Academic Journal of Industrial Technology Innovation

EFFECTS OF OIL PALM BIOMASS TYPE AND CONTENT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF RECYCLED POLYPROPYLENE COMPOSITES FOR WOOD SUBSTITUTE APPLICATIONS

Kuammar Karama, Theerapong Kaewsomthong, Sopida Jornden, Uraiwan Sookyung — Mon, 31 Aug 2026 00:00:00 +0700

This research aimed to enhance the value of recycled polypropylene (PP) by incorporating oil palm biomass, namely palm kernel shell (PM) and oil palm fiber (OPF), to develop composite materials for wood substitute applications in furniture manufacturing. The composites were prepared using an internal mixer at 170 °C and 60 rpm, followed by hot-press molding at 170 °C for 20 min. The effects of biomass type and content on the physical and mechanical properties of the composites were investigated, including density, water absorption, thickness swelling, modulus of rupture (MOR), modulus of elasticity (MOE), and screw withdrawal strength. The results showed that increasing PM and OPF contents led to higher composite density and water absorption. The PP60PM40 formulation exhibited the highest density of 1.03 g/cm³ and the highest MOR among the composite formulations at 43.81 MPa. The PP60PM20OPF20 formulation showed the highest thickness swelling of 1.79%. Nevertheless, all composite formulations exhibited water absorption below 0.35% and thickness swelling below 2%, indicating excellent dimensional stability. Comparison with Thai Industrial Standard TIS 966-2547 and Japanese Industrial Standard JIS A 5905 revealed that most formulations satisfied the requirements of JIS A 5905 in terms of density, thickness swelling, MOR, and MOE. The findings demonstrate that recycled polypropylene reinforced with oil palm biomass has considerable potential for the development of sustainable wood substitute materials, while simultaneously adding value to agricultural residues and supporting circular economy practices.

COMPARISON OF ESTIMATION METHODS FOR ULTIMATE BEARING CAPACITY OF DRIVEN PILES BASED ON NON-FAILED LOAD TESTS

Phattadon Thongduang, Panu Promputthangkoon — Mon, 31 Aug 2026 00:00:00 +0700

Pile load testing is commonly conducted using test piles to evaluate pile behavior under actual soil conditions. In practice, these tests are often performed only up to a specified proof load level at which the ultimate failure point is not clearly observed, thereby requiring interpretation methods to estimate the ultimate bearing capacity. This study aims to assess and compare methods for estimating the ultimate bearing capacity of driven piles and to propose an approach for joint interpretation of the results. Field data from five test piles in the Highway No. 4–Sadao Border Checkpoint 2 Interchange Project (Section 1), Songkhla Province, were analyzed. The dataset comprised soil investigation results, pile driving records, and field static pile load test results. The evaluation comprised four approaches: (1) static method, (2) interpretation of static load test results using various methods, (3) a proposed combined method based on selected interpretation methods, and (4) dynamic method. The results indicated that the estimated ultimate bearing capacities varied according to the analytical principles and input data of each approach. The static analytical method generally produced relatively low and conservative estimates, ranging from 122.75 to 142.95 tons. The proposed combined method produced intermediate estimates ranging from 132.46 to 177.84 tons serving as a complementary approach when used with other methods. Dynamic methods yielded higher estimates, reflecting the influence of energy assumptions and pile driving conditions. the Hiley formula produced values ranging from 206.54 to 273.67 tons, whereas the Engineering news formula yielded values ranging from 181.82 to 210.53 tons. These findings indicate that the ultimate bearing capacity of driven piles should not be evaluated using a single method alone. Instead, multiple methods should be considered together to support engineering judgment under the limitations of field data.

COMPARISON OF TIME-DOMAIN VIBRATION SIGNATURES OF A MINI CNC SPINDLE UNDER DIFFERENT WOOD CARVING TOOL PATHS

Saree Nulong, Tanarat Rattanakool, Kantamon Sukkrajang, Weerachai Madtharak — Mon, 31 Aug 2026 00:00:00 +0700

This study aimed to compare the time-domain vibration signatures of a mini-CNC spindle under different wood-carving tool paths and to investigate the effect of signal smoothing on preserving the characteristics of the original vibration signal. Hopea wood was used as a workpiece, and a 3 mm two-flute HSS cutter was employed. The cutting parameters were fixed at a spindle speed of 10,000 rpm, a feed rate of 150 mm/min, and a cutting depth of 5 mm. Three carving tool paths were investigated: straight line, circle, and triangle. Acceleration vibration signals were measured at the spindle separately in the axial, horizontal, and vertical directions. Each experimental condition consisted of 2,048 data points acquired over 0.080 s. The signals were analyzed using RMS, Peak, Peak-to-Peak, and coefficient of variation (CV). Signal smoothing was performed using Moving Average (MA) and Simple Exponential Smoothing (SES), while MAE, RMSE, and NRMSE were used to quantify the differences between the raw and smoothed signals. The results showed that the straight-line tool path produced the highest RMS values in all three measurement directions, with values of 7.875, 8.120, and 8.644 g in the axial, horizontal, and vertical directions, respectively. Its CV values were relatively low, ranging from 3.701% to 11.532%, indicating a high but comparatively stable response to vibration. In contrast, the circular tool path exhibited greater signal variability, with CV values ranging from 46.778% to 72.974%. The triangular tool path showed relatively stable vibration in the axial and horizontal directions but high variability in the vertical direction, with a CV of 58.617%. The smoothing-error metrics reflected the degree of deviation introduced by signal smoothing and were therefore interpreted as measures of signal distortion rather than as sole criteria for selecting an optimal smoothing method. The results demonstrate that different tool paths and measurement directions produce distinguishable time-domain vibration characteristics in the mini-CNC spindle.

LABORATORY-SCALE STUDY OF BIOGAS COMPOSITION AND HEATING VALUE FROM CO-DIGESTION OF WATER HYACINTH AND CATTLE MANURE

Mon, 31 Aug 2026 00:00:00 +0700

This study investigated the basic characteristics of water hyacinth and cattle manure and compared the composition and volumetric heating value of biogas obtained from different co-digestion ratios. The results were intended to provide preliminary laboratory-scale information for subsequent pilot-scale development and validation. Experiments were conducted using 5-L anaerobic digesters with five water-hyacinth-to-cattle-manure ratios on a dry-weight basis: 100:0, 75:25, 50:50, 25:75, and 0:100. The resulting biogas was analyzed for methane (CH₄), carbon dioxide (CO₂), oxygen (O₂), and hydrogen sulfide (H₂S). Based on three gas-composition measurements, the 50:50 ratio produced the highest mean methane fraction under the conditions investigated, at 60.80 ± 0.66%, whereas the corresponding mean CO₂, O₂, and H₂S values were 36.50 ± 0.46%, 1.90 ± 0.10%, and 141.00 ± 3.61 ppm, respectively. Based on its methane fraction, the calculated volumetric heating value of biogas from the 50:50 treatment was 21.77 MJ/m³, the highest among the investigated ratios. A separate scenario-based energy and economic assessment was also performed by assuming a future application-scale biogas production rate of 1.00 m³/day; this value was not measured from the 5-L laboratory digesters. Under assumptions of an initial investment of 18,000 THB, annual operating and maintenance costs of 1,000 THB, and gross annual energy savings of 4,701.20 THB, the annual net cash flow was 3,701.20 THB and the simple payback period was approximately 4.86 years. These laboratory-scale results indicate that the 50:50 ratio provided a comparatively high methane fraction and volumetric heating value under the conditions tested. Measurements of cumulative biogas production, specific methane yield, process stability, and pilot-scale performance are required before conclusions regarding household- or community-scale applicability can be made.

OPTIMIZE SUPPLIER SELECTION FOR PROCESSED CHICKEN RAW MATERIALS IN FROZEN FOOD INDUSTRY USING THE ANALYTIC HIERARCHY PROCESS: A CASE STUDY OF XYZ

Benchaphon Kanhamom, Piya Butsarakul, Pattanapong Praykaw — Mon, 31 Aug 2026 00:00:00 +0700

This research aims to determine the relative weights of key decision criteria and prioritize alternative suppliers for processed chicken parts in a case study of XYZ Company. The organization currently lacks a systematic evaluation system for processed chicken suppliers, leading to uncertainties in quality and raw material costs. To address this, The Analytic Hierarchy Process (AHP) was applied in conjunction with the expert judgments of five key informants within the organization. The evaluation of five main criteria revealed that product quality holds the highest priority weight (0.462), accounting for nearly half of the total decision weight and being twice as important as price (0.216), which ranked second. Meanwhile, delivery, reliability, and service exhibited comparatively similar levels of importance in the subsequent rankings, the results indicated that Supplier A is the most strategically optimal alternative, achieving the highest composite weight of 0.561, followed by Supplier B (0.276) and Supplier C (0.163). The findings of this study provide the case company with a standard decision-making tool for procurement, that reduces operational risks, but also offer a scalable model adaptable for the procurement of other raw materials to ensure long-term efficiency.

DEVELOPMENT OF ELECTRICAL SYSTEM TRAINING KIT FOR INTERNAL COMBUSTION ENGINE VEHICLE AIR CONDITIONING FOR VOCATIONAL CERTIFICATE STUDENTS

Mon, 31 Aug 2026 00:00:00 +0700

The objectives of this research were to: 1) develop a modular electrical system training kit for internal combustion engine vehicle air conditioning for vocational certificate students; 2) evaluate the appropriateness of the developed training kit; 3) compare student learning achievement in the automotive air conditioning course between the group taught using the modular training kit and the group taught via the conventional method; and 4) study student satisfaction with the learning process. The sample consisted of 40 third-year vocational certificate students from the Auto Mechanics Department at Phetchaburi Technical College during the first semester of the 2025 academic year, divided into an experimental group of 20 students and a control group of 20 students, obtained through cluster sampling via drawing lots. The research instruments comprised the modular electrical system training kit with four learning stations, active learning lesson plans, job sheets, a learning achievement test, and a satisfaction questionnaire. Statistics used for data analysis were percentage, mean, standard deviation, dependent samples $t$-test, independent samples $t$-test, and effect size calculation. The results revealed that the developed training kit and instructional packages possessed appropriateness at the highest level as rated by experts (Mean = 4.69, S.D. = 0.36). The training kit achieved an overall efficiency of 79.25/82.00, exceeding the pre-established 75/75 standard threshold. The experimental group obtained a post-test mean score of 16.40 (S.D. = 1.35), which was significantly higher than their pre-test mean score of 9.15 (S.D. = 1.42) at the .05 level (t = 22.48, df = 19, p < .001). Furthermore, the between-group comparison demonstrated that the post-test mean achievement score of the experimental group was significantly higher than that of the control group (Mean = 12.10, S.D. = 1.62) at the .05 level (t = 9.11, df = 38, p < .001), with a very large effect size (Cohen's d = 2.88, 95% CI [2.05, 3.71]). Overall satisfaction of the experimental group across all dimensions was at the highest level (Mean = 4.74, S.D. = 0.30). Additionally, the educational economic evaluation indicated that the kit required a low fabrication cost of only 28,500 Baht per unit, reducing equipment procurement budget costs by 76.25%, with a cost-effectiveness ratio of 196.55 Baht per score gain, and reducing absenteeism and dropout rates to 0.00%, effectively enhancing access to practical training tools and systematically optimizing budget expenditure.

DESIGN AND DEVELOPMENT OF A DIGITAL SERVICE PLATFORM USING LINE OFFICIAL ACCOUNT FOR COMMUNITY ENTERPRISES IN KHANOM DISTRICT, NAKHON SI THAMMARAT PROVINCE

Wachira Yangyuen, Kamonnan Chevarattanachote, Metaporn Meedate — Mon, 31 Aug 2026 00:00:00 +0700

This study aimed to (1) design and develop a digital service system via LINE Official Account for community enterprises and (2) evaluate user acceptance of the system based on the Technology Acceptance Model (TAM). A contextual review of the target community enterprises indicated that information regarding products, services, tourism, news, and contact channels was fragmented across disparate communication channels. Consequently, this study sought to develop a digital service system that consolidated these services into a single platform. The study employed Design and Development Research (DDR) and applied the System Development Life Cycle (SDLC) as the development framework, systematically encompassing requirements analysis, system design, development, testing, and refinement, while the TAM framework was utilized to assess user perceptions and system acceptance following implementation. The investigation focused on two community enterprises as case studies, comprising 17 key informants for requirements analysis, 3 information technology experts for system quality evaluation, and 60 end users for technology acceptance evaluation. Qualitative data were analyzed using content analysis, while quantitative data were analyzed using descriptive statistics, including the mean () and standard deviation (S.D.). The findings revealed that the developed system effectively integrated and presented enterprise information, products and services, tourism data, news, contact channels, and external digital services through LINE Official Account within a unified service structure. The overall system quality evaluated by the experts was at the highest level ( = 4.59, S.D. = 0.17). Overall user technology acceptance was likewise at the highest level ( = 4.64, S.D. = 0.48). Among the TAM dimensions, Perceived Usefulness yielded the highest mean score ( = 4.70, S.D. = 0.46), followed by Perceived Ease of Use ( = 4.67, S.D. = 0.48), Behavioral Intention to Use ( = 4.62, S.D. = 0.49), and Attitude Toward Using ( = 4.57, S.D. = 0.50), respectively, demonstrating that the system effectively met user needs and achieved high acceptance. The key contribution of this research is an integrated design and development framework for LINE Official Account-based digital service systems that connects requirements analysis, SDLC-based development, and TAM-based acceptance evaluation. This framework serves as a practical model for developing and evaluating digital service systems in community enterprises with diverse operational contexts, adaptable to the specific context and user requirements of each area.