Sri Lankan Journal of Applied Sciences

Conversion of Waste Plastics into Hydrocarbon Fuel - Analysis of Combustion Behavior and Emission Characteristics of Waste Plastics Derived Fuel Blended with Diesel in an IC Engine: A Sustainable Approach for Waste Plastic Recycling

2025-07-30T20:52:09+0530

Plastics Waste has become a severe environmental challenge in the world. Currently practicing techniques like open dumping, land filling, incineration for plastic waste recycling are haphazardous, and causing significant negative impacts on the environment and human health. Waste plastics can be converted into hydrocarbon fuel by the thermal pyrolysis technique which was investigated in this study. Thermal pyrolysis technique is employed in a semi-batch type reactor to extract hydrocarbon fuels from the segregated waste plastics from the municipal waste. A maximum conversion rate of 99% is achieved at the operating temperature of 450 C and near atmospheric pressure. The properties of the liquid fuel extracted are close to commercial diesel. The combustion behaviour and emission characteristics of the extracted fuel blended with diesel percentage by volume 10% - 60% used in a compression ignition (CI) internal combustion (IC) engine are investigated. The brake specified fuel consumption (BSFC), break power (BP) and break thermal efficiency (BTE) of the engine were obtained for different fuel blends at various engine loads. The BSFC shows enhancement at all loads. Break power and break thermal efficiency were observed to be similar to that obtained with diesel. CO emission is higher than that of diesel and CO2, NO and NOx emissions were found to be similar to that of diesel. The net energy returned of the waste plastics to fuel conversion process was found to be 16,521 kJ/kg of the waste plastics and the developed reactor system is a sustainable approach for the waste plastic recycling.

Influence of Lead Contamination on Soil Index Properties: Implications for Geotechnical Engineering

2025-07-30T21:05:15+0530

The present study aimed to examine the impact of different concentrations of lead salts on a range of soil properties. This was achieved through a series of tests, wherein regression analysis was employed to establish quantitative relationships between the variables under investigation. The findings provided significant insights into the complex relationship between lead contamination and important soil variables. The regression equations exhibited evident and uniform patterns, thereby establishing predictive models for the variables of liquid limit, plastic limit, plasticity index, specific gravity, and moisture content. The models demonstrated a noteworthy level of explanatory capability, as evidenced by R-squared values that ranged from 0.6536 to an exceptional 0.9963. The regression analyses conducted in this study provide accurate and dependable predictive models for comprehending the complex relationships between lead salt concentrations and diverse soil properties. The potential applications of these models in environmental science, engineering, and soil management are underscored by their robustness, as evidenced by their high R-squared values. The results emphasise the necessity for ongoing investigation to enhance our comprehension of the intricate relationships between contaminants and soil, informing sustainable approaches for environmental well-being and remediation initiatives. study.

Smart Water Monitoring and Billing System Using IoT and Mobile Technology

2025-11-03T11:10:32+0530

This research aims to develop a smart water usage monitoring and billing system that leverages the Internet of Things (IoT) and mobile applications to replace conventional manual methods, which are often costly, time-consuming, and less reliable. The proposed system integrates a flow sensor with a Node MCU Wi-Fi module to collect real-time water consumption data and transmit it automatically to the ThingSpeak cloud server. The server computes the amount of water consumed and the corresponding billing amount at fixed intervals, initially set to every 10 minutes. However, this duration can be adjusted according to user requirements. MATLAB® is employed to process and analyse the transmitted data, ensuring accuracy in both consumption tracking and cost estimation. The processed outputs are then delivered directly to a mobile application, providing users with convenient, continuous access to their daily water usage and associated charges. Results from the prototype demonstrate that the system can reduce manual labour, minimize operational costs, and improve transparency by allowing users to monitor and manage their water consumption proactively. Overall, this study highlights the potential of IoT-enabled mobile solutions to modernize utility services and serve as a foundation for future smart water management systems.

Keywords: ThingSpeak cloud server, NodeMCU, Internet of Things

Preliminary Phytochemical Screening and In-Vitro Evaluation of the Anthelmintic and Antibacterial Activities of the Aqueous Extract of the Rachis (koor) of Azadirachta indica

2025-12-08T10:00:28+0530

Helminthiasis and bacterial infections remain major global health issues, highlighting the need towards safer and more effective anthelmintic and antimicrobial agents. In Siddha Medicine, the rachis (koor) of Azadirachta indica is traditionally used in decoctions, yet its aqueous extract remains scientifically unexplored in Sri Lanka. This study evaluates the dose-dependent anthelmintic activity, antibacterial effectiveness and preliminary phytochemical screening of the aqueous extract of Azadirachta indica rachis. Anthelmintic activity against Pheretima posthuma displayed clear dose-dependent activity, with the highest concentration (200 mg/mL) resulting the shortest mean paralysis (31.0 ± 1.0 minutes) and death times (56.0 ± 2.0 minutes), effective than to albendazole 10 mg/mL (36.7 ± 1.5 minutes paralysis; 61.0 ± 1.5 minutes death). Even the lowest concentration (50 mg/mL) resulted significant activity, indicating effectiveness across all doses. Antibacterial activity against Escherichia coli and Staphylococcus aureus, resulted in inhibition zones of 12 ± 0 mm and 11 ± 0 mm, respectively, indicating broad-spectrum efficacy to bacteria. Phytochemical screening detected tannins, glycosides, steroids, saponins, and flavonoids, which possibly act synergistically to mediate both effects. These findings suggest that the aqueous extract of Azadirachta indica rachis possesses excellent dual anthelmintic and antibacterial properties, supporting its traditional usage, and highlight its potential for development into natural, safe, and cost-effective plant-based therapeutic agents.

Development and Evaluation of Nutrient-Rich Functional Cookies Using Moringa Leaves and Palmyra-Based Ingredients

2026-01-12T11:54:10+0530

This study focused on the development and evaluation of nutrient-rich functional cookies using underutilized, cost-effective palmyra-based ingredients and moringa leaves. Moringa (Moringa oleifera) leaf powder and palmyra (Borassus flabellifer) based ingredients, specifically palmyra sprout flour and jaggery, were incorporated to formulate a healthier alternative to conventional cookies, which are typically high in refined sugar and low in essential nutrients. Cookies were prepared using different ingredient ratios, and the most acceptable formulation was selected through sensory evaluation. The cookies made from the best formulation were evaluated for proximate composition, mineral content, antioxidant activity, antimicrobial activity, and microbiological safety. The results demonstrated that the developed cookies possessed a significantly higher nutritional value compared to control samples (Control sample was made of all purpose flour and palm jaggery). The nutritional analysis revealed that the cookies were a rich source of protein (8.46 g/100 g), potassium (201.34 mg/100 g), and calcium (93.15 mg/100 g), a moderate source of iron (0.61 mg/100 g), and provided adequate energy (359.80 kcal/100 g). The antioxidant activity (IC₅₀ = 25.63 mg/mL) confirmed the presence of bioactive compounds contributed by moringa leaves and palmyra-based ingredients. Microbiological evaluation, including total plate count (1.2 x 10³ cfu/g) and yeast and mould count (< 1 x 10²cfu/g) , indicated that the product was safe for consumption and complied with Sri Lanka Standards (SLS 251:2010). Overall, the developed cookies can be considered a palatable, functional, and nutritionally fortified food product, offering a promising healthier snack alternative that may contribute to improved nutrition and help address malnutrition-related health concerns.

A Multifunctional Mobile Application for Enhancing Paddy Farming Efficiency

2025-11-13T12:11:42+0530

Paddy farming remains a cornerstone of Sri Lanka’s agricultural economy, yet productivity is often limited by inefficient resource use and dependence on traditional farming practices. This study presents a multifunctional mobile application designed to enhance paddy farming efficiency through intelligent monitoring, crop management, and decision support. The proposed system integrates modules for pest identification, irrigation scheduling, fertilizer recommendation, and market price forecasting. Using adaptive learning algorithms, the application analyses user behavior and environmental data to deliver personalized suggestions. Experimental evaluation demonstrates improvements in accuracy and timeliness of decision-making, leading to more sustainable and productive farming practices.

Technology-Integrated Teaching in Higher Education: An Empirical Study on AI-Supported Learning, Digital Tools, and LMS Innovations

2025-11-26T08:17:23+0530

Technology integration has become a cornerstone of innovation in higher education, driven by rapid advancements in artificial intelligence (AI), digital learning tools, and Learning Management Systems (LMS). This study examines how university students perceive and engage with technology-integrated teaching practices, especially AI-supported learning, digital tools, and LMS innovations. Using a quantitative survey-based methodology, data were collected from 320 undergraduate and postgraduate students at a Sri Lankan university offering blended and distance-learning programs. The study aimed to (a) measure students’ perceived usefulness of AI-supported learning tools, (b) assess their satisfaction with technology-integrated teaching, and (c) examine the relationship between AI usage, LMS engagement, and learning outcomes.

A validated 38-item questionnaire measured four constructs: AI-Supported Learning, Digital Tool Use, LMS Engagement, and Perceived Learning Outcomes. Results indicate that students strongly support the integration of AI tools—such as automated feedback systems, intelligent tutoring interfaces, and generative AI chatbots—into teaching practices. Reliability analyses showed strong internal consistency (Cronbach’s alpha = .87–.93). Correlation and regression analyses reveal that AI-Supported Learning significantly predicts Perceived Learning Outcomes (β = .41, p < .001), while LMS Engagement (β = .36, p < .001) and Digital Tool Use (β = .29, p < .01) also contribute positively.

The findings highlight the growing relevance of adaptive, AI-enhanced ecosystems in higher education. The study recommends professional development for academic staff, structured policies on AI integration, and continuous enhancement of LMS design to maximize student engagement, autonomy, and academic performance.