• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.285-291
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• 2010

To provide required flow rates of cooling or circulating water properly, approach flow conditions of vertical pump systems should be in compliance with state of the art acceptance criteria. The direct inflow should be vortex free, with low pre-rotation and symmetric velocity distribution. Physical model investigations are common practice and the best tool of prediction to evaluate, to optimize and to document flow conditions inside intake structures for vertical pumping systems. Optimization steps should be accomplished with respect to installation costs and complexity on site. The report shows evaluation of various approach flow conditions inside a compact waste water pumping station. The focus is on the occurrence of free surface vortices and the evaluation of air entrainment for various water level and flow rates. The presentation of the results includes the description of the investigated intake structure, occurring flow problems and final recommendations.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.7-12
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• 2001

A large number of methods for the design optimization have been proposed in recent years. However, it is not easy to apply these methods to practical use because of many iterations. So, in the design optimization, physical and engineering investigation of the given model are very important, which results in an overall increase in the optimization speed. This paper describes a novel optimization procedure utilizing the conformal transformation method. This approach consists of two phases and has the advantage of grasping the physical phenomena of the model easily. Some numerical results that demonstrate the validity of the proposed method are also presented.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.317-323
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• 2015

This study investigated the impact of the morphological change on a physical fish habitat in the downstream reach of a dam using long-term mobile bed simulation. The quasi-steady model was used for hydraulic simulation and the habitat suitability index model was applied for physical habitat simulation. For simulating long-term morphological change of the stream bed, The Exner equation was used. Sorting of bed material was also considered. The results of simulation showed that erosion and armoring process occurred in a reach downstream of the dam and change of physical habitat for Zacco platypus followed. These results indicate that channel morphology and substrate conditions effected the physical habitat for considering long-term investigation.

• Advances in nano research
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• v.14 no.2
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• pp.179-193
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• 2023

Physical activities enhance blood flow in the vessels, which may increase the quality of medicine delivery. The emergence of revolutionary technologies such as nanoscience, made it possible to treat the incurable illnesses such as cancer. This paper investigates the impact of sport and physical exercises on the quality and quantity of the drug-delivery based on the mathematical modeling of a nanomotor made by nanotubes carrying the nano-drug capsules. Accordingly, the mathematical equations of rotating nanomotor are generated by considering the both of higher-order beam model and nonlocal strain gradient model, as a comprehensive continuum theory. Next, through the generalized differential quadrature together with Newmark-beta methods, the differential relations are discretized and solved. Finally, the impact of varied parameters on the dynamical behavior of the nanomotor is examined in detail. The outcomes of this investigation can be useful to achieve an excellent design of nanomotors carrying nano-drugs.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1519-1528
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• 2018

The objective of the present study is the development of a comprehensive air chemical kinetic model that includes 11 species and 54 chemical reactions for the numerical investigation of air nonequilibrium inductively coupled plasmas. The two-dimensional, compressible Navier-Stokes equations coupled with the electromagnetic-field equations were employed to describe the fundamental characteristics of an inductive plasma. Dunn-Kangs 32 chemical-reaction model of air was reconstructed and used as a comparative model. The effects of the different chemical kinetic models on the flow field were analyzed and discussed at identical/different working pressures. The results theoretically indicate that no matter the working pressure is low or high, the use of the 54 chemical kinetic model presented in this study is a better choice for the numerical simulation of a nonequilibrium air ICP.

• Journal of Korea Water Resources Association
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• v.50 no.5
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• pp.325-334
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• 2017

In this study, the numerical investigation of the non-linear behavior of the fluid flow with physical properties, such as porosity and intrinsic permeability of a porous medium, and kinematic viscosity of a fluid, are carried out. The applied numerical model is ANSYS CFX which is the three-dimensional fluid dynamics model and this model is verified through the application of existing physical and numerical results. As a result of the verification, the results of the pressure gradient-velocity relationship and the friction coefficient-Reynolds number relationship produced from this study show relatively good agreement with those from existing physical and numerical experiments. As a result of the simulation by changing the porosity and intrinsic permeability of a porous medium and the kinematic viscosity of a fluid, the kinematic viscosity has the biggest effect on the non-linear behavior of the fluid flow in the porous medium.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3367-3382
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• 2023

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian computational fluid dynamics method that has been widely used in the analysis of physical phenomena characterized by large deformation or multi-phase flow analysis, including free surface. Despite the recent implementation of eddy-viscosity models in SPH methodology, sophisticated turbulent analysis using Lagrangian methodology has been limited due to the lack of computational performance and numerical consistency. In this study, we implement the standard and dynamic Smagorinsky model and dynamic Vreman model as sub-particle scale models based on a weakly compressible SPH solver. The large eddy simulation method is numerically identical to the spatial discretization method of smoothed particle dynamics, enabling the intuitive implementation of the turbulence model. Furthermore, there is no additional filtering process required for physical variables since the sub-grid scale filtering is inherently processed in the kernel interpolation. We simulate lid-driven flow under transition and turbulent conditions as a benchmark. The simulation results show that the dynamic Vreman model produces consistent results with experimental and numerical research regarding Reynolds averaged physical quantities and flow structure. Spectral analysis also confirms that it is possible to analyze turbulent eddies with a smaller length scale using the dynamic Vreman model with the same particle size.

• The Korean Journal of Franchise Management
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• v.8 no.4
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• pp.7-19
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• 2017

Purpose - The purpose of this study is to investigate the effect of model attractiveness on brand attitude and purchase intention, and examine whether product-model match-up plays a moderating role in the relationship between model attractiveness and brand attitude and purchase intention. The model attractiveness is consist of psychological and physical attractiveness of the model. The authors investigate how product-model match-up influence the strength of the relationship between model attractiveness - brand attitude and purchase intention. The purpose of this is to test whether product-model match-up influence the form and effectiveness of a model attractiveness on brand attitude and purchase intention and suggest the effective and efficient methods in the model selection strategies to increase advertising effectiveness based on the results of this study. Research design, data, and methodology - The experimental design for this study was the between subject design based on 2 group of the psychological attractiveness(high vs. low) × product-model match-up(high vs low) and 2 group of the physical attractiveness(high vs. low) × product-model match-up(high vs low). And a preliminary investigation was conducted to develop experimental stimuli through manipulation check to enhance the external validity of experimental research. The attractiveness of the model and product-model match-up are independent variables and manipulative variables in presentation of experimental stimuli. The self-administered methode experiment was conducted on 300 subjects in four groups constructed according to the independent variables. Result - The findings provide partial support for a moderator for product-model match-up on the model attractiveness - brand attitude and purchase intention. First, the influence of psychological attractiveness and physical attractiveness on brand attitude and purchase intention was shown significant. Also, it was found that the average value of brand attitude and purchase intention according to psychological attractiveness was significantly higher than the average value of brand attitude and purchase intention according to physical attractiveness in additional analysis. Second, the average value of brand attitude and purchase intention were higher when product - model match-up was high in both high and low psychological attractiveness and physical attractiveness of the model. However, in the case of psychological attractiveness, the correlation effect with product - model match-up was significant, but in the case of physical attractiveness, it was not significant. Conclusions - The results of this study suggest that the attractiveness factor should be considered in selecting the ad model by verifying the effect of the attractiveness of the model on the advertising effect. In particular, this study has great significance both academically and practically in terms of suggesting such implications that the advertising effect of psychological attractiveness and physical attractiveness may be different depending on the product type by additional analysis.

• Journal of the Korean earth science society
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• v.29 no.5
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• pp.419-427
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• 2008

The Galactic planetary nebulae emit many strong recombination and forbidden lines. By analyzing such lines, the physical condition of the planetary nebulae has been inferred using the strategically important diagnostic line ratios. In order to fully understand the physical condition of a planetary nebula and to derive its chemical abundances, the photoionization model codes, e.g., CLOUDY and NEBULA, were employed for an analysis of gaseous nebular spectra. For the well-studied, relatively simple planetary nebula NGC 7026, theoretical investigation was done with about the same input parameters in models. The predictions made by both codes seem to be in good accord. However, the predicted physical conditions, such as electron temperature and density, are slightly different. Especially, the electron temperatures are predicted to be higher in CLOUDY, which may cause a problem in chemical abundance determination. Our analysis shows that the main discordance may occur due to the diffuse radiation.

• Structural Engineering and Mechanics
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• v.81 no.3
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• pp.259-266
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• 2022

Based upon differential quadrature method (DQM) and nonlocal strain gradient theory (NSGT), an investigation on the free vibrations of 2D plate systems with nano-dimensions has been provided taking into account the effects of different mechanical loadings. In order to capture different mechanical loadings, a general form of variable compressive load applied in the axial direction of the plate system has been introduced. The studied plate has been constructed from two types of particles which results in graded material properties and nanoscale pores. The established formulation for the plate is in the context of a novel shear deformable model and the equations have been solved via a semi-numerical trend. Presented results indicate the prominence of material composition, nonlocal coefficient, strain gradient coefficient and boundary conditions on vibrational frequencies of nano-size plate.