ASEAN Journal of Scientific and Technological Reports

Comparative Evaluation of Ground Resistance Measurement Techniques and FEM-Based Modeling under Grounding Electrode Configurations

Amporn Boonram — 2026-07-26

Accurate estimation of ground resistance is essential for designing safe and reliable electrical grounding systems. This study investigates the performance of four representative electrode configurations—single rod, two parallel rods, three rods in a linear arrangement, and three rods in a delta arrangement—by combining experimental measurements with numerical modeling. The ground resistance values were measured using the 3-pole Fall-of-Potential (FOP) method and the 4-pole Wenner method and compared with results simulated via the Finite Element Method (FEM) implemented in the COMSOL Multiphysics Program. The analytical solutions were set under homogeneous soil conditions at the test site. The soil resistivity was first determined experimentally to establish the boundary conditions for the FEM model. The numerical model's accuracy was confirmed by simulation results that closely matched field measurements, with a relative error of less than 3%. Moreover, the results revealed that increasing the number of grounding rods effectively reduces total earth resistance. However, the reduction is nonlinear due to mutual coupling between the adjacent electrodes. The delta configuration provided the lowest resistance, followed by the three-rod linear arrangement. Overall, the study demonstrates that FEM analysis achieves high accuracy in predicting ground resistance under uniform soil conditions. The integration of numerical and experimental approaches supports the development of cost-effective and technically robust grounding designs for high-voltage and power distribution systems.

Quality, Nutritional, and Sensory Evaluation of Noodles Enriched with Oyster Mushroom (Pleurotus sajor-caju)

Nguyen Thi Ngoc Giang — 2026-07-23

Noodles are considered one of the staple foods, especially in Asian countries. Traditional noodles are typically made from wheat flour; however, their nutritional value is relatively low. Previous studies have also explored this topic with an emphasis on improving the nutritional quality of noodles, but the sensory quality was often poorly rated. Therefore, this study focuses on enhancing the nutritional and sensory qualities of noodles, thereby contributing to product diversification through the use of abundant local commodities in line with sustainable development goals. This investigation examined the optimal level of oyster mushroom flour incorporated into noodle formulations at 40, 50, 60, and 70 g, along with a control sample without mushroom flour. The formulation containing 60 g of oyster mushroom flour showed the most favorable nutritional, physical, and sensory characteristics. The selected sample received the highest scores for all sensory attributes. Noodles’ elasticity and cooking quality also performed well, with 59.28 g-force, high water absorption, and volume expansion (276.53% and 273.61%), and low cooking loss (2.90%). At the same time, this sample also contained higher levels of nutritional components and bioactive compounds, with 6.07 g protein, 1.94 g cellulose, 0.20 g β-glucan, 0.0051 g QE/100 g flavonoid, and 0.37 g TAE/100 g phenolic. These findings suggest that oyster mushroom flour can be used as a functional ingredient to improve the nutritional and sensory quality of noodles and may support the development of value-added mushroom-based food products.

The Optimization of Domestic Wastewater Dilution, Seed Volume, and Fertilizer Supplementation for Micractinium sp. Cultivation Using Response Surface Methodology

Muhamad Aiman Mohd Atarabusyi — 2026-07-23

Rapid urbanization has led to a growing domestic wastewater problem, posing environmental and public health risks. Conventional wastewater treatment remains inadequate, leading to issues such as eutrophication and secondary pollution. This study explores an alternative wastewater recycling method that utilizes domestic wastewater as a medium for cultivating Micractinium sp. and supplements it with a commercially available Nitrogen-Phosphorus-Potassium (NPK) fertilizer (13:13:21) as a novel nutrient source to enhance microalgae growth. The cultivation is carried out in an indoor system (25 ± 1 °C, 140 µmol m−2 s−1, 24:0 photoperiod, and continuous aeration) to determine the cultivation ratio (wastewater dilution: seed volume: nutrient concentration). Growth was monitored using optical and cell density parameters throughout the cultivation period (21 days) for each element of the ratio. After optimization using Response Surface Methodology (RSM) software, the ideal values of wastewater dilution, seed volume, and stimulant volume was 50%, 50 mL, and 110 mL, with the maximum growth (470nm), biomass (680nm), and cell density achieved were 6.57, 6.42, and 7.14 x 107 cells/mL, respectively. Therefore, the outcomes ratios per liter are 0.68 for diluted wastewater (domestic wastewater and filtered water), 0.10 for seed volume, and 0.22 for NPK concentration. These results highlight the potential of domestic wastewater as a medium for the growth of Micractinium sp., thereby supporting efforts to recycle wastewater to reduce environmental problems.

Antibacterial Activity of Fungal Endophytes Isolated from Kratom (Mitragyna speciosa) in Thailand

Nattawut Rungjindamai — 2026-07-23

Kratom (Mitragyna speciosa), which is an indigenous plant in Asia, has been used as traditional medicine for decades. This study focuses on fungal endophytes originally isolated from kratom and their antibacterial activity. Kratom plants were obtained from seven locations in Thailand. In each location, three plant parts, including leaves, stems, and roots, were collected. The plant materials were surface-sterilized and isolated for endophytic fungi on PDA amended with kanamycin. A total of 347 isolates of fungal endophytes were isolated, and 92 isolates were randomly selected for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. They were cultured in 50 ml of potato dextrose broth (PDB) at 25°C for 4 weeks, and the culture broth was tested against 4 bacteria using an agar well diffusion method. 11 isolates (12%) inhibited at least one bacterial species. Eight endophytes inhibited B. subtilis, while four, three, and one endophytes inhibited the other three bacteria, respectively. Six isolates of fungal endophytes were chosen for further screening. They were cultured in 2 L of PDB and incubated at 25°C for four weeks. After mycelium was separated, only culture broth was extracted three times with ethyl acetate using rotary evaporation, and the extracts were dissolved in DMSO before testing. Antibacterial activity was determined by disk diffusion, and inhibition zones were recorded. One crude extract (L1-01) partially inhibited E. coli (8.28 mm). In the three crude extract tests against S. aureus, L5-10 exhibited the highest activity (17.51 mm). Among four crude extracts inhibiting B. subtilis, R5-09 had the strongest activity (21.3 mm). These two fungal endophyte isolates (R5-09 and L5-10) were identified based on morphological and molecular characteristics and assigned to Aspergillus allahabadii and Aspergillus terreus, respectively. This finding emphasized that fungal endophytes from kratom have potential as a source of antibacterial substances and should be further studied for other bioactivities.

Prevalence and Factors Related to Stress and Depression Among Students at Nakhon Si Thammarat Rajabhat University

Hathairat Tunyarak — 2026-07-23

Depression and stress are prevalent mental health challenges among university students worldwide, particularly during the critical transition from adolescence to adulthood. This cross-sectional descriptive study aimed to examine stress levels, the prevalence of depression, associated factors, and predictors of depression among undergraduates at Nakhon Si Thammarat Rajabhat University (NSTRU). A proportional stratified random sample of 367 students in Years 1–4 (Semester 1, Academic Year 2024) was recruited. Data were collected using a 107-item, six-part questionnaire encompassing demographic characteristics, a multidimensional Stress Perception Scale, the SPS-T (20-item), the 2-Question Depression Screener (2Q), the 9-Question Depression Inventory (9Q), and the 8-Question Suicidality Assessment (8Q). Content validity (IOC > 0.5) and reliability (Cronbach’s α ≥ 0.78) were confirmed. Data were analyzed using descriptive statistics, Pearson’s correlation, and multiple regression. Most students reported low stress (55.59%) and screened negative for depression (71.37%); however, 28.63% were at risk of depression. Among the 105 screen-positive students subsequently assessed with the 9Q, 30.48% were classified as mild and 10.47% as moderate depression (equivalent to 8.7% and 3.0% of the full sample, respectively). Among students with mild-to-moderate depression (n = 43), 23.25% showed suicidal tendency. Religion was the only personal factor significantly related to stress. GPA, religion, and parental marital status were significantly associated with depression. All seven external factor domains (family, interpersonal relationships, academic, personality, health, financial, and environment) correlated significantly with both stress and depression. Multiple regression revealed that environmental, personality, family, GPA, and parental marital status collectively predicted 14.60% of depression variance (Adjusted R² = 0.117). Compared with middle-aged rural Thai populations in which occupational, health, and family stressors predominate, university students exhibited distinctly different stress source profiles, underscoring the need for age-group-specific mental health interventions. These findings highlight the importance of systematic, multi-component mental health programs within higher education institutions.

Comprehensive Assessment of Surface Water Quality in Ban Pru Toei Community Forest: Physical, Chemical, and Biological Parameters

Ameena Rakdee — 2026-07-23

This study conducted an integrated assessment of surface water quality in Ban Pru Toei Community Forest (42.56 ha), Bang Khan District, Nakhon Si Thammarat Province, Thailand. Water samples were collected in triplicate from five monitoring stations along a 3.05 km transect during the dry season of January–March 2023. Mean physical parameters across all stations were: temperature 26.13 ± 0.96°C (range: 25.00–28.00°C), total dissolved solids (TDS) 11.60 ± 0.13 mg/L (range: 7.56–18.40 mg/L), and pH 6.77 ± 0.13 (range: 6.15–7.05)—all compliant with Thailand's Pollution Control Department Class 1 standards. Mean dissolved oxygen (DO) was 4.36 ± 0.10 mg/L (range: 3.23–5.60 mg/L), with Station 2 (Waterfall) recording the highest DO (4.75 ± 0.07 mg/L) and Station 5 (Canal) the lowest (3.90 ± 0.10 mg/L). Mean water hardness was 14.65 ± 0.07 mg/L (range: 8.13–25.03 mg/L), well below the 300 mg/L Class 1 threshold. Biological assessment identified 22 families across 10 orders of aquatic macroinvertebrates; Odonata (5 families) was the most diverse order, followed by Ephemeroptera and Coleoptera (3 families each). Pollution-sensitive taxa (Perlidae, Heptageniidae, Ephemeridae) were present at Stations 2–5 but absent from Station 1, which was dominated by moderately clean water indicators (Filopaludina sumatrensis, 91.8% of individuals). This spatial distribution confirmed Class 1/2 ecological status at Stations 2 and 3, Class 2 at Stations 1 and 4, and Class 3 at Station 5. A modified Water Quality Index (WQI; formula: 0.3×Physical + 0.3×Chemical + 0.4×Biological) scored Stations 2 and 3 highest (86.7/100) and Station 5 lowest (68.3/100). These findings establish quantitative baseline data for the dry season, supporting adaptive management and community-based conservation strategies for this ecologically significant watershed. Year-round monitoring spanning the wet season is recommended to provide a complete annual baseline.

Development of Geopolymer Properties from Cement Industry Waste as Raw Material for Clay Pottery Products

Kantapon Setkit — 2026-07-26

This study demonstrates that cement industry waste (CCW) can be effectively utilized to produce high-performance clay–geopolymer hybrid ceramics with enhanced mechanical, physical, thermal, and durability properties. An optimum substitution of 20 wt% CCW achieved the highest compressive strength (42.5 MPa), compared with 31.4 MPa for the control, together with reduced porosity (22.1%) and water absorption (9.8%). These improvements are attributed to the combined effects of geopolymer reaction product development, improved particle packing, and microstructural densification, resulting in a dense and homogeneous matrix. Thermal and phase analyses suggest a progressive transition from geopolymer-dominated bonding to ceramic bonding during firing, with optimum densification at approximately 1050 °C, whereas firing at 1100 °C promoted over-fluxing and microstructural defects. The optimized composition also exhibited superior durability, retaining approximately 88% of its compressive strength after wet–dry cycling, and demonstrated good environmental compatibility, with heavy metal leaching below regulatory limits. In addition, CCW incorporation improved workability, reduced drying shrinkage from 6.5% to 4.0%, and enhanced surface quality while achieving comparable performance at lower firing temperatures than those typically required for conventional ceramics, suggesting the potential for reduced firing energy demand. Overall, the results demonstrate that CCW offers a promising and sustainable approach for producing durable, high-value ceramic materials while promoting waste valorization, resource efficiency, and circular economy practices.

Cost-Effective Artificial Media as Substrates for Mass Cultivation of Entomopathogenic Nematodes (EPNs)

James Pasaje — 2026-07-26

Entomopathogenic nematodes (EPNs) are eco-friendly alternatives to chemical pesticides in controlling agricultural insect pests, yet their mass cultivation remains constrained by high costs and ingredient availability. This study evaluated three cost-effective artificial semi-solid media for cultivating Heterorhabditis spp.: (A) egg yolk + mung bean, (B) egg yolk + fish meal, and (C) egg yolk + dog food. Each medium was inoculated with infective juveniles (IJs) and monitored weekly for 4 weeks, during which population density and physicochemical parameters (color, aroma, shape, and pH) were assessed. By week one, all media supported rapid multiplication, with no significant differences observed among treatments (A: 6,071.60 IJs/mL; B: 6,911.80 IJs/mL; and C: 7,546.20 IJs/mL, p = 0.279). From week two onward, significant differences emerged, with fish meal and dog food supporting higher population densities (9,221.60 9,221.60 ± 1,170.95 and 8,711.60 8,711.60 ± 1,303.25 IJs/mL, respectively) than mung bean (4,231.00 IJs/mL) (p < 0.001). Dog food medium sustained the highest populations through week three (4,682.20 IJs/mL) and retained the largest residual density by week four (287.00 ± 238.00 IJs/mL). Fish meal peaked highest (9,221.60 9,221.60 ± 1,170.95 IJs/mL) on the second week but declined thereafter. Mung bean, the sole plant-based medium, showed descriptive premature deterioration in shape by week two and significant aroma decline by week three, leading to population collapse by week four. These findings establish dog food-supplemented medium as the most cost-effective substrate for sustained EPN mass cultivation.

Architecture Design for Enhancing Direct Client-to-Microservice Communication in an E-Participation Platform for Local Administrative Organizations in Suratthani Province, Thailand

Kanjana Phuakkhong — 2026-07-26

Public participation is essential for governance in a democratic system. Local Administrative Organizations in Thailand typically provide websites and social media platforms such as Facebook Pages and the Line application for e-Participation. However, there is a lack of specific applications designed for e-Participation that ensure secure, efficient communication and support rapid information exchange. This research aimed to design and evaluate a direct client-to-microservice communication architecture for an e-Participation platform in Local Administrative Organizations in Surat Thani Province, Thailand. We adopted a microservice architecture based on Domain-Driven Design (DDD), along with an API-first design and a database-per-service pattern. A message broker was adopted for asynchronous inter-service communication. We implemented JSON Web Tokens (JWT) with AES-256 encryption for system security and used Apache JMeter for performance testing. The performance testing followed ISO/IEC 25010 standards under varying loads to assess throughput, response time, and resource utilization. The performance testing showed that the system throughput could handle 16.67 requests per second at 5,000 concurrent users, with zero error rate. The time behavior testing demonstrated that the system maintained an average response time of 41-46 milliseconds, well below 1,500 ms. The resource utilization test showed that the CPU peak value fell within the expected range, indicating that the system is highly stable, unaffected by CPU spikes, and efficient in memory use. Overall, the system successfully passed all performance criteria. This architecture enabled real-world usage of scalable, secure, and efficient e-Participation platforms for Local Administrative Organizations.

In Silico Mining of Potential Anti-cancer Liver X Receptor β Agonists

Juan Piolo Miguel Señires — 2026-07-26

Cancer continues to be a leading cause of mortality worldwide, with the most common treatments such as chemotherapy and radiotherapy producing severe off-target effects. This study aims to identify potential therapeutic compounds by screening the Natural Products Atlas (NPAtlas) for potential agonists of the Liver X Receptor Beta (LXR-β). LXR-β is a nuclear receptor involved in lipid metabolism and is known to induce apoptosis in cancer cells when acted upon by an agonist. Screening of 36,310 compounds from the NPAtlas database was performed using molecular docking, pharmacokinetic filtering, absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiling, and confirmatory molecular dynamics simulations. From the initial dataset, 9 candidates passed the docking and ADMET criteria, and molecular dynamics simulations successfully validated 7 of them. Among these, Cis-veramycin E (NPA033420) and Solanapyrone E (NPA010954) emerged as top candidates. Cis-veramycin E demonstrated a high docking score (–9.31 kcal/mol), low root mean square deviation (RMSD) of <1.0 nm, minimal root mean square fluctuation (RMSF) of <0.3 nm, and a favorable ADMET profile, including Ames safety, good absorption, and moderate clearance. Protein–ligand interaction profiling revealed a binding profile similar to known LXR-β agonists, including hydrogen bonding with Ser278, π–π stacking with Phe340, and hydrophobic contacts across core residues. Solanapyrone E exhibited comparable binding stability and engaged the critical His435–Trp457 electrostatic switch via a salt bridge, but was flagged as Ames toxic, indicating a need for structural optimization. The results support the recommendation to identify the compounds as lead candidates for LXR-β-targeted cancer therapy.

Statistical Downscaling for Climate Change Studies: Comparing TCPG-GLM and Gradient-Boosted TCPG Models for Local-Scale Rainfall in Purwakarta

Fatkhurokhman Fauzi — 2026-07-26

Accurate rainfall projections are vital for climate adaptation and water resource planning in tropical regions, where rainfall patterns are highly variable and zero-inflated. This study evaluates the performance of two statistical downscaling approaches based on the Tweedie Compound Poisson-Gamma (TCPG) distribution for monthly rainfall modeling in Purwakarta, Indonesia: the generalized linear model with Tweedie distribution (GLM-Tweedie) and the nonlinear Tweedie distribution boosting model (TDboost). Using observational rainfall data from five stations and predictor variables from three Earth System Models (BNU-ESM, MIROC-ESM, and MIROC-ESM-CHEM), model performance was assessed using root mean squared error of prediction (RMSEP) and Pearson correlation coefficient. The results show that TDboost generally outperformed GLM-Tweedie in terms of predictive accuracy and temporal consistency. At Cibukamanah station, TDboost achieved the lowest RMSEP under the MIROC-ESM-CHEM scenario (90.63 mm), while its highest correlation was obtained under the BNU-ESM scenario (r = 0.88). Similarly, at Cisomang station, TDboost under the MIROC-ESM-CHEM scenario achieved an RMSEP of 109.75 mm and a correlation of r = 0.78, indicating improved predictive performance compared with GLM-Tweedie. These findings suggest that distribution-aware boosting techniques can better capture the nonlinear and zero-inflated characteristics of tropical rainfall. The results also indicate that the best-performing ESM may depend on the evaluation metric used, with MIROC-ESM-CHEM providing lower prediction errors at some stations and BNU-ESM showing strong temporal correlation when combined with TDboost. Overall, this study highlights the importance of combining appropriate statistical downscaling models with suitable ESM predictors for improving local-scale rainfall prediction in complex tropical environments.

Enhancing Flowering and Nut Development of Tacunan Dwarf Coconut (Cocos nucifera L.) through Plant Growth Regulators

Bernie C. Bacalso — 2026-07-26

Coconut production in Central Visayas, Philippines, is increasingly constrained by climate variability, recurrent drought, and alkaline soils that disrupt the reproductive cycle and limit yield by reducing spathe emergence, flower development, flowering time, and nut retention. This study evaluated plant growth regulators (PGRs) for enhancing reproductive performance in the Tacunan dwarf coconut (Cocos nucifera L.). Using a randomized complete block design, four treatments were applied to 10-year-old palms: control, auxin (100 ppm), ethylene (100 ppm), and combined auxin–ethylene (50 ppm each). Treatments produced distinct responses. Auxin accelerated spathe emergence by 16 days and raised female flower production to 90.50 per palm by week 8, yielding earlier and more prolific flowering. Ethylene reduced flower number to 58.16, but shortened time to flowering to 88.75 days and improved nut retention to 70.50 nuts per month, versus 46.33 in the control. The combination treatment gave intermediate results, indicating responses constrained by dosage or hormonal antagonism. Button shedding and delayed flowering, typically induced by alkaline soil (pH 7.98) and drought, were partially mitigated by auxin and ethylene, leading to enhanced cell enlargement and regulation of pollination. Although the four-month duration was insufficient to assess effects on nut size and weight, the results provide novel empirical evidence that PGR interventions improve coconut reproductive performance and establish a baseline for long-term strategies to stabilize coconut yields under stress-prone conditions.

Energy Efficient Micropropagation of Dendrobium cruentum Rchb. f.: Chemical Sterilization, Net House Culture, Sucrose Optimization, and Acclimatization Substrate Selection

Sainiya Samala — 2026-07-26

Dendrobium cruentum Rchb. f., a threatened native orchid of southern Thailand, faces extinction from habitat loss and over-collection; however, conventional micropropagation protocols remain economically inaccessible for most conservation programs due to high energy costs. This study developed an energy-efficient micropropagation protocol by evaluating sterilization methods, culture environments, sucrose concentrations, and acclimatization substrates. Six sterilization treatments were assessed: conventional autoclaving (positive control), four concentrations of Haiter® bleach (NaOCl; 0.5, 1.0, 1.5, and 2.0 mL/L), and a non-sterilized negative control. Seedlings were cultured under controlled-room (25 ± 2°C, 16-h photoperiod) or net house (ambient temperature, natural light, 70% shade) conditions with sucrose at 0, 20, or 40 g/L on half-strength MS medium. Acclimatization performance was evaluated using sphagnum moss, chopped coconut husk, and charcoal substrates. Chemical sterilization with 2.0 mL/L Haiter® achieved an acceptably low contamination rate of 10.00% versus 6.67% for autoclaving, while eliminating autoclave capital (USD 2,000–10,000), maintenance (USD 200–500/year), and energy costs (2–3 kWh/cycle), reducing sterilization expenditure by 60–70%. Net house culture combined with 40 g/L sucrose produced superior plantlets with 2.63 shoots, 14.33 roots, 3.60 cm height, and 1.14 g fresh weight, representing numerically more shoots (21%, p > 0.05), significantly more roots (68%, p ≤ 0.01), greater height (41%), and higher fresh weight (75.4%) than controlled-room culture, while substantially reducing operational electricity costs associated with climate-controlled culture rooms. Charcoal substrate achieved the highest acclimatization survival rate (85%). This integrated, low-cost protocol offers a practical, cost-effective tool for conservation and commercial production of this threatened native orchid.

Efficient Removal of Organic Pollutants Using Magnetic Biochar Derived from Corn Husk

Chetnipit Kunawong — 2026-07-26

The development of cost-effective and sustainable adsorbents for dye-contaminated wastewater remains a critical environmental challenge. In this study, a magnetic biochar composite (M/BCH) was synthesized from corn husk biomass through FeCl₃ impregnation followed by pyrolysis at 600 °C for 4 h. The physicochemical characteristics of the pristine biochar (BCH) and the magnetic composite were systematically investigated using XRD, FTIR, SEM/EDS, and N₂ adsorption–desorption techniques. XRD and FTIR analyses confirmed the successful incorporation of Fe₂O₃ into the carbon matrix, while SEM/EDS mapping revealed uniform Fe distribution (~12 wt.%). Textural analysis showed that Fe₂O₃ deposition reduced the BET surface area and pore volume, indicating partial pore occupation. The adsorption performance of BCH and M/BCH for methylene blue (MB) and methyl red (MR) was evaluated over varying contact times, initial concentrations, adsorbent dosages, and shaking speeds. BCH exhibited relatively higher MB adsorption, attributed to its higher surface area and mesoporous structure, whereas M/BCH showed higher MR removal compared to BCH due to modified surface chemistry, improved electrostatic interactions, and additional mechanisms such as complexation and π–π interactions. The M/BCH composite reached adsorption equilibrium within 120 min and showed increasing dye uptake with higher adsorbent dosage and shaking speed. Importantly, its magnetic properties enabled rapid and efficient post-treatment separation. Overall, the findings demonstrate that corn husk-derived M/BCH was an effective, multifunctional, magnetically separable adsorbent with potential for wastewater treatment applications.

Application of a Heuristic-Based System for Sustainable Faculty Routing and Workload Balancing in Cooperative Education

Aritath Siraphatwongkorn — 2026-07-26

In cooperative education programs, faculty supervisors are required to visit multiple industry sites hosting students, with each site imposing a distinct workload characterized by the number of assigned students, travel distance, and on-site activities. This study formulates the supervisory routing task as a Set Partitioning Vehicle Routing Problem with Equitable Workload Constraints (SPVRP-EW) and introduces a three-phase heuristic approach. The first phase generates feasible one-day trips within a strict time window constraint. The second phase selects a minimum set of trips that covers all locations using a greedy set-cover strategy with an efficiency-based tie-breaking rule. The final phase assigns the selected trips to six faculty supervisors to minimize the maximum–minimum workload gap while ensuring that each supervisor is responsible for an equal number of main trips. Using a real dataset of 24 placement sites across four provinces in Thailand, the proposed method generated 12 trips totaling 2,399.5 km. The solution achieved a maximum–minimum workload gap of only 2 points and a workload variance of 0.58. Extended experiments further demonstrate that the method outperforms two simulated manual plans, as well as random-cover and random-assignment baselines, in terms of total distance, number of trips, and workload variance. The heuristic remains robust under ±5–10% distance noise, with the workload gap staying within 4 points. In addition, synthetic instances with 50 and 100 locations can be solved in under one second, confirming their practical scalability. Relaxing the equity threshold beyond 2 points does not yield further improvement, indicating that the heuristic is already optimal for the studied instance. Overall, the framework serves as a decision-support tool that enhances both logistical efficiency and social sustainability by improving workload fairness in cooperative education supervision.

Development of a Top-Lit Up Draft Biomass Stove with a Combustion Chamber Level Adjustment Mechanism

Somboon Prasongchan — 2026-07-26

This project aims to develop adjustable-depth TLUD (top-lit updraft) biomass stove combustion chamber technology to enhance stove performance during operation. Three conditions must be met for stove performance testing. The TLUD biomass stove was available in fixed depths of 7” (FS-7) and 11” (FS-11), as well as adjustable depths of 7 and 11” (AS-7/11) during operation. The evaluation of the biomass stove's performance used the water boiling test (WBT) methodology to assess thermal efficiency (η), burning rate (BR), power (P), and water boiling time (BT). The test results indicated that the FS-7 exhibited the maximum thermal efficiency (18.60 ± 0.14%), whereas the AS-7/11 showed the highest burning rate and power output (50.05 ± 1.07 g/min and 12.91 ± 0.27 kW, respectively). The AS-7/11 required the shortest duration to boil water (6.83 ± 0.69 min). The AS-7/11 was appropriate for applications necessitating high firepower and speed for thermally demanding tasks and was compatible with various containers.

Enhancing Weather Pattern Recognition through Multi-Stage Sensor Data Fusion and Smoothing Regression

Fuangfar Pensiri — 2026-07-26

It is often harder to make accurate predictions with large, various intelligent sensor systems because of data noise and the high cost of traditional modeling methods like Numerical Weather Prediction (NWP). This paper presents a comprehensive framework that integrates multi-stage sensor data fusion and preprocessing with machine-learning-based pattern recognition to produce highly precise, computationally efficient analog weather forecasts. Our method uses a strict three-stage pipeline to clean up and combine raw sensor inputs. It uses historical data from a distributed network of 79 NOAA weather stations. There are three phases: filling in missing values, addressing outliers, and smoothing moving averages. Subsequently, a decision tree model is used to identify similar weather patterns and predict critical weather variables. Our method is effective because it makes predictions that are much more likely to be accurate than incorrect. The Root Mean Squared Error (RMSE) declined by over 99%, from 0.1715 to an amazing 0.0011014. The results show that combining targeted sensor data preprocessing with complex pattern recognition is a suitable methodology for making smart weather forecasting systems work. Rather than serving as a replacement for physics-based NWP models, the proposed approach should be regarded as a lightweight complementary tool for localized, short-term analog weather pattern recognition.

Enhancing Biogas Yield Prediction Using Artificial Neural Networks: A Case Study with Agricultural Residues

Thikhamporn Khemwong — 2026-07-27

Accurate prediction of biogas yield is fundamentally important for the proper running of anaerobic digestion (AD) processes, and it involves complex interactions between process parameters and very nonlinear interactions. To address this problem, the present study systematically developed and evaluated different ANN models for predicting biogas yield from the anaerobic digestion of agricultural residues, including rice straw, cattle manure (CM), and palm oil residues. In all, 200 experimental observations were used to develop the models, with feed pH, temperature, volatile solids (%TS), C/N ratio, and HRT (days) as input variables and biogas yield as the output variable. Five ANN models with different network depths and training algorithms were developed and evaluated. The various performance criteria used for model validation were R² (coefficient of determination), RMSE (root mean squared error), and MAPE (mean absolute percentage error). The experimental results showed that deep ANN models outperformed shallow architectures in modeling the nonlinear trends of the AD phenomenon. Among the tested models, the multi-layered ANN-4 with the Levenberg-Marquardt algorithm achieved the highest predictive accuracy (R² = 0.962, RMSE = 0.018 m³/kg VS, MAPE = 3.1%). Regression analysis and 10-fold cross-validation verified the generalization ability of ANN-4. Sensitivity analysis showed that the C/N ratio, volatile solids (%TS) and HRT were the most significant parameters affecting biogas yield, consistent with established anaerobic digestion mechanisms. Overall, the findings indicate that deep ANN models can be effective tools for optimizing agricultural residue-based anaerobic digestion systems.

Drinking Water Treatment Plant’s Sludge as an Adsorbent for Removal of Heavy Metals: Effects of Contact Time, Adsorbent Dosage, and pH Level

Mardwita Mardwita — 2026-07-27

Heavy metals such as chromium, lead, copper, iron, manganese, and vanadium are several common heavy metals that can enter the environment through industrial activities, wastewater plants, and much more. A high concentration of these metals may cause severe health issues for living things. To address this issue, the present study reports the removal of chromium (Cr) and lead (Pb) metal ions from aqueous solution by activated sludge as an adsorbent. The effects of contact time (15-120 min), adsorbent dosage (40-160 g/L), and pH level (2-11) were studied in a batch experiment. The adsorbents were characterized using an X-ray fluorescence spectrometer (XRF), a Fourier Transform Infrared (FTIR) spectrometer, and a Scanning Electron Microscope (SEM). Adsorption results showed that the adsorption capacity of Cr(III) and Pb(II) ions increased with increasing contact time, adsorbent dosage, and pH. The variation in adsorbent dosage showed the highest adsorption capacities for Cr(III) and Pb(II) ions, 4.13 mg/g and 4.91 mg/g, respectively, at pH 5, an adsorbent dosage of 40 g/L, and a contact time of 60 min. These findings show that sludge from drinking water treatment plants can be effectively and sustainably used as an adsorbent to remove heavy metals. These findings also encourage the reuse of local waste materials and help in creating new environmental technologies.