• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.70-78
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• 2012

For evaluating the printing suitability of electronic copying papers in the aspect of climate conditions, 12 samples of copying papers being generally used in Korea and worldwide were collected. The copying papers were controlled by various temperature and humidity options in conditioning equipment in order to simulate the specific circumstances of dry, temperate or tropical climate, and the pre-heating system of photocopying machines during printing. As results, some copying papers showed several physical problems, especially in recycled copying papers and a normal paper with original printing faulty. These problems of copying papers were mostly resulted in extremely high moisture circumstance, and in lower levels of tensile strength and tensile stiffness. The moisture contents of copying papers during passing through the pre-heater system of photocopying machine could be rapidly decreased because paper is exposed to high temperature around the pre-heating zone. The copying paper, for example of XR3 sample, containing low moisture contents below 2% had high exfoliating possibility of toner transfer from copying paper.

• KIEAE Journal
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• v.12 no.6
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• pp.93-98
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• 2012

The concerns on high ozone concentration phenomenon is significantly growing in Seoul metropolitan area including the industry complex area, like Shiwha Banwol area. The aims of this research is the analysis of relationship between high concentrations of $O_3$ and solar radiation parameters in atmosphere. The understanding of the effects of solar radiation intensity, humidity, high air temperature on ozone concentration in a day is very useful to provide a direction for reducing of the high ozone concentration to a local government or a metropolitan government. The correlation analysis between maximum ozone concentration and various meteorological parameters in 2009 - 2011 carried out using IBM's SPSS program. The results showed that the mean correlations coefficient (R) between daily Ozone maximum and solar radiation resulted R = 0.64 during 2011. May - September in 10 air pollution stations. In case of correlations between daily ozone maximum and relative humidity showed negative correlation R = -0.61. The correlation analysis with mean air temperature during 1-3 PM resulted R = 0.29. This low correlation coefficient could be corrected by using of categorized data of ozone concentration. The daily maximum ozone concentration is more dependent on peak solar radiation and high air temperature during 1-3 PM than its simple daily maximum values. The results of this research would be used to develop the high ozone alert system around Seoul metropolitan area. This correlation analysis could be partially integrated to prediction of ozone peak concentration in connection with other methods like classification and regression tree(CART).

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1103-1108
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• 2010

This study was conducted to be used as basic data of environmental friendly construction planning by comparing and analyzing thermal environment, find particles and biotope area rate according to land cover types of outside space of schools located in Chung-ju. When meteorological factors were analyzed according to land cover types, for temperature planting area and paved area showed low-and high-temperature ranges, respectively, and relative humidity was negatively related with temperature as low-and high-temperature ranges corresponded to high-and low-humidity ranges, respectively. For Wet Bulb Globe Temperature Index (WBGT) by land cover types, it was observed to be artificial grass> bare land> natural grass. Find particles were different according to land cover types of playground with being bare land> artificial grass> natural grass in the order. Bare land playground, where there were artificial factors and no absorption of fine particles through stomata of leaves as a function of natural circulation, recorded the highest level of $39.8\;{\mu}g/m^3$ and the level was relatively higher compared to the levels by season in Chung-ju. Biotope area rate showed the order of M elementary school> K elementary school> C commercial high school. That was considered to be caused by the difference of land cover type of school playground accounting for a large part of a school.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.208-223
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• 1994

The purpose of this study was to evaluate the efficiency of diffusive(or passive) sampler in measuring airbone organic solvents. Diffusive samplers are generally simple in construction and do not require power for operation. The efficiency of the diffusive samplers has not sufficiently been investigated in Korea. Three types of samplers were studied in this study. The sampling and analytical results by passive samplers were compared with results by charcoal tube method recommended by NIOSH(National Institute for Occupational Safty and Health). The following characteristics are identified and studied as critical to the performance passive monitors; recovery, reverse diffusion, storage stability, accuracy and precision, face velocity and humidity, n-Hexane, TCE(trichloroethylene) and toluene were used as test vapors. A dynamic vapor exposure system consisting of organic vapor generator and sampling chamber for evaluating diffusive samplers are made. The results of the study are summarized as follows. 1. NIOSH recommands that the overall accuracy of a sampling method in the range of 0.5 to 2.0 times the occupational health standard should be ${\pm}25$ percent for 95 percent confidence level. Among three types of diffusive samplers, sampler A has permeation membrane and samplers Band C have diffusive areas, samplers A and B met the criterion that overall accuracy for 95% confidence level of the samplers were within ${\pm}25$ percent of the reference value. Sampler C had overall accuracy ${\pm}9.6%$ and ${\pm}11.8%$ in hexane and TCE, respectively. The concentration of toluene was overestimated in sampler C with overall accuracy of ${\pm}43.9%$. 2. The desorption efficiencies of diffusive samplers were 96-107%. 3. There was no significant sampe loss during four weeks of storage both with and without refrigeration. 4. There was no significant reverse diffusion, when the samplers were exposure to clean air for 2 hours after sampling for 2 hours at the level of 2 TLY. 5. In case of 8 hours sampling, relative differences(RD) of concentrations between charcoal tube method and diffusive method were 15-39%, 13-46%, and 4-35% for sampler A, B and C, respectively. The performance was poor in 8 hours sampling for multiple substance monitors. 6. At high velocity(100 cm/sec), samplers B and C overestimated the concentrations of organic vapors, and sampler A with permeation membrance gave better results. 7. At 80% relative humidity, samplers showed no siginificant effect. Low humidity also did not affect the diffusive samplers.

• Particle and aerosol research
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• v.9 no.4
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• pp.247-252
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• 2013

Removal of water contents in a gas is needed in industrial field of gas processing related on energy production/conversion, and environmental treatment. Inertial separators are economic devices for separating droplets from the gas stream. For design and incorporation of inertial pre-treatment separator, characteristics of removal of water contents with various operation conditions are needed. In this study, removal efficiency of water droplets at various flowrates (5-14 SCMM) and relative humidity (R.H.) conditions (40%, and 90%) has been investigated. At low R.H. condition, the removal characteristic is similar to the removal of solid particles. But, droplet growth resulting from the condensation of water vapor at high R.H. condition, is significant and it made increase in removal efficiency of droplet phase of water contents. For rapid removal of water contents, an effective method to enhancing condensation growth of water droplets is highly needed.

• Atmosphere
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• v.25 no.2
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• pp.309-322
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• 2015

The objective of this study is to evaluate the impact of the high resolution topographies and landuses data on simulated meteorological variables (wind speed at 10 m, temperature at 2 m and relative humidity at 2 m) in WRF. We compare the results with WRF simulation using each resolution of the topographies and landuses, and with 37 AWS observation data on the Seoul metropolitan regions. According to results of using high-resolution topography, WRF model gives better topographical expression over domain. And we can separate more detail (Low intensity residential, high intensity residential, industrial or commercial) using high resolution landuses data. The result shows that simulated temperature and wind speed are generally higher than AWS observation data. However, simulation trend with temperature, wind speed, and relative humidity are similar to observation data. The reason for that is that the high precipitation event occurred in CASE 1 and 2. Temperature have correlation of 0.43~0.47 and standard deviation of $2.12{\sim}2.28^{\circ}C$ in CASE 1, while correlation of more than 0.8 and standard deviation of $3.05{\sim}3.18m\;s^{-1}$ in CASE 2. In case of wind speed, correlation have lower than 0.5 and Standard Deviation of $1.88{\sim}2.34m\;s^{-1}$ in CASE 1 and 2. In statistical analysis shows that using highest resolution (U01) results are more close to the AWS observation data. It can be concluded that the topographies and landuses are important factor that affect model simulation. However, the tendency to always use high resolution topographies and landuses data appears to be unjustified, and optimal solution depends on the combination of scale effect and mechanisms of dynamic models.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.1
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• pp.17-24
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• 2014

We measured black carbon concentration in rural area to understand the characteristic of atmospheric aerosol by comparing the black carbon concentration and meteorological factors such as PM10 concentration, relative humidity, temperature and wind velocity. A MAAP (Multi Angle Absorption Photometer) which is one of filter based equipments was used to measure black carbon concentration. Black carbon concentration was measured to be high from April to May and low from June to September. Black carbon concentration was proportional to PM10 concentration. Black carbon concentration was correlated to relative humidity. Black carbon concentration was inversely proportional to wind velocity and temperature. Finally, we suggest that the volume fraction of black carbon in the atmosphere can be estimated from the size, number concentration and absorption coefficient measured using the MAAP.

• Atmosphere
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• v.18 no.3
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• pp.237-248
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• 2008

A thermal index which considers metabolic heat generation of human body is proposed for operational forecasting. The new thermal index, Perceived Temperature (PT), is forecasted using Weather Research and Forecasting (WRF) mesoscale model and validated. Forecasted PT shows the characteristics of diurnal variation and topographic and latitudinal effect. Statistical skill scores such as correlation, bias, and RMSE are employed for objective verification of PT and input meteorological variables which are used for calculating PT. Verification result indicates that the accuracy of air temperature and wind forecast is higher in the initial forecast time, while relative humidity is improved as the forecast time increases. The forecasted PT during 2007 summer is lower than PT calculated by observation data. The predicted PT has a minimum Root-Mean-Square-Error (RMSE) of $7-8^{\circ}C$ at 9-18 hour forecast. Spatial distribution of PT shows that it is overestimated in western region, while PT in middle-eastern region is underestimated due to strong wind and low temperature forecast. Underestimation of wind speed and overestimation of relative humidity have caused higher PT than observation in southern region. The predicted PT from the mesoscale model gives appropriate information as a thermal index forecast. This study suggests that forecasted PT is applicable to the prediction of health warning based on the relationship between PT and mortality.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.88-92
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• 2002

The study was conducted to estimate stimulation of plant growth of blue and red leaf lettuce (Lactuca sativa L.) as affected by covering methods with vinyl materials containing concentrated PO film. Plants were grown in direct, direct and tunnel, and tunnel covering with 'Pasraido materials' from October 13 to 31. With the covering mean air temperature, soil temperature, leaf temperature and relative humidity remarkedly increased. Higher temperature was observed in the order of direct and tunnel, direct, tunnel covering and the control. Photosynthetic photon flux (PPF, $\mu$mol m$^{-2}$ . s$^{-1}$ ) was observed in reverse order of temperature. Concentration of $CO_2$ was higher during night than during day under the light. Accumulation of highest $CO_2$ at night was obtained from direct coverings followed by direct and tunnel, tunnel covering and the control. Plant height, leaf number and leaf area of blue and red lettuces were stimulated by direct covering. However, there was no significant difference.

• Journal of Life Science
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• v.28 no.4
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• pp.472-477
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• 2018

Pravastatin sodium is a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor used in the treatment of hypercholesterolemia by reducing cholesterol biosynthesis. Pharmaceutical excipients of commonly used including water, diluents, stabilizers, disintegrants, lubricants and colorants, and were identified for compatibility. All tests were performed by means of physical mixture of pravastatin and the excipients, which were placed in a press-through-pack (PTP) and incubated under accelerated conditions ($40^{\circ}C$ and 75% relative humidity) for 3 months. The blends of pravastatin with all excipients developed white, off white, and light brown powders, which showed no changes upon visual analysis. Accelerated conditions changed the degradation profile of pravastatin calcium in the HPLC system when mixed with different excipients. Although most excipients can have minor effects on pravastatin stability, the major degradation product from pravastatin was lactone. Low-level interaction (assay and impurity) was induced by all excipients except for microcrystalline cellulose and croscarmellose sodium. These excipients increased lactone impurity in 3 months by as much as 0.22% and 0.18% respectively. The total mixture slightly increased the lactone impurity (by 0.43% in 3 months) of pravastatin. There was no change in the assays of all excipients. These results will be helpful in studying tablet size reductions for convenience of use.