• Membrane and Water Treatment
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• 제1권1호
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• pp.13-37
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• 2010

The performance of an electrodialyzer for concentrating seawater is predicted by means of a computer simulation, which includes the following five steps; Step 1 mass transport; Step 2 current density distribution; Step 3 cell voltage; Step 4 NaCl concentration in a concentrated solution and energy consumption; Step 5 limiting current density. The program is developed on the basis of the following assumption; (1) Solution leakage and electric current leakage in an electrodialyzer are negligible. (2) Direct current electric resistance of a membrane includes the electric resistance of a boundary layer formed on the desalting surface of the membrane due to concentration polarization. (3) Frequency distribution of solution velocity ratio in desalting cells is equated by the normal distribution. (4) Current density i at x distant from the inlets of desalting cells is approximated by the quadratic equation. (5) Voltage difference between the electrodes at the entrance of desalting cells is equal to the value at the exits. (6) Limiting current density of an electrodialyzer is defined as average current density applied to an electrodialyzer when current density reaches the limit of an ion exchange membrane at the outlet of a desalting cell in which linear velocity and electrolyte concentration are the least. (7) Concentrated solutions are extracted from concentrating cells to the outside of the process. The validity of the computer simulation model is demonstrated by comparing the computed results with the performance of electrodialyzers operating in salt-manufacturing plants. The model makes it possible to discuss optimum specifications and operating conditions of a practical-scale electrodialyzer.

• Membrane and Water Treatment
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• 제2권3호
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• pp.187-205
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• 2011

The electric transport of the mixture of hydrochloric and phosphoric acids through strong base (Neosepta ACM) and weak base (Selemion AAV) anion-exchange membranes was investigated. The instantaneous efficiency of HCl removal from the cathode solution, $CE_{Cl}$, with and without $H_3PO_4$ was determined. It was found that $CE_{Cl}$ was 0.8-0.9 if the number of moles of elementary charge passed through the system, $n_F$, did not exceed ca. 80% of the initial number of HCl moles in the cathode solution, $n_{Cl,ca,0}$. The retention efficiency of $H_3PO_4$ in that range was close to one. The transport of acid mixtures was satisfactorily described by a model based on the extended Nernst-Planck and Donnan equations for $n_F$ not exceeding $n_{Cl,ca,0}$. Among the tested model parameters, most important were: concentration of fixed charges, the porosity-tortuosity coefficient, and the partition coefficient of an undissociated form of $H_3PO_4$. For the both membranes, the obtained optimal values of fixed charge concentration, $\bar{c}_m$, were up to 40% lower than the literature values of $\bar{c}_m$ obtained from the equilibrium measurements. Regarding the $H_3PO_4$ equilibria, it was sufficient to consider $H_3PO_4$ as a monoprotic acid.

• 유통과학연구
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• 제13권11호
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• pp.23-30
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• 2015

Purpose - Small- and medium-sized enterprises often rely on the owner's personal characteristics. This study aims to verify the impact of the awareness of such a business leader's sincerity and the sincerity of their leader-member exchange (LMX) on employee psychological ownership and organizational commitment. The findings offer clues to how small- and medium-sized company leaders should engage with employees. Research design, data, and methodology - A total of 289 valid questionnaires were examined using frequency, descriptive statistics, and correlation analyses and structured equation modeling. Results - Authentic leadership and LMX were both found to have a positive impact on each trust factor, each trust factor had a positive impact on psychological ownership and organizational commitment, and psychological ownership had a positive impact on organizational commitment. Conclusion - These results suggest that small- and medium-size company leaders should use self-awareness and self-regulation to encourage the recognition of their sincerity, and strive to achieve a positive relationship with employees. It also suggests that leaders should improve trust between employees and establish various strategies to enable employee psychological ownership.

• 한국정보시스템학회지:정보시스템연구
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• 제28권4호
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• pp.105-129
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• 2019

Purpose Issues related to information security have been a crucial topic of interest to researchers and practitioners in the IT/IS field. This study develops a research model based on a Structure-Conduct-Outcome (SCO) framework for the social exchange relationship between employees and organizations regarding information security. Design/methodology/approach In applying an SCO framework to information security, structure and conduct are activities imposed on employees within an organizational context; outcomes are activities that protect information security from an employee. Data were collected from 438 employees working in manufacturing and service firms currently implementing an information security policy in South Korea. Structural equation modeling (SEM) with AMOS 22.0 is used to test the validation of the measurement model and the proposed casual relationships in the research model. Findings The results demonstrate support for the relationships between predicting variables in organization structure (security policy and physical security system) and the outcome variables in organization conduct (top management support, security education program, and security visibility). Results confirm that the three variables in organization conduct had a positive effect on individual outcome (security knowledge and compliance intention).

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.1-11
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• 2007

본 연구는 NPK(질소-인-칼슘) 비료 생산을 위하여 강양이온 이온교환수지를 사용하는 모사이동층(SMB; simulated moving bed) 흡착 공정의 모델링과 모사에 관하여 다룬다. 이 공정은 생산부와 재생부로 크게 나뉘며, 원하지 않는 이온을 제외시키기 위한 2개의 세척 구역을 포함하여 6개의 구역으로 구성되어있다. 따라서 전통적인 4구역 모사이동층 공정보다 좀 더 복잡한 운전 조건을 갖는다. 이러한 6구역 모사이동층 공정의 모델링과 모사를 통하여 얻은 결과는 파일럿규모의 공정과 상용화 공정에서 얻은 실험 결과와 유사함을 보여주었다. 실험 결과로부터 확인된 이 모델식은 최적 운전 조건을 얻기 위한 최적화 문제에 적용될 수 있을 것이다.

• 동아시아경상학회지
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• 제4권4호
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• pp.1-7
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• 2016

This paper has studied the impacts of the exchange rate, government debt as a percent of GDP and other relevant macroeconomic variables on aggregate output in the Philippines. A simultaneous-equation model consisting of aggregate demand and short-run aggregate supply is applied. The dummy variable technique is employed to detect whether the slope and intercept of the real effective exchange rate may have changed. Real depreciation during 1998.Q1 - 2006.Q3, real appreciation during 2006.Q4 - 2016.Q1, a lower domestic debt as a percent of GDP, a lower real interest rate, a higher stock price or a higher lagged real oil price would raise aggregate output. Recent trends of real peso appreciation, declining domestic debt as a percent of GDP, lower real interest rates, and rising stock prices are in line with the empirical results and would promote economic growth. The authorities may need to continue to pursue fiscal prudence and maintain a stronger peso as the positive effect of real appreciation dominates its negative effect in recent years.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.209-216
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• 2021

This study aim is to examine 1) the impact of corporate social responsibility disclosure and tax aggressiveness on firm value, 2) the impact of tax aggressiveness on firm value, and 3) the impact of corporate social responsibility on firm value. The sample of this study is 29 manufacturing companies listed on the Indonesia Stock Exchange. The period of research spans three years, from 2017 to 2019. The data is gathered from the annual report of the companies or website of companies and also the website from Indonesia Stock Exchange (IDX). This study uses Structural Equation Model with Partial Least Square. The research findings show that corporate social responsibility and tax aggressiveness have a negative and significant impact on firm value. The tax aggressiveness and firm value have a negative and significant impact. Corporate social responsibility has a positive and significant impact on firm value. This study uses the manufacturing sector, so that the findings of this study cannot be generalized to other sectors. Future research should explore other sectors such as mining, banking, etc. This study uses Effective Tax Rate (ETR) to measure tax aggressiveness. Further research should use another measurement, for instance, Current Effective Tax Rate (CETR).

• The Journal of Asian Finance, Economics and Business
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• 제10권1호
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• pp.9-17
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• 2023

The study attempted to answer the questions related to the expected effects of supply chain management variables which include: Partnership with Suppliers (PS), Relationships with Customers (RC), Quality of Information Exchange (QIE), and Postponement (P), as independent variables, total quality management (TQM) as a dependents variable, and just in time (JIT) as a mediator variable. The study relies on the descriptive approach by conducting an empirical study on commercial companies in Riyadh Governorate in the Kingdom of Saudi Arabia. Through the methods of descriptive and analytical statistics represented in exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modeling (SEM)), using the AMOS and SPSS programs, the results of the applied study indicated that: There is an effect of supply chain management variables (quality of information exchange, Postponement) on just in time (JIT), there is no effect of the supply chain variables (relationship with customers, partnership with suppliers) on just in time (JIT), there is an indirect effect of the quality of information exchange, Postponement, partnership with suppliers, the relationship with customers on total quality management (TQM), relationship with customers affect on total quality management (TQM) indirectly, just in time (JIT) does not affect total quality management (TQM)

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.21-30
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• 1998

A theoretical model was developed to evaluate the effects of soil and airflow characteristics on the soil-air heat exchanger performances. The model, which includes three-dimensional transient energy and mass equilibrium-equation, was solved by using a computer program that uses Finite Difference Methods and Gauss-Seidel iteration computation. Energy gains, heat exchange efficiencies, and outlet air temperature are presented including the effects of soil moisture content, soil conductivity, soil thermal diffusivity, and soil initial temperature. Also, data related to the effects of airflow rate and inlet air temperature on the thermal performance of the system are presented. The results indicated that energy gains depend on soil conductivity, soil thermal diffusivity, and soil initial temperature. Heat exchange efficiencies relied on air mass flow rate and soil moisture content.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1601-1606
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• 2004

In this paper, the unsteady behavior of the viscous flow field past an impulsively started elliptic cylinder is studied numerically. In order to analyze flow field, we introduce vortex particle method. The vorticity transport equation is solved by fractional step algorithm which splits into convection term and diffusion term. The convection term is calculated with Biot-Savart law, the no-through boundary condition is employed on solid boundaries. The diffusion term is modified based on the scheme of particle strength exchange. The particle redistributed scheme for general geometry is adapted. The flows around an elliptic cylinder are investigated for various attack angles at Reynolds number 200. The comparison between numerical results of present study and experimental data shows good agreements.