• Magazine of the Korean Society of Agricultural Engineers
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• 제16권1호
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• pp.3263-3291
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• 1974

Experimental work of grain bin was carried out to develop the methods of natural air in-bin drying and storage. The method is considered to be more economical, labour saving, and an effective countermeasure to grain loss. To examine the possibility of farm use of the grain bin and to analyze the related factors concerned with in-bin grain drying and storage, ambient air conditions (especially the change of air temperature and relative humidity) and grain quality during drying and storage periods were investigated. A laboratory model bin was constructed to investigate the effect of different forced air conditions on the drying characteristics of rice. In addition, a grain bin with 2.2m diameter and 1.8m height, considered to be the optimum size for the average Korean farm, was constructed and tested to examine the drying and storing characteristics of rice. The weather data analyzed in this study was the nine-year (from 1964 to 1972) record of air temperature and relative humidity in the Suweon area, and the thirty-year (from 1931 to 1960) record of pentad normal relative humidity and air temperature in the Seoul area. From the results of the weather data analyses, the adequate air delivery hours (which was arbitrary defined as the condition to give less than 75% relative humidity) to dry the rice during October were about nine hours (from approximately 10 A.M. to 7 P.M, ) a day, in which the average air temperature was about 15.9$^{\circ}C$ and average relative humidity was 66%. The occurence of days having three hours of such conditions was 1, 2, and 1-day within the 1st, 2nd add last 10-day periods for the month of October, respectively. Therefore, it may be considered that the weather condition in October was satisfactory for the forced natural air drying. The results of the laboratory model bin test were analyzed to obtain the drying curve and drying rate for different drying stages and grain layers in the bin corresponding to various conditions of forced natural air. A drying experiment with a prototype grain bin showed that an approximate 5 percent grain moisture gradient through a 1.6 meter grain deposit was observed after 80 hours of intermittent drying, giving an over dried zone in the lower grain layers and an extremely high grain moisture zone in the upper layers. This indicates that an effective measure should be taken to reduce this high moisture gradient. In order to investigate the drying characteristics of bulk grain in a layerturning operation a grain bin test was performed. This showed a significant improvement of uniform drying. In this test, approximate 107 hours were required to dry a depth of 1.6 meter of grain from an initial moisture content of 22.2 percent to a moisture content of 16.7 percent using an air delivery rate of 2.8 cubic meter per a minute per every cubic meter of grain. This resulted in a 2 percent moisture gradient from the top to the bottom of the bin. During storage period, till the end of June the average temperature of grain was 2~3$^{\circ}C$ higher than ambient air temperature. But during July when the grain moisture content went up slightly (less than 1 percent), the average temperature of the grain also increased to 3~5$^{\circ}C$ higher than ambient air temperature. It is therefore recommended that for safe grain storage, grain should not be stored in sheet metal bins after mid May. From the above results, in-bin rice drying and storage can be used effectively on Korean farms. It is strongly recommended that the use of grain-bin system should be implemented for farm use to improve farm drying and storage of rice.

• Fashion & Textile Research Journal
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• 제22권5호
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• pp.686-695
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• 2020

The present study evaluated the manual dexterity and usability of conductive gloves when operating touchscreen devices in the cold. Twelve male subjects (23.3±1.5 years in age) participated in three experimental conditions: no gloves, fabric conductive and lambskin conductive gloves. Manual dexterity was tested using both Purdue Pegboard (PP) and ASTM dexterity tests at an air temperature of 5℃ and air humidity of 30%RH. Glove usability was tested through the following touchscreen tests: tap, double tap, long tab, drag, flick, and multi-touch. The results showed that manual dexterity according to the PP (2.5 mm of a pin diameter) and ASTM tests (8 mm of a stick diameter) was worse for the two glove conditions than for the no glove condition (p<.005). PP dexterity was better for the fabric glove condition than for the lambskin glove condition (p<.05); however, there was no difference in ASTM dexterity between the two glove conditions. Hand and finger skin temperatures were higher for the glove conditions than the bare hand condition (p<.05), with no differences between the two glove conditions. The touchscreen usability was the best for the no glove condition, followed by fabric gloves (p<.05). Wearing either fabric or lambskin gloves diminishes hand dexterity while maintaining hand and finger temperatures at higher levels. For improved hand dexterity in dealing with small numbers, letters on a touchscreen in cold environments, we recommend wearing fabric conductive gloves rather than lambskin conductive gloves.

• Journal of Korean Society for Quality Management
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• 제42권4호
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• pp.757-768
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• 2014

Purpose: In this paper we present a case study of developing fast curing adhesives for insulation material of LNG carriers using an extreme vertices design with four mixture components. Three material properties are considered - shear strength, viscosity, and tensile strength. In the optimization experiment, we used hardness instead of tensile strength due to shortage of specimens. Methods: We employ four-factor extreme vertices design with 19 runs and desirability function approach for simultaneously optimizing three responses. After selecting optimal condition of the mixture components, we do confirmation experiments to verify the reproducibility of the optimal condition under manufacturing circumstance. Results: Simultaneous optimal condition for the three responses, that is, shear strength, viscosity, and harness is obtained. At the optimal condition, confirmation experiments are executed in manufacturing circumstance. The variation for the shear strength is not satisfactory, which is due to the variation of the humidity. Conclusion: At the optimal condition three material properties are satisfactory. To reduce the variability for the shear strength, robust design is needed.

• Journal of Mushroom
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• 제14권3호
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• pp.119-126
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• 2016

Five empirical farmhouses were selected to reduce the high temperature damage in oak mushroom cultivation using bed-logs. The cultivation facilities were categorized as follows: those having two blackout curtains or one blackout curtain and outdoor oak mushroom cultivation. The inequality of the indoor condition, oak mushroom hyphae rampant ratio, and fruit body production in each test condition was evaluated. $3^{\circ}C$ was lower in indoor temperature of cultivation facility having two blackout curtains than one blackout curtain. Specifically, the indoor air humidity average of cultivation facilities having one or two blackout curtains was 10% lower than that of outdoor oak mushroom cultivation. This condition is not ideal for oak mushroom cultivation as continuous indoor humidity control is essential for producing good fruit bodies. The Inoculated bed-log surface and oak mushroom hyphae rampant ratio of bed-logs cultivated with two blackout curtains was superior to other tested conditions. The mushroom production ratio observed in facilities with two blackout curtains was 117-204% higher than those cultivated in facilities with only one blackout curtain. Furthermore, the mushroom production ratio increased in based on these findings, we recommended five cultivation facility models to reduce high temperature damage in oak mushroom cultivation using bed-logs.

• Journal of Bio-Environment Control
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• 제12권3호
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• pp.127-131
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• 2003

This study was conducted to establish the ventilation fan operation schedule to be able to provide satisfactory environment for colonies in thc wintering honey bee house. The simulation and practical measuring test were conducted to verify the applicability of an existing simulation program to thc calculation of inside thermal environment condition of the house, and the environment control performance was compared between the two types of fan operation schedule to find the proper schedule. It was concluded that the program could be used to design thc materials of the enclosure and the fan operation schedule and decide the number of accommodation hives. Inside temperature of bee house controlled by the fan operation schedule B was lower than the schedule A under the similar high outside temperature condition. In the presence of the high outside temperature condition, inside air temperature of bee house could be decreased by changing fan operation schedule A to schedule B. The humidity variation in bee house controlled by the tan operation of schedule B was smaller than that by schedule A. These results indicated that the schedule B was superior in the aspect of the environment control performance.

• Journal of the Korean Society of Hazard Mitigation
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• 제9권3호
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• pp.95-100
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• 2009

Fine fuel moisture code (FFMC), a main component of forest fire weather index(FWI) in the Canadian forest fire danger rating system(CFFDRS), indicated a probability of ignition through expecting a dryness of fine fuels. According to this code, a rising of temperature and wind velocity, a decreasing of precipitation and decline of humidity in a weather condition showed a rising of a danger rate for the forest fire. In this study, we analyzed a weather condition during 5 years in Kangwon province, calculated a FFMC and examined an application of FFMC. Very low humidity and little precipitation was a characteristic during spring and fall fire season in Kangwon province. 75% of forest fires during 5 years occurred in this season and especially 90% of forest fire during fire season occurred in spring. For developing of the prediction model for a forest fire occurrence probability, we used a logistic regression function with forest fire occurrence data and classified mean FFMC during 10 days. Accuracy of a developed model was 63.6%. To improve this model, we need to deal with more meteorological data during overall seasons and to associate a meteorological condition with a forest fire occurrence with more research results.

• Asian-Australasian Journal of Animal Sciences
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• 제6권3호
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• pp.389-394
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• 1993

A study on housing and management of dairy cows was conducted in three villages. All activities of husbandry related to the housing and the condition of the cows were observed and farmers were interviewed using a questionnaire. The main type of housing was a tie stall mostly in the back yard area with a gable or shed type roof. Inside the shed the temperature ranged from 17 to $29^{\circ}C$ and the relative humidity ranged from 62 to 73%. Drainage and manure handling was poor which lead to poor cleanliness of the stables and animal skins. The floor space was mostly wide and the roof level was low (less than 2.5 m). The slope of the floor (1-3%) was sufficient, the roughness of the floor was of medium quality. The shape and size of the feed trough was good with a surface of mostly irregular forms. Concentrate was mixed with water and offered in liquid form in pails made from plastic or from parts of rubber car tires. Hoof length was too long which could lead to unstable position and self injury. It is concluded that the housing conditions of dairy cattle need to be improved in order to improve the condition of the animals and the production performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제18권1호
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• pp.66-72
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• 2006

This article presents the optimal operation of an air conditioner using thermoelectric modules. A prototype of air conditioner using four thermoelectric modules has been designed and built. The system performance with evaporative cooling for hot side of the module are studied in detail for several operating parameters, such as input power to the thermoelectric module, fans and pump. It is found that the optimal input voltage to the thermoelectric module and pump is selected for the best system performance based on the cooling capacity and the COP at a given operating condition. It is also found that both the cooling capacity and COP of a system is increased with an increase in the input power to fans. The cooling performance could be improved when the ambient temperature is increased and the relative humidity is decreased since the evaporative cooling at the hot side has been increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제15권12호
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• pp.1049-1059
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• 2003

R410A is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the heat transfer and pressure drop for R410A flowing in a fin-and-tube heat exchanger used for commercial air-conditioning units. Experiments were carried out under the conditions of inlet refrigerant temperature of 6$0^{\circ}C$ and refrigerant mass flux varying from 150 to 250 kg/$m^2$s for refrigerant side. The inlet air has dry bulb temperature of 35$^{\circ}C$, relative humidity of 40% and air velocity varying from 0.68 to 1.6 m/s. Experiments show that air velocity decreased by 16% is needed for R410A than that of R22 for subcooling temperature of 5$^{\circ}C$, which resulted in air-side pressure drop decrease of 15% for R410A as compared to R22. As a consequence, in order to provide the same design condition of a condenser, the fan requires lower electric-power consumption with R410A than that with R22.

• Journal of the Korean housing association
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• 제21권6호
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• pp.11-18
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• 2010

The aims of this study were to grasp the real condition state and clarify the characteristics and influence of pollutants on the indoor air pollution in occupied apartment units. The research method was to measure the pollution levels of indoor air pollution, and investigate characteristics of the pollutants such as the outdoor environment, elapsed time after construction, finished materials, temperature, relative humidity, space extension, purchase with furniture and electric appliances, built-in closets, and method for cleaning the air. And these were made a comparition between industrial and residential area. The VOCs and formaldehyde concentration in indoor air were measured the 6 household in residental area and 5 household in industrial area. In conclusion, the concentration such as benzene, ethylbenzene, toluene, xylene, styrene showed the pollution state within permissible levels, however formaldehyde concentration has need a lot of attention as ever. And it turned out that the influence with reference to emission from building materials on indoor air pollution lessened under 18 months elapsed time after construction.