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

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

Browse

Now showing 1 - 20 of 43

Embargo
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.
Embargo
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.
Embargo
Design Environments Inspiring Employee Satisfaction: A Comprehensive Study on Design Elements Rousing Satisfaction Levels with Special Reference To State Sector Offices in Homagama, Sri Lanka
(SLIIT, Faculty of Engineering, 2024-10) Pathirana, V.D.; Wijesundara, J
Though job satisfaction is one of the most studied facets of organizational behaviour, the involvement between its physical environment and satisfaction for work efficiency is seldom studied. A quality design fosters a less stressful and productive office environment. The employable community has proliferated with the development of the tech city in Homagama. Thus, a healthy office environment is essential for employees' eight-hour daily work duration. This paper aims to study how employees determine their satisfaction level within the work environment regarding different design elements. It investigates the extent of integration of identified design elements and discusses further necessary improvements. The research involved 84 employees across three state-sector offices in Homagama: the Divisional Secretariat Office, the Zonal Education Department, and the Medical Officer of Health. The examination will utilize on-site observation, an open-ended structured questionnaire and available literature. The perceived importance of different parameters will be clarified with the compatibility of the standard parameters of British standards. The results highlight a significant impact on employee satisfaction due to the lack of personal space, with additional factors including internal layout, furniture, circulation space, ventilation levels, and sanitary facilities. Furthermore, the study indicates that the perceived importance of design parameters equals or higher than the importance of satisfaction. In conclusion, prioritizing employee health and well-being in office spaces is crucial for improving overall well-being, efficiency, and reducing energy consumption. The paper suggested enhancing office design through the implementation of passive design principles and space utilization strategies. The insights will be useful for architects and facility managers to utilize the interior by improving the quality of productive, user-friendly, energy-efficient, and sustainable offices.
Embargo
Computing Awareness and Computational Thinking in Sri Lankan Street Vendor Communities: A Pilot Study
(SLIIT, Faculty of Engineering, 2024-10) Perera, S.A.K.M; Munasinghe, B.
Although street market is a common and diverse form of informal economy in a country, the computing awareness and computational capacity of its contributing communities are largely understudied. This case study attempts to investigate the Computing awareness and Computational Thinking (CT) skills among street vendors in a Sri Lankan urban commercial area, using a mixed methods approach. It summarizes interviews, survey and observational findings about their digital literacy, digital awareness, problem solving skills and algorithmic thinking ability and the results are interpreted to understand their Computing awareness and CT skills. The findings reveal that Sri Lankan urban street vendors use digital devices, especially smartphones, for various purposes related to their vending activities, yet face concerns and challenges in accessing, affording, and trusting digital technologies. They seem to apply algorithmic thinking in planning, organizing, and optimizing their vending operations, and display problem-solving skills in coping with uncertainties, risks, and conflicts in their work environment, reflecting their resilience and adaptability. The study confirms that CT could be a valuable and relevant skill for street vendors and recognizing and nurturing these skills can enhance their socio-economic inclusion and resilience. The study also provides indicators for future research, such as exploring the gender and generational differences in both Computer awareness and Computational Thinking skills and evaluating the impact of educational interventions in those areas.
Embargo
Enhanced Lightweight Visual Cryptosystem (ELVC): Fortifying Cybersecurity for Visual Data Protection
(SLIIT, Faculty of Engineering, 2024-10) Bhuvaneshwari, A. J; Kaythry, P.
Within the field of cybersecurity, protecting visual data poses significant difficulties because of its extensive use and vulnerability to unwanted access. This article introduces the Enhanced Lightweight Visual Cryptosystem (ELVC), which is intended to strengthen cybersecurity by efficiently encrypting visual data. Using the Blake2 hash algorithm and advanced encryption techniques, the ELVC encrypts AC and DC coefficients, which are critical components in visual data compression. The encryption algorithm improves data security by calculating entropy, histograms, and PSNR values. Rigorous NIST performance tests demonstrate the ELVC's resilience to cryptographic weaknesses, ensuring its effectiveness in preventing cyber-attacks. The ELVC, which emphasizes both security and efficiency, is well-suited for deployment in resource-constrained situations like mobile and IoT devices. With its ability to protect visual data while maintaining quick processing, the ELVC stands as a noteworthy advancement in cybersecurity, offering heightened resilience against evolving threats.
Embargo
Exploring The Factors Influencing Delays in Road and Building Projects in Sri Lanka
(SLIIT, Faculty of Engineering, 2024-10) Abeywardhana, S.S; Jeewandarage, P.M
The Sri Lankan road and building construction industry currently grapples with significant time overruns compared to the planned schedules. Project delays pose substantial challenges for contractors, consultants, and clients alike. This research aims to identify the key factors contributing to delays in the construction of buildings and roads. A thorough literature review revealed 48 primary causes of construction delays. A questionnaire survey was conducted, incorporating these 48 delay factors and categorizing them into four major groups: contractor related, client-related, consultant-related, and external factors. Responses were gathered from 160 professionals using the convenience sampling method and were subsequently analyzed using the Relative Importance Index (RII) for ranking. The results highlight several critical factors responsible for construction delays in Sri Lanka. These include delays in payment progression, financial difficulties and economic challenges faced by clients, lack of proper planning and scheduling, difficulties in project financing by contractors, mistakes and discrepancies in contracts, slow implementation of inspections and testing by consultants, and changes in government policies and leadership. Additionally, interference by political leaders from external parties emerged as a significant factor contributing to delays. The implications of these findings underscore the need for realigning project management strategies to mitigate delays in road and building construction projects in Sri Lanka. This paper not only identifies key factors but also offers recommendations to minimize the impact of delays on construction projects in the country. These insights are crucial for enhancing the efficiency of project management in the Sri Lankan construction industry.
Embargo
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.
Embargo
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.
Embargo
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.
Embargo
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.
Embargo
Correlation of compressive strength and flexural tensile strength of blended cement concrete
(SLIIT, Faculty of Engineering, 2024-10) Kulathilaka, U. G. D. U.; Somaratna, N.
Eurocodes for structural designs have been adopted for Sri Lanka. Hence in Sri Lanka, concrete designs need to be in compliance with the relevant Eurocodes – mainly EN1992 (EC2). In EC2, concrete is categorized by its compressive strength. The other strength parameters are derived from the compressive strength using correlations based on empirical data. A recent trend has been the increasing use of blended cement for concrete in certain applications. But the correlations specified in EC2 are based on data probably related to Ordinary Portland Cement (OPC) concrete. It is important to examine whether the correlations listed in EC2 are applicable to blended cement concrete too. The present study was performed to experimentally examine the correlation of compressive strength and flexural tensile strength of blended cement concrete. A parallel study was conducted for OPC concrete to serve as a baseline reference. Standard beam and cylinder specimens of concrete were cast, cured, and tested for flexural tensile strength and compressive strength. Three different mix ratios were used. Each mix was tested twice. The same series of tests were conducted for blended cement (Portland Composite Cement – PCC) and for OPC. Experimentally measured values of flexural tensile strength were compared against their estimated values derived from the experimentally measured compressive strengths, using EC2 listed relationships. The analysis showed that in the case of both OPC as well as PCC, the measured values of the flexural tensile strength exceeded their estimated values based on EC2 relationships. But the testing conducted has been limited in the number of tests performed, the range of mix ratios, and the types of aggregate used. In order to affirm the general applicability of Eurocode 2 relationships for blended cement concrete also, additional more comprehensive testing is warranted across a wider span of mix ratios and aggregate types.
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.
Embargo
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.
Embargo
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.
Embargo
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.
Embargo
Efficiency Enhanced by Chelation of Al3+ Metal Ions with Erythrina Fusca Flower Dye Harnessing Bathochromic Shift
(SLIIT, Faculty of Engineering, 2024-10) Mannawadu, M.W.M.K; Perera, V.P.S.
Utilization of natural dyes in dye-sensitized solar cells (DSSCs) presents a sustainable approach towards enhancing photovoltaic efficiency. This study explores the bathochromic shift exhibited by Erythrina fusca (Erabodu) flower dye upon chelation with Al3+ ions, offering an innovative strategy for improving DSSC performance. 20g of chopped flower petals was boiled with 50ml of ethanol until flower petals become pale in colour in the dye extraction process. After that, 0.1 M, AlCl3 solution was added dropwise to 2ml of dye solution until the colour changed to purple. The pH value of Erabadu bare dye was recorded as 5.47 and with the Al3+ ion addition it was changed to 4.49. Through spectroscopic analysis and electrochemical characterization, the chelation mechanism and its impact on dye absorption spectra and electron transfer dynamics was elucidated. The Dye was coated on a thin film of TiO2 nanoparticles deposited on fluorine-doped tin oxide (FTO) glass plates. FTO glass which coated with platinum was used as the counter electrode and iodin/triiodide (I2 / I3 -) was used as the electrolyte. Solar cell was tested with a light source with an intensity of 100 mW/cm2. Al3+ ion chelated Erabadu dye exhibited higher efficiencies than bare dye which was 1.627%. The open circuit voltage (Voc) of this cell was 470mV, short circuit current density (Jsc) was 4.00 mA/cm2 and the fill factor of DSSC’s was 0.553. The Incident Photon to Current Conversion Efficiency (IPCE) of the cell further revealed the action spectrum was broadened between 300 nm – 500 nm enhancing the efficiency. Our findings unveil the potential of Al3+ ion chelated Erythrina fusca dye as a promising sensitizer for DSSCs, paving the way for eco-friendly and efficient solar energy conversion.
Open Access
Keynote 01: Forensics - A New Direction for Engineering Education
(SLIIT, Faculty of Engineering, 2024-10) Jones, Karl O.
The number of students wishing to study engineering topics at University is on the decline, thus engineering departments need to consider ways of making engineering more attractive and hence increase student recruitment. While there are many approaches that could be taken, one that we have found has some merit is to include engineering forensics within the curriculum, or even as a complete programme.
Embargo
Analysis of Efficiency and TheAdsorptionNature ofMalachiteGreenDye fromanAqueous Solution on activatedCarbonGenerated fromStrychnos potatorum(Ingini) seeds
(SLIIT, Faculty of Engineering, 2024-10) Buthpitiya, B.L.S.K.; Yohan, L. N.; Arachchige, M
Malachite green (MG) is a basic dye with an amino group which is water soluble. This is a higher brilliance dye even in low concentrations. Therefore, MG is used mainly in dyeing for wool, leather, cotton, paper, wood, jute and as an anti-bacterial, anti-fungal, and anti-parasitical agent in aquaculture. The releasing of wastewater with MG from various industries is a huge problem because of the existence of MG in the wastewater causes toxicity for aquatic lives and it enters into the trophic levels of the food chains and causes teratogenic, mutagenic, carcinogenic and tumor-enhancing effects on human beings. Therefore, the major concern of this study is the removal of MG dye from an aqueous solution on activated carbon generated from Strychnos potatorum (Ingini) seeds (ACSP). The ACSP was characterized by Scanning electron microscope (SEM). The batch adsorption studies were conducted to determine the effect of adsorbent dosage, initial MG concentration, contact time and temperature on the removal of MG. The efficiency of the dye adsorption was determined by Pseudo-first order and Pseudo-second order kinetic models. The adsorption nature was determined by the thermodynamic study. According to the results of this study, the maximum removal percentage of MG dye (99.67%) was obtained for 0.20 g of adsorbent per 25.00 mL of MG volume, pH 4, 30 0C, 60 mg L-1 of initial MG concentration and 2 h contact time and Pseudo-second order kinetic model was well fitted to the data. The negative value for the Gibbs free energy change showed the spontaneity and feasibility of this adsorption process.
Embargo
Comparative Analysis of Characteristics of Dye-Sensitized Solar Cells Utilizing Extracts of Young vs Mature Leaves of Elaeocarpus Serratus as Natural Sensitizers
(SLIIT, Faculty of Engineering, 2024-10) Davisan, S.; Nupearachchi, C.N.; Perera, V. P. S.
This study addresses the pressing global need for sustainable energy sources by exploring dyesensitized solar cells (DSSCs) as a viable alternative. Specifically, the research focuses on extracting natural pigments from Elaeocarpus serratus (Sri Lankan olive) leaves to enhance the efficiency of DSSCs. These leaves undergo color changes as they mature, presenting opportunities to extract different types of pigments at different ages. Extraction involves boiling pieces of leaves in absolute ethanol to obtain the desired pigments. Further characterization via UV-visible spectroscopy revealed the presence of different absorption bands of pigments in the natural dyes’ extracts. The constructed DSSCs employed these natural dyes, coated on TiO2 films deposited on FTO glass plates as the photoanodes. The liquid electrolyte was I2/I3 - and a platinum-sputtered glass plate served as the counter electrode. Photovoltaic characteristics were evaluated using a computerized PK-IV 100 I-V analyzer under 100 W/m2 illumination. Results indicated the superior performance of DSSCs utilizing young leaf extracts, yielding a short circuit current density (JSC) of 3.950 mA/cm2, open circuit voltage (VOC) of 458.8 mV, and a fill factor (ff) of approximately 0.553 with an efficiency (η) of 1.003%. Conversely, DSSCs utilizing. Mature green leaf extracts exhibited lower performance metrics, with JSC of 2.379 mA/cm2, VOC of 477.5 mV, ff around 0.492, and η of 0.559%. Therefore, the efficiency of DSSC fabricated with young leaf is 56% higher than the DSSC made with mature green leaf extract.
Embargo
Performance Improvement of Crossflow Air Turbines for Wave Energy Conversion in Oscillating Water Columns: A CFD Study
(SLIIT, Faculty of Engineering, 2024-10) Baddegamage, B.H.B.P.D.; Lee, Young-Ho; Gunawardane, S.D.G.S.P.; Yoon, M
The coastal countries have a valuable renewable energy source in the form of ocean waves, which, if harnessed effectively using wave energy converters (WEC), could significantly enhance their electrical energy supply. Numerous technologies have been researched, put forth, examined, and sometimes tested in real ocean conditions at full scale. One of the most promising WECs is the oscillating water column (OWC), which has a modest number of moving parts that are all above the water level with a relatively simple mechanism. Although the Wells turbine is a widely used power takeoff (PTO) system of OWC, having higher peak efficiency than the crossflow air turbine (CFAT), it shows a narrow operational flow range. This operational flow range issue could be addressed by deploying CFATs. Only a few researches have been conducted on the CFAT as the PTO for OWCs. The present study focuses on numerical model-building and validation using the available experimental data to investigate the performance characteristics for optimized nozzle shapes for CFAT. For the base model, numerical results are compared to experimental data for validation. The geometry of the nozzle is optimized to achieve maximum efficiency under steady-state conditions. The nozzle entry arc angle is varied between 90° to 150°. The optimized model reached a peak efficiency of 68% with a steady high efficiency for broader operating conditions (broader flow range). Therefore, the proposed design addresses the issue of the narrow band of the Wells turbine while potentially improving the efficiency of the existing CFAT model.