• Title/Summary/Keyword: Strength Control

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Strength Properties of Wooden Model Erosion Control Dams Using Domestic Pinus rigida Miller I (국내산 리기다소나무를 이용한 목재 모형 사방댐의 강도 성능 평가 I)

  • Kim, Sang-Woo;Park, Jun-Chul;Lee, Dong-Heub;Son, Dong-Won;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.6
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    • pp.77-87
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    • 2008
  • Wooden model erosion control dam was made with pitch pine, of which the strength properties was evaluated. Wooden model erosion control dam was made with diameter 90 mm of pitch pine round posts treated with CUAZ-2 (Copper Azole), changing joint in three different types. In each type, erosion control dam was made in nine floor (cross-bar of five floors and vertical-bar of four floors), of which the hight was 790 mm. And then strength properties were investigated through horizontal loading test and impact strength test, and the deformation of structure through image processing (AICON 3D DPA-PRO system). In horizontal loading test of wooden model erosion control dam using round post of diameter 90 mm, whether there was stone or not did not affect strength much when using self drill screw, but strength was decreased by 23%. In monolithic type of erosion control dam using screw bar, strength was increased by 1.5 times and deformation was decreased when filling with stone. When reinforcing with screw bar that ring is connected to self drill screw, strength was increased by 4.8 times. In impact strength test of wooden model erosion control dam made with round post of diameter 90 mm, the erosion control dam connected with self drilling screw not filling with stone was totally destroyed by the 1st impact, and the erosion control dam using screw bar was ruptured at cross-bar at which 779 kgf of impact was loaded in the 1st impact. In the 2nd impact, the base parts were ruptured, and reaction force was decreased to 545 kgf. In the 3rd impact, whole base parts were destroyed, and reaction force was decreased to 263 kgf.

Effect of different grinding burs on the physical properties of zirconia

  • Lee, Kyung-Rok;Choe, Han-Cheol;Heo, Yu-Ri;Lee, Jang-Jae;Son, Mee-Kyoung
    • The Journal of Advanced Prosthodontics
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    • v.8 no.2
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    • pp.137-143
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    • 2016
  • PURPOSE. Grinding with less stress on 3Y-TZP through proper selection of methods and instruments can lead to a long-term success of prosthesis. The purpose of this study was to compare the phase transformation and physical properties after zirconia surface grinding with 3 different grinding burs. MATERIALS AND METHODS. Forty disc-shaped zirconia specimens were fabricated. Each Ten specimens were ground with AllCeramic SuperMax (NTI, Kahla, Germany), Dura-Green DIA (Shofu Inc., Kyoto, Japan), and Dura-Green (Shofu Inc., Kyoto, Japan). Ten specimens were not ground and used as a control group. After the specimen grinding, XRD analysis, surface roughness test, FE-SEM imaging, and biaxial flexural strength test were performed. RESULTS. After surface grinding, small amount of monoclinic phase in all experimental groups was observed. The phase change was higher in specimens, which were ground with Dura-Green DIA and AllCeramic SuperMax burs. The roughness of surfaces increased in specimens, which were ground with Dura-Green DIA and AllCeramic SuperMax burs than control groups and ground with Dura-Green. All experimental groups showed lower flexural strength than control group, but there was no statistically significant difference between control group and ground with Dura-Green DIA and AllCeramic SuperMax burs. The specimens, which were ground with Dura-Green showed the lowest strength. CONCLUSION. The use of dedicated zirconia-specific grinding burs such as Dura-Green DIA and AllCeramic SuperMax burs decreases the grinding time and did not significantly affect the flexural strength of zirconia, and therefore, they may be recommended. However, a fine polishing process should be accompanied to reduce the surface roughness after grinding.

Effects of the Abdominal Drawing-in Maneuver and the Abdominal Expansion Maneuver on Grip Strength, Balance and Pulmonary Function in Stroke Patients

  • Yoon, Mi-Ra;Choi, Ho-Suk;Shin, Won-Seob
    • The Journal of Korean Physical Therapy
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    • v.27 no.3
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    • pp.147-153
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    • 2015
  • Purpose: The purpose was to determine whether the application of the abdominal drawing-in maneuver (ADIM) and abdominal expansion maneuver (AEM) to stroke patients would affects their trunk stability, balance, pulmonary function, and grip strength. Methods: The subjects were 36 stroke patients who were randomly and equally assigned to an ADIM group (n=12), an AEM group (n=12), and a control group (n=12). The intervention was applied to each group three times per week, 30 minutes each time, for four weeks. Outcome measures were grip strength, modified functional reach test (mFRT) and pulmonary function. Pulmonary function were measured force expiratory volume at one second (FEV1), forced vital capacity (FVC), FEV1/FVC and peak expiratory flow (PEF) values. Results: The results of the three groups showed statistically significant improvements in grip strength. The AEM group showed significantly greater differences in grip strength than either the ADIM group or the control group. In the anterior mFRT, the ADIM group showed significantly improvements than the control group. The ADIM and AEM groups were showed statistically significant greater improvements in PEF between the baseline and post-intervention and the post-analysis revealed that the AEM group showed significantly greater improvements than the control group. Conclusion: The results of this study indicate that the ADIM and AEM were effective in improving the PEF of pulmonary function. The ADIM was more effective than AEM in trunk stabilization.

The Effects of Proprioceptive Neuromuscular Facilitation Lower Extremity Pattern on Muscular Strength and Flexibility in an Aquatic Environment (수중에서 고유수용성신경근촉진법 하지 패턴이 근력 및 유연성에 미치는 영향)

  • Lee, Dong-Kyu;Kim, Yong-Nam
    • The Journal of Korean Physical Therapy
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    • v.25 no.2
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    • pp.49-55
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    • 2013
  • Purpose: This study was conducted in order to analyze the effect of proprioceptive neuromuscular facilitation lower extremity pattern on muscular strength and flexibility in an aquatic environment. Methods: Ten members of the experimental group and 10 members of the control group were randomly selected from 20 college students who are in their 20s. Bilateral symmetry pattern among proprioceptive neuromuscular facilitation lower extremity patterns was applied in an aquatic environment in the experimental group three times per week for a period of six weeks, and a set consisted of 10 times, which was repeated 10 times. On the other hand, subjects in the control group did not receive any treatment while maintaining daily life. Muscular strength was measured using a dynamometer and electromyogram system for maximum voluntary isometric contraction of hip flexor, hip extensor, knee flexor, and knee extensor. Cervical flexibility was measured using cervical range of motion instrument for cervical flexion, rotation, and lateral flexion. Lumbar flexibility was measured using back range of motion instrument II for lumbar flexion. Results: For the experimental group, significance was observed for hip flexor, extensor, knee flexor, extensor, cervical flexion, rotation, lateral flexion, and lumbar flexion. For the control group, no significance was observed for any other variables except for cervical flexion. As a result of observation of difference between the two groups, relatively high significance was observed in the experimental group, compared with the control group. Conclusion: In conclusion, proprioceptive neuromuscular facilitation lower extremity pattern had a positive effect on muscular strength and flexibility in an aquatic environment.

The effects of motion taping on young males' lumbar stabilization exercise

  • Cho, Yong-ho;Choi, Jin-ho
    • Journal of the Korean Society of Physical Medicine
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    • v.10 no.3
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    • pp.67-72
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    • 2015
  • PURPOSE: This study was conducted to examine the effects of motion taping on the effects of lumbar stabilization exercise. METHODS: The subjects of this study were 24 normal males with no problem in their nervous systems or musculoskeletal systems. The subjects were randomly assigned to a control group of 12 subjects and an experimental group of 12 subjects. The control group was applied with lumbar stabilization exercise while the experimental group was applied with lumbar stabilization exercise after being attached with tapes. The intervention period was four weeks in total and the subject underwent the exercises three times per week. The exercise time per session was set to one hour in principle consisting of warm-up exercise and cool-down exercise for 10 minutes each and main exercise for 40 minutes. Lumbar muscle strength was measured as a factor to examine the effects of lumbar stabilization exercises. RESULTS: The control group showed an increase in lumbar muscle strength from $111{\pm}6.30kg$ to $113{\pm}6.23kg$ and the experimental group showed an increase in lumbar muscle strength from $108{\pm}6.46kg$ to $116{\pm}5.21kg$. The increases shown by both groups were statistically significant and the experimental group that was applied with motion taping showed a larger increase in lumbar muscle strength compared to the control group. CONCLUSION: Lumbar stabilization exercise is considered to be good for lumbar stability and muscle strengthening and lumbar stabilization exercise applied with motion taping is considered to show larger effects for muscle strengthening and the improvement of lumbar functions.

Neuromuscular electrical stimulation improves strength, pain and weight distribution on patients with knee instability post surgery

  • Asakawa, Yasuyoshi;Jung, Ji-Hye;Koh, Si-Eun
    • Physical Therapy Rehabilitation Science
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    • v.3 no.2
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    • pp.112-118
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    • 2014
  • Objective: The purpose of this study was to investigate the effects of an exercise with and without neuromuscular electrical stimulation (NMES) of the quadriceps femoris muscle, on strength, pain, and weight distribution in patients with knee instability post surgery. Design: Randomized controlled trial. Methods: Twenty patients in the early stage of rehabilitation after knee surgery were recruited as subjects and were randomly divided into either experimental group (exercise combined with NMES) (n=10) or control group (n=10). Both groups received strength training of the lower limb for 20 min/day, 5 days/week for 4 weeks. The experimental group used NMES for unilateral quadriceps femoris training with incremental increases in the intensity of isometric contraction over 4 weeks. Outcome measurements were assessed using the digital manual muscle testing, 30-chair stand test (30CST), numeric pain rating scale (NPRS) and weight distribution using the foot analyzer before and after 4 weeks of training. Results: After the 4-week intervention, knee extensor strength increased significantly in the experimental group post intervention (p<0.05), and there was a significant improvement in the experimental group compared with the control group (p<0.05). The 30CST and NPRS scores improved significantly in the experimental group compared to the control group (p<0.05), and there was a significant difference between the two groups (p<0.05). Weight distribution was significantly improved in the experimental group compared with the control group, (p<0.05), but there was no significant difference in improvement between the two groups. Conclusions: This study showed that NMES combined with strengthening exercises of the lower limbs is effective in improving lower limb pain and strength in patients with instability after knee surgery.

Potential of Erythrosine-Mediated Photodynamic Therapy as a Cavity Disinfectant: Antibacterial Efficacy and Bonding Ability

  • Gawon Lee;Haeni Kim;Siyoung Lee;Juhyun Lee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.51 no.3
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    • pp.290-298
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    • 2024
  • This study aimed to evaluate the antibacterial efficacy of erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) in dentin and its effect on the shear bond strength (SBS) of composite resin to dentin. Eighty extracted human noncarious premolars were used in this study. Forty teeth were used for the antibacterial activity test, while the remaining 40 were used for the SBS test. Both experiments were conducted with 4 experimental groups (n = 10): control (distilled water), sodium hypochlorite (NaOCl, 6%), chlorhexidine (CHX, 0.12%), and erythrosine-mediated PDT. Antibacterial effects were evaluated by counting S. mutans colony-forming units (CFUs). The SBS of composite resins to dentin was measured using a universal testing machine. All treatments (NaOCl, CHX, and PDT) demonstrated statistically significant differences in antibacterial activity compared with the control group (p < 0.05). The antibacterial effects were ranked from strongest to weakest as follows: NaOCl, PDT, and CHX. In the SBS test, the NaOCl group exhibited a statistically significant difference compared with the CHX, PDT, and control groups (p < 0.05), with the lowest bond strength. No statistically significant differences were found among the CHX, PDT, and control groups (p > 0.05). Erythrosine-mediated PDT exhibited significant antibacterial effects against S. mutans, with higher antibacterial activity than CHX but lower than NaOCl. Only NaOCl negatively affected the bond strength of composite resin to dentin. In conclusion, erythrosine-mediated PDT shows potential as a cavity disinfectant due to its significant antibacterial effects against S. mutans and lack of adverse effects on bond strength.

An Evaluation of Mechanical Properties of Ultra High Strength Concrete(UHSC) (초고강도 콘크리트의 재료역학적 특성 평가)

  • Lim Hee Jae;Shin Sung Woo;Ahn Jong Mun;Lee Kwang Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.281-284
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    • 2004
  • The most important reason of using of ultra high strength concrete in super tall building is that ultra high strength concrete can reduce the section of members and control side sway effectively. However, the practical utilization of ultra high strength concrete is dependent not only on the production techniques, but also the overall preparation including proper code provisions, construction technique. The purpose of this study is to evaluate of mechanical properties of UHSC, such as modulus of elasticity, stress-strain behavior, modulus of rupture and tensile splitting strength. It is similar to normal or high strength concrete but necessary to discern the difference between normal or high strength concrete and ultra high strength concrete and modify existed equations. And in this study another important factor is to discern the difference according to member size, curing method in ultra high strength concrete experimentally.

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The Effect of Shoulder Exercise Program for Improving Forward Head Posture (전방머리자세 개선을 위한 어깨근육 운동프로그램의 효과)

  • Lee, Geoncheol;Bae, Wonsik
    • Journal of The Korean Society of Integrative Medicine
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    • v.3 no.3
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    • pp.1-8
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    • 2015
  • Purpose : The purpose of this study was to find out the effect of shoulder exercise program for improving forward head posture. Method : Subjects were divided into two groups. The experimental group(15 people) participated in strength exercise and stretching exercise, three times every week, during 4 weeks. And the control group(the other 15 people) didn't participate in exercises. Exercise program was composed of strength exercise of middle and lower trapezius and stretching exercise of levator scapulae and upper trapezius. And then we measured cervical alignment with GPS and muscular activity by EMG. Result : The results of this study were as follows; 1. After the intervention, experimental group was significantly decreased in cervical alignment than control group(p<.05). 2. After the intervention, experimental group was significantly increased in middle lower trapezius musclar activity than control group(p<.05). Conclusion : Strength exercise of middle and lower trapezius and stretching exercise of levator scapulae and upper trapezius were considered a efficient for improving forward head posture.

The Effects of an Elderly Health Promotion Program on Health Promotion Lifestyles, Health Status and Quality of Life in the Elderly (노인 건강증진대학 프로그램이 노인의 건강증진행위, 건강상태 및 삶의 질에 미치는 효과)

  • Park Jeong Sook
    • Journal of Korean Academy of Nursing
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    • v.34 no.7
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    • pp.1194-1204
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    • 2004
  • Purpose: The purpose of this research was to identify the effect of an elderly health promotion program on health promotion lifestyles, health status, and quality of life in the elderly. Method: The research design was a nonequivalent control group pre post experimental design. Thirty two elderly persons were in the experimental group and the other thirty two elderly were in the control group. A 16 week health promotion program was given to the experimental group. The measurement tools were HPLP II, grip strength, back lift strength, flexibility, body fat percentile, blood sugar, serum cholesterol, and quality of life. Result: The experimental group showed a higer score of health promoting lifestyles, flexibility, grip strength, back lift strength, and quality of life. There were no differences in body fat percentiles, blood sugar and serum cholesterol between the experimental and control group. Conclusion: This health promotion program for elderly can be recommended as an effective nursing intervention for elderly in a community.