• Journal of Environmental Science International
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• v.11 no.8
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• pp.801-810
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• 2002

The current paper describes the indoor/outdoor air quality in school environments through analyses of the heavy metal concentrations using Inductive Coupled Plasma(ICP). School environments in a heavy traffic area, two industrial areas, quasi-industrial area, and residential area were evaluated. The results were as follows: (1) The locations with the highest indoor and outdoor concentrations of heavy metals were the industrial areas followed by the heavy traffic area, residential area, and quasi-industrial area in a descending order of magnitude. Plus, the indoor heavy metal concentrations were higher then the outdoor ones. (2) The main heavy metal components were Zn, Al and Ca. Higher concentration levels were found indoors than outdoors. The heavy metal concentrations were also higher in the classrooms than in the corridor or outdoors. (3) The total heavy metal concentrations in the studied areas were highly dependent on the weather elements. including the relative humidity, mixing ratio, and wet-bulb depression. Accordingly, special ventilation systems are recommended to reduce air pollution in school environments.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.36-43
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• 2008

This purpose of this study was to examine the effect of planting density, growing medium and strength of a nutrient solution (National Horticultural Research Institute's nutrient solution: HRI's) on the growth and development of Oriental hybrid lily 'Le Reve' in a box cultivation. The planting density with 14, 18 and 22 bulbs had sprouting one day earlier than other treatments. Planting density of 22 bulbs flowered first, while six bulbs flowered the last, indicating that higher planting densities led earlier flowering. The increasing planting density increased stem length of cut flowers. On the other hand, cut flower quality was improved when the planting density was lower. The incidence of physiological disorders such as blasting was more frequent in planting density of 22, 18, and 14, indicating that higher planting densities caused higher incidences of physiological disorders. All planting densities except 22 bulbs displayed superior results in width, weight, number, and scale weight of the bulbs. Greater planting densities led to inferior bulb enlargement and an increased decomposition rate. pH decreased in all treatments after the bulb enlargement and decreased more as the planting density increased. Contents of P, K, Ca, and Mg increased, while contents of K and Ca decreased, as the planting density increased. The rice hull+coir (1:1, v/v) treatment was better than others, but did not show that much of a difference. Moreover, in bulbs enlargement after cut flower harvest, lily medium and perlite+peat moss treatments showed superior results, and decomposition rate was the greatest in the rice hull+coir (1:1, v/v) treatment. In the HRI's solution strength treatment from the period of flower bud emergence to flower harvest, higher solution strengths gave better cut flower quality in terns of length, weight, and number of flowers. The non-treated control and one third strength of a HRI's solution hastened flowering, indicating that lower strengths led to earlier flowering. According to the results of leaf analysis as affected by solution strength during the flower harvest, absorption rates of N and K were greater when the strength was higher, and Ca and Mg showed the same tendency. On the other hand, the absorption rate of P was the lowest in all treatments.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.575-582
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• 2011

This experiment was conducted to study the qualitative changes of grafted cactus after harvest and to examine the decomposition characteristics of pathogenic fungi which occurs or grows during the simulated shipping period. Plant materials with four varieties of Gymnocalycium mihanovichii var. friedrichii including, 'Hukwang', 'Huhong', 'Hwangwol', 'Yeunhwa' and two varieties of Chamaecereus silvestrii f. variegate such as 'Goldcrown' and 'Yellowcrown' were used. During the simulated shipping period, the fresh-weight, bulb diameter, carbon dioxide emission rate, and decomposition rate were observed. The regeneration rate and decomposition rate were observed for the grafted cactuses that were placed in a greenhouse environment with a temperature of $28{\pm}12^{\circ}C$ and humidity of $36{\pm}15.3%$ after 40 days of simulated shipping. There were reductions in the fresh-weight and bulb diameter in every variety as time passed while the carbon dioxide emission rate showed no meaningful difference by each variety. Furthermore, the decomposition rate in the scion was higher than in the stock. According to the analysis of pathogenic fungi by decomposition characteristics, Alternaria sp., Cladosporium sp., Colletotrichum sp., Fusarium sp., Penicillium sp. in G. mihanovichii var. friedrichii were found and Alternaria sp., Bipolaris sp., Cladospoirum sp. in C. silvestrii f. variegate were identified. Therefore, to maintain and improve the quality of grafted cactus, it is necessary to analyze the factors of decomposition from the time of harvest until the point of export and develop a process technology to minimize the decomposition rate.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.95-101
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• 2012

This study was conducted to investigate the effect of climate conditions during cultivation and harvesting on the quality and storability of fresh bulb cabbage (Brassica oleracea L. var. capitata). Plug seedlings of six cabbage cultivars were transplanted to Gangneung-Wonju University high elevation research station in Gangwon province (780 m above sea level, lat. $37.5^{\circ}N$.) and harvested with four different harvest times like August 3 ($1^{st}$), August 13 ($2^{nd}$), August 23 ($3^{rd}$), and September 10 ($4^{th}$), respectively from 50 days after transplanting. Weight loss, Hunter color factors, firmness, and soluble solids content (SSC) of the cabbage bulbs were investigated during storage at $3^{\circ}C$ (85% RH) and $25^{\circ}C$ (60% RH). Decreased bulb weight and poor quality cabbages were apparent at the late transplanting (July 14) and harvest (September 10) respectively. Quality index such as firmness and SSC at August 23 ($3^{rd}$) harvested cabbage was better than August 3 ($1^{st}$) and August 13 ($2^{nd}$) cabbages due to the good weather condition just before harvesting. The cv. 'Speed king' and 'Minix 40' showed good qualities among the cultivars, especially when the bulbs were harvested during sunny day conditions from one week before harvesting. Also SSC was influenced by weather condition before harvesting rather than transplanting date, while firmness was influenced by transplanting and harvest date. However, the differences among the cultivars were not significant. The potential of storage as maintaining the quality was different, depending on weather conditions at harvest time. Generally the storage periods of six cultivars were around 3~5 days and 9~10 days at room and low temperature, respectively. However, the August 3 ($1^{st}$) harvested cabbage lost their marketable quality very fast because of rainy and cloudy weather condition before harvesting and also storability of bulbs was 2 days and 4 days at room temperature and $3^{\circ}C$, respectively. Quality index was also not significant difference among cultivars.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.101-105
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• 2003

This experiment was conducted to find out the effect of day length on the production of high quality plug seedlings in onion (Allium cepa L.). Two cultivars, ‘Changnyongdaego’ and‘Wolryun’, were grown to seedlings in 200-cell plug trays under 11.5, 12.5, 13.5 hours and natural day length. These seedlings were transplanted to the pot (16 cm In diameter) and grown under 16 hours day length. Number of leaves and neck diameter showed better growth in the longer than shorter day length treatments, but plant height old sheath length were retarded in the longer day length treatments. Growth such as no. of leaves, neck diameter, plant height and sheath length increased with the passage of day, but plant height and neck diameter decreased by treatment over 20 days with 13.5 hours day length. Bulbing and bulb size of onion after transplanting were enhanced in the seedlings cultured under longer day lengths. From the above results, treatment of long day length during seedling culture in plug tray can control the overgrowth and produce high quality plug seedlings.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.183-193
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• 1988

The relationship between the sulfur fertilization, and the quality and yield of garlic was investigated. The garlic was grown in pot and field at the five fertilization levels of sulfur. The growth characteristics, yield and flavour components of the garlic were studied. The results were summarized as follows; 1. The sulfur applications contributed to a weight and yield of the bulb in SP-10 (10kg/10a) and SF-20 (20kg/10a) significantly, respectively. 2. From the volatile oil obtained by steam distillation of garlic, fourteen organie sulfur components were separated, identified and quantified by GC and GC/MASS and the SP-10 and SF-20 were higher in the concentration of the flavour components in the volatile oil than other treatments. 3. It is considered that the organic sulfur components were synthesized in the top and transported to the bulb of the garlic. 4. In conclusion, SF-20, 20kg/sulfur per 10a, could be recommended to get maximum yield and a good quality of garlic in view of evaluation through the contents of organic sulfur components in the volatile oil and the yield of the bulb.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.64-68
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• 2014

This paper introduces the use of a crown-shaped (CR) lens to effectively diffuse the light from a light-emitting diode (LED) without any loss in the light intensity, in contrast to polymer-bulb-type diffusers. The diffusion lens was designed based on the Snell's law, which describes the physical path of a ray passing through the boundary between different media. CR lenses were fabricated by polydimethylsiloxane (PDMS) casting and UV-embossing processes, which used a pre-designed metal mold and UV-curable resin, respectively. Through experiments and optical evaluations, it was verified that the newly proposed CR lens not only decreased the vertical light strength and glare effect from an LED light source but also improved the diffusion characteristics while maintaining the quality of the LED's light intensity.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1470-1471
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• 2008

We present a front-side micromachined thermopile with high sensitivity in the 3-5${\mu}m$ window, and discuss its application to a novel non-dispersive infrared (NDIR) $CO_2$ gas sensor with a light source emitting collimated light. The micromachined thermopile shows a measured sensitivity of 30 mV/W and a $D^*$ of $0.3{\times}10^8cm^{\surd}Hz/W$. Using this newly fabricated thermopile, we also have successfully developed a small, sensitive NDIR $CO_2$ detector module for accurate air quality monitoring systems in energy-saving building and automotive applications. The novel sample cavity comprising specular reflectors around the light bulb is configured to uniformly emit collimated light into the entrance aperture of the cavity in order to enhance the sensitivity of NDIR $CO_2$ detector.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.372-380
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• 2008

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. Paper heat exchanger can recover $50{\sim}70%$ of the enthalpy difference between supply and exhaust air. The purpose of this research is to obtain the experimental correlations for the friction factor, heat transfer coefficient, mass transfer coefficient and permeance of paper heat exchanger, which can be used to predict the performance of the paper heat exchanger. Pressure drops at various velocities, and sensible and latent heat transfer rates at various dry-bulb temperatures, relative humidities and specific humidities are measured to derive experimental correlations. The results of prediction using correlations show fairly good agreement with the experimental data obtained in the actual operating conditions.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.341-350
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• 2019

Garlic is one of the most popular seasoning bulb vegetables in Korea and is the most commonly used food ingredient. However, the cultivation areas are decreasing every year as the price drops due to imported garlic, and labor is insufficient to produce garlic by conventional methods. Cultivation requires various tasks until garlic is harvested. Seeding is one of the important and laborious tasks; thus, mechanization is necessary. When seeding garlic, the sprout should face upwards; otherwise, it may rot or produce poor quality garlic. This study investigated the extent of growth of northern- and southern-type garlic in eight different positions. The results show when the roots were not planted properly, the stems were weak, and the garlic bulbs were small. A simple garlic planter was manufactured with a crank-press mechanism to plant garlic in an upright position. Using this machine, a three-fold experiment was carried out with 100 strips of garlic. The test results showed that 99.4% of the planted garlic strips were positioned upright or close to being upright, and 0.6% failed to take root. An image processing algorithm was developed to locate the root part of the garlic, and the result showed a success rate of 81%. A future study will develop an automatic garlic upright planting system with a viewing system.