• Journal of the Korean Chemical Society
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• v.64 no.3
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• pp.175-188
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• 2020

The purpose of this study was to analyze chemistry textbooks and teachers' guidebooks from the perspective of 'Ignorance', one of the important features of model. This is because the emphasis is on developing modeling capabilities for students in the 2015 Revised Curriculum. For this, Arrhenius model and Brønsted-Lowry model were selected as acid and base models in neutralization reaction which are important contents in chemistry curriculum. The analysis criteria of this study were extracted by analyzing previous studies and four general chemistry textbooks dealing with 'Ignorance' related to acid and base neutralization reaction. Based on the analysis criteria, we analyzed nine chemistry I textbooks and teacher's guides and six chemistry II textbooks and teacher's guides of the 2015 revised curriculum. In addition, we analyzed contents of four chemistry I textbooks and teacher's guides and three chemistry II textbooks and teacher's guides in the 2009 revised curriculum for comparison according to revised curriculums. We analyzed the contents related to the concept of 'neutralization reaction', 'neutrality', 'quantitative relation of neutralization reaction', 'degree of ionization', and 'ionization constant'. Based on the results of this study, we proposed a way to present 'Ignorance' of the models in teachers' guidebooks that chemistry teachers can understand 'Ignorance' of model and teach modeling capabilities for students.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.629-640
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• 2014

In this study, the applicability of dynamic water quality model to TMDL system was examined, methods for setting of water quality goal and estimation of allocation loads were suggested and results of applying these methods were analyzed. HSPF model was applied for Miho stream basin as a dynamic water quality model. The model was calibrated using measurement data obtained in 2009~2010 and showed satisfactory performance in predicting daily variations of flow rate and BOD concentration. Methods for TMDL application were categorized into 3 cases; water quality management (1) considering low flow condition(Case I), (2) considering entire period of the year (Case II) and (3) considering the worst water quality condition (Case III). BOD water quality goals at the end of Miho stream watershed increased in the order of Case IICase I>Case III. If further researches on base precipitation and method for model input of nonpoint source pollutant were carried out, water quality could be managed more reasonably and scientifically by applying dynamic water quality model to TMDL. The result of this study is expected to be used as primary data for TMDL using dynamic water quality model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.347-349
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• 2014

Model verification and validation (V&V) is a current research topic to build computational models with high predictive capability by addressing the general concepts, processes and statistical techniques. The hypothesis test for validity check is one of the model validation techniques and gives a guideline to evaluate the validity of a computational model when limited experimental data only exist due to restricted test resources (e.g., time and budget). The hypothesis test for validity check mainly employ Type I error, the risk of rejecting the valid computational model, for the validity evaluation since quantification of Type II error is not feasible for model validation. However, Type II error, the risk of accepting invalid computational model, should be importantly considered for an engineered products having high risk on predicted results. This paper proposes a technique named as the response-adaptive experimental design to reduce Type II error by adaptively designing experimental conditions for the validation experiment. A tire tread block problem and a numerical example are employed to show the effectiveness of the response-adaptive experimental design for the validity evaluation.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.1-7
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• 2015

The solid-phase extractant PS-D2EHPA/TBP was prepared by immobilizing two extractants D2EHPA and TBP in polysulfone (PS). The prepared PS-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal of Cu(II) from aqueous solution was investigated in batch system. The experiment data were obeyed the pseudo-second-order kinetic model. Equilibrium data were well fitted by Langmuir model and the removal capacity of Cu(II) by solid extractant PS-D2EHPA/TBP obtained from Langmuir model was 3.11 mg/g at 288 K. The removal capacity of Cu(II) was increased according to increasing pH from 2 to 6, but the removal capacity was decreased below pH 3 remarkably.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.841-849
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• 2015

The solid phase extractant SAN-D2EHPA/TBP containing two extractants of Di-(2-ethylhexyl)phosphoric acid (D2EHPA) and Tri-butyl-phosphate (TBP) was prepared by immobilizing two exractants D2EHPA and TBP in styrene acrylonitrile copolymer (SAN). The prepared SAN-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The solid phase extractant SAN-D2EHPA/TBP was tested for the removal of Cu(II) from aqueous solution. Experiments were carried out as a function of the pH and Cu(II) concentration in the aqueous phase. The equilibrium time was 180 min and equilibrium experiment data obeyed the pseudo-second-order kinetic model. The Langmuir isotherm model represented the experiment data as well. The maximum removal capacity of Cu(II) calculated from Langmuir isotherm model was 3.1 mg/g.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.27-36
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• 2007

Milled Korean pine (Pinus densiflora) wood was used to evaluate its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled woods were pretreated with 1N NaOH, 1N $NHO_3$, and distilled water, respectively, to examine the effect of pretreatment. Within the tested pH range in this study between 3 and 6, copper adsorption efficiency of NaOH-treated wood(96~99%) was superior than $NHO_3$-treated wood(19~31%) and distilled water-treated wood(18~35%). Adsorption behavior of copper onto both raw and $NHO_3$-treated woods was mainly attributed to interaction with carboxylic acid group. For NaOH-treated wood, carboxylate ion produced by hydrolysis was a major functional group responsible for Cu sorption. NaOH treatment of wood changed the ester and carboxylic acid groups into carboxylate group, whereas $NHO_3$ treatment did not affect the production of functional groups which could bind copper. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto NaOH-treated wood. A batch isotherm test using NaOH-treated wood showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.3
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• pp.205-213
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• 2019

Batch adsorption tests were performed to evaluate the applicability of adsorption kinetic model by using hydrogel chitosan bead crosslinked with glutaraldehyde (HCB-G) for Cu(II) as cation and/or phosphate as anion. Pseudo first and second order model were applied to determine the sorption kinetic property and intraparticle and Boyd equation were used to predict the diffusion of Cu(II) and phosphate at pore and boundary-layer, respectively. According to the value of theoretical and experimental uptake of Cu(II) and phosphate, pseudo second order is more suitable. On comparison with the value of adsorption rate constant (k), phosphate kinetic was 2-4 times faster than that of Cu(II) at any experimental condition indicating the electrostatic interaction between ${NH_3}^+$ and phosphate is dominated at the presence of single component. However, when Cu(II) and phosphate simultaneously exist, the value of k for phosphate was sharply decreased and then the difference was not significant. Both diffusion models confirmed that the sorption rate was controlled by film mass transfer at the beginning time (t < 3 hr) and pore diffusion at next time section (t > 6 hr).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.45-52
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• 2010

A model of the propulsion mechanism, I, II, III was based on a two-dimensional model of the Weis-Fogh mechanism and consisted of one or two wings in a square channel. The sailing and vibration performance characteristics of model ships were tested to compare with each other. we took results as follow. Thrust of propulsion model, I and III was increased by 31% and 43%, the speed of model ship by 20% and 23%, When compared to model II in same condition. The thrust improvement using the elastic spring wing was effective not only on all models but also in the real ship. The maximum amplitude and RMS were largest at the opening angle ${\alpha}=15^{\circ}$ and smallest at ${\alpha}=30^{\circ}$ on the vibration of model ship. The thrust of propulsion model III with opening angle ${\alpha}=30^{\circ}$, phase ${\Delta}T=0^{\circ}$ was large, but the amplitude of vibration was small relatively.

• Journal of Korea Water Resources Association
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• v.36 no.1
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• pp.61-74
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• 2003

This study(II) apply to the A city by using the optimal rehabilitation model based on the deterioration prediction of the water distribution system proposed the study(I). The deterioration prediction model divides factors into 14 factors with digging and experiment and 9 factor without digging and experiment and calculate the deterioration degree. The application results of the deterioration prediction model show that a difference of the deterioration degree according to factor numbers is within 1~2%. Also, the model can predict the deterioration degree of each pipe without digging and experiment. The optimal rehabilitation model is divided into the optimal residual durability of each deterioration factor and budget constraint or not. The application result is as follow: the rehabilitation time and cost increase according to the increasing of the optimal residual durability. When compared the model with budget constraint and model without budget constraint, the former model increase the cost of total contents. In case of budget constraint, the increasing tendency is concluded that the pipe rehabilitation is executed in same budget every year in condition that every rehabilitation cost do not exceed the every year budget within the optimal residual durability.

• Kyungpook Mathematical Journal
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• v.60 no.2
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• pp.319-334
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• 2020

We propose a mathematical model with Holling type II functional response, to study the dynamics of vaccination. In order to make our model more realistic, we have incorporated the recruitment of infected individuals as a continuous process. We have assumed that vaccination cannot be perfect and there is always a possibility of re-infection. We have obtained the existence of a disease free and endemic equilibrium point, when the recruitment of infective is not considered and also obtained the existence of at least one endemic equilibrium point when recruitment of infective is considered. We have proved that if R_v < 1, disease free equilibrium is locally asymptotically stable, which leads to the elimination of the disease from the population. The persistence of the model has also been established. Numerical simulations have been done to establish the results obtained.