• Title/Summary/Keyword: pressure relation

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The effect of involuntary muscle contraction due to forward head position in pressure pain threshold of pericranial muscle (두부전방자세에 의한 불수의적 근수축이 두개주위근의 압력 통증 역치에 미치는 영향)

  • Chae Yun-Won;Kim Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.12 no.3
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    • pp.339-347
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    • 2000
  • To elucidate pressure pain threshold of pericranial muscle due to involuntary. the effect of 30 min or forward head position(FHP) was studied in 20 patients with episodic tension-type headache and in 20 control without headache. Pressure pain thresholds were recorded before and after the FHP. and evaluated by pressure algometry. Thresholds increased in the patients and control after FHP. Relation between thresholds in patients anf control before FHP were not significant differences, but thresholds increased in patients after FHP. So, involutary muscle contraction due to FHP may be effect pressure pain threshold or pericranial muscle.

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A Study on the Characteristics of an Evaporating Diesel Spary Using LIEF Technique (LIEF법을 이용한 증발 디젤 분무의 특성에 관한 연구)

  • Kim, Y.R.;Kim, M.S.;Cho, H.;Min, K.D.
    • Journal of ILASS-Korea
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    • v.7 no.3
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    • pp.18-23
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    • 2002
  • An evaporating diesel spray of a common rail lnjector was visualized by LIEF technique. This technique makes it possible to separate the vapor and liquid phase images. The experiment was conducted in a constant volume vessel to make a high temperature and high pressure condition. Three images(vapor and liquid phase images from LIEF and a liquid phase image from Mie scattering) were taken simultaneously in one spray event. The major experimental parameters are the injection pressure and the ambient gas pressure. Also, a relative SMD distribution in a liquid phase was obtained by the ratio of the intensities of the fluorescence and the Mie scattering. The results show that the injection pressure and the ambient gas pressure have a close relation with the spray development and air-fuel muting process.

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Development of Evaluation and Prediction Model for Concrete High Speed Pumping (고강도콘크리트의 고속펌핑을 위한 압송성평가 및 예측모델에 관한 연구)

  • Kim, Hyung-Rae;Cho, Ho-kyoo;Jeong, Woong-Taek
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.05a
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    • pp.201-203
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    • 2012
  • The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for the evaluation of concrete pumping performance for high speed construction of super-tall building. So, this study focuses on quantitative evaluation of concrete fluid characteristics and surface friction resistance under the change of concrete mix proportion and pumping condition. In this study, we measured the rheology of concrete and pipe pressure and surface friction characteristics when pumping. And, relations between the rheology characteristics of concrete and pumping performance was investigated by experiment. As the result of the experiment, high regression between the surface friction and pressure gradient was confirmed. And, prediction model to evaluate the friction resistance coefficient and pipe pressure reduction coefficient was suggested.

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The Characteristics in Obesity Classification Group of College Student by Analyzing Their BMI and Blood Test and the Association between Factors Contributing to Obesity and Obesity according to BMI (대학생 체질량지수와 혈액검사결과 상 비만 분류군간 특성 및 비만 연관 요인 분석에 대한 연구)

  • Park, Jung-Sik;Lee, Jung-Jae;Oh, Hyun-Sook;Lim, Hyung-Ho
    • Journal of Korean Medicine Rehabilitation
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    • v.24 no.4
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    • pp.61-70
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    • 2014
  • Objectives The purpose of this study was to investigate the characteristics in obesity classification group of college students having health checkup by analyzing their BMI and blood test and determine the association between factors contributing to obesity and obesity according to BMI. Methods A group of 2992 test subjects took their medical examination and their body composition, height, weight, blood pressure were measured and blood test was done. With these results we diagnosed obesity, and analysed relationship between obesity and cholesterol, triglyceride, LDL (low density lipoprotein)-cholesterol, HDL (high density lipoprotein)-cholesterol, liver function, renal function and blood pressure. Results 1. Overweight individuals showed high total cholesterol, LDL-cholesterol, triglyceride, GOT (glutamic oxalacetic transaminase), GPT (glutamic pyruvate transaminase), Urea-nitrogen, Creatinine and low HDL-cholesterol. 2. BMI showed a significant association with other factors. BMI has a negative correlation with sex and HDL-cholesterol. BMI had positive correlations with other factors. 3. There was no relation between BMI and sex. Those six factors, liver function, cholesterol, blood pressure, kidney function, neutral fat, and blood sugar were related to BMI. Conclusions There was a significant relation between college students' BMI and their liver function, cholesterol, blood pressure, kidney function, neutral fat, and blood sugar. The diseases related to liver function, cholesterol, blood pressure, kidney function, neutral fat, and blood sugar were clearly associated with obesity.

New techniques for estimating the shut-in pressure in hydro-fracturing pressure-time curves

  • Choi Sung O.
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.272-280
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    • 2003
  • A definite shut-in pressure in hydraulic fracturing techniques is needed for obtaining the correct information on the in-situ stress regimes in rock masses. The relation between the behaviour of hydraulically induced fractures and the condition of remote stress is considered to be major reasons of an ambiguous shut-in pressure in hydraulic fracturing pressure-time history curves. This paper describes the results of a series of numerical analyses carried out using UDEC(Universal Distinct Element Code, Itasca), which is based on the discrete element method, to compare several methods for determining the shut-in pressure during hydraulic fracturing. The fully coupling of hydraulic and mechanical analysis was applied, and the effects of four different discontinuity geometries in numerical modelling have been investigated for this purpose. The effects of different remote stress regimes and different physical properties on hydraulic fracture propagation have been also analyzed. Several methods for obtaining shut-in pressure from the ambiguous shut-in curves have been applied to all the numerical models. The graphical intersection methods, such as (P vs. t) method, (P vs. log(t)) method, (log(P) vs. log(t)) method, give smaller values of the shut-in pressure than the statistical method, (dP/dt vs. P). Care should be taken in selecting a method for shut-in pressure, because there can be existed a stress anomaly around the wellbore and fracturing from the wellbore by a constant flow rate may have a more complicate mechanism.

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The Study on the Physicochemical Properties of Fluid under High Pressure (Ⅱ). The Effect of Pressure and Temperature on the Hexamethyl Benzene-Iodine Charge Transfer Complex in n-Hexane

  • Kwun Oh Cheun;Kim Jeong Rim
    • Bulletin of the Korean Chemical Society
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    • v.6 no.4
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    • pp.186-191
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    • 1985
  • The effect of pressure and temperature on the stabilities of the charge transfer complexes of hexamethyl benzene with iodine in n-hexane has been investigated by UV-spectrophotometric measurements. In this experiment the absorption spectra of mixed solutions of hexamethyl benzene and iodine in n-hexane were measured at 25, 40 and $60^{\circ}C$ under 1,200, 600, 1200 and 1600 bar. The equilibrium constant of the complex formation was increased with pressure while being decreased with temperature raising. Changes of volume, enthalpy, free energy and entropy for the formation of the complexes were obtained from the equilibrium constants. The red shift at higher pressure, the blue shift at higher temperature and the relation between pressure and oscillator strength were discussed by means of thermodynamic functions. In comparison with the results in the previous studies, it can be seen that the pressure dependence of oscillator strength has a extremum behavior in durene as the variation of ${\Delta}H$ or ${\Delta}S$ with the number of methyl groups of polymethyl benzene near atmospheric pressure in the previous study. The shift or deformation of the potential in the ground state and in the excited state of the complexes formed between polymethyl benzene and iodine was considered from the correlation between the differences of the electron transfer energies and the differences of free energies of the complex formation for the pressure variation.

A Study on the Relation between Cell morphology and Saturation condition in Gas-pellets MCPs (가스-펠릿 초미세 발포 사출 플라스틱 특성 연구)

  • Cha S. W.;Seo Jung-hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.12 s.177
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    • pp.87-92
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    • 2005
  • In microcellular injection molding, gas supply system is needed. But, that device is very expensive to attach to the injection molding machines. So, new method is needed and gas-pellets MCPs is one of the solutions. In gas-pellets MCPs, there will be strange characteristics. In this paper, some characteristics are described on the view point of saturation pressure and saturation time.

A Study on Mechanism of Hydrofracturing in Gelled Sandy Ground (약액으로 고결된 모래 지반의 수압파쇄에 관한 연구)

  • Chun, Byung Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.4
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    • pp.133-140
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    • 1990
  • Th. mechanism of hydraulic fracturing in sandy soil is elucidated by investigating the relation among the hydrofracturing pressure($P{_f}^{\prime}$), the confinning pressure(${\sigma}_3^{\prime}$), the tensile strength of gelled sand(${\sigma}_t$), and the permeability of sand(k) through many injection tests on several kind of sand.

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Note on Nonlinearity of Combustion Instability (연소 불안정 현상의 비선형적 특성 고찰)

  • 서성현
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.240-243
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    • 2003
  • Combustion instability phenomena have been observed in various different combustion systems. For each specific combustion system, pressure fluctuations measured during high frequency combustion instability presented many different characteristics. High frequency instability occurring in a lean premixed gas turbine combustor mar be dominantly affected by a nonlinear relation between pressure oscillations and heat release rate fluctuations, and gas dynamics plays a crucial role in determining an amplitude of a limit cycle for a liquid rocket thrust chamber. Combustion instability phenomena manifest their inherent nonlinear characteristics. One is a limit cycle and the other bifurcation described by nonlinear time series analysis.

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Comparative Evaluation of Clothing Pressure and Subjective Sensation Exerted by Foundation (파운데이션 착용으로 인한 의복압과 주관적 감각의 비교 평가)

  • Jeong, Jeong-Rim;Kim, Hee-Eun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.11 s.158
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    • pp.1531-1537
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    • 2006
  • This study was conducted to investigate the relation between clothing pressure and subjective sensation exerted by foundation. Nineteen females volunteered as subjects. Experimental foundations were brassiere with 70B, 70C, 75B and 75C size which were widely distributed in pilot test and two types of girdle of which size were 64, 70 and 76. Clothing pressure with an air pack system and subjective sensation were measured at 5 points in brassiere and 7 points in the girdle. As the result of this study, brassiere's band and girdle's waist line, of which clothing pressure are high, is needed to improve. Generally the more pressure makes the more tightness, however, in some regions more or less pressure can give comfort. The tightness rating may not only related to clothing pressure, but also related to factors such as body size, body fat, resilience of muscle and bone structure. Other subjective sensation such as tactile feeling, hot/wet feeling, etc. in addition to the study with consideration of these factors could be used in future research to evaluate the effectiveness of foundation.