Generation and application of the equations of condition for high order Runge-Kutta methods
NASA Technical Reports Server (NTRS)
Haley, D. C.
1972-01-01
This thesis develops the equations of condition necessary for determining the coefficients for Runge-Kutta methods used in the solution of ordinary differential equations. The equations of condition are developed for Runge-Kutta methods of order four through order nine. Once developed, these equations are used in a comparison of the local truncation errors for several sets of Runge-Kutta coefficients for methods of order three up through methods of order eight.
Optimized fourth-order Runge-Kutta method for solving oscillatory problems
NASA Astrophysics Data System (ADS)
Hussain, Kasim; Ismail, Fudziah; Senu, Norazak; Rabiei, Faranak
2016-06-01
In this article, we develop a Runge-Kutta method with invalidation of phase lag, phase lag's derivatives and amplification error to solve second-order initial value problem (IVP) with oscillating solutions. The new method depends on the explicit Runge-Kutta method of algebraic order four. Numerical tests from its implementation to well-known oscillatory problems illustrate the robustness and competence of the new method as compared to the well-known Runge-Kutta methods in the scientific literature.
Diagonally Implicit Symplectic Runge-Kutta Methods with High Algebraic and Dispersion Order
Cong, Y. H.; Jiang, C. X.
2014-01-01
The numerical integration of Hamiltonian systems with oscillating solutions is considered in this paper. A diagonally implicit symplectic nine-stages Runge-Kutta method with algebraic order 6 and dispersion order 8 is presented. Numerical experiments with some Hamiltonian oscillatory problems are presented to show the proposed method is as competitive as the existing same type Runge-Kutta methods. PMID:24977178
Optimal error estimates for high order Runge-Kutta methods applied to evolutionary equations
McKinney, W.R.
1989-01-01
Fully discrete approximations to 1-periodic solutions of the Generalized Korteweg de-Vries and the Cahn-Hilliard equations are analyzed. These approximations are generated by an Implicit Runge-Kutta method for the temporal discretization and a Galerkin Finite Element method for the spatial discretization. Furthermore, these approximations may be of arbitrarily high order. In particular, it is shown that the well-known order reduction phenomenon afflicting Implicit Runge Kutta methods does not occur. Numerical results supporting these optimal error estimates for the Korteweg-de Vries equation and indicating the existence of a slow motion manifold for the Cahn-Hilliard equation are also provided.
Third-order 2N-storage Runge-Kutta schemes with error control
NASA Technical Reports Server (NTRS)
Carpenter, Mark H.; Kennedy, Christopher A.
1994-01-01
A family of four-stage third-order explicit Runge-Kutta schemes is derived that requires only two storage locations and has desirable stability characteristics. Error control is achieved by embedding a second-order scheme within the four-stage procedure. Certain schemes are identified that are as efficient and accurate as conventional embedded schemes of comparable order and require fewer storage locations.
Symbolic Derivation of Order Conditions for Runge-Kutta-Nyström Methods
NASA Astrophysics Data System (ADS)
Vlachos, D. S.; Simos, T. E.
2007-09-01
The theory of bi-coloured trees and some special properties of Runge-Kutta-Nyström methods are used to construct a simple algorithm for the symbolic derivation of the order conditions. The basic assumption is that there is a certain connection between the elementary weights of trees with black and white roots, which reduces the number of conditions only to those that are derived from trees with white roots. This connection is compatible with symplecticity.
Equations of condition for high order Runge-Kutta-Nystrom formulae
NASA Technical Reports Server (NTRS)
Bettis, D. G.
1974-01-01
Derivation of the equations of condition of order eight for a general system of second-order differential equations approximated by the basic Runge-Kutta-Nystrom algorithm. For this general case, the number of equations of condition is considerably larger than for the special case where the first derivative is not present. Specifically, it is shown that, for orders two through eight, the number of equations for each order is 1, 1, 1, 2, 3, 5, and 9 for the special case and is 1, 1, 2, 5, 13, 34, and 95 for the general case.
NASA Astrophysics Data System (ADS)
Demba, Musa A.; Senu, Norazak; Ismail, Fudziah
2016-06-01
In this work, a new fourth order four stage explicit trigonometrically-fitted Runge-Kutta-Nyström (ETFRKN) method for the numerical solution of second order initial value problems with periodic solutions based on Simos technique is constructed. The numerical results show the efficiency of the new method in comparison with other existing methods.
Evolutionary generation of high order Runge - Kutta - Nyström type pairs for solving y(4) = f (x,y)
NASA Astrophysics Data System (ADS)
Famelis, I. Th.; Tsitmidelis, S.; Tsitouras, Ch.
2016-06-01
We present a new Runge - Kutta - Nyström type pair of orders 8(6) for the solution of a special fourth order initial value problem. To achieve this, a set of non - linear equations is solved using differential evolution technique.
Scaled Runge-Kutta algorithms for handling dense output
NASA Technical Reports Server (NTRS)
Horn, M. K.
1981-01-01
Low order Runge-Kutta algorithms are developed which determine the solution of a system of ordinary differential equations at any point within a given integration step, as well as at the end of each step. The scaled Runge-Kutta methods are designed to be used with existing Runge-Kutta formulas, using the derivative evaluations of these defining algorithms as the core of the system. For a slight increase in computing time, the solution may be generated within the integration step, improving the efficiency of the Runge-Kutta algorithms, since the step length need no longer be severely reduced to coincide with the desired output point. Scaled Runge-Kutta algorithms are presented for orders 3 through 5, along with accuracy comparisons between the defining algorithms and their scaled versions for a test problem.
NASA Astrophysics Data System (ADS)
Zhang, Chao-Yuan; Ma, Xiao; Yang, Lei; Song, Guo-Jie
2014-03-01
We propose a symplectic partitioned Runge-Kutta (SPRK) method with eighth-order spatial accuracy based on the extended Hamiltonian system of the acoustic wave equation. Known as the eighth-order NSPRK method, this technique uses an eighth-order accurate nearly analytic discrete (NAD) operator to discretize high-order spatial differential operators and employs a second-order SPRK method to discretize temporal derivatives. The stability criteria and numerical dispersion relations of the eighth-order NSPRK method are given by a semi-analytical method and are tested by numerical experiments. We also show the differences of the numerical dispersions between the eighth-order NSPRK method and conventional numerical methods such as the fourth-order NSPRK method, the eighth-order Lax-Wendroff correction (LWC) method and the eighth-order staggered-grid (SG) method. The result shows that the ability of the eighth-order NSPRK method to suppress the numerical dispersion is obviously superior to that of the conventional numerical methods. In the same computational environment, to eliminate visible numerical dispersions, the eighth-order NSPRK is approximately 2.5 times faster than the fourth-order NSPRK and 3.4 times faster than the fourth-order SPRK, and the memory requirement is only approximately 47.17% of the fourth-order NSPRK method and 49.41 % of the fourth-order SPRK method, which indicates the highest computational efficiency. Modeling examples for the two-layer models such as the heterogeneous and Marmousi models show that the wavefields generated by the eighth-order NSPRK method are very clear with no visible numerical dispersion. These numerical experiments illustrate that the eighth-order NSPRK method can effectively suppress numerical dispersion when coarse grids are adopted. Therefore, this method can greatly decrease computer memory requirement and accelerate the forward modeling productivity. In general, the eighth-order NSPRK method has tremendous potential
Explicit Runge-Kutta method with trigonometrically-fitted for solving first order ODEs
NASA Astrophysics Data System (ADS)
Fawzi, Firas Adel; Senu, N.; Ismail, F.; Majid, Z. A.
2016-06-01
In this note, an explicit trigonometrically-fitted (RK) method is developed to determine the approximate solution of the first-order IVPs with oscillatory solution. The proposed method solves first order ODEs by first converting the second order ODEs to an equivalent first order; which is based on the RK method of order four. The numerical experiment performed shows the efficacy of our newly developed method.
NASA Astrophysics Data System (ADS)
Simos, T. E.; Aguiar, Jesus Vigo
In this paper, a new approach for developing efficient Runge-Kutta-Nyström methods is introduced. This new approach is based on the requirement of annihilation of the phase-lag (i.e., the phase-lag is of order infinity) and on a modification of Runge-Kutta-Nyström methods. Based on this approach, a new modified Runge-Kutta-Nyström fourth algebraic order method is developed for the numerical solution of Schrödinger equation and related problems. The new method has phase-lag of order infinity and extended interval of periodicity. Numerical illustrations on the radial Schrödinger equation and related problems with oscillating solutions indicate that the new method is more efficient than older ones.
Galerkin/Runge-Kutta discretizations for semilinear parabolic equations
NASA Technical Reports Server (NTRS)
Keeling, Stephen L.
1987-01-01
A new class of fully discrete Galerkin/Runge-Kutta methods is constructed and analyzed for semilinear parabolic initial boundary value problems. Unlike any classical counterpart, this class offers arbitrarily high, optimal order convergence. In support of this claim, error estimates are proved, and computational results are presented. Furthermore, it is noted that special Runge-Kutta methods allow computations to be performed in parallel so that the final execution time can be reduced to that of a low order method.
Functional continuous Runge-Kutta methods for special systems
NASA Astrophysics Data System (ADS)
Eremin, A. S.; Olemskoy, I. V.
2016-06-01
We consider here numerical methods for systems of retarded functional differential equations of two equations in which the right-hand sides are cross-dependent of the unknown functions, i.e. the derivatives of unknowns don't depend on the same unknowns. It is shown that using the special structure of the system one can construct functional continuous methods of Runge-Kutta type with fewer stages than it is necessary in case of general Runge-Kutta functional continuous methods. Order conditions and example methods of orders three and four are presented. Test problems are solved, demonstrating the declared convergence order of the new methods.
NASA Astrophysics Data System (ADS)
Kazemi-Kamyab, V.; van Zuijlen, A. H.; Bijl, H.
2014-09-01
Thermal interaction of fluids and solids, or conjugate heat transfer (CHT), is encountered in many engineering applications. Since time-accurate computations of unsteady CHT can be computationally demanding, we consider the use of high order implicit time integration schemes which have the potential to be more efficient relative to the commonly used second order implicit schemes. We present a strongly-coupled solution algorithm where the high order L-stable explicit first-stage singly diagonally implicit Runge-Kutta (ESDIRK) schemes are used to advance the solution in time within each separate fluid and solid subdomains. Furthermore, the stability and rate of convergence of performing (Gauss-Seidel) subiterations at each stage of the ESDIRK schemes are analyzed. The results from solving a numerical example (an unsteady conjugate natural convection in an enclosure) show good agreement with the performed analytical stability analysis. In addition, the (computational) work-(temporal) precision character of several schemes in solving a strongly coupled CHT problem is compared over a range of accuracy requirements. From the efficiency investigation, it is observed that performing subiterations with the strongly-coupled ESDIRK algorithm is more efficient than lowering time-step size using a high order loosely-coupled IMEX algorithm. In addition, by using the ESDIRK schemes, gain in computational efficiency relative to Crank-Nicolson is observed for time-accurate solutions (a factor of 1.4 using the fourth order ESDIRK). The computational gain is higher for smaller tolerances.
Runge-Kutta Methods for Linear Ordinary Differential Equations
NASA Technical Reports Server (NTRS)
Zingg, David W.; Chisholm, Todd T.
1997-01-01
Three new Runge-Kutta methods are presented for numerical integration of systems of linear inhomogeneous ordinary differential equations (ODES) with constant coefficients. Such ODEs arise in the numerical solution of the partial differential equations governing linear wave phenomena. The restriction to linear ODEs with constant coefficients reduces the number of conditions which the coefficients of the Runge-Kutta method must satisfy. This freedom is used to develop methods which are more efficient than conventional Runge-Kutta methods. A fourth-order method is presented which uses only two memory locations per dependent variable, while the classical fourth-order Runge-Kutta method uses three. This method is an excellent choice for simulations of linear wave phenomena if memory is a primary concern. In addition, fifth- and sixth-order methods are presented which require five and six stages, respectively, one fewer than their conventional counterparts, and are therefore more efficient. These methods are an excellent option for use with high-order spatial discretizations.
Generalized disks of contractivity for explicit and implicit Runge-Kutta methods
NASA Technical Reports Server (NTRS)
Dahlquist, G.; Jeltsch, R.
1979-01-01
The A-contractivity of Runge-Kutta methods with respect to an inner product norm was investigated thoroughly by Butcher and Burrage (who used the term B-stability). Their theory is extended to contractivity in a region bounded by a circle through the origin. The largest possible circle is calculated for many known explicit Runge-Kutta methods. As a rule it is considerably smaller than the stability region, and in several cases it degenerates to a point. It is shown that an explicit Runge-Kutta method cannot be contractive in any circle of this class if it is more than fourth order accurate.
Numerically optimal Runge-Kutta pairs with interpolants
NASA Astrophysics Data System (ADS)
Verner, J.
2010-03-01
Explicit Runge-Kutta pairs are known to provide efficient solutions to initial value differential equations with inexpensive derivative evaluations. Two criteria for selection are proposed with a view to deriving pairs of all orders 6(5) to 9(8) which minimize computation while achieving a user-specified accuracy. Coefficients of improved pairs, their stability regions and coefficients of appended optimal interpolatory Runge-Kutta formulas are provided on the author's website (www.math.sfu.ca/~jverner). This note reports results of tests on these pairs to illustrate their effectiveness in solving nonstiff initial value problems. These pairs and interpolants may be used for implementation, or else to provide comparison targets for other new types of methods such as explicit general linear methods.
Accurate Monotonicity - Preserving Schemes With Runge-Kutta Time Stepping
NASA Technical Reports Server (NTRS)
Suresh, A.; Huynh, H. T.
1997-01-01
A new class of high-order monotonicity-preserving schemes for the numerical solution of conservation laws is presented. The interface value in these schemes is obtained by limiting a higher-order polynominal reconstruction. The limiting is designed to preserve accuracy near extrema and to work well with Runge-Kutta time stepping. Computational efficiency is enhanced by a simple test that determines whether the limiting procedure is needed. For linear advection in one dimension, these schemes are shown as well as the Euler equations also confirm their high accuracy, good shock resolution, and computational efficiency.
Minimally implicit Runge-Kutta methods for Resistive Relativistic MHD
NASA Astrophysics Data System (ADS)
Aloy, Miguel-Á.; Cordero-Carrión, Isabel
2016-05-01
The Relativistic Resistive Magnetohydrodynamic (RRMHD) equations are a hyperbolic system of partial differential equations used to describe the dynamics of relativistic magnetized fluids with a finite conductivity. Close to the ideal magnetohydrodynamic regime, the source term proportional to the conductivity becomes potentially stiff and cannot be handled with standard explicit time integration methods. We propose a new class of methods to deal with the stiffness fo the system, which we name Minimally Implicit Runge-Kutta methods. These methods avoid the development of numerical instabilities without increasing the computational costs in comparison with explicit methods, need no iterative extra loop in order to recover the primitive (physical) variables, the analytical inversion of the implicit operator is trivial and the several stages can actually be viewed as stages of explicit Runge-Kutta methods with an effective time-step. We test these methods with two different one-dimensional test beds in varied conductivity regimes, and show that our second-order schemes satisfy the theoretical expectations.
On implicit Runge-Kutta methods for parallel computations
NASA Technical Reports Server (NTRS)
Keeling, Stephen L.
1987-01-01
Implicit Runge-Kutta methods which are well-suited for parallel computations are characterized. It is claimed that such methods are first of all, those for which the associated rational approximation to the exponential has distinct poles, and these are called multiply explicit (MIRK) methods. Also, because of the so-called order reduction phenomenon, there is reason to require that these poles be real. Then, it is proved that a necessary condition for a q-stage, real MIRK to be A sub 0-stable with maximal order q + 1 is that q = 1, 2, 3, or 5. Nevertheless, it is shown that for every positive integer q, there exists a q-stage, real MIRK which is I-stable with order q. Finally, some useful examples of algebraically stable MIRKs are given.
Additive Runge-Kutta Schemes for Convection-Diffusion-Reaction Equations
NASA Technical Reports Server (NTRS)
Kennedy, Christopher A.; Carpenter, Mark H.
2001-01-01
Additive Runge-Kutta (ARK) methods are investigated for application to the spatially discretized one-dimensional convection-diffusion-reaction (CDR) equations. First, accuracy, stability, conservation, and dense output are considered for the general case when N different Runge-Kutta methods are grouped into a single composite method. Then, implicit-explicit, N = 2, additive Runge-Kutta ARK2 methods from third- to fifth-order are presented that allow for integration of stiff terms by an L-stable, stiffly-accurate explicit, singly diagonally implicit Runge-Kutta (ESDIRK) method while the nonstiff terms are integrated with a traditional explicit Runge-Kutta method (ERK). Coupling error terms are of equal order to those of the elemental methods. Derived ARK2 methods have vanishing stability functions for very large values of the stiff scaled eigenvalue, z(exp [I]) goes to infinity, and retain high stability efficiency in the absence of stiffness, z(exp [I]) goes to zero. Extrapolation-type stage-value predictors are provided based on dense-output formulae. Optimized methods minimize both leading order ARK2 error terms and Butcher coefficient magnitudes as well as maximize conservation properties. Numerical tests of the new schemes on a CDR problem show negligible stiffness leakage and near classical order convergence rates. However, tests on three simple singular-perturbation problems reveal generally predictable order reduction. Error control is best managed with a PID-controller. While results for the fifth-order method are disappointing, both the new third- and fourth-order methods are at least as efficient as existing ARK2 methods while offering error control and stage-value predictors.
NASA Astrophysics Data System (ADS)
Kalogiratou, Z.; Monovasilis, Th.; Psihoyios, G.; Simos, T. E.
2014-03-01
In this work we review single step methods of the Runge-Kutta type with special properties. Among them are methods specially tuned to integrate problems that exhibit a pronounced oscillatory character and such problems arise often in celestial mechanics and quantum mechanics. Symplectic methods, exponentially and trigonometrically fitted methods, minimum phase-lag and phase-fitted methods are presented. These are Runge-Kutta, Runge-Kutta-Nyström and Partitioned Runge-Kutta methods. The theory of constructing such methods is given as well as several specific methods. In order to present the performance of the methods we have tested 58 methods from all categories. We consider the two dimensional harmonic oscillator, the two body problem, the pendulum problem and the orbital problem studied by Stiefel and Bettis. Also we have tested the methods on the computation of the eigenvalues of the one dimensional time independent Schrödinger equation with the harmonic oscillator, the doubly anharmonic oscillator and the exponential potentials.
Finite volume TVD Runge Kutta scheme for Navier Stokes computations
NASA Astrophysics Data System (ADS)
Bassi, F.; Grasso, F.; Savini, M.
A numerical procedure for the solution of the Navier-Stokes equations for compressible flows is described and demonstrated. In this finite-volume approach, an upwind-biased second-order TVD scheme based on the method of Harten (1983) is employed for the inviscid (Euler) part of the flow; the viscous contribution is obtained by central differencing; and time integration of the resulting system of ODEs is achieved using a Runge-Kutta algorithm. Results are presented graphically for (1) laminar flow in a double-throat nozzle at Re = 1600; (2) turbulent flow on an RAE2822 airfoil at freestream Mach number 0.75, alpha = 2.70, and Re = 6.2 x 10 to the 6th; and (3) turbulent flow in an LS59TG cascade at M(2is) = 1.31, alpha(1) = 30, and Re(1) = 600,000. Good agreement with published experimental data is demonstrated.
Galerkin/Runge-Kutta discretizations for parabolic equations with time-dependent coefficients
NASA Technical Reports Server (NTRS)
Keeling, Stephen L.
1989-01-01
A new class of fully discrete Galerkin/Runge-Kutta methods is constructed and analyzed for linear parabolic initial boundary value problems with time dependent coefficients. Unlike any classical counterpart, this class offers arbitrarily high order convergence while significantly avoiding what has been called order reduction. In support of this claim, error estimates are proved, and computational results are presented. Additionally, since the time stepping equations involve coefficient matrices changing at each time step, a preconditioned iterative technique is used to solve the linear systems only approximately. Nevertheless, the resulting algorithm is shown to preserve the original convergence rate while using only the order of work required by the base scheme applied to a linear parabolic problem with time independent coefficients. Furthermore, it is noted that special Runge-Kutta methods allow computations to be performed in parallel so that the final execution time can be reduced to that of a low order method.
Galerkin/Runge-Kutta discretizations for parabolic equations with time dependent coefficients
NASA Technical Reports Server (NTRS)
Keeling, Stephen L.
1987-01-01
A new class of fully discrete Galerkin/Runge-Kutta methods is constructed and analyzed for linear parabolic initial boundary value problems with time dependent coefficients. Unlike any classical counterpart, this class offers arbitrarily high order convergence while significantly avoiding what has been called order reduction. In support of this claim, error estimates are proved, and computational results are presented. Additionally, since the time stepping equations involve coefficient matrices changing at each time step, a preconditioned iterative technique is used to solve the linear systems only approximately. Nevertheless, the resulting algorithm is shown to preserve the original convergence rate while using only the order of work required by the base scheme applied to a linear parabolic problem with time independent coefficients. Furthermore, it is noted that special Runge-Kutta methods allow computations to be performed in parallel so that the final execution time can be reduced to that of a low order method.
A Runge-Kutta discontinuous finite element method for high speed flows
NASA Technical Reports Server (NTRS)
Bey, Kim S.; Oden, J. T.
1991-01-01
A Runge-Kutta discontinuous finite element method is developed for hyperbolic systems of conservation laws in two space variables. The discontinuous Galerkin spatial approximation to the conservation laws results in a system of ordinary differential equations which are marched in time using Runge-Kutta methods. Numerical results for the two-dimensional Burger's equation show that the method is (p+1)-order accurate in time and space, where p is the degree of the polynomial approximation of the solution within an element and is capable of capturing shocks over a single element without oscillations. Results for this problem also show that the accuracy of the solution in smooth regions is unaffected by the local projection and that the accuracy in smooth regions increases as p increases. Numerical results for the Euler equations show that the method captures shocks without oscillations and with higher resolution than a first-order scheme.
Block method of Runge Kutta type for solving differential algebraic equation
NASA Astrophysics Data System (ADS)
Wen, Khoo Kai; Majid, Zanariah Abdul; Senu, Norazak
2015-10-01
In this paper, a self-starting block method of Runge Kutta type is proposed to solve semi-explicit index-1 differential algebraic equation (DAE). Semi-explicit DAE consists of a system of ordinary differential equations with algebraic constraints. This method will compute the solutions of DAE at two points simultaneously in a block by block steps using constant step size. The DAE is a stiff equation, therefore the Newton iteration is needed during the implementation. Numerical examples are given in order to illustrate the efficiency of the block method when solving the DAE.
A delay differential equation solver based on a continuous Runge-Kutta method with defect control
NASA Astrophysics Data System (ADS)
Enright, W. H.; Hayashi, H.
1997-03-01
We have recently developed a generic approach for solving neutral delay differential equations based on the use of a continuous Runge-Kutta formula with defect control and investigated its convergence properties. In this paper, we describe a method, DDVERK, which implements this approach and justify the strategies and heuristics that have been adopted. In particular we show how the assumptions related to error control, stepsize control, and discontinuity detection (required for convergence) can be efficiently realized for a particular sixth-order numerical method. Summaries of extensive testing are also reported.
A nearly analytic symplectically partitioned Runge-Kutta method for 2-D seismic wave equations
NASA Astrophysics Data System (ADS)
Ma, Xiao; Yang, Dinghui; Liu, Faqi
2011-10-01
In this paper, we develop a new nearly analytic symplectically partitioned Runge-Kutta (NSPRK) method for numerically solving elastic wave equations. In this method, we first transform the elastic wave equations into a Hamiltonian system, and use the nearly analytic discrete operator to approximate the high-order spatial differential operators, and then we employ the partitioned second-order symplectic Runge-Kutta method to numerically solve the resulted semi-discrete Hamiltonian ordinary differential equations (ODEs). We investigate in great detail on the properties of the NSPRK method that includes the stability condition for the P-SV wave in a 2-D homogeneous isotropic medium, the computational efficiency, and the numerical dispersion relation for the 2-D acoustic case. Meanwhile, we apply the NSPRK to simulate the elastic wave propagating in several multilayer models with both strong velocity contrasts and fluctuating interfaces. Both theoretical analysis and numerical results show that the NSPRK can effectively suppress the numerical dispersion resulted from the discretization of the wave equations, and more importantly, it preserves the symplecticity structure for long-time computation. In addition, numerical experiments demonstrate that the NSPRK is effective to combine the split perfectly matched layer boundary conditions to take care of the reflections from the artificial boundaries.
A computer program for determining truncation error coefficients for Runge-Kutta methods
NASA Technical Reports Server (NTRS)
Horn, M. K.
1980-01-01
The basic structure of a program to generate the truncation error coefficients for Runge-Kutta (RK) methods is reformulated to reduce storage requirements significantly and to accommodate variable dimensioning. This FORTRAN program, SUBROUTINE RKEQ, determines truncation error coefficients for RK algorithms for orders 1 through 10 and extends the order of coefficients through 12 with the 11th- and 12th-order terms determined following the patterns used to establish the lower order coefficients. Both subroutines (the original and RKEQ) are also written to treat RK m-fold methods which utilize m known derivatives of f to increase the order of the algorithm. Setting m = 0 gives the classical RK algorithm.
Runge-Kutta time-stepping schemes with TVD central differencing for the water hammer equations
NASA Astrophysics Data System (ADS)
Wahba, E. M.
2006-10-01
In the present study, Runge-Kutta schemes are used to simulate unsteady flow in elastic pipes due to sudden valve closure. The spatial derivatives are discretized using a central difference scheme. Second-order dissipative terms are added in regions of high gradients while they are switched off in smooth flow regions using a total variation diminishing (TVD) switch. The method is applied to both one- and two-dimensional water hammer formulations. Both laminar and turbulent flow cases are simulated. Different turbulence models are tested including the Baldwin-Lomax and Cebeci-Smith models. The results of the present method are in good agreement with analytical results and with experimental data available in the literature. The two-dimensional model is shown to predict more accurately the frictional damping of the pressure transient. Moreover, through order of magnitude and dimensional analysis, a non-dimensional parameter is identified that controls the damping of pressure transients in elastic pipes.
An explicit Runge-Kutta method for turbulent reacting flow calculations
NASA Technical Reports Server (NTRS)
Boretti, A. A.
1989-01-01
The paper presents a numerical method for the solution of the conservation equations governing steady, reacting, turbulent viscous flow in two-dimensional geometries, in both Cartesian and axisymmetric coordinates. These equations are written in Favre-averaged form and closed with a first order model. A two-equation K-epsilon model, where low Reynolds number and compressibility effects are included, and a modified eddy-break up model are used to simulate fluid mechanics turbulence, chemistry and turbulence-combustion interaction. The solution is obtained by using a pseudo-unsteady method with improved perturbation propagation properties. The equations are discretized in space by using a finite volume formulation. An explicit multi-stage dissipative Runge-Kutta algorithm is then used to advance the flow equations in the pseudo-time. The method is applied to the computation of both diffusion and premixed turbulent reacting flows. The computed temperature distributions compare favorably with experimental data.
Rendering log aesthetic curves via Runge-Kutta method
NASA Astrophysics Data System (ADS)
Gobithaasan, R. U.; Meng, T. Y.; Piah, A. R. M.; Miura, K. T.
2014-07-01
Log Aesthetic Curves (LAC) are visually pleasing curves which has been developed using monotonic curvature profile. Hence, it can be easily implemented in product design environment, e.g, Rhino 3D CAD systems. LAC is generally represented in an integral form of its turning angle. Traditionally, Gaussian-Kronrod method has been used to render this curve which consumes less than one second for a given interval. Recently, Incomplete Gamma Function was proposed to represent LAC analytically which decreases the computation time up to 13 times. However, only certain value of shape parameters (denoted as α) which dictates the types of curves generated for LAC, can be used to compute LAC. In this paper, the classical Runge-Kutta (RK4) method is proposed to evaluate LAC numerically to reduce the LAC computation time for arbitrary, α. The preliminary result looks promising where the evaluation time is decreased tremendously. This paper also demonstrates the accuracy control of LAC by reducing the stepsize of RK4. The computation time and the accuracy for various α, are also illustrated in the last section of this paper.
NASA Astrophysics Data System (ADS)
Cavaglieri, Daniele; Bewley, Thomas
2015-04-01
Implicit/explicit (IMEX) Runge-Kutta (RK) schemes are effective for time-marching ODE systems with both stiff and nonstiff terms on the RHS; such schemes implement an (often A-stable or better) implicit RK scheme for the stiff part of the ODE, which is often linear, and, simultaneously, a (more convenient) explicit RK scheme for the nonstiff part of the ODE, which is often nonlinear. Low-storage RK schemes are especially effective for time-marching high-dimensional ODE discretizations of PDE systems on modern (cache-based) computational hardware, in which memory management is often the most significant computational bottleneck. In this paper, we develop and characterize eight new low-storage implicit/explicit RK schemes which have higher accuracy and better stability properties than the only low-storage implicit/explicit RK scheme available previously, the venerable second-order Crank-Nicolson/Runge-Kutta-Wray (CN/RKW3) algorithm that has dominated the DNS/LES literature for the last 25 years, while requiring similar storage (two, three, or four registers of length N) and comparable floating-point operations per timestep.
NASA Astrophysics Data System (ADS)
Diele, F.; Marangi, C.; Ragni, S.
2009-08-01
Direct numerical approximation of a continuous-time infinite horizon control problem, requires to recast the model as a discrete-time, finite-horizon control model. The quality of the optimization results can be heavily degraded if the discretization process does not take into account features of the original model to be preserved. Restricting their attention to optimal growh problems with a steady state, Mercenier and Michel in [1] and [2], studied the conditions to be imposed for ensuring that discrete first-order approximation models have the same steady states as the infinite-horizon continuous-times counterpart. Here we show that Mercenier and Michel scheme is a first order partitioned Runge-Kutta method applied to the state-costate differential system which arises from the Pontryagin maximum principle. The main consequence is that it is possible to consider high order schemes which generalize that algorithm by preserving the steady-growth invariance of the solutions with respect to the discretization process. Numerical examples show the efficiency and accuracy of the proposed methods when applied to the classical Ramsey growth model.
Low-Storage, Explicit Runge-Kutta Schemes for the Compressible Navier-Stokes Equations
NASA Technical Reports Server (NTRS)
Kennedy, Chistopher A.; Carpenter, Mark H.; Lewis, R. Michael
1999-01-01
The derivation of storage explicit Runge-Kutta (ERK) schemes has been performed in the context of integrating the compressible Navier-Stokes equations via direct numerical simulation. Optimization of ERK methods is done across the broad range of properties, such as stability and accuracy efficiency, linear and nonlinear stability, error control reliability, step change stability, and dissipation/dispersion accuracy, subject to varying degrees of memory economization. Following van der Houwen and Wray, 16 ERK pairs are presented using from two to five registers of memory per equation, per grid point and having accuracies from third- to fifth-order. Methods have been assessed using the differential equation testing code DETEST, and with the 1D wave equation. Two of the methods have been applied to the DNS of a compressible jet as well as methane-air and hydrogen-air flames. Derived 3(2) and 4(3) pairs are competitive with existing full-storage methods. Although a substantial efficiency penalty accompanies use of two- and three-register, fifth-order methods, the best contemporary full-storage methods can be pearl), matched while still saving two to three registers of memory.
On the application of runge-kutta methods to transport calculations
Nelson, P.; Jeffery, J.
1988-11-01
Under a definition suitable to the transport equation, it is shown that the (two-stage explicit) Runge-Kutta (RK) methods having order of at least 2, and requiring essentially only one source evaluation per cell, consist of a one-parameter family, plus two additional methods. Two of these, the midpoint corrector and improved Euler methods, are selected for detailed computational comparison with the classical diamond-difference and step characteristic methods. Extensive monodirectional calculations reveal that the RK methods display absolute instability for cell path lengths exceeding 2 mfp, but that they are nearly competitive with the classical methods for small cell widths. It is shown how the two subject RK methods can be augmented by closure approximations, so as to permit their use in source iteration for multiple-direction calculations. The results of such calculations show that for small cell widths, the RK methods again are nearly competitive in accuracy, although the absolute stability requirement can impose a stringent upper bound on the acceptable cell widths; the RK methods interact well with source iteration, even though they do not conserve particles; and the particular closure approximations selected retain the second-order accuracy of the basic underlying methods.
Diagonally Implicit Runge-Kutta Methods for Ordinary Differential Equations. A Review
NASA Technical Reports Server (NTRS)
Kennedy, Christopher A.; Carpenter, Mark H.
2016-01-01
A review of diagonally implicit Runge-Kutta (DIRK) methods applied to rst-order ordinary di erential equations (ODEs) is undertaken. The goal of this review is to summarize the characteristics, assess the potential, and then design several nearly optimal, general purpose, DIRK-type methods. Over 20 important aspects of DIRKtype methods are reviewed. A design study is then conducted on DIRK-type methods having from two to seven implicit stages. From this, 15 schemes are selected for general purpose application. Testing of the 15 chosen methods is done on three singular perturbation problems. Based on the review of method characteristics, these methods focus on having a stage order of two, sti accuracy, L-stability, high quality embedded and dense-output methods, small magnitudes of the algebraic stability matrix eigenvalues, small values of aii, and small or vanishing values of the internal stability function for large eigenvalues of the Jacobian. Among the 15 new methods, ESDIRK4(3)6L[2]SA is recommended as a good default method for solving sti problems at moderate error tolerances.
Implicit - symplectic partitioned (IMSP) Runge-Kutta schemes for predator-prey dynamics
NASA Astrophysics Data System (ADS)
Diele, F.; Marangi, C.; Ragni, S.
2012-09-01
In the study of the effects of habitat fragmentation on biodiversity the role of spatial processes reveals of great interest since both the variation of size of the domains as well as their heterogeneity largely affects the dynamics of species. In order to begin a preliminary study about the effects of habitat fragmentation on wolf - wild boar pair populating the Italian "Alta Murgia" Natura 2000 site, object of interest for FP7 project BIOSOS, (BIOdiversity multi-SOurce Monitoring System: from Space TO Species), spatially explicit models described by reaction-diffusion partial differential equations are considered. Numerical methods based on partitioned Runge-Kutta schemes which use an implicit scheme for the stiff diffusive term and a partitioned symplectic scheme for the reaction function are here proposed. We are motivated by the classical results about Lotka-Volterra model described by ordinary differential equations to which the spatially explicit model reduces for diffusion coefficients tending to zero: for their accurate solution symplectic schemes have to be used for an optimal long run preservation of the dynamics invariant. Moreover, for models based on logistic growth and Holling type II functional predator response we verify the better performance of our schemes when compared with classical implicit-explicit (IMEX) schemes on chaotic dynamics given in literature.
Modified Runge-Kutta methods for solving ODES. M.S. Thesis
NASA Technical Reports Server (NTRS)
Vanvu, T.
1981-01-01
A class of Runge-Kutta formulas is examined which permit the calculation of an accurate solution anywhere in the interval of integration. This is used in a code which seldom has to reject a step; rather it takes a reduced step if the estimated error is too large. The absolute stability implications of this are examined.
A Runge-Kutta discontinuous Galerkin approach to solve reactive flows: The hyperbolic operator
Billet, G.; Ryan, J.
2011-02-20
A Runge-Kutta discontinuous Galerkin method to solve the hyperbolic part of reactive Navier-Stokes equations written in conservation form is presented. Complex thermodynamics laws are taken into account. Particular care has been taken to solve the stiff gaseous interfaces correctly with no restrictive hypothesis. 1D and 2D test cases are presented.
NASA Technical Reports Server (NTRS)
Cockrell, C. R.
1989-01-01
Numerical solutions of the differential equation which describe the electric field within an inhomogeneous layer of permittivity, upon which a perpendicularly-polarized plane wave is incident, are considered. Richmond's method and the Runge-Kutta method are compared for linear and exponential profiles of permittivities. These two approximate solutions are also compared with the exact solutions.
NASA Astrophysics Data System (ADS)
Langer, Stefan
2014-11-01
For unstructured finite volume methods an agglomeration multigrid with an implicit multistage Runge-Kutta method as a smoother is developed for solving the compressible Reynolds averaged Navier-Stokes (RANS) equations. The implicit Runge-Kutta method is interpreted as a preconditioned explicit Runge-Kutta method. The construction of the preconditioner is based on an approximate derivative. The linear systems are solved approximately with a symmetric Gauss-Seidel method. To significantly improve this solution method grid anisotropy is treated within the Gauss-Seidel iteration in such a way that the strong couplings in the linear system are resolved by tridiagonal systems constructed along these directions of strong coupling. The agglomeration strategy is adapted to this procedure by taking into account exactly these anisotropies in such a way that a directional coarsening is applied along these directions of strong coupling. Turbulence effects are included by a Spalart-Allmaras model, and the additional transport-type equation is approximately solved in a loosely coupled manner with the same method. For two-dimensional and three-dimensional numerical examples and a variety of differently generated meshes we show the wide range of applicability of the solution method. Finally, we exploit the GMRES method to determine approximate spectral information of the linearized RANS equations. This approximate spectral information is used to discuss and compare characteristics of multistage Runge-Kutta methods.
NASA Astrophysics Data System (ADS)
Wang, Xiaoqiang; Ju, Lili; Du, Qiang
2016-07-01
The Willmore flow formulated by phase field dynamics based on the elastic bending energy model has been widely used to describe the shape transformation of biological lipid vesicles. In this paper, we develop and investigate some efficient and stable numerical methods for simulating the unconstrained phase field Willmore dynamics and the phase field Willmore dynamics with fixed volume and surface area constraints. The proposed methods can be high-order accurate and are completely explicit in nature, by combining exponential time differencing Runge-Kutta approximations for time integration with spectral discretizations for spatial operators on regular meshes. We also incorporate novel linear operator splitting techniques into the numerical schemes to improve the discrete energy stability. In order to avoid extra numerical instability brought by use of large penalty parameters in solving the constrained phase field Willmore dynamics problem, a modified augmented Lagrange multiplier approach is proposed and adopted. Various numerical experiments are performed to demonstrate accuracy and stability of the proposed methods.
NASA Technical Reports Server (NTRS)
Shih, C. C.
1973-01-01
A theoretical investigation of gas flow inside a multilayer insulation system has been made for the case of the broadside pumping process. A set of simultaneous first-order differential equations for the temperature and pressure of the gas mixture was obtained by considering the diffusion mechanism of the gas molecules through the perforations on the insulation layers. A modified Runge-Kutta method was used for numerical experiment. The numerical stability problem was investigated. It has been shown that when the relaxation time is small compared with the time period over which the gas properties change appreciably, the set of differential equations can be replaced by a set of algebraic equations for solution. Numerical examples were given, and comparisons with experimental data were made.
A weighted Runge-Kutta discontinuous Galerkin method for wavefield modelling
NASA Astrophysics Data System (ADS)
He, Xijun; Yang, Dinghui; Wu, Hao
2015-03-01
In this paper, we propose a weighted Runge-Kutta (RK) discontinuous Galerkin (WRKDG) method for wavefield modelling. For this method, we first transform the seismic wave equations in 2-D heterogeneous anisotropic media into a first-order hyperbolic system, and then combine the discontinuous Galerkin method (DGM) with a weighted RK time discretization. The time discretization is based on an implicit diagonal RK method and an explicit technique, which changes the implicit RK method into an explicit one. In addition, we introduce a weighting factor in the process. Linear and quadratic polynomials for spatial basis functions are typically employed. We investigate the properties of the method in great detail, including the stability criteria and numerical dispersion relations for solving the 2-D acoustic equations. Our analysis indicates that the stability condition for the WRKDG method is more relaxed compared with the classic total variation diminishing (TVD) RK discontinuous Galerkin (RKDG) method, resulting in a 1.7 times superiority for P1 element and is about as efficient as TVD RKDG method for P2 element in computational efficiency. We also demonstrate that the WRKDG method can suppress numerical dispersion more efficiently than the staggered-grid (SG) method on the same grid. The WRKDG method is applied to simulate the wavefields in a large velocity contrast model, a 2-D homogeneous transversely isotropic (TI) model, a fluid-filled fracture model, and a 2-D SEG/EAGE salt dome model. Regular rectangular and irregular triangular elements are used. The numerical results show that the WRKDG method can effectively suppress numerical dispersion and provide accurate information on the wavefield on a coarse mesh. Therefore, the method evidently reduces the scale of the problem and increases computational efficiency. In addition, promising numerical tests show that the WRKDG method combines well with split perfectly matched layer boundary conditions.
Runge-Kutta methods combined with compact difference schemes for the unsteady Euler equations
NASA Technical Reports Server (NTRS)
Yu, Sheng-Tao
1992-01-01
Recent development using compact difference schemes to solve the Navier-Stokes equations show spectral-like accuracy. A study was made of the numerical characteristics of various combinations of the Runge-Kutta (RK) methods and compact difference schemes to calculate the unsteady Euler equations. The accuracy of finite difference schemes is assessed based on the evaluations of dissipative error. The objectives are reducing the numerical damping and, at the same time, preserving numerical stability. While this approach has tremendous success solving steady flows, numerical characteristics of unsteady calculations remain largely unclear. For unsteady flows, in addition to the dissipative errors, phase velocity and harmonic content of the numerical results are of concern. As a result of the discretization procedure, the simulated unsteady flow motions actually propagate in a dispersive numerical medium. Consequently, the dispersion characteristics of the numerical schemes which relate the phase velocity and wave number may greatly impact the numerical accuracy. The aim is to assess the numerical accuracy of the simulated results. To this end, the Fourier analysis is to provide the dispersive correlations of various numerical schemes. First, a detailed investigation of the existing RK methods is carried out. A generalized form of an N-step RK method is derived. With this generalized form, the criteria are derived for the three and four-step RK methods to be third and fourth-order time accurate for the non-linear equations, e.g., flow equations. These criteria are then applied to commonly used RK methods such as Jameson's 3-step and 4-step schemes and Wray's algorithm to identify the accuracy of the methods. For the spatial discretization, compact difference schemes are presented. The schemes are formulated in the operator-type to render themselves suitable for the Fourier analyses. The performance of the numerical methods is shown by numerical examples. These examples
Convergence Acceleration of Runge-Kutta Schemes for Solving the Navier-Stokes Equations
NASA Technical Reports Server (NTRS)
Swanson, Roy C., Jr.; Turkel, Eli; Rossow, C.-C.
2007-01-01
The convergence of a Runge-Kutta (RK) scheme with multigrid is accelerated by preconditioning with a fully implicit operator. With the extended stability of the Runge-Kutta scheme, CFL numbers as high as 1000 can be used. The implicit preconditioner addresses the stiffness in the discrete equations associated with stretched meshes. This RK/implicit scheme is used as a smoother for multigrid. Fourier analysis is applied to determine damping properties. Numerical dissipation operators based on the Roe scheme, a matrix dissipation, and the CUSP scheme are considered in evaluating the RK/implicit scheme. In addition, the effect of the number of RK stages is examined. Both the numerical and computational efficiency of the scheme with the different dissipation operators are discussed. The RK/implicit scheme is used to solve the two-dimensional (2-D) and three-dimensional (3-D) compressible, Reynolds-averaged Navier-Stokes equations. Turbulent flows over an airfoil and wing at subsonic and transonic conditions are computed. The effects of the cell aspect ratio on convergence are investigated for Reynolds numbers between 5:7 x 10(exp 6) and 100 x 10(exp 6). It is demonstrated that the implicit preconditioner can reduce the computational time of a well-tuned standard RK scheme by a factor between four and ten.
NASA Astrophysics Data System (ADS)
Elkina, N. V.; Fedotov, A. M.; Herzing, C.; Ruhl, H.
2014-05-01
The Landau-Lifshitz equation provides an efficient way to account for the effects of radiation reaction without acquiring the nonphysical solutions typical for the Lorentz-Abraham-Dirac equation. We solve the Landau-Lifshitz equation in its covariant four-vector form in order to control both the energy and momentum of radiating particles. Our study reveals that implicit time-symmetric collocation methods of the Runge-Kutta-Nyström type are superior in accuracy and better at maintaining the mass-shell condition than their explicit counterparts. We carry out an extensive study of numerical accuracy by comparing the analytical and numerical solutions of the Landau-Lifshitz equation. Finally, we present the results of the simulation of particle scattering by a focused laser pulse. Due to radiation reaction, particles are less capable of penetrating into the focal region compared to the case where radiation reaction is neglected. Our results are important for designing forthcoming experiments with high intensity laser fields.
An explicit Runge-Kutta method for unsteady rotor/stator interaction
NASA Technical Reports Server (NTRS)
Jorgenson, Philip C. E.; Chima, Rodrick V.
1988-01-01
A quasi-three-dimensional rotor/stator analysis has been developed for blade-to-blade flows in turbomachinery. The analysis solves the unsteady Euler or thin-layer Navier-Stokes equations in a body-fitted coordinate system. It accounts for the effects of rotation, radius change, and stream-surface thickness. The Baldwin-Lomax eddy-viscosity model is used for turbulent flows. The equations are integrated in time using a four-stage Runge-Kutta scheme with a constant timestep. Results are shown for the first stage of the Space Shuttle Main Engine high pressure fuel turbopump. Euler and Navier-Stokes results are compared on the scaled single- and multi-passage machine. The method is relatively fast and the quasi-three-dimensional formulation is applicable to a wide range of turbomachinery geometries.
Runge-Kutta model-based nonlinear observer for synchronization and control of chaotic systems.
Beyhan, Selami
2013-07-01
This paper proposes a novel nonlinear gradient-based observer for synchronization and observer-based control of chaotic systems. The model is based on a Runge-Kutta model of the chaotic system where the evolution of the states or parameters is derived based on the error-square minimization. The stability and convergence conditions of observer and control methods are analyzed using a Lyapunov stability approach. In numerical simulations, the proposed observer and well-known sliding-mode observer are compared for the synchronization of a Lü chaotic system and observer-based stabilization of a Chen chaotic system. The noisy case for synchronization and parameter uncertainty case for stabilization are also considered for both observer-based methods.
NASA Technical Reports Server (NTRS)
Kanevsky, Alex
2004-01-01
My goal is to develop and implement efficient, accurate, and robust Implicit-Explicit Runge-Kutta (IMEX RK) methods [9] for overcoming geometry-induced stiffness with applications to computational electromagnetics (CEM), computational fluid dynamics (CFD) and computational aeroacoustics (CAA). IMEX algorithms solve the non-stiff portions of the domain using explicit methods, and isolate and solve the more expensive stiff portions using implicit methods. Current algorithms in CEM can only simulate purely harmonic (up to lOGHz plane wave) EM scattering by fighter aircraft, which are assumed to be pure metallic shells, and cannot handle the inclusion of coatings, penetration into and radiation out of the aircraft. Efficient MEX RK methods could potentially increase current CEM capabilities by 1-2 orders of magnitude, allowing scientists and engineers to attack more challenging and realistic problems.
The 4th order GISS model of the global atmosphere
NASA Technical Reports Server (NTRS)
Kalnay-Rivas, E.; Bayliss, A.; Storch, J.
1977-01-01
The new GISS 4th order model of the global atmosphere is described. It is based on 4th order quadratically conservative differences with the periodic application of a 16th order filter on the sea level pressure and potential temperature equations, a combination which is approximately enstrophy conserving. Several short range forecasts indicate a significant improvement over 2nd order forecasts with the same resolution (approximately 400 km). However the 4th order forecasts are somewhat inferior to 2nd order forecasts with double resolution. This is probably due to the presence of short waves in the range between 1000 km and 2000 km, which are computed more accurately by the 2nd order high resolution model. An operation count of the schemes indicates that with similar code optimization, the 4th order model will require approximately the same amount of computer time as the 2nd order model with the same resolution. It is estimated that the 4th order model with a grid size of 200 km provides enough accuracy to make horizontal truncation errors negligible over a period of a week for all synoptic scales (waves longer than 1000 km).
NASA Astrophysics Data System (ADS)
Yang, Hongli; Zeng, Xianyang; Wu, Xinyuan; Ru, Zhengliang
2014-11-01
In the study of extended Runge-Kutta-Nyström (abbr. ERKN) methods for the integration of multi-frequency oscillatory systems, a quite complicated set of algebraic conditions arises which must be satisfied for a method to achieve some specified order. A theory of tri-colored tree was proposed by Yang et al. (2009), for achieving the order conditions of ERKN methods which are designed specially for multi-frequency and multidimensional perturbed oscillators. The tri-colored tree theory for the order conditions in that paper is useful, but not completely satisfactory due to the existence of redundant trees. In this paper, a simplified tri-colored theory and the order conditions for ERKN integrators are developed by constructing a set of simplified special extended Nyström trees (abbr. SSENT) and defining some real-valued mappings on it. In order to simplify the tri-colored tree theory, two special mappings, the extended elementary differential and the sign mapping for a tree are investigated in detail. This leads to a novel Nyström-tree theory for the order conditions for ERKN methods without any redundant trees, which simplifies the tri-colored theory.
Cui, Hengfei; Wang, Desheng; Wan, Min; Zhang, Jun-Mei; Zhao, Xiaodan; Tan, Ru San; Huang, Weimin; Xiong, Wei; Duan, Yuping; Zhou, Jiayin; Luo, Tong; Kassab, Ghassan S; Zhong, Liang
2016-06-01
The CT angiography (CTA) is a clinically indicated test for the assessment of coronary luminal stenosis that requires centerline extractions. There is currently no centerline extraction algorithm that is automatic, real-time and very accurate. Therefore, we sought to (i) develop a hybrid approach by incorporating fast marching and Runge-Kutta based methods for the extraction of coronary artery centerlines from CTA; (ii) evaluate the accuracy of the present method compared to Van's method by using ground truth centerline as a reference; (iii) evaluate the coronary lumen area of our centerline method in comparison with the intravascular ultrasound (IVUS) as the standard of reference. The proposed method was found to be more computationally efficient, and performed better than the Van's method in terms of overlap measures (i.e., OV: [Formula: see text] vs. [Formula: see text]; OF: [Formula: see text] vs. [Formula: see text]; and OT: [Formula: see text] vs. [Formula: see text], all [Formula: see text]). In comparison with IVUS derived coronary lumen area, the proposed approach was more accurate than the Van's method. This hybrid approach by incorporating fast marching and Runge-Kutta based methods could offer fast and accurate extraction of centerline as well as the lumen area. This method may garner wider clinical potential as a real-time coronary stenosis assessment tool. PMID:27140197
Analysis of numerical stability and amplification matrices: Fourth-order Runge-Kutta methods
NASA Technical Reports Server (NTRS)
Kennedy, E. W.
1979-01-01
Amplification matrices, numerical kernels, stable, and exponentially stable numerical solutions are examined. The various techniques involved in these concepts are applied to certain systems that have Jordan forms, which are nondiagonal, with particular interest in the case of imaginary or zero eigenvalues.
Xu, Zhiliang; Chen, Xu-Yan; Liu, Yingjie
2014-01-01
We present a new formulation of the Runge-Kutta discontinuous Galerkin (RKDG) method [9, 8, 7, 6] for solving conservation Laws with increased CFL numbers. The new formulation requires the computed RKDG solution in a cell to satisfy additional conservation constraint in adjacent cells and does not increase the complexity or change the compactness of the RKDG method. Numerical computations for solving one-dimensional and two-dimensional scalar and systems of nonlinear hyperbolic conservation laws are performed with approximate solutions represented by piecewise quadratic and cubic polynomials, respectively. The hierarchical reconstruction [17, 33] is applied as a limiter to eliminate spurious oscillations in discontinuous solutions. From both numerical experiments and the analytic estimate of the CFL number of the newly formulated method, we find that: 1) this new formulation improves the CFL number over the original RKDG formulation by at least three times or more and thus reduces the overall computational cost; and 2) the new formulation essentially does not compromise the resolution of the numerical solutions of shock wave problems compared with ones computed by the RKDG method. PMID:25414520
Xu, Zhiliang; Chen, Xu-Yan; Liu, Yingjie
2014-12-01
We present a new formulation of the Runge-Kutta discontinuous Galerkin (RKDG) method [9, 8, 7, 6] for solving conservation Laws with increased CFL numbers. The new formulation requires the computed RKDG solution in a cell to satisfy additional conservation constraint in adjacent cells and does not increase the complexity or change the compactness of the RKDG method. Numerical computations for solving one-dimensional and two-dimensional scalar and systems of nonlinear hyperbolic conservation laws are performed with approximate solutions represented by piecewise quadratic and cubic polynomials, respectively. The hierarchical reconstruction [17, 33] is applied as a limiter to eliminate spurious oscillations in discontinuous solutions. From both numerical experiments and the analytic estimate of the CFL number of the newly formulated method, we find that: 1) this new formulation improves the CFL number over the original RKDG formulation by at least three times or more and thus reduces the overall computational cost; and 2) the new formulation essentially does not compromise the resolution of the numerical solutions of shock wave problems compared with ones computed by the RKDG method.
Chen, Zhaoxia; Li, Juan; Zhang, Ruqiang; You, Xiong
2015-01-01
Oscillation is one of the most important phenomena in the chemical reaction systems in living cells. The general purpose simulation algorithms fail to take into account this special character and produce unsatisfying results. In order to enhance the accuracy of the integrator, the second-order derivative is incorporated in the scheme. The oscillatory feature of the solution is captured by the integrators with an exponential fitting property. Three practical exponentially fitted TDRK (EFTDRK) methods are derived. To test the effectiveness of the new EFTDRK methods, the two-gene system with cross-regulation and the circadian oscillation of the period protein in Drosophila are simulated. Each EFTDRK method has the best fitting frequency which minimizes the global error. The numerical results show that the new EFTDRK methods are more accurate and more efficient than their prototype TDRK methods or RK methods of the same order and the traditional exponentially fitted RK method in the literature. PMID:26633991
NASA Technical Reports Server (NTRS)
Abarbanel, Saul; Gottlieb, David; Carpenter, Mark H.
1994-01-01
It has been previously shown that the temporal integration of hyperbolic partial differential equations (PDE's) may, because of boundary conditions, lead to deterioration of accuracy of the solution. A procedure for removal of this error in the linear case has been established previously. In the present paper we consider hyperbolic (PDE's) (linear and non-linear) whose boundary treatment is done via the SAT-procedure. A methodology is present for recovery of the full order of accuracy, and has been applied to the case of a 4th order explicit finite difference scheme.
High-order parabolic beam approximation for aero-optics
White, Michael D.
2010-08-01
The parabolic beam equations are solved using high-order compact differences for the Laplacians and Runge-Kutta integration along the beam path. The solution method is verified by comparison to analytical solutions for apertured beams and both constant and complex index of refraction. An adaptive 4th-order Runge-Kutta using an embedded 2nd-order method is presented that has demonstrated itself to be very robust. For apertured beams, the results show that the method fails to capture near aperture effects due to a violation of the paraxial approximation in that region. Initial results indicate that the problem appears to be correctable by successive approximations. A preliminary assessment of the effect of turbulent scales is undertaken using high-order Lagrangian interpolation. The results show that while high fidelity methods are necessary to accurately capture the large scale flow structure, the method may not require the same level of fidelity in sampling the density for the index of refraction. The solution is used to calculate a phase difference that is directly compared with that commonly calculated via the optical path difference. Propagation through a supersonic boundary layer shows that for longer wavelengths, the traditional method to calculate the optical path is less accurate than for shorter wavelengths. While unlikely to supplant more traditional methods for most aero-optics applications, the current method can be used to give a quantitative assessment of the other methods as well as being amenable to the addition of more physics.
Multi-Dimensional Asymptotically Stable 4th Order Accurate Schemes for the Diffusion Equation
NASA Technical Reports Server (NTRS)
Abarbanel, Saul; Ditkowski, Adi
1996-01-01
An algorithm is presented which solves the multi-dimensional diffusion equation on co mplex shapes to 4th-order accuracy and is asymptotically stable in time. This bounded-error result is achieved by constructing, on a rectangular grid, a differentiation matrix whose symmetric part is negative definite. The differentiation matrix accounts for the Dirichlet boundary condition by imposing penalty like terms. Numerical examples in 2-D show that the method is effective even where standard schemes, stable by traditional definitions fail.
Computational aspects of the nonlinear normal mode initialization of the GLAS 4th order GCM
NASA Technical Reports Server (NTRS)
Navon, I. M.; Bloom, S. C.; Takacs, L.
1984-01-01
Using the normal modes of the GLAS 4th Order Model, a Machenhauer nonlinear normal mode initialization (NLNMI) was carried out for the external vertical mode using the GLAS 4th Order shallow water equations model for an equivalent depth corresponding to that associated with the external vertical mode. A simple procedure was devised which was directed at identifying computational modes by following the rate of increase of BAL sub M, the partial (with respect to the zonal wavenumber m) sum of squares of the time change of the normal mode coefficients (for fixed vertical mode index) varying over the latitude index L of symmetric or antisymmetric gravity waves. A working algorithm is presented which speeds up the convergence of the iterative Machenhauer NLNMI. A 24 h integration using the NLNMI state was carried out using both Matsuno and leap-frog time-integration schemes; these runs were then compared to a 24 h integration starting from a non-initialized state. The maximal impact of the nonlinear normal mode initialization was found to occur 6-10 hours after the initial time.
High-Order Residual-Distribution Hyperbolic Advection-Diffusion Schemes: 3rd-, 4th-, and 6th-Order
NASA Technical Reports Server (NTRS)
Mazaheri, Alireza R.; Nishikawa, Hiroaki
2014-01-01
In this paper, spatially high-order Residual-Distribution (RD) schemes using the first-order hyperbolic system method are proposed for general time-dependent advection-diffusion problems. The corresponding second-order time-dependent hyperbolic advection- diffusion scheme was first introduced in [NASA/TM-2014-218175, 2014], where rapid convergences over each physical time step, with typically less than five Newton iterations, were shown. In that method, the time-dependent hyperbolic advection-diffusion system (linear and nonlinear) was discretized by the second-order upwind RD scheme in a unified manner, and the system of implicit-residual-equations was solved efficiently by Newton's method over every physical time step. In this paper, two techniques for the source term discretization are proposed; 1) reformulation of the source terms with their divergence forms, and 2) correction to the trapezoidal rule for the source term discretization. Third-, fourth, and sixth-order RD schemes are then proposed with the above techniques that, relative to the second-order RD scheme, only cost the evaluation of either the first derivative or both the first and the second derivatives of the source terms. A special fourth-order RD scheme is also proposed that is even less computationally expensive than the third-order RD schemes. The second-order Jacobian formulation was used for all the proposed high-order schemes. The numerical results are then presented for both steady and time-dependent linear and nonlinear advection-diffusion problems. It is shown that these newly developed high-order RD schemes are remarkably efficient and capable of producing the solutions and the gradients to the same order of accuracy of the proposed RD schemes with rapid convergence over each physical time step, typically less than ten Newton iterations.
1:1 Ground-track resonance in a uniformly rotating 4th degree and order gravitational field
NASA Astrophysics Data System (ADS)
Feng, Jinglang; Noomen, Ron; Hou, Xiyun; Visser, Pieter; Yuan, Jianping
2016-09-01
Using a gravitational field truncated at the 4th degree and order, the 1:1 ground-track resonance is studied. To address the main properties of this resonance, a 1-degree of freedom (1-DOF) system is firstly studied. Equilibrium points (EPs), stability and resonance width are obtained. Different from previous studies, the inclusion of non-spherical terms higher than degree and order 2 introduces new phenomena. For a further study about this resonance, a 2-DOF model which includes a main resonance term (the 1-DOF system) and a perturbing resonance term is studied. With the aid of Poincaré sections, the generation of chaos in the phase space is studied in detail by addressing the overlap process of these two resonances with arbitrary combinations of eccentricity (e) and inclination (i). Retrograde orbits, near circular orbits and near polar orbits are found to have better stability against the perturbation of the second resonance. The situations of complete chaos are estimated in the e-i plane. By applying the maximum Lyapunov Characteristic Exponent (LCE), chaos is characterized quantitatively and similar conclusions can be achieved. This study is applied to three asteroids 1996 HW1, Vesta and Betulia, but the conclusions are not restricted to them.
A Very High Order, Adaptable MESA Implementation for Aeroacoustic Computations
NASA Technical Reports Server (NTRS)
Dydson, Roger W.; Goodrich, John W.
2000-01-01
Since computational efficiency and wave resolution scale with accuracy, the ideal would be infinitely high accuracy for problems with widely varying wavelength scales. Currently, many of the computational aeroacoustics methods are limited to 4th order accurate Runge-Kutta methods in time which limits their resolution and efficiency. However, a new procedure for implementing the Modified Expansion Solution Approximation (MESA) schemes, based upon Hermitian divided differences, is presented which extends the effective accuracy of the MESA schemes to 57th order in space and time when using 128 bit floating point precision. This new approach has the advantages of reducing round-off error, being easy to program. and is more computationally efficient when compared to previous approaches. Its accuracy is limited only by the floating point hardware. The advantages of this new approach are demonstrated by solving the linearized Euler equations in an open bi-periodic domain. A 500th order MESA scheme can now be created in seconds, making these schemes ideally suited for the next generation of high performance 256-bit (double quadruple) or higher precision computers. This ease of creation makes it possible to adapt the algorithm to the mesh in time instead of its converse: this is ideal for resolving varying wavelength scales which occur in noise generation simulations. And finally, the sources of round-off error which effect the very high order methods are examined and remedies provided that effectively increase the accuracy of the MESA schemes while using current computer technology.
Comparison of rhodomine-WT and sodium chloride tracer transport in a 4th order arctic river
NASA Astrophysics Data System (ADS)
Smull, E. M.; Wlostowski, A. N.; Gooseff, M. N.; Bowden, W. B.; Wollheim, W. M.
2012-12-01
Conservative tracers are useful for tracking a parcel of water through a river reach and understanding tracer transport phenomena (i.e. advection, dispersion, and transient storage). Rhodomine- WT (RWT) and sodium chloride (NaCl) are two popular stream tracers. NaCl is considered to be conservative and relatively inexpensive, yet it cannot be detected at very low concentrations. On the other hand, RWT can be detected at very low concentrations (<0.1 ppb), but it is known to photo-degrade and sorb to organic materials. Previous work has compared these tracers with small-scale laboratory analyses and field experiments on small headwater streams. The limitations and advantages to each of these tracers, as applied to large river slug injections, are not clearly understood. This work seeks to answer the following questions: 1) Does RWT improve the tracer window of detection (time of tracer arrival to time of tracer non-detection), compared to NaCl? 2) Are there differences in the late-time tailing behavior of each tracer? More specifically, can we compare RWT and NaCl breakthrough curve tail shapes to understand processes contributing to late time solute transport (transient storage or sorption-desorption)? During the summer of 2012, combined slug additions of RWT and NaCl were injected into a 1.5-kilometer reach on the Kuparuk River, a 4th order tundra river underlain by continuous permafrost located on Alaska's North Slope. Fluorescence and electrical conductivity were continuously logged at the upstream and downstream ends of the reach. Preliminary results show that the window of detection is expanded when using RWT under both high and low flow conditions by 0.2 times the advective transport timescale. Tail shapes are more similar under higher discharge conditions and dissimilar under lower discharge conditions. For example, using an exponential regression model (c(t) = eat) to quantify tail shapes, at Q = 500 l/s the exponential coefficient ratio, aRWT:aNaCl, is 0
A third-order multistep time discretization for a Chebyshev tau spectral method
NASA Astrophysics Data System (ADS)
Vreman, A. W.; Kuerten, J. G. M.
2016-01-01
A time discretization scheme based on the third-order backward difference formula has been embedded into a Chebyshev tau spectral method for the Navier-Stokes equations. The time discretization is a variant of the second-order backward scheme proposed by Krasnov et al. (2008) [3]. High-resolution direct numerical simulations of turbulent incompressible channel flow have been performed to compare the backward scheme to the Runge-Kutta scheme proposed by Spalart et al. (1991) [2]. It is shown that the Runge-Kutta scheme leads to a poor convergence of some third-order spatial derivatives in the direct vicinity of the wall, derivatives that represent the diffusion of wall-tangential vorticity. The convergence at the wall is shown to be significantly improved if the backward scheme is applied.
Higher-Order Compact Schemes for Numerical Simulation of Incompressible Flows
NASA Technical Reports Server (NTRS)
Wilson, Robert V.; Demuren, Ayodeji O.; Carpenter, Mark
1998-01-01
A higher order accurate numerical procedure has been developed for solving incompressible Navier-Stokes equations for 2D or 3D fluid flow problems. It is based on low-storage Runge-Kutta schemes for temporal discretization and fourth and sixth order compact finite-difference schemes for spatial discretization. The particular difficulty of satisfying the divergence-free velocity field required in incompressible fluid flow is resolved by solving a Poisson equation for pressure. It is demonstrated that for consistent global accuracy, it is necessary to employ the same order of accuracy in the discretization of the Poisson equation. Special care is also required to achieve the formal temporal accuracy of the Runge-Kutta schemes. The accuracy of the present procedure is demonstrated by application to several pertinent benchmark problems.
On the Total Variation of High-Order Semi-Discrete Central Schemes for Conservation Laws
NASA Technical Reports Server (NTRS)
Bryson, Steve; Levy, Doron
2004-01-01
We discuss a new fifth-order, semi-discrete, central-upwind scheme for solving one-dimensional systems of conservation laws. This scheme combines a fifth-order WENO reconstruction, a semi-discrete central-upwind numerical flux, and a strong stability preserving Runge-Kutta method. We test our method with various examples, and give particular attention to the evolution of the total variation of the approximations.
ERIC Educational Resources Information Center
Baydo-Reed, Katie
2010-01-01
Following the bombing of Pearl Harbor on Dec. 7, 1941, U.S. officials issued a series of proclamations that violated the civil and human rights of the vast majority of Japanese Americans in the United States--ostensibly to protect the nation from further Japanese aggression. The proclamations culminated in Executive Order 9066, which gave the…
Linear 3 and 5-step methods using Taylor series expansion for solving special 3rd order ODEs
NASA Astrophysics Data System (ADS)
Rajabi, Marzieh; Ismail, Fudziah; Senu, Norazak
2016-06-01
Some new linear 3 and 5-step methods for solving special third order ordinary differential equations directly are constructed using Taylor's series expansion. A set of test problems are solved using the new method and the results are compared when the problem is reduced to a system of first order ordinary differential equations and then using the existing Runge-Kutta method. The numerical results have clearly shown the advantage and competency of the new methods.
NASA Astrophysics Data System (ADS)
Wang, Jia; Su, Lin; Wei, Xiaomin; Zheng, Ran; Hu, Yann
2016-09-01
This paper presents an ASIC readout circuit development, which aims to achieve low noise. In order to compensate the leakage current and improve gain, a dual-stage CSA has been utilized. A 4th-order high-linearity shaper is proposed to obtain a Semi-Gaussian wave and further decrease the noise induced by the leakage current. The ASIC has been designed and fabricated in a standard commercial 2P4M 0.35 μm CMOS process. Die area of one channel is about 1190 μm×147 μm. The input charge range is 1.8 fC. The peaking time can be adjusted from 1 μs to 3 μs. Measured ENC is about 55e- (rms) at input capacitor of 0 F. The gain is 271 mV/fC at the peaking time of 1 μs.
NASA Technical Reports Server (NTRS)
Navon, I. M.; Bloom, S.; Takacs, L. L.
1985-01-01
An attempt was made to use the GLAS global 4th order shallow water equations to perform a Machenhauer nonlinear normal mode initialization (NLNMI) for the external vertical mode. A new algorithm was defined for identifying and filtering out computational modes which affect the convergence of the Machenhauer iterative procedure. The computational modes and zonal waves were linearly initialized and gravitational modes were nonlinearly initialized. The Machenhauer NLNMI was insensitive to the absence of high zonal wave numbers. The effects of the Machenhauer scheme were evaluated by performing 24 hr integrations with nondissipative and dissipative explicit time integration models. The NLNMI was found to be inferior to the Rasch (1984) pseudo-secant technique for obtaining convergence when the time scales of nonlinear forcing were much smaller than the time scales expected from the natural frequency of the mode.
NASA Astrophysics Data System (ADS)
O'Daniel, S. J.; Amerson, B. E.; Lambert, M. B.
2014-12-01
Persistent societal interest in improving water quality and recovering imperiled, native, aquatic species has expanded the scope of stream restoration to include the hyporheic zone as a focus. Despite the lack of detailed studies, hyporheic restoration is often invoked as a means to achieve multiple objectives including moderation of water temperature, delay of seasonal flows and increasing the localized volume of floodplain water. We present interim results from an ongoing case study that monitors the changes as a result of stream restoration of the hyporheic zone of a 4th order, alluvial floodplain in northeast Oregon, USA, Meacham Creek. Active and passive restoration of 2.5 km of Meacham Creek has altered the creek from a single-threaded, incised and bedrock-dominated channel to a perched, alluvial channel that seasonally exchanges overbank flows with the surrounding floodplain. Our results suggest that the stream restoration effort on Meacham Creek has increased the volume of annual hyporheic storage and created a more diverse distribution of flowpath lengths within the restoration site. Furthermore, our monitoring indicates that hyporheic process response to stream restoration, analogous to other geomorphic processes, conforms to a systematic hierarchy where nested flow paths range in length and residence time from meters and hours at the habitat scale to tens of meters and months at the floodplain scale. We assert that scale-explicit and measurement-focused restoration planning has a greater likelihood of meeting the stated objectives and result in improved water quality and encourage recovery of many native aquatic species.
Contractivity-preserving explicit Hermite-Obrechkoff ODE solver of order 13
NASA Astrophysics Data System (ADS)
Nguyen-Ba, Truong; Desjardins, Steven J.; Sharp, Philip W.; Vaillancourt, Rémi
2013-12-01
A new optimal, explicit, Hermite-Obrechkoff method of order 13, denoted by HO(13), that is contractivity-preserving (CP) and has nonnegative coefficients is constructed for solving nonstiff first-order initial value problems. Based on the CP conditions, the new 9-derivative HO(13) has maximum order 13. The new method usually requires significantly fewer function evaluations and significantly less CPU time than the Taylor method of order 13 and the Runge-Kutta method DP(8,7)13M to achieve the same global error when solving standard -body problems.
Computations of Flow Over the Hump Model Using Higher-Order Method With Turbulence Modeling
NASA Technical Reports Server (NTRS)
Balakumar, P.
2007-01-01
The flow over the two-dimensional hump model is computed by solving the RANS equations with kappa-omega (SST) model. The governing equations, the flow equations and the turbulent equations, are solved using the 5th order accurate weighted essentially non-oscillatory (WENO) scheme for space discretization and using explicit third order total-variation-diminishing (TVD) Runge-Kutta scheme for time integration. The WENO and the TVD methods and the formulas are explained in [1] and the application of ENO method to N-S equations is given in [2]. The solution method implemented in this computation is described in detail in [3].
A fifth order implicit method for the numerical solution of differential-algebraic equations
NASA Astrophysics Data System (ADS)
Skvortsov, L. M.
2015-06-01
An implicit two-step Runge-Kutta method of fifth order is proposed for the numerical solution of differential and differential-algebraic equations. The location of nodes in this method makes it possible to estimate the values of higher derivatives at the initial and terminal points of an integration step. Consequently, the proposed method can be regarded as a finite-difference analog of the Obrechkoff method. Numerical results, some of which are presented in this paper, show that our method preserves its order while solving stiff equations and equations of indices two and three. This is the main advantage of the proposed method as compared with the available ones.
Liang, Xiao; Khaliq, Abdul Q. M.; Xing, Yulong
2015-01-23
In this paper, we study a local discontinuous Galerkin method combined with fourth order exponential time differencing Runge-Kutta time discretization and a fourth order conservative method for solving the nonlinear Schrödinger equations. Based on different choices of numerical fluxes, we propose both energy-conserving and energy-dissipative local discontinuous Galerkin methods, and have proven the error estimates for the semi-discrete methods applied to linear Schrödinger equation. The numerical methods are proven to be highly efficient and stable for long-range soliton computations. Finally, extensive numerical examples are provided to illustrate the accuracy, efficiency and reliability of the proposed methods.
A second-order accurate immersed boundary-lattice Boltzmann method for particle-laden flows
NASA Astrophysics Data System (ADS)
Zhou, Qiang; Fan, Liang-Shih
2014-07-01
A new immersed boundary-lattice Boltzmann method (IB-LBM) is presented for fully resolved simulations of incompressible viscous flows laden with rigid particles. The immersed boundary method (IBM) recently developed by Breugem (2012) [19] is adopted in the present method, development including the retraction technique, the multi-direct forcing method and the direct account of the inertia of the fluid contained within the particles. The present IB-LBM is, however, formulated with further improvement with the implementation of the high-order Runge-Kutta schemes in the coupled fluid-particle interaction. The major challenge to implement high-order Runge-Kutta schemes in the LBM is that the flow information such as density and velocity cannot be directly obtained at a fractional time step from the LBM since the LBM only provides the flow information at an integer time step. This challenge can be, however, overcome as given in the present IB-LBM by extrapolating the flow field around particles from the known flow field at the previous integer time step. The newly calculated fluid-particle interactions from the previous fractional time steps of the current integer time step are also accounted for in the extrapolation. The IB-LBM with high-order Runge-Kutta schemes developed in this study is validated by several benchmark applications. It is demonstrated, for the first time, that the IB-LBM has the capacity to resolve the translational and rotational motion of particles with the second-order accuracy. The optimal retraction distances for spheres and tubes that help the method achieve the second-order accuracy are found to be around 0.30 and -0.47 times of the lattice spacing, respectively. Simulations of the Stokes flow through a simple cubic lattice of rotational spheres indicate that the lift force produced by the Magnus effect can be very significant in view of the magnitude of the drag force when the practical rotating speed of the spheres is encountered. This finding
McCorquodale, Peter; Ullrich, Paul; Johansen, Hans; Colella, Phillip
2015-09-04
We present a high-order finite-volume approach for solving the shallow-water equations on the sphere, using multiblock grids on the cubed-sphere. This approach combines a Runge--Kutta time discretization with a fourth-order accurate spatial discretization, and includes adaptive mesh refinement and refinement in time. Results of tests show fourth-order convergence for the shallow-water equations as well as for advection in a highly deformational flow. Hierarchical adaptive mesh refinement allows solution error to be achieved that is comparable to that obtained with uniform resolution of the most refined level of the hierarchy, but with many fewer operations.
Guzik, S; McCorquodale, P; Colella, P
2011-12-16
A fourth-order accurate finite-volume method is presented for solving time-dependent hyperbolic systems of conservation laws on mapped grids that are adaptively refined in space and time. Novel considerations for formulating the semi-discrete system of equations in computational space combined with detailed mechanisms for accommodating the adapting grids ensure that conservation is maintained and that the divergence of a constant vector field is always zero (freestream-preservation property). Advancement in time is achieved with a fourth-order Runge-Kutta method.
The 4th Thermodynamic Principle?
Montero Garcia, Jose de la Luz; Novoa Blanco, Jesus Francisco
2007-04-28
It should be emphasized that the 4th Principle above formulated is a thermodynamic principle and, at the same time, is mechanical-quantum and relativist, as it should inevitably be and its absence has been one of main the theoretical limitations of the physical theory until today.We show that the theoretical discovery of Dimensional Primitive Octet of Matter, the 4th Thermodynamic Principle, the Quantum Hexet of Matter, the Global Hexagonal Subsystem of Fundamental Constants of Energy and the Measurement or Connected Global Scale or Universal Existential Interval of the Matter is that it is possible to be arrived at a global formulation of the four 'forces' or fundamental interactions of nature. The Einstein's golden dream is possible.
Seismic Waves, 4th order accurate
2013-08-16
SW4 is a program for simulating seismic wave propagation on parallel computers. SW4 colves the seismic wave equations in Cartesian corrdinates. It is therefore appropriate for regional simulations, where the curvature of the earth can be neglected. SW4 implements a free surface boundary condition on a realistic topography, absorbing super-grid conditions on the far-field boundaries, and a kinematic source model consisting of point force and/or point moment tensor source terms. SW4 supports a fully 3-D heterogeneous material model that can be specified in several formats. SW4 can output synthetic seismograms in an ASCII test format, or in the SAC finary format. It can also present simulation information as GMT scripts, whixh can be used to create annotated maps. Furthermore, SW4 can output the solution as well as the material model along 2-D grid planes.
Seismic Waves, 4th order accurate
2013-08-16
SW4 is a program for simulating seismic wave propagation on parallel computers. SW4 colves the seismic wave equations in Cartesian corrdinates. It is therefore appropriate for regional simulations, where the curvature of the earth can be neglected. SW4 implements a free surface boundary condition on a realistic topography, absorbing super-grid conditions on the far-field boundaries, and a kinematic source model consisting of point force and/or point moment tensor source terms. SW4 supports a fully 3-Dmore » heterogeneous material model that can be specified in several formats. SW4 can output synthetic seismograms in an ASCII test format, or in the SAC finary format. It can also present simulation information as GMT scripts, whixh can be used to create annotated maps. Furthermore, SW4 can output the solution as well as the material model along 2-D grid planes.« less
A high-order finite-volume method for hyperbolic conservation laws on locally-refined grids
McCorquodale, Peter; Colella, Phillip
2011-01-28
We present a fourth-order accurate finite-volume method for solving time-dependent hyperbolic systems of conservation laws on Cartesian grids with multiple levels of refinement. The underlying method is a generalization of that in [5] to nonlinear systems, and is based on using fourth-order accurate quadratures for computing fluxes on faces, combined with fourth-order accurate Runge?Kutta discretization in time. To interpolate boundary conditions at refinement boundaries, we interpolate in time in a manner consistent with the individual stages of the Runge-Kutta method, and interpolate in space by solving a least-squares problem over a neighborhood of each target cell for the coefficients of a cubic polynomial. The method also uses a variation on the extremum-preserving limiter in [8], as well as slope flattening and a fourth-order accurate artificial viscosity for strong shocks. We show that the resulting method is fourth-order accurate for smooth solutions, and is robust in the presence of complex combinations of shocks and smooth flows.
Sanders, Ross H.; Gonjo, Tomohiro; McCabe, Carla B.
2015-01-01
The purpose of this study was to explore the reliability of estimating three-dimensional (3D) linear kinematics and kinetics of a swimmer derived from digitized video and to assess the effect of framing rate and smoothing window size. A stroke cycle of two high-level front crawl swimmers and one high level backstroke swimmer was recorded by four underwater and two above water video cameras. One of the front crawl swimmers was recorded and digitized at 50 Hz with a window for smoothing by 4th order Butterworth digital filter extending 10 frames beyond the start and finish of the stroke cycle, while the other front crawl and backstroke swimmer were recorded and digitized at 25 Hz with the window extending five frames beyond the start and finish of the stroke cycle. Each camera view of the stroke cycle was digitized five times yielding five independent 3D data sets from which whole body centre of mass (CM) component velocities and accelerations were derived together with wrist and ankle linear velocities. Coefficients of reliability ranging from r = 0.942 to r = 0.999 indicated that both methods are sufficiently reliable to identify real differences in net force production during the pulls of the right and left hands. Reliability of digitizing was better for front crawl when digitizing at 50Hz with 10 frames extension than at 25 Hz with 5 frames extension (p < 0.01) and better for backstroke than front crawl (p < 0.01). However, despite the extension and reflection of data, errors were larger in the first 15% of the stroke cycle than the period between 15 and 85% of the stroke cycle for CM velocity and acceleration and for foot speed (p < 0.01). Key points An inverse dynamics based on 3D position data digitized from multiple camera views above and below the water surface is sufficiently reliable to yield insights regarding force production in swimming additional to those of other approaches. The ability to link the force profiles to swimming actions and technique is
Sanders, Ross H; Gonjo, Tomohiro; McCabe, Carla B
2015-06-01
The purpose of this study was to explore the reliability of estimating three-dimensional (3D) linear kinematics and kinetics of a swimmer derived from digitized video and to assess the effect of framing rate and smoothing window size. A stroke cycle of two high-level front crawl swimmers and one high level backstroke swimmer was recorded by four underwater and two above water video cameras. One of the front crawl swimmers was recorded and digitized at 50 Hz with a window for smoothing by 4(th) order Butterworth digital filter extending 10 frames beyond the start and finish of the stroke cycle, while the other front crawl and backstroke swimmer were recorded and digitized at 25 Hz with the window extending five frames beyond the start and finish of the stroke cycle. Each camera view of the stroke cycle was digitized five times yielding five independent 3D data sets from which whole body centre of mass (CM) component velocities and accelerations were derived together with wrist and ankle linear velocities. Coefficients of reliability ranging from r = 0.942 to r = 0.999 indicated that both methods are sufficiently reliable to identify real differences in net force production during the pulls of the right and left hands. Reliability of digitizing was better for front crawl when digitizing at 50Hz with 10 frames extension than at 25 Hz with 5 frames extension (p < 0.01) and better for backstroke than front crawl (p < 0.01). However, despite the extension and reflection of data, errors were larger in the first 15% of the stroke cycle than the period between 15 and 85% of the stroke cycle for CM velocity and acceleration and for foot speed (p < 0.01). Key pointsAn inverse dynamics based on 3D position data digitized from multiple camera views above and below the water surface is sufficiently reliable to yield insights regarding force production in swimming additional to those of other approaches.The ability to link the force profiles to swimming actions and technique is
ERIC Educational Resources Information Center
Anderson, Mike
2011-01-01
Fourth grade is a pivotal year, in which students commonly face increased academic demands. According to Anderson, teachers can help students make a smooth transition to 4th grade by introducing these new challenges in ways that are in line with 4th graders' common developmental characteristics: incredible energy and emotion, industriousness and…
17. 4th floor roof, view south, 4th and 5th floor ...
17. 4th floor roof, view south, 4th and 5th floor setback to left and atrium structure to right - Sheffield Farms Milk Plant, 1075 Webster Avenue (southwest corner of 166th Street), Bronx, Bronx County, NY
Second-Order Accurate Projective Integrators for Multiscale Problems
Lee, S L; Gear, C W
2005-05-27
We introduce new projective versions of second-order accurate Runge-Kutta and Adams-Bashforth methods, and demonstrate their use as outer integrators in solving stiff differential systems. An important outcome is that the new outer integrators, when combined with an inner telescopic projective integrator, can result in fully explicit methods with adaptive outer step size selection and solution accuracy comparable to those obtained by implicit integrators. If the stiff differential equations are not directly available, our formulations and stability analysis are general enough to allow the combined outer-inner projective integrators to be applied to black-box legacy codes or perform a coarse-grained time integration of microscopic systems to evolve macroscopic behavior, for example.
Finite-volume application of high-order ENO schemes to two-dimensional boundary-value problems
NASA Technical Reports Server (NTRS)
Casper, Jay
1991-01-01
Finite-volume applications of high-order accurate ENO schemes to two-dimensional boundary-value problems are studied. These schemes achieve high-order spatial accuracy, in smooth regions, by a piecewise polynomial approximation of the solution from cell averages. In addition, this spatial operation involves an adaptive stencil algorithm in order to avoid the oscillatory behavior that is associated with interpolation across steep gradients. High-order TVD Runge-Kutta methods are employed for time integration, thus making these schemes best suited for unsteady problems. Fifth- and sixth-order accurate applications are validated through a grid refinement study involving the solutions of scalar hyperbolic equations. A previously proposed extension for the Euler equations of gas dynamics is tested, including its application to solutions of boundary-value problems involving solid walls and curvilinear coordinates.
High-Order Implicit-Explicit Multi-Block Time-stepping Method for Hyperbolic PDEs
NASA Technical Reports Server (NTRS)
Nielsen, Tanner B.; Carpenter, Mark H.; Fisher, Travis C.; Frankel, Steven H.
2014-01-01
This work seeks to explore and improve the current time-stepping schemes used in computational fluid dynamics (CFD) in order to reduce overall computational time. A high-order scheme has been developed using a combination of implicit and explicit (IMEX) time-stepping Runge-Kutta (RK) schemes which increases numerical stability with respect to the time step size, resulting in decreased computational time. The IMEX scheme alone does not yield the desired increase in numerical stability, but when used in conjunction with an overlapping partitioned (multi-block) domain significant increase in stability is observed. To show this, the Overlapping-Partition IMEX (OP IMEX) scheme is applied to both one-dimensional (1D) and two-dimensional (2D) problems, the nonlinear viscous Burger's equation and 2D advection equation, respectively. The method uses two different summation by parts (SBP) derivative approximations, second-order and fourth-order accurate. The Dirichlet boundary conditions are imposed using the Simultaneous Approximation Term (SAT) penalty method. The 6-stage additive Runge-Kutta IMEX time integration schemes are fourth-order accurate in time. An increase in numerical stability 65 times greater than the fully explicit scheme is demonstrated to be achievable with the OP IMEX method applied to 1D Burger's equation. Results from the 2D, purely convective, advection equation show stability increases on the order of 10 times the explicit scheme using the OP IMEX method. Also, the domain partitioning method in this work shows potential for breaking the computational domain into manageable sizes such that implicit solutions for full three-dimensional CFD simulations can be computed using direct solving methods rather than the standard iterative methods currently used.
NASA Technical Reports Server (NTRS)
Fatemi, Emad; Jerome, Joseph; Osher, Stanley
1989-01-01
A micron n+ - n - n+ silicon diode is simulated via the hydrodynamic model for carrier transport. The numerical algorithms employed are for the non-steady case, and a limiting process is used to reach steady state. The simulation employs shock capturing algorithms, and indeed shocks, or very rapid transition regimes, are observed in the transient case for the coupled system, consisting of the potential equation and the conservation equations describing charge, momentum, and energy transfer for the electron carriers. These algorithms, termed essentially non-oscillatory, were successfully applied in other contexts to model the flow in gas dynamics, magnetohydrodynamics, and other physical situations involving the conservation laws in fluid mechanics. The method here is first order in time, but the use of small time steps allows for good accuracy. Runge-Kutta methods allow one to achieve higher accuracy in time if desired. The spatial accuracy is of high order in regions of smoothness.
166. GENERAL VIEW DOWN 4TH AVENUE. VIEW NORTHEAST DOWN 4TH ...
166. GENERAL VIEW DOWN 4TH AVENUE. VIEW NORTHEAST DOWN 4TH AVE. FROM BUILDING 44 SHOWING, FROM LEFT TO RIGHT, BUILDING 46, 48, 55, AND 50 (PART OF ENLISTED BARRACKS COMPLEX), AND BUILDINGS 17, 16, 484, 483, 374, AND 375 (IN THE WAREHOUSE COMPLEX). - Quonset Point Naval Air Station, Roger Williams Way, North Kingstown, Washington County, RI
NASA Astrophysics Data System (ADS)
Shi, Fengyan; Kirby, James T.; Harris, Jeffrey C.; Geiman, Joseph D.; Grilli, Stephan T.
We present a high-order adaptive time-stepping TVD solver for the fully nonlinear Boussinesq model of Chen (2006), extended to include moving reference level as in Kennedy et al. (2001). The equations are reorganized in order to facilitate high-order Runge-Kutta time-stepping and a TVD type scheme with a Riemann solver. Wave breaking is modeled by locally switching to the nonlinear shallow water equations when the Froude number exceeds a certain threshold. The moving shoreline boundary condition is implemented using the wetting-drying algorithm with the adjusted wave speed of the Riemann solver. The code is parallelized using the Message Passing Interface (MPI) with non-blocking communication. Model validations show good performance in modeling wave shoaling, breaking, wave runup and wave-averaged nearshore circulation.
Cobb, J.W.
1995-02-01
There is an increasing need for more accurate numerical methods for large-scale nonlinear magneto-fluid turbulence calculations. These methods should not only increase the current state of the art in terms of accuracy, but should also continue to optimize other desired properties such as simplicity, minimized computation, minimized memory requirements, and robust stability. This includes the ability to stably solve stiff problems with long time-steps. This work discusses a general methodology for deriving higher-order numerical methods. It also discusses how the selection of various choices can affect the desired properties. The explicit discussion focuses on third-order Runge-Kutta methods, including general solutions and five examples. The study investigates the linear numerical analysis of these methods, including their accuracy, general stability, and stiff stability. Additional appendices discuss linear multistep methods, discuss directions for further work, and exhibit numerical analysis results for some other commonly used lower-order methods.
NASA Astrophysics Data System (ADS)
Campoamor-Stursberg, R.; Rodríguez, M. A.; Winternitz, P.
2016-01-01
Ordinary differential equations (ODEs) and ordinary difference systems (OΔSs) invariant under the actions of the Lie groups {{SL}}x(2),{{SL}}y(2) and {{SL}}x(2)× {{SL}}y(2) of projective transformations of the independent variables x and dependent variables y are constructed. The ODEs are continuous limits of the OΔSs, or conversely, the OΔSs are invariant discretizations of the ODEs. The invariant OΔSs are used to calculate numerical solutions of the invariant ODEs of order up to five. The solutions of the invariant numerical schemes are compared to numerical solutions obtained by standard Runge-Kutta methods and to exact solutions, when available. The invariant method performs at least as well as standard ones and much better in the vicinity of singularities of solutions.
NASA Astrophysics Data System (ADS)
Balan, Aravind; May, Georg; Schöberl, Joachim
2012-03-01
Numerical schemes using piecewise polynomial approximation are very popular for high order discretization of conservation laws. While the most widely used numerical scheme under this paradigm appears to be the Discontinuous Galerkin method, the Spectral Difference scheme has often been found attractive as well, because of its simplicity of formulation and implementation. However, recently it has been shown that the scheme is not linearly stable on triangles. In this paper we present an alternate formulation of the scheme, featuring a new flux interpolation technique using Raviart-Thomas spaces, which proves stable under a similar linear analysis in which the standard scheme failed. We demonstrate viability of the concept by showing linear stability both in the semi-discrete sense and for time stepping schemes of the SSP Runge-Kutta type. Furthermore, we present convergence studies, as well as case studies in compressible flow simulation using the Euler equations.
Kids & Family Reading Report™. 4th Edition
ERIC Educational Resources Information Center
Scholastic Inc., 2013
2013-01-01
This report presents the 4th Edition of Scholastic's biannual study of children's and parents' attitudes and behaviors about reading. Much has changed since the first "Kids & Family Reading Report" was issued in 2006, but literacy remains the critical skill needed for school success. Today's children are growing up in a world full of…
NASA Astrophysics Data System (ADS)
JavanNezhad, R.; Meshkatee, A. H.; Ghader, S.; Ahmadi-Givi, F.
2016-09-01
This study is devoted to application of the fourth-order compact MacCormack scheme to spatial differencing of the conservative form of two-dimensional and non-hydrostatic equation of a dry atmosphere. To advance the solution in time a four-stage Runge-Kutta method is used. To perform the simulations, two test cases including evolution of a warm bubble and a cold bubble in a neutral atmosphere with open and rigid boundaries are employed. In addition, the second-order MacCormack and the standard fourth-order compact MacCormack schemes are used to perform the simulations. Qualitative and quantitative assessment of the numerical results for different test cases exhibit the superiority of the fourth-order compact MacCormack scheme on the second-order method.
NASA Astrophysics Data System (ADS)
Li, G. Q.; Zhu, Z. H.
2015-12-01
Dynamic modeling of tethered spacecraft with the consideration of elasticity of tether is prone to the numerical instability and error accumulation over long-term numerical integration. This paper addresses the challenges by proposing a globally stable numerical approach with the nodal position finite element method (NPFEM) and the implicit, symplectic, 2-stage and 4th order Gaussian-Legendre Runge-Kutta time integration. The NPFEM eliminates the numerical error accumulation by using the position instead of displacement of tether as the state variable, while the symplectic integration enforces the energy and momentum conservation of the discretized finite element model to ensure the global stability of numerical solution. The effectiveness and robustness of the proposed approach is assessed by an elastic pendulum problem, whose dynamic response resembles that of tethered spacecraft, in comparison with the commonly used time integrators such as the classical 4th order Runge-Kutta schemes and other families of non-symplectic Runge-Kutta schemes. Numerical results show that the proposed approach is accurate and the energy of the corresponding numerical model is conservative over the long-term numerical integration. Finally, the proposed approach is applied to the dynamic modeling of deorbiting process of tethered spacecraft over a long period.
NASA Technical Reports Server (NTRS)
Shu, Chi-Wang
2004-01-01
This project is about the investigation of the development of the discontinuous Galerkin finite element methods, for general geometry and triangulations, for solving convection dominated problems, with applications to aeroacoustics. Other related issues in high order WENO finite difference and finite volume methods have also been investigated. methods are two classes of high order, high resolution methods suitable for convection dominated simulations with possible discontinuous or sharp gradient solutions. In [18], we first review these two classes of methods, pointing out their similarities and differences in algorithm formulation, theoretical properties, implementation issues, applicability, and relative advantages. We then present some quantitative comparisons of the third order finite volume WENO methods and discontinuous Galerkin methods for a series of test problems to assess their relative merits in accuracy and CPU timing. In [3], we review the development of the Runge-Kutta discontinuous Galerkin (RKDG) methods for non-linear convection-dominated problems. These robust and accurate methods have made their way into the main stream of computational fluid dynamics and are quickly finding use in a wide variety of applications. They combine a special class of Runge-Kutta time discretizations, that allows the method to be non-linearly stable regardless of its accuracy, with a finite element space discretization by discontinuous approximations, that incorporates the ideas of numerical fluxes and slope limiters coined during the remarkable development of the high-resolution finite difference and finite volume schemes. The resulting RKDG methods are stable, high-order accurate, and highly parallelizable schemes that can easily handle complicated geometries and boundary conditions. We review the theoretical and algorithmic aspects of these methods and show several applications including nonlinear conservation laws, the compressible and incompressible Navier
NASA Astrophysics Data System (ADS)
Mei, Lijie; Wu, Xinyuan
2016-10-01
In general, extended Runge-Kutta-Nyström (ERKN) methods are more effective than traditional Runge-Kutta-Nyström (RKN) methods in dealing with oscillatory Hamiltonian systems. However, the theoretical analysis for ERKN methods, such as the order conditions, the symplectic conditions and the symmetric conditions, becomes much more complicated than that for RKN methods. Therefore, it is a bottleneck to construct high-order ERKN methods efficiently. In this paper, we first establish the ERKN group Ω for ERKN methods and the RKN group G for RKN methods, respectively. We then rigorously show that ERKN methods are a natural extension of RKN methods, that is, there exists an epimorphism η of the ERKN group Ω onto the RKN group G. This epimorphism gives a global insight into the structure of the ERKN group by the analysis of its kernel and the corresponding RKN group G. Meanwhile, we establish a particular mapping φ of G into Ω so that each image element is an ideal representative element of the congruence class in Ω. Furthermore, an elementary theoretical analysis shows that this map φ can preserve many structure-preserving properties, such as the order, the symmetry and the symplecticity. From the epimorphism η together with its section φ, we may gain knowledge about the structure of the ERKN group Ω via the RKN group G. In light of the theoretical analysis of this paper, we obtain high-order structure-preserving ERKN methods in an effective way for solving oscillatory Hamiltonian systems. Numerical experiments are carried out and the results are very promising, which strongly support our theoretical analysis presented in this paper.
Fourth order difference methods for hyperbolic IBVP's
NASA Technical Reports Server (NTRS)
Gustafsson, Bertil; Olsson, Pelle
1994-01-01
Fourth order difference approximations of initial-boundary value problems for hyperbolic partial differential equations are considered. We use the method of lines approach with both explicit and compact implicit difference operators in space. The explicit operator satisfies an energy estimate leading to strict stability. For the implicit operator we develop boundary conditions and give a complete proof of strong stability using the Laplace transform technique. We also present numerical experiments for the linear advection equation and Burgers' equation with discontinuities in the solution or in its derivative. The first equation is used for modeling contact discontinuities in fluid dynamics, the second one for modeling shocks and rarefaction waves. The time discretization is done with a third order Runge-Kutta TVD method. For solutions with discontinuities in the solution itself we add a filter based on second order viscosity. In case of the non-linear Burger's equation we use a flux splitting technique that results in an energy estimate for certain different approximations, in which case also an entropy condition is fulfilled. In particular we shall demonstrate that the unsplit conservative form produces a non-physical shock instead of the physically correct rarefaction wave. In the numerical experiments we compare our fourth order methods with a standard second order one and with a third order TVD-method. The results show that the fourth order methods are the only ones that give good results for all the considered test problems.
NASA Astrophysics Data System (ADS)
Seny, Bruno; Lambrechts, Jonathan; Toulorge, Thomas; Legat, Vincent; Remacle, Jean-François
2014-01-01
Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by their stability limits. Indeed, the multi-scale nature of some physical processes combined with highly unstructured meshes can lead some elements to impose a severely small stable time step for a global problem. Multirate methods offer a way to increase the global efficiency by gathering grid cells in appropriate groups under local stability conditions. These methods are well suited to the discontinuous Galerkin framework. The parallelization of the multirate strategy is challenging because grid cells have different workloads. The computational cost is different for each sub-time step depending on the elements involved and a classical partitioning strategy is not adequate any more. In this paper, we propose a solution that makes use of multi-constraint mesh partitioning. It tends to minimize the inter-processor communications, while ensuring that the workload is almost equally shared by every computer core at every stage of the algorithm. Particular attention is given to the simplicity of the parallel multirate algorithm while minimizing computational and communication overheads. Our implementation makes use of the MeTiS library for mesh partitioning and the Message Passing Interface for inter-processor communication. Performance analyses for two and three-dimensional practical applications confirm that multirate methods preserve important computational advantages of explicit methods up to a significant number of processors.
4th Generation ECR Ion Sources
Lyneis, Claude M.; Leitner, D.; Todd, D.S.; Sabbi, G.; Prestemon, S.; Caspi, S.; Ferracin, P.
2008-12-01
The concepts and technical challenges related to developing a 4th generation ECR ion source with an RF frequency greater than 40 GHz and magnetic confinement fields greater than twice Becr will be explored in this paper. Based on the semi-empirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current 3rd generation ECR ion sources, which operate at RF frequencies between 20 and 30 GHz. While the 3rd generation ECR ion sources use NbTi superconducting solenoid and sextupole coils, the new sources will need to use different superconducting materials such as Nb3Sn to reach the required magnetic confinement, which scales linearly with RF frequency. Additional technical challenges include increased bremsstrahlung production, which may increase faster than the plasma density, bremsstrahlung heating of the cold mass and the availability of high power continuous wave microwave sources at these frequencies. With each generation of ECR ion sources, there are new challenges to be mastered, but the potential for higher performance and reduced cost of the associated accelerator continue to make this a promising avenue for development.
Fourth-Order Difference Methods for Hyperbolic IBVPs
NASA Astrophysics Data System (ADS)
Gustafsson, Bertil; Olsson, Pelle
1995-03-01
In this paper we consider fourth-order difference approximations of initial-boundary value problems for hyperbolic partial differential equations. We use the method of lines approach with both explicit and compact implicit difference operators in space. The explicit operator satisfies an energy estimate leading to strict stability. For the implicit operator we develop boundary conditions and give a complete proof of strong stability using the Laplace transform technique. We also present numerical experiments for the linear advection equation and Burgers' equation with discontinuities in the solution or in its derivative. The first equation is used for modeling contact discontinuities in fluid dynamics; the second one is used for modeling shocks and rarefaction waves. The time discretization is done with a third-order Runge-Kutta TVD method. For solutions with discontinuities in the solution itself we add a filter based on second-order viscosity. In case of the non-linear Burgers' equation we use a flux splitting technique that results in an energy estimate for certain difference approximations, in which case also an entropy condition is fulfilled. In particular we shall demonstrate that the unsplit conservative form produces a non-physical shock instead of the physically correct rarefaction wave. In the numerical experiments we compare our fourth-order methods with a standard second-order one and with a third-order TVD method. The results show that the fourth-order methods are the only ones that give good results for all the considered test problems.
A neuro approach to solve fuzzy Riccati differential equations
Shahrir, Mohammad Shazri; Kumaresan, N. Kamali, M. Z. M.; Ratnavelu, Kurunathan
2015-10-22
There are many applications of optimal control theory especially in the area of control systems in engineering. In this paper, fuzzy quadratic Riccati differential equation is estimated using neural networks (NN). Previous works have shown reliable results using Runge-Kutta 4th order (RK4). The solution can be achieved by solving the 1st Order Non-linear Differential Equation (ODE) that is found commonly in Riccati differential equation. Research has shown improved results relatively to the RK4 method. It can be said that NN approach shows promising results with the advantage of continuous estimation and improved accuracy that can be produced over RK4.
NASA Astrophysics Data System (ADS)
Balac, Stéphane; Fernandez, Arnaud
2016-02-01
The computer program SPIP is aimed at solving the Generalized Non-Linear Schrödinger equation (GNLSE), involved in optics e.g. in the modelling of light-wave propagation in an optical fibre, by the Interaction Picture method, a new efficient alternative method to the Symmetric Split-Step method. In the SPIP program a dedicated costless adaptive step-size control based on the use of a 4th order embedded Runge-Kutta method is implemented in order to speed up the resolution.
A neuro approach to solve fuzzy Riccati differential equations
NASA Astrophysics Data System (ADS)
Shahrir, Mohammad Shazri; Kumaresan, N.; Kamali, M. Z. M.; Ratnavelu, Kurunathan
2015-10-01
There are many applications of optimal control theory especially in the area of control systems in engineering. In this paper, fuzzy quadratic Riccati differential equation is estimated using neural networks (NN). Previous works have shown reliable results using Runge-Kutta 4th order (RK4). The solution can be achieved by solving the 1st Order Non-linear Differential Equation (ODE) that is found commonly in Riccati differential equation. Research has shown improved results relatively to the RK4 method. It can be said that NN approach shows promising results with the advantage of continuous estimation and improved accuracy that can be produced over RK4.
Compact high order schemes for the Euler equations
NASA Technical Reports Server (NTRS)
Abarbanel, Saul; Kumar, Ajay
1988-01-01
An implicit approximate factorization (AF) algorithm is constructed which has the following characteistics. In 2-D: The scheme is unconditionally stable, has a 3 x 3 stencil and at steady state has a fourth order spatial accuracy. The temporal evolution is time accurate either to first or second order through choice of parameter. In 3-D: The scheme has almost the same properties as in 2-D except that it is now only conditionally stable, with the stability condition (the CFL number) being dependent on the cell aspect ratios, delta y/delta x and delta z/delta x. The stencil is still compact and fourth order accuracy at steady state is maintained. Numerical experiments on a 2-D shock-reflection problem show the expected improvement over lower order schemes, not only in accuracy (measured by the L sub 2 error) but also in the dispersion. It is also shown how the same technique is immediately extendable to Runge-Kutta type schemes resulting in improved stability in addition to the enhanced accuracy.
NASA Astrophysics Data System (ADS)
Li Chun Fong, Lena C. M.; Lach, Grzegorz; Le Roy, Robert J.; Dattani, Nikesh S.
2015-06-01
The 13.81(8)s half-life of the halo nucleonic atom 11Be is orders of magnitude longer than those for any other halo nucleonic atom known, and makes Be-based diatomics the most promising candidates for the formation of the first halo nucleonic molecules. However, the 4e^- species LiH and BeH^+ are some of the first molecules for which the highest accuracy ab initio methods are not accessible, so empirical potential energy functions will be important for making predictions and for benchmarking how ab initio calculations break down at this transition from 3e^- to 4e^-. BeH^+ is also very light, and has one of the most extensive data sets involving a tritium isotopologue, making it a very useful benchmark for studying Born-Oppenheimer breakdown. We therefore seek to determine an empirical analytic potential energy function for BeH^+ that has as much precision as possible. To this end, all available spectroscopic data for all stable isotopologues of BeH^+ are analyzed in a standard direct-potential-fit procedure that uses least-squares fits to optimize the parameters defining an analytic potential. The ``Morse/Long-range'' (MLR) model used for the potential energy function incorporates the inverse-power long-range tail required by theory, and the calculation of the leading long-range coefficients C_4, C_6, C_7, and C_8 include non-adiabatic terms, and up to 4th order QED corrections. As a by-product, we have calculated some fundamental properties of 1e^- systems with unprecedented precision, such as the dipole, quadrupole, octupole, non-adiabatic, and mixed higher order polarizabilities of hydrogen, deuterium, and tritium. We provide good first estimates for the transition energies for the halo nucleonic species 11BeH^+ and 14BeH^+.
Analysis of High Order Difference Methods for Multiscale Complex Compressible Flows
NASA Technical Reports Server (NTRS)
Sjoegreen, Bjoern; Yee, H. C.; Tang, Harry (Technical Monitor)
2002-01-01
Accurate numerical simulations of complex multiscale compressible viscous flows, especially high speed turbulence combustion and acoustics, demand high order schemes with adaptive numerical dissipation controls. Standard high resolution shock-capturing methods are too dissipative to capture the small scales and/or long-time wave propagations without extreme grid refinements and small time steps. An integrated approach for the control of numerical dissipation in high order schemes with incremental studies was initiated. Here we further refine the analysis on, and improve the understanding of the adaptive numerical dissipation control strategy. Basically, the development of these schemes focuses on high order nondissipative schemes and takes advantage of the progress that has been made for the last 30 years in numerical methods for conservation laws, such as techniques for imposing boundary conditions, techniques for stability at shock waves, and techniques for stable and accurate long-time integration. We concentrate on high order centered spatial discretizations and a fourth-order Runge-Kutta temporal discretizations as the base scheme. Near the bound-aries, the base scheme has stable boundary difference operators. To further enhance stability, the split form of the inviscid flux derivatives is frequently used for smooth flow problems. To enhance nonlinear stability, linear high order numerical dissipations are employed away from discontinuities, and nonlinear filters are employed after each time step in order to suppress spurious oscillations near discontinuities to minimize the smearing of turbulent fluctuations. Although these schemes are built from many components, each of which is well-known, it is not entirely obvious how the different components be best connected. For example, the nonlinear filter could instead have been built into the spatial discretization, so that it would have been activated at each stage in the Runge-Kutta time stepping. We could think
Mathematical modeling of intrinsic Josephson junctions with capacitive and inductive couplings
NASA Astrophysics Data System (ADS)
Rahmonov, I. R.; Shukrinov, Yu M.; Zemlyanaya, E. V.; Sarhadov, I.; Andreeva, O.
2012-11-01
We investigate the current voltage characteristics (CVC) of intrinsic Josephson junctions (IJJ) with two types of couplings between junctions: capacitive and inductive. The IJJ model is described by a system of coupled sine-Gordon equations which is solved numerically by the 4th order Runge-Kutta method. The method of numerical simulation and numerical results are presented. The magnetic field distribution is calculated as the function of coordinate and time at different values of the bias current. The influence of model parameters on the CVC is studied. The behavior of the IJJ in dependence on coupling parameters is discussed.
Improving Social Interaction among 4th Grade Students through Social Skills Instruction.
ERIC Educational Resources Information Center
Dunleavy, Shannon; Karwowski, Sandra; Shudes-Eitel, Jennifer
This action research project implemented a program for improving social skills in order to establish positive interaction among 4th grade students at a northern Chicago suburban school. Social skills deficiency was documented through behavior checklists and referrals, teacher observations and student reflection. Teachers reported that low incomes,…
An almost symmetric Strang splitting scheme for the construction of high order composition methods.
Einkemmer, Lukas; Ostermann, Alexander
2014-12-01
In this paper we consider splitting methods for nonlinear ordinary differential equations in which one of the (partial) flows that results from the splitting procedure cannot be computed exactly. Instead, we insert a well-chosen state [Formula: see text] into the corresponding nonlinearity [Formula: see text], which results in a linear term [Formula: see text] whose exact flow can be determined efficiently. Therefore, in the spirit of splitting methods, it is still possible for the numerical simulation to satisfy certain properties of the exact flow. However, Strang splitting is no longer symmetric (even though it is still a second order method) and thus high order composition methods are not easily attainable. We will show that an iterated Strang splitting scheme can be constructed which yields a method that is symmetric up to a given order. This method can then be used to attain high order composition schemes. We will illustrate our theoretical results, up to order six, by conducting numerical experiments for a charged particle in an inhomogeneous electric field, a post-Newtonian computation in celestial mechanics, and a nonlinear population model and show that the methods constructed yield superior efficiency as compared to Strang splitting. For the first example we also perform a comparison with the standard fourth order Runge-Kutta methods and find significant gains in efficiency as well better conservation properties. PMID:25473146
An almost symmetric Strang splitting scheme for the construction of high order composition methods.
Einkemmer, Lukas; Ostermann, Alexander
2014-12-01
In this paper we consider splitting methods for nonlinear ordinary differential equations in which one of the (partial) flows that results from the splitting procedure cannot be computed exactly. Instead, we insert a well-chosen state [Formula: see text] into the corresponding nonlinearity [Formula: see text], which results in a linear term [Formula: see text] whose exact flow can be determined efficiently. Therefore, in the spirit of splitting methods, it is still possible for the numerical simulation to satisfy certain properties of the exact flow. However, Strang splitting is no longer symmetric (even though it is still a second order method) and thus high order composition methods are not easily attainable. We will show that an iterated Strang splitting scheme can be constructed which yields a method that is symmetric up to a given order. This method can then be used to attain high order composition schemes. We will illustrate our theoretical results, up to order six, by conducting numerical experiments for a charged particle in an inhomogeneous electric field, a post-Newtonian computation in celestial mechanics, and a nonlinear population model and show that the methods constructed yield superior efficiency as compared to Strang splitting. For the first example we also perform a comparison with the standard fourth order Runge-Kutta methods and find significant gains in efficiency as well better conservation properties.
Toward a consistent framework for high order mesh refinement schemes in numerical relativity
NASA Astrophysics Data System (ADS)
Mongwane, Bishop
2015-05-01
It has now become customary in the field of numerical relativity to couple high order finite difference schemes to mesh refinement algorithms. To this end, different modifications to the standard Berger-Oliger adaptive mesh refinement algorithm have been proposed. In this work we present a fourth order stable mesh refinement scheme with sub-cycling in time for numerical relativity. We do not use buffer zones to deal with refinement boundaries but explicitly specify boundary data for refined grids. We argue that the incompatibility of the standard mesh refinement algorithm with higher order Runge Kutta methods is a manifestation of order reduction phenomena, caused by inconsistent application of boundary data in the refined grids. Our scheme also addresses the problem of spurious reflections that are generated when propagating waves cross mesh refinement boundaries. We introduce a transition zone on refined levels within which the phase velocity of propagating modes is allowed to decelerate in order to smoothly match the phase velocity of coarser grids. We apply the method to test problems involving propagating waves and show a significant reduction in spurious reflections.
A Fourth Order Difference Scheme for the Maxwell Equations on Yee Grid
Fathy, Aly E; Wilson, Joshua L
2008-09-01
The Maxwell equations are solved by a long-stencil fourth order finite difference method over a Yee grid, in which different physical variables are located at staggered mesh points. A careful treatment of the numerical values near the boundary is introduced, which in turn leads to a 'symmetric image' formula at the 'ghost' grid points. Such a symmetric formula assures the stability of the boundary extrapolation. In turn, the fourth order discrete curl operator for the electric and magnetic vectors gives a complete set of eigenvalues in the purely imaginary axis. To advance the dynamic equations, the four-stage Runge-Kutta method is utilized, which results in a full fourth order accuracy in both time and space. A stability constraint for the time step is formulated at both the theoretical and numerical levels, using an argument of stability domain. An accuracy check is presented to verify the fourth order precision, using a comparison between exact solution and numerical solutions at a fixed final time. In addition, some numerical simulations of a loss-less rectangular cavity are also carried out and the frequency is measured precisely.
A second order residual based predictor-corrector approach for time dependent pollutant transport
NASA Astrophysics Data System (ADS)
Pavan, S.; Hervouet, J.-M.; Ricchiuto, M.; Ata, R.
2016-08-01
We present a second order residual distribution scheme for scalar transport problems in shallow water flows. The scheme, suitable for the unsteady cases, is obtained adapting to the shallow water context the explicit Runge-Kutta schemes for scalar equations [1]. The resulting scheme is decoupled from the hydrodynamics yet the continuity equation has to be considered in order to respect some important numerical properties at discrete level. Beyond the classical characteristics of the residual formulation presented in [1,2], we introduce the possibility to iterate the corrector step in order to improve the accuracy of the scheme. Another novelty is that the scheme is based on a precise monotonicity condition which guarantees the respect of the maximum principle. We thus end up with a scheme which is mass conservative, second order accurate and monotone. These properties are checked in the numerical tests, where the proposed approach is also compared to some finite volume schemes on unstructured grids. The results obtained show the interest in adopting the predictor-corrector scheme for pollutant transport applications, where conservation of the mass, monotonicity and accuracy are the most relevant concerns.
NASA Astrophysics Data System (ADS)
Núñez-de la Rosa, Jonatan; Munz, Claus-Dieter
2016-02-01
The present work describes the building blocks of a new code for computational magnetohydrodynamics based on very high order finite volume methods on Cartesian meshes. Spatial high-order accuracy is obtained with a weighted essentially non-oscillatory (WENO) reconstruction operator up to seventh order, while the time discretization is performed with a fourth-order strong-stability preserving Runge-Kutta method. Based on a shock-detection approach, the reconstruction operator employs a very high order WENO scheme in smooth flow regions and a third-order WENO scheme in those parts of the flow with discontinuities or shocks. The generalized Lagrange multiplier method is employed to enforce the solenoidal constraint on the magnetic field. Extensive numerical computations in one and two space dimensions are reported. Convergence rates for smooth flows verify the high-order accuracy of the scheme, and tests with strong shocks, including the Orszag-Tang vortex, the cylindrical blast wave problem, the rotor problem, and the Kelvin-Helmholtz instability, confirm the robustness and stability of the approach.
High-order central Hermite WENO schemes: Dimension-by-dimension moment-based reconstructions
NASA Astrophysics Data System (ADS)
Tao, Zhanjing; Li, Fengyan; Qiu, Jianxian
2016-08-01
In this paper, a class of high-order central finite volume schemes is proposed for solving one- and two-dimensional hyperbolic conservation laws. Formulated on staggered meshes, the methods involve Hermite WENO (HWENO) spatial reconstructions, and Lax-Wendroff type discretizations or the natural continuous extension of Runge-Kutta methods in time. Differently from the central Hermite WENO methods we developed previously in Tao et al. (2015) [34], the spatial reconstructions, a core ingredient of the methods, are based on the zeroth-order and the first-order moments of the solution, and are implemented through a dimension-by-dimension strategy when the spatial dimension is higher than one. This leads to much simpler implementation of the methods in higher dimension and better cost efficiency. Meanwhile, the proposed methods have the attractive features of the general central Hermite WENO methods such as being compact in reconstruction and requiring neither flux splitting nor numerical fluxes, while being accurate and essentially non-oscillatory. A collection of one- and two-dimensional numerical examples is presented to demonstrate high resolution and robustness of the methods in capturing smooth and non-smooth solutions.
NASA Technical Reports Server (NTRS)
Jothiprasad, Giridhar; Mavriplis, Dimitri J.; Caughey, David A.; Bushnell, Dennis M. (Technical Monitor)
2002-01-01
The efficiency gains obtained using higher-order implicit Runge-Kutta schemes as compared with the second-order accurate backward difference schemes for the unsteady Navier-Stokes equations are investigated. Three different algorithms for solving the nonlinear system of equations arising at each timestep are presented. The first algorithm (NMG) is a pseudo-time-stepping scheme which employs a non-linear full approximation storage (FAS) agglomeration multigrid method to accelerate convergence. The other two algorithms are based on Inexact Newton's methods. The linear system arising at each Newton step is solved using iterative/Krylov techniques and left preconditioning is used to accelerate convergence of the linear solvers. One of the methods (LMG) uses Richardson's iterative scheme for solving the linear system at each Newton step while the other (PGMRES) uses the Generalized Minimal Residual method. Results demonstrating the relative superiority of these Newton's methods based schemes are presented. Efficiency gains as high as 10 are obtained by combining the higher-order time integration schemes with the more efficient nonlinear solvers.
European Code against Cancer, 4th Edition: Cancer screening.
Armaroli, Paola; Villain, Patricia; Suonio, Eero; Almonte, Maribel; Anttila, Ahti; Atkin, Wendy S; Dean, Peter B; de Koning, Harry J; Dillner, Lena; Herrero, Rolando; Kuipers, Ernst J; Lansdorp-Vogelaar, Iris; Minozzi, Silvia; Paci, Eugenio; Regula, Jaroslaw; Törnberg, Sven; Segnan, Nereo
2015-12-01
In order to update the previous version of the European Code against Cancer and formulate evidence-based recommendations, a systematic search of the literature was performed according to the methodology agreed by the Code Working Groups. Based on the review, the 4th edition of the European Code against Cancer recommends: "Take part in organized cancer screening programmes for: Bowel cancer (men and women); Breast cancer (women); Cervical cancer (women)." Organized screening programs are preferable because they provide better conditions to ensure that the Guidelines for Quality Assurance in Screening are followed in order to achieve the greatest benefit with the least harm. Screening is recommended only for those cancers where a demonstrated life-saving effect substantially outweighs the potential harm of examining very large numbers of people who may otherwise never have, or suffer from, these cancers, and when an adequate quality of the screening is achieved. EU citizens are recommended to participate in cancer screening each time an invitation from the national or regional screening program is received and after having read the information materials provided and carefully considered the potential benefits and harms of screening. Screening programs in the European Union vary with respect to the age groups invited and to the interval between invitations, depending on each country's cancer burden, local resources, and the type of screening test used For colorectal cancer, most programs in the EU invite men and women starting at the age of 50-60 years, and from then on every 2 years if the screening test is the guaiac-based fecal occult blood test or fecal immunochemical test, or every 10 years or more if the screening test is flexible sigmoidoscopy or total colonoscopy. Most programs continue sending invitations to screening up to the age of 70-75 years. For breast cancer, most programs in the EU invite women starting at the age of 50 years, and not before the age
European Code against Cancer, 4th Edition: Cancer screening.
Armaroli, Paola; Villain, Patricia; Suonio, Eero; Almonte, Maribel; Anttila, Ahti; Atkin, Wendy S; Dean, Peter B; de Koning, Harry J; Dillner, Lena; Herrero, Rolando; Kuipers, Ernst J; Lansdorp-Vogelaar, Iris; Minozzi, Silvia; Paci, Eugenio; Regula, Jaroslaw; Törnberg, Sven; Segnan, Nereo
2015-12-01
In order to update the previous version of the European Code against Cancer and formulate evidence-based recommendations, a systematic search of the literature was performed according to the methodology agreed by the Code Working Groups. Based on the review, the 4th edition of the European Code against Cancer recommends: "Take part in organized cancer screening programmes for: Bowel cancer (men and women); Breast cancer (women); Cervical cancer (women)." Organized screening programs are preferable because they provide better conditions to ensure that the Guidelines for Quality Assurance in Screening are followed in order to achieve the greatest benefit with the least harm. Screening is recommended only for those cancers where a demonstrated life-saving effect substantially outweighs the potential harm of examining very large numbers of people who may otherwise never have, or suffer from, these cancers, and when an adequate quality of the screening is achieved. EU citizens are recommended to participate in cancer screening each time an invitation from the national or regional screening program is received and after having read the information materials provided and carefully considered the potential benefits and harms of screening. Screening programs in the European Union vary with respect to the age groups invited and to the interval between invitations, depending on each country's cancer burden, local resources, and the type of screening test used For colorectal cancer, most programs in the EU invite men and women starting at the age of 50-60 years, and from then on every 2 years if the screening test is the guaiac-based fecal occult blood test or fecal immunochemical test, or every 10 years or more if the screening test is flexible sigmoidoscopy or total colonoscopy. Most programs continue sending invitations to screening up to the age of 70-75 years. For breast cancer, most programs in the EU invite women starting at the age of 50 years, and not before the age
NASA Astrophysics Data System (ADS)
Pan, Liang; Xu, Kun
2016-08-01
In this paper, for the first time a third-order compact gas-kinetic scheme is proposed on unstructured meshes for the compressible viscous flow computations. The possibility to design such a third-order compact scheme is due to the high-order gas evolution model, where a time-dependent gas distribution function at cell interface not only provides the fluxes across a cell interface, but also presents a time accurate solution for flow variables at cell interface. As a result, both cell averaged and cell interface flow variables can be used for the initial data reconstruction at the beginning of next time step. A weighted least-square procedure has been used for the initial reconstruction. Therefore, a compact third-order gas-kinetic scheme with the involvement of neighboring cells only can be developed on unstructured meshes. In comparison with other conventional high-order schemes, the current method avoids the Gaussian point integration for numerical fluxes along a cell interface and the multi-stage Runge-Kutta method for temporal accuracy. The third-order compact scheme is numerically stable under CFL condition CFL ≈ 0.5. Due to its multidimensional gas-kinetic formulation and the coupling of inviscid and viscous terms, even with unstructured meshes, the boundary layer solution and vortex structure can be accurately captured by the current scheme. At the same time, the compact scheme can capture strong shocks as well.
A higher-order implicit IDO scheme and its CFD application to local mesh refinement method
NASA Astrophysics Data System (ADS)
Imai, Yohsuke; Aoki, Takayuki
2006-08-01
The Interpolated Differential Operator (IDO) scheme has been developed for the numerical solution of the fluid motion equations, and allows to produce highly accurate results by introducing the spatial derivative of the physical value as an additional dependent variable. For incompressible flows, semi-implicit time integration is strongly affected by the Courant and diffusion number limitation. A high-order fully-implicit IDO scheme is presented, and the two-stage implicit Runge-Kutta time integration keeps over third-order accuracy. The application of the method to the direct numerical simulation of turbulence demonstrates that the proposed scheme retains a resolution comparable to that of spectral methods even for relatively large Courant numbers. The scheme is further applied to the Local Mesh Refinement (LMR) method, where the size of the time step is often restricted by the dimension of the smallest meshes. In the computation of the Karman vortex street problem, the implicit IDO scheme with LMR is shown to allow a conspicuous saving of computational resources.
Computations of Flow over a Hump Model Using Higher Order Method with Turbulence Modeling
NASA Technical Reports Server (NTRS)
Balakumar, P.
2005-01-01
Turbulent separated flow over a two-dimensional hump is computed by solving the RANS equations with k - omega (SST) turbulence model for the baseline, steady suction and oscillatory blowing/suction flow control cases. The flow equations and the turbulent model equations are solved using a fifth-order accurate weighted essentially. nonoscillatory (WENO) scheme for space discretization and a third order, total variation diminishing (TVD) Runge-Kutta scheme for time integration. Qualitatively the computed pressure distributions exhibit the same behavior as those observed in the experiments. The computed separation regions are much longer than those observed experimentally. However, the percentage reduction in the separation region in the steady suction case is closer to what was measured in the experiment. The computations did not predict the expected reduction in the separation length in the oscillatory case. The predicted turbulent quantities are two to three times smaller than the measured values pointing towards the deficiencies in the existing turbulent models when they are applied to strong steady/unsteady separated flows.
Parallel Adjective High-Order CFD Simulations Characterizing SOFIA Cavity Acoustics
NASA Technical Reports Server (NTRS)
Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.; Biswas, Rupak
2016-01-01
This paper presents large-scale MPI-parallel computational uid dynamics simulations for the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne, 2.5-meter infrared telescope mounted in an open cavity in the aft fuselage of a Boeing 747SP. These simulations focus on how the unsteady ow eld inside and over the cavity interferes with the optical path and mounting structure of the telescope. A temporally fourth-order accurate Runge-Kutta, and spatially fth-order accurate WENO- 5Z scheme was used to perform implicit large eddy simulations. An immersed boundary method provides automated gridding for complex geometries and natural coupling to a block-structured Cartesian adaptive mesh re nement framework. Strong scaling studies using NASA's Pleiades supercomputer with up to 32k CPU cores and 4 billion compu- tational cells shows excellent scaling. Dynamic load balancing based on execution time on individual AMR blocks addresses irregular numerical cost associated with blocks con- taining boundaries. Limits to scaling beyond 32k cores are identi ed, and targeted code optimizations are discussed.
4th International Plant Biomechanics Conference Proceedings (Abstracts)
Frank W. Telewski; Lothar H. Koehler; Frank W. Ewers
2003-07-20
The 4th International Plant Biomechanics Conference facilitated an interdisciplinary exchange between scientists, engineers, and educators addressing the major questions encountered in the field of Plant Biomechanics. Subjects covered by the conference include: Evolution; Ecology; Mechanoreception; Cell Walls; Genetic Modification; Applied Biomechanics of Whole Plants, Plant Products, Fibers & Composites; Fluid Dynamics; Wood & Trees; Fracture Mechanics; Xylem Pressure & Water Transport; Modeling; and Introducing Plant Biomechanics in Secondary School Education.
Time Integration Schemes for the Unsteady Navier-stokes Equations
NASA Technical Reports Server (NTRS)
Bijl, Hester; Carpenter, Mark H.; Vatsa, Veer N.
2001-01-01
The efficiency and accuracy of several time integration schemes are investigated for the unsteady Navier-Stokes equations. This study focuses on the efficiency of higher-order Runge-Kutta schemes in comparison with the popular Backward Differencing Formulations. For this comparison an unsteady two-dimensional laminar flow problem is chosen, i.e., flow around a circular cylinder at Re = 1200. It is concluded that for realistic error tolerances (smaller than 10(exp -1)) fourth-and fifth-order Runge-Kutta schemes are the most efficient. For reasons of robustness and computer storage, the fourth-order Runge-Kutta method is recommended. The efficiency of the fourth-order Runge-Kutta scheme exceeds that of second-order Backward Difference Formula by a factor of 2.5 at engineering error tolerance levels (10(exp -1) to 10(exp -2)). Efficiency gains are more dramatic at smaller tolerances.
NASA Astrophysics Data System (ADS)
Greene, Patrick T.; Eldredge, Jeff D.; Zhong, Xiaolin; Kim, John
2016-07-01
In this paper, we present a method for performing uniformly high-order direct numerical simulations of high-speed flows over arbitrary geometries. The method was developed with the goal of simulating and studying the effects of complex isolated roughness elements on the stability of hypersonic boundary layers. The simulations are carried out on Cartesian grids with the geometries imposed by a third-order cut-stencil method. A fifth-order hybrid weighted essentially non-oscillatory scheme was implemented to capture any steep gradients in the flow created by the geometries and a third-order Runge-Kutta method is used for time advancement. A multi-zone refinement method was also utilized to provide extra resolution at locations with expected complex physics. The combination results in a globally fourth-order scheme in space and third order in time. Results confirming the method's high order of convergence are shown. Two-dimensional and three-dimensional test cases are presented and show good agreement with previous results. A simulation of Mach 3 flow over the logo of the Ubuntu Linux distribution is shown to demonstrate the method's capabilities for handling complex geometries. Results for Mach 6 wall-bounded flow over a three-dimensional cylindrical roughness element are also presented. The results demonstrate that the method is a promising tool for the study of hypersonic roughness-induced transition.
a Numerical Comparison of Langrange and Kane's Methods of AN Arm Segment
NASA Astrophysics Data System (ADS)
Rambely, Azmin Sham; Halim, Norhafiza Ab.; Ahmad, Rokiah Rozita
A 2-D model of a two-link kinematic chain is developed using two dynamics equations of motion, namely Kane's and Lagrange Methods. The dynamics equations are reduced to first order differential equation and solved using modified Euler and fourth order Runge Kutta to approximate the shoulder and elbow joint angles during a smash performance in badminton. Results showed that Runge-Kutta produced a better and exact approximation than that of modified Euler and both dynamic equations produced better absolute errors.
A Review of High-Order and Optimized Finite-Difference Methods for Simulating Linear Wave Phenomena
NASA Technical Reports Server (NTRS)
Zingg, David W.
1996-01-01
This paper presents a review of high-order and optimized finite-difference methods for numerically simulating the propagation and scattering of linear waves, such as electromagnetic, acoustic, or elastic waves. The spatial operators reviewed include compact schemes, non-compact schemes, schemes on staggered grids, and schemes which are optimized to produce specific characteristics. The time-marching methods discussed include Runge-Kutta methods, Adams-Bashforth methods, and the leapfrog method. In addition, the following fourth-order fully-discrete finite-difference methods are considered: a one-step implicit scheme with a three-point spatial stencil, a one-step explicit scheme with a five-point spatial stencil, and a two-step explicit scheme with a five-point spatial stencil. For each method studied, the number of grid points per wavelength required for accurate simulation of wave propagation over large distances is presented. Recommendations are made with respect to the suitability of the methods for specific problems and practical aspects of their use, such as appropriate Courant numbers and grid densities. Avenues for future research are suggested.
NASA Astrophysics Data System (ADS)
Yu, Cong
2011-03-01
The force-free (or low inertia) limit of magnetohydrodynamics (MHD) can be applied to many astrophysical objects, including black holes, neutron stars and accretion discs, where the electromagnetic field is so strong that the inertia and pressure of the plasma can be ignored. This is difficult to achieve with the standard MHD numerical methods because they still have to deal with plasma inertial terms even when these terms are much smaller than the electromagnetic terms. Under the force-free approximation, the plasma dynamics is entirely determined by the magnetic field. The plasma provides the currents and charge densities required by the dynamics of electromagnetic fields, but these currents carry no inertia. We present a high-order Godunov scheme to study such force-free electrodynamics. We have implemented weighted essentially non-oscillatory (WENO) spatial interpolations in our scheme. An exact Riemann solver is implemented, which requires spectral decomposition into characteristic waves. We advance the magnetic field with the constrained transport (CT) scheme to preserve the divergence-free condition to machine round-off error. We apply the third-order total variation diminishing (TVD) Runge-Kutta scheme for the temporal integration. The mapping from face-centred variables to volume-centred variables is carefully considered. Extensive testing are performed to demonstrate the ability of our scheme to address force-free electrodynamics correctly. We finally apply the scheme to study relativistic magnetically dominated tearing instabilities and neutron star magnetospheres.
High Order Difference Method for Low Mach Number Aeroacoustics
NASA Technical Reports Server (NTRS)
Mueller, B.; Yee, H. C.; Mansour, Nagi (Technical Monitor)
2001-01-01
A high order finite difference method with improved accuracy and stability properties for computational aeroacoustics (CAA) at low Mach numbers is proposed. The Euler equations are split into a conservative and a symmetric non- conservative portion to allow the derivation of a generalized energy estimate. Since the symmetrization is based on entropy variables, that splitting of the flux derivatives is referred to as entropy splitting. Its discretization by high order central differences was found to need less numerical dissipation than conventional conservative schemes. Owing to the large disparity of acoustic and stagnation quantities in low Mach number aeroacoustics, the split Euler equations are formulated in perturbation form. The unknowns are the small changes of the conservative variables with respect to their large stagnation values. All nonlinearities and the conservation form of the conservative portion of the split flux derivatives can be retained, while cancellation errors are avoided with its discretization opposed to the conventional conservative form. The finite difference method is third-order accurate at the boundary and the conventional central sixth-order accurate stencil in the interior. The difference operator satisfies the summation by parts property analogous to the integration by parts in the continuous energy estimate. Thus, strict stability of the difference method follows automatically. Spurious high frequency oscillations are suppressed by a characteristic-based filter similar to but without limiter. The time derivative is approximated by a 4-stage low-storage second-order explicit Runge-Kutta method. The method has been applied to simulate vortex sound at low Mach numbers. We consider the Kirchhoff vortex, which is an elliptical patch of constant vorticity rotating with constant angular frequency in irrotational flow. The acoustic pressure generated by the Kirchhoff vortex is governed by the 2D Helmholtz equation, which can be solved
NASA Astrophysics Data System (ADS)
Motheau, E.; Abraham, J.
2016-05-01
A novel and efficient algorithm is presented in this paper to deal with DNS of turbulent reacting flows under the low-Mach-number assumption, with detailed chemistry and a quasi-spectral accuracy. The temporal integration of the equations relies on an operating-split strategy, where chemical reactions are solved implicitly with a stiff solver and the convection-diffusion operators are solved with a Runge-Kutta-Chebyshev method. The spatial discretisation is performed with high-order compact schemes, and a FFT based constant-coefficient spectral solver is employed to solve a variable-coefficient Poisson equation. The numerical implementation takes advantage of the 2DECOMP&FFT libraries developed by [1], which are based on a pencil decomposition method of the domain and are proven to be computationally very efficient. An enhanced pressure-correction method is proposed to speed up the achievement of machine precision accuracy. It is demonstrated that a second-order accuracy is reached in time, while the spatial accuracy ranges from fourth-order to sixth-order depending on the set of imposed boundary conditions. The software developed to implement the present algorithm is called HOLOMAC, and its numerical efficiency opens the way to deal with DNS of reacting flows to understand complex turbulent and chemical phenomena in flames.
Special Issue: 4th International Workshop on Space Radiation (IWSRR)
NASA Technical Reports Server (NTRS)
Cucinotta, Francis A.
2007-01-01
This special issue of the journal "Radiation and Environmental Biophysics" contains 20 peer-reviewed papers contributed by leading space radiation researcher's world-wide attending the 4th IWSRR. Manuscripts cover a broad range of topics ranging from radiation environments and transport in shielding and planetary surfaces to new results in understanding the biological effects of protons and high-charge and energy (HZE) nuclei on the risk of cancer, and degenerative diseases such as central nervous system effects, heart disease, and cataracts. The issue provides a snapshot of the state-of-the-art of the research in this field, demonstrating both the important results gathered in the past few years with experiments at accelerators, and the need for more research to quantify the risk and develop countermeasures.
The Epilepsy Foundation's 4th Biennial Epilepsy Pipeline Update Conference.
French, Jacqueline A; Schachter, Steven C; Sirven, Joseph; Porter, Roger
2015-05-01
On June 5 and 6, 2014, the Epilepsy Foundation held its 4th Biennial Epilepsy Pipeline Update Conference, an initiative of the Epilepsy Therapy Project, which showcased the most promising epilepsy innovations from health-care companies and academic laboratories dedicated to pioneering and advancing drugs, biologics, technologies, devices, and diagnostics for epilepsy. Speakers and attendees included emerging biotech and medical technology companies, major pharmaceutical and device companies, as well as investigators and innovators at the cutting-edge of epilepsy. The program included panel discussions on collaboration between small and large companies, how to get products in need of funding to the marketplace, who is currently funding epilepsy and CNS innovation, and how the NIH facilitates early-stage drug development. Finally, the conference featured the third annual "Shark Tank" competition. The presentations are summarized in this paper, which is followed by a compilation of the meeting poster abstracts. PMID:25922152
ERIC Educational Resources Information Center
Nam, Younkyeong; Karahan, Engin; Roehrig, Gillian
2016-01-01
Geologic time scale is a very important concept for understanding long-term earth system events such as climate change. This study examines forty-three 4th-8th grade Native American--particularly Ojibwe tribe--students' understanding of relative ordering and absolute time of Earth's significant geological and biological events. This study also…
A second-order parareal algorithm for fractional PDEs
NASA Astrophysics Data System (ADS)
Wu, Shu-Lin
2016-02-01
We are concerned with using the parareal (parallel-in-time) algorithm for large scale ODEs system U‧ (t) + AU (t) + dAα U (t) = F (t) arising frequently in semi-discretizing time-dependent PDEs with spatial fractional operators, where d > 0 is a constant, α ∈ (0 , 1) and A is a spare and symmetric positive definite (SPD) matrix. The parareal algorithm is iterative and is characterized by two propagators F and G, which are respectively associated with small temporal mesh size Δt and large temporal mesh size ΔT. The two mesh sizes satisfy ΔT = JΔt with J ≥ 2 being an integer, which is called mesh ratio. Let Tunitf and Tunitg be respectively the computational cost of the two propagators for moving forward one time step. Then, it is well understood that the speedup of the parareal algorithm, namely E, satisfies E = O (clog (1 / ρ)) , where c : = Tunitf / Tunitg and ρ is the convergence factor. A larger E corresponds a more efficient parareal solver. For G = Backward-Euler and some choices of F, previous studies show that ρ can be a satisfactory quantity. Particularly, for F = 2nd-order DIRK (diagonally implicit Runge-Kutta), it holds ρ ≈1/3 for any choice of the mesh ratio J. In this paper, we continue to consider F = 2nd-order DIRK, but with a new choice for G, the IMEX (implicit-explicit) Euler method, where the 'implicit' and 'explicit' computation is respectively associated with A and dAα. Compared to the widely used Backward-Euler method, this choice on the one hand increases c (this point is apparent), and interestingly on the other hand it can also make the convergence factor ρ smaller: ρ ≈1/5! Numerical results are provided to support our conclusions.
High-Order Space-Time Methods for Conservation Laws
NASA Technical Reports Server (NTRS)
Huynh, H. T.
2013-01-01
Current high-order methods such as discontinuous Galerkin and/or flux reconstruction can provide effective discretization for the spatial derivatives. Together with a time discretization, such methods result in either too small a time step size in the case of an explicit scheme or a very large system in the case of an implicit one. To tackle these problems, two new high-order space-time schemes for conservation laws are introduced: the first is explicit and the second, implicit. The explicit method here, also called the moment scheme, achieves a Courant-Friedrichs-Lewy (CFL) condition of 1 for the case of one-spatial dimension regardless of the degree of the polynomial approximation. (For standard explicit methods, if the spatial approximation is of degree p, then the time step sizes are typically proportional to 1/p(exp 2)). Fourier analyses for the one and two-dimensional cases are carried out. The property of super accuracy (or super convergence) is discussed. The implicit method is a simplified but optimal version of the discontinuous Galerkin scheme applied to time. It reduces to a collocation implicit Runge-Kutta (RK) method for ordinary differential equations (ODE) called Radau IIA. The explicit and implicit schemes are closely related since they employ the same intermediate time levels, and the former can serve as a key building block in an iterative procedure for the latter. A limiting technique for the piecewise linear scheme is also discussed. The technique can suppress oscillations near a discontinuity while preserving accuracy near extrema. Preliminary numerical results are shown
76 FR 37649 - Safety Zone; Northern California Annual Fireworks Events, July 4th Fireworks Display
Federal Register 2010, 2011, 2012, 2013, 2014
2011-06-28
... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Northern California Annual Fireworks Events, July 4th Fireworks Display AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement of regulation. SUMMARY: The Coast Guard will enforce safety zone for the annual July 4th Fireworks Display (Tahoe City 4th of...
Comparative study of numerical schemes of TVD3, UNO3-ACM and optimized compact scheme
NASA Technical Reports Server (NTRS)
Lee, Duck-Joo; Hwang, Chang-Jeon; Ko, Duck-Kon; Kim, Jae-Wook
1995-01-01
Three different schemes are employed to solve the benchmark problem. The first one is a conventional TVD-MUSCL (Monotone Upwind Schemes for Conservation Laws) scheme. The second scheme is a UNO3-ACM (Uniformly Non-Oscillatory Artificial Compression Method) scheme. The third scheme is an optimized compact finite difference scheme modified by us: the 4th order Runge Kutta time stepping, the 4th order pentadiagonal compact spatial discretization with the maximum resolution characteristics. The problems of category 1 are solved by using the second (UNO3-ACM) and third (Optimized Compact) schemes. The problems of category 2 are solved by using the first (TVD3) and second (UNO3-ACM) schemes. The problem of category 5 is solved by using the first (TVD3) scheme. It can be concluded from the present calculations that the Optimized Compact scheme and the UN03-ACM show good resolutions for category 1 and category 2 respectively.
PREFACE: 4th International Symposium on Functional Materials (ISFM2011)
NASA Astrophysics Data System (ADS)
Yin, Shu; Sekino, Tohru; Tanaka, Shun-ichiro; Sato, Tsugio; Lu, Li; Xue, Dongfeng
2012-01-01
The 4th International Symposium on Functional Materials (ISFM2011) was held in Sendai, Japan, on 2-6 August 2011. This Special Issue of Journal of Physics: Conference Series (JPCS) consists of partial manuscripts which were presented at ISFM2011. Advanced materials have experienced a dramatic increase in demand for research, development and applications. The aim of the International Symposium on Functional Materials (ISFM) was to provide an overview of the present status with historical background and to foresee future trends in the field of functional materials. The 4th symposium, ISFM 2011, covered a wide variety of topics within state-of-the-art advanced materials science and technology, and focused especially on four major categories including: Environmental Materials, Electronic Materials, Energy Materials and Biomedical Materials. As you know, a massive earthquake and the Tsunami that followed occurred near the Tohoku region on 11 March 2011. After the earthquake, although there were many difficulties in continuing to organize the symposium, we received warm encouragement from many researchers and societies, especially from the members of the International Advisory Committee and Organizing Committee, so that ISFM2011 could be held on schedule. We are honored that ISFM2011 was the first formal international academic conference held in the Tohoku area of Japan after the 11 March earthquake. About 140 participants from 14 countries took part in the ISFM2011 symposium, which included five plenary talks by world-leading scientists, 32 invited talks, and many oral and poster presentations. We are delighted to see that many researchers are interested in the synthesis and the properties as well as the applications of functional materials. Many fruitful and exciting research achievements were presented in the symposium. We believe that this symposium provided a good chance for scientists to communicate and exchange opinions with each other. We would also like to
NASA Astrophysics Data System (ADS)
Belmonte, Juan Antonio
2015-08-01
The pyramids of Egypt, notably those of the 4th Dinasty as Giza, have always be considered an unmistikable part of human world heritage as the only surviving wonders of the Ancient World. Their majesty, technical hability and innovative character have always beeen considered as representative of ancient Egyptian ingenuity. However, past and present fringe theories about the pyramids and astronomy have always polluted the role of our discipline in the design, construction and symbolism of these impressive monuments. This is indeed unfear. Fortunately, things have started to change in the last couple of decades and now astronomy is interpreted as a neccessary tool for the correct interpretation of the astral eschatology present in the 5th and 6th Dynasty Texts of the Pyramids. Although the pyramid complexes of the 4th Dynasty are mute, there is however recent research showing that a strong astral symbolism could be hidden in many aspects of the complex architecture and in the design of these exceptional monuments. This idea comes from several hints obtained not only from planning and construction, but also from epigraphy and the analysis of celestial and local landscapes. Chronology also plays a most relevant role on this. The pyramid complexes of the 4th Dynasty at Meidum, Dahshur, Giza and Abu Rowash -- all of which enjoy UNESCO World Heritage recognition -- willl be scrutinized. As a consequence, we will show how astronomy can certainly enhance the face value of these extraordinary monuments as a definitive proof of the ancient Egyptian quest for Ma'at, i.e. their perennial obsesion for Cosmic Order.
Managing haemophilia for life: 4th Haemophilia Global Summit.
Astermark, J; Dolan, G; Hilberg, T; Jiménez-Yuste, V; Laffan, M; Lassila, R; Lobet, S; Martinoli, C; Perno, C-F
2014-07-01
The 4th Haemophilia Global Summit was held in Potsdam, Germany, in September 2013 and brought together an international faculty of haemophilia experts and delegates from multidisciplinary backgrounds. The programme was designed by an independent Scientific Steering Committee of haemophilia experts and explored global perspectives in haemophilia care, discussing practical approaches to the optimal management of haemophilia now and in the future. The topics outlined in this supplement were selected by the Scientific Steering Committee for their relevance and potential to influence haemophilia care globally. In this supplement from the meeting, Jan Astermark reviews current understanding of risk factors for the development of inhibitory antibodies and discusses whether this risk can be modulated and minimized. Factors key to the improvement of joint health in people with haemophilia are explored, with Carlo Martinoli and Víctor Jiménez-Yuste discussing the utility of ultrasound for the early detection of haemophilic arthropathy. Other aspects of care necessary for the prevention and management of joint disease in people with haemophilia are outlined by Thomas Hilberg and Sébastian Lobet, who highlight the therapeutic benefits of physiotherapy and sports therapy. Riitta Lassila and Carlo-Federico Perno describe current knowledge surrounding the risk of transmission of infectious agents via clotting factor concentrates. Finally, different types of extended half-life technology are evaluated by Mike Laffan, with a focus on the practicalities and challenges associated with these products.
European Code against Cancer 4th Edition: Diet and cancer.
Norat, Teresa; Scoccianti, Chiara; Boutron-Ruault, Marie-Christine; Anderson, Annie; Berrino, Franco; Cecchini, Michele; Espina, Carolina; Key, Tim; Leitzmann, Michael; Powers, Hilary; Wiseman, Martin; Romieu, Isabelle
2015-12-01
Lifestyle factors, including diet, have long been recognised as potentially important determinants of cancer risk. In addition to the significant role diet plays in affecting body fatness, a risk factor for several cancers, experimental studies have indicated that diet may influence the cancer process in several ways. Prospective studies have shown that dietary patterns characterised by higher intakes of fruits, vegetables, and whole-grain foods, and lower intakes of red and processed meats and salt, are related to reduced risks of death and cancer, and that a healthy diet can improve overall survival after diagnosis of breast and colorectal cancers. There is evidence that high intakes of fruit and vegetables may reduce the risk of cancers of the aerodigestive tract, and the evidence that dietary fibre protects against colorectal cancer is convincing. Red and processed meats increase the risk of colorectal cancer. Diets rich in high-calorie foods, such as fatty and sugary foods, may lead to increased calorie intake, thereby promoting obesity and leading to an increased risk of cancer. There is some evidence that sugary drinks are related to an increased risk of pancreatic cancer. Taking this evidence into account, the 4th edition of the European Code against Cancer recommends that people have a healthy diet to reduce their risk of cancer: they should eat plenty of whole grains, pulses, vegetables and fruits; limit high-calorie foods (foods high in sugar or fat); avoid sugary drinks and processed meat; and limit red meat and foods high in salt.
European Code against Cancer 4th Edition: Diet and cancer.
Norat, Teresa; Scoccianti, Chiara; Boutron-Ruault, Marie-Christine; Anderson, Annie; Berrino, Franco; Cecchini, Michele; Espina, Carolina; Key, Tim; Leitzmann, Michael; Powers, Hilary; Wiseman, Martin; Romieu, Isabelle
2015-12-01
Lifestyle factors, including diet, have long been recognised as potentially important determinants of cancer risk. In addition to the significant role diet plays in affecting body fatness, a risk factor for several cancers, experimental studies have indicated that diet may influence the cancer process in several ways. Prospective studies have shown that dietary patterns characterised by higher intakes of fruits, vegetables, and whole-grain foods, and lower intakes of red and processed meats and salt, are related to reduced risks of death and cancer, and that a healthy diet can improve overall survival after diagnosis of breast and colorectal cancers. There is evidence that high intakes of fruit and vegetables may reduce the risk of cancers of the aerodigestive tract, and the evidence that dietary fibre protects against colorectal cancer is convincing. Red and processed meats increase the risk of colorectal cancer. Diets rich in high-calorie foods, such as fatty and sugary foods, may lead to increased calorie intake, thereby promoting obesity and leading to an increased risk of cancer. There is some evidence that sugary drinks are related to an increased risk of pancreatic cancer. Taking this evidence into account, the 4th edition of the European Code against Cancer recommends that people have a healthy diet to reduce their risk of cancer: they should eat plenty of whole grains, pulses, vegetables and fruits; limit high-calorie foods (foods high in sugar or fat); avoid sugary drinks and processed meat; and limit red meat and foods high in salt. PMID:26164653
Variational Symplectic Orbit Code in 3-D Tokamak Geometry
NASA Astrophysics Data System (ADS)
Ellison, Charles; Qin, Hong; Tang, William M.
2011-10-01
Since advanced tokamak experiments - including ITER - are long-pulse systems, it is important to develop accurate numerical methods to track plasma dynamics over an extended temporal period. When attempting to model the motion of individual particles, standard integrators (e.g. 4th order Runge-Kutta) discretize the differential equations of motion - but do not possess desired properties such as energy conservation. The variational symplectic integrator adopts instead a different approach via minimizing the action of the guiding center motion to determine iteration rules. Consequently, the Lagrangian symplectic structure is conserved, and the numerical energy error is bounded by a small number for all time-steps. In previous work, the theoretical basis for this method was introduced, but the implementation was for 2-D geometry. To address realistic experimental scenarios, the variational symplectic integrator has been implemented for 3-D tokamak geometry for the first time. Sample results will be presented and compared with those from standard Runge-Kutta-based 3-D tokamak orbit codes. This work was supported by the DOE contract # DE-AC02-09CH11466 and the DOE FES Fellowship.
Adaptive Numerical Dissipative Control in High Order Schemes for Multi-D Non-Ideal MHD
NASA Technical Reports Server (NTRS)
Yee, H. C.; Sjoegreen, B.
2004-01-01
derivatives and a fourth-order Runge-Kutta method are denoted.
European Code against Cancer, 4th Edition: Tobacco and cancer.
Leon, Maria E; Peruga, Armando; McNeill, Ann; Kralikova, Eva; Guha, Neela; Minozzi, Silvia; Espina, Carolina; Schüz, Joachim
2015-12-01
Tobacco use, and in particular cigarette smoking, is the single largest preventable cause of cancer in the European Union (EU). All tobacco products contain a wide range of carcinogens. The main cancer-causing agents in tobacco smoke are polycyclic aromatic hydrocarbons, tobacco-specific N-nitrosamines, aromatic amines, aldehydes, and certain volatile organic compounds. Tobacco consumers are also exposed to nicotine, leading to tobacco addiction in many users. Cigarette smoking causes cancer in multiple organs and is the main cause of lung cancer, responsible for approximately 82% of cases. In 2012, about 313,000 new cases of lung cancer and 268,000 lung cancer deaths were reported in the EU; 28% of adults in the EU smoked tobacco, and the overall prevalence of current use of smokeless tobacco products was almost 2%. Smokeless tobacco products, a heterogeneous category, are also carcinogenic but cause a lower burden of cancer deaths than tobacco smoking. One low-nitrosamine product, snus, is associated with much lower cancer risk than other smokeless tobacco products. Smoking generates second-hand smoke (SHS), an established cause of lung cancer, and inhalation of SHS by non-smokers is still common in indoor workplaces as well as indoor public places, and more so in the homes of smokers. Several interventions have proved effective for stopping smoking; the most effective intervention is the use of a combination of pharmacotherapy and behavioural support. Scientific evidence leads to the following two recommendations for individual action on tobacco in the 4th edition of the European Code Against Cancer: (1) "Do not smoke. Do not use any form of tobacco"; (2) "Make your home smoke-free. Support smoke-free policies in your workplace". PMID:26272517
Results of 4th repeated levelling survey in Estonia
NASA Astrophysics Data System (ADS)
Kall, Tarmo; Torim, Ants; Jürma, Helju; Liibusk, Aive; Jürgenson, Harli
2010-05-01
Estonian precise levelling network consists of about 2000 km levelling lines and 1300 benchmarks. Three precise repeated levellings were carried out: in 1933-1943, 1948-1969 and 1970-1996. Three height systems have been realized: Tallinn Height System (unofficial system), Baltic Height System of 1951 and Baltic Height System of 1977 (BK77). Campaign of 4th repeated levelling was started at 2004 with goal to reconstruct the destroyed and damaged benchmarks, to realize the new height system and concept of integrated geodetic network. Reconstructed levelling network will consist of approximately 3000 km levelling lines and 2300 benchmarks. Digital level DiNi and NEDO invar code rod is used for levelling. Levellings carried out so far is characterized by high precision: levelling error calculated using levelling loops closing error is 0.23 mm/km. In the end of 2010 is planned to complete the levelling field work. After that the processing of the levelling data and the realization of the new height system will be implemented. Goal of the present study was to adjust the height differences of the latest repeated levelling and compare obtained benchmarks heights with previous ones. Method of the least squares and software SBG GEO 2005 was used for adjustment. Minimally constrained adjustment with one fixed benchmarks was used. Location of the benchmark was chosen in the area of minimal postglacial land uplift. Obtained benchmark heights are preliminary because no rod calibration, refraction etc. corrections were added yet to field height differences. Therefore obtained heights are not realization of the new height system. Still obtained heights can be used for example for improving of Estonian geoid model. In comparison between new and old benchmark heights, SE-NW directional pattern of postglacial land uplift appeared as expected.
European Code against Cancer, 4th Edition: Tobacco and cancer.
Leon, Maria E; Peruga, Armando; McNeill, Ann; Kralikova, Eva; Guha, Neela; Minozzi, Silvia; Espina, Carolina; Schüz, Joachim
2015-12-01
Tobacco use, and in particular cigarette smoking, is the single largest preventable cause of cancer in the European Union (EU). All tobacco products contain a wide range of carcinogens. The main cancer-causing agents in tobacco smoke are polycyclic aromatic hydrocarbons, tobacco-specific N-nitrosamines, aromatic amines, aldehydes, and certain volatile organic compounds. Tobacco consumers are also exposed to nicotine, leading to tobacco addiction in many users. Cigarette smoking causes cancer in multiple organs and is the main cause of lung cancer, responsible for approximately 82% of cases. In 2012, about 313,000 new cases of lung cancer and 268,000 lung cancer deaths were reported in the EU; 28% of adults in the EU smoked tobacco, and the overall prevalence of current use of smokeless tobacco products was almost 2%. Smokeless tobacco products, a heterogeneous category, are also carcinogenic but cause a lower burden of cancer deaths than tobacco smoking. One low-nitrosamine product, snus, is associated with much lower cancer risk than other smokeless tobacco products. Smoking generates second-hand smoke (SHS), an established cause of lung cancer, and inhalation of SHS by non-smokers is still common in indoor workplaces as well as indoor public places, and more so in the homes of smokers. Several interventions have proved effective for stopping smoking; the most effective intervention is the use of a combination of pharmacotherapy and behavioural support. Scientific evidence leads to the following two recommendations for individual action on tobacco in the 4th edition of the European Code Against Cancer: (1) "Do not smoke. Do not use any form of tobacco"; (2) "Make your home smoke-free. Support smoke-free policies in your workplace".
High order asymptotic preserving nodal discontinuous Galerkin IMEX schemes for the BGK equation
NASA Astrophysics Data System (ADS)
Xiong, Tao; Jang, Juhi; Li, Fengyan; Qiu, Jing-Mei
2015-03-01
In this paper, we develop high-order asymptotic preserving (AP) schemes for the BGK equation in a hyperbolic scaling, which leads to the macroscopic models such as the Euler and compressible Navier-Stokes equations in the asymptotic limit. Our approaches are based on the so-called micro-macro formulation of the kinetic equation which involves a natural decomposition of the problem to the equilibrium and the non-equilibrium parts. The proposed methods are formulated for the BGK equation with constant or spatially variant Knudsen number. The new ingredients for the proposed methods to achieve high order accuracy are the following: we introduce discontinuous Galerkin (DG) discretization of arbitrary order of accuracy with nodal Lagrangian basis functions in space; we employ a high order globally stiffly accurate implicit-explicit (IMEX) Runge-Kutta (RK) scheme as time discretization. Two versions of the schemes are proposed: Scheme I is a direct formulation based on the micro-macro decomposition of the BGK equation, while Scheme II, motivated by the asymptotic analysis for the continuous problem, utilizes certain properties of the projection operator. Compared with Scheme I, Scheme II not only has better computational efficiency (the computational cost is reduced by half roughly), but also allows the establishment of a formal asymptotic analysis. Specifically, it is demonstrated that when 0 < ε ≪ 1, Scheme II, up to O (ε2), becomes a local DG discretization with an explicit RK method for the macroscopic compressible Navier-Stokes equations, a method in a similar spirit to the ones in Bassi and Rebay (1997) [3], Cockburn and Shu (1998) [16]. Numerical results are presented for a wide range of Knudsen number to illustrate the effectiveness and high order accuracy of the methods.
Overview of the NASA Glenn Flux Reconstruction Based High-Order Unstructured Grid Code
NASA Technical Reports Server (NTRS)
Spiegel, Seth C.; DeBonis, James R.; Huynh, H. T.
2016-01-01
A computational fluid dynamics code based on the flux reconstruction (FR) method is currently being developed at NASA Glenn Research Center to ultimately provide a large- eddy simulation capability that is both accurate and efficient for complex aeropropulsion flows. The FR approach offers a simple and efficient method that is easy to implement and accurate to an arbitrary order on common grid cell geometries. The governing compressible Navier-Stokes equations are discretized in time using various explicit Runge-Kutta schemes, with the default being the 3-stage/3rd-order strong stability preserving scheme. The code is written in modern Fortran (i.e., Fortran 2008) and parallelization is attained through MPI for execution on distributed-memory high-performance computing systems. An h- refinement study of the isentropic Euler vortex problem is able to empirically demonstrate the capability of the FR method to achieve super-accuracy for inviscid flows. Additionally, the code is applied to the Taylor-Green vortex problem, performing numerous implicit large-eddy simulations across a range of grid resolutions and solution orders. The solution found by a pseudo-spectral code is commonly used as a reference solution to this problem, and the FR code is able to reproduce this solution using approximately the same grid resolution. Finally, an examination of the code's performance demonstrates good parallel scaling, as well as an implementation of the FR method with a computational cost/degree- of-freedom/time-step that is essentially independent of the solution order of accuracy for structured geometries.
A laboratory model of post-Newtonian gravity with high power lasers and 4th generation light sources
NASA Astrophysics Data System (ADS)
Gregori, G.; Levy, M. C.; Wadud, M. A.; Crowley, B. J. B.; Bingham, R.
2016-04-01
Using the post-Newtonian formalism of gravity, we attempt to calculate the x-ray Thomson scattering cross section of electrons that are accelerated in the field of a high intensity optical laser. We show that our results are consistent with previous calculations, suggesting that the combination of high power laser and 4th generation light sources may become a powerful platform to test models exploring high order corrections to the Newtonian gravity.
General Chemistry Collection for Students (CD-ROM), Abstract of Special Issue 16, 4th Edition
NASA Astrophysics Data System (ADS)
2000-07-01
bookstore. The cost per CD can be quite low when large numbers are ordered (as little as $3 each), making this a cost-effective method of allowing students access to the software they need whenever and wherever they desire. Other JCE Software CDs can also be adopted. Network licenses to distribute the software to your students via your local campus network can also be arranged. Contact us for details on purchasing multiple user licenses. Price and Ordering An order form is inserted in this issue that provides prices and other ordering information. If this card is not available or if you need additional information, contact: JCE Software, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1396; phone; 608/262-5153 or 800/991-5534; fax: 608/265-8094; email: jcesoft@chem.wisc.edu. Table 1. Contents of the General Chemistry Collection, 4th Edition
NASA Astrophysics Data System (ADS)
Shi, F.; Kirby, J. T.; Tehranirad, B.
2010-12-01
Recent progress in the development of Boussinesq-type wave models using TVD-MUSCL schemes have shown robust performance of the shock-capturing method in simulating breaking waves and coastal inundation (Tonelli and Petti, 2009, Roeber et al., 2010, Shiach and Mingham, 2009, Erduran et al., 2005, and others). Shock-capturing schemes make the treatment of wave breaking straightforward without an artificial viscosity adopted in some breaking wave models such as in Kennedy et al. (2000). The schemes are also able to capture the sharp wave front occurring in the swash zone. A high-order temporal scheme usually requires uniform time-stepping, decreasing model efficiency in applications to breaking waves and inundation where super-critical fluid conditions limit the time step associated with the CFL-criterion. In this presentation, we describe the use of a higher order, adaptive time-stepping algorithm using the Runge-Kutta method in a fully nonlinear Boussinesq wave model. Higher-order numerical schemes in both space and time were applied in order to avoid contamination of the physical dispersive terms in Boussinesq equations resulting from truncation errors in the lower-order (second-order) approximation. The spatial derivatives are discritized using a combination of finite-volume and finite-difference methods. A fourth-order MUSCL reconstruction technique is used in the Riemann solver. The model code is parallelized for the MPI computational environment. We illustrate the model's application to the problems of wave runup and coastal inundation in the context of a standard suite of benchmark tests.
75 FR 35649 - Safety Zone; Northern California Annual Fireworks Events, July 4th Fireworks Display
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-23
... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Northern California Annual Fireworks Events, July 4th Fireworks Display AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement of regulation. SUMMARY: The Coast Guard will enforce the Tahoe City 4th of July Fireworks Display safety zone, from 9 a.m. through 10...
75 FR 26157 - Safety Zone; Reedville July 4th Celebration, Cockrell's Creek, Reedville, VA
Federal Register 2010, 2011, 2012, 2013, 2014
2010-05-11
... Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public meeting. But you may... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Reedville July 4th Celebration, Cockrell's..., VA in support of the Reedville July 4th Celebration event. This action is intended to restrict...
Science Content Courses: Workshop in Food Chemistry for 4th Grade School Teachers
ERIC Educational Resources Information Center
Chaiyapechara, S.; Dong, F. M.
2004-01-01
A science content course in food chemistry was offered as a 4-day summer workshop from 1999 to 2001 to 4th grade school teachers in the Seattle School District. The objectives of the workshop were to increase the teachers' knowledge of food science, to perform simple experiments that could be used in the 4th grade classroom, and to help the…
The school nutrition program's role in weight management of 4th grade elementary students
Technology Transfer Automated Retrieval System (TEKTRAN)
We are attempting to uncover the school nutrition program's role in weight management of 4th grade elementary students. Data was collected within a time frame for the food frequency questionnaire (FFQ) set at two months at the WT Cheney Elementary School and South Wood Elementary for 4th grade stud...
The Effects of Cooperative Learning Strategies on Vocabulary Skills of 4th Grade Students
ERIC Educational Resources Information Center
Bilen, Didem; Tavil, Zekiye Müge
2015-01-01
This study was carried out to investigate the effects of cooperative learning strategies on the vocabulary skills of 4th grade students. The study was also designed to ascertain the attitudes of the students in the experimental group towards cooperative learning. Out of 96 4th grade students enrolled in the private school where the study took…
NASA Astrophysics Data System (ADS)
Caplan, Ronald Meyer
We numerically study the dynamics and interactions of vortex rings in the nonlinear Schrodinger equation (NLSE). Single ring dynamics for both bright and dark vortex rings are explored including their traverse velocity, stability, and perturbations resulting in quadrupole oscillations. Multi-ring dynamics of dark vortex rings are investigated, including scattering and merging of two colliding rings, leapfrogging interactions of co-traveling rings, as well as co-moving steady-state multi-ring ensembles. Simulations of choreographed multi-ring setups are also performed, leading to intriguing interaction dynamics. Due to the inherent lack of a close form solution for vortex rings and the dimensionality where they live, efficient numerical methods to integrate the NLSE have to be developed in order to perform the extensive number of required simulations. To facilitate this, compact high-order numerical schemes for the spatial derivatives are developed which include a new semi-compact modulus-squared Dirichlet boundary condition. The schemes are combined with a fourth-order Runge-Kutta time-stepping scheme in order to keep the overall method fully explicit. To ensure efficient use of the schemes, a stability analysis is performed to find bounds on the largest usable time step-size as a function of the spatial step-size. The numerical methods are implemented into codes which are run on NVIDIA graphic processing unit (GPU) parallel architectures. The codes running on the GPU are shown to be many times faster than their serial counterparts. The codes are developed with future usability in mind, and therefore are written to interface with MATLAB utilizing custom GPU-enabled C codes with a MEX-compiler interface. Reproducibility of results is achieved by combining the codes into a code package called NLSEmagic which is freely distributed on a dedicated website.
NASA Astrophysics Data System (ADS)
Tukaram Aghav, Sandip; Achyut Gangal, Shashikala
2014-06-01
In this paper, the main work is focused on designing and simplifying the orbit determination algorithm which will be used for Low Earth Orbit (LEO) navigation. The various data processing algorithms, state estimation algorithms and modeling forces were studied in detail, and simplified algorithm is selected to reduce hardware burden and computational cost. This is done by using raw navigation solution provided by GPS Navigation sensor. A fixed step-size Runge-Kutta 4th order numerical integration method is selected for orbit propagation. Both, the least square and Extended Kalman Filter (EKF) orbit estimation algorithms are developed and the results of the same are compared with each other. EKF algorithm converges faster than least square algorithm. EKF algorithm satisfies the criterions of low computation burden which is required for autonomous orbit determination. Simple static force models also feasible to reduce the hardware burden and computational cost.
Charged particle tracking at Titan, and further applications
NASA Astrophysics Data System (ADS)
Bebesi, Zsofia; Erdos, Geza; Szego, Karoly
2016-04-01
We use the CAPS ion data of Cassini to investigate the dynamics and origin of Titan's atmospheric ions. We developed a 4th order Runge-Kutta method to calculate particle trajectories in a time reversed scenario. The test particle magnetic field environment imitates the curved magnetic environment in the vicinity of Titan. The minimum variance directions along the S/C trajectory have been calculated for all available Titan flybys, and we assumed a homogeneous field that is perpendicular to the minimum variance direction. Using this method the magnetic field lines have been calculated along the flyby orbits so we could select those observational intervals when Cassini and the upper atmosphere of Titan were magnetically connected. We have also taken the Kronian magnetodisc into consideration, and used different upstream magnetic field approximations depending on whether Titan was located inside of the magnetodisc current sheet, or in the lobe regions. We also discuss the code's applicability to comets.
Physics Computing '92: Proceedings of the 4th International Conference
NASA Astrophysics Data System (ADS)
de Groot, Robert A.; Nadrchal, Jaroslav
1993-04-01
* Ordered Particle Simulations for Serial and MIMD Parallel Computers * "NOLP" -- Program Package for Laser Plasma Nonlinear Optics * Algorithms to Solve Nonlinear Least Square Problems * Distribution of Hydrogen Atoms in Pd-H Computed by Molecular Dynamics * A Ray Tracing of Optical System for Protein Crystallography Beamline at Storage Ring-SIBERIA-2 * Vibrational Properties of a Pseudobinary Linear Chain with Correlated Substitutional Disorder * Application of the Software Package Mathematica in Generalized Master Equation Method * Linelist: An Interactive Program for Analysing Beam-foil Spectra * GROMACS: A Parallel Computer for Molecular Dynamics Simulations * GROMACS Method of Virial Calculation Using a Single Sum * The Interactive Program for the Solution of the Laplace Equation with the Elimination of Singularities for Boundary Functions * Random-Number Generators: Testing Procedures and Comparison of RNG Algorithms * Micro-TOPIC: A Tokamak Plasma Impurities Code * Rotational Molecular Scattering Calculations * Orthonormal Polynomial Method for Calibrating of Cryogenic Temperature Sensors * Frame-based System Representing Basis of Physics * The Role of Massively Data-parallel Computers in Large Scale Molecular Dynamics Simulations * Short-range Molecular Dynamics on a Network of Processors and Workstations * An Algorithm for Higher-order Perturbation Theory in Radiative Transfer Computations * Hydrostochastics: The Master Equation Formulation of Fluid Dynamics * HPP Lattice Gas on Transputers and Networked Workstations * Study on the Hysteresis Cycle Simulation Using Modeling with Different Functions on Intervals * Refined Pruning Techniques for Feed-forward Neural Networks * Random Walk Simulation of the Motion of Transient Charges in Photoconductors * The Optical Hysteresis in Hydrogenated Amorphous Silicon * Diffusion Monte Carlo Analysis of Modern Interatomic Potentials for He * A Parallel Strategy for Molecular Dynamics Simulations of Polar Liquids on
European Code against Cancer 4th Edition: Infections and Cancer.
Villain, Patricia; Gonzalez, Paula; Almonte, Maribel; Franceschi, Silvia; Dillner, Joakim; Anttila, Ahti; Park, Jin Young; De Vuyst, Hugo; Herrero, Rolando
2015-12-01
Of the 2,635,000 new cancer cases (excluding non-melanoma skin cancers) occurring in the European Union (EU) in 2012, it is estimated that approximately 185,000 are related to infection with human papillomaviruses (HPVs), hepatitis B and C viruses (HBV and HCV), and Helicobacter pylori (H. pylori). Chronic infection with these agents can lead to cancers of the cervix uteri, liver, and stomach, respectively. Chronic infection with HCV can also lead to B-cell non-Hodgkin lymphoma. Human immunodeficiency virus (HIV) infection continues to be of major public health importance in several EU countries and increases cancer risk via HIV-induced immunosuppression. The fourth edition of the European Code Against Cancer presents recommendations on effective and safe preventive interventions in order to reduce the risk of infection-related cancers in EU citizens. Based on current available evidence, the fourth edition recommends that parents ensure the participation of their children in vaccination programs against HBV (for newborns) and HPV (for girls). In the 'Questions and Answers' (Q&As) section about vaccination and infections in the website for the European Code Against Cancer, individuals who are at risk of chronic HBV or HCV are advised to seek medical advice about testing and obtaining treatment when appropriate. Individuals most at risk of HIV are advised to consult their doctor or healthcare provider to access counselling and, if needed, testing and treatment without delay. Information about H. pylori testing and treatment is also provided as testing might currently be offered in some high-risk areas in Europe. The rationale and supporting evidence for the recommendations on vaccination in the European Code Against Cancer, and for the main recommendations on vaccination and infection in the Q&As, are explained in the present review. PMID:26589774
European Code against Cancer 4th Edition: Infections and Cancer.
Villain, Patricia; Gonzalez, Paula; Almonte, Maribel; Franceschi, Silvia; Dillner, Joakim; Anttila, Ahti; Park, Jin Young; De Vuyst, Hugo; Herrero, Rolando
2015-12-01
Of the 2,635,000 new cancer cases (excluding non-melanoma skin cancers) occurring in the European Union (EU) in 2012, it is estimated that approximately 185,000 are related to infection with human papillomaviruses (HPVs), hepatitis B and C viruses (HBV and HCV), and Helicobacter pylori (H. pylori). Chronic infection with these agents can lead to cancers of the cervix uteri, liver, and stomach, respectively. Chronic infection with HCV can also lead to B-cell non-Hodgkin lymphoma. Human immunodeficiency virus (HIV) infection continues to be of major public health importance in several EU countries and increases cancer risk via HIV-induced immunosuppression. The fourth edition of the European Code Against Cancer presents recommendations on effective and safe preventive interventions in order to reduce the risk of infection-related cancers in EU citizens. Based on current available evidence, the fourth edition recommends that parents ensure the participation of their children in vaccination programs against HBV (for newborns) and HPV (for girls). In the 'Questions and Answers' (Q&As) section about vaccination and infections in the website for the European Code Against Cancer, individuals who are at risk of chronic HBV or HCV are advised to seek medical advice about testing and obtaining treatment when appropriate. Individuals most at risk of HIV are advised to consult their doctor or healthcare provider to access counselling and, if needed, testing and treatment without delay. Information about H. pylori testing and treatment is also provided as testing might currently be offered in some high-risk areas in Europe. The rationale and supporting evidence for the recommendations on vaccination in the European Code Against Cancer, and for the main recommendations on vaccination and infection in the Q&As, are explained in the present review.
4th floor sacking deck looking east from 1945 elevator to ...
4th floor sacking deck looking east from 1945 elevator to 1913 elevator indicating spout used to load bulk grain into rail cars - Stewart Company Grain Elevator, 16 West Carson Street, Pittsburgh, Allegheny County, PA
16. 4th floor roof, view west, north side of setback ...
16. 4th floor roof, view west, north side of setback to left and delivery stair bulkhead to right - Sheffield Farms Milk Plant, 1075 Webster Avenue (southwest corner of 166th Street), Bronx, Bronx County, NY
TID Test Results for 4th Generation iPad(TradeMark)
NASA Technical Reports Server (NTRS)
Guertin, S. M.; Allen, G. R.; McClure, S. S.; LaBel, K. A.
2013-01-01
TID testing of 4th generation iPads is reported. Of iPad subsystems, results indicate that the charging circuitry and display drivers fail at lowest TID levels. Details of construction are investigated for additional testing of components.
NASA Astrophysics Data System (ADS)
Núñez-de la Rosa, Jonatan; Munz, Claus-Dieter
2016-07-01
In this work, we discuss the extension of the XTROEM-FV code to relativistic hydrodynamics and magnetohydrodynamics. XTROEM-FV is a simulation package for computational astrophysics based on very high order finite-volume methods on Cartesian coordinates. Arbitrary spatial high order of accuracy is achieved with a weighted essentially non-oscillatory (WENO) reconstruction operator, and the time evolution is carried out with a strong stability preserving Runge-Kutta scheme. In XTROEM-FV has been implemented a cheap, robust, and accurate shock-capturing strategy for handling complex shock waves problems, typical in an astrophysical environment. The divergence constraint of the magnetic field is tackled with the generalized Lagrange multiplier divergence cleaning approach. Numerical computations of smooth flows for the relativistic hydrodynamics and magnetohydrodynamics equations are performed and confirm the high-order accuracy of the main reconstruction algorithm for such kind of flows. XTROEM-FV has been subject to a comprehensive numerical benchmark, especially for complex flows configurations within an astrophysical context. Computations of problems with shocks with very high order reconstruction operators up to seventh order are reported. For instance, one-dimensional shock tubes problems for relativistic hydrodynamics and magnetohydrodynamics, as well as two-dimensional flows like the relativistic double Mach reflection problem, the interaction of a shock wave with a bubble, the relativistic Orszag-Tang vortex, the cylindrical blast wave problem, the rotor problem, the Kelvin-Helmholtz instability, and an astrophysical slab jet. XTROEM-FV represents a new attempt to simulate astrophysical flow phenomena with very high order numerical methods.
Physics Computing '92: Proceedings of the 4th International Conference
NASA Astrophysics Data System (ADS)
de Groot, Robert A.; Nadrchal, Jaroslav
1993-04-01
* Ordered Particle Simulations for Serial and MIMD Parallel Computers * "NOLP" -- Program Package for Laser Plasma Nonlinear Optics * Algorithms to Solve Nonlinear Least Square Problems * Distribution of Hydrogen Atoms in Pd-H Computed by Molecular Dynamics * A Ray Tracing of Optical System for Protein Crystallography Beamline at Storage Ring-SIBERIA-2 * Vibrational Properties of a Pseudobinary Linear Chain with Correlated Substitutional Disorder * Application of the Software Package Mathematica in Generalized Master Equation Method * Linelist: An Interactive Program for Analysing Beam-foil Spectra * GROMACS: A Parallel Computer for Molecular Dynamics Simulations * GROMACS Method of Virial Calculation Using a Single Sum * The Interactive Program for the Solution of the Laplace Equation with the Elimination of Singularities for Boundary Functions * Random-Number Generators: Testing Procedures and Comparison of RNG Algorithms * Micro-TOPIC: A Tokamak Plasma Impurities Code * Rotational Molecular Scattering Calculations * Orthonormal Polynomial Method for Calibrating of Cryogenic Temperature Sensors * Frame-based System Representing Basis of Physics * The Role of Massively Data-parallel Computers in Large Scale Molecular Dynamics Simulations * Short-range Molecular Dynamics on a Network of Processors and Workstations * An Algorithm for Higher-order Perturbation Theory in Radiative Transfer Computations * Hydrostochastics: The Master Equation Formulation of Fluid Dynamics * HPP Lattice Gas on Transputers and Networked Workstations * Study on the Hysteresis Cycle Simulation Using Modeling with Different Functions on Intervals * Refined Pruning Techniques for Feed-forward Neural Networks * Random Walk Simulation of the Motion of Transient Charges in Photoconductors * The Optical Hysteresis in Hydrogenated Amorphous Silicon * Diffusion Monte Carlo Analysis of Modern Interatomic Potentials for He * A Parallel Strategy for Molecular Dynamics Simulations of Polar Liquids on
European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer.
McColl, Neil; Auvinen, Anssi; Kesminiene, Ausrele; Espina, Carolina; Erdmann, Friederike; de Vries, Esther; Greinert, Rüdiger; Harrison, John; Schüz, Joachim
2015-12-01
Ionising radiation can transfer sufficient energy to ionise molecules, and this can lead to chemical changes, including DNA damage in cells. Key evidence for the carcinogenicity of ionising radiation comes from: follow-up studies of the survivors of the atomic bombings in Japan; other epidemiological studies of groups that have been exposed to radiation from medical, occupational or environmental sources; experimental animal studies; and studies of cellular responses to radiation. Considering exposure to environmental ionising radiation, inhalation of naturally occurring radon is the major source of radiation in the population - in doses orders of magnitude higher than those from nuclear power production or nuclear fallout. Indoor exposure to radon and its decay products is an important cause of lung cancer; radon may cause approximately one in ten lung cancers in Europe. Exposures to radon in buildings can be reduced via a three-step process of identifying those with potentially elevated radon levels, measuring radon levels, and reducing exposure by installation of remediation systems. In the 4th Edition of the European Code against Cancer it is therefore recommended to: "Find out if you are exposed to radiation from naturally high radon levels in your home. Take action to reduce high radon levels". Non-ionising types of radiation (those with insufficient energy to ionise molecules) - including extremely low-frequency electric and magnetic fields as well as radiofrequency electromagnetic fields - are not an established cause of cancer and are therefore not addressed in the recommendations to reduce cancer risk. PMID:26126928
European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer.
McColl, Neil; Auvinen, Anssi; Kesminiene, Ausrele; Espina, Carolina; Erdmann, Friederike; de Vries, Esther; Greinert, Rüdiger; Harrison, John; Schüz, Joachim
2015-12-01
Ionising radiation can transfer sufficient energy to ionise molecules, and this can lead to chemical changes, including DNA damage in cells. Key evidence for the carcinogenicity of ionising radiation comes from: follow-up studies of the survivors of the atomic bombings in Japan; other epidemiological studies of groups that have been exposed to radiation from medical, occupational or environmental sources; experimental animal studies; and studies of cellular responses to radiation. Considering exposure to environmental ionising radiation, inhalation of naturally occurring radon is the major source of radiation in the population - in doses orders of magnitude higher than those from nuclear power production or nuclear fallout. Indoor exposure to radon and its decay products is an important cause of lung cancer; radon may cause approximately one in ten lung cancers in Europe. Exposures to radon in buildings can be reduced via a three-step process of identifying those with potentially elevated radon levels, measuring radon levels, and reducing exposure by installation of remediation systems. In the 4th Edition of the European Code against Cancer it is therefore recommended to: "Find out if you are exposed to radiation from naturally high radon levels in your home. Take action to reduce high radon levels". Non-ionising types of radiation (those with insufficient energy to ionise molecules) - including extremely low-frequency electric and magnetic fields as well as radiofrequency electromagnetic fields - are not an established cause of cancer and are therefore not addressed in the recommendations to reduce cancer risk.
75 FR 38721 - Safety Zone; Munising 4th of July Fireworks, South Bay, Lake Superior, Munising, MI
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-06
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Munising 4th of July Fireworks, South Bay... is intended to restrict vessels from a portion of South Bay during the Munising 4th of July Fireworks... from hazards associated with the Munising 4th of July Fireworks display. Based on the explosive...
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-17
... Chicago's July 4th Celebration Fireworks, Chicago, Illinois in the Federal Register (75 FR 22330). We... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zones; City of Chicago's July 4th Celebration... associated with the City of Chicago's July 4th Celebration Fireworks. The Captain of the Port, Sector...
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-06
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Sault Sainte Marie 4th of July Fireworks... the Sault Sainte Marie 4th of July Fireworks display, July ] 4, 2010. This temporary safety zone is... with the Sault Sainte Marie 4th of July Fireworks display. The fireworks display is planned to...
Collaborative study for the establishment of the 4(th) International Standard for Streptomycin.
Jorajuria, S; Raphalen, C; Dujardin, V; Daas, A
2015-01-01
An international collaborative study was organised to establish the 4(th) World Health Organization (WHO) International Standard (IS) for Streptomycin. Fourteen laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 3(rd) IS for Streptomycin was used as a reference. Based on the results of the study, the 4(th) IS for Streptomycin was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2015 with an assigned potency of 76 000 International Units (IU) per vial. The 4(th) IS for Streptomycin is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).
European Code against Cancer 4th Edition: Environment, occupation and cancer.
Espina, Carolina; Straif, Kurt; Friis, Søren; Kogevinas, Manolis; Saracci, Rodolfo; Vainio, Harri; Schüz, Joachim
2015-12-01
People are exposed throughout life to a wide range of environmental and occupational pollutants from different sources at home, in the workplace or in the general environment - exposures that normally cannot be directly controlled by the individual. Several chemicals, metals, dusts, fibres, and occupations have been established to be causally associated with an increased risk of specific cancers, such as cancers of the lung, skin and urinary bladder, and mesothelioma. Significant amounts of air pollutants - mainly from road transport and industry - continue to be emitted in the European Union (EU); an increased occurrence of lung cancer has been attributed to air pollution even in areas below the EU limits for daily air pollution. Additionally, a wide range of pesticides as well as industrial and household chemicals may lead to widespread human exposure, mainly through food and water. For most environmental pollutants, the most effective measures are regulations and community actions aimed at reducing and eliminating the exposures. Thus, it is imperative to raise awareness about environmental and occupational carcinogens in order to motivate individuals to be proactive in advocating protection and supporting initiatives aimed at reducing pollution. Regulations are not homogeneous across EU countries, and protective measures in the workplace are not used consistently by all workers all the time; compliance with regulations needs to be continuously monitored and enforced. Therefore, the recommendation on Environment and Occupation of the 4th edition of the European Code against Cancer, focusing on what individuals can do to reduce their cancer risk, reads: "In the workplace, protect yourself against cancer-causing substances by following health and safety instructions."
European Code against Cancer 4th Edition: Environment, occupation and cancer.
Espina, Carolina; Straif, Kurt; Friis, Søren; Kogevinas, Manolis; Saracci, Rodolfo; Vainio, Harri; Schüz, Joachim
2015-12-01
People are exposed throughout life to a wide range of environmental and occupational pollutants from different sources at home, in the workplace or in the general environment - exposures that normally cannot be directly controlled by the individual. Several chemicals, metals, dusts, fibres, and occupations have been established to be causally associated with an increased risk of specific cancers, such as cancers of the lung, skin and urinary bladder, and mesothelioma. Significant amounts of air pollutants - mainly from road transport and industry - continue to be emitted in the European Union (EU); an increased occurrence of lung cancer has been attributed to air pollution even in areas below the EU limits for daily air pollution. Additionally, a wide range of pesticides as well as industrial and household chemicals may lead to widespread human exposure, mainly through food and water. For most environmental pollutants, the most effective measures are regulations and community actions aimed at reducing and eliminating the exposures. Thus, it is imperative to raise awareness about environmental and occupational carcinogens in order to motivate individuals to be proactive in advocating protection and supporting initiatives aimed at reducing pollution. Regulations are not homogeneous across EU countries, and protective measures in the workplace are not used consistently by all workers all the time; compliance with regulations needs to be continuously monitored and enforced. Therefore, the recommendation on Environment and Occupation of the 4th edition of the European Code against Cancer, focusing on what individuals can do to reduce their cancer risk, reads: "In the workplace, protect yourself against cancer-causing substances by following health and safety instructions." PMID:26164655
Minozzi, Silvia; Armaroli, Paola; Espina, Carolina; Villain, Patricia; Wiseman, Martin; Schüz, Joachim; Segnan, Nereo
2015-12-01
The European Code Against Cancer is a set of recommendations to give advice on cancer prevention. Its 4th edition is an update of the 3rd edition, from 2003. Working Groups of independent experts from different fields of cancer prevention were appointed to review the recommendations, supported by a Literature Group to provide scientific and technical support in the assessment of the scientific evidence, through systematic reviews of the literature. Common procedures were developed to guide the experts in identifying, retrieving, assessing, interpreting and summarizing the scientific evidence in order to revise the recommendations. The Code strictly followed the concept of providing advice to European Union citizens based on the current best available science. The advice, if followed, would be expected to reduce cancer risk, referring both to avoiding or reducing exposure to carcinogenic agents or changing behaviour related to cancer risk and to participating in medical interventions able to avert specific cancers or their consequences. The information sources and procedures for the review of the scientific evidence are described here in detail. The 12 recommendations of the 4th edition of the European Code Against Cancer were ultimately approved by a Scientific Committee of leading European cancer and public health experts.
33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.
Code of Federal Regulations, 2010 CFR
2010-07-01
... CFR 165.23 apply. (2) No vessels, except the Staten Island Ferries, will be allowed to transit the... Fireworks, East River, NY. 165.166 Section 165.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.166 Safety Zone: Macy's July 4th Fireworks, East River, NY. (a) Regulated area. The following...
33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.
Code of Federal Regulations, 2014 CFR
2014-07-01
... CFR 165.23 apply. (2) No vessels, except the Staten Island Ferries, will be allowed to transit the... Fireworks, East River, NY. 165.166 Section 165.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.166 Safety Zone: Macy's July 4th Fireworks, East River, NY. (a) Regulated area. The following...
33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.
Code of Federal Regulations, 2013 CFR
2013-07-01
... CFR 165.23 apply. (2) No vessels, except the Staten Island Ferries, will be allowed to transit the... Fireworks, East River, NY. 165.166 Section 165.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.166 Safety Zone: Macy's July 4th Fireworks, East River, NY. (a) Regulated area. The following...
33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.
Code of Federal Regulations, 2011 CFR
2011-07-01
... CFR 165.23 apply. (2) No vessels, except the Staten Island Ferries, will be allowed to transit the... Fireworks, East River, NY. 165.166 Section 165.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.166 Safety Zone: Macy's July 4th Fireworks, East River, NY. (a) Regulated area. The following...
33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.
Code of Federal Regulations, 2012 CFR
2012-07-01
... CFR 165.23 apply. (2) No vessels, except the Staten Island Ferries, will be allowed to transit the... Fireworks, East River, NY. 165.166 Section 165.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.166 Safety Zone: Macy's July 4th Fireworks, East River, NY. (a) Regulated area. The following...
75 FR 34639 - Safety Zone; Reedville July 4th Celebration, Cockrell's Creek, Reedville, VA
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-18
... the Reedville July 4th Celebration event. This action is intended to restrict vessel traffic movement... Celebration, Cockrell's Creek, Reedville, VA in the Federal Register (75 FR 26157). We received no comments on... standards bodies. This rule does not use technical standards. Therefore, we did not consider the use...
4th level of 1913 elevator indicating sacking scale, part of ...
4th level of 1913 elevator indicating sacking scale, part of the bagging system and nate to the sewing machine. Discharge spout for the grain bin to the left - Stewart Company Grain Elevator, 16 West Carson Street, Pittsburgh, Allegheny County, PA
4th level of 1945 warehouse indicating drag conveyor. From here ...
4th level of 1945 warehouse indicating drag conveyor. From here screenings were pumped from the elevator leg to this conveyor. The grains were ground, then conveyed back down to the first floor for bagging. - Stewart Company Grain Elevator, 16 West Carson Street, Pittsburgh, Allegheny County, PA
ERIC Educational Resources Information Center
Lynott, Patricia P.; Merola, Pamela R.
2007-01-01
The purpose of this study was to examine the effects of an intergenerational program on children's attitudes toward older people. Four 4th grade classes, one each during the years 2002 through 2005, participated in the study. The elders and school children engaged in meaningful activities over a 5 month period, including the performance of a play…
Reading Development and Achievement of 4th-Grade Hmong Students
ERIC Educational Resources Information Center
Mahowald, Megan; Loughnane, Megan
2016-01-01
Researchers and practitioners alike have noted that Hmong students in the United States do not achieve as well as their monolingual peers and other bilingual students. The current mixed-methods study is designed to describe reading development and achievement of 4th-grade Hmong students in one large, urban school district. This study explores the…
15. Old Bergen tunnel, west end, showing proposed 4th track ...
15. Old Bergen tunnel, west end, showing proposed 4th track of Delaware, Lackawanna and Western Railroad and amount of west end of tunnel to be taken out to allow for same, taken August 13, 1906 - Erie Railway, Bergen Hill Open Cut, Palisade Avenue to Tonnele Avenue, Jersey City, Hudson County, NJ
11. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO NORTHEAST, ...
11. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO NORTHEAST, WITH WRAPPER (LEFT), PRESS (CENTER), AND CUTTER (RIGHT, BEHIND CHUTE); BUCKET CONVEYOR AT RIGHT MOVED WASTE FROM PRESS TO 5TH FLOOR FOR RE-MANUFACTURE - Colgate & Company Jersey City Plant, Building No. B-14, 54-58 Grand Street, Jersey City, Hudson County, NJ
77 FR 56208 - Filing Dates for the Kentucky Special Election in the 4th Congressional District
Federal Register 2010, 2011, 2012, 2013, 2014
2012-09-12
... From the Federal Register Online via the Government Publishing Office FEDERAL ELECTION COMMISSION Filing Dates for the Kentucky Special Election in the 4th Congressional District AGENCY: Federal Election Commission. ACTION: Notice of filing dates for special election. SUMMARY: Kentucky has scheduled a...
77 FR 39408 - Safety Zone; Buffalo July 4th Fireworks, Lake Erie, Buffalo, NY
Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-03
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Buffalo July 4th Fireworks, Lake Erie, Buffalo, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on Lake Erie, Buffalo, NY. This safety zone is intended to...
20. TYPICAL VIEW OF FRONT WINDOWS FROM 4TH TO 9TH ...
20. TYPICAL VIEW OF FRONT WINDOWS FROM 4TH TO 9TH FLOOR WITH WHITE GLAZED TERRA COTTA SILL AND HEADERS. MULLIONS ARE ORANGE BROWN BRICKS LIKE THE WALLS. BRICKS ARE IN FLEMISH BOND PATTERN. - Pacific Telephone & Telegraph Company Building, 1519 Franklin Street, Oakland, Alameda County, CA
MAIN GATE, INTERSECTION OF 4TH AVE (200 NORTH) AND N ...
MAIN GATE, INTERSECTION OF 4TH AVE (200 NORTH) AND N STREET (895 EAST), SALT LAKE CITY, UT. VIEW LOOKING EAST THROUGH MAIN CEMETERY GATE TO CEMETERY'S MAIN STREET, REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 18276, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT
Assessment of an Engineering Technology Outreach Program for 4th-7th Grade Girls
ERIC Educational Resources Information Center
Dell, Elizabeth M.; Christman, Jeanne; Garrick, Robert D.
2011-01-01
This paper describes a workshop led by female Engineering Technology students, with support from female faculty, to provide an introduction to Engineering Technology to 4th-7th grade girls through a series of interactive laboratory experiments. This outreach program was developed to improve attitudes towards science and engineering in middle…
NASA Astrophysics Data System (ADS)
Graham Hoover, William; Clinton Sprott, Julien; Griswold Hoover, Carol
2016-10-01
We describe the application of adaptive (variable time step) integrators to stiff differential equations encountered in many applications. Linear harmonic oscillators subject to nonlinear thermal constraints can exhibit either stiff or smooth dynamics. Two closely related examples, Nosé's dynamics and Nosé-Hoover dynamics, are both based on Hamiltonian mechanics and generate microstates consistent with Gibbs' canonical ensemble. Nosé's dynamics is stiff and can present severe numerical difficulties. Nosé-Hoover dynamics, although it follows exactly the same trajectory, is smooth and relatively trouble-free. We emphasize the power of adaptive integrators to resolve stiff problems such as the Nosé dynamics for the harmonic oscillator. The solutions also illustrate the power of computer graphics to enrich numerical solutions.
High Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration
NASA Technical Reports Server (NTRS)
Scott, James R.; Martini, Michael C.
2008-01-01
Taylor series integration is implemented in a spacecraft trajectory analysis code-the Spacecraft N-body Analysis Program (SNAP) - and compared with the code s existing eighth-order Runge-Kutta Fehlberg time integration scheme. Nine trajectory problems, including near Earth, lunar, Mars and Europa missions, are analyzed. Head-to-head comparison at five different error tolerances shows that, on average, Taylor series is faster than Runge-Kutta Fehlberg by a factor of 15.8. Results further show that Taylor series has superior convergence properties. Taylor series integration proves that it can provide rapid, highly accurate solutions to spacecraft trajectory problems.
Numerical solution for weight reduction model due to health campaigns in Spain
NASA Astrophysics Data System (ADS)
Mohammed, Maha A.; Noor, Noor Fadiya Mohd; Siri, Zailan; Ibrahim, Adriana Irawati Nur
2015-10-01
Transition model between three subpopulations based on Body Mass Index of Valencia community in Spain is considered. No changes in population nutritional habits and public health strategies on weight reduction until 2030 are assumed. The system of ordinary differential equations is solved using Runge-Kutta method of higher order. The numerical results obtained are compared with the predicted values of subpopulation proportion based on statistical estimation in 2013, 2015 and 2030. Relative approximate error is calculated. The consistency of the Runge-Kutta method in solving the model is discussed.
Critical study of observation of the sternal end of the right 4th rib.
Fanton, Laurent; Gustin, Marie-Paule; Paultre, Ulysse; Schrag, Bettina; Malicier, Daniel
2010-03-01
Studies of the method of estimating age at death by the 4th rib exclusively concerned the phase method without fundamentally challenging the method as such. The present study analyzed observation of the variables on which the Işcan method is based. Ten observers made two assessments of the stage of pit depth, pit shape, rim and wall configurations of 59 right 4th ribs harvested from males (mean age: 49 years; range: 47-94 years). Observation showed poor reproducibility and repeatability for all three variables (Wilcoxon test, kappa-coefficient). Analysis of problem ribs revealed difficulty in measuring and imprecision in describing pit depth and failure to take account of continual aging for the other two variables. Despite these results, Işcan's variables provide objective information on age at death. It is recommended that the method be improved by better description of the variables and use of multivariate statistical analysis.
11(th) National Meeting of Organic Chemistry and 4(th) Meeting of Therapeutic Chemistry.
Sousa, Maria Emília; Araújo, Maria João; do Vale, Maria Luísa; Andrade, Paula B; Branco, Paula; Gomes, Paula; Moreira, Rui; Pinho E Melo, Teresa M V D; Freitas, Victor
2016-03-17
For the first time under the auspices of Sociedade Portuguesa de Química, the competences of two important fields of Chemistry are brought together into a single event, the 11st National Organic Chemistry Meeting and the the 4th National Medicinal Chemistry Meeting, to highlight complementarities and to promote new synergies. Abstracts of plenary lectures, oral communications, and posters presented during the meeting are collected in this report.
10. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO SOUTHWEST, ...
10. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO SOUTHWEST, WITH AUTOMATIC CUTTER (LEFT), PRESS (CENTER), AND WRAPPER (RIGHT); LARGE CHUTE AT CENTER FROM 5TH FLOOR BINS TO 3RD FLOOR SOAP MILLS; OVERHEAD AND FLOOR (LOWER RIGHT) FINISHED GOODS CONVEYORS TO G BLOCK (HAER NO. NJ-71-NN) - Colgate & Company Jersey City Plant, Building No. B-14, 54-58 Grand Street, Jersey City, Hudson County, NJ
11(th) National Meeting of Organic Chemistry and 4(th) Meeting of Therapeutic Chemistry.
Sousa, Maria Emília; Araújo, Maria João; do Vale, Maria Luísa; Andrade, Paula B; Branco, Paula; Gomes, Paula; Moreira, Rui; Pinho E Melo, Teresa M V D; Freitas, Victor
2016-01-01
For the first time under the auspices of Sociedade Portuguesa de Química, the competences of two important fields of Chemistry are brought together into a single event, the 11st National Organic Chemistry Meeting and the the 4th National Medicinal Chemistry Meeting, to highlight complementarities and to promote new synergies. Abstracts of plenary lectures, oral communications, and posters presented during the meeting are collected in this report. PMID:27102166
11th National Meeting of Organic Chemistry and 4th Meeting of Therapeutic Chemistry
Sousa, Maria Emília; Araújo, Maria João; do Vale, Maria Luísa; Andrade, Paula B.; Branco, Paula; Gomes, Paula; Moreira, Rui; Pinho e Melo, Teresa M.V.D.; Freitas, Victor
2016-01-01
For the first time under the auspices of Sociedade Portuguesa de Química, the competences of two important fields of Chemistry are brought together into a single event, the 11st National Organic Chemistry Meeting and the the 4th National Medicinal Chemistry Meeting, to highlight complementarities and to promote new synergies. Abstracts of plenary lectures, oral communications, and posters presented during the meeting are collected in this report. PMID:27102166
A prospective controlled trial of teaching basic surgical skills with 4th year medical students.
Lossing, A; Groetzsch, G
1992-01-01
Scrubbing, gowning, gloving and aseptic technique are currently the only formal teaching 4th year medical students receive at the beginning of an 8-week surgery rotation. Teaching is often delegated to junior house staff and early bad habits are difficult to unlearn in post-graduate training. A study population of 4th year medical students from three hospitals were examined. At the beginning of an 8-week surgery rotation technical skills were tested with a simulation appendectomy model at the beginning and end of the surgery rotation. On day one, after a pre-test, a teaching intervention was alternated between two hospitals. A control group received only a post-test. The outcome measure was a cumulative score of the students' performance in technical stations in the simulation model. A comparison was made of the mean post-test scores in the teaching, non-teaching and control groups. An analysis of variance of all post-test scores rejected the null hypothesis at the 0.05 level. Duncan's multiple range test demonstrated a significant difference between the teaching and non-teaching group. Feedback from 25 students indicated the teaching model was practical and relevant. A formal teaching intervention of basic technical skills with 4th year medical students improved their performance on a simulated appendectomy model.
Large eddy simulation of supersonic twin-jet impingement using a fifth-order WENO scheme
NASA Astrophysics Data System (ADS)
Toh, Hoong Thiam
A three-dimensional flow field produced by supersonic twin-jet impingement is studied using a large eddy simulation (LES). The numerical model consists of two parallel axisymmetric jets of diameter D*, 3 D* apart, issuing from a plane which is at a distance H* = 4D* above the ground. The jet diameter D*, mean velocity W*o , mean density r*o and mean temperature T*o at the jet center in the exit plane are used as reference values. The Mach number and Reynolds number of the jets are M = 1.5 and Re = 5.5 x 105, respectively. This model is closely related to the experimental setup of Elavarasan et al. [23]. The three-dimensional time-dependent compressible Navier-Stokes equations are solved using the method of lines. The convective terms are discretized using a fifth-order WENO scheme, whereas the viscous terms are discretized using a fourth-order central-differencing scheme. A low-storage five-stage fourth-order Runge-Kutta scheme is used to advance the solution in time. Code verification is achieved by comparison with flat-plate boundary-layer linear stability analysis, and computational data by Bendiks et al. [5] for a compressible turbulent round jet. Instantaneous flow, mean flow and Reynolds stresses for the twin-jet impingement are presented and discussed. The results reveal the existence of flapping behavior in the fountain. The flapping fountain is the vortical structure formed by the alternating merging of a primary vortex tube with a secondary vortex tube induced by the neighboring primary vortex tube. The nondimensional period of flapping is found to be 7D*/ W*o . High unsteadiness and strong interaction between the fountain and the jets are also observed. Due to the high diffusion and spreading rate of the fountain, the interaction between the fountain and the jets is only significant up to a height which is less than 3D*. It is found that the mean peak velocity in the fountain is 0.40406 W*o and it occurs at 0.536607D* from the ground. The suitability of
NASA Technical Reports Server (NTRS)
Krishen, Kumar (Editor); Burnham, Calvin (Editor)
1995-01-01
This document contains papers presented at the 4th International Conference Exhibition: World Congress on Superconductivity held June 27-July 1, 1994 in Orlando, Florida. These documents encompass research, technology, applications, funding, political, and social aspects of superconductivity. The areas covered included: high-temperature materials; thin films; C-60 based superconductors; persistent magnetic fields and shielding; fabrication methodology; space applications; physical applications; performance characterization; device applications; weak link effects and flux motion; accelerator technology; superconductivity energy; storage; future research and development directions; medical applications; granular superconductors; wire fabrication technology; computer applications; technical and commercial challenges; and power and energy applications.
NASA Technical Reports Server (NTRS)
Krishen, Kumar (Editor); Burnham, Calvin (Editor)
1995-01-01
The papers presented at the 4th International Conference Exhibition: World Congress on Superconductivity held at the Marriott Orlando World Center, Orlando, Florida, are contained in this document and encompass the research, technology, applications, funding, political, and social aspects of superconductivity. Specifically, the areas covered included: high-temperature materials; thin films; C-60 based superconductors; persistent magnetic fields and shielding; fabrication methodology; space applications; physical applications; performance characterization; device applications; weak link effects and flux motion; accelerator technology; superconductivity energy; storage; future research and development directions; medical applications; granular superconductors; wire fabrication technology; computer applications; technical and commercial challenges, and power and energy applications.
[Global Health. Information for change. 4th report of the Italian Observatory on Global Health].
2011-01-01
Global Health. Information for change. 4th report of the Italian Observatory on Global Health. InformAzione (InformAction) is the title of the last OISG report (Italian observatory on Global Health), dedicated to information and education, the essential bases for a conscious action aimed at decreasing inequalities. Increasing the investments in information, education and interventions oriented to global health may broaden the number of aware and informed citizens, able to start a dialogue, to make pressures to increase the interventions in favor of those in need.
Proceedings of the 4th International Workshop on Tritium Effects in Plasma Facing Components
R. A. Causey
1999-02-01
The 4th International Workshop on Tritium Effects in Plasma Facing Components was held in Santa Fe, New Mexico on May 14-15, 1998. This workshop occurs every two years, and has previously been held in Livermore/California, Nagoya/Japan, and the JRC-Ispra Site in Italy. The purpose of the workshop is to gather researchers involved in the topic of tritium migration, retention, and recycling in materials used to line magnetic fusion reactor walls and provide a forum for presentation and discussions in this area. This document provides an overall summary of the workshop, the workshop agenda, a summary of the presentations, and a list of attendees.
PREFACE: The 4th Symposium on the Mechanics of Slender Structures (MoSS2013)
NASA Astrophysics Data System (ADS)
Cao, Dengqing; Kaczmarczyk, Stefan
2013-07-01
This volume of Journal of Physics: Conference Series contains papers presented at the 4th Symposium on the Mechanics of Slender Structures (MoSS2013) run under the auspices of the Institute of Physics Applied Mechanics Group and hosted by Harbin Institute of Technology (China) from 7-9 January 2013. The conference has been organized in collaboration with the Technical Committee on Vibration and Sound of the American Society of Mechanical Engineers and follows a one day seminar on Ropes, Cables, Belts and Chains: Theory and Applications and the MoSS2006 symposium held at the University of Northampton (UK) in 2004 and 2006, respectively, the MoSS2008 symposium held at the University of Maryland Baltimore County (USA) in 2008 and the MoSS2010 symposium hosted by Mondragon University and held in San Sebastian (Spain) in 2010. The remit of the Symposium on the Mechanics of Slender Structures series involves a broad range of scientific areas. Applications of slender structures include terrestrial, marine and space systems. Moving elastic elements such as ropes, cables, belts and tethers are pivotal components of many engineering systems. Their lengths often vary when the system is in operation. The applications include vertical transportation installations and, more recently, space tether propulsion systems. Traction drive elevator installations employ ropes and belts of variable length as a means of suspension, and also for the compensation of tensile forces over the traction sheave. In cranes and mine hoists, cables and ropes are subject to length variation in order to carry payloads. Tethers experiencing extension and retraction are important components of offshore and marine installations, as well as being proposed for a variety of different space vehicle propulsion systems based on different applications of momentum exchange and electrodynamic interactions with planetary magnetic fields. Furthermore, cables and slender rods are used extensively in civil engineering
Convergence analysis of combinations of different methods
Kang, Y.
1994-12-31
This paper provides a convergence analysis for combinations of different numerical methods for solving systems of differential equations. The author proves that combinations of two convergent linear multistep methods or Runge-Kutta methods produce a new convergent method of which the order is equal to the smaller order of the two original methods.
The use of staggered scheme and an absorbing buffer zone for computational aeroacoustics
NASA Technical Reports Server (NTRS)
Nark, Douglas M.
1995-01-01
Various problems from those proposed for the Computational Aeroacoustics (CAA) workshop were studied using second and fourth order staggered spatial discretizations in conjunction with fourth order Runge-Kutta time integration. In addition, an absorbing buffer zone was used at the outflow boundaries. Promising results were obtained and provide a basis for application of these techniques to a wider variety of problems.
A 3D High-Order Unstructured Finite-Volume Algorithm for Solving Maxwell's Equations
NASA Technical Reports Server (NTRS)
Liu, Yen; Kwak, Dochan (Technical Monitor)
1995-01-01
matching scheme is employed at material interfaces and the Engquist-Majda non-reflecting boundary condition is implemented at the numerical outer boundaries. The staggered leapfrog scheme and the Runge-Kutta methods are utilized for the time integration. Excellent agreements are found between the numerical and analytical solutions.
Spiritual Health Scale 2011: Defining and Measuring 4th Dimension of Health
Dhar, Neera; Chaturvedi, SK; Nandan, Deoki
2011-01-01
In the midst of physical comforts provided by the unprecedented developments in all spheres of life, the humanity is at cross roads and looking at something beyond these means. Spirituality has now been identified globally as an important aspect for providing answers to many questions related to health and happiness. The World Health Organization is also keen at looking beyond physical, mental and social dimensions of the health, and the member countries are actively exploring the 4th Dimension of the health i.e. the spiritual health and its impact on the overall health and happiness of an individual. National Institute of Health and Family Welfare (NIHFW), realized this need and initiated a research study in this direction. In this study, an effort was made to define this 4th Dimension of health from a common worldly person's perspective and measure it. 3 Domains, 6 Constructs and 27 Determinants of spiritual health were identified through a scientific process. A statistically reliable and valid Spiritual Health Scale (SHS 2011) containing 114 items has been developed. Construct validity and test- retest reliability has been established for urban educated adult population. The scale is first of its kind in the world to measure the spiritual health of a common worldly person, which is devoid of religious and cultural bias. Its items have universal applicability. PMID:22279257
PREFACE: 4th International Conference on Mathematical Modeling in Physical Sciences (IC-MSquare2015)
NASA Astrophysics Data System (ADS)
Vlachos, Dimitrios; Vagenas, Elias C.
2015-09-01
The 4th International Conference on Mathematical Modeling in Physical Sciences (IC-MSQUARE) took place in Mykonos, Greece, from Friday 5th June to Monday 8th June 2015. The Conference was attended by more than 150 participants and hosted about 200 oral, poster, and virtual presentations. There were more than 600 pre-registered authors. The 4th IC-MSQUARE consisted of different and diverging workshops and thus covered various research fields where Mathematical Modeling is used, such as Theoretical/Mathematical Physics, Neutrino Physics, Non-Integrable Systems, Dynamical Systems, Computational Nanoscience, Biological Physics, Computational Biomechanics, Complex Networks, Stochastic Modeling, Fractional Statistics, DNA Dynamics, Macroeconomics etc. The scientific program was rather intense as after the Keynote and Invited Talks in the morning, three parallel oral and one poster session were running every day. However, according to all attendees, the program was excellent with a high quality of talks creating an innovative and productive scientific environment for all attendees. We would like to thank the Keynote Speaker and the Invited Speakers for their significant contribution to IC-MSQUARE. We also would like to thank the Members of the International Advisory and Scientific Committees as well as the Members of the Organizing Committee.
Design of a Nb3Sn Magnet for a 4th Generation ECR Ion Source
Prestemon, S,; Trillaud, F.; Caspi, S.; Ferracin, P.; Sabbi, G. L.; Lyneis, C. M.; Leitner, D.; Todd, D. S.; Hafalia, R.
2008-08-17
The next generation of Electron Cyclotron Resonant (ECR) ion sources are expected to operate at a heating radio frequency greater than 40 GHz. The existing 3rd generation systems, exemplified by the state of the art system VENUS, operate in the 10-28 GHz range, and use NbTi superconductors for the confinement coils. The magnetic field needed to confine the plasma scales with the rf frequency, resulting in peak fields on the magnets of the 4th generation system in excess of 10 T. High field superconductors such as Nb{sub 3}Sn must therefore be considered. The magnetic design of a 4th. generation ECR ion source operating at an rf frequency of 56 GHz is considered. The analysis considers both internal and external sextupole configurations, assuming commercially available Nb{sub 3}Sn material properties. Preliminary structural design issues are discussed based on the forces and margins associated with the coils in the different configurations, leading to quantitative data for the determination of a final magnet design.
NASA Astrophysics Data System (ADS)
Hejranfar, Kazem; Ezzatneshan, Eslam
2014-06-01
In this work, the implementation of a high-order compact finite-difference lattice Boltzmann method (CFDLBM) is performed in the generalized curvilinear coordinates to improve the computational efficiency of the solution algorithm to handle curved geometries with non-uniform grids. The incompressible form of the discrete Boltzmann equation with the Bhatnagar-Gross-Krook (BGK) approximation with the pressure as the independent dynamic variable is transformed into the generalized curvilinear coordinates. Herein, the spatial derivatives in the resulting lattice Boltzmann (LB) equation in the computational plane are discretized by using the fourth-order compact finite-difference scheme and the temporal term is discretized with the fourth-order Runge-Kutta scheme to provide an accurate and efficient incompressible flow solver. A high-order spectral-type low-pass compact filter is used to regularize the numerical solution and remove spurious waves generated by boundary conditions, flow non-linearities and grid non-uniformity. All boundary conditions are implemented based on the solution of governing equations in the generalized curvilinear coordinates. The accuracy and efficiency of the solution methodology presented are demonstrated by computing different benchmark steady and unsteady incompressible flow problems. A sensitivity study is also conducted to evaluate the effects of grid size and filtering on the accuracy and convergence rate of the solution. Four test cases considered herein for validating the present computations and demonstrating the accuracy and robustness of the solution algorithm are: unsteady Couette flow and steady flow in a 2-D cavity with non-uniform grid and steady and unsteady flows over a circular cylinder and the NACA0012 hydrofoil at different flow conditions. Results obtained for the above test cases are in good agreement with the existing numerical and experimental results. The study shows the present solution methodology based on the
NASA Technical Reports Server (NTRS)
Freed, Alan D.
1996-01-01
There are many aspects to consider when designing a Rosenbrock-Wanner-Wolfbrandt (ROW) method for the numerical integration of ordinary differential equations (ODE's) solving initial value problems (IVP's). The process can be simplified by constructing ROW methods around good Runge-Kutta (RK) methods. The formulation of a new, simple, embedded, third-order, ROW method demonstrates this design approach.
[Giant cell tumor of the 4th metacarpal bone of the left hand. Apropos of a case].
Kamel, E J; Pinto, J A; Potenza, L; Michelena, A; Perez Signini, F; Fuenmayor, A
1983-01-01
He is a 46 year old patient that consults on a tumor that deforms the back of his left hand. The X-ray examination shows a bone osteolytic tumor with complete dis appearance of the 4th metacarpal. Surgical removal of the tumor was practiced with immediate reconstruction of the 4th metacarpal by an oseo-iliac graft. Anatomopathological examination. It is an ovoid tumor 6.5 long and irregular surface.
Beyond the genomics blueprint: the 4th Human Variome Project Meeting, UNESCO, Paris, 2012.
Kohonen-Corish, Maija R J; Smith, Timothy D; Robinson, Helen M
2013-07-01
The 4th Biennial Meeting of the Human Variome Project Consortium was held at the headquarters of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in Paris, 11-15 June 2012. The Human Variome Project, a nongovernmental organization and an official partner of UNESCO, enables the routine collection, curation, interpretation, and sharing of information on all human genetic variation. This meeting was attended by more than 180 delegates from 39 countries and continued the theme of addressing issues of implementation in this unique project. The meeting was structured around the four main themes of the Human Variome Project strategic plan, "Project Roadmap 2012-2016": setting normative function, behaving ethically, sharing knowledge, and building capacity. During the meeting, the members held extensive discussions to formulate an action plan in the key areas of the Human Variome Project. The actions agreed on were promulgated at the Project's two Advisory Council and Scientific Advisory Committee postconference meetings.
Breakthrough in cardiac arrest: reports from the 4th Paris International Conference.
Kudenchuk, Peter J; Sandroni, Claudio; Drinhaus, Hendrik R; Böttiger, Bernd W; Cariou, Alain; Sunde, Kjetil; Dworschak, Martin; Taccone, Fabio Silvio; Deye, Nicolas; Friberg, Hans; Laureys, Steven; Ledoux, Didier; Oddo, Mauro; Legriel, Stéphane; Hantson, Philippe; Diehl, Jean-Luc; Laterre, Pierre-Francois
2015-12-01
Jean-Luc Diehl The French Intensive Care Society organized on 5th and 6th June 2014 its 4th "Paris International Conference in Intensive Care", whose principle is to bring together the best international experts on a hot topic in critical care medicine. The 2014 theme was "Breakthrough in cardiac arrest", with many high-quality updates on epidemiology, public health data, pre-hospital and in-ICU cares. The present review includes short summaries of the major presentations, classified into six main chapters: Epidemiology of CA Pre-hospital management Post-resuscitation management: targeted temperature management Post-resuscitation management: optimizing organ perfusion and metabolic parameters Neurological assessment of brain damages Public healthcare. PMID:26380990
4th generation of the 1st level surface detector trigger in the Pierre Auger Observator
NASA Astrophysics Data System (ADS)
Szadkowski, Z.
The proposal of a new 4th generation of the Front-End with the advanced 1st level triggers for the Infill Array of the Pierre Auger Observatory and for the Auger North is described. Newest FPGA chips offer much higher capacity of logic registers and memories, as well as DSP blocks. The calibration channel, previously supported by an external dual-port RAM, has been fully implemented into FPGA chip, through a large internal memory. In turn DSP blocks allowed on implementation of much more sophisticated spectral trigger algorithms. A single chip simplified board design, newer architecture of FPGA reduced resouces utilization and power consumption. Higher sampling in the new Front- End in comparison with previous 40 MHz designs as well as free resources for new detection algotithms can be a good platform for CR radio detection technique at Auger enhancing a duty cycle for the detection of UHECR’s.
The 4th annual European League Against Rheumatism congress in Lisbon: a personal perspective
Wollheim, Frank A
2004-01-01
The 4th annual European League Against Rheumatism congress, held in Lisbon, 18–21 June 2003, had a record turnout of more than 8600 delegates and the abstract submissions increased to 2600. A heat wave and a somewhat substandard venue hampered some of the activities, notably the poster sessions. The scientific program was comprehensive and of a high class, and it was organized in 10–12 parallel sessions. The European League Against Rheumatism standing committees are expanding their activities and stimulating European cooperation (e.g. by creating databases and guidelines, and by starting research programs). The standing committees presented several areas where European cooperative work is in progress. Advances in drug therapy were a prominent theme and were well presented. Commercialism remains a problem for this meeting as for other similar large meetings, where satellite symposia surround the scientific program of the congress and often duplicate this. PMID:14979931
[Analysis of the 4th generation outer space bred Angelica dahurica by FTIR spectroscopy].
Zhu, Yan-ying; Wu, Peng-le; Liu, Mei-yi; Wang, Zhi-zhou; Guo, Xi-hua; Guan, Ying
2012-03-01
The major components of the 4th generation outer space bred angelica and the ground group were determined and analyzed by Fourier transform infrared spectroscopy (FTIR) and second derivative spectrum, considering the large mutation of the plants with space mutagenesis. The results show that the content of the coumarin (1741 cm(-1)), which is the main active components of the space angelica dahurica increased, and the content of the protein (1 459, 1 419 cm(-1)) and the fat (930 cm(-1)) increased slightly, whereas the content of the starch and the dietary fiber reduced drastically. There are obvious differences between the peak values of the second derivative spectra of the plants, revealing that the outer space angelica dahurica contained amine component at 1 279 cm(-1). Space mutation breeding is favor of breeding angelica with better idiosyncrasy.
European Code against Cancer 4th Edition: Medical exposures, including hormone therapy, and cancer.
Friis, Søren; Kesminiene, Ausrele; Espina, Carolina; Auvinen, Anssi; Straif, Kurt; Schüz, Joachim
2015-12-01
The 4th edition of the European Code against Cancer recommends limiting - or avoiding when possible - the use of hormone replacement therapy (HRT) because of the increased risk of cancer, nevertheless acknowledging that prescription of HRT may be indicated under certain medical conditions. Current evidence shows that HRT, generally prescribed as menopausal hormone therapy, is associated with an increased risk of cancers of the breast, endometrium, and ovary, with the risk pattern depending on factors such as the type of therapy (oestrogen-only or combined oestrogen-progestogen), duration of treatment, and initiation according to the time of menopause. Carcinogenicity has also been established for anti-neoplastic agents used in cancer therapy, immunosuppressants, oestrogen-progestogen contraceptives, and tamoxifen. Medical use of ionising radiation, an established carcinogen, can provide major health benefits; however, prudent practices need to be in place, with procedures and techniques providing the needed diagnostic information or therapeutic gain with the lowest possible radiation exposure. For pharmaceutical drugs and medical radiation exposure with convincing evidence on their carcinogenicity, health benefits have to be balanced against the risks; potential increases in long-term cancer risk should be considered in the context of the often substantial and immediate health benefits from diagnosis and/or treatment. Thus, apart from HRT, no general recommendations on reducing cancer risk were given for carcinogenic drugs and medical radiation in the 4th edition of European Code against Cancer. It is crucial that the application of these measures relies on medical expertise and thorough benefit-risk evaluation. This also pertains to cancer-preventive drugs, and self-medication with aspirin or other potential chemopreventive drugs is strongly discouraged because of the possibility of serious, potentially lethal, adverse events.
Report of the 4th World Climate Research Programme International Conference on Reanalyses
NASA Technical Reports Server (NTRS)
Bosilovich, Michael G.; Rixen, Michel; van Oevelen, Peter; Asrar, Ghassem; Compo, Gilbert; Onogi, Kazutoshi; Simmons, Adrian; Trenberth, Kevin; Behringer, Dave; Bhuiyan, Tanvir Hossain; Capps, Shannon; Chaudhuri, Ayan; Chen, Junye; Chen, Linling; Colasacco-Thumm, Nicole; Escobar, Maria Gabriela; Ferguson, Craig R.; Ishibashi, Toshiyuki; Liberato, Margarida L. R.; Meng, Jesse; Molod, Andrea; Poli, Paul; Roundy, Joshua; Willett, Kate; Wollen, Jack
2012-01-01
The 4th WCRP International Conference on Reanalyses provided an opportunity for the international community to review and discuss the observational and modelling research, as well as process studies and uncertainties associated with reanalysis of the Earth System and its components. Characterizing the uncertainty and quality of reanalyses is a task that reaches far beyond the international community of producers, and into the interdisciplinary research community, especially those using reanalysis products in their research and applications. Reanalyses have progressed greatly even in the last 5 years, and newer ideas, projects and data are coming forward. While reanalysis has typically been carried out for the individual domains of atmosphere, ocean and land, it is now moving towards coupling using Earth system models. Observations are being reprocessed and they are providing improved quality for use in reanalysis. New applications are being investigated, and the need for climate reanalyses is as strong as ever. At the heart of it all, new investigators are exploring the possibilities for reanalysis, and developing new ideas in research and applications. Given the many centres creating reanalyses products (e.g. ocean, land and cryosphere research centres as well as NWP and atmospheric centers), and the development of new ideas (e.g. families of reanalyses), the total number of reanalyses is increasing greatly, with new and innovative diagnostics and output data. The need for reanalysis data is growing steadily, and likewise, the need for open discussion and comment on the data. The 4th Conference was convened to provide a forum for constructive discussion on the objectives, strengths and weaknesses of reanalyses, indicating potential development paths for the future.
Food-based Science Curriculum Increases 4(th) Graders Multidisciplinary Science Knowledge.
Hovland, Jana A; Carraway-Stage, Virginia G; Cela, Artenida; Collins, Caitlin; Díaz, Sebastián R; Collins, Angelo; Duffrin, Melani W
2013-10-01
Health professionals and policymakers are asking educators to place more emphasis on food and nutrition education. Integrating these topics into science curricula using hand-on, food-based activities may strengthen students' understanding of science concepts. The Food, Math, and Science Teaching Enhancement Resource (FoodMASTER) Initiative is a compilation of programs aimed at using food as a tool to teach mathematics and science. Previous studies have shown that students experiencing the FoodMASTER curriculum were very excited about the activities, became increasingly interested in the subject matter of food, and were able to conduct scientific observations. The purpose of this study was to: 1) assess 4(th) graders food-related multidisciplinary science knowledge, and 2) compare gains in food-related science knowledge after implementation of an integrated, food-based curriculum. During the 2009-2010 school year, FoodMASTER researchers implemented a hands-on, food-based intermediate curriculum in eighteen 4(th) grade classrooms in Ohio (n=9) and North Carolina (n=9). Sixteen classrooms in Ohio (n=8) and North Carolina (n=8), following their standard science curricula, served as comparison classrooms. Students completed a researcher-developed science knowledge exam, consisting of 13 multiple-choice questions administered pre- and post-test. Only subjects with pre- and post-test scores were entered into the sample (Intervention n=343; Control n=237). No significant differences were observed between groups at pre-test. At post-test, the intervention group scored (9.95±2.00) significantly higher (p=.000) than the control group (8.84±2.37) on a 13-point scale. These findings suggest the FoodMASTER intermediate curriculum is more effective than a standard science curriculum in increasing students' multidisciplinary science knowledge related to food. PMID:25152539
Food-based Science Curriculum Increases 4(th) Graders Multidisciplinary Science Knowledge.
Hovland, Jana A; Carraway-Stage, Virginia G; Cela, Artenida; Collins, Caitlin; Díaz, Sebastián R; Collins, Angelo; Duffrin, Melani W
2013-10-01
Health professionals and policymakers are asking educators to place more emphasis on food and nutrition education. Integrating these topics into science curricula using hand-on, food-based activities may strengthen students' understanding of science concepts. The Food, Math, and Science Teaching Enhancement Resource (FoodMASTER) Initiative is a compilation of programs aimed at using food as a tool to teach mathematics and science. Previous studies have shown that students experiencing the FoodMASTER curriculum were very excited about the activities, became increasingly interested in the subject matter of food, and were able to conduct scientific observations. The purpose of this study was to: 1) assess 4(th) graders food-related multidisciplinary science knowledge, and 2) compare gains in food-related science knowledge after implementation of an integrated, food-based curriculum. During the 2009-2010 school year, FoodMASTER researchers implemented a hands-on, food-based intermediate curriculum in eighteen 4(th) grade classrooms in Ohio (n=9) and North Carolina (n=9). Sixteen classrooms in Ohio (n=8) and North Carolina (n=8), following their standard science curricula, served as comparison classrooms. Students completed a researcher-developed science knowledge exam, consisting of 13 multiple-choice questions administered pre- and post-test. Only subjects with pre- and post-test scores were entered into the sample (Intervention n=343; Control n=237). No significant differences were observed between groups at pre-test. At post-test, the intervention group scored (9.95±2.00) significantly higher (p=.000) than the control group (8.84±2.37) on a 13-point scale. These findings suggest the FoodMASTER intermediate curriculum is more effective than a standard science curriculum in increasing students' multidisciplinary science knowledge related to food.
European Code against Cancer 4th Edition: Medical exposures, including hormone therapy, and cancer.
Friis, Søren; Kesminiene, Ausrele; Espina, Carolina; Auvinen, Anssi; Straif, Kurt; Schüz, Joachim
2015-12-01
The 4th edition of the European Code against Cancer recommends limiting - or avoiding when possible - the use of hormone replacement therapy (HRT) because of the increased risk of cancer, nevertheless acknowledging that prescription of HRT may be indicated under certain medical conditions. Current evidence shows that HRT, generally prescribed as menopausal hormone therapy, is associated with an increased risk of cancers of the breast, endometrium, and ovary, with the risk pattern depending on factors such as the type of therapy (oestrogen-only or combined oestrogen-progestogen), duration of treatment, and initiation according to the time of menopause. Carcinogenicity has also been established for anti-neoplastic agents used in cancer therapy, immunosuppressants, oestrogen-progestogen contraceptives, and tamoxifen. Medical use of ionising radiation, an established carcinogen, can provide major health benefits; however, prudent practices need to be in place, with procedures and techniques providing the needed diagnostic information or therapeutic gain with the lowest possible radiation exposure. For pharmaceutical drugs and medical radiation exposure with convincing evidence on their carcinogenicity, health benefits have to be balanced against the risks; potential increases in long-term cancer risk should be considered in the context of the often substantial and immediate health benefits from diagnosis and/or treatment. Thus, apart from HRT, no general recommendations on reducing cancer risk were given for carcinogenic drugs and medical radiation in the 4th edition of European Code against Cancer. It is crucial that the application of these measures relies on medical expertise and thorough benefit-risk evaluation. This also pertains to cancer-preventive drugs, and self-medication with aspirin or other potential chemopreventive drugs is strongly discouraged because of the possibility of serious, potentially lethal, adverse events. PMID:26390952
Food-based Science Curriculum Increases 4th Graders Multidisciplinary Science Knowledge
Hovland, Jana A.; Carraway-Stage, Virginia G.; Cela, Artenida; Collins, Caitlin; Díaz, Sebastián R.; Collins, Angelo; Duffrin, Melani W.
2013-01-01
Health professionals and policymakers are asking educators to place more emphasis on food and nutrition education. Integrating these topics into science curricula using hand-on, food-based activities may strengthen students’ understanding of science concepts. The Food, Math, and Science Teaching Enhancement Resource (FoodMASTER) Initiative is a compilation of programs aimed at using food as a tool to teach mathematics and science. Previous studies have shown that students experiencing the FoodMASTER curriculum were very excited about the activities, became increasingly interested in the subject matter of food, and were able to conduct scientific observations. The purpose of this study was to: 1) assess 4th graders food-related multidisciplinary science knowledge, and 2) compare gains in food-related science knowledge after implementation of an integrated, food-based curriculum. During the 2009–2010 school year, FoodMASTER researchers implemented a hands-on, food-based intermediate curriculum in eighteen 4th grade classrooms in Ohio (n=9) and North Carolina (n=9). Sixteen classrooms in Ohio (n=8) and North Carolina (n=8), following their standard science curricula, served as comparison classrooms. Students completed a researcher-developed science knowledge exam, consisting of 13 multiple-choice questions administered pre- and post-test. Only subjects with pre- and post-test scores were entered into the sample (Intervention n=343; Control n=237). No significant differences were observed between groups at pre-test. At post-test, the intervention group scored (9.95±2.00) significantly higher (p=.000) than the control group (8.84±2.37) on a 13-point scale. These findings suggest the FoodMASTER intermediate curriculum is more effective than a standard science curriculum in increasing students’ multidisciplinary science knowledge related to food. PMID:25152539
NASA Astrophysics Data System (ADS)
Marsh, J.; Zagorodnii, V.; Celinski, Z.; Camley, R. E.
2012-03-01
The nonlinear generation of high harmonic signals (up to 5th harmonic) is explored in an ultra-small waveguide which contains a thin ferromagnetic film. The strength of the different harmonics is highly tunable. In particular, the power in the 2nd and 4th harmonic signals may be enhanced by over two orders of magnitude by varying the direction of a static magnetic field with respect to the long axis of the waveguide. In contrast, the 3rd and 5th harmonics are relatively insensitive to the direction of the magnetic field. The experimental results are explained by analytical and numerical calculations.
Li, Kunyu; Baird, Margaret; Yang, Jianping; Jackson, Chris; Ronchese, Franca; Young, Sarah
2016-01-01
Adoptive cell therapies (ACTs) using tumor-reactive T cells have shown clinical benefit and potential for cancer treatment. While the majority of the current ACT are focused on using CD8+ cytotoxic T lymphocytes (CTL), others have shown that the presence of tumor-reactive CD4+ T helper (Th) cells can greatly enhance the anti-tumor activity of CD8+ CTL. However, difficulties in obtaining adequate numbers of CD4+ Th cells through in vitro expansion can limit the application of CD4 Th cells in ACT. This study aims to optimize the culture conditions for mouse CD4 T cells to provide basic information for animal studies of ACT using CD4 T cells. Taking advantage of the antigen-specificity of CD4+ Th cells from OT-II transgenic mice, we examined different methodologies for generating antigen-specific CD4+ Th1 cells in vitro. We found that cells grown in complete advanced-DMEM/F12 medium supplemented with low-dose IL-2 and IL-7 induced substantial cell expansion. These Th cells were Th1-like, as they expressed multiple Th1-cytokines and exhibited antigen-specific cytotoxicity. In addition co-transfer of these CD4+ Th1-like cells with CD8+ CTL significantly enhanced tumor regression, leading to complete cure in 80% of mice bearing established B16-OVA. These observations indicate that the CD4+ Th1-like cells generated using the method we optimized are functionally active to eliminate their target cells, and can also assist CD8+ CTL to enhance tumor regression. The findings of this study provide valuable data for further research into in vitro expansion of CD4+ Th1-like cells, with potential applications to cancer treatment involving ACT. PMID:27588200
Li, Kunyu; Baird, Margaret; Yang, Jianping; Jackson, Chris; Ronchese, Franca; Young, Sarah
2016-08-01
Adoptive cell therapies (ACTs) using tumor-reactive T cells have shown clinical benefit and potential for cancer treatment. While the majority of the current ACT are focused on using CD8(+) cytotoxic T lymphocytes (CTL), others have shown that the presence of tumor-reactive CD4(+) T helper (Th) cells can greatly enhance the anti-tumor activity of CD8(+) CTL. However, difficulties in obtaining adequate numbers of CD4(+) Th cells through in vitro expansion can limit the application of CD4 Th cells in ACT. This study aims to optimize the culture conditions for mouse CD4 T cells to provide basic information for animal studies of ACT using CD4 T cells. Taking advantage of the antigen-specificity of CD4(+) Th cells from OT-II transgenic mice, we examined different methodologies for generating antigen-specific CD4(+) Th1 cells in vitro. We found that cells grown in complete advanced-DMEM/F12 medium supplemented with low-dose IL-2 and IL-7 induced substantial cell expansion. These Th cells were Th1-like, as they expressed multiple Th1-cytokines and exhibited antigen-specific cytotoxicity. In addition co-transfer of these CD4(+) Th1-like cells with CD8(+) CTL significantly enhanced tumor regression, leading to complete cure in 80% of mice bearing established B16-OVA. These observations indicate that the CD4(+) Th1-like cells generated using the method we optimized are functionally active to eliminate their target cells, and can also assist CD8(+) CTL to enhance tumor regression. The findings of this study provide valuable data for further research into in vitro expansion of CD4(+) Th1-like cells, with potential applications to cancer treatment involving ACT. PMID:27588200
NASA Astrophysics Data System (ADS)
Hejranfar, Kazem; Ezzatneshan, Eslam
2015-11-01
A high-order compact finite-difference lattice Boltzmann method (CFDLBM) is extended and applied to accurately simulate two-phase liquid-vapor flows with high density ratios. Herein, the He-Shan-Doolen-type lattice Boltzmann multiphase model is used and the spatial derivatives in the resulting equations are discretized by using the fourth-order compact finite-difference scheme and the temporal term is discretized with the fourth-order Runge-Kutta scheme to provide an accurate and efficient two-phase flow solver. A high-order spectral-type low-pass compact nonlinear filter is used to regularize the numerical solution and remove spurious waves generated by flow nonlinearities in smooth regions and at the same time to remove the numerical oscillations in the interfacial region between the two phases. Three discontinuity-detecting sensors for properly switching between a second-order and a higher-order filter are applied and assessed. It is shown that the filtering technique used can be conveniently adopted to reduce the spurious numerical effects and improve the numerical stability of the CFDLBM implemented. A sensitivity study is also conducted to evaluate the effects of grid size and the filtering procedure implemented on the accuracy and performance of the solution. The accuracy and efficiency of the proposed solution procedure based on the compact finite-difference LBM are examined by solving different two-phase systems. Five test cases considered herein for validating the results of the two-phase flows are an equilibrium state of a planar interface in a liquid-vapor system, a droplet suspended in the gaseous phase, a liquid droplet located between two parallel wettable surfaces, the coalescence of two droplets, and a phase separation in a liquid-vapor system at different conditions. Numerical results are also presented for the coexistence curve and the verification of the Laplace law. Results obtained are in good agreement with the analytical solutions and also
PREFACE: 4th International Symposium on Instrumentation Science and Technology (ISIST'2006)
NASA Astrophysics Data System (ADS)
Jiubin, Tan
2006-10-01
On behalf of the International Program Committee of ISIST'2006 and the symposium coordinators, I would like to thank all the participants for their presence at the 4th International Symposium on Instrumentation Science and Technology (ISIST'2006), a platform for scientists, researchers and experts from different parts of the world to present their achievements and to exchange their views on ways and means to further develop modern instrumentation science and technology. In the present information age, instrumentation science and technology is playing a more and more important role, not only in the acquisition and conversion of information at the very beginning of the information transformation chain, but also in the transfer, manipulation and utilization of information. It provides an analysis and test means for bioengineering, medical engineering, life science, environmental engineering and micro/nanometer technology, and integrates these disciplines to form new subdivisions of their own. The major subject of the symposium is crossover and fusion between instrumentation science and technology and other sciences and technologies. ISIST'2006 received more than 800 full papers from 12 countries and regions, from which 300 papers were finally selected by the international program committee for inclusion in the proceedings of ISIST'2006, published in 2 volumes. The major topics include instrumentation basic theory and methodology, sensors and conversion technology, signal and image processing, instruments and systems, laser and optical fiber instrumentation, advanced optical instrumentation, optoelectronics instrumentation, MEMS, nanotechnology and instrumentation, biomedical and environmental instrumentation, automatic test and control. The International Symposium on Instrumentation Science and Technology (ISIST) is sponsored by ICMI, NSFC, CSM, and CIS, and organized by ICMI, HIT and IC-CSM, and held every two years. The 1st symposium was held in LuoYang, China in
PREFACE: 4th International Conference on Safe Production and Use of Nanomaterials (Nanosafe2014)
NASA Astrophysics Data System (ADS)
Tardif, F.; Damlencourt, J.-F.; Schuster, F.; Gaultier, V.
2015-05-01
This volume contains a collection of contributions presented at the 4th International Conference on Safe Production and Use of Nanomaterials (NANOSAFE 2014) held in Grenoble, France, from 18th to 20th November 2014. The issues of fast progress in the field of Nanosafety are up to the potential benefits that nanotechnology can bring to mankind. Making more efficient - more sustainable - easier to share mineral resources, increasing the yields of new energy technologies, enabling drugs that act selectively and locally are just few examples of the wide range of nanomaterial applications that currently benefit humanity. Nevertheless, the dynamic development of nanomaterials requires the adhesion from the general public who rightly demand major progresses in Nanosafety as a prerequisite. This is our exciting responsibility and challenge! Following the successful outcome of the three past international conferences on safe production and use of nanomaterials: Nanosafe 2008, 2010 and 2012, the organizing committee has the pleasure to welcoming you again to Minatec, Grenoble with some of the most famous specialists in the field. This year, two new topics have been added dealing with the "New Application of Nanomaterials" and "Nano-responsible Development" in addition to the usual issues addressed in previous Nanosafe conferences such as Expology, Detection and Characterization, Toxicology, Environmental Interactions, Nanomaterials Release, Life Cycle Analysis, Regulation and Standardization, Risk Management. The debates in 2012 proved highly successful so this formula has been kept in 2014 with 3 round tables: Nano-Responsible Development, Risks and Benefits for the Environment, Toxicology Progress. In this 4th edition, there were more than 330 registered participants from 28 different countries including 160 oral presentation covering the whole Nanosafety issues in 12 sessions, satellite workshops and round tables. This high number of participants makes this edition one of
Göktalay, Tuğba; Cengiz Özyurt, Beyhan; Sakar Coşkun, Ayşin; Celik, Pinar
2011-01-01
The levels of smoking of 1st and 2nd year students at Faculty of Medicine and Manisa School of Health at Celal Bayar University were investigated in 2006-2007. This study is carried out in order to see if there is a change in the same students' level of smoking while they are in 3rd and 4th year. In addition, the study aimed to examine the factors affecting the level of use and attitudes towards the law effectuated in July 19, 2009. This is a follow-up study with 80.42% return rate. A 26-item structured questionnaire was administered. The participants filled out the questionnaires under supervision of the researchers in their classrooms. The University Institutional Review Board approved the study. The total of participants (263) of the follow-up study included 189 female and 74 male. The rate of experimenting with smoking was 49% with the mean age of 15.7 (SD= 4.01 years). The mean age of experimenting with smoking was the earliest on male students studying at faculty of medicine. The level of smoking was found to be the most on females, studying at faculty of medicine and staying at the dormitory, with smoking parents (p< 0.05). The most important reason to begin smoking was curiosity (55.2%) while bad breath and yellowing of teeth were the reasons to quit (91.7%). 83.3% of the students thought that the law will be effective on quit smoking. The level of both experimenting and use of smoking has been increased over time. It is suggested that medical students' awareness about the danger of smoking should be raised at earlier grades. In addition, lectures should be offered to students at School of Health and they should be encouraged to unite in order to fight with smoking.
Göktalay, Tuğba; Cengiz Özyurt, Beyhan; Sakar Coşkun, Ayşin; Celik, Pinar
2011-01-01
The levels of smoking of 1st and 2nd year students at Faculty of Medicine and Manisa School of Health at Celal Bayar University were investigated in 2006-2007. This study is carried out in order to see if there is a change in the same students' level of smoking while they are in 3rd and 4th year. In addition, the study aimed to examine the factors affecting the level of use and attitudes towards the law effectuated in July 19, 2009. This is a follow-up study with 80.42% return rate. A 26-item structured questionnaire was administered. The participants filled out the questionnaires under supervision of the researchers in their classrooms. The University Institutional Review Board approved the study. The total of participants (263) of the follow-up study included 189 female and 74 male. The rate of experimenting with smoking was 49% with the mean age of 15.7 (SD= 4.01 years). The mean age of experimenting with smoking was the earliest on male students studying at faculty of medicine. The level of smoking was found to be the most on females, studying at faculty of medicine and staying at the dormitory, with smoking parents (p< 0.05). The most important reason to begin smoking was curiosity (55.2%) while bad breath and yellowing of teeth were the reasons to quit (91.7%). 83.3% of the students thought that the law will be effective on quit smoking. The level of both experimenting and use of smoking has been increased over time. It is suggested that medical students' awareness about the danger of smoking should be raised at earlier grades. In addition, lectures should be offered to students at School of Health and they should be encouraged to unite in order to fight with smoking. PMID:22233305
A Teaching Model for Scaffolding 4th Grade Students' Scientific Explanation Writing
NASA Astrophysics Data System (ADS)
Yang, Hsiu-Ting; Wang, Kuo-Hua
2014-08-01
Improving students scientific explanations is one major goal of science education. Both writing activities and concept mapping are reported as effective strategies for enhancing student learning of science. The purpose of this study was to examine the effect of a teaching model, named the DCI model, which integrates a Descriptive explanation writing activity, Concept mapping, and an Interpretive explanation writing activity, is introduced in a 4th grade science class to see if it would improve students' scientific explanations and understanding. A quasi-experimental design, including a non-randomized comparison group and a pre- and post-test design, was adopted for this study. An experimental group of 25 students were taught using the DCI teaching model, while a comparison group received a traditional lecture teaching. A rubric and content analysis was used to assess students' scientific explanations. The independent sample t test was used to measure difference in conceptual understanding between the two groups, before and after instruction. Then, the paired t test analysis was used to understand the promotion of the DCI teaching model. The results showed that students in the experimental group performed better than students in the comparison group, both in scientific concept understanding and explanation. Suggestions for using concept mapping and writing activities (the DCI teaching model) in science classes are provided in this study.
4th-International Symposium on Ultrafast Surface Science - Final Report
Hrvoje Petek
2005-01-26
The 4-th International Symposium on Ultrafast Surface Dynamics (UDS4) was held at the Telluride Summer Research Center on June 22-27, 2003. The International Organizing Committee consisting of Hrvoje Petek (USA), Xiaoyang Zhu (USA), Pedro Echenique (Spain) and Maki Kawai (Japan) brought together a total of 51 participants 16 of whom were from Europe, 10 from Japan, and 25 from the USA. The focus of the conference was on ultrafast electron or light induced processes at well-defined surfaces. Ultrafast surface dynamics concerns the transfer of charge and energy at solid surfaces on the femtosecond time scale. These processes govern rates of fundamental steps in surface reactions, interfacial electron transfer in molecular electronics, and relaxation in spin transport. Recent developments in femtosecond laser technology make it possible to measure by a variety of nonlinear optical techniques directly in the time domain the microscopic rates underlying these interfacial processes. Parallel progress in scanning probe microscopy makes it possible at a single molecular level to perform the vibrational and electronic spectroscopy measurements, to induce reactions with tunneling electrons, and to observe their outcome. There is no doubt that successful development in the field of ultrafast surface dynamics will contribute to many important disciplines.
The 4th Annual Meeting of the American Society for Nanomedicine.
Gendelman, Howard E; Balogh, Lajos P; Bawa, Raj; Bradbury, Michelle; Chang, Esther H; Chiu, Wah; Farokhzad, Omid; Foldvari, Marianna; Lanza, Gregory; Wang, Kuan
2014-03-01
The 4th Conference of the American Society for Nanomedicine is being held March 28-30, 2014 at the Universities at Shady Grove, Rockville, Maryland. The meeting's theme is on defining the role of nanomedicines for nervous system diagnostics and disease but balanced by broad and timely topics for nanotechnology. Nanoneuromedicine, as defined by the development of small drug formulations for the diagnosis and treatment of degenerative, inflammatory, infectious, vascular, addictive, behavioral and metabolic disorders of the nervous system, will provide a focus for each of the scientific sessions. This research is interdisciplinary and it's in its infancy. The hurdles that preclude translation from bench to bedside would include its delivery across the blood brain barrier, limiting nervous system toxicities, and improving drug targeting to diseased brain subregions. These all pose challenges. Multidisciplinary works in neuroscience (neurobiology, neurochemistry, neurophysiology, and neuroinflammation), bioimaging, and polymer chemistry to facilitate outcomes for formulation manufacture will be vigorously discussed. How drugs reach sites of action need include neural cell specific subcellular compartments. The ASNM meeting will showcase nanoneuromedicine research from leading investigators of divergent scientific backgrounds who define this new field. It will also serve as an incubator for developing investigators and broad new field discoveries. Welcome to the conference and enjoy!
Need for Specific Sugar-Sweetened Beverage Lessons for 4th and 5th Graders
Bea, Jennifer W.; Jacobs, Laurel; Waits, Juanita; Hartz, Vern; Martinez, Stephanie H.; Standfast, Rebecca D.; Farrell, Vanessa A.; Bawden, Margine; Whitmer, Evelyn; Misner, Scottie
2015-01-01
Objective Consumption of sugar-sweetened beverages (SSB) is linked to obesity. We hypothesized that school-based nutrition education would decrease SSB consumption. Design Self-selected interventional cohort with random selection for pre and post measurements Setting Arizona SNAP-Ed eligible schools Participants Randomly selected (9%) 4th and 5th grade classroom students Intervention The University of Arizona Nutrition Network (UANN) provided general nutrition education training and materials to teachers, to be delivered to their students. The UANN administered behavioral questionnaires to students in both Fall and Spring. Main Outcome Measure(s) Change in SSB consumption Analyses Descriptive statistics were computed for student demographics and beverage consumption on the day prior to testing. Paired t-tests evaluated change in classroom averages. Linear regression assessed potential correlates of SSB consumption. Results Fall mean SSB consumption was 1.1 (±0.2) times; mean milk and water intake were 1.6 (±0.2) and 5.2 (±0.7) times, respectively. Beverage consumption increased (3.2%) in springtime, with increased SSBs (14.4%) accounting for the majority (p=0.006). Change in SSB consumption was negatively associated with baseline SSB and water consumption, but positively associated with baseline milk fat (p≤0.05). Conclusions and Implications The results suggest the need for beverage specific education to encourage children to consume more healthful beverages in warmer weather. PMID:25239840
Project ASTRO: Local Coalitions for Bringing Astronomers to 4th - 9th Grade Classrooms
NASA Astrophysics Data System (ADS)
Fraknoi, Andrew
1998-05-01
We report on Project ASTRO, an NSF and NASA funded program that now links professional and amateur astronomers with local 4th through 9th grade teachers in 10 sites around the country. Each site matches and trains about 20-25 astronomer-teacher partnerships per year, focusing on hands-on, age-appropriate activities, demonstrations of the scientific method, as well as family and community outreach. Over 10,000 copies of the project's 813-page UNIVERSE AT YOUR FINGERTIPS resource and activity notebook (published by the A.S.P) are now in use in educational institututions around the world. The project's HOW-TO-MANUAL is being used as a practical guide to establishing astronomer-teacher partnerships where no formal ASTRO site exists, and a 12-minute video explaining and demonstrating the project is also available. In each of the ten sites, a coalition of educational and scientific institutions is assisting the project with in-kind donations, publicity, personnel, training, materials, etc. We are conducting an experiment (at the behest of NSF) to see to what degree the sites can become self-supporting over time. (One site, in Salt Lake City, has already received full funding from a local foundation.) We will discuss the progress of the project and will have a variety of sample materials available, including our annotated catalog of national astronomy and space science education projects (see associated URL).
Multiwavelength Analysis of a Moving Type-IV Radio Burst on 4th March 2012
NASA Astrophysics Data System (ADS)
Veluchamy, V.; Chen, Y.; Feng, S.; Du, G.; Song, H.; Kong, X.
2015-12-01
We performed a multiwavelength analysis of a moving Type-IV radio burst on 4th march 2012. The Type-IV radio burst is observed between 10:39 - 11:00 UT in the frequency range of 300 - 20 MHz. From the radio heliographic observation, the radio source of the type-IV burst is traced and their sky plane speed is estimated as ~ 370 km/s. A plasmoid structure is ejected during the impulsive phase of the flare, at the same time of the type-IV burst and the structure is clearly observed at SDO/AIA 131 Å channel. From this, we find that the radio source moves with the plasmoid. The high brightness temperature profile in the range of 108 - 109 K and the moderate polarization between -50 - 30 % supports the plasma emission mechanism. Further the differential emission measure (DEM) analysis will be carried out and their results will be presented to provide more evidence of the emission mechanism.
4th annual primary care ethics conference: ethics education and lifelong learning
Spicer, John; McKenzie-Edwards, Emma; Misselbrook, David
2014-01-01
Primary care ethics is a field of study that has recently found new life, with calls to establish the relevance of ethical discussion in general practice, to gather a body of literature and to carve out an intellectual space for primary care on the academic landscape of bioethics. In this report, we reflect on the key strands of the 4th primary care ethics conference held at the Royal Society of Medicine, on a theme of ethics education and lifelong learning: first, to produce insights that have relevance for policy and practice; and second, to illustrate the idea that not only is ethics relevant in primary care, but primary care is relevant in medical ethics. Core themes included the advantages and disadvantages of prescriptive ways of doing ethics in education, ethical reflection and potential risk to professional status, the need to deal with societal change and to take on board the insights gained from empirical work, whether this is about different kinds of fatherhood, or work on the causes of moral distress in healthcare workers. PMID:25949739
European Code against Cancer 4th Edition: 12 ways to reduce your cancer risk.
Schüz, Joachim; Espina, Carolina; Villain, Patricia; Herrero, Rolando; Leon, Maria E; Minozzi, Silvia; Romieu, Isabelle; Segnan, Nereo; Wardle, Jane; Wiseman, Martin; Belardelli, Filippo; Bettcher, Douglas; Cavalli, Franco; Galea, Gauden; Lenoir, Gilbert; Martin-Moreno, Jose M; Nicula, Florian Alexandru; Olsen, Jørgen H; Patnick, Julietta; Primic-Zakelj, Maja; Puska, Pekka; van Leeuwen, Flora E; Wiestler, Otmar; Zatonski, Witold
2015-12-01
This overview describes the principles of the 4th edition of the European Code against Cancer and provides an introduction to the 12 recommendations to reduce cancer risk. Among the 504.6 million inhabitants of the member states of the European Union (EU28), there are annually 2.64 million new cancer cases and 1.28 million deaths from cancer. It is estimated that this cancer burden could be reduced by up to one half if scientific knowledge on causes of cancer could be translated into successful prevention. The Code is a preventive tool aimed to reduce the cancer burden by informing people how to avoid or reduce carcinogenic exposures, adopt behaviours to reduce the cancer risk, or to participate in organised intervention programmes. The Code should also form a base to guide national health policies in cancer prevention. The 12 recommendations are: not smoking or using other tobacco products; avoiding second-hand smoke; being a healthy body weight; encouraging physical activity; having a healthy diet; limiting alcohol consumption, with not drinking alcohol being better for cancer prevention; avoiding too much exposure to ultraviolet radiation; avoiding cancer-causing agents at the workplace; reducing exposure to high levels of radon; encouraging breastfeeding; limiting the use of hormone replacement therapy; participating in organised vaccination programmes against hepatitis B for newborns and human papillomavirus for girls; and participating in organised screening programmes for bowel cancer, breast cancer, and cervical cancer. PMID:26164654
European Code against Cancer 4th Edition: Ultraviolet radiation and cancer.
Greinert, Rüdiger; de Vries, Esther; Erdmann, Friederike; Espina, Carolina; Auvinen, Anssi; Kesminiene, Ausrele; Schüz, Joachim
2015-12-01
Ultraviolet radiation (UVR) is part of the electromagnetic spectrum emitted naturally from the sun or from artificial sources such as tanning devices. Acute skin reactions induced by UVR exposure are erythema (skin reddening), or sunburn, and the acquisition of a suntan triggered by UVR-induced DNA damage. UVR exposure is the main cause of skin cancer, including cutaneous malignant melanoma, basal-cell carcinoma, and squamous-cell carcinoma. Skin cancer is the most common cancer in fair-skinned populations, and its incidence has increased steeply over recent decades. According to estimates for 2012, about 100,000 new cases of cutaneous melanoma and about 22,000 deaths from it occurred in Europe. The main mechanisms by which UVR causes cancer are well understood. Exposure during childhood appears to be particularly harmful. Exposure to UVR is a risk factor modifiable by individuals' behaviour. Excessive exposure from natural sources can be avoided by seeking shade when the sun is strongest, by wearing appropriate clothing, and by appropriately applying sunscreens if direct sunlight is unavoidable. Exposure from artificial sources can be completely avoided by not using sunbeds. Beneficial effects of sun or UVR exposure, such as for vitamin D production, can be fully achieved while still avoiding too much sun exposure and the use of sunbeds. Taking all the scientific evidence together, the recommendation of the 4th edition of the European Code Against Cancer for ultraviolet radiation is: "Avoid too much sun, especially for children. Use sun protection. Do not use sunbeds." PMID:26096748
Effectiveness of fenbendazole against later 4th-stage Strongylus vulgaris in ponies.
Slocombe, J O; McCraw, B M; Pennock, P W; Baird, J D
1983-12-01
Twelve pony foals (reared worm-free) were inoculated with Strongylus vulgaris. Approximately 8 weeks later, 4 of the foals were given fenbendazole (10% suspension) at a dosage rate of 10 mg/kg of body weight daily for 5 days and 4 foals were given the suspension at a dosage rate of 50 mg/kg daily for 3 days; the remaining foals were given a placebo. All treatments were administered by stomach tube. Fenbendazole was 99.6 and 97.9% effective in the 2 treatment groups, respectively, in eliminating later 4th-stage S vulgaris larvae located near the origin of major intestinal arteries. On microscopic examination of the ileocolic artery from fenbendazole-treated foals, a few larval remnants were found beneath the tunica intima in small organized mural thrombi overgrown with endothelium. It would appear that larvae are rapidly destroyed after administration of fenbendazole. A pony foal reared on pasture and with arteriographic evidence of arteritis of the cranial mesenteric and ileocolic arteries was treated with fenbendazole (10% suspension) by stomach tube at a dosage rate of 50 mg/kg of body weight daily for 3 days. By arteriographic examination made 4 weeks later, there was evidence of regression of the lesion, and at necropsy done a week later, there was no arteritis or larvae in the lumen of those arteries.
European Code against Cancer 4th Edition: Ultraviolet radiation and cancer.
Greinert, Rüdiger; de Vries, Esther; Erdmann, Friederike; Espina, Carolina; Auvinen, Anssi; Kesminiene, Ausrele; Schüz, Joachim
2015-12-01
Ultraviolet radiation (UVR) is part of the electromagnetic spectrum emitted naturally from the sun or from artificial sources such as tanning devices. Acute skin reactions induced by UVR exposure are erythema (skin reddening), or sunburn, and the acquisition of a suntan triggered by UVR-induced DNA damage. UVR exposure is the main cause of skin cancer, including cutaneous malignant melanoma, basal-cell carcinoma, and squamous-cell carcinoma. Skin cancer is the most common cancer in fair-skinned populations, and its incidence has increased steeply over recent decades. According to estimates for 2012, about 100,000 new cases of cutaneous melanoma and about 22,000 deaths from it occurred in Europe. The main mechanisms by which UVR causes cancer are well understood. Exposure during childhood appears to be particularly harmful. Exposure to UVR is a risk factor modifiable by individuals' behaviour. Excessive exposure from natural sources can be avoided by seeking shade when the sun is strongest, by wearing appropriate clothing, and by appropriately applying sunscreens if direct sunlight is unavoidable. Exposure from artificial sources can be completely avoided by not using sunbeds. Beneficial effects of sun or UVR exposure, such as for vitamin D production, can be fully achieved while still avoiding too much sun exposure and the use of sunbeds. Taking all the scientific evidence together, the recommendation of the 4th edition of the European Code Against Cancer for ultraviolet radiation is: "Avoid too much sun, especially for children. Use sun protection. Do not use sunbeds."
PREFACE: 4th National Conference on Processing and Characterization of Materials (NCPCM 2014)
NASA Astrophysics Data System (ADS)
2015-02-01
This volume contains selected full length technical papers amongst forty oral presentations made in the 4th National Conference on Processing and Characterization of Materials (NCPCM 2014), NIT Rourkela, Rourkela, Odisha, India, December 5 - 6, 2014. The first conference of the NCPCM series was held at the same place in December 2011. Seeing the enthusiasm of the participants, it was decided to organize such conference in Rourkela every year. The basic idea was to establish a periodical national forum for multi-scale approaches in processing and characterization of materials in the eastern part of India. The conference NCPCM 2014 has successfully carried the tradition of previous conferences; more than fifty participants from twenty different organizations across India have registered. The conference was consisted of six technical sessions of about fifty contributory talks along with three keynote lectures. A metallography contest was also organized during the event. Out of these, thirty four best peer-reviewed contributions are published in this volume of IOP Conference Series: Materials Science and Engineering. We would like to thank all the contributors, members of the organizing committee, session chairs as well as colleagues and students who helped with the preparation of the conference and, particularly, with the preparation of this volume. We convey our heartiest gratitude to the sponsors and advertisers for their contribution.
The relationship between the carrying angle and the distal extent of the 2nd and 4th fingertips.
Sönmez, M; Tattemur, Y; Karacan, K; Erdal, M
2012-08-01
The angle towards the lateral side between the arm and forearm when the forearm is in full extension and supination is defined as the carrying angle. It is well known that the 2nd finger is longer in women whereas the 4th finger is longer in men, due to in-utero hormonal effects. In the present study, the relationship between the carrying angle and the distal extent of the 2nd and 4th fingertips is studied. The findings reveal that the carrying angle was greater both in left and right sides in women than in men. In addition, while the distal extent of the 2nd fingertips was longer in women, the 4th fingertip was longer in men. There was a moderately positive correlation between the carrying angle and the distal fingertip lengths. Therefore, it could be suggested that the morphometric factors play role on the distal extent of the fingertips other than the hormonal effects.
Learning Natural Selection in 4th Grade with Multi-Agent-Based Computational Models
NASA Astrophysics Data System (ADS)
Dickes, Amanda Catherine; Sengupta, Pratim
2013-06-01
In this paper, we investigate how elementary school students develop multi-level explanations of population dynamics in a simple predator-prey ecosystem, through scaffolded interactions with a multi-agent-based computational model (MABM). The term "agent" in an MABM indicates individual computational objects or actors (e.g., cars), and these agents obey simple rules assigned or manipulated by the user (e.g., speeding up, slowing down, etc.). It is the interactions between these agents, based on the rules assigned by the user, that give rise to emergent, aggregate-level behavior (e.g., formation and movement of the traffic jam). Natural selection is such an emergent phenomenon, which has been shown to be challenging for novices (K16 students) to understand. Whereas prior research on learning evolutionary phenomena with MABMs has typically focused on high school students and beyond, we investigate how elementary students (4th graders) develop multi-level explanations of some introductory aspects of natural selection—species differentiation and population change—through scaffolded interactions with an MABM that simulates predator-prey dynamics in a simple birds-butterflies ecosystem. We conducted a semi-clinical interview based study with ten participants, in which we focused on the following: a) identifying the nature of learners' initial interpretations of salient events or elements of the represented phenomena, b) identifying the roles these interpretations play in the development of their multi-level explanations, and c) how attending to different levels of the relevant phenomena can make explicit different mechanisms to the learners. In addition, our analysis also shows that although there were differences between high- and low-performing students (in terms of being able to explain population-level behaviors) in the pre-test, these differences disappeared in the post-test.
NASA Astrophysics Data System (ADS)
Fricker, A.; Green, P.
2010-04-01
These conference proceedings contain the written papers of the contributions presented at the 4th International Conference on: Preservation and Conservation Issues in Digital Printing and Digital Photography. The conference was held at the Institute of Physics, London, UK on 27th-28th May 2010. Previous conferences in this series took place in 2000, 2003 and 2006. The aim of this conference series is to inform those responsible for the preservation of digitally printed materials about developments in digital photography and printing technologies. We aim to examine progress in research on inks and substrates and their significance for conservation and preservation issues and techniques. We also hope to develop links between related industries and the conservation/preservation world. Research areas explored in this conference include current developments and future trends in digital printing and photographic technologies; the effect of environmental, storage and salvage conditions on the durability of digital prints and photographs; image processing techniques; image permanence considerations and standards for fastness, permanence and the role of scanning and file formats. We would like to thank all participants for their contribution to the conference programme and these proceedings. Our thanks go to Ms C. Gu and Mr M. Sandy for chairing conference sessions. We are also grateful to Dawn Stewart and the Institute of Physics Conference Team for their invaluable support and assistance in arranging the conference and reception. Finally we would like to extend our thanks to the Society of Imaging Science and Technology (IS&T) for their sponsorship support. The Editors Acknowledgements Conference Organising Committee: Ms A Fricker and Dr. P Green (London College of Communication, University of the Arts London). Proceedings edited and compiled by Ms A Fricker and Dr. P Green.
NASA Astrophysics Data System (ADS)
Wang, Alexandre; Abe, Sumiyoshi; Li, Wei
2015-04-01
This volume contains 24 contributed papers presented at the 4th International Workshop on Statistical Physics and Mathematics for Complex Systems (SPMCS) held during October 12-16, 2014 in Yichang, China. Each paper was peer-reviewed by at least one referee chosen from a distinguished international panel. The previous three workshops of this series were organized in 2008, 2010, and 2012, in Le Mans, France, Wuhan, China, and Kazan, Russia, respectively. The SPMCS international workshop series is destined mainly to communicate and exchange research results and information on the fundamental challenges and questions in the vanguard of statistical physics, thermodynamics and mathematics for complex systems. More specifically, the topics of interest touch, but are not limited to, the following: • Fundamental aspects in the application of statistical physics and thermodynamics to complex systems and their modeling • Finite size and non-extensive system • Fluctuation theorems and equalities, quantum thermodynamics • Variational principle for random dynamics • Fractal geometry, fractional mathematics More than 50 participants from 7 countries participated in SPMCS-2014. 35 oral contributions were presented at the workshop. We would like to take this opportunity to thank the members of the Scientific Program Committee, many of whom acted as reviewers of the papers and responded promptly. We would also like to thank the organizing committee, the session chairs, the technicians and the students for the smooth running of the whole workshop. Thanks also go to China Three Gorges University who provided generous support for the conference venue, as well as exquisite refreshments for the tea breaks. The workshop was also partially supported by Central China Normal University and the Programme of Introducing Talents of Discipline to Universities under grant NO. B08033. Special thanks are due to Ms Juy Zhu who has done excellent editing work with great effort.
The Ratio of 2nd to 4th Digit Length in Korean Alcohol-dependent Patients
Han, Changwoo; Bae, Hwallip; Lee, Yu-Sang; Won, Sung-Doo; Kim, Dai Jin
2016-01-01
Objective The ratio of 2nd to 4th digit length (2D:4D) is a sexually dimorphic trait. Men have a relatively shorter second digit than fourth digit. This ratio is thought to be influenced by higher prenatal testosterone level or greater sensitivity to androgen. The purpose of this study is to investigate the relationship between alcohol dependence and 2D:4D in a Korean sample and whether 2D:4D can be a biologic marker in alcohol dependence. Methods In this study, we recruited 87 male patients with alcohol dependence from the alcohol center of one psychiatric hospital and 52 healthy male volunteers who were all employees in the same hospital as controls. We captured images of the right and left hands of patients and controls using a scanner and extracted data with a graphics program. We measured the 2D:4D of each hand and compared the alcohol dependence group with the control group. We analyzed these ratios using an independent-samples t-test. Results The mean 2D:4D of patients was 0.934 (right hand) and 0.942 (left hand), while the mean 2D:4D of controls was 0.956 (right hand) and 0.958 (left hand). Values for both hands were significantly lower for patients than controls (p<0.001, right hand; p=0.004, left hand). Conclusion Patients who are alcohol dependent have a significantly lower 2D:4D than controls, similar to the results of previous studies, which suggest that a higher prenatal testosterone level in the gonadal period is related to alcoholism. Furthermore, 2D:4D is a possible predictive marker of alcohol dependence. PMID:27121425
PREFACE: CYGNUS 2013: 4th Workshop on Directional Detection of Dark Matter
NASA Astrophysics Data System (ADS)
Naka, Tatsuhiro; Miuchi, Kentaro
2013-12-01
It is a great pleasure to publish the proceedings of the 4th Workshop on Directional Detection of Dark Matter held in Toyama, Japan on 10-12 June 2013 (CYGNUS 2013). These proceedings contain written versions of the presentations made at CYGNUS 2013 as scientific outputs of the directional detection of dark matter. The GYGNUS workshop started in 2007 at Boulby Underground Laboratory (UK), followed by CYGNUS 2009 (MIT in Cambridge, Massachusetts, USA) and CYGNUS 2011 (AUSSOIS, France). CYGNUS 2013 was held by the combination of a two and a half days of scientific program and a half day visit to the underground laboratory (Kamioka Observatory) as a 'tradition' of CYGNUS workshops. The name 'CYGNUS' came from the fact that the 'dark matter wind' is expected to come from the direction of the constellation Cygnus due to the motion of the Solar system in the galaxy. A general aim of these CYGNUS workshops is to bring together the theoretical and experimental studies on the directional dark matter detection. Directional detection of dark matter is a promising approach to a 'clear detection' and also to 'further investigations' of galactic dark matter, or Weakly Interacting Massive Particles (WIMPs). Directional detection requires the simultaneous detection of the energy and track of low energy recoils. Among many technological challenges for the requirement above, three of them, namely size, background, and directionality (angular resolution and head-tail detection), are most important to demonstrate and improve the quality as a dark matter detector. In the workshop, up-to-date activities by the international reserchers are discussed. The workshop was a great success thanks to the oral contributions and fruitful discussions held throughout the workshop period. We hope that readers will remember and share the great enthusiasm shown during the CYGNUS 2013 workshop. The Editors Tatsuhiro Naka and Kentaro Miuchi
4th International Conference on Energy and Environment 2013 (ICEE 2013)
NASA Astrophysics Data System (ADS)
Chakrabarty, Chandan Kumar; Shamsuddin, Abd Halim Bin; Ahmad, Ibrahim Bin; Desa, Mohamed Nor Bin Mohamed; Din, Norashidah Bte Md; Bte Mohd, Lariyah; Hamid, Nasri A.; See, Ong Hang; Hafiz Nagi, Farrukh; Yong, Lee Choon; Pasupuleti, Jagadeesh; Mei, Goh Su; Abdullah, Fairuz Bin; Satgunam, Meenaloshini
2013-06-01
The 4th International Conference on Energy & Environment 2013 (ICEE2013) was organized by the Universiti Tenaga Nasional (UNITEN) to provide a platform for creating and sharing ideas among engineers, researchers, scientists, industrialists and students in sustainable green energy and technologies. The theme 'Shaping a Sustainable Future through Advancement in Green Energy Technology' is in line with the University's vision to be a leading global energy university that shapes a sustainable future. The general scopes of the conference are renewable energy, smart grid, green technology, energy policies and economics, sustainable green energy and environment, sustainable education, international cooperation and innovation and technology transfer. Five international keynote speakers delivered their speeches in specialized areas of green energy technology and sustainability. In addition, the conference highlights several special parallel sessions by notable invited presenters in their niche areas, which are: Hybrid Energy Power Quality & Distributed Energy Smart Grid Nuclear Power & Technologies Geohazard Management Greener Environment for Sustainability Advances in Computational Fluid Dynamics The research papers presented in ICEE2013 are included in this volume of IOP Conference Series: Earth and Environmental Science (EES). EES is abstracted and indexed in SCOPUS, GeoBase, GeoRef, Compendex, Inspec, Chemical Abstracts Service, NASA Astrophysics Data System, and International Nuclear Information System (INIS). With the comprehensive programme outline, the organizing committee hopes that the ICEE2013 was a notable intellectual sharing session for the research and academic community in Malaysia and regionally. The organizing committee expresses gratitude to the ICEE2013 delegates for their great support and contributions to the event.
ERIC Educational Resources Information Center
LaRusso, Maria; Jones, Stephanie M.; Kim, Ha Yeon; Kim, James; Donovan, Suzanne; Snow, Catherine
2016-01-01
This paper presents an exploratory analysis of treatment-control differences in the quality of classroom interactions in 4th through 7th grade urban classrooms. Word Generation (WG) is a research-based academic language program for middle school students designed to teach novel vocabulary and literacy through language arts, math, science, and…
ERIC Educational Resources Information Center
Gelmez Burakgazi, Sevinc; Yildirim, Ali; Weeth Feinstein, Noah
2016-01-01
Rooted in science education and science communication studies, this study examines 4th and 5th grade students' perceptions of science information sources (SIS) and their use in communicating science to students. It combines situated learning theory with uses and gratifications theory in a qualitative phenomenological analysis. Data were gathered…
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-17
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Stockton Ports Baseball Club/City of... Ports Baseball Club and the City of Stockton will sponsor the Stockton Ports Baseball Club/City of... Ports Baseball Club/City of Stockton 4th of July Fireworks Display, Stockton, CA. (a) Location....
Impact of a Health and Media Literacy Curriculum on 4th-Grade Girls: A Qualitative Study
ERIC Educational Resources Information Center
Fuller, Heidi A.; Damico, Amy M.; Rodgers, Shannon
2004-01-01
Recent research indicates that young girls are preoccupied with their body size and that the media may be a contributing factor. This study aimed to discover the impact of an interdisciplinary media literacy intervention curriculum on 4th-grade girls in an urban elementary school. The authors developed and implemented a series of lessons that…
ERIC Educational Resources Information Center
Pechenizkiy, Mykola; Calders, Toon; Conati, Cristina; Ventura, Sebastian; Romero, Cristobal; Stamper, John
2011-01-01
The 4th International Conference on Educational Data Mining (EDM 2011) brings together researchers from computer science, education, psychology, psychometrics, and statistics to analyze large datasets to answer educational research questions. The conference, held in Eindhoven, The Netherlands, July 6-9, 2011, follows the three previous editions…
ERIC Educational Resources Information Center
Smith, John; Nichols, David; Biggerstaff, Kyle; DiMarco, Nancy
2009-01-01
The purpose of this study was to determine the amount of physical activity in which children engage during physical education classes and factors that mediate their participation. Third and 4th grade students wore pedometers during each 30-min physical education class for one school year. Steps per class were collected daily during structured and…
ERIC Educational Resources Information Center
Foorman, Barbara R.; Koon, Sharon; Petscher, Yaacov; Mitchell, Alison; Truckenmiller, Adrea
2015-01-01
The objective of this study was to explore dimensions of oral language and reading and their influence on reading comprehension in a relatively understudied population--adolescent readers in 4th through 10th grades. The current study employed latent variable modeling of decoding fluency, vocabulary, syntax, and reading comprehension so as to…
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-06
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75 FR 34379 - Safety Zone; Mackinac Island 4th of July Fireworks, Lake Huron, Mackinac Island, MI
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-17
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Mackinac Island 4th of July Fireworks, Lake Huron, Mackinac Island, MI AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on Lake Huron, Mackinac Island, Michigan. This zone...
Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-03
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Eighth Coast Guard District Annual Safety Zones; Niceville July 4th Fireworks Show; Boggy Bayou; Niceville, FL AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement of regulation. SUMMARY: The Coast Guard will enforce a Safety Zone for the Niceville July...
ERIC Educational Resources Information Center
Yager, Robert E.; Choi, AeRan; Yager, Stuart O.; Akcay, Hakan
2009-01-01
Fifteen 4th-, 5th-, and 6th-grade teachers from five school districts each taught two sections of science--one with a Science-Technology-Society (STS) approach and the other with a more traditional textbook approach in which basic science concepts were the major organizers. Local, current, and personally relevant issues provided the context and…
Using Inquiry-Based Instruction to Teach Research Methods to 4th-Grade Students in an Urban Setting
ERIC Educational Resources Information Center
Hamm, Ellen M.; Cullen, Rebecca; Ciaravino, Melissa
2013-01-01
When a college professor who teaches research methods to graduate education students was approached by a local public urban elementary school to help them teach research skills to 4th-graders, it was thought that the process would be simple--take what we did at the college level and differentiate it for the childhood classroom. This article will…
Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-03
... enhance safety and improve the visual effect of the fireworks for the 2012 Macy's 4th of July Fireworks... Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking COTP...'' in the Federal Register (76 FR 69613). In that rulemaking, the Coast Guard established a...
ERIC Educational Resources Information Center
Mthembu, T.
2012-01-01
The South African Technology Network (SATN) would like to thank the Editor of the "South African Journal of Higher Education" (SAJHE) for the opportunity to publish papers read at the 4th Annual SATN Conference that was hosted by Central University of Technology and held in Bloemfontein in November 2011. The journal makes it possible for…
The Influence of Neighborhood Density and Word Frequency on Phoneme Awareness in 2nd and 4th Grades
ERIC Educational Resources Information Center
Hogan, Tiffany P.; Bowles, Ryan P.; Catts, Hugh W.; Storkel, Holly L.
2011-01-01
Purpose: The purpose of this study was to test the hypothesis that two lexical characteristics--neighborhood density and word frequency--interact to influence performance on phoneme awareness tasks. Methods: Phoneme awareness was examined in a large, longitudinal dataset of 2nd and 4th grade children. Using linear logistic test model, the relation…
NASA Astrophysics Data System (ADS)
Lay Ekuakille, Aimé; Mukhopadhyay, Subhas C.
2011-12-01
Sensor systems are one the most requested topics in the field of engineering. The importance of sensors, their technologies and their applications is self-evident through their impact on daily life. The features of sensors can still be improved and this is a matter of increasing research in the international scientific community. Several papers have been selected and reviewed to constitute a recipe for understanding advances in the area of sensors. Although they are few in number, the papers accepted for publication in this special feature of Measurement Science and Technology reflect current trends in the related areas, that is to say, resistive chemical sensing, new transducers, and applications in robotics, in olfaction and in image processing. In addition to these topics, the concept of the functionalization of nanotubes is also of great interest, as is the subject of nanowires. We thank the authors of this special feature for their contributions with dedicated papers in the areas of sensors and sensor systems. We also thank MST for hosting this special feature in order to give further expression to authors from ICST2010, the International Conference on Sensing Technology that took place in Lecce (Italy) in 2010.
PREFACE: 4th Global Conference on Materials Science and Engineering (CMSE 2015)
NASA Astrophysics Data System (ADS)
Ruda, H. E.; Khotsianovsky, A.
2015-12-01
IOP Conference Series: Materials Science and Engineering is publishing a volume of conference proceedings that contains a selection of papers presented at the 4th Global Conference on Materials Science and Engineering (CMSE 2015), which is an annual event that started in 2012. CMSE 2015, technically supported by the Institute of Applied Physics and Materials Engineering of University of Macau, organized by Wuhan Advance Materials Society, was successfully held at the University of Macau-new campus located on Hengqin Island from August 3rd-6th, 2015. It aims to bring together leading academic scientists, researchers and scholars to exchange and share their experience and research results on all aspects of Materials Science and Engineering, and to discuss the practical challenges encountered and the solutions adopted. Macau, one of the two special administrative regions of the People's Republic of China, where East meets West, turned out to be an ideal meeting place for domestic and overseas participants of this annual international conference. The conference program included keynote presentations, special sessions, oral and poster contributions. From several hundred submissions, 52 of the most promising and mainstream, IOP-relevant, contributions were included in this volume. The submissions present original ideas or results of general significance, supported by clear reasoning, compelling evidence and methods, theories and practices relevant to the research. The authors state clearly the problems and the significance of their research to theory and practice. Being a successful conference, this event gathered more than 200 qualified and high-level researchers and experts from over 40 countries, including 10 keynote speakers from 6 countries, which created a good platform for worldwide researchers and engineers to enjoy the academic communication. Taking advantage of this opportunity, we would like to thank all participants of this conference, and particularly the
4th Rare Disease South Eastern Europe (See) Meeting Skopje, Macedonia (November 14th, 2015).
Gucev, Zoran; Tasic, Velibor; Polenakovic, Momir
2015-01-01
The 4th meeting on rare diseases in South Eastern Europe (SEE) was held in Skopje, at the Macedonian Academy of Sciences and Arts (MASA) on the 14(th) of November 2015. The focuses were metabolic, rare brain diseases as well as the rare dysmorphic syndrome. The authors of the report are particularly keen on stating that one of the main goals of the meeting, namely to help the treatment of patients with rare disease has begun to bear fruits. The talk on an iminosugar-based pharmacological chaperone compound as a drug candidate for the treatment of GM1-gangliosidosis and mucopolysaccharidosis IVB (Morquio disease type B) was enlightening. To date, there is no treatment available to be offered to patients, but chaperones lead mutated proteins to adopt a native-like conformation and to successfully traffic to their normal cellular destination. DORPHAN is developing an iminosugar-based pharmacological chaperone compound for the treatment of GM1-gangliosidosis and mucopolysaccharidosis IVB. A talk on recent developments in the laboratory diagnosis of mucopolysaccharidoses (MPS) was particularly interesting, covering the laboratory diagnosis of the MPS diseases by a strategy of clinical examination, biochemical analysis of urine samples, enzyme tests and genetic characterization of underlying mutations. New techniques were developed, including analysis of urinary glycosaminoglycans with tandem mass spectrometry, miniaturized enzyme tests or novel synthetic substrates for enzyme assays using mass spectrometry detection of products using dried blood spots. Feasibility and cost-effectiveness of these methods in newborn screening programs have been demonstrated. Neuromuscular RDs, and especially familial amyloid polyneuropathy (FAP) were a topic of the Bulgarian colleagues. Diagnosis, screening and the role of microglia were also topics of particular interest. In summary, this year RD meeting was exciting and productive on a wide range of diseases and on a novel insights on
FOREWORD: 4th International Workshop on New Computational Methods for Inverse Problems (NCMIP2014)
NASA Astrophysics Data System (ADS)
2014-10-01
This volume of Journal of Physics: Conference Series is dedicated to the scientific contributions presented during the 4th International Workshop on New Computational Methods for Inverse Problems, NCMIP 2014 (http://www.farman.ens-cachan.fr/NCMIP_2014.html). This workshop took place at Ecole Normale Supérieure de Cachan, on May 23, 2014. The prior editions of NCMIP also took place in Cachan, France, firstly within the scope of ValueTools Conference, in May 2011 (http://www.ncmip.org/2011/), and secondly at the initiative of Institut Farman, in May 2012 and May 2013, (http://www.farman.ens-cachan.fr/NCMIP_2012.html), (http://www.farman.ens-cachan.fr/NCMIP_2013.html). The New Computational Methods for Inverse Problems (NCMIP) Workshop focused on recent advances in the resolution of inverse problems. Indeed, inverse problems appear in numerous scientific areas such as geophysics, biological and medical imaging, material and structure characterization, electrical, mechanical and civil engineering, and finances. The resolution of inverse problems consists of estimating the parameters of the observed system or structure from data collected by an instrumental sensing or imaging device. Its success firstly requires the collection of relevant observation data. It also requires accurate models describing the physical interactions between the instrumental device and the observed system, as well as the intrinsic properties of the solution itself. Finally, it requires the design of robust, accurate and efficient inversion algorithms. Advanced sensor arrays and imaging devices provide high rate and high volume data; in this context, the efficient resolution of the inverse problem requires the joint development of new models and inversion methods, taking computational and implementation aspects into account. During this one-day workshop, researchers had the opportunity to bring to light and share new techniques and results in the field of inverse problems. The topics of the
4th Rare Disease South Eastern Europe (See) Meeting Skopje, Macedonia (November 14th, 2015).
Gucev, Zoran; Tasic, Velibor; Polenakovic, Momir
2015-01-01
The 4th meeting on rare diseases in South Eastern Europe (SEE) was held in Skopje, at the Macedonian Academy of Sciences and Arts (MASA) on the 14(th) of November 2015. The focuses were metabolic, rare brain diseases as well as the rare dysmorphic syndrome. The authors of the report are particularly keen on stating that one of the main goals of the meeting, namely to help the treatment of patients with rare disease has begun to bear fruits. The talk on an iminosugar-based pharmacological chaperone compound as a drug candidate for the treatment of GM1-gangliosidosis and mucopolysaccharidosis IVB (Morquio disease type B) was enlightening. To date, there is no treatment available to be offered to patients, but chaperones lead mutated proteins to adopt a native-like conformation and to successfully traffic to their normal cellular destination. DORPHAN is developing an iminosugar-based pharmacological chaperone compound for the treatment of GM1-gangliosidosis and mucopolysaccharidosis IVB. A talk on recent developments in the laboratory diagnosis of mucopolysaccharidoses (MPS) was particularly interesting, covering the laboratory diagnosis of the MPS diseases by a strategy of clinical examination, biochemical analysis of urine samples, enzyme tests and genetic characterization of underlying mutations. New techniques were developed, including analysis of urinary glycosaminoglycans with tandem mass spectrometry, miniaturized enzyme tests or novel synthetic substrates for enzyme assays using mass spectrometry detection of products using dried blood spots. Feasibility and cost-effectiveness of these methods in newborn screening programs have been demonstrated. Neuromuscular RDs, and especially familial amyloid polyneuropathy (FAP) were a topic of the Bulgarian colleagues. Diagnosis, screening and the role of microglia were also topics of particular interest. In summary, this year RD meeting was exciting and productive on a wide range of diseases and on a novel insights on
PREFACE: 4th Workshop on Theory, Modelling and Computational Methods for Semiconductors (TMCSIV)
NASA Astrophysics Data System (ADS)
Tomić, Stanko; Probert, Matt; Migliorato, Max; Pal, Joydeep
2014-06-01
These conference proceedings contain the written papers of the contributions presented at the 4th International Conference on Theory, Modelling and Computational Methods for Semiconductor materials and nanostructures. The conference was held at the MediaCityUK, University of Salford, Manchester, UK on 22-24 January 2014. The previous conferences in this series took place in 2012 at the University of Leeds, in 2010 at St William's College, York and in 2008 at the University of Manchester, UK. The development of high-performance computer architectures is finally allowing the routine use of accurate methods for calculating the structural, thermodynamic, vibrational, optical and electronic properties of semiconductors and their hetero- and nano-structures. The scope of this conference embraces modelling, theory and the use of sophisticated computational tools in semiconductor science and technology, where there is substantial potential for time-saving in R&D. Theoretical approaches represented in this meeting included: Density Functional Theory, Semi-empirical Electronic Structure Methods, Multi-scale Approaches, Modelling of PV devices, Electron Transport, and Graphene. Topics included, but were not limited to: Optical Properties of Quantum Nanostructures including Colloids and Nanotubes, Plasmonics, Magnetic Semiconductors, Photonic Structures, and Electronic Devices. This workshop ran for three days, with the objective of bringing together UK and international leading experts in the theoretical modelling of Group IV, III-V and II-VI semiconductors, as well as students, postdocs and early-career researchers. The first day focused on providing an introduction and overview of this vast field, aimed particularly at students, with several lectures given by recognized experts in various theoretical approaches. The following two days showcased some of the best theoretical research carried out in the UK in this field, with several contributions also from representatives of
Adler, Mark; Mangold, Karen; Trainor, Jennifer
2016-01-01
The transition from medical student to intern is a challenging process characterized by a steep learning curve. Focused courses targeting skills necessary for success as a resident have increased self-perceived preparedness, confidence, and medical knowledge. Our aim was to create a brief educational intervention for 4th-year medical students entering pediatric, family practice, and medicine/pediatric residencies to target skills necessary for an internship. The curriculum used a combination of didactic presentations, small group discussions, role-playing, facilitated debriefing, and simulation-based education. Participants completed an objective structured clinical exam requiring synthesis and application of multiple boot camp elements before and after the elective. Participants completed anonymous surveys assessing self-perceived preparedness for an internship, overall and in regards to specific skills, before the elective and after the course. Participants were asked to provide feedback about the course. Using checklists to assess performance, students showed an improvement in performing infant lumbar punctures (47.2% vs 77.0%; p < 0.01, 95% CI for the difference 0.2, 0.4%) and providing signout (2.5 vs. 3.9 (5-point scale) p < 0.01, 95% CI for the difference 0.6, 2.3). They did not show an improvement in communication with a parent. Participants demonstrated an increase in self-reported preparedness for all targeted skills, except for obtaining consults and interprofessional communication. There was no increase in reported overall preparedness. All participants agreed with the statements, “The facilitators presented the material in an effective manner,” “I took away ideas I plan to implement in internship,” and “I think all students should participate in a similar experience.” When asked to assess the usefulness of individual modules, all except order writing received a mean Likert score > 4. A focused boot camp addressing key knowledge and skills
Paradies, Yin
2006-01-01
Public health literature indicates that psychosocial stress is an important contributor to chronic disease development. However, there is scant research on the health effects of stress for minority groups, who suffer from a high burden of chronic disease. This paper provides a review of studies that examine the relationship between psychosocial stress and chronic disease for 4th world indigenous groups and African Americans. A total of 50 associational and 15 intervention studies fit the inclusion criteria for this review. A range of chronic diseases, as well as harmful health behaviors, were associated with psychosocial stress for indigenous peoples and African Americans, with much stronger findings for mental rather than physical health outcomes. Several stress moderating factors were also identified and a small body of intervention research suggests that transcendental meditation and group-oriented stress management may be effective in reducing psychosocial stress and its effects for African Americans and 4th world indigenous groups respectively.
Ji, Fuhai; Li, Jian; Fleming, Neal; Rose, David; Liu, Hong
2015-08-01
Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. We performed a prospective observational study to assess the effects of phenylephrine administration on CO values measured by the 3rd and 4th generation FloTrac algorithms. 54 patients were enrolled in this study. We used the Nexfin, a pulse contour method shown to be insensitive to vasopressor administration, as the reference method. Radial arterial pressures were recorded continuously in patients undergoing surgery. Phenylephrine administration times were documented. Arterial pressure recordings were subsequently analyzed offline using three different pulse contour analysis algorithms: FloTrac 3rd generation (G3), FloTrac 4th generation (G4), and Nexfin (nf). One minute of hemodynamic measurements was analyzed immediately before phenylephrine administration and then repeated when the mean arterial pressure peaked. A total of 157 (4.6 ± 3.2 per patient, range 1-15) paired sets of hemodynamic recordings were analyzed. Phenylephrine induced a significant increase in stroke volume (SV) and CO with the FloTrac G3, but not with FloTrac G4 or Nexfin algorithms. Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine.
R&W Club Frederick Hosts 4th Annual Golf Tournament Benefiting The Children’s Inn at NIH | Poster
The R&W Club Frederick’s 4th Annual Golf Tournament to benefit the Children’s Inn at NIH teed off on time despite cloudy weather and scattered showers. Employees from NCI at Frederick, the main NIH campus, and Leidos Biomed, along with family and friends, came to enjoy an afternoon at the beautiful Maryland National Golf Club in Middletown and to support a wonderful charity.
Morphometrical analysis of the human suprarenal gland between the 4th and 7th months of gestation.
Nowak, Dariusz; Góralczyk, Krzysztof; Zurada, Anna; Gielecki, Jerzy
2007-01-01
The present study's purpose has been to examine the development of the human suprarenal glands (SGs) during the prenatal period. Special attention was paid to sexual dimorphism and the differences between the parameters of the right and left SGs. Specimens were obtained from 187 human fetuses spontaneously aborted between the 4th and 7th months of gestation. The SGs were dissected from the fetuses after an immersion and preservation period of 3-24 months in 9% formalin solution. The mass and linear dimensions of each isolated SG were obtained, and these data revealed a progressive two-fold increase between the 4th and 7th months of gestation. There was a gradual reduction in the ratio of the SG mass to the overall mass of the fetus with a marked decrease evident between the 4th and 5th months. Statistical analysis of both SGs showed significant differences between sexes in the mass and in the thickness of the left SG during the 5th and 6th months of gestation. Differences in the mass and linear dimensions of the left and right SGs were recorded from the 5th month of gestation to the 7th month. The mass and volume of the left SGs were higher than those on the right side. This allometric analysis provides data from a large sample of human fetuses and will later aid in microscopic and ultrasonographic studies.
NASA Technical Reports Server (NTRS)
Shu, Chi-Wang
2000-01-01
This project is about the investigation of the development of the discontinuous Galerkin finite element methods, for general geometry and triangulations, for solving convection dominated problems, with applications to aeroacoustics. On the analysis side, we have studied the efficient and stable discontinuous Galerkin framework for small second derivative terms, for example in Navier-Stokes equations, and also for related equations such as the Hamilton-Jacobi equations. This is a truly local discontinuous formulation where derivatives are considered as new variables. On the applied side, we have implemented and tested the efficiency of different approaches numerically. Related issues in high order ENO and WENO finite difference methods and spectral methods have also been investigated. Jointly with Hu, we have presented a discontinuous Galerkin finite element method for solving the nonlinear Hamilton-Jacobi equations. This method is based on the RungeKutta discontinuous Galerkin finite element method for solving conservation laws. The method has the flexibility of treating complicated geometry by using arbitrary triangulation, can achieve high order accuracy with a local, compact stencil, and are suited for efficient parallel implementation. One and two dimensional numerical examples are given to illustrate the capability of the method. Jointly with Hu, we have constructed third and fourth order WENO schemes on two dimensional unstructured meshes (triangles) in the finite volume formulation. The third order schemes are based on a combination of linear polynomials with nonlinear weights, and the fourth order schemes are based on combination of quadratic polynomials with nonlinear weights. We have addressed several difficult issues associated with high order WENO schemes on unstructured mesh, including the choice of linear and nonlinear weights, what to do with negative weights, etc. Numerical examples are shown to demonstrate the accuracies and robustness of the
Sound Emission of Rotor Induced Deformations of Generator Casings
NASA Technical Reports Server (NTRS)
Polifke, W.; Mueller, B.; Yee, H. C.; Mansour, Nagi (Technical Monitor)
2001-01-01
The casing of large electrical generators can be deformed slightly by the rotor's magnetic field. The sound emission produced by these periodic deformations, which could possibly exceed guaranteed noise emission limits, is analysed analytically and numerically. From the deformation of the casing, the normal velocity of the generator's surface is computed. Taking into account the corresponding symmetry, an analytical solution for the acoustic pressure outside the generator is round in terms of the Hankel function of second order. The normal velocity or the generator surface provides the required boundary condition for the acoustic pressure and determines the magnitude of pressure oscillations. For the numerical simulation, the nonlinear 2D Euler equations are formulated In a perturbation form for low Mach number Computational Aeroacoustics (CAA). The spatial derivatives are discretized by the classical sixth-order central interior scheme and a third-order boundary scheme. Spurious high frequency oscillations are damped by a characteristic-based artificial compression method (ACM) filter. The time derivatives are approximated by the classical 4th-order Runge-Kutta method. The numerical results are In excellent agreement with the analytical solution.
77 FR 39172 - Safety Zone: Skagway Harbor, Skagway, AK for 4th of July Fireworks
Federal Register 2010, 2011, 2012, 2013, 2014
2012-07-02
... ``Search.'' They are also available for inspection or copying at the Docket Management Facility (M-30), U.S..., Chief of Waterways Management, U.S. Coast Guard Sector Juneau; telephone (907) 463-2468, email Patrick.A... executive orders. Regulatory Planning and Review This rule is not a significant regulatory action...
NASA Astrophysics Data System (ADS)
Neuhuber, G.; G. Neuhuber1, W. Klary1, A. Nitschke1, B. Thapa2, Chris Risden3, T. Crampton4, D. Zerga5
2011-12-01
The 4th Bore is a highway tunnel on California State Route 24 currently under construction. The 4th Bore is undertaken by the California State Department of Transportation (CALTRANS) and the Contra Costa County Transportation Commission (CCTC) to alleviate traffic congestion on SR24 connecting the cities of Oakland and Orinda in the San Francisco East Bay Area. The cost for the 4th Bore is estimated at $ 390.8 Mill. The 3,249 ft long 4th Bore tunnel will have excavated dimensions of approximately 40 ft height and 49 ft width. A total of 7 cross passages will run between the 3rd and the new 4th bore. Geology and Hydrogeology: The project is located in the Oakland Berkeley Hills of the SF Bay Area. The Caldecott Tunnels lie within the easterly assemblage of the Hayward fault zone province which consists of a sequence of sedimentary and volcanic rocks that accumulated in the interval between about 16 and 8.4 Ma (Miocene). The basal rocks of these Tertiary deposits consist of deep marine basin sediments of the Monterey Group. These rocks are overlain uncomfortably by an interbedded sequence of terrestrial sediments (Orinda Formation) and volcanic rocks (Moraga Formation). The Tertiary rocks have been folded into large amplitude, NW trending folds that are cut by N trending strike and slip faults. The SF Bay Region, which is crossed by 4 major faults (San Gregorio, San Andreas, Hayward, and Calaveras), is considered one of the more seismically active regions of the world. The active Hayward fault lies 0.9mi to the west of the Caldecott Tunnels and is the closest major fault to the project area. The tunnel is at the moment under top heading construction: West Portal (360ft) and East Portal (1,968.5ft). While major faults typically influence groundwater flow, characterization of such influences is extremely difficult because of the heterogeneity of the hydraulic systems and the different lithological parameters and influences. Four major inactive fault zones striking
Spectral Element Method for the Simulation of Unsteady Compressible Flows
NASA Technical Reports Server (NTRS)
Diosady, Laslo Tibor; Murman, Scott M.
2013-01-01
This work uses a discontinuous-Galerkin spectral-element method (DGSEM) to solve the compressible Navier-Stokes equations [1{3]. The inviscid ux is computed using the approximate Riemann solver of Roe [4]. The viscous fluxes are computed using the second form of Bassi and Rebay (BR2) [5] in a manner consistent with the spectral-element approximation. The method of lines with the classical 4th-order explicit Runge-Kutta scheme is used for time integration. Results for polynomial orders up to p = 15 (16th order) are presented. The code is parallelized using the Message Passing Interface (MPI). The computations presented in this work are performed using the Sandy Bridge nodes of the NASA Pleiades supercomputer at NASA Ames Research Center. Each Sandy Bridge node consists of 2 eight-core Intel Xeon E5-2670 processors with a clock speed of 2.6Ghz and 2GB per core memory. On a Sandy Bridge node the Tau Benchmark [6] runs in a time of 7.6s.
NASA Astrophysics Data System (ADS)
Shum, Ping; Tang, Ming L.; Qian, Yi; Gong, Yan D.
2005-01-01
The purpose of this paper is to use numerical simulations and experiments to investigate the SCG in HNLF and optimize the SCG according to the parameters of fiber and pump pulse. Complex temporal and spectral characteristics of supercontinuum generation are investigated in the zero-dispersion wavelength (ZDW) region of highly nonlinear fibers. The simulations are based on an extended nonlinear Schrödinger equation (NLSE), which is valid even in circumstances where the bandwidth of the SCG is of the same order as the central frequency of the input pulse, and includes higher order nonlinearity, dispersion and intrapulse stimulated Raman scattering. We developed a finite difference scheme incorporating modified 4-th order Runge-Kutta algorithm to solve the equation. We discuss the SCG by varying the parameters of input pulse, such as pulse width, peak power, and center wavelength, to explore the dynamics of SCG in normal and anomalous dispersion regions. An optimal approach for supercontinuum generation is proposed and proved by experiments and simulations. The measured and calculated spectra are compared and exhibit good qualitative agreements. Our works provide a useful approach to design a practical SC source by using the conventional HNLF and readily available low power fiber laser sources.
Nonlinear dynamics of a simplified engine-propeller system
NASA Astrophysics Data System (ADS)
Yu, S. D.; Warwick, S. A.; Zhang, X.
2009-07-01
This paper presents a procedure for studying dynamical behaviors of a simplified engine-propeller dynamical system consisting of a number of bodies of plane motions. The equation of motion of the complex system is obtained using the Lagrange equation and solved numerically using the 4th order Runge-Kutta method. Various simulations were performed to investigate the transient and steady state behaviors of the multiple body system while taking into consideration the engine pressure pulsations, nonlinear inertia of moving bodies, and nonlinear aerodynamic load. Sub-harmonics and super harmonics in the steady state responses for different power and propeller pitch settings are obtained using the fast Fourier transform. Numerical simulations indicate that the 1.5 order is the dominant order of harmonics in the steady state oscillatory motion of the crankshaft. The findings and procedure presented in the paper are useful to the aerospace industry in certifying reciprocating engines and propellers. The crankshaft oscillatory velocities obtained from the simplified rigid body model are in good agreement with the experimental data for a SAITO-450 engine and a SOLO propeller at a 6″ pitch setting.
Gregory, Louis
2014-12-02
This report satisfies the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office (NNSA/NFO) commitment to prepare a quarterly summary report of radioactive waste shipments to and from the Nevada National Security Site (NNSS) Radioactive Waste Management Complex (RWMC) at Area 5. There were no shipments sent for offsite treatment and returned to the NNSS this quarter. There was one shipment of two drums sent for offsite treatment and disposal. This report summarizes the 4th quarter of Fiscal Year (FY) 2014 low-level radioactive waste (LLW) and mixed low-level radioactive waste (MLLW) shipments. This report also includes annual summaries for FY 2014.
Injector Beam Dynamics for a High-Repetition Rate 4th-Generation Light Source
Papadopoulos, C. F.; Corlett, J.; Emma, P.; Filippetto, D.; Penn, G.; Qiang, J.; Reinsch, M.; Sannibale, F.; Steier, C.; Venturini, M.; Wells, R.
2013-05-20
We report on the beam dynamics studies and optimization methods for a high repetition rate (1 MHz) photoinjector based on a VHF normal conducting electron source. The simultaneous goals of beamcompression and reservation of 6-dimensional beam brightness have to be achieved in the injector, in order to accommodate a linac driven FEL light source. For this, a parallel, multiobjective optimization algorithm is used. We discuss the relative merits of different injector design points, as well as the constraints imposed on the beam dynamics by technical considerations such as the high repetition rate.
Idaho National Laboratory Quarterly Event Performance Analysis FY 2013 4th Quarter
Lisbeth A. Mitchell
2013-11-01
This report is published quarterly by the Idaho National Laboratory (INL) Performance Assurance Organization. The Department of Energy Occurrence Reporting and Processing System (ORPS) as prescribed in DOE Order 232.2 “Occurrence Reporting and Processing of Operations Information” requires a quarterly analysis of events, both reportable and not reportable for the previous twelve months. This report is the analysis of occurrence reports and deficiency reports (including not reportable events) identified at the Idaho National Laboratory (INL) during the period of October 2012 through September 2013.
Lessons Learned from Numerical Simulations of Interfacial Instabilities
NASA Astrophysics Data System (ADS)
Cook, Andrew
2015-11-01
Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM) and Kelvin-Helmholtz (KH) instabilities serve as efficient mixing mechanisms in a wide variety of flows, from supernovae to jet engines. Over the past decade, we have used the Miranda code to temporally integrate the multi-component Navier-Stokes equations at spatial resolutions up to 29 billion grid points. The code employs 10th-order compact schemes for spatial derivatives, combined with 4th-order Runge-Kutta time advancement. Some of our major findings are as follows: The rate of growth of a mixing layer is equivalent to the net mass flux through the equi-molar plane. RT growth rates can be significantly reduced by adding shear. RT instability can produce shock waves. The growth rate of RM instability can be predicted from known interfacial perturbations. RM vortex projectiles can far outrun the mixing region. Thermal fluctuations in molecular dynamics simulations can seed instabilities along the braids in KH instability. And finally, enthalpy diffusion is essential in preserving the second law of thermodynamics. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Noisy contact interactions of multi-layer mechanical structures coupled by boundary conditions
NASA Astrophysics Data System (ADS)
Awrejcewicz, J.; Krysko, V. A., Jr.; Yakovleva, T. V.; Krysko, V. A.
2016-05-01
In this work mathematical models of temporal part of chaos at chosen spatial locations of a plate locally reinforced by ribs taking into account an interplay of their interactions are derived and studied numerically for the most relevant dynamical parameters. In addition, an influence of the additive external noise on chaotic vibrations of multi-layer beam-plate structures coupled only by boundary conditions is investigated. We illustrate and discuss novel nonlinear phenomena of the temporal regular and chaotic contact/no-contact dynamics with the help of Morlet wavelets and Fourier analysis. We show how the additive white noise cancels deterministic chaos close to the boundary of chaotic region in the space of parameters, and we present windows of on/off switching of the frequencies during the contact dynamics between structural members. In order to solve the mentioned design type nonlinear problem we apply methods of qualitative theory of differential equations, the Bubnov-Galerkin method in higher approximations, the Runge-Kutta methods of 4th, 6th and 8th order, as well as the computation and analysis of the largest Lyapunov exponent (Benettin's and Wolf's algorithms are used). The agreement of outcomes of all applied qualitatively different numerical approaches validate our simulation results. In particular, we have illustrated that the Fourier analysis of the studied mechanical structures may yield erroneous results, and hence the wavelet-based analysis is used to investigate chaotic dynamics in the system parameter space.
Modern tools for the time-discrete dynamics and optimization of gene-environment networks
NASA Astrophysics Data System (ADS)
Defterli, Ozlem; Fügenschuh, Armin; Weber, Gerhard Wilhelm
2011-12-01
In this study, we discuss the models of genetic regulatory systems, so-called gene-environment networks. The dynamics of such kind of systems are described by a class of time-continuous ordinary differential equations having a general form E˙=M(E)E, where E is a vector of gene-expression levels and environmental factors and M(E) is the matrix having functional entries containing unknown parameters to be optimized. Accordingly, time-discrete versions of that model class are studied and improved by introducing 3rd-order Heun's method and 4th-order classical Runge-Kutta method. The corresponding iteration formulas are derived and their matrix algebras are obtained. After that, we use nonlinear mixed-integer programming for the parameter estimation in the considered model and present the solution of a constrained and regularized given mixed-integer problem as an example. By using this solution and applying both the new and existing discretization schemes, we generate corresponding time-series of gene-expressions for each method. The comparison of the experimental data and the calculated approximate results is additionally done with the help of the figures to exercise the performance of the numerical schemes on this example.
NASA Astrophysics Data System (ADS)
DeJong, Andrew
Numerical models of fluid-structure interaction have grown in importance due to increasing interest in environmental energy harvesting, airfoil-gust interactions, and bio-inspired formation flying. Powered by increasingly powerful parallel computers, such models seek to explain the fundamental physics behind the complex, unsteady fluid-structure phenomena. To this end, a high-fidelity computational model based on the high-order spectral difference method on 3D unstructured, dynamic meshes has been developed. The spectral difference method constructs continuous solution fields within each element with a Riemann solver to compute the inviscid fluxes at the element interfaces and an averaging mechanism to compute the viscous fluxes. This method has shown promise in the past as a highly accurate, yet sufficiently fast method for solving unsteady viscous compressible flows. The solver is monolithically coupled to the equations of motion of an elastically mounted 3-degree of freedom rigid bluff body undergoing flow-induced lift, drag, and torque. The mesh is deformed using 4 methods: an analytic function, Laplace equation, biharmonic equation, and a bi-elliptic equation with variable diffusivity. This single system of equations -- fluid and structure -- is advanced through time using a 5-stage, 4th-order Runge-Kutta scheme. Message Passing Interface is used to run the coupled system in parallel on up to 240 processors. The solver is validated against previously published numerical and experimental data for an elastically mounted cylinder. The effect of adding an upstream body and inducing wake galloping is observed.
NASA Astrophysics Data System (ADS)
Liu, Y. Z.; Hao, Y. X.; Zhang, W.; Chen, J.; Li, S. B.
2015-07-01
The nonlinear vibration of a simply supported FGM cylindrical shell with small initial geometric imperfection under complex loads is studied. The effects of radial harmonic excitation, compressive in-plane force combined with supersonic aerodynamic and thermal loads are considered. The small initial geometric imperfection of the cylindrical shell is characterized in the form of the sine-type trigonometric functions. The effective material properties of this FGM cylindrical shell are graded in the radial direction according to a simple power law in terms of the volume fractions. Based on Reddy's third-order shear deformation theory, von Karman-type nonlinear kinematics and Hamilton's principle, the nonlinear partial differential equation that controls the shell dynamics is derived. Both axial symmetric and driven modes of the cylindrical shell deflection pattern are included. Furthermore, the equations of motion can be reduced into a set of coupled nonlinear ordinary differential equations by applying Galerkin's method. In the study of the nonlinear dynamics responses of small initial geometric imperfect FGM cylindrical shell under complex loads, the 4th order Runge-Kutta method is used to obtain time history, phase portraits, bifurcation diagrams and Poincare maps with different parameters. The effects of external loads, geometric imperfections and volume fractions on the nonlinear dynamics of the system are discussed.
Comparison of Fixed and Variable Time Step Trajectory Integration Methods for Cislunar Trajectories
NASA Technical Reports Server (NTRS)
Weeks, ichael W.; Thrasher, Stephen W.
2007-01-01
Due to the nonlinear nature of the Earth-Moon-Sun three-body problem and non-spherical gravity, CEV cislunar targeting algorithms will require many propagations in their search for a desired trajectory. For on-board targeting especially, the algorithm must have a simple, fast, and accurate propagator to calculate a trajectory with reasonable computation time, and still be robust enough to remain stable in the various flight regimes that the CEV will experience. This paper compares Cowell s method with a fourth-order Runge- Kutta integrator (RK4), Encke s method with a fourth-order Runge-Kutta- Nystr m integrator (RKN4), and a method known as Multi-Conic. Additionally, the study includes the Bond-Gottlieb 14-element method (BG14) and extends the investigation of Encke-Nystrom methods to integrators of higher order and with variable step size.
NASA Astrophysics Data System (ADS)
Zagidullin, Arthur; Petrova, Natalia
2016-07-01
In the present paper we construct equations describing the physical libration of the Moon ( PhLM). Consider a model the main problems, where, at this stage of development is taken into account only the second harmonic selenopotentsial. For the mathematical description of the problem, we use the construction of the Hamilton equations and their numerical solution. Since the equations describing the libration in latitude (at the level of kinetic energy) does not depend on the libration in longitude, we can divide the solution PhLM by longitude and by latitude. The fact that the equations for the longitude require special consideration of resonance in the Earth system: the Moon, which causes difficulty in the numerical integration of the corresponding equations for the longitude. To obtain latitudinal angles ρ and σ equations are integrated in view of the known analytical solutions for the longitude μ, resulting in analytical theory FLL Petrova (1996). Solution of the Hamilton system is implemented based on the Runge Kutta method of 4th order.
NASA Technical Reports Server (NTRS)
DeBonis, James R.
2013-01-01
A computational fluid dynamics code that solves the compressible Navier-Stokes equations was applied to the Taylor-Green vortex problem to examine the code s ability to accurately simulate the vortex decay and subsequent turbulence. The code, WRLES (Wave Resolving Large-Eddy Simulation), uses explicit central-differencing to compute the spatial derivatives and explicit Low Dispersion Runge-Kutta methods for the temporal discretization. The flow was first studied and characterized using Bogey & Bailley s 13-point dispersion relation preserving (DRP) scheme. The kinetic energy dissipation rate, computed both directly and from the enstrophy field, vorticity contours, and the energy spectra are examined. Results are in excellent agreement with a reference solution obtained using a spectral method and provide insight into computations of turbulent flows. In addition the following studies were performed: a comparison of 4th-, 8th-, 12th- and DRP spatial differencing schemes, the effect of the solution filtering on the results, the effect of large-eddy simulation sub-grid scale models, and the effect of high-order discretization of the viscous terms.
Quasi-integrable deformations of the SU(3) Affine Toda theory
NASA Astrophysics Data System (ADS)
Ferreira, L. A.; Klimas, P.; Zakrzewski, Wojtek J.
2016-05-01
We consider deformations of the SU(3) Affine Toda theory (AT) and investigate the integrability properties of the deformed theories. We find that for some special deformations all conserved quantities change to being conserved only asymptotically, i.e. in the process of the scattering of two solitons these charges do vary in time, but they return, after the scattering, to the values they had prior to the scattering. This phenomenon, which we have called quasi-integrability, is related to special properties of the two-soliton solutions under space-time parity transformations. Some properties of the AT solitons are discussed, especially those involving interesting static multi-soliton solutions. We support our analytical studies with detailed numerical ones in which the time evolution has been simulated by the 4th order Runge-Kutta method. We find that for some perturbations the solitons repel and for the others they form a quasi-bound state. When we send solitons towards each other they can repel when they come close together with or without `flipping' the fields of the model. The solitons radiate very little and appear to be stable. These results support the ideas of quasi-integrability, i.e. that many effects of integrability also approximately hold for the deformed models.
Nonstandard finite difference scheme for SIRS epidemic model with disease-related death
NASA Astrophysics Data System (ADS)
Fitriah, Z.; Suryanto, A.
2016-04-01
It is well known that SIRS epidemic with disease-related death can be described by a system of nonlinear ordinary differential equations (NL ODEs). This model has two equilibrium points where their existence and stability properties are determined by the basic reproduction number [1]. Besides the qualitative properties, it is also often needed to solve the system of NL ODEs. Euler method and 4th order Runge-Kutta (RK4) method are often used to solve the system of NL ODEs. However, both methods may produce inconsistent qualitative properties of the NL ODEs such as converging to wrong equilibrium point, etc. In this paper we apply non-standard finite difference (NSFD) scheme (see [2,3]) to approximate the solution of SIRS epidemic model with disease-related death. It is shown that the discrete system obtained by NSFD scheme is dynamically consistent with the continuous model. By our numerical simulations, we find that the solutions of NSFD scheme are always positive, bounded and convergent to the correct equilibrium point for any step size of integration (h), while those of Euler or RK4 method have the same properties only for relatively small h.
Mercuri, E G F; Daniel, A L; Hecke, M B; Carvalho, L
2016-09-01
This work represents a study of a mathematical model that describes the biological response to different mechanical stimuli in a cellular dynamics model for bone remodelling. The biological system discussed herein consists of three specialised cellular types, responsive osteoblasts, active osteoblasts and osteoclasts, three types of signalling molecules, transforming growth factor beta (TGF-β), receptor activator of nuclear factor kappa-b ligand (RANKL) and osteoprotegerin (OPG) and the parathyroid hormone (PTH). Three proposals for mechanical stimuli were tested: strain energy density (SED), hydrostatic and deviatoric parts of SED. The model was tested in a two-dimensional geometry of a standard human femur. The spatial discretization was performed by the finite element method while the temporal evolution of the variables was calculated by the 4th order Runge-Kutta method. The obtained results represent the temporal evolution of the apparent density distribution and the mean apparent density and thickness for the cortical bone after 600 days of remodelling simulation. The main contributions of this paper are the coupling of mechanical and biological models and the exploration of how the different mechanical stimuli affect the cellular activity in different types of physical activities. The results revealed that hydrostatic SED stimulus was able to form more cortical bone than deviatoric SED and total SED stimuli. The computational model confirms how different mechanical stimuli can impact in the balance of bone homeostasis.
Comparing heat exchangers of thermacoustic prime movers with a Van der Pol model
NASA Astrophysics Data System (ADS)
Cox, I.; Jorgensen, M.; Andersen, B.
2010-10-01
A thermoacoustic standing-wave prime mover is a self-sustained oscillator whose initial growth of acoustic pressure into amplitude saturation can be modeled by the Van der Pol equation. The nonlinear Van der Pol equation is calculated computationally, using 4^th order Runge-Kutta. The Van der Pol model gives quantitative loss and gain parameters, when using a best-fit with experimental data. The engines tested in this study have an average frequency of 2700 Hz, which suggests that the first second of oscillations when using the Van der Pol model can reveal information about the steady-state performance of the device. This model is applied to studying the effect of different heat exchanger sizes. All sixteen possible permutations were tested using different copper wire mesh dimensions: 24X24, 40X40, 60X60, and 80X80 for the hot and cold heat exchangers (where ##X## indicates wires per inch). Plotting the steady-state acoustic pressure as a function of the gain term divided by the loss term shows roughly, a linear relationship. The engine with the highest gain term and smallest loss term was using 80X80 for the hot heat exchanger combined with the 24X24 for the cold heat exchanger and is consistent with the highest steady-state pressure achieved. The modeling process has been very successful and fits the Van der Pol equation.
Time reversed test particle calculations at Titan, based on CAPS-IMS measurements
NASA Astrophysics Data System (ADS)
Bebesi, Zsofia; Erdos, Geza; Szego, Karoly; Young, David T.
2013-04-01
We used the theoretical approach of Kobel and Flückiger (1994) to construct a magnetic environment model in the vicinity of Titan - with the exception of placing the bow shock (which is not present at Titan) into infinity. The model has 4 free parameters to calibrate the shape and orientation of the field. We investigate the CAPS-IMS Singles data to calculate/estimate the location of origin of the detected cold ions at Titan, and we also use the measurements of the onboard Magnetometer to set the parameters of the model magnetic field. A 4th order Runge-Kutta method is applied to calculate the test particle trajectories in a time reversed scenario, in the curved magnetic environment. Several different ion species can be tracked by the model along their possible trajectories, as a first approach we considered three particle groups (1, 2 and 16 amu ions). In this initial study we show the results for some thoroughly discussed flybys like TA, TB and T5, but we consider more recent tailside encounters as well. Reference: Kobel, E. and E.O. Flückiger, A model of the steady state magnetic field in the magnetosheath, JGR 99, Issue A12, 23617, 1994
Additions and Improvements to the FLASH Code for Simulating High Energy Density Physics Experiments
NASA Astrophysics Data System (ADS)
Lamb, D. Q.; Daley, C.; Dubey, A.; Fatenejad, M.; Flocke, N.; Graziani, C.; Lee, D.; Tzeferacos, P.; Weide, K.
2015-11-01
FLASH is an open source, finite-volume Eulerian, spatially adaptive radiation hydrodynamics and magnetohydrodynamics code that incorporates capabilities for a broad range of physical processes, performs well on a wide range of computer architectures, and has a broad user base. Extensive capabilities have been added to FLASH to make it an open toolset for the academic high energy density physics (HEDP) community. We summarize these capabilities, with particular emphasis on recent additions and improvements. These include advancements in the optical ray tracing laser package, with methods such as bi-cubic 2D and tri-cubic 3D interpolation of electron number density, adaptive stepping and 2nd-, 3rd-, and 4th-order Runge-Kutta integration methods. Moreover, we showcase the simulated magnetic field diagnostic capabilities of the code, including induction coils, Faraday rotation, and proton radiography. We also describe several collaborations with the National Laboratories and the academic community in which FLASH has been used to simulate HEDP experiments. This work was supported in part at the University of Chicago by the DOE NNSA ASC through the Argonne Institute for Computing in Science under field work proposal 57789; and the NSF under grant PHY-0903997.
Numerical Simulation on Applicability of Resonant Magnetic Perturbation to KSTAR Tokamak
NASA Astrophysics Data System (ADS)
Kim, Doohyun; Han, Hyunsun; Kim, Ki Min; Hong, Sang Hee
2009-11-01
A numerical simulation is carried out to investigate the perturbed magnetic field configurations for a feasibility study on the resonant magnetic perturbation(RMP) to mitigate ELM damages to the divertor in KSTAR tokamak. The perturbed magnetic fields are described by vacuum superposition of equilibrium fields and fluctuating fields induced from the in- vessel control coils (IVCCs) will be installed in KSTAR. The equilibrium and induced fields are calculated using Grad- Shafranov equation and Biot-Savart law, respectively. For visualizing the magnetic field configurations, a field line tracing code has been developed using the 4th-order Runge-Kutta method. Magnetic field perturbations and island configurations can be found with this tracing code by describing poloidal positions of field lines as the increment of toroidal angle. And the Chirikov parameter is calculated to verify the generation of stochastic layer by overlap of magnetic islands. From this numerical work, it is confirmed that stochastic magnetic field lines are formed when the IVCC magnetic fields are generated, and the effect of RMP on KSTAR operation is discussed.
Xiong, Caiqiao; Zhou, Xiaoyu; Zhang, Ning; Zhan, Lingpeng; Chen, Yongtai; Nie, Zongxiu
2016-02-01
The nonlinear harmonics within the ion motion are the fingerprint of the nonlinear fields. They are exclusively introduced by these nonlinear fields and are responsible to some specific nonlinear effects such as nonlinear resonance effect. In this article, the ion motion in the quadrupole field with a weak superimposed octopole component, described by the nonlinear Mathieu equation (NME), was studied by using the analytical harmonic balance (HB) method. Good accuracy of the HB method, which was comparable with that of the numerical fourth-order Runge-Kutta (4th RK), was achieved in the entire first stability region, except for the points at the stability boundary (i.e., β = 1) and at the nonlinear resonance condition (i.e., β = 0.5). Using the HB method, the nonlinear 3β harmonic series introduced by the octopole component and the resultant nonlinear resonance effect were characterized. At nonlinear resonance, obvious resonant peaks were observed in the nonlinear 3β series of ion motion, but were not found in the natural harmonics. In addition, both resonant excitation and absorption peaks could be observed, simultaneously. These are two unique features of the nonlinear resonance, distinguishing it from the normal resonance. Finally, an approximation equation was given to describe the corresponding working parameter, q nr , at nonlinear resonance. This equation can help avoid the sensitivity degradation due to the operation of ion traps at the nonlinear resonance condition. PMID:26497312
Entropy generation analysis for film boiling: A simple model of quenching
NASA Astrophysics Data System (ADS)
Lotfi, Ali; Lakzian, Esmail
2016-04-01
In this paper, quenching in high-temperature materials processing is modeled as a superheated isothermal flat plate. In these phenomena, a liquid flows over the highly superheated surfaces for cooling. So the surface and the liquid are separated by the vapor layer that is formed because of the liquid which is in contact with the superheated surface. This is named forced film boiling. As an objective, the distribution of the entropy generation in the laminar forced film boiling is obtained by similarity solution for the first time in the quenching processes. The PDE governing differential equations of the laminar film boiling including continuity, momentum, and energy are reduced to ODE ones, and a dimensionless equation for entropy generation inside the liquid boundary and vapor layer is obtained. Then the ODEs are solved by applying the 4th-order Runge-Kutta method with a shooting procedure. Moreover, the Bejan number is used as a design criterion parameter for a qualitative study about the rate of cooling and the effects of plate speed are studied in the quenching processes. It is observed that for high speed of the plate the rate of cooling (heat transfer) is more.
Non-Darcy effect on boundary layer flow of TiO2-water/kerosene nanofluid over an extensible sheet
NASA Astrophysics Data System (ADS)
Tausif Sk, Md; Das, Kalidas; Kundu, Prabir Kumar
2016-09-01
An analytical and numerical enquiry has been executed to measure up to the numerical data and graphical figures of two different types of nanofluid boundary layer flow in a non-Darcy porous medium with TiO2 nanoparticles in the fluid. The current surface is continuously protracted under a fixed law and the base liquids are water and kerosene. A mathematical model of the stream has been developed and after renovating the non-linear partial differential equations into a system of ODE, it has been solved both analytically by Differential Transformation Method (DTM) in cooperation with Padé Approximant and numerically by Runge-Kutta 4th order shooting technique. The aggregate of the relations between various flow parameters with the skin friction and the heat transfer rate of two different fluids have been gauged by correlation coefficients and the impact of the relation has been verified using Fisher's t-Test. One of the most interesting verdicts of the progress survey is that the rate of heat transfer rate in the TiO2 -kerosene nanofluid is almost 83-88% higher than that of TiO2 -water nanofluid. Also the relation between various pertinent parameters with the Nusselt number and the skin friction coefficient are highly significant and they can be regulated according to our requirement by controlling these parameters of the flow.
Soot particle trajectories of a Di diesel engine at 18° ATDC crankshaft angle
NASA Astrophysics Data System (ADS)
Hafidzal, M. H. M.; Mahmood, W. M. F. W.; Manaf, M. Z. A.; Zakaria, M. S.; Saadun, M. N. A.; Nordin, M. N. A.
2013-12-01
Among the major pollutants of diesel engine is soot. Soot is formed as an unwelcome product in combustion systems. Soot emission to the atmosphere leads to global air warming and health problems. Furthermore, deposition of soot particles on cylinder walls contaminates lubricant oil hence increases its viscosity. This reduces durability of lubricant oil, causing pumpability problems and increasing wear. Therefore, it is necessary to study soot formation and its movement in diesel engines. This study focuses on soot particle trajectories in diesel engines by considering the diameter of soot particles that were formed at 18° ATDC crankshaft angle. These soot particle movements are under the influence of drag force with different radial, axial and angular settings and simulated by using MATLAB routine. The mathematical algorithm which was used in the MATLAB routine is trilinear interpolation and 4th order of Runge Kutta. Simulation was carried out for a combustion system of 4 valves DI diesel engine from inlet valve closing (IVC) to exhaust valve opening (EVO). The results show that small diameter of soot particles were transferred near the cylinder wall while bigger soot particle mostly moved in inner radius of the combustion chamber.
NASA Technical Reports Server (NTRS)
Liew, K. H.; Urip, E.; Yang, S. L.; Marek, C. J.
2004-01-01
Droplet interaction with a high temperature gaseous crossflow is important because of its wide application in systems involving two phase mixing such as in combustion requiring quick mixing of fuel and air with the reduction of pollutants and for jet mixing in the dilution zone of combustors. Therefore, the focus of this work is to investigate dispersion of a two-dimensional atomized and evaporating spray jet into a two-dimensional crossflow. An interactive Microsoft Excel program for tracking a single droplet in crossflow that has previously been developed will be modified to include droplet evaporation computation. In addition to the high velocity airflow, the injected droplets are also subjected to combustor temperature and pressure that affect their motion in the flow field. Six ordinary differential equations are then solved by 4th-order Runge-Kutta method using Microsoft Excel software. Microsoft Visual Basic programming and Microsoft Excel macrocode are used to produce the data and plot graphs describing the droplet's motion in the flow field. This program computes and plots the data sequentially without forcing the user to open other types of plotting programs. A user's manual on how to use the program is included.
A Hyperbolic Solver for Black Hole Initial Data in Numerical Relativity
NASA Astrophysics Data System (ADS)
Babiuc, Maria
2016-03-01
Numerical relativity is essential to the efforts of detecting gravitational waves emitted at the inspiral and merger of binary black holes. The first requirement for the generation of reliable gravitational wave templates is an accurate method of constructing initial data (ID). The standard approach is to solve the constraint equations for general relativity by formulating them as an elliptic system. A shortcoming of the ID constructed this way is an initial burst of spurious unphysical radiation (junk radiation). Recently, Racz and Winicour formulated the constraints as a hyperbolic problem, requiring boundary conditions only on a large sphere surrounding the system, where the physical behavior of the gravitational field is well understood. We investigate the applicability of this new approach, by developing a new 4th order numerical code that implements the fully nonlinear constraints equations on a two dimensional stereographic foliation, and evolves them radially inward using a Runge-Kutta integrator. The tensorial quantities are written as spin-weighted fields and the angular derivatives are replaced with ``eth'' operators. We present here results for the simulation of nonlinear perturbations to Schwarzschild ID in Kerr-Schild coordinates. The code shows stability and convergence at both large and small radii. Our long-term goal is to develop this new approach into a numerical scheme for generating ID for binary black holes and to analyze its performance in eliminating the junk radiation.
Frndak, Seth E.
2014-01-01
Background This ecological study examines the relationship between food desert prevalence and academic achievement at the school district level. Design and methods Sample included 232 suburban and urban school districts in New York State. Multiple open-source databases were merged to obtain: 4th grade science, English and math scores, school district demographic composition (NYS Report Card), regional socioeconomic indicators (American Community Survey), school district quality (US Common Core of Data), and food desert data (USDA Food Desert Atlas). Multiple regression models assessed the percentage of variation in achievement scores explained by food desert variables, after controlling for additional predictors. Results The proportion of individuals living in food deserts significantly explained 4th grade achievement scores, after accounting for additional predictors. School districts with higher proportions of individuals living in food desert regions demonstrated lower 4th grade achievement across science, English and math. Conclusions Food deserts appear to be related to academic achievement at the school district level among urban and suburban regions. Further research is needed to better understand how food access is associated with academic achievement at the individual level. Significance for public health The prevalence of food deserts in the United States is of national concern. As poor nutrition in United States children continues to spark debate, food deserts are being evaluated as potential sources of low fruit and vegetable intake and high obesity rates. Cognitive development and IQ have been linked to nutrition patterns, suggesting that children in food desert regions may have a disadvantage academically. This research evaluates if an ecological relationship between food desert prevalence and academic achievement at the school district level can be demonstrated. Results suggest that food desert prevalence may relate to poor academic performance at
Accurate time propagation method for the coupled Maxwell and Kohn-Sham equations
NASA Astrophysics Data System (ADS)
Li, Yonghui; He, Shenglai; Russakoff, Arthur; Varga, Kálmán
2016-08-01
An accurate method for time propagation of the coupled Maxwell and time-dependent Kohn-Sham (TDKS) equation is presented. The new approach uses a simultaneous fourth-order Runge-Kutta-based propagation of the vector potential and the Kohn-Sham orbitals. The approach is compared to the conventional fourth-order Taylor propagation and predictor-corrector methods. The calculations show several computational and numerical advantages, including higher computational performance, greater stability, better accuracy, and faster convergence.
Accurate time propagation method for the coupled Maxwell and Kohn-Sham equations.
Li, Yonghui; He, Shenglai; Russakoff, Arthur; Varga, Kálmán
2016-08-01
An accurate method for time propagation of the coupled Maxwell and time-dependent Kohn-Sham (TDKS) equation is presented. The new approach uses a simultaneous fourth-order Runge-Kutta-based propagation of the vector potential and the Kohn-Sham orbitals. The approach is compared to the conventional fourth-order Taylor propagation and predictor-corrector methods. The calculations show several computational and numerical advantages, including higher computational performance, greater stability, better accuracy, and faster convergence. PMID:27627419
Zakaria, Mohd Idzwan; Isa, Ridzuan Mohd; Shah Che Hamzah, Mohd Shaharudin; Ayob, Noor Azleen
2006-01-01
Medical standby is the provision of emergency medical care and first aid for participants and/or spectators in a pre-planned event. This article describes the framework and the demographics of a medical standby at the 4th National Youth Camping and Motivation Program in Pasir Puteh, Kelantan from 30th July until the 3rd August 2004. The framework of the medical team is described based on the work process of any medical stand by. A medical encounter form was created for the medical standby defining the type of case seen (medical or trauma), name, age, race and diagnosis of the patient. We concluded that interagency collaboration during the initial planning and during the event itself is needed to ensure the smooth running of the medical standby. Most of the medical encounters were minor illnesses which are similar to previous studies and there was no case transferred to the hospital during that period. PMID:22589590
Tapia, Richard
1998-06-01
In June, The Center for Research on Parallel Computation (CRPC), an NSF-funded Science and Technology Center, hosted the 4th Annual Conference for African-American Reserachers in the Mathematical Sciences (CAARMS4) at Rice University. The main goal of this conference was to highlight current work by African-American researchers and graduate students in mathematics. This conference strengthened the mathematical sciences by encouraging the increased participation of African-American and underrepresented groups into the field, facilitating working relationships between them and helping to cultivate their careers. In addition to the talks there was a graduate student poster session and tutorials on topics in mathematics and computer science. These talks, presentations, and discussions brought a broader perspective to the critical issues involving minority participation in mathematics.
Otto, D A; Skalik, I; House, D E; Hudnell, H K
1996-01-01
The Neurobehavioral Evaluation System was designed for field studies of workers, but many NES tests can be performed satisfactorily by children as young as 7 or 8 years old and a few tests, such as simple reaction time, can be performed by preschool children. However, little comparative data from children of different ages or grade levels are available. Studies of school children in the Czech Republic indicate that 2nd-grade children could perform the following NES tests satisfactorily: Finger Tapping, Visual Digit Span. Continuous Performance, Symbol-Digit Substitution, Pattern Comparison, and simpler conditions of Switching Attention. Comparative scores of boys and girls from the 2nd, 4th, and 8th grades and power analyses to estimate appropriate sample size were presented. Performance varied systematically with grade level and gender. Larger samples were needed with younger children to achieve comparable levels of statistical power. Gender comparisons indicated that boys responded faster, but made more errors than girls. PMID:8866533
Zakaria, Mohd Idzwan; Isa, Ridzuan Mohd; Shah Che Hamzah, Mohd Shaharudin; Ayob, Noor Azleen
2006-01-01
Medical standby is the provision of emergency medical care and first aid for participants and/or spectators in a pre-planned event. This article describes the framework and the demographics of a medical standby at the 4(th) National Youth Camping and Motivation Program in Pasir Puteh, Kelantan from 30(th) July until the 3(rd) August 2004. The framework of the medical team is described based on the work process of any medical stand by. A medical encounter form was created for the medical standby defining the type of case seen (medical or trauma), name, age, race and diagnosis of the patient. We concluded that interagency collaboration during the initial planning and during the event itself is needed to ensure the smooth running of the medical standby. Most of the medical encounters were minor illnesses which are similar to previous studies and there was no case transferred to the hospital during that period. PMID:22589590
MOWLAVI, Gholamreza; MAKKI, Mahsasadat; HEIDARI, Zahra; REZAEIAN, Mostafa; MOHEBALI, Mehdi; ARAUJO, Adauto; BOENKE, Nicole; AALI, Abolfazl; STOLLNER, Thomas; MOBEDI, Iraj
2015-01-01
Present paper is the second publication introducing the paleoparasitological findings from animal coprolites obtained from archeological site of Chehrabad salt mine in northwestern Iran. The current archeological site is located in northwest of Iran, dated to the Sassanian Era (4th/5th century CE). In the summer 2012 the carnivore coprolite was obtained within the layers in the mine and were thoroughly analyzed for parasites using TSP rehydration technique. Eggs of 0 were successfully retrieved from the examined coprolite and were confidently identified based on reliable references. Identifying of M. hirudinaceus eggs in paleofeces with clear appearance as demonstrated herein, is much due to appropriate preservation condition has been existed in the salt mine .The present finding could be regarded as the oldest acanthocephalan infection in Iran. PMID:26246822
2011-01-01
The aim of this study is to assess the prevalence, types, and trends of dietary supplement (DS) use. We analyzed the Dietary Supplement Questionnaire data of Korean aged 19 years old or older from the Nutrition Survey of the 4th Korea National Health and Nutrition Survey. Each reported DS was coded based on ingredients according to the 2010 Korean Food and Drug Administration Notification. The prevalence (standard error) of current DS use was 20.6% (0.7) for men, 32.2% (0.7) for women. Those with DS use for longer than two weeks during previous one year were 27.2% (0.7), and 40.2% (0.8), for men and women respectively. Vitamin mineral supplement (221.6/103 persons) was the most frequently consumed DS in Korean adults. The trend for DS use in Korean adults is changing as well as increasing. PMID:22745863
Asymptotic solution for heat convection-radiation equation
Mabood, Fazle; Ismail, Ahmad Izani Md; Khan, Waqar A.
2014-07-10
In this paper, we employ a new approximate analytical method called the optimal homotopy asymptotic method (OHAM) to solve steady state heat transfer problem in slabs. The heat transfer problem is modeled using nonlinear two-point boundary value problem. Using OHAM, we obtained the approximate analytical solution for dimensionless temperature with different values of a parameter ε. Further, the OHAM results for dimensionless temperature have been presented graphically and in tabular form. Comparison has been provided with existing results from the use of homotopy perturbation method, perturbation method and numerical method. For numerical results, we used Runge-Kutta Fehlberg fourth-fifth order method. It was found that OHAM produces better approximate analytical solutions than those which are obtained by homotopy perturbation and perturbation methods, in the sense of closer agreement with results obtained from the use of Runge-Kutta Fehlberg fourth-fifth order method.
Modeling of spray droplets deformation and breakup
NASA Technical Reports Server (NTRS)
Ibrahim, E. A.; Yang, H. Q.; Przekwas, A. J.
1993-01-01
A droplet deformation and breakup (DDB) model is proposed to study shear-type mechanism of spray droplets in pure extentional flows. A numerical solution of the DDB model equation is obtained using a fourth-order Runge-Kutta initial-value solver. The predictions of the DDB model as well as semianalytical and the Taylor analogy models are compared with the experimental data (Krzeczkowski, 1980) for shear breakup, which depict the dimensionless deformation of the drop vs dimensionless time.
A Discontinuous Galerkin Finite Element Method for Hamilton-Jacobi Equations
NASA Technical Reports Server (NTRS)
Hu, Changqing; Shu, Chi-Wang
1998-01-01
In this paper, we present a discontinuous Galerkin finite element method for solving the nonlinear Hamilton-Jacobi equations. This method is based on the Runge-Kutta discontinuous Galerkin finite element method for solving conservation laws. The method has the flexibility of treating complicated geometry by using arbitrary triangulation, can achieve high order accuracy with a local, compact stencil, and are suited for efficient parallel implementation. One and two dimensional numerical examples are given to illustrate the capability of the method.
Heat transfer in a micropolar fluid over a stretching sheet with Newtonian heating.
Qasim, Muhammad; Khan, Ilyas; Shafie, Sharidan
2013-01-01
This article looks at the steady flow of Micropolar fluid over a stretching surface with heat transfer in the presence of Newtonian heating. The relevant partial differential equations have been reduced to ordinary differential equations. The reduced ordinary differential equation system has been numerically solved by Runge-Kutta-Fehlberg fourth-fifth order method. Influence of different involved parameters on dimensionless velocity, microrotation and temperature is examined. An excellent agreement is found between the present and previous limiting results.
An approximation technique for jet impingement flow
Najafi, Mahmoud; Fincher, Donald; Rahni, Taeibi; Javadi, KH.; Massah, H.
2015-03-10
The analytical approximate solution of a non-linear jet impingement flow model will be demonstrated. We will show that this is an improvement over the series approximation obtained via the Adomian decomposition method, which is itself, a powerful method for analysing non-linear differential equations. The results of these approximations will be compared to the Runge-Kutta approximation in order to demonstrate their validity.
NASA Astrophysics Data System (ADS)
Khader, M. M.; Adel, M.
2016-09-01
In this paper, we implement the fractional complex transform method to convert the nonlinear fractional Klein-Gordon equation (FKGE) to an ordinary differential equation. We use the variational iteration method (VIM) to solve the resulting ODE. The fractional derivatives are presented in terms of the Caputo sense. Some numerical examples are presented to validate the proposed techniques. Finally, a comparison with the numerical solution using Runge-Kutta of order four is given.
NASA Technical Reports Server (NTRS)
Poole, L. R.
1972-01-01
A computer program is presented by which the effects of nonlinear suspension-system elastic characteristics on parachute inflation loads and motions can be investigated. A mathematical elastic model of suspension-system geometry is coupled to the planar equations of motion of a general vehicle and canopy. Canopy geometry and aerodynamic drag characteristics and suspension-system elastic properties are tabular inputs. The equations of motion are numerically integrated by use of an equivalent fifth-order Runge-Kutta technique.
NASA Astrophysics Data System (ADS)
Yang, Hongli; Wu, Xinyuan; Fang, Yonglei; You, Xiong
2008-09-01
In this paper, extended Runge-Kutta-Nyström type methods for perturbed oscillators with low frequency are presented, which inherit the framework of RKN method and make full use of the special feature of the true flows. Following the line of J.Butcher, E.Hairer and G.Wanner, we develop a new kind of trees to derive the order conditions for the new methods.
Quasi One-Dimensional Model of Natural Draft Wet-Cooling Tower Flow, Heat and Mass Transfer
NASA Astrophysics Data System (ADS)
Hyhlík, Tomáš
2015-05-01
The article deals with the development of CFD (Computational Fluid Dynamics) model of natural draft wet-cooling tower flow, heat and mass transfer. The moist air flow is described by the system of conservation laws along with additional equations. Moist air is assumed to be homogeneous mixture of dry air and water vapour. Liquid phase in the fill zone is described by the system of ordinary differential equations. Boundary value problem for the system of conservation laws is discretized in space using Kurganov-Tadmor central scheme and in time using strong stability preserving Runge-Kutta scheme. Initial value problems in the fill zone is solved by using standard fourth order Runge-Kutta scheme. The interaction between liquid water and moist air is done by source terms in governing equations.
NASA Technical Reports Server (NTRS)
Reed, K. W.; Stonesifer, R. B.; Atluri, S. N.
1983-01-01
A new hybrid-stress finite element algorith, suitable for analyses of large quasi-static deformations of inelastic solids, is presented. Principal variables in the formulation are the nominal stress-rate and spin. A such, a consistent reformulation of the constitutive equation is necessary, and is discussed. The finite element equations give rise to an initial value problem. Time integration has been accomplished by Euler and Runge-Kutta schemes and the superior accuracy of the higher order schemes is noted. In the course of integration of stress in time, it has been demonstrated that classical schemes such as Euler's and Runge-Kutta may lead to strong frame-dependence. As a remedy, modified integration schemes are proposed and the potential of the new schemes for suppressing frame dependence of numerically integrated stress is demonstrated. The topic of the development of valid creep fracture criteria is also addressed.
Snell, Laura M; Osokine, Ivan; Yamada, Douglas H; De la Fuente, Justin Rafael; Elsaesser, Heidi J; Brooks, David G
2016-09-20
Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection.
Snell, Laura M; Osokine, Ivan; Yamada, Douglas H; De la Fuente, Justin Rafael; Elsaesser, Heidi J; Brooks, David G
2016-09-20
Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection. PMID:27653690
A study of personality factors and interaction in 4th-year dental students and their teachers.
Watts, T L; Millard, L
1997-02-01
No previous investigation has considered dental student and teaching staff opinions on their relationship with each other. In a day when students are increasingly asked for feedback on the quality of teaching by staff, such investigations are of particular interest. This exploratory study was designed to compare the personality characteristics of a clinical year of dental students with those of the teaching staff they most frequently encountered, and to investigate these factors for possible associations with the quality of perceived teaching-learning interaction between the 2 groups. A complete 4th year of dental students (n = 87), and those teachers whom they met regularly (n = 80), were asked to participate. Subjects completed a form of the Myers-Briggs personality questionnaire simplified for use in education, and were asked to assess their relationship with persons in the other group. All the students and 75% of the staff, after follow-up, returned usable data. There was close similarity between staff and student personality profiles, and perception of working relationships by both groups was largely independent of personality factors and temperament. There were differences in staff perception of their relationship with extrovert and introvert students. Students showed minor differences in their perception of staff relationships with respect to two other personality factors. These findings indicate a substantial similarity between staff and students, and suggest a mature and stable relationship between people in the 2 groups. PMID:9567907
Chubar O.; Berman, L; Chu, Y.S.; Fluerasu, A.; Hulbert, S.; Idir, M.; Kaznatcheev, K.; Shapiro, D.; Baltser, J.
2012-04-04
Partially-coherent wavefront propagation calculations have proven to be feasible and very beneficial in the design of beamlines for 3rd and 4th generation Synchrotron Radiation (SR) sources. These types of calculations use the framework of classical electrodynamics for the description, on the same accuracy level, of the emission by relativistic electrons moving in magnetic fields of accelerators, and the propagation of the emitted radiation wavefronts through beamline optical elements. This enables accurate prediction of performance characteristics for beamlines exploiting high SR brightness and/or high spectral flux. Detailed analysis of radiation degree of coherence, offered by the partially-coherent wavefront propagation method, is of paramount importance for modern storage-ring based SR sources, which, thanks to extremely small sub-nanometer-level electron beam emittances, produce substantial portions of coherent flux in X-ray spectral range. We describe the general approach to partially-coherent SR wavefront propagation simulations and present examples of such simulations performed using 'Synchrotron Radiation Workshop' (SRW) code for the parameters of hard X-ray undulator based beamlines at the National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory. These examples illustrate general characteristics of partially-coherent undulator radiation beams in low-emittance SR sources, and demonstrate advantages of applying high-accuracy physical-optics simulations to the optimization and performance prediction of X-ray optical beamlines in these new sources.
Sayegh, Philip; Arentoft, Alyssa; Thaler, Nicholas S; Dean, Andy C; Thames, April D
2014-12-01
The current study examined whether self-rated education quality predicts Wide Range Achievement Test-4th Edition (WRAT-4) Word Reading subtest and neurocognitive performance, and aimed to establish this subtest's construct validity as an educational quality measure. In a community-based adult sample (N = 106), we tested whether education quality both increased the prediction of Word Reading scores beyond demographic variables and predicted global neurocognitive functioning after adjusting for WRAT-4. As expected, race/ethnicity and education predicted WRAT-4 reading performance. Hierarchical regression revealed that when including education quality, the amount of WRAT-4's explained variance increased significantly, with race/ethnicity and both education quality and years as significant predictors. Finally, WRAT-4 scores, but not education quality, predicted neurocognitive performance. Results support WRAT-4 Word Reading as a valid proxy measure for education quality and a key predictor of neurocognitive performance. Future research should examine these findings in larger, more diverse samples to determine their robust nature.
NASA Astrophysics Data System (ADS)
Gelmez Burakgazi, Sevinc; Yildirim, Ali; Weeth Feinstein, Noah
2016-04-01
Rooted in science education and science communication studies, this study examines 4th and 5th grade students' perceptions of science information sources (SIS) and their use in communicating science to students. It combines situated learning theory with uses and gratifications theory in a qualitative phenomenological analysis. Data were gathered through classroom observations and interviews in four Turkish elementary schools. Focus group interviews with 47 students and individual interviews with 17 teachers and 10 parents were conducted. Participants identified a wide range of SIS, including TV, magazines, newspapers, internet, peers, teachers, families, science centers/museums, science exhibitions, textbooks, science books, and science camps. Students reported using various SIS in school-based and non-school contexts to satisfy their cognitive, affective, personal, and social integrative needs. SIS were used for science courses, homework/project assignments, examination/test preparations, and individual science-related research. Students assessed SIS in terms of the perceived accessibility of the sources, the quality of the content, and the content presentation. In particular, some sources such as teachers, families, TV, science magazines, textbooks, and science centers/museums ("directive sources") predictably led students to other sources such as teachers, families, internet, and science books ("directed sources"). A small number of sources crossed context boundaries, being useful in both school and out. Results shed light on the connection between science education and science communication in terms of promoting science learning.
Springer, Andrew E; Lewis, Kayan; Kelder, Steven H; Fernandez, Maria E; Barroso, Cristina S; Hoelscher, Deanna M
2010-10-01
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed. We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004-2005 School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic (EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels, with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10) and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities in Spanish-speaking Hispanic children's PA participation. PMID:19365728
NASA Technical Reports Server (NTRS)
Lee-Rausch, Elizabeth M.; Hammond, Dana P.; Nielsen, Eric J.; Pirzadeh, S. Z.; Rumsey, Christopher L.
2010-01-01
FUN3D Navier-Stokes solutions were computed for the 4th AIAA Drag Prediction Workshop grid convergence study, downwash study, and Reynolds number study on a set of node-based mixed-element grids. All of the baseline tetrahedral grids were generated with the VGRID (developmental) advancing-layer and advancing-front grid generation software package following the gridding guidelines developed for the workshop. With maximum grid sizes exceeding 100 million nodes, the grid convergence study was particularly challenging for the node-based unstructured grid generators and flow solvers. At the time of the workshop, the super-fine grid with 105 million nodes and 600 million elements was the largest grid known to have been generated using VGRID. FUN3D Version 11.0 has a completely new pre- and post-processing paradigm that has been incorporated directly into the solver and functions entirely in a parallel, distributed memory environment. This feature allowed for practical pre-processing and solution times on the largest unstructured-grid size requested for the workshop. For the constant-lift grid convergence case, the convergence of total drag is approximately second-order on the finest three grids. The variation in total drag between the finest two grids is only 2 counts. At the finest grid levels, only small variations in wing and tail pressure distributions are seen with grid refinement. Similarly, a small wing side-of-body separation also shows little variation at the finest grid levels. Overall, the FUN3D results compare well with the structured-grid code CFL3D. The FUN3D downwash study and Reynolds number study results compare well with the range of results shown in the workshop presentations.
NASA Technical Reports Server (NTRS)
Lang, Stephen E.; Tao, Wei-Kuo; Chern, Jiun-Dar; Wu, Di; Li, Xiaowen
2015-01-01
Numerous cloud microphysical schemes designed for cloud and mesoscale models are currently in use, ranging from simple bulk to multi-moment, multi-class to explicit bin schemes. This study details the benefits of adding a 4th ice class (hail) to an already improved 3-class ice bulk microphysics scheme developed for the Goddard Cumulus Ensemble model based on Rutledge and Hobbs (1983,1984). Besides the addition and modification of several hail processes from Lin et al. (1983), further modifications were made to the 3-ice processes, including allowing greater ice super saturation and mitigating spurious evaporationsublimation in the saturation adjustment scheme, allowing graupelhail to become snow via vapor growth and hail to become graupel via riming, and the inclusion of a rain evaporation correction and vapor diffusivity factor. The improved 3-ice snowgraupel size-mapping schemes were adjusted to be more stable at higher mixing rations and to increase the aggregation effect for snow. A snow density mapping was also added. The new scheme was applied to an intense continental squall line and a weaker, loosely-organized continental case using three different hail intercepts. Peak simulated reflectivities agree well with radar for both the intense and weaker case and were better than earlier 3-ice versions when using a moderate and large intercept for hail, respectively. Simulated reflectivity distributions versus height were also improved versus radar in both cases compared to earlier 3-ice versions. The bin-based rain evaporation correction affected the squall line case more but did not change the overall agreement in reflectivity distributions.
Breakfast patterns among low-income, ethnically-diverse 4th-6th grade children in an urban area
2014-01-01
Background Increasing school breakfast participation has been advocated as a method to prevent childhood obesity. However, little is known about children’s breakfast patterns outside of school (e.g., home, corner store). Policies that increase school breakfast participation without an understanding of children’s breakfast habits outside of school may result in children consuming multiple breakfasts and may undermine efforts to prevent obesity. The aim of the current study was to describe morning food and drink consumption patterns among low-income, urban children and their associations with relative weight. Methods A cross-sectional analysis was conducted of data obtained from 651 4th-6th graders (51.7% female, 61.2% African American, 10.7 years) in 2012. Students completed surveys at school that included all foods eaten and their locations that morning. Height and weight were measured by trained research staff. Results On the day surveyed, 12.4% of youth reported not eating breakfast, 49.8% reported eating one breakfast, 25.5% reported eating two breakfasts, and 12.3% reported eating three or more breakfasts. The number of breakfasts consumed and BMI percentile showed a significant curvilinear relationship, with higher mean BMI percentiles observed among children who did not consume any breakfast and those who consumed ≥ 3 breakfasts. Sixth graders were significantly less likely to have consumed breakfast compared to younger children. A greater proportion of obese youth had no breakfast (18.0%) compared to healthy weight (10.1%) and overweight youth (10.7%, p = .01). Conclusions When promoting school breakfast, policies will need to be mindful of both over- and under-consumption to effectively address childhood obesity and food insecurity. Clinical trial registration NCT01924130 from http://clinicaltrials.gov/. PMID:24928474
NASA Astrophysics Data System (ADS)
Rennie, Adrian R.
2008-03-01
Approximately 700 delegates came to the small university city of Lund in southern Sweden at the end of June 2007 to attend the 4th European Conference on Neutron Scattering. The majority of these participants are primarily interested in specific areas of condensed matter science and use neutron techniques as a powerful tool to study the structure and dynamic behaviour of materials. These range from liquids, superconductors, magnetic materials and archaeological artefacts. The diversity of scientific problems is reflected by the attendance of many laboratories with specializations in numerous different disciplines. The maturity of the technique is shown by the fact that neutron scattering is now applied widely in so many areas. Most results from neutron scattering experiements are published as articles that primarily relate to a specific scientific discipline in the context of problem oriented research. The neutron scattering conference provided an opportunity to exchange ideas between different fields. It is hoped that this collection of papers, from participants that submitted articles on applications of neutron scattering, will continue to promote the exchange of ideas for new studies, as was seen at the conference. The papers that describe instrumentation and advances in methods of neutron scattering will appear separately in Measurement Science and Technology Worldwide activity in developing new facilities for neutron scattering and the motivation for substantial projects, such as the new target station at the ISIS facility in the UK or the proposed European Spallation Source, comes from unique information obtained from working with neutrons. The results reported in the following papers show that there is substantial exciting work still to be performed as the community of users expands into new fields. The participants, as well as the organizers, are extremely grateful to the numerous sponsors that helped to make the conference a resounding success. We are
ERIC Educational Resources Information Center
National Society for Autistic Children, Syracuse, NY.
Presented are proceedings of the 4th annual (1972) meeting of the National Society for Autistic Children including 11 papers given at the meeting. Listed are officers and board members of the society, the convention committee members, and recipients of citations and awards. The president's report notes past goals, accomplishments, and future…
ERIC Educational Resources Information Center
Portage Township Schools, IN.
An Indiana 310 Project was conducted to determine the needs of very low level adult basic education students (0-4th grade). Specifically, the study sought to answer the following four questions: (1) What brings low academic level students into ABE programs? (2) What aspects of the ABE programs do low academic level students dislike? (3) Why do low…
ERIC Educational Resources Information Center
Richardson, John C.
This paper presents a study regarding the correlation of the Stanford-Binet: 4th Edition Intelligence Quotient (IQ) scores with the Wechsler Adult Intelligence Scale-Revised (WAIS-R) IQ scores for the purpose of improving the identification process for educable mentally handicapped (EMH) school age adolescents and young adults. The sample included…
On December 2-3, 2015, the National Research Council (NRC) hosted the 4th meeting of the committee formed to peer review the draft IRIS assessment of inorganic arsenic. EPA presented background and overview materials during the public session on December 2nd. This information co...
ERIC Educational Resources Information Center
Bea, Jennifer W.; Martinez, Stephanie; Armstrong-Florian, Traci; Farrell, Vanessa; Martinez, Cathy; Whitmer, Evelyn; Hartz, Vern; Blake, Samuel; Nicolini, Ariana; Misner, Scottie
2014-01-01
Knowledge of U.S. dietary and physical activity recommendations and corresponding behaviors were surveyed among 4th and 5th graders in five Arizona counties to determine the need for related education in SNAP-Ed eligible schools. A <70% target response rate was the criterion. Participants correctly identified recommendations for: fruit, 20%;…
ERIC Educational Resources Information Center
Kilic, Abdurrahman
2012-01-01
In this study, the relationship of values in elementary school 4th grade Social Studies textbook with the attainments and their level of being included in student workbook are tried to be determined. Case study, which is a qualitative research method, was applied for this research. To collect data, document analysis technique, which is among the…
ERIC Educational Resources Information Center
Celikten, Oksan; Ipekcioglu, Sevgi; Ertepinar, Hamide; Geban, Omer
2012-01-01
The purpose of this study was to compare the effectiveness of the conceptual change oriented instruction through cooperative learning (CCICL) and traditional science instruction (TI) on 4th grade students' understanding of earth and sky concepts and their attitudes toward earth and sky concepts. In this study, 56 fourth grade students from the…
ERIC Educational Resources Information Center
Milman, Natalie B.; Carlson-Bancroft, Angela; Vanden Boogart, Amy
2014-01-01
This mixed methods case study examined the implementation of a 1:1 iPad initiative in a suburban, co-educational, independent, preK-4th grade elementary school in the United States. This article focuses on how teachers used iPads to differentiate instruction and across multiple content areas. Findings show the processes by which teachers employed…
ERIC Educational Resources Information Center
Online Submission, 2010
2010-01-01
The 4th international conference "Nation and Language: Modern Aspects of Socio-Linguistic Development" continues an eight-year old tradition. The conference is organized by Kaunas University of Technology Panevezys Institute and aims to bring scientists and researchers together for a general scientific discussion on new trends in sociolinguistic,…
NASA Astrophysics Data System (ADS)
Khalili, N.; Valliappan, S.; Li, Q.; Russell, A.
2010-07-01
The use for mathematical models of natural phenomena has underpinned science and engineering for centuries, but until the advent of modern computers and computational methods, the full utility of most of these models remained outside the reach of the engineering communities. Since World War II, advances in computational methods have transformed the way engineering and science is undertaken throughout the world. Today, theories of mechanics of solids and fluids, electromagnetism, heat transfer, plasma physics, and other scientific disciplines are implemented through computational methods in engineering analysis, design, manufacturing, and in studying broad classes of physical phenomena. The discipline concerned with the application of computational methods is now a key area of research, education, and application throughout the world. In the early 1980's, the International Association for Computational Mechanics (IACM) was founded to promote activities related to computational mechanics and has made impressive progress. The most important scientific event of IACM is the World Congress on Computational Mechanics. The first was held in Austin (USA) in 1986 and then in Stuttgart (Germany) in 1990, Chiba (Japan) in 1994, Buenos Aires (Argentina) in 1998, Vienna (Austria) in 2002, Beijing (China) in 2004, Los Angeles (USA) in 2006 and Venice, Italy; in 2008. The 9th World Congress on Computational Mechanics is held in conjunction with the 4th Asian Pacific Congress on Computational Mechanics under the auspices of Australian Association for Computational Mechanics (AACM), Asian Pacific Association for Computational Mechanics (APACM) and International Association for Computational Mechanics (IACM). The 1st Asian Pacific Congress was in Sydney (Australia) in 2001, then in Beijing (China) in 2004 and Kyoto (Japan) in 2007. The WCCM/APCOM 2010 publications consist of a printed book of abstracts given to delegates, along with 247 full length peer reviewed papers published with
NASA Astrophysics Data System (ADS)
Caplan, R. M.
2013-04-01
We present a simple to use, yet powerful code package called NLSEmagic to numerically integrate the nonlinear Schrödinger equation in one, two, and three dimensions. NLSEmagic is a high-order finite-difference code package which utilizes graphic processing unit (GPU) parallel architectures. The codes running on the GPU are many times faster than their serial counterparts, and are much cheaper to run than on standard parallel clusters. The codes are developed with usability and portability in mind, and therefore are written to interface with MATLAB utilizing custom GPU-enabled C codes with the MEX-compiler interface. The packages are freely distributed, including user manuals and set-up files. Catalogue identifier: AEOJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOJ_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 124453 No. of bytes in distributed program, including test data, etc.: 4728604 Distribution format: tar.gz Programming language: C, CUDA, MATLAB. Computer: PC, MAC. Operating system: Windows, MacOS, Linux. Has the code been vectorized or parallelized?: Yes. Number of processors used: Single CPU, number of GPU processors dependent on chosen GPU card (max is currently 3072 cores on GeForce GTX 690). Supplementary material: Setup guide, Installation guide. RAM: Highly dependent on dimensionality and grid size. For typical medium-large problem size in three dimensions, 4GB is sufficient. Keywords: Nonlinear Schröodinger Equation, GPU, high-order finite difference, Bose-Einstien condensates. Classification: 4.3, 7.7. Nature of problem: Integrate solutions of the time-dependent one-, two-, and three-dimensional cubic nonlinear Schrödinger equation. Solution method: The integrators utilize a fully-explicit fourth-order Runge-Kutta scheme in time
NASA Astrophysics Data System (ADS)
Balsara, Dinshaw S.; Amano, Takanobu; Garain, Sudip; Kim, Jinho
2016-08-01
collocation also ensures that electromagnetic radiation that is propagating in a vacuum has both electric and magnetic fields that are exactly divergence-free. Coupled relativistic fluid dynamic equations are solved for the positively and negatively charged fluids. The fluids' numerical fluxes also provide a self-consistent current density for the update of the electric field. Our reconstruction strategy ensures that fluid velocities always remain sub-luminal. Our third innovation consists of an efficient design for several popular IMEX schemes so that they provide strong coupling between the finite-volume-based fluid solver and the electromagnetic fields at high order. This innovation makes it possible to efficiently utilize high order IMEX time update methods for stiff source terms in the update of high order finite-volume methods for hyperbolic conservation laws. We also show that this very general innovation should extend seamlessly to Runge-Kutta discontinuous Galerkin methods. The IMEX schemes enable us to use large CFL numbers even in the presence of stiff source terms. Several accuracy analyses are presented showing that our method meets its design accuracy in the MHD limit as well as in the limit of electromagnetic wave propagation. Several stringent test problems are also presented. We also present a relativistic version of the GEM problem, which shows that our algorithm can successfully adapt to challenging problems in high energy astrophysics.
Something going on in Milan: a review of the 4th International PhD Student Cancer Conference
Segré, C
2010-01-01
The 4th International PhD Student Cancer Conference was held at the IFOM-IEO-Campus in Milan from 19–21 May 2010 http://www.semm.it/events_researchPast.php The Conference covered many topics related to cancer, from basic biology to clinical aspects of the disease. All attendees presented their research, by either giving a talk or presenting a poster. This conference is an opportunity to introduce PhD students to top cancer research institutes across Europe. The core participanting institutes included: European School of Molecular Medicine (SEMM)—IFOM-IEO Campus, MilanBeatson Institute for Cancer Research (BICR), GlasgowCambridge Research Institute (CRI), Cambridge, UKMRC Gray Institute of Radiation Biology (GIROB), OxfordLondon Research Institute (LRI), LondonPaterson Institute for Cancer Research (PICR), ManchesterThe Netherlands Cancer Institute (NKI), Amsterdam ‘You organizers have crushed all my prejudices towards Italians. Congratulations, I enjoyed the conference immensely!’ Even if it might have sounded like rudeness for sure this was supposed to be a genuine compliment (at least, that’s how we took it), also considering that it was told by a guy who himself was the fusion of two usually antithetical concepts: fashion style and English nationality. The year 2010 has marked an important event for Italian research in the international scientific panorama: the European School of Molecular Medicine (SEMM) had the honour to host the 4th International PhD Student Cancer Conference, which was held from 19–21 May 2010 at the IFOM-IEO-Campus (http://www.semm.it/events_researchPast.php) in Milan. The conference was attended by more than one hundred students, coming from a selection of cutting edge European institutes devoted to cancer research. The rationale behind it is the promotion of cooperation among young scientists across Europe to debate about science and to exchange ideas and experiences. But that is not all, it is also designed for PhD students
Something going on in Milan: a review of the 4th International PhD Student Cancer Conference.
Segré, C
2010-01-01
The 4th International PhD Student Cancer Conference was held at the IFOM-IEO-Campus in Milan from 19-21 May 2010 http://www.semm.it/events_researchPast.phpThe Conference covered many topics related to cancer, from basic biology to clinical aspects of the disease. All attendees presented their research, by either giving a talk or presenting a poster. This conference is an opportunity to introduce PhD students to top cancer research institutes across Europe.THE CORE PARTICIPANTING INSTITUTES INCLUDED: European School of Molecular Medicine (SEMM)-IFOM-IEO Campus, MilanBeatson Institute for Cancer Research (BICR), GlasgowCambridge Research Institute (CRI), Cambridge, UKMRC Gray Institute of Radiation Biology (GIROB), OxfordLondon Research Institute (LRI), LondonPaterson Institute for Cancer Research (PICR), ManchesterThe Netherlands Cancer Institute (NKI), Amsterdam'You organizers have crushed all my prejudices towards Italians. Congratulations, I enjoyed the conference immensely!' Even if it might have sounded like rudeness for sure this was supposed to be a genuine compliment (at least, that's how we took it), also considering that it was told by a guy who himself was the fusion of two usually antithetical concepts: fashion style and English nationality.The year 2010 has marked an important event for Italian research in the international scientific panorama: the European School of Molecular Medicine (SEMM) had the honour to host the 4th International PhD Student Cancer Conference, which was held from 19-21 May 2010 at the IFOM-IEO-Campus (http://www.semm.it/events_researchPast.php) in Milan.The conference was attended by more than one hundred students, coming from a selection of cutting edge European institutes devoted to cancer research. The rationale behind it is the promotion of cooperation among young scientists across Europe to debate about science and to exchange ideas and experiences. But that is not all, it is also designed for PhD students to get in touch
A Higher Order Perturbative Parton Evolution Toolkit (HOPPET)
NASA Astrophysics Data System (ADS)
Salam, G. P.; Rojo, J.
2009-01-01
This document describes a Fortran 95 package for carrying out DGLAP evolution and other common manipulations of parton distribution functions (PDFs). The PDFs are represented on a grid in x-space so as to avoid limitations on the functional form of input distributions. Good speed and accuracy are obtained through the representation of splitting functions in terms of their convolution with a set of piecewise polynomial basis functions, and Runge-Kutta techniques are used for the evolution in Q. Unpolarised evolution is provided to NNLO, including heavy-quark thresholds in the MS¯ scheme, and longitudinally polarised evolution to NLO. The code is structured so as to provide simple access to the objects representing splitting functions and PDFs, making it possible for a user to extend the facilities already provided. A streamlined interface is also available, facilitating use of the evolution part of the code from F77 and C/C++. Program summaryProgram title: HOPPET Catalogue identifier: AEBZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBZ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU Public License No. of lines in distributed program, including test data, etc.: 61 001 No. of bytes in distributed program, including test data, etc.: 270 312 Distribution format: tar.gz Programming language: Fortran 95 Computer: All Operating system: All RAM: ≲10 MB Classification: 11.5 Nature of problem: Solution of the DGLAP evolution equations up to NNLO (NLO) for unpolarised (longitudinally polarised) PDFs, and provision of tools to facilitate manipulation (convolutions, etc.) of PDFs with user-defined coefficient and splitting functions. Solution method: Representation of PDFs on a grid in x, adaptive integration of splitting functions to reduce them to a discretised form, obtaining fast convolutions that are equivalent to integration with an interpolated form of the PDFs; Runge-Kutta
Marsden, O; Bogey, C; Bailly, C
2014-03-01
The feasibility of using numerical simulation of fluid dynamics equations for the detailed description of long-range infrasound propagation in the atmosphere is investigated. The two dimensional (2D) Navier Stokes equations are solved via high fidelity spatial finite differences and Runge-Kutta time integration, coupled with a shock-capturing filter procedure allowing large amplitudes to be studied. The accuracy of acoustic prediction over long distances with this approach is first assessed in the linear regime thanks to two test cases featuring an acoustic source placed above a reflective ground in a homogeneous and weakly inhomogeneous medium, solved for a range of grid resolutions. An atmospheric model which can account for realistic features affecting acoustic propagation is then described. A 2D study of the effect of source amplitude on signals recorded at ground level at varying distances from the source is carried out. Modifications both in terms of waveforms and arrival times are described. PMID:24606252
NASA Astrophysics Data System (ADS)
Duru, Kenneth; Dunham, Eric M.
2016-01-01
Dynamic propagation of shear ruptures on a frictional interface in an elastic solid is a useful idealization of natural earthquakes. The conditions relating discontinuities in particle velocities across fault zones and tractions acting on the fault are often expressed as nonlinear friction laws. The corresponding initial boundary value problems are both numerically and computationally challenging. In addition, seismic waves generated by earthquake ruptures must be propagated for many wavelengths away from the fault. Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods. We present a high order accurate finite difference method for: a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration; b) dynamic propagation of earthquake ruptures along nonplanar faults; and c) accurate propagation of seismic waves in heterogeneous media with free surface topography. We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts (SBP) finite difference operators in space. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. The finite difference stencils used in this paper are sixth order accurate in the interior and third order accurate close to the boundaries. However, the method is applicable to any spatial operator with a diagonal norm satisfying the SBP property. Time stepping is performed with a 4th order accurate explicit low storage Runge-Kutta scheme, thus yielding a globally fourth order accurate method in both space and time. We show numerical simulations on band limited self-similar fractal faults revealing the complexity of rupture dynamics
NASA Astrophysics Data System (ADS)
Sventek, Joe
1998-12-01
Hewlett-Packard Laboratories, 1501 Page Mill Road, Palo Alto, CA 94304, USA Introduction The USENIX Conference on Object-Oriented Technologies and Systems (COOTS) is held annually in the late spring. The conference evolved from a set of C++ workshops that were held under the auspices of USENIX, the first of which met in 1989. Given the growing diverse interest in object-oriented technologies, the C++ focus of the workshop eventually became too narrow, with the result that the scope was widened in 1995 to include object-oriented technologies and systems. COOTS is intended to showcase advanced R&D efforts in object-oriented technologies and software systems. The conference emphasizes experimental research and experience gained by using object-oriented techniques and languages to build complex software systems that meet real-world needs. COOTS solicits papers in the following general areas: application of, and experiences with, object-oriented technologies in particular domains (e.g. financial, medical, telecommunication); the architecture and implementation of distributed object systems (e.g. CORBA, DCOM, RMI); object-oriented programming and specification languages; object-oriented design and analysis. The 4th meeting of COOTS was held 27 - 30 April 1998 at the El Dorado Hotel, Santa Fe, New Mexico, USA. Several tutorials were given. The technical program proper consisted of a single track of six sessions, with three paper presentations per session. A keynote address and a provocative panel session rounded out the technical program. The program committee reviewed 56 papers, selecting the best 18 for presentation in the technical sessions. While we solicit papers across the spectrum of applications of object-oriented technologies, this year there was a predominance of distributed, object-oriented papers. The accepted papers reflected this asymmetry, with 15 papers on distributed objects and 3 papers on object-oriented languages. The papers in this special issue are
NASA Astrophysics Data System (ADS)
Duru, K.; Dunham, E. M.; Bydlon, S. A.; Radhakrishnan, H.
2014-12-01
Dynamic propagation of shear ruptures on a frictional interface is a useful idealization of a natural earthquake.The conditions relating slip rate and fault shear strength are often expressed as nonlinear friction laws.The corresponding initial boundary value problems are both numerically and computationally challenging.In addition, seismic waves generated by earthquake ruptures must be propagated, far away from fault zones, to seismic stations and remote areas.Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods.We present a numerical method for:a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration;b) dynamic propagation of earthquake ruptures along rough faults; c) accurate propagation of seismic waves in heterogeneous media with free surface topography.We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts finite differences in space. The finite difference stencils are 6th order accurate in the interior and 3rd order accurate close to the boundaries. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. Time stepping is performed with a 4th order accurate explicit low storage Runge-Kutta scheme. We have performed extensive numerical experiments using a slip-weakening friction law on non-planar faults, including recent SCEC benchmark problems. We also show simulations on fractal faults revealing the complexity of rupture dynamics on rough faults. We are presently extending our method to rate-and-state friction laws and off-fault plasticity.
Bartůněk, Petr
2016-01-01
In 2015, the doctors and nurses of the 4th Department of Internal Medicine of the First Faculty of Medicine, Charles University and the General University Hospital in Prague celebrated the 70th anniversary of its founding. The article summarizes the clinics contribution to the field of internal medicine, and particularly to angiology, hepatogastroenterology and lipidology. It comments the clinics current activities and the possibilities of its further development. Attention is also paid to the tradition of high ethical and professional standards of medical care in accordance with the norms established by the clinic's founder, prof. MUDr. Bohumil Prusík.
Niebeling, H G; Fried, H; Goldhahn, W E; Skrzypczak, J; Brachmann, J; Eichler, I
1983-01-01
From a total of 1,028 infratentorial tumours operated on at the Neurosurgical Hospital of the Section Medicine of the Karl-Marx University Leipzig in the last 30 years, 167 tumours in the region of the 4th ventrical have been selected. Their statistical processing was carried out with respect to specific localisation, average age, kind of tumour, sex, clinical findings, duration of case history, application of instrumental diagnostic procedures and radicality of operation, success and failure. Some fundamental conclussions are drawn. A subdivision in detail will be contained in the following articles based on this material.
Darcy flow in heterogeneous porous media: relevance at sedimentary basin scale
NASA Astrophysics Data System (ADS)
Souche, Alban; Dabrowski, Marcin; Krotkiewski, Marcin
2010-05-01
Understanding heat transfer mechanisms in sedimentary rocks is important for recovering thermal history of sedimentary basins. Fluid flow may play a significant role by advecting heat within porous rocks of the basin. In extensional continental setting associated with stretching and thinning of the lithosphere, geothermal gradient below sedimentary basins may rise and contribute to the onset of thermal convection. Such process can be approximated by Darcy flow through porous media where thermal expansion introduces a gravitational instability between lighter hot fluids at the bottom and denser cold fluids at the top of the basin. However, the convection in such setting is inhibited by closing of the porosity with depth, which leads to limited amount of heat carrying fluids and a reduced permeability. We address this problem numerically by modeling Darcy's equations. To assess the accuracy of the pressure and velocity field in media with strongly varying permeability we compared two different numerical methods, 1) the standard finite element formulation with different order of elements (quadratic-pressure and linear-temperature) and 2) the mixed finite element formulation. An additional challenge in this study is to treat carefully the advection by choosing an appropriate numerical scheme. We used the method of characteristics with different flow integration, the Euler's and the 4th order Runge-Kutta's scheme, to avoid artificial diffusion that may significantly pollute the numerical solution. Results obtained for a homogeneous porous medium correspond to the analytical solution of the scaling between the Nusselt and Rayleigh numbers. We apply the tested model to investigate numerically the pattern of convection in heterogeneous porous rocks. We analyze the first-order characteristics and the limits of the convection in sedimentary basins under such conditions.
NASA Technical Reports Server (NTRS)
1981-01-01
Presentations of a conference on the use of ruggedized minicomputers are summarized. The following topics are discussed: (1) the role of minicomputers in the development and/or certification of commercial or military airplanes in both the United States and Europe; (2) generalized software error detection techniques; (3) real time software development tools; (4) a redundancy management research tool for aircraft navigation/flight control sensors; (5) extended memory management techniques using a high order language; and (6) some comments on establishing a system maintenance scheme. Copies of presentation slides are also included.
Latella, Giovanni; Rogler, Gerhard; Bamias, Giorgos; Breynaert, Christine; Florholmen, Jon; Pellino, Gianluca; Reif, Shimon; Speca, Silvia; Lawrance, Ian C
2014-10-01
The fourth scientific workshop of the European Crohn's and Colitis Organization (ECCO) focused on the relevance of intestinal fibrosis in the disease course of inflammatory bowel disease (IBD). The objective was to better understand the pathophysiological mechanisms of intestinal fibrosis, to identify useful markers and imaging modalities of fibrosis in order to assess its presence and progression, and, finally, to point out possible approaches for the prevention and the treatment of fibrosis. The results of this workshop are presented in three separate manuscripts. This first section describes the most important mechanisms that contribute to the initiation and progression of intestinal fibrosis in IBD including the cellular and molecular mediators, the extracellular matrix molecules and matrix metalloproteinases/tissue inhibitors of metalloproteinases-system, the microbiota products, the role of fat, genetic and epigenetic factors, as well as the currently available experimental models. Furthermore, it identifies unanswered questions in the field of intestinal fibrosis and provides a framework for future research.
NASA Astrophysics Data System (ADS)
Clarke, Joanne; Brooks, Nick; Banning, Edward B.; Bar-Matthews, Miryam; Campbell, Stuart; Clare, Lee; Cremaschi, Mauro; di Lernia, Savino; Drake, Nick; Gallinaro, Marina; Manning, Sturt; Nicoll, Kathleen; Philip, Graham; Rosen, Steve; Schoop, Ulf-Dietrich; Tafuri, Mary Anne; Weninger, Bernhard; Zerboni, Andrea
2016-03-01
This paper explores the possible links between rapid climate change (RCC) and social change in the Near East and surrounding regions (Anatolia, central Syria, southern Israel, Mesopotamia, Cyprus and eastern and central Sahara) during the 'long' 4th millennium (∼4500-3000) BC. Twenty terrestrial and 20 marine climate proxies are used to identify long-term trends in humidity involving transitions from humid to arid conditions and vice versa. The frequency distribution of episodes of relative aridity across these records is calculated for the period 6300-2000 BC, so that the results may be interpreted in the context of the established arid episodes associated with RCC around 6200 and 2200 BC (the 8.2 and 4.2 kyr events). We identify two distinct episodes of heightened aridity in the early-mid 4th, and late 4th millennium BC. These episodes cluster strongly at 3600-3700 and 3100-3300 BC. There is also evidence of localised aridity spikes in the 5th and 6th millennia BC. These results are used as context for the interpretation of regional and local archaeological records with a particular focus on case studies from western Syria, the middle Euphrates, southern Israel and Cyprus. Interpretation of the records involves the construction of plausible narratives of human-climate interaction informed by concepts of adaptation and resilience from the literature on contemporary (i.e. 21st century) climate change and adaptation. The results are presented alongside well-documented examples of climatically-influenced societal change in the central and eastern Sahara, where detailed geomorphological studies of ancient environments have been undertaken in tandem with archaeological research. While the narratives for the Near East and Eastern Mediterranean remain somewhat speculative, the use of resilience and adaptation frameworks allows for a more nuanced treatment of human-climate interactions and recognises the diversity and context-specificity of human responses to climatic
Analyzing and designing object-oriented missile simulations with concurrency
NASA Astrophysics Data System (ADS)
Randorf, Jeffrey Allen
2000-11-01
A software object model for the six degree-of-freedom missile modeling domain is presented. As a precursor, a domain analysis of the missile modeling domain was started, based on the Feature-Oriented Domain Analysis (FODA) technique described by the Software Engineering Institute (SEI). It was subsequently determined the FODA methodology is functionally equivalent to the Object Modeling Technique. The analysis used legacy software documentation and code from the ENDOSIM, KDEC, and TFrames 6-DOF modeling tools, including other technical literature. The SEI Object Connection Architecture (OCA) was the template for designing the object model. Three variants of the OCA were considered---a reference structure, a recursive structure, and a reference structure with augmentation for flight vehicle modeling. The reference OCA design option was chosen for maintaining simplicity while not compromising the expressive power of the OMT model. The missile architecture was then analyzed for potential areas of concurrent computing. It was shown how protected objects could be used for data passing between OCA object managers, allowing concurrent access without changing the OCA reference design intent or structure. The implementation language was the 1995 release of Ada. OCA software components were shown how to be expressed as Ada child packages. While acceleration of several low level and other high operations level are possible on proper hardware, there was a 33% degradation of 4th order Runge-Kutta integrator performance of two simultaneous ordinary differential equations using Ada tasking on a single processor machine. The Defense Department's High Level Architecture was introduced and explained in context with the OCA. It was shown the HLA and OCA were not mutually exclusive architectures, but complimentary. HLA was shown as an interoperability solution, with the OCA as an architectural vehicle for software reuse. Further directions for implementing a 6-DOF missile modeling
DUKSUP: A Computer Program for High Thrust Launch Vehicle Trajectory Design and Optimization
NASA Technical Reports Server (NTRS)
Williams, C. H.; Spurlock, O. F.
2014-01-01
From the late 1960's through 1997, the leadership of NASA's Intermediate and Large class unmanned expendable launch vehicle projects resided at the NASA Lewis (now Glenn) Research Center (LeRC). One of LeRC's primary responsibilities --- trajectory design and performance analysis --- was accomplished by an internally-developed analytic three dimensional computer program called DUKSUP. Because of its Calculus of Variations-based optimization routine, this code was generally more capable of finding optimal solutions than its contemporaries. A derivation of optimal control using the Calculus of Variations is summarized including transversality, intermediate, and final conditions. The two point boundary value problem is explained. A brief summary of the code's operation is provided, including iteration via the Newton-Raphson scheme and integration of variational and motion equations via a 4th order Runge-Kutta scheme. Main subroutines are discussed. The history of the LeRC trajectory design efforts in the early 1960's is explained within the context of supporting the Centaur upper stage program. How the code was constructed based on the operation of the Atlas/Centaur launch vehicle, the limits of the computers of that era, the limits of the computer programming languages, and the missions it supported are discussed. The vehicles DUKSUP supported (Atlas/Centaur, Titan/Centaur, and Shuttle/Centaur) are briefly described. The types of missions, including Earth orbital and interplanetary, are described. The roles of flight constraints and their impact on launch operations are detailed (such as jettisoning hardware on heating, Range Safety, ground station tracking, and elliptical parking orbits). The computer main frames on which the code was hosted are described. The applications of the code are detailed, including independent check of contractor analysis, benchmarking, leading edge analysis, and vehicle performance improvement assessments. Several of DUKSUP's many major
DUKSUP: A Computer Program for High Thrust Launch Vehicle Trajectory Design and Optimization
NASA Technical Reports Server (NTRS)
Spurlock, O. Frank; Williams, Craig H.
2015-01-01
From the late 1960s through 1997, the leadership of NASAs Intermediate and Large class unmanned expendable launch vehicle projects resided at the NASA Lewis (now Glenn) Research Center (LeRC). One of LeRCs primary responsibilities --- trajectory design and performance analysis --- was accomplished by an internally-developed analytic three dimensional computer program called DUKSUP. Because of its Calculus of Variations-based optimization routine, this code was generally more capable of finding optimal solutions than its contemporaries. A derivation of optimal control using the Calculus of Variations is summarized including transversality, intermediate, and final conditions. The two point boundary value problem is explained. A brief summary of the codes operation is provided, including iteration via the Newton-Raphson scheme and integration of variational and motion equations via a 4th order Runge-Kutta scheme. Main subroutines are discussed. The history of the LeRC trajectory design efforts in the early 1960s is explained within the context of supporting the Centaur upper stage program. How the code was constructed based on the operation of the AtlasCentaur launch vehicle, the limits of the computers of that era, the limits of the computer programming languages, and the missions it supported are discussed. The vehicles DUKSUP supported (AtlasCentaur, TitanCentaur, and ShuttleCentaur) are briefly described. The types of missions, including Earth orbital and interplanetary, are described. The roles of flight constraints and their impact on launch operations are detailed (such as jettisoning hardware on heating, Range Safety, ground station tracking, and elliptical parking orbits). The computer main frames on which the code was hosted are described. The applications of the code are detailed, including independent check of contractor analysis, benchmarking, leading edge analysis, and vehicle performance improvement assessments. Several of DUKSUPs many major impacts on
Gao, Na; Aono, Hikaru; Liu, Hao
2011-02-01
Insects exhibit exquisite control of their flapping flight, capable of performing precise stability and steering maneuverability. Here we develop an integrated computational model to investigate flight dynamics of insect hovering based on coupling the equations of 6 degree of freedom (6DoF) motion with the Navier-Stokes (NS) equations. Unsteady aerodynamics is resolved by using a biology-inspired dynamic flight simulator that integrates models of realistic wing-body morphology and kinematics, and a NS solver. We further develop a dynamic model to solve the rigid body equations of 6DoF motion by using a 4th-order Runge-Kutta method. In this model, instantaneous forces and moments based on the NS-solutions are represented in terms of Fourier series. With this model, we perform a systematic simulation-based analysis on the passive dynamic stability of a hovering fruit fly, Drosophila melanogaster, with a specific focus on responses of state variables to six one-directional perturbation conditions during latency period. Our results reveal that the flight dynamics of fruit fly hovering does not have a straightforward dynamic stability in a conventional sense that perturbations damp out in a manner of monotonous convergence. However, it is found to exist a transient interval containing an initial converging response observed for all the six perturbation variables and a terminal instability that at least one state variable subsequently tends to diverge after several wing beat cycles. Furthermore, our results illustrate that a fruit fly does have sufficient time to apply some active mediation to sustain a steady hovering before losing body attitudes. PMID:21093456
Fast discontinuous Galerkin lattice-Boltzmann simulations on GPUs via maximal kernel fusion
NASA Astrophysics Data System (ADS)
Mazzeo, Marco D.
2013-03-01
A GPU implementation of the discontinuous Galerkin lattice-Boltzmann method with square spectral elements, and highly optimised for speed and precision of calculations is presented. An extensive analysis of the numerous variants of the fluid solver unveils that best performance is obtained by maximising CUDA kernel fusion and by arranging the resulting kernel tasks so as to trigger memory coherent and scattered loads in a specific manner, albeit at the cost of introducing cross-thread load unbalancing. Surprisingly, any attempt to vanish this, to maximise thread occupancy and to adopt conventional work tiling or distinct custom kernels highly tuned via ad hoc data and computation layouts invariably deteriorate performance. As such, this work sheds light into the possibility to hide fetch latencies of workloads involving heterogeneous loads in a way that is more effective than what is achieved with frequently suggested techniques. When simulating the lid-driven cavity on a NVIDIA GeForce GTX 480 via a 5-stage 4th-order Runge-Kutta (RK) scheme, the first four digits of the obtained centreline velocity values, or more, converge to those of the state-of-the-art literature data at a simulation speed of 7.0G primitive variable updates per second during the collision stage and 4.4G ones during each RK step of the advection by employing double-precision arithmetic (DPA) and a computational grid of 642 4×4-point elements only. The new programming engine leads to about 2× performance w.r.t. the best programming guidelines in the field. The new fluid solver on the above GPU is also 20-30 times faster than a highly optimised version running on a single core of a Intel Xeon X5650 2.66 GHz.
Gas dynamics and heat transfer in a packed pebble-bed reactor for the 4th generation nuclear energy
NASA Astrophysics Data System (ADS)
Abdulmohsin, Rahman
-AlOx-Al junctions, we show that, despite excellent temperature stability, temperature fluctuations induce observable critical current fluctuations. Particularly, becuase 1/ f critical current noise has decreased with improved fabrication techniques in recent years, it is important to understand and eliminate this additional noise source. Next, we introduce a numerical method of calculating the mean square flux noise F2 from independently fluctuating spins on the surface of thin-film loops of arbitrary geometry. By reciprocity, F2 is proportional to Br2 , where B(r) is the magnetic field generated by a circulating current around the loop and r varies over the loop surface. By discretizing the loop nonuniformly, we efficiently and accurately compute the current distribution and resulting magnetic field, which may vary rapidly across the loop. We use this method to compute F2 in a number of scenarios in which we systematically vary physical parameters of the loop. We compare our simulations to an earlier analytic result predicting that F2 ∝ R/W in the limit where the loop radius R is much greater than the linewidth W. We further show that the previously neglected contribution of edge spins to F2 is significant---even dominant---in narrow-linewidth loops. To calculate theoretical dephasing rates in qubits, we consider flux noise with a spectral density Sphi( f) = A2/ (f/1 Hz) alpha, where A is of the order of 1 muphi 0 Hz--1/2 and 0.6 ≤ alpha ≤ 1.2; applied flux, our calculations of the dependence of the pure dephasing time tau φ Ramsey and echo pulse sequences on alpha for fixed A show that tauφ decreases rapidly as alpha is reduced. We find that tauφ is relatively insensitive to the noise bandwidth, f1 ≤ f ≤ f2 for all alpha provided the ultraviolet cutoff frequency f2 > 1/tauφ. We calculate the ratio tauφ,E/tau φ, R of the echo (E) and Ramsey (R) sequences, and the dependence of the decay function on alpha and f2. We investigate the case in which S phi(f0) is fixed
Abayomi, Olukayode; Amato, Davide; Bailey, Candace; Bitanihirwe, Byron; Bowen, Lynneice; Burshtein, Shimon; Cullen, Alexis; Fusté, Montserrat; Herrmann, Ana P; Khodaie, Babak; Kilian, Sanja; Lang, Qortni A; Manning, Elizabeth E; Massuda, Raffael; Nurjono, Milawaty; Sadiq, Sarosh; Sanchez-Gutierrez, Teresa; Sheinbaum, Tamara; Shivakumar, Venkataram; Simon, Nicholas; Spiteri-Staines, Anneliese; Sirijit, Suttajit; Toftdahl, Nanna Gilliam; Wadehra, Sunali; Wang, Yi; Wigton, Rebekah; Wright, Susan; Yagoda, Sergey; Zaytseva, Yuliya; O’Shea, Anne; DeLisi, Lynn E.
2015-01-01
The 4th Schizophrenia International Research Society Conference was held in Florence, Italy, April 5–9, 2014.and this year had as its emphasis, “Fostering Collaboration in Schizophrenia Research”. Student travel awardees served as rapporteurs for each oral session, summarized the important contributions of each session and then each report was integrated into a final summary of data discussed at the entire conference by topic. It is hoped that by combining data from different presentations, patterns of interest will emerge and thus lead to new progress for the future. In addition, the following report provides an overview of the conference for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research. PMID:25306204
Abayomi, Olukayode; Amato, Davide; Bailey, Candace; Bitanihirwe, Byron; Bowen, Lynneice; Burshtein, Shimon; Cullen, Alexis; Fusté, Montserrat; Herrmann, Ana P; Khodaie, Babak; Kilian, Sanja; Lang, Qortni A; Manning, Elizabeth E; Massuda, Raffael; Nurjono, Milawaty; Sadiq, Sarosh; Sanchez-Gutierrez, Teresa; Sheinbaum, Tamara; Shivakumar, Venkataram; Simon, Nicholas; Spiteri-Staines, Anneliese; Sirijit, Suttajit; Toftdahl, Nanna Gilliam; Wadehra, Sunali; Wang, Yi; Wigton, Rebekah; Wright, Susan; Yagoda, Sergey; Zaytseva, Yuliya; O'Shea, Anne; DeLisi, Lynn E
2014-11-01
The 4th Schizophrenia International Research Society Conference was held in Florence, Italy, April 5-9, 2014 and this year had as its emphasis, "Fostering Collaboration in Schizophrenia Research". Student travel awardees served as rapporteurs for each oral session, summarized the important contributions of each session and then each report was integrated into a final summary of data discussed at the entire conference by topic. It is hoped that by combining data from different presentations, patterns of interest will emerge and thus lead to new progress for the future. In addition, the following report provides an overview of the conference for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research.
Fowler, Daniel H.; Mossoba, Miriam E.; Steinberg, Seth M.; Halverson, David C.; Stroncek, David; Khuu, Hahn M.; Hakim, Frances T.; Castiello, Luciano; Sabatino, Marianna; Leitman, Susan F.; Mariotti, Jacopo; Gea-Banacloche, Juan C.; Sportes, Claude; Hardy, Nancy M.; Hickstein, Dennis D.; Pavletic, Steven Z.; Rowley, Scott; Goy, Andre; Donato, Michele; Korngold, Robert; Pecora, Andrew; Levine, Bruce L.; June, Carl H.; Gress, Ronald E.; Bishop, Michael R.
2013-01-01
In experimental models, ex vivo induced T-cell rapamycin resistance occurred independent of T helper 1 (Th1)/T helper 2 (Th2) differentiation and yielded allogeneic CD4+ T cells of increased in vivo efficacy that facilitated engraftment and permitted graft-versus-tumor effects while minimizing graft-versus-host disease (GVHD). To translate these findings, we performed a phase 2 multicenter clinical trial of rapamycin-resistant donor CD4+ Th2/Th1 (T-Rapa) cells after allogeneic-matched sibling donor hematopoietic cell transplantation (HCT) for therapy of refractory hematologic malignancy. T-Rapa cell products, which expressed a balanced Th2/Th1 phenotype, were administered as a preemptive donor lymphocyte infusion at day 14 post-HCT. After T-Rapa cell infusion, mixed donor/host chimerism rapidly converted, and there was preferential immune reconstitution with donor CD4+ Th2 and Th1 cells relative to regulatory T cells and CD8+ T cells. The cumulative incidence probability of acute GVHD was 20% and 40% at days 100 and 180 post-HCT, respectively. There was no transplant-related mortality. Eighteen of 40 patients (45%) remain in sustained complete remission (range of follow-up: 42-84 months). These results demonstrate the safety of this low-intensity transplant approach and the feasibility of subsequent randomized studies to compare T-Rapa cell-based therapy with standard transplantation regimens. This trial was registered at www.cancer.gov/clinicaltrials as #NCT 00077480. PMID:23426943
Deal, Alex L.; Erickson, Kristen J.; Shiers, Stephanie I.; Burman, Michael A.
2016-01-01
Classical fear conditioning creates an association between an aversive stimulus and a neutral stimulus. Although the requisite neural circuitry is well understood in mature organisms, the development of these circuits is less well studied. The current experiments examine the ontogeny of fear conditioning and relate it to neuronal activation assessed through immediate early gene (IEG) expression in the amygdala, hippocampus, perirhinal cortex, and hypothalamus of periweanling rats. Rat pups were fear conditioned, or not, during the 3rd or 4th weeks of life. Neuronal activation was assessed by quantifying expression of FBJ osteosarcoma oncogene (FOS) using immunohistochemistry (IHC) in Experiment 1. Fos and early growth response gene-1 (EGR1) expression was assessed using qRT-PCR in Experiment 2. Behavioral data confirm that both auditory and contextual fear continue to emerge between PD 17 and 24. The IEG expression data are highly consistent with these behavioral results. IHC results demonstrate significantly more FOS protein expression in the basal amygdala of fear conditioned PD 23 subjects compared to control subjects, but no significant difference at PD 17. qRT-PCR results suggest specific activation of the amygdala only in older subjects during auditory fear expression. A similar effect of age and conditioning status was also observed in the perirhinal cortex during both contextual and auditory fear expression. Overall, the development of fear conditioning occurring between the 3rd and 4th weeks of life appears to be at least partly attributable to changes in activation of the amygdala and perirhinal cortex during fear conditioning or expression. PMID:26820587
Early LLNL Application Scaling Results on BlueGene/L
Cook, A W; Greenough, J A; Gygi, F; Streitz, F H; Kubota, A; Bulatov, V V; Louis, S
2004-11-01
Miranda is a high order hydrodynamics code for computing fluid instabilities and turbulent mixing. It employs FFTs and band-diagonal matrix solvers for computing spectrally-accurate derivatives, combined with high-order integration methods for time advancement; e.g., fourth-order Runge-Kutta. Fluid properties, i.e., viscosity, diffusivity and thermal conductivity, are computed from kinetic theory. The code contains solvers for both compressible and incompressible flows. It has been used primarily for studying Rayleigh-Taylor (R-T) and Richtmyer-Meshkov (R-M) instabilities, which occur in supernovae and Inertial Confinement Fusion (ICF).
RAM: a Relativistic Adaptive Mesh Refinement Hydrodynamics Code
Zhang, Wei-Qun; MacFadyen, Andrew I.; /Princeton, Inst. Advanced Study
2005-06-06
The authors have developed a new computer code, RAM, to solve the conservative equations of special relativistic hydrodynamics (SRHD) using adaptive mesh refinement (AMR) on parallel computers. They have implemented a characteristic-wise, finite difference, weighted essentially non-oscillatory (WENO) scheme using the full characteristic decomposition of the SRHD equations to achieve fifth-order accuracy in space. For time integration they use the method of lines with a third-order total variation diminishing (TVD) Runge-Kutta scheme. They have also implemented fourth and fifth order Runge-Kutta time integration schemes for comparison. The implementation of AMR and parallelization is based on the FLASH code. RAM is modular and includes the capability to easily swap hydrodynamics solvers, reconstruction methods and physics modules. In addition to WENO they have implemented a finite volume module with the piecewise parabolic method (PPM) for reconstruction and the modified Marquina approximate Riemann solver to work with TVD Runge-Kutta time integration. They examine the difficulty of accurately simulating shear flows in numerical relativistic hydrodynamics codes. They show that under-resolved simulations of simple test problems with transverse velocity components produce incorrect results and demonstrate the ability of RAM to correctly solve these problems. RAM has been tested in one, two and three dimensions and in Cartesian, cylindrical and spherical coordinates. they have demonstrated fifth-order accuracy for WENO in one and two dimensions and performed detailed comparison with other schemes for which they show significantly lower convergence rates. Extensive testing is presented demonstrating the ability of RAM to address challenging open questions in relativistic astrophysics.
Optimal explicit strong-stability-preserving general linear methods : complete results.
Constantinescu, E. M.; Sandu, A.; Mathematics and Computer Science; Virginia Polytechnic Inst. and State Univ.
2009-03-03
This paper constructs strong-stability-preserving general linear time-stepping methods that are well suited for hyperbolic PDEs discretized by the method of lines. These methods generalize both Runge-Kutta (RK) and linear multistep schemes. They have high stage orders and hence are less susceptible than RK methods to order reduction from source terms or nonhomogeneous boundary conditions. A global optimization strategy is used to find the most efficient schemes that have low storage requirements. Numerical results illustrate the theoretical findings.
Optimal explicit strong-stability-preserving general linear methods.
Constantinescu, E.; Sandu, A.
2010-07-01
This paper constructs strong-stability-preserving general linear time-stepping methods that are well suited for hyperbolic PDEs discretized by the method of lines. These methods generalize both Runge-Kutta (RK) and linear multistep schemes. They have high stage orders and hence are less susceptible than RK methods to order reduction from source terms or nonhomogeneous boundary conditions. A global optimization strategy is used to find the most efficient schemes that have low storage requirements. Numerical results illustrate the theoretical findings.
Towards Robust Discontinuous Galerkin Methods for General Relativistic Neutrino Radiation Transport
NASA Astrophysics Data System (ADS)
Endeve, E.; Hauck, C. D.; Xing, Y.; Mezzacappa, A.
2015-10-01
With an eye towards simulating neutrino transport in core-collapse supernovae, we have developed a conservative, robust, and high-order numerical method for solving the general relativistic phase space advection problem in stationary spacetimes. The method achieves high-order accuracy using Discontinuous Galerkin discretization and Runge-Kutta time integration. For robustness, care is taken to ensure that the physical bounds on the phase space distribution function are preserved; i.e., f ∈ [0,1]. We briefly describe the bound-preserving scheme, and present results from numerical experiments in spherical symmetry adopting the Schwarzschild metric, which demonstrate that the method preserves the bounds on the distribution function.
Effect of membrane stiffening in transient impact analysis of composite laminated plates
NASA Astrophysics Data System (ADS)
Matsuhashi, Hiroto; Graves, Michael J.; Dugundji, John; Lagace, Paul A.
1993-04-01
An impacted plate response model was developed for composite laminated plates, based on energy equations derived by applying geometrical nonlinearity in strain-displacement relations, and using the Lagrangian equations of motion and the Rayleigh-Ritz method in conjunction with assumed mode shapes. The resulting system of second-order nonlinear differential equations with respect to time was solved using the fourth-order Runge-Kutta numerical time integration scheme, to produce a transient response in terms of force-time and displacement-time histories at the point of impact. A comparison of the analysis with the experimental data demonstrated good correlation, especially for the primary frequency response.
Computation of the modes and polar moment of inertial of the blades of an HAWT
NASA Technical Reports Server (NTRS)
Beaulieu, G.; Noiseux, D.
1981-01-01
The coupled differential equations of motion of the blades of a horizontal axis wind turbine are solved numerically, permitting the optimization of the design at relatively low cost. The equation of motion is transformed into a set of first order equations and solved with fourth order Runge-Kutta integrators. This technique is applied to a twisted, tapered blade of variable cross section and stiffness including discontinuities. The first six natural frequencies and mode shapes are obtained. The polar moment of inertia of the blades is obtained as a function of frequency and rotational speed.
Computation of the modes and polar moment of inertial of the blades of an HAWT
NASA Astrophysics Data System (ADS)
Beaulieu, G.; Noiseux, D.
1981-05-01
The coupled differential equations of motion of the blades of a horizontal axis wind turbine are solved numerically, permitting the optimization of the design at relatively low cost. The equation of motion is transformed into a set of first order equations and solved with fourth order Runge-Kutta integrators. This technique is applied to a twisted, tapered blade of variable cross section and stiffness including discontinuities. The first six natural frequencies and mode shapes are obtained. The polar moment of inertia of the blades is obtained as a function of frequency and rotational speed.
A parallel splitting wavelet method for 2D conservation laws
NASA Astrophysics Data System (ADS)
Schmidt, Alex A.; Kozakevicius, Alice J.; Jakobsson, Stefan
2016-06-01
The current work presents a parallel formulation using the MPI protocol for an adaptive high order finite difference scheme to solve 2D conservation laws. Adaptivity is achieved at each time iteration by the application of an interpolating wavelet transform in each space dimension. High order approximations for the numerical fluxes are computed by ENO and WENO schemes. Since time evolution is made by a TVD Runge-Kutta space splitting scheme, the problem is naturally suitable for parallelization. Numerical simulations and speedup results are presented for Euler equations in gas dynamics problems.
Flow Solver for Incompressible 2-D Drive Cavity
NASA Technical Reports Server (NTRS)
Kalb, Virginia L.
2008-01-01
This software solves the Navier-Stokes equations for the incompressible driven cavity flow problem. The code uses second-order finite differencing on a staggered grid using the Chorin projection method. The resulting intermediate Poisson equation is efficiently solved using the fast Fourier transform. Time stepping is done using fourth-order Runge-Kutta for stability at high Reynolds numbers. Features include check-pointing, periodic field snapshots, ongoing reporting of kinetic energy and changes between time steps, time histories at selected points, and optional streakline generation.
NASA Astrophysics Data System (ADS)
Wershow, H. N.; Green, M.; Stocker, A.; Staires, D.
2010-12-01
Current efforts towards Earth Science literacy in New Mexico are guided by the New Mexico Science Benchmarks [1]. We are geoscience professionals in Los Alamos, NM who believe there is an important role for non-traditional educators utilizing innovative teaching methods. We propose to further Earth Science literacy for local 3rd and 4th grade students using a kinesthetic learning approach, with the goal of fostering an interactive relationship between the students and their geologic environment. We will be working in partnership with the Pajarito Environmental Education Center (PEEC), which teaches the natural heritage of the Pajarito Plateau to 3rd and 4th grade students from the surrounding area, as well as the Family YMCA’s Adventure Programs Director. The Pajarito Plateau provides a remarkable geologic classroom because minimal structural features complicate the stratigraphy and dramatic volcanic and erosional processes are plainly on display and easily accessible. Our methodology consists of two approaches. First, we will build an interpretive display of the local geology at PEEC that will highlight prominent rock formations and geologic processes seen on a daily basis. It will include a simplified stratigraphic section with field specimens and a map linked to each specimen’s location to encourage further exploration. Second, we will develop and implement a kinesthetic curriculum for an exploratory field class. Active engagement with geologic phenomena will take place in many forms, such as a scavenger hunt for precipitated crystals in the vesicles of basalt flows and a search for progressively smaller rhyodacite clasts scattered along an actively eroding canyon. We believe students will be more receptive to origin explanations when they possess a piece of the story. Students will be provided with field books to make drawings of geologic features. This will encourage independent assessment of phenomena and introduce the skill of scientific observation. We
A SUNTANS-based unstructured grid local exact particle tracking model
NASA Astrophysics Data System (ADS)
Liu, Guangliang; Chua, Vivien P.
2016-07-01
A parallel particle tracking model, which employs the local exact integration method to achieve high accuracy, has been developed and embedded in an unstructured-grid coastal ocean model, Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator (SUNTANS). The particle tracking model is verified and compared with traditional numerical integration methods, such as Runge-Kutta fourth-order methods using several test cases. In two-dimensional linear steady rotating flow, the local exact particle tracking model is able to track particles along the circular streamline accurately, while Runge-Kutta fourth-order methods produce trajectories that deviate from the streamlines. In periodically varying double-gyre flow, the trajectories produced by local exact particle tracking model with time step of 1.0 × 10- 2 s are similar to those trajectories obtained from the numerical integration methods with reduced time steps of 1.0 × 10- 4 s. In three-dimensional steady Arnold-Beltrami-Childress (ABC) flow, the trajectories integrated with the local exact particle tracking model compares well with the approximated true path. The trajectories spiral upward and their projection on the x- y plane is a periodic ellipse. The trajectories derived with the Runge-Kutta fourth-order method deviate from the approximated true path, and their projections on the x- y plane are unclosed ellipses with growing long and short axes. The spatial temporal resolution needs to be carefully chosen before particle tracking models are applied. Our results show that the developed local exact particle tracking model is accurate and suitable for marine Lagrangian (trajectory-based)-related research.
On the Analysis of Multistep-Out-of-Grid Method for Celestial Mechanics Tasks
NASA Astrophysics Data System (ADS)
Olifer, L.; Choliy, V.
2016-09-01
Occasionally, there is a necessity in high-accurate prediction of celestial body trajectory. The most common way to do that is to solve Kepler's equation analytically or to use Runge-Kutta or Adams integrators to solve equation of motion numerically. For low-orbit satellites, there is a critical need in accounting geopotential and another forces which influence motion. As the result, the right side of equation of motion becomes much bigger, and classical integrators will not be quite effective. On the other hand, there is a multistep-out-of-grid (MOG) method which combines Runge-Kutta and Adams methods. The MOG method is based on using m on-grid values of the solution and n × m off-grid derivative estimations. Such method could provide stable integrators of maximum possible order, O (hm+mn+n-1). The main subject of this research was to implement and analyze the MOG method for solving satellite equation of motion with taking into account Earth geopotential model (ex. EGM2008 (Pavlis at al., 2008)) and with possibility to add other perturbations such as atmospheric drag or solar radiation pressure. Simulations were made for satellites on low orbit and with various eccentricities (from 0.1 to 0.9). Results of the MOG integrator were compared with results of Runge-Kutta and Adams integrators. It was shown that the MOG method has better accuracy than classical ones of the same order and less right-hand value estimations when is working on high orders. That gives it some advantage over "classical" methods.
NASA Astrophysics Data System (ADS)
Burger, E.; Bourgarit, D.; Wattiaux, A.; Fialin, M.
2010-09-01
From the end of Chalcolithic times (end of the 4th millennium BC) up to the end of the Bronze Age (1st millenium BC), copper production increases dramatically in Western Europe. However, due to the scarcity of technology-related archaeological data, the technological background sustaining the transition to mass production modes remains poorly understood. The main archaeological clues concerning metal production stem from the metallurgical waste, namely copper slags. Those complex materials may be a genuine chemical footprint of the process. In particular, it may bring new insights on one main issue of the process reconstruction: the origin of the oxygen in the system. A new analytical methodology based on both mass-balance calculation and quantification of Fe3+ contents in copper slags (Mössbauer spectroscopy, electronic microprobe and Synchrotron μ-XANES at the Fe-K-edge) has been set up. This methodology enables us to distinguish between the solid and gaseous sources of oxygen in a broad range of working conditions, thus yielding new features for the understanding of the first smelting processes dealing with copper sulphides in Western Europe 4000 years ago.
NASA Astrophysics Data System (ADS)
Demkin, V. A.; Zolotareva, B. N.; Demkina, T. S.; Khomutova, T. E.; Kashirskaya, N. N.; El'Tsov, M. V.; Udal'Tsov, S. N.
2012-02-01
Paleosols buried under kurgans of the Early (2nd-1st centuries BC), Middle (1st-2nd centuries AD) and Late (2nd-IV centuries AD) Sarmatian epochs were studied in dry steppes and desert steppes of the Lower Volga region (the Privolzhskaya and Ergeni Uplands and the Caspian Lowland). It was found that temporal variations in the morphological, chemical, microbiological, and magnetic properties of the paleosols in the interval of 2200-1600 BP were characterized by the cyclic pattern related to secular dynamics of climatic humidity with changes in the mean annual precipitation of ±30-50 mm. These climate changes did not transform chestnut paleosols and paleosolonetzes at the type or subtype taxonomic levels. However, they led to certain changes in the humus, carbonate, and salt profiles of the soils; in the character of solonetzic horizon B1; and in the state of microbial communities. According to these data, the Sarmatian time was characterized by alternation of micropluvial and microarid stages lasting fro about 100-200 years. In particular, the stages of humidization were observed in the 1st century BC-1st century AD and in the 4th century AD; the most arid conditions were observed in the second half of the 2nd and the first half of the 3rd century AD.
Preliminary Study on LiF4-ThF4-PuF4 Utilization as Fuel Salt of miniFUJI Molten Salt Reactor
NASA Astrophysics Data System (ADS)
Waris, Abdul; Aji, Indarta K.; Pramuditya, Syeilendra; Widayani; Irwanto, Dwi
2016-08-01
miniFUJI reactor is molten salt reactor (MSR) which is one type of the Generation IV nuclear energy systems. The original miniFUJI reactor design uses LiF-BeF2-ThF4-233UF4 as a fuel salt. In the present study, the use of LiF4-ThF4-PuF4 as fuel salt instead of LiF-BeF2-ThF4-UF4 will be discussed. The neutronics cell calculation has been performed by using PIJ (collision probability method code) routine of SRAC 2006 code, with the nuclear data library is JENDL-4.0. The results reveal that the reactor can attain the criticality condition with the plutonium concentration in the fuel salt is equal to 9.16% or more. The conversion ratio diminishes with the enlarging of plutonium concentration in the fuel. The neutron spectrum of miniFUJI MSR with plutonium fuel becomes harder compared to that of the 233U fuel.
NASA Astrophysics Data System (ADS)
Bedrina, T.; Parodi, A.; Quarati, A.; Clematis, A.; Rebora, N.; Laiosa, D.
2012-04-01
One of the critical issues in Hydro-Meteorological Research (HMR) is a better exploitation of data archives according to a multidisciplinary perspective. Different Earth science databases offer a huge amount of observational data, which often need to be assembled, processed, combined accordingly HM scientists needs. The cooperation between scientists active in HMR and Information and Communication Technologies (ICT) is essential in the development of innovative tools and applications for manipulating, aggregating and re-arranging heterogeneous information in flexible way. In this paper it is described an application devoted to the collection and integration of HM datasets, originated by public or private sources, freely exposed via Web services API. This application uses the mashup, recently become very popular in many fields, (Chow S.-W., 2007) technology concepts. Such methodology means combination of data and/or programs published by external online sources into an integrated experience. Mashup seems to be a promising methodology to respond to the multiple data-related activities into which HM researchers are daily involved (e.g. finding and retrieving high volume data; learning formats and developing readers; extracting parameters; performing filtering and mask; developing analysis and visualization tools). The specific case study of the recent extreme rainfall event, occurred over Genoa in Italy on the 4th November 2011 is shown through the integration of semi-professional weather observational networks as free available data source in addition to official weather networks.
Trull, Timothy J; Vergés, Alvaro; Wood, Phillip K; Jahng, Seungmin; Sher, Kenneth J
2012-10-01
We examined the latent structure underlying the criteria for DSM-IV-TR (American Psychiatric Association, 2000, Diagnostic and statistical manual of mental disorders (4th ed., text revision). Washington, DC: Author.) personality disorders in a large nationally representative sample of U.S. adults. Personality disorder symptom data were collected using a structured diagnostic interview from approximately 35,000 adults assessed over two waves of data collection in the National Epidemiologic Survey on Alcohol and Related Conditions. Our analyses suggested that a seven-factor solution provided the best fit for the data, and these factors were marked primarily by one or at most two personality disorder criteria sets. A series of regression analyses that used external validators tapping Axis I psychopathology, treatment for mental health problems, functioning scores, interpersonal conflict, and suicidal ideation and behavior provided support for the seven-factor solution. We discuss these findings in the context of previous studies that have examined the structure underlying the personality disorder criteria as well as the current proposals for DSM-5 personality disorders.
NASA Astrophysics Data System (ADS)
Russo Ermolli, Elda; Romano, Paola; Liuzza, Viviana; Amato, Vincenzo; Ruello, Maria Rosaria; Di Donato, Valentino
2014-05-01
Campania has always offered suitable climatic and physiographic conditions for human settlements since prehistoric times. In particular, many Graeco-Roman towns developed along its coasts starting from the 7th-6th cent. BC. In the last decade, geoarchaelogical surveys have been carried out in the archaeological excavations of Neapolis, Paestum and Elea-Velia allowing the main steps of the landscape evolution around these towns to be defined in detail. The greek town of Neapolis rose in the late 6th cent. BC [1] on a terrace overlooking a low-relief rocky coast surrounded by volcanic hills. Port activities developed in a protected bay facing the town from the 4th-2nd cent. BC up to the 4th cent. AD, as testified by the discovery of structures and shipwrecks [2, 3, 4]. Starting from the 3rd cent. AD a spit bar formed at the bay entrance causing the progressive establishment of a lagoon which was gradually filled up by alluvial inputs and completely closed in the 5th cent. AD. During the same period, episodes of increased alluvial inputs were also recorded further west along the coast, where a narrow sandy beach formed at the cliff toe. The greek town of Poseidonia, renamed Paestum by the Romans, was founded in the 540 BC on a travertine terrace facing the sandy littoral of a prograding coastal plain [5]. In front of the main town door, a coastal lagoon developed thanks to the growth of a dune ridge and was probably used for harbor activities [5]. After this period the shoreline shifted seawards, another dune ridge formed and the back-ridge depression was filled with fluvial-marshy deposits, slowly drying up. Phases of travertine deposition, which characterized the SE sector of the plain all along the Holocene, were recorded in the northern and southern quarters of the town in historical times and were connected to the abandonment of the town in the early Medieval times. The greek colony of Elea-Velia was located on top of a siliciclastic promontory where the ruins of
Swengel, Scott R; Swengel, Ann B
2016-01-01
Regal Fritillary (Speyeria idalia) primarily inhabits prairie, a native grassland of central North America, and occurs rarely in nonprairie grasslands further east. This butterfly has experienced widespread decline and marked range contraction. We analyze Regal Fritillary incidence and abundance during 1977-2014 in 4th of July Butterfly Counts, an annual census of butterflies in North America. Volunteers count within the same 24 km diameter circle each year. Only 6% of counts in range reported a Regal, while 18% of counts in core range in the Midwest and Great Plains did. 99.9% of Regal individuals occurred in core range. Only four circles east of core range reported this species, and only during the first half of the study period. All individuals reported west of its main range occurred in two circles in Colorado in the second half of the study. The number of counts per year and survey effort per count increased during the study. During 1991-2014, >31 counts occurred per year in core Regal range, compared to 0-23 during 1975-1990. During 1991-2014, all measures of Regal presence and abundance declined, most significantly. These results agree with other sources that Regal Fritillary has contracted its range and declined in abundance. PMID:27239370
2013-01-01
Recent insights into the genetic and somatic aberrations have initiated a new era of rapidly evolving targeted and immune-based treatments for melanoma. After decades of unsuccessful attempts to finding a more effective cure in the treatment of melanoma now we have several drugs active in melanoma. The possibility to use these drugs in combination to improve responses to overcome the resistance, to potentiate the action of immune system with the new immunomodulating antibodies, and identification of biomarkers that can predict the response to a particular therapy represent new concepts and approaches in the clinical management of melanoma. The third “Melanoma Research: “A bridge from Naples to the World” meeting, shortened as “Bridge Melanoma Meeting” took place in Naples, December 2 to 4th, 2012. The four topics of discussion at this meeting were: advances in molecular profiling and novel biomarkers, combination therapies, novel concepts toward integrating biomarkers and therapies into contemporary clinical management of patients with melanoma across the entire spectrum of disease stage, and the knowledge gained from the biology of tumor microenvironment across different tumors as a bridge to impact on prognosis and response to therapy in melanoma. This international congress gathered more than 30 international faculty members who in an interactive atmosphere which stimulated discussion and exchange of their experience regarding the most recent advances in research and clinical management of melanoma patients. PMID:23731854
Swengel, Scott R; Swengel, Ann B
2016-01-01
Regal Fritillary (Speyeria idalia) primarily inhabits prairie, a native grassland of central North America, and occurs rarely in nonprairie grasslands further east. This butterfly has experienced widespread decline and marked range contraction. We analyze Regal Fritillary incidence and abundance during 1977-2014 in 4th of July Butterfly Counts, an annual census of butterflies in North America. Volunteers count within the same 24 km diameter circle each year. Only 6% of counts in range reported a Regal, while 18% of counts in core range in the Midwest and Great Plains did. 99.9% of Regal individuals occurred in core range. Only four circles east of core range reported this species, and only during the first half of the study period. All individuals reported west of its main range occurred in two circles in Colorado in the second half of the study. The number of counts per year and survey effort per count increased during the study. During 1991-2014, >31 counts occurred per year in core Regal range, compared to 0-23 during 1975-1990. During 1991-2014, all measures of Regal presence and abundance declined, most significantly. These results agree with other sources that Regal Fritillary has contracted its range and declined in abundance.
2016-01-01
Regal Fritillary (Speyeria idalia) primarily inhabits prairie, a native grassland of central North America, and occurs rarely in nonprairie grasslands further east. This butterfly has experienced widespread decline and marked range contraction. We analyze Regal Fritillary incidence and abundance during 1977–2014 in 4th of July Butterfly Counts, an annual census of butterflies in North America. Volunteers count within the same 24 km diameter circle each year. Only 6% of counts in range reported a Regal, while 18% of counts in core range in the Midwest and Great Plains did. 99.9% of Regal individuals occurred in core range. Only four circles east of core range reported this species, and only during the first half of the study period. All individuals reported west of its main range occurred in two circles in Colorado in the second half of the study. The number of counts per year and survey effort per count increased during the study. During 1991–2014, >31 counts occurred per year in core Regal range, compared to 0–23 during 1975–1990. During 1991–2014, all measures of Regal presence and abundance declined, most significantly. These results agree with other sources that Regal Fritillary has contracted its range and declined in abundance. PMID:27239370
Central difference TVD schemes for time dependent and steady state problems
NASA Technical Reports Server (NTRS)
Jorgenson, P.; Turkel, E.
1993-01-01
A Runge-Kutta formula in time is presently used to advance schemes in which central differences are used to solve the time-dependent Euler equations; a second difference is added near shocks as an artificial viscosity to reduce the given scheme to a first-order upwind one at shocks. A matrix-valued dissipation is introduced and compared with the scalar viscosity; a connection is shown between this artificial viscosity and flux limiters. The use of various flux limiters for this central difference scheme is compared.
Central difference TVD schemes for time dependent and steady state problems
NASA Astrophysics Data System (ADS)
Jorgenson, P.; Turkel, E.
1993-08-01
A Runge-Kutta formula in time is presently used to advance schemes in which central differences are used to solve the time-dependent Euler equations; a second difference is added near shocks as an artificial viscosity to reduce the given scheme to a first-order upwind one at shocks. A matrix-valued dissipation is introduced and compared with the scalar viscosity; a connection is shown between this artificial viscosity and flux limiters. The use of various flux limiters for this central difference scheme is compared.
Taylor Series Trajectory Calculations Including Oblateness Effects and Variable Atmospheric Density
NASA Technical Reports Server (NTRS)
Scott, James R.
2011-01-01
Taylor series integration is implemented in NASA Glenn's Spacecraft N-body Analysis Program, and compared head-to-head with the code's existing 8th- order Runge-Kutta Fehlberg time integration scheme. This paper focuses on trajectory problems that include oblateness and/or variable atmospheric density. Taylor series is shown to be significantly faster and more accurate for oblateness problems up through a 4x4 field, with speedups ranging from a factor of 2 to 13. For problems with variable atmospheric density, speedups average 24 for atmospheric density alone, and average 1.6 to 8.2 when density and oblateness are combined.
Apollo experience report: Onboard navigational and alignment software
NASA Technical Reports Server (NTRS)
Savely, R. T.; Cockrell, B. F.; Pines, S.
1972-01-01
The onboard navigational and alignment routines used during the nonthrusting phases of an Apollo mission are discussed as to their limitations, and alternate approaches that have more desirable capabilities are presented. A more efficient procedure for solving Kepler's equation, which is used in the calculation of Kepler's problem and Lambert's problem is included, and a sixth-order predictor scheme with a Runge-Kutta starter is recommended for numerical integration. The extension of the rendezvous navigation state to include angle biases and the use of a fixed coordinate system is also evaluated.
A time domain, weighted residual formulation of Maxwell's equations
NASA Technical Reports Server (NTRS)
Young, Jeffrey L.; Brueckner, Frank P.
1993-01-01
A finite element model is developed and used to simulate two-dimensional electromagnetic wave propagation and scattering. The spatial discretization of the time-domain electrodynamic equations is accomplished by a Galerkin approach. The semi-discrete equations are solved explicitly using a second-order Runge-Kutta scheme. Both the electric and magnetic fields are discretized using a single grid, with the divergence-free conditions satisfied through a correction approach. Examples depicting the scattering of plane waves in 2D geometries are given to demonstrate the validity of the methodology.
NASA Astrophysics Data System (ADS)
Mustafa, M.; Khan, Junaid Ahmad
2015-07-01
Present work deals with the magneto-hydro-dynamic flow and heat transfer of Casson nanofluid over a non-linearly stretching sheet. Non-linear temperature distribution across the sheet is considered. More physically acceptable model of passively controlled wall nanoparticle volume fraction is accounted. The arising mathematical problem is governed by interesting parameters which include Casson fluid parameter, magnetic field parameter, power-law index, Brownian motion parameter, thermophoresis parameter, Prandtl number and Schmidt number. Numerical solutions are computed through fourth-fifth-order-Runge-Kutta integration approach combined with the shooting technique. Both temperature and nanoparticle volume fraction are increasing functions of Casson fluid parameter.
NASA Technical Reports Server (NTRS)
Yeh, H. Y.
1973-01-01
Studies are reported of the probability distribution of yield strength for mild steel, and the application of numerical techniques to solve mechanical vibration problems. Tensile experiments were conducted for 50 cold rolled and 38 hot rolled mild steel rods. Chi-square, Kolmogro-Smirnov and goodness-of-fit methods are used to test the normality or lognormality of the experimental results. As an example of the application of numerical techniques, a nonlinear dash-pot-speing system subjected to seismic excitation is analyzed by using the fourth-order Runge-Kutta integrated method.
Explicit and implicit solution of the Navier-Stokes equations on a massively parallel computer
NASA Technical Reports Server (NTRS)
Levit, Creon; Jespersen, Dennis
1988-01-01
The design, implementation, and performance of a two-dimensional time-accurate Navier-Stokes solver for the CM2 supercomputer are described. The program uses a single processor for each grid point. Two different time-stepping methods have so far been implemented: an explicit third-order Runge-Kutta method and an implicit approximation-factorization method. The CM2 results are checked against those of a mature well-vectorized Cray 2 program, both for correctness and performance. The code is found to be correct, and the performance in some cases is up to several times that of the Cray 2.
Effect of biquadratic coupling on current induced magnetization switching in Co/Cu/Ni-Fe nanopillar
NASA Astrophysics Data System (ADS)
Aravinthan, D.; Sabareesan, P.; Daniel, M.
2016-05-01
The effect of biquadratic coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the free layer magnetization switching dynamics governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The LLGS equation is numerically solved by using Runge-Kutta fourth order procedure for an applied current density of 5 × 1012 Am-2. Presence of biquadratic coupling in the ferromagnetic layers reduces the magnetization switching time of the nanopillar device from 61 ps to 49 ps.
Finite difference computation of blast diffraction
NASA Astrophysics Data System (ADS)
Hillier, R.; Graham, J. M. R.
1985-07-01
This paper discusses the use of numerical finite difference methods for predicting flow fields in which a shock or blast wave is diffracted at a sharp edge. Three different types of method are studied: Donor Cell differencing with and without Flux Corrected Transport, a Finite Volume method with an explicit artificial viscosity and Runge-Kutta time stepping, and a second order upwind method based on the solution of a Riemann wave problem at cell interfaces. In the case of weak shock waves a comparison is made with the flow field predicted by acoustic theory including flow separation. Results for stronger shocks are also presented.
Simulation of worms transmission in computer network based on SIRS fuzzy epidemic model
NASA Astrophysics Data System (ADS)
Darti, I.; Suryanto, A.; Yustianingsih, M.
2015-03-01
In this paper we study numerically the behavior of worms transmission in a computer network. The model of worms transmission is derived by modifying a SIRS epidemic model. In this case, we consider that the transmission rate, recovery rate and rate of susceptible after recovery follows fuzzy membership functions, rather than constants. To study the transmission of worms in a computer network, we solve the model using the fourth order Runge-Kutta method. Our numerical results show that the fuzzy transmission rate and fuzzy recovery rate may lead to a changing of basic reproduction number which therefore also changes the stability properties of equilibrium points.
NASA Astrophysics Data System (ADS)
Reddy, G. V. R.
2016-08-01
An MHD fluid flow is examined over a vertical plate in the presence of Dufour and Soret effects. The resulting momentum, energy and concentration equations are then made similar by introducing the usual similarity transformations. These similar equations are then solved numerically using the Runge-Kutta fourth order method with shooting technique. The effects of various parameters on the dimensionless velocity, temperature and concentration profiles as well as the local values of the skin-friction coefficient, the Nusselt number and Sherwood number are displayed graphically and in a tabular form. A comparison with previously published work is obtained and an excellent agreement is found.
Global bifurcations of a taut string with 1:2 internal resonance
NASA Astrophysics Data System (ADS)
Zhang, Xiaohua; Chen, Fangqi; Jing, Taiyan
2014-04-01
The global bifurcations of a taut string are investigated with the case of 1:2 internal resonance. The method of multiple scales is applied to obtain a system of autonomous ordinary differential equations. Based on the normal form theory, the desired form for the global perturbation method is obtained. Then the method developed by Kovacic and Wiggins is used to find explicit sufficient conditions for chaos to occur by identifying the existence of a Silnikov-type homoclinic orbit. Finally, numerical results obtained by using fourth-order Runge-Kutta method agree with the theoretical analysis at least qualitatively.
Modeling of heat transfer in a rotary kiln thermal desorder for removal of petroleum from soils
Chern, Hsien-Tsung; Krasnoperov, L.V.; Bozzelli, J.W.
1996-10-01
A continuous feed rotary kiln thermal desorber was designed and constructed to study the heat transfer in removal of petroleum hydrocarbons from contaminated soils. A mathematical model of heat transfer that correlates temperatures of gas, soil, and kiln wall will purge gas flow, soil feed rate, kiln rotation speed and soil residence time in the kiln desorber is developed. A fourth order Runge-Kutta method was used to numerically integrate the heat transfer process along the kiln length and to calculate the temperature profiles. Comparison of predicted and measured gas and soil temperature profile is presented.
A hybrid Pseudo-spectral Immersed-Boundary Method for Applications to Aquatic Locomotion
NASA Astrophysics Data System (ADS)
Ren, Zheng; Hall, David; Mohseni, Kamran
2011-11-01
A hybrid pseudo-spectral immersed boundary method is developed for application in marine locomotion. Spatial derivatives are calculated using pseudo-spectral method while a 2nd-order Runge-Kutta scheme is used for time integration. The singular force applied on the immersed boundary is obtained using a direct forcing method. To avoid Gibb's phenomenon in the spectral method, we regularize the force by smoothing it over several grid cells. This method has the advantage of spectral accuracy and the flexibility to model irregular, moving boundaries on a Cartesian coordinate without complex mesh generation. The method is applied to examine locomotion of jellyfish for both jetting and paddling jellyfish.
H. Qin and X. Guan
2008-02-11
A variational symplectic integrator for the guiding-center motion of charged particles in general magnetic fields is developed for long-time simulation studies of magnetized plasmas. Instead of discretizing the differential equations of the guiding-center motion, the action of the guiding-center motion is discretized and minimized to obtain the iteration rules for advancing the dynamics. The variational symplectic integrator conserves exactly a discrete Lagrangian symplectic structure, and has better numerical properties over long integration time, compared with standard integrators, such as the standard and variable time-step fourth order Runge-Kutta methods.
An ILLIAC program for the numerical simulation of homogeneous incompressible turbulence
NASA Technical Reports Server (NTRS)
Rogallo, R. S.
1977-01-01
An algorithm and ILLIAC computer program, developed for the simulation of homogeneous incompressible turbulence in the presence of an applied mean strain, are described. The turbulence field is represented spatially by a truncated triple Fourier series (spectral method) and followed in time using a fourth-order Runge-Kutta algorithm. These include: (1) transformation of variables suggested by Taylor's sudden-distortion theory; (2) implicit viscous diffusion by use of an integrating factor; (3) implicit pressure calculation suggested by Taylor's sudden-distortion theory, and (4) inexpensive control of aliasing by random and phased coordinate shifts.
Sub-diffusive electronic transport in a DNA single-strand chain with electron-phonon coupling
NASA Astrophysics Data System (ADS)
Sales, M. O.; Lyra, M. L.; de Moura, F. A. B. F.; Fulco, U. L.; Albuquerque, E. L.
2015-01-01
We investigate the electronic wavepacket dynamics in a finite segment of a DNA single-strand chain considering the electron-phonon coupling. Our theoretical approach makes use of an effective tight-binding Hamiltonian to describe the electron dynamics, together with a classical harmonic Hamiltonian to treat the intrinsic DNA vibrations. An effective time-dependent Schrödinger equation is then settled up and solved numerically for an initially localized wave-packet using the standard Dormand-Prince eighth-order Runge-Kutta method. Our numerical results indicate the presence of a sub-diffusive electronic wavepacket spread mediated by the electron-phonon interaction.
NASA Astrophysics Data System (ADS)
Kalteh, M.; Ghorbani, S.; Khademinejad, T.
2016-05-01
An axisymmetric magnetohydrodynamic (MHD) boundary layer flow and heat transfer of a fluid over a slender cylinder are investigated numerically. The effects of viscous dissipation, thermal radiation, and surface transverse curvature are taken into account in the simulations. For this purpose, the governing partial differential equations are transformed to ordinary differential equations by using appropriate similarity transformations. The resultant ordinary differential equations along with appropriate boundary conditions are solved by the fourth-order Runge-Kutta method combined with the shooting technique. The effects of various parameters on the velocity and temperature profiles, local skin friction coefficient, and Nusselt number are analyzed.
Isa, Sharena Mohamad; Ali, Anati
2015-10-22
In this paper, the hydromagnetic flow of dusty fluid over a vertical stretching sheet with thermal radiation is investigated. The governing partial differential equations are reduced to nonlinear ordinary differential equations using similarity transformation. These nonlinear ordinary differential equations are solved numerically using Runge-Kutta Fehlberg fourth-fifth order method (RKF45 Method). The behavior of velocity and temperature profiles of hydromagnetic fluid flow of dusty fluid is analyzed and discussed for different parameters of interest such as unsteady parameter, fluid-particle interaction parameter, the magnetic parameter, radiation parameter and Prandtl number on the flow.
Numerical modeling of the transmission dynamics of drug-sensitive and drug-resistant HSV-2
NASA Astrophysics Data System (ADS)
Gumel, A. B.
2001-03-01
A competitive finite-difference method will be constructed and used to solve a modified deterministic model for the spread of herpes simplex virus type-2 (HSV-2) within a given population. The model monitors the transmission dynamics and control of drug-sensitive and drug-resistant HSV-2. Unlike the fourth-order Runge-Kutta method (RK4), which fails when the discretization parameters exceed certain values, the novel numerical method to be developed in this paper gives convergent results for all parameter values.
Yang, Wancai; Guan, Lingjie
2012-07-01
A global collaborative effort is pivotal to conquer cancer. Themed "Emerging role of China in global clinical development of novel anti-cancer drugs", the US Chinese Anti-Cancer Association (USCACA) held its 4th annual meeting in Chicago on June 2, 2012, in conjunction with the American Society of Clinical Oncology (ASCO) annual meeting to further bridge the US and China together to outsmart cancer. Although a young organization, USCACA has made significant contributions to this goal in the 3 years since its inception through extensive collaboration with academic organizations, the pharmaceutical industry, and governmental agencies. USCACA has engaged various stakeholders in developing translational and personalized medical strategies to facilitate new anti-cancer drug development and clinical trials in China. USCACA has initiated and implemented the USCACA-National Foundation for Cancer Research (NFCR) scholarship to encourage overseas returnees to continue cancer research in China. USCACA announced the Hengrui-USCACA scholarship to fund clinical trial staff from China to conduct the observation of early oncologic clinical trials in the US. During the annual meeting, distinguished panelists and the audience discussed the following critical topics:(1) oncologic translational research and early development capabilities in China;(2) novel chemical entity development and partnership with Chinese companies; and (3) Chinese participation in global anti-cancer drug development. USCACA will continue to promote collaborations among cancer researchers and clinicians in the US and China by engaging in more frequent communications and joint efforts across fields, disciplines, and countries, diligently working together toward curing and eliminating cancers. PMID:22739264
Hoelscher, Deanna M; Kelder, Steven H; Pérez, Adriana; Day, R Sue; Benoit, Julia S; Frankowski, Ralph F; Walker, Joey L; Lee, Eun S
2010-07-01
Although national and state estimates of child obesity are available, data at these levels are insufficient to monitor effects of local obesity prevention initiatives. The purpose of this study was to examine regional changes in the prevalence of obesity due to statewide policies and programs among children in grades 4, 8, and 11 in Texas Health Services Regions (HSRs) between 2000-2002 and 2004-2005, and nine selected counties in 2004-2005. A cross-sectional, probability-based sample of 23,190 Texas students in grades 4, 8, and 11 were weighed and measured to obtain BMI. Obesity was >95th percentile for BMI by age/sex using Centers for Disease Control and Prevention growth charts. Child obesity prevalence significantly decreased between 2000-2002 and 2004-2005 for 4th grade students in the El Paso HSR (-7.0%, P = 0.005). A leveling off in the prevalence of obesity was noted for all other regions for grades 4, 8, and 11. County-level data supported the statistically significant decreases noted in the El Paso region. The reduction of child obesity levels observed in the El Paso area is one of the few examples of effective programs and policies based on a population-wide survey: in this region, a local foundation funded extensive regional implementation of community programs for obesity prevention, including an evidence-based elementary school-based health promotion program, adult nutrition and physical activity programs, and a radio and television advertising campaign. Results emphasize the need for sustained school, community, and policy efforts, and that these efforts can result in decreases in child obesity at the population level. PMID:19798066
ERIC Educational Resources Information Center
Smith, Darcie D.
2012-01-01
Eighty-seven 4th, 5th and 6th grade students were administered the "Derivational Relatedness Interview" (DRI) (Templeton, Smith, Moloney, Van Pelt, & Ives, 2009). The purpose of this instrument is to explore students' understanding of derivational morphology. During the same week, the subjects were also administered an Upper…
Poland, Gregory A; Fleming, Douglas M; Treanor, John J; Maraskovsky, Eugene; Luke, Thomas C; Ball, Emma M A; Poland, Caroline M
2013-04-17
Both seasonal and pandemic influenza cause considerable morbidity and mortality globally. In addition, the ongoing threat of new, unpredictable influenza pandemics from emerging variant strains cannot be underestimated. Recently bioCSL (previously known as CSL Biotherapies) sponsored a symposium 'New Wisdom to Defy an Old Enemy' at the 4th Influenza Vaccines for the World Congress in Valencia, Spain. This symposium brought together a renowned faculty of experts to discuss lessons from past experience, novel influenza vaccine developments, and new methods to increase vaccine acceptance and coverage. Specific topics reviewed and discussed included new vaccine development efforts focused on improving efficacy via alternative administration routes, dose modifications, improved adjuvants, and the use of master donor viruses. Improved safety was also discussed, particularly the new finding of an excess of febrile reactions isolated to children who received the 2010 Southern Hemisphere (SH) trivalent inactivated influenza vaccine (TIV). Significant work has been done to both identify the cause and minimize the risk of febrile reactions in children. Other novel prophylactic and therapeutic advances were discussed including immunotherapy. Standard IVIg and hIVIg have been used in ferret studies and human case reports with promising results. New adjuvants, such as ISCOMATRIX™ adjuvant, were noted to provide single-dose, prolonged protection with seasonal vaccine after lethal H5N1 virus challenge in a ferret model of human influenza disease. The data suggest that adjuvanted seasonal influenza vaccines may provide broader protection than unadjuvanted vaccines. The use of an antigen-formulated vaccine to induce broad protection between pandemics that could bridge the gap between pandemic declaration and the production of a homologous vaccine was also discussed. Finally, despite the availability of effective vaccines, most current efforts to increase influenza vaccine coverage
NASA Astrophysics Data System (ADS)
Rennie, Adrian R.
2008-03-01
Neutron scattering is used as a tool to study problems in disciplines that include chemistry, materials science, biology and condensed matter physics as well as problems from neighbouring disciplines such as geology, environmental sciences and archaeology. Equipment for these studies is found at laboratories with research reactors or spallation neutron sources and there are many recent or current developments with new instruments and even entirely new facilities such as the Spallation Neutron Source at Oak Ridge, USA, the OPAL reactor at Lucas Heights, Australia and the second target station at the ISIS facility in the UK. Design and optimization of the instruments at these facilities involves work with many research laboratories and groups in universities. Every four years the European Conference on Neutron Scattering (ECNS) brings together both the specialists in neutron instrumentation and the community of users (in intervening years there are International and American conferences). In June 2007 about 700 delegates came to the 4th ECNS that was held in Lund, Sweden. There were more than 600 presentations as talks and posters. The opportunity to publish papers in Measurement Science and Technology that relate to neutron scattering instrumentation and method development was offered to the participants, and the papers that follow describe some of the recent activity in this field. Accounts of work on condensed matter science and the applications of neutron scattering appear separately in Journal of Physics: Condensed Matter. There are, of course, many features of neutron instrumentation that are specific to this particular field of measurement. However, there are also many elements of apparatus and experiment design that can usefully be shared with a broader community. It is hoped that this issue with papers from ECNS will find a broad community of interest. Apart from descriptions of overall design of diffractometers and spectrometers there are accounts of new
Poland, Gregory A; Fleming, Douglas M; Treanor, John J; Maraskovsky, Eugene; Luke, Thomas C; Ball, Emma M A; Poland, Caroline M
2013-04-17
Both seasonal and pandemic influenza cause considerable morbidity and mortality globally. In addition, the ongoing threat of new, unpredictable influenza pandemics from emerging variant strains cannot be underestimated. Recently bioCSL (previously known as CSL Biotherapies) sponsored a symposium 'New Wisdom to Defy an Old Enemy' at the 4th Influenza Vaccines for the World Congress in Valencia, Spain. This symposium brought together a renowned faculty of experts to discuss lessons from past experience, novel influenza vaccine developments, and new methods to increase vaccine acceptance and coverage. Specific topics reviewed and discussed included new vaccine development efforts focused on improving efficacy via alternative administration routes, dose modifications, improved adjuvants, and the use of master donor viruses. Improved safety was also discussed, particularly the new finding of an excess of febrile reactions isolated to children who received the 2010 Southern Hemisphere (SH) trivalent inactivated influenza vaccine (TIV). Significant work has been done to both identify the cause and minimize the risk of febrile reactions in children. Other novel prophylactic and therapeutic advances were discussed including immunotherapy. Standard IVIg and hIVIg have been used in ferret studies and human case reports with promising results. New adjuvants, such as ISCOMATRIX™ adjuvant, were noted to provide single-dose, prolonged protection with seasonal vaccine after lethal H5N1 virus challenge in a ferret model of human influenza disease. The data suggest that adjuvanted seasonal influenza vaccines may provide broader protection than unadjuvanted vaccines. The use of an antigen-formulated vaccine to induce broad protection between pandemics that could bridge the gap between pandemic declaration and the production of a homologous vaccine was also discussed. Finally, despite the availability of effective vaccines, most current efforts to increase influenza vaccine coverage
NASA Astrophysics Data System (ADS)
Lathuilière, Cyril; Baraille, Rémy; Le Boyer, Arnaud
2015-04-01
The French navy hydrographic service uses a modified version of the Hybrid coordinate ocean model (HYCOM) for operational oceanographic applications. In the framework of the COMODO project, a series of test cases has been carried out to measure the numerical efficiency of the model. It addresses a wide panel of oceanic processes (baroclinic eddy, baroclinic jet, coastal upwelling, internal tides) and is useful to examine most of numerical schemes (advection schemes, time stepping, pressure gradient, …). The objectives of this study are first to assess the numerical performance of the present model to guide the modelers to make the suitable choices, and second to examine how the performances may be improved in the next years. We examine the sensitivity of the main choices for Hycom (2th or 4th order advection schemes, and viscosity values) in baroclinic eddy and baroclinic jet test cases. Both test cases are run using increasing resolution. The highest resolution provides a reference for studying the coarser resolutions. In the baroclinic vortex test case, the second order vector form scheme is well performing whereas the 4th order scheme appears to be more accurate in the baroclinic jet test case. This is probably due to the lack of fine scale energy in the baroclinic vortex test case allowing simulations with very tiny dissipation rates. We focus then on the sensitivity of the performance to vertical coordinate choices. The ability of Hycom to switch between isopycnal coordinate and quasi geopotential coordinate provides useful insights for example on the sensitivity of numerical diapycnal mixing to remapping scheme. This is particularly visible on the internal tide test case. The type of vertical coordinate is also important for potential vorticity structures. The shape of the baroclinic vortex is found to be different in geopotential and isopycnal coordinates. At coarse resolution, the potential vorticity structures seem to be better resolved in isopycnal
A High-Resolution Capability for Large-Eddy Simulation of Jet Flows
NASA Technical Reports Server (NTRS)
DeBonis, James R.
2011-01-01
A large-eddy simulation (LES) code that utilizes high-resolution numerical schemes is described and applied to a compressible jet flow. The code is written in a general manner such that the accuracy/resolution of the simulation can be selected by the user. Time discretization is performed using a family of low-dispersion Runge-Kutta schemes, selectable from first- to fourth-order. Spatial discretization is performed using central differencing schemes. Both standard schemes, second- to twelfth-order (3 to 13 point stencils) and Dispersion Relation Preserving schemes from 7 to 13 point stencils are available. The code is written in Fortran 90 and uses hybrid MPI/OpenMP parallelization. The code is applied to the simulation of a Mach 0.9 jet flow. Four-stage third-order Runge-Kutta time stepping and the 13 point DRP spatial discretization scheme of Bogey and Bailly are used. The high resolution numerics used allows for the use of relatively sparse grids. Three levels of grid resolution are examined, 3.5, 6.5, and 9.2 million points. Mean flow, first-order turbulent statistics and turbulent spectra are reported. Good agreement with experimental data for mean flow and first-order turbulent statistics is shown.
A hybrid symplectic PIC/spectral scheme for one-dimensional electrostatic simulations
Doxas, I.; Cary, J.R.
1996-12-31
We develop a hybrid PIC/spectral integration scheme based on the explicit symplectic integrator of reference. We find that for low-accuracy short-term integration (5% accuracy over {omega}{sub p}t = 500) the second-order symplectic method is most efficient, outperforming the fourth-order method by 65% and non-symplectic methods such as Runge-Kutta, Bulirsch-Stoer and {open_quote}naive{close_quote} leap-frog by a factor of 3-10. For high-accuracy short-term integration (10{sup -4} over w{sub p}t = 500) the second-order symplectic method is 20% more efficient than both the fourth-order method and Bulirsch-Stoer, and a factor of 8-20 more efficient than Runge-Kutta and {open_quote}naive{close_quote} leap-frog. For long-term integration (w{sub p}t = 10{sup 5}) the second order symplectic method outperforms all non-symplectic methods by a factor of 8-20. We also show that the symplectic method is more robust to roundoff error than all other methods we tested, and that for simulations with a small number of particles per wavelength (usuall in plasma simulations) cubic spline interpolation is more efficient that linear interpolation.
Lorber, A.A.; Carey, G.F.; Bova, S.W.; Harle, C.H.
1996-12-31
The connection between the solution of linear systems of equations by iterative methods and explicit time stepping techniques is used to accelerate to steady state the solution of ODE systems arising from discretized PDEs which may involve either physical or artificial transient terms. Specifically, a class of Runge-Kutta (RK) time integration schemes with extended stability domains has been used to develop recursion formulas which lead to accelerated iterative performance. The coefficients for the RK schemes are chosen based on the theory of Chebyshev iteration polynomials in conjunction with a local linear stability analysis. We refer to these schemes as Chebyshev Parameterized Runge Kutta (CPRK) methods. CPRK methods of one to four stages are derived as functions of the parameters which describe an ellipse {Epsilon} which the stability domain of the methods is known to contain. Of particular interest are two-stage, first-order CPRK and four-stage, first-order methods. It is found that the former method can be identified with any two-stage RK method through the correct choice of parameters. The latter method is found to have a wide range of stability domains, with a maximum extension of 32 along the real axis. Recursion performance results are presented below for a model linear convection-diffusion problem as well as non-linear fluid flow problems discretized by both finite-difference and finite-element methods.
MIST: a user-friendly metabolic simulator.
Ehlde, M; Zacchi, G
1995-04-01
The Metabolic Interactive Simulation Tool, MIST, is a software package, running under Microsoft Windows 3.1, which can be used for dynamic simulations, stoichiometric calculations and control analysis of metabolic pathways. The pathways can be of any complexity and are defined by the user in a simple, interactive way. The user-defined enzymatic rate equations can be compiled either by an external or an internal compiler. Simulations of pathways compiled by an external compiler run significantly faster, but since these compilers are commercial software, they are not distributed together with MIST. The simulations are performed by numerical integration of a set of ordinary differential equations. The integration can be done by either an explicit fourth-order Runge-Kutta algorithm or a semi-implicit third-order Runge-Kutta algorithm, both with adjustable step size. The second algorithm can be used if the set of differential equations is stiff. Vector-based drawing facilities are included in the program, with which results can be presented in graphs. Results of simulations, including graphics, can be stored in files. MIST is a very user-friendly, flexible and yet powerful program, with the mathematical details regarding models, simulations and calculations hidden from the user. This makes it suitable for scientists and students with limited computer experience. PMID:7620994
Acceleration on stretched meshes with line-implicit LU-SGS in parallel implementation
NASA Astrophysics Data System (ADS)
Otero, Evelyn; Eliasson, Peter
2015-02-01
The implicit lower-upper symmetric Gauss-Seidel (LU-SGS) solver is combined with the line-implicit technique to improve convergence on the very anisotropic grids necessary for resolving the boundary layers. The computational fluid dynamics code used is Edge, a Navier-Stokes flow solver for unstructured grids based on a dual grid and edge-based formulation. Multigrid acceleration is applied with the intention to accelerate the convergence to steady state. LU-SGS works in parallel and gives better linear scaling with respect to the number of processors, than the explicit scheme. The ordering techniques investigated have shown that node numbering does influence the convergence and that the orderings from Delaunay and advancing front generation were among the best tested. 2D Reynolds-averaged Navier-Stokes computations have clearly shown the strong efficiency of our novel approach line-implicit LU-SGS which is four times faster than implicit LU-SGS and line-implicit Runge-Kutta. Implicit LU-SGS for Euler and line-implicit LU-SGS for Reynolds-averaged Navier-Stokes are at least twice faster than explicit and line-implicit Runge-Kutta, respectively, for 2D and 3D cases. For 3D Reynolds-averaged Navier-Stokes, multigrid did not accelerate the convergence and therefore may not be needed.
Central difference TVD and TVB schemes for time dependent and steady state problems
NASA Technical Reports Server (NTRS)
Jorgenson, P.; Turkel, E.
1992-01-01
We use central differences to solve the time dependent Euler equations. The schemes are all advanced using a Runge-Kutta formula in time. Near shocks, a second difference is added as an artificial viscosity. This reduces the scheme to a first order upwind scheme at shocks. The switch that is used guarantees that the scheme is locally total variation diminishing (TVD). For steady state problems it is usually advantageous to relax this condition. Then small oscillations do not activate the switches and the convergence to a steady state is improved. To sharpen the shocks, different coefficients are needed for different equations and so a matrix valued dissipation is introduced and compared with the scalar viscosity. The connection between this artificial viscosity and flux limiters is shown. Any flux limiter can be used as the basis of a shock detector for an artificial viscosity. We compare the use of the van Leer, van Albada, mimmod, superbee, and the 'average' flux limiters for this central difference scheme. For time dependent problems, we need to use a small enough time step so that the CFL was less than one even though the scheme was linearly stable for larger time steps. Using a total variation bounded (TVB) Runge-Kutta scheme yields minor improvements in the accuracy.
A Parallel Compact Multi-Dimensional Numerical Algorithm with Aeroacoustics Applications
NASA Technical Reports Server (NTRS)
Povitsky, Alex; Morris, Philip J.
1999-01-01
In this study we propose a novel method to parallelize high-order compact numerical algorithms for the solution of three-dimensional PDEs (Partial Differential Equations) in a space-time domain. For this numerical integration most of the computer time is spent in computation of spatial derivatives at each stage of the Runge-Kutta temporal update. The most efficient direct method to compute spatial derivatives on a serial computer is a version of Gaussian elimination for narrow linear banded systems known as the Thomas algorithm. In a straightforward pipelined implementation of the Thomas algorithm processors are idle due to the forward and backward recurrences of the Thomas algorithm. To utilize processors during this time, we propose to use them for either non-local data independent computations, solving lines in the next spatial direction, or local data-dependent computations by the Runge-Kutta method. To achieve this goal, control of processor communication and computations by a static schedule is adopted. Thus, our parallel code is driven by a communication and computation schedule instead of the usual "creative, programming" approach. The obtained parallelization speed-up of the novel algorithm is about twice as much as that for the standard pipelined algorithm and close to that for the explicit DRP algorithm.
NASA Astrophysics Data System (ADS)
Cavaglieri, Daniele; Bewley, Thomas; Mashayek, Ali
2015-11-01
We present a new code, Diablo 2.0, for the simulation of the incompressible NSE in channel and duct flows with strong grid stretching near walls. The code leverages the fractional step approach with a few twists. New low-storage IMEX (implicit-explicit) Runge-Kutta time-marching schemes are tested which are superior to the traditional and widely-used CN/RKW3 (Crank-Nicolson/Runge-Kutta-Wray) approach; the new schemes tested are L-stable in their implicit component, and offer improved overall order of accuracy and stability with, remarkably, similar computational cost and storage requirements. For duct flow simulations, our new code also introduces a new smoother for the multigrid solver for the pressure Poisson equation. The classic approach, involving alternating-direction zebra relaxation, is replaced by a new scheme, dubbed tweed relaxation, which achieves the same convergence rate with roughly half the computational cost. The code is then tested on the simulation of a shear flow instability in a duct, a classic problem in fluid mechanics which has been the object of extensive numerical modelling for its role as a canonical pathway to energetic turbulence in several fields of science and engineering.
Numerical integration of orbits of planetary satellites.
NASA Astrophysics Data System (ADS)
Hadjifotinou, K. G.; Harper, D.
1995-11-01
The 10th-order Gauss-Jackson backward difference numerical integration method and the Runge-Kutta-Nystroem RKN12(10)17M method were applied to the equations of motion and variational equations of the Saturnian satellite system. We investigated the effect of step-size on the stability of the Gauss-Jackson method in the two distinct cases arising from the inclusion or exclusion of the corrector cycle in the integration of the variational equations. In the predictor-only case, we found that instability occurred when the step-size was greater than approximately 1/76 of the orbital period of the innermost satellite. In the predictor-corrector case, no such instability was observed, but larger step-sizes yield significant loss in accuracy. By contrast, the investigation of the Runge-Kutta-Nystroem method showed that it allows the use of much larger step-sizes and can still obtain high-accuracy results, thus making evident the superiority of the method for the integration of planetary satellite systems.
Error Patterns in Ordering Fractions among At-Risk Fourth-Grade Students
ERIC Educational Resources Information Center
Malone, Amelia Schneider; Fuchs, Lynn S.
2015-01-01
The 3 purposes of this study were to: (a) describe fraction ordering errors among at-risk 4th-grade students; (b) assess the effect of part-whole understanding and accuracy of fraction magnitude estimation on the probability of committing errors; and (c) examine the effect of students' ability to explain comparing problems on the probability of…
ERIC Educational Resources Information Center
Urbaczewski, Andrew; Urbaczewski, Lise
The objective of this study was to find the answers to two primary research questions: "Do students learn programming languages better when they are offered in a particular order, such as 4th generation languages before 3rd generation languages?"; and "Do students learn programming languages better when they are taken in separate semesters as…
ERIC Educational Resources Information Center
Gibeault, Michael
2005-01-01
Change orders. The words can turn the stomachs of administrators. Horror stories about change orders create fear and distrust among school officials, designers and builders. Can change orders be avoided? If car manufacturers can produce millions of intricately designed vehicles, why can't the same quality control be achieved on a construction…
The Three-Dimensional Finite-Volume Non-Hydrostatic Icosahedral Model (NIM)
NASA Astrophysics Data System (ADS)
Lee, J. L.; MacDonald, A. E.
2014-12-01
A multi-scales Non-hydrostatic Icosahedral Model (NIM) has been developed at Earth System Research Laboratory (ESRL) to meet NOAA's future prediction mission ranging from mesoscale short-range, high-impact weather forecasts to longer-term intra-seasonal climate prediction. NIM formulates the latest numerical innovation of the three-dimensional finite-volume control volume on the quasi-uniform icosahedral grid suitable for ultra-high resolution simulations. NIM is designed to utilize the state-of-art computing architecture such as Graphic Processing Units (GPU) processors to run globally at kilometer scale resolution to explicitly resolve convective storms and complex terrains. The novel features of NIM numerical design include: 1.1. A local coordinate system upon which finite-volume integrations are undertaken. The use of a local Cartesian coordinate greatly simplifies the mathematic formulation of the finite-volume operators and leads to the finite-volume integration along straight lines on the plane, rather than along curved lines on the spherical surface. 1.2. A general indirect addressing scheme developed for modeling on irregular grid. It arranges the icosahedral grid with a one-dimensional vector loop structure, table specified memory order, and an indirect addressing scheme that yields very compact code despite the complexities of this grid. 1.3. Use of three-dimensional finite-volume integration over control volumes constructed on the height coordinates. Three-dimensional finite-volume integration accurately represents the Newton Third Law over terrain and improves pressure gradient force over complex terrain. 1.4. Use of the Runge-Kutta 4th order conservative and positive-definite transport scheme 1.5. NIM dynamical solver has been implemented on CPU as well as GPU. As one of the potential candidates for NWS next generation models, NIM dynamical core has been successfully verified with various benchmark test cases including those proposed by DCMIP
NASA Technical Reports Server (NTRS)
Hiltner, Dale W.
2000-01-01
The TAILSIM program uses a 4th order Runge-Kutta method to integrate the standard aircraft equations-of-motion (EOM). The EOM determine three translational and three rotational accelerations about the aircraft's body axis reference system. The forces and moments that drive the EOM are determined from aerodynamic coefficients, dynamic derivatives, and control inputs. Values for these terms are determined from linear interpolation of tables that are a function of parameters such as angle-of-attack and surface deflections. Buildup equations combine these terms and dimensionalize them to generate the driving total forces and moments. Features that make TAILSIM applicable to studies of tailplane stall include modeling of the reversible control System, modeling of the pilot performing a load factor and/or airspeed command task, and modeling of vertical gusts. The reversible control system dynamics can be described as two hinged masses connected by a spring. resulting in a fifth order system. The pilot model is a standard form of lead-lag with a time delay applied to an integrated pitch rate and/or airspeed error feedback. The time delay is implemented by a Pade approximation, while the commanded pitch rate is determined by a commanded load factor. Vertical gust inputs include a single 1-cosine gust and a continuous NASA Dryden gust model. These dynamic models. coupled with the use of a nonlinear database, allow the tailplane stall characteristics, elevator response, and resulting aircraft response, to be modeled. A useful output capability of the TAILSIM program is the ability to display multiple post-run plot pages to allow a quick assessment of the time history response. There are 16 plot pages currently available to the user. Each plot page displays 9 parameters. Each parameter can also be displayed individually. on a one plot-per-page format. For a more refined display of the results the program can also create files of tabulated data. which can then be used by other
NASA Astrophysics Data System (ADS)
Guo-Dong, Shi; Yong, Huang; Ke-Yong, Zhu
2016-06-01
A Runge-Kutta ray-tracing method for determining the thermal emissions of a two-dimensional semitransparent graded-index medium has been developed for this study. A backward ray-tracing method and a backward Monte Carlo method were employed in the calculations. The emission characteristics of a linear refractive index medium were investigated. The results of the Runge-Kutta ray-tracing method were shown to agree well with previously obtained exact solutions. The apparent emissivities of a radial refractive index medium obtained using the Runge-Kutta ray-tracing method fit the analytical solutions well. However, for a sinusoidally distributed nonlinear refractive index medium, the Runge-Kutta ray-tracing method revised emissivity results differed from the results of a linear refractive index bar model at certain angles. The results show that the Runge-Kutta ray-tracing method is effective in dealing with the radiative transfer problems of multidimensional graded index media.
NASA Astrophysics Data System (ADS)
Bartholomay, Sirko; Ramos-García, Néstor; Mikkelsen, Robert Flemming; Technical University of Denmark (DTU)-WInd Energy Team
2014-11-01
The viscous-inviscid flow solver Q3UIC for 2D aerodynamics has recently been developed at the Technical University of Denmark. The Q3UIC solver takes viscous and unsteady effects into account by coupling an unsteady inviscid panel method with the integral boundary layer equations by means of a strong coupling between the viscous and inviscid parts, and in this respect differs from other classic panel codes e.g. Xfoil. In the current work a Runge-Kutta-Nyström scheme was employed to couple inertial, elastic and aerodynamical forces and moments calculated by Q3UIC for a two-dimensional blade section in the time-domain. Numerical simulations are validated by a three step experimental verification process carried out in the low-turbulence wind tunnel at DTU. First, a comparison against steady experiments for a NACA 64418 profile and a flexible trailing edge flap is presented for different fixed flap angles, and second, the measured aerodynamic characteristics considering prescribed motion of the airfoil with a moving flap are compared to the Q3UIC predictions. Finally, an aeroelastic experiment for one degree of freedom-airfoil pitching- is used to evaluate the accuracy of aeroelastic coupling.
Access of energetic particles to Titan's exobase: A study of Cassini's T9 flyby
NASA Astrophysics Data System (ADS)
Regoli, L. H.; Roussos, E.; Feyerabend, M.; Jones, G. H.; Krupp, N.; Coates, A. J.; Simon, S.; Motschmann, U.; Dougherty, M. K.
2016-10-01
We study how the local electromagnetic disturbances introduced by Titan affect the ionization rates of the atmosphere. For this, we model the precipitation of energetic particles, specifically hydrogen and oxygen ions with energies between 1 keV and 1 MeV, into Titan's exobase for the specific magnetospheric configuration of the T9 flyby. For the study, a particle tracing software package is used which consists of an integration of the single particle Lorentz force equation using a 4th order Runge-Kutta numerical method. For the electromagnetic disturbances, the output of the A.I.K.E.F. hybrid code (kinetic ions, fluid electrons) is used, allowing the possibility of analyzing the disturbances and asymmetries in the access of energetic particles originated by their large gyroradii. By combining these methods, 2D maps showing the access of each set of particles were produced. We show that the access of different particles is largely dominated by their gyroradii, with the complexity of the maps increasing with decreasing gyroradius, due to the larger effect that local disturbances introduced by the presence of the moon have in the trajectory of the particles with lower energies. We also show that for particles with gyroradii much larger than the moon's radius, simpler descriptions of the electromagnetic environment can reproduce similar results to those obtained when using the full hybrid simulation description, with simple north-south fields being sufficient to reproduce the hybrid code results for O+ ions with energies larger than 10 keV but not enough to reproduce those for H+ ions at any of the energies covered in the present study. Finally, by combining the maps created with upstream plasma flow measurements by the MIMI/CHEMS instrument, we are able to estimate normalized fluxes arriving at different selected positions of the moon's exobase. We then use these fluxes to calculate energy deposition and non-dissociative N2 ionization rates for precipitating O+ and H
Kabaliuk, N; Jermy, M C; Williams, E; Laber, T L; Taylor, M C
2014-12-01
Bloodstain Pattern Analysis (BPA) provides information about events during an assault, e.g. location of participants, weapon type and number of blows. To extract the maximum information from spatter stains, the size, velocity and direction of the drop that produces each stain, and forces acting during flight, must be known. A numerical scheme for accurate modeling of blood drop flight, in typical crime scene conditions, including droplet oscillation, deformation and in-flight disintegration, was developed and validated against analytical and experimental data including passive blood drop oscillations, deformation at terminal velocity, cast-off and impact drop deformation and breakup features. 4th order Runge-Kutta timestepping was used with the Taylor Analogy Breakup (TAB) model and Pilch and Erdman's (1987) expression for breakup time. Experimental data for terminal velocities, oscillations, and deformation was obtained via digital high-speed imaging. A single model was found to describe drop behavior accurately in passive, cast off and impact scenarios. Terminal velocities of typical passive drops falling up to 8m, distances and times required to reach them were predicted within 5%. Initial oscillations of passive blood drops with diameters of 1mm
Sound Radiation from Ducted Fans Using Computational Aeroacoustics on Parallel Computers.
NASA Astrophysics Data System (ADS)
Ozyoruk, Yusuf
1995-01-01
As a component of a more advanced, new generation fan noise prediction technology, a computational aeroacoustics algorithm has been developed using an entirely new approach. Unlike previous approaches, the current method accounts for the nonuniform background flow and aerodynamic-acoustic coupling issues by solving the 3-D, time-dependent, full nonlinear Euler equations (although the developed computer program is a Navier-Stokes solver). The equations are solved on a 3-D body fitted curvilinear coordinate system using temporally and spatially 4th-order accurate finite difference, Runge -Kutta time integration. The time-accurate flow field is determined only in a relatively small physical domain using nonreflecting boundary conditions on its outer boundaries. A moving surface Kirchhoff method using the formulation of Farassat and Myers has been developed and coupled to the flow solver for far-field noise predictions. The acoustic field is obtained by subtracting the mean field from the total field. To establish the mean flow field, steady state solutions are required and Jameson's full approximation storage multigrid method has been extended to make use of the current high resolution algorithm for obtaining such solutions fast. Formulations in cylindrical coordinates together with cell-centered finite differencing are used to effectively treat the grid singularity along the centerline. Well designed grids aid this treatment. A 3-D grid generator has been developed using the conformal mappings of Ives and Menor to provide the hybrid radiation code with capabilities for very rapid and good quality mesh generation. The hybrid radiation code has been written in CM-Fortran, which is essentially High Performance Fortran. Some novel optimization procedures have been developed and implemented in the code, which runs efficiently on the CM-200 and CM-5 parallel computers. The code has been tested solving a large variety of problems, ranging from an oscillating piston problem
Kabaliuk, N; Jermy, M C; Williams, E; Laber, T L; Taylor, M C
2014-12-01
Bloodstain Pattern Analysis (BPA) provides information about events during an assault, e.g. location of participants, weapon type and number of blows. To extract the maximum information from spatter stains, the size, velocity and direction of the drop that produces each stain, and forces acting during flight, must be known. A numerical scheme for accurate modeling of blood drop flight, in typical crime scene conditions, including droplet oscillation, deformation and in-flight disintegration, was developed and validated against analytical and experimental data including passive blood drop oscillations, deformation at terminal velocity, cast-off and impact drop deformation and breakup features. 4th order Runge-Kutta timestepping was used with the Taylor Analogy Breakup (TAB) model and Pilch and Erdman's (1987) expression for breakup time. Experimental data for terminal velocities, oscillations, and deformation was obtained via digital high-speed imaging. A single model was found to describe drop behavior accurately in passive, cast off and impact scenarios. Terminal velocities of typical passive drops falling up to 8m, distances and times required to reach them were predicted within 5%. Initial oscillations of passive blood drops with diameters of 1mm
NASA Astrophysics Data System (ADS)
Couston, L.; Mei, C.; Alam, M.
2013-12-01
A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free
NASA Astrophysics Data System (ADS)
Popov, Anton; Kaus, Boris
2015-04-01
This software project aims at bringing the 3D lithospheric deformation modeling to a qualitatively different level. Our code LaMEM (Lithosphere and Mantle Evolution Model) is based on the following building blocks: * Massively-parallel data-distributed implementation model based on PETSc library * Light, stable and accurate staggered-grid finite difference spatial discretization * Marker-in-Cell pedictor-corector time discretization with Runge-Kutta 4-th order * Elastic stress rotation algorithm based on the time integration of the vorticity pseudo-vector * Staircase-type internal free surface boundary condition without artificial viscosity contrast * Geodynamically relevant visco-elasto-plastic rheology * Global velocity-pressure-temperature Newton-Raphson nonlinear solver * Local nonlinear solver based on FZERO algorithm * Coupled velocity-pressure geometric multigrid preconditioner with Galerkin coarsening Staggered grid finite difference, being inherently Eulerian and rather complicated discretization method, provides no natural treatment of free surface boundary condition. The solution based on the quasi-viscous sticky-air phase introduces significant viscosity contrasts and spoils the convergence of the iterative solvers. In LaMEM we are currently implementing an approximate stair-case type of the free surface boundary condition which excludes the empty cells and restores the solver convergence. Because of the mutual dependence of the stress and strain-rate tensor components, and their different spatial locations in the grid, there is no straightforward way of implementing the nonlinear rheology. In LaMEM we have developed and implemented an efficient interpolation scheme for the second invariant of the strain-rate tensor, that solves this problem. Scalable efficient linear solvers are the key components of the successful nonlinear problem solution. In LaMEM we have a range of PETSc-based preconditioning techniques that either employ a block factorization of
Rapid Calculation of Spacecraft Trajectories Using Efficient Taylor Series Integration
NASA Technical Reports Server (NTRS)
Scott, James R.; Martini, Michael C.
2011-01-01
A variable-order, variable-step Taylor series integration algorithm was implemented in NASA Glenn's SNAP (Spacecraft N-body Analysis Program) code. SNAP is a high-fidelity trajectory propagation program that can propagate the trajectory of a spacecraft about virtually any body in the solar system. The Taylor series algorithm's very high order accuracy and excellent stability properties lead to large reductions in computer time relative to the code's existing 8th order Runge-Kutta scheme. Head-to-head comparison on near-Earth, lunar, Mars, and Europa missions showed that Taylor series integration is 15.8 times faster than Runge- Kutta on average, and is more accurate. These speedups were obtained for calculations involving central body, other body, thrust, and drag forces. Similar speedups have been obtained for calculations that include J2 spherical harmonic for central body gravitation. The algorithm includes a step size selection method that directly calculates the step size and never requires a repeat step. High-order Taylor series integration algorithms have been shown to provide major reductions in computer time over conventional integration methods in numerous scientific applications. The objective here was to directly implement Taylor series integration in an existing trajectory analysis code and demonstrate that large reductions in computer time (order of magnitude) could be achieved while simultaneously maintaining high accuracy. This software greatly accelerates the calculation of spacecraft trajectories. At each time level, the spacecraft position, velocity, and mass are expanded in a high-order Taylor series whose coefficients are obtained through efficient differentiation arithmetic. This makes it possible to take very large time steps at minimal cost, resulting in large savings in computer time. The Taylor series algorithm is implemented primarily through three subroutines: (1) a driver routine that automatically introduces auxiliary variables and
ERIC Educational Resources Information Center
Yonka, Patricia
2006-01-01
This article discusses the formation of the Youth Visits the United Nations (YVUN) program. The program began in 2003 with funds provided by the Ursula Thrush Peace Seed Grant. Its purpose is to bring middle school students to New York to attend sessions of the United Nations, allowing these adolescents the opportunity to learn about global issues…
4th European Antibody Congress 2008
2009-01-01
The Fourth European Antibody meeting, organized by Terrapin Ltd., was held in Geneva, a center of the European biopharmaceutical industry. Merck-Serono, NovImmune, Pierre Fabre and Therapeomic are located nearby, as are R&D centers of Boehringer-Ingelheim, Novartis, Roche and Sanofi-Aventis. Over 40 speakers and more than 200 delegates attended the event. Companies represented included Abbott, Ablynx, Adnexus/ BMS, Astra-Zeneca/ CAT/ Medimmune, BiogenIdec, BioRad, Centocor (Johnson & Johnson), Crucell/DSM, Domantis, Dyax, Genmab, Genzyme, Glycart/ Roche, Haptogen, Immunogen, Kyowa-Kirin, LFB, Medarex, Merck-Serono, Micromet, Novartis, Pierre Fabre Laboratories, Roche, Sanofi-Aventis, Seattle-Genetics, Transgene, UCB Celltech and Wyeth. Other attendees included those based in academe or government (University of Amsterdam, University of Zurich, Univeristy Hospital-Lyon, Ecole Polytechnique Federale de Lausanne, INSERM, Tufts University, US National Institutes of Health), consultants, and patent attorneys (Edwards, Angell, Palmer & Dodge). The meeting was very interactive and included exchanges during the many scheduled networking times (exhibitions, speed-networking, lunches and evening receptions). The first day of the three day conference was dedicated to advances in understanding antibody structure-function relationships. Challenges and opportunities in antibody development were the focus of the second day and the third day featured discussion of innovative antibodies and antibody alternatives. PMID:20061813
Electronic Learning. Art: The 4th "R."
ERIC Educational Resources Information Center
Ohler, Jason
2001-01-01
With the Internet revolution in education, students are learning to think as designers and artists. The language of art must become the fourth "R," and students must become literate in this environment. The paper discusses art and the digital age and what teachers can do (rename art, hire more art teachers, and increase fourth-R literacy…
4th Annual Pharmacogenomics and Medicine Lectures.
Oestreicher, P
2001-08-01
In the future, pharmacogenomics will play an important role in the treatment of patients by making it possible to predict drug response based on an individual's genetic make-up. Similarly, pharmacogenomics may be used to reduce the probability that adverse effects will occur. The use of a patient's genetic information will lead to greater predictability in clinical outcomes and personalisation of medical care. Pharmacogenomic information can also aid in drug development by helping to select individuals that are likely to respond to a medication for participation in clinical trials. Integration of pharmacogenomics into the healthcare system has a number of potential economic benefits, including reduced costs of healthcare and drug discovery. The FDA has no specific plans to regulate therapy-guiding pharmacogenomic tests, which are different from diagnostic genetic tests. There are a number of ethical issues related to pharmacogenomics, including the credibility of the system for protecting the rights and welfare of human research subjects, general concerns about genetic research, privacy issues and equitable distribution of the technology. To ensure integration of pharmacogenomics into the healthcare system it will be important to obtain public support through education about the benefits and risks of this technology.
ERIC Educational Resources Information Center
Barnett, R. Michael
2013-01-01
After half a century of waiting, the drama was intense. Physicists slept overnight outside the auditorium to get seats for the seminar at the CERN lab in Geneva, Switzerland. Ten thousand miles away on the other side of the planet, at the world's most prestigious international particle physics conference, hundreds of physicists from every corner…
A positive finite-difference advection scheme
Hundsdorfer, W.; Koren, B.; Loon, M. van
1995-03-01
This paper examines a class of explicit finite-difference advection schemes derived along the method of lines. An important application field is large-scale atmospheric transport. The paper therefore focuses on the demand of positivity. For the spatial discretization, attention is confined to conservative schemes using five points per direction. The fourth-order central scheme and the family of {kappa}-schemes, comprising the second-order central, the second-order upwind, and the third-order upwind biased, are studied. Positivity is enforced through flux limiting. It is concluded that the limited third-order upwind discretization is the best candidate from the four examined. For the time integration attention is confined to a number of explicit Runge-Kutta methods of orders two to four. With regard to the demand of positivity, these integration methods turn out to behave almost equally and no best method could be identified. 16 refs., 4 figs., 4 tabs.
[Corneal higher order aberrations and their changes with aging].
Cermáková, S; Skorkovská, S
2010-12-01
Cornea is the most important refractive medium of the eye and affects its total aberration state. This paper deals with corneal higher order aberrations in healthy humans and evaluates their changes with aging and corneal curvature. The influence of the corneal anterior and posterior surfaces on aberrations of the whole cornea was also investigated. The examination was performed with a Scheimpflug camera which enables to examine the anterior and posterior corneal surface separately. The results show that higher order aberrations of the whole cornea are influenced mainly by the anterior surface aberrations. The main corneal higher order aberration is the Z (4,0) spherical aberration which has a positive value and increases with age. Also, 3rd order aberration values are of importance, especially coma which also increases with age. As a consequence, the root-mean-square of the 3rd and 4th order aberrations in elderly people has a higher value.
TVD: Total Variation Diminishing code
NASA Astrophysics Data System (ADS)
Pen, Ue-Li; Arras, Phil; Wong, ShingKwong
2013-04-01
TVD solves the magnetohydrodynamic (MHD) equations by updating the fluid variables along each direction using the flux-conservative, second-order, total variation diminishing (TVD), upwind scheme of Jin & Xin. The magnetic field is updated separately in two-dimensional advection-constraint steps. The electromotive force (EMF) is computed in the advection step using the TVD scheme, and this same EMF is used immediately in the constraint step in order to preserve \\Downtriangle B=0 without the need to store intermediate fluxes. The code is extended to three dimensions using operator splitting, and Runge-Kutta is used to get second-order accuracy in time. TVD offers high-resolution per grid cell, second-order accuracy in space and time, and enforcement of the \\Downtriangle B=0 constraint to machine precision. Written in Fortran, It has no memory overhead and is fast. It is also available in a fully scalable message-passing parallel MPI implementation.
Lie group analysis and similarity solution for fractional Blasius flow
NASA Astrophysics Data System (ADS)
Pan, Mingyang; Zheng, Liancun; Liu, Fawang; Zhang, Xinxin
2016-08-01
This paper presents an investigation for boundary layer flow of viscoelastic fluids past a flat plate. Fractional-order Blasius equation with spatial fractional Riemann-Liouville derivative is derived firstly by using Lie group transformation. The solution is obtained numerically by the generalized shooting method, employing the shifted Grünwald formula and classical fourth order Runge-Kutta method as the iterative scheme. The effects of the order of fractional derivative and the generalized Reynolds number on the velocity profiles are analyzed and discussed. Numerical results show that the smaller the value of the fractional order derivative leads to the faster velocity of viscoelastic fluids near the plate but not to hold near the outer flow. As the Reynolds number increases, the fluid is moving faster in the whole boundary layer consistently.
NASA Astrophysics Data System (ADS)
Garnier, Nicolas; Rolando, Christian; Høtje, Jakob Munk; Tokarski, Caroline
2009-07-01
This work presents the precise identification of triacylglycerols (TAGs) extracted from archaeological samples using a methodology based on nanoelectrospray and Fourier transform mass spectrometry. The archaeological TAG identification needs adapted sample preparation protocols to trace samples in advanced degradation state. More precisely, the proposed preparation procedure includes extraction of the lipid components from finely grinded ceramic using dichloromethane/methanol mixture with additional ultrasonication treatment, and TAG purification by solid phase extraction on a diol cartridge. Focusing on the analytical approach, the implementation of "in-house" species-dependent TAG database was investigated using MS and InfraRed Multiphoton Dissociation (IRMPD) MS/MS spectra; several vegetal oils, dairy products and animal fats were studied. The high mass accuracy of the Fourier transform analyzer ([Delta]m below 2.5 ppm) provides easier data interpretation, and allows distinction between products of different origins. In details, the IRMPD spectra of the lithiated TAGs reveal fragmentation reactions including loss of free neutral fatty acid and loss of fatty acid as [alpha],[beta]-unsaturated moieties. Based on the developed preparation procedure and on the constituted database, TAG extracts from 5th century BC to 4th century AD Olbia lamps were analyzed. The structural information obtained succeeds in identifying that bovine/ovine fats were used as fuel used in these archaeological Olbia lamps.
2012-01-01
From November 4th- 6th 2011, the 3rd NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Like in the previous years, the meeting provided an excellent platform for scientific exchange and the presentation of innovative projects for young colleagues in the fields of neurovascular research, neuroinflammation and neurodegeneration. As kick-off to the scientific sessions, Reinhard Hohlfeld, Head of the Institute for Clinical Neuroimmunology in Munich, gave an illustrious overview on the many fascinations of neuroimmunologic research. A particular highlight on the second day of the meeting was the award of the 1'st NEUROWIND e.V. prize for young academics in the field of experimental neurology. This award is posted for young colleagues under the age of 35 with a significant achievement in the field of neurovascular research, neuroinflammation or neurodegeneration and comprises an amount of 20.000 Euro, founded by Merck Serono GmbH, Darmstadt. Germany. The first prize was awarded to Ivana Nikic from Martin Kerschensteiner's group in Munich for her brilliant work on a reversible form of axon damage in experimental autoimmune encephalomyelitis and multiple sclerosis, published in Nature Medicine in 2011. This first prize award ceremony was a great incentive for the next call for proposals now upcoming in 2012. PMID:22360825
Bailey, D L; Pichler, B J; Gückel, B; Barthel, H; Beer, A J; Bremerich, J; Czernin, J; Drzezga, A; Franzius, C; Goh, V; Hartenbach, M; Iida, H; Kjaer, A; la Fougère, C; Ladefoged, C N; Law, I; Nikolaou, K; Quick, H H; Sabri, O; Schäfer, J; Schäfers, M; Wehrl, H F; Beyer, T
2015-10-01
This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both technical versatility and acceptance by clinical and research-driven users from the status quo of last year. Still, with only minimal evidence of progress made in exploiting the true complementary nature of the PET and MRI-based information, PET/MRI is still yet to achieve its potential. In that regard, the conclusion of last year's meeting "the real work has just started" still holds true.
Qayyum, Mubashir; Khan, Hamid; Rahim, M. Tariq; Ullah, Inayat
2015-01-01
The aim of this article is to model and analyze an unsteady axisymmetric flow of non-conducting, Newtonian fluid squeezed between two circular plates passing through porous medium channel with slip boundary condition. A single fourth order nonlinear ordinary differential equation is obtained using similarity transformation. The resulting boundary value problem is solved using Homotopy Perturbation Method (HPM) and fourth order Explicit Runge Kutta Method (RK4). Convergence of HPM solution is verified by obtaining various order approximate solutions along with absolute residuals. Validity of HPM solution is confirmed by comparing analytical and numerical solutions. Furthermore, the effects of various dimensionless parameters on the longitudinal and normal velocity profiles are studied graphically. PMID:25738864
Application of traditional CFD methods to nonlinear computational aeroacoustics problems
NASA Technical Reports Server (NTRS)
Chyczewski, Thomas S.; Long, Lyle N.
1995-01-01
This paper describes an implementation of a high order finite difference technique and its application to the category 2 problems of the ICASE/LaRC Workshop on Computational Aeroacoustics (CAA). Essentially, a popular Computational Fluid Dynamics (CFD) approach (central differencing, Runge-Kutta time integration and artificial dissipation) is modified to handle aeroacoustic problems. The changes include increasing the order of the spatial differencing to sixth order and modifying the artificial dissipation so that it does not significantly contaminate the wave solution. All of the results were obtained from the CM5 located at the Numerical Aerodynamic Simulation Laboratory. lt was coded in CMFortran (very similar to HPF), using programming techniques developed for communication intensive large stencils, and ran very efficiently.
A regularized model for impact in explicit dynamics applied to the split Hopkinson pressure bar
NASA Astrophysics Data System (ADS)
Otto, Peter; De Lorenzis, Laura; Unger, Jörg F.
2016-07-01
In the numerical simulation of impact phenomena, artificial oscillations can occur due to an instantaneous change of velocity in the contact area. In this paper, a nonlinear penalty regularization is used to avoid these oscillations. A particular focus is the investigation of higher order methods in space and time to increase the computational efficiency. The spatial discretization is realized by higher order spectral element methods that are characterized by a diagonal mass matrix. The time integration scheme is based on half-explicit Runge-Kutta scheme of fourth order. For the conditionally stable scheme, the critical time step is influenced by the penalty regularization. A framework is presented to adjust the penalty stiffness and the time step for a specific mesh to avoid oscillations. The methods presented in this paper are applied to 1D-simulations of a split Hopkinson pressure bar, which is commonly used for the investigation of materials under dynamic loading.
The Local Discontinuous Galerkin Method for Time-Dependent Convection-Diffusion Systems
NASA Technical Reports Server (NTRS)
Cockburn, Bernardo; Shu, Chi-Wang
1997-01-01
In this paper, we study the Local Discontinuous Galerkin methods for nonlinear, time-dependent convection-diffusion systems. These methods are an extension of the Runge-Kutta Discontinuous Galerkin methods for purely hyperbolic systems to convection-diffusion systems and share with those methods their high parallelizability, their high-order formal accuracy, and their easy handling of complicated geometries, for convection dominated problems. It is proven that for scalar equations, the Local Discontinuous Galerkin methods are L(sup 2)-stable in the nonlinear case. Moreover, in the linear case, it is shown that if polynomials of degree k are used, the methods are k-th order accurate for general triangulations; although this order of convergence is suboptimal, it is sharp for the LDG methods. Preliminary numerical examples displaying the performance of the method are shown.
A regularized model for impact in explicit dynamics applied to the split Hopkinson pressure bar
NASA Astrophysics Data System (ADS)
Otto, Peter; De Lorenzis, Laura; Unger, Jörg F.
2016-10-01
In the numerical simulation of impact phenomena, artificial oscillations can occur due to an instantaneous change of velocity in the contact area. In this paper, a nonlinear penalty regularization is used to avoid these oscillations. A particular focus is the investigation of higher order methods in space and time to increase the computational efficiency. The spatial discretization is realized by higher order spectral element methods that are characterized by a diagonal mass matrix. The time integration scheme is based on half-explicit Runge-Kutta scheme of fourth order. For the conditionally stable scheme, the critical time step is influenced by the penalty regularization. A framework is presented to adjust the penalty stiffness and the time step for a specific mesh to avoid oscillations. The methods presented in this paper are applied to 1D-simulations of a split Hopkinson pressure bar, which is commonly used for the investigation of materials under dynamic loading.
RAISHIN: A High-Resolution Three-Dimensional General Relativistic Magnetohydrodynamics Code
NASA Technical Reports Server (NTRS)
Mizuno, Yosuke; Nishikawa, Ken-Ichi; Koide, Shinji; Hardee, Philip; Fishman, Gerald J.
2006-01-01
We have developed a new three-dimensional general relativistic magnetohydrodynamic (GRMHD) code, RAISHIN, using a conservative, high resolution shock-capturing scheme. The numerical fluxes are calculated using the Harten, Lax, & van Leer (HLL) approximate Riemann solver scheme. The flux-interpolated, constrained transport scheme is used to maintain a divergence-free magnetic field. In order to examine the numerical accuracy and the numerical efficiency, the code uses four different reconstruction methods: piecewise linear methods with Minmod and MC slope-limiter function, convex essentially non-oscillatory (CENO) method, and piecewise parabolic method (PPM) using multistep TVD Runge-Kutta time advance methods with second and third-order time accuracy. We describe code performance on an extensive set of test problems in both special and general relativity. Our new GRMHD code has proven to be accurate in second order and has successfully passed with all tests performed, including highly relativistic and magnetized cases in both special and general relativity.
A new approach to constructing efficient stiffly accurate EPIRK methods
NASA Astrophysics Data System (ADS)
Rainwater, G.; Tokman, M.
2016-10-01
The structural flexibility of the exponential propagation iterative methods of Runge-Kutta type (EPIRK) enables construction of particularly efficient exponential time integrators. While the EPIRK methods have been shown to perform well on stiff problems, all of the schemes proposed up to now have been derived using classical order conditions. In this paper we extend the stiff order conditions and the convergence theory developed for the exponential Rosenbrock methods to the EPIRK integrators. We derive stiff order conditions for the EPIRK methods and develop algorithms to solve them to obtain specific schemes. Moreover, we propose a new approach to constructing particularly efficient EPIRK integrators that are optimized to work with an adaptive Krylov algorithm. We use a set of numerical examples to illustrate the computational advantages that the newly constructed EPIRK methods offer compared to previously proposed exponential integrators.
Dynamic Simulation of Batch Photocatalytic Reactor (BPR) for Wastewater Treatment
NASA Astrophysics Data System (ADS)
Dutta, Suman
2012-08-01
Reactive dyes discharged from dyehouse causes a serious environmental problem. UV/TiO2 photocatalysis has been employed effectively for these organic dyes removal from dye-house effluent. This process produces less amount of non-toxic final product. In this paper a photocatalytic reactor has been designed for Reactive red 198 (RR198) removal from aqueous solution. The reactor is operating in batch mode. After each batch, TiO2 catalyst has been separated and recycled in the next batch. Mathematical model equation of this batch photocatalytic reactor (BPR) has been developed considering Langmuir-Hinshelwood kinetics. Simulation of BPR has been carried out using fourth order Runge-Kutta (RK) method and fifth order RK method (Butcher method). This simulation results can be used to develop an automatic photocatlytic reactor for industrial wastewater treatment. Catalyst activity decay and its effect on each batch have been incorporated in this model.
Numerical investigation of chemically reacting flows in ramjet dump combustors
NASA Technical Reports Server (NTRS)
Hsieh, Kwang-Chung; Liu, Jong-Shang
1989-01-01
The time-dependent Navier-Stokes equations, including second-order turbulence model, are numerically integrated by using four-stage Runge-Kutta scheme to predict the steady-state supersonic flow structures in ramjet dump combustors. The formulation is derived for reacting flows with finite-rate chemistry. In the present study, it is firstly attempted to assess the accuracy of existing high-order turbulence model in supersonic flows. The comparison shows reasonable agreement between calculated and measured data in terms of velocity distributions. It is indicated that a modified constant C-mu for calculating turbulent eddy viscosity is needed in the supersonic flow regime and the adaptive meshing is preferred to capture the recirculation zone. In the reacting flow calculation, the results from a test case of hydrogen and air combustion at premixed conditon show that the rearward facing step is able to increase flow residence time and stabilize the flame in supersonic flows.
Optimal control and sensitivity analysis of an influenza model with treatment and vaccination.
Tchuenche, J M; Khamis, S A; Agusto, F B; Mpeshe, S C
2011-03-01
We formulate and analyze the dynamics of an influenza pandemic model with vaccination and treatment using two preventive scenarios: increase and decrease in vaccine uptake. Due to the seasonality of the influenza pandemic, the dynamics is studied in a finite time interval. We focus primarily on controlling the disease with a possible minimal cost and side effects using control theory which is therefore applied via the Pontryagin's maximum principle, and it is observed that full treatment effort should be given while increasing vaccination at the onset of the outbreak. Next, sensitivity analysis and simulations (using the fourth order Runge-Kutta scheme) are carried out in order to determine the relative importance of different factors responsible for disease transmission and prevalence. The most sensitive parameter of the various reproductive numbers apart from the death rate is the inflow rate, while the proportion of new recruits and the vaccine efficacy are the most sensitive parameters for the endemic equilibrium point.
Mathematical and computational model for the analysis of micro hybrid rocket motor
NASA Astrophysics Data System (ADS)
Stoia-Djeska, Marius; Mingireanu, Florin
2012-11-01
The hybrid rockets use a two-phase propellant system. In the present work we first develop a simplified model of the coupling of the hybrid combustion process with the complete unsteady flow, starting from the combustion port and ending with the nozzle. The physical and mathematical model are adapted to the simulations of micro hybrid rocket motors. The flow model is based on the one-dimensional Euler equations with source terms. The flow equations and the fuel regression rate law are solved in a coupled manner. The platform of the numerical simulations is an implicit fourth-order Runge-Kutta second order cell-centred finite volume method. The numerical results obtained with this model show a good agreement with published experimental and numerical results. The computational model developed in this work is simple, computationally efficient and offers the advantage of taking into account a large number of functional and constructive parameters that are used by the engineers.
Optimal control and sensitivity analysis of an influenza model with treatment and vaccination.
Tchuenche, J M; Khamis, S A; Agusto, F B; Mpeshe, S C
2011-03-01
We formulate and analyze the dynamics of an influenza pandemic model with vaccination and treatment using two preventive scenarios: increase and decrease in vaccine uptake. Due to the seasonality of the influenza pandemic, the dynamics is studied in a finite time interval. We focus primarily on controlling the disease with a possible minimal cost and side effects using control theory which is therefore applied via the Pontryagin's maximum principle, and it is observed that full treatment effort should be given while increasing vaccination at the onset of the outbreak. Next, sensitivity analysis and simulations (using the fourth order Runge-Kutta scheme) are carried out in order to determine the relative importance of different factors responsible for disease transmission and prevalence. The most sensitive parameter of the various reproductive numbers apart from the death rate is the inflow rate, while the proportion of new recruits and the vaccine efficacy are the most sensitive parameters for the endemic equilibrium point. PMID:20140696
Study of lower hybrid wave propagation in ionized gas by Hamiltonian theory
Casolari, A.; Cardinali, A.
2014-02-12
In order to find an approximate solution to the Vlasov-Maxwell equation system describing the lower hybrid wave propagation in magnetic confined plasmas, the use of the WKB method leads to the ray tracing equations. The Hamiltonian character of the ray tracing equations is investigated analytically and numerically in order to deduce the physical properties of the wave propagating without absorption in the confined plasma. The consequences of the Hamiltonian character of the equations on the travelling wave, in particular, on the evolution of the parallel wavenumber along the propagation path have been accounted and the chaotic diffusion of the timeaveraged parallel wave-number towards higher values has been evaluated. Numerical analysis by means of a Runge-Kutta based algorithm implemented in a ray tracing code supplies the analytical considerations. A numerical tool based on the symplectic integration of the ray trajectories has been developed.
Semi-implicit spectral deferred correction methods for ordinary differential equations
Minion, Michael L.
2002-10-06
A semi-implicit formulation of the method of spectral deferred corrections (SISDC) for ordinary differential equations with both stiff and non-stiff terms is presented. Several modifications and variations to the original spectral deferred corrections method by Dutt, Greengard, and Rokhlin concerning the choice of integration points and the form of the correction iteration are presented. The stability and accuracy of the resulting ODE methods are explored analytically and numerically. The SISDC methods are intended to be combined with the method of lines approach to yield a flexible framework for creating higher-order semi-implicit methods for partial differential equations. A discussion and numerical examples of the SISDC method applied to advection-diffusion type equations are included. The results suggest that higher-order SISDC methods are more efficient than semi-implicit Runge-Kutta methods for moderately stiff problems in terms of accuracy per function evaluation.
Droplet Deformation Prediction with the Droplet Deormation and Break Up Model (DDB)
NASA Technical Reports Server (NTRS)
Vargas, Mario
2012-01-01
The Droplet Deformation and Breakup Model was used to predict deformation of droplets approaching the leading edge stagnation line of an airfoil. The quasi-steady model was solved for each position along the droplet path. A program was developed to solve the non-linear, second order, ordinary differential equation that governs the model. A fourth order Runge-Kutta method was used to solve the equation. Experimental slip velocities from droplet breakup studies were used as input to the model which required slip velocity along the particle path. The center of mass displacement predictions were compared to the experimental measurements from the droplet breakup studies for droplets with radii in the range of 200 to 700 mm approaching the airfoil at 50 and 90 m/sec. The model predictions were good for the displacement of the center of mass for small and medium sized droplets. For larger droplets the model predictions did not agree with the experimental results.
Droplet Deformation Prediction With the Droplet Deformation and Breakup Model (DDB)
NASA Technical Reports Server (NTRS)
Vargas, Mario
2012-01-01
The Droplet Deformation and Breakup Model was used to predict deformation of droplets approaching the leading edge stagnation line of an airfoil. The quasi-steady model was solved for each position along the droplet path. A program was developed to solve the non-linear, second order, ordinary differential equation that governs the model. A fourth order Runge-Kutta method was used to solve the equation. Experimental slip velocities from droplet breakup studies were used as input to the model which required slip velocity along the particle path. The center of mass displacement predictions were compared to the experimental measurements from the droplet breakup studies for droplets with radii in the range of 200 to 700 mm approaching the airfoil at 50 and 90 m/sec. The model predictions were good for the displacement of the center of mass for small and medium sized droplets. For larger droplets the model predictions did not agree with the experimental results.
Dynamical analysis of the avian-human influenza epidemic model using the semi-analytical method
NASA Astrophysics Data System (ADS)
Jabbari, Azizeh; Kheiri, Hossein; Bekir, Ahmet
2015-03-01
In this work, we present a dynamic behavior of the avian-human influenza epidemic model by using efficient computational algorithm, namely the multistage differential transform method(MsDTM). The MsDTM is used here as an algorithm for approximating the solutions of the avian-human influenza epidemic model in a sequence of time intervals. In order to show the efficiency of the method, the obtained numerical results are compared with the fourth-order Runge-Kutta method (RK4M) and differential transform method(DTM) solutions. It is shown that the MsDTM has the advantage of giving an analytical form of the solution within each time interval which is not possible in purely numerical techniques like RK4M.
The stochastic modeling of the short-time variations of the galactic cosmic rays
NASA Astrophysics Data System (ADS)
Wawrzynczak, A.; Modzelewska, R.
2016-08-01
We present the stochastic model of the galactic cosmic ray (GCR) particles transport in the heliosphere. The model is created based on the numerical solution of the Parker transport equation (PTE) describing the non-stationary transport of charged particles in the turbulent medium. We present the numerical schemes for the strong order integration of the set of the stochastic differential equations (SDEs) corresponding to the non-stationary PTE. Among the employed methods are the strong order Euler-Maruyama, Milstein and stochastic Runge- Kutta methods. We perform the selection of the method resulting in the highest agreement of the model of the 27-day variation of the GCR intensity with the experimental observations.
77 FR 48960 - Order Renewing Order Temporarily Denying Export Privileges
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-15
... Aviation a/k/a GIE Zarand Aviation, 42 Avenue Montaigne, 75008 Paris, France; and 112 Avenue Kleber, 75116 Paris, France; Gatewick LLC, a/k/a Gatewick Freight & Cargo Services a/k/a/Gatewick Aviation Services, G..., Paris, France; Sirjanco Trading, P.O. Box 8709, Dubai, United Arab Emirates; Ali Eslamian, 4th Floor,...
Bieniosek, F.M.; Barnard, J.J.; Henestroza, E.; Logan, B.G.; Lidia, S.; More, R.M.; Ni, P.A.; Seidl, P.A.; Vay, J.-L.; Grote, D.; Friedman, A.
2009-09-30
This milestone has been met. The effort contains two main components: (1) Experimental results of warm dense matter target experiments on optimized NDCX-I configurations that include measurements of target temperature and transient target behavior. (2) A theoretical model of the target response to beam heating that includes an equilibrium heating model of the target foil and a model for droplet formation in the target for comparison with experimental results. The experiments on ion-beam target heating use a 300-350-keV K{sup +} pulsed beam from the Neutralized Compression Drift Experiment (NDCX-I) accelerator at LBNL. The NDCX-I accelerator delivers an uncompressed pulse beam of several microseconds with a typical power density of >100 kW/cm{sup 2} over a final focus spot size of about 1 mm. An induction bunching module the NDCX-I compresses a portion of the beam pulse to reach a much higher power density over 2 nanoseconds. Under these conditions the free-standing foil targets are rapidly heated to temperatures to over 4000 K. We model the target thermal dynamics using the equation of heat conduction for the temperature T(x,t) as a function of time (t) and spatial dimension along the beam direction (x). The competing cooling processes release energy from the surface of the foil due to evaporation, radiation, and thermionic (Richardson) emission. A description of the experimental configuration of the target chamber and results from initial beam-target experiments are reported in our FY08 4th Quarter and FY09 2nd Quarter Milestone Reports. The WDM target diagnostics include a high-speed multichannel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. The fast optical pyrometer is a unique and significant new diagnostic which provides valuable information on the temperature evolution of the heated target.
NASA Astrophysics Data System (ADS)
Zamani, N.; Keshavarz, A.; Nadgaran, H.
2016-06-01
In this paper, we investigate the optical absorption coefficient of hybrid structure consisting of metal nano particle (MNP) coupled to multi-layer spherical quantum dot (MSQD). Energy eigenvalues and eigenfunctions of Schrödinger equation in this structure are obtained by using numerical solution (by the fourth-order Runge-Kutta method). The effect of MNP in the vicinity of MSQD is calculated by considering local field theory. Then the variation of optical absorption coefficient hybrid structure is calculated. The results show that the presence of MNP near MSQD enhances the optical absorption coefficient. Also, by changing the distance between MNP and MSQD and radius of MNP, variation of optical absorption coefficient and refractive index changes are introduced.
NASA Technical Reports Server (NTRS)
Kirk, R. G.; Gunter, E. J.
1972-01-01
A steady state analysis of the shaft and the bearing housing motion was made by assuming synchronous precession of the system. The conditions under which the support system would act as a dynamic vibration absorber at the rotor critical speed were studied; plots of the rotor and support amplitudes, phase angles, and forces transmitted were evaluated by the computer, and the performance curves were automatically plotted by a CalComp plotter unit. Curves are presented on the optimization of the support housing characteristics to attenuate the rotor unbalance response over the entire rotor speed range. The complete transient motion including rotor unbalance was examined by integrating the equations of motion numerically using a modified fourth order Runge-Kutta procedure, and the resulting whirl orbits were plotted by the CalComp plotter unit. The results of the transient analysis are discussed with regards to the design optimization procedure derived from the steady-state analysis.
NASA Astrophysics Data System (ADS)
Krishnamurthy, M. R.; Gireesha, B. J.; Prasannakumara, B. C.; Gorla, Rama Subba Reddy
2016-09-01
A theoretically investigation has been performed to study the effects of thermal radiation and chemical reaction on MHD velocity slip boundary layer flow and melting heat transfer of nanofluid induced by a nonlinear stretching sheet. The Brownian motion and thermophoresis effects are incorporated in the present nanofluid model. A set of proper similarity variables is used to reduce the governing equations into a system of nonlinear ordinary differential equations. An efficient numerical method like Runge-Kutta-Fehlberg-45 order is used to solve the resultant equations for velocity, temperature and volume fraction of the nanoparticle. The effects of different flow parameters on flow fields are elucidated through graphs and tables. The present results have been compared with existing one for some limiting case and found excellent validation.
Campo, A.; Tebeest, K.; Lacoa, U.; Morales, J.C.
1996-10-01
A semianalytic analysis of in-tube turbulent forced convection is performed whose special computational feature is the combination of the method of lines, the finite volume technique, and a radial coordinate transformation. First, a numerical solution of the momentum equation was obtained by a simple Runge-Kutta integration scheme. Second, the energy equation was reformulated into a system of ordinary differential equations of first order. Each equation in the system controls the temperature along a line in a mesh consisting of concentric lines. Reliable analytic solutions for the temperature distribution of fluids in the region of thermal development can be determined for combinations of Reynolds and Prandtl numbers. Predicted results for the distributions of mean bulk temperature and local Nusselt numbers for air, water, and oils compare satisfactorily with the available experimental data.
NASA Astrophysics Data System (ADS)
Aggarwal, Anil Kr.; Kumar, Sanjeev; Singh, Vikram
2016-08-01
The binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman-Kolmogorov differential equations. These governing differential equations are solved with Runge-Kutta fourth-order method.
NASA Astrophysics Data System (ADS)
Babu, D. Harish; Narayana, P. V. Satya
2016-08-01
An analysis has been carried out to study the Joule heating effect on MHD heat transfer of an incompressible Jeffrey fluid due to a stretching porous sheet with power law heat flux and heat source. A constant magnetic field is applied normal to the stretching surface. The basic governing equations are reduced into the coupled nonlinear ordinary differential equations by using similarity transformations. The resulting equations are then solved numerically by shooting method with fourth order Runge-Kutta scheme. The effects of various physical parameters entering into the problem on dimensionless velocity and temperature distribution are discussed through graphs and tables. The results reveal that the momentum and thermal boundary layer thickness are significantly influenced by Deborah number (β), ratio of relaxation and retardation times parameter (λ), heat generation parameter (β*), Eckert number (Ec) and magnetic field parameter (M). A comparison with the previously published works shows excellent agreement.