• Title/Summary/Keyword: The strength recovery

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INFLUENCE OF SODIUM ALGINATE CONTENTS ON THE STRAIN IN COMPRESSION, ELASTIC RECOVERY, AND COMPRESSIVE STRENGTH OF EXPERIMENTAL ALGINATE IMPRESSION MATERIALS (알긴산소오다 함량이 실험적 알지네이트 인상재의 압축변형율, 탄성회복율 및 압축강도에 미치는 영향)

  • Lee Yong-Sik;Choi Boo-Byung;Lee Sung-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.41 no.2
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    • pp.243-257
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    • 2003
  • The purpose of this study was to search the influences of the increase of the contents of sodium alginate in the experimental alginates on the some mechanical properties. 3 commercial alginates were selected for the purpose of comparison of the results of experiments. 7 experimental alginates were manufactured with the rise of contents of sodium alginate from 8.8% to 18.3% with the decrease of contents of diatomaceous earth and with the constant contents of calcium sulfate 12.5%. sodium phosphate 2.2%, zinc fluoride 2.0%. Splitable metal mold with 12.5mm diameter and 20.0mm height was filled with mixed alginate to prepare the cylinder shaped specimens. Strain in compression, elastic recovery, compressive strength were tested using the ISO specification number 1563, alginate impression material. Experimental groups were 7, and 10 specimens were used for each test items and each groups. Following results were obtained ; 1. Strain in compression was decreased with the increase of sodium alginate contents (p=0.0077, r2 = 0.6302). 2. Elastic recovery was decreased with the increase of sodium alginate contents but was not significant(p=0.0639, r2=0.7449). 3. Compressive strength was increased with the increase of sodium alginate contents (p<0.0001, r2 = 0.9617). These results mean that the increase of sodium alginate contents make alginate harder but may result the increased permanent deformation.

Changes in Antioxidant Enzymes, According to Recovery Methods During Repeated Apnea Diving

  • MOON, Hwang-woon;SONG, Youn-sang;KIM, Jeong-Weon
    • The Korean Journal of Food & Health Convergence
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    • v.7 no.4
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    • pp.23-29
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    • 2021
  • This study analyzes the physiological changes that occur after free diving and studies peroxidants and antioxidants according to the recovery method. Accordingly, the purpose of this study is to provide proper rest methods after free diving and provide basic data for free diving research. Eight male college students recovered for 30 minutes after 20 free injections at a 5-meter diving site, 20 free injections after a week's car wash, and recovered for 30 minutes after collecting blood during recovery to analyze the effects of peroxidants and antioxidants. Comparison of changes in peroxidants and antioxidants in recovery methods after free-diving iterations showed that SOD tended to decrease immediately after free-diving, increasing MDA to 10 minutes after recovery, but no significant difference was found. The purpose of this study is to observe physiological changes according to the recovery method after free diving and to propose an appropriate recovery method after free diving. However, there was no significant difference in all the restoration methods, and 20 freediving was not high kinetic intensity for the subjects, which is believed to have resulted in the following results. Therefore, it was discussed that the repetitive diving strength should be higher to confirm a significant difference in the recovery method after free diving.

Effects of cold water immersion and compression garment use after eccentric exercise on recovery

  • Maruyama, Tatsuhiro;Mizuno, Sahiro;Goto, Kazushige
    • Korean Journal of Exercise Nutrition
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    • v.23 no.1
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    • pp.48-54
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    • 2019
  • [Purpose] The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise. [Methods] Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15℃), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise. [Results] The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant. [Conclusion] CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

Effect of Heat Input and Interpass Temperature on the Strength and Impact Toughness of Multipass Weld Metal in 570MPa Grade Steel (570MPa급 용접구조용강 다층 용접금속의 강도 및 충격인성에 미치는 입열 및 패스간 온도의 영향)

  • Byun, Ji-Chul;Bang, Kook-Soo;Chang, Woong-Sung;Park, Chul-Gyu;Chung, Woo-Hyun
    • Journal of Welding and Joining
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    • v.24 no.1
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    • pp.64-70
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    • 2006
  • 570MPa grade weldable steels were gas metal arc welded with various heat inputs and interpass temperatures using flux cored wires. Effects of heat input and interpass temperature on the strength and impact toughness of weld metal were investigated in terms of microstructural change, recovery of alloying elements, and the amount of reheated weld metal. Increase of heat input and interpass temperature resulted in decrease of weld metal strength. This is because of the small amount of acicular ferrite, large columnar size and low recovery of alloying elements such as manganese and silicon. In addition to the microstructural change, weld metal toughness was also influenced by the deposition sequence. It increased with an increase of the amount of reheated weld metal.

Acupuncture in Sport Recovery: A Brief Review

  • CHAPLEAU, Christopher
    • The Korean Journal of Food & Health Convergence
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    • v.6 no.2
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    • pp.23-26
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    • 2020
  • Active and therapeutic sport recovery is becoming a popular and important component in approving performance for pro and recreational athletes alike. It is also helping in the realm of injury prevention. In the search of finding modalities that are widely effective, natural, and safe, acupuncture is a viable and cost-effective treatment for helping athletes achieve this goal. More direct related research is needed, but testimonials from pro athletes and the body of research that currently exists provides powerful evidence on acupunctures ability to help with enhancing recovery. Specializing in acupuncture and exercise science, Chris integrates acupuncture into musculoskeletal rehabilitation therapy or fitness training for pain modulation, speedy recovery, and enhanced performance. Clients can choose to focus on one-on-one corrective exercise therapy, manual and massage therapy, or acupuncture. However, for best results, Chris recommends all three. Other modalities that he uses in therapy are acu-taping, herbal therapy, nutrition supplementation, cupping, guasha, and stretching techniques. The corrective exercise component is one-on-one body balancing management, focusing on strength and conditioning, post physical rehab - exercise therapy, integrative sport specific exercise, weight loss, core strengthening, dynamic lumbar stabilization, active recovery techniques, and myo-fascial release techniques. The acupuncture component focuses on sport injuries, myofascial pain, peripheral neuropathy, arthritis, facial rejuvenation, stress, smoking cessation, addiction detoxification program, weight management, sport recovery and performance.

Study on the Urethane Restoration Filling Material and Adhesive for Stone Cultural Heritage (석조문화재 복원용 우레탄 메움제 및 접착제에 관한 연구)

  • Han, Won-Sik;Lee, Ho-Youn;Park, Gi-Jung;Hong, Tae-Kee;Wi, Koang-Chul
    • Journal of Conservation Science
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    • v.27 no.1
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    • pp.115-121
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    • 2011
  • A Urethane resin restoration material was made to be used in the restoration of stone cultural assets. The Urethane resin restoration material showed strong adhesive strength and tensile strength similar to epoxy recovery material, which had been mainly used for the recovery of stone cultural assets. The sealing property, anti-shrinking property and paint-ability of Urethane resin restoration material are also similar to existing epoxy system restoration materials. Especially, this Urethane resin restration material is expected to give permanence and continuous stability in the restoration of cultural assets made in stone by resolving the two big issues of existing epoxy recovery material, which are 'yellowing' and 'ir-reversibility'. This Urethane resin restration material had been directly applied as a filling material and adhesive and it was dissolved again. The Urethane resin, which had been used for the recovery, was able to be perfectly removed, which means that this Urethane resin recovery material has perfect reversibility. This Urethane resin restoration material also has enhanced convenience since user can adjust the working-life dependent on work environment. It is believed that this Urethane resin restoration material can also be used as a filling material or adhesive for other cultural assets made of ceramic or metal heritage, in addition to stone, since it has strong adhesive strength and tensile strength.

A study on the increase in shear strength of soil by root systems of indigenous plants (자생초화류 뿌리의 전단강도 보강효과에 대한 연구)

  • Woo, Chull-Woong;Choi, Sang-Woon;Chang, Pyoung-Wuck
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.325-328
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    • 2002
  • Recently, attempts to use indigenous plants have been made for the recovery of nature of slopes and making permanent vegetation group, harmonizing with surroundings from the ecological perspective. For surface failure prevention of slopes, indigenous plants are known as superior to those of exotic grasses, but studies how much indigenous plants influence shear strength of soil is lacking. Therefore, in this study, strength increasement of the root-soil system were investigated for four indigenous plants.

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Non destructive test of Fire-damaged reinforced concreted beams with high strength concrete (화재 피해를 입은 고 강도 철근콘크리트 휨 부재의 비파괴 검사)

  • 신미경;신영수;이차돈;홍성걸;김희선
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.651-654
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    • 2003
  • Non-destructive testing is essential in the inspection of alteration, repair and new construction in construction industry. This paper is to evaluate the strength variation of fire damaged concrete by non-destructive testing. Furthermore, It is to infer the recovery degree of residual strength of fire-damaged concrete. For this purpose, researchers are exploring the performance of non-destructive testing method using ultrasonic testing and Schmidt hammer in concrete specimens. Testing is performed four-times: before fire test, directly after fire test, after 20 days and after 60 days.

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Non destructive test of fire-damaged high strength RC columns with polypropylene fiber (화재피해를 입은 PP섬유 혼입 고강도 콘크리트부재의 비파괴 검사)

  • Jung, Hye-Won;Choi, Eun-Gyu;Shin, Yeong-Soo;Lee, Cha-Don;Kwon, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.65-68
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    • 2006
  • This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column with polypropylene by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns, Schmidt hammer test is used. Testing is performed four-times: before fire test, directly after fire test, after 30 days and after 4 months.

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