• Title/Summary/Keyword: Stagnation Pressure

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The Political Economy of Southeast Asia 2017 (동남아의 정치경제 2017)

  • PARK, Sa-Myung
    • The Southeast Asian review
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    • v.28 no.1
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    • pp.1-20
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    • 2018
  • Southeast Asia witnessed a paradox of political stagnation and economic development in 2017. The 'dual order' of security dependence on America and economic dependence on China was sustained in East Asia. In this regard, Southeast Asia of two faces was quite similar to broader East Asia. On one hand, the old socialist group with totalitarian nostalgia lurked in the buffer zone between totalitarianism and authoritarianism, while the original capitalist group under democratic disguise roamed in the gray zone between authoritarianism and democracy. On the other, the old socialist group with the legacy of the planned economy succumbed to the temptation of the Beijing Consensus on state capitalism, while the original capitalist group with the myth of the market economy was exposed to the pressure of the Washington Consensus on liberal capitalism. The ASEAN Community representing the regional integration of Southeast Asia was caught in the strategic predicament of a looming 'new cold war' between the continental and maritime powers.

Aerodynamic properties of a streamlined bridge-girder under the interference of trains

  • Li, Huan;He, Xuhui;Hu, Liang;Wei, Xiaojun
    • Wind and Structures
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    • v.35 no.3
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    • pp.177-191
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    • 2022
  • Trains emerging on a streamlined bridge-girder may have salient interference effects on the aerodynamic properties of the bridge. The present paper aims at investigating these interferences by wind tunnel measurements, covering surface pressure distributions, near wake profiles, and flow visualizations. Experimental results show that the above interferences can be categorized into two primary effects, i.e., an additional angle of attack (AoA) and an enhancement in flow separation. The additional AoA effect is demonstrated by the upward-moved stagnation point of the oncoming flow, the up-shifted global symmetrical axis of flow around the bridge-girder, and the clockwise-deflected orientation of flow approaching the bridge-girder. Due to this additional AoA effect, the two critical AoAs, where flow around the bridge-girder transits from trailing-edge vortex shedding (TEVS) to impinging leading-edge vortices (ILEV) and from ILEV to leading-edge vortex shedding (LEVS) of the bridge-girder are increased by 4° with respect to the same bridge-girder without trains. On the other hand, the underlying flow physics of the enhancement in flow separation is the large-scale vortices shedding from trains instead of TEVS, ILEV, and LEVS governed the upper half bridge-girder without trains in different ranges of AoA. Because of this enhancement, the mean lift and moment force coefficients, all the three fluctuating force coefficients (drag, lift, and moment), and the aerodynamic span-wise correlation of the bridge-girder are more significant than those without trains.

A Literature Review of The Senile Hypotension (노인(老人) 저혈압(低血壓)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Kwak, Ik-Hoon;Kim, Jong-Dae;Jeong, Ji-Cheon
    • The Journal of Dong Guk Oriental Medicine
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    • v.4
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    • pp.161-187
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    • 1995
  • This study was perfomed to investigate causes of the senile hypotension, pathogenic mechanism, symptoms, and therapies through medical literatures, recent chinese medical literatures and chinese medical journals. The results are as follows ; 1. The senile hypotension has major symptoms of dizziness, weakness, syncope, palpitation, shortness of breath, and deficiency of Qi. Additionally, it has minor symtoms of letharhy, isomnia, tinnitus, amnesia etc... 2. The prodromal symptoms of Kwul and Kwul are relating to the symptoms of tachycardia, facial pallor, sweating, anxietas, ambiguous consciousness, and fainting. Weakness and dizziness due to deficiency make the symptoms of exhaustion, fatigue, vertigo, lethargy, and brachycardia. 3. The most principal cause of the senile hypotension is deficiency of Shen due to aging, congenital deficiency, and chronic illness. The rest of causes are defciency of Qi and blood, phlegm of retention, stagnation of Qi, blood stasis, blood prostration etc... In the view of the occidental meicine, the causes of the senile hypotension came from the reduction of cardiac output, the decretion of cardiovascular system's extention due to aging, hereditary factor, secondary factor due to exsanguination, diabetes mellitus, C.V.A etc..., and factor of neurogenic system's degeneration. 4. The principal pathogenic mechanisms are the insufficiency of Xing-Yang, the deficiency of Qi in middle jiao, and deficiency of Shen-Qi. The rest of mechanisms are the deficiency of both Qi and blood, stagnation of the Gan-Qi, and the deficiency of Gan and Shen. Zang-Pu Organs have something to do with Xing, Bi, and Shen. 5. As principal therapies, there are warming and recuperation the Xing-Yang, strengthing the middle-jiao and replenishing Qi, replenishing vital essence to tonify the Shen, and warming and recuperation the Shen-Yang. Additionally, the therapies of invigorating the Bi and relieving mental stress, strengthning the Bi and tonifing the Shen, invigorating Qi and nourishing Yin, soothing the Gan and regulating the circulation of Qi, and tonifing the Shen and nourishing the Gan help the cure of the senile hypotension. In prescriptions there are Baohe Yuan Tang, Buzhong Yigi Tang, Zuoguei Yin, Yougui Yin, Guipi Tang, Zhu Fu Tang, Shengmai San, Sini San, and Qi Ju Dihuang Wan. The medical herbs of Astragali Radix, Codonopsitis Pilosulae Radix, Ginseng Radix, Aconiti Tuber, Ephedrae Herba, Cinnamomi Ramulus, Cinnamomi Corfex Spissus, Zingiberis Rhizoma, Polygalae Radix, Liriopis Tuber, Polygonati Sibirici Rhifoma, Lycii Fructus, Schizandrae Fructus, and Glycyrrhizae Radix can be treated. 6. According to the clinical report, the principal causes are the deficiency of Qi, and insufficiency of Yang which symptoms are dizziness, vitality fatigue and acratia, amnesia, body cold and alger of extremity, spontaneous perspiration, and therady and weak pulse. It was improved by taking WenYang YiQi Tang, Zhu Fu Tang about 20-30 days. The improvement was shown on disappearance of subjective symptoms or the ascending of blood pressure to normal figure, and the rate of improvement was over 70%. 7. As regimens, taking warming and recuperating food(a sheep mutton, juglans regia, chiness date, longan aril etc...) and pungent food(chinese green onion, fress ginger, pipers fructns etc...), doing physical training, not being ill in bed at a long time, and preventing descent of blood pressure coming from sudden change of posture are needed. Additionally, the usage of diuretic, abirritant, and depressor needs to be extra cautious.

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High-Altitude Environment Simulation of Space Launch Vehicle in a Ground-Test Facility (지상시험장비를 통한 우주발사체 고공환경모사 기법 연구)

  • Lee, Sungmin;Oh, Bum-Seok;Kim, YoungJun;Park, Gisu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.11
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    • pp.914-921
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    • 2017
  • The experimental research on a high-altitude environment simulation of space launch vehicle is important for securing independent technologies with launching space vehicles and completing missions. This study selected an altitude of 65 km for the experiment environment where it exceeded Mach number of 6 after the launch of Korean Space Launch Vehicle(KSLV-II). Shock tunnel was used to replicate the flight condition. After flow establishment, in order to confirm aerodynamic characteristics and normal and oblique shockwaves, the flow verification was carried out by measuring stagnation pressure and heat flux of a forebody model, and shockwave stand-off distance of a hemispherical model. In addition, a shock-free technique to recover free-stream condition has been developed and verified. From the results of the three verification tests, it was confirmed that the flow was replicated with the error of about ${\pm}3%$. The error between the slope angle of inclined shockwave of the scaled down transition section model using the shock-free shape and the slope angle of the horizontal plate model, and between the theoretical and the experimental value of the static pressure of the model were confirmed to be 2% and 1%, respectively. As a result, the efficiency of the shockwave cancellation technique has been verified.

Study on the 'Diagnosis and Treatment of Terror and Palpitation due to Fright and the Several Hemorrhagic Diseases' in Synopsis of Golden Chamber (금궤요략${\cdot}$경계토뉵하혈흉만어혈병맥증병치 제십육(第十六)에 대(對)한 연구(硏究))

  • Yun, Ju-Heon;Park, Kum-Sook;Kwon, Mi-Ja;Lim, Dong-Kook;Jeong, Heon-Young
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.1
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    • pp.13-24
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    • 2008
  • This Chapter mentioned Terror and Palpitation due to Fright(驚悸) and Hemorrhagic disease(血證). Terror and Palpitation due to FrightAcctually Terror(驚) is different from Palpitation(悸). Terror(驚) is one of the seven emotions. But in this case, It refer to the Palpitation and the uneasiness of mind due to one's hearing a strange sound of seeing a strange. Tremulous Pulse can be appear. So Terror(驚) is caused by Exopathic Factors(外因) and belongs to Excess syndrome(實證). Palpitaion(悸) is the sensation of plamus, palpitation and unrest not because of being frightened. It is usurally caused by the deficiency of Ki(氣) and blood(血). So Deep, Thready and weak pulse can be appear. So Palpitaion(悸) is caused by Endopathic Factors and belongs to Deficiency Syndrome. In this Chapter, Terror and Palpitation due to Fright(驚悸) treat with the Kyeji-ke-jakyak-ka-chokchil-moryu-yongkol-kuyuk-tang(桂枝去芍藥加蜀漆牡蠣龍骨救逆湯) and Banha-mahwang-hwan(半夏麻黃丸). There are two type in Hemorrhagic disease(血證). One is bleeding(出血) and another is blood stasis(瘀血). The contents which relate with the Hemorrhagic disease(血證) are Hematemisis(吐血), Rhinorrhagia, Hemafecia(下血). In hemorrhage pathological mechanisms, there are two mechanisms. One is that Fire and Heat(火熱) pressure blood. Another is that cold and deficiency(虛寒) disable Ki(氣) from keeping blood flowing within vessels. Blood stasis(瘀血) can be called Extravasated Blood(惡血), Coagulated Blood, Blood retention(蓄血,積血), Dead Blood(死血) and Emaciation due to Blood disorder(乾血). It refer to a morbid state of unsmooth circulation and blood stagnancy often resulting from Ki(氣) stagnation, Ki(氣) deficiency and accumulation of pathogenic coldness. The symptom of Blood stasis are 'Fullness sensation in the chest, Lip Flaccidity, Cyonotic Tongue and Dryness of Mouth'. And the man who have Blood stasis, want to rinse his mouth with the water, but he can't drink the water because there isn't interior Heat of Excess Type. The symptom of Cyonotic Tongue(舌靑) had influence on diagnosing Blood stasis(瘀血) in offspring.

Comparative analysis of two methods of laser induced boron isotopes separation

  • K.A., Lyakhov;Lee, H.J.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.407-408
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    • 2011
  • Natural boron consists of two stable isotopes 10B and 11B with natural abundance of 18.8 atom percent of 10B and 81.2 atom percent of 11B. The thermal neutron absorption cross-section for 10B and 11B are 3837 barn and 0.005 barn respectively. 10B enriched specific compounds are used for control rods and as a reactor coolant additives. In this work 2 methods for boron enrichment were analysed: 1) Gas irradiation in static conditions. Dissociation occurs due to multiphoton absorption by specific isotopes in appropriately tuned laser field. IR shifted laser pulses are usually used in combination with increasing the laser intensity also improves selectivity up to some degree. In order to prevent recombination of dissociated molecules BCl3 is mixed with H2S 2) SILARC method. Advantages of this method: a) Gas cooling is helpful to split and shrink boron isotopes absorption bands. In order to achieve better selectivity BCl3 gas has to be substantially rarefied (~0.01%-5%) in mixture with carrier gas. b) Laser intensity is lower than in the first method. Some preliminary calculations of dissociation and recombination with carrier gas molecules energetics for both methods will be demonstrated Boron separation in SILARC method can be represented as multistage process: 1) Mixture of BCl3 with carrier gas is putted in reservoir 2) Gas overcooling due to expansion through Laval nozzle 3) IR multiphoton absorption by gas irradiated by specifically tuned laser field with subsequent gradual gas condensation in outlet chamber It is planned to develop software which includes these stages. This software will rely on the following available software based on quantum molecular dynamics in external quantized field: 1) WavePacket: Each particle is treated semiclassicaly based on Wigner transform method 2) Turbomole: It is based on local density methods like density of functional methods (DFT) and its improvement- coupled clusters approach (CC) to take into account quantum correlation. These models will be used to extract information concerning kinetic coefficients, and their dependence on applied external field. Information on radiative corrections to equation of state induced by laser field which take into account possible phase transition (or crossover?) can be also revealed. This mixed phase equation of state with quantum corrections will be further used in hydrodynamical simulations. Moreover results of these hydrodynamical simulations can be compared with results of CFD calculations. The first reasonable question to ask before starting the CFD simulations is whether turbulent effects are significant or not, and how to model turbulence? The questions of laser beam parameters and outlet chamber geometry which are most optimal to make all gas volume irradiated is also discussed. Relationship between enrichment factor and stagnation pressure and temperature based on experimental data is also reported.

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Effect of Non-Equilibrium Condensation on Force Coefficients in Transonic Airfoil Flow (천음속 에어포일 유동에서 비평형 응축이 Force Coefficients 에 미치는 영향)

  • Jeon, Heung Kyun;Choi, Seung Min;Kang, Hui Bo;Kwon, Young Doo;Kwon, Soon Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.12
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    • pp.1009-1015
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    • 2014
  • The present study investigated the effects of non-equilibrium condensation with the angle of attack on the coefficients of pressure, lift, and drag in the transonic 2-D flow of NACA0012 by numerical analysis of the total variation diminishing (TVD) scheme. At $T_0=298k$ and ${\alpha}=3^{\circ}$, the lift coefficients for $M_{\infty}=0.78$ and 0.81 decreased monotonically with increasing ${\Phi}_0$. In contrast, for $M_{\infty}$ corresponding to the Mach number of the force break, $C_L$ increased with ${\Phi}_0$. For ${\alpha}=3^{\circ}$ and ${\Phi}_0=0%$, $C_D$ increased markedly as $M_{\infty}$ increased. However, at ${\Phi}_0=60%$ and ${\alpha}=3^{\circ}$, which corresponded to the case of the condensation having a large influence, $C_D$ increased slightly as $M_{\infty}$ increased. The decrease in profile drag by non-equilibrium condensation grew as the angle of attack and stagnation relative humidity increased for the same free stream transonic Mach number. At ${\Phi}_0=0%$, the coefficient of the wave drag increased with the attack angle and free stream Mach number. When ${\Phi}_0$ > 50%, the coefficient of the wave drag decreased as ${\alpha}$ and $M_{\infty}$ increased. Lowering ${\Phi}_0$ and increasing $M_{\infty}$ increased the maximum Mach number.

A Numerical Study of Building Orientation Effects on Evacuation Standard in Case of Toxic Gas Leakage (독성 가스 누출 시 건물 방향이 대피 기준에 미치는 영향에 관한 수치 해석 연구)

  • Seungbum Jo
    • Journal of the Korean Institute of Gas
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    • v.27 no.4
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    • pp.12-18
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    • 2023
  • The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.