Journal Issue:
Journal of Advances in Engineering and Technology (JAET)

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Volume

Volume 03

Number

Issue ii

Issue Date

2025-02

Journal Title

Journal ISSN

2950-7138

Journal Volume

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Journal Volume

Articles

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PublicationOpen 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.
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PublicationOpen 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.A
This 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.
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PublicationOpen 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, N
Test 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.

Description

Editor-in-Chief Professor Rahula Attalage Editorial Committee Dr. Nandika Miguntenna Dr. Lakmini Malasinghe Dr. Priyantha Bandara Dr. Mudith Karunarathna Ms. Priyanwada De Silva Advisory Board Prof. Dilanthi Amarathunga University of Huddersfield, UK Prof. Janaka Ekanayake University of Peradeniya, Sri Lanka Prof. Kyaw Thu Kyushu University, Japan Prof. Jagath Manatunge, University of Moratuwa, Sri Lanka Prof. George Mann Memorial University of Newfoundland, Canada Prof. Srinath Perera, Western Sydney University, Australia Prof. Ahmed Abu–Siada Curtin University, Australia Prof. R. Thevamaran, University of Wisconsin, Madison, USA Prof. S. C. Wirasinghe University of Calgary, Canada Editorial Assistant / Secretary of the Journal Ms. Priyanwada De Silva

Keywords

Load Frequency Control, Interconnected Power Systems, Fuzzy Controllers, Zone-Specific Control, Pine Needles, Bio-Briquettes, Biomass Boiler, Tensile Strength, Blended Cement Concrete, Specimen Dimensions, Aggregate Size, Rice Husk, Biomass Briquettes, Product Quality, Linearization, Nonlinear Components, Instruments, Material Wastage, Cost Overrun, Construction Projects, Sri Lanka, Intelligent Reflecting Surface, 6G Wireless Communication