• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1468-1472
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• 2007

The present study was carried out to determine the optimum conditions of different factors (ratio of lard to water, ${\beta}$-CD concentrations, mixing temperature, mixing time and mixing speed) on cholesterol reduction from lard by using crosslinked ${\beta}$-CD. Crosslinked ${\beta}$-CD was prepared with adipic acid. When the lard was treated under different conditions, the range of cholesterol removal was 91.2 to 93.0% with 5% crosslinked ${\beta}$-CD, which was not significantly different among treatments. In a recycling study, cholesterol removal with crosslinked ${\beta}$-CD in the first trial was 92.1%, which was similar to that with new crosslinked ${\beta}$-CD. In up to eight time trials, over 90% of cholesterol removal was found. The present study indicated that the optimum conditions for cholesterol removal using crosslinked ${\beta}$-CD were a 1:3 ratio of lard to water, 5% crosslinked ${\beta}$-CD concentration, $40^{\circ}C$ mixing temperature, 1 h mixing time and 150 rpm mixing speed. In addition, crosslinked ${\beta}$-CD made by adipic acid resulted in an effective recycling efficiency.

• Smart Structures and Systems
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• v.13 no.1
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• pp.1-24
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• 2014

The present study deals with two dimensional electro-elastic analysis of a functionally graded piezoelectric (FGP) cylinder under internal pressure. Energy method and first order shear deformation theory (FSDT) are employed for this purpose. All mechanical and electrical properties except Poisson ratio are considered as a power function along the radial direction. The cylinder is subjected to uniform internal pressure. By supposing two dimensional displacement and electric potential fields along the radial and axial direction, the governing differential equations can be derived in terms of unknown electrical and mechanical functions. Homogeneous solution can be obtained by imposing the appropriate mechanical and electrical boundary conditions. This proposed solution has capability to solve the cylinder structure with arbitrary boundary conditions. The previous solutions have been proposed for the problem with simple boundary conditions (simply supported cylinder) by using the routine functions such as trigonometric functions. The axial distribution of the axial displacement, radial displacement and electric potential of the cylinder can be presented as the important results of this paper for various non homogeneous indexes. This paper evaluates the effect of a local support on the distribution of mechanical and electrical components. This investigation indicates that a support has important influence on the distribution of mechanical and electrical components rather than a cylinder with ignoring the effect of the supports. Obtained results using present method at regions that are adequate far from two ends of the cylinder can be compared with previous results (plane elasticity and one dimensional first order shear deformation theories).

• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.15-34
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• 2012

In the present paper, an improved high-order theory is used for bending analysis of soft-core sandwich plates. Third-order plate assumptions are used for face sheets and quadratic and cubic functions are assumed for transverse and in-plane displacements of the orthotropic soft core. Continuity conditions for transverse shear stresses at the interfaces as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of the plate are satisfied. Also, transverse flexibility and transverse normal strain and stress of the orthotropic core are considered. The equations of motion and boundary conditions are derived by principle of minimum potential energy. Analytical solution for bending analysis of simply supported sandwich plates under various transverse loads are presented using Navier's solution. Comparison of the present results with those of the three-dimensional theory of elasticity and some plate theories in the literature confirms the accuracy of the proposed theory.

• Steel and Composite Structures
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• v.49 no.6
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• pp.603-614
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• 2023

In this paper, frequency analysis of curved functionally graded (FG) nanobeam by consideration of deepness effect has been studied. Differential transform method (DTM) has been used to obtain frequency responses. The nonlocal theory of Eringen has been applied to consider nanoscales. Material properties are supposed to vary in radial direction according to power-law distribution. Differential equations and related boundary conditions have been derived using Hamilton's principle. Finally, by consideration of nonlocal theory, the governing equations have been derived. Natural frequencies have been obtained using semi analytical method (DTM) for different boundary conditions. In order to study the effect of deepness, the deepness term is considered in strain field. The effects of the gradient index, radius of curvature, the aspect ratio, the nonlocal parameter and interaction of aforementioned parameters on frequency value for different boundary conditions such as clamped-clamped (C-C), clamped-hinged (C-H), and clamped-free (C-F) have been investigated. In addition, the obtained results are compared with the results in previous literature in order to validate present study, a good agreement was observed in the present results.

• Steel and Composite Structures
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• v.28 no.6
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• pp.655-670
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• 2018

A coupled method, that combines the Ritz method and the finite element (FE) method, is proposed to solve the vibration problem of rectangular thin and thick plates with general boundary conditions. The eigenvalue partial differential equation(s) of the plate is (are) first reduced to a set of eigenvalue ordinary differential equations by the application of the Ritz method. The resulting eigenvalue differential equations are then reduced to an eigenvalue algebraic equation system using the finite element method. The natural boundary conditions of the plate problem including the free edge and free corner boundary conditions are also implemented in a simple and accurate manner. Various boundary conditions including simply supported, clamped and free boundary conditions are considered. Comparisons with existing numerical and analytical solutions show that the proposed mixed method can produce highly accurate results for the problems considered using a small number of Ritz terms and finite elements. The proposed mixed Ritz-FE formulation is also compared with the mixed FE-Ritz formulation which has been recently proposed by the present author and his co-author. It is found that the proposed mixed Ritz-FE formulation is more efficient than the mixed FE-Ritz formulation for free vibration analysis of rectangular plates with Levy-type boundary conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.91.1-91.1
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• 2010

The Reforming system is an effective method to generate hydrogen which uses for fuel cell system. The purpose of this study is to present characteristics of an autothermal reformer at various operating conditions and to investigate ideal conditions for reforming efficiency. Dominant chemical reactions are Full Combustion, Steam Reforming reaction, Water-Gas Shift reaction and Direct Steam Reforming reaction. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio, Steam to Carbon Ratio and Gas Hourly Space Velocity. Autothermal reformer is filled with catalysis of a packbed-bed type. Using numerical approach, we have investigated on various reaction conditions.

• Steel and Composite Structures
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• v.24 no.2
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• pp.141-149
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• 2017

In this study, vibration analysis of fluid conveying microbeams under non-ideal boundary conditions (BCs) is performed. The objective of the present paper is to describe the effects of non-ideal BCs on linear vibrations of fluid conveying microbeams. Non-ideal BCs are modeled as a linear combination of ideal clamped and ideal simply supported boundary conditions by using the weighting factor (k). Non-ideal clamped and non-ideal simply supported beams are both considered to show the effects of BCs. Equations of motion of the beam under the effect of moving fluid are obtained by using Hamilton principle. Method of multiple scales which is one of the perturbation techniques is applied to the governing linear equation of motion. Approximate solutions of the linear equation are obtained and the effects of system parameters and non-ideal BCs on natural frequencies are presented. Results indicate that, natural frequencies of fluid conveying microbeam changed significantly by varying the weighting factor k. This change is more remarkable for clamped microbeams rather than simply supported ones.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.670-676
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• 2007

A comparative study on ground boundary conditions for the airfoil in ground effect has been carried out. The objective of the present study is to clarify effects of the ground boundary conditions so that it will be helpful to analyse results of wind tunnel tests using the fixed ground board or the image method. A low Mach number preconditioned Navier-Stokes solver using the overlap grid method has been applied. It has been turned out that results with the symmetric boundary condition are almost the same to those with the moving boundary condition. Results with the fixed ground boundary show discrepancy to those with the moving boundary condition when flow separation on the ground board takes place.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.241-244
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• 2006

The present paper describes the scale effect correction method for wind turbine by using CFD(computational fluid dynamics). For the correct ions of wind turbine scale effect, various researches on the helicopter rotor scale effect were Investigated and feasibility study of methods was performed to correct wind turbine scale effect The present paper also introduces new scale effect correction method based on two dimensional lift slope modification. In order to test the Present method, performance analyses of NREL Phase VI wind turbines under various scale conditions were carried out by using CFD. The present method showed reasonable results when applied to NREL Phase VI wind turbine.

• Steel and Composite Structures
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• v.38 no.1
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• pp.1-15
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• 2021

In this paper, a higher order shear deformation theory for bending analysis of functionally graded plates resting on Pasternak foundation and under various boundary conditions is exposed. The proposed theory is based on the assumption that porosities can be produced within functionally graded plate which may lead to decline in strength of materials. In this research a novel distribution of porosity according to the thickness of FG plate are supposing. Governing equations of the present theory are derived by employing the virtual work principle, and the closed-form solutions of functionally graded plates have been obtained using Navier solution. Numerical results for deflections and stresses of several types of boundary conditions are presented. The exactitude of the present study is confirmed by comparing the obtained results with those available in the literature. The effects of porosity parameter, slenderness ratio, foundation parameters, power law index and boundary condition types on the deflections and stresses are presented.