Journal of Engineering and Innovation

Thermal expansion coefficient of cellular lightweight concrete

2025-06-26T14:18:48+07:00

This research studied the thermal expansion coefficient and air void content of the cellular lightweight concrete. The tests were carried out for the concrete at the design unit weight of 1600 and 1800 kilograms per cubic meter using the ratio of sand to cement 2:1 and 3:1 and adding the superplasticizer agent at 0, 0.5 and 1 percent of cement weight. The 12 designed mixes, 6 samples for each mix, a total of 72 samples were produced and cured in the air for 28 days. The thermal expansion coefficient tests were carried out according to the TI-B 101 Test Method Expansion Standard. The results shown that (1) for the cellular lightweight concrete with unit weight 1600 kilograms per cubic meter, the coefficients of expansion due to the heat are found in the range of (10.6-13.7) x10^-6 per degree Celsius and (2) for the cellular lightweight concrete with unit weight 1800 kilograms per cubic meter, the coefficients of expansion due to the heat are found in the range of (12.5-15.8) x10^-6 per degree Celsius. The air void content tests were carried out according to ASTM138 Gravimetric method. The test results for air void content showed that, at unit weights of 1600 and 1800 kilograms per cubic meter, the cellular lightweight concrete contained air voids in the range of approximately 27–32.3% and 19.2–23.8%, respectively.

Effect of fin angles of attack on heat transfer and air pressure drop in a fin-and-tube heat exchanger

2026-02-22T14:46:29+07:00

Abstract

This research investigates the effect of the angle of attack between the air and the fins on the heat transfer and air pressure drop of a fin and tube heat exchanger. Four fin angles of attack (i.e., 0°, 5°, 10° and 15°) and three fin pitches (i.e., 7.5 mm, 10 mm and 15 mm) are tested. The working fluids for testing are the water and the air, the water at 80°C with constant flow rate is 5 l/min while the air at 30° C with various velocities from 2 m/s to 10 m/s flow through the heat exchanger. The results show that the heat transfer rate and air pressure drop of all fin pitches are mainly influenced by the angle of attack and air velocity. Heat transfer and air pressure drop increase with increasing the angle of attack and the air velocity. The 15° provides significantly higher heat transfer and pressure drop than the 0° of 38.44% and 299.68%, respectively. When considering the ratio between heat transfer to pressure drop or the heat exchanger performance, it is found that increasing of both the angle of attack and the air velocity were results decrease the heat exchanger performance. It was found that at the angle 0° provided 245.01% greater performance than the angle of 15°.

Improving the performance of a banana solar drying cabinet using an automatic temperature control system with IoT-based alerts

2026-04-25T16:46:59+07:00

This research aimed to design and develop a temperature control system for a solar banana drying cabinet using a KidBright32 microcontroller together with a DHT22 temperature sensor. The system also included a notification and data display system via a smartphone application using Internet of Things (IoT) technology. An automatic curtain opening–closing mechanism was designed to control the internal temperature of the drying cabinet within an appropriate range. The system was programmed to close the curtain when the temperature exceeded 60°C and open the curtain when the temperature dropped below 55°C. The experimental results showed that the developed system could effectively maintain the temperature inside the solar banana dryer within the specified range. The system was able to display real-time data and send notifications to a mobile phone. Moreover, the system reduced the time required for opening and closing the shade curtain from an average of 45 seconds using manual operation to only 18 seconds using the automatic system. In addition, compared with traditional sun drying, the system reduced the amount of damaged bananas from an average of 38.18% to 11.82%. The dried bananas produced had more consistent quality in terms of color, aroma, taste, and texture. User satisfaction was at a very high level. The economic analysis showed that the system cost approximately 5,237 baht to build and the investment could be recovered within 4–5 months. Therefore, the developed solar banana dryer control system can improve the efficiency of the banana drying process, reduce waste, improve product quality, and is suitable for application at the household or community level.

Development of a prototype fertilizer mixer to improve productivity and reduce ergonomic risks among small-scale farmers

2026-03-01T13:02:59+07:00

This study aimed to develop a prototype fertilizer mixer for small-scale farmers and to evaluate its effectiveness in improving productivity and reducing ergonomic risks under actual operating conditions in Ban Dan Community, Ko Taeo Subdistrict, Mueang District, Songkhla Province, Thailand. The study involved 17 small-scale farming households, and manual fertilizer mixing was selected as the case study because the task required repetitive physical effort and caused worker fatigue during operation. The research process consisted of four stages: (1) pre-improvement ergonomic risk assessment using Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA); (2) the design and construction of a 200-L rotary drum fertilizer mixer powered by a 1-hp motor with an optional manual-crank mode; (3) performance testing of 15 kg fertilizer mixing under three conditions, namely manual mixing, manual-crank mixing, and motor-driven mixing, with five repetitions for each method; and (4) satisfaction evaluation involving six participants, including three experts and three actual users. The ergonomic assessment results showed that, prior to improvement, the manual fertilizer-mixing process involved a very high level of ergonomic risk, with RULA and REBA scores of 7 and 10, respectively. After the prototype had been developed, these scores decreased to 3 and 2, respectively. Regarding productivity, the average mixing time for 15 kg of fertilizer decreased from 5.12 ± 0.032 min in manual mixing to 1.17 ± 0.029 min in the manual-crank condition and 1.08 ± 0.029 min in the motor-driven condition. A one-way analysis of variance (ANOVA) indicated that the mean mixing times among the three methods differed significantly (p < 0.001). In addition, the overall satisfaction score was at the highest level, with a mean value of 4.51. The findings suggest that the developed prototype may help reduce fertilizer mixing time and physical workload under the field conditions examined in this study. However, further studies involving different fertilizer formulas, operating conditions, and larger groups of users are still required to confirm its broader applicability in community-based agricultural operations.

Analysis of location and routing for additive manufacturing logistics networks in healthcare network using a linear-normalized weighted multi-objective model

2026-05-21T11:21:49+07:00

This research aims to analyze location and optimize delivery routes for a centralized healthcare Additive Manufacturing (AM) system producing external patient-specific prostheses using Fused Deposition Modeling (FDM) technology under strict time-window constraints. A case study of 23 healthcare facilities in Phra Nakhon Si Ayutthaya Province was conducted using a deterministic model tailored for a localized problem size. The methodology first determines the optimal centroid hub using rectilinear minisum location model, followed by the development of a Multi-Objective Vehicle Routing Problem with Time Windows (MOVRPTW) model. The model simultaneously minimizes total operating cost, maximum employee work time, and carbon dioxide emissions, and is solved using an exact method. The results indicate that hospital H17 is the optimal centralized production hub. The generated Pareto optimal solution yields a routing plan utilizing 4 vehicles to distribute a total of 99 medical parts within the operational time windows (09:00 AM – 02:05 PM). The plan limits the maximum employee work time to 305 minutes and restricts carbon dioxide emissions to 105.06 kilograms, while achieving a total operating cost of 28,279 THB (averaging 285.65 THB per unit). This study supports strategic planning to enhance cost-effective and sustainable digital healthcare logistics.

Facial foam product from charcoal derived of macadamia processing waste

2026-04-08T15:40:25+07:00

This study was conducted with the objective of developing a facial cleansing foam derived from charcoal obtained from macadamia nutshells and investigating the relationship between charcoal particle size and loading concentration on the physicochemical and functional properties of the formulation. A two-factor (3 × 5) full factorial experimental design was employed, comprising three levels of particle size (0.05, 0.10, and 0.15 millimeters) and five levels of charcoal loading concentration (10, 20, 30, 40, and 50 percent by weight). The full factorial design was applied during the formulation development stage to evaluate pH, surface tension, and cleansing efficiency. The optimal formulation was subsequently selected for evaluation of skin irritation potential and user satisfaction in 40 volunteers. The experimental results suggested that both particle size and loading concentration influenced the properties of the formulation. The particle size 0.05 millimeters demonstrated superior cleansing efficiency, which was attributed to its higher specific surface area and enhanced adsorption capability. Among the tested formulations, the 20 percent by weight charcoal concentration was identified as the optimal level, yielding a mean pH of 5.3, which is appropriate for topical skin application. In addition, this formulation exhibited a surface tension within the range of 25–35 mN/m and the highest cleansing efficiency of approximately 94.8% compared with other experimental conditions. Evaluation in human subjects confirmed that the formulation was well tolerated, with only mild initial skin irritation that diminished over time. Overall user acceptance was high, with a mean satisfaction score of 8 out of 9, indicating favorable consumer response to the developed product.

Application of DMAIC for reducing concrete quantity variability in reinforced concrete structural work of single-detached house construction

2026-04-08T15:12:05+07:00

This research aims to improve the accuracy of concrete quantity estimation in reinforced concrete structural work of single-detached house construction by applying the DMAIC framework to analyze the causes of concrete quantity deviation. The study began with an analysis of construction cost data for a single-detached house with a usable area of 96 square meters. The results indicated that reinforced concrete structural work accounted for the highest proportion of total construction cost, representing 17.4% of the overall project cost. Therefore, this activity was selected as the target process for improvement. Improvement measures included the development of a standardized concrete quantity calculation form, the establishment of a checklist for reviewing construction drawings, the preparation of a work instruction for concrete quantity estimation, and the determination of an appropriate tolerance level for ordering concrete. The results showed that the deviation in concrete quantity decreased from 8.3% to 1.4%, while the concrete quantity deviation was reduced from 1.96 m³ to 0.33 m³. The findings indicate that the DMAIC-based improvement measures effectively reduced concrete quantity deviation and enhanced estimation accuracy in the case study project.