• 제목/요약/키워드: P loading

검색결과 1,478건 처리시간 0.035초

사용반복하중에 대한 철근콘크리트 보의 피로거동 (Fatigue behavior of RC Beams under High Cycle Loading)

  • 강보순;황성춘
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 추계학술대회논문집 I
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    • pp.499-503
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    • 2001
  • Fatigue behavior of reinforced concrete (RC) elements has been experimentally and analytical investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, strength of concrete and load ratio P/sub u//P/sub o/. The purpose of these studies is to propose an empirical formula for fatigue behavior on basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.

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淸州取水源의 窒素 및 燐濃度에 관한 調査硏究 (A Study on Nitrogen and Phosphorus Concentration in Chung Ju Intake Reservoir)

  • Lee, Yeoung Shin;Lee, Hong Keun
    • 한국환경보건학회지
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    • 제12권2호
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    • pp.27-37
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    • 1986
  • This study was carried out to investigate inflow stream of Chungju intake reservoir and in catchment area, run-off loading amount, distribution of Nitrogen and phosphorus, N/P ratio, correlationship between T-N and chlorophyll a, correlationship between T-P and chlorophyll a, and study of trophic state. Field survey was carried out from June to August, 1985, for the purpose of finding out the nitrogen and phosphorus concentration in Chungju intake reservoir.

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Plasma display panels; problems and their analysis via computer simulations

  • Nagorny, V.P.;Khudik, V.N.;Drallos, P.J.;Shvydky, A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.155-160
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    • 2005
  • Computer simulations of a pdp discharges provide unique information necessary for their analysis, unavailable otherwise. Statistical instability of the ramp discharge and the role of exoemission, nature of striations during sustain discharge, physical mechanism responsible for the propagation of the cathode ionization wave, and line loading effects are just a few examples when simulations can be successfully used.

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다방향 프로세싱을 위한 P2P 검색 알고리즘 제안 (A Suggestion of P2P Search Algorithm for Multidirectional Processing)

  • 김분희
    • 한국컴퓨터정보학회논문지
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    • 제13권7호
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    • pp.109-115
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    • 2008
  • P2P 분산시스템에서 각 피어들은 항상 온라인 상태를 유지하지 않는다. P2P 시스템은 각 피어들은 하나의 시스템의 구성 요소로써 유기적으로 작동되는 일반적인 시스템과 다른 것이다. 이런 경우 P2P 시스템을 이용하는 사용자에게는 신뢰성이 떨어지는 시스템이 될 수 있는 것이다. 이에 많은 P2P 연구에서 이러한 문제를 해결하고자 시도하고 있다. 본 연구에서는 다운로드 되고 있는 자원에 대해 신뢰성 있는 연결을 제공하기 위해 다방향 프로세싱 P2P 검색 알고리즘을 제안한다. 기존 연구에서는 새로운 자원 제공 피어의 선택을 위한 로딩 부담률이 높았는데 본 연구에서는 이를 해결하고자 한다.

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신계념 LNG-RV 운반선의 현황

  • 배병덕
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2007년도 추계학술대회 및 제23회 정기총회
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    • pp.322-324
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    • 2007
  • 최근 엘엔지운반선(LNGC)은 선체의 대형화, DFDE디젤엔진탑재, 재액화설비등의 변화와 함께 해상터미널의 역할을 동시에 할 수 있는 LNG-RV(Regasification Vessel)의 출현을 경험하였으며, 이러한 신계념의 선박의 개발개념, 운항방식 등에 대하여 살펴보도록 한다.

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흰쥐 좌골신경 압좌손상 후 수영운동의 부하에 따른 근육 회복 (Muscle Recovery After Sciatic Nerve Crush Injury in Rats by Different Loading Swimming Exercise)

  • 이민형;김종순
    • 대한물리의학회지
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    • 제8권4호
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    • pp.525-532
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    • 2013
  • PURPOSE: The aim of this study was to compare the effects of different loading swimming exercises on muscle recovery after sciatic nerve crush injury in rats. METHODS: For this study, thirty-one Sprague-Dawley male rats were randomly divided into five groups. There were the negative control group (NCG, n=5), the positive control group (PCG, n=7), the low intensity swimming exercise group (LISEG, n=7), the moderate intensity swimming exercise group (MISEG, n=7) and the high intensity swimming exercise group (HISEG, n=5). Each rat was weighed to determine the lead weight to be attached to the base of its tail. Subsequently, the PCG, the LISEG, the MISEG and the HISEG were underwent standard unilateral sciatic nerve crush. The LISEG (no load), the MISEG (lead weight equivalent to 2% average body mass) and the HISEG (lead weight equivalent to 4% average body mass) were received the 10 minute swimming exercise in a day for 10 days. The NCG and PCG were not received with any therapeutic intervention. The diameter of the calf muscle and the level of serum lactate dehydrogenase (LDH) were measured to detect the effects of the swimming exercise. RESULT: The maximum diameter of the calf muscles was significantly increased after seventh swimming exercise in the LISEG, the MISEG and the HISEG compared with the PCG (p<0.05). However, there was no statistically significant difference between the LISEG, the MISEG and the HISEG. Also, the level of the serum LDH was significantly decreased in the LISEG, the MISEG and the HISEG compared with the PCG (p<0.05). CONCLUSION: Taken together, these results suggest that swimming exercise could accelerate muscle recovery processes after crush injury, but the different intensity of the swimming exercise does not affect healing processes.

Simulation of vibrations of Ting Kau Bridge due to vehicular loading from measurements

  • Au, F.T.K.;Lou, P.;Li, J.;Jiang, R.J.;Zhang, J.;Leung, C.C.Y.;Lee, P.K.K.;Lee, J.H.;Wong, K.Y.;Chan, H.Y.
    • Structural Engineering and Mechanics
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    • 제40권4호
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    • pp.471-488
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    • 2011
  • The Ting Kau Bridge in Hong Kong is a cable-stayed bridge comprising two main spans and two side spans. The bridge deck is supported by three towers, an end pier and an abutment. Each of the three towers consists of a single reinforced concrete mast strengthened by transverse cables and struts. The bridge deck is supported by four inclined planes of cables emanating from anchorages at the tower tops. In view of the heavy traffic on the bridge, and threats from typhoons and earthquakes originated in areas nearby, the dynamic behaviour of long-span cable-supported bridges in the region is always an important consideration in their design. Baseline finite element models of various levels of sophistication have been built not only to match the bridge geometry and cable forces specified on the as-constructed drawings but also to be calibrated using the vibration measurement data captured by the Wind and Structural Health Monitoring System. This paper further describes the analysis of axle loading data, as well as the generation of random axle loads and simulation of vibrations of the bridge using the finite element models. Various factors affecting the vehicular loading on the bridge will also be examined.

Chemical Assessment of Heavy Metal Contamination in Soil

  • Yang, Jae-E.;Choi, Moon-Heon
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 1997년도 총회 및 춘계 학술발표회 논문집
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    • pp.8-11
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    • 1997
  • Current methods of evaluating soil contamination by heavy metals rely on analyzing samples for total contents of metals or quantities recovered in various chemical extracting solutions. Results from these approaches provide only an index for evaluation because these methodologies yield values not directly related to bioavailability of soil-borne metals. In addition, even though concentrations of metals may be less than those required to cause toxic effects to biota, they may cause substantial effects on soil chemical parameters that determine soil quality and sustainable productivity. The objective of this research was to characterize effects of Cu or Cd additions on soil solution chemistry of soil quality indices, such as pH, EC, nutrient cation distribution and quantity/intensity relations (buffer capacity). Metals were added at rates ranging from 0 to 400 mg/kg of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable (strongly adsorbed) fractions. Adsorption of the added metals released cations into soil solution causing increases of soluble cation contents and thus ionic strength of soil solution. At metal additions of 200~400 mg/kg, EC of soil solution increased to as much as 2~4 dS/m; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations (Ca+Mg) than monovalent cations (K+Na) were exchanged by Cu or Cd adsorption. The loss of exchangeable nutrient cations decreased long-term nutrient supplying capacity or each soil. At 100 mg/kg or metal loading, the buffering capacity was decreased by 60%. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu/kg addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.

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Loosening torque of Universal Abutment screws after cyclic loading: influence of tightening technique and screw coating

  • Bacchi, Atais;Regalin, Alexandre;Bhering, Claudia Lopes Brilhante;Alessandretti, Rodrigo;Spazzin, Aloisio Oro
    • The Journal of Advanced Prosthodontics
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    • 제7권5호
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    • pp.375-379
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    • 2015
  • PURPOSE. The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS. Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at $10^6$ cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). RESULTS. The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). CONCLUSION. The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.