• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.301-312
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• 1999

Experiments were carried out to evaluate performance of the cold air distribution systems with an ice storage tank in test room. Cold air distribution systems provide primary air for comfort conditioning or process cooling at coil discharge temperatures$4^{\circ}C$ to$11^{\circ}C$. The application of a cold air distribution system allows for the downsizing of air distribution equipment and central plant equipment when ice storage tank is used. The benefit of a cold air distribution system include a decrease in the floor-to-floor height, increase floor space, reduced building capital costs, reduced energy use and demand. The use of cold air distribution can result in the most cost effective system and is currently being implemented world wise as the new standard in air conditioning systems. In this study, the cold air distribution system is compared with the general ice storage system. Under the same cooling load conditions, experimental results show that the supply air volume of cold air distribution system decrease 38%, and decrease 45% flow rate of brine for the general ice storage system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1264-1276
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• 2000

Light-off catalyst has been used for minimization of cold-start emissions. Improved cold-start performance of light-off catalyst needs the optimal design in terms of flow distribution, geometric surface area, precious metal loading, cell density and space velocity. In this study, these influential factors are numerically investigated using integrated numerical technique by considering not only 3-D fluid flow but also heat and mass transfer with chemical reactions. The present results indicate that uneven catalyst loading of depositing high active catalyst at upstream of monolith is beneficial during warm-up period but its effect is severely deteriorated when the space velocity is above 100,000 $hr^{-1}$ To maximize light-off performance, this study suggests that 1) a light-off catalyst be designed double substrate type; 2) the substrate with high GSA and high PM loading at face be placed at the front monolith; and 3) the cell density of the rear monolith be lower to reduce the pressure drop.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.44-51
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• 2006

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.31-37
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• 2006

Objectives & Methods : We investigated the cases for which spleen tonifying Sa-Am acupuncture was applied in ${\ulcorner}$Sa-Am-chim-gu-jeong-jeon(舍巖鍼灸正傳)${\lrcorner}$ and classified them according to the concepts of cold-heat & deficiency-excess for a better understanding of the application of spleen tonifying Sa-Am acupuncture. Results : 1. Tonification of Spleen Sa-Am acupuncture can be used to treat heat syndromes such as deficient fire caused by collapse of the spleen qi, stagnation of evil qi or spleen yin deficiency, by way of tonifying spleen qi, activating the flow of qi and blood or harmonizing spleen yin and yang. 2. Tonification of Spleen Sa-Am acupuncture can be used to treat cold syndromes such as weakness of spleen yang by way of promoting fire to generate earth, strengthening spleen yang and raising the clear yang. 3. Tonification of Spleen Sa-Am acupuncture can be used to treat deficiency syndromes such as malnutrition or poor appetite caused by spleen deficiency by way of tonifying spleen qi. 4. Tonification of Spleen Sa-Am acupuncture can be used to treat excess syndromes such as stagnation of qi and blood, abdominal mass or toxication by way of tonifying spleen qi and promoting the flow of qi and blood.

• Korean journal of food and cookery science
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• v.4 no.2
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• pp.71-79
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• 1988

This study is written to look into microbiological quality by passage of time and holding methods after making foods, by means of evaluating time, temperature and microbiological quality during various phases in product flow of cold soybean noodles serviced by an industry feeding operation for 500 persons a day, measuring pH & Aw and analyzing factors affecting microbiological growth conditions. The results were as follows: 1. According to phases in product flow of cold soybean noodles, it showed 15.6 hours of mean of needed time, $24.2^{\circ}C$ of room temperature, 5.1~7.6 of pH value & 0.95~0.98 of Aw except dry noodles. These conditions were good for multipling of microbe, and the phases with potential sanitary danger were ingredient, pre-preparation, holding before assembly and service and assembly & service. 2. As for holding methods and passage of time, holding at cold table was more effective than holding at room temperature as time past. 3. As for equipments using for making food, dipper, basket, kitchen board & kitchen towel showed high microbiological value in total aerobic plate counts and kitchen towel and stainless-steel were showed high microbioloical value in coliform counts. 4. E. coli, food poisoning bacteria was detected from barrel filled with soybean soup and also soybean itself.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.768-775
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• 2022

In this study we aimed to derive the response surface models for Escherichia coli reduction in wheat flour using atmospheric cold plasma (ACP) with three types of gas. The jet-type atmospheric cold plasma wand system was used with a 30 W power supply, and three gases (argon, air, and nitrogen) were applied as the treatment gas. The operating parameters for process optimization considered were wheat flour mass (g), treatment time (min), and gas flow rate (L/min). The wheat flour samples were artificially contaminated with E. coli at a concentration of 9.25 ± 0.74 log CFU/g. ACP treatments with argon, air, and nitrogen resulted in 2.66, 4.21, and 5.55 log CFU/g reduction of E. coli, respectively, in wheat flour under optimized conditions. The optimized conditions to reduce E. coli were 0.5 g of the flour mass, 15 min of treatment time, and 0.20 L/min of nitrogen gas flow rate, and the predicted highest reduction level from modeling was 5.63 log CFU/g.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.767-776
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• 1985

Unsteady thermally stratified flow caused by two-dimensional surface discharge of warm water into a oblong channel was investigated. Experimental study was focused on the rapidly developing thermal diffusion at small Richardson number. The basic objective were to study the interfacial mixing between a flowing layer of warm water and an underlying body of cold water and to accumulate experimental data to test computational turbulence models. Mean velocity field measurements were carried out by using NMR-CT (Nuclear Magnetic Resonance-Computerized Tomography). It detects quantitative flow image of any desired section in any direction of flow in short time. Results show that at small Richardson number warm layer rapidly penetrates into the cold layer because of strong turbulent mixing and instability between the two layers. It is found that the transfer ofheat across the interface is more vigorous than that of momentum. It is also proved that the NMR-CT technique is a very valuable tool to measure unsteady three dimensional flow field.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.276-281
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• 2019

The process of separating oxygen and nitrogen from the air is mainly performed by electric liquefaction, which consumes a lot of electricity, resulting in higher operating costs. On the other hand, when used for cold energy of LNG, electric power can be reduced compared to the electric Linde cycle. Currently, LNG cold energy is used in the cold refrigeration warehouse, separation of air-liquefaction, and LNG cold energy generation in Japan. In this study, the system using LNG cold energy and the Linde cycle process system were simulated by PRO/II simulators, respectively, to cool the elevated air temperature from the compressor to about $-183^{\circ}C$ in the air liquefaction separation process. The required amount of electricity was compared with the latent heat utilization fraction of LNG, the LNG supply pressure, and the LNG cold energy usage. At the air flow rate of $17,600m^3/h$, the power source unit of the Linde cycle system was $0.77kWh/m^3$, compared with $0.3kWh/m^3$.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.133-135
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• 2003

Cryogenic systems are requirement for the operation of HTS power cables. In general, HTS power cables require temperature below 77K, a temperature that can be achieved from the liquid nitrogen at latm or sub-cooled LN2 above latm. HTS power cable needs sufficient refrigeration to overcome its low temperature heat loading. This loading typically cones in two forms : (1) heat leaks from the surroundings and (2) internal heat generation. This paper explains the cooling test system of 10m HTS power cable. This system is composed of storage dewar, auto fill system, core cryostat and cold-box. Storage dewar is a LN2 storage tank and auto fill system is a LN2 supply device to the sub-cooler, Core cryostat is a LN2 flow line. Cold box is a control unit of temperature and flow rate. It is composed of control valve, flow meter, sub-cooler and circulation pump, etc..