• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.579-587
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• 2003

A lot of VOCs that is noxious ate exhausted at drying process of enamel coating device. This VOC gas can be incinerated perfectly through catalytic combustion, and heat that is occurred in incineration process ran be again used in drying process. By using VU catalytic combustion technology, in this study, we developed a enamel coating machine that have an excellent environment improvement and energy saying effect. As basic research for this development characteristics ana performance of catalytic combustion for VOC gas was evaluated and numerical analysis for drying oven was calculated. According to the result, VOCs combustion characteristics of metal form catalysis was excellent in high temperature, and it was seen that enamel coating machine should be designed as a precious controllable structure of recirculating supply rate and suction rate.

• Bulletin of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.40-46
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• 1996

함정설계지원시스템이란 함정 설계의 목표를 효율적으로 달성하기 위한 제반 기술적인 수단과 이들의 운용체제로, 함정 고유의 설계기술과 결합한 컴퓨터 이용기술의 집합체로 정의할 수 있다. 함정설계 및 건조에 있어서 컴퓨터기술의 이용은 아나로그 컴퓨터가 실용화되면서부터 활발하게 추진되기 시작하였다. 초기에는 주로 진동해석 및 제어시스템과 같은 여러가지 동적인 문제의 해결에 촛점이 맞추어져 왔다. 1960년대 초 컴퓨터 기술이 설계 분야에 이용되면서 선박의 설계 및 건조의 전 과정에 적용될 범용 컴퓨터 프로그램을 개발하기 위한 노력이 본격화되었으며, CAD tool이 상용화되기 전까지는 간단한 도형처리 기능을 포함한 특정 공학 해석을 신속하게 수행하기 위한 프로그램들이 개발, 사용되어 왔다. 컴퓨터 관련 기술이 발전함에 따라 함정설계지원시스템도 종래의 부분적인 설계업무의 자동화에서 함정의 획득(acquistion) 및 전 수명주기의 지원(life-cycle support) 과정에서의 생산성 향상, 품질향상 및 예산절감을 위한 수단으로 확대 발전되어 왔으며 최근에는 (CALS(Continuous Acquistion and Life-cycle Support)라는 새로운 문제로 정착되고 있다. 본 고에서는 21세기 대양해군을 지향하는 우리나라 해군력의 기본이 되는 함정의 설계, 건조 및 운용 지원분야의 획기적인 발전을 위해, 그 핵심적인 수단이 ㅗ딜 함정설계지원시스템의 개발동향에 대해 이 분야의 기술을 주도하고 있는 미 해군의 사례를 중심으로 살펴보고 현 단계에서 우리 해군이 추진가능한 몇가지 과제에 대해 제안하였다.

• Clean Technology
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• v.12 no.4
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• pp.217-223
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• 2006

The operating variables of a desorption step were experimentally investigated tor the cycle of the process made up of benzene adsorption, steam desorption, and drying step. The effect of adsorbent regeneration depending on existence and nonexistence of drying step was studied by breakthrough curves obtained in the adsorption step of the second cycle. The duration of drying step was determined by the experimental results. In case that the amount of nitrogen gas was fixed, the regeneration efficiency increased with the amount of steam. However, the effect of steam decreased as the amount of nitrogen increased. Therefore, it would be possible to predict the optimum amount of steam comparing the amount of nitrogen gas with amount of steam in economic view.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.255-264
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• 2009

To evaluate the effects of chemical pretreatments of lignocellulosic biomass on enzymatic hydrolysis process, Populus euramericana was pretreated for 1 hr with 1% sulfuric acid ($H_2SO_4$) at $150^{\circ}C$ and 1% sodium hydroxide (NaOH) at $160^{\circ}C$, respectively. Before the enzymatic hydrolysis, each pretreated sample was subjected to drying process and thus finally divided into four subgroups; dried or non-dried acid pretreated samples and dried or non-dried alkali pretreated samples and chemical and physical properties of them were analyzed. Biomass degradation by acid pretreatment was determined to 6% higher compared to alkali pretreatment. By the action of acid ca. 24.5% of biomass was dissolved into solution, while alkali degraded ca. 18.6% of biomass. However, reverse results were observed in delignification rates, in which alkali pretreatment released 2% more lignin fragment from biomass to the solution than acid pretreatment. Unexpectedly, samples after both pretreatments were determined to somewhat higher crystallinity than untreated samples. This result may be explained by selective disrupture of amorphous region in cellulose during pretreatments, thus the cellulose crystallinity seems to be accumulated in the pretreated samples. SEM images revealed that pretreated samples showed relative rough and partly cracked surfaces due to the decomposition of components, but the image of acid pretreated samples which were dried was similar to that of the control. In pore size distribution, dried acid pretreated samples were similar to the control, while that in alkali pretreated samples was gradually increased as pore diameter increased. The pore volume which increased by acid pretreatment rapidly decreased by drying process. Alkali pretreatment was much more effective on enzymatic digestibility than acid pretreatment. The sample after alkali pretreatment was enzymatically hydrolyzed up to 45.8%, while only 26.9% of acid pretreated sample was digested at the same condition. The high digestibility of the sample was also influenced to the yields of monomeric sugars during enzymatic hydrolysis. In addition, drying process of pretreated samples affected detrimentally not only to digestibility but also to the yields of monomeric sugars.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.461-470
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• 2019

This study was carried out to quantify the drought stress in grafted watermelon seedlings non-destructively by using chlorophyll fluorescence (CF) imaging technique rather than the visual judgment. Six-day old watermelon seedlings were grown under uniform irrigation for 3 days, and then given drought stress. Afterward, the sensor for the measurement of water content in plug tray cell unit was used to classify the drought-stress level into nine groups from D1 (53.0%, sufficient moisture state) to D9 (15.7%, extremely dry stress), and the 16 CF parameters were measured. In addition, re-irrigation was performed on the drought stressed seedlings(D5 - D9) to determine the growth and photosynthesis recovery level, which was not confirmed by visual judgment. The kinetic curve patterns of CF in three different drought stressed seedling groups were found to be different for the early detection of drought stress. All the 16 CF parameters decreased continuously with exposure to drought stress and drastically decreased from D5 (32.1%) where the visual judgment was possible. The fluorescence decline ratio (Rfd_Lss) started to decrease from the initial drought stress level (D5 - D6), and the Maximum PSII quantum yield (Fv/Fm) was significantly decreased in the later extreme drought stress range (D7 - D9) by re-irrigation recovery test. Thus, Rfd_Lss and Fv/Fm parameters were finally selected as potent indicators of growth and photosynthesis recovery in the initial and later stages of drought stress. Also, to the differences in the numerical values of the individual chlorophyll fluorescence parameters, the drought stress level was intuitively confirmed through the image. These results indicate that Rfd and Fv/Fm can be considered as potential CF parameters for the detection of low and extremely high drought stress, respectively. Furthermore, Fv/Fm can be considered as the best CF parameters for recovery at re-irrigation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.327-336
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• 2016

The Bagan, the central part of Myanmar, is dry zone where the mean annual precipitation is less than 600 mm for the last ten years. Forest in this region has been degraded due to biotic and abiotic disturbances. While there have been various efforts to rehabilitate the degraded area, the information on growth and physiological characteristics of planting species and the impacts of planting trees in the region still lacks. Therefore, this study was conducted to determine the growth and physiological water use efficiency characteristics of five species (Azadirachta indica A. Juss., Acacia catechu Willd., Eucalyptus camaldulensis Dehn., Acacia leucophloea (Roxb.) Willd. and Albizia lebbek (L.) Willd.) which are utilized as rehabilitation species in the dry zone and to identify the impacts of tree planting on microclimate change in dry zone. The growth and the foliar carbon isotope composition of seedlings and the above mentioned five species planted in 2005 were measured. And from February 2015 to January 2016, microclimatic factors air temperature and relative humidity at 60 cm and 2 m above soil, soil temperature, soil water contents and precipitation were measured at every 30-minute interval from the two weather stations installed in the plantation located in Ngalinpoke Mt. Range. One was established in the center of A. indica plantation, and the other was in the barren land fully exposed to the sunlight. Among the five species, A. indica and A. lebbek which showed higher water use efficiency could be recommended as rehabilitation species in dry zone. Planting trees in the dry area was shown to affect the change of microclimate with shading effects, declining temperature of the land surface and aridity of the air, and to contribute to conserving more water in soil by preventing direct evaporation and containing more water with fine roots of trees.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.88-91
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• 2014

In this study, oil as a source of biodiesel from Nannochloropsis oceanica was extracted using organic solvent. The oil extraction yield and efficiency from dry and wet microalgae were investigated. The initial fatty acids content of the N. oceanica was 317.8 mg/g cell showing a high oil content over 30%. The yield from dry microalgae was higher than that from wet microalgae due to the inhibition of water. The yield by chloroform-methanol was the highest and the yield by hexane was the lowest. However, the total fatty acids contents with the chloroform-methanol were 678.7 and 778.2 mg/g oil under dry and wet conditions, respectively. The high oil extraction yield by chloroform-methanol reflected the fact that the extracted oil contained a high level of impurity. The hexane-methanol extraction from dry N. oceanica showed high oil extraction efficiency, 82.6%. The chloroform-methanol extraction under wet condition also showed high efficiency, 88.0%. While the hexane-methanol extraction from dry microalgae is desirable under low drying cost, the chloroform-methanol extraction from wet microalgae is desirable under high drying cost.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.321-334
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• 2010

Objectives: The purpose of this study is to evaluate bonding efficacy by means of measuring the effect of remained solvent on Degree of conversion(DC) and ${\mu}TBS$ and FE-SEM examination. Materials and Methods: Two 2-step total etching adhesives and two single-step self etching adhesives were used in this study. First, volume weight loss of 4 dentin adhesives were measured using weighting machine in process of time in normal conditions and calculate degree of evaporation (DE). Reaction/reference intensity ratio were measured using micro-Raman spectroscopy and calculate DC according to DE. Then 2 experimental groups were prepared according to air-drying methods (under, over) and control group was prepared to manufacturer's instruction. Total 12 groups were evaluated by means of micro tensile bond strength and FE-SEM examination. Results: Degree of evaporation (DE) was increased as time elapsed but different features were observed according to the kind of solvents. Acetone based adhesive showed higher DE than ethanol and butanol based adhesive. Degree of conversion (DC) was increased according to DE except for $S^3$ bond. In ${\mu}TBS$ evaluation, bond strength was increased by additional air-drying. Large gaps and droplets were observed in acetone based adhesives by FE-SEM pictures. Conclusions: Additional air-drying is recommended for single-step self etching adhesive but careful consideration is required for 2-step total etching adhesive because of oxygen inhibition layer. Evaporation method is carefully chose and applied according to the solvent type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.660-667
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• 2018

This study examined the optimal manufacturing conditions of RDF using heat-dried sludge from sewage treatment plant in Cheonan with the oil-drying method. The amounts of oil evaporation and oil drying of the heat-dried sludge were measured at different temperatures to evaluate the value of the product. The performance of the product was then measured using a calorimeter and TGA. In addition, the concentration of odor, NH3, H2S, and TVOC during drying was determined using a portable odor-meter. Ingredient analysis was performed by EDS. Considering mass-production, the oil to heat-dried sludge weight ratio was fixed to 4:1. At $130^{\circ}C$, only physical mixing occurred after the instantaneous drying of internal water. Considering the eco-friendly aspects, there was no significant difference in the drying efficiency between $160^{\circ}C$ and $190^{\circ}C$. Therefore, the optimal conditions were a drying temperature of $160^{\circ}C$ within 5 minutes. Finally, the RDF manufactured in this study and fuel used in the thermal power plants were compared. The calorific value was 4,449kcal/kg, the water content was 2% and the ash content was 34%, which is higher than the fuel of thermal power plants. Therefore, it is believed that coal energy as well as wood pellets can be replaced.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.84-91
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• 2003

The effects of different dehydration conditions for the removal of ginkgo nut inner coat on peeled ginkgo nuts were examined using physical and sensory methods. Dehydration of ginkgo nuts at $90^{\circ}C$ for 120 min resulted in greater hardness, lightness (L), redness (a), yellowness (b), and firmness. Higher roasted flavor and larger holes were observed with dehydration at $150^{\circ}C$ for 30 min and greater cooked ginkgo flavor and green color with dehydration at $120^{\circ}C$ for 50 min. Based on these findings, dehydration at $120^{\circ}C$ for 50 min was determined as the adequate hot air dehydration condition for the removal of ginkgo nut inner coat. Ginkgo nuts stored at $25^{\circ}C$ maintained overall desirability up to 4 weeks. In ginkgo nuts stored at $4^{\circ}C$, all sensory desirabilities evaluated were reasonably high until 60 days of storage; desirability of appearance decreased moderately at 80 days of storage, and appearance became very undesirable at 180 days. Ginkgo nuts stored at $-18^{\circ}C$ showed little changes until 10 months of storage, but slight decreases in overall desirability, flavor, and texture were noted at 12 months.