• Applied Biological Chemistry
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• v.11
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• pp.67-76
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• 1969

The reduced pressure storage of apple, American Summer Pairman, was investigated comparing with the other storage methods and the following results were obtained. 1. The reduced pressure storage was better to extend the storage life and freshness of apples than the controlled atomoshere storage. 2. Decreasing the pressure of chamber atmosphere to about 20 cmHg showed the best result among several pressure conditions. 3. As for the surface treatment of the apples, poly-ethylene film wrapping showed to be the most favorable method in a short-term experiment. In a long-term experiment, however, poly-ethylene film wrapping seemed to cause apples rot. Poly-vinyl acetate coating seemed to keep the apples from color changing, but it caused an unpleasant odor and a peculiar taste. No significant effect was observed in Gibberellin. 4. Total sugar and reduced sugar of apples were decreased after a certain period of increasing. Acid and Vitamin C, however, gradually decreased from the beginning of storage.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.527-532
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• 2016

The effects of gas velocity and solid circulation rate on the axial solid holdup distribution have been determined in a 10 mm-I.D. ${\times}$ 800 mm-high circulating fluidized bed plasma reactor under reduced pressure (1torr). Polystyrene polymer powder and nitrogen gas are used as solid and gas materials respectively. The change of solid circulation rate by a large gas flow rate of the riser (40~80 sccm) is also possible by a relatively small gas flow rate of the solid recirculation part (6.6~9.9 sccm). The solid circulation rate in the reactor under reduced pressure increases with increasing aeration velocity in the solid recirculation part. The axial solid holdup in the riser decreases from the dense at the bottom to the dilute phase at the top section of the riser. Solid holdups at the axial positions in the riser increase linearly with increasing solid circulating velocity. From these results, we could determine the position of plasma load for good plasma ignition, maintain and plasma reaction.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.75-84
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• 2002

In order to find out impact insulation properties, various types of current radiant floor heating systems and light-framed floors that are used in light-framed residential buildings were evaluated for two types of impact sources at the same time. Sound Pressure Level (SPL) was different from each impact sources for those spectrum patterns and peaks. In case of light-framed floor framework, the excitation position and the assumed effective vibrating area have effects on sound pressure level but it is not considerable, and Normalized SPL was reduced for each frequency by increasing the bending rigidity of joist. The mortar layer in the radiant heating system had relatively high density and high impedance, therefore, it distributed much of the impact power when it was excited, and reduced the Normalized SPL considerably. Nevertheless, Increasing a thickness of mortar layer had little influence on SPL. Ceiling components reduced the sound pressure level about 5~25 dB for each frequency. Namely, it had excellent sound insulation properties in a range from 200 to 4,000 Hz frequency for both heavy and lightweight impact sources. Also, there was a somewhat regular sound insulation pattern for each center frequency. The resilient channel reduced the SPL about 2~11 dB, irrelevant to impact source. Consequently, current radiant floor heating systems which were established in light-framed residential buildings have quite good impact sound insulation properties for both impact sources.

• Journal of computational fluids engineering
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• v.17 no.1
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• pp.36-43
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• 2012

When a high-speed train passes an underground station, large pressure waves are generated due to the piston effect. These pressure waves can cause the problems of vibration and noise as well as the ear discomfort of passengers at the underground station. This work numerically analyzed the pressure wave generation and propagation in an high-speed railway underground station, and the optimal location for vent shafts was studied to improve the passenger comfort by reducing the magnitude of the pressure wave and its rate of change. The evolution of pressure field in the underground station was calculated using a CFD(Computational Fluid Dynamics) software(Fluent), where the axis-symmetric two-dimensional model verified by Wu was used. And this study is applied to modelling of the underground station and the tunnel from Daegok station A-line of GTX(Great Train Express). From the result, we can have a conclusion that the role of vent shafts respectively were different according to the position in and out the underground station. Also Vent shaft in the underground station widely reduced pressure magnitude. And vent shaft out underground station reduced initial pressure peak value. Double vent shafts installed at tunnel toward station entrance and inside of the tunnel are the most efficient to reduce pressure. and pressure reduction increases according to the number of vent shaft.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.3
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• pp.378-385
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• 1999

A reduced NaCl intake for the general population of the world has been recommended to reduce the overall blood pressure level and hence to reduce the overall incidence of cardiovascular disease. A high NaCl diet convincingly contributes to elevated arterial pressure in humans and animal models of hypertension. Among individuals there is considerable variability of blood pressure responsiveness to NaCl intake. In normotensive as well as hypertensive subjects, blood pressure can be judged to be salt sensitivity (SS) when observed to vary directly and substantially with the net intake of NaCl. The prevalence of SS in normotensive adults in the U.S. ranges from 15% to 42% and in hypertensive adults from 28% to 74%. SS is a risk factor for hypertension and may be an important marker in the identification of children for hypertension prevention programs. High NaCl intakes produce expansion of the extracellular fluid volume and thus increase blood pressure. Nonchloride salts of sodium does not expand the extracellular fluid volume and does not alter blood pressure. Blood pressure response to NaCl may be modified by other components of the diet. Low dietary intakes of potassium or calcium augment NaCl-induced increases of blood pressure. Conversely, high dietary intakes of potassium or calcium attenuate NaCl-induced hypertension. A greater intakes of potassium or calcium may prevent or delay the occurrence of hypertension. SS occurs when dietary potassium is even marginally deficient but is dose-dependently suppressed when dietary potassium is increased within its normal range. Orally administered KHCO$_3$, abundant in fruits and vegetates, but not KCl has a calcium-retaining effect which may contributed to its reversal of pressor effect of dietary NaCl. Since nutrients other than NaCl also affect blood pressure levels, a reduced NaCl intake should be only one component of a nutritional strategy to lower blood pressure.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.140-147
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• 2008

An experiment setup was introduced to study dynamic behaviour of different types of check valves and the effects of air entrainment on the check valve performance under pressure transient condition. The experiment results show that the check valves with low inertia, assisted by springs or small traveling distance/angle gave better performance under pressure transient condition than check valves without these features. Air entrainment was found to affect both wave speed and reverse velocity. With the increase of the initial air void fraction in pipeline, the experiment results show that the wave speed was reduced, the reverse velocity was increased. The first peak pressure increased initially and then decreased with the increase of the initial air void fraction, the pressure surge periods were increased proportionally with air void fraction due to the greatly reduced wave speed. The study can be applied to help choosing suitable check valves for a particular pumping system.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.693-703
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• 2012

Leakage in water supply system can cause water resources loss in addition to the water quality degradation. In this research, leakage reduction after establishment of a block system in the area with leakage rate of 69.0 % was investigated using EPANET simulation. The average water pressure for the research area was $5.17kgf/cm^2$ which was relatively high, and several sites were deviated from recommended water pressure ranges(i.e., 1.5 ~ $7.1kgf/cm^2$). However, the average water pressure in the area was reduced to 3.81 and $3.49kgf/cm^2$ after the introduction of block system with a water pressure relief valve(PRV) setting of 3.0 and $2.5kgf/cm^2$, respectively. Under the installation of a PRV with regulating pressure of $2.5kgf/cm^2$, the predicted leakage was reduced from $4,420.3m^3/d$ to $3,028.1m^3/d$, which was equivalent to the leakage reduction from 31.0 % to 23.5 %.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.9
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• pp.1325-1334
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• 1998

The objectives of the present study are to develop a systematic method rather than a conventional trial-and-error method for an optimal shape design using a mathematical theory, and to apply it to engineering problems. In the present study, an optimal condition for a minimum pressure loss in a two-dimensional curved duct flow is derived and then an optimal shape of the curved duct is designed from the optimal condition. In the design procedure, one needs to solve the adjoint Navier-Stokes equations which are derived from the Navier-Stokes equations and the cost function. Therefore, a computer code of solving both the Navier-Stokes and adjoint Navier-Stokes equations together with an automatic grid generation is developed. In a curved duct flow, flow separation occurs due to an adverse pressure gradient, resulting in an additional pressure loss. Optimal shapes of a curved duct are obtained at three different Reynolds numbers of 100, 300 and 800, respectively. In the optimally shaped curved ducts, the separation region does not exist or is significantly reduced, and thus the pressure loss along the curved duct is significantly reduced.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.691-698
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• 2020

In this study, the effects of hydrodynamic interceptors on a high-speed vessel were investigated to identify the operating principle based on experiments. Model tests were performed using a high-speed towing carriage. The resistance, trim and rise of Center of Gravity (CG) of the high-speed vessel were measured for various ship speeds and interceptor heights. As the interceptor height increased, the trim and rise of CG were reduced. In order to quantitatively analyze these phenomena, the pressure at the stern bottom was measured using tactile sensors. The reliability of the measured results from the tactile sensors was verified through repeat tests. The pressure on the stern bottom increased in proportion to the interceptor height, as the interceptor partially blocked the flow there. Then, the trim was reduced. However, as the ship speed increases, the pressure at the location close to the interceptor decreases when the interceptor height is small, leading to increased trim. Therefore, the interceptor height for running attitude control should be carefully determined considering multiple factors in the operating condition of the high-speed planing hull.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.253-256
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• 1999

The influence of essential oils from aboriginal softwoods as Pinus densiflora, Pinus koraiensis, Chamaecyparis obtusa and Chamaecyparis pisifera on the motor coordination, pulse, mean blood artery pressure and pain reducing test was investigated in mice and rats. The motor coordination of mouse was not induced by the inhalation of each oil. Furthermore, these oils did not alter the changes of the mean blood pressure and pulse rate. Chamaecyparis pisifera trand to reduce the mean blood pressure. The abdominal pain induced by acetic acid was reduced only by an essential oil from Pinus koraiensis in mouse.