bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Modified Non-Dominated Sorting Genetic Algorithm with Fractional Factorial Design for Multi-Objective Optimization Problems
Authors: Liu J.-L. , Lee T.-F. 
Published: May 2011

AbstractThis study develops an intelligent non-dominated sorting genetic algorithm (GA), called INSGA herein, which includes a non-dominated sorting, crowded distance sorting, binary tournament selection, intelligent crossover and non-uniform mutation operators, for solving multi-objective optimization problems (MOOPs). This work adopts Goldberg's notion of non-dominated sorting and Deb's crowded distance sorting in the proposed MOGA to achieve solutions with good diversity-preservation and uniform spread on the approximated Pareto front. In addition, the chromosomes of offspring are generated based on an intelligent crossover operator using a fractional factorial design to select good genes from parents intelligently and achieve the goals of fast convergence and high numerical accuracy. To further improve the fine turning capabilities of the presented MOGA, a non-uniform mutation operator is also applied. A typical mutation approach is to create a random number and then add it to corresponding original value. Performance evaluation of the INSGA is examined by applying it to a variety of unconstrained and constrained multi-objective optimization functions. Moreover, two engineering design problems, which include a two-bar truss design and a welded beam design, are studied by the proposed INSGA. Results include the estimated Pareto-optimal front of non-dominated solutions.
Computational Modeling of Microchannel Flows on Laboratory Compact Disk (LABCD)
Authors: Lin C.-M. , Lin T.-C. , Tan C.-M. , Tsai T.-H. 
Published: May 2011

AbstractThis paper models and analyzes flows in linear and curved microchannels on a rotating Laboratory Compact Disk (LabCD). The effects of centrifugal force are introduced into the governing equations of the microchannel flow to promote the fluidic velocity in the microchannel. The microchannel types on the LabCD must be designed following a process of mathematical identification. A flow model which takes into account the combined effects of viscosity, capillary forces, pressure difference and rotation is developed. A reduction-order technique is applied to obtain linear and nonlinear governing equations for flows in straight and curviform microchannels, respectively. The analytical solutions for the flow in the tubular microchannel are obtained using the Laplace transform method, while the numerical solutions for the curviform microchannel or microchannel with a varying cross-section are obtained using a piecewise linear method. The results show that the analyzed models are easily presented by a mathematical expression for the case of a tubular microchannel and simulated using a numerical program for the case of special microchannels. The modeling presented in this paper enables the performance of LabCD devices to be significantly enhanced by providing insights into the fluid flow behavior in microchannels of varying configurations under different rotational velocities.
The Dynamics of Balance Control During Slipping
Authors: Chou You-Li , You Jia-Yuan , Lin Chii-Jeng , Su Fong-Chin , Chou Pei-Hsi 
Published: May 2011

ABSTRACTThis study investigates experimentally the velocity of the center of mass with respect to the base of support while subjects step on slippery flooring. The moments of the joints of both legs are also investigated to gain further insights into the source of any correlation found in reacting to slippery perturbation. Twenty-two healthy subjects dressed with safety harness walked first without and then with slippery perturbation, guided by a metronome at 120 steps/min and 90 steps/min cadence. Data were collected from a motion analysis system and force plates. Subjects falling had distinguishably slower velocity of center of mass with respect to the lead stance foot compared to the subjects maintaining balance at contralateral toe off. Larger knee flexion moment and ankle plantar flexion moment in the perturbed leg were found among subjects regaining balance. Faster velocity of center of mass with respect to base of support is noteworthy in subjects regaining balance from slippery perturbation. The response of lower extremities, especially about the thigh and leg in the lead stance limb, were important to improve the velocity of the center of mass with respect to base of support.
A Novel Method for Determining Poisson's Ratio of Thin Film Materials Using Ultra-Wide Micromachined Bilayer Cantilevers
Authors: Hou Max Ti-Kuang , Chen Rongshun 
Published: May 2011

AbstractNarrow micromachined bilayer cantilevers, which are broadly used to determine different thin film material properties, have rarely been used to characterize the Poisson's ratio. It is difficult to be determined from the tip deflection, and thus the Poisson's ratio, of the narrow bilayer cantilever. In this paper, the tip deflections of ultra-wide micromachined bilayer cantilevers carry the needed information for finding the Poisson's ratio of thin-film materials. The measurement process and its corresponding model, based on the plate theory, is introduced and tested. The Poisson's ratio of the thin film is determined by comparing the tip deflections of the bilayer cantilever before and after the deposition of the upper layer. Because the fabrication processes are widely used in surface micromachining, the method can be easily implemented.
Collinear Crack Problem in Antiplane Elasticity for a Strip of Functionally Graded Materials
Authors: Chen Y. Z. 
Published: May 2011

AbstractIn this paper, elastic analysis for a collinear crack problem in antiplane elasticity of functionally graded materials (FGMs) is present. An elementary solution is obtained, which represents the traction applied at a point “x” on the real axis caused by a point dislocation placed at a point “t” on the same real axis. The Fourier transform method is used to derive the elementary solution. After using the obtained elementary solution, the singular integral equation is formulated for the collinear crack problem. Furthermore, from the solution of the singular integral equation the stress intensity factor at the crack tip can be evaluated immediately. In the solution of stress intensity factor, influence caused by the materials property “α” is addressed. Finally, numerical solutions are presented.
Velocity Distribution of Non-Darcy Flow in a Porous Medium
Authors: Leu J. M. , Chan H. C. , Tu Lih-Fu , Jia Yafei , Wang S. Y. 
Published: May 2011

AbstractThis study theoretically and experimentally investigates the velocity distributions of the interface boundary layer region in a porous medium. By combining a quadratic non-Darcy law and a practical eddy viscosity model, an analytical solution is derived and presented. Three additional parameters, i.e., the depth of the interface boundary layer region, the slip velocity, and proportionality constant, are contained in the analytical solution. The measured experimental data show the depth of the interface boundary layer region only depends on the characteristics of the porous medium rather than the relative flow depth, bed slop, or Reynolds number. The values of the slip velocity are found to increase with increasing relative mean clear fluid velocities. The proportionality constant plays an important role in modeling the penetration of turbulence and the associated momentum transfer. The measured experimental velocity distribution is used to evaluate the accuracy of the analytical predicted profile. The analytical results obtained in this study are in agreement with the measured experimental results.
An Analytical Approach for the Green's Functions of Biharmonic Problems with Circular and Annular Domains
Authors: Chen J. T. , Liao H. Z. , Lee W. M. 
Published: May 2011

AbstractIn this paper, an analytical approach for deriving the Green's function of circular and annular plate was presented. Null-field integral equations were employed to solve the plate problems while kernel functions were expanded to degenerate kernels. The unknown boundary data of the displacement, slope, normal moment and effective shear force were expressed in terms of Fourier series. It was noticed that all the improper integrals were avoided when the degenerate kernels were used. After determining the unknown Fourier coefficients, the displacement, slope, normal moment and effective shear force of the plate could be obtained by using the boundary integral equations. The present approach was seen as an “analytical” approach for a series solution. Finally, several analytical solutions were obtained. To see the validity of the present method, FEM solutions using ABAQUS were compared well with our analytical solutions. The displacement, radial moment and shear variations of radial and angular positions were presented.
The Magnetoelastic Problem for a Soft Ferromatnetic Elastic Half-Plane with a Crack and a Constant Magneic Induction
Authors: Yeh C.-S. , Ren C.-W. 
Published: May 2011

AbstractThe stress state of a magnetized elastic half-plane with a uniformly pressurized crack parallel to the free surface subjected to a uniform magnetic induction Bo is considered. The linear theory for a soft ferromagnetic elastic solid with muti-domain structure, which has been developed by Pao and Yeh [1] is adopted to investigate this problem. A numerical method is developed to determine the magnetoelastic stress intensity factor. The effect of the magnetic field and the boundary conditions on the magnetoelasitc stress intensity factor are shown graphically and numerically.
General Interface Conditions in Surface Elasticity of Nanoscaled Solids in General Curvilinear Coordinates
Authors: Weng C.-N. , Chen T. Y. 
Published: May 2011

AbstractWe consider an arbitrarily curved three-dimensional thin interphase with surface stresses between two anisotropic solids. Letting the interphase be infinitely thin and assuming that the kinematic constraints between the two anisotropic solids remain intact during the deformation, we derive the interface jump conditions along the interface. These conditions are derived analytically in general non-orthogonal curvilinear coordinates in the setting of linear elasticity and steady state conduction. The proof is made directly from a force balance consideration of a small element of the curved interface. Simplified results are also deduced for oblique coordinate systems in which the coordinate axes are straight lines that are not perpendicular to each other. When the axes are orthonormal, we prove that our results agree with the previous known Young-Laplace conditions in solids.
Dynamic Interactions of a High-Speed Vehicle and a Distributed Discretely Supported Guideway
Authors: Hu C.-Y. , Chen K.-C. , Chen J.-S. 
Published: May 2011

AbstractThis study investigates the dynamic interactions between a vehicle and guideway of a high-speed ground transportation system based on maglev vehicles. The guideway is assumed to be made up of identical simply supported beams with single spans and rigid supports. The vehicle is considered to a two-dimensional vehicle model with primary and secondary suspensions. Three kinds of loading modes acting at each beam of guideway are first developed according to the locations of suspensions of vehicle. Coupled equations of motion of both vehicle and guideway in various loading modes are derived and solved by using numerical integration method. The simulations have been performed to investigate the parameters of vehicle/guideway system which may affect the steady-state responses of the vehicle and guideway.
Optimal Design and Operation on Convergent-Divergent Nozzle Type No-Moving-Part Valves (NMPV) in Microchannel
Authors: Leu T.-S. , Wang C.-T. , Sun J.-M. 
Published: May 2011

AbstractThe no-moving-part valve (NMPV) pump design has been proven to be a better micro pump design for its easier fabrication, cost-effective and no destroying flow particle. Previous literatures often used a diffuser design with a divergent angle for NMPV studies. Different from previous studies, we apply a convergent-divergent (C-D) nozzle with convergent half angle θ1 and divergent half angle θ2 for NMPV design in this study. By using the dipole value (Dip) of current C-D nozzle type NMPV as an objective function in “Design of Experiments” (DOE) and “Response Surface Modeling” (RSM) optimization methods, C-D nozzle type NMPV with convergent half angles near θ1 = 46° ∼ 54° and divergent half angles θ2 = 113° ∼ 116° has a maximum peak region for Dip value. It is found that the optimal design with the convergent half angle of θ1 = 60° and the divergent half angle of θ2 = 110°. The operational Reynolds numbers raging from 20 to 30 are suggested for the optimal design and operation condition for the current C-D nozzle type NMPV. It is also verified that the C-D nozzle type NMPV pump design has a better performance than the typical diffuser type NMPV pump design. These findings would be useful to the design and operation for C-D nozzle type NMPV micropump.
Unsteady Analysis of the Flow Rectification Performance of Conical Microdiffuser Valves for Valveless Micropump Applications
Authors: Wang Y.-C. , Lin S.-H. , Jang D. 
Published: May 2011

AbstractA numerical analysis of the unsteady flows in conical microdiffusers appropriate for valveless micropump applications is performed. The rectification efficiency of the diffuser valve is calculated directly as a function of geometric and operational parameters, including diffuser angle, diffuser slenderness, sizes of actuation chamber and inlet/outlet port, actuation frequency, and amplitude of actuation pressure. The computational results show that the diffuser with diverging angle of 10° and slenderness of 7.5 has the best rectification performance. For large actuation pressure amplitude, the optimal rectification efficiency and its corresponding Roshko number are relatively high. At the optimal Roshko number, the flow impedance is found to be dominated by fluid inertia. Sizes of the pump chamber and inlet/outlet port are shown to have a prominent effect on valve performance. Small actuation chamber or small inlet/outlet port can significantly deteriorate the valving performance of the diffuser.
Atomistic Analysis of Nano-Scale Crystal Plasticity in Thin Metal Films
Authors: Shen Y.-L. , Leger R. W. 
Published: May 2011

ABSTRACTNumerical simulations based on molecular statics are carried out to study nano-scale plastic deformation behavior in thin metal films. Particular attention is devoted to correlating the overall mechanical response and the underlying crystal defect mechanisms during mechanical loading. The simulations are within the two-dimensional framework involving pair molecular interactions in singlecrystal materials. Special modeling features are utilized for studying the formation of dislocations, interface characteristics, and defect interactions. Specific problems investigated in this work include: plastic deformation and tensile fracture in a free-standing film, interface-constrained plasticity in substrate-bonded films, and homogeneous nucleation of dislocations during nanoindentation.
Heat and Mass Transfer in an Inclined Semi-Annular Enclosure
Authors: Wang L.W. , Kung Y.C. , Lai S.D. 
Published: May 2011

AbstractAn experimental investigation of heat transfer carried out for a semiannular enclosure. Inner and outer walls of the enclosure were kept at different but constant temperatures. The semiannular enclosure was filled with a CuSO4 - H2SO4 - H2O solution. An electrochemical method has been used for the mass transfer. The purpose of this study is to investigate flows resulting from buoyancy due to a combination of both temperature and concentration gradients in the enclosure. The flow structure in the enclosure was visualized by the shadowgraph technique. Flow visualization photograph showed interesting multi-cell flow structures in the enclosure for the cooperating and opposing thermal and solutal buoyancy. An optical technique is based on the idea that the intensity of the light beam absorbed by the copper sulphate solution is proportional to the solution concentration when the light beam passes through the solution. For each flow regime the mass transfer coefficient across the enclosure was also measured. The ranges of the dimensionless parameters studied in the experimental were Ar = 0.23, k = 2.5, Sc = 1700∼2300, Pr = 6.5 ∼ 7.3, Grt = 104 ∼ 106, N = −15.44 ∼ 6.16, θ = 45°∼90°.
On Invariants of Anisotropic Elasticity Constants
Authors: Wang Min-Zhong , Zhao Bao-Sheng 
Published: May 2011

ABSTRACTWith the aid of a six-dimensional special eigenvectorq, T.C.T.Ting finds five new invariants of anisotropic elasticity constants. The purpose of this paper is to consider some character of the eigenvectorq. It is pointed that the six-dimensional special eigenvectorqis unique, if it is independent of the coordinate transformation, and the general form of a three-rank orthogonal matrix is given if it has a three-dimensional special eigenvector likeq. In addition, the concept of the special eigenvectorqis extended and 20 invariants of anisotropic elasticity constants are obtained under rotation about x3-axis.
On the Energy Release Rate of Elliptical Cracks in Anisotropic Elastic Media
Authors: Xue Yibin , Qu Jianmin 
Published: May 2011

ABSTRACTThis brief note discusses some issues related to the calculation of energy release rate for elliptical cracks in anisotropic solids. By using the Stroh formalism, analytical expressions of the energy release rate are obtained for elliptical cracks in an unbounded anisotropic solid. Because of material anisotropy and geometric asymmetry of the crack, the local energy release rate varies along the crack front. The average energy release rate can be obtained by integrating the local energy release rate over the entire crack front. On the other hand, the total work done by the crack-surface traction on the entire crack opening displacement can be easily evaluated once the crack opening displacement is known. It is shown that the average energy release rate is equal to the rate of change per unit crack area increment of the work done by the external load on the crack opening displacement.
Green's Function for the Damped Wave Equation on a Finite Interval Subject to Two Robin Boundary Conditions
Authors: Yen David H. Y. 
Published: May 2011

ABSTRACTThe Green's function for the damped wave equation on a finite interval subject to two Robin boundary conditions is studied. The problem for a semi-infinite interval with one Robin boundary is considered first by the Laplace transform method to establish the reflection principle at a Robin boundary. It is seen that the reflected wave generated by an exiting wave at a Robin boundary is a convolution involving the exiting wave and some kernel function. This generalizes the well known classical results for reflections at Dirichlet and Neumann boundaries. The reflection principle at a Robin boundary is then used for the finite interval case by considering multiple reflections and this leads to an infinite sequence of waves. In order to justify the results obtained here we also study the finite interval case by the Laplace transform method. The Laplace transform of the Green's function is expanded, for large values of the transform parameter, into an infinite series of negative exponentials and then inverted term by term. Agreement is reached between these two approaches.
Design and Simulation of Continuous Dielectrophoretic Flow Sorters
Authors: Leu T.-S. , Chen H.-Y. , Hsiao F-B. 
Published: May 2011

AbstractThis paper was an attempt to investigate, through numerical simulation, the designs of DEP flow sorters when applied with different ratios of the electrodes to generate different electrical fields, and to explore the sorting capability of the flow sorters, defined as the degree of particle deflection, under different operation of parameters.In order to obtain the maximal DEP negative particle deflection, which was believed as an indicator of greater sorting capability, we have investigated different non-uniform electrical fields produced by combinations of electrodes with different length of two poles, ranging from 1:2 up to 1:9. The finding of numerical simulation indicated that the length ratio 1:3 of the electrode poles produced the electrical fields that maximized the particle deflection.Moreover, different parameters of applied voltage, flow rate, particle diameters, and distance between two electrical poles were designed to investigate their effects on particle deflection of flow sorters. The numerical simulation of the study showed that the DEP flow sorter was demonstrated as a linear system with respect to the applied voltage and particle diameter. In this study, we tried to operationally define flow rate as the time duration while the flow passed the electrical fields, and thus investigated how particle deflect with the different time given. We found that the particle deflected more when the flow was allowed with longer time to pass the electrical fields. The study also showed that the distance the particles deflect from the centerline is in inverse proportion to the square distance between the two electrical poles.
Dependence of the Smagorinsky-Lilly's Constant on Inertia, Wind Stress, and Bed Roughness for Large Eddy Simulations
Authors: Chung W.-H. 
Published: May 2011

AbstractEquations governing large eddy simulations are usually closed by incorporating with the Smagorinsky-Lilly's turbulence model of eddy viscosity. The model contains a so-called filtering length and a Smagorinsky-Lilly “constant” that changes among different researchers. The variation range of the constant is wide and its value is usually determined in a sense of “guessing”. Since the constant is closely related to the magnitude of eddy viscosity, hence to our numerical solutions eventually, setting a more precise and determinate procedure for prescribing the constant seems to be worthy it. The constant,CSL, is first estimated in use of the properties of fluid flow within the inertia subrange. Then, along with a general derivation, the explicit closed-form expression for the constant is presented for steady uniform flows. It is found that, with the analogy between the filtering technique and Reynolds average,CSLmay not necessarily be constant but proportional to the Manning n and water depth. Other than the determination ofCSL, the vertical flow velocity profile in an infinitely long wide rectangular channel without spiral flow motion is obtained through the use of the Smagorinsky-Lilly's turbulence closure model. It is shown analytically that the velocity profile in unsteady open channel flow can be expressed as a function of an integration functionJn(z)that accounts for wind stress and inertia terms. With the velocity profile, effects of inertia terms, wind stress, and channel bed roughness onCSLare deeply explored in response to the dependence ofCSLonJn(z).