SAU JOURNAL OF SCIENCE & TECHNOLOGY

Develop a chatbot system to support financial services Lopburi technical college

Siripilai Promphaet, Chutima Pisarn — Sat, 13 Dec 2025 00:00:00 +0700

This study aimed to develop a chatbot system to support financial services at Lopburi Technical College and to evaluate its effectiveness. The system was developed using a LINE Official Account integrated with Dialogflow to provide information on travel expenses for official duties, advances and reimbursements, as well as expenses related to training, events, and international conferences. The research involved 346 personnel, with data collected from a sample of 190 individuals over a period of four months. The findings revealed that the chatbot system achieved an accuracy rate of 96.04% in responding to inquiries and significantly reduced the time required to obtain information from staff. Users reported a high level of satisfaction, with an average satisfaction score of 4.93 (S.D. = 0.26). Additionally, the system demonstrated a fast response rate (average score of 4.84) and enabled continuous access to information without the need for direct staff interaction. User feedback further suggested expanding the chatbot’s functionality to support other services, such as academic registration and personnel management, and enhancing its natural language processing capabilities to handle more complex queries. These improvements would contribute to a more efficient and sustainable service system.

Theoretical Investigation of R600a Flow Characteristics in a Capillary Tube Used in Refrigeration Systems

Sat, 13 Dec 2025 00:00:00 +0700

This research presents a theoretical investigation of the flow characteristics of R600a refrigerant through a small-bore tube, commonly called to as a capillary tube.The developed mathematical model is based on the homogeneous flow, accounting for the phase change of R600a along the capillary tube. The refrigerant enters as a subcooled liquid, transitions to a saturated liquid, then to a saturated liquid–vapor mixture and finally accelerates to sonic velocity at the tube outlet. The model was validated by comparison with previous studies, showing excellent agreement. The results indicate that as the mass flow rate increases, the pressure of R600a drops sharply. In addition, increasing the capillary tube diameter or the degree of subcooling necessitates a higher flow rate to maintain a constant pressure drop. Conversely, a rougher inner tube surface requires a lower flow rate, with the effect being more pronounced in larger-diameter tubes.

Process Improvement for Underbody Anti-Corrosion Coating Spray: A Case Study at an Automotive Manufacturer

Sat, 13 Dec 2025 00:00:00 +0700

The researcher investigated the operation of the automotive underbody anti-corrosion coating production line and found that the current process exhibits issues of paint film sagging and overspray deposition on the vehicle body surface. These defects cause disruptions in subsequent production stages, leading to machine downtime. The objective of this research is to establish standardized work procedures in the production line, reduce operational problems, and minimize coating material costs. Data were collected from all stages of the coating spray process, after which the root causes of problems were analyzed using the Why-Why Analysis technique. The development of standardized work instructions, with the spray gun pressure set and controlled at 80 bar. Furthermore, the procurement plan for coating materials was revised to achieve greater efficiency. As a result, the underbody anti-rust coating process in automotive manufacturing became more effective.

The results of the improvement in preventing underbody anti-rust coating flow indicate that, prior to the modification, 10 vehicles encountered this issue in October 2023. After the implementation in December 2023, the number of affected vehicles was reduced to zero, representing a 100% improvement. The number of defects observed at the fender area decreased from 27 cases to 6 cases after improvement, corresponding to a reduction of 77.78%. For the hood area, the number of defects decreased from 15 cases to 0 cases, achieving a 100% reduction. Additionally, the spray gun pressure standard was controlled at 80 bar. Furthermore, the problem of excessive procurement of coating material was addressed. The purchase quantity was reduced from 188 kg to 153 kg after the improvement, corresponding to a reduction of 18.62%. The overall improvement outcomes reflect the effectiveness of the measures in both process quality enhancement and efficient utilization of resources.

Physical and Mechanical Properties of Cement Mortar mixed with Recycled Spent Coffee Grounds

Kultida Bunjongsiri, Anunya Pradidthaprecha — Sat, 13 Dec 2025 00:00:00 +0700

This study examined the mechanical and physical characteristics of mortar that contains coffee grounds at volume percentages of 0, 10, 20, 30, 40, 50, 70, 90, and 100% in place of sand. The mortar's water content, flow, and control flow rate were tested at 110 ± 5 percent. The mortar's compressive strength was tested at 7, 14, 21, and 28 days of curing age. The effects of mixing the coffee grounds mortar were seen using a 500x Optical microscope to acquire the results. According to the test results, the combination needed more water when coffee grounds were used in place of sand. The water consumption of the mortar increased by 4.43% and 44.83%, respectively, when coffee grounds were substituted for sand. According to the strength test results, the rate at which the compressive strength of each mixture developed rose by 5.72% when 30% coffee grounds were added, and it fell by 11.29% when 100% coffee grounds were added. Further improvement of the combination is necessary because the compressive strength tended to decline and there was little strength development. Depending on the amount of coffee grounds, the mortar’s unit weight tends to reduce by 6.51 to 30.52 percent as the coffee grounds content rises. The uniform distribution of coffee grounds throughout the mortar sample was demonstrated by the Optical microscope images.

A Study on the Participation of Building Occupants in Environmental Management in Bangkok

Bancha Srijansai, Chaisri Tarasawatpipat, Phonnipha Boriboonsuksri — Sat, 13 Dec 2025 00:00:00 +0700

This cross-sectional descriptive study aimed to investigate the level of participation and personal factors affecting the level of participation in environmental management of residents in a condominium building in Bangkok. A sample of 323 samples was collected from the sample. Data were analyzed by descriptive statistics and ANOVA. The results showed that the most prominent factors were (1) residents’ participation in environmental management, environmental sanitation system,and (2)residents’participation in environmental management, safety system, which were at the highest levels, i.e. = 4.40±0.640 and = 4.40±0.602, respectively. The results of ANOVA and t-test on personal factors revealed that gender, income, and length of stay did not significantly affect the level of participation in environmental management. Residents with different household status, age, and highest level of education had different levels of participation in environmental management at the 0.05 significance level. This research will be useful in determining appropriate environmental management policies for condominium management in Bangkok.

Study of the Use of Primavera P6 Computer Program for Planning and Cost Planning for Construction Project Management

Suwimol Jairtalawanich, Thamma Jairtalawanich, Singhawapee Rattanavijit — Sat, 13 Dec 2025 00:00:00 +0700

This research aims to study the use of Primavera P6 program in planning the duration and cost of construction projects by analyzing the quantity of work, materials, labor and machinery from BOQ (Bill of Quantities) for planning and comparing costs. including using project performance indicators such as BCWP, BCWS, ACWP, CPI, SPI, CV, SV to assess the value and efficiency of the project from project simulation in 4 phases, found that 1. The project progressed 25%, BCWS value = 20,341,803.04 baht, SV value = -20,038,557.54 baht, CV value = -109,491,703.68 baht 2. The project progressed 50%, BCWS value = 33,980,146 baht, SV value = 6,180,297.5 baht, CV value = -108,137,343.72 baht 3. The project progressed 75%, BCWS value = 94,905,240.52 baht, SV value = 11,986,476.95 baht, CV value = -90,474,325.45 baht 4. The project progressed. 100% BCWS = 109,794,949.18 THB SV = 0.00 THB CV = -83,198,409.53 THB The results of this study show that Primavera P6 can help to make the planning and monitoring of construction projects more efficient by estimating the actual cost compared to the planned cost to improve the project management for maximum benefit.

A Study on the Impact of 2k±1 Harmonic Components on the Lifetime of Oil-Immersed Transformers

Siriwich Tudsuan, Shanaphat Dechnaraphat — Sat, 13 Dec 2025 00:00:00 +0700

This paper investigates the impact of 2k±1 harmonic components on the lifetime reduction of oil-immersed power transformers, aiming to prevent insulation degradation caused by excessive hot-spot temperatures. In the first stage, the top-oil and winding hot-spot temperatures were experimentally measured. The obtained results showed good agreement with the proposed mathematical model. In the second stage, transformer load cycles under overloading conditions were simulated, with the fundamental current ranging from 110% to 150% of the rated current. Ambient temperature data from Kanchanaburi Province, recorded by Meteorological Department Station No. 450201, were employed in the simulation. The results indicate that at 150% overloading, both the top-oil and hot-spot temperatures exceeded the permissible limits, leading to a reduction in transformer lifetime to only 0.72 years. These findings highlight the significant influence of harmonic distortion on transformer thermal aging and provide useful insights for preventing insulation failure and improving long-term power system reliability and planning.

The Study of Various Aspects of User Perception on the Mobile Application of AIoT-Based Air Quality Monitoring and Prediction for PM2.5

Sat, 13 Dec 2025 00:00:00 +0700

This research investigates the key factors that affect user satisfaction with the “AIoT-based Air Quality Monitoring System for Real-time PM2.5 Prediction in Urban Environments” mobile application. Conducted in the Nong Khaem District of Bangkok, the study employs a quantitative research methodology with a sample of 411 respondents who have used the application. The main objective was to identify the factors that influence user satisfaction.

The study's conceptual framework categorizes 17 independent variables into four primary criteria: Core Functionality & Data Reliability, Information & Presentation Quality, Actionable Insights & User Impact, and User Experience & Social Impact.

Data analysis, which employed descriptive statistics and multiple regression, revealed that respondents generally reported high satisfaction with the system, with a mean satisfaction score of 4.34 (SD = 0.74). The multiple regression model demonstrated a strong fit (R-squared = 0.7909), indicating that the four groups of variables explain a significant portion of the variance in user satisfaction.

In conclusion, the research emphasizes the importance of a well-designed mobile application that not only provides accurate and reliable data but also effectively communicates information through clear visuals, offers actionable advice for personal protection, and ensures a positive overall user experience. The findings present valuable insights for developers and policymakers aiming to enhance the effectiveness and user adoption of environmental monitoring technologies in urban areas.

Effects of Metastable flow on Flow Characteristics of R600a in Capillary Tubes Used in Refrigeration Systems

Pramote Laipradit, Worachest Pirompugd — Sat, 13 Dec 2025 00:00:00 +0700

This research presents a mathematical model for predicting the properties of R600a refrigerant flowing through a capillary tube, incorporating the effects of metastable flow. Metastable flow occurs because the refrigerant R600a will not change from liquid to vapor even when the pressure is lower than its vapor pressure. The location where the refrigerant R600a changes from liquid to vapor is shifted further away from its original location, resulting in a higher flow rate for the R600a refrigerant. The results of the developed mathematical model were compared with those from literature. The comparison reveals that the values are similar and trend in the same direction, ensuring a certain degree of accuracy. This study also presents the effect of metastable flow on the mass flow rate under various operating conditions. It was found that accounting for the metastable flow effect can increase the mass flow rate by up to 13.08%. Two selection charts are also presented to indicate the operating conditions and capillary tube sizes for R600a.