• 한국초전도ㆍ저온공학회논문지
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• 제18권3호
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• pp.30-34
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• 2016

An integral crank driven Stirling cryocooler is solidly based on concepts of direct IR detector mounting on the cryocooler's cold finger, and the integral construction of the cryocooler and Dewar envelope. Performance factors of the cryocooler depend on operating conditions of the cryocooler such as a cyclic mean pressure of the working fluid, a rotational speed of driving mechanism, a thermal environment, a targeted operation temperature and etc.. At given charging condition of helium gas, the cyclic mean pressure of helium gas in the cryocooler changes with temperatures of the cold end and the environment. In this study, effects of the cyclic mean pressure of helium gas on performances of the Stirling cryocooler were investigated by numerical analyses using the Sage software. The simulation model takes into account thermodynamic losses due to an inefficiency of regenerator, a pressure drop, a shuttle heat transfer and solid conductions. Simulations are performed for the performance variation according to the cyclic mean pressure induced by the temperature of the cold end and the environment. This paper presents P-V works in the compression and expansion space, cooling capacity, contribution of losses in the expansion space.

• 대한기계학회논문집B
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• 제20권8호
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• pp.2670-2680
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• 1996

Effeccs of porous wind fence on surface-pressure around 2-dimensional prism model of triangular cross-section were investigated experimentally. The pressure data were obtained at a Reynolds number based on the model height of Re=2.1*10$^{5}$ . Flow visualization also carried out to investigate the flow structure qualitatively. The mean velocity and turbulent intensity profiles measured at fence location were well fitted to the neutral atmospheric surface boundary layer over the open terrain. Various fences with different porosity and height were tested to investigate their effects on the surface pressure acting on a prism model at different locations. As the results, porous fence with porosity 40 ~ 50% is most effective for abating wind erosion. With decreasing porosity of the fence, pressure fluctuations on the model surface are increased. The mean pressure coefficients are decreased only when the fence height is greater than the model height. The effect of distance between wind fence and triangular prism was not significant, compared to that of the fence porosity and height.

• Journal of Korean Biological Nursing Science
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• 제18권4호
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• pp.280-287
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• 2016

Purpose: This study was to evaluate the effects of information on anxiety, blood pressure and pulse in cerebral angiography clients. Methods: The data were collected from June to November 2014. The participants were 42 (21 each for experimental and control group) patients who to received cerebral angiography. The information developed from researchers' materials for cerebral angiography was provided only to experimental group. Measured variables were anxiety, systolic and diastolic blood pressure, and pulse rate. Research tools for anxiety were Spielberger's state anxiety inventory, and 10 point visual analogue scale (VAS). Results: The difference in mean systolic blood pressure after intervention between the experimental group ($129{\pm}15.34$) and the control group ($141{\pm}17.70$) was statistically significant (t=-2.28, p=.028). The differences between the two groups in state anxiety, VAS anxiety, diastolic blood pressure, and pulse rate after intervention were not statistically significant (p>.05). Conclusion: The information using educational material was effective in to decreasing systolic blood pressure in patients who received cerebral angiography. Therefore this study material could be used as a nursing intervention for patients in cerebral angiography.

• Journal of Mechanical Science and Technology
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• 제14권2호
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• pp.236-250
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• 2000

Compression ignition direct injection diesel engines employed a high pressure injection system have been developed as a measure to improve a fuel efficiency and reduce harmful emissions. In order to understand the effects of the pressure variation, many experimental works have been done, however there are many difficulties to get data in engine condition. This work gives numerical results for the high pressure effects on spray characteristics in wide or limited space with near walls. The gas phase is modelled by Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled using the discrete droplet model approach in Lagrangian form and the drop behavior on a wall is calculated with a new droplet-wall interaction model based on the experiments observing individual drops. The droplet distributions, vapour fractions and gas flows are shown in various injection pressure cases. In free spray case which the injection spray has no wall impaction, the spray dispersion and vapour fraction increase and drop sizes decrease with increasing injection pressure. The same phenomena appears more clearly in wall impaction cases.

• 한국의류학회지
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• 제29권6호
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• pp.783-792
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• 2005

The purpose of this research is to develop appropriate Insole according to foot characteristics of female adults. This research concentrates on proving the effectiveness of Insole on resolving foot discomforts by analyzing the differences between the fitting and foot pressure before and after wearing Insole. Among 216 female testers of previous research, six testers wear selected and placed into six different groups classified according to foot discomforts and foot characteristics. After wearing Insole, the results indicates that the entire groups represented the improvement of fitting and the mitigation of foot discomfort. The results of foot pressure experiment shows that the maximum pressure of foot spreads out evenly after wearing Insole, which indicates the effectiveness of Insole. This efficacy works particularly well for foot testers of second and sixth group. The results indicate that group 6, which consist of the flat-footed and the old, have more noticeable effects derived from Insole, whereas group 3 and 5 do not, due to its constitution of people with fairly normal feet. Furthermore, it was evident that maximum pressure played a major role in proving the beneficial effects of Insole, one of which is to scatter the maximum pressure of heel away and lessen the foot pressure of plantar.

• Wind and Structures
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• 제5권1호
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• pp.25-48
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• 2002

Wind flow and pressure on the roof of the Texas Tech Experimental Building are studied along with the incident wind in an effort to understand the wind-structure interaction and the mechanisms of roof pressure generation. Two distinct flow phenomena, cornering vortices and separation bubble, are investigated. It is found for the cornering vortices that the incident wind angle that favors formation of strong vortices is bounded in a range of approximately 50 degrees symmetrical about the roof-corner bisector. Peak pressures on the roof corner are produced by wind gusts approaching at wind angles conducive to strong vortex formation. A simple analytical model is established to predict fluctuating pressure coefficients on the leading roof corner from the knowledge of the mean pressure coefficients and the incident wind. For the separation bubble situation, the mean structure of the separation bubble is established. The role of incident wind turbulence in pressure-generation mechanisms for the two flow phenomena is better understood.

• International journal of advanced smart convergence
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• 제7권3호
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• pp.44-60
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• 2018

This study is to identify the effects of hypertension management program at a community health center on the disease-related knowledge, self-efficacy, anthropometric measurements and blood pressure of a hypertensive patient in local community. This study is a quasi-experimental study using nonequivalence control group no-synchronized design in order to verify the effects of the hypertension management program at a community health center on the hypertension-related knowledge, self-efficacy, anthropometric measurements and blood pressure of a hypertensive patient in local community. The result indicated a significant difference between the experimental group and control group in the scores of hypertension-related knowledge (t=-4.25, p<.001), self-efficacy (t=-4.20, p<.001), systolic blood pressure (t=7.70, p<.001) and diastolic blood(t=5.91, p<.001), body weight(t=2.32, p=.026) and abdominal circumference(t=2.17, p=.036). The hypertensive patients' knowledge and self-efficacy were improved, and their weight and abdominal circumference as well as systolic blood pressure and diastolic blood pressure were reduced. Therefore, it was confirmed that multilateral approaches in terms of physical and psychosocial aspects only targeting hypertensive patients were required for managing hypertensive patients in local community.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.1-10
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• 2010

The present study is a fundamental approach to develop the measuring technology for minute fluctuating pressures on the three-dimensional blade surfaces of the fan which rotates with an arbitrary rotation-axis direction. In this situation, we are required to correct the centrifugal-force effect, the gravitational-force effect and the other leading-error effects for accurate measurements of the minute pressures. The working fluid is air. A pressure transducer rotating with an arbitrary attitude is closely sealed by a twofold shroud system. The rotational motion with an arbitrary attitude is produced by fixing the pressure transducer to the cantilever which is connected to a motor-driven disc of 500mm in diameter and 5mm in thickness. As a result, we have quantitatively determined main governing effects upon the non-effective component of the pressure-transducer signal.

• 한국농공학회논문집
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• 제54권5호
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• pp.49-55
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• 2012

In order to derive the efficient utilization of low pressure compressed air fogging system, cooling efficiencies with control types were analyzed through cooling experiments in tomato greenhouses. The control types were set up with temperature control, humidity control, temperature and humidity control, and time control. It showed that the cooling effects were 0.7 to $3.3^{\circ}C$ on average and maximum of 4.3 to $7.0^{\circ}C$, the humidification effects were 3.5 to 13.5 % on average and maximum of 14.3 to 24.4 %. Both the cooling and humidification effect were the highest in the time control method. The cooling efficiency of the air fogging system was not high with 8.3 to 27.3 % on average. However, the cooling efficiency of 24.6 to 27.3 % which appears from the time control is similar to the cooling efficiency of high pressure fogging system experimented in Japan. The air fogging system is operated by low pressure, but its efficiency is similar to high pressure. We think because it uses compressed air. From this point of view, we suggest that the air fogging system can get the cooling efficiency of similar levels to that of high pressure fogging system and it will have an advantage from clogging problem of nozzle etc.

• 대한기계학회논문집B
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• 제21권5호
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• pp.637-649
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• 1997

Effects of cone angle, pressure-hole orientation and Reynolds number on the five-hole probe calibration have been investigated for eight large-scale conical five-hole probes, which have either perpendicular pressure holes or forward-facing pressure holes for the cone angles of 45 deg, 60 deg, 75 deg and 90.deg. Pitch and yaw angles are changed from -40 deg to +40 deg with an interval of 5 deg, respectively, when the probe Reynolds numbers are 1.77*10$^{4}$, 3.53*10$^{4}$ and 7.06*10$^{4}$. The result shows that larger cone angle results in more sensitive changes in the calibration coefficients. In the case that the cone angle is 45 deg, the pitch-angle and yaw-angle coefficients of the five-hole probe with the perpendicular pressure holes show a very different trend compared with those of the five-hole probe with the forward-facing pressure holes. On the other hand, when the cone angle is more than 60 deg, each calibration coefficient is nearly independent of the pressure-hole orientation. Additionally, the effects of the Reynolds number on the calibration coefficients are also reported in detail.