• Macromolecular Research
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• 제11권1호
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• pp.53-61
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• 2003

A molecular-thermodynamic model is developed for the salt-induced protein precipitation. The protein molecules interact through four intermolecular potentials. An equation of state is derived based on the statistical mechanical perturbation theory with the modified Chiew's equation for the fluid phase, Young's equation for the solid phase as the reference system and a perturbation based on the protein-protein effective two body potential. The equation of state provides an expression for the chemical potential of the protein. In a single protein system, the phase separation is represented by fluid-fluid equilibria. The precipitation behaviors are simulated with the partition coefficient at various salt concentrations and degree of pre-aggregation effect for the protein particles. In a binary protein system, we regard the system as a fluid-solid phase equilibrium. At equilibrium, we compute the reduced osmotic pressure-composition diagram in the diverse protein size difference and salt concentrations.

• Carbon letters
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• 제22권
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• pp.14-24
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• 2017

Carboxylated multi-wall carbon nanotubes (MWCNTs-COOH) have been used as efficient adsorbents for the removal of picric acid from aqueous solutions under stirring and ultrasound conditions. Batch experiments were conducted to study the influence of the different parameters such as pH, amount of adsorbents, contact time and concentration of picric acid on the adsorption process. The kinetic data were fitted with pseudo-first order, pseudo-second-order, Elovich and intra-particle diffusion models. The kinetic studies were well described by the pseudo-second-order kinetic model for both methods. In addition, the adsorption isotherms of picric acid from aqueous solutions on the MWCNTs were investigated using six two-parameter models (Langmuir, Freundlich, Tempkin, Halsey, Harkins-Jura, Fowler-Guggenheim), four three-parameter models (Redlich-Peterson, Khan, Radke-Prausnitz, and Toth), two four-parameter equations (Fritz-Schlunder and Baudu) and one five-parameter equation (Fritz-Schlunder). Three error analysis methods, correlation coefficient, chi-square test and average relative errors, were applied to determine the best fit isotherm. The error analysis showed that the models with more than two parameters better described the picric acid sorption data compared to the two-parameter models. In particular, the Baudu equation provided the best model for the picric acid sorption data for both methods.

• 품질경영학회지
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• 제37권3호
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• pp.10-17
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• 2009

This study developed a new model for evaluating effects about the success of six sigma activities. This model consists of four constructs such as success of six sigma, employee's success experience, customer satisfaction, and business performance. Structural Equation Modeling (SEM) is used to analyze causality among the four constructs. Hypothesis were tested through a field study conducted for one hundred and thirty-one project leaders, who were asked to evaluate their experiences of six sigma projects. The results indicate that six hypothesis are statistically significant. As a result, the success of six sigma doesn't influence the customer satisfaction directly, but it influences customer satisfaction indirectly through employee's success experience. We find out that control for employee's success experience is important as well as success of six sigma in business innovation. Otherwise business performance is influenced directly by success of six sigma, that is business performance isn't influenced directly by employee's success experience but influenced indirectly through customer satisfaction. This study found that the change management raising employee's success experience is important in Six Sigma.

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.439-458
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• 2013

REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System) is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS) method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility). Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.

• 대한간호학회지
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• 제53권4호
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• pp.480-495
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• 2023

Purpose: This study aimed to develop and test a structural equation model on social re-adjustment of individuals with stroke based on a literature review and Roy's adaptation model. Methods: This study involved 321 participants who had a stroke and visited the outpatient department after discharge. The hypothetical model was developed based on Roy's adaptation model and a comprehensive review of previous literature on the topic. The model comprised four exogenous variables (neurological damage, gender [man], age, and social support) and five endogenous variables (activities of daily living, acceptance of disability, depression, rehabilitation motivation, and social re-adjustment). The data were analyzed using SPSS Windows software version 22.0 and AMOS 23.0. Results: Out of 28 research hypotheses, 18 were supported, and they indicated approximately 64% probability of social re-adjustment. Social re-adjustment is directly and significantly affected by age, social support, activities of daily living, and depression. Social re-adjustment is indirectly affected by neurological impairment, gender (men), age, social support, and rehabilitation motivation. Conclusion: Continuous assistance and care should be provided for individuals with disabilities caused by sudden neurological damage to facilitate gradual improvement in their social re-adjustment. To enhance social re-adjustment, especially among older adults, newly developed interventions should focus on improving their activities of daily living, preventing depression, and enhancing support from family and healthcare personnel.

• 대한영양사협회학술지
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• 제25권2호
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• pp.142-155
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• 2019

The aim of this study was to construct and test a structural equation model for the risk factors of metabolic syndrome in Korean adults. The structural equation model hypothesizes that eating alone and feeling depressed is a risk factor for metabolic syndrome. The data of this study were obtained from the Sixth Korea National Health and Nutrition Examination Survey which was cross-sectional data from the representative national survey. A total of 4,013 subjects replied to the survey item of lifestyle and completed the physical examinations among adults aged 19 years or older in South Korea was in 2015. The structural model in this study was composed of four latent variables: eating alone, depression, negative health behavior, and metabolic syndrome. Two variables, the rate of eating alone and depression, were exogenous variables. Negative health behavior was both a mediating variable and endogenous variable, and metabolic syndrome was the final endogenous variable. The data were analyzed using the Maximum Likelihood method and bootstrapping. The structural model was appropriate for the data based on the model fit indices. The results of this study can be summarized as follows: Eating alone is a direct risk factor of metabolic syndrome in Korean women. Depression can mediate metabolic syndrome through negative health behaviors. Negative health behavior had a direct impact on metabolic syndrome in both men and women. This study may be a guideline for interventions and strategies to reduce the incidence of metabolic syndrome in Korean adults.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.326-326
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• 2018

The study will assess the seasonal effect of hydrological models on performance and parameters for streamflow simulation. TPHM, GR4J, CAT, and TANK-SM hydrological models will be applied for simulating streamflow in ten small and large watersheds located in South Korea. The readily available hydrometeorological data will be applied as an input to the four hydrological models and the potential evapotranspiration will be computed using the Penman-Monteith equation. The SCE-UA algorithm implemented in PEST will be used to calibrate the models considering similar objective functions bedside the calibration will be renewed to capture the seasonal effects on the model performance and parameters. The seasonal effects on the model performance and parameters will be presented after assessing the four hydrologic models results. The conventional approach and season-based results will be evaluated for each model in the tested watersheds and a conclusion will be made based on the finding of the results.

• 여성건강간호학회지
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• 제7권2호
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• pp.141-156
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• 2001

The purpose of this study was to develop and test the structural model of a contraceptive behavior in Married Korean women. A hypothesis model was constructed on the basis of the health belief model, the theory of planned behavior and extensive literature review of contraception. The model was built by seven constructs. Four exogeneous variables included in the model were consisted of the contraceptive knowledges, the perceived threats, the sexual autonomy and the communication within a couple. Four endogenous variables were consisted of the attitudes toward contraception, the perceived control, the ability to plan a intercourse and the contraceptive behaviors. Empirical data for testing the hypothetical model were collected by the self report questionnaires from 243 Korean married women. The questionnaires used in this study were developed by this researcher and their Cronbach's alpha scores were ranged from .60 to .88. The collected data were analyzed by SPSS program(ver. 8.0) for descriptive statistical analysis and LISREL program(ver. 8.12a) for covariance structural analysis. On the basis of this results, it could be suggested that contraceptive behaviors be greatly affected by the perceived threats, the communications within couple, the attitudes toward contraception and the perceived control. Finally this model would be useful for the practice, theory and research of nursing.

• 수산해양기술연구
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• 제47권1호
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• pp.46-58
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• 2011

A steady-state analysis and a simple dynamic model as simplified methods are developed, and results of energy consumption loads are compared with results obtained using computer to evaluate the analytical solution. Before obtaining simplified model a mathematical model is formulated for the effect of wall mass on the thermal performance of four different houses having various wall construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. The steady state analysis that does not include the effect of thermal mass can provide an accurate estimate of energy consumption in most cases except for houses #2 and #4 in mild weather areas. This result shows that there is an effect of mass on the thermal performance of heavily constructed house in mild weather conditions. The simple dynamic model is applicable for high cycling rates and accurate values of inside wall temperature and ambient air temperature.

• 한국농공학회논문집
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• 제52권4호
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• pp.1-10
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• 2010

In this study, two estimation equations for preparing stream data for distributed storm runoff model were developed by analyzing the nonlinear relation between upstream flow-length and stream width, and between upstream flow-length and stream bed-slope. The equations for stream cell were tested in Chungjudam watershed (6,661 $km^2$) using KIMSTORM. Six storm events occurring between 2003 and 2008 were selected for the model calibration and verification before the test of equations. The average values of the Nash-Sutcliffe model efficiency (ME), the volume conservation index (VCI), the relative error of peak runoff rate (EQp), and the difference of time to peak runoff (DTp) were 0.929, 1.035, 0.037, and -0.406 hr for the calibrated four storm events and 0.956, 0.939, 0.055, and 0.729 hr for the two verified storm events respectively. The estimation equations were tested to the storm events, and compared the flood hydrograph. The test result showed that the estimation equation of stream width reduced the peak runoff and delaying the time to peak runoff, and the estimation equation of stream bed-slope showed the opposite results.