• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.90-96
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• 2008

In order to meet the stringent requirement of sludge disposal and to find ecological alternative, aerobic digestion coupled with alkaline pretreatment was studied. The treated sludge was tested for the potential of liquid fertilizer. In the aerobic digestion, it was obvious that the performance of digester B(fed with the sludge pretreated by NaOH) was better than that of digester A(fed with raw sludge) in terms of COD and SS removal. SS and VSS removal rates in digester B were 66% and 69%, respectively. At 5 days, TSS removal rate reached 47% in the digester B, which was 71% of final TSS removal rate. It revealed that the pretreatment process can shorten the retention time of aerobic digestion. 94.1% of TCOD in the raw sludge was reduced by alkaline pretreatment and aerobic digestion. Final SCOD was in the range of 220$\sim$230 mg/L implying the sludge was stabilized. Nitrification and pH drop were observed in the aerobic digestion. Final nitrate concentrations in digester A and B were 445.4 and 223.1 mg/L and final pH in digester B was 3.0. Biological assays reported that leaf size of cucumber seedling increased with nitrate concentration and sludge to soil ratio. The sludge treated by alkaline and aerobic digestion promoted the growth of seedling leaf and stem remarkably compared to raw sludge. In contrast, the aerobically digested sludge without pretreatment improved leaf growth and inhibited stem growth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.1-7
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• 2018

The gases emitted from internal combustion engines using fossil fuels are causing many social problems, such as environmental pollution, global warming, and adverse health effects on the human body. In recent years, the demand for renewable energy has increased, and government policy support and research and development are also active. In the collecting part of a solar energy system, which is widely used at home, propylene glycol (PG) (anti-freeze), as a heating medium, is mixed with water at a fixed value of 50%, and the heat is transferred to the collecting part at subzero temperatures. On the other hand, when leakage occurs in the heat medium in the heat collecting part, supplemental water is supplied to the solar heat collecting part due to the characteristics of the solar heat system, so that the concentration of antifreeze in the replenishing water becomes low. As a result, the temperature of the solar heat collecting part is lowered resulting in a frost wave, which causes economic damage. The purpose of this study was to develop a device capable of controlling the antifreeze concentration automatically in response to a temperature drop to prevent freezing of the heat collecting part generated in the solar energy system. The electrical conductivity of the H2O component was larger than that of PG, and the resistance increased with decreasing temperature. The PG concentration control values of 40, 50, and 60% should be controlled through calibration with a PG concentration of 39.6, 50.7, and 60.1%.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.219-225
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• 2014

In this study, effect of cosurfactant on the solubilization rate of n-octane, n-decane and n-dodecane oil was performed by micellar solutions of polymeric nonionic surfactant Pluronic L64($EO_{13}PO_{30}EO_{13}$) at room temperature. It has been found that the solubilization rate of a hydrocarbon oil was enhanced with an increase in both chain length and amount of alcohol added. In case of addition of a short chain alcohol such as 1-butanol, the solubilization rate of a hydrocarbon oil was slightly increased since most of alcohol molecules remained in an aqueous surfactant solution. On the other hand, the addition of a relatively long chain alcohol such as 1-hexanol and 1-octanol produced a big increase in solubilization rate of a hydrocarbon oil mainly due to incorporation of alcohol molecules into micelles and thus producing more flexible micellar packing density. Dynamic interfacial tension measurements showed the same trend found in solubilization rate measurement. Both interfacial tension value at equilibrium and time required to reach equilibrium decreased with an increase in chain length of an alcohol.

• KSBB Journal
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• v.16 no.6
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• pp.603-608
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• 2001

In this study, we studied on the remeval of toluene vapors in a lab-scale biofilter. Biofiltration was performed in a column fed downflow with contaminated air at ambient conditions. The column was packed with mixture of Peat and Calstene(5:3 vol. Ratio), Synthesized media, Bark and Wood chip, which were inoculated with microbial population of selected stains(Pseudomonas. putida, KCCM 11343, ATCC 12633). The microorganisms were immobilized on the bed medium and then biofilm were formed. The biofilter was operated under the conditions of various inlet toluene concentrations for 180 days and treated up to the elimination capacity of maximum 40 g/㎥hr at the inlet load of 30 g/㎥ hr with percentage removals of 20∼90% and gas retention times between 1 and 2 min. The pressure drop was very negligible through the biofilter columps because its value of 0.054 cmH$_2$O/m was much less than others. The effect of operating conditions such as flow rate, inlet toluene concentration and moisture contents on the performance of the biofilter was sequentially investigated in this study.

• Journal of the Korea Fashion and Costume Design Association
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• v.16 no.3
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• pp.201-217
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• 2014

There is likely to be a fit problem when women aged in their 30s-40s purchase down-age clothing from brands that target women in their 20s. To identify the part of the lower body that causes the fit problem, the sizes and types of lower body of women in their 30s-40s were compared with those of women in their 20s. The data for this study was from the 2010 Size Korea survey of body measurements of 1675 female adults in their 20s-40s. To examine differences in the average sizes of the lower body between women in their 20s and 30s-40s, descriptive statistics and t-tests were conducted. Factor and cluster analysis were used to classify body types by age groups. On the whole, compared to women in their 30s-40s, women in their 20s were found to be higher for all height items and smaller for size, thickness and width items. The result of the Glycemic index analysis showed that the body type of women in their 20s was generally larger than that of women in their 30s-40s. In addition, women in their 20s had a large drop value compared to those in their 30s-40s, whereas flatness of body cross section was bigger in the group of women in their 30s-40s. Four factors related to the lower body type of female adults in their 20s-40s were identified in the factor analysis, and three categories of body type were identified by cluster analysis. A Type 1 individual had abdominal obesity and chubby lower limbs, Type 2 had short legs and slightly chubby lower limbs, and Type 3 had long legs and a skinny lower body. A significant number of women in their 30s-40s were included in the Type 1 group, which was the least common category for women in their 20s.

• Journal of Technologic Dentistry
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• v.36 no.2
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• pp.83-89
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• 2014

Purpose: This study is to evaluate the effect of modeling liquid on the shear-bond strength between zirconia core and veneering ceramic. Methods: Disk-shaped (diameter: 12.0mm; height: 3.0mm) zirconia were randomly divided into six groups according to the surface conditioning method and whether modeling liquid is used or not to be applied (N=60, n=10 per group): group 1-control group with distilled water(ZD); group 2-control group with modeling liquid(ZM); group 3-airborne particle abrasion with $110-{\mu}m$ $Al_2O_3$(AD) with distilled water; group 4-airborne particle abrasion with $110-{\mu}m$ $Al_2O_3$ with modeling liquid(AM); group 5-liner with distilled water(LD); group $6{\pounds}{\neq}liner$ with modeling liquid(LM). Contact angles were determined by the sessile drop method at room temperature using a contact angle measurement apparatus. The specimens were prepared using dentin veneering ceramics, veneered, 3mm high and 2.8mm in diameter, over the cores. The shear bond strength test was performed in a Shear bond test machine. Load was applied at a cross-head speed of 0.50mm/min until failure. The fractured zirconia surfaces were evaluated by using stereomicroscope (${\times}30$). Collected data were analyzed using SPSS(Statistical Package for Social Sciences) Win 12.0 statistics program. Results: ZD showed the highest contact angle($50.6{\pm}5.4^{\circ}$) and LD showed the lowest value($6.7{\pm}1.3^{\circ}$). Control groups and zirconia liner groups were significantly higher contact angle than liner groups(p<0.05). LD was the highest shear bond strength($43.9{\pm}3.8MPa$) and ZD was the lowest shear bond strength($24.8{\pm}4.9MPa$). Shear bond strengths of control groups and contact angle of liner groups were not significantly different((p>0.05). Liner groups presented adhesive failures. The others groups showed cohesive and adhesive failures. Conclusion: Modeling liquid groups showed lower contact angles and lower shear bond strength compared to those of distilled water groups.

• Korean journal of food and cookery science
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• v.13 no.5
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• pp.592-601
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• 1997

The purposes of this study were to develop Hazard Analysis Critical Control Point-based standardized recipe applicable to cook/chilled soy sauceglazed mackerel and to evaluate the qualities related to the product flow of this item. After conducting experimental cooking, preliminary test, and analysis of recipes, critical control points were identified, control methods were determined, and HACCP-based recipe was standardized. At each critical control point, time-temperature profile was recorded and microbiological analysis (total aerobic plate counts, psychrotrophic plate count, coliform, and fecal coliform count), chemical analysis (pH, acid value and volatile based nitrogen (VBN)) and sensory evaluation of the item were done. Time-temperature data showed that the time the menu item had passed through temperature danger zone (5∼60$^{\circ}C$) during all phases was 60 min. At rapid cooling, but after cooling at room temperature, the temperature of this menu item did not drop below the ambient temperature. The results of microbiological test were negative throughout all phases following cooking and the results of chemical analysis did not change significantly in terms of storage periods except for VBN which increased on 7th day significantly(p<0.05). After steam/convection oven reheating and microwave oven reheating, the sensory score of the only appearance decreased significantly related to the storage time of overall quality profiles. But significant differences were not detected according to two reheating methods. In conclusion, this HACCP-based recipe was considered as an effective tool for assuring microbial as well as sensory quality of this cook/chilled item.

• Fire Science and Engineering
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• v.26 no.2
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• pp.1-10
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• 2012

While a performance based sprinkler design method has been widely used in UK and USA according to fire hazards of occupancies, Korean fire safety industry could not yet accept it due to nonstandardization on risk level of various occupancy. Even only two or three spray pattern sprinkler was produced in Korea fire safety industry, therefore, various spray pattern sprinklers have not yet introduced to major occupancies. Spray pattern sprinklers with one of two K value have been used in all occupancies in Korea Market. UK and USA's Fire industry should produced the spray sprinklers with various K-factors and protection area due to performance based sprinkler design requirement. Therefore the fire load density for main occupancies has been investigated in order to compare with installation standard in advanced countries. Eventually a lot of variations in orifice and K factors of standard heads were set up including special heads needed for high hazard areas such as large drop type, enlarged orifice type and early suppression fast response.

• Korean Journal of Clinical Pharmacy
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• v.28 no.3
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• pp.167-173
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• 2018

Background: In July 2016, the Infectious diseases society of america and the american thoracic society (IDSA & ATS) published a guideline recommending piperacillin/tazobactam (Pip/Tazo) 18 g/day as the anti-pseudomonal dose for the treatment of pathogenic pneumonia. After the guideline was published, the Pip/Tazo dose used for the treatment of pathogenic pneumonia was changed from 13.5 g/day to 18 g/day in a superior general hospital intensive care unit (ICU). In this study, we analyzed the effectiveness and safety of the new dose. Methods: Adult patients aged ${\geq}19years$ who were diagnosed with pneumonia in ICU and who received Pip/Tazo for 7 days or more from September 1, 2015 to May 31, 2017 were included in the study. The electronic medical record (EMR) was retrospectively analyzed. Results: At baseline, there was a significant difference between 44 patients treated with 13.5 g/day and 31 patients treated with 18 g/day of Pip/Tazo. The 18 g/day-treatment group comprised more elderly patients than the 13.5 g/day-treatment group (p=0.028). The results of the treatment-effects analysis showed no significant difference between the two groups. In case of safety data, there were significant differences in two parameters related to blood count, namely hemoglobin (p=0.016) and platelet count (p=0.011). Conclusion: Based on the significant difference in baseline age, there is a possibility that high-dose Pip/Tazo showed improved therapeutic effect. However, when high-dose Pip/Tazo was used, the blood cell count was found to drop from the reference value more frequently. Therefore, blood cell count should be monitored carefully when high-dose Pip/Tazo is administered.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.2
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• pp.69-76
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• 2010

This paper proposed a new fast multi-reference frame motion estimation algorithm. The proposed algorithm reduces search areas of motion estimation using a linear relation of motion vector with distance of each reference frame. New algorithm executes full search area motion estimation in reference frame 0 and reference frame 1. After that, search areas in reference frame 2, reference frame 3 and reference frame 4 are minimized by distance of each reference frame and results of motion estimation in reference frame 0 and reference frame 1. The proposed algorithm does not use a threshold value which is obstacle of hardware implementation and processing time schedule. Also, it reduced computation quantity of multi-reference motion estimation. Hardware implementation of multi-reference frame motion estimation is possible by these features. Simulation results show that PSNR drop and bitrate increase of proposed algorithm are lower than those of previous fast multi-reference frame motion estimation algorithm The number of computation of new algorithm is reduced 52.5% and quality of result is negligible when compared with full search area motion estimation which has 5 reference frames.