• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.87-93
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• 2003

A survey including an inspection was conducted to assess the sanitary condition of kitchens in the school food-service programs and to prepare background data for improving the safety of school meals. The survey was carried out over a two-month period (September-October, 2001). A self-administered questionnaire recommended by the Korea Ministry of Education & Human Resources Development (MOEHRD) was offered to a random sample of dieticians of twenty-five elementary schools in one region of Korea about food, sanitation, and safety inspection of their kitchens. Air temperature, relative humidity, and airborne microbes in the kitchens were monitored during preparation, cooking, and service. The inspection results showed their sanitary rendition met the level B of the recommendation of the Korea MOEHRD. The range of air temperature of the kitchens was 21.4~22.4$^{\circ}C$. and the range of relative humidity was 62.4~69.6%. The microbiological evaluation of kitchen samples indicated aerobic plate count levels from 22..5 to 26.5 CFU/15 minutes. Although the results of inspection show that the levels of sanitary condition of kitchens in the schools were good, they are not satisfactory for safe food-servile because the temperature and humidity levels are high. This study indicates that the school kitchens should be monitored and strict inspection is necessary. The legal standards for school food-service should include standards for kitchen air temperature, relative humidity, and airborne microbes.

• Journal of the Korean Geographical Society
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• v.39 no.1
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• pp.13-26
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• 2004

This paper examined the possibility of NET application for a relative weather stress index in Korea. The characteristic of NET distribution used temperature, relative humidity, wind speed which forecasting at Korean Meteorological Administration were analyzed. Regional critical values of daily maximum NET of stress index for summer resembled the distribution of daily maximum temperature because were not impacted wind and humidity but temperature. Regional critical values of daily minimum NET of stress index for winter distributed variously compared with summer. The highland region and the northern region of Seoul were impacted of low temperature and coastal region which strong wind. The occurrences of stressful days did not vary in summer, but obviously increased in winter after mid-1990s.

• Journal of Biosystems Engineering
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• v.31 no.5 s.118
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• pp.410-415
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• 2006

This study was performed to develop thin layer drying equations for green rice. Thin layer drying tests of green rice were conducted at three temperature levels of 30, 40, $50^{\circ}C$ and two relative humidity levels of 30, 50% respectively. The measured moisture ratio were fitted to the selected four drying models (Page, Thompson, Simplified diffusion and Lewis model) using stepwise multiple regression analysis. The overall drying rate increased as the drying air temperature and as relative humidity was increased, but the effect of temperature increase was dominant. Half response time (Moisture ratio=0.5) of drying was affected by both drying temperature and relative humidity Drying rate was mainly affected by relative humidity at drying temperature of $50^{\circ}C$. The results of comparing coefficients of determination and root mean square error of moisture ratio for four drying models showed the Page model was found to ft adequately to all drying test data.

• Journal of the Korea Furniture Society
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• v.20 no.6
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• pp.599-604
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• 2009

For the search of unified law of moisture movement in wood, moisture distribution of Korean red pine at non-steady state was investigated. We assume that the equilibrium moisture content (EMC) in wood depends on only temperature and relative humidity, it can be control in temperature and humidity chamber. If temperature is constant and humidity or vapor pressure is changed with sin curve shape at adequate cycles, EMC in chamber can be changed as well with sin-curve shape. The setup condition of a non-steady state in humidity control chambers is a constant temperature at $20^{\circ}C$ and 15+10 sin ${\omega}t$ percent EMC. It can be found that the distribution of moisture in the specimen with varying relative humidity are illustrated various types. Moisture in wood is complicated and vibrates with the moisture sorption process. Considering a unified law of moisture movement in wood, it is considered that the most important fact is to search the method of precise diffusion & transfer coefficients.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.53-57
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• 2002

The growth and multiplication of Aspergillus flavus Link and A. tamarii Kita were observed in vitro under variable temperatures of $22-31^{\circ}C$. The matte weight of mycelium and number of conidia/ml were significantly higher (P < 0.01) at the higher temperature than the lower temperature in both the species of Aspergillus. In vivo the mortality in silkworm, Bombyx mori L. with the infection of Aspergillus species was significantly (P < 0.01) different at different temperature and relative humidity conditions.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.358-368
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• 1994

Major factors in reducing the stacking strength of corrugated fiberboard boxes in cold storage or transport conditions are high relative humidity, causing elevated moisture absorption by the boxes. The bottom boxes in a stack will deform to the critical deflection causing agricultural products damage there, and eventually additional deflection will cause box collapse and finally toppling of the stack. The study was conducted to determine the water absorption characteristics and the compressive strength of the corrugated fiberboard boxes being widely used in packaging agricultural products in Korea. The sample boxes for the study were selected from the regular slotted containers (RSC) types, and one was the box used in apple packaging (Box A), another one was the box used in pear packaging (Box B). The corrugated shipping containers were made from a large portion of recycled fibers in Korea, and comparing with Box B, Box A was fabricated from fiberboard which contained more percentage of old corrugated containers (OCC) imported from foreign countries than domestic waste paper. The results obtained from the study were summarized as follows ; 1. Equilibrium moisture content (EMC) of the sample boxes was established after about 20 hours, and the EMC by absorption was lower than that by desorption. The EMC increased with the increasing of relative humidity and with the decreasing of temperature, and the rate of increasing was much higher above the relative humidity of 50%. 2. The maximum compressive strength of Box A was about 100 kgf greater than that of Box B on the same enviromental conditions. The strength of the sample boxes decreased rapidly with the increasing of relative humidity. The effect of relative humidity on the strength was a little higher than that of temperature. 3. As the applied load was progressively increased and a level was reached, the vertical side panels ($L{\times}D$) deflected laterally inwards or outwards. The panels deflected laterally inwards at higher relative humidity. 4. The maximum compressive deflection ratio and the critical deflection ratio of the sample boxes were increased linearly with the increasing of relative hunidity, but trends for its ratios showed inconsistant response to temperature.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.41-48
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• 2003

Most of people spends their times in indoor about 85% of a day. Thus, indoor is more serious than outdoor concerned with the health. We discussed comfortableness in a railroad electric rolling stock, and focused on temperature and humidity. Electric rolling stock is one of major public transportation system because of an increasing in population and heavy traffic problems. The passengers are under the influence of indoor air quality such as air temperature, relative humidity and air velocity. Ventilation system in electric rolling stock should be designed for the health and comfort. One of the main aims is to create an acceptable thermal environment without draught problem. The draught sensation increases when the air temperature decreases and the air velocity increases. Airflow in electric rolling stork is turbulent. Temperature and humidity gradients in electric rolling stock have been studied. And, the difference between mean temperature and rotative humidity measured at 0.7, 0.9, 1.2, 1.7m above the floor. It has been found that temperature and relative humidity with large fluctuations caused more draught complaints.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.184-194
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• 2011

This study is to analyze the internal temperature and relative humidity of concrete at early age, as well as the mechanical behavior. Three different levels of cement unit content were cosidered as an experimental variable. In order to measure internal temperature and relative humidity immediately after concrete placement, this study developed a unique measuring device, which provided reliable results. Different cement content did not significantly affected the strengths including compressive, tensile and flexural strength and after 7 days of curing, strengths did not increase noticeably. Internal temperature reached the maximum about 11 hours later the placement and decreased after removal of forms. The internal temperature varied depending on the location and the exposure condition. In addition, the internal relative humidity was more affected by the exposure condition rather than the cement content.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.1
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• pp.65-70
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• 2001

During the summer season, it is very hot and humid in Korea. So the humidity is an important factor regarding the environmental control function of building envelops. The purpose of this research is to measure and analyze the characteristics of such environmental factors as relative humidity, dry bulb temperature and air velocity varies both in the clay and cement envelop structures using granite dome models during the summer time. The interior relative humidity of the clay model is constant regardless of exterior humidity although a little range of variation is shown in comparison to the cement model.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.125-137
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• 1996

This study was designed to investigate effects of relative humidity on the breakthrough of charcoal tubes at a fixed vapor concentration and sampling time during mixed organic vapor sampling. A vapor generator was used to generate three different concentrations of mixed organic vapor and a stainless steel chamber was fabricated and utilized to maintain three different percentages of relative humidity while maintaining a constant temperature. The results were as follows; 1. At high relative humidity, breakthrough of mixed organic vapor occurred quickly at low vapor concentration than at high vapor concentration because of the reduced adsorption volume of charcoal tube due to humidity. 2. Breakthrough by competitive adsorption of vapors onto charcoal tube was observed at first from n-hexane having the lowest boiling point and highest vapor pressure among the three organic vapors investigated, followed by TCE. No breakthrough was observed from toluene under all experimental conditions. 3. For n-hexane, breakthrough was observed after 2 hours of sampling and breakthrough rates were increased as relative humidity increased. For TCE, breakthrough was found after 3 hours of sampling and breakthrough rates by sampling time were increased as vapor concentration increased. 4. The adsorbed amount of mixed organic vapor at breakthrough was shown to have statistically significant correlations with sampling time, relative humidity, and vapor concentration in descending order of correlation. Relative humidity and sampling time for n-hexane and sampling time and concentration for TCE were both statistically significantly correlated. 5. Relative humidity was found to affect the amount of breakthrough of mixed organic vapor and n-hexane. Among three percentages of relative humidity investigated, the amount of breakthrough at 85 % relative humidity was significantly larger than those of at lower percentages of relative humidity. No statistically significant difference was found between 25 % and 55 % relative humidity. 6. The results of multiple regression analysis between breakthrough and relative humidity, vapor concentrations showed that the coefficient of determination of mixed organic vapor was 0.263 and those of n-hexane and TCE were 0.275 and 0.189, respectively. 7. Flow rates of sampling pumps used were found to be affected by relative humidity present. At 25 %, 55 %, and 85 % relative humidity, the relative errors of sampling pump were 1.4 %, 13.4 %, and 18.6 %, respectively. In conclusion, the results of this study showed that high relative humidity could reduce the adsorption volume of charcoal tubes and subsequently increase breakthrough rates. Therefore, to prevent breakthrough when sampling mixed organic vapors, it is suggested that either sampling volume be reduced on the flow rate be lowered so as to minimize breakthrough of the most volatile organic vapor in the mixture. In addition, since the flow rates of a sampling pump can be adversely affected by high relative humidity, it is recommended to use a constant flow mode pump when sampling in the highly humid environment.