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In this paper we consider two least-squares methods: the discontinuous Petrov-Galerkin method and a new version of the hybridized discontinuous Petrov-Galerkin method. The aim of this paper is to compute the optimal test functions for these methods in the Babuska-Ihlenburg problem in 1D. The optimal test functions will be computed with respect to the chosen inner product spaces and bilinear forms. We shall show numerical results of h-convergence of the methods. [ABSTRACT FROM AUTHOR]

Flange vertical buckling is one of the collapse types of an I-shaped steel girder under bending, and has been considered to occur only in girders with very slender web plate. However, in authors' experimental test on the hybrid steel girders, the flange vertical buckling was observed in one of the test models. In this paper, a numerical analysis is made on flange vertical buckling in a hybrid steel girder. The aim of this paper is, as a first step on the research on flange vertical buckling of hybrid steel girders, reproducing and realizing the flange vertical buckling with the numerical analysis, and to study the basic behaviour of flange vertical buckling of the hybrid steel girders. [ABSTRACT FROM AUTHOR]

A single dielectric barrier discharge is a specific configuration for plasma actuators consisting of two electrodes, one coated by a dielectric material and the other is exposed to the air. The purpose of this paper is to study the characteristics of single dielectric barrier discharge (DBD) plasma actuator through numerical modeling. A mathematical model that represents the physical system is presented and the numerical simulations for specific geometry are discussed in this paper. With this model, we can study the physics of the plasma flow. The formulation of the governing equations are divided into two since the physical system can be distinctly separated; one is the electrostatic part and the other is on the fluid flow. The electrostatic part is formulated using the Maxwell's equation which needs to be modified to incorporate the current frequency equation so that the system of equations becomes unsteady which is more realistic compared to a steady system of equations. The fluid flow part is formulated using the Navier-Stokes equations. The equations are re-represented using a vorticity term and stream function so that the flow characteristics can be clearly visualized. All equations are discretized using finite difference method. The discretized equations are then solved using the Gauss-Seidel iteration method. The numerical results show that the vorticity of the plasma is similar in pattern at each time interval. The highest magnitude of the vorticity occurs at the inner part near end of the upper electrode but this magnitude is different at each time. On varying the applied voltage, it is found that the peak vorticity also increases. Therefore, this shows that both the applied voltage and the geometry of the system influence the characteristics of the plasma flow. [ABSTRACT FROM AUTHOR]

It has been reported that Internet Protocol (IP) packet traffic exhibits self-similarity or long range dependence (LRD) and causes the degradation of switch performance. Therefore, it is crucial for an appropriate buffer design of a switch. In this paper, we investigate delay behavior of the switch under self-similar variable length packet traffic by modeling it as MMPP/M/1/K queueing system wherein MMPP (Markov-Modulated Poisson Process) is fitted by equating the variance of MMPP and that of self-similar traffic. MMPP model is already validated one to emulate the self-similar characteristics. Voids that will occur because of variability in packet length is considered. We investigate mean delay against system parameters, traffic parameters and fitting parameters. Numerical results show that analysis presented in this paper is useful in dimensioning the switch. [ABSTRACT FROM AUTHOR]

Text mining, sometimes alternately referred to as text analytics, refers to the process of extracting high-quality knowledge from the analysis of textual data. Text mining has wide variety of applications in areas such as biomedical science, news analysis, and homeland security. In this paper, we describe an approach and some relatively small-scale experiments which apply text mining to neuroscience research literature to find novel associations among a diverse set of entities. Neuroscience is a discipline which encompasses an exceptionally wide range of experimental approaches and rapidly growing interest. This combination results in an overwhelmingly large and often diffuse literature which makes a comprehensive synthesis difficult. Understanding the relations or associations among the entities appearing in the literature not only improves the researchers current understanding of recent advances in their field, but also provides an important computational tool to formulate novel hypotheses and thereby assist in scientific discoveries. We describe a methodology to automatically mine the literature and form novel associations through direct analysis of published texts. The method first retrieves a set of documents from databases such as PubMed using a set of relevant domain terms. In the current study these terms yielded a set of documents ranging from 160,909 to 367,214 documents. Each document is then represented in a numerical vector form from which an Association Graph is computed which represents relationships between all pairs of domain terms, based on co-occurrence. Association graphs can then be subjected to various graph theoretic algorithms such as transitive closure and cycle (circuit) detection to derive additional information, and can also be visually presented to a human researcher for understanding. In this paper, we present three relatively small-scale problem-specific case studies to demonstrate that such an approach is very successful in replicating a neuroscience expert's mental model of object-object associations entirely by means of text mining. These preliminary results provide the confidence that this type of text mining based research approach provides an extremely powerful tool to better understand the literature and drive novel discovery for the neuroscience community. [ABSTRACT FROM AUTHOR]

Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction. Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge® software, is based on data taken from Outeiro & al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature. Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R&D to those given by numerical simulations is achieved. [ABSTRACT FROM AUTHOR]

This paper deals with the simulation of UNS A92024 aluminium alloy cutting processes. In particular, 2D and 3D Finite Element Method (FEM) simulations were carried out in order to estimate cutting forces and chip morphology during turning operations. The material is modelled with two different set of parameters for the Johnson-Cook's (J-C) constitutive equation and a failure Cockroft and Latham's model exploited considers damage. The comparison between the predicted chip morphology and principal cutting forces at varying of J-C parameters and cutting regimes with those experimentally found are presented and discussed. The paper shows the importance of damage criterion in the cutting forces, during the simulation, especially in 3D. [ABSTRACT FROM AUTHOR]

A new exact solution of the two-dimensional Oberbeck-Boussinesq equations has been found in this paper. The solution is found in the case of the nonuniform distribution of velocities and a linear heat source at the upper boundary of an infinite layer of a viscous incompressible fluid. Analysis of polynomial solutions describing the natural fluid convection is presented. The existence of points at which hydrodynamic fields vanish inside the fluid layer is demonstrated. [ABSTRACT FROM AUTHOR]

Exact solutions for three-dimensional nonlinear flows of a viscous incompressible fluid are examined. These solutions belong to Lin’s class of solutions, which are velocities linearly dependent on a part of coordinates. This allows these solutions to be used for the description of large-scale currents of the World Ocean. The obtained exact solution describes the flow of a vertical vortex fluid. A vertical twist in the fluid arises from the consideration of inertia forces and the nonuniform velocity distribution on the free boundary of the fluid layer. This solution allows one to describe counterflows of an incompressible fluid for flows in a thin layer. Thus, the obtained exact solution of the Navier-Stokes equations describes a new mechanism of momentum transfer in a fluid. The obtained solutions are analyzed in this paper. The existence of stagnation points for the flow of a vertical vortex fluid in an infinite layer with permeable boundaries is shown. [ABSTRACT FROM AUTHOR]

In mechanical engineering, in particular, in the manufacture of parts for gas turbine installations and gas turbine engines with variable geometry – compressor and turbine blades, holes in disks, etc. – and complex shapes, it is necessary to control the level of residual stresses. When using the X-ray diffractometry method, it is necessary to ensure the position of the diffractometer collimator along the normal to the surface under investigation. For the specified parts, this condition is not always feasible. In this paper, the effect of the position of an X-ray diffractometer collimator relative to the measurement surface on the value of the measured residual stresses is estimated. Flat samples from steel 09G2S and alloy VZhL14 are used. The position of the collimator relative to the plane of the sample is determined by an angle α that is varied from 0° to 30° in steps of 5°. As a result of the measurements, the values of the measured residual stresses are compared with their value at 0° and the limiting angles are found, above which there is a substantial distortion of the measurement results. [ABSTRACT FROM AUTHOR]

The paper presents a computational model for the numerical study of the mechanical behavior of ceramics with an explicit account of its internal structure, namely, cylindrical pores differently oriented in space. The model utilizes the movable cellular automaton method for modeling deformation and fracture as dynamic processes occurring in the material under loading. We model uniaxial compression of several representative 3D cubic specimens with an explicit account of pores of the same size but with a unique position and orientation in space. As a result, we get the average values of Young’s modulus, Poisson’s ratio, and strength, as well as the parameters of the Weibull distribution of these properties of the model material. The analysis of the modeling results shows that the minimum values of mechanical properties is exhibited by the specimens with all cylindrical pores inclined at the angle of 45° to the loading direction. The randomization of the elongated pore orientation leads to higher mechanical properties. [ABSTRACT FROM AUTHOR]

This paper presents the results of a computational and experimental study of the stress-strain state of the frame of a reversing device under loading simulating the operational one. The study is conducted by using fiber-optic sensors and comparing the results with those obtained by the numerical simulation in the ANSYS software package. [ABSTRACT FROM AUTHOR]

The differential eigenvalue problem describing eigenvibrations of a simply supported beam with an attached load is investigated. This problem has an increasing sequence of positive simple eigenvalues with a limit point at infinity. To the sequence of eigenvalues, there corresponds a complete orthonormal system of eigenfunctions. We formulate a limit differential eigenvalue problem and prove the convergence of the eigenvalues and eigenfunctions of the initial problem to the corresponding eigenvalues and eigenfunctions of the limit problem as load mass tending to infinity. The original differential eigenvalue problem is approximated by the finite difference method on a uniform grid. Error estimates for approximate eigenvalues and eigenfunctions are established. The theoretical results are illustrated by numerical experiments for a model problem. Investigations of this paper can be extended to the cases of more complicated and important problems on eigenvibrations of plates and shells with attached loads. [ABSTRACT FROM AUTHOR]

The nonlinear second-order differential eigenvalue problem describing eigenvibrations of a bar with elastically attached load is investigated. The existence of an increasing sequence of positive simple eigenvalues with a limit point at infinity is established. To the sequence of eigenvalues, there corresponds a system of normalized eigenfunctions. The initial nonlinear differential eigenvalue problem is approximated by the finite element method on a uniform grid. The accuracy of approximate solutions is studied. The investigations in the present paper can be extended to the cases of more complicated and important problems on eigenvibrations of beams, plates, and shells with elastically attached loads. [ABSTRACT FROM AUTHOR]

This paper presents a state-of-the-art review of the problem concerning the estimation of the load-bearing capacity of piles driven in a soil body. The main advanced techniques and characteristic relationships of the dynamic response of piles, which are actively employed in pile foundation engineering, both abroad and in Russia, are described. A mathematical model for determining the bearing capacity of piles is proposed. The results of field and numerical experiments are presented. [ABSTRACT FROM AUTHOR]

Analytical solutions of the stationary shear convective flow of a rotating viscous incompressible fluid are obtained in this paper. The fluid flow is described by the Oberbeck-Boussinesq equations taking into account two Coriolis parameters. The velocity field is determined by the exact Eckman solution. The temperature field and the pressure field depend linearly on the longitudinal coordinates. The boundary value problem for a system of ordinary nonlinear differential equations is obtained after substitution in the original equations, the solution being obtained analytically. The solutions are analyzed. The effect of the second Coriolis parameter on the background pressure is shown. [ABSTRACT FROM AUTHOR]

The paper proposes an approach to determining the boundary of possible impact loads for a gasturbine locomotive cab involved in the collision with an obstacle, which would allow the cab to retain its necessary durability. This boundary defines the region of safe operation for the locomotive cab considering various parameters of locomotive movement. If the parameters of the movement and the obstacle lie within the region, the safety of personnel and equipment in the cab will be provided. [ABSTRACT FROM AUTHOR]

The problem of interaction of a liquid metal drop with a porous substrate is studied. The proposed model takes into account the capillary and adhesive properties of the melt. In this paper, numerical calculations of the influence of the concentration of nanopowder inoculators on the geometric dimensions of the formed splat (solidified liquid particle) and the depth of penetration of the liquid into the substrate are carried out on the basis of this model. [ABSTRACT FROM AUTHOR]

This paper deals with the development and approbation of a computational model of damage accumulation in a vertical steel tank at the non-uniform foundation subsidence. The object of research is structure behavior at the survivability stage, namely, the character and sequence of damage initiation and accumulation (elastic-plastic strain, bottom and wall buckling) in the tank structure. [ABSTRACT FROM AUTHOR]

In the present paper we show that for any fixed 1 < c < 31/17 there exist infinitely many consecutive cube-free numbers of the form [nc], [nc] + 1. [ABSTRACT FROM AUTHOR]

In the present paper we consider the Goursat problem, which appears to be closely related to construction of the so called copulas. Unlike the classical approach applied by Vladimirov [7] where he solves the two-variable problem we investigate the n-dimensional case. In addition to that we also prove that there exists a unique solution to the Goursat problem. [ABSTRACT FROM AUTHOR]

We give an interpretation of some recent results of Petrova for the Duffing equation ẍ(t) + δẋ(t) + αx(t) + βx³(t) = u(t). The common assumptions are that α, β and δ are positive constants and u(t) ∈ C([T, ∞); R), is a given function, T is a large enough constant. We apply MATLAB/Simulink and compare numerical results with these one of Petrova for the distributions of the zeros of the equation. In this paper, numerical results are given for the case, where β = 0, which situation corresponds to the linear case. [ABSTRACT FROM AUTHOR]

This paper focuses on the impact towards the performance of silicon nanowire field-effect transistor (SiNWFET) for biosensing application based on different channel lengths of the nanowire. A device numerical modelling tool, Silvaco ATLAS was used to design three p-type SiNW-FET biosensors with differentlengths of 0.5, 1.0, and 10.0 μm. The designed devices were simulated in order to observe and compare the effect of different channel length towards the electrical characteristic of the devices. Increase of the nanowire channel length had caused reduction of drain current, ID flowed through the channel from drain to source region. This is related to the increase of electrical resistance, R of the nanowire with the increase of nanowire length, L. In a way to study the effect of different channel lengths on the performance of the SiNW-FET biosensor, several negatively interfuce charge densities, QF (i.e. -0.1x1012, -0.5x 1012, and -1x1012 cm·2) were introduced on the surface of the SiNW channel to represent as the actual target deoxyribonucleic acid (DNA) captured by the bioreceptor of the biosensor. Based on the results, these negatively QF attracted the hole carriers below the surface of p-type nanowire to form an accumulation of charge carriers in the channel, causing an increase in the device output ID. Increase of the applied negative charge density had allowed for more ID to flow across the channel between drain and source region. The changes of ID with the applied Q F are utilized to determine the sensitivities and limit of detections (LOD) for all designed biosensor with different channel lengths. In comparison, the smallest nanowire length of 0.5 μm produced the highest sensitivity and lowest LOD of 2.17 μA/cm·2 and 7.85x 1010 cm·2, respectively, hence demonstrates better performance of SiNW-FET biosensor for the detection of specific charged DNA in analyte. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and numerical investigation on the flow modification in an air intake Sshaped aggressive diffuser. The selected diffuser has an actual geometry of 45o subsection from annular cross section, with implementing flow modifiers. The S-shaped diffuser had an area ratio 3.1 and turning angle of 35°/35°. The investigation is performed with three types of passive flow control flow modifiers. 3D CFD simulation was performed through ANSYS-FLUENT 15 software. The experimental results showed a good agreement with the numerical results. The measurements were conducted inside annular subsection at inlet Reynold number 40 × 104 and turbulence intensity 4.8%. The performance parameters, static pressure recovery and distortion coefficient, used for performance evaluation. Implementing flow modifiers type 2 gives maximum static pressure recovery of 0.77, 0.83 and minimum distortion coefficient of 0.086, 0.077 for experimental and numerical results, respectively. While the less improvement was produced with implementing flow modifiers type 3. [ABSTRACT FROM AUTHOR]

Various performance measures have been developed for performance evaluation of the stratified Thermal Energy Storage (TES) tank. There are many methods which have been developed including numerical, analytical to determine the TES tank efficiency using Figure of Merit (FOM) and Thermocline Thickness (WTC) parameters as the performance indicators. However, these methods are more complicated and need more technical data. Therefore, a simple and easy method is required to predict the performance of TES tank. In this paper, a comparative study using results from analytically solved sigmoid dose response function and artificial neural network (ANN) is conducted to determine the parameters. [ABSTRACT FROM AUTHOR]

In this paper we study the fourth order Boussinesq equation with a single nonlinearity. We rewrite this equation in a Hamiltonian form and present a noncompact finite difference scheme, which preserves the symplectic structure of the initial problem. We construct a new finite difference scheme, which is very similar to the symplectic scheme but preserves the discrete energy exactly. To illustrate both schemes we present many computational results. We compare the performance of the symplectic scheme with the new conservative finite difference scheme. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) is one of the contagious and deadly disease in the world. TB can mutate into Multidrug Resistance Tuberculosis (MDR-TB) if the patient does not start with an appropriate treatments. These two diseases can be modeled using system of ten-dimensional ordinary differential equation which represents 10 groups of individuals. Analytic and numerical analysis are done to explain the existence of equilibrium points and the basic reproduction number (R0) of the model. The analytic and numerical analysis results show that the disease free equilibrium point is locally asymptotically stable if (R01 < 1) and unstable if (R > 1). The level set of (R0) respect to interventions parameters is discussed to understand the sensitivity of each parameters to control the spread of TB and MDR-TB. In this paper, the model is also constructed as an optimal control problem with involving three control variables, such as BCG vaccination, treatment with first-line anti-TB drug, and treatment with second-line anti-TB drug. The aim of this problem is to minimize the number of infected individuals and also minimize cost of the controls that given. Optimal control derived using Pontryagin Minimum Principle and then solved numerically using the gradient descent method.The effectiveness of optimal control is exhibited by comparing the number of total infected individuals with and without optimal control. It has been observed that the optimal control strategy gives better result in minimizing the number of total infected individuals. [ABSTRACT FROM AUTHOR]

The most well-known technique or method in unconstrained optimization is the conjugate gradient method. It is used to get the greatest solution for the unconstrained optimization problems. This method is used in many fields especially, computer science, and engineering due to its convergence speed, simplicity, and the low memory requirements. A new modified conjugate gradient method is presented in this paper. This method is proved with the strong Wolfe-Powell (SWP) line search that it possesses sufficient descent property, and is globally convergent. Numerical results for a set of 141 test problems show the outperformance of the new proposed formula comparing with other methods using the same line search. The performance of this method is more efficient and better than the others. [ABSTRACT FROM AUTHOR]

Image blurring is one of the most crucial techniques in image processing and computer vision. The equation used for solving image blurring problem is known as anisotropic diffusion equation. It able to smooth the inner region of the image without blurring the significant part such as fine details and sharp edges. The main purpose of this paper is to examine the efficiency of Accelerated Over Relaxation (AOR) iterative method with two weighted parameters for solving image blurring problems. To do the performance analysis based on the number of iterations and computational time, three iterative methods which are Gauss-Seidel, Succesive Over Relaxation (SOR) and AOR had been examined to produce the same quality image of Jacobi iterative method. Based on numerical results of the experiments taken out, the findings have shown that AOR iteration is slightly better than Gauss-Seidel and SOR iteration in reducing the number of iterations and computational time approximately by 30% and 2% respectively. [ABSTRACT FROM AUTHOR]

Less attention was made to solve special second order stiff delay differential equations (DDEs) directly. In this paper, the development of direct predictor-corrector variable stepsize variable order (DBVSVO) method is described to solve special second order stiff DDEs directly without reducing to first order equations. The predictor and corrector formulae is derived based on backward differentiation formulae (BDF) and represented in divided difference form. In order to achieve greater efficiency, the developed method is implemented using variable stepsize variable order (VSVO) technique. Numerical results are presented to show that the developed method is suitable for solving special second order stiff DDEs. For comparison purposes the same set of test examples are reduced to a system of the first order equations and solved using predictor-corrector variable stepsize variable order method based on backward differentiation formulae (BVSVO) method proposed by Mohd Isa et al. [1]. [ABSTRACT FROM AUTHOR]

In this paper we generated a new procedure called interval midpoint zoro symmetric single-step IMZSS2-5D procedure which is an extension from the existing ISS2 procedure. This procedure needs some pre-conditions for the initial interval to converge to the zeros respectively, starting with some disjoint intervals, each of which contains a polynomial zero. The IMZSS2-5D will produce a set of intervals of smallest possible width such that each interval includes one or more zeros of the polynomial from a given initial interval. The efficiency of the procedure is measured based on the CPU times, number of iterations and the value of the intervals width after satisfying the convergence criterion. Six test polynomials are used to verify the procedure. The numerical results are obtained by using MATLAB. The results indicated that the IMZSS2-5D procedure outperformed the existing ISS2 procedure. Hence, it is efficient to use IMZSS2-5D procedure for simultaneously bounding the polynomial zeros. [ABSTRACT FROM AUTHOR]

In this paper, we deal with the application of Successive Over-Relaxation (SOR) iterative method for solving fuzzy Fredholm integral equations of the second kind (FFIE-2).In addition to that, we applythe trapezoidal rule to derive the approximate solution of FFIE-2 which consists of a system of integral equations. Next, the approximate equation is used to develop a system of linear equations. Then, we consider SOR iterative method to solve the generated system of linear equations. Next, SOR iterative method is implemented on some numerical examples. Finally, the numerical results is discussed in details by comparing the number of iterations, the computational time, and the Hausdorff distance to analyze the performance of proposed method. Based on the numerical results obtained from all the numerical examples by using Gauss-Seidel (GS) and SOR methods, it can be pointed out that SOR method is more efficient than the GS method. [ABSTRACT FROM AUTHOR]

In this paper, some elements of the theory of the Wright function φ are discussed. The Wright function-along with the Mittag-Leffler function-plays a prominent role in the theory of the partial differential equations of the fractional order that are actively used nowadays for modeling of many phenomena including e.g. the anomalous diffusion processes or in the theory of the complex systems. This function appears there simultaneously as a Green function in the initial-value problems for the model linear equations with the constant coefficients and as a special solution invariant under the groups of the scaling transformations of the fractional differential equations. In this paper, both of these applications are shortly introduced. Whereas the analytical theory of the Wright function is already more or less well developed, its numerical evaluation is still an area of the active research. In this paper, the numerical evaluation of the Wright function is discussed with a focus on the case of the real axis that is very important for applications. In particular, several approaches are presented including the method of series summation, integral representations, and asymptotical expansions. In different parts of the complex plane different numerical techniques are employed. In each case, estimates for accuracy of the computations are provided. [ABSTRACT FROM AUTHOR]

The paper proposes a numerical investigation based on RANS computation for solving the viscous flow around a ship podded propulsion unit. A set of computations has been performed to better understand the influences exerted by different configurations on the wake structure in the propeller disk in the pushing type case. The RANS computation method is employed to evaluate the flow field structure around the podded propulsion units and the forces acting on it. Hydrodynamic design podded system has not, so far, been fully established in the propeller-pod-strut system. It is necessary to use a reliable procedure in the design of such propulsion systems to increase the propulsion efficiency. In an attempt to meet these needs, the present paper introduces a numerical procedure to analyze the hydrodynamic performance of the propeller and steering system using a combined lifting line and RANS methods. [ABSTRACT FROM AUTHOR]

This paper concerns the efficient numerical solution of the time-dependent, three-dimensional Heston-Hull-White PDE for the fair prices of European call options. The numerical solution method described in this paper consists of a finite difference discretization on non-uniform spatial grids followed by an Alternating Direction Implicit scheme for the time discretization and extends the method recently proved effective by In’t Hout & Foulon (2010) for the simpler, two-dimensional Heston PDE. [ABSTRACT FROM AUTHOR]

This paper presents numerical study of flow behavior from a heated concentric annulus cylinder at various Rayleigh number Ra, Prandtl number Pr while the aspect ratio is fixed to 5.0 of the outer and inner cylinders. The Finite Different Lattice Boltzmann Method (FDLBM) numerical scheme is proposed to improve the computational efficiency and numerical stability of the conventional method. The proposed FELBM applied UTOPIA approach (third order accuracy in space) to study the temperature distribution and the vortex formation in the annulus cylinder. The comparison of the flow pattern and temperature distribution for every case via streamline, vortices and temperature distribution contour with published paper in literature were carried out for the validation purposes. Current investigation concluded that the UTOPIA FDLBM is an efficient approach for the current problem in hand and good agreement with the benchmark solution. [ABSTRACT FROM AUTHOR]

The development of a tidal current turbine that can extract maximum energy from the tidal current will be extremely beneficial for supplying continuous electric power. The present paper presents a conceptual design of a 100kW energy integrated type tidal current turbine for tidal power generation. The instantaneous power density of a flowing fluid incident on an underwater turbine is proportional to the cubic power of current velocity which is approximately 2.5m/s. A cross-flow turbine, provided with a nozzle and a diffuser, is designed and analyzed. The potential advantages of ducted and diffuser-augmented turbines were taken into consideration in order to achieve higher output at a relatively low speed. This study looks at a cross-flow turbine system which is placed in an augmentation channel to generate electricity bi-directionally. The compatibility of this turbine system is verified using a commercial CFD code, ANSYSCFX. This paper presents the results of the numerical analysis in terms of pressure, streaklines, velocity vectors and performance curves for energy integrated type bi-directional tidal current turbine (BDT) with augmentation. [ABSTRACT FROM AUTHOR]

This paper presents the boundary element method (BEM) algorithm for the 2D steady-state heat conduction problem of particulate composite in which a thermal boundary resistance exists at constituent interfaces. The numerical implementation of the boundary integral equations is based on linear elements after boundary discretization. BEM formulation which incorporates the imperfect interface effects is developed for steady 2D simulations of the temperature distributions of composites containing randomly distributed particles of different sizes. The randomly distributed particles investigated in this paper include circular particles and square particles with different orientations. The temperature distributions of steady-state conduction inside the composite are simulated using the present BEM formulation. Numerical examples for composite with different particle geometries are presented, which illustrate the accuracy, suitability and efficiency of the present BEM algorithm for the approximations of steady-state heat conduction under either perfect or imperfect interfacial thermal contact conditions. The main advantage of BEM compared with the conventional methods is that it significantly reduces the dimensionality of the problem, resulting in a comparatively smaller system of equations to be solved. Compared to available solutions obtained by other numerical method, it provides an efficient and powerful analytical tool for steady-state solutions of constituents, such as particles with thermal barrier resistance across interfaces. [ABSTRACT FROM AUTHOR]

The vehicle bogies of Shanghai metro line 1 began to crack just in the third year after the trains operated. More than 50 cracks occurred in the succeeding six year during the train operation. This paper evaluated the safety of the motorized bogies. First, the loading conditions imposed on the vehicle structure were calculated based on the measured data in service of the train, and compared with the original design load. Then, this paper calculated simulated the stress of the vehicle bogie by 3D FEM, and presented the distribution of every stress concentration point in Goodman fatigue diagram. The computational locations of the strength less than the safety are agreed with where cracks have happened. Finally, this paper calculated the fatigue life of the motor bracket of the bogie through S-N curve based on revised Miner theory. In conclusion, this paper think that the bogie cracks of Shanghai metro line 1 are contributed by the overburden fatigue load, and ignoring the lateral vibration load in the design of the vehicle bogie is the important cause that bogie cracks occurred far earlier than in the designed time. [ABSTRACT FROM AUTHOR]