International Transaction Journal of Engineering,Management, & Applied Sciences & Technologies11/1/2019 Dulyachot Cholaseuk, Pornprom Pahubutra, "A Road Test Study on Speed Sensitive Collapsible Mechanical Speed Bump", Vol. 11(1), p1-8, Nov. 2019 Abstract
A speed sensitive collapsible mechanical speed bump is a structure of a triangular shaped profile with joints that allow the bump to fold flat. The operation of the bump relies on an all mechanical system that uses a pendulum as a speed sensor. The amount of angular motion of the pendulum varies with the speed of the vehicle passing. This determines the position of the tip of the pendulum that contacts the guide rail, which can control the pendulum to fold or to lock. The speed bump is designed to lock when a vehicle passes at speed above 8 km/hr and to fold flat at the speed below 8 km/hr. This road test version was vastly improved from the conceptual prototype. The pendulum speed sensing mechanism was separated from the locking mechanism to ensure speed sensing accuracy while improving strength in the locking position. Overall profile was scaled down to fit Thailand’s speed bump standard. Testing was conducted with six vehicles of different segments: an eco car, two compact sedans, two mid-size suv’s and a pick-up truck. The test results show that the bump response well with the transition range of 7 – 12 km/hr.
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Chanya Jiemjai, Santhanee Khruakhorn, Patcharee Kooncumchoo, "Erector Spinae Muscle Activity during Lifted People with Two Persons in Lifting Phase of Manual Human Handling (MHH)", Vol.24 No.2 April – June 2019 Abstract
The objective of this study was to determine the activity of erector spinae muscle in four techniques of lifting phase of manual human handling; two-handed seat carry, four-handed seat carry, fore-and-aft carry and chair carry. Thirty-two (16 couples) healthy young men lifted subjects weighing 60±5 kg from table heights of 50 cm and 100 cm. Surface electromyography was used to evaluate lumbar erector spinae activity during lifting. The four-handed seat carry technique had the highest average of lumbar erector spinae activity both from table height 50 cm and 100 cm. This may be due to more trunk flexion movement than in other techniques. The lowest activity of lumbar erector spinae was found in fore-and-aft carry and chair carry techniques. Moreover, lifting from table height 50 cm had more lumbar erector spinae muscle activity than lifting from table height 100 cm in 3 techniques (two-handed seat carry, four-handed seat carry and fore-and-aft carry). The highest activity of lumbar erector spinae muscle in the four-handed seat carry technique indicated risk of low back pain during lifting, especially lifting people from a table height of 50 cm. Lower lumbar erector spinae muscle activity in fore-and-aft carry and chair carry techniques indicated safer they are safer techniques for lifting. Charoenporn N, Outama A, Kaewdok T, Earde P, Kooncumchoo P, "Maximum Acceptable Weight of Lift in Adolescence Aged 15 to Less Than 18 Years Old", Proceedings of the 20th Congress of the International Ergonomics Association (IEA 2018), p778-788 Abstract
By Convention No. 138 specifies the minimum age for working children which it must not be lower than the age of completing compulsory education and lower than 15 years old. The allowable work for working children must not be harmful to children’s health, must be safe and not against good morals. Manual material handling is common tasks can be found in many conditions of working children aged 15 to less than 18 years old, especially lifting tasks. The lifting tasks may exceed the children’s capacity and may lead them to problems of accumulative fatigue, musculoskeletal disorders and other health effects in the future. This study was conducted not only to determine what maximum weight is accepted by the children but also to compare its’ results with NIOSH lifting equation whether suitable for working children or not. This research experiment get permission and approval from Thammasat University Research Ethics Subcommittee 3. The study of lifting tasks by simulating works in laboratory and applying psychophysical criteria shows that the maximum acceptable weight is significantly different between boys and girls. Increasing lifting frequency can significantly affect to the MAWL. The MAWL based on psychophysical criterion seems not to be different when lifting frequencies more than 1 lift/minute. The RWL (at origin) calculated from NISOH lifting equation based on the load constant recommended by ISO11295:2014 are higher than the MAWL of this study. It is possible using NIOSH lifting equation to assess risk of manual lifting at origin may be underestimate when applying to working children situation. วรัตถ์ สิทธิ์เหล่าถาวร, บรรยงค์ รุ่งเรืองด้วยบุญ, "การออกแบบอุปกรณ์ช่วยเดิน ที่มีระบบพยุงน้ำหนักบางส่วนสำหรับผู้ที่มีปัญหาการเคลื่อนไหวด้านการเดิน รุ่นที่ 2.0" วิศวกรรมสาร มก. ฉบับที่ 105 ปีที่ 31 กรกฎาคม - กันยายน 2561, หน้าที่ 1-10
บทคัดย่อ งานวิจัยที่นำเสนอนี้เป็นงานวิจัยเพื่อออกแบบและพัฒนาอุปกรณ์ช่วยเดินแบบพยุงน้ำหนักบางส่วนสำหรับผู้ที่มีปัญหาการเคลื่อนไหวด้านการเดินรุ่นที่ 2 สำหรับกลุ่มผู้ป่วยโรคหลอดเลือดสมอง กลุ่มผู้ป่วยโรคกล้ามเนื้ออ่อนแรง กลุ่มผู้สูงอายุ โดยผู้วิจัยได้เริ่มต้นการวิจัยและพัฒนาอุปกรณ์ต้นแบบช่วยฝึกเดินแบบพยุงน้ำหนักบางส่วนมาแล้ว 1 รุ่น โดยโครงการนี้เกิดขึ้นเพื่อแก้ไขปัญหาการฝึกเดินหลังจากที่ผู้ป่วยผ่านการฝึกเดิน หรือใช้เทคโนโลยีหุ่นยนต์ช่วยฝึกเดินมาแล้ว จนมีระดับความสามารถการเดินที่ดีขึ้นในระดับหนึ่ง ซึ่งหมายถึง ผู้ป่วยพอจะช่วยเหลือตัวเอง หรือก้าวขาได้ด้วยตัวเองได้ (ค่าระดับความสามารถของการเดิน ระดับ 2-4) หลังจากขั้นตอนนี้ผู้ป่วยจะต้องฝึกเดินให้บ่อยที่สุด โดยใช้โครงช่วยฝึกเดิน ซึ่งจะทำให้มัดกล้ามเนื้อแข็งแรง แต่ปัญหาที่เกิดขึ้นคือ การหกล้ม ซึ่งเกิดจากอุปกรณ์ไม่มีระบบพยุงน้ำหนัก และเนื่องจากผู้ป่วยมีปัญหาด้านการเคลื่อนไหวและมีความพิการหลงเหลืออยู่ ทำให้ส่งผลต่อการเคลื่อนไหวร่างกายและรูปแบบการเดิน ทำให้เสี่ยงต่อการหกล้มเพิ่มขึ้นเป็น 2-3 เท่า เมื่อเทียบกับประชากรกลุ่มอายุเดียวกัน ซึ่งการแก้ไขปัญหาการหกล้มได้นั้น ก็คือการฝึกเดินเพื่อช่วยเสริมสร้างความแข็งแรงของกล้ามเนื้อ และป้องกันการหกล้ม ซึ่งวิธีนี้ได้รับการพิสูจน์ทางวิชาการแล้วว่าช่วยป้องกันการหกล้มได้ดีที่สุด งานวิจัยชิ้นนี้มุ่งเน้นการพัฒนาต้นแบบอุปกรณ์ช่วยฝึกเดินรุ่นที่ 2 เพื่อแก้ปัญหาที่กล่าวมา โดยตัวอุปกรณ์ที่ออกแบบมีส่วนที่สำคัญ คือ ระบบพยุงน้ำหนักบางส่วน แบบไดนามิกส์ โดยใช้แก๊สสปริงทำหน้าที่พยุงน้ำหนักเพื่อช่วยพยุงน้ำหนักบางส่วนของผู้ป่วย โดยปรับระดับแรงพยุงน้ำหนักได้โดยการปรับมุมเอียงทิ่ใช้ติดตั้งแก๊สสปริง จากผลการทดสอบอุปกรณ์ต้นแบบ พบว่า อุปกรณ์สามารถพยุงน้ำหนักตัวผู้ป่วยได้ตามที่ออกแบบไว้ และสามารถเพิ่มประสิทธิภาพการฝึกเดิน ช่วยเหลือผู้ป่วยให้การฝึกเดินด้วยอุปกรณ์ช่วยฝึกเดินเป็นเรื่องที่ง่ายขึ้น Poonsak Pisek, Somchai Sessirisombat and Bunyong Rungroungdouyboon, "Biomechanical Evaluation of the Maxilla during Maxillary Distraction Osteogenessis with the New Hybrid Distraction Device: A Finite Element Analysis", Journal of the Medical Association of Thailand, V. 100, N. 8, August 2017, p s16-s23. Background: Patients with cleft lip and palate (CLP), who have malocclusion combined with severe skeletal Class III problems, usually have multidimensional maxillary hypoplasia. The present study invented a new hybrid distraction device to correct severe skeletal problems.
Objective: To evaluate biomechanical of a new hybrid distractor device during maxillary sagittal distraction osteogenesis. Material and Method: Three-dimensional finite element skull models of a 20-year-old, non-syndromic male patient with bilateral complete cleft lip and palate was constructed. Stress distributions and displacement of the new hybrid distractor were analyzed using ANSYS v.10.0. Results: The maximum stress levels were observed for both external and internal components of the new hybrid distractor device. The values of maximum stress were not exceeding yield stress and the range of safety factor was 2.36 to 3.76. The maxilla bone was in equilibrium balance between action force and reaction force and showed symmetrical displacement. Conclusion: The new hybrid distractor device has enough strength during maxillary distraction osteogenesis and can provide controlled symmetrical displacement of the maxilla. T. Luckanawat, P. Kooncumchoo and B. Rungroungdouyboon, "Design and Development of the lower limb rehabilitation robot for restoration of normal gait in stroke patients", Journal of Research and Applications in Mechanical Engineering, Transactions of the TSME 2016, Nov 2016 ABSTRACT:
This paper presents new machine of lower limb rehabilitation robot, called “TU Gait Trainer”. The machine has been developed for stroke patients to restore normal gait with trajectory and ankle angle control. While patients were being gotten physical therapy by TU Gait Trainer, their each foot was fastened by foot supporter of the rehabilitation robot and moved follow normal gait pattern by only 1 motor with linkage mechanism which was specific designed for normal gait pattern. During ankles had been moving, TU Gait Trainer was controlling angle of patient’s ankles to move in dorsiflexion and plantarflexion posture same as normal gait pattern also. TU Gait Trainer prototype had been made up and getting efficiency data with real patients. The testing results of real patients with TU Gait Trainer are presented. The results show patients got stronger muscle and they got chance to restore normal walking Phadungsak Rattanadecho, Natt Makul, Aumpol Pichaicherd, Porncharoen Chanamai and Bunyong Rungroungdouyboon, "A novel rapid microwave-thermal process for accelerated curing of concrete: Prototype design, optimal process and experimental investigations", Construction and Building Materials, V.123, 2016, p 768-784 Abstract
In this work, a mobile microwave (MW)-assisted curing unit for the accelerated curing of concrete workpiece is designed based on coupled electromagnetic (MW)–thermal analysis. The design of this unit is described together with experimental investigations into the heating characteristics of concrete workpiece subjected to the MW-accelerated curing process. Mathematical models are applied to design a horn-shaped MW cavity and as a basis for constructing a stationary and a moving MW-accelerated curing unit that uses MW energy at an operating frequency of 2.45 ± 0.05 GHz and at powers of 400W and 800 W. The experiments included the effects of MW curing on the temperature evolution, moisture content variation, and compressive strength development properties of the concrete. Also, the concrete workpiece was compared to water-cured conventional concretes and air-cured conventional concretes on the basis of these properties. Based on the concept of antenna, a rectangular horn-shaped cavity of 246.7 mm wide 333.68 mm long is designed showing a uniform thermal distribution for concrete curing. From the experiments, it was found that the application period for curing using the mobile MW-curing unit was considerably shorter than for conventional curing methods. The appropriate preheating interval is 30 min, and MW energizing for 15 min/time and a paused duration of 60 min produces maximum compressive strength. However, the time needed for curing was considerable. When concrete was heated using MW energy for more than 90 min at over 80 C, the effect was a continuous decrease in compressive strength. Further, at early age, the compressive strength development of the concrete workpiece subjected to MW curing was greater than that achieved by air curing or water wet-curing. Cholaseuk, D., "Optimum Design of Disk Structure under Planar Loads" ,Thammasat International Journal of Sciences and Technology, Vol. 18, No. 4, October-December 2013
Abstract Disk structures under planar loads are commonly found in machines, such as disk brakes, automobile wheels, gears, etc. Weight reduction of such parts reduces inertia of the systems which helps in improving overall performance of the machines. In this research, a numerical method employing a stress-based material distribution scheme is utilized in the design of disk structures. During the process, stress distribution is calculated by finite element method. Then, elements with low stress are successively removed. The iteration process continues until the optimum topology is revealed. It is observed that the optimum topology follows the pattern of the corresponding principal stress trajectories. The resulting designs for different conditions provide a basic guideline for the optimum topology which can serve as a starting point for creating solid models for optimum shape design of disk structures. |
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