• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.654-661
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• 2000

Area of greenhouse increases rapidly up to 45,265ha by the year of 1998 in Korea. Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat of the oil combusted in the furnace. In order to recapture the heat of this exhaust gas and to recycle for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The exhaust heat recovery system was made for space heating in the greenhouse. The system consisted of a heat exchanger made of heat pipes, ${\emptyset}15.88{\times}600mm$ located in the rectangular box of $600{\times}550{\times}330mm$, a blower and air ducts. The rectangular box was divided by two compartments where hot chamber exposed to exhaust gas in which heat pipes could pick up the heat of exhaust gas, and by evaporation of the heat transfer medium in the pipes it carries the heat to the cold compartment, then the blower moves the heat to greenhouse. The number of heat pipe was 60, calculated considering the heat exchange amount between flue gas and heat transfer capacity of heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/hr depending on the inlet air temperature of 12 to $-12^{circ}C$ respectively when air flow rate $1,100\textrm{m}^3/hr$. The exhaust gas temperature left the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the air and the flue gas, the temperature difference was collected by the air and the warm air temperature was about $60^{circ}C$ at the air flow rate of $1,100\textrm{m}^3/hr$. This heat pipe type exhaust heat recovery system can reduce fuel cost by 10% annually according to the economic analysis.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.67-85
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• 2009

This study aims to provide the research for dental technician's stress prevention and management with basic materials by understanding dental technician's psychosocial stress level and examining relevant factors. The subject of this study is 255 dental technologists who work mainly in Seoul Gyeonggi district for a month of April of 2009 and I conducted cross-sectional study through self administered survey. The contents of survey include general feature, occupational feature, health behavior feature. I used Karasek's Job Content Questionnaire, JCQ and Psychosocial well-being index, PWI-SF as means of measurement. To compare the level of dental technician's psychosocial stress, I conducted t-test and ANOVA and I measured the factors that are related with psychosocial stress symptom with step by step multiple regressive analysis. According to the result of Cronbach's a value which is yielded to verify the reliability of means of measurement, the reliability of concept is sufficient. The detailed result of this study is as follows. 1. According to the result of analyzing the stress symptom in accordance with general feature and occupational feature, those dental technologists who are older and not married, graduate from junior college, have lower position, work at university hospital or general hospital show lower stress(p<0.05). There is no difference in the level of psychosocial stress with regard to duty related feature, period of service, daily average working hours, monthly average pay. 2. With regard to health behavior feature, those dental technologists who control weight better and have meal more regularly show lower stress(p<0.05). Those dental technicians who smoke, drink liquid and take a suitable sleep show low stress but the difference does not have significance statistically. 3. With regard to the factors of stress in the workplace, those dental technicians who have lower duty related requirement, have higher duty related control ability, have higher social support, have less instability of employment and have less workload and physical burden show lower stress(p<0.05). 4. According to the result of analyzing the factors that influence dental technologist's stress symptom, social support has the most enormous influence on stress symptom. Unstable employment, regular exercise, regular eating, daily average sleeping hours and technological capacity are also important in this order. According to the result of this study, those dental technicians who have higher social support, less instability of employment, do exercise more regularly, take enough sleep more soundly and have higher technological capacity show lower psychosocial stress symptom. Therefore, to adjust appropriately the dental technician's stress and properly maintain and improve the dental technician's mental health, effective management plan that enables dental technicians to maintain smooth human relationships for dental technicians should be sought. In addition, heath education and health management for dental technicians should be given more thoroughly so that they can establish desirable health behavior in daily life.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1027-1031
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• 2014

Free cooling system is used to reduce energy consumption of cooling system. Free cooling system is consisted of cooling group and dry-cooler in which heat exchange of chilled water and out air is conducted. Although this system has an excellent energy saving effect in place having cooling load regularly, data or material of design for free cooling system is lacked. In this study, characteristics analysis of free cooling system is conducted through software HYSYS with changing some facts. The main result is following as : Dry-cooler capacity is influenced by out air temperature, required chilled water temperature and LMTD(Logarithmic Mean Temperature Difference) of heat exchanger. As out air temperature is more low, dry-cooler capacity become increased. in addition, as required chilled water temperature is more high and LMTD is more low, the out air temperature range is widened for using dry-cooler. If out air temperature is below $0^{\circ}C$, antifreeze need to be used because freeze and burst can be occurred. In case of South Korea, antifreeze of 34% of ethylene glycol concentration is proper. When compressor load of R22, R134a and R407C is compared, considering environmental regulation and energy consumption, R134a is best working fluid.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.217-222
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• 2010

Bark is a general medium for potted Cymbidium in Korea, but it is difficult to shake off or eliminate the medium from the roots before exporting the potted plants. This working process can injure the roots and then deteriorate plant marketability. This study was carried out to select the optimum medium easier to eliminate from the roots instead of bark and the optimum amount of applied fertilizer to improve the plant growth. Cymbidium young plants 'Honey Hot' and 'Desert Look' were planted in pots with bark, cocochip, and peatmoss. The plants were treated with 2, 4, and 6 g of slow release fertilizer. The plant growth characteristics were investigated in the first and second years during production period of three years. The medium characteristics and mineral nutrient content of the leaves were also examined in the second year. In the first year, the plant growth of 'Desert Look' was improved in all peatmoss treatments more than bark. 'Honey Hot' showed the highest plant growth values in the bark treatment. In the second year, the plant growth of the two cultivars was improved in peatmoss. Cocochip treatments showed the lower plant growth values than bark and peatmoss in the first and second year. There was no significant difference among fertilizer amounts in all the media. The higher CEC values of peatmoss medium resulted to higher capacity to hold more nutrients than bark, and the nutrient retention of the peatmoss improved the plant growth. The higher K and Ca contents in the leaves would contribute to improve the plant growth. Consequently, it would be possible to use peatmoss instead of bark for Cymbidium young plants, but there must be always attention to appropriately water the medium and manage the moisture.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.389-397
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• 2014

An absorption chiller-heater using only a natural refrigerant hardly causes any environmental pollution. In an absorption chiller-heater, the performance of its high-temperature generator, which uses exhaust gases, is essential to achieving superior system performance. To investigate the performance of such a high-temperature generator, a laboratory-scale high-temperature generator working with exhaust gases was designed and tested. Changes in the performance of the high-temperature generator as a function of inlet conditions of the absorbing solution, such as air inlet temperature and mass flow, were investigated. It was observed that when the air mass flow rate ratio was increased from 80% to 120%, the heat capacity was increased by 30%, 33%, 34%, and 37%, respectively. Additionally, when the air inlet temperature was elevated from $170^{\circ}C$ to $210^{\circ}C$ for absorption solution concentrations of 56%, 55%, 545, and 53%, the heat capacity increased by 140%, 160%, 220%, and 224%, respectively.

• Food Science of Animal Resources
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• v.23 no.1
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• pp.21-27
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• 2003

This study was carried out to investigate the effect of curing method(tumbling and immersion) and curing time (10 min to 48 hrs) on pH, color, product yield, cooking yield, water holding capacity, shear force, and sensory evaluation of cured pork meat with soy sauce. Curing method had an effective on color of cured meat(before cooking), Meats were tumbled for 30 min, followed by 24 hr and 48 hr delay period showed higher lightness than meat immersed for 24 and 48 hrs, respectively. Tumbling processing improved product yield and cooking yield as compared to immersion counterpart. Therefore, tumbled meat had significantly greater product yield(p <0.05) during working time for 30 min. Increasing curing time improved water holding capacity and tenderness. Although curing time had no influence on sensory evaluation, tumbling processing improved sensory evaluation of texture, juiciness, and overall acceptability fer cured pork meat with soy sauce, as compared to immersion counterpart.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5423-5433
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• 2013

This study has analyzed the factors related to everyday stress, professional stress, and professional satisfaction experienced while performing administrative duties in unit of school, concerning administrative education government officials. The study period was set from March 10 to March 30, 2013, and the subjects of study was set as 122 employees of Cheongwon-gun, Cheongju-si, Chungcheongbuk-do, working as administrative education government officials. The spsswin18.0 program was used for data analysis, and the t-test, and frequency analysis and credibility were also analyzed. The positive analysis was verified at a significant level of 5%. The results of the analysis displayed regarding the Professional Satisfaction pursuant to demographic Characteristic, the difference of Professional Satisfaction between positions was meaningful. However, the differences between sex, age, religion, educational background, marital status, school level, school scale, career, drinking, smoking were not analyzed as meaningful at a significant level of 5%. With regard to Sub-factors of Professional Satisfaction for Demographic Characteristic, the factors in the part of human resource management, human relation, and job capacity were analyzed as meaningful but organizational atmosphere was analyzed as not meaningful at a significant level of 5%. Also with regard to the stress on Quantitative Role among Sub-factors of Professional Stress by Demographic Characteristic, the difference between age, school level, position, career, smoking was meaningful. With regard to career development, the difference between smoking was meaningful. With regard to the stress on role conflict and ambiguity, the difference for demographic characteristic was analyzed as not meaningful at a significant level of 5%. This study implies that the social environmental consideration is required for administrative education government officials, and it is regarded that consideration is required sequentially to developing job capacity, human relation, organizational atmosphere, rather than to human resource management.

• Korean Journal of Community Nutrition
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• v.19 no.6
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• pp.558-567
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• 2014

Objectives: The purpose of this study was to investigate recognition, dietary attitude and education needs for reducing sodium intakes of dietitian at customized home visiting health service (CHVHS). Methods: The subjects were 75 dietitian at CHVHS. We investigated several variables (recognition, dietary attitude, education needs for reducing sodium intakes) and determined sodium intakes level of subjects as 'low', 'middle' and 'high' by Dish Frequency Questionnaire 25 (DFQ 25). Also, we assessed the differences in recognition, dietary attitude, sodium intake level and education needs by dietitian career period (under 3 yrs vs. over 3 yrs) at CHVHS. Results: In recognition related reducing sodium intake, they showed 'checking a sodium content in nutrition labeling' score 2.5/4.0 and 'perception difference between sodium and salt' score 3.1/4.0. There was no difference in the recognition between under 3yrs' group and over 3yrs' group. In dietary attitude related reducing sodium intake, they showed 'palatability for salty taste' score 0.8/1.0, 'attitude in related soups' 0.7/1.0, 'attitude in related using natural spice' 0.6/1.0. There was a difference in 'attitude in related soups' between under 3yrs' group and over 3yrs' group (0.6 vs. 0.7). In sodium intake level by DFQ 25, they showed 'low group' 41.3%, 'middle group' 41.3% and 'high group' 17.3%. There was no difference in the distribution of sodium intake level by the career. In education needs related reducing sodium intakes, there were 'teaching experience' 93.3%, 'have a difficulty in teaching about reducing sodium intakes' 86.6%, and 'necessity of education for CHVHS dietitians' 100.0%. 'Needed education contents for CHVHS dietitians' were ranked as 'cooking way to reduce sodium intake' 58.7%, 'relation between hypertension and sodium' 17.3%, 'composing way to reduce sodium intake' 17.3%. There was a difference in needed education contents 'relationship between hypertension and sodium' (33.3% vs. 2.6%) and 'The cooking way to reduce sodium intake' (38.9% vs. 76.9%) by the career. Conclusions: The results suggested that a capacity training program for reducing sodium intake may be needed for dietitians at CHVHS to improve health of the community elderly. For effective training program related reducing sodium intake for dietitians at CHVHS, it may be necessary to consider the career period as dietitians at CHVHS.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.292-303
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• 2011

A new type of sand bypassing system is proposed for recovering the eroded beach in this study. This system provides an added methodology to the soft defence which is main recovery method for the coastal shore protection in the world. The study proposes a conceptional design and manufacturing procedure for the relatively small size machine of sand bypassing. In order to get the discharging volume information, the power capacity of the system is tested in the field. The discharge rate of the new system shows up to the expected maximum of 618 ton/hr which is 9.6% lower than that by theoretical calculation. It gives a resonable agreement in this system when the flow is assumed to be of the high density. In this study, the delivering volume of sand is estimated according to the discharge rate. The combination of 300 mm(12 inch) intake and 250 mm(10 inch) discharge pipe line has the pumping capacity of $103\;m^3/hr$ which is nearly the same as that of South Lake Worth Inlet sand bypassing system, Florida, U.S.A.. The proposed system added the mobility to its merit. The unit price of Florida's sand bypassing is $$8~9/m^3$ (US). The system would be economically suitable for small volume of sand because no additional equipment is necessary for the intake. The diesel fuel of 25~30 l/hr was consumed during the system operation. The multiple working system would be the next investigation target for large volume of sand.

• The Korean Journal of Emergency Medical Services
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• v.12 no.3
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• pp.115-127
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• 2008

Purpose : This study aimed to examine the effects of empowerment of the paramedics on critical thinking and provide the basic materials for the qualitative improvement of emergency medical service. Methods : This study collected data with the paramedics working at general hospital and hospital emergency room in G metropolitan city, B metropolitan city, U metropolitan city, D metropolitan city and J province from July 1 to 31, 2008. Total 180 questionnaires were collected and 152 were used for final analysis, and the following results were obtained through statistical analysis using SPSS 12.0 program. Results : 1) Average score of empowerment was 4.44 out of 6 and according to average score by areas, significance was 4.94, capacity 4.92, self-determination 4.28, and effective-ness 3.62. 2) Empowerment by general characteristics was statistically significant in age (F = 3.313, p < 0.05), the final scholastic attainments(F = 2.436, p < 0.05), and salary(F = 1.695, p < 0.01). 3) Average score of critical thinking was 3.12 out of 7 and according to scores by areas, maturity was highest as 3.71, followed by no prejudice as 3.70, systemicity as 3.14, pursuit of truth as 3.05, much curiosity as 2.93, critical thinking and self-confidence as 2.92, and analysis as 2.91. 4) Critical thinking by general characteristics was statistically significant in marital status (F = 15.695, p < 0.01) and the final scholastic attainments (F = 2.606, p < 0.05). 5) Correlations between empowerment and critical thinking showed positive correlations as Pearson's correlation coefficient r = 0.400 and positive correlation in all areas including empowerment and critical thinking were found (r = 0.116-0.710). 6) The effect of empowerment on critical thinking was statistically significant in p < 0.01 and was explained as $R^2=0.155$. In the effects of empowerment on critical thinking, significance, capacity and self-determination were statistically significant in p < 0.01, effectiveness in p < 0.05 and were explained as R2 = 0.244. Conclusion : From the above results, it was found that empowerment had the influence on critical thinking, so it was considered that hospital managers and emergency room chiefs must develop and operate education and training program based on the concept of empowerment, maintenance and management strategies.