• 제목/요약/키워드: International joint research

검색결과 426건 처리시간 0.025초

Microstructure and Tensile Properties of SS400 Carbon Steel and SUS430 Stainless Steel Butt Joint by Gas Metal Arc Welding

  • Poonnayom, Pramote;Chantasri, Sakchai;Kaewwichit, Jesada;Roybang, Waraporn;Kimapong, Kittipong
    • International Journal of Advanced Culture Technology
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    • 제3권1호
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    • pp.61-67
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    • 2015
  • The application of SS400 carbon steel and AISI430 ferritic stainless steel joint has been increased in industries because of the advantage of both metals was able to increase the service lifetime of the important structures. Therefore, a fusion welding process that could produce a sound weld and good joint properties should be optimized. This research is aimed to weld a butt joint of SS400 carbon steel and AISI430 ferritic stainless steel using Gas Metal Arc Welding (GMAW) welding process and to study the effects of welding parameters on joint properties. The experimental results were concluded as follows. The optimized welding parameter that produced the tensile strength of 448 MPa was the welding current of 110A, the welding speed of 400 mm/min and the mixed gas of $80%Ar+20%CO_2$. Increase of the welding current affected to increase and decrease the tensile strength of the joint, respectively. Lower welding current produced the incomplete bonding of the metals and indicated the low tensile strength. Microstructure investigation of the welded joint showed a columnar grain in the weld metal and a coarse grain in the heat affected zone (HAZ). The unknown hard precipitated phases were also found at the grain boundaries of the weld metal and HAZ. The hardness profile did not show the difference of the hardness on the joint that was welded by various welding currents but the hardness of the weld metal was higher than that of the other location.

The Effects of Vibration Exercise after Modified Bröstrom Operation in Soccer Players with Ankle Instability

  • Kim, Sanghoon;Kim, Yangrae;Kim, Yongyoun
    • 국제물리치료학회지
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    • 제10권2호
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    • pp.1791-1796
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    • 2019
  • Background: Vibration exercise after ankle surgery improves proprioception and ankle muscle strength through vibration stimulation. Objective: To examine the effects of vibration exercise on the ankle stability. Design: Randomized controlled clinical trial (single blind) Methods: Twenty soccer players were randomly divided into experimental group and control group. The Vibration exercise program was conducted 12 weeks and 3 times a week. Ankle joint proprioceptive sensory test and Isokinetic muscle strength test were performed using Biodex system pro III to measure plantar flexion / dorsiflexion and eversion / inversion motion. Results: The result of isokinetic test of ankle joint is showed significant improvement in all measurement items, such as leg flexion, lateral flexion, external and internal muscle forces, compared to previous ones by performing vibration movements for 12 weeks. However, in the comparison group, plantar flexor ($30^{\circ}$), eversion muscle ($120^{\circ}$), inversion ($30^{\circ}$) of limb muscle strength were significantly improved compared with the previous phase; was no significant difference in dorsi-flexion. There was no significant difference between groups in all the items. Conclusions: In this study, we analyzed the effects of rehabilitation exercise on soccer players who had reconstructed with an ankle joint ligament injury through vibration exercise device. As a result, we could propose an effective exercise method to improve the ability, and confirmed the applicability as an appropriate exercise program to prevent ankle injuries and help quick return.

A Comparative Evaluation of Closed and Open Kinetic Exercises in the Management of Chronic Ankle Instability

  • Jung, Namjin
    • 국제물리치료학회지
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    • 제11권4호
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    • pp.2212-2220
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    • 2020
  • Background: Repetitive damage to the ankle joint causes chronic ankle instability, and studies comparing the effects of exercise in open and closed chains as a treatment method are very rare. Objectives: To investigate the effects of open and closed kinetic exercises on muscle activity and dynamic balance of ankle joint in adults with chronic ankle instability. Design: Single-blind randomized controlled trial. Methods: The selected 30 subjects are randomly divided into open kinetic chain exercise experimental group (EGI, n=10), closed kinetic chain exercise experimental group (EGII, n=10), and stretching control group (CG, n=10). Open and closed kinetic exercises lasted 30 minutes three times a week for six weeks and stretching exercises performed four actions for 20 seconds and five sets. The measurement tools using surface electromyography to measure muscle activity in the ankle joint. The dynamic balance of the ankle was evaluated using the Y-Balance test. Results: Following the intervention, closed and open kinetic chain exercise group showed significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance (P<.05). However, no significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance between closed and open kinetic chain exercise group (P<.05). Conclusion: This study provides evidence that closed and open kinetic chain exercise can be presented as an effective exercise for the muscle activity of ankle muscle and dynamic balance of the subject with chronic ankle instability.

The Effects of GMAW Parameters on Penetration, Hardness and Microstructure of AS3678-A350 High Strength Steel

  • Kaewsakul, Nut;Putrontaraj, Rungsuk;Kimapong, Kittipong
    • International Journal of Advanced Culture Technology
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    • 제3권1호
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    • pp.169-178
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    • 2015
  • This research aims to study the effects of various welding parameters in gas metal arc welding (GMAW) process on welding penetration, microstructure and hardness of AS3578-A350 high strength steel with the thickness of 10 mm. The welding process parameters were a welding current of 100-200A, an arc voltage of 20-30V, a welding speed of 20-60 cm/min and a gas shielding type of Ar and $Ar+CO_2$. The summarized experimental results are as follows. An increase of the welding current and voltage affected to increase the penetration depth of the joint. However, when the welding speed was decreased, it increased the penetration depth of the joint. Using the Ar gas for shielding the weld area, produced the higher penetration depth and the less narrow weld bead than the joint that was shielded by the mix gas of $Ar+CO_2$. The variation of the welding process parameters affected to produce the various microstructures of weld metal and heat affected zone and also showed the various kind of hardness along the weld joint.

Rationales and Evidence of Elastic Taping: A clinician's perspective

  • Langendoen, John;Fleishman, Caren;Kim, Soon Hee;An, Ho Jung
    • 국제물리치료학회지
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    • 제7권1호
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    • pp.979-988
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    • 2016
  • The purpose of this systematic review is to investigate the effects of tape application on improving body conditions. The search strategy for this review included a literature search by members of the International Kinematic Academy in 12 countries between January 2014 and February 2015 using PubMed, CINAHL, Cochrane, Google Scholar, websites and national journals. The search words included "Kinesiotape, Kinesio tape, kinesiotaping, elastic taping, taping, functional taping, myofascial taping, sensomotor taping". The review included all articles, even those published in different languages. These searches resulted in 821 publications. There are several effects of tape application were revealed such as improving blood circulation, lymphatic circulation, body range of motion, activation of mechanoreceptor and joint stability, and decreasing pain. No one negative about the positive effects of taping, however the more effort is required to find evidence of effects of tape application.

Effect of Ankle Joint Mobilization and FES on Change of Ankle Movement and the Quality of Gait in Patients with Hemiplegia

  • Lee, Hyun Suk;Park, Si Eun;Lee, Sang Bin;Kim, Bo Kyoung;Shin, Hee Joon;Kim, Hong Rae;Choi, Young Duk;Min, Kyung Ok
    • 국제물리치료학회지
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    • 제5권2호
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    • pp.738-742
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    • 2014
  • This study was conducted to investigate the effect of FES and ankle mobilization on the ankle motion and the quality of gait of chronic hemiplegic patients with limited ankle joint motions. As research subjects, 24 chronic hemiplegic patients who could walk independently, regardless of assistive aids, were selected. Then, 8 subjects received mobilization randomly and 8 subjects received FES and 8 subjects received mobilization and FES, at the same time. The dorsiflexion PROM significantly increased in the group of mobilization therapy, mobilization and FES all together(p<.01). There were statistically significant differences among the three groups(p<.01). The 10m walking test significantly decreased in the group of mobilization therapy, mobilization and FES all together(p<.05). There were statistically significant differences among the three groups(p<.01). The gait velocity significantly increased in the group of mobilization therapy, FES therapy, mobilization and FES all together(p<.05). There were statistically significant differences among the three groups(p<.01). The stride length significantly increased in the group of mobilization therapy, mobilization and FES all together(p<.05). There were statistically significant differences among the three groups(p<.05). In conclusion, these findings demonstrate that rather than only using one treatment technique, applying mobilization and FES together brings a more satisfactory result to hemiplegic patients with limited ankle joint motions.

Impact of cable sag on the efficiency of an inertial mass damper in controlling stay cable vibrations

  • Wang, Zhi-hao;Gao, Hui;Xu, Yan-wei;Chen, Zheng-qing;Wang, Hao
    • Smart Structures and Systems
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    • 제24권1호
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    • pp.83-94
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    • 2019
  • Passive negative stiffness dampers (NSDs) that possess superior energy dissipation abilities, have been proved to be more efficient than commonly adopted passive viscous dampers in controlling stay cable vibrations. Recently, inertial mass dampers (IMDs) have attracted extensive attentions since their properties are similar to NSDs. It has been theoretically predicted that superior supplemental damping can be generated for a taut cable with an IMD. This paper aims to theoretically investigate the impact of the cable sag on the efficiency of an IMD in controlling stay cable vibrations, and experimentally validate superior vibration mitigation performance of the IMD. Both the numerical and asymptotic solutions were obtained for an inclined sag cable with an IMD installed close to the cable end. Based on the asymptotic solution, the cable attainable maximum modal damping ratio and the corresponding optimal damping coefficient of the IMD were derived for a given inertial mass. An electromagnetic IMD (EIMD) with adjustable inertial mass was developed to investigate the effects of inertial mass and cable sag on the vibration mitigation performance of two model cables with different sags through series of first modal free vibration tests. The results show that the sag generally reduces the attainable first modal damping ratio of the cable with a passive viscous damper, while tends to increase the cable maximum attainable modal damping ratio provided by the IMD. The cable sag also decreases the optimum damping coefficient of the IMD when the inertial mass is less than its optimal value. The theoretically predicted first modal damping ratio of the cable with an IMD, taking into account the sag generally, agrees well with that identified from experimental results, while it will be significantly overestimated with a taut-cable model, especially for the cable with large sag.

Kinetics Analysis during Stance Phase of Fore Foot Contact versus Rear Foot Contact in Running

  • Cho, Woong;Han, Jae Woong;Kim, A Young;Park, Sung Kyu;Kim, Hyung Soo
    • 국제물리치료학회지
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    • 제8권1호
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    • pp.1084-1089
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    • 2017
  • The purpose of this study was to compare and analyze the difference of the ankle joint movements during landing. Seven adult males voluntarily participated in the study and the average foot size of the subjects was 269.8 mm. Image analysis equipment and the ground reaction force plate (landing type) was used to measure th kinetic variables. As a result of this study, it was confirmed that the vertical ground reaction force peak point appeared once in the barefoot with forefoot, while two peak points appeared in the barefoot and functional shoe foot with rear foot landing. About ankle angle, fore foot landing ankle angle, the average with bare foot landing was $-10.302^{\circ}$ and the average with functional shoe foot landing was $-2.919^{\circ}$. Also about rear foot landing, ankle angle was $11.648^{\circ}$ with bare foot landing and $15.994^{\circ}$ with functional shoe landing. The fore foot landing, ankle joint force analysis produced 1423.966N with barefoot and 1493.264N with functional shoes. But, the rear foot landing, ankle joint force analysis produced 1680.154N with barefoot and 1657.286N with functional shoes. This study suggest that the angle of ankle depends on the landing type and bare foot running/functionalized shod running, and ankle joint forces also depends on landing type.

The Effects of Maitland Thoracic Mobilization Method on Cervical Alignment and Muscle Activity in Adult with Forward Head Posture

  • Kim, Dajeong;An, Hojung;Kim, Nyeonjun;Kim, Ayeon;Hong, Geurin;Kim, Soonhee
    • 국제물리치료학회지
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    • 제11권3호
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    • pp.2119-2125
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    • 2020
  • Background: Adults with forward head posture (FHP) often suffer from thoracic hyperkyphosis and thoracic dysfunction, and including reduction of the craniovertebral angle (CV angle) and tightening of the superficial neck muscles. In order to treat thoracic dysfunction, interventions aimed at improving thoracic mobility are necessary. Objectives: To examine the effects of maitland manual mobilization therapy on the thoracic spine in adults with FHP. Design: Single-blind randomized controlled trial. Methods: Thirty adults with FHP who met the selection criteria were randomized to the thoracic multiple joint mobilization (TMJM; n=15) group and the thoracic general joint mobilization (TGJM; n=15) group. Joint mobilizations were performed for 23 minutes a day for 4 weeks continuously, two times per week. Outcome measures were ImageJ, BTS FREE EMG 1000, neck disability Index (NDI). Results: Although changes in the left sternocleidomastoid muscle activity and NDI scores over time between the two groups differed, other variables were noted only changes observed over time. Muscle activity in the right sternocleidomastoid increased again in the TGJM group post-intervention and 2 weeks after the end of the experiment, but changes in other variables were retained or improved, confirming the lasting effects of thoracic joint mobilization. Conclusion: Thoracic multiple joint mobilization may be recommended as a more effective intervention for adults with FHP.

Dietary corn resistant starch regulates intestinal morphology and barrier functions by activating the Notch signaling pathway of broilers

  • Zhang, Yingying;Liu, Yingsen;Li, Jiaolong;Xing, Tong;Jiang, Yun;Zhang, Lin;Gao, Feng
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권12호
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    • pp.2008-2020
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    • 2020
  • Objective: This study was conducted to investigate the effects of dietary corn resistant starch (RS) on the intestinal morphology and barrier functions of broilers. Methods: A total of 320 one-day-old broilers were randomly allocated to 5 dietary treatments: one normal corn-soybean (NC) diet, one corn-soybean-based diet supplementation with 20% corn starch (CS), and 3 corn-soybean-based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS) (identified as 4% RS, 8% RS, and 12% RS, respectively). Each group had eight replicates with eight broilers per replicate. After 21 days feeding, one bird with a body weight (BW) close to the average BW of their replicate was selected and slaughtered. The samples of duodenum, jejunum, ileum, caecum digesta, and blood were collected. Results: Birds fed 4% RS, 8% RS and 12% RS diets showed lower feed intake, BW gain, jejunal villus height (VH), duodenal crypt depth (CD), jejunal VH/CD ratio, duodenal goblet cell density as well as mucin1 mRNA expressions compared to the NC group, but showed higher concentrations of cecal acetic acid and butyric acid, percentage of jejunal proliferating cell nuclear antigen-positive cells and delta like canonical Notch ligand 4 (Dll4), and hes family bHLH transcription factor 1 mRNA expressions. However, there were no differences on the plasma diamine oxidase activity and D-lactic acid concentration among all groups. Conclusion: These findings suggested that RS could suppress intestinal morphology and barrier functions by activating Notch pathway and inhibiting the development of goblet cells, resulting in decreased mucins and tight junction mRNA expression.