• Proceedings of the KIEE Conference
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.639-640
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• 2015

본 논문에서는 일간 시간대별 에너지저장장치 (Energy Storage System, ESS) 최적 충 방전량 스케줄링을 이용하여 계통연계형 마이크로그리드 내에 설치되는 ESS의 용량을 산정한다. 대상 마이크로그리드의 과거 부하데이터를 이용하여 절감하고자 하는 양을 정하고, 이를 이용하여 전력변환장치(Power Conditioning System, PCS)의 정격출력량을 산정한다. ESS용량의 기준점을 정하여 이분법 적용구간을 설정하고, 반복연산을 통해 최적 ESS용량을 찾는 과정을 제시한다.

• Journal of Biosystems Engineering
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• 제19권3호
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• pp.232-246
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• 1994

This study was conducted to develop the long-tenn storage method to minimize the black spot occurred on the surface of persimmons stored in the films at low temperature. The storage experiments were done with different films and persimmon varieties at $0^{\circ}C$ storage condition for 5 months, and then the physical and chemical characteristics of persimmons were tested monthly. The results were as follows : 1. The film 160 made from zeolites showed highest performance in well storings sweet persimmons for 5 months, compared with other films by eyesight. The initial moisture condensation inside the films seemed to cause the black spots on persimmons, and the effect of the film holes was never significant to prevent the black spots. 2. The sugar content was ranged from $14^{\circ}Brix$ to $15^{\circ}Brix$ regardless of film types and persimmom varieties, and it changed little for storage of 5 months. 3. The decrease rate of persimmom weight in the film 160 and 180 was 0.3% for storage of 5 months, while those in other films reached to 2%. The decrease rate of persimmon weight was least in the film 160 and 180. 4. The hardness of Fuyu least decreased in the films 160 and 380. It was changed from 36 kg/cnf to 8-27 $kg/cm^2$, and that of Charyang was from 31 $kg/cm^2$ to 8-10 $kg/cm^2$ for storage of 5 months. The hardness of Charyang rapidly decreased as storage period increased. 5. The average rate of black spot(defect rate) of Fuyu measured by a computer image processing system was least in the film 160 by 0.5%, but those in other films was ranged from about 5% to 20% for storage of 5 months. The rate of black spot of Charyang was less than that of Fuyu among most of films. 6. The intensity, hue, and saturation in persimmon color changed according to storage period. Especially, the intensity of persimmon colors decreased as storage period increased, but it was least in the film 160. 7. An integrated long-term storage method of sweet persimmons was suggested in the basis of the experiments and literature reviews.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.555-560
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• 2018

The high temperature stability of a chloride mixture, $NaCl-KCl-ZnCl_2$ (NaKZn-Chloride), is investigated to evaluate its potential as a thermal storage material. A thermal storage media should maintain a stable thermal properties within the temperature range of heat storage. Results from an a priori experiment showed that the NaKZn-chloride is stable only up the much lower temperature, while its stability limit is reported to be $850^{\circ}C$ in the literature. This study aims to investigate if the thermal property is changed by the moisture absorbed in the heat storage material. The effect of moisture content on the thermal properties was measured. The results show that the melting point remains the same regardless of the amount of moisture absorbed. Meanwhile, the high temperature stability is lower for the moisture treated samples. The results of this work infer that the loss of a hygroscopic thermal storage media can be reduced by avoiding its contacts to moisture in designing high temperature thermal storage systems.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.595-603
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• 2012

International Thermonuclear Experimental Reactor (ITER) will be constructed in 2019 according to the JIA (Joint Implementation Agreement) of 7 countries. The ITER fusion fuel cycle consists of fusion vacuum vessel, tritium plant and fuelling system. The tritium plant provides the functions of storage, delivery, separation, removal and recovery of the deuterium and tritium used as fusion fuels for the ITER. The tritium plant systems supply deuterium and tritium from external sources and treat all tritiated fluids from ITER operation through Storage and Delivery System (SDS), Tokamak Exhaust Processing (TEP), Isotope Separation System (ISS), Water Detritiation System & Atmosphere Detritiation System (WDS & ADS) and Analysis System (ANS). In this paper, the functions and design requirements of the major systems in the tritium plant and the status of R&D are described. Korean party is developing the SDS for ITER tritium plant and partially attaining the WDS technology through the construction and operation experience of the Wolsong Tritium Removal Facility (WTRF). Now it is expected that researchers in other fields such as chemical engineering take part in the development of upcoming technologies for ISS and TEP.

• Journal of the Korean institute of surface engineering
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• 제56권6호
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• pp.341-352
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• 2023

This paper reviews the potentials of a rotary chemical vapor deposition (RCVD) process for nanomaterial synthesis and coating on powder-based materials. The rotary reactor offers a significant improvement over traditional CVD methods having horizontal and fixed reaction chambers. The RCVD system yields enhanced productivity and surface coating uniformity of nanoparticles applied in various purposes, such as efficient heat dissipation, surface hardness enhancement, and enhanced energy storage performances. The effectiveness of the RCVD system would open up new possibilities in various applications because uniform coating on powder-based materials with massive productivity is inevitable to develop multi-functional materials with high reliability.

• Journal of Hydrogen and New Energy
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• 제19권4호
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• pp.299-304
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• 2008

Thermal decomposition of Ammonia Borane have been investigated with various analytical methods including TGA, TP-MS, DSC. By-products such as aminoborane and borazine were identified during hydrogen release by TGA, TP-MS analysis. $H_2$ release amount was measured at each temperature isothermally, which resulted in 7 wt% $H_2$ release at 130$^{\circ}C$. Moreover, higher temperature enhanced hydrogen release kinetics leading to shortened induction period from 20 min at 95$^{\circ}C$ to 0 min at 130$^{\circ}C$. Melting and decomposition at close temperature (4$^{\circ}C$ difference) caused the formation of thin foam during hydrogen release. Suppression of by-products and thin foam formation during hydrogen release is suggested as critical issues to realize chemical hydrogen storage system with ammonia borane.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
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• pp.192.1-192
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• 2003

The aim of this study was to develop a model that could be used in the design of modified atmosphere packaging (MAP) for Mandarin oranges. Respiratory data at 5, 10, 20$^{\circ}C$ for mandarin oranges were gathered and altered for create useful respiration model. The maximum rate of oxygen uptake increased with increasing temperature. The packaging materials were conventional low density polyethylene and polypropylene with anti-fog, and anti-fungi treatments, and thickness was 30 $\mu\textrm{m}$ and 50 $\mu\textrm{m}$. Permeability tests were performed to find their oxygen, carbon dioxide, water vapor transmission rate as increases in temperature. Test results were then converted to logarithm format for MAP modeling. Optimum gas composition in the package system for fruits were set according to literature and upper or lower limits of oxygen and dioxide established. To predict gas composition at certain storage time, weight of fruits, film thickness, film type, and other variables, respiration rate was studied at various storage conditions. The validity of the model was tested experimentally by observing actual atmospheric changes inside packages. It is concluded that the strategy developed is of use in designing dynamic gas exchange MAP systems, and also has potential uses in similar agricultural products.

• Journal of the Korean Society of Safety
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• 제33권5호
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• pp.141-149
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• 2018

In a PCB factory, there is a corrosive chemical substance supply system that can causes major leakage accidents. These accidents can give rise to shut down the factory and do residents damage that cause enormous loss of properties. To mitigate these risks, it is necessary to provide a chemical disaster prevention system. Moreover, after considering the situation and environment of the production site, it is of great importance to build an optimal chemical accident prevention system by reflecting risk reduction measures from the point of process design and by assessing quantitative risk based on reliability data. However, because there was no established database of the reliability about facilities and equipment that can be used in the domestic, the business site and consulting organization had being used the reliability data such as USA CCPS(Center for Chemical Process Safety). In these days, Korean institutes are studying on reliability data utilization method of quantitative risk assessment for preventing chemical accidents and domestic utilization algorithms and storage bed of reliability data. This study presents samples of reliability database about the chemical substance supply system that constructed from the history data such as failure, maintenance for 10 years at a PCB factory. Also, this work proposes the safety design criteria for supply facilities of corrosive chemical substance by assessing quantitative risk on the basis of the reliability data.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.110-113
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• 2002

Statistical- based, principal component analysis (PCA) was applied to chemical data from two underground storage systems containing LPG to assess the usefulness of such technique at the initial stage (Pyeongtaek) or middle stage (Ulsan) of hydrochemical studies. For the first case, both natural and anthropogenic contamination characterize regional groundwater. Saline water buffered by Namyang lake affects as a natural factor, whereas cement grouting influence as an artificial factor. For the second study area, contaminations due to operation of LPG caverns, such as disinfection activity and cement grouting effect, deteriorate groundwater quality. This study indicates that principal component analysis would be particularly useful for summarizing large data set for the purpose of subsurface characterization, assessing their vulnerability to contamination and protecting recharge zones.

• Journal of Institute of Control, Robotics and Systems
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• 제22권12호
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• pp.1040-1045
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• 2016

An inventory control system was developed for multiproduct batch plants with an arbitrary number of batch processes and storage units. Customer orders are received by the plant at intervals and in quantities that are subject to random fluctuations. The objective of the plant operation is to minimize the total cost while maintaining inventory levels within the storage or warehouse capacity by adjusting the startup times, the quantities of raw material orders, and production batch sizes. An adaptive model-based control algorithm was developed that uses a periodic square wave model to represent the flows of material between the processes and the storage units. The effectiveness of this approach was demonstrated by performing simulations.