• Advances in materials Research
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• v.9 no.2
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• pp.99-107
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• 2020

Reinforced aluminum alloy base composites have become increasingly popular for engineering applications, since they usually possess several desirable properties. Recently, Warm Accumulative Roll Bonding (WARB) process has been used as a new novel process to fabricate particle reinforced metal matrix composites. In the present study, TiO₂ particles are used as reinforcement in aluminum metal matrix composites fabricated through warm accumulative roll bonding process. Firstly, the raw aluminum alloy 1060 strips with TiO₂ as reinforcement particle were roll bonded to four accumulative rolling cycles by preheating for 5 min at 300℃before each cycle. The mechanical and bonding properties of composites have been studied versus different volume contents of TiO₂ particles by tensile test, peeling test and vickers micro-hardness test. Moreover, the fracture surface and peeling surface of samples after the tensile test and peeling test have been studied versus different amount of TiO₂ volume contents by scanning electron microscopy. The results indicated that the strength and the average vickers micro-hardness of composites improved by increasing the volume content of TiO₂ particles and the amount of their elongation and bonding strength decreased significantly.

• Journal of Drive and Control
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• v.21 no.2
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• pp.15-22
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• 2024

The objective of this study was to examine whether a gerotor pump used in a transmission could be converted into an electric vehicle thermal management system pump using a virtual design environment. To achieve this objective, we first built an environment that could analyze the performance of a gerotor pump in heat transfer fluid. Flow rate, pressure, and volumetric efficiency were then analyzed when using heat transfer fluid in a gerotor pump. Finally, how large the displacement volume of the pump should be designed when using a heat transfer fluid other than oil was determined. Based on results of this study, it is expected that gerotor pumps will be applied to new business fields such as electric vehicle cooling systems.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.55-58
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• 2019

This study was performed to examine the visualization and anatomical variants of the hepatic artery with dual-phase computed tomography (CT) angiography and three-dimensional volume rendering imaging analysis in clinically normal dogs. Seven healthy beagle dogs were enrolled and underwent dual CT angiography. Arterial phase images could be obtained with multi-detector CT angiography using the fixed-scan method in these dogs. Contrast enhancement of the hepatic parenchyma was quite minimal because of the unique blood supply system of the liver. In most dogs, the main hepatic arterial branches were the right lateral branch, left branch, and right medial branch. Although hepatic arterial variation appears to be common in dogs, only one dog in this study had the caudate lobar branch as the first branch of the hepatic artery. Further study on a larger number of dogs with CT images will be needed to identify and classify the pattern of hepatic arterial variations.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.3
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• pp.233-248
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• 2012

The national emission from energy sector accounted for 84.7% of all domestic emissions in 2007. Of the energy-use emissions, the emission from mobile source as one of key categories accounted for 19.4% and further the road transport emission occupied the most dominant portion in the category. The road transport emissions can be estimated on the basis of either the fuel consumed (Tier 1) or the distance travelled by the vehicle types and road types (higher Tiers). The latter approach must be suitable for simultaneously estimating $CO_2$, $CH_4$, and $N_2O$ emissions in local administrative districts. The objective of this study was to estimate 31 municipal GHG emissions from road transportation in Gyeonggi Province, Korea. In 2008, the municipalities were consisted of 2,014 towns expressed as Dong and Ri, the smallest administrative district unit. Since mobile sources are moving across other city and province borders, the emission estimated by fuel sold is in fact impossible to ensure consistency between neighbouring cities and provinces. On the other hand, the emission estimated by distance travelled is also impossible to acquire key activity data such as traffic volume, vehicle type and model, and road type in small towns. To solve the problem, we applied a hierarchical cluster analysis to separate town-by-town road patterns (clusters) based on a priori activity information including traffic volume, population, area, and branch road length obtained from small 151 towns. After identifying 10 road patterns, a rule building expert system was developed by visual basic application (VBA) to assort various unknown road patterns into one of 10 known patterns. The expert system was self-verified with original reference information and then objects in each homogeneous pattern were used to regress traffic volume based on the variables of population, area, and branch road length. The program was then applied to assign all the unknown towns into a known pattern and to automatically estimate traffic volumes by regression equations for each town. Further VKT (vehicle kilometer travelled) for each vehicle type in each town was calculated to be mapped by GIS (geological information system) and road transport emission on the corresponding road section was estimated by multiplying emission factors for each vehicle type. Finally all emissions from local branch roads in Gyeonggi Province could be estimated by summing up emissions from 1,902 towns where road information was registered. As a result of the study, the GHG average emission rate by the branch road transport was 6,101 kilotons of $CO_2$ equivalent per year (kt-$CO_2$ Eq/yr) and the total emissions from both main and branch roads was 24,152 kt-$CO_2$ Eq/yr in Gyeonggi Province. The ratio of branch roads emission to the total was 0.28 in 2008.

• Advances in concrete construction
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• v.9 no.1
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• pp.103-113
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• 2020

This paper deal with the critical fluid velocity response of nanocomposite pipe conveying fluid based on numerical method. The pressure of fluid is obtained based on perturbation method. The motion equations are derived based on classical shell theory, energy method and Hamilton's principle. The shell is reinforced by nanoparticles and the distribution of them are functionally graded (FG). The mixture rule is applied for obtaining the equivalent material properties of the structure. Differential quadrature method (DQM) is utilized for solution of the motion equations in order to obtain the critical fluid velocity. The effects of different parameters such asCNT nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios and internal fluid are presented on the critical fluid velocity response structure. The results show that with increasing the CNT nanoparticles, the critical fluid velocity is increased. In addition, FGX distribution of nanoparticles is the best choice for reinforcement.

• Computers and Concrete
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• v.18 no.5
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• pp.1053-1063
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• 2016

As concrete is most usable material in construction industry it's been required to improve its quality. Nowadays, nanotechnology offers the possibility of great advances in construction. For the first time, the nonlinear buckling of straight concrete columns armed with single-walled carbon nanotubes (SWCNTs) resting on foundation is investigated in the present study. The column is modelled with Euler-Bernoulli beam theory. The characteristics of the equivalent composite being determined using the Mori-Tanaka model. The foundation around the column is simulated with spring and shear layer. Employing nonlinear strains-displacements, energy methods and Hamilton's principal, the governing equations are derived. Differential quadrature method (DQM) is used in order to obtain the buckling load of structure. The influences of volume percent of SWCNTs, geometrical parameters, elastic foundation and boundary conditions on the buckling of column are investigated. Numerical results indicate that reinforcing the concrete column with SWCNTs, the structure becomes stiffer and the buckling load increases with respect to concrete column armed with steel.

• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.483-487
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• 2015

The different calculated quantum chemical descriptors by DFT method were used for prediction of some sulphanilamide Schiff bases inhibitor activity as a binding constant (log K). Multiple linear regression (MLR) and artificial neural network (ANN) were employed for developing the useful quantitative structure activity relationship (QSAR) model. The obtained results presented superiority of ANN model over the MLR one. The offering QSAR model is very easy to computation and Physico-Chemically interpretable. Sensitivity analysis was used to determine the relative importance of each descriptor in ANN model. The order of importance of each descriptor according to this analysis is: molecular volume, molecular weight and dipole moment, respectively. These descriptors appear good information related to different structure of sulphanilamide Schiff bases can participate in their inhibitor activity.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.124-129
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• 2013

Electro-Mechanical Batteries have important advantages compared with chemical batteries, especially in Low Earth Orbit satellites applications. High speed, slotless, external rotor, brushless DC machines are proposed and used in these systems as Motor/Generator. A simplified analytic design method is given for this type of machines and, the optimization of machine in order to have maximum efficiency and minimum volume and weight are given in this paper. Particle swarm optimization (PSO) is used as the optimization algorithm and the finite element-based simulations are used to confirm the design and optimization process and show less than 6% error in parametric design.

• Wind and Structures
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• v.24 no.1
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• pp.43-57
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• 2017

The use of nanotechnology materials and applications in the construction industry should be considered for enhancing material properties. However, the nonlinear buckling of an embedded straight concrete columns reinforced with silicon dioxide ($SiO_2$) nanoparticles is investigated in the present study. The column is simulated mathematically with Euler-Bernoulli and Timoshenko beam models. Agglomeration effects and the characteristics of the equivalent composite are determined using Mori-Tanaka approach. The foundation around the column is simulated with spring and shear layer. The governing equations are derived using energy method and Hamilton's principal. Differential quadrature method (DQM) is used in order to obtain the buckling load of structure. The influences of volume percent of $SiO_2$ nanoparticles, geometrical parameters and agglomeration on the buckling of column are investigated. Numerical results indicate that considering agglomeration effects leads to decrease in buckling load of structure.

• Wind and Structures
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• v.30 no.2
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• pp.133-140
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• 2020

In this paper, critical fluid velocity and frequency of laminated pipe conveying fluid are presented. Each layer of the pipe is reinforced by functionally graded carbon nanotubes (FG-CNTs). The internal fluid is assumed turbulent and the induced forces are calculated by momentum equations. The pipe is resting on viscoelastic foundation with spring, shear and damping constants. The motion equations are derived based on classical shell theory and energy method. Differential quadrature method (DQM) is used for solution and obtaining the critical fluid velocity. The effects of volume percent and distribution of CNT, boundary condition, lamina layer number, length to radius ration of pipe, viscoelastic medium and fluid velocity are shown on the critical fluid velocity. Results show that with increasing the lamina layer number, the critical fluid velocity increases.