ash was determined by treating condensate multiple times. The results indicated that the optimum COD reduction spent wash condensate to treated bagasse fly ash ratio is 1: 50 (W/V), and the optimum retention time is 02 hours. Furthermore, the treated bagasse fly ash can be used twice to treat the condensate of distillery spent wash, and if it wants to be reused more, it should retreat with H2O2. The average COD value of raw spent wash was around 130,000 – 160,000 mg/L range, and it has reduced to approximately 70,000 mg/L in the spent wash condensate. After ash treatments the COD of spent wash condensate can be reduced to approximately 30,000 mg/L. This method can reduce the spent wash COD by about 75%; additional treatment is required to reduce it to an environmentally disposable level.
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An Investigation on the Reliability of Pile Toe Defect Rectification Method used in Sri Lanka
(SLIIT, Faculty of Engineering, 2024-10) Hapugaswatte, M; Thilakarathne, T.M.D; Thilakasiri, H.S
The foundation is the vital part of any infrastructure as it will be the element that will eventually bear the superstructure load. In cases where the soil conditions are poor and structural loads are high, pile foundations are used more often. These piles should be defect free to not fail under the structural loads. So, the identification and rectification of such defects should be performed at early stages of construction. In this study, the reliability of the rectification method used for pile toe defect rectification in Sri Lanka (pile coring and grouting method) is studied. Raw data from 11 piles, found as defective through Cross-hole Sonic Logging (CSL) test, are analyzed. Six of these piles were retested after rectification using the same test while the remaining piles were retested using High Strain Dynamic (PDA) test. Out of the six piles, three showed an increase in the effective area, two still showed some defective areas and one was an incomplete test due to a blocked tube. Out of the five tested through PDA test, only one showed an acceptable β value, which is a parameter that represents the scale of the pile defects identified. Therefore, it was concluded that even though there is an overall improvement in the pile effective area, some defects could still exist within the pile that may require to be rectified and retested for integrity. It was also concluded that due to the comparatively lower accuracy of the PDA test, acceptance of a defective pile based only on this test without rectification is not acceptable. Future research suggestions were made to further refine the results of this research and to expand the scope to defects in other regions of the pile.
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Exploring Sri Lankan Sign Language (Slsl) and Its Role in Bridging Communication Barriers: A Review of Translation Tools and Techniques
(SLIIT, Faculty of Engineering, 2024-10) Wickramasinghe, B.M.G.S.T.S.K.; Punchimudiyanse, M.
Deaf-mute persons frequently struggle to communicate their views to the speaking population in society since their major form of communication is Sri Lankan Sign Language (SLSL). This occurs in schools, government buildings, marketplaces, the availability of medical services, and when people's socioeconomic demands are met. As of the first quarter of 2020, the number of deaf people in Sri Lanka who use sign language is estimated to be 107,000, or around 0.4% of the country's total population and 1.2% of the labour force overall. The majority of issues are caused by the lack of SLSL interpreters and expertise or the scarcity of digital translation tools in SLSL. The National Institute of Education Sri Lanka (NIESL) publishes a variety of books that are utilized in deaf schools all around the island to address these kinds of issues. Additionally, the Sri Lanka Central Federation for Deaf (SLCFD) has helped with the publication of sign books. However, there are still several problems that cause the underutilization of the deaf population as a productive workforce, due to lack of SLSL vocabulary and public ignorance. Deaf-mute communication has been the subject of several studies and prototype implementations over the last three to four decades all over the world. Additionally, recent developments in parallel processing have allowed researchers to enhance these deaf-mute solutions. However, the majority of SLSL research focuses on language issues, with a few studies in the technological field. A significant reason for the decreased contribution to this field of study is the complexity of SLSL. A two-way conversation between a hearing person and a deaf person is necessary for typical communication between the two groups of people. The communication between deaf and hearing people is the topic of this study. SLSL's conversational approach often uses a Sign for each Tamil or Sinhala word or sentence. A single posture, multiple postures, and multiple postures with a movement sequence are the foundations for SLSL indications.
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Experimental Investigation of Some Strength Parameter Correlation in Blended Cement Concrete
(SLIIT, Faculty of Engineering, 2024-10) Chularathna, P. K. G. O. T.; Somaratna, N.
Sri Lanka has adopted Eurocodes for structural designs. Accordingly, the design of concrete structures should adhere to EN1992 (Eurocode 2). The strength parameters of concrete essential for designs are classified in Eurocode 2 based on the compressive strength of concrete. Most of the other relevant strength parameters are derived using correlations with compressive strength. These correlations based on past empirical test results would typically be valid for concrete made using ordinary Portland cement (OPC). Recently there has been a tendency to use blended cements for concrete. To develop economical and safe designs in such cases the correlations among strength parameters used in EN 1992 should be verified as being applicable to blended cement concrete too. The study presented here was aimed at investigating the applicability of EN 1992 correlation between compressive strength and split cylinder tensile strength to blended cement concretes. Test specimens of concrete made using a blended cement – Portland Composite Cement (PCC) – were cast, cured, and tested under standard conditions for their compressive strength and split cylinder tensile strength. These tests were repeated for greater reliability. For comparison, similar tests were performed on concrete made using OPC also. The measured compressive strengths were used to produce estimated values of corresponding tensile strengths following the EN1992 correlations. Comparisons were made, in graphical form, between the measured tensile strengths and the estimated tensile strengths. Separately for each cement type. They revealed that the test results for OPC concrete, as expected, aligned with EN1992 correlations with a significant margin of safety while those related to blended cement, though complying with EN1992 correlations, provided only a narrow margin of safety. This indicates a need for a higher level of quality assurance for blended cement concrete. As these observations are based on a limited number of tests it is recommended to conduct further comprehensive studies.
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Development of DSSC Counter Electrode Using PEDOT: PSS/GO Nanocomposite
(SLIIT, Faculty of Engineering, 2024-10) Ravindran, N. S; Wijayarathne, W. M. K. B. N; Chandrika, R. P.; Medagedara, A. D. T.; Kumara, G. R. A; Bandara, T. M. W. J.
Dye-sensitized solar cells (DSSCs) have garnered considerable research interest owing to their ability to achieve high photo-to-electric energy conversion efficiencies at a relatively low production cost. While platinum has been recognized for its exceptional electrocatalytic performance and efficiency as a counter electrode in DSSCs, its higher cost and vulnerability to corrosion have prompted the exploration of alternative materials to replace Pt in this role. DSSCs have demonstrated noteworthy photovoltaic performances by employing a range of candidate materials, including conducting polymers, carbon materials, and nanocomposites of conducting polymers and carbon materials, as counter electrodes. The motivation to form composites or hybrids with nanomaterials stems from the aim to improve the overall photovoltaic efficiency in DSSCs. The main objective of this study was to fabricate a DSSC utilizing a counter electrode comprised of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and graphene oxide (PEDOT: PSS/GO). The fabrication of the counter electrode involved depositing the PEDOT: PSS/GO nanocomposite onto a graphite sheet using drop casting. The GO, which was synthesized through a modified version of Hummer’s method, underwent characterization via Raman spectroscopy and XRD analysis to ensure a successful synthesis process. The surface morphology and the Raman spectra of coated nanocomposites indicated the good dispersion of GO and the strong interaction between GO and the PSS chain, respectively. In the fabrication process of the DSSC, a gel polymer electrolyte was incorporated between a five-layer TiO2-based photoanode and the PEDOT: PSS/GO-based counter electrode. Photovoltaic performances of DSSCs were evaluated under simulated solar irradiance of 1000 W m-2. They were able to achieve a power conversion efficiency of 2.7%, Voc of 0.73 mV, Jsc of 5.21 mA cm-2, and a fill factor of 0.71.
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Reduction of Carbon Dioxide Emission from the Use Phase of Electric Vehicles in Thailand
(SLIIT, Faculty of Engineering, 2024-10) Chinda, T
Electric vehicle is a solution to reduce global warming, carbon dioxide (CO2) emission, and environmental impact and achieve sustainable development goals. The Thai government planned that 30% of new vehicles produced in Thailand in 2030 would be zero-emission vehicles. With various government support, the number of EVs is expected to increase in the next few years abruptly. With an increased use of EVs, it is expected that the CO2 emission will be reduced. This study develops a system dynamics (SD) model utilizing an SD modelling approach to predict the number of EVs and examine the reduction of CO2 emissions from EVs in the use phase. It focuses on dynamic relationships between variables and is associated with the time-dependent behaviour of controlled systems. The simulation results show a CO2 emission reduction of 15.37 million tonnes in 2030. With continuous promotion of EVs, the amount of CO2 emission reduction is expected to be 37.29 million tonnes in 2036. The sensitivity analysis results reveal that by changing the driving distance from the minimum to maximum distances, only the magnitude of the model changes, while the model behaviour remains the same. This confirms the validity of the developed SD model. It is found that by maximizing the driving distance by 33%, the CO2 emission is further reduced by almost 50%. Moreover, when the government support period is changed to four years, the CO2 emission reduction becomes 19.73 million tonnes, reaching the government target of a 30% reduction in 2030. The Thai government may use the study results to plan for supporting policies to enhance the demand for EVs and achieve the SDGs in the long term. Different policies may be tested to select suitable policies for implementation. Countries with similar EV market statuses may adjust the study results to suit their implementation.
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Impact of Pandemic on Finances of SMEs in Sri Lankan Construction Industry
(SLIIT, Faculty of Engineering, 2024-10) Abeysiria, O; Allis, C; Lokuge, A
This study focuses on the impact of the pandemic on the financial aspects of Sri Lankan construction SMEs. The pandemic has significantly affected economies globally. Sri Lanka, a country whose economy mainly consists of SMEs, has faced adverse effects due to the preventive measures implemented to control the spread of the disease. Nearly 90% of registered construction firms in Sri Lanka belong to the SME category. Financial challenges or difficulties were encountered by construction SMEs even before the pandemic impacted Sri Lanka. Currently, most of the Sri Lankan construction SMEs are on the brink of bankruptcy, mainly due to the financial challenges brought about by the pandemic. This study comprises primary data produced from semi-structured interviews and secondary sources of data from the literature review. It has identified the financial challenges undergone by construction SMEs in usual manners, including limited access to bank credit facilities, lack of capital of the contractor, and lack of cash flow due to delayed payments, among others. Principally, there were several financial challenges created due to the pandemic, including barriers in obtaining credit facilities from suppliers, and the challenges that were usually present have intensified with the effects of the ongoing pandemic. In the latter part of this study, strategies that Sri Lankan construction SMEs have executed to survive in the industry are pointed out. Most SME contractors in Sri Lanka do not have positive perspectives on staying in the industry for the long term, given the financial challenges they have encountered with the current pandemic.