• Title/Summary/Keyword: direct strength method

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A Study on the Reinforcement of Rock Faults by Grouting (암석 절리면의 그라우팅에 의한 보강에 관한 연구)

  • Chun, Byung-Sik;Choi, Joong-Keun
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.4
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    • pp.45-51
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    • 2003
  • Grouting materials in rock is grouted as vein type along the fault surface by the other way for soil and allow a change of characteristics in rock faults as a result of that. Therefore the deformation characteristics of rock faults after grouting differ as a direction and characteristic of grouted fault and stress condition of field rock. Thereby it must be analyzed the effect for deformation of rock according to characteristics of rock faults and characteristics of grouting materials to accurately evaluate the reinforced effect by grouting. But grouting method used in field until present depends on experience of workers, and inspection for those effects are evaluated by measurement of elastic wave velocity, permeability tests and etc. in field. In this study, it was investigated that the effects for shear characteristics of maximum shear strength, residual shear strength and etc. by comparison and analysis of test results which were worked by direct shear tests of rock faults with changing a type of grouting materials and the grouting depth(t) for average width(a) of fault surface roughness when OPC(Ordinary Portland Cement) and Micro cement was grouted in fault surface of field rock to evaluate characteristicsof the shear deformation for rock fault surface of dam by grouting.

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The Development and Effect of a Tailored Exercise Program on Physical Fitness in Patients with Parkinson's Disease (파킨슨병 맞춤운동프로그램의 개발 및 신체기능에 대한 효과)

  • Sohng, Kyeong-Yae;Moon, Jung-Soon;Lee, Kwang-Soo;Choi, Dong-Won
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.13 no.3
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    • pp.390-400
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    • 2006
  • Purpose: To develop & to examine the effect of a Tailored Exercise Program (TEP) on physical fitness in patients with Parkinson's disease (PD). Method: In a two-group pre-and post-test design, from a total 41 participants. 21 were assigned th the experimental group find the remainder to the control group. The experimental group participated in a 4-day a week, 8 week program in which one session a week was by direct instruction with the self-help group and two sessions a week were by videotaped instruction at home by themselves. The control group did not receive any intervention. Results: The eight week TEP in patients with PD was found to be significantly effective in enhancing muscle strength, ankle flexibility, and balance. However instrumental activities of daily living was not changed by the intervention. Conclusion: These results suggest that TEP can have an effect on physical fitness in patients with PD. Further research with a larger sample and for a longer follow up period is needed to expand our understanding of the effects of TEP for patients with PD.

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INTERACTIONS WITH EDDIES IN THE UPSTREAM OF THE KUROSHIO AS SEEN BY THE HF RADAR AND ALTIMETRY DATA

  • Ichikawa, Kaoru;Tokeshi, Ryoko
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.969-972
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    • 2006
  • The long-range High-Frequency (HF) ocean radar system has observed surface velocity field in the upstream of the Kuroshio north of Ishigaki Island and east of Taiwan since 2001. Applying a new method to extract geostrophic velocity component from the HF surface velocity data with the aid of satellite-born wind data, time series of daily surface geostrophic velocity field has been determined. Despite limited width of the study area of the HF radar, analysis of the sea surface height anomaly determined from the satellite altimetry data in a wider area can provide estimated dates of arrival of mesoscale eddies in the study area of the HF radar. Variations of the Kuroshio position and strength are studied in detail for these cases of interaction with mesoscale eddy, although number of occurrence of direct interaction with the Kuroshio in the study area is not statistically enough. For example, when an anticyclonic eddy approaches to the Kuroshio, the Kuroshio axis is found tend to move northward, keeping away from the approaching eddy from the east.

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Effects of maleic anhydride content on mechanical properties of carbon fibers-reinforced maleic anhydride-grafted-poly-propylene matrix composites

  • Kim, Hyun-Il;Han, Woong;Choi, Woong-Ki;Park, Soo-Jin;An, Kay-Hyeok;Kim, Byung-Joo
    • Carbon letters
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    • v.20
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    • pp.39-46
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    • 2016
  • In this work, the effects of maleic anhydride (MA) content on mechanical properties of chopped carbon fibers (CFs)-reinforced MA-grafted-polypropylene (MAPP) matrix composites. A direct oxyfluorination on CF surfaces was applied to increase the interfacial strength between the CFs and MAPP matrix. The mechanical properties of the CFs/MAPP composites are likely to be different in terms of MA content. Surface characteristics were observed by scanning electron microscope, Fourier transform infrared spectroscopy, and single fiber contact angle method. The mechanical properties of the composites were also measured by a critical stress intensity factor (KIC). From the KIC test results, the KIC values were increased to a maximum value of 3.4 MPa with the 0.1 % of MA in the PP, and then decreased with higher MA content.

A new strain-based criterion for evaluating tunnel stability

  • Daraei, Ako;Zare, Shokrollah
    • Geomechanics and Engineering
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    • v.16 no.2
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    • pp.205-215
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    • 2018
  • Strain-based criteria are known as a direct method in determining the stability of the geomechanical structures. In spite of the widely use of Sakurai critical strain criterion, it is so conservative to make use of them in rocks with initial plastic deformation on account of the considerable difference between the failure and critical strains. In this study, a new criterion has been developed on the basis of the failure strain to attain more reasonable results in determining the stability status of the tunnels excavated in the rocks mostly characterized by plastic-elastic/plastic behavior. Firstly, the stress-strain curve was obtained having conducted uniaxial compression strength tests on 91 samples of eight rock types. Then, the initial plastic deformation was omitted making use of axis translation technique and the criterion was presented allowing for the modified secant modulus and by use of the failure strain. The results depicted that the use of failure strain criterion in such rocks not only decreases the conservativeness of the critical strain criterion up to 42%, but also it determines the stability status of the tunnel more accurately.

Contact Stress Analysis of Stick Type Ignition Coil Jacket PET (Stick Type Ignition Coil Jacket PET의 접촉응력 해석)

  • Kim Yang-Sul
    • Journal of the Korean Society of Safety
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    • v.20 no.1 s.69
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    • pp.1-6
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    • 2005
  • Stick type ignition coil is new development that connect directly with ECU(Electronic control unit), without needing a spark plug cable and distributor. Glass-fiber reinforced ploymeric composites provide the desirable properties of high stiffness and strength as well as low specific weight. Stick type ignition coil jacket is using PBT CF30 resin. PBT CF30 resin is a kind of electric insulation which is a superior engineering plastic that is used to prevent the leakage of the electrical current. If PET receive a mistake of design or excessive force when HV terminal oppress on jacket, it can happen to crack. Local stress concentrations occurring on the contact surface, the contact phenomenon becomes a direct cause to the wear and failure of mechanical structures. When it is cracked, it can allow a leakage of the electrical current. So, in this study, we analyze the contact stress to PBT jacket using ANSYS program, when HV terminal oppress on jacket. We suppose PBT to be Jacket and we analyzed contact stress that happens in PET like PBT analysis method. We compared the use of PBT and PET.

Effect of Foaming Temperature on Cell Structure of 606X Series Aluminum Alloy Metallic Foams (Foaming 온도에 따른 606X계 발포 알루미늄의 제조 특성)

  • Song, Yeong-Hwan;Park, Soo-Han;Jeong, Min-Jae;Kang, Kwang-Jung;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.28 no.2
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    • pp.79-84
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    • 2008
  • Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

Detail-design Guidance for the Openings on the Web Structure Supporting the Deck (갑판지지 웨브 구조에서의 개구부 상세설계기준 정립)

  • Kim, Sung-Chan;Lee, Kyung-Seok;Song, Jae-Young;Kim, Kyung-Su
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.6
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    • pp.612-618
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    • 2007
  • There are a lot of openings, holes and slots in ship structural members. It is not easy to solve the troubles around the openings adequately at the detail design stage, because there are a lot of concerning locations. There are not also clear design rules of classification societies and it is not possible to apply direct calculation for all the concerning members. Therefore, it is necessary to set up simplified approach such as a standard or guidance in order to decide the opening design quickly. For this study, guidance and regulations of each classification and several companies were surveyed. Grillage analysis and the refined mesh method were used to evaluate the strength around hole considering boundary condition and more detailed member arrangement. As a result, the standard for opening design was established and verified.

A Study on the Evaluation of The Load Resistancy of Lightweight Wall against Wall Attachments through Field Tests (현장실험을 통한 건식경량벽체의 부착물에 대한 하중 저항성 평가에 관한 연구)

  • Kim, Tae-Ik;Lee, Ju-Min;Kim, Sang-Heon;Choi, Soo-Kyung;Seo, Chee-ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.183-184
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    • 2015
  • Recent structural approach of the House of Commons has been an increase in demand for dry wall light due to a change in load bearing composite structure of a flat plate type structure under the name of long-life housing, attach the attachment to the wall as the needs of the residents of reserved space increases things that are on the rise. However, depending on the strength of collapse accidents is shown wall and recent wall deposits are required, a load resistance evaluation method of the deposit of the need is the situation. Therefore, in this study, for the evaluation of the evaluation of dry lightweight wall as widely used gypsum board and ALC lightweight wall of two types of laboratory the wall through the previous studies to be installed in direct co-housing to the target and field experiments I want to evaluate the different points.

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Determinants of Self-rated Health in Sedentary Older Adults (규칙적 신체활동을 수행하지 않는 고령자의 주관적 건강평가에 영향을 미치는 요인)

  • Hong, Seung-Youn
    • Korean Journal of Health Education and Promotion
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    • v.25 no.4
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    • pp.67-82
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    • 2008
  • Purpose: The objective of this study were to examine the determinants of self-rated health, specially focused on the effect of functional capacity of community dwelling sedentary older adults on self-rated health. Method: The data has been collected from 654 community-dwelling sedentary older adults (mean age: 75 years) during the period from April to June in 2007. The data were collected by the in-person interview and direct measurement of functional capacity. The data were analyzed using chi-square test and multiple regression analysis with the SPSS 9.1 program. Result: The elderly rated their health as very good (3%), good (28%), fair (38%), poor (29%0, and very poor (2%). The higher average daily walk minutes ($\beta$=0.12, p<.01), number of chair stand ($\beta$=0.10, p<.05), scores of self-efficacy ($\beta$=0.16, p<.001) and the lower number of disease ($\beta$=-0.44, p<.001) show better self-rated health. Conclusion: Self-rated health is the most commonly used indicators in social epidemiology and geriatric research because it has been known as the good predictor of mortality and reflects health related disability. The finding suggested that daily walking habits, lower body strength, physical self-efficacy should be considered to improve the senior's self-perception of health. The community-based intervention associate increase these factors should be considered.