RMUTSB ACADEMIC JOURNAL

Reliability target setting of power distribution systems using data envelopment analysis

2023-07-04T13:00:04+07:00

This paper presents a Data Envelopment Analysis (DEA) based method to evaluate the efficiency of power distribution systems in urban, industrial, and rural areas, with the aim of setting appropriate reliability targets by comparing the performance of individual distribution feeders (known as Decision Making Units or DMUs), the DEA analysis considered factors such as load density, insulated cable percentage, and protective device count as inputs, and the reliability indices System Average Interruption Frequency Index (SAIFI) and System Average Interruption Duration Index (SAIDI) as outputs. The DEAP 2.1 software was used for the DEA analysis, and the results were analyzed to establish the reliability targets for individual feeders, in order to improve the reliability of the power distribution systems.

Editorial statement

2023-12-08T09:32:42+07:00

วารสารวิชาการ มทร. สุวรรณภูมิ ปีที่ 11 ฉบับที่ 2 (กรกฎาคม - ธันวาคม 2566) ประกอบด้วย บทความวิจัย (research article) จำนวน 9 บทความ และบทความวิชาการ (academic article) จำนวน 1 บทความ รวมทั้งสิ้น 10 บทความ ทั้งหมดเป็นบทความด้านคณิตศาสตร์ สถิติ วิทยาศาสตร์ เทคโนโลยี
การเกษตร และวิศวกรรมศาสตร์ ซึ่งตรงกับเป้าหมายและขอบเขต (aim and scope) หลักของวารสาร อย่างไรก็ตาม สิ่งที่น่าสังเกตในวารสารฉบับนี้ คือ กระบวนการวิเคราะห์ทางคณิตศาสตร์ถูกนำมาใช้เป็นเครื่องมือในการวิเคราะห์ข้อมูล (data analysis) ในงานวิจัยสาขาต่าง ๆ มากขึ้น ไม่ว่าจเป็นงานวิจัย
ด้านเทคโนโลยีการเกษตรหรือวิศวกรรมศาสตร์ ซึ่งแสดงให้เห็นถึงความสำคัญและความสามารถในการนำมาประยุกต์ใช้งานของวิทยาการข้อมูล (data science) และการวิเคราะห์ข้อมูล รวมถึงแนวโน้มของการทำงานวิจัยในอนาคตที่จะต้องมีการบูรณาการกับองค์ความรู้อื่นมากขึ้น เพื่อขยายและยกระดับ
ขอบเขตคุณภาพของงานวิจัยขึ้นไป
ทุกบทความในวารสารฉบับนี้ได้รับการประเมินคุณภาพทางวิชาการจากผู้ทรงคุณวุฒิในสาขาวิชานั้น ๆ แต่ละบทความมีความใหม่ มีความน่าสนใจและมีองค์ความรู้และเทคโนโลยีที่ทันสมัย ซึ่งจะเป็นประโยชน์สำหรับนักวิจัยและผู้สนใจทั่วไป ที่จะนำองค์ความรู้ที่ได้ไปต่อยอดงานวิจัยในระดับที่สูงขึ้น ตลอดจน
นำเทคโนโลยีที่เหมาะสมไปประยุกต์ใช้ให้เกิดประโยชน์ในทางปฏิบัติ กองบรรณาธิการขอขอบคุณผู้ส่งบทความทุกท่านที่เลือกวารสารวิชาการ มทร. สุวรรณภูมิ เป็นที่เผยแพร่ผลงานวิจัย และหวังเป็นอย่างยิ่งว่าวารสารฉบับนี้จะเป็นประโยชน์ต่อนักวิชาการ นักวิจัย และผู้สนใจทั่วไป

Binary systems of full terms arising from some mappings

2023-08-17T10:19:17+07:00

Full terms with an invariant set are special types of terms defined by full transformations with an invariant set on a finite set and variables from an alphabet applied in the theory of solid varieties. The set of all full terms with an invariant set is closed under the superposition operation under which the superassociative law holds. This work introduced three different binary operations on the set of all full terms with an invariant set and proves associativity. Moreover, tree languages of full terms with an invariant set and their operations were considered. Finally, embedding theorems of semigroups of full terms with an invariant set into semigroups of tree languages of full terms with an invariant set were proposed.

Snowball sampling in the carbon footprint research of unregistered populations in the Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Suphanburi Campus

2023-05-31T14:05:35+07:00

This research studied the snowball sampling of the unregistered population of environmentalists in the faculty of science and technology from the unregistered population in the faculty. It was found that the snowball sampling was appropriate for a small sample size. The selection of a linear snowball sample was suitable for a maximum size of 20 samples, and the non-discriminatory exponential snowball sample was suitable for maximum size of 16 samples. Carbon footprint emission in the faculty of science and technology was divided into 3 scopes: scope 1, the direct carbon footprint emissions, i.e. traveling to the university (9,312.21 kg CO₂e/unit), scope 2, the indirect carbon footprint emissions, i.e. electricity and water consumptions in the faculty (47,768.28 and 176.26 kg CO₂e/unit, respectively), and scope 3, the other carbon footprint emissions, such as paper usage, plastic water bottles and paper usage in the faculty (1,132.98, 1,589.86 and 13,504.54 kg CO₂e/unit, respectively). In conclusion, the highest emissions of carbon footprint per year of the faculty was the electricity and water usage. Therefore, carbon footprint should be reduced by converting electricity to solar energy, the use of solar cell and incandescent lamps UV and emit less heat, to save electricity costs and to perform a save water campaign in the faculty. In addition, there should be a campaign for planting a tree in the faculty to absorb 9-15 kilograms of carbon dioxide on average. The goal will be set to reduce carbon footprint to zero or net zero by 2 people in the university reduce the temperature as 2-4 degrees Celsius and control the temperature not to rise, as well as expanding the conservative units.

Effect of Zr content on the structure and hardness of CrZrN thin films prepared by reactive DC magnetron co-sputtering method

2023-05-23T16:30:08+07:00

In this research work, a nanostructured chromium zirconium nitride (CrZrN) thin film was deposited on Si(100) by reactive DC magnetron co-sputtering method at room temperature. The effects of zirconium content on the structure and hardness of the as-deposited thin films by varying the sputtering currents applied to the Zr target (I_Zr) in the range of 300 mA to 900 mA, while the current of Cr target (I_Cr) was kept at 300 mA were investigated. The crystal structure, microstructure, morphology, thickness, and chemical composition were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy-Dispersive X-ray Spectroscopy (EDS) techniques, respectively. The results showed that increases in I_zr enhanced the deposition rate from 7.9 nm/min to 17.9 nm/min and increased the Zr content in the as-deposited films from 6.71 at% to 45.91 at%. The as-deposited films were formed as a (Cr, Zr) N solid solution, with fcc structure in (111), (200), and (220) planes. The lattice constant increased from 4.164 Å to 4.485 Å, whereas the average crystallite size decreased from 9.8 nm to 2.8 nm, showing that the as-deposited film has a nanocrystalline. The FE-SEM micro-images of all the CrZrN thin films showed compact columnar structure and dense morphology as a result of various Zr content in the films. Moreover, the thickness of the thin films was in the range of 475-1075 nm. The as-deposited film in this research work composed of chromium, zirconium, and nitrogen in different ratios, depending on I_zr. The hardness of films measured by the nano-indentation technique increased from 9.1 GPa to 18.6 GPa with respect to an increase in zirconium content and a decrease in average crystallite size.

Antioxidant activity, vitamin C and total phenolic contents in three types of lettuce grown in hydroponics and soil-based

2023-05-18T09:53:13+07:00

The objective of this study was to investigate antioxidant activity by DPPH assay, vitamin C and phenolic compounds content in three types of lettuce such as green cos, red cos and butterhead produced in hydroponic system and soil-based cultivation system from vegetable farmers near Ubon Ratchathani University. The results showed that antioxidant activity of green cos and butterhead had no significant difference between the cultivation systems while red cos had a significant higher value in soil-based systems. Comparison the antioxidant activity values between lettuce types at the same cultivation systems, green cos and red cos obtained similar value (67.45±6.71-89.83±4.30%) which was higher than that of butterhead (40.60±6.64-53.88±13.04%). For vitamin C and phenolic compound contents, the results revealed that there was no significant difference either hydroponic or soil-based system. However, there was significant difference between lettuce types at the same cultivation systems. For vitamin C contents, the results showed that green cos and red cos obtained similar values in the range of 195.20±10.75-213.22±18.59 mg/100 g of sample that was higher value than that of butterhead (79.36±0.51-95.33±9.89 mg/100 g of sample). For phenolic compounds content, the higher value was exhibited by green cos in the range of 15.80±0.85-18.98±0.76 mg GAE/100 g of sample while red cos and butterhead obtained similar value in the range of 10.95±0.47-12.90±0.27 mg GAE/100 g of sample.

Clustering of yardlong bean lines and cultivars grown under a drought condition

2023-05-03T13:13:12+07:00

The effect of drought stress significantly influences yield improvement and declining crop production. Therefore, this experiment aimed to the group and select 25 genotypes of yardlong bean lines and cultivars grown under drought-stress conditions. They were laid out in a randomized complete block design with 3 replications under the water-constrained condition in a rainproof greenhouse. Yield/plant and other 12 horticultural traits were recorded, and multivariate analyses were conducted to assess genetic divergence using Mahalanobis D² statistics, and the genotypes were grouped into clusters following Tocher’s method. The results showed that yardlong bean lines and cultivars grown under drought were classified into 7 clusters. Clusters I – VII contained 6, 10, 2, 2, 1, 3 and 1 genotype (genotypes), respectively. The inter-cluster distance (D²) was found to be the maximum between clusters V and VII (52.27), and the same was the minimum between clusters I and IV (11.21). Pod width contributed maximum to the total divergence followed by yield per plant and leaf greenness (SPAD) (22.00, 17.67 and 12.33 %, respectively). Therefore, the clustering of genetic divergence, in selecting lines from crossing between genotypes of clusters V and VII, can achieve high gains of selection and high-yielding lines for planting in drought conditions.

Quality evaluation of Kaew Kamin mango with specific gravity at commercial maturity stage

2023-06-29T10:01:38+07:00

Kaew Kamin mango is one of the economic important crops of Sa Kaeo province. Generally, Kaew Kamin mango is consumed in the unripe stage with crunchy texture, slightly sour and sweet taste. The best quality of mango depends on suitable harvesting stage (maturity), however most farmers classify the maturity stages by visual assessment which lack of accuracy. Therefore, this research aimed to study in relationship between specific gravity (SG) and physicochemical and physiology properties of the mango quality at commercial maturity stage. Unripe mangoes at commercial maturity stage were cleaned and divided into two groups: floating in water (T1) and sinking in water with floating in 2% sodium chloride (NaCl) solution (T2). The physical, chemical and physiological properties for each mango group were investigated. It was found that fresh weight, total soluble solids content (TSS), titratable acidity content (TA) and moisture content of mangoes varied significantly (p<0.05) with both floating and sinking in water. T2 group was showed the good properties for unripe mangoes, considering as mature. The peel was light green color with L^*, a^*, b^*, C^* and H^° values of 60.80, -10.06, 36.79, 40.63 and 105.57, respectively. The pulp of mango was orange-yellow color with L^*, a^*, b^*, C^* and H^° values of 75.30, 3.54, 42.48, 41.97 and 85.94, respectively. Its pulp had high starch concentration and TSS (9.24 °brix). TA and moisture content of T2 group were low values at 3.75% and 85.13%, respectively, which were significantly different compared to T1 group. In conclusion, SG method can be used to separate the Kaew Kamin mangoes quality at commercial maturity stage.

Application of factor rating for production layout selection to improve production: Case study rail joint production

2023-05-12T13:59:39+07:00

The objective of this research was to improve the rail joint production by developing the production layout and selecting the suitable production layout. The study was done by analyzing the value stream mapping current state together with flow diagram and outline process chart in order to study the problem condition and analyze the problem with why-why analysis technique. Four rail joint production layouts were designed on purpose to make a decision and also factors influencing on selection of those layouts were included. In this study, the determination of proper factors, concerned with Index of Item-Objective Congruence (IOC) with value above 0.5, was obtained from experts. Then, a method of pairwise comparison was employed to construct weight of those factors. Consistency ratio was also tested with satisfied score of 0.09, lower than 0.10. The primary outcomes showed that factors with their weights having an effect on layout selection were as follows: capability of management and production control, change of production volume, cost of improvement, period of improvement and distance with weights of 0.36, 0.34, 0.13 and 0.05, respectively. As a consequence, according to scores of four production layouts in relation to those five factors, the highest scores of 3.31 belonged to the third layout. This layout led to decrease 40 m of distance, 50,000 baht of improvement cost, and increase 6-10% of production volume with high management capability and production control compared to the original layout.

Mathematical modeling for stabilized plate controlling

2023-08-24T10:24:43+07:00

The stabilized plate is a device designed for various applications with high safety requiring, involving the movement of delicate and fragile items in hospital to keep patients position stable to prevent potential harm or danger. This research introduces the design of a stabilized plate control system using a Linear Quadratic Regulator (LQR) control scheme. The mathematical model was constructed using Lagrange^,s equation to aid in calculations. MATLAB/Simulink software was then used to create a motion model for the stabilized plate. Real-world experiments were conducted using an acceleration sensor to measure the tilt angle of the stabilized plate. MATLAB/Simulink was also employed to control the stabilized plate’s position. Simulation results showed that the system took approximately 1 second to reach the equilibrium position, which was the balance state of the system. In real-world experiments, it was observed that the designed control system can maintain the balance of plate within approximately 2 seconds when the plate became tilted.

Laboratory performance evaluation of a low-cost capacitive soil moisture sensor for fine- and medium-textured soils

2023-06-07T09:29:51+07:00

IoT soil moisture sensors, especially capacitive types, play a vital role in precision irrigation due to offering cost-effective and rapid soil moisture monitoring. However, low-cost capacitive sensors often require accurate calibration specific to agricultural soil textures. This study focuses on calibrating Soil Stick sensors, commercially available in Thailand, using fine and medium-textured soils from agricultural areas in Phetchaburi Province. The calibration process establishes an equation relating the sensor's output voltage, connected to the NodeMCU ESP32 microcontroller board, to volumetric water content. The calibration results revealed a third-degree polynomial equation with an RMSE value of 0.07 cm³.cm^-3. The performance evaluation was conducted using the calibrated Soil Stick sensor compared to the SM100 sensor, a factory-calibrated for various soil types. The Soil Stick sensor exhibited a lower RMSE value of 0.07 cm³.cm^-3, whereas the SM100 sensor had an RMSE value of 0.08 cm³ cm^-3. Furthermore, the confidence index of measurement (CI) demonstrated that the Soil Stick sensor achieved a value of 0.78, indicating a very good measurement performance, while the SM100 sensor yielded a CI of 0.66, denoting good measurement performance. The sensor's accuracy in soil moisture measurement was enhanced through calibration, enabling efficient control in irrigation applications.