• Journal of Biosystems Engineering
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• v.23 no.1
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• pp.13-20
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• 1998

Carbonized rice husk(char from rice husk) can be used to improve soils for planting, seedlings, horiculture, pomiculture and truck gardening. Although it is not a fertilizer in nature, it stimulates the growth of plants. Carbonized rice husk is highly recommended for raising soil/water temperature, keeping moisture and aerating roots of plants. The objective of this study was to develop the effective production method of carbonized rice husks by a non-slagging vertical cyclone combustor. A cyclone combustor w vortex collecor Pocket in addition to central collector pocket was selected and tested. Isothermal tests and mixed firing with LPG and rice husk were performed in order to characterize the system. hut rice husk was used during the isothermal test to find the mass collected of rice husk. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. The composition of original and carbonized rice husks was analyzed by the ultimate analysis. With the air flow rate of 20 ㎥/h, LPG flow rate of 0.45 1/min, the required carbonized rice husk could be obtained.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.3
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• pp.237-247
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• 2009

The combustion characteristics of car components have been investigated, The combustion parameters like heat release rate, smoke production, yield of carbon dioxide and carbon monoxide and mass loss rate were analyzed by cone-calorimeter for representative samples (seat, carpet, headrest, rubber mat, dash board and electric wire) collected from a used car. The results from sample combustion showed that cover and sponge in seat more quickly ignited and flamed than other parts. The heat released from the combustion of dash board sample was 144.29$kw/m^2$ and the smoke produced by the wire combustion was 6896.4 $m^2/m^2$. The yields of carbon dioxide and carbon monoxide were in the ranges of 1.09${\sim}$2.76 kg/kg and 0.0262${\sim}$0.1008 kg/kg, respectively.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.5
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• pp.128-135
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• 1992

Using a commercial flow-analysis code VSAERO, a method to predict the drag of an automobile induced by the intake air of the cooling system has been devised. Given the pressure loss coefficient across the radiator, which varies with the radiator shape and the local Re, a simplified model of the internal flow is coupled with VSAERO to find the mass-flow rate through the car. The flow rate is obtained iteratively and that, in turn, gives the drag associated with this flow, which essentially is the momentum carried by the drained air. The results of a few sample cases are presented for two front-end shapes in combination with varying radiator frontal area.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.234-240
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• 2015

In the face of the world's growing energy storage needs, liquid hydrogen offers a high energy density solution for the storage and transport of energy throughout society. A 5 L liquid hydrogen storage tank has been designed, fabricated and tested to investigate boil-off rate of liquid hydrogen. As the insulation plays a key role on the cryogenic vessels, various insulation methods have been employed. To reduce heat conduction loss, the epoxy resin-based insulation supports G-10 were used. To minimize radiation heat loss, vapor cooled radiation shield, multi-layer insulation, and high vacuum were adopted. Mass flow meter was used to measure boil-off rate of the 5 L cryogenic vessel. A series of performance tests were done for liquid nitrogen and liquid hydrogen to compare with design parameters, resulting in the boil-off rate of 1.7%/day for liquid nitrogen and 16.8%/day for liquid hydrogen at maximum.

• Tuberculosis and Respiratory Diseases
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• v.84 no.1
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• pp.74-83
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• 2021

Background: This study compared the treatment outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) before and after the implementation of public-private mix (PPM). Factors affecting treatment success were also investigated. Methods: Data from culture-confirmed pulmonary MDR-TB patients who commenced MDR-TB treatment at Pusan National University Hospital between January 2003 and December 2017 were retrospectively reviewed. Patients were divided into two groups in terms of PPM status: pre-PPM period, patients who commenced MDR-TB treatment between 2003 and 2010; and post-PPM period, patients treated between 2011 and 2017. Results: A total of 176 patients were included (64 and 112 in the pre- and post-PPM periods, respectively). 36.9% of the patients were resistant to a fluoroquinolone or a second-line injectable drug, or both. The overall treatment success rate was 72.7%. The success rate of post-PPM patients was higher than that of pre-PPM patients (79.5% vs. 60.9%, p=0.008). Also, loss to follow-up was lower in the post-PPM period (5.4% vs. 15.6%, p=0.023). In multivariate regression analysis, age ≥65 years, body mass index ≤18.5 kg/m², previous TB treatment, bilateral lung involvement, and extensively drug-resistant (XDR)- or pre-XDR-TB were associated with poorer treatment outcomes. However, the use of bedaquiline or delamanid for ≥1 month increased the treatment success. Conclusion: The treatment success rate in MDR-TB patients was higher in the post-PPM period than in the pre-PPM period, particularly because of the low rate of loss to follow-up. To ensure comprehensive patient-centered PPM in South Korea, investment and other support must be adequate.

• Journal of Life Science
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• v.18 no.6
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• pp.865-870
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• 2008

The purpose of this study was to examine resting metabolic rate (RMR) and thyroid hormonal (TSH, $T_3$, and $T_4$) changes following weight loss by diet with regular exercise in obese women. The subjects of the present study were 7 women who were above 30% body fat. The subjects arrived into the laboratory in the morning after 12 hour overnight fasting. All subjects measured RMR, % body fat, and fat free mass at weight loss program start time, after 4 weeks and after 8 weeks. All the RMR values were expressed as absolute value (kcal/day), absolute value/FFM (kcal/day/FFM), and absolute value/BSA (kcal/$m^2$/hr), and were calculated predicted RMR value minus actual RMR value. Also, correlation of blood thyroid hormonal (TSH, $T_3$, and $T_4$) secretion and RMR were analyzed. There were significant differences in weight, % body fat, and BSA following diet with exercise (p<0.05). Also, there was a difference between predicted RMR and actual RMR value following weight loss (p<0.05). We also examined the hormonal changes according to weight loss. After weight loss, the level of TSH and $T_4$ were higher than before. But there were no significant differences. Also, the level of $T_3$ was lower than rather before but there was no significant difference. Among the anthropometric factors, FFM was highly correlated (r=0.761) with actual RMR value before weight loss. Also, there was a correlation (r=0.771) with actual RMR value after weight loss. Therefore, actual RMR expressed as FFM increased in weight loss program by diet with exercise. There were no changes in the level of thyroid hormonal TSH and $T_4$.

• KIEAE Journal
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• v.16 no.6
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• pp.167-172
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• 2016

Purpose: The solar water heater with natural circulation has been used for several decades in the world as it is automatically operated without a pump and controller and is easy to maintain and repair. After the subsidy was offered from 2012, the solar water heater with natural circulation is becoming increasingly popular in Korea. Recently, the development of a wall-integrated solar water heater, which improves the applicability of buildings and prevents the overheating in the summer, is being developed. On the other hand, the design and performance evaluation data of solar water heaters are very inadequate, and analysis of heat and flow is required to develop a new type of solar water heater. Method: Therefore, in this study, we proposed a new simplified system analysis model that reflects heat and pressure loss from the test results of KS B ISO 9806-1 (Solar collector test method), assuming that the collector is a simple pipe system, the validity of which was verified through experiments. Result: As a result, first, the RMSE of the system circulation flow rate and the average temperature of the inlet and outlet of the collector according to the experimental results and the simulation are 0.05563 and 0.88530, respectively, which are very consistent. Secondly, the mass flow rate is increased linearly with the increase of the solar radiation, and the mass flow rate is 0.0104 ~ 0.0180kg/s in the range of $200{\sim}380W/m^2$ of solar irradiance. Compared with the test flow rate 0.0764kg / s of the test collector, it showed a level of less than 20%.

• Analytical Science and Technology
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• v.5 no.2
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• pp.169-176
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• 1992

Analytical detection limits and Relative Ion Yield (RIY) by a jet type ion source glow discharge mass spectrometer(GD/MS) have been measured. With a jet type ion source, the sample loss rate for a Cu sample is 0.23 mg/min with 0.1 L/min gas flow rate and 0.11 mg/min with no gas flow rate. However, the ion intensity of Cu does not change significantly with thee variation of the gas flow rate. The RIY values obtained from the calibration curves of the six copper based standards were between 0.57 of Fe and 3.5 of Cr. The detection limits of most elements were in the range of 0.9 and 2.0 ppm when the glow discharge was operated at 4 mA, 1000V.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.3
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• pp.295-305
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• 1996

This study was done to evaluate the effectiveness of dietary calcium level(a diet which met 100% or twice the calcium level in AIN-76 diet) on preventing bone loss in ovariectomized rats. Forty female Sprauge-Dawley rats(body weight 200$\pm$5g) were divided into two groups. One group were ovariectomized(Ovx) while the others received sham operation(Sham). Thereafter, each rat group was further divided into normal calcium diet(NCD, 0.52%) and high calcium diet(HCD, 1.04%) sub-groups. All rats were fed on experimental diet and deionized water ad libitum for 8 weeks. Urinary pyridinoline & creatinine and serum estradiol, luteinizing hormone, calcium, phosphate, total protein, albumin, alkaline phosphatase and osteocalcin were determined. There were no significant differences in serum calcium. total protein and albumin in the two groups(Ovx vs Sham) of rats. Ovariectomized rats had significantly lower estradiol than sham operated rats. There was a highly significant correlation between total bone mineral density(TBMD) and overall level of esteradiol(r=0.59, p<0.05). Total bone mineral density did not correlate significantly with ALP or osteocalcin, although a negative trend was evident. However, the rats fed high calcium diet had a lower crosslinks value and osteocalcine than the rats fed normal calcium diet. An increased rate of bone turnover is usually associated with a decrease in bone mass bexause bone formation at each remodeling site is never as great as resorption. Ovariectomized rats fed high calcium diet had a lower crosslink value and osteocalcin; it means high cacium diet decreased bone turnover rate. The findings from the present study demonstrated that bone loss due to ovarian hormonal deficiency can be partially prevented by a high calcium diet. Futhermore, these findings support the strategy of the use of a high calcium diet in the prevention of estrogen depletion bone loss (postmenopausal osteoporosis).

• Corrosion Science and Technology
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• v.10 no.2
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• pp.52-59
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• 2011

Corrosion of metallic materials occurs by the reaction with corrosive environment such as atmosphere, marine, soil, urban, high temperature etc. In general, reduction of thickness and cracking and degradation are resulted from corrosion. Corrosion in all industrial facilities and infrastructure causes large economic losses as well as a large number of accidents. Economic loss by corrosion has been reported to be nearly 1-6% of GNP or GDP. In order to reduce corrosion damage of industrial facilities, corrosion map as well as a systematic investigation of the loss of corrosion in each industrial sector is needed. The Corrosion Science Society of Korea in collaboration with 15 universities and institutes has started to survey on the cost of corrosion and corrosion map of Korea since 2005. This work presents the results of the survey on cost of corrosion by Uhlig, Hoar, and input-output methods, and the evaluation of atmospheric corrosion rate of carbon steel, weathering steel, galvanized steel, copper, and aluminum in Korea. The total corrosion cost was estimated in terms of the percentage of the GDP of industry sectors and the total GDP of Korea. According to the result of Input/output method, corrosion cost of Korea was calculated as 2.9% to GDP (2005). Time of wetness was shown to be categories 3 to 4 in all exposure areas. A definite seasonal difference was observed in Korea. In summer and fall, time of wetness was higher than in other seasons. Because of short exposure period (12 months), significant corrosion trends depending upon materials and exposure corrosion environments were not revealed even though increased mass loss and decreased corrosion rate by exposure time.