• Journal of Energy Engineering
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• v.19 no.4
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• pp.228-233
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• 2010

About 55% of total energy is consumed in the industrial division. The industrial heat pump application will show magnificent energy saving effect as well as higher cost efficiency because of larger energy consuming volume of each facility and longer operation hour and higher stability against seasonal temperature change. Over 90% of dryer for industrial usage has hot wind heat source and hot wind dryer is the representative type covering 68.7% while its 30 ~ 50% lower heat efficiency causes lots of energy loss by exhaust air. Re-usage of exhaust air can improve energy efficiency of dryer because 68% heat energy or 78% of hot air lose in exhaust air. Therefore, high temperature heat pump dryer can be the best alternative. Comparing to the existing dryer with 30% ~ 50% energy efficiency, newly developing high temperature heat pump dryer will enhance energy efficiency up to 60% ~ 80% efficiency. In this paper, heat pump system for high temperature was designed, constructed and tested. The results have shown that system COPh is estimated as 3.3.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.29-39
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• 2018

Long-term variation of zooplankton community and species composition was studied from 2003 to 2014 in a deep reservoir, Lake Soyang, in monsoon climate region, Korea. In addition, we examined the correlation with environmental factors. Annual precipitation of watershed showed a large variation in the $705{\sim}1,779mm\;yr^{-1}$ and more than 70% of it was being concentrated from June to September. The water quality of Lake Soyang was shown a clearly seasonal variations and particularly turbid water flowing into the lake during rainy season was the most important environmental factors. Zooplankton community in Lake Soyang showed a significant difference before and after 2006. Zooplankton biomass has shown a large increase and also showed a change in the zooplankton community structure since 2006. The of zooplankton showed positive correlation with temperature and BOD, Chl. a, TP concentration. These results are considered that nutrient and organic matter contained in the turbid water influences the increase in zooplankton biomass and species composition. However, water quality was limited to account for the increase in biomass of zooplankton. For example, increase of small zooplankton density (rotifer; Keratella cochlearis, Polyarthra vulgaris) in spring which is dominated by diatoms (large size; Melosira, Synedra etc.) is considered as a bottom-up effect by the microbial loop. And increased density of crustaceans in autumn was considered a top-down effects by the relationship between predator and prey of microzooplankton and mesozooplankton. In other words the inflow of allochthonous organic matter during rainy season also affected to zooplankton food web in Lake Soyang. In conclusion, biomass, diversity and long-term variations of zooplankton in Lake Soyang were determined by physico-chemical factors but also it is considered that biological interactions is important.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.419-429
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• 2017

We investigated the occurrence pattern of diseases and insect pests and disease control efficacy of organic materials against watermelon powdery mildew in small type watermelon in Eumseong, Chungcheongbuk-do, 2015. The result of this study, the small type watermelon was damaged by diseases and pests such as Didymella bryoniae, Podosphaera xanthii, Aphis gossypii, Tetranychus urticae, thrips, Spodoptera exigua and Spodoptera litura. Among them, the occurrence of P. xanthii, T. urticae and thrips was high. Diseased leaf rate by P. xanthii, a casual agent of powdery mildew, was 27~99.3% in three small type watermelon cultivars in the middle of June. The number of T. urticae per leaf was high from 79.9 to 111 in three small type watermelon cultivars in the middle of June. It showed high number of thrips captured by yellow and blue sticky trap. Highest numbers of yellow sticky trap (407) and of blue sticky trap (774) were detected in the middle and first of June, respectively. The disease control efficacy of mayonnaise, oleic acid and three organic materials against powdery mildew of small type watermelon in fields was evaluated. As thre results, the symptoms of plant disease were effectively reduced by over 60% in the treatments of materials such as sodium bicarbonate 80%, mayonnaise and the extract of Rheum palmatum 1%. The highest control efficacy was 83% in the treatment of sodium bicarbonate 80%. From this study, we had a information of the occurrence pattern of diseases and insect pests in small type watermelon and the treatment of material containing sodium bicarbonate 80% was very effective for controlling against powdery mildew.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.31-41
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• 1997

This study was carried out to investigate the composition and the distribution of the benthic community in the coastal area of Inchon seasonally from May 1994 to February 1995, and to estimate the environmental factors that effect the temporal and the spatial changes of benthic species composition. In the present study, 231 species were collected with the average density of 455 ind./$m^2$. The dominant species were Heteromastus sp., Sternaspis scutata, Chaetozone setosa, Mediomastus sp., Glycinde sp., Glycera sp. and Nephtys oligobranchia, which are in the polychaete group; abundance of these species showed seasonal and spatial variations. The study area was divided into 4 regions by cluster analysis such as outside area of Palmido (I), main channel region and adjacent are of Shihwa sea wall (II), north-eastern area of Youngjongdo (III), and the Inchon harbor and the mouth area of Sorae harbor (IV). The particle size of sediment which generally influences the distribution of the benthic community, the differences of the concentration of heavy metals, and of the dissolved oxygen, the increase of the proportion of polychaetes and molluscs, the absence of the crustacean phoxocephalids, and the increase of the abundance of pollution indicator species, indicated that the environment of the areas have been degrading gradually from Group I to Group IV.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.1-7
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• 2019

In response to the recent increase in demand for hydrogen stations, the Ministry of Trade and Industry has enacted and promulgated special notifications to enable the installation of hydrogen stations in the form of the combined complex in existing automotive fuel supply facilities such as LPG, CNG, and gas stations. Hydrogen multi energy filling stations haven't been operated yet in Korea till the establishment of special standards, so it is necessary create special standards by considering all Korean environmental characteristics such as four seasons and daily crossings. In this study, we collected and analyzed the charging data of Ulsan LPG-Hydrogen Multi Fueling Station installed for the first time in Korea. The data are hourly temperature and pressure data from compressors, storage vessels and dispensers. We used the data collected for a year, including the highest temperature and the lowest temperature in Ulsan to compare seasonal characteristics. As a result, it was found that the change of the outside temperature affects the initial temperature of the vehicle's container of the hydrogen car, which finally affects the charging time and the charging speed of the vehicle. There was no effect on vehicle containers because the limit temperature suggested by the Korean Hydrogen Station Standard(KGS FP217) and the US Filling Protocol(SAE J2601) was not exceeded.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.135-140
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• 1988

This field experiment was carried out to determine the effects of cutting times (3,4 and 5 times $yr^{-1}$) and cutting heights (3, 6 and 9 cm) on the growth and dry matter(DM) yield of grasses grown under pine trees, and botanical composition of woodland pasture. The conditions of the experimental field was south direction with 30% of shade (ca. 70% of full sunlight). Annual DM yield was higher in the plots cut 4 times (6,097 kg) and 3 times (5,953 kg) than in 5 times (5,305 kg $ha^{-1}$). However, it ip considered that total nutrient yields may be not different among 3 treatments. The yield was significantly (P < 0.05) increased with higher cutting height, regardless of cutting time. The 9 cm of stubble height was very effective on both increasing DM production and seasonal distribution of DM. In botanical composition, 3 cm and 6 cm of cutting height accelerated the percentages of bareland and weeds, regardless of cutting time, particularly in summer season. However, 9 cm of stubble height maintained 80-85% of pasture grasses in all cutting times. In this experiment, therefore, cutting height was more important factor than annual cutting times for forage production and pasture longevity, and it is desirable to harvest 4-5 times per year (under this experimental field condition) with 9 cm of stubble height on woodland pasture.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.278-284
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• 1990

A study relating the soluble-solids (S.S.) contents of Chinese cabbages to the final titratable acidities(TA) of kimchis was conducted. The S.S. contents of Spring-sowed Chinese cabbages were in the range from $1.20-3.40^{\circ}$ Brix while those of Autumn-sowed Chinese cabbages were in the range from $3.8-6.6^{\circ}$ Brix. The S.S. contents of Chinese cabbages were varing depending on their varieties and the cultivating seasons. However, seasonal variations were much more significant than the varietal variations. The final TAs of kimchis after complete fermentation were found to be directly proportional to the S.S. contents(x) of Chinese cabbages, showing that TA equals to 0.30x+07779. From the equation, a Chinese cabbage of a S.S. content with up to $0.02^{\circ}$ Brix, which is practically impossible to obtain, will make a kimchi which will not be overacidified during the prolonged storage period without any preservative measures.

• The Korean Journal of Malacology
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• v.28 no.2
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• pp.131-136
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• 2012

Growth, oxygen consumption, ammonia excretion, feeding and assimilation rate were examined from May 2010 to February 2011 in order to assess the physiological changes of Haliotis discus hannai in accordance with changes in season. The water temperature was in the range of $8-23.2^{\circ}C$ and the salinity in the range of 31.9-34.1psu during the examination period. The length of shell of Haliotis discus hannai grew from 36.3 mm to 66.1 mm in the 1 year old entities and from 60.6 mm to 66.1 mm for the 2 year old entities, while the weight of the meat increased from 3.16 g to 12.04 g and from 15.8 g to 21.5 g, respectively. The oxygen consumption and ammonia excretion rate displayed trend of increase in accordance with the increase in water temperature, while the feeding rate was high during the period from July to October. The assimilation rate was in the range of 68%-71% without significant difference between the age of the entities and seasons. SFG displayed +value throughout the year for the 1 year old entities of Haliotis discus hannai as well as for the 2 year old entities with the exception of the period of July, thereby showing that they are growing throughout the year. Therefore, there was no environmental effect including water temperature and salinity during the examination period.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.61-67
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• 2004

This study described relationships between fluctuation of fishing conditions for common squid and oceanic conditions in the East Sea from 1990 to 1999. Annual catches of common squid have been higher since the late 1980s compared to the period of the late 1970s to the mid-1980s. These catches fluctuations might be related to the effect of regime shifts. Monthly catches of common squid appear the timing of a large catch from September to December and a poor catch from March to May. The monthly catches are also the highest in October and are the lowest in April. Annual stable fishing grounds for coefficient of variation below 1.0 are formed in waters around Guryongpo and Ullung Island Based on optimum water temperature for catch, $16^{\circ}C$, optimum water depth for catch shallow going north. It indicates that the optimum water depth of fishing work different of each area Fishing ground formation and horizontal water temperature appear the minimum $10{\sim}14^{\circ}C$ in April, the maximum $10{\sim}20^{\circ}C$ in October. If seem, that seasonal fluctuation of fishing ground is related to the extension of the Tsushima warm current in the East Sea.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.2
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• pp.65-70
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• 2002

The previous studies showed that rumen microorganisms had an enhanced waste-degrading capability and controlling the dilution rate was very effective in improving acidification efficiency. Generally the composition of food waste has a small deviation value, but one of the waste components (grains, vegetables or meats) can be increased dramatically depending on a seasonal variation. Thus, it is important to evaluate the efficiency of acidogenic fermentation in this case. Each component was spiked to be 80% of the total waste in R1 (grains), R2(vegetables), and R3 (meats). In Rl, rapid degradation occurred during the initial two days. R2 showed similar performance to that of general food waste. In R3, degradation retarded in the initial stage and then increased after controlling the dilution rate. The acidification efficiencies of the reactors were 88.7 (R1), 73.5 (R2), and 62.1% (R3), respectively. Therefore, the fermentation efficiency was kept over 62% regardless of waste components, indicating that it was stable to acidify food waste by employing rumen microorganisms and controlling the dilution rate.