Thai Science and Technology Journal

A Comparative Analysis of the Break-Even Point for Rooftop Solar Panel Installation: A Case Study of C-Dormitory, Chiangrai College

Tue, 30 Jun 2026 00:00:00 +0700

This study investigates the feasibility and economic viability of installing solar photovoltaic (PV) systems to enhance energy efficiency and sustainability. The analysis focuses on electricity generation potential and investment evaluation using a case study of the C-Dormitory at Chiang Rai College, which offers optimal rooftop conditions for solar exposure and efficient energy production. Building electricity consumption data were used to design a system capacity aligned with actual demand, followed by a financial assessment using key indicators: payback period (PB), net present value (NPV), and internal rate of return (IRR). The results show promising financial returns across three scenarios. Scenario 1 yields an IRR of 34% and an NPV of 2,003,600 THB; Scenario 2 yields an IRR of 35% and an NPV of 2,013,007 THB; and Scenario 3 yields an IRR of 35% and an NPV of 2,017,860 THB. All scenarios share a similar payback period of 2 years and 10 months. Cash flow and cumulative income analyses reveal that Scenario 2 offers the highest stability, while Scenario 3 provides slightly higher total returns. Although Scenario 1 has the lowest IRR, it still ensures rapid payback and consistent income. This comparison highlights the importance of both cash flow consistency and revenue potential in investment decision-making.

Factors Influencing the Acceptance of RDF Waste-to-Energy Plant in the Context of Community Waste Management

Nathanon Jamngern, Pornnapa Sutawong, Det Wattanachaiyingcharoen — Tue, 30 Jun 2026 00:00:00 +0700

Community solid waste management, together with the transition toward clean energy, has become a major challenge faced by many countries worldwide. Although refuse-derived fuel (RDF) technology is widely regarded as a practical approach to waste management under the circular economy concept, its implementation continues to encounter significant difficulties. One of the key challenges is public and community acceptance, which remains a common issue in many regions around the world. This study therefore aims to examine the factors influencing public attitudes and decision-making, shifting the perspective from viewing the issue as a localized conflict to a broader consideration of the relationship between technology and society.

The results indicate that trust in the institutions responsible for project management, along with access to clear and transparent information, has a greater influence on public acceptance than economic incentives. These findings suggest that local opposition to such projects is not driven solely by economic concerns, but is also closely linked to policy gaps and shortcomings in government communication. Consequently, this study not only provides recommendations for the case study area but also offers broader insights into conflict management and stakeholder collaboration among government agencies, the private sector, and local communities. These insights can support the implementation of clean energy projects and the achievement of the Sustainable Development Goals (SDGs), and may be applied to other contexts, particularly in developing countries

The solutions of the Diophantine equations 17^x-3^y=z^2 and 17^x-5^y=z^2

Tue, 30 Jun 2026 00:00:00 +0700

In this paper, we investigated the non-negative integer solutions to the Diophantine equations 17^x-3^y=z^2 and 17^x-5^y=z^2. The results showed that (x, y, z) = (0, 0, 0) and (x, y, z) = (1, 0, 4) are the only non-negative integer solutions for both equations.

Development of a Soil Database System for Organic Cassava Production to Support Intelligent Agriculture Systems by Using Big Data Management Technology

Jakkrich Laosai, Suthep Naramart — Tue, 30 Jun 2026 00:00:00 +0700

This research aims to develop a soil database system for organic cassava production by applying open agricultural innovation, precision farming, and smart farming technologies. The proposed system enables real-time monitoring and assessment of soil properties via the Internet of Things (IoT) to determine optimal crop requirements. Big Data Management Technology is employed to process and manage large-scale agricultural data, combined with data mining and cluster analysis techniques to synthesize and classify environmental information from sensing and control devices. The experimental results reveal that environmental factors, such as light spectrum, light intensity, temperature, and soil humidity, significantly influence optimal crop requirement parameters. The developed system effectively supports intelligent agriculture by enhancing production efficiency and enabling organic cassava farmers to achieve sustainable, data-driven cultivation practices.

Chemical Composition and Bioactivities of Low-Grade Betel (Piper betle L.) Leaf Extracts

Panatda Machaui, Kusumarn Noipha, Amonrat Thanonkaew, Vilailak Klompong — Tue, 30 Jun 2026 00:00:00 +0700

Betel leaf (Piper betle L.) is an important economic crop in Phatthalung Province, Thailand. After grading for export, more than one ton of low-grade betel leaves is discarded daily. This study aimed to extract bioactive compounds, analyze the chemical composition, and evaluate the biological activities of low-grade betel leaf extract. The extraction was carried out using 95% ethanol assisted by ultrasonication. The chemical composition of the extract was analyzed using gas chromatography–mass spectrometry (GC–MS). Antioxidant and antimicrobial activities were also determined. The chromatogram revealed ten major compounds, with phytol, neophytadiene, and tolycaine as the predominant components, while phenol, 2-methoxy-4-(1-propenyl)-, eugenol and ergost-5-en-3-ol were identified as minor constituents. The extract exhibited a total phenolic content of 559.66 mg GAE/g and a total flavonoid content of 48.36 mg QE/g. The result showed antioxidant activity against both DPPH (IC₅₀=35.53 µg/mL) and ABTS (IC₅₀=95.63 µg/mL), and also inhibited nitric oxide production (IC₅₀=1,075.75 µg/mL), indicating anti-inflammatory potential. The extract also exhibited antimicrobial activity, inhibiting and killing Staphylococcus aureus and Escherichia coli. Additionally, scanning electron microscopy confirmed cell wall and membrane disruption in bacterial cells. These findings suggest that low-grade betel leaf extract possesses antioxidant, antimicrobial, and anti-inflammatory activities, highlighting its potential as a valuable raw material for the future development of health and cosmeceutical products, and its ability to add value to waste generated from export grading.

Effect of Drought Stress on Growth, Yield, and Seed Quality in Chia (Salvia hispanica L.)

Tue, 30 Jun 2026 00:00:00 +0700

Chia (Salvia hispanica L.), a member of the Lamiaceae family, is native to Mexico and Guatemala. Chia seeds possess high nutritional value, containing antioxidants and high levels of omega-3 and omega-6 fatty acids. Consequently, they are widely utilized, particularly in the cosmetic industry and as a major alternative source of omega-3. This significant economic potential encourages farmers to cultivate chia as a source of income. However, successful chia production requires meticulous management of various production factors, with water management being paramount. Inadequate soil moisture can lead to a significant reduction in yield. Therefore, this study aimed to investigate the impact of soil moisture levels on chia growth and yield. The experiment was conducted using a randomized complete block design with three soil moisture levels: 100%,70%, and 40% of field capacity (FC). The results indicated that the 40% FC treatment resulted in significantly lower plant height and canopy size after 7 weeks of controlled soil moisture. Furthermore, the 70% FC treatment exhibited the highest leaf temperature, which corresponded to a decrease in chlorophyll fluorescence compared to the control. Growth analysis revealed that the net assimilation rate (NAR) during weeks 7 to 10 was highest under controlled soil moisture conditions; however, there was no significant effect on the relative growth rate (RGR) or yield. Regarding seed quality, parameters such as germination percentage and germination index showed no significant influence from soil moisture levels. These findings suggest that the 40% FC is sufficient for optimal chia growth and yield under the tested soil moisture conditions

Effect of Yoghurt and Glucose Syrup on Physical and Sensorial Properties of Low-Sugar Gummy Jelly

Patchaploy Kittiperakit, Sirinda Kusump — Tue, 30 Jun 2026 00:00:00 +0700

The objective of this research was to study the effect of yoghurt and glucose syrup on the physical and sensory properties of low-sugar gummy jelly. Two types of yoghurt were investigated: commercial yoghurt A and a mixture of commercial yoghurt A and commercial drinking yoghurt B (AB mix), in combination with three levels of glucose syrup. The results showed that the combined effect of the main factors significantly influenced the pH, cohesiveness, and color values (L*, a*, and b*) of the yoghurt gummy jelly (p<0.05). The use of the yoghurt AB mix in combination with increasing levels of glucose syrup resulted in decreases in pH, cohesiveness, and L* value (p<0.05), while the a* and b* values increased (p<0.05). When considering the individual effects of the main factors, the type of yoghurt affected hardness and gumminess, whereas the amount of glucose syrup affected hardness and springiness (p<0.05). The use of the yoghurt AB mix resulted in increases in both hardness and gumminess values (p<0.05). Increasing the concentration of glucose syrup led to increases in hardness and springiness (p<0.05). Sensory evaluation revealed that yoghurt gummy jelly prepared using the yoghurt AB mix and glucose syrup at 15% and 17.5% received the highest scores for flavor, taste, texture, and overall liking (p<0.05). This research is the first to report the use of at least 50% yogurt in the production of low-sugar gummy jelly.

Evaluation of Phytochemical Contents and Antioxidant Activities of Unripe and Ripe Coccinia grandis Fruits Extracts

Sayun Paewong, Savita Chewchinda — Tue, 30 Jun 2026 00:00:00 +0700

Coccinia grandis (L.) Voigt is a ubiquitous tropical fruit used as food and has attracted attention as a potential natural source of antioxidants. The effects of solvent type and extraction method on C. grandis fruit at different ripening stages were investigated in this study. Aqueous extracts were produced by decoction, while ethanolic extracts were prepared through maceration from both unripe and ripe fruits. Total phenolic content, total flavonoid content, and total β-carotene content were determined. Antioxidant activities were evaluated using DPPH radical scavenging, ABTS radical scavenging, and ferric reducing antioxidant power (FRAP) assays. The results showed that the total phenolics and flavonoids in unripe fruits were highest in the ethanolic extract, while the ethanolic extract of ripe fruits exhibited significantly higher β-carotene content (p < 0.05). Importantly, the ethanolic extract from unripe fruits demonstrated the strongest antioxidant activity, as indicated by the lowest half-maximal inhibitory concentration (IC₅₀) of the extract in the DPPH assay (180.90 ± 20.25 µg/mL), along with the highest ABTS and FRAP values (55.94 ± 2.04 mg TE/g extract, 105.34 ± 4.39 mmol FeSO₄/100 g extract) among all samples. In comparison, decoction extracts showed relatively poor antioxidant activities, possibly due to heat-induced degradation of phenolic and flavonoid compounds during extraction. These results highlight the potential of ethanolic extracts from unripe C. grandis fruits as functional food or dietary supplement materials.