• 제목/요약/키워드: Stress Fields

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Analysis of Studies on Sagunja-tang(Sijunzi-tang) to Establish the Fundament for Evidence Based Medicine (EBM 기반구축을 위한 사군자탕 연구 문헌 정량 분석)

  • Kim, Jung-Hoon;Lee, Jun-Kyoung;Shin, Hyeun-Kyoo
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.24 no.2
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    • pp.206-219
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    • 2010
  • To establish the fundament for EBM of Traditional Korean Medicine, the papers on Sagunja-tang(Sijunzi-tang) frequently used in medical institutions of Traditional Korean Medicine were analyzed through researching domestic and international papers. The papers were classified by the registration of domestic or international journals, the year of publishment, experimental fields and the kinds of studies on biological activities. Of total 228 papers on Sagunja-tang(Sijunzi-tang), 121 volumes were selected according to creteria. 47 volumes were published in domestic journals, 71 in Chinese journal, 2 in Japanese journal, and 1 in Taiwan journal. The papers on instrumental analyses were preceeded by HPLC, MS, GC with standard compounds of herbal medicine in Sagunja-tang(Sijunzi-tang). The papers on biological activities of Sagunja-tang(Sijunzi-tang) showed improvement of gastrointestinal activity and blood circulation, immunoactivity, anti-cancer, anti-oxidant, anti-fatigue, anti-stress, pharmacokinetics, hepatic protection, radioprotection, muscular activity, hematopoiesis and nontoxical effect. Further studies including gastrointestinal disorder, immune related disease, cancer, oxidative injury and pharmacokinetic study need to be preceeded to establish the fundament for EBM of Sagunja-tang(Sijunzi-tang).

Relationship Between Dietary Consciousness of Housewives and Their Attitude of Households - in Puchon City - (부천 지역 주부의 식문화 의식과 가사행동과의 관계)

  • Koh, Kyung-Hee
    • Journal of the Korean Society of Food Culture
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    • v.14 no.3
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    • pp.211-224
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    • 1999
  • The purpose of this study was to investigate the understanding of dietary consciousness and define the relationship of housewife attitude of middle class residence in Puchon city. Questionnaires were collected 282 housewives in Puchon city. Data were analysed with SAS software package for F-test and Duncan's multiple range test. The main findings of the research were as follows: The food related perchasing place was supermarket(91%), ordinary market(77%), department store(68%), special store(58%), common purchase(37%), convenience store(22%) and communication marketing(13%). The clothing perchasing place showed in the order of department store(71%), special store(65%), ordinary market(52%), common purchase(23%), supermarket(18%), convenience store(15%) and communication marketing(10%). Dietary cosciousness of housewife on foods, clothing, and housing related items was significantly different, specially 20's housewife was concerned about foods and 30's housewife was housing(p<0.05). The behavior consciousness of housewife was significantly different between age, education level, family type and income(p<0.05). Highly educated housewife showed a tendency to spend money and times for food related fields, and to buy clothes in a department store for breaking stress(p<0.05). However, low education level and extended family type housewife got more conservative consciousness on traditional fermented food making(p<0.05). Most of young housewife answered that the making of bread, cookies, soybean paste soup, children clothes and handicraft led to positive consciousness(p<0.05). Especially high life satisfaction housewife preferred to make a dosirak(lunch box), dinner, children clothes and handicraft(p<0.05).

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A Method to Protect Mine Workers in Hot and Humid Environments

  • Sunkpal, Maurice;Roghanchi, Pedram;Kocsis, Karoly C.
    • Safety and Health at Work
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    • v.9 no.2
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    • pp.149-158
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    • 2018
  • Background: Work comfort studies have been extensively conducted, especially in the underground and meteorological fields resulting in an avalanche of recommendations for their evaluation. Nevertheless, no known or universally accepted model for comprehensively assessing the thermal work condition of the underground mine environment is currently available. Current literature presents several methods and techniques, but none of these can expansively assess the underground mine environment since most methods consider only one or a few defined factors and neglect others. Some are specifically formulated for the built and meteorological climates, thus making them unsuitable to accurately assess the climatic conditions in underground development and production workings. Methods: This paper presents a series of sensitivity analyses to assess the impact of environmental parameters and metabolic rate on the thermal comfort for underground mining applications. An approach was developed in the form of a "comfort model" which applied comfort parameters to extensively assess the climatic conditions in the deep, hot, and humid underground mines. Results: Simulation analysis predicted comfort limits in the form of required sweat rate and maximum skin wettedness. Tolerable worker exposure times to minimize thermal strain due to dehydration are predicted. Conclusion: The analysis determined the optimal air velocity for thermal comfort to be 1.5 m/s. The results also identified humidity to contribute more to deviations from thermal comfort than other comfort parameters. It is expected that this new approach will significantly help in managing heat stress issues in underground mines and thus improve productivity, safety, and health.

Preparation and Thermal Performance Evaluation of Heat Storage paint with MPCM for Reducing Urban Heat Island Effect (도시 열섬현상 저감을 위한 MPCM 적용 축열도료 제조 및 열적성능 평가)

  • Jeong, Su-Gwang;Kang, Yujin;Wi, Seunghwan;Chang, Seong Jin;Kim, Sumin
    • Journal of the Korean Solar Energy Society
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    • v.35 no.4
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    • pp.17-24
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    • 2015
  • The formation of heat islands causes high energy demand for space cooling and peak cooling loads in conditioned buildings. High-temperature fluctuations on a building roof may cause mechanical stress and increase surface deterioration. Thermal energy storage (TES) systems using microencapsulated phase-change materials (MPCMs) have been recognized as one of the most advanced energy technologies for enhancing the energy efficiency and sustainability of buildings. In this study, we prepared MPCM/paint composites for mitigating the heat island effect and reducing peak temperature. In addition, we carried out thermal and physical analysis of prepared MPCM composite samples by means of SEM, FTIR spectroscopy, DSC, and TGA. Further, we evaluated the dynamic heat transfer performance of heat-storage tiles painted with 10 g of heat-storage paint. From the obtained results, we deduced that MPCM/hydrophilic paint composites are more applicable to various fields, including the building sector, than MPCM/hydrophobic paint composites. On the basis of SEM and FTIR spectroscopy results, we concluded that materials with hydrophilic properties are more compatible with MPCMs than those with hydrophobic properties. In addition, DSC analysis results revealed that MPCM/hydrophilic paint composites have better compatibility, higher latent heat capacity, and better thermal properties than other composites. TGA results showed that hydrophilic-paint-based composites have higher thermal durability than hydrophobic-paint-based composites. Finally, a lot of MPCM-loaded heat-storage tiles showed lower peak temperatures at all measurement positions.

Numerical Simulation of Bullet Impact for Fuel Cell of Rotorcraft (회전익항공기용 연료셀 피탄 수치모사 연구)

  • Kim, Hyun-Gi;Kim, Sung Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.5
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    • pp.405-411
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    • 2012
  • Inside a rotorcraft fuel cell, pipes and components are located for fuel storage and fuel supply into the engine. Utility helicopters, operated in battle fields, fly at lower altitude compared to fixed-wing aircraft and hence are more likely to be exposed to gunfire. Since internal pressure of fluid increases when hit, the effect on LRU due to increase in pressure must taken into account when designing the aircraft for survivability. However, it is costly and time consuming to manufacture a fuel cell for gunfire test, and due to constraints from usage of live ammunition, related data gathered through numerical simulation is needed. In this study, numerical simulation on rotorcraft fuel cell exposed to gunfire was carried out using Autodyn to analyze bullet movement inside the fuel cell after hit, and internal pressure of fluid and equivalent stress on fuel cell assessed.

The Effects of Flow Wave form on the Flow Characteristics in Tapered Vascular Grafts (유량 파형이 데이퍼형 인조혈관 유동에 미치는 영향)

  • Lee, H. C.;Seok, K. W.;Jon, C. W.;Lee, J.;Lee, Y. S.;Kim, S. H.
    • Journal of Biomedical Engineering Research
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    • v.17 no.3
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    • pp.337-346
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    • 1996
  • The patency of small size vascular grafts is poor, and the blood flow characteristics in the artery graft anastomosis are suspected as one of the important factors influencing intimal hyperplasia. Disturbed flow patterns caused by sixte and compliance mismatch generate unfavorable flow environment which promotes intimal thickening. Tapered vascular yuts are suggested in order to reduce sudden expansion near the anastomosis. The photochromic flow visualization method is used to measure the flout fields in the end-to-end anastomosis model under the carotid and femoral artery flow wave form. The results show that flow disturbance near the anastomosis is diminished in the tapered grafts comparing to the tubular graft. As the divergent ang1e decreases, we can reduce the low and oscillatory wall shear stress zone which is prone to intimal hyperplasia. The flow wave form effects the wall shear rate dis- tribution significantly. The steep deceleration and back flow in the femoral flow wAve form cause low mean wall shear rate and high oscillatory shear index.

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Distribution of Welding Residual Stresses in T-joint Weld with Root Gap (루트부 갭이 있는 양면 필릿용접 이음부의 용접잔류응력 분포)

  • H.S. Bang;S.H. Kim;Y.P. Kim;C.W. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.39 no.3
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    • pp.81-88
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    • 2002
  • The root joint in the welding structures are apt to failure by the stress concentration which is occurred by the external force. Therefore, in the safety and reliability of structure, the complete penetration joint welding which are obtained by the groove welding with edge preparation is generally required. Nevertheless, fillet T-joint welding without edge preparation is often carried out in the fields to reduce working time and consumption of welding electrode, however, this process is likely to produce inadequate joint penetration such as root gap. In this paper, the focus of research is to investigate distribution of welding residual stresses in the plate(or flange) and web of T-joint weld, and especially in the near of root gap notch that is due to incomplete joint penetration. For the analysis, we have chosen model of T-joint weld in the cases of single and multi-pass welding with submerged arc welding and analyzed model by using finite element programs considering the heat conduction and thermal elasto-plastic theory.

Behavior of concrete cylinders confined by jacketing with lateral confining stress (횡방향 구속응력에 의한 자켓팅-콘크리트 공시편 거동)

  • Cho, Sung-Chul;Choi, Eun-Soo;Chung, Young-Soo;Cho, Baik-Soon;Choi, Ji-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.157-160
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    • 2008
  • The confined concrete subjected multi-axil stresses have been known as the strength of concrete increases significantly. Many researchers have studied in confining effect of concrete, and now are studying in many fields. Lap splices were located in the plastic hinge region of most bridge piers that were constructed before the adoption of the seismic design provision of Korea Highway Design Specification on 1992. But sudden brittle failure of lap splices may occur under loading. This study introduces a new method to retrofit RC bridge columns with lap splice which do not have enough ductility during an earthquake. The new method use mechanical external pressure and steel plates around RC columns. The jacketing built following the new method shows good results of increasing the compressive strength and ductility of concrete cylinders. The thicker steel jacket shows larger compressive strength, however, the ductility at failure depends on the welding quality of steel jackets. In this study, The effect of the new method is verified through comparing the results of the compressive tests and analysis results.

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A Literature Review on the Clinical Application of Microcurrent Electrical Neuromuscular Stimulation(MENS) : articles published for recent 10 years (미세전류치료의 최근 임상연구논문 고찰)

  • Ryu, Ji-Mi;Kim, Sung-Soo;Kim, Kyoung-Seok;Chung, Seok-Hee
    • Journal of Korean Medicine Rehabilitation
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    • v.18 no.4
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    • pp.121-133
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    • 2008
  • Objectives : MENS was used for wound healing and pain relief using bioelectric property. There are many articles on in vivo and clinical research. This article reviews articles on MENS published for recent 10 years to consider effectiveness of MENS and other fields to applicate MENS. Articles were collected from MAR, 2008 to JUN, 2008. Methods : We searched Pubmed, KSI, KERIS, KMBASE, and National assembly library using "Microcurrent Electrical Neuromuscular Stimulation" and classified the articles into subsets of foreign, Korean and wound healing, pain, relief, and increasing the range of movement(ROM). Also we evaluated their values according to the Jadad scale. Results : A total of 18 articles (Foreign-9, Korean-9) reconfirmed that MENS reduces pain, increases wound healing, ROM, and strength of muscle. In addition, MENS has effect on stress-hormone and various pain like low back pain, acute lateral epicondylitis, and plantar fascitis. And there are various styles developed. However, there is no standard protocol so the user is usually in trouble at clinic. Conclusions : MENS may be have application to various pain diseases, and further studies analysing its effectiveness are needed.

Nonlinear transient analysis of FG pipe subjected to internal pressure and unsteady temperature in a natural gas facility

  • Soliman, Ahmed E.;Eltaher, Mohamed A.;Attia, Mohamed A.;Alshorbagy, Amal E.
    • Structural Engineering and Mechanics
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    • v.66 no.1
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    • pp.85-96
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    • 2018
  • This study investigates the response of functionally graded (FG) gas pipe under unsteady internal pressure and temperature. The pipe is proposed to be manufactured from FGMs rather than custom carbon steel, to reduce the erosion, corrosion, pressure surge and temperature variation effects caused by conveying of gases. The distribution of material graduations are obeying power and sigmoidal functions varying with the pipe thickness. The sigmoidal distribution is proposed for the 1st time in analysis of FG pipe structure. A Two-dimensional (2D) plane strain problem is proposed to model the pipe cross-section. The Fourier law is applied to describe the heat flux and temperature variation through the pipe thickness. The time variation of internal pressure is described by using exponential-harmonic function. The proposed problem is solved numerically by a two-dimensional (2D) plane strain finite element ABAQUS software. Nine-node isoparametric element is selected. The proposed model is verified with published results. The effects of material graduation, material function, temperature and internal pressures on the response of FG gas pipe are investigated. The coupled temperature and displacement FEM solution is used to find a solution for the stress displacement and temperature fields simultaneously because the thermal and mechanical solutions affected greatly by each other. The obtained results present the applicability of alternative FGM materials rather than classical A106Gr.B steel. According to proposed model and numerical results, the FGM pipe is more effective in natural gas application, especially in eliminating the corrosion, erosion and reduction of stresses.