• Title/Summary/Keyword: Stagnation

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The oriental-western literal study of Crohn's disease (크론씨병(극한성(局限性) 장염(腸炎))에 관(關)한 한의학적(韓醫學的) 고찰(考察))

  • Choi, Chang-Woo;Son, Chang-Gyu;Cho, Chong-kwan
    • Journal of Haehwa Medicine
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    • v.9 no.2
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    • pp.251-268
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    • 2001
  • We arrived at the following conclusion after we have studied crohn's disease through the literatures of western and oriental medicine. 1. Crohn's disease has a characteristic of granulomatous necrosis and cicatricial inflammation which is called by segmental enteritis, granulomatous enteritis. This falls under the category of "Diarrhea", "Dysentery" and is similar to "small intestinal diarrhea", "acute temesmus", "splenic diarrhea" in oriental medicine. 2. In western medicine, the cause of crohn's disease indefinites, but it is presumed immunological unbalance of alimentary canal. In oriental medicine, it is summarized as the abnormal ascending and descending circulation of stomach and splenic energies, the hepatic stagnation, being the lower part of cleaning qi by exogenous disease, dyspeptic convulsion. 3. The presenting symptoms of crohn's disease are intermittent chronic diarrhea, fever, weight loss, abdominal spastic pain or abdominal discomfort. When anyone has a abdominal mass, a rectal abcess, and a rectal constriction by physical examination, we can doubt crohn's disease. 4. The methods of western medical treatment are a suppression of intestinal toxic contents and inflammatory mediator, a supply of nutritive substanceus to intestinal epithelial cell. Oriental medical treatments of these are "inducing diuresis", "warming kidney to reinforce yang", "nourishing qi to invigorate spleen", "eliminatin dampness by cooling" according to syndrome differentiations. As mentioned above, we can confirm possibility of oriental medical treatment that induces recovery of immunologic control function and we need advanced experiment, study, and clinical approach.

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The Effect of Nozzle Collar on Single Phase and Boiling Heat Transfer by Planar Impinging Jet (평면 충돌제트에서 노즐 깃이 단상 및 비등 열전달에 미치는 영향)

  • Shin, Chang-Hwan;Yim, Seong-Hwan;Wu, Seong-Je;Cho, Hyung-Hee
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1452-1457
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    • 2004
  • The water jet impingement cooling is one of the techniques to remove heat from high heat flux equipments. We investigate the local heat transfer of the confined water impinging jet and the effect of nozzle collar to enhance the heat transfer in the free surface jet and submerged jet. Boiling is initiated from the furthest downstream and the wall temperature increase is reduced with developing boiling, forming the flat temperature distributions. The reduction in the nozzle-to-surface distance for $H/W{\leq}1$ causes the significant increases and distribution changes in heat transfer. Developed boiling reduces the differences in heat transfer for various conditions. The nozzle collar is employed at the nozzle exit. The distances from heated surface to guide plate, $H_c$ are 0.25W, 0.5W and 1.0W. The liquid film thickness is reduced and the velocity of wall jet increase as decreased spacing of collar to heated surface. Heat transfer is enhanced for region from the stagnation to $x/W{\sim}8$ in the free surface jet and to $x/W{\sim}5$ in the submerged jet. For nucleate boiling region of further downstream, the heat transfer by the nozzle collar is decreased in submerged jet compare with higher velocity condition. It is because the increased velocity by collar is de-accelerated at downstream.

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Experimental and Numerical Assessment of Liquid Water Exhaust Performance of Flow Channels in PEM Fuel Cells (고분자 전해질 연료전지 유로의 수분배출 특성의 실험 및 해석적 평가)

  • Kim, Hyun-Il;Nam, Jin-Hyun;Shin, Dong-Hoon;Chung, Tae-Yong;Kim, Young-Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.2
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    • pp.85-92
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    • 2009
  • Polymer electrolyte membrane (PEM) fuel cells are a promising technology for short-term power generation required in residential and automobile applications. Proper management of water has been found to be essential for improving the performance and durability of PEM fuel cells. This study investigated the liquid water exhaust capabilities of various flow channels having different geometries and surface properties. Three-pass serpentine flow fields were prepared by patterning channels of 1 mm or 2 mm width onto hydrophilic Acrylic plates or hydrophobic Teflon plates, and the behaviors of liquid water in those flow channels were experimentally visualized. Computational fluid dynamics (CFD) simulations were also conducted to quantitatively assess the liquid water exhaust capabilities of flow channels for PEM fuel cells. Numerical results showed that hydrophobic flow channels have better liquid water exhaust capabilities than hydrophilic flow channels. Flow channels with curved corners showed less droplet stagnation than the channels with sharp corners. It was also found that a smaller width is desirable for hydrophobic flow channels while a larger width is desirable for hydrophilic ones. The above results were explained as being due to the different droplet morphologies in hydrophobic and hydrophilic channels.

Applications of a Coupled Multizone and CFD Simulation to Validate Airflow and Influenza A Contaminant Dispersion in Biosafety Laboratory (생물안전밀폐시설에서 Multizone과 CFD 연동해석에 의한 실내기류 및 Influenza A 오염농도해석)

  • Hwang, Ji Hyun;Hong, Jin Kwan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.588-593
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    • 2014
  • To maintain a negative pressure, the supply, exhaust airvolume are adjusted by setting volume damper and the infiltration through leakage area of the door between rooms in biosafety laboratory. Multizone simulation is useful way to predict room pressure, supply and exhaust air volume. But in a particular room, local change such as airflow and contaminants concentration distribution can not be evaluated unfortunately. Through this study, a coupled multizone and CFD simulation was performed, indoor air flow and local contaminants concentration distribution in a particular room of BSL lab are predicted. The results show that all zones of BSL lab are well ventilated by unidirectional flow without local stagnation. In addition, in case that unexpected biohazard is occured in BSL lab, multizone simulation results about the spread of pollutants along movement of the occupant also show that contaminants concentration is removing totally without the spread of the outside. In conclusion, a coupled multizone and CFD simulation can be applied to interpret differential pressure in room and local change of physical quantity in a particular room such as airflow and Influenza A contaminants concentration distribution. This simulation method is useful to enhance the reliability and accuracy of biosafety laboratory design.

Local heat transfer measurement from a concave surface to an oblique impinging jet (오목한 표면위에 분사되는 경사충돌제트에 대한 국소열전달계수의 측정)

  • 임경빈;김학주
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.3
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    • pp.324-333
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    • 1998
  • Measurements of the local heat transfer coefficients on a hemispherically concave surface with a round oblique impinging jet were made. The liquid crystal transient method was used for these measurements. This method, which is a variation of the transient method, suddenly exposes a preheated wall to an impinging jet while video recording the response of liquid crystal for the surface temperature measurements. The Reynolds number used was 23,000 and the nozzle -to -jet distance was L/d=2, 4, 6, 8 and 10 and the jet angle was $\alpha$=0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$and 40$^{\circ}$. In the experiment, the maximum Nusselt number at all region occurred at L/d(equation omitted)6 and Nusselt number decreases as the inclined jet angle increases. For the normal jet the contours of constant Nusselt number are circular and as the jet is inclined closer and closer to the surface the contours become elliptical shape. The decreasing rate of the Nusselt number at X/d> 0(upstream) on a surface curvature are higher than those on a flate plate and the decreasing rate of the Nusselt number at X/d <0(downstream) on a surface curvature are lower than those on a flate plate. And also, the decreasing rate of local Nusselt number distribution at X/d <0(upstream) exhibit lower than with X/d <0(downstream) as jet angle increases. The second maximum Nusselt number occurred at long distance from stagnation point as jet angle increases.

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Convective Heat Transfer Characteristics on a Plate Cooled by Rectangular Water Jets (사각수분류에 의한 평판상에서의 대류열전달 특성)

  • Kim, Uen-Young;Jeon, Sung-Taek;Park, Jong-Suen;Lee, Doug-Bong
    • Solar Energy
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    • v.15 no.1
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    • pp.53-71
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    • 1995
  • Experiments have been conducted on a planar, free surface jet of water to investigate the effects of aspect ratios(AR=6.67, 15, 26.67), average nozzle velocity($V_0=3.3m/s{\sim}78m/s$) and nozzle-to-plate spacings($Z/W=6{\sim}40$) on the characteristics of heat transfer, when 3 rectangular waterjets impinging on a flat plate which has the uniform heat flux. the scondary peaks which produced by circular jets also produced by rectangular water jets. The position of the scondary peaks depends upon the aspect ratio of nozzle. The heat transfer coefficient was subjected to the influence of aspect ratio. The heat transfer correlations and best position of nozzles which produced maximum heat transfer coefficient at stagnation point are provided.

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A literatual studies on the yupung(油風). (油風의 病因, 病機 및 治療藥物에 關한 文獻的 考察)

  • Kim, Nam-uk;Roh, Sek-seon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.11 no.1
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    • pp.162-179
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    • 1998
  • In the literatual studies on the yupung(油風), the results were as follows. 1. Yupung(油風) was called 'Quijidu(鬼지頭)', 'Quichedu(鬼剃頭)', 'Ballak(髮落)' etc. It was a localized loss of hair in round or oval ares without any subjective symptom 2. The etiology and pathogenesis of Yupung were disorder of vital energy& blood circulation caused by deficiency of blood and wind-dryness syndrome, energy-stagnation and blood stasis, impairment of the liver & kidney. The treatments of Yupung were invigorating the liver & kidney, clearing away heat-evil and cooling blood, nourishing the liver & kidney, activating blood circulation to dissipate blood stasis etc, 3. In the frequency of prescription, the most numerous prescription is Shineuingyangjindan(神應養眞丹) and the next are Tonggyuhwalhyultang(通竅活血湯) & Chilbomiyumdan(七寶美髥丹), 4. In the frequency of medicine, the most numerous medicine is Radix Angelicae Sinensis(當歸) and the next are Rhizoma Rehmanniae Praeparatae(熟地黃) & Rhizoma Ligusiici Chuanxiong(川芎). 5. In classification of drug action, medicines of clearing away wind-heat evil and invigorating yin used to be very busy. 6. In classification of four characters, the most parts are warm medicine. 7. In classification of five tastes, the most numerous tastes are sweet and bitter tastes. 8. In classification of toxicity, the most is non-toxic medicines. 9. In classification of the channel distribution, the most is the medicine that belongs to liver channel. 10. In acupuncture theraphy, it was used 'GV20(百會)', 'G20(風池)', 'GV16(風府)', 'GV14(大椎)', 'LI4(合谷)' etc. in body acupuncture, was used 'S25(天樞)', 'GV14(大椎)', 'B13(肺兪)', 'LI11(曲池)' etc. in moxibustion.

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Policy direction of private security industry in Korea : Through analysis of the courseto amend private security law (우리나라 시큐리티산업의 정책 방향 : 경비업법 개정 과정 분석을 통하여)

  • Seo, Jin-Seok
    • Convergence Security Journal
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    • v.11 no.5
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    • pp.41-51
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    • 2011
  • The objective of this study is to generally check the present situation of private security industry by analyzing the current situation of private security industry in Korea so as to find which policy base is reflected to amend law by analyzing the amendment process of private security law in order to suggest policy direction of private security industry in Korea. Viewing through amendment process of private security law, enhancing publicity and enterprise are not judged to form any definite policy base. They are merely interpreted to partially reflect enterprise under the strong base of publicity. Such policy base may cause overall stagnation of private security industry. For sound development of private security industry, it is required to get out of the existing policy direction so as to change policy base to the direction of enhancing enterprise of private security industry. The power of police for instruction and supervision should be largely transferred to Korea Security Association so as to cultivate autonomous purifying function of private security industry. Police should strive to develop policy in the level of joint production of security service.

Market Entry Decision Model in Global Construction Market Using Real Options Game (실물옵션 게임을 활용한 해외건설시장 진출모형에 관한 기초연구)

  • Kim, Du-Yon;Kim, Byoung-Il;Han, Seung-Heon
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.652-655
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    • 2007
  • Due to stagnation of domestic market, increasing number of domestic construction companies started to make inroads into foreign market recently. Yet compared to domestic market, there are much more risks in the foreign market which companies may confront. So deliberate and rational decision making skills are required. Accordingly, there has been many researches which analyzed the risk of individual markets and also studies covering decision support models. In this study, we suggest a model concerning financial issues when branching out into a new market, specially in the construction companies' point of view. For this we used a real options game which shows real competition status of a new market and deduced a feature of that market, Upon these results, we also suggest a model which helps firms to decide whether investing in the expansion is smart action or not. The model developed in this study is made in specific circumstances of limited conditions. The future study makes more realistic models considering subjects like disproportion in information and generalization of competing companies.

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The Change of Flow Characteristics in Lateral Aneurysm Models for Different Coil Locations (코일 위치에 따른 측방 동맥류 내부 혈류 유동의 변화)

  • 이계한;송계웅;변홍식
    • Journal of Biomedical Engineering Research
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    • v.23 no.5
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    • pp.375-383
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    • 2002
  • Aneurysm embolisation method using coils have been widely used. Micro coils are introduced via a small catheter, and are packed inside of aneurysm sac, which induces intraaneurysmal flow stagnation and thrombus formation. When partial blocking of an aneurysm is inevitable, the location of coils is important since it changes the flow patterns inside the aneurysm, which affect the embolisation process. We measured the flow field inside the partially blocked lateral aneurysm models in vitro, and tried to suggest the effective locations of coils for aneurysm embolisation. Velocity fields are measured using a particle image velocitimeter for different coil locations- proximal neck, distal neck, proximal dome and distal dome. Flow into the aneurysm sac was significantly reduced in the distally blocked models, and coils at distal neck blocked inflow more effectively comparing to those at distal dome. This study suggests that distal neck should be the most effective location for aneurysm embolisation.