Rattanakosin Journal of Science and Technology

Development of Kaffir Lime (Citrus hystrix DC.) Jam Product Using Stevia Extract as A Sugar Substitute for Khon Hua Jai In-si Baan Nam Sub Phatthana Community Enterprise, Phatthana Nikhom District, Lopburi Province

Gannigar Onsamlee — 2026-04-30

This research aimed to: 1) develop a formula and production process for kaffir lime jam using stevia extract as a sugar substitute, 2) select suitable packaging and develop product labeling for the kaffir lime jam, and 3) assess consumer satisfaction with the developed product. The sample group for formula and production process development consisted of 50 general consumers selected purposively. Key informants for packaging selection and label development included 10 of leader and group members, and 50 general consumers. For the consumer satisfaction survey, the sample group consisted 10 of leader and group members, and 400 general consumers, selected through random sampling. The research tools included instruments for chemical and physical quality analysis, a Sensory Questionnaire for formula and production process development, focus group discussion questions for packaging selection and label development, and a consumer satisfaction questionnaire for the developed product. Data were analyzed using mean, standard deviation, and statistical analysis of variance (ANOVA). The results revealed that the kaffir lime jam product, using 40 percentage of stevia extract as a sugar substitute, had the best quality and was not significantly different from the control formula. The most suitable packaging was a 4-ounce glass jar with a net weight of 100 grams. The product label was designed to include essential information, while being visually appealing and suitable for the product. Consumer satisfaction surveys on product quality, packaging, labeling, pricing, and overall image showed the highest level of satisfaction across all attributes.

Analysis of Electrical Load Anomalies in Educational Buildings Using Isolation Forest and PCA for Dimensionality Reduction

Santi Karisan — 2026-04-30

This study utilizes Principal Component Analysis (PCA) and Isolation Forest to analyze energy data from the Industrial Technician School Building at the College of Industrial Technology and Management, Rajamangala University of Technology Srivijaya (Phase A, Phase B, Phase C). The analysis begins with data standardization and PCA to reduce the dimensionality of the data to two components, which helps in better understanding the structure and variance of the data. The results show that Principal Component 1 (PC1) and Principal Component 2 (PC2) explain a significant portion of the data variance, with PC1 being the most influential component in explaining the power data. Furthermore, Isolation Forest is used to detect outliers by calculating the Anomaly Score. The distribution of anomaly scores reveals periods in the energy data that may indicate abnormalities in the electrical system. This outlier detection helps in identifying potential issues in the system more quickly. The study demonstrates that Isolation Forest can effectively detect outliers, making it an important tool for identifying anomalies and reducing the risk of system failures. The combination of PCA and Isolation Forest enhances the ability to analyze and manage energy in the electrical system, enabling the detection and resolution of issues during specific time periods efficiently. This is crucial for maintaining and improving the stability of the electrical system.

Mechanical Properties of Sound-Absorbing Walls from High-Density Polyethylene Plastic Waste

Keattisak Kongkeaw — 2026-04-30

This research aimed to: 1) test the mechanical properties of mortar mixed with high-density polyethylene (HDPE) plastic waste; 2) test the mechanical properties of concrete blocks mixed with high-density polyethylene plastic waste, and 3) test the sound absorption of the wall mixed with high-density polyethylene plastic waste. Method of conducting an experimental study by using plastic waste remaining from the production process, namely high-density polyethylene plastic (HDPE), mixed to replace 10% of sand. The mechanical properties of mortar and concrete blocks were examined, and the sound absorption of walls was also evaluated, considering the possibility of their practical use in construction work. The findings revealed that: 1) Mortar mixed with 10% HDPE plastic waste had the highest compressive strength and tensile strength properties, which are 251.45 and 42.27 kg/cm², respectively, but lower than the standard mortar, with values of 334.28 and 48.10 kg/cm², respectively. 2) The mechanical properties of concrete blocks that were mixed with 10% HDPE plastic waste resulted in a compressive strength of 53.03 kg/cm², which is lower than the compressive strength of standard concrete blocks at 54.93 kg/cm². The mechanical properties of concrete blocks mixed with 10% HDPE plastic waste resulted in a compressive strength of 53.03 kg/cm² lower than that of standard concrete blocks at 54.93 kg/cm². 3) The wall mixed with 10% HDPE plastic waste absorbs sound at 500 Hz, reduced to 1.19 dBA, compared with the standard concrete block wall. The frequency at 1,000 Hz could absorb 7.69 dB, which was less noisy than a standard concrete block wall. In addition, the frequency at 1,500 Hz could absorb 17.03 dB, which is less noise than a standard concrete block wall. It is an added value for construction material products made from environmentally friendly plastic waste.

Economic Evaluation of Energy Management in the Palm Oil Industry through the Installation of Inverter High Efficiency Motors with SCADA Systems

Kanitpong Chitsopon — 2026-04-30

This study aims to evaluate the economic viability of energy conservation in the palm oil industry through the integration of variable frequency drives (VFDs) for speed regulation and operational control of high efficiency motors, complemented by a supervisory control and data acquisition (SCADA) system. The analysis focuses on energy consumption patterns within the palm oil processing sector and assesses the impact of implementing energy-saving measures involving VFD installation on high efficiency motors integrated with a SCADA platform. The results indicate a reduction in the energy consumption index by 7–37%, leading to a substantial decrease in electricity expenditure ranging from 14,071,705.03 to 20,772,516.94 THB per year. The investment demonstrates a remarkably short payback period of 0.13 years, or approximately 1.5 months, with an internal rate of return (IRR) of 7.90%, which is considered economically attractive. The project also yields a high net present value (NPV) of 5,063,828.69 THB, further reinforcing its financial soundness, enabling high efficiency motors to operate in alignment with real-time load demands and the VFDs enhance overall system efficiency. Simultaneously, the SCADA system ensures optimized performance monitoring, control, and data analysis, thereby supporting long-term value creation. These findings confirm the project's strong potential for investment based on energy economics, characterized by significant energy savings, rapid cost recovery, and favorable financial returns. The insights derived from this study can serve as a reference model for decision-making in similar energy optimization projects across industrial settings.

Degradation and Diffusion of Fenobucarb and Triazophos in Water in Furrows of a Fruit Farm to Namdang Canal, Bangbon District, Bangkok

Utumporn Sompong — 2026-04-30

Nowadays, there are pesticides that were focused because of concern of their residues in environments. Moreover, we found residue of some pesticides from carbamate and organophosphate groups in surface waters near agricultural area in Thonburi, Bangkok. Therefore, this research aims to study degradation of carbamate and organophosphate pesticide in water in furrows of a fruit farm continuously in a village of Wararom Petchakasem 81, Bangbon district and to study diffusion of the pesticides from the furrows to a nearest surface water, Klong Namdang. We sprayed fenobucarb and triazophos then randomized water samples were collected from 6 points distributed in the farm then put into a sample at 0, 3, 5, and 7 days after spraying. The canal water sample was collected as
the previous method for 0 days after spraying only. The water samples were assessed the contents of the pesticides by Liquid chromatography - mass spectrophotometer (LC-MS) and Gas chromatography - flame photometric detector (GC-FPD), respectively. The research was done during October, 2024 – June, 2025. Statistic F was used for analyzing variation and linear regression and statistic t was used for mean comparison, respectively. We found that means of content of the pesticide residues, in water in the farm collecting from different days after spraying the pesticides were not significantly different (p=0.7731). Moreover, the pesticides were degraded within 4.89 and 6.83 days after spraying with the degradation rate of 0.4110 and 0.2927 µg/l/day, respectively. It meant that the pesticides degraded in a closed rate. However, means of the residue contents in water in furrows of the farm and the canal were significantly different (p=0.0004). It meant that the pesticides may distributed from the farm to the canal. The results showed the risk of the pesticides to environment and health of the community because the residues were not in the standard of water quality of surface water identifying by Pollution Control Department and World Health Organization.

Nonlinear Static Analysis of Spherical Shells with Variable Thickness under Hydrostatic Pressure

Komkorn Chaidachatorn — 2026-04-30

This paper presents a nonlinear static analysis of spherical shells with variable thickness under hydrostatic pressure. The shell geometry with variable thickness along the meridian coordinate can be defined using differential geometry. The energy functional is formulated in terms of shell displacements based on the principle of virtual work. Nonlinear numerical results can be obtained by finite element method and direct iterative procedure. The results indicate that the spherical shells with variable thickness exhibit reduced tangential and normal displacements near the support condition when compared to those with constant thickness. However, the membrane forces and bending moments along the meridian and circumferential coordinates show only minor differences. Consequently, the present results are applicable to the design of spherical shells with variable thickness. Moreover, the maximum circumferential membrane force is occurred in the range of 070^o, and then decreases rapidly. The maximum meridian and circumferential bending moments are occurred in the range of 60^o90^o, and the maximum bending moments is occurred at the support.

An Energy and Exergy Efficiency Enhancement of Ice-on-coil storage Using Waste Heat

Taveewat Prommas — 2026-04-30

This research of energy efficiency and exergy efficiency of ice on coil storage system with waste heat recovery. The system consisted of 2 TR air conditioner with an ice storage volume 250 L that is well insulated. Inside the ice storage tank was installed with copper coil 15turns with inside diameter
9.5 mm. The system used R410A for heat exchange with the 210 L of water, initial temperature is 30˚C. The refrigerant from compressor flow through heat exchanger installed inside a waste heat tank 80 L and flow to the condenser. The experiment varied the electrical frequencies of the compressor to be 40, 45 and 50 Hz to relate with the waste heat at 70, 80 and 90˚C respectively. From a study of energy performance of system using ice storage at frequencies of 40, 45 and 50 Hz with waste heat recovery at 70, 80 and 90˚C, it found that at frequencies 40 Hz combined with the waste heat at 90˚C, the system had the highest coefficient and less electrical power when compare with the normal system is about 10.15%.Moreover the system varied the electrical frequency with the waste heat recovery is a nearly
the COP compare with the normal system without the waste heat is decrease when the time increase,
the exergy efficiency increase average about 8.0-18.0%, the energy efficiency of system average 89.0- 91.0%, the total electric energy saving 19.1%, and the best payback period is 2.11 years. It can therefore be applied to refrigeration and air conditioning systems in both industrial and residential sectors.

Vertical Planting and Energy Measurement are Designed and Developed using the ESP8266 and the Blynk IoT platform

Chaovarit Janpirom — 2026-04-30

The concept of urban farming and vertical farming is one of the concepts [1] that has arisen, which has received a lot of attention and has begun research and experimentation in many countries to solve the problems mentioned above. Vertical farming can be carried out all year round, uses limited space, can prevent diseases and pests, saves energy, but produces 5-10 times higher yields than conventional farming when compared to farming in the Samearea Saowani [6] The research on the design and development of materials for cone growing under automatic control was initiated from this cause, with the following goals: 1. Develop and apply materials for vertical cone growing controlled by Internet of Things technology. 2. Test the performance of the vertical cone growing system controlled by Internet of Things. 3. Study the energy utilization controlled by Internet of Things. The methodology Create planting materials in the shape of a vertical cone and include Internet of Things technology using the Node MCU ESP8266, which uses a relay and DHT11 to switch the system on and off. Additionally, it may be controlled with a mobile device via the Blynk application. The plants cultivated in cones in the testing room grew well, and it was discovered that the cone-shaped planting materials and the watering and liquid fertilizer system could operate in accordance with the instruction to switch on and off according to the stipulated length of time, which is 100%.

A Multi-Methodological Approach to Evaluating the Biological Activity of Erythropoietin Marketed in Thailand

Boontarika Boonyapiwat — 2026-04-30

This study evaluated and validated two analytical methods, an enzyme-linked immunosorbent assay (ELISA) and a cell-based bioassay, for the determination of erythropoietin in pharmaceutical formulations marketed in Thailand. Method validation was carried out following ICH guidelines. The ELISA method demonstrated high specificity, as the erythropoietin standard and formulated samples produced clear absorbance signals that were clearly different from those of the excipient matrix. The excipients alone showed minimal response, confirming that formulation components did not interfere with the assay. A strong relationship between absorbance and erythropoietin concentration was observed, and the method showed excellent linearity over the tested range, with coefficients of determination greater than 0.99 across three consecutive days. Accuracy results were acceptable for a biological assay, with recovery values within the expected range. Although some variability was observed in repeatability testing, this was consistent with the nature of immunoassays. Intermediate precision results were consistent across different days and analysts, indicating that the ELISA method is reliable for routine analysis. The cell-based bioassay also showed good specificity. Parallel dilution curves of the erythropoietin standard and sample demonstrated consistent relationships between response and concentration, while formulation excipients produced only weak signals. The assay was linear over a concentration range of 0.0625 to 1 IU/mL, with strong correlations observed over three days. Accuracy testing showed recovery values within acceptable limits, and precision results were within the expected range for cell-based assays, where higher variability is commonly observed. The precision of the assay across different days and analysts confirmed its robustness. In conclusion, both the ELISA and cell-based bioassay methods were successfully validated and shown to be suitable for erythropoietin determination. The ELISA method provides reliable quantitative measurement, while the cell-based assay effectively assesses biological activity and potency. Together, these complementary methods offer a practical and reliable approach for routine quality control of erythropoietin products.