RMUTSB ACADEMIC JOURNAL

Low-cost dimensional measurement using an Arduino embedded system with real-time logging via Microsoft Excel Data Streamer

Worapong Phongphattarawut — 2025-12-03

This research aimed to develop a low-cost and user-friendly dimensional measurement method using an Arduino-based embedded system integrated with Microsoft Excel Data Streamer for real-time data logging. The system was designed to address the limited accessibility to high-precision measuring instruments due to their high cost. The prototype consisted of an Arduino board, a rotary encoder, an LCD-I²C display, and a signal conditioning circuit, with data transmitted to Excel in real time. Calibration was conducted using a Dial Test Indicator, and measurements were performed on 30 sample workpieces, with results compared against a standard measuring instrument. Statistical analysis (t-test, p>0.05) indicated no significant difference between the embedded measurement system and the standard instrument, demonstrating that the developed system achieved satisfactory accuracy and reliability. The system effectively minimized manual recording errors, enhanced data accessibility for general users, and supported applications aligned with the principles of Industry 4.0.

Maturity index of an advanced selection of processing-type guava cultivar P3

Supakorn Omsintaveechok — 2025-12-10

The processed-guava industry offers a wide variety of products. The Department of Horticulture, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University has conducted a guava breeding program for processing types. P3 is an advanced selection that shows commercial potential. However, this advanced selection has not been studied for its maturity index under Horticultural field, Department of Horticulture, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Nakhon Pathom province. The experiment was arranged as a completely randomized design (CRD) with 10 replications. Guava fruits were harvested at three different stages: 110, 115 and 120days after full bloom (AFB). The results showed that guava harvested at 115 and 120 AFB reached full development, with average weights of 374.10 and 368.30g as well as average widths of 8.47 and 8.38cm, respectively. These data were higher than those of fruits harvested at 110days after flowering. Similarly, at 115 and 120 AFB exhibited increased peel color values (L^*, a^* and b^*) and redness (a^*) of the flesh increased with fruit age, whereas lightness (L^*) and firmness decreased. Regarding chemical composition, the ratio of total soluble solids (TSS) / titratable acidity (TA) [TSS/TA] and the vitamin C content increased with fruit age. However, guava at 120days after flowering began to abscise from the tree. In conclusion, the maturity index for P3 processing-guava was based on days after full bloom, skin and flesh color. P3 processing guava should be harvested at 115 AFB, when the skin turns yellowish green and the flesh is pinkish red, and the chemical composition is highest.

Effects of fungicides combined with antagonistic fungi and bacteria on the mycelial growth of Fusarium spp., the causal agents of dieback disease in durian

Juthathip Jitnum — 2025-12-29

Dieback disease of durians is caused by Fusarium spp., which causes tree decline, reduced yield, and death in several growing areas of Thailand. Disease control is primarily based on fungicides, which have been continuously used, leading to the development of resistance to these fungicides in the pathogens. The integration of microbial antagonists with fungicides may offer a promising approach to the management of resistant Fusarium isolates and improving disease control efficacy. This research aimed to determine the sensitivity of Fusarium spp. to some fungicides and to assess the antagonistic efficacy of Trichoderma asperellum KU1 and Bacillus amyloliquefaciens KPS46 against Fusarium spp. on culture media, both in the presence and absence of fungicides using the dual culture method. The results revealed that 2 Fusarium isolates exhibited moderate resistance (MR), and 5 isolates showed resistance (R) to chlorothalonil, with EC₅₀ values ranging from 45.42-50.95 and from 146.85 to 661.32ppm, respectively. Six isolates demonstrated moderate resistance (MR) to mancozeb (EC₅₀=12.12-212.85ppm), while 3 isolates exhibited moderate resistance (MR) to difenoconazole (EC₅₀=32.15-35.82ppm). In contrast, no resistance was observed among the isolates to prochloraz (EC₅₀ ranging from <0.1 to 6.68ppm). All 7 Fusarium isolates were subjected to control by antagonistic microorganisms. T. asperellum KU1 demonstrated higher suppression ranging from 51.85-86.11%, compared to B. amyloliquefaciens KPS46, which showed inhibition rates of 2.72-62.50%. However, in the presence of difenoconazole at a concentration of 0.1ppm, the antagonistic bacterium KPS46 exhibited a 1.40-fold increase in its inhibitory efficacy against the fungicide-resistant Fusarium isolate. Therefore, further studies on the combined use of difenoconazole and the antagonistic bacterium KPS46 should be conducted for greenhouse management of durian dieback disease.

Synthesis of Pt–Fe core–shell nanocatalysts supported on TiO2 via sequential dry impregnation and electroless deposition

Akkarat Wongkaew — 2026-01-16

This study investigates the preparation of bimetallic core–shell catalysts, in which Fe serves as the core and Pt forms the shell on a titanium dioxide (TiO₂) support. Fe was deposited onto TiO₂ via the dry impregnation method with a fixed loading of 1.50wt%. Pt was subsequently deposited onto the iron surface using electroless deposition (ED). In the ED process, chloroplatinic acid (H₂PtCl₆) was employed as the Pt precursor, dimethylaminobenzaldehyde (DMAB) was used as the reducing agent at a molar ratio of 1:20, and ethylenediamine was added as a stabilizer at a molar ratio of 1:4. The deposition was carried out at pH 11.0-11.5 and 50°C. The experiments were designed to achieve Pt coverages of 0.20, 0.40, 0.60, 0.80, 1.00, and 3.00monolayers. Results showed that both the concentration of the Pt precursor and the pH of the solution decreased rapidly within the first 10minutes and stabilized after 30minutes. The corresponding Pt loadings obtained were 0.36, 0.57, 0.75, 0.92, 1.40, and 3.50wt%, respectively. N₂ adsorption-desorption analysis indicated that Pt deposition did not significantly affect the specific surface area of the Fe/TiO₂ catalysts. X-ray diffraction (XRD) revealed the presence of the anatase phase of TiO₂, with Pt peaks detected, while Fe peaks were absent. To further confirm elemental distribution, TEM–EDS mapping was employed, verifying the presence of both Pt and Fe, and confirming the core–shell arrangement of Pt and Fe supported on TiO₂.

Development of bio-based cooking oil-absorbing paper from rice straw fiber, kaffir lime (Citrus hystrix DC) fiber, and cassava starch (Cultivar 81)

Pawinee Theamdee — 2026-02-12

This study focused on the development of oil-absorbing paper from bio-based materials using rice straw fiber (RF), kaffir lime fiber (KF), and cassava starch (Cultivar 81) as the main components. The effects of KF incorporation at different proportions (0, 10, 30 and 50% by weight of rice straw) were investigated to evaluate the chemical, physical, mechanical, antimicrobial, and biodegradability properties. All samples were analyzed using FTIR spectroscopy to examine their chemical structures. The results showed a noticeable decrease in signals corresponding to hemicellulose and lignin after alkaline treatment, while the cellulose structure remained evident. Based on the analysis of physical and mechanical properties and oil-absorbing performance, the sample containing 30% KF exhibited the most balanced and optimal performance. This sample showed enhanced oil absorption, high porosity, suitable thickness, and a fibrous structure that facilitated efficient oil uptake, making it particularly suitable for food applications. Furthermore, the inclusion of KF effectively inhibited the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with the inhibition zone diameter increasing proportionally with KF content. However, a higher KF content slightly reduced the biodegradation rate, likely due to its antimicrobial properties that suppressed microbial activity in the soil. Overall, incorporating KF into rice straw-based paper significantly improved its oil absorption capacity, mechanical and hydrophobic properties, and antimicrobial activity, without compromising biodegradability. These characteristics highlight its promise as an environmentally sustainable material for oil-absorbing and packaging applications.

Study of tea extraction conditions on antioxidant activity and total phenolic content for ready-to-drink mulberry leaf and fruit tea product development

Piyawan Phansi — 2026-03-13

The objective of this project is to develop mulberry (Morus alba L.) leaf and fruit teas, which cultivated in Lopburi Province, by optimizing the preparing conditions for ready-to-drink mulberry teas with health benefits. The study determined the effects of extraction time and temperature on the antioxidant activity, and total phenolic content of mulberry leaf tea, mulberry fruit tea, and a blended drink containing both mulberry leaf and fruit teas. The results indicated that the optimal conditions were 100±0.50°C for 3 minutes for mulberry leaf tea, and 100±0.50°C for 10 minutes for mulberry fruit tea. The antioxidant activity of mulberry leaf tea, which measured using the DPPH and ABTS methods, was 273.53±1.96AAE/g tea and 15.18±0.11TEAC/g tea, respectively, with a total phenolic content of 183.69±1.52GAE/g tea. The antioxidant activity of mulberry fruit tea (100±0.50°C, 10 minutes) was 256.71±1.25AAE/g tea and 11.57±0.34TEAC/g tea, with a total phenolic content of 98.18±2.86GAE/g tea. Therefore, these tea extraction conditions were used to prepare ready-to-drink mulberry leaf tea, mulberry fruit tea, and a blended mulberry leaf–fruit tea for natural and sweetened formulations with the addition of stevia extract. Color analysis of the ready-to-drink teas using a colorimeter revealed that each formulation exhibited different color values. In addition, the ready-to-drink tea products under refrigerated conditions at 4°C indicated a shelf-life of two weeks.

Effect of high-temperature curing duration on the compressive strength of concrete

Bundit Sumniangpho — 2026-04-02

Concrete is an important construction material in civil engineering due to its strength and durability. However, its mechanical properties may be altered when exposed to high temperatures, particularly those related to coarse aggregates. The use of limestone aggregate could result in a reduction in compressive strength and the formation of cracks, whereas basalt aggregate with its high density and superior heat resistance, has the potential to enhance concrete strength. This research investigated the effect of high-temperature curing duration on the compressive strength of concrete using basalt as coarse aggregate. Cube-shaped concrete specimens (15×15×15cm) were tested at ages of 1, 3, 7, 14, 28, and 56 days under curing at ambient temperature (25°C) and high-temperature curing at 100°C for 3 and 6 hours, with a controlled water-to-cement ratio of 0.45 and coarse aggregate sizes of 3/4, 1/2, and 3/8 inch. The results showed that basalt aggregate consistently provided higher compressive strength than limestone aggregate under all curing conditions, especially at ages of 7 and 28 days with the compressive strength increased 10-22%, which an increasing of 10-18% and 15-22%, respectively. This enhancement was attributed to accelerated cement hydration at elevated temperatures and the superior strength and thermal resistance of basalt aggregate. The findings indicated that basalt aggregate is suitable for the design of early-age high-strength concrete in high-temperature environments.

Effects of factors in flux-cored arc welding process on the structure and hardness of 900A grade railway track

Phongsak Runkratok — 2026-05-11

This study aimed to investigate the effects of repair welding process parameters on the structure and hardness of 900A grade railway track using the Flux-Cored Arc Welding (FCAW) process. Four types of filler wires with different carbon equivalent (CE) values 0.684, 2.233, 4.600 and 0.743% were used. Prior to welding, the rails were preheated at 150, 250, and 350°C, followed by welding with 1, 2 and 3 passes. Heat distribution was then examined using a thermal imaging camera, which revealed that heat propagated radially outward from the weld center. The structures of the repaired rail sections welded with all four filler wires consisted primarily of pearlite and ferrite. Preheating at 150 and 350°C resulted in insufficient fusion between the weld metal and the rail base metal, whereas preheating at 250°C produced better metallurgical bonding with no visible boundary separation. The hardness results indicated that lower preheat temperatures led to higher hardness values compared to higher preheat temperatures. Additionally, Regarding the effect of the number of weld layers, the hardness decreases with increasing layers, and the overall structure becomes coarser. Statistical analysis further indicated that the type of filler wire, number of weld passes, and preheat temperature had significant effects on both the structure and hardness of the welded rail steel.

Effects of fermented growing media mixed with durian leaves, chicken manure, and vermicompost on growth and yield of red oak lettuce

Napapan Nimpanich — 2026-05-11

This research aimed to study the potential of local agricultural wastes, namely coconut coir, chopped coconut husks, durian leaves, vermicompost, and chicken manure, to develop suitable planting media for the growth and yield of red oak lettuce. The experiment was conducted using a Completely Randomized Design (CRD) with 6 treatments and 5 replications. The control treatment (T1) consisted of a basal mixture of soil, coconut coir, and chopped coconut husks. The subsequent treatments were supplemented with durian leaves (T2), vermicompost (T3), chicken manure (T4), a combination of chicken manure and durian leaves (T5), and a combination of vermicompost and durian leaves (T6). All planting media were composted for 60 days prior to planting, and the data of plant growth were collected at 42 days after transplanting. The chemical property analysis after composting revealed that the media containing chicken manure exhibited significantly higher electrical conductivity and primary macronutrient contents compared to other treatments, influencing the growth of red oak lettuce under a chemical-free production system. Treatment 5 yielded the highest of plant height, number of leaves, stem diameter, leaf greenness, fresh weight, and dry weight, followed by Treatment 4, which showed no significant statistical difference. Conversely, the control treatment produced the lowest yield. In conclusion, planting media developed from agricultural wastes, particularly the combination of chicken manure and durian leaves, demonstrating at high potential as an efficient alternative. This approach can effectively reduce reliance on chemical fertilizers while promoting cost-effective and sustainable resource utilization.

Experimental investigation of electricity generation from motorcycle coolant waste heat using thermoelectric modules

Pachara Charoendee — 2026-06-10

This research investigated the performance of electricity generation system using a thermoelectric generator (TEG) that directly converted motorcycle engine coolant waste heat into electricity under varying operating conditions. The experimental setup utilized a Honda Rebel 300 motorcycle with 5 TEG modules, which was installed with a prototype system connecting to the engine's cooling circuit. Experiments were conducted both in laboratory tests using a dynamometer, and in real-world road tests at vehicle speeds of 40, 60, and 80km/h under loads of 200 and 300N. The results demonstrated the successful generation of electricity by the TEG modules, with a maximum power output of approximately 0.82W. The average system efficiency ranged from 0.526% to 0.672%, correlating with the temperature difference across the hot and cold sides of the TEG modules. This study highlights the potential for motorcycle coolant waste heat recovery and its subsequent utilization