• Title/Summary/Keyword: pressure effects

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Experimental study of wind-induced pressures on tall buildings of different shapes

  • Nagar, Suresh K;Raj, Ritu;Dev, Nirendra
    • Wind and Structures
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    • v.31 no.5
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    • pp.431-443
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    • 2020
  • The modern tall buildings are often constructed as an unconventional plan and as twin buildings. Wind load on the tall building is significantly influenced by the presence of another building in the near vicinity. So, it is imperative to study wind forces on an unconventional plan shaped tall building. Mean wind pressure coefficients of a square and 'H' plan shape tall buildings are investigated using wind tunnel experiments. The experiments were carried out for various wind directions from 00 to 900 at an interval of 300 and various locations of the identical interfering building. The experimental results are presented at the windward face from the viewpoint of effects on cladding design. To quantify the interference effects, interference factors (I.F) are calculated. Mean pressure coefficients of both models are compared for isolated and interference conditions. The results show that pressure reduces with an increase in wind angle till 600 wind direction. The interfering building at full blockage interference condition generates more suction than the other two conditions. The interference factor for both models is less than unity. H-plan building model is subjected to a higher pressure than the square model.

Effects of Moxibustion on Physiological Indices and Autonomic Nervous Symptoms in Adults with Prehypertension (뜸요법이 전고혈압 성인의 생리적 지수와 자율신경계 증상에 미치는 효과)

  • Cho, Soon-Hee
    • Journal of Korean Academy of Nursing
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    • v.40 no.5
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    • pp.686-694
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    • 2010
  • Purpose: This study was done to examine the effects of moxibustion on physiological indices, such as 24-hr blood pressure, pulse pressure, and pulse rate, and autonomic nervous symptoms among adults with prehypertension. Methods: Participants were adults whose systolic and diastolic blood pressures were in the prehypertension stage and were not under treatment for the condition. Both experimental and control group consisted of 13 participants who were taking classes on acupuncture and moxibustion at a private institute. The experimental group received moxibustion once a day for 15 min, at least 5 days a week for 8 weeks. The results were analyzed using $x^2$-test, t-test, Fisher's exact test, Wilcoxon rank sum test and repeated measures ANOVA with the SAS program. Bonferroni correction method was adopted for multiple comparisons. Results: No significant change was observed in the 24-hr systolic and diastolic blood pressure between the two groups. Differences in the 24-hr pulse pressure and pulse rate were also not significant. However, significant decreases in headache, symptoms of flushing and fatigue were observed in the experimental group. Conclusion: The results suggest that moxibustion contributes to alleviating symptoms such as headache, flushing and fatigue associated with the autonomic nervous system among adults with prehypertension.

Effects of McKenzie Cervical Exercise Program on Cervical Pressure Pain and Balance in Industrial Workers (맥캔지 경부 운동프로그램이 산업체 근로자의 경부압통과 균형에 미치는 영향)

  • Lee, Hyongsoo;Kim, Yoonhwan
    • Journal of The Korean Society of Integrative Medicine
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    • v.6 no.2
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    • pp.107-115
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    • 2018
  • Purpose : The purpose of this study was to determine the effects of the McKenzie cervical exercise program on cervical pressure pain and balance in industrial workers. Method : The subjects, who consisted of 26 industrial workers, were randomly divided into two groups. The control group (n=13) went about their daily living routines. The other group (n=13) used the McKenzie cervical exercise program for 6 weeks (2 to 3 times/day). Pressure threshold and balance ability tests were completed before and after the experiment. The balance test was performed both with the eyes open and closed in a standing position. Result : There were significant improvements in the pressure threshold and balance ability test for the McKenzie cervical exercise program group (p<.05), while the control group showed no significant changes (p>.05). Conclusion : The above results revealed that the McKenzie cervical exercise program is effective in improving balance and cervical pressure pain.

A Study on the Collapse Strength Characteristics of Ship Bottom Plating Subject to Slamming Induced Impact Lateral Pressure Loads (선저슬래밍 충격횡압력을 받는 선체 판부재의 붕괴강도 특성에 관한 연구)

  • Jeom-Kee Park;Jang-Yang Chung;Young-Min Paik
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.2
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    • pp.77-93
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    • 1999
  • The twin aims of the paper are to investigate the collapse strength characteristics of ship plating subject to impact pressure loads and to develop a simple structural design formula considering impact load effects. The general purpose nonlinear finite element program STARDYNE together with existing experimental results is used to investigate the collapse behavior of plating under impact pressure loads. The rigid plastic theory taking into account large deflection effects is applied to the development of the design formulation. In the theoretical method, the collapse strength formulation for plating subject to hydrostatic pressure is first derived using the rigid plastic theory. By including the strain rate erects in the formulation it can be applied to impact pressure problems. As illustrative examples, the collapse behavior of steel unstiffened plates and aluminum alloy stiffened panels subject to impact pressure loads is analyzed.

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Effects of a Self-regulation Program on Blood Pressure Control and Self-Care in Patient with Essential Hypertension (자기조절프로그램이 고혈압환자의 혈압 및 자가간호행위에 미치는 효과)

  • Choo, Hyang Im;Kim, Gwang Suk
    • Journal of Korean Academy of Rural Health Nursing
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    • v.6 no.1
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    • pp.33-43
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    • 2011
  • Purpose: This study was done to verify the effects of a self-regulation program for management of hypertension. Method: Thirty patients with hypertension registered in a community health center were selected as the experiment group, and control group were patients in another community health center, matched for age and gender. The self-regulation program included daily blood pressure checks, periodic counseling, and health education. A self-check digital device with instructions was provided for self-monitoring of blood pressure, and the participants were interviewed before they took part in the program. Results: The first hypothesis was supported: There will be a greater reduction in both systolic and diastolic blood pressure for patients with hypertension who participate in the self-regulation program compared to patients in the control group. The second hypothesis was also supported: Patients with hypertension who participate in the self-regulation program will perform self-care activities better than those in the control group. Conclusion: The findings indicate that a self-regulation program reduces systolic and diastolic blood pressure and improves self-care in patients with hypertension. It is recommended that this self-regulation program be used in community health clinics for management of hypertension and prevention of complications.

Pressure Effects on the Hg-doped Heavy-fermion Superconductor $CeRhIn_5$ (Hg을 도핑한 무거운 페르미온 초전도체 $CeRhIn_5$의 압력에 따른 변화)

  • Seo, S.;Ju, S.;Bauer, E.D.;Thompson, J.D.;Park, T.
    • Progress in Superconductivity
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    • v.14 no.1
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    • pp.17-23
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    • 2012
  • The heavy-fermion compound $CeRhIn_5$ is a prototypical antiferromagnet where Ce 4f moments align antiferromagnetically below 3.8 K. When doped with Hg, the antiferromagnetic transition $T_N$ initially decreases, becomes flat, and increases again with further increasing Hg concentration. Here we report pressure effects on the electrical resistivity of a 0.45 % Hg-doped $CeRhIn_5$, where $T_N$ is 3.4 K and the magnetic structure is same as that of the undoped compound with Q=(1/2, 1/2, 0.298). With increasing pressure, $T_N$ is suppressed and a superconducting state emerges. The temperature dependence of the electrical resistivity near an optimal pressure shows a power-law behavior that deviates from a $T^2$ dependence, indicating presence of abundant quantum fluctuations near the optimal pressure.

Experimental Study of Reynolds Number Effects on Heat/Mass Transfer and Pressure Drop Characteristics in a Rotating Smooth Duct (매끈한 벽면을 가진 회전덕트 내 레이놀즈 수에 따른 열/물질전달 및 압력강하 특성 연구)

  • Kim, Kyung-Min;Park, Suk-Hwan;Lee, Dong-Hyun;Cho, Hyung-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.11
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    • pp.888-895
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    • 2006
  • The present study has been conducted to investigate the effects of Reynolds number on heat/mass transfer and pressure drop characteristics in a rotating smooth two-pass duct. For stationary cases, the heat/mass transfer and pressure drop Is decreased on turning region of both leading and trailing surfaces as Reynolds number increases. For rotating cases, increment of Reynolds number affects differently the heat/mass transfer and pressure drop on the leading and trailing surfaces. In the first pass, for example, the heat/mass transfer on the leading surface is greatly increased, though the heat/mass transfer on the trailing surface is almost the same. The reason is that effect of the main flow is more dominant than effect of secondary flow. In particular, it gave decrement of the heat/mass transfer and the pressure drop at turning region and upstream region of second pass for both non-rotating and rotating cases.

Effects of High Pressure Homogenization on Physicochemical Properties of Starch Films (고압균질처리가 전분필름의 물성에 미치는 영향)

  • Kang, Eun-Jung;Lee, Jae-Kwon
    • Food Engineering Progress
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    • v.15 no.1
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    • pp.70-74
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    • 2011
  • The effects of high pressure homogenization (microfluidization) on physicochemical properties of normal maize and oxidized maize starch film were studied. The molecular dispersibility of amlyose and amylopectin and the disintegration of granular structure had a marked effect on the physicochemical properties of starch films. The high pressure homogenized starch films showed increased solubility and transmittance due to the absence of gelatinized starch granules. The tensile strength of starch film increased significantly with decreasing oxygen permeability after high pressure homogenization, indicating that starch molecules were more uniformly and fully dispersed during the film formation. As a result, a clear starch film with improved mechanical properties was obtained after high pressure homogenization due to the increased interactions between the uniformly dispersed starch molecules.

Effects of pressure biofeedback application location for subjects with lumbar instability on pelvic rotation and hip joint abductor muscle activity during the Clam exercise.

  • Choi, Yonggil;Lee, Sangyeol
    • Physical Therapy Rehabilitation Science
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    • v.10 no.2
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    • pp.90-97
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    • 2021
  • Objective: The purpose of this study was to find out how the back instability during clam exercise (CE) causes changes in pelvic rotation and hip joint abductor muscle activity, and to find out the effects with different methods of application of pressure biofeedback. Design: Comparative study using repeated measures. Methods: Each subjects performed the clam exercise (CE) without pressure biofeedback, the clam exercise with pressure biofeedback applied to the back (CE-PBU to back), and the clam exercise with pressure biofeedback applied to the side (CE-PBU to side). The amount of pelvic rotation was measured using myomotion. And the muscle activity of the muscle gluteus medius and the tensor fasciae latae was measured using EMG device. One-way repeated measures ANOVA followed by the Bonferroni post test were used to compare the EMG activity in each muscle and pelvic rotation angle during the CE, CE-PBU to back, CE-PBU to side. Results: The amounts of pelvic rotation was the lowest in CE-PBU to back (p< 0.05) and the ratio of muscle activity of the muscle gluteus / tensor fasciae latae was the highest in CE-PBU to back (p< 0.05). Conclusions: It is thought that, in order to stabilize the waist-pelvis and increase hip joint muscle strength in subjects with back instability, applying clam exercise with pressure biofeedback applied to the lower back is effective in improving waist-pelvic movements and selectively strengthening the muscle gluteus medius.

Effects of Pleating Parameters on Characteristics of Cylindrical Cartridge Air Filters (원통형 카트리지 에어 필터(cartridge Air filters)의 절곡 변수에 따른 집진 성능 변화)

  • Park, H.S.;Park, S.J.;Kim,, S.D.;Choi, H.K.;Lim, J.H.;Park, Y.O.
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.154-157
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    • 2001
  • The effects of pleating parameters on the performance of cylindrical cartridge air filters was experimentally studied. The tested filters are 150 mm in outer diameter and 700 mm in length. As the pleat count increases, the pressure drop across a cartridge filter is decreased for a constant pleat depth and flow rate. This is due to the increased filtration area which brings out less pressure loss of the filter. However, in the case of the filters having the pleat depth of 40 mm, the inner diameter of the cartridges is so small that the pressure loss is greatly increased.

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