Journal of Applied Research on Science and Technology (JARST)

Effectiveness of separated ICR for a wheeled skid-steering robot

Ditsakorn Wanichratanagul — 2024-11-28

The skid-steering robot has gained popularity due to its mechanical simplicity and robustness, making it a preferred choice in various applications. However, this configuration is prone to slip during turning maneuvers, resulting in inaccurate trajectory prediction using the conventional differential drive kinematic model. The separated instantaneous centers of rotation (ICRs) approach has been proposed to address this issue and mitigate slips experienced during turns. Compared to the computer simulations, this study investigates the trends of the separated ICR approach on the trajectory error using a real-world robot across different terrains in low dynamic conditions. The findings reveal that the effectiveness of the separated ICR approach in compensating for slip varies depending on the turning radius. Specifically, the approach is less effective with smaller turning radii and vice versa. Surprisingly, the terrain type does not significantly impact the effectiveness of the separated ICRs approach, suggesting that its performance is more closely linked to the turning radius than to the terrain conditions. Although the simulation method outlined in this research struggles with precise surface roughness estimation, it demonstrates consistent skid behavior, indicating the potential utility of separated ICRs for skid-steering robots. To enhance the accuracy of computer simulations, a deeper exploration of terrain surface conditions is necessary. Nonetheless, the implementation of separated ICRs on our four-wheel mobile robot shows promising results, underscoring the viability of using separated ICRs to improve the performance of skid-steering robots in various settings.

Design of a two-seater seaplane wing spar structure with composite materials

Phacharaporn Bunyawanichakul — 2024-12-02

A two-seater, mono-wing seaplane was initially developed for survey and rescue operations, with an empty weight of 470 kg and a maximum takeoff weight of 650 kg. Fiber-reinforced composite materials, consisting of fiber reinforcement and thermosetting polymer, were used in this airframe to reduce weight because the structural properties can be customized by adjusting the orientation of the fiber fabric layup and removing redundant material, which is impossible with metal. This paper presents a comprehensive overview of the design process for the aircraft's primary I-beam wing spar, employing composite material. Before conducting design calculations, it is critical to consider the variability of characteristics of composite materials caused by fabrication conditions such as temperature, humidity, and defects. As a result, it is imperative to conduct thorough testing of carbon fiber-reinforced composites following many different testing requirements. The coupon tests capture critical characteristics such as strength, stiffness, and Poisson's ratio across several orientations. The wing spar I-beam structure was subsequently developed with three primary considerations: stiffness (maximum deflection), strength, and stability (structural buckling). Following preliminary sizing of the I-beam wing spar, a simple initial layup was recommended, with primary loading in each component. The initial design was then subjected to a more detailed calculation using classical lamination theory, which took into account distributed load along the wing, spar taper, ply-drops along the span, and composite layup guidelines in order to reduce structural weight while ensuring the main spar's ability to withstand operational loads effectively. The calculating results show that the spar with an optimized composite design has a lighter weight than the original design by around 43%, while it can withstand the same loads with no analytical failure.

Age-dependent mathematical models of ligaments and tendons

Ratchada Sopakayang — 2024-12-06

Understanding the internal structure and the underlying physical mechanisms governing the mechanical properties of ligaments and tendons, particularly the elastic modulus, across different stages of life is critical for enhancing tissue strength during growth, maturation, and aging. This knowledge is essential not only for preventing tissue failure in older adults but also for advancing the development of biomaterials that can substitute or augment ligament and tendon function across all age groups. Despite the significance of this area, a comprehensive, mechanistic understanding of the relationship between structural changes and mechanical properties over time remains largely unexplored. To date, there is a lack of detailed studies that elucidate the physical mechanisms involved in these age-related changes. The absence of such mechanistic insights highlights a significant gap in the literature, necessitating further investigation. Therefore, this research delves into the age-dependent structural and mechanical property changes in ligaments and tendons, emphasizing both growth and mature phases. Utilizing a comprehensive approach, we have developed new mathematical models that directly correlate the growth of collagen in fibrils with the increasing elastic modulus in the fibers of ligaments and tendons over time. By integrating experimental data from mouse tail tendons in published work and conducting simulations, we have observed that the cross-sectional area of collagen in fibrils and the elastic modulus of a collagen fiber increase rapidly during the growth phase and stabilize during the mature phase. Our proposed models effectively describe the trends in collagen growth and the elastic modulus of fibers in ligaments and tendons over different ages, exhibiting consistency with experimental data. Through detailed analysis, we elucidate the mechanistic relationship between collagen growth and the elastic modulus of fibers as they age. This comprehensive approach significantly enhances our understanding of the age-related structural and mechanical property changes in connective tissues, providing a robust framework for future investigations.

Effects of drilling parameters on drill bit wear of ASTM A36 steel

Chutimon Makee — 2024-12-11

Drilling is a crucial process in metal manufacturing, with drill bits being key tools for creating holes in workpieces. During drilling, wear of the drill bits occurs inevitably. Several factors affect the wear of drill bits, such as materials, workpieces, and drilling parameters. The impact of these parameters on wear is investigated to understand the effects of drilling parameters on drill bit wear. This study used a diameter of 6 mm of uncoated high-speed steel drill bits to create the hole with 30 mm depth on ASTM A36 steel. The drilling was performed utilizing the DMG Mori DMU-50 5-axis drilling machine at three different levels of spindle speed (800, 1100, and 1400 rev/min) and feed rate (120, 135, and 150 mm/min). The sensor force dynamometer measured the thrust force and the cutting torque during drilling. However, many types of wear occur on drill bits during drilling. This research investigates only flank wear on the cutting edge of drill bits. The flank wear on the drill bits was measured with the overlap image technique using an Olympus SZ61 stereo microscope with a C-P3 OPTIKA digital camera. The results showed that adjusting drill parameters to increase the feed per revolution may result in a higher drill bit flank wear rate. Additionally, to quantify the wear of the drill bit based on the number of holes drilled, both the feed per revolution and the cutting distance per hole must be considered.

Investigation of propeller configuration effects on the flight stability of unmanned aerial vehicles

Nutdanai Chompoosri — 2024-12-26

This study investigates the flight stability of unmanned aerial vehicles (UAVs) by comparing two-, three-, and six-blade propellers. The experiment uses a self-made drone with a 3D-printed polylactic acid (PLA) frame and an Arduino-based flight control system to create an efficient UAV prototype. The flight tests are conducted in a controlled environment, eliminating flight confounders such as wind and temperature, and the three types of propellers are of similar size. Stability was assessed by measuring deviations in the drone’s X and Y axes while hovering within ±30 degrees, and standard deviation (SD) was calculated to quantify variability. The tests revealed that propeller count significantly impacts stability and overall performance. The three-blade propeller provided the best stability, with the smallest SD in the X-axis at 10.85 and Y-axis at 11.85, and showed the least deviation over ±30 degrees during take-off and flight. While the 2-blade propeller has the least stability in flight, with a value of 15.08 in the X-axis and 16.3 in the Y-axis, showing a deviation exceeding ±30 degrees several times throughout the test, the 6-blade propeller demonstrates intermediate performance, with a value of 12.71 in the X-axis and 15.57 in the Y-axis, which is more stable than the 2-blade propeller but still less stable than the 3-blade propeller. The results of this study provide UAV design data by studying the factors in selecting propellers with different numbers of blades for drones, presenting information on the importance of propeller selection for drone flight performance and stability. The results of this study can be applied to various drone applications, such as aerial photography, agriculture, or industry. Finally, in the future, other factors are expected to affect the differences in the number of blades regarding energy efficiency and flight duration.

Increasing the value of jackfruit cobs as agricultural waste materials for syrup production by enzymatic hydrolysis using pectinase and cellulose

Kulthida Longern — 2024-12-26

This research aimed to investigate the optimal working conditions for pectinase and cellulase, evaluate the quality of jackfruit cob syrup, and assess its physical and chemical properties and consumer acceptance. The study began with exploring the optimal conditions for syrup production from jackfruit cobs. The factors studied were the amount of pectinase in 3 levels: 0.04, 0.06, and 0.08%; the amount of cellulase in 2 levels: 0.1 and 0.2%; and the incubated temperature in 3 levels: 40, 45, and 50 °C; the incubated time in 3 levels: 30, 90, and 150 minutes. All 54 conditions were obtained in Factorial experiments in Completely Randomized Design (CRD). The physical and chemical properties were analyzed, and the optimal conditions were determined through hierarchical clustering, along with evaluating the physical and chemical properties and consumer acceptance. It was found that the optimum conditions for extraction of jackfruit cob juice include 0.08% pectinase, 0.2% cellulase, incubated temperature at 40 °C, and a curing time of 90 minutes, respectively. The properties of jackfruit cob syrup were as follows: brightness (L*) of 22.77 ±0.04, (a*) of -0.74 ±0.06, and (b*) of 9.16 ±0.43. The light transmittance was 1.99 ±0.01, viscosity was 14.00 ±0.05 centipoise, and pH was 4.75 ±0.10, indicating prebiotic properties. The overall liking score was 7.96. After being informed about the nutritional benefits of jackfruit cob syrup, 85.00% of consumers indicated a willingness to purchase the product. It will add value to the waste jackfruit cob in agriculture to 86 baht per kilogram. Therefore, jackfruit cob syrup is a value-added product that enhances the utilization of agricultural by-products, reduces agricultural waste, and meets consumer demand for healthy food options.

Exploring the design and construction techniques of post-tensioned slabs

Thanadet Sriprasong — 2025-02-18

This research aims to: 1. Study the post-tension concrete floor type. 2. Study the case study of the building construction process using post-tension concrete floors by studying the plans and construction steps of post-tension concrete floors from studying the manuals and documents for the construction of prestressed concrete floors, applying the knowledge gained from working and learning on-site to understand the characteristics, types, and plans of prestressed concrete floors and the construction steps of prestressed concrete floors. The results of this research provide information on the plans and steps in the construction of post-tension concrete floors, construction supervision, management to meet the specified time frame, various construction problems and solutions, and the development of knowledge and skills in construction supervision for future use. In conclusion, understanding the work process, construction process control methods, and inspection of various post-tension concrete floor constructions can increase work efficiency and reduce labor costs, time, and damage costs, such as contracting parties for breaches of contract. It was found that the advantages of the post-tension floor system are more floors at the same building height and less wind load at the same number of floors because it can improve long-term performance compared to traditional reinforced concrete and beam-slab systems. In addition, factors that affect the useful labor utilization ratio consist of 4 factors: complexity of building design, work items or work steps that make work difficult; use of appropriate tools and machinery to facilitate work and reduce labor waiting time; use of various innovations or substitute materials to help reduce time in work steps; arranging a team of workers that is appropriate for the size and type of work. These factors directly affect the ratio of useful workers. Results from this research Can be used to improve construction processes and inspection, Including selecting concrete materials to increase efficiency.

Behavioral analysis of two-dimensional difference equations in the third quadrant

Kanmanee Kitsasom — 2025-02-20

Piecewise linear systems of difference equations have gained significant attention for their ability to model complex behavior in population dynamics, economics, and electronics fields. Despite their simple structure, these systems can exhibit diverse behaviors, including convergence to equilibrium points, periodic solutions, and chaotic outcomes under specific conditions. This paper investigates the long-term behavior of a specific piecewise linear system of difference equations. The primary goal is understanding how initial conditions and parameter values influence the system's behavior. The research focuses on identifying and analyzing equilibrium points, periodic solutions (cycles), and the conditions under which these behaviors occur. Building on previous work by Grove et al., we study a family of two-dimensional difference equations containing absolute value terms. The analysis focuses on initial conditions in the third quadrant, divided into three distinct regions: A, B, and C. The behaviors within each region are explored to characterize the system's outcomes. Region A: The system converges to an equilibrium point. The number of iterations required for convergence varies depending on the sub-region. Region B: The system converges to an equilibrium point in exactly two iterations. Region C: The system exhibits more complex behaviors, with potential outcomes including convergence to a 4-cycle or an equilibrium point. Behavior in this region suggests that initial conditions may lead to one of two prime period-4 cycles. Regions A and B consistently lead to equilibrium points, while Region C displays more varied outcomes, including periodic cycles. These findings emphasize the complexity of piecewise linear systems and stress the need for further research to fully understand the behaviors in Region C.

Development and optimization of a fresh lotus embryo piercing machine

Sunan Parnsakhorn — 2025-03-03

Crispy lotus seeds were a healthful snack suitable for all ages and commonly available in modern commerce outlets. The production process requires removing the lotus embryo before crisping. Traditionally, manual labor separated the embryo from the lotus seeds. Operators use specialized equipment to separate the lotus embryo from the lotus seeds. This requires a lot of work time and may cause injury to the operator due to the equipment used. Many research works have created machines to help process lotus seed products, but their performance is lacking. This research focused on creating and developing a fresh lotus seed embryo removal machine to improve precision and reduce seed damage during extraction. The prototype machine included a frame construction, a seed feeding tray, a piercing unit, and a PLC control panel. Two types of needles are used to pierce the lotus embryo. The sharp needle produced the best results when tested with sharp and blunt needles at piercing speeds of 16.7, 25.0, and 33.3 mm/s. The findings revealed a 91.7% success rate in embryo removal, 13.9% seed splitting, 2.8% seed damage, a processing capacity of 0.7 kg/hr, and an energy usage of 0.4 kW-hr. Economic engineering research revealed that employing the lotus embryo removal machine for 1,440 hours per year resulted in an average cost of 83.3 THB per kilogram, a 26.4-month payback period, and a breakeven threshold of 1,233.3 hours per year (863.3 kg per year). The prototype performed at least twice as quickly as manual labor (0.3 kg/hr).