• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제8권1호
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• pp.7-12
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• 2002

The air ventilation system of operation rooms has been studied to prevent the cross infection during the operation. Operation rooms and air ventilation systems of three University hospitals were investigated. The distribution of microbe was measured by cultivating air samples in the operation room. A two-dimensional model for the cross-section of an operation room was developed for the CFD(Computational Fluid Dynamics) analysis. The characteristics of air flow in the empty operation room and in occupied operation room were calculated by using a CFD program. The current diffuser location of an old hospital did not deliver the clean air to the operation part efficiently. A new method to locate diffusers that improve air venting with little increase of the cost of equipment was suggested.

• International Journal of Precision Engineering and Manufacturing
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• 제7권3호
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• pp.14-17
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• 2006

To diagnosis abnormal compressor conditions in an air-conditioner, the acoustic emission (AE) signal, which is derived from wear condition, compressed air, and assembly error, was analyzed experimentally. Burst and continuous type AE signals resulted from metal contact and compressed air, and the raw AE signal of compressors was acquired in the production line. After extracting samples using waveforms, the Early Life Test (ELT) was conducted and the waveform was classified as normal or abnormal. Efficient parameters in the waveform pattern were investigated in time and frequency domains and a diagnosis algorithm for air-conditioners using Neural Network estimation is suggested.

• 한국대기환경학회지
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• 제11권4호
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• pp.339-349
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• 1995

The purpose on this study is to optimize the chromatographic determination method of trace aldehydes in ambient air. Carbonyl compounds in urban air were trapped at $C_{18}$ DNPH-coated cartridges, and generated hydrazone derivatives were separated by HPLC and detected by UV-vis spectroscopic detector at 360nm. Formaldehyde and acetaldehyde compounds could be isolated from urban(Seoul) air with more than 95% collection efficiency. The analytical detection limits for formaldehyde and acetaldehyde are 0.06pp $b_{v}$, 0.08pp $b_{v}$ for 108 L air samples, respectively. The precision of this method are 3 .sim. 4%(RSD) for mutiple injection of hydrazone standards. Separation of seven dinitrophenylhydrazones could be achieved in appoximately 20 minutes operation time using $C_{18}$ column with apprepriate eluent. The method was applied to the analysis of aldehydes and ketone in Seoul ambient air. The 24-h ambient levels of formaldehyde, acetaldehyde reached up to 6 .sim. 14 and 3 .sim. 8ppbv, respectively. The daily average concentration ratio were 0.60 for acetaldehyde/formaldehyde.yde.

• 지질공학
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• 제34권1호
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• pp.137-146
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• 2024

우리나라의 한국산업표준(KS F)에는 105 ± 5℃로 노건조된 암석을 대기중에 꺼내어 저울에 무게를 측정하도록 하고 있다. 그러나 건조로 외부의 대기에 노출된 암석에서는 대기중의 수분을 흡수하여 무게가 증가하는 문제가 발생된다. 본 연구에서는 정육면체 모양으로 가공된 크기가 다른 8개의 황등화강암 시편을 사용하여 측정 방법에 따른 건조무게를 측정하고 비교 분석하였다. 대기중에서 측정된 특이점의 건조무게는 건조로 속에서 측정된 건조무게에 비하여 더 작게 나타났다. 건조 방법에 따른 건조무게의 차이는 암석의 크기와 양(+)의 상관관계를 나타내었고, 암석의 단위무게당 건조무게 차이는 암석의 크기가 클수록 오히려 작아지는 음(-)의 상관관계를 나타내었다. 대기중 노출된 암석의 무게는 가열된 암석 주위에서 발생되는 대류의 영향과 대기중 수분 흡수로 인한 영향의 크기에 따라 결정되며, 특이점은 두가지 영향의 크기가 같을 때 발생된다. 암석의 크기가 클수록 특이점 발생까지의 시간이 더 오래 걸리고 무게의 감소량도 증가되었다. 또한, 수분 흡수에 의한 초기 측정 무게까지 회복되는 시간도 더 오래 걸렸다. 향후, 특이점의 무게와 건조로 내부에서 측정된 건조 무게에 관한 연구를 통하여 현재 한국산업표준(KS F) 시험규정의 한계점을 보완할 수 있을 것이다.

• 동아시아식생활학회지
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• 제16권3호
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• pp.323-331
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• 2006

The manufacture and consumption of traditional Korean rice cake is being revived due to the introduction of various desserts and confectionaries in the food industry. In order to develop this traditional food of Korea and allow various types of rice cakes to enter the market, it is essential to standardize the cooking methodology. In particular, there has been little research on Dutubpyun, a traditional food famous for its good taste. In addition, the original cooking methodology varies between cookbooks. Therefore, in order to standardize the cooking methodology for Dutubpyun referring to various cookbooks, different types Dutubpyun were made by varying the grain fineness of the glutinous rice powder to 16, 20, 30 and 40 meshes, adding up water to 10%, up sugar to 10% and up soy sauce to 5%. Subsequently, a sensory evaluation, and a test on the moisture, degree of gelatinization and hardness during storage were measured to determine the optimal grain fineness of the powder. For the sensory evaluation, where the grain sizes of the glutinous rice powder were different, the 30 and 40 mesh samples received high scores for grain fineness, moisture and chewiness. The 40 mesh samples received high scores for softness, while the overall quality was the highest in the 30 mesh samples. The moisture content during storage was $38.0{\sim}40.6%$ for the samples on the day of cooking, while it was reduced to $33.3{\sim}35%$ after 3 days of storage. Regarding the degree of gelatinization during storage, the maltose content was $2.4{\sim}2.7 mg$ for the samples on the day of cooking. After 3 days, the maltose content was $2.3{\sim}2.8 mg$ but the maltose content was higher in the 40 mesh samples than in the other samples. Regarding the change in hardness during storage, the hardness marked high in the 20 mesh samples on the day of cooking (p<0.05), while it was high in the 16 mesh samples after 3 days of storage (p<0.001). The hardness tended to increase with increasing storage time. Regarding the surface structure of the glutinous rice powder and Dutubpyun, a difference in grain fineness was clearly seen in the 15x-magnifications photograph of the rice powder structure taken by SEM. At 60x and 180x magnifications of surface of Dutubpyun, the 16 mesh samples had a uniform air gap, and a lumpy configuration. Smaller air gaps were dispersed homogeneously and similar to a net in the 20 and 30 mesh samples. The 40 mesh samples showed to a net-likes structure with cracks. Overall, for the best conditions for cooking Dutubpyun, the grain fineness of the glutinous rice power needs to be 30 mesh.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.555-556
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• 2006

The study examines hardness pattern of SH737-2Cu-.9C samples transient liquid phase sintered at different temperatures viz. $1120^{\circ}C$, $1180^{\circ}C$ and $1250^{\circ}C$, heat treated by various methods and then tempered at different temperatures. Sintered samples were characterized for density and densification parameter, and austenitized at $900^{\circ}C$, subsequently cooled by four different methods viz. annealing, normalizing, oil and brine quenching. Hardness pattern was found minimum for air cooled and maximum for brine quenched, and samples sintered at $1250^{\circ}C$ had relatively higher hardness. The O.Q and B.Q samples were then tempered at $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$ and $700^{\circ}C$. Hardness pattern typically showed secondary hardness taking place, with maximum around $600^{\circ}C$.

• 한국의류산업학회지
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• 제3권5호
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• pp.466-472
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• 2001

To find a suitable condition in this process examined, we investigated the main control factors, such as, the NaOH concentrations, such as, the NaOH concentrations, the heat treating times, and the heating temperatures. The resulting mechanical properties of the fabrics also studied. The samples used were Nylon/Co-PET sea-island type composite microfiber (Co-PET content: 35%) non-woven fabric. The conclusions obtained were as follows. 1. For the complete extraction of Co-PET from the sample non-woven fabric in the dry hot air process, $160^{\circ}C$ of air temperature, 15 min. of treatment time, and around 30% of NaOH concentration were required. On the other hand, in the wet hot air process, $140^{\circ}C$ of air temperature, 3.5 min. of treatment time, and around 30% of NaOH concentration were required. 2. The mechanical properties of the continuous processed samples showed that the WT, B, and WC increased with increasing the weight reduction ratio. However, the G, decreased with increasing the weight loss ratio. Note that, particularly in B, it increased drastically when the weight deduction ratios exceeded 30%. 3. As increasing the wet hot air temperature from 130 to $140^{\circ}C$, B appeared to increase, however, WT, G, and WC appeared to decrease. 4. The best condition found in this continuous process to extract Co-PET is the wet hot air temperature of 140, NaOH concentration of 28% or above, and the treatment time 2-4 min.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.561-575
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• 1994

Williams, M K., King, E., and Walford, Joan (1969). Brit. J. industr. Med., 26, 202-216. An investigation of lead absorption in an electric accumulator factory with the use of personal samplers. Thirty-nine lead workers and controls, in stable conditions of exposure, each wore personal lead-in-air samplers daily for two weeks. During the second week samples for blood lead, urinary lead, urinary coproporphyrin, urinary $\gamma$-aminolevulinic acid (ALA), the punctate basophil count, and haemoglobin were taken daily. Duplicate estimations were made on one day. The lead exposures of men doing almost identical jobs differed by ratios of up to four to one. This could be attributed on y to personal differences in working habits. The correlation coefficients and regression equations of the biochemical tests with lead-in-air and with each other were determined. The mean values and $95\%$ confidence limits of single determinations of some of the biochemical tests corresponding to the two commonly accepted TLVs of lead-in-air (0-20 and 0-15 mg./$m^{3}$) were calculated from the regression equations. For each biochemical test the variation due to analytical error, the variation from day to day within subjects and the residual variation about the regression on lead-in-air were calculated. Previous estimates of the latter are not known. Excessive confidence may be placed in an index of exposure due to its low coefficient of variation within subjects unless the coefficient of variation between subjects about regression is taken into account. The correction for specific gravity of estimations of lead and ALA in spot samples of urine was found to reduce slightly the residual variation between subjects about the regression on lead-in-air and to increase the correlations with lead-in-air and with the other biochemical tests, but these changes were not statistically significant. The modified method used for estimating blood lead and urinary lead is described and validated.

• 한국물환경학회지
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• 제24권1호
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• pp.19-29
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• 2008

Hot air sparging is a groundwater remediation technique, in which organic contaminants volatilized into hot air from the saturated to vadose zone. In the laboratory diesel (10,000 mg TPH/kg) was spiked in contaminated saturated aquifer soil. The hot air ($34.9{\pm}2.7^{\circ}C$) was injected in intermittent (Q=1,500 mL/min, 10 minute injection and 10 minute idle) modes. We performed microcosm tests using the groundwater samples to assess TPH reductive remediation activity. For Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of eubacterial communities in sludge of wastewater treatment plants and soil of experiment site, the 16S rDNA was amplified by Polymerase Chain Reaction (PCR) from the sludge and the soil. The obtained 16S rDNA fragments were digested with Msp I and separated by electrophoresis gel. We found various sequence types for hot air sparging experiment with sludge soil samples that were closely related to Bacillus (149 bp, Firmicutes), Methlobacterium (149 bp, Euryarchaeotes), Pseudomonas (492 bp, ${\gamma}$-Proteobacteria), etc., in the clone library. In this study we find that TPH-water was reduced to 78.9% of the initial value in this experiment aquifer. The results of the present study suggests that T-RFLP method may be applied as a useful tool for the monitoring in the TPH contaminated soil fate of microorganisms in natural microbial community.

• 한국식품영양학회지
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• 제35권6호
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• pp.426-434
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• 2022

In this study, the effect of osmotic drying conditions of mangoes on hot air drying was investigated. Four different osmotic agents of 60 Brix, such as S60, SM10, HF80, and SG25, were prepared. Mango slabs were osmotically dried with the agents at a ratio of 1:4 (w/w) for up to 8 hours. SG25 showed the lowest weight reduction and moisture loss during the process. As a result of hot-air drying, all samples showed a high correlation with the Page model (0.9761~0.9997), and the required drying time of all samples that were osmotically dried was reduced compared to the non-osmotically dried group. After hot-air drying, the pH value increased according to the drying temperature. The L, a, and b values and the total polyphenol content also decreased. Through this study, the possibility of osmotic drying was confirmed to increase the efficiency of hot air drying of mangoes, which is expected to contribute to the industrial use of domestic mangoes.