• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.197.1-197.1
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• 2011

Target generation capacity of geothermal power generation pilot plant project through the Enhanced Geothermal Systems (EGS) with a doublet system down to 5 km depth was estimated. Production and re-injection temperatures of geothermal fluid were assumed $160^{\circ}C$ and $60^{\circ}C$, respectively, based on reservoir temperature of $180^{\circ}C$ calculated from the geothermal gradient of $33^{\circ}C$ in Pohang area. In this temperature range, 0.11 of thermal efficiency of the binary generation cycle is a practical choice. Assuming flow rates of 40 kg/sec, which is possible in current EGS technology, gross power generation capacity is estimated to reach 1.848 MW. Net generation considering auxiliary power including pumping power for geothermal fluid and condensing (cooling) energy of working fluid can be 1.5 MW.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.220.2-220.2
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• 2011

Biodiesel and biodiesel blend fuel are receiving increasing attention as alternative fuels for diesel engines without substantial modifications. Biodiesel fuels and blending have been widely studied and applied in diesel engine because of biodiesel's lower sulfur, lower aromatic hydrocarbon and higher oxygen content. Biodiesels have the potential to be oxidized in different condition. It has reported that oxidation deterioration of biodiesel is different in the condition of storage and oxidation causes chemical property change of methyl esters. Sunlight intensity, temperature, material of container and contact surface with oxygen are key dominant factors accelerating oxidation deterioration. In this study, we chose temperature among key oxidation conditions and metal container filled with biodiesel was heated at about $110^{\circ}C$ for 10 days in order to accelerate oxidation deterioration. To better understand the effect of biodiesel blends on emission, steady state tests were conducted on a heavy duty diesel engine. The engine was fueled with Ultra Low Sulphur Diesel(ULSD), a blend of 10% and 20%(BD10, BD20) on volumetric basis, equipped with a common rail direct injection system and turbocharger, lives up to the requirements of EURO 3. The experimental results show that the blend fuel of normal biodiesel with BD10 and BD20 increased NOx. The result of PM was similar to diesel fuel on BD10, but the result of PM on BD20 was increased about 63% more than its of diesel. The blend fuel of Oxidation biodiesel with BD10 and BD20 increased NOx as the results of normal biodiesel. But PM was all increased on BD10 and BD20. Especially THC was extremely increased when test fuel contains biodiesel about 140% more than its of diesel. Through this study, we knew that oxidation deterioration of biodiesel affects emission of diesel engine.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.269-274
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• 2007

A prior fundamental study was executed using a constant volume chamber (CVC) to improve the burning characteristics of lean pre-mixture by the injection of active radicals generated in the sub-chamber of the CVC. The Radical ignition (RI) technique shows remarkable progress in the burning velocity and combustible lean limit compared with the results of the spark ignition (SI) technique. The optimum design value of the sub-chamber geometry is near $0.11cm^{-1}$ for the ratio of the total area of the holes to the sub-chamber volume $(A_h/V_s)$. In this study, based on the former experimental results, the additional works have been performed to examine the effects of the geometry change in the number $(N_h)$, the total section area $(A_h)$, and diameter $(D_h)$ of the passage holes on the combustion characteristics in the CVC. Also ambient conditions such as the initial temperature and the initial pressure of the mixture were selected as experimental parameters and the effects of residual gas at the chamber on the combustion characteristics were investigated. As a result, the correlation between the passage hole number and overall passage hole area was grasped. The effects of the initial temperature were significant, but on the other hand, those of the initial pressure were weak. A more detailed analysis on the residual gas is required in the future.

• The Korean Journal of Pain
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• v.14 no.2
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• pp.164-170
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• 2001

Background: Infrared Thermal Imaging (ITI) is an effective tool for the diagnosis of disease and evaluation of the therapeutic effects following pain treatment. Patients who were treated for pain in pain clinic described the intensity of pain and the degree of change of their pain using a visual analogue scale (VAS). In this study, the usefulness of ITI following multimodal methods for pain management were compared with the change of VAS. Methods: 1119 patients were evaluated. The patients were treated with stellate ganglion block, epidural block or trigger points injection. Before treatment, the temperature difference (${\Delta}T$) of the involved area and the corresponding area on the opposite side of the body was measured using ITI and VAS was assessed. After treatment, the temperature difference (${\Delta}T$) between the normal and involved areas, the change of ${\Delta}T$ (${\Delta}dT$), VAS and the change of VAS (${\Delta}VAS$) were measured. Statistic correlations between ${\Delta}dT$and ${\Delta}VAS$ were calculated in all groups. Results: Correlation of the ${\Delta}dT$ and ${\Delta}VAS$ was significant by contingency coefficient test. (SGB group, C = 0.358, Epi group, C = 0.377, TPI group, C = 0.374, P < 0.05) Conclusions: ITI is a reliable tool for the assessment of therapeutic effects following multidimensional management of painful disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.623-632
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• 2018

Predicting the behavior of rheological polymers is highly shear rate- and temperature-dependent. The Cross-WLF viscosity model has become a powerful solution that describes the shear rate- and temperature-dependent characteristics. To estimate the behavior of polymers in computational simulations, the coefficients of the Cross-WLF model should be well identified. An identification technique was proposed to determine the Cross-WLF viscosity model coefficient. The assumption is that the Cross-WLF viscosity model well describes the real characteristics of polymers when the calculated viscosity with the parameters is identical to the reference data. In this study, Auto-desk Moldflow data were used as a reference. The numerical examples showed that the proposed method accurately identifies the Cross-WLF viscosity model coefficients.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.648-655
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• 2003

In this study, the effects of Gamgung-tang gamibang on the hyperthyroidism induced by the intraperitoneal injection of 3,5,3-triiodothyronine was examined by the measurement of physical changes, body weight, the volume of food intake and rectal temperature, and heart weight, heart beat, blood pressure with contrast to propranolol, one of beta-blocking agents. the obtained results were as follows. The Gamgung-tang gamibang extract showed to inhibit the decrease of body weight and rectal temperature, and decrease the food intake, so the inhibitory effects of Gamgung-tang gamibang extract on the experimental hyperthyroidism were exhibited. The Gamgung-tang gamibang extract showed the inhibitory effects on the circulatory functions changed and enhanced by the experimental induced hyperthyroidism, the action of Gamgung-tang gamibang extract was less effective than the propranolol of D-CONT group. The Gamgung-tang gamibang extract showed significant effects to inhibit the concentration of serum thyroid houmone, more effective than the propranolol, beta-blocking agents. The Gamgung-tang gamibang extract showed the effective inhibitory reaction on the biochemical changes in serum, cholesterol, ketone bodies, free fatty acid, glucose in hyperthyroid rats induced by 3,5,3-triiodothyronine.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.707-716
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• 2008

The objective of this study was to analyze the effect of mixed fuel composition and mass fraction on spray inner structure in evaporating transient spray under the variant ambient conditions. Spray structure and spatial distribution of liquid phase concentration were investigated using a thin laser sheet illumination technique on the three component mixed fuels. A pulsed Nd:YAG laser was used as a light source. The experiments were conducted in a constant volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. Used fuel contains i-octane($C_8H_{18}$), n-dodecane($C_{12}H_{26}$) and n-hexadecane($C_{16}H_{34}$) that were selected as low-, middle- and high-boiling point fuel, respectively. Experimental conditions are 42 MPa, 72 MPa and 112 MPa in injection pressure, $5\;kg/m^3$, $15kg/m^3$ and $30kg/m^3$ in ambient gas density, 300 K, 500 K, 600 K and 700 K in ambient gas temperature, 300 K and 368 K in fuel temperature and different fuel mass fraction. Experimental results indicated that the multi-component fuels made two phase region mixed vapor and liquid so that it would are helpful to improve combustion, for the fuels of high boiling point component could accelerate evaporation very much according as low boiling point fuel was added to high boiling point fuel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.689-696
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• 2010

The Because of its high thermal efficiency, the direct injection (DI) diesel engine has emerged as a promising potential candidate in the field of transportation. However, the amount of nitrogen oxides ($NO_x$) increases in the local high-temperature regions and that of particulate matter (PM) increases in the diffusion flame region during diesel combustion. In the de-$NO_x$ system the Lean $NO_x$ Trap (LNT) catalyst is used, which absorbs $NO_x$ under lean exhaust gas conditions and releases it in rich conditions. This technology can provide a high $NO_x$-conversion efficiency, but the right amount of reducing agent should be supplied to the catalytic converter at the right time. In this research, the emission characteristics of a diesel engine equipped with a micro-reformer that acts as a reductants-supplying equipment were investigated using an LNT system, and the effects of the exhaust-gas temperature were also studied.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.48-54
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• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale liquid rocket engine using liquid oxygen(LOx) and Jet A-1(Jet engine fuel) as propellants. Film coolants(Jet A-1 and water) was injected through the film cooling injector. The outside wall temperature of the combustor and film cooled length were determined for chamber pressure, mixture ratio, and the different geometries(injection angle) with the percent film coolant flow rate. The loss of characteristic velocity was determined for the case of film cooling with water and Jet A-1. As chamber pressure increased, the outside wall temperature increased in the nozzle but unchanged over the 9 percent film coolant flow rate for the combustion chamber used in this study. Characteristic velocity wasn't affected with the mixture ratio over the 9 percent film coolant flow rate.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.82-91
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• 1992

The examination of the pollutants originated from domestic sewage, industrial and agricutural activities the existences of some toxic heavy metals, organic matters and pathogenic microorganisms. A recent report of WHO brought out that such pollutants are in existence with above roughly 2,000 kinds of chemical substances and amongst them about 750 chemicals have been indentified by drinking water. And above 600 kinds of them are organic pollutants and in addition these include carcinogenic mutagenic and poisonous substances. This is not intended to embody a study of broad confined to various approaches on organic materials, and therefore will be THM produced on injection of chlorine at water filtration plant. To specify the relations between THM and factors having an effect upon THM such as TOC, Cl$_{2}$, Temperature, pH and reaction time, first of all the recovery ratio for analytical methods of THM (Head sapce, purge and trap, Liquid/ Liquid Extraction methods) was investigated. Provided that by using it,the correction coefficients are obtained, the accuracy of data might be able to be enhanced through analysis.The result of the experiments are given in the followings. 1) Among three kinds of analytical methods, recovery rate was higher in order of purge and trap Liquid/Liquid Extraction, Head space. There is no great difference in recovery rate among three methods. 2) The higher the concentration of TOC, the more the amount of THM. 3) The higher the reaction temperature, the more the amount of THM. 4) The longer the reaction time, the more the amount of THM. 5) The higher the pH, the more the amount of THM. 6) The higher the concectration of chlorine, the more the amount of THM.