Journal of the Sri Lanka Association for the Advancement of Science

Analysis of Fat Content and Fatty Acid Profile of Selected Bakery Products Available in Jaffna District, Sri Lanka

2026-04-30T03:45:18+00:00

High consumption of trans fatty acids and saturated fatty acids are detrimental to human health. Bakery products are one of main sources of these two types of fatty acids in the diet of many people globally. The objective of this study was to determine the total fat content and fatty acid profile of selected bakery products available in Jaffna markets with main emphasize on saturated fatty acids and trans fatty acid contents. Samples such as bread (n=17), bun (n=17), cake (n=16), pastry (n=12), doughnut (n=4) and bakery fats (n=5) were analyzed. The highest fat content was observed in pastry samples (21.63%-39.83%) and doughnut samples (31.66%-37.17%), whereas lowest fat content was observed in bread samples (1.00%-3.43%). All bakery products consisted considerable amount of elaidic acid. Highest total saturated fatty acid content was detected in pastry (17.25 g/100 g), whereas lowest was observed in bread (1.36 g/100 g). Highest total trans fatty acid content was detected in pastry samples (2.47 g/100 g) followed by doughnuts (1.54 g/100 g), cakes (1.03 g/100 g), buns (0.28 g/100 g) and bread (0.08 g/100 g). Significant variations in the fatty acid composition were observed within and between types of products. Therefore, regulations should be imposed to reduce the saturated fatty acids and trans fatty acids content of bakery products in Sri Lanka.

Knowledge and awareness of medicinal values of selected traditional rice varieties among villagers in Wellawaya, Sri Lanka: A pilot study

2026-05-18T05:42:46+00:00

Traditional rice varieties in Sri Lanka possess significant cultural, nutritional, and medicinal value. However, modernization of agriculture and replacement with high-yielding varieties has contributed to declining cultivation and erosion of indigenous knowledge systems. This pilot study aimed to assess the knowledge and awareness of medicinal values of selected traditional rice varieties among villagers in Wellawaya, Sri Lanka. A community-based cross-sectional descriptive survey was conducted among 30 participants selected through systematic random sampling. Data were collected using a pre-tested structured questionnaire through face-to-face interviews. Descriptive statistics were used to summarize demographic characteristics and awareness levels, while chi-square tests were applied as exploratory analyses to examine associations between demographic variables and knowledge levels. Findings revealed moderate general awareness of traditional rice varieties, with higher recognition of Suwadel, Kalu Heenati, and Maa Wee. However, knowledge of specific medicinal properties was limited. Although older participants and those engaged in agriculture demonstrated relatively higher knowledge levels, no statistically significant associations were observed (p > 0.05), likely due to the limited sample size and reduced statistical power inherent in pilot studies. The study indicates a gradual erosion of community-level knowledge regarding medicinal applications of traditional rice. These findings provide preliminary evidence to inform larger-scale studies and support policy initiatives aimed at preserving indigenous knowledge and promoting traditional rice varieties for nutritional and health benefits in Sri Lanka.

Controlled Sulfur Incorporation in SILAR-Deposited CdS Quantum Dots for Suppression of Interfacial Recombination in TiO₂ Quantum Dot-Sensitized Solar Cells

2026-05-04T04:48:36+00:00

Quantum dot-sensitized solar cells (QDSSCs) are limited by severe interfacial recombination and inefficient electron transport at the TiO₂/CdS junction. In this work, the interfacial charge dynamics were controlled by regulating sulfur availability during successive ionic layer adsorption and reaction (SILAR) growth of CdS quantum dots on mesoporous TiO₂ photoanodes. Sulfur was introduced in controlled molar ratios relative to the Cd²⁺ precursor to modify defect density and band alignment.

An optimum sulfur level produced a marked improvement in photovoltaic performance, where power conversion efficiency increased from 0.262% (undoped CdS) to 0.519%, accompanied by higher photocurrent density and open-circuit voltage. Electrochemical impedance analysis showed a strong increase in recombination resistance and a prolonged electron lifetime (0.017 s → 0.159 s), while Mott–Schottky measurements revealed a positive flat-band shift (−0.747 V → −0.588 V vs Ag/AgCl), indicating improved interfacial energetics. The enhancement originates from sulfur-induced passivation of surface trap states in CdS, which suppresses back electron transfer to the electrolyte and facilitates forward electron transport through the TiO₂ network. Consequently, performance enhancement is dominated by interfacial recombination suppression.

These results demonstrate that tuning sulfur incorporation during CdS growth provides a simple and scalable strategy to engineer interfacial charge transport and improve the efficiency and stability of TiO₂/CdS QDSSCs.

SOLVING DETERMINISTIC MULTI-OBJECTIVE ASSIGNMENT PROBLEMS USING ANT COLONY OPTIMIZATION ALGORITHM

2026-04-30T06:32:46+00:00

This study is proposing a metaheuristic algorithm known as Ant Colony Optimization Algorithm (ACOA) to solve deterministic Multi-Objective Assignment Problems (MOAPs). While single-objective assignment problems have only one objective to optimize, MOAPs have several conflicting objectives to optimize simultaneously, such as minimizing production time and maximizing the productivity. ACOA is well-suited to solve this type of problems to a certain degree of accuracy because of the adaptive search and the collaborative learning. In this study, the ACOA is applied to seek a feasible near optimal solution to the deterministic assignment model, where in the implementation of the algorithm, the artificial ants construct assignments based on pheromone trails and heuristic desirability derived from the probabilistic estimates. The mechanism of pheromone evaporation and probabilistic path selection permit the algorithm to locate the near optimal solution while adhering to a set of constraints. The proposed algorithm is coded in Python programming language and the efficiency of the algorithm in solving MOAPs is compared with an existing prominent method known as Technique for an Order of Preference by Similarity to Ideal Solution (TOPSIS). The proposed Multi-Objective Ant Colony Optimization Algorithm (MOACOA) is proven to be capable of solving large scale MOAPs in less computational time compared to the TOPSIS method. The extension of this study can focus on solving stochastic MOAPs.

Characterization of Domestic Auto Diesel Adulteration with Kerosine up to 20%

2026-07-11T04:51:03+00:00

As the fuel prices escalates fuel adulteration incidences are reported in domestically and diesel adulteration is most prominently reported specially in private transportation sector. This research was carried out to characterize and estimate the diesel adulteration with kerosine at a maximum range up to 20%. Domestic Diesel and kerosine samples obtained from a fuel station. Parameters: distillation, flash point viscosity were analyzed using ASTM methods. Further more blended samples were analyzed using FTIR to find out their chemical structures. Samples were blended in volume-to-volume ratios. Control samples were taken as original diesel sample and original kerosine sample that taken from fuel station. Samples were prepared as 5K (5% Kerosine + 95% Diesel), 10K (10% Kerosine + 90% Diesel), 15K (15% Kerosine + 85% Diesel), 20K (20% Kerosine + 80% Diesel). According to results, increasing the concentration of kerosene in the blends decreases the kinematic viscosity and IBP in distillation and flash point values of the blended fuel compared with authentic diesel, but increases these values compared with authentic kerosene. Authentic diesel flashed at 86°C, while kerosene flashes at 47.5°C. just adulterating even 5% kerosene causes a colossal 10.5°C drop (down to 75.5°C). By the time adulteration reaches 20%, the flash point plummets to 68.5°C. A lower flash point increases the risk of premature ignition and adversely effects the engine performance. Impact of adulteration observed every 5% increment of kerosene methodically reduces the viscosity (from 3.794 → 3.522 → 3.346 → 3.093 → 3.000 cSt). Fuel pumps and injectors rely on the viscosity of diesel for lubrication. Thinner, low-viscosity fuel resulting from kerosene adulteration could result with increase in friction, fuel pump wear, and injector leakage could be possible. Distillation Profile (IBP and 50% Recovery) Initial Boiling Point (IBP): Authentic diesel boiled at 186.6°C, while kerosene at 161.2°C. When kerosene is added to diesel, the IBP experiences an immediate drop to 185.2°C at a 5% blend, and steadily declines to 175.0°C at a 20% blend. 50% Recovery Temperature (T₅₀): This parameter shows a highly predictable, linear decline. Pure diesel's mid-boiling point is 292.6°C. As kerosene is blended in at 5%, 10%, 15%, and 20%, the T₅₀temperature drops systematically to 289.0°C, 286.8°C, 281.9°C, and 277.7°C correspondingly. There is not very much significance difference between blended samples and control samples. Since the differences between pure diesel and pure kerosene are structural (chain lengths and branching) rather than functional (they contain the same elements), new peaks appearing or disappearing was not observed. Overall results shows that diesel adulteration adversely affects on engine performance.