• Tribology and Lubricants
• /
• v.17 no.3
• /
• pp.198-208
• /
• 2001

A Parametric study based on a computer analysis of the lubrication system of a four-cylinder gasoline engine is illustrated. Through the parametric study, the effects of various aeration levels on the change of oil flow rate and pressure are investigated. Also, at high oil temperature and low engine speed, the effect of oil aeration level on oil flow characteristics in lubrication system is investigated. The illustrated results may give to designers the guide lines of oil aeration level for the safe design of engine lubrication systems in terms of minimum pressure at crank oil bore.

• Journal of Biomedical Engineering Research
• /
• v.11 no.2
• /
• pp.203-208
• /
• 1990

A possible asymmetry in airway inertance was modeled based on previously reported radiographic visualization data of the airway wall fluctuation in intact dogs. Effects of asymmetric Inertance on mean lung volume during high frequency ventilation (HFV) were evaluated in terms of mean inertive pressure drop across the airways. It was found that a negligible inertlve pressure drop was expected ($<1{\;}cmH_20$) in normal subjects, while a sig- nificant rise in mean alveolar pressure compared to mean mouth pressure by approximately $3{\;}cmH_20$ was resulted for about 40% airway fluctuation representing bronchoconstriction state by Histamine induction. These results demonstrate that asymmetric Inertance could lead patients with airway diseases to a significant lung hyperinflation (LHI), and bronchodilation treatment is recommended prior to applying HFV to prevent those patients from a possible barotrauma.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.11a
• /
• pp.193-199
• /
• 1999

In the 3-Dimensional contact of the smooth spheres, the effects of friction on the contact area and the distribution of contact pressure was studied numerically. The contact area and pressure distribution was evaluated for the only normal load and for the case of a normal load in the presence of a tangential traction. To do this work, the technique of simple discretization using the load . displacement relationship for a uniformly distributed load of a rectangular patch was used.

• The Journal of Korean Medicine
• /
• v.18 no.1
• /
• pp.267-277
• /
• 1997

Experiments were performed to determine the effects of the Oyacksunkisan(烏藥順氣散) and Kamioyacksunkisan(加味烏藥順氣散) liquid extract on the hypertension and the pulse rate in Sprague-Dawley rat(SDR) and Spontaneous Hypertensive rats(SHR). The results were obtained as follows ; 1. Blood pressure was significantly decreased firstday and 11th day after administration of Oyacksunkisan extract and pretreatment of phentolamine. 2. Blood pressure and pulse rate were regulated first day after administration of Kamioyacksunkisan and blood pressure was significantly decreased after pretreatment of clonidine and phentolamine. 3. Oyacksunkisan and Kamioyacksunkisan didn't show any significant changes of blood pressure and pulse rate after pretreatment of prdpranolol, hydralazine and verapamil From the above result, it was concluded that Oyacksunkisan(烏藥順氣散) and Kamioyacksunkisan(加味烏藥順氣散) could be applied effectively to the hypertension.

• Nuclear Engineering and Technology
• /
• v.36 no.4
• /
• pp.285-294
• /
• 2004

Pressure wave propagation in the discharge piping with a sparger submerged in a water pool, following the opening of a safety relief valve, is analyzed. To predict the pressure transient behavior, a RELAP5/MOD3 code is used. The applicability of the RELAP5 code and the adequacy of the present modeling scheme are confirmed by simulating the applicable experiment on a water hammer with voiding. As a base case, the modeling scheme was used to calculate the wave propagation inside a vertical pipe with sparger holes and submerged within a water pool. In addition, the effects on wave propagation of geometric factors, such as the loss coefficient, the pipe configuration, and the subdivision of sparger pipe, are investigated. The effects of inflow conditions, such as water slug inflow and the slow opening of a safety relief valve are also examined.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.05a
• /
• pp.139-143
• /
• 2001

Ring-stiffened cylinders are widely used as the pressure hull of submarines and underwater vehicles. For large ring-stiffened cylinders cylindrical shells are fbricated by cold rolling of flat plates and then welding of curved shells. After forming cylinders ring-stiffeners are welded on th the cylinders. Due to these cold roiling and welding initial shape imperfections and residual stresses exists in fabricated ring-stiffened cylinders. It is well known that the initial shape and material imperfections affect the ultimate strength of ring-stiffened cylinders significantly. In this paper previous researches on the effects of initial shape imperfections and residual stresses are briefly reviewed Recently a numerical analysis computer program was developed to predict the ultimate strength of ring-stiffened cylinders subjected to hydrostatic pressure, which is based on the Dynamic Relaxation technique. This program was employed to numerically investigate those effects. The numerical predictions were substantiated with relevant experimental results.

• Journal of the Semiconductor & Display Technology
• /
• v.12 no.2
• /
• pp.93-98
• /
• 2013

Nanoimprint lithography (NIL) is a next generation technology for fabrication of micrometer and nanometer scale patterns. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. To successfully imprint a nanosized pattern with the thermal NIL, the process conditions such as temperature and pressure should be appropriately selected. This starts with a clear understanding of polymer material behavior during the thermal NIL process. In this paper, a filling process of the polymer resist into nanometer scale cavities during the thermal NIL at the temperature range, where the polymer resist shows the viscoelastic behaviors with consideration of stress relaxation effect of the polymer. In the simulation, the filling process and the residual layer formation are numerically investigated. And the effects of pressure and temperature on NIL process, specially the residual layer formation are discussed.

• The Journal of Korean Physical Therapy
• /
• v.26 no.6
• /
• pp.391-397
• /
• 2014

Purpose: The aim of this study was to investigate the effects of manual lymph drainage (MLD) on the activity of sympathetic nervous system, anxiety, pain and pressure pain threshold in subjects with psychological stress. Methods: Twenty-nine subjects with psychological stress were randomly assigned to experimental (MLD) and control (rest) groups. This study was performed as a controlled, randomized study using spectral analysis of electrocardiographic (ECG) activities, the State-Trait Anxiety Inventory (STAI), Visual Analogue Scale (VAS) and Pressure Pain Threshold (PPT). Results: Heart rate variability differed significantly between the experimental and control groups (p<0.05). Anxiety and pain showed positive change in both group but it were not showed statically differences. The pressure pain threshold in the upper trapezius muscle was increased in the experimental group (p<0.05). Conclusion: These findings indicate that the application of MLD was effective in reducing the activity of the sympathetic nervous system, anxiety, pain, and increasing the PPT.

• Computers and Concrete
• /
• v.8 no.4
• /
• pp.425-443
• /
• 2011

Most previous studies have generally overlooked the contribution of thermal stresses generated within the concrete mass when subjected to microwave heating and reported on pore-pressure as being the dominant cause of surface spalling. Also, the variation in electromagnetic properties of concrete and its effects on the microwave heating process have not been studied in detail. In this paper, finite element modeling is used to examine the simultaneous development of compressive thermal stresses and pore-pressure arising from the microwave heating of concrete. A modified Lambert's Law formulation is proposed to estimate the microwave power dissipation in the concrete mass. Moreover, the effects of frequency and concrete water content on the concrete heating rate and pattern are investigated. Results show high compressive stresses being generated especially in concrete with a high water content when heated by microwaves of higher frequencies. The results also reveal that the water content of concrete plays a crucial role in the microwave heating process.

• Journal of Integrative Natural Science
• /
• v.12 no.3
• /
• pp.74-77
• /
• 2019

The purpose of this study is to explore the effects of Chamaecyparis obtusa essential oil on the activity of autonomic nervous system. Heart rate variability (HRV), as an indicator of autonomic nervous system activity and blood pressure were measured before and after inhalation of Chamaecyparis obtusa essential oil. The systolic blood pressure was decreased by inhalation of Chamaecyparis obtusa essential oil (p<0.05). The diastolic blood pressure was not changed significantly by Chamaecyparis obtusa. High frequency (HF) power level was not changed but High frequency/Low frequency (HF/LF) ratio was decreased by Chamaecyparis obtusa essential oil (p<0.05), meaning that parasympathetic nervous system activity was not affected but sympathetic nervous system activity was decreased. These results indicate that Chamaecyparis obtusa essential oil has a modulatory effect on the autonomic nervous system activity.