• 상하수도학회지
• /
• 제27권6호
• /
• pp.771-778
• /
• 2013

Gas hydrate (GH) process is a new desalination technology, where GH is a non- stoichiometric crystalline inclusion compounds formed by water and a number of gas molecules. Seawater GH is produced in a low temperature and a high pressure condition and they are separated from the concentrated seawater. The drawback of the GH process so far is that salt contents contained in its product does not meet the fresh water quality standard. This means that the GH process is not a standalone process for seawater desalination and it needs the help of other desalting process like reverse osmosis (RO). The objective of this study is to investigate the effect of GH process on energy saving for RO process in seawater desalination. The GH product water quality data, which were obtained from a literature, were used as input data for RO process simulation. The simulation results show that the energy saving effect by the GH process is in a range of 68 % to 81 %, which increases as the salt removal efficiency of the GH process increases. Boron (B) and total dissolved solids (TDS) concentrations of the final product of the hybrid process of GH and RO were also investigated through the RO process simulation to find relavant salt rejection efficiency of the GH process. In conclusion, the salt rejection efficiency of the GH process should exceed at least 78% in order to meet the product water quality standards and to increase the energy saving effect.

• 반도체디스플레이기술학회지
• /
• 제18권1호
• /
• pp.5-9
• /
• 2019

Optical emission spectroscopy is used to identify chemical species and monitor the changes of process results during the plasma process. However, plasma process monitoring or fault detection by using emission signal variation monitoring is vulnerable to background signal fluctuations. IR heaters are used in semiconductor manufacturing chambers where high temperature uniformity and fast response are required. During the process, the IR lamp output fluctuates to maintain a stable process temperature. This IR signal fluctuation reacts as a background signal fluctuation to the spectrometer. In this research, we evaluate the effect of infrared background signal fluctuation on plasma process monitoring and improve the plasma process monitoring accuracy by using simple infrared background signal subtraction method. The effect of infrared background signal fluctuation on plasma process monitoring was evaluated on $SiO_2$ PECVD process. Comparing the $SiO_2$ film thickness and the measured emission line intensity from the by-product molecules, the effect of infrared background signal on plasma process monitoring and the necessity of background signal subtraction method were confirmed.

• 한국환경과학회지
• /
• 제23권3호
• /
• pp.369-378
• /
• 2014

Effect of improvement of the dielectric barrier discharge (DBD) plasma system on the inactivation performance of bacteria were investigated. The improvement of plasma reactor was performed by combination with the basic plasma reactor and UV process or combination with the basic plasma reactor and circulation system which was equipped with gas-liquid mixer. Experimental results showed that tailing effect was appeared after the exponential decrease in basic plasma reactor. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of basic plasma process and UV process. The application of gas-liquid mixing device on the basic plasma reactor reduced inactivation time and led to complete sterilization. The effect existence of gas-liquid mixing device, voltage, air flow rate (1 ~ 5 L/min), water circulation rate (2.8 ~ 9.4 L/min) in gas-liquid mixing plasma, plasma voltage and UV power of gas-liquid mixing plasma+UV process were evaluated. The optimum air flow rate, water circulation rate, voltage of gas-liquid mixing system were 3 L/min, 3.5 L/min and 60 V, respectively. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of gas-liquid mixing plasma and UV process.

• 경영과학
• /
• 제27권3호
• /
• pp.99-115
• /
• 2010

We classified quality management practices of manufacturing companies into 'Infra' factor and 'Process' factor which were introduced based on existing literatures and previous studies related to quality management. It was our first objective to confirm its conformance in Korean manufacturing industry, and to examine the two factors effect positively on production performance. Moreover, we tried to examine whether JIT and workforce management have an moderate effect on 'Infra and Process factors-performance' relationship, using moderate regression. As the result of empirical study on nationwide manufacturing companies, we had the results that the classification between Infra factor and Process factor in quality management practices was valid in Korean manufacturing companies, and that the two factors gave performances positive effect. Moreover, our secondary analysis showed that JIT had an positive moderate effect on the Infra factor while workforce management on the Process factor. With these results, we have an interpretation that manufacturing companies which aim to enhance short term performances have to concentrate their effort and investment on Process factor and, on the other hand, ones which aims to improve long term performances on Infra factor.

• 한국기계가공학회지
• /
• 제7권3호
• /
• pp.61-66
• /
• 2008

For the production of urethane prepolymer, the effect of process parameters such as diisocyanate MDI and polyol TDI was tested. In this paper, design of experiments has been adopted for studying the effect of the process parameters on the improvement of NCO and viscosity of pre-polymer. As a result of comparison of different parameters, the effect of polyol was stronger than that of isocyanate in comparison of reactivity according to the amounts of isocyanate and polyol. Especially, NCO and viscosity of pre-polymer affected a product safety.

• 반도체디스플레이기술학회지
• /
• 제12권4호
• /
• pp.9-13
• /
• 2013

Lapping is a very complicated and random process resulting from the variation of abrasive grains in its sizes and shapes and from the numerous factors having an effect on the process quality. This paper presents a study of a $2^4$ full factorial experimental design and analysis to optimize surface quality in lapping operation. The optimization of the factors to obtain minimum surface roughness was carried out by incorporating effect plots, main effect plots, interaction plots, analysis of variance(ANOVA), surface plots, and contour plots. The statistical design experiments, designed to reduce the total number of experiments required, indicated that, within the selected conditions, all the parameters influenced at a significance level of 5%. In addition, some of the possible interactions between these parameters also influenced the lapping process, especially those that were of third order. A regression model was suggested and fitted the experimental data very well.

• 복식
• /
• 제52권3호
• /
• pp.99-109
• /
• 2002

The purpose of 7his study was to understand the characteristic of involvement which affect to consumers of fashion market, and at the viewpoint of complex style, this involvement is consists of clothing involvement, advertising involvement and situation involvement, also by verifying the consumers reaction to clothing advertising effect process. It analyzed at last six hundred eighteen women in the age of twenty to thirty yearn old who live in Seoul. SPSS package were used to analyze the gathered data. Frequency, percentage, fator analysis. ANOVA. duncan test, correlation analysis. The results of this study can be summarized as follows : First, The clothing involvement was the highest Involvement of fashion consumers and it showed high correlation among clothing involvement, advertising involvement, situation involvement. Second, Depends on the nature of involvement, involvement group is divided as the most involvement, high involvement, low Involvement and the most lowest involvement groups. Third, Involvement and advertising effect showed highly difference, and the higher involvement group has high perceptive process and memory progress, friendly attitude process, and purchasing intention is high.

• 한국환경과학회지
• /
• 제28권3호
• /
• pp.291-301
• /
• 2019

This study was conducted to investigate the effect of salt concentration and turbidity on the inactivation of Artemia sp. by electrolysis, UV photolysis, electrolysis+UV process to treat ballast water in the presence of brackish water or muddy water caused by rainfall. The inactivation at different salt concentrations (30 g/L and 3 g/L) and turbidity levels (0, 156, 779 NTU) was compared. A decrease in salt concentration reduced RNO (OH radical generation index) degradation and TRO (Total Residual Oxidant) production, indicating that a longer electrolysis time is required to achieve a 100% inactivation rate in electrolysis process. In the UV process, the higher turbidity results in lower UV transmittance and lower inactivation efficiency of Artemia sp. Higher the turbidity resulted in lower ultraviolet transmittance in the UV process and lower inactivation efficiency of Artemia sp. A UV exposure time of over 30 seconds was required for 100% inactivation. Factors affecting inactivation efficiency of Artemia sp. in low salt concentration are in the order: electrolysis+UV > electrolysis > UV process. In the case of electrolysis+UV process, TRO is lower than the electrolysis process, but RNO is more decomposed, indicating that the OH radical has a greater effect on the inactivation effect. In low salt concentrations and high turbidity conditions, factors affecting Artemia sp. inactivation were in the order electrolysis > electrolysis+UV > UV process. When the salt concentration is low and the turbidity is high, the electrolysis process is affected by the salt concentration and the UV process is affected by turbidity. Therefore, the synergy due to the combination of the electrolysis process and the UV process was small, and the inactivation was lower than that of the single electrolysis process only affected by the salt concentration.

• 한국환경과학회지
• /
• 제18권6호
• /
• pp.667-674
• /
• 2009

This study has carried out to evaluate the effect of NaCI as electrolyte of single (electrolysis and UV process) and complex (electrolysis/UV) processes for the purpose of removal and mineralization of Rhodamine B (RhB) dye in water. It also evaluated the synergetic effect on the combination of electrolysis and UV process. The experimental results showed that RhB removal of UV process was decreased with increase of NaCl, while RhB removal of electrolysis and electrolysis/UV process was increased with increase of NaCI. The decolorization rate of the RhB solution in every process was more rapid than the mineralization rate identified by COD removal. The latter took longer time for further oxidation. Absorption spectra of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the bulk solution: concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the breakup of the chromophores. It was observed that RhB removal in electrolysis/UV process is similar to the sum of the UV and electrolysis. However, it was found that the COD of RhB could be degraded more efficiently by the electrolysis/UV process than the sum of the two individual process. A synergetic effect was demonstrated in electrolysis/UV process.

• 산업경영시스템학회지
• /
• 제38권1호
• /
• pp.101-109
• /
• 2015

This paper suggests a procedure to define business process improvement (BPI) projects with analysis results based on the cause-and-effect chain. The procedure developed in this paper focuses on eliminating root causes of business problems resulted from abnormal events occurred in business process executions. First, we develop three criteria used to make clusters of the root causes where a cluster of root causes will be eliminated together by a BPI project defined based on the cluster. Second, we develop a method to formulate desired expectations from the BPI project. Also, we suggest a method to calculate the relative importance of the BPI projects that help a BPI organization determine priorities of them. We illustrate the procedure and the methods with some examples for the domestic mail delivery process in the postal service industry.