• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.3
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• pp.146-151
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• 2015

The heat transfer performance of heating medium oil fluidized bed heat exchanger was measured. The operation variables were air flow rate, air inlet temperature, moisture content, water flow rate and water inlet temperature. The outside heat transfer coefficient was determined from the heat exchanger experiment and its experimental correlation was determined as a function of air velocity and viscosity of heating medium oil. Effect of viscosity was well agreed with the previous studies. Errors of the correlation equation was less than about 10% for outside heat transfer coefficient developed in this study when compared with the measured value. Hot water with the temperature greater than $77^{\circ}C$ could be produced by using the heating medium oil fluidized bed heat exchanger.

• Environmental Engineering Research
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• v.25 no.4
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• pp.554-560
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• 2020

This study focuses on nitrification through a biological aerated filter (BAF) that is filled with a zeolite medium at low concentrations of ammonia. The zeolite medium consists of natural zeolite powder. The BAF is operated under two types of media, which are a ball-type zeolite medium and expanded poly propylene (EPP) medium. Nitrification occurred in the zeolite BAF (ZBAF) when the influent concentration of ammonia nitrogen was 3 mg L-1, but the BAF that was filled with an EPP medium did not experience nitrification. The ammonia nitrogen removal efficiency of ZBAF was 63.38% and the average nitrate nitrogen concentration was 1.746 mg/L. The ZBAF was tested again after a comparison experiment to treat pond water, and municipal wastewater mixed pond water. The ZBAF showed remarkable ammonia-nitrogen treatment at low concentration and low temperature. During this period, the average ammonia nitrogen removal efficiency was 64.56%. Especially, when water temperature decreased to 4.7℃, ammonia nitrogen removal efficiency remained 79%. On the other hand, the chemical-oxygen demand (COD) and phosphorus-removal trends were different. The COD and phosphorus did not show as efficient treatment as the ammonia-nitrogen treatment.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.193-198
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• 2011

We examined the effect of an artificial change of water temperature on the survival rate of Korean Scallop, Patinopecten yessoensis. As for the change of water temperature, the aspects appearing on the eastern coast of Korea during spring and summer were artificially prepared in the rearing aquarium in the laboratory. The survival rate of Scallop, due to the stimulus of a low water temperature in spring, was an average of 51.6%. Medium-sized scallops averaged 4.4%, which is lower than that of small-sized ones (85.82%) and large-sized ones (55.0%). The survival rate of Scallop, due to the stimulus of water at a high temperature in summer, was an average of 43.3%. As for small-sized scallops, they averaged a 46.7% survival rate which is lower than that of medium-sized scallops (60.0%). In general, the survival rate was lower in summer than in spring. Such results show that the death of Scallop, has close relevance to the change of water temperature. The low survival rate of medium-sized ones. Alternatively, medium-sized scallops have to get through winter, even if they cannot grow enough compared with large-sized ones. This is because large-sized scallops have already been adapted to the change of water temperature by getting through winter twice.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2228-2231
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• 2007

Water gas shift reactor in fuel processing is an important part that converts carbon monoxide into hydrogen. Fuel processing system for PEMFC usually has two stages of WGS reactors, which are high temperature and low temperature shifter. In this study we prepared noble metal catalysts and compared their performances with that of a commercial iron chromium oxide catalyst. Noble metal catalysts and the commercial catalyst showed quite different temperature dependence of carbon monoxide conversion. The conversion of carbon monoxide at the commercial catalyst was very low at medium temperature(${\sim}300^{\circ}C$) and increased rapidly as temperature increased while the conversion at noble metal catalysts was high in the medium temperature range and decreased as temperature increased, which is thermodynamically expected. Their characteristics agreed well with the literature published, and we are accomplishing further study for improvement of the noble metal catalysts.

• Korean Journal of Microbiology
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• v.6 no.4
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• pp.113-121
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• 1968

This study has been aimed to determine the ecological factors with relationship to the Jongkok production in view of fermentation technology by means of some strains, Asp. kawachii, which is now preserved by the author and the following factors are included during the study; inorganic salts, nitrogen, sugar, water contents and temperature. The results, are as follows: (a) Sugar among other above-mentioned factors is increasingly affecting the number of the short type of conidiophore on culture medium and the conidiophore is increased by direct ratio until glucose concentration of 50%, at which concentration is mostly effective for the short type of conidiophore, while other factors did not affect on it. (b) Until glucose concentration of 50% sugar component of culture medium is favorable for the spore formation of Asp. kawachii by direct ratio. And peptone or asparagine on nitrogen medium, calcium-phosphate among other inorganic salts, wheat bran and rice branare also favorable, but other factors rientioned earlier show no relationship with the spore formation. Sugar, however, also related with the spore color clearness of crimson and light brown, and spore color is mostly clear at the point of glucose concentration until 50%. And asparagine on nitrogen medium, calcium phosphate among other inorganic salts, rice bran did all affect on the color clearness, while other factors did not concern with color clearness. (c) Water, sugar and temperature have related with the acid formation which is promoted, by direct ratio at the point of water-saturated condition and glucose concentration of 50%, while temperature at $25^{\circ}C$favorably affected on the acid formation which is increased by inverse ratio at the temperature$25^{\circ}C$ to $45^{\circ}C$ And pH did not relate with the acid formation. (d) Cylindrical plate method devised by the author is mostly favorable for the preservation and isolation of culture, compared with the traditional slant medium method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1034-1041
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• 2001

A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.138-144
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• 2000

The studies were carried out to investigate the effects of esophageal thermal tube for rewarming in the hypothermia in rabbits. Thiry-one rabbits were continuously cooled with femoral arterio-venous bypass circulation to 25.0${\pm}$0.3$^{\circ}C$(profound hypothermia) of rectal temperature. The experiment was consisted with 3 esophageal thermal tube groups perfused with circulation water at 38${\pm}$1$^{\circ}C$(low, n=12), 42${\pm}$1$^{\circ}C$(medium, n=12), and 45${\pm}$1$^{\circ}C$(high, n=7). Esophageal thermla tube specially constructed double-lumen esophageal tube with circulating warm water at respective htermal grade. With this device, rewarming of the rabbits as follows; High-esophageal thermal tube group(45${\pm}$1$^{\circ}C$)had a more effect on mean arterial pressure(MAP), heart rate(HR), esophageal temperature, and rectal temperature than others groups, but the circulation water at 45$\pm$1$^{\circ}C$ may cause thermal injuries in the esophagus because esophageal temperature increased to 41.1$^{\circ}C$. Medium-esophageal thermal tube group(42${\pm}$1$^{\circ}C$) had a more effect on RR than others groups, but the circulation water at 42${\pm}$1$^{\circ}C$ may also cause thermal injuries in the esophagus if the temperature exceeds 42$^{\circ}C$ for an extended period of time because its esophageal temperature increased to 39.4$^{\circ}C$. Low-esophageal thermal tube group(38${\pm}$1$^{\circ}C$) had a more effect on MAP, RR, and esophageal temperature than others groups. In conclusion, rewarming of the central core in the treatment of profound hypothermia using the esophageal thermal tube perfused with circulation water at 38${\pm}$1$^{\circ}C$ appears to be a ideal alternative safety zone of the temperature of circulation water avoiding thermal injury in esophagus causing by out of order or lower precise thermostat of water bath to that of others groups.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1110-1119
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• 2006

If water flows through a narrow passage into a medium that keeps the equilibrium of temperature, it causes small temperature difference and makes a temperature anomaly. The seepage or leakage often observed at old dams is a representative example of bringing about a temperature anomaly. Therefore, temperature measurements have been regarded as one of excellent methods that can detect the situation of seepage or leakage. However, because existing temperature measurement methods are based on a single sensor, the application of the method to the whole structure is nearly not possible in technical and economical phases. This paper introduces a temperature monitoring system using a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel at many positions within a single cable. Through various laboratory and field experiments, it has been proved that the temperature monitoring technique can give an useful information about permeability of a medium or connectivity of fractures which have been regarded as difficult problems.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.614-615
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• 2007

There are roughly a hundred types of cables in power plants. The distribution of circuits in a nuclear plant is comprised of 20% instrument cables, 61% control cables, 13% AC power cables, 1% DC power cables, and 5% communication lines. In the nuclear power plant, medium voltage cables are generally included in the scope of systems reviewed for safety and are included in a plant's maintenance program. Medium voltage cables provide power to many critical components in plants, including feed water pumps, circulating water pumps, and condensate pumps. Among these cables, high temperature sections of cables feeding electrical power to the circulating water pump and the condenser extraction pump were found. The evaluation for these cables is performed to find the maximum allowable current and temperature. The result shows that the load current flowed about 85% of the allowable current ampacity, and the temperature of conductor at full load current did not exceed the limited temperature. Therefore, existing cables for circulating water pump and condenser extraction pump system are going to be used during design life.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.208-214
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• 2003

Four species of water fleas (Daphnia magna, Daphnia pulex, Daphnia galeata, and Moina macrocopa) were examined for the clarification of their reproduction with culture conditions. The reproduction tests of water flea by the culture conditions were carried out. For the comparison of the reproduction rate, five media (manure-soil medium, DIN medium, M4 medium, EPA medium, fertilizer medium) were applied to determine the best medium. Daphnia magna, Daphnia pulex, and Moina macrocopa were appeared the best reproduction in the manure-soil medium at $20^{\circ}C.$ The lifespan and young reproduction were better in manure-soil medium than the others. But Daphnia galeata was lived for 34 days in the fertilizer medium at $20^{\circ}C.$ The culture of Daphnia galeata was difficult to rear than the other species. In the current study, the microcystin of Microcystis sp. did not particularly affect on the survival of water fleas. But the lifespan was short and the reproduction rate was low. Therefore water flea have a preference for Scenedesmus sp. than Microcystis sp. On the condition of the feeding Scenedesmus sp., all examined water fleas appeared to have the longest lifespan and the most young water fleas produced at any medium and temperature as compared with the feeding the Microcystis sp. For the culture temperature, the lifespan was longer on $20^{\circ}C$ than $15^{\circ}C$.