• Journal of Korean Society on Water Environment
• /
• v.31 no.2
• /
• pp.151-158
• /
• 2015

The aim of this research is to derive an optimum operating condition for the thermal solubilization equipment that is employed to increase concentration of soluble organic materials and to assess whether it would be possible to use the waste sludge generated by thermal solubilization reaction as an external carbon source in biological denitrification process. For the purpose, we have constituted a laboratory-size thermal solubilization equipment and have assessed thermal hydrolysis efficiency based on various reaction temperature and reaction time. We have also derived SDNR using the waste sludge generated by thermal solubilization reaction through a batch experiment. As a result of research, the highest thermal hydrolysis efficiency of about 42.8% was achieved at $190^{\circ}C$ of reaction temperature and at 90 minutes of reaction time. And when SDNR was derived using the waste sludge, the value obtained was $0.080{\sim}0.094\;g\;NO_3{^-}-N/g\;MLVSS{\cdot}day$, showing SDNR that is higher than that obtained by the results of existing researches that used common wastewater as an external carbon source. Accordingly, in view of the fact that food wastes vary quite a bit in characteristics based on the area they are generated from and seasonal change, it seems that a flexible operation of thermal solubilization equipment is required through on-going monitoring of food wastes that are imported to food wastes recycling facilities.

• Child Health Nursing Research
• /
• v.6 no.3
• /
• pp.397-410
• /
• 2000

This is a nonequivalent control group pretest- posttest design in quasi experimental basis to assess how the thermal head and feet support influences on early stage weight gain in premature neonates. The clients were selected among the premature infants with the weight under 2000gms and with the gestational period under 37 weeks, admitted over 15 days in K university hospital, Seoul. The control group of 29 were selected from January 1998 to August 1998, who were without head and feet thermal support, and the experimental group of 30 were selected from September 1998 to May 1999, who were with the two thermal interventions. The results of the study follow, 1.The experimental group with thermal interventions showed more weight gain than the control group without thermal interven- tions, which was statistically significant between the two groups. 2.The physiological weight loss after birth showed less in the experimental group than in the control group. 3.The recovery of the birth weight after the physiologic weight loss showed no statistical difference between the experimental group and the control group. Consequently, the thermal head and feet supportive nursing intervention could be applied as a nursing intervention program to help the premature neonates' development. With the results above we should like to suggest the following: 1) A continuous application in the practice of our thermal supportive intervention for the premature neonates, a development of the content through evaluation, and a comparision of the results through a long time study. 2) A neccessity of deveopment of various study and cross comparision. 3) A neccessity of multi-angular study on the premature infants' characteristics influencing the thermal therapy and the study of the individual differences of the clients.

• 한국연소학회:학술대회논문집
• /
• 1997.06a
• /
• pp.69-76
• /
• 1997

Industrial-scale pulse corona process to remove $SO_2$ and $NO_x$ simultaneously from combustion flue gas has been studied. The pilot plant built in the present study treats 2,000 $Nm^3$/hr of flue gas from a boiler. The geometry of the pulse corona reactor is similar to that of an electrostatic precipitator commonly used in industry, A thyratron switch and magnetic pulse compressors, which can generate up to 130 kV of peak pulse voltage and up to 30 kW of average pulse power, have been used to produce pulsed corona. The removal efficiencies of $S0_2$ and $NO_x$ with the present process are maximum of 95 % and 85 %, respectively. Electrical power consumption to produce the pulsed corona, which has been one of the major difficulties to apply this process to industry, has been evaluated in the present study. The results showed that the power consumption can be reduced significantly by simultaneous addition of hydrocarbon injection and heterogeneous phase reactions to the process.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.3
• /
• pp.74-80
• /
• 2017

As for A rotary wing aircraft, the configuration change about split yaw swaged rod was executed to improve hit treat capability for dealing with a long rod. The purpose of this study was to analyze if or not the quality of the split yaw swaged rod was obtained, and so the flight safety was ensured or not. Buckling analysis, Coupling Thread Strength Analysis, Thermal Stress analysis and Rod Natural Frequency Analysis were executed for structural analysis. The results of the analysis were presented that the split rod had the sufficient margin of safety and so there were no anomalies in the limit load and no failures in the ultimate load. And there were no resonances in result of natural frequency analysis. In conclusion, this study showed that the split yaw swaged rod had structural safety, so flight safety of rotary wing aircraft was secured and there was no problem in aircraft operation. It is certain that the technology of splitting the yaw swage rod will contribute to the operational Safety of the rotary wing aircraft in the future.

• Journal of the Korean Society of Industry Convergence
• /
• v.4 no.4
• /
• pp.403-411
• /
• 2001

A criterion for evaluation of burners has changed recently, and the environmental problems are raised as a global issue. Burners with higher thermal efficiency and lower oxygen in the exhaust gas, evaluated better. To comply with environmental regulations, burners must satisfy the $NO_x$ and CO regulation. Consequently. 'good burner' means one whose thermal efficiency is high under the constraint of $NO_x$ and CO consistency. To make existing burner satisfy recent criterion, it is highly recommended to develop a feedback control scheme whose output is the consistency of $NO_x$ and CO. This paper describes the development of a real time flame diagnosis technique that evaluate and diagnose the combustion states, such as consistency of components in exhaust gas, stability of flame in the quantitative sense. In this paper, it was proposed on the flame diagnosis technique of burner using Neuro- Fuzzy algorithm. This study focuses on the relation of the color of the flame and the state of combustion. Neuro- Fuzzy learning algorithm is used in obtaining the fuzzy membership function and rules. Using the constructed inference algorithm, the amount of $NO_x$ and CO of the combustion gas was successfully inferred.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.4
• /
• pp.587-595
• /
• 2002

Recent trend changes a criterion for evaluation of humors that environmental problems are raised as a global issue. Burners with higher thermal efficiency and lower oxygen in the exhaust gas, evaluated better. To comply with environmental regulations, burners must satisfy the NO/sub x/ and CO regulation. Consequently, 'good burner'means one whose thermal efficiency is high under the constraint of NO/sub x/ and CO consistency. To make existing burner satisfy recent criterion, it is highly recommended to develop a feedback control scheme whose output is the consistency of NO/sub x/ and CO. This paper describes the development of a real time flame diagnosis technique that evaluate and diagnose the combustion states, such as consistency of components in exhaust gas, stability of flame in the quantitative sense. In this paper, it was proposed on the flame diagnosis technique of burner using Neuro-Fuzzy algorithm. This study focuses on the relation of the color of the flame and the state of combustion. Neuro-Fuzzy loaming algorithm is used in obtaining the fuzzy membership function and rules. Using the constructed inference algorithm, the amount of NO/sub x/ and CO of the combustion gas was successfully inferred.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.4
• /
• pp.384-391
• /
• 2007

Hydrogen-blending effects in flame structure and NO emission behavior are numerically studied with detailed chemistry in methane-air counterflow diffusion flames. The composition of fuel is systematically changed from pure methane to the blending fuel of methane-hydrogen through $H_2$ molar addition up to 30%. Flame structure, which can be described representatively as a fuel consumption layer and a $H_2$-CO consumption layer, is shown to be changed considerably in hydrogen-blending methane flames, compared to pure methane flames. The differences are displayed through maximum flame temperature, the overlap of fuel and oxygen, and the behaviors of the production rates of major species. Hydrogen-blending into hydrocarbon fuel can be a promising technology to reduce both the CO and $CO_2$ emissions supposing that NOx emission should be reduced through some technologies in industrial burners. These drastic changes of flame structure affect NO emission behavior considerably. The changes of thermal NO and prompt NO are also provided according to hydrogen-blending. Importantly contributing reaction steps to prompt NO are addressed in pure methane and hydrogen-blending methane flames.

• Journal of the Korean Chemical Society
• /
• v.40 no.2
• /
• pp.101-108
• /
• 1996

The chemical characteristics and age dating of the thermal springwater developed recently in Chullabukdo were investigated. The temperature range of the thermal springwater was found 27∼29$^{\circ}C$, indicating a low temperature thermal springwater. The concentration of $F^-$ ion in the springwater was found relatively high in the range of 2∼3 ppm, but $NO_3^-$ ion was nearly not detected. The concentration range of $SO_4^{2-}$ ion was 0.02∼23 ppm, among which $SO_4^{2-}$ content of $Y_3$ was found very high compared to that of other springwater, since this site is known as a sulfur spring. $HCO_3^-$ ion content was found 2∼5 times higher than that of groundwater. $Y_1,\;Y_3,\;Y_5,\;Y_2,\;Y_4,\;and\;Y_8$, were classified as $HCO_3^-$ type, $Y_6$ as $CI^-$type, and $Y_7$, as no domonant type by classification diagram for anion and cation facies. From the results of age dating on the basis of the mean tritium level of precipitation and thermal springs, $Y_1$ was identified as the oldest thermal spring (-89 years) and $Y_7$ was identified as -89 years and $Y_7$ was -1 year using dispersive model. The results calculated by two models agreed well each other.

• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.6
• /
• pp.699-713
• /
• 2003

Statement of problem. Titanium is the most important material for biomedical and dental implants because of their high corrosion resistance and good biocompatibility. These beneficial properties are due to a protective passive oxide film that spontaneously forms on the surface. Purpose. The purpose of this study was to evaluate the responses of osteoblast-like cells on different surface treatments on Ti discs. Material and Methods. Group 1 represented the machined surface with no treatment. Group 2 surfaces were sandblasted with $50{\mu}m\;Al_2O_3$ under $5kgf/cm^2$ of pressure. Groups 3 and 4 were sandblasted under the same conditions. The samples were treated on a titanium oxide surface with reactive sputter depositioning and thermal oxidation at $600^{\circ}C$ (Group 3) and $800^{\circ}C$ (Group 4) for one hour in an oxygen environment. The chemical composition and microtopography were analyzed by XRD, XPS, SEM and optical interferometer. The stability of $TiO_2$ layer was studied by petentiodynamic curve. To evaluate cell response, osteoblast extracted from femoral bone marrow of young adult rat were cultured for cell attachment, proliferation and morphology on each titanium discs. Results and Conclusion. The results were as follows : 1. Surface roughness values were, from the lowest to the highest, machined group, $800^{\circ}C$ thermal oxidation group, $600^{\circ}C$ thermal oxidation group and blasted group. The Ra value of blasted group was significantly higher than that of $800^{\circ}C$ thermal oxidation group (P=0.003), which was not different from that of $600^{\circ}C$ thermal oxidation group (P<0.05). 2. The degree of cell attachment was highest in the $600^{\circ}C$ thermal oxidation group after four and eight hours (P<0.05), but after 24 hours, there was no difference among the groups (P>0.05). 3. The level of cell proliferation showed no difference among the groups after one day, three days, and seven days (P>0.05). 4. The morphology and arrangement of the cells varied with surface roughness of the discs.

• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.117-121
• /
• 2006

Non-thermal plasma technology has many applications in various areas. One of the applications is regenerating diesel particulate filter (DPF). DPF is a widely applied device to control the particulate emission of diesel engines. But it needs periodic removal of clogged soot for the smooth running of engine. Conventional high-temperature removal processes easily leads to the breakage of DPF. Herein, low-temperature plasma formed in a dielectric barrier discharge (DBD) reactor was used to form active oxidants such as ozone and nitrogen dioxide. Experimentally, the effects of discharge power and frequency on the performance of DBD reactor were studied. Two oxidants, $O_3$ and $NO_2$, were synthesized and used for incinerating soot in the used DPF. Performances of the two oxidants on the reduction of soot were compared, and it was found that $NO_2$ is more effective than $O_3$ for getting rid of soot