Journal of Advanced Development in Engineering and Science

Factors Influencing the Growth Rate for Cultivation of Chlorella sp.: A Case Study of Nakhon Si Thammarat College of Agriculture and Technology

Ketmanee Sriin — 2026-01-20

The objective of this research was to compare the growth rate differences between Chlorella sp. cultured using the traditional method and pure Chlorella sp. cultivation and study the relationship between the number of Chlorella sp. cells and environmental factors. The traditional cultivation method uses inoculum from the Chlorella sp. production pond at Nakhon Si Thammarat College of Agriculture and Technology. The pure Chlorella sp. cultivation uses inoculum from the Songkhla Inland Fisheries Research and Development Center. The Chlorella sp. cultivation experiment was conducted in 1.5-liter plastic bottles under a light intensity of 2,000±500 lux, with a 24 hour light exposure period. A plant nutrient solution was provided with an initial electrical conductivity (EC) of 0.7 mS/cm and a pH of 6. The initial Chlorella sp. cell count was 3×10³ cells per milliliter (cell/ml). Chlorella sp. cell counts were recorded using haemacytometer. Data on air temperature, water temperature, relative humidity, pH, and EC were collected once daily for 20 days. The study found that Chlorella sp. from the pure inoculum average cell count was 1.716×10⁷ cells/ml, significantly higher than the traditional cultivation method (p<0.05). The average pH was 7.40±0.97, the average EC was 0.63±0.05 mS/cm, and the average water temperature was 30.69±0.80 °C. The pH value showed a positive correlation with the number of Chlorella sp. cells, while water temperature, EC, air temperature, and relative humidity showed a negative correlation. Chlorella sp. from the traditional cultivation method showed the average cell count was 6.915×10⁵ cells/ml, the average pH was 6.86±0.56, the average EC was 0.53±0.07 mS/cm, and the average water temperature was 30.59±1.51 °C. Water temperature, pH, and air temperature showed a positive correlation with the number of Chlorella sp. cells, while EC and relative humidity showed a negative correlation.

Upcycling Waste Water Sludge for Preparing Clay pellets as Plant Grow Material

Phichamon Noisuwan — 2026-01-20

This research was upcycling waste sludge for preparing the growing media expanded clay from wastewater sludge including zinc sulfide together with clay. The effect of the ratio of wastewater sludge to clay was studied at 50:50, 40:60, 30:70 and 0:100% wt. and the effect of the calcined temperature at 700, 800, 900 ºC for 30 minutes on the density and percentage of water adsorption of the prepared growing material were studied. The experimental results showed that every ratio of wastewater sludge to clay had a higher percentage of water adsorption than clay pellets form clay. This was because of zinc sulfide waste water sludge have high porosity, which can be observed from scanning electron microscopy (SEM) images. The effect of calcined temperature showed that the temperature did not affect the density of the clay pellets. Moreover, it was also found that zinc sulfide still contained in the expanded clay after calcination from the EDX result. The results of the experiment were concluded that the optimized condition prepared expanded clay pellets with waste water sludge was 50:50 %wt. ratio of waste water sludge to clay at 800°C of calcination temperature. By this optimal condition, the expanded clay pellets had density of 1.97 g/cm³, water adsorption of 17.5%, pH 5.7 and 412ppm zinc content from zincon assay from leaching test. The estimation cost of expanded clay pellets with waste water sludge at the optimal condition was also calculated, resulting 23 bath/kilograms.

Thailand SET50 Simulation with Multivariate Gaussian Mixture Hidden Markov Model

Akara Kijkarncharoensin — 2026-01-20

การลงทุนในตลาดทุนจำเป็นต้องพิจารณาทั้งอัตราผลตอบแทนและความเสี่ยงที่เกิดกับการลงทุน การจำลองการแจกแจงราคาของสินทรัพย์ในช่วงเวลาข้างหน้าเป็นประโยชน์ต่อนักลงทุนเพราะสามารถทำนายทั้งอัตราผลตอบแทนและความเสี่ยงที่อาจเกิดขึ้น บทความนี้นำแบบจำลองมาร์คอฟซ่อนเร้นผสมแบบเกาส์ชนิดหลายตัวแปรมาจำลองดัชนี SET50 รายวันตั้งแต่ต้นเดือน ธ.ค. 2564 ถึงปลายเดือน ม.ค. 2567 โดยผลลัพธ์ที่สังเกตได้ซึ่งอยู่ในรูปแบบอนุกรมเวลาเป็นเวกเตอร์สามมิติของอัตราผลตอบแทนที่วัดจากราคาเปิดไปยังราคาปิดราคาสูงสุดและราคาต่ำสุดภายในวันเดียวกัน งานวิจัยนี้เปรียบเทียบการแจกแจงดัชนีราคาวันสุดท้าย ซึ่งจำลองตามแบบจำลองมาร์คอฟซ่อนเร้นผสมแบบเกาส์ชนิดหลายตัวแปรกับชนิดตัวแปรเดียว ผลการจำลองดัชนีราคาในหนึ่งปีข้างหน้าจำนวน 100,000 เส้นทาง ยืนยันความถูกต้องในผลการทำนายดัชนี SET50 โดยค่า MAPE ของแบบจำลองมาร์คอฟซ่อนเร้นผสมแบบเกาส์ชนิดหลายตัวแปรมีค่าเพียง 1.7409 เทียบกับ 2.7261 ของแบบจำลองชนิดตัวแปรเดียวการทดสอบ Wilcoxon Rank Sum ยืนยันการแจกแจงที่ต่างกันในดัชนีที่จำลองขึ้นทั้งสองแบบด้วย p-value< 0.001 นอกจากนี้การทดสอบ Kruskal-Wallis แสดงว่าในช่วงข้อมูลที่ทดสอบนั้นแบบจำลองมาร์คอฟซ่อนเร้นผสมแบบเกาส์ปราศจากอคติด้านบวกอย่างที่พบในแบบจำลองบราวน์เรขาคณิตทั้งหนึ่งมิติและหลายมิติ

Waste Reduction and Efficiency Enhancement in Ceramic Contains Production Process Using Lean Concepts

Thongchai Pokaw — 2026-01-20

The purpose of this research is to study and analyze problems in the workplace. The project uses the 7 principles of waste and finds problems and proposes solutions to improve the ceramic container production process by applying the lean concept with the goal of reducing waste and optimizing the ceramic container production process. By increasing the thickness of the fracture risk area and designing the experiment using the Taguchi method. Find the best parameters to increase process efficiency, with a Cpk of 2.02 and a Ppk of 3.89 are very good. The results showed that the waste was reduced from 43.11% to 13.21% and the efficiency of the production process increased from 56.89% to 86.79%.

Fuel Supplier Selection in Foam Packaging Production Using Analytic Hierarchy Process (AHP) : Case Study of Supboonma Packaging Part., Ltd

Jiranan Pimdee — 2026-01-20

In this research, the analytical hierarchy process is applied to select the fuel supplier in the production process of foam packaging. The evaluation factors include price, quality, punctuality, reliability, cooperation and service. The decision-making is based on the weight scores calculated by the analytical hierarchy process. According to the research results, the factors can be prioritized from most to least as follows: quality > punctuality > reliability > price > cooperation and service, with the weight scores of 0.43, 0.23, 0.19, 0.08, and 0.07, respectively. When considering the weight score of each fuel supplier, it is found that the fuel supplier no.1 gets the highest weight score of 0.61, compared to other suppliers, indicating that the fuel supplier no.1 can provide products that meet the company’s needs the most, and it is therefore the best choice. This research can be used as a guideline or a tool to help the company make systematic decision.

Applied Failure Modes and Effects Analysis for Improve Maintenance System for Yarn Twisting Machine: A Case Study of Yarn Manufacturing

Sawitree Phieboolsilapa — 2026-01-20

This research aims to apply Failure Mode and Effects Analysis (FMEA) to reduce the risk of machine failures during operation, improve the maintenance system, and minimize waste in the yarn twisting production process. The examination of defect data from the case study company revealed that the major defects were dirty yarn, fuzzy yarn, and crossed threads. A fishbone diagram was used to analyze the causes and effects of these issues. After identifying the failure modes and their impacts, the Risk Priority Number (RPN) was calculated. High-risk defects were prioritized for improvement. The main area identified for improvement was the maintenance system, which was enhanced using Total Productive Maintenance (TPM) techniques, specifically Autonomous Maintenance (AM) and Focused Improvement (FI). As a result, the defect rate decreased from 1.18% to 0.39%, representing a 66.95% reduction in defects.

Analysis of Factors Influencing Mechanical Properties of Recycled Polypropylene/Tea Waste Composites Using Factorial Experimental Design

Anuchit Khongrit — 2026-01-20

This study aimed to analyze the influence of key factors on the mechanical properties of recycled polypropylene/tea waste composites using a General Factorial Design experiment. The research evaluated the effects of tea waste type (Thai tea and green tea), polypropylene- graft-maleic anhydride (PP-g-MA) content, and thermoplastic elastomer (TPE) content on yield strength, tensile strength, elastic modulus, elongation percentage, impact strength, and hardness. Analysis of Variance (ANOVA) and quantitative effect analysis revealed that all three factors had statistically significant impacts on the composites' mechanical properties. Specifically, tea waste type significantly influenced hardness and elastic modulus, while PP-g-MA positively affected the yield strength, tensile strength and elastic modulus, and TPE enhanced impact strength and elongation percentage.

The contour plot analysis provided insights into the relationship between factors and mechanical properties, aligning with the main effects analysis results. No significant interactions were found between tea waste types and PP-g-MA or TPE content for most mechanical properties, except for elastic modulus and hardness. Regression coefficient analysis and linear regression for mechanical properties prediction showed moderate predictive capability, with determination coefficients ranging from 47.29% to 67.77%. Using the desirability function optimization method, the formulation containing green tea waste and 5% PP-g-MA without TPE achieved the highest composite desirability of 0.90, indicating the best balance of mechanical properties. Although adding 5% TPE significantly improved impact resistance and elongation percentage, it reduced the maximum tensile strength. This research suggests that the material is suitable for applications not requiring high strength, making it appropriate for furniture manufacturing or home decoration such as garden and landscape decoration, wall or ceiling panels, and shelves or storage cabinets with light load-bearing requirements.

Influence of PA12 Filament Conditions and Printing Parameters on Mechanical Properties of FDM 3D Printing Parts

Manoch Numfu — 2026-01-20

This research investigates the moisture conditions in nylon filaments and the influence of printing parameters on the mechanical properties of 3D-printed parts. The findings provide guidance for users in selecting and preparing nylon filaments before 3D printing. The study revealed that printing with low-moisture nylon filaments resulted in higher tensile strength. Specifically, nylon filament with 0% moisture content exhibited the highest tensile strength at 54.05 MPa, while filaments with moisture levels of 1.63% and 3.17% showed progressively lower tensile strengths. Adjusting the melting temperature and printing speed can enhance tensile strength. For nylon with 0% moisture, setting the melting point to 260°C and the printing speed to 30 mm/s resulted the best tensile strength. Similarly, nylon with 1.63% moisture required the same settings, while nylon with 3.17% moisture performed better at a melting temperature of 300°C and a speed of 45 mm/s. Additionally, moisture content significantly affected impact resistance, with higher moisture levels leading to reduced impact strength. Nylon with 0% moisture demonstrated the highest impact resistance at 17.18 kJ, which decreased with increasing moisture content. Adjusting the melting temperature and printing speed can slightly improve impact resistance, particularly for high-moisture filaments. Reducing the melting point to 260°C and increasing the printing speed to 60 mm/s was recommended for such cases. The findings of this study offer practical guidelines for optimizing 3D printing parameters when using nylon filaments with varying moisture levels, ensuring desirable mechanical properties in 3D-printed parts.

Assessment of Carbon Sequestration and Income Analysis from Carbon Credit Sales in Rubber Plantations According to the Age of Rubber Trees

Urairat Rattanavijit — 2026-01-20

The purpose of this study is to evaluate the carbon sequestration of monoculture rubber trees at each age stage and to analyze the income generated from the sale of carbon credits for these trees. The study area consists of five rubber plantations located in the Na Sarn and Na Dern sub-districts, including Khuan Sri sub-district in Ban Na Sarn district and Ban Na sub-district in Ban Na Dern district. In this study, the ages of the rubber trees examined are 0-5 years, 6-10 years, 11-15 years, 16-20 years, and 21 years and older and study period an april to December 2024.The study found that the carbon sequestration for rubber trees aged 0-5 years totaled 18.87 tons of CO₂ equivalent, amounting to 11,324.13 baht. For trees aged 6-10 years, the total carbon sequestration was 71.77 tons of CO₂ equivalent, worth 43,063.96 baht. In the 11-15 years age group, the total was 90.48 tons of CO₂ equivalent, equivalent to 54,289.43 baht. For trees aged 16-20 years, the total carbon sequestration reached 96.77 tons of CO₂ equivalent, amounting to 58,061.16 baht, while for trees aged 21 years and older, it was 128.28 tons of CO₂ equivalent, valued at 76,965.34 baht. Growing rubber not only generates income for farmers but also provides additional revenue from the sale of carbon credits and helps reduce carbon dioxide emissions. The study results contribute to sustainable rubber cultivation practices and promote effective economic and environmental development.

Enhancing Machinability of Hardfaced JIS-FC25 Gray Cast Iron: Coolant Application and Its Trade-offs

Niwat Mookam — 2026-01-20

This study aimed to investigate the machinability of hard-faced layers on JIS-FC25 gray cast iron, which were deposited in three layers using the shielded metal arc welding (SMAW) process. The experiments were conducted under two conditions: dry milling and wet milling using a coolant composed of oil and water in a 1:20 ratio. The milling parameters were kept constant with a cutting depth of 1 mm, spindle speed of 800 rpm, and feed rate of 100 mm/min. The experimental analysis focused on chip morphology, tool wear (flank wear), and the surface roughness of both the cutting edge and the machined workpiece. The results indicated that coolant application improved chip length and consistency, reduced friction, and enhanced lubrication during the milling process. However, in long-distance milling operations, wet milling led to accelerated tool degradation due to thermal cycling effects. In contrast, dry milling exhibited more stable tool wear and lower surface roughness over extended cutting distances. The findings suggest that dry milling is more suitable for long cutting operations as it minimizes tool wear and maintains better surface quality.Therefore, the selection of milling conditions should be tailored to match the specific requirements of real-world applications.