• 대한중풍순환신경학회지
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• 제20권1호
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• pp.65-74
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• 2019

■ Objectives The purpose of this case study is to report the effectiveness of Korean medicine and pharmacopuncture in the treatment of pressure ulcer. ■ Methods The patient with pressure ulcer was treated with herbal medicine, Hwangryunhaedoktang pharmacopuncture, acu-moxi treatment. We started herbal medicine mainly Taklisodok-um for pressure ulcer, but changed to Paljung-san due to urinary tract infection on Day 67. During the daily dressing, we inject pharmacopuncture solution subcutaneous ulcer area and spray solution on the cavity of right pressure ulcer. The severity of pressure ulcer was assessed using[NPUAP] pressure ulcer stage, healing rate of pressure ulcer and depth of right side ulcer cavity on Day1, Day15, Day40, Day73, Day95. ■ Results After treatment, the total size of the pressure ulcer was reduced from 90(10*9) to 56(8*7)cm², healing rate of pressure ulcer increased to 37.8%, depth of pressure ulcer was reduced from 3.5 to 2cm. Though NPUAP stage(Gr 4) was not changed, size and color of pressure ulcer definitely improved compared to Day1. ■ Conclusion This study suggested taht Korean medical treatment could be effective option for treating grade 4 pressure ulcer.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.86-94
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• 2015

A series of injection and drainage test were conducted on an circular acrylic tube to investigate the pressure generated by the accumulated fill materials inside a circular acrylic tube structure. The acrylic tube was filled by means of gravity filling with a slurry material having an average water content of 700%. The water head during the filling process was 1.8m and the bottom pressure during initial filling was 20.18kPa. The recorded stress at the sides of the acrylic tube was 17.89kPa during the filling process and was reduced to 13.58kPa during the leaving process. Continuous drainage of the acrylic tube has greatly influenced the stresses around the tube structure. As the water is gradually allowed to overflow, the generated pressure at the topmost pressure sensor of the tube was reduced further to 2.17kPa. Eventually, the initially liquid state slurry material transforms into plastic state after water has dissipated and substantial soil particles are deposited in the acrylic tube. The final water content of the deposited silt inside the acrylic tube after the test was 42%. It was found that the state of stresses(geo-static earth pressures) in the acrylic tube was anisotropic rather than isotropic.

• 대한기계학회논문집B
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• 제23권1호
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• pp.140-148
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• 1999

Experiments on flame spread in an one-dimensional droplet array up to supercritical pressures of fuel droplet have been conducted In normal gravity and microgravity. Evaporating process around unburnt droplet is observed through high-speed Schlieren and direct visualizations in detail, and flame spread rate is measured using high speed chemiluminescence images of OH radical. Flame spread behaviors are categorized into three: flame spread is continuous at low pressures and is regularly intermittent up to the critical pressure of fuel. flame spread is irregularly intermittent and zig-zag at supercritical pressures of fuel. At atmospheric pressure, the limit droplet spacing and the droplet spacing of maximum flame spread rate in microgravity are larger than those in normal gravity. In microgravity, the flame spread rate with the increase of ambient pressure decreases initially, takes a minimum, and then decreases after taking maximum. This is so because the flame spread time is determined by competing effects between the increased transfer time of thermal boundary layer due to reduced flame diameter and the reduced ignition delay time in terms of the increase of ambient pressure. Consequently, it is found that flame spread behaviors in microgravity are considerably different from those in normal gravity due to the absence of natural convection.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.9-16
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• 2013

The comparisons of performance characteristics between the super-mirror face grinding machine using variable air pressure developed in this laboratory to grind precisely the sliding face of a surface hardened workpiece with thermal spray and the conventional one are investigated by measuring the surface roughness and hardness for a SCM440. To process variously workpiece according to shape, size and materials, the rotating and contacting forces of the developed grinding machine can be changed by air pressure. The surface roughness of processed workpiece can be also attained to state of mirror face by grinding precisely the sliding face with changing the rotating speed of diamond wheel. It is possible to be attached to the various machine tools because the super-mirror face grinding machine using variable air pressure is a small size. The grinding efficiency is elevated because it can be worked by two or more grinding machines attached to concurrently a machine tool for the large workpiece. In this study, results show that the cusp height of the super-mirror face grinding machine for the particle size of 100 and $1500No./mm^2$ is lower than that of the conventional one because the vibration is reduced by rotating very fast the diamond wheel with a pressed air and it can be processed by rotating the diamond wheel with a constantly varied air pressure perpendicular to workpiece surface, and that the workpiece in the super-mirror face grinding machine for the particle size of $3000No./mm^2$ can be processed to state of mirror face that is rarely seen by the cusp height. It is also found that the surface hardness of both the conventional and the super-mirror face grinding machines are increased as the particle size of diamond wheel is reduced, and the surface hardness of the super-mirror face grinding machine is HRC 1.1 ~ 1.8 higher than that of the conventional one.

• 한국식품조리과학회지
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• 제24권2호
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• pp.188-197
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• 2008

This study was carried out to determine the optimal cooking conditions for various rice cultivars (Ilpoom, Saechucheong, Sindongjin, and Sura-top rice) using trial preparations with different soaking times (0, 30, and l20min) and cooking equipment (electric pressure cookers, electric cookers, gas pressure cookers, iron pots, and stone pots). In adddition, the texture and sensory characteristics of the rice prepared with the electric pressure cookers, gas pressure cookers, and stone pots were analyed. The results showed that the moisture, amylose and physicochemical compositions of the four rice varieties were similar. According to RVA, the Sura, cultivar had generally high viscosity, and the Ilpoom, cultivar presented the highest hot and peak viscosities. Saechucung had the highest initial gelatinizing temperature and Sindongjin showed the greatest setback. The optimal amounts of added water as well as heating conditons were dependent on the rice varieties, soaking times, and cooking equipment. A longer soaking time reduced the hardness of the cooked rice, amount of added water, and the heating time. The pressure cooking equipment provided the best cooked rice texture, reduced the affect of the soaking time, and decreased the heating time. In general, all the variaties of cooked rice had high overall acceptability, which tended to increase when the rice was soaked for 30min prior to cooking, had a 1.2-fold amount of water to rice added, and was cooked in the pressure equipment.

• Wind and Structures
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• 제35권4호
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• pp.269-285
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• 2022

The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in C_Pmax, C_Pmin, and ΔC_P, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1122-1127
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• 2004

an isolated droplet combustion exposed to pressure perturbations in stagnant gaseous environment is numerically conducted. Governing equations are solved for flow parameters at gas and liquid phases separately and thermodynamic parameters at the interfacial boundary are matched for problem closure. For high-pressure effects, vapor-liquid interfacial thermodynamics is rigorously treated. A series of parametric calculations in terms of mean pressure level and wave frequencies are carried out employing a n-pentane droplet in stagnant gaseous air. Results show that the operating pressure and driving frequency have an important role in determining the amplitude and phase lag of a combustion response. Mass evaporation rate responding to pressure waves is amplified with increase in pressure due to substantial reduction in latent heat of vaporization. Phase difference between pressure and evaporation rate decreases due to the reduced thermal inertia at high pressure. In addition to this, augmentation of perturbation frequency also enhances amplification of vaporization rate because the time period for the pressure oscillation is much smaller than the liquid thermal inertia time. The phase of evaporation rate shifts backward due to the elevated thermal inertia at high acoustic frequency.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.709-714
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• 2000

A splitting method for the direct numerical simulation of solid-liquid mixtures is presented, where a symmetric pressure equation is newly proposed. Through numerical experiment, it is found that the newly proposed splitting method works well with a matrix-free formulation fer some bench mark problems avoiding an erroneous pressure field which appears when using the conventional pressure equation of a splitting method. When deriving a typical pressure equation of a splitting method, the motion of a solid particle has to be approximated by the 'intermediate velocity' instead of treating it as unknowns since it is necessary as a boundary condition. Therefore, the motion of a solid particle is treated in such an explicit way that a particle moves by the known form drag (pressure drag) that is calculated from the pressure equation in the previous step. From the numerical experiment, it was shown that this method gives an erroneous pressure field even for the very small time step size as a particle velocity increases. In this paper, coupling the unknowns of particle velocities in the pressure equation is proposed, where the resulting matrix is reduced to the symmetric one by applying the projector of the combined formulation. It has been tested over some bench mark problems and gives reasonable pressure fields.

• 상하수도학회지
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• 제20권2호
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• pp.197-206
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• 2006

The leakage in the water distribution system means both the loss of money and water resource. To minimize the leakage, we introduced the pressure control method using the pressure reducing valve and pump schedule. For the pressure control, the total leakage is needed to divide into each node. In this study, EPANET 2.0 was used to simulate the water networks in two selected blocks after the total leakage was distributed with each node by four ways. The leakage was allocated into each node as water measured by meter, water pressure, water faucets and Lpcd and simulated by EPANET 2.0. Regardless of the leakage distribution ways, there was no significant difference between the measured water and the estimated water pressure. Thus, the leakage distribution way using water pressures estimated by simulation could be recommended. The scenarios controlling the pressure reducing valve and pump were made in two blocks(A and B). $86,713m^3/year$ leakage in the A block and $11,442m^3/year$ in the B block could be reduced as controlling the pressure reducing valve and pump schedule. It was shown that the fifty million won a year can be saved in the A block and 6.8 million won in the B block.

• ALGAE
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• 제21권2호
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• pp.245-251
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• 2006

Diurnal and age-related changes in air pressure were measured in air bladders of Ascophyllum nodosum from the Atlantic coast of Nova Scotia. Exterior and interior bladder volumes vary significantly with 4 and 6 y bladders being about 40% larger than 2 y bladders (p < 0.01). Freshly collected bladders yielded a mean pressure of 40.8 ± 6.5 cm H2O. Overnight (20 h) dark treatment at 15°C generated pressure reductions by 80% in 2 y bladders but only by about 30% in 4 and 6 y bladders. Furthermore, in 2 y bladders 8 out of 11 bladders were reduced to atmospheric pressure. Pressure losses were inversely related to pressure recovery after 2.5 h in natural daylight, but after 5 h in daylight there was no significant difference in pressure within the age groups. Even under 25% of full illumination, bladders inflated to full pressure after 5 h. The results show that differences in bladder age and bladder wall thickness have roles in diurnal patterns of bladder inflation and deflation. These results confirm that bladder inflation is based on photosynthetic O2 production and not on partial pressures of O2 in the surrounding medium as was suggested for Sargassum. Chemical analyses of fluid recovered after the interior of bladders were washed with saline showed no evidence for the occurrence of surfactant that might be responsible for maintaining the air-liquid interface.