• 제목/요약/키워드: Average stiffness

검색결과 224건 처리시간 0.026초

무릎 골관절염의 도침 치료에 대한 연구 동향 : 체계적 문헌 고찰 (Research Trends on the Acupotomy Treatment for Knee Osteoarthritis : A Systematic Review)

  • 홍수민;윤광식
    • 동의생리병리학회지
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    • 제34권6호
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    • pp.285-298
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    • 2020
  • This study aimed to review clinical studies about Acupotomy used for Knee Osteoarthritis. We searched the following 12 online databases (KISS, NDSL, RISS, OASIS, Earticle, Kmbase, MEDLINE/Pubmed, Cochrane library, Ebscohost, Ovid, CNKI, Wanfang), to find randomized controlled trials that used Acupotomy for knee osteoarthritis. The methodological quality of randomized controlled trials were assessed by using the Cochrane risk of bias tool and meta-analyses were performed. 16 randomized controlled trials were included. Total number of patients was 1169. The average duration of treatment was 3.14 weeks and most of the patients were treated once a week. The major treatment sites were ligaments, muscles, and tender nodules and the most used evaluation tool was the efficiency. We selected 4 studies and meta-analyzed them. All of the studies performed Acupotomy+sodium hyaluronate injection as a treatment group, and sodium hyaluronate injection as a control group. Meta-analysis showed positive results for Acupotomy+sodium hyaluronate injection in terms of efficiency rate compared to sodium hyaluronate injection. Also Meta-analysis showed positive results for Acupotomy+sodium hyaluronate injection in terms of WOMAC (pain, stiffness, function) compared to sodium hyaluronate injection. In this study, we reviewed studies about Acupotomy used for knee osteoarthritis. The studies showed that Acupotomy can significantly effective on knee osteoarthritis. But according to Cochrane Risk of Bias (RoB) evaluation method, most of the study's risk of bias was unclear. Threrefore, more high-quality studies will be needed.

Effects of new construction technology on performance of ultralong steel sheet pile cofferdams under tidal action

  • Li, Ping;Sun, Xinfei;Chen, Junjun;Shi, Jiangwei
    • Geomechanics and Engineering
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    • 제27권6호
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    • pp.561-571
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    • 2021
  • Cofferdams made of teel sheet piles are commonly utilized as support structures for excavation of sea-crossing bridge foundations. As cofferdams are often subject to tide variation, it is imperative to consider potential effects of tide on stability and serviceability of sheet piles, particularly, ultralong steel sheet piles (USSPs). In this study, a real USSP cofferdam constructed using new construction technology in Nanxi River was reported. The design of key parts of USSP cofferdam in the presence of tidal action was first introduced followed by the description of entire construction technology and associated monitoring results. Subsequently, a three-dimensional finite-element model corresponding to all construction steps was established to back-analyze measured deflection of USSPs. Finally, a series of parametric studies was carried out to investigate effects of tide level, soil parameters, support stiffness and construction sequence on lateral deflection of USSPs. Monitoring results indicate that the maximum deflection during construction occurred near the riverbed. In addition, measured stress of USSPs showed that stability of USSP cofferdam strengthened as construction stages proceeded. Moreover, the numerical back-analysis demonstrated that the USSP cofferdam fulfilled the safety requirements for construction under tidal action. The maximum deflection of USSPs subject to high tide was only 13.57 mm at a depth of -4 m. Sensitivity analyses results showed that the design of USSP cofferdam system must be further improved for construction in cohesionless soils. Furthermore, the 5th strut level before concreting played an indispensable role in controlling lateral deflection of USSPs. It was also observed that pumping out water before concreting base slab could greatly simplify and benefit construction program. On the other hand, the simplification in construction procedures could induce seepage inside the cofferdam, which additionally increased the deflection of USSPs by 10 mm on average.

Measurement and Analysis of Physical Environmental Load during Handling and Distribution of Domestic Fruits -Focused on Seongju Korean Melon

  • Jongmin Park;Donghyun Kim;Wontae Seo;Hyunmo Jung
    • 한국포장학회지
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    • 제29권2호
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    • pp.129-138
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    • 2023
  • The proportion of agricultural products handled through the Agricultural Products Processing Center (APC) is also steadily increasing every year, and in the case of Seongju Korean melon, a total of 10 APCs of Nonghyup and farming association corporations are in operation, and the distribution ratio is about 60% based on total production. In this study, Seongju Korean melon was selected as a target to analyze the environment load during carrying (production farm ~ APC) in the production area and the transport environment load during distribution of domestic fruits, and to analyze the environmental load for handling at APC. The vertical average vibration intensity (overall Grms of 1~250 Hz) of truck transport measured at three transport routes from Seongju Korean melon producer ~ APC, Seongju ~ Seoul and Seongju ~ Jeju was about three times larger than that in the lateral direction and 4.5 times larger than that in the longitudinal direction, respectively. The frequency of occurrence of high-amplitude events (G) in the vertical direction compared to the measuring time was deeply related to pavement conditions in the order of unpaved farm-roads, concretepaved farm-roads, and asphalt-paved main-roads, but overall Grms for the entire frequency band is believed to have a greater impact on vehicle traveling speed than road conditions. On the other hand, the difference in the size and direction of the vibration intensity measured by the forklift truck's main-body and the attachment (fork carrier) during handling at Seongju Korean melon APC was clear, and the vibration intensity of the forklift truck's main-body was largely affected by the stiffness of the fork and the mast according to the handling weight. Based on the field-data of the transport environment during domestic distribution measured through this study, it is believed that it is possible to develop a lab-based simulation protocol for appropriate packaging design.

Effect of variation of water retention characteristics due to leachate circulation in municipal solid waste on landfill stability

  • M. Sina Mousavi;Yuan Feng;Jongwan Eun;Boo Hyun Nam
    • Geomechanics and Engineering
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    • 제33권2호
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    • pp.141-154
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    • 2023
  • This study investigated the effect of water retention characteristics between aged and fresh Municipal Solid Waste (MSW) on the stability of the landfill. A series of transient numerical modeling for the slope of an MSW landfill was performed considering the variation of water retention characteristics due to leachate circulation. Four different scenarios were considered in this analysis depending on how to obtain hydraulic conductivity and the aging degree of materials. Unsaturated hydraulic properties of the MSW used for the modeling were evaluated through modified hanging column tests. Different water retention properties and various landfill conditions, such as subgrade stiffness, leachate injection frequency, and gas and leachate collection system, were considered to investigate the pore water distribution and slope stability. The stability analyses related to the factor of safety showed that unsaturated properties under those varied conditions significantly impacted the slope stability, where the factor of safety decreased, ranging between 9.4 and 22%. The aged materials resulted in a higher factor of safety than fresh materials; however, after 1000 days, the factor of safety decreased by around 10.6% due to pore pressure buildup. The analysis results indicated that using fresh materials yielded higher factor of safety values. The landfill subgrade was found to have a significant impact on the factor of safety, which resulted in an average of 34% lower factor of safety in soft subgrades. The results also revealed that a failed leachate collection system (e.g., clogging) could result in landfill failure (factor of safety < 1) after around 298 days, while the leachate recirculation frequency has no critical impact on stability. In addition, the accumulation of gas pressure within the waste body resulted in factor of safety reductions as high as 24%. It is essential to consider factors related to the unsaturated hydraulic properties in designing a landfill to prevent landfill instability.

Whole-life wind-induced deflection of insulating glass units

  • Zhiyuan Wang;Junjin Liu;Jianhui Li;Suwen Chen
    • Wind and Structures
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    • 제37권4호
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    • pp.289-302
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    • 2023
  • Insulating glass units (IGUs) have been widely used in buildings in recent years due to their superior thermal insulation performance. However, because of the panel reciprocating motion and fatigue deterioration of sealants under long-term wind loads, many IGUs have the problem of early failure of watertight properties in real usage. This study aimed to propose a statistical method for wind-induced deflection of IGU panels during the whole life service period, for further precise analysis of the accumulated fatigue damage at the sealed part of the edge bond. By the estimation of the wind occurrence regularity based on wind pressure return period, the events of each wind speed interval during the whole life were obtained for the IGUs at 50m height in Beijing, which are in good agreement with the measured data. Also, the wind-induced deflection analysis method of IGUs based on the formula of airspace coefficient was proposed and verified as an improvement of the original stiffness distribution method with the average relative error compared to the test being about 3% or less. Combining the two methods above, the deformation of the outer and inner panes under wind loads during 30 years was precisely calculated, and the deflection and stress state at selected locations were obtained finally. The results show that the compression displacement at the secondary sealant under the maximum wind pressure is close to 0.3mm (strain 2.5%), and the IGUs are in tens of thousands of times the low amplitude tensile-compression cycle and several times to dozens of times the relatively high amplitude tensile-compression cycle environment. The approach proposed in this paper provides a basis for subsequent studies on the durability of IGUs and the wind-resistant behaviors of curtain wall structures.

리브플러스 PC슬래브의 수평전단강도 평가 (Evaluation on the Horizontal Shear Strength of Precast Concrete Slab with the Inverted-Rib-Plus)

  • 박금성;이상섭;최윤철
    • 한국구조물진단유지관리공학회 논문집
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    • 제15권6호
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    • pp.156-165
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    • 2011
  • 본 연구는 PC와 RC부분이 만나는 접합면에 대한 구조적 거동과 수평 전단강도 평가를 위한 실험적 연구이다. 접합면에서의 수평전단 내력은 접합면의 거칠기나 전단보강근 유무에 따라 결정되어진다. 본 연구에서는 전단 보강근의 형상이 루프형과 래티스형로 구분하고, 보강근 간격 등에 따라 총 4개의 수평전단강도 실험체를 제작하여 실험을 수행하였다. 실험결과, 접합면에서 수평전단 강도는 수직방향 변형에 의해 지배됨을 알 수 있었다. 보강근 형상에 따른 비교 결과, 루프형의 실험체가 평균 초기균열하중, 평균 최대하중 및 접합면의 평균 초기강성 측면에서 각각 33.7%, 45.9%와 55.2%정도 큰 것으로 나타났다. 현행의 국내 전단강도 평가식과 비교한 결과, 루프형 전단보강 실험체는 2.32~4.23배, 래티스형 전단보강 실험체는 1.65~3.06배 상회하는 것으로 나타났다. 따라서 접합면의 거동이나 구조설계기준에 의한 내력이 안전측으로 평가되어 현장에 적용하는 데에는 별다른 문제는 없는 것으로 판단된다.

무등산국립공원 입석대 주상절리대에 대한 물리역학적 특성 (Physical and Mechanical Properties on Ipseok-dae Columnar Joints of Mt. Mudeung National Park)

  • 고진석;김마루찬;노정두;강성승
    • 지질공학
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    • 제26권3호
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    • pp.383-392
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    • 2016
  • 본 연구는 무등산국립공원 주상절리대 중 입석대 주상절리대를 대상으로 물리역학적 특성을 살펴보았다. 이를 위하여 무등산응회암에 대한 물리적 및 역학적 성질과 불연속면 특성, 주상절리대 주변의 진동 및 국지 기상 측정, 그리고 주상절리대 자체하중에 의한 지반변형을 살펴보았다. 물리적 성질의 경우 평균 공극률은 0.65%, 평균 비중은 2.69, 평균 밀도는 2.68 g/cm3, 평균 종파속도는 2411 m/s로 나타났다. 역학적 성질의 경우 평균 일축압축강도는 323MPa, 평균 탄성계수는 81 GPa, 그리고 평균 포아송비는 0.25로 나타났다. 절리면 전단시험의 경우 평균 수직강성은 3.15 GPa/m, 평균 전단강성은 0.38 GPa/m, 평균 점착력은 0.50 MPa, 그리고 평균 내부마찰각은 35°로 나타났다. 절리면 거칠기를 측정한 결과 거칠기 상수(JRC) 표준도에 따르면 4~6 범위, JRC 차트에 따르면 1~1.5 범위가 우세하게 나타나 약간 거침 상태를 보였다. 또한 주상절리 표면에 대한 실버슈미트해머 반발경도 Q값을 측정한 결과 평균 57(약 90MPa)로 나타났으며, 이는 원래 일축압축강도의 약 28% 수준이다. 입석대 주상절리대 주변의 진동을 측정한 결과 최대 진동값은 0.57 PPV (mm/s)~2.35 PPV (mm/s) 범위를 보여 주상절리대 주변의 탐방객들에 의해 발생되는 진동은 미약한 것으로 나타났다. 주상절리의 표면 및 부근에서 온도, 습도, 풍속 등 국지기상을 측정한 결과 측정 당일의 날씨 영향을 크게 받은 것으로 나타났다. 입석대 주상절리대 자체하중에 의한 지반변형 상태를 수치해석한 결과, 오른쪽 지반에서 최대 변위는 지반거리가 약 2.5m일 때 최대값을 보이며, 6m까지 급격하게 감소하다가 그 이후부터는 미미하게 증가했다. 중간 지반에서 최대 변위는 지반거리가 0~2 m에서 최대값을 보이며, 3 m에서 급격하게 감소하다가 12m에서 미미하게 증가하는 경향을 나타냈다. 그리고 왼쪽 지반에서 최대 변위는 지반거리가 5~6 m일 때 최대값을 보이며, 6~10 m까지 급격하게 감소하다가 그 이후부터는 미미하게 증가하는 것으로 나타났다.

관절와 골 결손을 동반한 견관절 전방 불안정증에 대한 Latarjet 술식 (Latarjet Operation for Anterior Shoulder Instability with Glenoid Bone Defect)

  • 조승현;조남수;이진웅;최일헌;곽윤호;이용걸
    • Clinics in Shoulder and Elbow
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    • 제12권2호
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    • pp.189-198
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    • 2009
  • 목적: 관절와 골 결손을 동반한 견관절 전방 불안정증에 대해 시행한 Latarjet 술식의 임상적 결과를 분석하고자 하였다. 대상 및 방법: 2006년 10월부터 2007년 5월까지 관절와의 현저한 골 결손을 동반한 재발성 전방 불안정증으로 Latarjet 술식을 시행 받은 14예를 대상으로 하였다. 추시 기간은 평균 15개월 (12~19개월), 평균 연령은 29.9세 (19~44세)였고, 남자가 13예였다. 우측이 8예, 좌측이 6예였으며, 우세수가 8예, 비우세수가 6예였다. 6예는 이전에 관절경적 뱅카르트 봉합술을 받은 후 재발하여 Latarjet 술식을 시행한 경우였다. 2예는 간질로 치료받는 환자였다. 결과: Rowe 점수는 수술 전 평균 51.8점에서 수술 후 평균 80.2점으로 향상되었고, 최우수 9예, 우수 4예, 양호 1예였다. Korean shoulder score for instability도 수술 전 평균 61.6점에서 수술 후 평균 82.1점으로 향상되었다. 능동적 전방 거상과 중립위 외회전 운동 범위는 수술후 건측과 비교하여 각각 8도와 16도 감소되었다. 전방 거상력과 중립위 외회전력은 수술 후 건측의 근력에 대해 각각 78.7%와 82.5%였다. 1예에서 간질 발작으로 재탈구가 발생하였고, 1예에서 일시적으로 한차례 아탈구가 있었다. 섬유성 골 유합이 2예, 전이된 오구 돌기의 흡수가 1예, 수술 중 나사에 의한 골 파괴가 1예, 수술 후 일시적 근피 신경 손상이 1예, 수술 후 견관절 강직이 1예 있었다. 결론: Latarjet 술식은 현저한 전방 관절와 골 결손을 동반한 견관절 전방 불안정증에서 수술 후 외회전 운동 범위의 감소를 유발할 수 있으나 관절 호의 길이를 연장시켜 견관절의 기능과 안정을 회복하는데 효과적인 방법이다. 오구 돌기 전이와 관련된 합병증이 많이 발생할 수 있어 이에 대한 주의가 요한다.

경남 일부지역의 농부증 및 하우스증 발생에 미치는 요인분석 (A Study on the causes of farmer's disease and greenhouse disease in a rural area of Kyungnam province)

  • 홍대용;김장락;이명순;강경희;하호성
    • 농촌의학ㆍ지역보건
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    • 제21권2호
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    • pp.173-193
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    • 1996
  • This study was carried out to elucidate the causes of farmer's disease and greenhouse disease in the rural area of Kyungnam province during 1996. 2,171 (69.1%) of the 3,140 adults above 20 years old who had lived in the selected 20 villages in Uiryong County of Kyungnam Province were selected in order to over both residents who live in the green house distracts and conventional rural area. The results were as follows: 1. Among the subjects, the male was 42.2% and female was 57.6%. The average age for the male was 52.3, 55.6 for the female. 2. The proportion of the farmers in the subjects was 81.5%. Among these 78.0% were engaged in the greenhouse farming. 3. Among the eight symptoms of Nofusho(japanese farmer's comples), lumbago was the most frequently complained and followed by shoulder stiffness and parenthesis of hand or foot. 4. The total score of farmer's disease was evidently higher in the female and the older the score was clearly bigger. 5. The prevalence of Nofusho(Japanese farmer's comples)was 26.8% and 43.15% was for the suspected Nofusho. In the male, the prevalence of Nofusho was 13.6% and 40.9% for the suspected Nofusho and in the female 36.5% and 44.7% were shown, comparatively. 6. According to the multiple classification analysis, sex, age, and occupation were selected as significant variables to explain the total score of Nofusho. 7. The correlations between the total score of Nofusho and the number of sick day, working years, and age were significant, comparatively. 8. According to the multiple classification analysis corolling interaction between independent variables, age was the only variable which was significant in the male and age, pesticide work in the female. 9. The score of greenhouse disease was highest in the group who engaged in greenhouse farming and conventional farming(2.76 for male, 3.77 for female) followed by the group who engaged only in greening house farming(2.66 for male, 3.49 for female) and by the group who engaged only in conventional farming(2.27 for male, 3.05 for female) 10. According to the multiple classification analysis with the total score of greenhouse disease as dependent variable, corolling interaction between independent variables, age and pesticide work were revealed as significant variables in the male, while, pesticide work and farming type were significant in the female. According to the above results, the following could be suggested. Because lumbago, shoulder stiffness, paresthesia of hand and foot were the most frequently complained symptoms in the respondent, the development of farming tool to reduce the body burden and periodical physical exercise and rest is highly recommended. It is revealed that both in the farmer' disease and greenhouse disease the score was higher in the female than in the male. So the reasonables measures is recommended to reduce the working hours of the female. Pesticide work was revealed as the significant variable in the female in farmer's disease and both in the male and the female in greenhouse disease. So the development of the safe method of pesticide spraying including safety education should be introduced. Particularly the female should be excluded in pesticide spraying.

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부분구조추정법을 이용한 대형구조물의 효율적인 구조안전도 모니터링 (Efficient Structral Safety Monitoring of Large Structures Using Substructural Identification)

  • 윤정방;이형진
    • 한국지진공학회논문집
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    • 제1권2호
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    • pp.1-15
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    • 1997
  • 본 논문에서는 대형구조물에서 구조물의 안전성 평가와 관련하여 구조물이 국부손상도를 추정하기 위한 효율적인 부분구조추정(Substructural Identification) 기법에 대하여 연구하였다. 먼저, 부분구조 추정법을 위한 모형식을 설정하기 위하여 운동방정식으로부터 부분구조에 대한 계측오차를 처리하기 위한 모형을 포함한 추계론적 자동회귀-이동평균(ARAMX) 모형식을 유도하였다. 추정된 모형식의 계수는 유도된 관계식을 이용하면, 구조손상 평가에 이용될 수 있는 강성행렬로 환산될 수 있다. 본 논문에서 유도된 부분구조 추정법의 가장 큰 장점은 매우 안정되고 정확도가 우수한 구조추정법인 ARMAX 모형식에 기반한 순차적 예측오차 방법을 사용함으로써 다른 방법에 비해 추정의 안정성 및 정확도가 뛰어나다는 것이다. 다음으로는 개발된 부분구조 추정법을 이용하여 구조 손상도 추정이 수행되었다. 손상도 추정을 위하여 앞서 순차적 예측오차 방법을 이용하여 추정된 구조계 현상태의 강성행렬을 바탕으로, 최소지승법을 이용하여 구하는 간접법이 제시되었다. 제시된 방법들의 검증을 위하여 예제해석이 수행되었다. 트러스 및 연속교 모형 그리고 실험적 예제에 적용하여 구조의 강성행렬 및 감쇠행렬을 추정하였다. 이를 바탕으로 손상도 추정방법이 검증되었다. 해석결과로부터, 개발된 방법이 효율적이고 정확도 및 안정성의 측면에서 우수한 성질이 있음을 확인할 수 있다.

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