bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation and Experimental Validation of Three-Dimensional Unsteady Multi-Phase Flow in Flushing Process of Toilets
Authors: Hu Jian Guo , Sun You Song , Zhang Zheng Rong
Published: October 2013

In order to predict the flush performances of digital toilet products before mass production, a numerical simulation for a three-dimensional unsteady multi-phase flow in the flushing process of a wash-down toilet is carried out by using FLUENT software. The finite volume method (FVM) is used to discrete the three governing equations in space and time. The discrete equations are solved by using the first-order upwind discretization scheme and the PISO pressure-velocity coupling scheme. The realizable turbulence model is chosen as the viscous model to treat the fluid flow with large bending curvature wall. The volume of fluid (VOF) model is applied to solve the transient free-surface problem. First, a two-phase flow was simulated on the assumption that there is not sewage but water in the trap seal. Then, by simplifying the mixture of sewage and water in the trap seal as the third phase with high viscosity, a three-phase flow was simulated. Moreover, in order to validate the simulated results, a flushing testing was conducted to test the flush range, and a target type flow meter was designed, calibrated and applied to test the flush velocity. The comparisons show a good agreement between the numerical and experimental results. Based on the verified simulation results, the flush performances of the digital wash-down toilet, such as flush range, flush velocity and sewage replacement ability, can be predicted and evaluated.
Buffeting Internal Force Response Analysis for Stable Type Suspension Bridge
Authors: Geng Meng Xi , Qu Ben Ning , Peng Jiao Long , Wang Xiao Chun
Published: October 2013

According to the definition of the Buffeting, it is caused by a fluctuating wind. Since fluctuating wind is wind speed changing with time in the atmosphere, it will cause the vibration of the structure. And pulsating wind reflects the atmospheric boundary layer wind disturbance and randomness. In the paper, Stable Type Suspension Bridge (STSB) is researched for buffeting problem. A finite element model of the bridge is set up using the finite element software. The buffeting response of the bridge is calculated and studied. The influence of the opposite tensional structures in the bridge on buffeting response of the bridge is assessed.
Combination of DES and DDES with a Correlation Based Transition Model
Authors: Qiao Lei , Bai Jun Qiang , Hua Jun , Wang Chen
Published: October 2013

The present article describes the combination of the correlation based transition model of Menter et al. with the Detached Eddy Simulation (DES) and Delayed Detached Eddy Simulation (DDES) methodology. The interaction between transition model and DES or DDES method was investigated by T3A test case. The grid sensitivity of the combined methodology is discussed and the resolution is given. Then, the simulation of flow over foil of medium thick at stall angle was performed. The combined methodology produce results that have better agreement with experiment comparing to RANS transition model or fully turbulent DES/DDES alone. And the DDES based combined model shows a better agreement with experiment in the simulation of trailing edge separation comparing to DES based combined model.
Aero-Acoustics Computations of Square Cylinder Using the Lattice Boltzmann Method
Authors: Si Hai Qing , Wang Bing , Shi Yan , Wu Xiao Jun
Published: October 2013

In this paper the ability of the Lattice Boltzmann Method (LBM) is investigated for simulating acoustic problems, especially for the propagation of acoustic waves in a wall bounded region. To treat the wall boundary conditions, a non-equilibrium extrapolation scheme for the LBM is adopted. LBM is next applied to simulate the complex aerodynamic noise generated from a square cylinder. In order to efficiently suppress the disturbances at the computational boundaries, the improved absorbing boundary condition (IABC) is developed in this paper. To validate the flow and acoustic solution of a square cylinder, comparisons between the present LBM and the previous studies are carried out. It is demonstrated that the LBM can efficiently simulate the noise generated from a square cylinder.
Prediction of Hydrodynamic Performance of Hydrofoil with Suction and Jet Equipment
Authors: Wang Chao , Xiong Ying , Wang Guo Liang , Guo Hai Peng
Published: October 2013

In order to improve the hydrodynamic performance of the hydrofoil, one new foil is brought forward which has slits near the leading edge and the trailing edge. In this article, the NACA0012 foil whose performance was calculated by CFD method was chose as a study object. And the validity of the CFD method was proved by contrasting the calculation results with the experiments. Through calculating and analyzing the hydrodynamic performance of the new hydrofoil that has suction inlet and jet outlet in the leading edge and the trailing edge respectively, the result shows that such performance of suction-jet hydrofoil has advantages of both suction hydrofoil and water-jet hydrofoil.
Multi-Body Contact Dynamics Analysis of Angular Contact Ball Bearing
Authors: Jin Kun Feng , Yao Ting Qiang
Published: October 2013

The 3-D multi-body contact dynamics simulation model was built by ADAMS base on the Hertz contact theory and multi-body contact dynamics, which considered the dynamics relationship among the ball, ring and cage of the bearing. Considering the clearancesfrictions and loads, results that contained deformation and displacement of the bearing, trajectory of the CM of the cage and the dynamic contact force were obtained by means of the 3-D multi-body contact dynamics model simulation and statics calculation. The outcomes got from two different methods are consistent, so the 3-D multi-body contact dynamics simulation model has the positive significance on dynamic design and engineering application of the bearing.
An Investigation on Numerical Simulation Method for Aero-Acoustics Based on Acoustics Analogy
Authors: Yang Dang Guo , Wu Yong Hang , Liang Jin Min , Liu Jun
Published: October 2013

A numerical simulation method on noise prediction, which incorporates aerodynamics and sound wave equations based on acoustic analogy, is presented in the paper. Near-field unsteady aerodynamic characteristic can be obtain by large eddy simulation (LES), and far-field propagation of sound waves and spatial sound-field can be obtain by solving the time-domain integral equations of Ffowcs Williams and Hawings (FW-H). Based on the method, a numerical simulation was done on a two-dimension cylinder and a three-dimension flat plate with blunt leading edge. The agreement of numerical results with experiment data validated the Feasibility of the method. The results also indicate that LES can describe vortex generation and shedding in the flow-fields, and FW-H formulation, which has taken time-lag between sound emission and reception times into account, can simulate time-effect of sound propagation toward far-fields.
Numerical Simulation of Unsteady Flow and Flow Induced Sound of Airfoil and Wing/Plate Junction by LES and FW-H Acoustic Analogy
Authors: Zhang Nan , Lv Shi Jin , Xie Hua , Zhang Sheng Li
Published: October 2013

Numerical simulation of unsteady flow and flow-induced sound of an airfoil and a wing/plate junction are performed in the paper by large eddy simulation (LES) and FW-H acoustic analogy. The vortical flows around a NACA0015 airfoil at two angles of attack (0°and 8°) are simulated and analyzed by vortex identification. Simultaneously, the wall pressure fluctuations of the airfoil are computed. At two angles of attack, the flow induced sound of the airfoil is predicted. The computed power spectra agree well with experimental measurements. So the capability of large eddy simulation in predicting unsteady flow and flow induced sound is validated. Subsequently, the horse-shoe vortex around a wing/plate junction in water is computed. Furthermore, the calculations of wall pressure fluctuations and flow induced sound of the junction model at three velocities are accomplished. The predicted results are compared favorably with measured data in large circulation water channel. So the numerical approach for flow induced sound of wing/plate junction in water is validated. It shows that the numerical simulation method in the paper is credible.
Numerical Simulation of Pressure Difference about Curve Ball in Flight
Authors: Zhang Xue , Cheng He Ming , Li Jian Yun , Zhou Si Qing , Yang Tie Xin
Published: October 2013

Life lies in movement, Football is now the most popular sport in the world. Fluent12.1 software is employed in this thesis to model the numerical simulation of the pressure which the ball with different angular velocity and different velocity bears. Simulation results show that the pressure difference on the surface of the ball with a certain speed will increase if the angular velocity increases. The pressure difference on the surface of the ball with a certain angular velocity will increase if the velocity increases. The radian of ball will become more bigger.
Two-Phase CFD Study of Coolant through a 5×5 Rod Bundles with Grid Spacers
Authors: Tan Shen Gen , Li Song Wei , Jiao Yong Jun , Lu Qing , Wang Guo Bin , Wang Zheng Yu
Published: October 2013

A numerical study using computational fluid dynamics (CFD) under air/water two-phase flow condition without thermal transmission is carried out utilizing the commercial CFD code CFX. A detailed geometry of 5×5 rod bundles with two grid spacers in the Pressurized Water Reactor (PWR) is set up for analyzing. The Multiple Size Group (MUSIG) model based on the population balance equation is employed to describe the characteristic of flow field in which the dispersed phase has a large variation in size, and the breakup and coalescence interaction among different sizes of the bubbles. The effects of the size fraction at inlet, the size group quantities, the breakup and coalescence coefficients, the momentum transfer model, and so on, are studied. The results demonstrate that various parameters and two-phase model have different impacts on the analysis results. The detailed CFD modeling methodology for two-phase flow conditions in PWR fuel assemblies is developed according to the above-mentioned investigations. The flow field patterns and air/water phase distributions in the computational results shows that the two-phase modeling methodology in the present work is reasonable.
Numerical Simulation on Backwater Downstream of Aerators in Spillway Tunnel with Ultra-Low Frounde Number Flow
Authors: Chen Li Qiang , Wang Jun Xing , Chen Yu Ting
Published: October 2013

The backtracking of flow occurs easily in cavity of aeration step in spillway tunnel with a gentle bottom slope and ultra-low Frounde number, and this influences the intake of air, so combined with the spillway tunnel of Chang heba Hydropower Station, four bodily form of aeration steps are chosen to be studied by both numerical simulation and model test based on κ-ε turbulence model, they are continuous aeration step, U-type aeration step + local steep slope, continuous aeration step + circular arc type steep slope and continuous aeration step + ogee curve steep slope, the results show that, the downstream bottom slope of aeration step with suitable ogee curve or circular arcs can efficiently inhibit the backtracking of flow in continuous aeration step, and can efficiently eliminate hydrops in cavity and in the same time can improve the efficiency of aeration. Usually, the results of bottom slope with an ogee curve are better than that with a circular arc.
Fluid-Structure Interaction Dynamics for Laminated Plate\Shell Topology Optimization
Authors: Ye Hong Ling , Li Yao Ming , Zhang Yan Ming , Sui Yun Kang
Published: October 2013

This paper focuses on Fluid-structure interaction dynamics for laminated plate\shell topology optimization. Based on ICM method, the filtering function of the element weight, the element mass matrix and the element stiffness matrix are established. Through Fluid-structure interaction boundary element integral formula, and Taylor expansion of Rayleigh quotient which is described by the filter function, the frequency constraint is approximately expressed as an explicit function and the mathematical formulation of the optimal problem refer to weight as objective and subject to multiple frequency constraints. Finally, the topology optimization problem is solved by dual sequence quadratic programming (DSQP). Numerical examples are provided to demonstrate the validity and effectiveness.
Large Eddy Simulation of Unsteady Flow in a Mixed Flow Pump Guide Vane
Authors: Li Yi Bin , Li Ren Nian , Wang Xiu Yong
Published: October 2013

In order to investigate the characteristics of unsteady flow in a mixed flow pump guide vane under the small flow conditions, several indicator points in a mixed flow pump guide vane was set, the three-dimensional unsteady turbulence numerical value of the mixed flow pump which is in the whole flow field will be calculated by means of the large eddy simulation (LES), sub-grid scale model and sliding mesh technology. The experimental results suggest that the large eddy simulation can estimate the positive slope characteristic of head & capacity curve. And the calculation results show that the pressure fluctuation coefficients of the middle section in guide vane inlet will decrease firstly and then increase. In guide vane outlet, the pressure fluctuation coefficients of section will be approximately axially symmetrical distribution. The pressure fluctuation minimum of section in guide vane inlet is above the middle location of the guide vane suction surface, and the pressure fluctuation minimum of section in which located the middle and outlet of guide vane. When it is under the small flow operating condition, the eddy scale of guide vane is larger, and the pressure fluctuation of the channel in guide vane being cyclical fluctuations obviously which leads to the area of eddy expanding to the whole channel from the suction side. The middle of the guide vane suction surface of the minimum amplitude pressure fluctuation to which the vortex core of eddy scale whose direction of fluids rotation is the same to impeller in the guide vane adhere.
Studies on Evaluation Methods of Medium-Term Inspection about Master Degree Thesis with Interval Number's Sorting Way
Authors: Bao Yu E , Bai Eer Dun
Published: October 2013

In the work of medium-term inspection evaluation about master degree thesis in colleges and universities, its only grade but no superior difference. In response to this situation, this paper uses bounded closed interval numbers geometric mean sorting method make pros and cons sorting to be in the same professional degree thesis, which can break out the bound of grade and make the work of medium-term inspection of master degree thesis become more perfect, fair and justice.
Simple but Efficient Method for Integrating 1/r Singularities
Authors: Liu Feng , Zheng Hong , Li Chun Guang
Published: October 2013

New integration schemes are presented for integrands with singularity of 1/r. We partition the element with a singular center into several triangles sharing the center. Then, a transformation between a standard square and each of the triangles is conducted. We prove such a transformation itself brings about the Jacobian with the factor r, leading to no need to introduce any other transformation. Both two-dimensional and three-dimensional cases are considered. Compared to the Duffy transformation, the proposed methods enjoy more excellent numerical properties. Numerical examples in elastic fracture are also presented to illustrate the performance of the new integration techniques.
On the Construction of Nonnegative 5×5 Matrices from Spectrum Data
Authors: Liu Zhi Bing , Tu Zhen , Xu Cheng Feng
Published: October 2013

This paper studies the construction problems of five order nonnegative matrices from spectrum data. Let be a list of complex numbers with . Necessary and sufficient conditions for the existence of an entry-wise nonnegative 5×5 matrix with spectrum are presented.
Simulation of Water Droplet Merging under Shock Wave Using Real Ghost Fluid Method
Authors: Shi Ru Chao , Xu Sheng Li , Zhang Ya Jun
Published: October 2013

This paper presents a 3D numerical simulation of water droplets merging under a given shock wave. We couple interpolation method to RGFM (Real Ghost Fluid Method) to improve the numerical accuracy of RGFM. The flow states of air-water interface are calculated by ARPS (approximate Riemann problem solver). Flow field is solved by Euler equation with fifth-order WENO spatial discretization and fourth-order R-K (Runge-Kutta) time discretization. We also employ fifth-order HJ-WENO to discretize level set equation to keep track of gas-liquid interface. Numerical results demonstrate that droplets shape has little change before merging and the merged droplet gradually becomes umbrella-shaped under the given shock wave. We verify that combination of RGFM with interpolation method has the property of reducing numerical error by comparing to the results without employment of interpolation method.
A High Accuracy Numerical Inversion Method in Solving the Sobolev Differential Equations
Authors: Wang Li , Zhang Lin
Published: October 2013

In the paper, by means of Laplace transform the Sobolev differential equations become to the elliptic differential equations, which can be solved by the fourth order finite difference equations in parallel. After getting the approximate solutions of the elliptic differential equations, we can achieve the numerical solutions with high accuracy for the Sobolev differential equations by using the Zakian inversion method. At last, we carry out one numerical experiment to indicate that the method in this paper is effective.
One Class Series Involving Reciprocals of Binominal Coefficients
Authors: Zhang Lai Ping , Ji Wan Hui
Published: October 2013

Using one known series, We can structure several new series of reciprocals of central binomial coefficients by splitting terms ,these new created denominator of series contain 1 to 4 factors of binomial coefficients. As the result of splitting terms, some identities of series of numbers values of reciprocals of binomial coefficients are given. The method of splitting terms offered in this paper is a new combinatorial an analysis way and elementary method to create new series.
Comparison of Two Sixth-Order Compact Finite Difference Schemes for Burgers' Equation
Authors: He Xiao Gang , Yang Ying , Zhang Ping , Zhang Xiao Hua
Published: October 2013

In this study, two sixth-order compact finite difference schemes have been considered for solving the Burgers equation. The main difference of these schemes lies in the calculation of second-order derivative terms, which is obtained by applying the first-order operator twice and the method of undetermined coefficients. The aim is to comparison these schemes in terms of computational accuracy for solving the Burgers equation with difference viscosity values, especially for very small viscosity values. The results show that both schemes achieve almost the same accuracy for large viscosity values and second method is more accurate for moderate viscosity values, but both schemes are failed for very small viscosity values. However, when both schemes coupled low-pass filter for very small viscosity values, both schemes can well inhibit the problem.
An Improved ID3 Algorithm
Authors: Li Ju Fang , Lei Jin Hui , Zhao Xiao Xia , Zhang Chang Chang , Han Xue Xue
Published: October 2013

ID3 algorithm is the earliest and most influential of decision tree algorithm. This paper discusses the basic idea and implementation methods of the ID3 algorithm. A new algorithm based on attribute similarity for multivalued bias of ID3 algorithm was proposed, and the experimental results proved that the improved algorithm has strong predictive accuracy and better understandability.
Global Attractor of the Liquid Helium-4 System in Hk Space
Authors: Hou Zhi Bo , Li Li Mei
Published: October 2013

In this paper, by using an iteration procedure, regularity estimates of the linear semi-groups and a generalized existence theorem of global attractor, we prove that the liquid helium-4 system possesses a global attractor in space for all , which attracts any bounded set of in the-norm.
An Analysis Method of Static Aeroelastic Response with Nonlinear Aerodynamic Data on 3D Bodysurface Panel Element
Authors: Wang Yao Kun , Wan Zhi Qiang , Liu Shan
Published: October 2013

A static aeroelastic responses analysis method based on mapping external nonlinear aerodynamic forces onto 3D body surface panel elements is proposed. The external nonlinear aerodynamic force data can be obtained by Euler solver, Navier-Stokes solver and wind tunnel tests. In this paper, the method is applied to obtain static aeroelastic responses of a flexible aircraft, and the emphasis is placed on the change of aerodynamic coefficient, aerodynamic pressure distribution and flight load. The results are compared with static aeroelastic responses calculated by high-order panel method. It is concluded that the method presented in this study is feasible, credible and efficient, and can provide an assessment of static aeroelastic response characteristics for the detailed stage of aircraft design.
A Simple Numerical Simulation Method for Lorenz System Families
Authors: Zhang Cheng Li , Zeng Yun
Published: October 2013

Lorenz system families contain Lorenz system, Chen system and Lu system, their accurate analytical solutions are not yet obtained now. The segmenting recursion method was put forward in this paper, the equations of Lorenz system families were reasonably linearized within small segment, the recursion formulas were obtained by solving the approximate analytical solutions within small segment, and all numerical solutions were got by the recursion formulas. The chaotic motion of Lorenz system families were numerically simulated by means of the segmenting recursion method, the simulation results were compared with Runge-Kutta method. The comparative results show that the segmenting recursion method is very effective to numerically simulate Lorenz system families, not only method is simple, programming is easy, but result is accurate. this method is a universal new method to numerically simulate similar system.
Stability of Subharmonic Oscillations in a Pipe Conveying Fluid under Harmonic Excitation
Authors: Geng Yi Xiang , Liu Han Ze
Published: October 2013

The existence and stability of subharmonic oscillations in a two end-fixed fluid conveying pipe whose base is subjected to a harmonic excitation are investigated. A Galerkin approach is utilized to reduce the equation of motion to a second order nonlinear differential equation. The conditions for the existence of subharmonic oscillations are given by using Melnikov method. The stability of subharmonic oscillations is discussed in detail by using action-angle variable and averaging method. It is shown that the velocity of fluid plays an important role in the stability of subharmonic oscillations.
An Efficient Surrogate Model Construction Strategy for Large-Scale Output Problems
Authors: Bai Jun Qiang , Qiu Ya Song , Qiao Lei
Published: October 2013

Applying common surrogate models to problems have numerous output variables is computational expensive, since the number of surrogate models should be constructed equals to the number of output variables. This paper presents an efficient strategy to solve this problem. For that, snapshot Proper Orthogonal Decomposition (POD) is used to extract a few main basis modes from certain number of samples. The predicted result of a large-scale output problem comes from the linear superposition of these basis modes. Common surrogate models just need to predict the coefficients for these basis modes. Through this strategy, The Mach numbers at 36864 points around an airfoil are predicted by just constructing 12 kriging surrogate models. The predicted Mach number distributions fit with the CFD results very well, that proves the efficiency of this strategy.
Analysis on Cracking Cause and Propagation Trend of Concrete Dam
Authors: Chen Qin , Gong Ya Qi , Qi Yong Feng
Published: October 2013

Some cracks are observed in a heightening project of a concrete gravity. In order to investigate and solve this problem, the three-dimensional finite element simulation and nonlinear cracking analysis are implemented in this paper to analyze the causes of cracks and their propagation trends. This work is helpful to design the proper crack controlling plans. The research shows that large tensile stress has accumulated during construction, especially after an early air temperature sudden drop in November, the tensile stress increases 3MPa in general on the concrete surface, which exceeds the tensile strength of concrete and causes cracking. Therefore, the crack is the result of both the accumulated temperature stress during construction and temperature sudden drop. The crack will further propagate during another temperature sudden drop, but extended range is limited. If concrete tensile strength is greater than 2.5MPa, the cracks will not penetrate throughout the dam body along the water flow direction.
Time-Accurate Simulation of the Aircraft External Store Separation
Authors: Di Ya Chao , Gao Ge , Xu Jing Lei , Shao Xing Chen , Yang Qing
Published: October 2013

Based on the original unsteady simulation program, the transonic aircraft external store separation was simulated by structured chimera grid approach coupled with a six degree of freedom trajectory code. The chimera grid utilized the hole-map cutting method; the searching efficiency was compared between the stencil walk and inverse map when building interpolation during the procedure. The space format utilized flux difference splitting format FDS based on Roe, moreover adding the min-mod limiter to achieve second order accuracy. The time format utilized the implicit integration and discrete scheme of the Back-Euler method. The three-dimensional trajectory of the store was captured and better fit for the experimental data. The results show that the method is correct and provides a reference for the simulation of the unsteady multi-body separation.
Macroscopic Modeling of Pedestrian Flow Considering the Herd Behavior
Authors: Jiang Yan Qun
Published: October 2013

This paper aims to mimic the herd behavior of pedestrian flow, i.e., the tendency towards majority when a congestion occurs, by macroscopic modeling approach. The macroscopic pedestrian simulation model is composed of a mass-conservation equation and a simple model to reflect behavioral characteristics of pedestrians based on a specific traffic situation. Numerical experiments are designed to show some preliminary results, e.g. the beneficial effect of herding on evacuation time in some situations.
Static and Dynamic Analysis of Intake Tower Structure
Authors: Jiang Yong Xing , Yue Jin Chao , Ye Ling Min
Published: October 2013

Taking intake tower of Hydropower Station project for an example, ANSYS is used on the intake tower dynamic, static analysis, to study the distribution of stress and displacement as well as structural stability. The results show that, under load, the deformation and stability of the intake tower to meet the structural design requirements, need to take special measures in the weak parts of the internal forces in the structural design. The results in this paper may be served as the basis of structure design of the intake tower.
Study on Parallel Computing Method of 3-D Dynamic Analysis of Large-Scale Structure
Authors: Lan Ri Qing , Feng Biao
Published: October 2013

In order to solve 3-D dynamic problem for large-scale structure, based on HDDM (Hierarchical Domain Decomposition Method) method, 3-D dynamic finite element parallel computing method of large-scale structure is studied. In this paper, BDD method and Newmark-β average acceleration method in time integration is used. Based on ADVENTRUE program, the corresponding linear implicit transient dynamic parallel program which is based on the MPI parallel environment and can be used in shared memory and distributed memory parallel computer is prepared. Several pre-conditioners are contrasted using some examples, and the results show that BDD preconditioner or BDD-DIAG preconditioner can be used in 3-D dynamic analysis for large-scale structure.
Study on Management and Control of Radar Based on Genetic Algorithms
Authors: Lei Ming , Xu Jin
Published: October 2013

Based on an in-depth study on warning area security of radar network, this paper sets the cost of radar networks overall operation as the objective function and proposes mathematical models for management and control of radar under circumstances with interference, aiming at accomplish the security mission within warning area on the basis of the constraint condition that the warning areas at different height can satisfy joint probability of detection and coefficient of radar coverage. We use a modified genetic algorithm for the calculation of radar management and control model, save the feature of the optimized individuals via defining the probability, and improve the algorithm through setting reasonable parameter. The simulation calculation and practical application prove that the model and the scheme are effective because the qualified rate of radar management and control meet the requirement (reaches 100% from 36.54% with the increment of 63.46%), the number of operational radar reduced, and the anti-jamming measures are reasonable.
Fluid Dynamic Simulations on Polysilicon Production
Authors: Nie Zhi Feng , Xie Gang , Hou Yan Qing , Cui Yan , Li Rong Xing , Yu Zhan Lian
Published: October 2013

Numerical simulations of transport phenomena is one of the valid methods in investigation of crystal silicon growth by CVD for various types of reactors. The present review provides the key summary on the development of fluid dynamic simulations on polysilicon of CVD and hopefully aid in future improvement of this technology. In the solution of CVD reactor models for polysilicon production, the influence of the deposition process on temperature, the transport phenomena and the surface reactions have to be taken into account when discussing the silicon growth rate.
The Numerical Simulation of Shaped Charge Jet under the Influence of Charge Structure
Authors: Qu Hong Fei , Han Feng , Chen Fang
Published: October 2013

In this article, through numerical simulation mechanic we investigated that charge structure, exploiting distinct radial detonation velocity explosives, has a remarkable influence on the forming process of shaped charge jet. Based on the numerical computational results, the contribution of charge proportion and filling mode to the shape and velocity of shaped charge jet are mainly analyzed, aiming to identify the best charge proportion. It is demonstrated from numerical experiments that, sub-munitions power is significantly enhanced premised on invariable size of sub-munitions. And this observation can be adopted to design of the warhead arrayed in net in the future.
An Insidious Cardiac Sarcoma Presenting with Progressive Neurologic Dysfunction
Authors: Pasalic Dario , Hegerova Livia T. , Gonsalves Wilson I. , Robinson Steven
Published: October 2013

Central nervous system metastases as the presentation of primary cardiac sarcoma are a very rare entity, with only a few previously reported cases. Sarcomas specifically make up 10 to 20% of all primary cardiac tumors. Patients with primary cardiac tumors typically present with cardiac symptomatology that may include arrhythmias, obstruction to blood flow and valve function, or symptoms of heart failure. We report a unique case of a patient with a primary cardiac sarcoma who presented with progressive neurologic dysfunction secondary to brain metastases without any preceding cardiac symptoms. We describe our novel management of these unique cases and discuss the current medical and surgical approaches to treating neurologic metastases from cardiac sarcoma.
Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate
Authors: Masubelele Mmoto L. , Hoffman Michael T. , Bond William , Burdett Peter
Published: October 2013

Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.
Frequency variations of gravity waves interacting with a time-varying tide
Authors: Huang C. M. , Zhang S. D. , Yi F. , Huang K. M. , Zhang Y. H. , Gan Q. , Gong Y.
Published: October 2013

Abstract. Using a nonlinear, 2-D time-dependent numerical model, we simulate the propagation of gravity waves (GWs) in a time-varying tide. Our simulations show that when a GW packet propagates in a time-varying tidal-wind environment, not only its intrinsic frequency but also its ground-based frequency would change significantly. The tidal horizontal-wind acceleration dominates the GW frequency variation. Positive (negative) accelerations induce frequency increases (decreases) with time. More interestingly, tidal-wind acceleration near the critical layers always causes the GW frequency to increase, which may partially explain the observations that high-frequency GW components are more dominant in the middle and upper atmosphere than in the lower atmosphere. The combination of the increased ground-based frequency of propagating GWs in a time-varying tidal-wind field and the transient nature of the critical layer induced by a time-varying tidal zonal wind creates favorable conditions for GWs to penetrate their originally expected critical layers. Consequently, GWs have an impact on the background atmosphere at much higher altitudes than expected, which indicates that the dynamical effects of tidal–GW interactions are more complicated than usually taken into account by GW parameterizations in global models.
Differential effects of extreme drought on production and respiration: synthesis and modeling analysis
Authors: Shi Z. , Thomey M. L. , Mowll W. , Litvak M. , Brunsell N. A. , Collins S. L. , Pockman W. T. , Smith M. D. , Knapp A. K. , Luo Y.
Published: October 2013

Abstract. Extremes in climate may severely impact ecosystem structure and function, with both the magnitude and rate of response differing among ecosystem types and processes. We conducted a modeling analysis of the effects of extreme drought on two key ecosystem processes, production and respiration, and to provide broader context we complemented this with a synthesis of published results across multiple ecosystems. The synthesis indicated that across a broad range of biomes gross primary production (GPP) generally was more sensitive to extreme drought (defined as proportional reduction relative to average rainfall periods) than was ecosystem respiration (ER). Furthermore, this differential sensitivity between production and respiration increased as drought severity increased. The modeling analysis was designed to better understand the mechanisms underlying this pattern and focused on four grassland sites arrayed across the Great Plains, USA. Model results consistently showed that net primary productivity (NPP) was reduced more than heterotrophic respiration (Rh) by extreme drought (i.e., 67% reduction in annual ambient rainfall) at all four study sites. The sensitivity of NPP to drought was directly attributable to rainfall amount, whereas sensitivity of Rh to drought was driven by both soil drying and a drought-induced reduction in soil carbon (C) content, a much slower process. However, differences in reductions in NPP and Rh diminished as extreme drought continued due to a gradual decline in the soil C pool leading to further reductions in Rh. We also varied the way in which drought was imposed in the modeling analysis, either as reductions in rainfall event size (ESR) or by reducing rainfall event number (REN). Modeled NPP and Rh decreased more by ESR than REN at the two relatively mesic sites but less so at the two xeric sites. Our findings suggest that responses of production and respiration differ in magnitude, occur on different timescales and are affected by different mechanisms under extreme, prolonged drought.
Extreme dissolved organic nitrogen fluxes in the human impacted Pamba River, Kerala, India
Authors: Elizabeth David S. , Jennerjahn T. C.
Published: October 2013

Abstract. Cultural eutrophication of coastal aquatic systems is a major undesired phenomenon of today, which is mainly ascribed to the application of inorganic fertilizers in agriculture. Consequently, dissolved inorganic nitrogen (DIN) is considered the major problem and widely studied. However, human interventions also strongly influence the riverine dissolved organic nitrogen (DON) concentrations and fluxes. Studies of nutrient inputs from tropical river catchments are biased towards DIN, even though they account for only a portion of the total dissolved nitrogen (TDN) pool, whereas the rest is comprised of DON and has been largely ignored. The tropical Pamba River was studied because of its manifold human activities in the catchment and was sampled during the south west monsoon (SWM), north east monsoon (NEM) and the pre monsoon (PM) months during 2010 to 2013. The largest pilgrim center on earth, the Sabarimala temple, located in the upstream forest is a unique feature of the catchment. Fertilizer application, livestock farming and inadequate sewage treatment are the prevailing land use practices. The goals of this study were to (i) define cause-effect relationships by assessing the effect of various human interventions such as the pilgrims, agriculture and sewage disposal in combination with the seasonal variations in hydrology on the DON concentrations and fluxes and to (ii) quantify the inputs from respective land use segments. The global maximum DON concentration (29 302 μM) was measured for the Pamba River. Pilgrim activities, high population density, agricultural and livestock farming as well as the lack of infrastructure for sanitation facilities were the cause for extremely high DON concentrations and fluxes in the plantation and settlement with mixed tree crop (SMT) segments. A DON yield of 745 kg ha−1 yr−1 was calculated for the Pamba catchment. The total DON inputs from all quantifiable sources amounted to 514 kg ha−1 yr−1 comprising of 69% of the total Pamba DON yield. In the Pamba River, sewage is the major source of DON and the unique Sabarimala pilgrim event accounts for most of it. Nevertheless, sewage input from the rest of the densely-populated catchment is high, which is a common feature of developing countries that lack adequate sanitation and water technology, i.e. in South and Southeast Asia and tropical Africa. Our study shows that DON makes up a significant portion of anthropogenic nitrogen in rivers, in particular in those regions, which are, however, scarce in respective data. It underscores the need for more quantitative studies from densely-populated tropical river catchments in order to improve global nitrogen budgets and the assessment of the consequences of anthropogenic nitrogen inputs into coastal aquatic systems.
School-based Telerehabilitation In Occupational Therapy: Using Telerehabilitation Technologies to Promote Improvements in Student Performance
Authors: Criss Melanie Joy
Published: October 2013

This article discusses the use of telerehabilitation technologies in occupational therapy for school-based practice. Telerehabilitation, for the purpose of this program, included the implementation of occupational therapy services via two-way interactive videoconferencing technology. The subjects included in this pilot program were children, ages 6 to 11 years, who attended an online charter school and had difficulties in the areas of fine motor and/or visual motor skills which impacted success with handwriting. Each participant completed a virtual evaluation and six 30-minute intervention sessions. The Print Tool™ Assessment was used to determine progress pre- and post-program. A learning coach/student satisfaction survey was given at the end of the program to determine participant satisfaction. Outcomes revealed improvements in handwriting performance for most students who participated in the program and high satisfaction rates reported by all participants.
Outcomes of Clinicians, Caregivers, Family Members and Adults with Spina Bifida Regarding Receptivity to use of the iMHere mHealth Solution to Promote Wellness
Authors: Fairman Andrea D. , Dicianno Brad E. , Datt Nicole , Garver Amanda , Parmanto Bambang , McCue Michael
Published: October 2013

The purpose of this study was to gather information regarding the receptivity of clinicians, caregivers and family members, and adults with spina bifida (SB) to the use of a mHealth application, iMobile Health and Rehabilitation (iMHere) system. Surveys were administered to end user groups in conjunction with a conference presentation at the Spina Bifida Association’s 38th Annual Conference. The survey results were obtained from a total of 107 respondents. Likert scale and qualitative results are provided in consideration of future application of the iMHere system in clinical practice. The results of this survey indicate respondents were receptive and supportive with regard to adopting such a system for personal and professional use. Challenges likely to be encountered in the introduction of the iMHere system are also revealed and discussed.
The Quest for Competitive Advantage in Global Supply Chains:
Authors: Manuj Ila , Omar Ayman , Yazdanparast Atefeh
Published: October 2013

The purpose of this article is to review literature on interorganizational learning (IOL) and related constructs systematically to develop a theoretical model of IOL. An extensive and systematic literature review was undertaken in major logistics, supply chain, operations, and strategic management journals to identify theories in which a model of IOL could be grounded and to document major relationships related to the concepts of organizational learning and IOL. Using resource-based view, relational view, and knowledge-based view as the theoretical foundations, a conceptual model depicting IOL as a source of a competitive advantage was developed. The proposed theoretical framework suggests IOL can be used to develop capabilities such as innovation and flexibility that, in turn, lead to higher levels of logistics performance and contribute to a firm's competitive advantage. Supply chain orientation is an important antecedent to IOL, and cultural distance is an important moderator of IOL. This article contributes to the body of knowledge on IOL by positioning IOL within the framework of received theories and constructs. Implications for managers and several directions for future research are also identified.
The Effect of Logistics Service Quality on Customer Loyalty through Relationship Quality in the Container Shipping Context
Authors: Jang Hyun Mi , Marlow Peter B. , Mitroussi Kyriaki
Published: October 2013

The objective of this research is to explore the role of logistics service quality in generating shipper loyalty, considering relationship quality in the unique context of container shipping. This is to fill the gaps revealed in the current understanding of ocean carrier–shipper relationships, particularly the lack of studies attempting to investigate shippers' future intentions to use the same carrier as opposed to the previous studies that focused on carrier selection criteria or on shippers' satisfaction with the service attributes. Soft concepts such as customer loyalty and logistics service quality have been increasingly explored in a variety of industries to offer further insight into the relationship issues. However, it was discovered that relatively few studies on this topic have been conducted in the context of maritime transport. The theoretical model is tested on data collected through a postal questionnaire survey of 227 freight forwarders in South Korea. Structural equation modeling (SEM) is employed to rigorously examine relationships among the extensive set of key variables simultaneously in a holistic manner. The findings demonstrate that container shipping lines should develop a high level of logistics service quality as well as relationship quality in order to attain higher (beyond mere satisfaction) levels of shippers' loyalty.
Seizures, Cerebral Shutdown, and SUDEP
Authors: Bozorgi Alireza , Lhatoo Samden D.
Published: October 2013

Several potential pathophysiologic phenomena, including “cerebral shutdown,” are postulated to be responsible for SUDEP. Since the evidence for a seizure-related mechanism is strong, a poor understanding of the physiology of human seizure termination is a major handicap. However, rather than a failure of a single homeostatic mechanism, such as postictal arousal, it may be a “perfect storm” created by the lining up of a several factors that lead to death.