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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Publication Open Access Intelligent Reflecting Surface for 6G Wireless Communication(SLIIT, Faculty of Engineering, 2025-02) Malshan, K. A. T. I.; Iddamalgoda, G. D. D.; Rajendran, H.; Aashiq, M. N. A.; Haleem, M. A. L. A.In the context of future 6G wireless communication, addressing challenges related to non-line-ofsight communication is paramount. This paper presents the design and prototyping of Intelligent Reflecting Surfaces (IRS) as a solution to provide wireless connectivity in the absence of Line-of-Sight (LoS) propagation paths for effective wireless communication. We simulated phase-shifter unit cell structures of IRS utilizing CST Studio software suite. A prototype IRS consisting of a two-dimensional array of unit cells was designed and built. Our tests on the prototype revealed the effectiveness of the design exhibiting a remarkable 315o of dynamic range in phase shift performance at 2.4 GHz. The losses introduced by the IRS in reflecting an incident signal were brought down to an acceptable limit via an iterative design and simulation process. Measurements on phase shifting properties were performed using a low-cost Vector Network Analyzer (VNA). A comparative study was carried out on the simulation and experimental outcomes and good agreement was found confirming the effectiveness of the prototype IRS.Publication Open Access Material Wastage on Cost Overrun in Construction Projects: An Impact Study Carried Out in Sri Lanka(SLIIT, Faculty of Engineering, 2025-02) Kothalawala, N.T.B.; Malkanthi, S.N.; Dharmaratne, P.D.Cost overruns are a prevalent issue in construction industry, and material wastage is recognized as one of the key contributory factors of it. Against that background, this research investigates the impact of material wastage on cost overruns in construction projects experienced in Sri Lanka. It strives to achieve the objective of providing insights into the relationship between material wastage and cost overruns and identifying potential strategies to mitigate its impact. The research methodology developed in this concern involves a comprehensive literature review to establish a theoretical premise of material wastage and cost overruns in construction projects. The data about the issue was collected through surveys, interviews, and site inspections of a series of ongoing and completed construction projects in Sri Lanka. Later, the data was analyzed statistically to determine the extent of material wastage and its impact on cost overruns. The findings achieved thereby reveal a significant correlation between material wastage and cost overruns in construction projects in Sri Lanka, highlighting that inefficient project planning, inadequate supervision, lack of skilled labour, and ineffective procurement practices contribute to material wastage, which ultimately leads to cost overruns. The financial implications of this situation are substantial and affect project budgets and profitability. Based on the research findings, the paper strives to make recommendations for strategies to mitigate material wastage and reduce cost overruns in construction projects. These include improved project planning and scheduling, enhanced supervision and training, effective procurement and inventory management, and adoption of sustainable construction practices.Publication Open Access Linearization of Nonlinear Components in Instruments(SLIIT, Faculty of Engineering, 2025-02) de Silva, Clarence W.Real instruments, devices, and components are found to be nonlinear and are represented by nonlinear analytical models. Accordingly, linear systems (or models) have idealized representations. However, it is realized far more convenient to analyze, simulate, design, and implement nonlinear devices through the use of linear models. Also, regarding some devices, the degree of nonlinearity may not be significant. In such cases, nonlinear devices are often “approximated” by linear models. Against that background, this paper explores several important methods of linearization of nonlinear physical devices with practical examples.Publication Open Access Rice Husk Derived Biomass Briquettes for Boilers: Ingredient-Based Product Quality Study(SLIIT, Faculty of Engineering, 2025-02) Lakshika, H.N.M.; Arachchige, U. S.P.R; Koliyabandara, P.AThis research investigates the feasibility of repurposing rice husk waste into sustainable biomass briquettes, addressing environmental and economic challenges associated with conventional biomass sources in Sri Lanka. The study involves a comprehensive analysis of rice husk utilization, focusing on three size fractions: original size, particles less than 5mm, and powder form. Rice husks less than 5mm was observed to have a composition of optimal fixed carbon content (11.63% ± 0.215), moisture content (10.53% ± 0.013), volatile matter (80.72% ± 0.005), and ash content (7.65% ± 0.004). The binding agents, namely starch, dummala tree resin, and wastepaper pulp, were used for briquette production. The optimal compositions for briquettes made with rice husk particles less than 5mm were determined as follows: rice husk with starch (1:6), rice husk with tree resin (1:7), and rice husk with wastepaper pulp (1:5). The calorific values of these optimum briquettes were found to be 15.446 MJ/kg for starch-based briquettes, 15.278 MJ/kg for paper pulp-based briquettes, and 15.323 MJ/kg for tree resin-based briquettes. In addition, briquettes made with an equal ratio (1:1) of binders showed calorific values of 14.175 MJ/kg for starch, 14.227 MJ/kg for paper pulp, and 15.275 MJ/kg for tree resin, with tree resinbased briquettes exhibiting the highest calorific value. In the product quality evaluation study carried out with these results, the proximate and ultimate analyses were conducted to characterize the briquettes and the thermogravimetric analysis (TGA) was conducted to characterize the rice husk and to examine the physical properties of the produced briquettes. The findings indicate that repurposing rice husk waste with various binding agents offers a sustainable solution for biomass fuel production. Accordingly, natural tree resin briquettes exhibited the highest density, compression ratio, and shatter resistance. These results suggest that utilizing natural tree resin can effectively address waste management challenges and create an environmentally friendly and economically viable industrial sector in Sri Lanka.Publication Open Access Correlation of tensile strength of blended cement concrete with specimen dimensions and aggregate size: A practical test review(SLIIT, Faculty of Engineering, 2025-02) Amarasinghe, N; Somaratna, NTest specimen dimensions affect most strength properties of concrete. The existing empirical relationships in this regard are predominantly based on concrete samples made by using Ordinary Portland cement (OPC). An important recent trend in Sri Lanka has been the increasing use of blended cements. This makes it necessary to examine whether the relationships hold for blended cements as well. In this study, split cylinder tensile strength tests were conducted to determine whether the specimen size and the tensile strength of concrete prepared using a blended cement (Portland Composite Cement (PCC)) display relationships similar to OPC. Tests were conducted on specimens using two cement types – OPC and PCC - and three concrete mix ratios and a range of specimen dimensions to study the effect of the specimen length (L), diameter (D), and aggregate size (a) on the split cylinder tensile strength (T). The data was examined using dimensional analysis based on Buckingham's π theorem. A slight increasing trend was observed in the ratio of split cylinder tensile strength to mean a compressive strength (T/fc,mean) with an increasing L/D ratio. As for the ratio of the aggregate size to the specimen diameter (a/D), the analysis showed an increasing trend in T/fc,mean values with an increasing a/D ratio, indicating a significant correlation between T/fc,mean and a/D. A nonlinear regression analysis was used in an attempt to determine a functional relationship among the non-dimensional parameters T/fc,mean, L/D, and a/D. But the differences in the derived relationships for different concrete mixes were too large for reaching a common relationship. Perhaps this was due to the small number of data points available. It was seen that relationships established for OPC may hold true for PCC too. However, the data used was limited in range and more comprehensive further tests should be conducted to confirm these findings.Publication Open Access Use of pine needles for producing high-calorific value bio-briquettes and pine resin for biomass boiler(SLIIT, Faculty of Engineering, 2025-02) Tharukarathne, P.W.T.M.C; Arachchige, U. S.P.R.; Koliyabandara, P. ABiomass, ranked as the fourth-largest energy source globally, presents a viable renewable energy option. However, inherent limitations such as low density and calorific value necessitate the development of quality-enhanced biomass, like biomass briquettes, for more efficient energy production. This study focuses on biomass briquette production using pine needles, abundant in the hilly regions of Sri Lanka, as a forestry waste-to-energy concept. The research aims to investigate the physicochemical properties of pine needles char for biomass briquette preparation and utilizing pine resin as a binding agent. Thermal degradation analysis, XRD tests, and physical property assessments were performed on raw materials and briquettes. The objectives include pine resin extraction and analysis of pine needles' properties, optimization of briquette composition to ensure high combustion efficiency and comparison of briquette properties with standards relevant to biomass. Results revealed that pine needle char possesses favorable characteristics for briquetting, with a moisture content of 6.105% and ash content of 4.233%. The 5:1 ratio briquette showed the best performance with a calorific value of 22.19 MJ/kg, a high density of 917.272 kg/m³, and a compression ratio of 3.507. Pine needle briquettes (PNB) were made with different ratio pine needles char and binder using a small-scale hydraulic press (2 tons; 5.5 MPa) with a honeycomb-type mold. The machine's estimated production capacity is 192 briquettes per day. The research results help to create inventive waste management solutions by transforming pine needles into valuable energy sources, benefiting the environment, industries, and self-employed individuals equally.Publication Open Access Enhancing Load Frequency Control in Interconnected Power Systems with Zone-Specific Fuzzy Controllers: Principles and Methods(SLIIT Faculty of Engineering, 2025-02) Jahangiri, S; Jones, K.OThis work focuses on load frequency control in interconnected power systems, a critical aspect of modern power grid operations. However, sudden load disturbances and generator outages can lead to transient oscillations between control areas, posing challenges to frequency control. The aim of the work was to investigate and enhance load frequency control behaviour, considering dynamic load changes and uncertainties. Fuzzy Logic Controllers optimized with Particle Swarm Optimization were applied to improve control robustness. The Particle Swarm Optimisation algorithm was used to tune the scaling factors and parameters of the fuzzy controllers to optimize their performance. The methods were tested on a standard four-area interconnected power system model equipped with load frequency control blocks, reheaters, governors, rate constraints, and thermal components. Different disturbance scenarios including parameter fluctuations and load changes were evaluated. The Fuzzy Logic Controllers demonstrate resilient response across scenarios without needing extensive tuning. Particle Swarm Optimization improves robustness through systematic exploration for constraint-based nonlinear optimization. Tuning fuzzy controllers with bio-inspired algorithms enhances efficiency in addressing complex grid conditions. The results provide insights into designing more secure and resilient grid controls, contributing to power system stability research.Publication Open Access Optimizing the Financial Risk Management Strategies in Water Supply Projects in Sri Lanka(SLIIT, Faculty of Engineering, 2025-01) Senanayake, U. S; Wijesinghe, T.; Perera, B. K. C.; Jayasinghe, Y. M.Infrastructure construction projects are considered highly susceptible to risks and uncertainties due to their complicated designs, sizes, functions and structural complexities. Among the different types of risks, the financial risks and the ability to manage them will have great implications for the cost performance of the relevant infrastructure projects. Therefore, high attention is paid to the financial risk management aspect of public infrastructure projects. In that concern, water supply infrastructure projects share several characteristics in common with other infrastructure construction projects while holding several other characteristics unique to themselves. Although many studies have been conducted on financial risk management in building and infrastructure projects, observed scanty of studies that address the financial risk management aspects of water supply projects in the Sri Lankan context. Therefore, this study is meant to fill significant void in terms of developing a financial risk management framework to address financial risk factors in Sri Lankan water supply projects. In carrying out this study, a mixed methodology was followed under an exploratory sequential design. Accordingly, the risk factors and risk management strategies identified in the reference literature were screened and shortlisted for their applicability in designing water supply projects in Sri Lanka and were validated through findings achieved at interviews with experts capable of highlighting new risk financial factors and strategies unique to the water supply projects in Sri Lanka. Subsequently, the risk factors and strategies identified in this process are mapped to develop a financial risk management framework for implementation of water supply projects in Sri Lanka in the future.Publication Open Access Use of Ascorbic Acid Linker in Enhancing the Photovoltaic Performance of CdS/TiO2 Quantum Dot Sensitized Solar Cells(SLIIT, Faculty of Engineering, 2025-01) Ajward, N.F.; Davisan, S.; Perera, V.P.S.This study explores the use of ascorbic acid to enhance the photovoltaic performance of CdS/TiO2 Quantum Dot Sensitized Solar Cells (QDSSCs). Ascorbic acid acts as a mild reducing agent, donating electrons to Ti atoms on the TiO2 film, effectively filling oxygen vacancies known to act as recombination centers for photogenerated charge carriers. By passivating these detrimental sites, ascorbic acid facilitates improved carrier transport and reduces recombination, ultimately boosting photocurrent and overall efficiency. QDSSCs fabricated via the Successive Ionic Layer Adsorption and Reaction (SILAR) method were characterized using I-V measurements, Incident Photon to Current Conversion Efficiency (IPCE), Impedance Spectroscopy (IS), and overall power conversion efficiency. The optimized cell incorporated with ascorbic acid demonstrated a remarkable improvement compared to the control, achieving a short circuit current density (Jsc) of 4.863 mA/cm², open circuit voltage (Voc) of 446.1mV, efficiency of 1.368%, fill factor of 24.6%, and maximum power of 0.342mW. Optimization of ascorbic acid absorption time and precursor concentrations resulted an impressive 68.26% enhancement in efficiency (from 0.813% to 1.368%) and increase in maximum power from 0.163 mW to 0.342 mW for 0.64 cm². cell. This study highlights the potential of ascorbic acid as a simple and effective strategy for enhancing the performance of CdS/TiO2 QDSSCs, paving the way for further developments in low-cost and efficient solar cell technologies.Publication Open Access Advancing Audio Surveillance in Simulated Environments: Real-World Soundscapes and Targeted Noise Detection through Enhanced Beamforming Techniques(SLIIT, Faculty of Engineering, 2025-01) Stroud, S; Jones, K; Edwards, G; Robinson, C; Chandler-Crnigoj, S; Ellis, DThis paper introduces an innovative beamforming approach designed for audio surveillance, executed through a virtual simulation of a real-world environment based at Liverpool John Moores University. Our research is driven by the increasing requirement for sophisticated audio analysis methods to isolate and enhance specific sounds within noisy environments for forensic analysis, for example, in criminal court cases. By leveraging a time-delay beamforming algorithm, our work offers a novel solution to discern and amplify targeted noises amidst complex soundscapes, a challenge commonly encountered in urban surveillance and forensic audio analysis. Our approach's foundation lies in utilising a carefully arranged, robust array of omnidirectional microphones, which are instrumental in capturing a wide range of real-world sound signals. The core of our methodology involves processing captured sounds using the proposed algorithm, followed by evaluating the system's effectiveness in capturing the desired localised audio sources. This paper explores the system's resilience against microphone array degradation, showcasing its robustness in scenarios of partial system functionality. The experiments, grounded in the simulation of real-world acoustic environments, demonstrate the algorithm's adeptness at managing sound reflections and reverberation, critical factors in the realistic replication of urban soundscapes. It also considers the broader implications of our findings, exploring the potential for adopting this technology in various domains beyond law enforcement, including broadcast solutions, advanced audio engineering applications, and animal conservation in the wild. In conclusion, this research showcases a creative approach to audio surveillance and opens the door to numerous applications that can benefit from enhanced methods of audio isolation and analysis. Our findings contribute to the ongoing discourse on developing advanced surveillance technologies, offering insights that could help shape the future of audio processing and analysis.