Science.gov

Sample records for 4th order runge-kutta

  1. Using 4th order Runge-Kutta method for solving a twisted Skyrme string equation

    NASA Astrophysics Data System (ADS)

    Hadi, Miftachul; Anderson, Malcolm; Husein, Andri

    2016-03-01

    We study numerical solution, especially using 4th order Runge-Kutta method, for solving a twisted Skyrme string equation. We find numerically that the value of minimum energy per unit length of vortex solution for a twisted Skyrmion string is 20.37 × 1060 eV/m.

  2. A Generalized 4th-Order Runge-Kutta Method for the Gross-Pitaevskii Equation

    NASA Astrophysics Data System (ADS)

    Kandes, Martin

    2015-04-01

    We present the implementation of a method-of-lines approach for numerically approximating solutions of the time-dependent Gross-Pitaevksii equation in non-uniformly rotating reference frames. Implemented in parallel using a hybrid MPI + OpenMP framework, which will allow for scalable, high-resolution numerical simulations, we utilize an explicit, generalized 4th-order Runge-Kutta time-integration scheme with 2nd- and 4th-order central differences to approximate the spatial derivatives in the equation. The principal objective of this project is to model the effect(s) of inertial forces on quantized vortices within weakly-interacting dilute atomic gas Bose-Einstein condensates in the mean-field limit of the Gross-Pitaevskii equation. Here, we discuss our work-to-date and preliminary results.

  3. A third order Runge-Kutta algorithm on a manifold

    NASA Technical Reports Server (NTRS)

    Crouch, P. E.; Grossman, R. G.; Yan, Y.

    1992-01-01

    A third order Runge-Kutta type algorithm is described with the property that it preserves certain geometric structures. In particular, if the algorithm is initialized on a Lie group, then the resulting iterates remain on the Lie group.

  4. 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.

  5. Diagonally Implicit Symplectic Runge-Kutta Methods with High Algebraic and Dispersion Order

    PubMed Central

    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

  6. Implicit High Order Strong Stability Preserving Runge-Kutta Time Discretizations

    DTIC Science & Technology

    2009-02-05

    ods and the algebraically stable methods, respectively) are unconditionally stable. 3. The implicit SSP Runge-Kutta of order p > 1 have an SSP...coefficient that is not dramatically larger than those for explicit methods [15, 3, 12]. 4. Any SSP method must have stage order p < 2, and explicit...Runge-Kutta method must have stage order p < 1. The stage order p is a lower bound on the order of convergence when a method is applied to arbitrarily

  7. A fourth order modified trigonometrically fitted symplectic Runge-Kutta-Nyström method

    NASA Astrophysics Data System (ADS)

    Kalogiratou, Z.; Monovasilis, Th.; Simos, T. E.

    2013-10-01

    In this work we construct a modified trigonometrically fitted symplectic Runge Kutta Nyström method based on the forth order five stages method of Calvo and Sanz-Serna. We apply the new method on the numerical integration of the two-body problem.

  8. Fourth-order 2N-storage Runge-Kutta schemes

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Kennedy, Christopher A.

    1994-01-01

    A family of five-stage fourth-order Runge-Kutta schemes is derived; these schemes required only two storage locations. A particular scheme is identified that has desirable efficiency characteristics for hyperbolic and parabolic initial (boundary) value problems. This scheme is competitive with the classical fourth-order method (high-storage) and is considerably more efficient and accurate than existing third-order low-storage schemes.

  9. A fourth order modified trigonometrically fitted symplectic Runge-Kutta-Nyström method

    NASA Astrophysics Data System (ADS)

    Kalogiratou, Z.; Monovasilis, Th.; Simos, T. E.

    2014-12-01

    In this work we construct a modified trigonometrically fitted symplectic Runge Kutta Nyström method based on the fourth order five stages method of Calvo and Sanz-Serna (1994). We apply the new method on the numerical integration of the two-dimensional harmonic oscillator, the two-body problem, a perturbed two-body problem and two two-dimensional nonlinear oscillatory Hamiltonian systems.

  10. Singly implicit diagonally extended Runge-Kutta methods of fourth order

    NASA Astrophysics Data System (ADS)

    Skvortsov, L. M.

    2014-05-01

    Singly implicit diagonally extended Runge-Kutta methods make it possible to combine the merits of diagonally implicit methods (namely, the simplicity of implementation) and fully implicit ones (high stage order). Due to this combination, they can be very efficient at solving stiff and differential-algebraic problems. In this paper, fourth-order methods with an explicit first stage are examined. The methods have the third or fourth stage order. Consideration is given to an efficient implementation of these methods. The results of tests in which the proposed methods were compared with the fifth-order RADAU IIA method are presented.

  11. Behaviour of extrapolated implicit order-2 Runge-Kutta methods with and without compensated summation

    NASA Astrophysics Data System (ADS)

    Ismail, Amira; Gorgey, Annie

    2015-10-01

    Extrapolation involves taking a certain linear combination of the numerical solutions of a base method applied with different stepsizes to obtain greater accuracy. This linear combination is done so as to eliminate the leading error term. The technique of extrapolation in accelerating convergence has been successfully in numerical solution of ordinary differential equations. In this study, symmetric Runge-Kutta methods for solving linear and nonlinear stiff problem are considered. Symmetric methods admit asymptotic error expansion in even powers of the stepsize and are therefore of special interest because successive extrapolations can increase the order by two at time. Although extrapolation can give greater accuracy, due to the stepsize chosen, the numerical approximations are often destroy due to the accumulated round off errors. Therefore, it is important to control the rounding errors especially when applying extrapolation. One way to minimize round off errors is by applying compensated summation. In this paper, the numerical results are given for the symmetric Runge-Kutta methods Implicit Midpoint and Implicit Trapezoidal Rule applied with and without compensated summation. The result shows that symmetric methods with higher level extrapolation using compensated summation gives much smaller errors. On the other hand, symmetric methods without compensated summation when applied with extrapolation, the errors are affected badly by rounding errors.

  12. Optimal Runge-Kutta Schemes for High-order Spatial and Temporal Discretizations

    DTIC Science & Technology

    2015-06-01

    combinations. The predictive nature of the von Neumann analysis is then validated through the exploration of the convection of acoustic waves in one...through the exploration of the convection of acoustic waves in one dimension and an isentropic vortex in three dimensions. Is is shown that the...are then shown to extend readily to real world flows in the form of a convecting isentropic vortex. Explicit Runge-Kutta time integrators may seem to

  13. A fourth-order Runge-Kutta in the interaction picture method for numerically solving the coupled nonlinear Schrodinger equation.

    PubMed

    Zhang, Zhongxi; Chen, Liang; Bao, Xiaoyi

    2010-04-12

    A fourth-order Runge-Kutta in the interaction picture (RK4IP) method is presented for solving the coupled nonlinear Schr odinger equation (CNLSE) that governs the light propagation in optical fibers with randomly varying birefringence. The computational error of RK4IP is caused by the fourth-order Runge-Kutta algorithm, better than the split-step approximation limited by the step size. As a result, the step size of RK4IP can have the same order of magnitude as the dispersion length and/or the nonlinear length of the fiber, provided the birefringence effect is small. For communication fibers with random birefringence, the step size of RK4IP can be orders of magnitude larger than the correlation length and the beating length of the fibers, depending on the interaction between linear and nonlinear effects. Our approach can be applied to the fibers having the general form of local birefringence and treat the Kerr nonlinearity without approximation. Our RK4IP results agree well with those obtained from Manakov-PMD approximation, provided the polarization state can be mixed enough on the Poincar e sphere.

  14. Symplectic partitioned Runge-Kutta method based on the eighth-order nearly analytic discrete operator and its wavefield simulations

    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

  15. Simulation Study on Effects of Order and Step Size of Runge-Kutta Methods that Solve Contagious Disease and Tumor Models.

    PubMed

    Z, Wang; Q, Wang; Dj, Klinke

    2016-09-01

    Biological processes such as contagious disease spread patterns and tumor growth dynamics are modelled using a set of coupled differential equations. Experimental data is usually used to calibrate models so they can be used to make future predictions. In this study, numerical methods were implemented to approximate solutions to mathematical models that were not solvable analytically, such as a SARS model. More complex models such as a tumor growth model involve high-dimensional parameter spaces; efficient numerical simulation techniques were used to search for optimal or close-to-optimal parameter values in the equations. Runge-Kutta methods are a group of explicit and implicit numerical methods that effectively solve the ordinary differential equations in these models. Effects of the order and the step size of Runge-Kutta methods were studied in order to maximize the search accuracy and efficiency in parameter spaces of the models. Numerical simulation results showed that an order of four gave the best balance between truncation errors and the simulation speed for SIR, SARS, and tumormodels studied in the project. The optimal step size for differential equation solvers was found to be model-dependent.

  16. Extrapolated stabilized explicit Runge-Kutta methods

    NASA Astrophysics Data System (ADS)

    Martín-Vaquero, J.; Kleefeld, B.

    2016-12-01

    Extrapolated Stabilized Explicit Runge-Kutta methods (ESERK) are proposed to solve multi-dimensional nonlinear partial differential equations (PDEs). In such methods it is necessary to evaluate the function nt times per step, but the stability region is O (nt2). Hence, the computational cost is O (nt) times lower than for a traditional explicit algorithm. In that way stiff problems can be integrated by the use of simple explicit evaluations in which case implicit methods usually had to be used. Therefore, they are especially well-suited for the method of lines (MOL) discretizations of parabolic nonlinear multi-dimensional PDEs. In this work, first s-stages first-order methods with extended stability along the negative real axis are obtained. They have slightly shorter stability regions than other traditional first-order stabilized explicit Runge-Kutta algorithms (also called Runge-Kutta-Chebyshev codes). Later, they are used to derive nt-stages second- and fourth-order schemes using Richardson extrapolation. The stability regions of these fourth-order codes include the interval [ - 0.01nt2, 0 ] (nt being the number of total functions evaluations), which are shorter than stability regions of ROCK4 methods, for example. However, the new algorithms neither suffer from propagation of errors (as other Runge-Kutta-Chebyshev codes as ROCK4 or DUMKA) nor internal instabilities. Additionally, many other types of higher-order (and also lower-order) methods can be obtained easily in a similar way. These methods also allow adaptation of the length step with no extra cost. Hence, the stability domain is adapted precisely to the spectrum of the problem at the current time of integration in an optimal way, i.e., with minimal number of additional stages. We compare the new techniques with other well-known algorithms with good results in very stiff diffusion or reaction-diffusion multi-dimensional nonlinear equations.

  17. Composite group of explicit Runge-Kutta methods

    NASA Astrophysics Data System (ADS)

    Hamid, Fatin Nadiah Abd; Rabiei, Faranak; Ismail, Fudziah

    2016-06-01

    In this paper,the composite groups of Runge-Kutta (RK) method are proposed. The composite group of RK method of third and second order, RK3(2) and fourth and third order RK4(3) base on classical Runge-Kutta method are derived. The proposed methods are two-step in nature and have less number of function evaluations compared to the existing Runge-Kutta method. The order conditions up to order four are obtained using rooted trees and composite rule introduced by J. C Butcher. The stability regions of RK3(2) and RK4(3) methods are presented and initial value problems of first order ordinary differential equations are carried out. Numerical results are compared with existing Runge-Kutta method.

  18. 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.

  19. Some procedures for the construction of high-order exponentially fitted Runge-Kutta-Nyström methods of explicit type

    NASA Astrophysics Data System (ADS)

    Franco, J. M.; Gómez, I.

    2013-04-01

    The construction of high-order exponentially fitted Runge-Kutta-Nyström (EFRKN) methods of explicit type for the numerical solution of oscillatory differential systems is analyzed. Based on two basic symmetric and symplectic EFRKN methods of reference we present two procedures for constructing high-order explicit methods. The first procedure is based on composition methods and it allows the construction of high-order explicit EFRKN methods which are symmetric and symplectic. The second procedure is based on combining different EFRKN methods in order to construct embedded pairs of explicit parallel EFRKN methods which can be implemented in variable-step codes without additional cost. The numerical experiments carried out show the qualitative behavior and the efficiency of the new EFRKN methods when they are compared with some standard methods proposed in the scientific literature for solving second-order nonstiff differential systems. Catalogue identifier: AEOO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOO_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License No. of lines in distributed program, including test data, etc.: 2527 No. of bytes in distributed program, including test data, etc.: 107433 Distribution format: tar.gz Programming language: Fortran 77. Computer: Standard PC. Operating system: Windows. It might work with others. Successfully tested by CPC on Linux. RAM: For the test problems used less than 1 MB. Classification: 4.3, 4.12, 16.3, 17.17. Nature of problem: Some models in astronomy and astrophysics, quantum mechanics and nuclear physics lead to second-order oscillatory differential systems. The solution of these oscillatory models requires accurate and efficient numerical methods. The codes SVI-IIEXPOreferee.for and SVI-IIvarreferee.for were developed for this purpose. Solution method: We propose high-order exponentially fitted Runge-Kutta

  20. Analysis and application of high order implicit Runge-Kutta schemes for unsteady conjugate heat transfer: A strongly-coupled approach

    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.

  1. Embedded diagonally implicit Runge-Kutta algorithms on parallel computers

    NASA Astrophysics Data System (ADS)

    van der Houwen, P. J.; Sommeijer, B. P.; Couzy, W.

    1992-01-01

    This paper investigates diagonally implicit Runge-Kutta methods in which the implicit relations can be solved in parallel and are singly diagonal-implicit on each processor. The algorithms are based on diagonally implicit iteration of fully implicit Runge-Kutta methods of high order. The iteration scheme is chosen in such a way that the resulting algorithm is A(α ) -stable or L(α ) -stable with α equal or very close to π /2 . In this way, highly stable, singly diagonal-implicit Runge-Kutta methods of orders up to 10 can be constructed. Because of the iterative nature of the methods, embedded formulas of lower orders are automatically available, allowing a strategy for step and order variation.

  2. Galerkin/Runge-Kutta discretizations of nonlinear parabolic equations

    NASA Astrophysics Data System (ADS)

    Hansen, Eskil

    2007-08-01

    Global error bounds are derived for full Galerkin/Runge-Kutta discretizations of nonlinear parabolic problems, including the evolution governed by the p-Laplacian with p[greater-or-equal, slanted]2. The analysis presented here is not based on linearization procedures, but on the fully nonlinear framework of logarithmic Lipschitz constants and an extended B-convergence theory. The global error is bounded in L2 by [Delta]xr/2+[Delta]tq, where r is the convergence order of the Galerkin method applied to the underlying stationary problem and q is the stiff order of the algebraically stable Runge-Kutta method.

  3. Trigonometrical fitting conditions for two derivative Runge Kutta methods

    NASA Astrophysics Data System (ADS)

    Monovasilis, Th.; Kalogiratou, Z.; Simos, T. E.

    2016-12-01

    Trigonometrically fitted two derivative explicit Runge-Kutta methods are considered in this work. We give order conditions for trigonometrically fitted methods that use several evaluations of the f and the g functions. We present modified methods based on methods with several f evaluations and one g evaluation.

  4. 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.

  5. 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.

  6. Optimal Runge-Kutta schemes for discontinuous Galerkin space discretizations applied to wave propagation problems

    NASA Astrophysics Data System (ADS)

    Toulorge, T.; Desmet, W.

    2012-02-01

    We study the performance of methods of lines combining discontinuous Galerkin spatial discretizations and explicit Runge-Kutta time integrators, with the aim of deriving optimal Runge-Kutta schemes for wave propagation applications. We review relevant Runge-Kutta methods from literature, and consider schemes of order q from 3 to 4, and number of stages up to q + 4, for optimization. From a user point of view, the problem of the computational efficiency involves the choice of the best combination of mesh and numerical method; two scenarios are defined. In the first one, the element size is totally free, and a 8-stage, fourth-order Runge-Kutta scheme is found to minimize a cost measure depending on both accuracy and stability. In the second one, the elements are assumed to be constrained to such a small size by geometrical features of the computational domain, that accuracy is disregarded. We then derive one 7-stage, third-order scheme and one 8-stage, fourth-order scheme that maximize the stability limit. The performance of the three new schemes is thoroughly analyzed, and the benefits are illustrated with two examples. For each of these Runge-Kutta methods, we provide the coefficients for a 2 N-storage implementation, along with the information needed by the user to employ them optimally.

  7. 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.

  8. 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.

  9. 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.

  10. Stage-parallel fully implicit Runge-Kutta solvers for discontinuous Galerkin fluid simulations

    NASA Astrophysics Data System (ADS)

    Pazner, Will; Persson, Per-Olof

    2017-04-01

    In this paper, we develop new techniques for solving the large, coupled linear systems that arise from fully implicit Runge-Kutta methods. This method makes use of the iterative preconditioned GMRES algorithm for solving the linear systems, which has seen success for fluid flow problems and discontinuous Galerkin discretizations. By transforming the resulting linear system of equations, one can obtain a method which is much less computationally expensive than the untransformed formulation, and which compares competitively with other time-integration schemes, such as diagonally implicit Runge-Kutta (DIRK) methods. We develop and test several ILU-based preconditioners effective for these large systems. We additionally employ a parallel-in-time strategy to compute the Runge-Kutta stages simultaneously. Numerical experiments are performed on the Navier-Stokes equations using Euler vortex and 2D and 3D NACA airfoil test cases in serial and in parallel settings. The fully implicit Radau IIA Runge-Kutta methods compare favorably with equal-order DIRK methods in terms of accuracy, number of GMRES iterations, number of matrix-vector multiplications, and wall-clock time, for a wide range of time steps.

  11. 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.

  12. Some self starting integrators for x Prime equals f (x, t). [Runge-Kutta method and orbital position estimation

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1974-01-01

    The integration is discussed of the vector differential equation X = F(x, t) from time t sub i to t sub (i = 1) where only the values of x sub i are available for the the integration. No previous values of x or x prime are used. Using an orbit integration problem, comparisons are made between Taylor series integrators and various types and orders of Runge-Kutta integrators. A fourth order Runge-Kutta type integrator for orbital work is presented, and approximate (there may be no exact) fifth order Runge-Kutta integrators are discussed. Also discussed and compared is a self starting integrator ising delta f/delta x. A numerical method for controlling the accuracy of integration is given, and the special equations for accurately integrating accelerometer data are shown.

  13. 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.

  14. Stiffly accurate Runge-Kutta methods for nonlinear evolution problems governed by a monotone operator

    NASA Astrophysics Data System (ADS)

    Emmrich, Etienne; Thalhammer, Mechthild

    2010-04-01

    Stiffly accurate implicit Runge-Kutta methods are studied for the time discretisation of nonlinear first-order evolution equations. The equation is supposed to be governed by a time-dependent hemicontinuous operator that is (up to a shift) monotone and coercive, and fulfills a certain growth condition. It is proven that the piecewise constant as well as the piecewise linear interpolant of the time-discrete solution converges towards the exact weak solution, provided the Runge-Kutta method is consistent and satisfies a stability criterion that implies algebraic stability; examples are the Radau IIA and Lobatto IIIC methods. The convergence analysis is also extended to problems involving a strongly continuous perturbation of the monotone main part.

  15. Energy-conserving Runge-Kutta methods for the incompressible Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Sanderse, B.

    2013-01-01

    Energy-conserving methods have recently gained popularity for the spatial discretization of the incompressible Navier-Stokes equations. In this paper implicit Runge-Kutta methods are investigated which keep this property when integrating in time. Firstly, a number of energy-conserving Runge-Kutta methods based on Gauss, Radau and Lobatto quadrature are constructed. These methods are suitable for convection-dominated problems (such as turbulent flows), because they do not introduce artificial diffusion and are stable for any time step. Secondly, to obtain robust time-integration methods that work also for stiff problems, the energy-conserving methods are extended to a new class of additive Runge-Kutta methods, which combine energy conservation with L-stability. In this class, the Radau IIA/B method has the best properties. Results for a number of test cases on two-stage methods indicate that for pure convection problems the additive Radau IIA/B method is competitive with the Gauss methods. However, for stiff problems, such as convection-dominated flows with thin boundary layers, both the higher order Gauss and Radau IIA/B method suffer from order reduction. Overall, the Gauss methods are the preferred method for energy-conserving time integration of the incompressible Navier-Stokes equations.

  16. A generalization of the Runge-Kutta iteration

    NASA Astrophysics Data System (ADS)

    Haelterman, R.; Vierendeels, J.; van Heule, D.

    2009-02-01

    Iterative solvers in combination with multi-grid have been used extensively to solve large algebraic systems. One of the best known is the Runge-Kutta iteration. We show that a generally used formulation [A. Jameson, Numerical solution of the Euler equations for compressible inviscid fluids, in: F. Angrand, A. Dervieux, J.A. Désidéri, R. Glowinski (Eds.), Numerical Methods for the Euler Equations of Fluid Dynamics, SIAM, Philadelphia, 1985, pp. 199-245] does not allow to form all possible polynomial transmittance functions and we propose a new formulation to remedy this, without using an excessive number of coefficients. After having converted the optimal parameters found in previous studies (e.g. [B. Van Leer, C.H. Tai, K.G. Powell, Design of optimally smoothing multi-stage schemes for the Euler equations, AIAA Paper 89-1923, 1989]) we compare them with those that we obtain when we optimize for an integrated 2-grid V-cycle and show that this results in superior performance using a low number of stages. We also propose a variant of our new formulation that roughly follows the idea of the Martinelli-Jameson scheme [A. Jameson, Analysis and design of numerical schemes for gas dynamics 1, artificial diffusion, upwind biasing, limiter and their effect on multigrid convergence, Int. J. Comput. Fluid Dyn. 4 (1995) 171-218; J.V. Lassaline, Optimal multistage relaxation coefficients for multigrid flow solvers. http://www.ryerson.ca/~jvl/papers/cfd2005.pdf] used on the advection-diffusion equation which that can be extended to other types. Gains in the order of 30%-50% have been shown with respect to classical iterative schemes on the advection equation. Better results were also obtained on the advection-diffusion equation than with the Martinelli-Jameson coefficients, but with less than half the number of matrix-vector multiplications.

  17. Explicit Runge-Kutta schemes for incompressible flow with improved energy-conservation properties

    NASA Astrophysics Data System (ADS)

    Capuano, F.; Coppola, G.; Rández, L.; de Luca, L.

    2017-01-01

    The application of pseudo-symplectic Runge-Kutta methods to the incompressible Navier-Stokes equations is discussed in this work. In contrast to fully energy-conserving, implicit methods, these are explicit schemes of order p that preserve kinetic energy to order q, with q > p. Use of explicit methods with improved energy-conservation properties is appealing for convection-dominated problems, especially in case of direct and large-eddy simulation of turbulent flows. A number of pseudo-symplectic methods are constructed for application to the incompressible Navier-Stokes equations and compared in terms of accuracy and efficiency by means of numerical simulations.

  18. a New Methodology for the Construction of Optimized RUNGE-KUTTA-NYSTRÖM Methods

    NASA Astrophysics Data System (ADS)

    Papadopoulos, D. F.; Simos, T. E.

    In this paper, a new Runge-Kutta-Nyström method of fourth algebraic order is developed. The new method has zero phase-lag, zero amplification error and zero first integrals of the previous properties. Numerical results indicate that the new method is very efficient for solving numerically the Schrödinger equation. We note that for the first time in the literature we use the requirement of vanishing the first integrals of phase-lag and amplification error in the construction of efficient methods for the numerical solution of the Schrödinger equation.

  19. Parametric symplectic partitioned Runge-Kutta methods with energy-preserving properties for Hamiltonian systems

    NASA Astrophysics Data System (ADS)

    Wang, Dongling; Xiao, Aiguo; Li, Xueyang

    2013-02-01

    Based on W-transformation, some parametric symplectic partitioned Runge-Kutta (PRK) methods depending on a real parameter α are developed. For α=0, the corresponding methods become the usual PRK methods, including Radau IA-IA¯ and Lobatto IIIA-IIIB methods as examples. For any α≠0, the corresponding methods are symplectic and there exists a value α∗ such that energy is preserved in the numerical solution at each step. The existence of the parameter and the order of the numerical methods are discussed. Some numerical examples are presented to illustrate these results.

  20. Some Optimal Runge-Kutta Collocation Methods for Stiff Problems and DAEs

    NASA Astrophysics Data System (ADS)

    Gonzalez-Pinto, S.; Hernández-Abreu, D.; Montijano, J. I.

    2008-09-01

    A new family of implicit Runge-Kutta methods was introduced at ICCAM 2008 (Gent) by the present authors. This family of methods is intended to solve numerically stiff problems and DAEs. The s-stage method (for s⩾3) has the following features: it is a collocation method depending on a real free parameter β, has classical convergence order 2s-3 and is strongly A-stable for β ranging in some nonempty open interval Is = (-γs,0). In addition, for β∈Is, all the collocation nodes fall in the interval [0,1]. Moreover, these methods also involve a similar computational cost as that of the corresponding counterpart in the Runge-Kutta Radau IIA family (the method having the same classical order) when solving for their stage values. However, our methods have the additional advantage of possessing a higher stage order than the respective Radau IIA counterparts. This circumstance is important when integrating stiff problems in which case most of numerical methods are affected by an order reduction. In this talk we discuss how to optimize the free parameter depending on the special features of the kind of stiff problems and DAEs to be solved. This point is highly important in order to make competitive our methods when compared with those of the Radau IIA family.

  1. Runge-Kutta collocation methods for differential-algebraic equations of indices 2 and 3

    NASA Astrophysics Data System (ADS)

    Skvortsov, L. M.

    2012-10-01

    Stiffly accurate Runge-Kutta collocation methods with explicit first stage are examined. The parameters of these methods are chosen so as to minimize the errors in the solutions to differential-algebraic equations of indices 2 and 3. This construction results in methods for solving such equations that are superior to the available Runge-Kutta methods.

  2. 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.

  3. Global error estimation based on the tolerance proportionality for some adaptive Runge-Kutta codes

    NASA Astrophysics Data System (ADS)

    Calvo, M.; González-Pinto, S.; Montijano, J. I.

    2008-09-01

    the code Gauss2 [S. Gonzalez-Pinto, R. Rojas-Bello, Gauss2, a Fortran 90 code for second order initial value problems, ], based on an adaptive two stage Runge-Kutta-Gauss method with this discontinuous step-size policy.

  4. Rosenbrock methods in biogeochemical modelling - A comparison to Runge-Kutta methods and modified Patankar schemes

    NASA Astrophysics Data System (ADS)

    Schippmann, Bianca; Burchard, Hans

    Modelling biogeochemical processes in the surface ocean is still a difficult task due to the challenge to identify the most convenient integration scheme for the reaction terms. The scheme is expected to deal with the model characteristics of positivity and conservativity as well as with the different time scales involved, which occur e.g., whenever photochemical reactions take place in the water column. This paper presents a numerical comparison of the Rosenbrock methods, ROS3 and ROS4, often used for solving chemical reactions, to the explicit fourth-order Runge-Kutta method and the unconditionally positive modified Patankar schemes. Following their successful application in air chemistry, we here test the hypothesis that the Rosenbrock methods are an optimal choice for marine biogeochemical modelling in terms of efficiency and accuracy. In this study the schemes are compared in terms of runtime and accuracy and are applied to two test cases of different complexity: a zero-dimensional nutrient-phytoplankton-detritus (NPD)-type model and a one-dimensional nutrient-phytoplankton-zooplankton-detritus (NPZD)-type model. Applying the Rosenbrock methods to the simple NPD model shows their advantage over the other applied methods. They give the most accurate results of all solvers, especially for large step sizes, in less computing time due to their semi-implicitness and adaptive step sizing. On the contrary, for the one-dimensional NPZD model problem this is only the case in comparison to the Runge-Kutta solver, while their performance is worse than that of the second-order modified Patankar scheme. They need longer runtimes than the latter ones in order to achieve similarly accurate results. However, the modified Patankar schemes are not conservative if the system reactions contain more than one source compound. Thus, for more complex marine biogeochemical problems, it is recommended to apply the Rosenbrock methods while for simpler models the use of the second-order

  5. GPU acceleration of Runge Kutta-Fehlberg and its comparison with Dormand-Prince method

    NASA Astrophysics Data System (ADS)

    Seen, Wo Mei; Gobithaasan, R. U.; Miura, Kenjiro T.

    2014-07-01

    There is a significant reduction of processing time and speedup of performance in computer graphics with the emergence of Graphic Processing Units (GPUs). GPUs have been developed to surpass Central Processing Unit (CPU) in terms of performance and processing speed. This evolution has opened up a new area in computing and researches where highly parallel GPU has been used for non-graphical algorithms. Physical or phenomenal simulations and modelling can be accelerated through General Purpose Graphic Processing Units (GPGPU) and Compute Unified Device Architecture (CUDA) implementations. These phenomena can be represented with mathematical models in the form of Ordinary Differential Equations (ODEs) which encompasses the gist of change rate between independent and dependent variables. ODEs are numerically integrated over time in order to simulate these behaviours. The classical Runge-Kutta (RK) scheme is the common method used to numerically solve ODEs. The Runge Kutta Fehlberg (RKF) scheme has been specially developed to provide an estimate of the principal local truncation error at each step, known as embedding estimate technique. This paper delves into the implementation of RKF scheme for GPU devices and compares its result with Dorman Prince method. A pseudo code is developed to show the implementation in detail. Hence, practitioners will be able to understand the data allocation in GPU, formation of RKF kernels and the flow of data to/from GPU-CPU upon RKF kernel evaluation. The pseudo code is then written in C Language and two ODE models are executed to show the achievable speedup as compared to CPU implementation. The accuracy and efficiency of the proposed implementation method is discussed in the final section of this paper.

  6. Discovery and Optimization of Low-Storage Runge-Kutta Methods

    DTIC Science & Technology

    2015-06-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS DISCOVERY AND OPTIMIZATION OF LOW-STORAGE RUNGE-KUTTA METHODS by Matthew T. Fletcher June 2015... DISCOVERY AND OPTIMIZATION OF LOW-STORAGE RUNGE-KUTTA METH- ODS 5. FUNDING NUMBERS 6. AUTHOR(S) Matthew T. Fletcher 7. PERFORMING ORGANIZATION NAME(S...239–18 i THIS PAGE INTENTIONALLY LEFT BLANK ii Approved for public release; distribution is unlimited DISCOVERY AND OPTIMIZATION OF LOW-STORAGE RUNGE

  7. Full Discretisations for Nonlinear Evolutionary Inequalities Based on Stiffly Accurate Runge-Kutta and hp-Finite Element Methods.

    PubMed

    Gwinner, J; Thalhammer, M

    The convergence of full discretisations by implicit Runge-Kutta and nonconforming Galerkin methods applied to nonlinear evolutionary inequalities is studied. The scope of applications includes differential inclusions governed by a nonlinear operator that is monotone and fulfills a certain growth condition. A basic assumption on the considered class of stiffly accurate Runge-Kutta time discretisations is a stability criterion which is in particular satisfied by the Radau IIA and Lobatto IIIC methods. In order to allow nonconforming hp-finite element approximations of unilateral constraints, set convergence of convex subsets in the sense of Glowinski-Mosco-Stummel is utilised. An appropriate formulation of the fully discrete variational inequality is deduced on the basis of a characteristic example of use, a Signorini-type initial-boundary value problem. Under hypotheses close to the existence theory of nonlinear first-order evolutionary equations and inequalities involving a monotone main part, a convergence result for the piecewise constant in time interpolant is established.

  8. Exponential Runge-Kutta integrators for modelling Predator-Prey interactions

    NASA Astrophysics Data System (ADS)

    Diele, F.; Marangi, C.; Ragni, S.

    2012-09-01

    Spatially explicit models consisting of reaction-diffusion partial differential equations are considered in order to model prey-predator interactions, since it is known that the role of spatial processes reveals of great interest in the study of the effects of habitat fragmentation on biodiversity. As almost all of the realistic models in biology, these models are nonlinear and their solution is not known in closed form. Our aim is approximating the solution itself by means of exponential Runge-Kutta integrators. Moreover, we apply the shift-and-invert Krylov approach in order to evaluate the entire functions needed for implementing the exponential method. This numerical procedure reveals to be very eff cient in avoiding numerical instability during the simulation, since it allows us to adopt high order in the accuracy. This work has received funding from the European Union's Seventh Framework Programme FP7/2007-2013, SPA.2010.1.1-04: "Stimulating the development of GMES services in specif c are", under grant agreement 263435, project title: Biodiversity Multi-Source Monitoring System:from Space To Species (BIOSOS) coordinated by CNR-ISSIA, Bari-Italy (http://www.biosos.eu).

  9. 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.

  10. 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.

  11. Low-storage implicit/explicit Runge-Kutta schemes for the simulation of stiff high-dimensional ODE systems

    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.

  12. The design and applications of Runge-Kutta methods for the simulation of planetary orbits

    NASA Astrophysics Data System (ADS)

    Rabbi, S. M. Fajlay

    Since the merger of physics and mathematics at the beginning of 1800s, system of finding solution to n-body problem has been intriguing mathematicians. The resulting differential equations can be solved by a variety of approaches -- for example, the Runge-Kutta Methods (RKn). In this thesis, after a brief historical overview of planetary science, RK3 methods are derived as a three-parameter family of solution methods. A particular instance of this family, FR3, is generated and subsequently tested to show it is indeed a third-order method. The planetary system is modeled as a system of differential of equations using laws of classical mechanics, and the models of planetary motions are generated applying RK4 methods. Kepler's laws of planetary motion are proved empirically using observed data taken from NASA. A new way of expressing Kepler's third law is presented: the orbital velocity of a planet decreases as inverse square root of its orbital radius. Simulation of Sun-Earth-Moon as well as solar system is conducted and compared to that of Dahir's and found is a very similar result. Also, the result of the entire solar system simulation closely matches to that of NASA. Initial position-velocity vectors are generated from NASA-JPL's ephemeris data using post-processing codes obtained from the University of Colorado.

  13. Solutions of differential equations with regular coefficients by the methods of Richmond and Runge-Kutta

    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.

  14. Agglomeration multigrid methods with implicit Runge-Kutta smoothers applied to aerodynamic simulations on unstructured grids

    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.

  15. A Runge-Kutta discontinuous Galerkin approach to solve reactive flows: The hyperbolic operator

    SciTech Connect

    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.

  16. Embedded symmetric nested implicit Runge-Kutta methods of Gauss and Lobatto types for solving stiff ordinary differential equations and Hamiltonian systems

    NASA Astrophysics Data System (ADS)

    Kulikov, G. Yu.

    2015-06-01

    A technique for constructing nested implicit Runge-Kutta methods in the class of mono-implicit formulas of this type is studied. These formulas are highly efficient in practice, since the dimension of the original system of differential equations is preserved, which is not possible in the case of implicit multistage Runge-Kutta formulas of the general from. On the other hand, nested implicit Runge-Kutta methods inherit all major properties of general formulas of this form, such as A-stability, symmetry, and symplecticity in a certain sense. Moreover, they can have sufficiently high stage and classical orders and, without requiring high extra costs, can ensure dense output of integration results of the same accuracy as the order of the underlying method. Thus, nested methods are efficient when applied to the numerical integration of differential equations of various sorts, including stiff and nonstiff problems, Hamiltonian systems, and invertible equations. In this paper, previously proposed nested methods based on the Gauss quadrature formulas are generalized to Lobatto-type methods. Additionally, a unified technique for constructing all such methods is proposed. Its performance is demonstrated as applied to embedded examples of nested implicit formulas of various orders. All the methods constructed are supplied with tools for local error estimation and automatic variable-stepsize mesh generation based on an optimal stepsize selection. These numerical methods are verified by solving test problems with known solutions. Additionally, a comparative analysis of these methods with Matlab built-in solvers is presented.

  17. 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.

  18. Thermal engineering research. [Runge-Kutta investigation of gas flow inside multilayer insulation system for rocket booster fuel tanks

    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.

  19. Parallel Implicit Runge-Kutta Methods Applied to Coupled Orbit/Attitude Propagation

    NASA Astrophysics Data System (ADS)

    Hatten, Noble; Russell, Ryan P.

    2016-12-01

    A variable-step Gauss-Legendre implicit Runge-Kutta (GLIRK) propagator is applied to coupled orbit/attitude propagation. Concepts previously shown to improve efficiency in 3DOF propagation are modified and extended to the 6DOF problem, including the use of variable-fidelity dynamics models. The impact of computing the stage dynamics of a single step in parallel is examined using up to 23 threads and 22 associated GLIRK stages; one thread is reserved for an extra dynamics function evaluation used in the estimation of the local truncation error. Efficiency is found to peak for typical examples when using approximately 8 to 12 stages for both serial and parallel implementations. Accuracy and efficiency compare favorably to explicit Runge-Kutta and linear-multistep solvers for representative scenarios. However, linear-multistep methods are found to be more efficient for some applications, particularly in a serial computing environment, or when parallelism can be applied across multiple trajectories.

  20. Efficient low-storage Runge-Kutta schemes with optimized stability regions

    NASA Astrophysics Data System (ADS)

    Niegemann, Jens; Diehl, Richard; Busch, Kurt

    2012-01-01

    A variety of numerical calculations, especially when considering wave propagation, are based on the method-of-lines, where time-dependent partial differential equations (PDEs) are first discretized in space. For the remaining time-integration, low-storage Runge-Kutta schemes are particularly popular due to their efficiency and their reduced memory requirements. In this work, we present a numerical approach to generate new low-storage Runge-Kutta (LSRK) schemes with optimized stability regions for advection-dominated problems. Adapted to the spectral shape of a given physical problem, those methods are found to yield significant performance improvements over previously known LSRK schemes. As a concrete example, we present time-domain calculations of Maxwell's equations in fully three-dimensional systems, discretized by a discontinuous Galerkin approach.

  1. Active and passive symmetrization of Runge-Kutta Lobatto IIIA methods

    NASA Astrophysics Data System (ADS)

    Gorgey, A.; Chan, R. P. K.

    2012-09-01

    Symmetrization of the Runge-Kutta Gauss methods have been shown to be robust in solving stiff linear and nonlinear initial value ordinary differential equations [4]. The most efficient way of applying symmmetrization was found to be passive symmetrization with passive extrapolation. In this paper we investigate symmetrization of the Lobatto IIIA methods. We show numerically that the same strategy of using passive symmetrization applied with passive extrapolation of the Lobbatto IIIA methods is also most efficient in solving the nonlinear problems tested.

  2. H[alpha]-stability of modified Runge-Kutta methods for nonlinear neutral pantograph equations

    NASA Astrophysics Data System (ADS)

    Ma, S. F.; Yang, Z. W.; Liu, M. Z.

    2007-11-01

    In this paper, we investigate H[alpha]-stability of algebraically stable Runge-Kutta methods with a variable stepsize for nonlinear neutral pantograph equations. As a result, the Radau IA, Radau IIA, Lobatto IIIC method, the odd-stage Gauss-Legendre methods and the one-leg [theta]-method with are H[alpha]-stable for nonlinear neutral pantograph equations. Some experiments are given.

  3. 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

  4. An unconditionally stable Runge-Kutta method for unsteady rotor-stator interaction

    NASA Technical Reports Server (NTRS)

    Chima, Rodrick V.; Jorgenson, Philip C. E.

    1989-01-01

    A quasi-three-dimensional analysis has been developed for unsteady rotor-stator interaction 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 stress-surface thickness. The Baldwin-Lomax eddy-viscosity model is used for turbulent flows. The equations are integrated in time using an explicit four-stage Runge-Kutta scheme with a constant time step. Implicit residual smoothing is used to increase the stability limit of the time-accurate computations. The scheme is described, and stability and accuracy analyses are given.

  5. Runge-Kutta ray tracing technique for solving radiative heat transfer in a two-dimensional graded-index medium

    NASA Astrophysics Data System (ADS)

    Huang, Yong; Shi, Guo-Dong; Zhu, Ke-Yong

    2016-06-01

    This paper adopts the Runge-Kutta ray tracing method to obtain the ray-trajectory numerical solution in a two-dimensional gradient index medium. The emitting, absorbing and scattering processes are simulated by the Monte Carlo method. The temperature field and ray trajectory in the medium are obtained by the three methods, the Runge-Kutta ray tracing method, the ray tracing method with the cell model and the discrete curved ray tracing method with the linear refractive index cell model. Comparing the results of the three methods, it is found that the results by the Monte Carlo Runge-Kutta ray tracing method are of the highest accuracy. To improve the computational speed, the variable step-size Runge-Kutta ray tracing method is proposed, and the maximum relative error between the temperature field in the nonscattering medium by this method and the benchmark solution is less than 0.5%. The results also suggest that the Runge-Kutta ray tracing method would make the radiative transfer solution in the three-dimensional graded index media much easier.

  6. 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.

  7. Improving the accuracy of simulation of radiation-reaction effects with implicit Runge-Kutta-Nyström methods.

    PubMed

    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.

  8. 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.

  9. Convergence acceleration of rational Runge-Kutta scheme for Euler and Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Morinishi, Koji; Nobuyuki, Satofuka

    Modifications introduced to improve the performance of the rational-Runge-Kutta Euler/Navier-Stokes solver of Morishini and Satofuka (1987 and 1988) are discussed, summarizing the results of recent investigations. The derivation of the governing equations and the basic numerical procedure are outlined, and the use of the residual-averaging technique and multigrid methods to accelerate convergence is explained. Results are presented in graphs for (1) two-dimensional inviscid flow on a NACA 0012 airfoil at Mach 0.8 and angle of attack alpha = 1.25 deg, (2) two-dimensional viscous flow on an RAE 2822 airfoil at Mach 0.73 and alpha = 2.80 deg, and (3) three-dimensional inviscid flow on the ONERA M6 wing at Mach 0.84 and alpha = 3.06 deg. The steady-state convergence of the method is shown to be comparable to that of diagonalized implicit approximate-factorization schemes.

  10. A stabilized Runge-Kutta-Legendre method for explicit super-time-stepping of parabolic and mixed equations

    NASA Astrophysics Data System (ADS)

    Meyer, Chad D.; Balsara, Dinshaw S.; Aslam, Tariq D.

    2014-01-01

    Parabolic partial differential equations appear in several physical problems, including problems that have a dominant hyperbolic part coupled to a sub-dominant parabolic component. Explicit methods for their solution are easy to implement but have very restrictive time step constraints. Implicit solution methods can be unconditionally stable but have the disadvantage of being computationally costly or difficult to implement. Super-time-stepping methods for treating parabolic terms in mixed type partial differential equations occupy an intermediate position. In such methods each superstep takes “s” explicit Runge-Kutta-like time-steps to advance the parabolic terms by a time-step that is s2 times larger than a single explicit time-step. The expanded stability is usually obtained by mapping the short recursion relation of the explicit Runge-Kutta scheme to the recursion relation of some well-known, stable polynomial. Prior work has built temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Chebyshev polynomials. Since their stability is based on the boundedness of the Chebyshev polynomials, these methods have been called RKC1 and RKC2. In this work we build temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Legendre polynomials. We call these methods RKL1 and RKL2. The RKL1 method is first-order accurate in time; the RKL2 method is second-order accurate in time. We verify that the newly-designed RKL1 and RKL2 schemes have a very desirable monotonicity preserving property for one-dimensional problems - a solution that is monotone at the beginning of a time step retains that property at the end of that time step. It is shown that RKL1 and RKL2 methods are stable for all values of the diffusion coefficient up to the maximum value. We call this a convex monotonicity preserving property and show by examples that it is very useful in

  11. Runge-Kutta central discontinuous Galerkin BGK method for the Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Ren, Tan; Hu, Jun; Xiong, Tao; Qiu, Jing-Mei

    2014-10-01

    In this paper, we propose a Runge-Kutta (RK) central discontinuous Galerkin (CDG) gas-kinetic BGK method for the Navier-Stokes equations. The proposed method is based on the CDG method defined on two sets of overlapping meshes to avoid discontinuous solutions at cell interfaces, as well as the gas-kinetic BGK model to evaluate fluxes for both convection and diffusion terms. Redundant representation of the numerical solution in the CDG method offers great convenience in the design of gas-kinetic BGK fluxes. Specifically, the evaluation of fluxes at cell interfaces of one set of computational mesh is right inside the cells of the staggered mesh, hence the corresponding particle distribution function for flux evaluation is much simpler than that in existing gas-kinetic BGK methods. As a central scheme, the proposed CDG-BGK has doubled the memory requirement as the corresponding DG scheme; on the other hand, for the convection part, the CFL time step constraint of the CDG method for numerical stability is relatively large compared with that for the DG method. Numerical boundary conditions have to be treated with special care. Numerical examples for 1D and 2D viscous flow simulations are presented to validate the accuracy and robustness of the proposed RK CDG-BGK method.

  12. Overcoming Geometry-Induced Stiffness with IMplicit-Explicit (IMEX) Runge-Kutta Algorithms on Unstructured Grids with Applications to CEM, CFD, and CAA

    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.

  13. A Runge-Kutta, Taylor-Galerkin scheme for hyperbolic systems with source terms. Application to shock wave propagation in viscoplastic geomaterials

    NASA Astrophysics Data System (ADS)

    Mabssout, M.; Pastor, M.; Herreros, M. I.; Quecedo, M.

    2006-11-01

    This paper presents an alternative formulation of Solid Dynamics problems based on (i) a mathematical model consisting of a system of hyperbolic PDEs where the source term is originated by the viscoplastic strain rate and (ii) a splitting scheme where the two-step Taylor-Galerkin is used for the advective part of the PDE operator while the sources are integrated using a fourth-order Runge-Kutta. Use of the splitting scheme results in a higher accuracy than that of the original two-step Taylor-Galerkin. The scheme performs well when used with linear triangle or tetrahedra for (i) bending-dominated situations (ii) localized failure under dynamic conditions and keeps the advantages of the two-step Taylor-Galerkin concerning numerical dispersion and damping of short wavelengths. Copyright

  14. High-Order Methods For Wave Propagation

    DTIC Science & Technology

    2008-01-01

    typically combined with high-order explicit time-integration methods such as the multi-stage Runge - Kutta procedure. In addition to the spatial and temporal... methods include both an explicit Runge - Kutta fourth- order temporally accurate scheme as well as an implicit, approximately factored Beam-Warming scheme of...12]. 3.2.3 Time Integration The equations are integrated in time with the classical fourth-order four-stage Runge - Kutta method . With R denoting the

  15. The theoretical accuracy of Runge-Kutta time discretizations for the initial boundary value problem: A careful study of the boundary error

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Gottlieb, David; Abarbanel, Saul; Don, Wai-Sun

    1993-01-01

    The conventional method of imposing time dependent boundary conditions for Runge-Kutta (RK) time advancement reduces the formal accuracy of the space-time method to first order locally, and second order globally, independently of the spatial operator. This counter intuitive result is analyzed in this paper. Two methods of eliminating this problem are proposed for the linear constant coefficient case: (1) impose the exact boundary condition only at the end of the complete RK cycle, (2) impose consistent intermediate boundary conditions derived from the physical boundary condition and its derivatives. The first method, while retaining the RK accuracy in all cases, results in a scheme with much reduced CFL condition, rendering the RK scheme less attractive. The second method retains the same allowable time step as the periodic problem. However it is a general remedy only for the linear case. For non-linear hyperbolic equations the second method is effective only for for RK schemes of third order accuracy or less. Numerical studies are presented to verify the efficacy of each approach.

  16. 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.

  17. A New Runge-Kutta Discontinuous Galerkin Method with Conservation Constraint to Improve CFL Condition for Solving Conservation Laws

    PubMed Central

    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

  18. A New Runge-Kutta Discontinuous Galerkin Method with Conservation Constraint to Improve CFL Condition for Solving Conservation Laws.

    PubMed

    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.

  19. A phase-preserving and low-dispersive symplectic partitioned Runge-Kutta method for solving seismic wave equations

    NASA Astrophysics Data System (ADS)

    Ma, Xiao; Yang, Dinghui

    2017-03-01

    The finite-difference method, which is an important numerical tool for solving seismic wave equations, is widely applied in wavefield simulation, wave-equation-based migration and inversion. As the seismic wave phase plays a critical role in forward simulation and inversion, it should be preserved during wavefield simulation. In this paper, we propose a type of phase-preserving stereomodelling method, which is simultaneously symplectic and low numerical dispersive. First, we propose three new time-marching schemes for solving wave equations that are optimal symplectic partitioned Runge-Kutta schemes with minimized phase errors. Relevant simulations on a harmonic oscillator show that even after 200,000 temporal iterations, our schemes can still avoid the phase drifting issue that appears in other symplectic schemes. We use these symplectic schemes as time integrators, and a numerically low dispersive operator called the stereomodelling discrete operator as a spatial discretization approach to solve seismic wave equations. Theoretical analysis on the stability conditions shows that the new methods are more stable than previous methods. We also investigate the numerical dispersion relations of the methods proposed in this study. To further investigate phase accuracy, we compare the numerical solutions generated by the proposed methods with analytic solutions. Several numerical experiments indicate that our proposed methods are efficient for various models and perform well with perfectly matched layer boundary conditions.

  20. A symplectic Runge Kutta Nyström method with minimal phase-lag

    NASA Astrophysics Data System (ADS)

    van de Vyver, H.

    2007-07-01

    In this Letter we introduce a symplectic explicit RKN method for Hamiltonian systems with periodical solutions. The method has algebraic order three and phase-lag order six at a cost of three function evaluations per step. Numerical experiments show the relevance of the developed algorithm. It is found that the new method is much more efficient than the standard symplectic fourth-order method [M.P. Calvo, J.M. Sanz-Serna, SIAM J. Sci. Comput. 14 (1993) 936].

  1. Investigation of upwind, multigrid, multiblock numerical schemes for three dimensional flows. Volume 1: Runge-Kutta methods for a thin layer Navier-Stokes solver

    NASA Technical Reports Server (NTRS)

    Cannizzaro, Frank E.; Ash, Robert L.

    1992-01-01

    A state-of-the-art computer code has been developed that incorporates a modified Runge-Kutta time integration scheme, upwind numerical techniques, multigrid acceleration, and multi-block capabilities (RUMM). A three-dimensional thin-layer formulation of the Navier-Stokes equations is employed. For turbulent flow cases, the Baldwin-Lomax algebraic turbulence model is used. Two different upwind techniques are available: van Leer's flux-vector splitting and Roe's flux-difference splitting. Full approximation multi-grid plus implicit residual and corrector smoothing were implemented to enhance the rate of convergence. Multi-block capabilities were developed to provide geometric flexibility. This feature allows the developed computer code to accommodate any grid topology or grid configuration with multiple topologies. The results shown in this dissertation were chosen to validate the computer code and display its geometric flexibility, which is provided by the multi-block structure.

  2. 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.

  3. 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.

  4. Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

    DTIC Science & Technology

    2008-02-14

    implicit Runge - Kutta method is used for temporal integration, where the time step size is obtained based on CFL number and grid size. The steady base flow...five fundamental solutions (continuous spectrum). A fourth order Runge - Kutta integration method with constant step (301 points) was used to integrate...code had an auxiliary role, and it served for verification of the other code that was based on the 4th-order Runge - Kutta solver for equations (A.3) and

  5. Using a time-domain higher-order boundary element method to simulate wave and current diffraction from a 3-D body

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Teng, Bin; Ning, De-Zhi; Sun, Liang

    2010-06-01

    To study wave-current actions on 3-D bodies a time-domain numerical model was established using a higher-order boundary element method (HOBEM). By assuming small flow velocities, the velocity potential could be expressed for linear and higher order components by perturbation expansion. A 4th-order Runge-Kutta method was applied for time marching. An artificial damping layer was adopted at the outer zone of the free surface mesh to dissipate scattering waves. Validation of the numerical method was carried out on run-up, wave exciting forces, and mean drift forces for wave-currents acting on a bottom-mounted vertical cylinder. The results were in close agreement with the results of a frequency-domain method and a published time-domain method. The model was then applied to compute wave-current forces and run-up on a Seastar mini tension-leg platform.

  6. A 4th-order reconfigurable analog baseband filter for software-defined radio applications

    NASA Astrophysics Data System (ADS)

    Weiwei, Wang; Xuegui, Chang; Xiao, Wang; Kefeng, Han; Xi, Tan; Na, Yan; Hao, Min

    2011-04-01

    This paper presents a 4th-order reconfigurable analog baseband filter for software-defined radios. The design exploits an active-RC low pass filter (LPF) structure with digital assistant, which is flexible for tunability of filter characteristics, such as cut-off frequency, selectivity, type, noise, gain and power. A novel reconfigurable operational amplifier is proposed to realize the optimization of noise and scalability of power dissipation. The chip was fabricated in an SMIC 0.13 μm CMOS process. The main filter and frequency calibration circuit occupy 1.8 × 0.8 mm2 and 0.48 × 0.25 mm2 areas, respectively. The measurement results indicate that the filter provides Butterworth and Chebyshev responses with a wide frequency tuning range from 280 kHz to 15 MHz and a gain range from 0 to 18 dB. An IIP3 of 29 dBm is achieved under a 1.2 V power supply. The input inferred noise density varies from 41 to 133 according to a given standard, and the power consumptions are 5.46 mW for low band (from 280 kHz to 3 MHz) and 8.74 mW for high band (from 3 to 15 MHz) mode.

  7. 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

    2017-01-01

    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.

  8. 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.

  9. 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.

  10. Spectral Large-Eddy Simulation/Filtered Mass Density Function (LES/FMDF) for Simulation of Turbulent Combustion Interaction in High Speed Flow on Unstructured Grids

    DTIC Science & Technology

    2011-10-01

    1 4 (28) The time stepping method used in this work is the low-storage, third-order, Runge - Kutta scheme presented by Williamson [6]. The...developing, reacting mixing layer, the governing equations are solved using 4th order spatial compact scheme with 3rd order Runge - Kutta method for time...solution away from the shock. Explicit (spectral) filtering is used to model the filtered small scales in LES. This method has a negligible

  11. 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.

  12. On positivity-preserving high order discontinuous Galerkin schemes for compressible Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangxiong

    2017-01-01

    We construct a local Lax-Friedrichs type positivity-preserving flux for compressible Navier-Stokes equations, which can be easily extended to multiple dimensions for generic forms of equations of state, shear stress tensor and heat flux. With this positivity-preserving flux, any finite volume type schemes including discontinuous Galerkin (DG) schemes with strong stability preserving Runge-Kutta time discretizations satisfy a weak positivity property. With a simple and efficient positivity-preserving limiter, high order explicit Runge-Kutta DG schemes are rendered preserving the positivity of density and internal energy without losing local conservation or high order accuracy. Numerical tests suggest that the positivity-preserving flux and the positivity-preserving limiter do not induce excessive artificial viscosity, and the high order positivity-preserving DG schemes without other limiters can produce satisfying non-oscillatory solutions when the nonlinear diffusion in compressible Navier-Stokes equations is accurately resolved.

  13. 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.

  14. High-order implicit time-marching methods for unsteady fluid flow simulation

    NASA Astrophysics Data System (ADS)

    Boom, Pieter David

    Unsteady computational fluid dynamics (CFD) is increasingly becoming a critical tool in the development of emerging technologies and modern aircraft. In spite of rapid mathematical and technological advancement, these simulations remain computationally intensive and time consuming. More efficient temporal integration will promote a wider use of unsteady analysis and extend its range of applicability. This thesis presents an investigation of efficient high-order implicit time-marching methods for application in unsteady compressible CFD. A generalisation of time-marching methods based on summation-by-parts (SBP) operators is described which reduces the number of stages required to obtain a prescribed order of accuracy, thus improving their efficiency. The classical accuracy and stability theory is formally extended for these generalised SBP (GSBP) methods, including superconvergence and nonlinear stability. Dual-consistent SBP and GSBP time-marching methods are shown to form a subclass of implicit Runge-Kutta methods, which enables extensions of nonlinear accuracy and stability results. A novel family of fully-implicit GSBP Runge-Kutta schemes based on Gauss quadrature are derived which are both algebraically stable and L-stable with order 2s - 1, where s is the number of stages. In addition, a numerical tool is developed for the construction and optimisation of general linear time-marching methods. The tool is applied to the development of several low-stage-order L-stable diagonally-implicit methods, including a diagonally-implicit GSBP Runge-Kutta scheme. The most notable and efficient method developed is a six-stage fifth-order L-stable stiffly-accurate explicit-first-stage singly-diagonally-implicit Runge-Kutta (ESDIRK5) method with stage order two. The theoretical results developed in this thesis are supported by numerical simulations, and the predicted relative efficiency of the schemes is realised.

  15. Learning about the Unfairgrounds: A 4th-Grade Teacher Introduces Her Students to Executive Order 9066

    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…

  16. High-order implicit residual smoothing time scheme for direct and large eddy simulations of compressible flows

    NASA Astrophysics Data System (ADS)

    Cinnella, P.; Content, C.

    2016-12-01

    Restrictions on the maximum allowable time step of explicit time integration methods for direct and large eddy simulations of compressible turbulent flows at high Reynolds numbers can be very severe, because of the extremely small space steps used close to solid walls to capture tiny and elongated boundary layer structures. A way of increasing stability limits is to use implicit time integration schemes. However, the price to pay is a higher computational cost per time step, higher discretization errors and lower parallel scalability. In quest for an implicit time scheme for scale-resolving simulations providing the best possible compromise between these opposite requirements, we develop a Runge-Kutta implicit residual smoothing (IRS) scheme of fourth-order accuracy, based on a bilaplacian operator. The implicit operator involves the inversion of scalar pentadiagonal systems, for which efficient parallel algorithms are available. The proposed method is assessed against two explicit and two implicit time integration techniques in terms of computational cost required to achieve a threshold level of accuracy. Precisely, the proposed time scheme is compared to four-stages and six-stages low-storage Runge-Kutta method, to the second-order IRS and to a second-order backward scheme solved by means of matrix-free quasi-exact Newton subiterations. Numerical results show that the proposed IRS scheme leads to reductions in computational time by a factor 3 to 5 for an accuracy comparable to that of the corresponding explicit Runge-Kutta scheme.

  17. Development of a low-noise, 4th-order readout ASIC for CdZnTe detectors in gamma spectrometer applications

    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.

  18. Computational modes and the Machenauer N.L.N.M.I. of the GLAS 4th order model. [NonLinear Normal Mode Initialization in numerical weather forecasting

    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.

  19. A 4th-order band-pass filter using differential readout of two in-phase actuated contour-mode resonators

    NASA Astrophysics Data System (ADS)

    Yagubizade, Hadi; Darvishi, Milad; Elwenspoek, Miko C.; Tas, Niels R.

    2013-10-01

    A 4th-order band-pass filter (BPF) based on the subtraction of two 2nd-order contour-mode Lamb-wave resonators is presented. The resonators have slightly different resonance frequencies around 380 MHz. Each resonator consists of a 500 nm pulsed-laser deposited lead zirconate titanate (PZT) thin-film on top of a 3 μm silicon (PZT-on-Si). The resonators are actuated in-phase, and their outputs are subtracted. Utilizing this technique, the feed-through signals are eliminated while the outputs of the resonators are added up constructively, due to the phase difference between the two output signals. The BPF is presented using 50 Ω termination with a bandwidth of approximately 3.9 MHz and 43 dB stopband rejection. This technique provides further opportunities for MEMS filter design in addition to existing methods, i.e., mechanical and/or electrical coupling. It also resolves the design issue associated with high feed-through when exploiting piezoelectric materials with high-dielectric constant like PZT.

  20. Radiation effects on stagnation point flow with melting heat transfer and second order slip

    NASA Astrophysics Data System (ADS)

    Mabood, F.; Shafiq, A.; Hayat, T.; Abelman, S.

    This article examines the effects of melting heat transfer and thermal radiation in stagnation point flow towards a stretching/shrinking surface. Mathematical formulation is made in the presence of mass transfer and second order slip condition. Numerical solutions to the resulting nonlinear problems are obtained by Runge-Kutta fourth fifth order method. Physical quantities like velocity, temperature, concentration, skin friction, Nusselt and Sherwood number are analyzed via sundry parameters for stretching/shrinking, first order slip, second order slip, radiation, melting, Prandtl and Schmidt. A comparative study with the previously published results in limiting sense is made.

  1. Nonlinear Dynamic Stability of the Viscoelastic Plate Considering Higher Order Modes

    NASA Astrophysics Data System (ADS)

    Sun, Yuanxiang; Wang, Cheng

    2016-11-01

    -The dynamic stability of viscoelastic plates is investigated in this paper by using chaotic and fractal theory. The nonlinear integro-differential dynamic equation is changed into an autonomic 4-dimensional dynamical system. The numerical time integrations of equations are obtained by using the fourth order Runge-Kutta method. And the Lyapunov exponent spectrum, the fractal dimension of strange attractors and the time evolution of deflection are obtained. The influence of viscoelastic parameter on dynamic buckling of viscoelastic plates is discussed. The effect of higher order modes on dynamic stability of viscoelastic plate is obtained, the necessity of considering higher order modes is discussed.

  2. Fourth order exponential time differencing method with local discontinuous Galerkin approximation for coupled nonlinear Schrodinger equations

    DOE PAGES

    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.

  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.

  4. 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

  5. An adaptive multiblock high-order finite-volume method for solving the shallow-water equations on the sphere

    DOE PAGES

    McCorquodale, Peter; Ullrich, Paul; Johansen, Hans; ...

    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.

  6. High order numerical methods for networks of hyperbolic conservation laws coupled with ODEs and lumped parameter models

    NASA Astrophysics Data System (ADS)

    Borsche, Raul; Kall, Jochen

    2016-12-01

    In this paper we construct high order finite volume schemes on networks of hyperbolic conservation laws with coupling conditions involving ODEs. We consider two generalized Riemann solvers at the junction, one of Toro-Castro type and a solver of Harten, Enquist, Osher, Chakravarthy type. The ODE is treated with a Taylor method or an explicit Runge-Kutta scheme, respectively. Both resulting high order methods conserve quantities exactly if the conservation is part of the coupling conditions. Furthermore we present a technique to incorporate lumped parameter models, which arise from simplifying parts of a network. The high order convergence and the robust capturing of shocks are investigated numerically in several test cases.

  7. Explicit high-order symplectic integrators for charged particles in general electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Tao, Molei

    2016-12-01

    This article considers non-relativistic charged particle dynamics in both static and non-static electromagnetic fields, which are governed by nonseparable, possibly time-dependent Hamiltonians. For the first time, explicit symplectic integrators of arbitrary high-orders are constructed for accurate and efficient simulations of such mechanical systems. Performances superior to the standard non-symplectic method of Runge-Kutta are demonstrated on two examples: the first is on the confined motion of a particle in a static toroidal magnetic field used in tokamak; the second is on how time-periodic perturbations to a magnetic field inject energy into a particle via parametric resonance at a specific frequency.

  8. A Freestream-Preserving High-Order Finite-Volume Method for Mapped Grids with Adaptive-Mesh Refinement

    SciTech Connect

    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.

  9. A high-order finite-volume method for hyperbolic conservation laws on locally-refined grids

    SciTech Connect

    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.

  10. The 4th Thermodynamic Principle?

    SciTech Connect

    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.

  11. Seismic Waves, 4th order accurate

    SciTech Connect

    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.

  12. Numerical solution of first order initial value problem using 7-stage tenth order Gauss-Kronrod-Lobatto IIIA method

    NASA Astrophysics Data System (ADS)

    Ying, Teh Yuan; Yaacob, Nazeeruddin

    2013-04-01

    In this paper, a new implicit Runge-Kutta method which based on a 7-point Gauss-Kronrod-Lobatto quadrature formula is developed. The resulting implicit method is a 7-stage tenth order Gauss-Kronrod-Lobatto IIIA method, or in brief as GKLM(7,10)-IIIA. GKLM(7,10)-IIIA requires seven function of evaluations at each integration step and it gives accuracy of order ten. In addition, GKLM(7,10)-IIIA has stage order seven and being A-stable. Numerical experiments compare the accuracy between GKLM(7,10)-IIIA and the classical 5-stage tenth order Gauss-Legendre method in solving some test problems. Numerical results reveal that GKLM(7,10)-IIIA is more accurate than the 5-stage tenth order Gauss-Legendre method because GKLM(7,10)-IIIA has higher stage order.

  13. Numerical solution of first order initial value problem using 4-stage sixth order Gauss-Kronrod-Radau IIA method

    NASA Astrophysics Data System (ADS)

    Ying, Teh Yuan; Yaacob, Nazeeruddin

    2013-04-01

    In this paper, a new implicit Runge-Kutta method which based on a 4-point Gauss-Kronrod-Radau II quadrature formula is developed. The resulting implicit method is a 4-stage sixth order Gauss-Kronrod-Radau IIA method, or in brief as GKRM(4,6)-IIA. GKRM(4,6)-IIA requires four function of evaluations at each integration step and it gives accuracy of order six. In addition, GKRM(4,6)-IIA has stage order four and being L-stable. Numerical experiments compare the accuracy between GKRM(4,6)-IIA and the classical 3-stage sixth order Gauss-Legendre method in solving some test problems. Numerical results reveal that GKRM(4,6)-IIA is more accurate than the 3-stage sixth order Gauss-Legendre method because GKRM(4,6)-IIA has higher stage order.

  14. Performance of Several High Order Numerical Methods for Supersonic Combustion

    NASA Technical Reports Server (NTRS)

    Sjoegreen, Bjoern; Yee, H. C.; Don, Wai Sun; Mansour, Nagi N. (Technical Monitor)

    2001-01-01

    The performance of two recently developed numerical methods by Yee et al. and Sjoegreen and Yee using postprocessing nonlinear filters is examined for a 2-D multiscale viscous supersonic react-live flow. These nonlinear filters can improve nonlinear instabilities and at the same time can capture shock/shear waves accurately. They do not, belong to the class of TVD, ENO or WENO schemes. Nevertheless, they combine stable behavior at discontinuities and detonation without smearing the smooth parts of the flow field. For the present study, we employ a fourth-order Runge-Kutta in time and a sixth-order non-dissipative spatial base scheme for the convection and viscous terms. We denote the resulting nonlinear filter schemes ACM466-RK4 and WAV66-RK4.

  15. Second-Order Accurate Projective Integrators for Multiscale Problems

    SciTech Connect

    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.

  16. Computational Fluid Dynamic Solutions of Optimized Heat Shields Designed for Earth Entry

    DTIC Science & Technology

    2010-01-01

    College Park Trajectory Optimization Program(UPTOP),23 which employs a 4th-order Runge - Kutta rou- tine to propagate the three-degrees-of-freedom point...support of whom is greatly appreciated. Special thanks must go to my coworkers in the hypersonics group (Neal Smith, Vijay Ramasubramanian, Adam Beerman...12 1.2.3.2 Radiation . . . . . . . . . . . . . . . . . . . . . . . . 13 1.2.4 Optimization Methods

  17. Construction and Analysis of Multi-Rate Partitioned Runge-Kutta Methods

    DTIC Science & Technology

    2012-06-01

    chapter, that the value of σ ( Courant number) will play an important role in determining where our numerical method is stable, as it measures how fast... method gradually incurred both dissipation and dispersion errors, it was still stable. However, for the same Courant value of 0.5, we notice that the...4245, F. X. Giraldo, Department of Applied Mathematics , Naval Postgraduate School, Spring 2012. [9] D. R. Durran, Numerical Methods for Wave

  18. Projected implicit Runge-Kutta methods for differential-algebraic boundary value problems

    SciTech Connect

    Ascher, U. ); Petzoid, L. )

    1990-09-01

    Differential-algebraic boundary value problems arise in the modelling of singular optimal control problems and in parameter estimation for singular systems. A new class of numerical methods for these problems is introduced, and shown to overcome difficulties with previously defined numerical methods. 4 refs., 1 tab.

  19. The Leap into 4th Grade

    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…

  20. 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.

  1. Direct calculations of waves in fluid flows using a high-order compact difference scheme

    NASA Technical Reports Server (NTRS)

    Yu, Sheng-Tao; Hultgren, Lennart S.; Liu, Nan-Suey

    1993-01-01

    The solution of the unsteady Euler equations by a sixth-order compact difference scheme combined with a fourth-order Runge-Kutta method is investigated. Closed-form expressions for the amplification factors and their corresponding dispersion correlations are obtained by Fourier analysis of the fully discretized, two-dimensional Euler equations, and the numerical dissipation, dispersion, and anisotropic effects are assessed. It is found that the CFL limit for stable calculations is about 0.8. For a CFL number equal to 0.6, the smallest wavelength which is resolved without numerical damping is about 6 to 8 grid nodes. For phase speeds corresponding to acoustic waves, the corresponding time period is resolved by about 200 to 300 time steps. Three numerical examples of waves in compressible flow are included.

  2. Third-order-accurate numerical methods for efficient, large time-step solutions of mixed linear and nonlinear problems

    SciTech Connect

    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.

  3. High-order compact MacCormack scheme for two-dimensional compressible and non-hydrostatic equations of the atmosphere

    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.

  4. High-order weighted essentially nonoscillatory finite-difference formulation of the lattice Boltzmann method in generalized curvilinear coordinates.

    PubMed

    Hejranfar, Kazem; Saadat, Mohammad Hossein; Taheri, Sina

    2017-02-01

    In this work, a high-order weighted essentially nonoscillatory (WENO) finite-difference lattice Boltzmann method (WENOLBM) is developed and assessed for an accurate simulation of incompressible flows. To handle curved geometries with nonuniform grids, the incompressible form of the discrete Boltzmann equation with the Bhatnagar-Gross-Krook (BGK) approximation is transformed into the generalized curvilinear coordinates and the spatial derivatives of the resulting lattice Boltzmann equation in the computational plane are solved using the fifth-order WENO scheme. The first-order implicit-explicit Runge-Kutta scheme and also the fourth-order Runge-Kutta explicit time integrating scheme are adopted for the discretization of the temporal term. To examine the accuracy and performance of the present solution procedure based on the WENOLBM developed, different benchmark test cases are simulated as follows: unsteady Taylor-Green vortex, unsteady doubly periodic shear layer flow, steady flow in a two-dimensional (2D) cavity, steady cylindrical Couette flow, steady flow over a 2D circular cylinder, and steady and unsteady flows over a NACA0012 hydrofoil at different flow conditions. Results of the present solution are compared with the existing numerical and experimental results which show good agreement. To show the efficiency and accuracy of the solution methodology, the results are also compared with the developed second-order central-difference finite-volume lattice Boltzmann method and the compact finite-difference lattice Boltzmann method. It is shown that the present numerical scheme is robust, efficient, and accurate for solving steady and unsteady incompressible flows even at high Reynolds number flows.

  5. High-order weighted essentially nonoscillatory finite-difference formulation of the lattice Boltzmann method in generalized curvilinear coordinates

    NASA Astrophysics Data System (ADS)

    Hejranfar, Kazem; Saadat, Mohammad Hossein; Taheri, Sina

    2017-02-01

    In this work, a high-order weighted essentially nonoscillatory (WENO) finite-difference lattice Boltzmann method (WENOLBM) is developed and assessed for an accurate simulation of incompressible flows. To handle curved geometries with nonuniform grids, the incompressible form of the discrete Boltzmann equation with the Bhatnagar-Gross-Krook (BGK) approximation is transformed into the generalized curvilinear coordinates and the spatial derivatives of the resulting lattice Boltzmann equation in the computational plane are solved using the fifth-order WENO scheme. The first-order implicit-explicit Runge-Kutta scheme and also the fourth-order Runge-Kutta explicit time integrating scheme are adopted for the discretization of the temporal term. To examine the accuracy and performance of the present solution procedure based on the WENOLBM developed, different benchmark test cases are simulated as follows: unsteady Taylor-Green vortex, unsteady doubly periodic shear layer flow, steady flow in a two-dimensional (2D) cavity, steady cylindrical Couette flow, steady flow over a 2D circular cylinder, and steady and unsteady flows over a NACA0012 hydrofoil at different flow conditions. Results of the present solution are compared with the existing numerical and experimental results which show good agreement. To show the efficiency and accuracy of the solution methodology, the results are also compared with the developed second-order central-difference finite-volume lattice Boltzmann method and the compact finite-difference lattice Boltzmann method. It is shown that the present numerical scheme is robust, efficient, and accurate for solving steady and unsteady incompressible flows even at high Reynolds number flows.

  6. Relaxation and Preconditioning for High Order Discontinuous Galerkin Methods with Applications to Aeroacoustics and High Speed Flows

    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

  7. The construction of arbitrary order ERKN methods based on group theory for solving oscillatory Hamiltonian systems with applications

    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.

  8. 166. GENERAL VIEW DOWN 4TH AVENUE. VIEW NORTHEAST DOWN 4TH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    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

  9. Peer Review Handbook 4th Edition, 2015

    EPA Pesticide Factsheets

    The 4th edition of EPA's Peer Review Handbook, 2015 is the most up to date version. It was prepared for the U.S. Environmental Protection Agency by Members of the Peer Review Advisory Group under the direction of EPA’s Science and Technology Policy Council

  10. 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…

  11. Second-order nonlinear optical properties in a strained InGaN/AlGaN quantum well under the intense laser field

    NASA Astrophysics Data System (ADS)

    Karimi, M. J.; Vafaei, H.

    2015-02-01

    In this work, the optical rectification and the second harmonic generation coefficients in a strained InGaN/AlGaN quantum well are studied. Impacts of the spontaneous and piezoelectric polarization fields on the potential profile are taken into account. The energy levels and wave functions are calculated using the fourth-order Runge-Kutta method and optical properties are obtained using the compact density matrix approach. Effects of intense laser field, In composition, Al composition, the well width and barrier width on the second-order nonlinear optical properties are investigated. Results reveal that the confinement potential is considerably affected by the laser field and internal electric field. Results also indicate that the resonant peaks experience a red-shift with increasing the laser field strength and barrier width. Moreover, the resonant peaks suffer a blue-shift with the increase in In and Al compositions.

  12. 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.

  13. A high-order gas-kinetic Navier-Stokes flow solver

    SciTech Connect

    Li Qibing; Xu Kun; Fu Song

    2010-09-20

    The foundation for the development of modern compressible flow solver is based on the Riemann solution of the inviscid Euler equations. The high-order schemes are basically related to high-order spatial interpolation or reconstruction. In order to overcome the low-order wave interaction mechanism due to the Riemann solution, the temporal accuracy of the scheme can be improved through the Runge-Kutta method, where the dynamic deficiencies in the first-order Riemann solution is alleviated through the sub-step spatial reconstruction in the Runge-Kutta process. The close coupling between the spatial and temporal evolution in the original nonlinear governing equations seems weakened due to its spatial and temporal decoupling. Many recently developed high-order methods require a Navier-Stokes flux function under piece-wise discontinuous high-order initial reconstruction. However, the piece-wise discontinuous initial data and the hyperbolic-parabolic nature of the Navier-Stokes equations seem inconsistent mathematically, such as the divergence of the viscous and heat conducting terms due to initial discontinuity. In this paper, based on the Boltzmann equation, we are going to present a time-dependent flux function from a high-order discontinuous reconstruction. The theoretical basis for such an approach is due to the fact that the Boltzmann equation has no specific requirement on the smoothness of the initial data and the kinetic equation has the mechanism to construct a dissipative wave structure starting from an initially discontinuous flow condition on a time scale being larger than the particle collision time. The current high-order flux evaluation method is an extension of the second-order gas-kinetic BGK scheme for the Navier-Stokes equations (BGK-NS). The novelty for the easy extension from a second-order to a higher order is due to the simple particle transport and collision mechanism on the microscopic level. This paper will present a hierarchy to construct such

  14. A neuro approach to solve fuzzy Riccati differential equations

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. ACSPRI 2014 4th International Social Science Methodology Conference Report

    DTIC Science & Technology

    2015-04-01

    behaviour (Ackland, 2014). Big Data and in particular, social media data, present both methodological challenges and opportunities in empirical social ...UNCLASSIFIED UNCLASSIFIED ACSPRI 2014 4th International Social Science Methodology Conference Report Elena Mazourenko Joint...interest to the Technology Forecasting and Futures (TFF) Group of JOAD presented at the ACSPRI 4th International Social Science Methodology conference

  20. High order parametrized maximum-principle-preserving and positivity-preserving WENO schemes on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Christlieb, Andrew J.; Liu, Yuan; Tang, Qi; Xu, Zhengfu

    2015-01-01

    In this paper, we generalize the maximum-principle-preserving (MPP) flux limiting technique developed by Xu (2013) [20] to a class of high order finite volume weighted essentially non-oscillatory (WENO) schemes for scalar conservation laws and the compressible Euler system on unstructured meshes in one and two dimensions. The key idea of this parameterized limiting technique is to limit the high order numerical flux with a first order flux which preserves the MPP or positivity-preserving (PP) property. The main purpose of this paper is to investigate the flux limiting approach with high order finite volume method on unstructured meshes which are often needed for solving some important problems on irregular domains. Truncation error analysis based on one-dimensional nonuniform meshes is presented to justify that the proposed MPP schemes can maintain third order accuracy in space and time. We also demonstrate through smooth test problems that the proposed third order MPP/PP WENO schemes coupled with a third order Runge-Kutta (RK) method attain the desired order of accuracy. Several test problems containing strong shocks and complex domain geometries are also presented to assess the performance of the schemes.

  1. Verification of higher-order discontinuous Galerkin method for hexahedral elements

    NASA Astrophysics Data System (ADS)

    Özdemir, Hüseyin; Hagmeijer, Rob; Hoeijmakers, Hendrik Willem Marie

    2005-09-01

    A high-order implementation of the Discontinuous Galerkin ( DG) method is presented for solving the three-dimensional Linearized Euler Equations on an unstructured hexahedral grid. The method is based on a quadrature free implementation and the high-order accuracy is obtained by employing higher-degree polynomials as basis functions. The present implementation is up to fourth-order accurate in space. For the time discretization a four-stage Runge-Kutta scheme is used which is fourth-order accurate. Non-reflecting boundary conditions are implemented at the boundaries of the computational domain.The method is verified for the case of the convection of a 1D compact acoustic disturbance. The numerical results show that the rate of convergence of the method is of order p+1 in the mesh size, with p the order of the basis functions. This observation is in agreement with analysis presented in the literature. To cite this article: H. Özdemir et al., C. R. Mecanique 333 (2005).

  2. An almost symmetric Strang splitting scheme for the construction of high order composition methods.

    PubMed

    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.

  3. 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.

  4. A Fourth Order Difference Scheme for the Maxwell Equations on Yee Grid

    SciTech Connect

    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.

  5. Optimal Search for Moving Targets in Continuous Time and Space using Consistent Approximations

    DTIC Science & Technology

    2011-09-01

    Polak’s method to include Runge - Kutta integration methods (see, for example, Schwartz & Polak, 1996), doing so introduces additional complications in...convergence is b−2/3. If a Runge - Kutta algorithm is used instead of Euler’s method to numerically solve the differential equations, it is clear from an analysis...Assumption IV.3 could still hold with µ = 1 114 and ν = 2. If a second-order Runge - Kutta method is used instead of Euler’s method to numerically

  6. Turbulent Flow and Large Surface Wave Events in the Marine Boundary Layers

    DTIC Science & Technology

    2013-08-22

    advancement302 Time integration is a fully explicit third-order Runge - Kutta (RK3) scheme (Spalart et al.303 1991; Sullivan et al. 1996, 2008) that uses...Stokes equations in curvilinear coordinates. J.789 Comp. Phys., 114, 18–33.790 Zheng, Z. and L. Petzold, 2006: Runge - Kutta -Chebyshev projection method ...1816–1826. Zheng, Z. and L. Petzold, 2006: Runge - Kutta - Chebyshev projection method , J. Comp. Phys., 219, 976–991. ak C D 0.1 0.2 0.3 0.4 0.50 0.5 1 1.5

  7. Properties-preserving high order numerical methods for a kinetic eikonal equation

    NASA Astrophysics Data System (ADS)

    Luo, Songting; Payne, Nicholas

    2017-02-01

    For the BGK (Bhatnagar-Gross-Krook) equation in the large scale hyperbolic limit, the density of particles can be transformed as the Hopf-Cole transformation, where the phase function converges uniformly to the viscosity solution of an effective Hamilton-Jacobi equation, referred to as the kinetic eikonal equation. In this work, we present efficient high order finite difference methods for numerically solving the kinetic eikonal equation. The methods are based on monotone schemes such as the Godunov scheme. High order weighted essentially non-oscillatory techniques and Runge-Kutta procedures are used to obtain high order accuracy in both space and time. The effective Hamiltonian is determined implicitly by a nonlinear equation given as integrals with respect to the velocity variable. Newton's method is applied to solve the nonlinear equation, where integrals with respect to the velocity variable are evaluated either by a Gauss quadrature formula or as expansions with respect to moments of the Maxwellian. The methods are designed such that several key properties such as the positivity of the viscosity solution and the positivity of the effective Hamiltonian are preserved. Numerical experiments are presented to demonstrate the effectiveness of the methods.

  8. A high-order kinetic flux-splitting method for the relativistic magnetohydrodynamics

    SciTech Connect

    Qamar, Shamsul . E-mail: shamsul.qamar@mathematik.uni-magdeburg.de; Warnecke, Gerald . E-mail: gerald.warnecke@mathematik.uni-magdeburg.de

    2005-05-01

    In this paper we extend the special relativistic hydrodynamic (SRHD) equations [L.D. Landau, E.M. Lifshitz, Fluid Mechanics, Pergamon, New York, 1987] and as a limiting case the ultra-relativistic hydrodynamic equations [M. Kunik, S. Qamar, G. Warnecke, J. Comput. Phys. 187 (2003) 572-596] to the special relativistic magnetohydrodynamics (SRMHD). We derive a flux splitting method based on gas-kinetic theory in order to solve these equations in one space dimension. The scheme is based on the direct splitting of macroscopic flux functions with consideration of particle transport. At the same time, particle 'collisions' are implemented in the free transport process to reduce numerical dissipation. To achieve high-order accuracy we use a MUSCL-type initial reconstruction and Runge-Kutta time stepping method. For the direct comparison of the numerical results, we also solve the SRMHD equations with the well-developed second-order central schemes. The 1D computations reported in this paper have comparable accuracy to the already published results. The results verify the desired accuracy, high resolution, and robustness of the kinetic flux splitting method and central schemes.

  9. Higher Order Time Integration Schemes for the Unsteady Navier-Stokes Equations on Unstructured Meshes

    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.

  10. A high-order element-based Galerkin Method for the global shallow water equations.

    SciTech Connect

    Nair, Ramachandran D.; Tufo, Henry M.; Levy, Michael Nathan

    2010-08-01

    The shallow water equations are used as a test for many atmospheric models because the solution mimics the horizontal aspects of atmospheric dynamics while the simplicity of the equations make them useful for numerical experiments. This study describes a high-order element-based Galerkin method for the global shallow water equations using absolute vorticity, divergence, and fluid depth (atmospheric thickness) as the prognostic variables, while the wind field is a diagnostic variable that can be calculated from the stream function and velocity potential (the Laplacians of which are the vorticity and divergence, respectively). The numerical method employed to solve the shallow water system is based on the discontinuous Galerkin and spectral element methods. The discontinuous Galerkin method, which is inherently conservative, is used to solve the equations governing two conservative variables - absolute vorticity and atmospheric thickness (mass). The spectral element method is used to solve the divergence equation and the Poisson equations for the velocity potential and the stream function. Time integration is done with an explicit strong stability-preserving second-order Runge-Kutta scheme and the wind field is updated directly from the vorticity and divergence at each stage, and the computational domain is the cubed sphere. A stable steady-state test is run and convergence results are provided, showing that the method is high-order accurate. Additionally, two tests without analytic solutions are run with comparable results to previous high-resolution runs found in the literature.

  11. A third-order compact gas-kinetic scheme on unstructured meshes for compressible Navier-Stokes solutions

    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.

  12. Benchmark of MEGA Code on Fast Ion Pressure Profile in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Seki, Ryosuke; Todo, Yasushi; Suzuki, Yasuhiro; Osakabe, Masaki

    2016-10-01

    As the first step for the analyses of energetic particle driven instabilities in the Large Helical Device (LHD) including the collisions of fast ions and the neutral beam injection, MEGA code is benchmarked on the classical fast ion pressure profile using the temperature and density profiles measured in the LHD experiments. In this benchmark, the MHD equilibrium is calculated with HINT code, and the beam deposition profile is calculated with HFREYA code. Since the equilibrium is not axisymmetric in LHD, the accuracy of orbit tracing is important for fast ion analyses. In the slowing down process of the MEGA code, the guiding center equation is numerically solved using the 4th order Runge-Kutta method and the linear interpolation. MEGA code is benchmarked against the results of MORH code, in which the 6th order Runge-Kutta and the 4th order spline interpolation are used. In LHD, the position of the loss boundary of fast ion is important because there are many ``re-entering fast ions'' which re-enter in plasma after they have once passed out of plasma. The effects of the position of the loss boundary on the fast ion pressure profile will be discussed, and a preliminary result of Alfven eigenmodes will be presented.

  13. Direct calculations of waves in fluid flows using high-order compact difference scheme

    NASA Technical Reports Server (NTRS)

    Yu, Sheng-Tao; Hultgren, Lennart S.; Liu, Nan-Suey

    1994-01-01

    The solution of the unsteady Euler equations by a sixth-order compact difference scheme combined with a fourth-order Runge-Kutta method is investigated. Closed-form expression for the amplification factors and their corresponding dispersion correlations are obtained by Fourier analysis of the fully discretized, two-dimensional Euler equations. The numerical dissipation, dispersion, and anisotropic effects are assessed. It is found that the Courant-Friedrichs-Lewy (CFL) limit for stable calculations is about 0.8. For a CFL number equal to 0.6, the smallest wavelength which is resolved without numerical damping is about six - eight grid nodes. For phase speeds corresponding to acoustic waves, the corresponding time period is resolved by about 200 - 300 time steps. Three numerical examples of waves in compressible flow are included: (1) sound propagation in a duct with linear shear, (2) linear wave growth in a compressible free shear layer, and (3) vortex pairing in a compressible free shear layer perturbed at two frequencies.

  14. Time-harmonic elasticity with controllability and higher-order discretization methods

    NASA Astrophysics Data System (ADS)

    Mönkölä, Sanna; Heikkola, Erkki; Pennanen, Anssi; Rossi, Tuomo

    2008-05-01

    The time-harmonic solution of the linear elastic wave equation is needed for a variety of applications. The typical procedure for solving the time-harmonic elastic wave equation leads to difficulties solving large-scale indefinite linear systems. To avoid these difficulties, we consider the original time dependent equation with a method based on an exact controllability formulation. The main idea of this approach is to find initial conditions such that after one time-period, the solution and its time derivative coincide with the initial conditions. The wave equation is discretized in the space domain with spectral elements. The degrees of freedom associated with the basis functions are situated at the Gauss-Lobatto quadrature points of the elements, and the Gauss-Lobatto quadrature rule is used so that the mass matrix becomes diagonal. This method is combined with the second-order central finite difference or the fourth-order Runge-Kutta time discretization. As a consequence of these choices, only matrix-vector products are needed in time dependent simulation. This makes the controllability method computationally efficient.

  15. 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.

  16. A new algorithm of Langevin simulation and its application to the SU(2) and SU(3) lattice gauge

    NASA Astrophysics Data System (ADS)

    Nakajima, Hideo; Furui, Sadataka

    1998-04-01

    The 2nd order Runge-Kutta scheme Langevin simulation of unquenched QCD in pseudofermion method derived from our general theory shows a behaviour as a function of the Langevin step t better than the Fukugita, Oyanagi, Ukawa's scheme.

  17. 4(th) HUPO Brain Proteome Project Workshop in Munich, Germany.

    PubMed

    Hamacher, Michael; Stephan, Christian; Palacios Bustamante, Nadine; van Hall, Andre; Marcus, Katrin; Meyer, Helmut E

    2006-01-01

    More than 70 interested colleagues attended the 4(th) Workshop of HUPO's Brain Proteome Project. The project was presented within nine talks mainly focusing on two running pilot studies as well as on data re-processing. A bioinformatics jamboree in Hinxton, UK, and the 5th Workshop taking place in Dublin next February were announced.

  18. A high-order multi-zone cut-stencil method for numerical simulations of high-speed flows over complex geometries

    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.

  19. European Code against Cancer, 4th Edition: Cancer screening.

    PubMed

    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

  20. Magnetic field effect on second order slip flow of nanofluid over a stretching/shrinking sheet with thermal radiation effect

    NASA Astrophysics Data System (ADS)

    Abdul Hakeem, A. K.; Vishnu Ganesh, N.; Ganga, B.

    2015-05-01

    The magnetic field effect on a steady two dimensional laminar radiative flow of an incompressible viscous water based nanofluid over a stretching/shrinking sheet with second order slip boundary condition is investigated both analytically and numerically. The governing partial differential equations are reduced to nonlinear ordinary differential equations by means of Lie symmetry group transformations. The dimensionless governing equations for this investigation are solved analytically using hyper-geometric function and numerically by the fourth order Runge-Kutta method with the shooting technique. A unique exact solution exists for momentum equation in stretching sheet case and dual solutions are obtained for shrinking sheet case which has upper and lower branches. It is found that the lower branch solution vanishes in the presence of higher magnetic field. The velocity and temperature profiles, the local skin friction coefficient and the reduced Nusselt number are examined and discussed for different spherical nanoparticles such as Au, Ag, Cu, Al, Al2 O3 and TiO2. A comparative study between the previously published results and the present analytical and numerical results for a special case is found to be in good agreement.

  1. 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.

  2. 4th International Plant Biomechanics Conference Proceedings (Abstracts)

    SciTech Connect

    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.

  3. Summary of the 4th Nordic Symposium on Digital Pathology

    PubMed Central

    Lundström, Claes; Waltersson, Marie; Persson, Anders; Treanor, Darren

    2017-01-01

    The Nordic symposium on digital pathology (NDP) was created to promote knowledge exchange across stakeholders in health care, industry, and academia. In 2016, the 4th NDP installment took place in Linköping, Sweden, promoting development and collaboration in digital pathology for the benefit of routine care advances. This article summarizes the symposium, gathering 170 attendees from 13 countries. This summary also contains results from a survey on integrated diagnostics aspects, in particular radiology-pathology collaboration. PMID:28382222

  4. 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

  5. High order well-balanced finite volume WENO schemes and discontinuous Galerkin methods for a class of hyperbolic systems with source terms

    SciTech Connect

    Xing Yulong . E-mail: xing@dam.brown.edu; Shu Chiwang . E-mail: shu@dam.brown.edu

    2006-05-20

    Hyperbolic balance laws have steady state solutions in which the flux gradients are nonzero but are exactly balanced by the source term. In our earlier work [J. Comput. Phys. 208 (2005) 206-227; J. Sci. Comput., accepted], we designed a well-balanced finite difference weighted essentially non-oscillatory (WENO) scheme, which at the same time maintains genuine high order accuracy for general solutions, to a class of hyperbolic systems with separable source terms including the shallow water equations, the elastic wave equation, the hyperbolic model for a chemosensitive movement, the nozzle flow and a two phase flow model. In this paper, we generalize high order finite volume WENO schemes and Runge-Kutta discontinuous Galerkin (RKDG) finite element methods to the same class of hyperbolic systems to maintain a well-balanced property. Finite volume and discontinuous Galerkin finite element schemes are more flexible than finite difference schemes to treat complicated geometry and adaptivity. However, because of a different computational framework, the maintenance of the well-balanced property requires different technical approaches. After the description of our well-balanced high order finite volume WENO and RKDG schemes, we perform extensive one and two dimensional simulations to verify the properties of these schemes such as the exact preservation of the balance laws for certain steady state solutions, the non-oscillatory property for general solutions with discontinuities, and the genuine high order accuracy in smooth regions.

  6. A high-order numerical algorithm for DNS of low-Mach-number reactive flows with detailed chemistry and quasi-spectral accuracy

    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.

  7. Some numerical methods for integrating systems of first-order ordinary differential equations

    NASA Technical Reports Server (NTRS)

    Clark, N. W.

    1969-01-01

    Report on numerical methods of integration includes the extrapolation methods of Bulirsch-Stoer and Neville. A comparison is made nith the Runge-Kutta and Adams-Moulton methods, and circumstances are discussed under which the extrapolation method may be preferred.

  8. Influence of higher-order effects on pulsating solutions, stationary solutions and moving fronts in the presence of linear and nonlinear gain/loss and spectral filtering

    NASA Astrophysics Data System (ADS)

    Uzunov, Ivan M.; Arabadzhiev, Todor N.; Georgiev, Zhivko D.

    2015-08-01

    We have studied the impact of the higher-order effects: intrapulse Raman scattering (IRS), third-order of dispersion (TOD) and self-steepening (SS) on pulsating solutions, moving fronts and stationary solutions of the complex cubic-quintic Ginzburg-Landau equation (CCQGLE) found in Tsoy and Akhmediev (2005) as well as on the solutions presented in Uzunov et al. (2014). The applied basic equation generalizes the CCQGLE with the IRS, TOD and SS effects. A finite-dimensional dynamical system has been derived using the method of moments. Applying the derived dynamical system alongside with the numerical solution of the generalized CCQGLE performed by means of the fourth-order Runge-Kutta interaction picture method we have found that the influence of IRS and SS is stronger than the impact of TOD for the solutions of Tsoy and Akhmediev (2005). Perturbed pulsating solutions, moving fronts and stationary solutions in the presence of IRS, SS and TOD have been numerically observed. They exist up to some critical values of the parameters of perturbations. For the values of parameters larger than the critical ones the pulsating solutions are transformed into stable stationary solutions or unstable solutions. New localized fluctuating and stationary solutions have been obtained for fairly large values of parameters of IRS and TOD, respectively. The transformation of the stable stationary solution of Uzunov et al. (2014) under the influence of SS into pulsating solution has been numerically observed.

  9. Report of the 4th European Zebrafish Principal Investigator Meeting.

    PubMed

    Lopes, Susana S; Distel, Martin; Linker, Claudia; Fior, Rita; Monteiro, Rui; Bianco, Isaac H; Portugues, Ruben; Strähle, Uwe; Saúde, Leonor

    2016-12-01

    The European Zebrafish Principal Investigator Meeting (EZPM) is an ideal forum for group leaders using this fantastic animal model not only to discuss science but also to strengthen their interactions, to push forward technological advances, and to define guidelines for the use of this fish in research. The city of Lisbon (Portugal) was voted by the European group leaders to be the setting for the 4th EZPM, and the organizing committee, composed by Leonor Saúde (iMM Lisboa, PT), Susana Lopes (CEDOC, PT), Michael Orger (Champalimaud Foundation, PT), Rui Oliveira (ISPA, PT), and António Jacinto (CEDOC, PT), was very enthusiastic to organize a productive event. The 4th EZPM took place from March 15 to 19 at Pavilhão do Conhecimento, a Science Museum and Educational Center winner of The Great Prize FAD of Arquitecture 1999 and The Society for Environmental Graphic Design Award 2011. Over 5 days, 135 group leaders (89 men and 46 women) coming from 19 different European countries and also from the United States, Turkey, Israel, Chile, and Singapore presented and discussed their recent research achievements. In addition to the scientific oral and poster presentations, the group leaders gathered in very lively community sessions on morphants versus mutants (chaired by Didier Stainier, Max Planck Institute for Heart and Lung Research, DE), funding issues (chaired by Uwe Strahle, KIT-ITG, DE), and gender equality (chaired by Corinne Houart, KCL, United Kingdom). One of the highlights of the 4th EZPM was the guided visit to Oceanário de Lisboa, an international award-winning place that celebrates life with a stunning display of living aquatic creatures.

  10. 4TH Marine Division Operation Plan Number 49-44

    DTIC Science & Technology

    1944-12-26

    I / i i -4- A. o. o o o 3 4-’ 4TH MARINE DIVISION 54 OPERATION PLAN NO. 49-44 DECLASSIFIED IAW CLIASSIFICATION $4...INTO ENEMY HANDS. LUISrAR! UNCLASS0FIDo .-O UNCLASSIFIED ri LL!n .. I . 155 - - o.- sr Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...the remainder of O-1 within Z, repared or further OPN PLAN 49-44 - 1 - O1 :?’:¢ . ... ~·~:~ I I - I --" , I %,"_’,: A I 1-W_ , - I I ---. -

  11. 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

  12. 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.

  13. Rate of Missing Socioeconomic Factors in the 4th KNHANES.

    PubMed

    Park, Hyun Ah

    2012-11-01

    This study is to assess how missing values in socioeconomic status (SES) variables were handled in the Korean Journal of Family Medicine (KJFM) article using the Korea National Health and Nutrition Examination Survey (KNHANES) data and to estimate the rate of missing SES variables from the 4th KNHANES. We searched all original articles published in the KJFM from 2007 to 2011 and identified those that used KNHANES as their primary source of data. None of the 11 articles which presented KNHANES SES variables took into account of omitions in the analysis. The estimated rate of missing data on education, household income, marital status, and occupation data of the 4th KNHANES was 0.3 (0.05)%, 2.7 (0.2)%, 0.5 (0.1)%, and 9.4 (0.9)%, respectively. When all four variables were used simultaneously, the rates increased to 11.8 (0.9)%. Respondents with missing household income tended to be older (P < 0.001), less educated (P < 0.001), and more likely to be unemployed (P < 0.001), and widowed (P < 0.001). A similar relationship was shown for missing occupation data. Omissions in SES variables in KNHANES were related to certain characteristics of study participants. Researchers using KNHANES data should keep in mind the possible bias which can be introduced by missing SES values.

  14. Native American Students' Understanding of Geologic Time Scale: 4th-8th Grade Ojibwe Students' Understanding of Earth's Geologic History

    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…

  15. 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.

  16. High-order finite-volume methods for the shallow-water equations on the sphere

    NASA Astrophysics Data System (ADS)

    Ullrich, Paul A.; Jablonowski, Christiane; van Leer, Bram

    2010-08-01

    This paper presents a third-order and fourth-order finite-volume method for solving the shallow-water equations on a non-orthogonal equiangular cubed-sphere grid. Such a grid is built upon an inflated cube placed inside a sphere and provides an almost uniform grid point distribution. The numerical schemes are based on a high-order variant of the Monotone Upstream-centered Schemes for Conservation Laws (MUSCL) pioneered by van Leer. In each cell the reconstructed left and right states are either obtained via a dimension-split piecewise-parabolic method or a piecewise-cubic reconstruction. The reconstructed states then serve as input to an approximate Riemann solver that determines the numerical fluxes at two Gaussian quadrature points along the cell boundary. The use of multiple quadrature points renders the resulting flux high-order. Three types of approximate Riemann solvers are compared, including the widely used solver of Rusanov, the solver of Roe and the new AUSM +-up solver of Liou that has been designed for low-Mach number flows. Spatial discretizations are paired with either a third-order or fourth-order total-variation-diminishing Runge-Kutta timestepping scheme to match the order of the spatial discretization. The numerical schemes are evaluated with several standard shallow-water test cases that emphasize accuracy and conservation properties. These tests show that the AUSM +-up flux provides the best overall accuracy, followed closely by the Roe solver. The Rusanov flux, with its simplicity, provides significantly larger errors by comparison. A brief discussion on extending the method to arbitrary order-of-accuracy is included.

  17. 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.

  18. 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...

  19. Can astronomy enhance UNESCO World Heritage recognition? The paradigm of 4th Dynasty Egyptian pyramids

    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.

  20. Adaptive Runge-Kutta integration for stiff systems: Comparing Nosé and Nosé-Hoover dynamics for the harmonic oscillator

    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.

  1. Managing haemophilia for life: 4th Haemophilia Global Summit.

    PubMed

    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.

  2. The 4th Concept Detector for the ILC

    NASA Astrophysics Data System (ADS)

    Mazzacane, A.

    2010-05-01

    The 4th Concept Detector is designed for high precision measurements of Physics processes accessible at ILC. It consists of four basic subsystems: a pixel vertex detector for high precision vertex definitions, impact parameter tagging and near-beam occupancy reduction; a cluster-counting low-mass drift chamber for robust pattern recognition with over 100 three-dimensional space-points each with about 55 μm resolution, 3.5% specific ionization measurement; a high precision dual-readout fiber calorimeter, complemented with an EM dual-readout crystal calorimeter, both with time-history readout, for the energy measurement of hadrons, jets, electrons, photons, missing momentum, and the tagging of muons; and, an iron-free dual-solenoid to return the flux and provide a second field region for the inverse direction bending of muons in a gas volume to achieve high acceptance and good muon momentum resolution. All four subsystems separately achieve the important scientific goal to be 2-to-10 times better than the already excellent LEP detectors, Aleph, Delphi, L3, and Opal. All four sub-detector will be described along with their performance and Physics capabilities obtained with full simulation studies.

  3. European Code against Cancer 4th Edition: Diet and cancer.

    PubMed

    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.

  4. 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.

  5. European Code against Cancer, 4th Edition: Tobacco and cancer.

    PubMed

    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".

  6. PREFACE: 4th International Hadron Physics Conference (TROIA'14)

    NASA Astrophysics Data System (ADS)

    Dağ, Hüseyin; Erkol, Güray; Küçükarslan, Ayşe; Özpineci, Altuğ

    2014-11-01

    The 4th International Conference on Hadron Physics, TROIA'14, was held at Canakkale, Turkey on 1-5 July 2014. Ozyegin University, Middle East Technical University, Canakkale Onsekiz Mart University, Turkish Atomic Energy Authority and HadronPhysics2 Consortium sponsored the conference. It aimed at bringing together the experts and the young scientists working on experimental and theoretical hadron physics. About 50 participants from 10 countries attended the conference. The topics covered included: . Chiral Perturbation Theory . QCD Sum Rules . Effective Field Theory . Exotic Hadrons . Hadron Properties from Lattice QCD . Experimental Results and Future Perspectives . Hadronic Distribution Amplitudes The conference presentations were organized such that the morning sessions contained invited talks and afternoon sessions were devoted to contributed talks. The speakers of the invited talks were: C. Alexandrou, A. Gal, L. Tolos, J.R. Pelaez and M. Schindler. We had also guest speakers D. A. Demir and T. Senger. The conference venue was a resort hotel around Canakkale. As a social program, a guided full-day excursion to the excavation site of the ancient Troia town and Assos was organized. We believe that this conference provided a medium for young scientists and experts in the field to effectively communicate and share ideas. We would like to express our sincere thanks to supporting agencies and to all participants for their contributions and stimulating discussions. We are also grateful to the Scientific Secretary, Bora Işıldak, and all other members of the Organizing Committee for their patience and efforts. 30.10.2014 The Editors

  7. Plasma-Based Studies on 4th Generation Light Sources

    SciTech Connect

    Lee, R W; Baldis, H A; Cauble, R C; Landen, O L; Wark, J S; Ng, A; Rose, S J; Lewis, C; Riley, D; Gauthier, J-C; Audebert, P

    2000-11-28

    The construction of a short pulse tunable x-ray laser source will be a watershed for plasma-based and warm dense matter research. The areas we will discuss below can be separated broadly into warn dense matter (WDM) research, laser probing of near solid density plasmas, and laser-plasma spectroscopy of ions in plasmas. The area of WDM refers to that part of the density-temperature phase space where the standard theories of condensed matter physics and/or plasma statistical physics are invalid. Warm dense matter, therefore, defines a region between solids and plasmas, a regime that is found in planetary interiors, cool dense stars, and in every plasma device where one starts from a solid, e.g., laser-solid matter produced plasma as well as all inertial fusion schemes. The study of dense plasmas has been severely hampered by the fact that laser-based methods have been unavailable. The single most useful diagnostic of local plasma conditions, e.g., the temperature (T{sub e}), the density (n{sub e}), and the ionization (Z), has been Thomson scattering. However, due to the fact that visible light will not propagate at electron densities, n{sub e}, {ge} 10{sup 22} cm{sup -3} implies dense plasmas can not be probed. The 4th generation sources, LCLS and Tesla will remove these restrictions. Laser-based plasma spectroscopic techniques have been used with great success to determine the line shapes of atomic transitions in plasmas, study the population kinetics of atomic systems embedded in plasmas, and look at redistribution of radiation. However. the possibilities end for plasmas with n{sub e} {ge} 10{sup 22} since light propagation through the medium is severely altered by the plasma. The entire field of high Z plasma kinetics from laser produced plasma will then be available to study with the tunable source.

  8. 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.

  9. 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

  10. Numerical Investigation of a Model Scramjet Combustor Using DDES

    NASA Astrophysics Data System (ADS)

    Shin, Junsu; Sung, Hong-Gye

    2017-04-01

    Non-reactive flows moving through a model scramjet were investigated using a delayed detached eddy simulation (DDES), which is a hybrid scheme combining Reynolds averaged Navier-Stokes scheme and a large eddy simulation. The three dimensional Navier-Stokes equations were solved numerically on a structural grid using finite volume methods. An in-house was developed. This code used a monotonic upstream-centered scheme for conservation laws (MUSCL) with an advection upstream splitting method by pressure weight function (AUSMPW+) for space. In addition, a 4th order Runge-Kutta scheme was used with preconditioning for time integration. The geometries and boundary conditions of a scramjet combustor operated by DLR, a German aerospace center, were considered. The profiles of the lower wall pressure and axial velocity obtained from a time-averaged solution were compared with experimental results. Also, the mixing efficiency and total pressure recovery factor were provided in order to inspect the performance of the combustor.

  11. An adjoint method for a high-order discretization of deforming domain conservation laws for optimization of flow problems

    NASA Astrophysics Data System (ADS)

    Zahr, M. J.; Persson, P.-O.

    2016-12-01

    The fully discrete adjoint equations and the corresponding adjoint method are derived for a globally high-order accurate discretization of conservation laws on parametrized, deforming domains. The conservation law on the deforming domain is transformed into one on a fixed reference domain by the introduction of a time-dependent mapping that encapsulates the domain deformation and parametrization, resulting in an Arbitrary Lagrangian-Eulerian form of the governing equations. A high-order discontinuous Galerkin method is used to discretize the transformed equation in space and a high-order diagonally implicit Runge-Kutta scheme is used for the temporal discretization. Quantities of interest that take the form of space-time integrals are discretized in a solver-consistent manner. The corresponding fully discrete adjoint method is used to compute exact gradients of quantities of interest along the manifold of solutions of the fully discrete conservation law. These quantities of interest and their gradients are used in the context of gradient-based PDE-constrained optimization. The adjoint method is used to solve two optimal shape and control problems governed by the isentropic, compressible Navier-Stokes equations. The first optimization problem seeks the energetically optimal trajectory of a 2D airfoil given a required initial and final spatial position. The optimization solver, driven by gradients computed via the adjoint method, reduced the total energy required to complete the specified mission nearly an order of magnitude. The second optimization problem seeks the energetically optimal flapping motion and time-morphed geometry of a 2D airfoil given an equality constraint on the x-directed impulse generated on the airfoil. The optimization solver satisfied the impulse constraint to greater than 8 digits of accuracy and reduced the required energy between a factor of 2 and 10, depending on the value of the impulse constraint, as compared to the nominal configuration.

  12. Study of vortex ring dynamics in the nonlinear Schrodinger equation utilizing GPU-accelerated high-order compact numerical integrators

    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.

  13. 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...

  14. 76 FR 37650 - Safety Zone; 4th of July Festival Berkeley Marina Fireworks Display Berkeley, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 4th of July Festival Berkeley Marina Fireworks Display Berkeley, CA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast... Berkeley Pier, Berkeley, CA in support of the 4th of July Festival Berkeley Marina Fireworks...

  15. 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…

  16. 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...

  17. 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…

  18. A novel class of highly efficient and accurate time-integrators in nonlinear computational mechanics

    NASA Astrophysics Data System (ADS)

    Wang, Xuechuan; Atluri, Satya N.

    2017-01-01

    A new class of time-integrators is presented for strongly nonlinear dynamical systems. These algorithms are far superior to the currently common time integrators in computational efficiency and accuracy. These three algorithms are based on a local variational iteration method applied over a finite interval of time. By using Chebyshev polynomials as trial functions and Dirac-Delta functions as the test functions over the finite time interval, the three algorithms are developed into three different discrete time-integrators through the collocation method. These time integrators are labeled as Chebyshev local iterative collocation methods. Through examples of the forced Duffing oscillator, the Lorenz system, and the multiple coupled Duffing equations (which arise as semi-discrete equations for beams, plates and shells undergoing large deformations), it is shown that the new algorithms are far superior to the 4th order Runge-Kutta and ODE45 of MATLAB, in predicting the chaotic responses of strongly nonlinear dynamical systems.

  19. Haar wavelet solution of the MHD Jeffery-Hamel flow and heat transfer in Eyring-Powell fluid

    NASA Astrophysics Data System (ADS)

    Khan, Najeeb Alam; Sultan, Faqiha; Shaikh, Amber; Ara, Asmat; Rubbab, Qammar

    2016-11-01

    This study deals with the numerical investigation of Jeffery-Hamel flow and heat transfer in Eyring-Powell fluid in the presence of an outer magnetic field by using Haar wavelet method. Jeffery-Hamel flows occur in various practical situations involving flow between two non-parallel walls. Applications of such fluids in biological and industrial sciences brought a great concern to the investigation of flow characteristics in converging and diverging channels. A suitable similarity transformation is applied to transform the nonlinear coupled partial differential equations (PDEs) into nonlinear coupled ordinary differential equations (ODEs), which govern the momentum and heat transfer properties of the fluid. Due to the high nonlinearity of resulting coupled ODEs, the exact solution is unlikely. Thus, the solution is approximated using a numerical scheme based on Haar wavelets and the results are verified by comparing with 4th order Runge-Kutta results.

  20. Portable dynamic positioning control system on a barge in short-crested waves using the neural network algorithm

    NASA Astrophysics Data System (ADS)

    Fang, Ming-chung; Lee, Zi-yi

    2013-08-01

    This paper develops a nonlinear mathematical model to simulate the dynamic motion behavior of the barge equipped with the portable outboard Dynamic Positioning (DP) system in short-crested waves. The self-tuning Proportional-Derivative (PD) controller based on the neural network algorithm is applied to control the thrusters for optimal adjustment of the barge position in waves. In addition to the wave, the current, the wind and the nonlinear drift force are also considered in the calculations. The time domain simulations for the six-degree-of-freedom motions of the barge with the DP system are solved by the 4th order Runge-Kutta method which can compromise the efficiency and the accuracy of the simulations. The technique of the portable alternative DP system developed here can serve as a practical tool to assist those ships without being equipped with the DP facility while the dynamic positioning missions are needed.

  1. Thermo-miscible fluid displacement in a porous media flow

    NASA Astrophysics Data System (ADS)

    Ward, Thomas; Soori, Tejaswi

    2016-11-01

    The an-isoviscous displacement of a generalized Newtonian liquid in an impulsively heated axisymmetric pipe geometry is studied at low to moderate Reynolds numbers using computational analysis. The temperature dependent viscosity is modeled using an empirical correlation that has been shown to fit experimental data for a range of temperature values. The governing Cauchy momentum equations for the generalized Newtonian fluid are solved in primitive variables using a 4th order Runge-Kutta method. For viscous liquids with a high Prandtl number radial and axial variations in temperature are significant leading to modification of the steady state pressure loss when compared to isoviscous displacements. We characterize the steady state pressure loss and average Nusselt number using the Reynolds 0 . 1 < Re < 10 , viscous Atwood 0 < At < 0 . 8 , and Peclet 100 < Pe < 10 , 000 numbers.

  2. Time-reversed particle dynamics calculation with field line tracing at Titan - an update

    NASA Astrophysics Data System (ADS)

    Bebesi, Zsofia; Erdos, Geza; Szego, Karoly; Juhasz, Antal; Lukacs, Katalin

    2014-05-01

    We use CAPS-IMS Singles data of Cassini measured between 2004 and 2010 to investigate the pickup process and dynamics of ions originating from Titan's atmosphere. A 4th order Runge-Kutta method was applied to calculate the test particle trajectories in a time reversed scenario, in the curved magnetic environment. We evaluated the minimum variance directions along the S/C trajectory for all Cassini flybys during which the CAPS instrument was in operation, and assumed that the field was homogeneous perpendicular to the minimum variance direction. We calculated the magnetic field lines with this method along the flyby orbits and we could determine those observational intervals when Cassini and the upper atmosphere of Titan could be magnetically connected. We used three ion species (1, 2 and 16 amu ions) for time reversed tracking, and also considered the categorization of Rymer et al. (2009) and Nemeth et al. (2011) for further features studies.

  3. XTROEM-FV: a new code for computational astrophysics based on very high order finite-volume methods - II. Relativistic hydro- and magnetohydrodynamics

    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.

  4. State-Space Modeling, System Identification and Control of a 4th Order Rotational Mechanical System

    DTIC Science & Technology

    2009-12-01

    state-space form. Identification of the state-space parameters was accomplished using the parameter estimation function in Matlab’s System ... Identification Toolbox utilizing experimental input/output data. The identified model was then constructed in Simulink and the accuracy of the identified model

  5. 18. DETAILED OFFSHORE VIEW OF 4TH TEE, LOOKING NORTHWEST, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAILED OFFSHORE VIEW OF 4TH TEE, LOOKING NORTHWEST, SHOWING TRANSITION FROM WOOD BENTS TO CONCRETE BENTS - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  6. European Code against Cancer 4th Edition: Infections and Cancer.

    PubMed

    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.

  7. Qualification of the 4th stage propulsor of the Brazilian launcher. SLV: A new sounding rocket

    NASA Astrophysics Data System (ADS)

    Boscov, Jayme; Toyama, Wilson Katsumi

    1989-06-01

    The development of the Satellite Launcher Vehicle (SLV) is presented. In particular, the attention is focused on the acquisition of the propulsion parameters of the 4th stage propulsor. The device feasibility analysis is considered. The system consists of a two staged sounding rocket. Its second stage contains the SVL, which can be launched by the 4th stage propulsor to a height range of about 50 to 60 km.

  8. Exponentially fitted symplectic integrator

    NASA Astrophysics Data System (ADS)

    Simos, T. E.; Vigo-Aguiar, Jesus

    2003-01-01

    In this paper a procedure for constructing efficient symplectic integrators for Hamiltonian problems is introduced. This procedure is based on the combination of the exponential fitting technique and symplecticness conditions. Based on this procedure, a simple modified Runge-Kutta-Nyström second-order algebraic exponentially fitted method is developed. We give explicitly the symplecticness conditions for the modified Runge-Kutta-Nyström method. We also give the exponential fitting and trigonometric fitting conditions. Numerical results indicate that the present method is much more efficient than the “classical” symplectic Runge-Kutta-Nyström second-order algebraic method introduced by M.P. Calvo and J.M. Sanz-Serna [J. Sci. Comput. (USA) 14, 1237 (1993)]. We note that the present procedure is appropriate for all near-unimodal systems.

  9. 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

  10. International Symposium on Stratified Flows (4th) Held in Grenoble, France on June 29-July 2, 1994. Volume 3

    DTIC Science & Technology

    1994-10-10

    differential geometry aproach to geophysical flows " - to be published in Phys.Letters A 9 The structure of the turbulent wake and the random internal wave field... flows , the Sc effects should come into play especially when Re drop to values of the order of [(cX/tX2 ,n(Sc) -2; such low Reynolds numbers are not...proceedings 29 June - 2 July 1994 4. Title & subtitle 5a. Contract or Grant # 4th International Symposium on Stratified Flows N00014-94-J-9018 5b

  11. European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer.

    PubMed

    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.

  12. Cutting orientations for non-complex parts in 4th axis machining

    NASA Astrophysics Data System (ADS)

    Osman Zahid, M. N.; Case, K.; Watts, D. M.

    2016-02-01

    The application of Computer Numerically Controlled (CNC) machining for Rapid Manufacturing processes (CNC-RM) exploits the innate potential of 4th axis machining. The use of an indexer allows the workpiece to be rotated to various orientations which directly increased the region accessible to the cutting tool. However, in order to avoid thin webs and preserve tool life, cutting must be executed with a minimum of three orientations even for geometrically simple parts. Recent findings have suggested the separation of cutting orientations into roughing and finishing operations. Thus, the selection of orientations in finishing processes becomes more flexible and independent. This study was conducted to identify the effects of using a minimum of two cutting orientations in finishing operations for CNC-RM applications. This method is only applicable for non-complex parts where all the features can be machined from two directions. The results of the study illustrate the positive effects of minimizing the number of orientations. Despite improvement in machining operations, the complexity in defining the cutting orientations was also reduced.

  13. Derivation of Explicit Difference Schemes for Ordinary Differential Equations with the Aid of Lagrange-Burmann Expansions

    NASA Astrophysics Data System (ADS)

    Vorozhtsov, Evgenii V.

    We propose to derive the explicit multistage methods of the Runge-Kutta type for ordinary differential equations (ODEs) with the aid of the expansion of grid functions into the Lagrange-Burmann series. New explicit first- and second-order methods are derived, which are applied to the numerical integration of the Cauchy problem for a moderately stiff ODE system. It turns out that the L 2 norm of the error of the solution obtained by the new numerical second-order method is 50 times smaller than in the case of the classical second-order Runge-Kutta method.

  14. Systematically frameshifting by deletion of every 4th or 4th and 5th nucleotides during mitochondrial transcription: RNA self-hybridization regulates delRNA expression.

    PubMed

    Seligmann, Hervé

    2016-01-01

    In mitochondria, secondary structures punctuate post-transcriptional RNA processing. Recently described transcripts match the human mitogenome after systematic deletions of every 4th, respectively every 4th and 5th nucleotides, called delRNAs. Here I explore predicted stem-loop hairpin formation by delRNAs, and their associations with delRNA transcription and detected peptides matching their translation. Despite missing 25, respectively 40% of the nucleotides in the original sequence, del-transformed sequences form significantly more secondary structures than corresponding randomly shuffled sequences, indicating biological function, independently of, and in combination with, previously detected delRNA and thereof translated peptides. Self-hybridization decreases delRNA abundances, indicating downregulation. Systematic deletions of the human mitogenome reveal new, unsuspected coding and structural informations.

  15. High-Order Residual-Distribution Hyperbolic Advection-Diffusion Schemes: 3rd-, 4th-, and 6th-Order

    DTIC Science & Technology

    2014-06-01

    January 2013. 20N. R. Merski. Reduction and analysis of phosphor thermography data with the IHEAT software package. In 36th AIAA Aerospace Sciences...and n. R. Merski. X- 33 Experimental Aeroheating at Mach 6 Using Phosphor Thermography . J. Spacecraft and Rockets, 38:635–645, 2001. 22M. Ricchiuto, R

  16. A Novel Method for Prediction of Nonlinear Aeroelastic Responses

    DTIC Science & Technology

    2010-01-01

    time, (3.59) is integrated using a fourth-order Runge - Kutta method (Gerald and Wheatley, 2004): Yn+1 = Yn + 1 6 ∆t (k1 + 2k2 + 2k3 + k4) , (3.61...Orthogonal De- composition 10 2.1 Acceleration Techniques for the Proper Orthogonal Decomposition Method . . . . . 10 2.1.1 Database Splitting...a Runge - Kutta -Fehlberg routine (Fehlberg, 1969). Further details of the implementation are given in (Brenner et al., 2009). For this test case, the

  17. 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.

  18. 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.

  19. Execution of novel explicit RKARMS(4,4) technique in determining initial configurations of extra-solar protoplanets formed by disk instability

    NASA Astrophysics Data System (ADS)

    Paul, Gour Chandra; Senthilkumar, Sukumar

    2016-06-01

    Implementation of a novel embedded Runge-Kutta fourth order four stage arithmetic root mean square technique to determine initial configurations of extra-solar protoplanets formed by gravitational instability is the main goal of this present paper. A general mathematical framework for the introduced numerical technique is described in addition to error estimation description. It is noticed that the numerical outputs through the employed novel RKARMS(4,4) method are found to be more effective and efficient in comparison with the results obtained by the classical Runge-Kutta technique.

  20. European Code against Cancer 4th Edition: Environment, occupation and cancer.

    PubMed

    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."

  1. Improving the Attitudes of 4th Graders toward Older People through a Multidimensional Intergenerational Program

    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…

  2. 75 FR 34639 - Safety Zone; Reedville July 4th Celebration, Cockrell's Creek, Reedville, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Reedville July 4th Celebration, Cockrell's... establishing a temporary safety zone on Cockrell's Creek in the vicinity of Reedville, Virginia in support of... impracticable. Delaying the effective date would be contrary to the safety zone's intended objectives...

  3. 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...

  4. 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...

  5. MAIN GATE, INTERSECTION OF 4TH AVE (200 NORTH) AND N ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    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

  6. Polarimetric Microwave Emission from Snow Surface: 4th Strokes Component Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of ice on the polarimetric 4th Stokes component observations is investigated using WindSat data over Antarctica. The difference in the magnitude of the signal observed during (July 2003) and summer (February 2004) months is investigated using a second harmonic sine function of the azimuth...

  7. 33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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 area...) in length, carrying persons for the purpose of viewing the fireworks, may take position in an...

  8. 33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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 area...) in length, carrying persons for the purpose of viewing the fireworks, may take position in an...

  9. 33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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 area...) in length, carrying persons for the purpose of viewing the fireworks, may take position in an...

  10. 33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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 area...) in length, carrying persons for the purpose of viewing the fireworks, may take position in an...

  11. 33 CFR 165.166 - Safety Zone: Macy's July 4th Fireworks, East River, NY.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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 area...) in length, carrying persons for the purpose of viewing the fireworks, may take position in an...

  12. 75 FR 33170 - Safety Zone; City of Martinez 4th of July Fireworks, Martinez, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; City of Martinez 4th of July Fireworks, Martinez, CA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone for the launching of fireworks being sponsored by the City of...

  13. 11. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO NORTHEAST, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    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

  14. 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. 4th level of 1945 warehouse indicating drag conveyor. From here ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    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

  16. Convergence analysis of combinations of different methods

    SciTech Connect

    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.

  17. 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.

  18. Effects of Public Preschool Expenditures on the Test Scores of 4th Graders: Evidence from TIMSS

    PubMed Central

    Waldfogel, Jane; Zhai, Fuhua

    2011-01-01

    This study examines the effects of public preschool expenditures on the math and science scores of 4th graders, holding constant child, family, and school characteristics, other relevant social expenditures, and country and year effects, in seven Organization for Economic Co-operation and Development (OECD) countries -- Australia, Japan, Netherlands, New Zealand, Norway, U.K., and U.S -- using data from the 1995 and 2003 Trends in International Mathematics and Science Study (TIMSS). Our results indicate that there are small but significant positive effects of public preschool expenditures on the math and science scores of 4th graders and preschool expenditures reduce the risk of children scoring at the low level of proficiency. We also find some evidence that children from low-resource homes and homes where the test language is not always spoken may tend to gain more from increased public preschool expenditures than other children,. PMID:21442008

  19. 11th National Meeting of Organic Chemistry and 4th Meeting of Therapeutic Chemistry

    PubMed Central

    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

  20. LESSONS LEARNED, HEADQUARTERS, 4TH BATTALION (AW)(SP), 60TH ARTILLERY

    DTIC Science & Technology

    The 4th Battalion (AW)(SP) 60th Artillery with attached Battery E (MG), 41st Artillery, remained assigned to I Field Force Vietnam, attached to I ...Battalion (AW)(SP), 60th Artillery, with attached Battery E (MG), 41st Artillery, was detached from 41st Artillery Group and fully attached to I Field Force...States and Free World Military Assistance Forces throughout the II Corps Tactical Zone and the I Corps Tactical Zone.

  1. 10. 4TH FLOOR, HOTEL SOAP LINE No. 6 TO SOUTHWEST, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    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

  2. 11(th) National Meeting of Organic Chemistry and 4(th) Meeting of Therapeutic Chemistry.

    PubMed

    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.

  3. 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.

  4. ERKN integrators for systems of oscillatory second-order differential equations

    NASA Astrophysics Data System (ADS)

    Wu, Xinyuan; You, Xiong; Shi, Wei; Wang, Bin

    2010-11-01

    For systems of oscillatory second-order differential equations y+My=f with M∈R, a symmetric positive semi-definite matrix, X. Wu et al. have proposed the multidimensional ARKN methods [X. Wu, X. You, J. Xia, Order conditions for ARKN methods solving oscillatory systems, Comput. Phys. Comm. 180 (2009) 2250-2257], which are an essential generalization of J.M. Franco's ARKN methods for one-dimensional problems or for systems with a diagonal matrix M=wI [J.M. Franco, Runge-Kutta-Nyström methods adapted to the numerical integration of perturbed oscillators, Comput. Phys. Comm. 147 (2002) 770-787]. One of the merits of these methods is that they integrate exactly the unperturbed oscillators y+My=0. Regretfully, even for the unperturbed oscillators the internal stages Y of an ARKN method fail to equal the values of the exact solution y(t) at t+ch, respectively. Recently H. Yang et al. proposed the ERKN methods to overcome this drawback [H.L. Yang, X.Y. Wu, Xiong You, Yonglei Fang, Extended RKN-type methods for numerical integration of perturbed oscillators, Comput. Phys. Comm. 180 (2009) 1777-1794]. However, the ERKN methods in that paper are only considered for the special case where M is a diagonal matrix with nonnegative entries. The purpose of this paper is to extend the ERKN methods to the general case with M∈R, and the perturbing function f depends only on y. Numerical experiments accompanied demonstrates that the ERKN methods are more efficient than the existing methods for the computation of oscillatory systems. In particular, if M∈R is a symmetric positive semi-definite matrix, it is highly important for the new ERKN integrators to show the energy conservation in the numerical experiments for problems with Hamiltonian H(p,q)=1/2 >pp+1/2 >qMq+V(q) in comparison with the well-known methods in the scientific literature. Those so called separable Hamiltonians arise in many areas of physical sciences, e.g., macromolecular dynamics, astronomy, and classical

  5. 78 FR 23866 - Safety Zone; Crescent City 4th of July Fireworks; Crescent City Harbor, Crescent City, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-23

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Crescent City 4th of July Fireworks; Crescent City Harbor, Crescent City, CA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking... Crescent City, CA in support of the Crescent City 4th of July Fireworks on July 4, 2013. This safety...

  6. 78 FR 23869 - Safety Zone; Redwood City 4th of July Fireworks Show; Port of Redwood City, Redwood City, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-23

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Redwood City 4th of July Fireworks Show; Port of Redwood City, Redwood City, CA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking... of Redwood City near Redwood City, CA in support of the Redwood City 4th of July Fireworks Show...

  7. A high-order WENO-Z finite difference based particle-source-in-cell method for computation of particle-laden flows with shocks

    NASA Astrophysics Data System (ADS)

    Jacobs, Gustaaf B.; Don, Wai-Sun

    2009-03-01

    A high-order particle-source-in-cell (PSIC) algorithm is presented for the computation of the interaction between shocks, small scale structures, and liquid and/or solid particles in high-speed engineering applications. The improved high-order finite difference weighted essentially non-oscillatory (WENO-Z) method for solution of the hyperbolic conservation laws that govern the shocked carrier gas flow, lies at the heart of the algorithm. Finite sized particles are modeled as points and are traced in the Lagrangian frame. The physical coupling of particles in the Lagrangian frame and the gas in the Eulerian frame through momentum and energy exchange, is numerically treated through high-order interpolation and weighing. The centered high-order interpolation of the fluid properties to the particle location is shown to lead to numerical instability in shocked flow. An essentially non-oscillatory interpolation (ENO) scheme is devised for the coupling that improves stability. The ENO based algorithm is shown to be numerically stable and to accurately capture shocks, small flow features and particle dispersion. Both the carrier gas and the particles are updated in time without splitting with a third-order Runge-Kutta TVD method. One and two-dimensional computations of a shock moving into a particle cloud demonstrates the characteristics of the WENO-Z based PSIC method (PSIC/WENO-Z). The PSIC/WENO-Z computations are not only in excellent agreement with the numerical simulations with a third-order Rusanov based PSIC and physical experiments in [V. Boiko, V.P. Kiselev, S.P. Kiselev, A. Papyrin, S. Poplavsky, V. Fomin, Shock wave interaction with a cloud of particles, Shock Waves, 7 (1997) 275-285], but also show a significant improvement in the resolution of small scale structures. In two-dimensional simulations of the Mach 3 shock moving into forty thousand bronze particles arranged in the shape of a rectangle, the long time accuracy of the high-order method is demonstrated

  8. A high-order WENO-Z finite difference based particle-source-in-cell method for computation of particle-laden flows with shocks

    SciTech Connect

    Jacobs, Gustaaf B. Don, W.-S.

    2009-03-20

    A high-order particle-source-in-cell (PSIC) algorithm is presented for the computation of the interaction between shocks, small scale structures, and liquid and/or solid particles in high-speed engineering applications. The improved high-order finite difference weighted essentially non-oscillatory (WENO-Z) method for solution of the hyperbolic conservation laws that govern the shocked carrier gas flow, lies at the heart of the algorithm. Finite sized particles are modeled as points and are traced in the Lagrangian frame. The physical coupling of particles in the Lagrangian frame and the gas in the Eulerian frame through momentum and energy exchange, is numerically treated through high-order interpolation and weighing. The centered high-order interpolation of the fluid properties to the particle location is shown to lead to numerical instability in shocked flow. An essentially non-oscillatory interpolation (ENO) scheme is devised for the coupling that improves stability. The ENO based algorithm is shown to be numerically stable and to accurately capture shocks, small flow features and particle dispersion. Both the carrier gas and the particles are updated in time without splitting with a third-order Runge-Kutta TVD method. One and two-dimensional computations of a shock moving into a particle cloud demonstrates the characteristics of the WENO-Z based PSIC method (PSIC/WENO-Z). The PSIC/WENO-Z computations are not only in excellent agreement with the numerical simulations with a third-order Rusanov based PSIC and physical experiments in [V. Boiko, V.P. Kiselev, S.P. Kiselev, A. Papyrin, S. Poplavsky, V. Fomin, Shock wave interaction with a cloud of particles, Shock Waves, 7 (1997) 275-285], but also show a significant improvement in the resolution of small scale structures. In two-dimensional simulations of the Mach 3 shock moving into forty thousand bronze particles arranged in the shape of a rectangle, the long time accuracy of the high-order method is demonstrated

  9. Proceedings of the 4th International Conference and Exhibition: World Congress on Superconductivity, volume 1

    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.

  10. Proceedings of the 4th International Workshop on Tritium Effects in Plasma Facing Components

    SciTech Connect

    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.

  11. Proceedings of the 4th International Conference and Exhibition: World Congress on Superconductivity, Volume 2

    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.

  12. [Global Health. Information for change. 4th report of the Italian Observatory on Global Health].

    PubMed

    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.

  13. 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

  14. 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.

  15. Design of a Nb3Sn Magnet for a 4th Generation ECR Ion Source

    SciTech Connect

    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.

  16. Spiritual Health Scale 2011: Defining and Measuring 4th Dimension of Health

    PubMed Central

    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

  17. Simulation of two-phase liquid-vapor flows using a high-order compact finite-difference lattice Boltzmann method.

    PubMed

    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

  18. Simulation of two-phase liquid-vapor flows using a high-order compact finite-difference lattice Boltzmann method

    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

  19. [Giant cell tumor of the 4th metacarpal bone of the left hand. Apropos of a case].

    PubMed

    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.

  20. Corrigendum to "On the stability and diffusive characteristics of Roe-MUSCL and Runge-Kutta schemes for inviscid Taylor-Green vortex" [Journal of Computational Physics 299 (2015) 339-351

    NASA Astrophysics Data System (ADS)

    Bidadi, Shreyas; Rani, Sarma L.

    2016-01-01

    The authors regret that in Fig. 8(c) of the paper, the labels for the dimensionless time t* and flatness S4, as well as the plot legend are incorrect. In place of the original figure, the following figure should be used.

  1. [Analysis of the 4th generation outer space bred Angelica dahurica by FTIR spectroscopy].

    PubMed

    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.

  2. STO-2: Support for 4th Year Operations, Recovery, and Science ASU Co-I

    NASA Astrophysics Data System (ADS)

    Groppi, Christopher

    This is a Co-Investigator proposal for "STO-2: Support for 4th Year Operations, Recovery, and Science" with Prof. Christopher K. Walker (University of Arizona) as PI. As a participant in the STO-2 mission, ASU will participate in instrument design and construction, mission I&T, flight operations and data analysis. ASU has unique capabilities in the field of direct metal micromachining, which it will bring to bear on the STO-2 cold optical assembly, flight mixers and LO hardware. In addition, our extensive experience with receiver integration and test will supplement the capabilities of the PI institution during the I&T phase at the University of Arizona, CSBF (Palestine, TX) and in Antarctica. Both the ASU PI and student will also participate in data analysis and publication after the flight.

  3. 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.

  4. The 4th Bologna Winter School: Hot Topics in Structural Genomics

    PubMed Central

    2003-01-01

    The 4th Bologna Winter School on Biotechnologies was held on 9–15 February 2003 at the University of Bologna, Italy, with the specific aim of discussing recent developments in bioinformatics. The school provided an opportunity for students and scientists to debate current problems in computational biology and possible solutions. The course, co-supported (as last year) by the European Science Foundation program on Functional Genomics, focused mainly on hot topics in structural genomics, including recent CASP and CAPRI results, recent and promising genomewide predictions, protein–protein and protein–DNA interaction predictions and genome functional annotation. The topics were organized into four main sections (http://www.biocomp.unibo.it). PMID:18629078

  5. Beyond the genomics blueprint: the 4th Human Variome Project Meeting, UNESCO, Paris, 2012.

    PubMed

    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.

  6. Giant viruses in the oceans: the 4th Algal Virus Workshop.

    PubMed

    Claverie, Jean-Michel

    2005-06-20

    Giant double-stranded DNA viruses (such as record breaking Acanthamoeba polyphaga Mimivirus), with particle sizes of 0.2 to 0.6 microm, genomes of 300 kbp to 1.200 kbp, and commensurate complex gene contents, constitute an evolutionary mystery. They challenge the common vision of viruses, traditionally seen as highly streamlined genomes optimally fitted to the smallest possible--filterable--package. Such giant viruses are now discovered in increasing numbers through the systematic sampling of ocean waters as well as freshwater aquatic environments, where they play a significant role in controlling phyto- and bacterio- plankton populations. The 4th Algal Virus Workshop showed that the study of these ecologically important viruses is now massively entering the genomic era, promising a better understanding of their diversity and, hopefully, some insights on their origin and the evolutionary forces that shaped their genomes.

  7. 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.

  8. Food-based Science Curriculum Increases 4(th) Graders Multidisciplinary Science Knowledge.

    PubMed

    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.

  9. Food-based Science Curriculum Increases 4th Graders Multidisciplinary Science Knowledge

    PubMed Central

    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

  10. European Code against Cancer 4th Edition: Medical exposures, including hormone therapy, and cancer.

    PubMed

    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.

  11. Conditions for the generation of cytotoxic CD4+ Th cells that enhance CD8+ CTL-mediated tumor regression

    PubMed Central

    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

  12. EDITORIAL: Special issue containing papers presented at the 4th IAEA Technical Meeting on the Theory of Plasma Instabilities Special issue containing papers presented at the 4th IAEA Technical Meeting on the Theory of Plasma Instabilities

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Wilson, H. R.

    2010-05-01

    The 4th IAEA technical meeting (TM) on the Theory of Plasma Instabilities was held in Kyoto, May 18th--20th 2009, following the first (Seeon), second (Trieste) and third (York) meetings in this series. This IAEA-TM was motivated by the recent advances in theoretical methodology, the rapid progress in observations of laboratory and astrophysical plasmas and the evolution of fusion research as we approach the ITER era. The international advisory committee (IAC) and local organizing committee (LOC), the members of which are listed below, collaborated to define the scope and the content of the scientific programme. Young scientists were actively encouraged to participate in this TM to help stimulate their future research careers and raise their international profiles. Through these young scientists, the IAEA-TM planned to identify the future directions of research. About 90 researchers, from 13 countries and the IAEA, participated in this IAEA-TM, with 72 scientific presentations. The talks and posters generated enthusiastic discussions, contributing to the vibrancy of the meeting. This special issue of Nuclear Fusion consists of a cluster of papers, reporting some of the main contributions to the IAEA-TM. The articles in this cluster are representative of the scientific width of presentations at the meeting, spanning topics from micro-turbulence to large-scale MHD dynamics and from transport to detailed analysis of diagnostics. They demonstrate the quality and depth of the research presented at the conference. List of IAC (alphabetical order): B. Breizman (USA), S. Guenter (Germany), T. S. Hahm (USA), K. Itoh (Japan, Chair of 2009), Ya. I. Kolesnichenko (Ukraine), A. G. Peeters (UK), H. Wilson (UK) List of LOC (alphabetical order): A. Fukuyama, R. Horiuchi, S.-I. Itoh, N. Kasuya, Y. Kishimoto (co-chair), K. Kusano, J. Li, K. Mima, S. Murakami, H. Naitou, N. Nakajima, Y. Nakamura, H. Ohtani, S. Okamura, T. Ozeki, S. Sudo (co-chair), H. Sugama, Y. Todo, S. Tokuda, S

  13. [Level of smoking of 3rd and 4th grade students studying health and related factors: follow-up study].

    PubMed

    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.

  14. 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

  15. 4th annual primary care ethics conference: ethics education and lifelong learning

    PubMed Central

    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

  16. 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.

  17. The relationship between snack intake and its availability of 4th-6th graders in Taiwan.

    PubMed

    Hang, Chi-Ming; Lin, Wei; Yang, Hsiao-Chi; Pan, Wen-Harn

    2007-01-01

    The purpose of this study was to examine the relationship between the snack intake and snack availability of elementary school children. Data analyzed were from 722 4th to 6th graders' food availability and food intake questionnaires collected in the Nutrition and Health Survey in Taiwan Elementary School Children 2001-2002. The snacks commonly eaten were divided into two groups. Healthy snacks included dairy products, 100% fruit juice and fresh fruits. Unhealthy snacks included high fat/sugar snacks, cookies, candy, carbonated/sugared beverages and fast food. Structural equating modeling was used to test the models that describe the availability and intake of two snack groups. Results indicated that parents' intake and children's preference were major predictors of children intake of both healthy and unhealthy snacks. Other than that, the intake of unhealthy snacks was positively associated with "purchase by children themselves" but not the intake of healthy snacks, which was influenced predominantly by "present in home". The results support the perception that a positive family food environment is important for improving children's diet quality. To build a healthy family food environment, parents have to not only provide healthy snacks but also limit the unhealthy snacks in home. In addition to that, the role modeling of parents as eating healthy snacks instead of unhealthy snacks themselves may help children to develop similar behaviors.

  18. 4th-International Symposium on Ultrafast Surface Science - Final Report

    SciTech Connect

    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.

  19. Putting agent-based modeling to work: results of the 4th International Project Albert Workshop

    NASA Astrophysics Data System (ADS)

    Horne, Gary E.; Bjorkman, Eileen A.; Colton, Trevor

    2002-07-01

    Project Albert is an initiative of the US Marine Corps which uses a series of new models and tools, multidisciplinary teams, and the scientific method to explore questions of interest to military planners. Project Albert attempts to address key areas that traditional modeling and simulation techniques often do not capture satisfactorily and uses two data management concepts, data farming and data mining, to assist in identifying areas of interest. The current suite of models used by Project Albert includes four agent-based models that allow agents to interact with each other and produce emergent behaviors. The 4th International Project Albert Workshop was held 6-9 August 2001 in Australia. Workshop participants split into five groups, each of which attempted to apply various combinations of the Project Albert models to answer a series of questions in five areas: Control Operations; Reconnaissance, Surveillance, and Intelligence Force Mix; Precision Maneuver; Mission Area Analysis; and Peace Support Operations. This paper focuses on the methodology used during the workshop, the results of the workshop, and a summary of follow-on work since the workshop.

  20. European Code against Cancer 4th Edition: Ultraviolet radiation and cancer.

    PubMed

    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."

  1. CD4(+) Th2 cells are directly regulated by IL-10 during allergic airway inflammation.

    PubMed

    Coomes, S M; Kannan, Y; Pelly, V S; Entwistle, L J; Guidi, R; Perez-Lloret, J; Nikolov, N; Müller, W; Wilson, M S

    2017-01-01

    Interleukin-10 (IL-10) is an important regulatory cytokine required to control allergy and asthma. IL-10-mediated regulation of T cell-mediated responses was previously thought to occur indirectly via antigen-presenting cells. However, IL-10 can act directly on regulatory T cells and T helper type 17 (Th17) cells. In the context of allergy, it is therefore unclear whether IL-10 can directly regulate T helper type 2 (Th2) cells and whether this is an important regulatory axis during allergic responses. We sought to determine whether IL-10 signaling in CD4(+) Th2 cells was an important mechanism of immune regulation during airway allergy. We demonstrate that IL-10 directly limits Th2 cell differentiation and survival in vitro and in vivo. Ablation of IL-10 signaling in Th2 cells led to enhanced Th2 cell survival and exacerbated pulmonary inflammation in a murine model of house dust mite allergy. Mechanistically, IL-10R signaling regulated the expression of several genes in Th2 cells, including granzyme B. Indeed, IL-10 increased granzyme B expression in Th2 cells and led to increased Th2 cell death, identifying an IL-10-regulated granzyme B axis in Th2 cells controlling Th2 cell survival. This study provides clear evidence that IL-10 exerts direct effects on Th2 cells, regulating the survival of Th2 cells and severity of Th2-mediated allergic airway inflammation.

  2. 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.

  3. European Code against Cancer 4th Edition: 12 ways to reduce your cancer risk.

    PubMed

    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.

  4. 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).

  5. The Ratio of 2nd to 4th Digit Length in Korean Alcohol-dependent Patients

    PubMed Central

    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

  6. PREFACE: 4th International Conference on: Preservation and Conservation Issues in Digital Printing and Digital Photography

    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.

  7. PREFACE: 4th International Workshop on Statistical Physics and Mathematics for Complex Systems (SPMCS)

    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.

  8. 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.

  9. 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.

  10. 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

  11. Support for the 4th Pan-American Congress on Plants and Bioenergy

    SciTech Connect

    Carpita, Nicholas C.

    2016-01-25

    Intellectual Merit: Following the success of the first three Pan-American Congresses on Plants and BioEnergy held biennially, the 4th congress will be held at the University of Guelph, Canada June 4-7, 2014. We aim to continue a tradition of showcasing major advances in energy crop improvement yet keep in perspective the realities of the economic drivers and pressures that govern the translation of scientific success into a commercial success. The congress is endorsed by the American Society of Plant Biologists and the Canadian Society of Plant Biologists. The program will cover a range of disciplines, including algal and plant systems for bioenergy, plant genetics and genomics, gene discovery for improvement of bioenergy production and quality, regulatory mechanisms of synthesis and degradation, strategies for 3rd generation biofuel production and the promise of synthetic biology in production of biofuels and bio-based products, cropping systems and productivity for biomass production, and mitigation of environmental impacts of bioenergy production. Broader Impacts: We are requesting support to generate stipends for domestic and permanent-resident students, post-doctorals, and pre-tenured faculty members to attend and benefit from the outstanding program. The stipends will be limited to registration and on-site lodging costs, with partial support for travel in instances of great need. So that as great a number can benefit as possible, airfare costs will be provided for only applicants with great need. ASPB has endorsed this meeting and will assist in advertising and promoting the meeting. ASPB has a long-standing commitment to increase participation and advance the careers in plant biology of women, minorities and underrepresented scientists, and they will assist us in identifying worthy candidates.

  12. 75 FR 34369 - Safety Zones; City of Chicago's July 4th Celebration Fireworks, Lake Michigan, Chicago, IL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zones; City of Chicago's July 4th Celebration Fireworks, Lake Michigan, Chicago, IL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing two temporary safety zones on Lake Michigan near Chicago, Illinois....

  13. 75 FR 22330 - Safety Zone; City of Chicago's July 4th Celebration Fireworks, Lake Michigan, Chicago, IL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; City of Chicago's July 4th Celebration Fireworks, Lake Michigan, Chicago, IL AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard proposes to establish a safety zone on Lake Michigan near Chicago, Illinois....

  14. Communicating Science to Impact Learning? A Phenomenological Inquiry into 4th and 5th Graders' Perceptions of Science Information Sources

    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…

  15. Examining General and Specific Factors in the Dimensionality of Oral Language and Reading in 4th-10th Grades

    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…

  16. Comparative analysis of 1st, 2nd, and 4th year MD students' attitudes toward Complementary Alternative Medicine (CAM)

    PubMed Central

    Riccard, Christopher P; Skelton, Michele

    2008-01-01

    Background To identify and report the attitudes and beliefs of 1st, 2nd, and 4th year medical students toward complementary alternative medicine (CAM). Methods The previously validated and reliability tested CHBQ was administered to medical students attending the University of South Florida School of Medicine. Results Significant changes were found between both 1st (46.0 ± 7.7) and 4th (37.8 ± 15.7) year students and 2nd (48.3 ± 7.8) and 4th (37.8 ± 15.7) year students. No significant difference was found between 1st (46.0 ± 7.7) and 2nd (48.3 ± 7.8) year students. When comparing scores based on gender, a significant difference was present between males (41.2 ± 12.2) and females (46.1 ± 11.0). Conclusion CHBQ scores were significantly more positive in both 1st and 2nd year medical students in comparison with 4th year student's scores. These findings suggest that as student exposure to allopathic techniques and procedures increases during the last year of medical school, their attitudes toward CAM decrease. Females were also significantly more likely to have stronger positive attitudes toward CAM than males, though both genders represented an overall positive attitude toward CAM. PMID:18799010

  17. 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...

  18. Proceedings of the International Conference on Educational Data Mining (EDM) (4th, Eindhoven, the Netherlands, July 6-8, 2011)

    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…

  19. 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…

  20. 77 FR 39422 - Eighth Coast Guard District Annual Safety Zones; Niceville July 4th Fireworks Show; Boggy Bayou...

    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...

  1. 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…

  2. Analysis of Lexical Quality and Its Relation to Writing Quality for 4th Grade, Primary School Students in Chile

    ERIC Educational Resources Information Center

    Gómez Vera, Gabriela; Sotomayor, Carmen; Bedwell, Percy; Domínguez, Ana María; Jéldrez, Elvira

    2016-01-01

    Few studies have addressed vocabulary quality in developing writing skill in Spanish. Even less addressed it within the Chilean educational system. The specific objective of this study was to characterize, using a comprehensive set of indicators, the quality of the vocabulary produced by Chilean 4th grade students. Based on a national writing…

  3. Teacher Implementation of Reform-Based Mathematics and Implications for Algebra Readiness: A Qualitative Study of 4th Grade Classrooms

    ERIC Educational Resources Information Center

    Sher, Stephen Korb

    2011-01-01

    This study looked at 4th grade classrooms to see "how" teachers implement NCTM standards-based or reform-based mathematics instruction and then analyzed it for the capacity to improve students' "algebra readiness." The qualitative study was based on classroom observations, teacher and administrator interviews, and teacher surveys. The study took…

  4. 4th Annual SATN Conference 2011: Curriculum Transformation at Universities of Technology: Towards Development of New Generation Universities

    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…

  5. 4th Rare Disease South Eastern Europe (See) Meeting Skopje, Macedonia (November 14th, 2015).

    PubMed

    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

  6. 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

  7. 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

  8. Proceedings of the Biennial EO/EEO Research Symposium (4th) Held in Cocoa Beach, Florida on December 5-7, 2001

    DTIC Science & Technology

    2003-01-01

    PROCEEDINGS 4th Biennial EO/EEO Research Symposium December 5-7, 2001 Cocoa Beach, Florida Published January 2003 DEOMI Research Report 03-01...distribution unlimited 13. SUPPLEMENTARY NOTES Proceedings 4th Biennial EO/EEO Research Symposium, Held in Cocoa Beach, Florida on December 5-7...Prescribed by ANSI Std Z39-18 ii Proceedings 4th Biennial EO/EEO Research Symposium December 5-7, 2001 Cocoa Beach, Florida Sponsored

  9. 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.

  10. High Order Discontinuous Gelerkin Methods for Convection Dominated Problems with Application to Aeroacoustics

    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

  11. Exponential fitted Gauss, Radau and Lobatto methods of low order

    NASA Astrophysics Data System (ADS)

    Martín-Vaquero, J.; Vigo-Aguiar, J.

    2008-08-01

    Several exponential fitting Runge-Kutta methods of collocation type are derived as a generalization of the Gauss, Radau and Lobatto traditional methods of two steps. The new methods are capable of the exact integration (with only round-off errors) of differential equations whose solutions are linear combinations of an exponential and ordinary polynomials. Theorems of the truncation error reveal the good behavior of the new methods for stiff problems. Plots of their absolute stability regions that include the whole of the negative real axis are provided. A different procedure to find the parameter of the method is proposed. The variable step Radau method of two stages is derived. Finally, numerical examples underscore the efficiency of the proposed codes, especially when they are integrating stiff problems.

  12. A Brief Boot Camp for 4th-Year Medical Students Entering into Pediatric and Family Medicine Residencies

    PubMed Central

    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

  13. A Brief Boot Camp for 4th-Year Medical Students Entering into Pediatric and Family Medicine Residencies.

    PubMed

    Burns, Rebekah; Adler, Mark; Mangold, Karen; Trainor, Jennifer

    2016-02-09

    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 required for

  14. STO-2: Support for 4th Year Operations, Recovery, and Science (JPL co-I)

    NASA Astrophysics Data System (ADS)

    Kawamura, Jonathan

    Here we propose "STO-2: Support for 4th Year Operations, Recovery, and Science," a project being led by Dr. Christopher Walker of the University of Arizona. The Stratospheric TeraHertz Observatory was ready for its second Antarctic flight (STO-2) in the 2015-2016 austral summer. However, due to the late establishment of the stratospheric anti-cyclone and poor surface conditions, STO-2 was unable to launch. The decision was made to winter-over the STO-2 payload in its hangar for launch during the 2016-2017 Antarctic campaign. Funds to cover preparations and deployment of key members of the instrument team in support of the campaign are being provided by NASA under the existing grant. However, these funds are only sufficient to cover expenses up to December 31st, 2016. Here, we request resources for calendar year 2017 to support mission operations, payload recovery, and science operations. These elements will enable the team to deliver fully on STO-2's science mission, and maximize NASA's demonstrated investment in STO-2's success. STO-2 addresses a key problem in modern astrophysics: understanding the Life Cycle of the Interstellar Medium (ISM). STO-2 will survey approximately ˜ of the Southern Galactic Plane in the dominant interstellar cooling line [CII] (158 μm) and the important star formation tracer [NII] (205 μm). In addition, STO-2 will perform path finding observations of the 63 μm [OI] line toward selected regions. With 1 arcminute angular resolution, STO-2 will spatially resolve atomic, ionic and molecular clouds out to 10 kpc. The STO-2 survey will be conducted at unparalleled sensitivity levels. STO-2 will uniquely probe the pivotal formative and disruptive stages in the life cycle of interstellar clouds and the relationship between global star formation rates and the properties of the ISM. Combined with previous HI and CO surveys, STO-2 will create 3- dimensional maps of the structure, dynamics, turbulence, energy balance, and pressure of the Milky

  15. 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

  16. 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.

  17. Reliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.

    PubMed

    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.

  18. R&W Club Frederick Hosts 4th Annual Golf Tournament Benefiting The Children’s Inn at NIH | Poster

    Cancer.gov

    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.

  19. Working Group on Ice Forces (4th) State-of-the-Art Report Held in Iowa City, Iowa in 1986.

    DTIC Science & Technology

    1989-02-01

    OTTAWA OF CANADA CANADA HYDRAULICS LABORATORY Preface The following papers comprise the contributions to the 4 th State-of-the-Art Report on Ice Forces...in developing an understanding of ice interacting with offshore structures. : Odes iili/or AjA Jordaan and McKenna follow with a description of the...and Moore follow with a more detailed look at ice impact loads on ship hulls. This review is based on full scale trials of several icebreaking vessels

  20. 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.

  1. 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.

  2. A Parallel 3D Spectral Difference Method for Solutions of Compressible Navier Stokes Equations on Deforming Grids and Simulations of Vortex Induced Vibration

    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.

  3. 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.

  4. An efficient and accurate two-stage fourth-order gas-kinetic scheme for the Euler and Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Pan, Liang; Xu, Kun; Li, Qibing; Li, Jiequan

    2016-12-01

    For computational fluid dynamics (CFD), the generalized Riemann problem (GRP) solver and the second-order gas-kinetic scheme (GKS) provide a time-accurate flux function starting from a discontinuous piecewise linear flow distributions around a cell interface. With the adoption of time derivative of the flux function, a two-stage Lax-Wendroff-type (L-W for short) time stepping method has been recently proposed in the design of a fourth-order time accurate method for inviscid flow [21]. In this paper, based on the same time-stepping method and the second-order GKS flux function [42], a fourth-order gas-kinetic scheme is constructed for the Euler and Navier-Stokes (NS) equations. In comparison with the formal one-stage time-stepping third-order gas-kinetic solver [24], the current fourth-order method not only reduces the complexity of the flux function, but also improves the accuracy of the scheme. In terms of the computational cost, a two-dimensional third-order GKS flux function takes about six times of the computational time of a second-order GKS flux function. However, a fifth-order WENO reconstruction may take more than ten times of the computational cost of a second-order GKS flux function. Therefore, it is fully legitimate to develop a two-stage fourth order time accurate method (two reconstruction) instead of standard four stage fourth-order Runge-Kutta method (four reconstruction). Most importantly, the robustness of the fourth-order GKS is as good as the second-order one. In the current computational fluid dynamics (CFD) research, it is still a difficult problem to extend the higher-order Euler solver to the NS one due to the change of governing equations from hyperbolic to parabolic type and the initial interface discontinuity. This problem remains distinctively for the hypersonic viscous and heat conducting flow. The GKS is based on the kinetic equation with the hyperbolic transport and the relaxation source term. The time-dependent GKS flux function

  5. Numerical Investigation of Transition in Supersonic Boundary Layers Using DNS and LES

    DTIC Science & Technology

    2008-03-31

    order Runge - Kutta method for time- advancement and "fourth-order" split finite differences in the x- and y-directions. However, an analysis of the...34 1.3 Common Methods for Stability Investigations .... ............. 38 1.3.1 Linear Stability Theory ............................ 38 1.3.1.1 Inviscid...57 3. Numerical Method and Simulation Setup ................... 60 3.1 Initial Condition

  6. Modulation instability in nonlinear coupled resonator optical waveguides and photonic crystal waveguides.

    PubMed

    Huang, Chih-Hsien; Lai, Ying-Hsiuan; Cheng, Szu-Cheng; Hsieh, Wen-Feng

    2009-02-02

    Modulation instability (MI) in a coupled resonator optical waveguide (CROW) and photonic-crystal waveguide (PCW) with nonlinear Kerr media was studied by using the tight-binding theory. By considering the coupling between the defects, we obtained a discrete nonlinear evolution equation and termed it the extended discrete nonlinear Schrödinger (EDNLS) equation. By solving this equation for CROWs and PCWs, we obtained the MI region and the MI gains, G(p,q), for different wavevectors of the incident plane wave (p) and perturbation (q) analytically. In CROWs, the MI region, in which solitons can be formed, can only occur for pa being located either before or after pi/2, where a is the separation of the cavities. The location of the MI region is determined by the number of the separation rods between defects and the sign of the Kerr coefficient. However, in the PCWs, pa in the MI region can exceed the pi/2. For those wavevectors close to pi/2, the MI profile, G(q), can possess two gain maxima at fixed pa. It is quite different from the results of the nonlinear CROWs and optical fibers. By numerically solving the EDNLS equation using the 4th order Runge-Kutta method to observe exponential growth of small perturbation in the MI region, we found it is consistent with our analytic solutions.

  7. Solutions of the Taylor-Green Vortex Problem Using High-Resolution Explicit Finite Difference Methods

    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.

  8. 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.

  9. The interaction of turbulence with parallel and perpendicular shocks

    NASA Astrophysics Data System (ADS)

    Adhikari, L.; Zank, G. P.; Hunana, P.; Hu, Q.

    2016-11-01

    Interplanetary shocks exist in most astrophysical flows, and modify the properties of the background flow. We apply the Zank et al 2012 six coupled turbulence transport model equations to study the interaction of turbulence with parallel and perpendicular shock waves in the solar wind. We model the 1D structure of a stationary perpendicular or parallel shock wave using a hyperbolic tangent function and the Rankine-Hugoniot conditions. A reduced turbulence transport model (the 4-equation model) is applied to parallel and perpendicular shock waves, and solved using a 4th- order Runge Kutta method. We compare the model results with ACE spacecraft observations. We identify one quasi-parallel and one quasi-perpendicular event in the ACE spacecraft data sets, and compute various turbulent observed values such as the fluctuating magnetic and kinetic energy, the energy in forward and backward propagating modes, the total turbulent energy in the upstream and downstream of the shock. We also calculate the error associated with each turbulent observed value, and fit the observed values by a least square method and use a Fourier series fitting function. We find that the theoretical results are in reasonable agreement with observations. The energy in turbulent fluctuations is enhanced and the correlation length is approximately constant at the shock. Similarly, the normalized cross helicity increases across a perpendicular shock, and decreases across a parallel shock.

  10. 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.

  11. Development of a numerical approach to the theory of the rotation of the Moon: A study of latitudinal parameters physical libration.

    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.

  12. 3D Global Two-Fluid Simulations of Turbulence in LAPD

    NASA Astrophysics Data System (ADS)

    Fisher, Dustin; Rogers, Barrett; Ricci, Paolo

    2012-10-01

    3D global two-fluid simulations are presented in an ongoing effort to identify and understand the physics of instabilities that arise in the Large Plasma Device (LAPD) at UCLA's Basic Science Facility. The LAPD, with its wide range of tunable parameters and device configurations, is ideally suited for studying space and laboratory plasmas. Moreover, the highly detailed and reproducible measurements of the LAPD lend themselves amicably to comparisons with simulations. Ongoing modeling is done using a modified version of the Global Braginskii Solver (GBS) [1] that models the plasma from source to edge region in a fully 3D two-fluid code. The reduced Braginskii equations are solved on a field-aligned grid using a finite difference method and 4th order Runge-Kutta time stepping and are parallelized on Dartmouth's Discovery cluster. Recent progress has been made to account for the thermionic cathode emission of fast electrons at the source, the axial dependence of the plasma source, and it is now possible to vary the potential on the front and side walls. Preliminary results, seen from the density and temperature profiles, show that the low frequency Kelvin Helmholtz instability still dominates the turbulence in the device.[4pt] [1] B. Rogers and P. Ricci. Phys. Rev. Lett. 104:225002, 2010

  13. Nonlinear Ion Harmonics in the Paul Trap with Added Octopole Field: Theoretical Characterization and New Insight into Nonlinear Resonance Effect.

    PubMed

    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.

  14. MSFC Stream Model Preliminary Results: Modeling Recent Leonid and Perseid Encounters

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Moser, Danielle E.

    2004-01-01

    The cometary meteoroid ejection model of Jones and Brown (1996b) was used to simulate ejection from comets 55P/Tempel-Tuttle during the last 12 revolutions, and the last 9 apparitions of 109P/Swift-Tuttle. Using cometary ephemerides generated by the Jet Propulsion Laboratory s (JPL) HORIZONS Solar System Data and Ephemeris Computation Service, two independent ejection schemes were simulated. In the first case, ejection was simulated in 1 hour time steps along the comet s orbit while it was within 2.5 AU of the Sun. In the second case, ejection was simulated to occur at the hour the comet reached perihelion. A 4th order variable step-size Runge-Kutta integrator was then used to integrate meteoroid position and velocity forward in time, accounting for the effects of radiation pressure, Poynting-Robertson drag, and the gravitational forces of the planets, which were computed using JPL s DE406 planetary ephemerides. An impact parameter was computed for each particle approaching the Earth to create a flux profile, and the results compared to observations of the 1998 and 1999 Leonid showers, and the 1993 and 2004 Perseids.

  15. Screening in humid air plasmas

    NASA Astrophysics Data System (ADS)

    Filippov, Anatoly; Derbenev, Ivan; Dyatko, Nikolay; Kurkin, Sergey

    2016-09-01

    Low temperature air plasmas containing H2O molecules are of high importance for atmospheric phenomena, climate control, biomedical applications, surface processing, and purification of air and water. Humid air plasma created by an external ionization source is a good model of the troposphere where ions are produced by the galactic cosmic rays and decay products of air and soil radioactive elements such as Rn222. The present paper is devoted to study the ionic composition and the screening in an ionized humid air at atmospheric pressure and room temperature. The ionization rate is varied in the range of 101 -1018 cm-3s-1. The humid air with 0 - 1 . 5 % water admixture that corresponds to the relative humidity of 0 - 67 % at the air temperature equal to 20°C is considered. The ionic composition is determined on the analysis of more than a hundred processes. The system of 41 non-steady state particle number balance equations is solved using the 4th order Runge-Kutta method. The screening of dust particle charge in the ionized humid air are studied within the diffusion-drift approach. The screening constants are well approximated by the inverse Debye length and characteristic lengths of recombination and attachment processes. This work was supported by the Russian Science Foundation, Project No. 16-12-10424.

  16. An Interactive Microsoft(registered tm) Excel Program for Tracking a Single Evaporating Droplet in Crossflow

    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.

  17. 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.

  18. 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.

  19. 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.

  20. Peer Interaction During Collaborative Writing at the 4th/5th Grade Level.

    ERIC Educational Resources Information Center

    Nunn, Grace Gaeta

    A study was conducted to investigate oral language used in fourth- and fifth-grade student dyads in a collaborative writing setting in order to understand better how children learn to write. The study was based on a theoretical framework that emphasized the interrelatedness of thought, language, and learning. Following a pilot study, students in…

  1. Caldecott 4th bore tunnel project: influence of ground water flows and inflows triggered by tectonic fault zones?

    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

  2. Asymptotic solution for heat convection-radiation equation

    SciTech Connect

    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.

  3. Synapses as Therapeutic Targets for Autism Spectrum Disorders: An International Symposium Held in Pavia on July 4th, 2014

    PubMed Central

    Curatolo, Paolo; Ben-Ari, Yehezkel; Bozzi, Yuri; Catania, Maria Vincenza; D’Angelo, Egidio; Mapelli, Lisa; Oberman, Lindsay M.; Rosenmund, Christian; Cherubini, Enrico

    2014-01-01

    New progresses into the molecular and cellular mechanisms of autism spectrum disorders (ASDs) have been discussed in 1 day international symposium held in Pavia (Italy) on July 4th, 2014 entitled “synapses as therapeutic targets for autism spectrum disorders” (satellite of the FENS Forum for Neuroscience, Milan, 2014). In particular, world experts in the field have highlighted how animal models of ASDs have greatly advanced our understanding of the molecular pathways involved in synaptic dysfunction leading sometimes to “synaptic clinical trials” in children. PMID:25324723

  4. 4th Quarter Transportation Report FY 2014: Radioactive Waste Shipments to and from the Nevada National Security Site (NNSS)

    SciTech Connect

    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.

  5. Synapses as therapeutic targets for autism spectrum disorders: an international symposium held in pavia on july 4th, 2014.

    PubMed

    Curatolo, Paolo; Ben-Ari, Yehezkel; Bozzi, Yuri; Catania, Maria Vincenza; D'Angelo, Egidio; Mapelli, Lisa; Oberman, Lindsay M; Rosenmund, Christian; Cherubini, Enrico

    2014-01-01

    New progresses into the molecular and cellular mechanisms of autism spectrum disorders (ASDs) have been discussed in 1 day international symposium held in Pavia (Italy) on July 4th, 2014 entitled "synapses as therapeutic targets for autism spectrum disorders" (satellite of the FENS Forum for Neuroscience, Milan, 2014). In particular, world experts in the field have highlighted how animal models of ASDs have greatly advanced our understanding of the molecular pathways involved in synaptic dysfunction leading sometimes to "synaptic clinical trials" in children.

  6. JPRS Report, Science & Technology, Japan, 4th Intelligent Robots Symposium, Volume 2

    DTIC Science & Technology

    1989-03-16

    accidents caused by strikes by robots,5 a quantitative model for safety evaluation,6 and evaluations of actual systems7 in order to contribute to...Mobile Robot Position Referencing Using Map-Based Vision Systems.... 160 Safety Evaluation of Man-Robot System 171 Fuzzy Path Pattern of Automatic...camera are made after the robot stops to prevent damage from occurring through obstacle interference. The position of the camera is indicated on the

  7. Report on the 4'th scientific meeting of the "Verein zur Förderung des Wissenschaftlichen Nachwuchses in der Neurologie" (NEUROWIND e.V.) held in Motzen, Germany, Nov. 2'nd - Nov. 4'th, 2012.

    PubMed

    Linker, Ralf A; Meuth, Sven G; Magnus, Tim; Korn, Thomas; Kleinschnitz, Christoph

    2012-11-22

    From November 2nd - 4th 2012, the 4th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Again more than 60 participants, predominantly at the doctoral student or postdoc level, gathered to share their latest findings in the fields of neurovascular research, neurodegeneration and neuroinflammation. Like in the previous years, the symposium provided an excellent platform for scientific exchange and the presentation of innovative projects in the stimulating surroundings of the Brandenburg outback. This year's keynote lecture on the pathophysiological relevance of neuronal networks was given by Christian Gerloff, Head of the Department of Neurology at the University Clinic of Hamburg-Eppendorf. Another highlight of the meeting was the awarding of the NEUROWIND e.V. prize for young scientists working in the field of experimental neurology. The award is donated by the Merck Serono GmbH, Darmstadt, Germany and is endowed with 20.000 Euro. This year the jury decided unanimously to adjudge the award to Michael Gliem from the Department of Neurology at the University Clinic of Düsseldorf (group of Sebastian Jander), Germany, for his outstanding work on different macrophage subsets in the pathogenesis of ischemic stroke published in the Annals of Neurology in 2012.

  8. Idaho National Laboratory Quarterly Event Performance Analysis FY 2013 4th Quarter

    SciTech Connect

    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.

  9. Injector Beam Dynamics for a High-Repetition Rate 4th-Generation Light Source

    SciTech Connect

    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.

  10. Jacobi-Gauss-Lobatto collocation method for the numerical solution of 1+1 nonlinear Schrödinger equations

    NASA Astrophysics Data System (ADS)

    Doha, E. H.; Bhrawy, A. H.; Abdelkawy, M. A.; Van Gorder, Robert A.

    2014-03-01

    A Jacobi-Gauss-Lobatto collocation (J-GL-C) method, used in combination with the implicit Runge-Kutta method of fourth order, is proposed as a numerical algorithm for the approximation of solutions to nonlinear Schrödinger equations (NLSE) with initial-boundary data in 1+1 dimensions. Our procedure is implemented in two successive steps. In the first one, the J-GL-C is employed for approximating the functional dependence on the spatial variable, using (N-1) nodes of the Jacobi-Gauss-Lobatto interpolation which depends upon two general Jacobi parameters. The resulting equations together with the two-point boundary conditions induce a system of 2(N-1) first-order ordinary differential equations (ODEs) in time. In the second step, the implicit Runge-Kutta method of fourth order is applied to solve this temporal system. The proposed J-GL-C method, used in combination with the implicit Runge-Kutta method of fourth order, is employed to obtain highly accurate numerical approximations to four types of NLSE, including the attractive and repulsive NLSE and a Gross-Pitaevskii equation with space-periodic potential. The numerical results obtained by this algorithm have been compared with various exact solutions in order to demonstrate the accuracy and efficiency of the proposed method. Indeed, for relatively few nodes used, the absolute error in our numerical solutions is sufficiently small.

  11. An Integrated Experimental and Computational Study of Heating due to Surface Catalysis under Hypersonic Conditions

    DTIC Science & Technology

    2012-08-01

    Schemes (RDS), Spectral Finite Volume/Difference and standard Finite Element (FE). � explicit ( Runge Kutta n-order) and implicit (3 point-backward, Crank...Numerical method 21 2.1 Space discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.1.1 AUSM+ scheme...US3D code developed at the University of Minnesota in Prof. Graham Candlers research group has gained widespread use throughout NASA and U.S. Air

  12. Parallel Unsteady Overset Mesh Methodology for Adaptive and Moving Grids with Multiple Solvers

    DTIC Science & Technology

    2010-01-01

    Runge - Kutta time-stepping framework and is capable of up to fifth-order accurate spatial discretizations. Further, the Cartesian grids in the off-body are...no user intervention or explicit hole-map specification is necessary. The capabilities and performance of the package are presented for several test...connectivity approaches have been investigated in the past by various research groups . The prominent among them are PEGASUS5 [5], OVERFLOW-DCF [6, 7], SUGGAR

  13. Maneuvering in a Seaway

    DTIC Science & Technology

    2011-05-01

    forces are found from body-exact computations. The body-exact computations are all done in the time domain. Either a fourth-order Runge - Kutta scheme... method code that is computationally fast and can be used to predict ship maneuvering in a seaway. Technical Approach We are developing a blended... method to predict nonlinear ship motions while maneuvering in a seaway. The blended method uses the nonlinear Euler equations of motion and integrates

  14. Parallel Unsteady Overset Mesh Methodology for a Multi-Solver Paradigm with Adaptive Cartesian Grids

    DTIC Science & Technology

    2008-08-21

    a multi-stage Runge - Kutta time-stepping framework and is capable of up to fifth-order accurate spatial discretizations. Further, the Cartesian grids...cutting methodology such that no user inter- vention or explicit hole-map specification is necessary. The capabilities and performance of the package are...application to rotorcraft aerodynamics. Several Domain-Connectivity approaches have been investigated in the past by various research groups . The

  15. A Computational Model of the Eye for Primary and Secondary Blast Injury

    DTIC Science & Technology

    2012-10-01

    difference scheme [18] and integrated in time using a four-stage Runge - Kutta method . An eight-order implicit spatial filtering proposed by Gaintonde et...each 9 time step (Figure 4A). In general, there are two coupling methods used in fluid structure interaction algorithms— explicit (or weak, one... method . Prentice-Hall. Englewood Cliffs, NJ, Chapter 9. 25Zygote Media Group , Inc is a developer company for computer-generated 3D graphical

  16. Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

    DTIC Science & Technology

    2011-02-22

    ȳ. We use the fourth-order Runge - Kutta method with a constant step size to solve Eqs. (4.42) starting outside the boundary layer at ȳmax and...60 4.3.1 Governing equations . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 4.3.2 Numerical method ...equations and numerical method . . . . 66 4.4.1 Governing equations . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 4.4.2 Numerical method

  17. Distributed Autonomous Control of Multiple Spacecraft During Close Proximity Operations

    DTIC Science & Technology

    2007-12-01

    potential functions in its working area [6]. The APF is an intuitive geometric method of determining the behavior of groups of robots [58]. The...matched all model variations. Due to its commonality in both Simulink and STK, fourth order Runga- Kutta numerical integration method was used. Details... Runge - Kutta , and the Earth Gravitational model, such as EGM96 [36][32]. The HPOP command is of the general form, stkExec(ConID, ‘HPOP Path Parameter

  18. 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.

  19. Heat transfer in a micropolar fluid over a stretching sheet with Newtonian heating.

    PubMed

    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.

  20. Analytic streamline calculations on linear tetrahedra

    SciTech Connect

    Diachin, D.P.; Herzog, J.A.

    1997-06-01

    Analytic solutions for streamlines within tetrahedra are used to define operators that accurately and efficiently compute streamlines. The method presented here is based on linear interpolation, and therefore produces exact results for linear velocity fields. In addition, the method requires less computation than the forward Euler numerical method. Results are presented that compare accuracy measurements of the method with forward Euler and fourth order Runge-Kutta applied to both a linear and a nonlinear velocity field.

  1. Analytical and numerical validation for solving the fractional Klein-Gordon equation using the fractional complex transform and variational iteration methods

    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.

  2. An approximation technique for jet impingement flow

    SciTech Connect

    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.

  3. Multirate Time Integration for Compressible Atmospheric Flow

    SciTech Connect

    Wensch, Joerg; Galant, Alexander; Knoth, Oswald

    2008-09-01

    We generalise split-explicit Runge-Kutta methods utilised in atmospheric dynamics simulation where fast sub-processes (sound waves) are integrated by small time steps. The inclusion of fixed tendencies of previous stages leads to an improvement of the stability barrier for the acoustics equation by a factor of two. Order and stability analysis is based on the assumption of exact integration of fast subprocesses.

  4. Prescribing a multistage analytical method to a prey predator dynamical system

    NASA Astrophysics Data System (ADS)

    Goh, S. M.; Noorani, M. S. M.; Hashim, I.

    2008-12-01

    This article discusses the effectiveness of a fresh analytical method in solving a prey-predator problem, which is described as a system of two nonlinear ordinary differential equations. The method of interest is the multistage variational iteration method (MVIM), which provides a slight modification of the classical variational iteration method (VIM). We shall compare solutions of the classical VIM along with MVIM and match them against the conventional numerical method, Runge-Kutta (RK4) (fourth-order).

  5. Computer program for investigating effects of nonlinear suspension-system elastic properties on parachute inflation loads and motions

    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.

  6. A brief introduction to symplectic integrators and recent results

    SciTech Connect

    Channell, P.J.

    1994-02-01

    The author begins with a brief synopsis about Hamiltonian systems and symplectic maps. A symplectic integrator is a symplectic map {phi}(q,p;t) that systematically approximates the time t flow of a Hamiltonian system. Systematic means: (1) in time step, t, i.e. the error should vanish as some power of the time step, and (2) in order of approximation, i.e. one would like a hierarchy of such {phi} that have errors that vanish as successively higher powers of the time step. At present the authors known two general types of symplectic integrators: (1) implicit integrators that are derived from a generating function or from algebraic conditions on Runge-Kutta schemes, and (2) explicit integrators that are derived from integrable Hamiltonians or from algebraic conditions on Runge-Kutta schemes.

  7. Stress and Fracture Analyses Under Elastic-plastic and Creep Conditions: Some Basic Developments and Computational Approaches

    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.

  8. Seismically induced liquefaction structures in La Magdalena archaeological site, the 4th century AD Roman Complutum (Madrid, Spain)

    NASA Astrophysics Data System (ADS)

    Rodríguez-Pascua, M. A.; Silva, P. G.; Perucha, M. A.; Giner-Robles, J. L.; Heras, C.; Bastida, A. B.; Carrasco, P.; Roquero, E.; Lario, J.; Bardaji, T.; Pérez-López, R.; Elez, J.

    2016-10-01

    The ancient Roman city of Complutum (Alcalá de Henares, Madrid), founded in the 1st century AD, was one of the most important cities of Hispania. The old Roman city was destroyed, abruptly abandoned, relocated close by and rebuilt during the late 4th century AD. Destruction of the city and its relocation has not yet been explained by archaeologists. In this paper, with our multidisciplinary approach, we identify and characterize earthquake archaeological effects (EAEs) affecting the archaeological site, the La Magdalena, an agricultural holding 4 km from the core of Complutum. The most important EAEs in the site are liquefactions (sand dikes and explosive sand-gravel craters) affecting Roman structures, such as water tanks (cisterns), houses and graves. Ground liquefaction generated significant ground cracks, explosive craters and folds in foundations of buildings. Several other Roman sites throughout the valley were also abandoned abruptly during the 4th century AD, in some cases with EAEs of similar origin. This suggests the occurrence of a 5.0-6.6 Mw seismic event in the zone, in accordance with the minimum empirical limit of seismically-induced liquefaction and the maximum surface rupture length of the Henares fault.

  9. An Ecological Study of Food Desert Prevalence and 4th Grade Academic Achievement in New York State School Districts

    PubMed Central

    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

  10. Improved algorithm of ray tracing in ICF cryogenic targets

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Yang, Yongying; Ling, Tong; Jiang, Jiabin

    2016-10-01

    The high precision ray tracing inside inertial confinement fusion (ICF) cryogenic targets plays an important role in the reconstruction of the three-dimensional density distribution by algebraic reconstruction technique (ART) algorithm. The traditional Runge-Kutta methods, which is restricted by the precision of the grid division and the step size of ray tracing, cannot make an accurate calculation in the case of refractive index saltation. In this paper, we propose an improved algorithm of ray tracing based on the Runge-Kutta methods and Snell's law of refraction to achieve high tracing precision. On the boundary of refractive index, we apply Snell's law of refraction and contact point search algorithm to ensure accuracy of the simulation. Inside the cryogenic target, the combination of the Runge-Kutta methods and self-adaptive step algorithm are employed for computation. The original refractive index data, which is used to mesh the target, can be obtained by experimental measurement or priori refractive index distribution function. A finite differential method is performed to calculate the refractive index gradient of mesh nodes, and the distance weighted average interpolation methods is utilized to obtain refractive index and gradient of each point in space. In the simulation, we take ideal ICF target, Luneberg lens and Graded index rod as simulation model to calculate the spot diagram and wavefront map. Compared the simulation results to Zemax, it manifests that the improved algorithm of ray tracing based on the fourth-order Runge-Kutta methods and Snell's law of refraction exhibits high accuracy. The relative error of the spot diagram is 0.2%, and the peak-to-valley (PV) error and the root-mean-square (RMS) error of the wavefront map is less than λ/35 and λ/100, correspondingly.

  11. STO-2: Support for 4th Year Operations, Recovery, and Science: Smithsonian Astrophysical Observatory Co-I

    NASA Astrophysics Data System (ADS)

    Stark, Antony

    The Lead Proposal for this investigation originates from the University of Arizona, Steward Observatory under Principal Investigator Dr. Christopher K. Walker. The Smithsonian Astrophysical Observatory (SAO) is pleased to submit this subsidiary proposal for engineering and scientific collaboration on the reflight of the Stratospheric TeraHertz Observatory (STO-2). This proposal covers Support for 4th Year Operations, Recovery, and Science as a result of the failure to launch due to weather in the 2015-2016 season. The Institutional Principal Investigator for the SAO effort is Antony A. Stark, and scientific Co-Investigators Gary Melnick, Volker Tolls, and Matthew Ashby. SAO will provide pre-flight engineering and flight monitoring support for the second Long Duration Flight (LDF) from McMurdo Sound in Antarctica. Subsequent to the flight, SAO Co-Is will contribute to data management and analysis, scientific interpretation, publication of results, and public distribution of data.

  12. 4th Annual Conference for African-American Researchers in the Mathematical Sciences (CAARMS4). Preliminary Program

    SciTech Connect

    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.

  13. Medical Standby: An Experience at the 4(th) National Youth Camping and Motivation Program Organized by Maksak Malaysia.

    PubMed

    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.

  14. Macracanthorhynchus hirudinaceus Eggs in Canine Coprolite from the Sasanian Era in Iran (4th/5th Century CE)

    PubMed Central

    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

  15. Medical Standby: An Experience at the 4th National Youth Camping and Motivation Program Organized by Maksak Malaysia

    PubMed Central

    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

  16. Characterization of γ and γ' phases in 2nd and 4th generation single crystal nickel-base superalloys

    NASA Astrophysics Data System (ADS)

    Zietara, Maciej; Neumeier, Steffen; Göken, Mathias; Czyrska-Filemonowicz, Aleksandra

    2017-01-01

    A Ni based single crystal superalloy from the 2nd generation, PWA 1484, and one from the 4th generation, PWA 1497, were comparatively studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and nanoindentation technique in an atomic force microscope (NI-AFM) after high temperature creep deformation. During primary creep of both generations of superalloys, γ' precipitates start to coalesce and grow directionally. Further creep deformation leads to the topological inversion and coarsening of the rafted microstructure. The NI-AFM technique was used for measurements of the hardness of the γ and γ' phases in as-received and creep deformed samples in various conditions. The g matrix of the PWA 1497 superalloy is on average 0.8 GPa harder than that of PWA 1484 that can be explained by higher content of Re and Ru, since they partition predominantly to the matrix phase.

  17. [Report of the World Federation of Neurosurgical Societies (WFNS) international course and Cameroon Neurosurgery Society Congress (CNS) Yaoundé (Cameroon), 1st--4th October 2007].

    PubMed

    Eyenga, V C; Ndoumbe, A; Eloundou, N J

    2008-04-01

    Neurosurgery remains a very marginal activity in sub-Saharan Africa. In this part of the world which counts nearly 40 countries, some do not have a single neurosurgeon, some have one to five, the number of ten neurosurgeons per country remaining an exception! In its concern of popularizing and of developing neurosurgery worldwide, the WFNS organized an international course in Africa, October 2007 2nd-3rd in Yaoundé (Cameroon). The Cameroon Neurosurgery Society (CNS) took this opportunity to organize its very first congress in the presence of the WFNS delegation from October 1st to 4th, 2007. The joint meeting with the WFNS was baptized the "African Week of Neurosurgery". This special event was a first in sub-Saharan Africa. The delegation of the WFNS, led by Professor J. Brotchi (Belgium) President of the WFNS, was made up of Professors A. Sousa (Brazil), Mr. Choux (France), N. Tribolet (Swiss), M. Arraez (Spain), A. Bricolo (Italy), A. Kamlichi (Morocco), G. Dechambenoit (France), K. Kalangu (Zimbabwe). Twenty three neurosurgeons coming from nine African countries (Cameroon, Nigeria, Gabon, Congo, Niger, Burkina Faso, Ivory Coast, Senegal, and Guinea) took an active part in work. The scientific success of this event led to the creation of the "Association of Neurological Surgeons of Africa (ANSA)" which will be the WFNS-Africa interface in order to insure the development of neurosurgery in Africa.

  18. A low-cost RK time advancing strategy for energy-preserving turbulent simulations

    NASA Astrophysics Data System (ADS)

    Capuano, Francesco; Coppola, Gennaro; de Luca, Luigi; Balarac, Guillaume

    2014-11-01

    Energy-conserving numerical methods are widely employed in direct and large eddy simulation of turbulent flows. Semi-discrete conservation of energy is usually obtained by adopting the so-called skew-symmetric splitting of the non-linear term, defined as a suitable average of the divergence and advective forms. Although generally allowing global conservation of kinetic energy by convection, it has the drawback of being roughly twice as expensive as standard divergence or advective forms alone. A novel time-advancement strategy that retains the conservation properties of skew-symmetric-based schemes at a reduced computational cost has been developed in the framework of explicit Runge-Kutta schemes. It is found that optimal energy-conservation can be achieved by properly constructed Runge-Kutta methods in which only divergence and advective forms for the convective term are adopted. The new schemes can be considerably faster than skew-symmetric-based techniques. A general framework for the construction of optimized Runge-Kutta coefficients is developed, which has proven to be able to produce new methods with a specified order of accuracy on both solution and energy. The effectiveness of the method is demonstrated by numerical simulation of homogeneous isotropic turbulence.

  19. [A development of Byzantine Christian charities during the 4(th)-7(th) centuries and the birth of the hospital].

    PubMed

    Nam, Sung Hyun

    2015-04-01

    This study aims to examine the beginning and the development of Christian Charities during the 4(th)-6(th) centuries which would eventually result in the birth of the hospital in modern sense in the first half of the 7(th) century. For this purpose, I looked carefully into various primary sources concerning the early Christian institutions for the poor and the sick. Above all, it's proper to note that the first xenodocheion where hospitality was combined with a systematic caring, is concerned with the Trinitarian debate of the 4(th) century. In 356, Eustathios, one of the leaders of homoiousios group, established xenodocheion to care for the sick and the lepers in Sebaste of Armenia, whereas his opponent Aetios, doctor and leader of the heteroousios party, was reckoned to have combined the medical treatment with his clerical activities. Then, Basil of Caesarea, disciple of Eustathios of Sebaste, also founded in 372 a magnificent benevolent complex named 'Basileias' after its founder. I scrupulously analysed several contemporary materials mentioning the charitable institution of Caesarea which was called alternatively katagogia, ptochotropheion, xenodocheion. John Chrysostome also founded several nosokomeia in Constantinople at the end of the 4(th) century and the beginning of the 5(th) century. Apparently, the contemporary sources mention that doctors existed for these Charities, but there is no sufficient proof that these 'Christian Hospitals,' Basileias or nosokomeia of Constantinople were hospitals in modern sense. Imperial constitutions began to mention ptochotropheion, xenodocheion and orphanotropheion since the second half of the 5(th) century and then some Justinian laws evoked nosokomium, brephotrophia, gerontocomia. These laws reveal that 'Christian Hospitals' were well clarified and deeply rooted in Byzantine society already in these periods. And then, new benevolent institutions emerged in the 6(th) century: nosokomeia for a specific class and

  20. Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection.

    PubMed

    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.

  1. The St. Jude Cancer Education for Children Program Pilot Study: Determining the Knowledge Acquisition and Retention of 4th-Grade Students.

    PubMed

    Ayers, Katherine; Villalobos, Aubrey Van Kirk; Li, Zhenghong; Krasin, Matthew

    2016-03-01

    In 2006, St. Jude Children's Research Hospital began developing a school-based outreach program known as the St. Jude Cancer Education for Children Program (SJCECP). The program aimed to teach children about cancer and healthy habits that can prevent the formation of cancers into adulthood. During the 2010-2011 academic years, we conducted a pilot evaluation of the SJCECP curriculum, with the primary objective of evaluating the impact of the intervention on knowledge acquisition and retention among 4th-grade students participating in the program. Seven local schools and 481 students from the Memphis area participated in the program evaluation. The results of this study show that 4th-grade students are able to acquire gains in knowledge related to cells, cancer, and healthy living after receiving the SJCECP intervention. We conclude that the program can be a useful tool for improving knowledge of cancer concepts at the 4th-grade level.

  2. Quality of Education Predicts Performance on the Wide Range Achievement Test-4th Edition Word Reading Subtest

    PubMed Central

    Sayegh, Philip; Arentoft, Alyssa; Thaler, Nicholas S.; Dean, Andy C.; Thames, April D.

    2014-01-01

    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. PMID:25404004

  3. A study of personality factors and interaction in 4th-year dental students and their teachers.

    PubMed

    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.

  4. 4th International Meeting on Single Nucleotide Polymorphism and Complex Genome Analysis. Various uses for DNA variations.

    PubMed

    Brookes, Anthony J

    2002-02-01

    At the 4th International Meeting on Single Nucleotide Polymorphism and Complex Genome Analysis (Stockholm, Sweden, 10th-14th October 2001), approximately 100 scientists from more than 20 nations undertook a probing review of latest developments in the field. Despite impressive and still ongoing activities towards SNP discovery and validation, plus efforts towards haplotype exploitation, it was clear that supporting technologies for genotyping are way behind where they need to be. Innate complexity and large variances in aspects of genome function together pose immense challenges that are difficult to surmount in the human situation. In contrast, studies in simpler organisms and population/evolutionary genetics studies are yielding important new insights. Breakthroughs that are being made in understanding the genetic etiology of complex disease tend to involve genes of larger effect or extremely well merited candidates. Linkage studies and proximal phenotypes are being recommended, though the best way forward is still hotly debated. Consequently, many diverse and ambitious projects are underway, from which the data itself will eventually show what is and is not possible.

  5. Communicating Science to Impact Learning? A Phenomenological Inquiry into 4th and 5th Graders' Perceptions of Science Information Sources

    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.

  6. [Experience with percutaneous endoscopic gastrostomy in the nutrition of a patient with 3rd and 4th degree facial burns].

    PubMed

    Halmy, C; Szücs, A; Gyökeres, T; Dékány, K; Mezeine, T I; Kertész, E

    1998-05-17

    Recovery after thermal injury depends in great proportion on nutrition. A major problem is accounted in patients with facial burn, because they can not be nourished per vias naturales. Eliminating disadvantages of parenteral nutrition, but utilizing the advantages of enteral nutrition, we have tried a new method of treatment in a patient whose case is presented. On the second day after injury a percutaneous endoscopic gastrostomy was made. On the 7th day after injury and on the 4th day from the beginning of enteral nutrition complete intake of food and liquid was assured through the percutaneous endoscopic gastrostoma. We had no complication related to the gastrostoma. Nutrition through the percutaneous endoscopic gastrostoma at our patient provided a "natural" route to assure liquid, electrolite and energy balance, prevented atrophy of intestinal mucosa and its metabolic and immunologic complications. With the use of percutaneous endoscopic gastrostoma the possible complications of central line catheter were omitted. Our opinion is that percutaneous endoscopic gastrostomy is a safe and effective method for the clinical nutrition of burned patients.

  7. Development of partially-coherent wavefront propagation simulation methods for 3rd and 4th generation synchrotron radiation sources

    NASA Astrophysics Data System (ADS)

    Chubar, Oleg; Berman, Lonny; Chu, Yong S.; Fluerasu, Andrei; Hulbert, Steve; Idir, Mourad; Kaznatcheev, Konstantine; Shapiro, David; Shen, Qun; Baltser, Jana

    2011-09-01

    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.

  8. Identification of DRG-1 As a Melanoma-Associated Antigen Recognized by CD4+ Th1 Cells

    PubMed Central

    Kiniwa, Yukiko; Li, Jiang; Wang, Mingjun; Sun, Chuang; Lee, Jeffrey E.; Wang, Rong-Fu; Wang, Helen Y.

    2015-01-01

    Immunotherapy has emerged as a promising strategy for the treatment of metastatic melanoma. Clinical studies have demonstrated the feasibility of cancer immunotherapy using tumor antigens recognized by CD8+ T cells. However, the overall immune responses induced by these antigens are too weak and transient to induce tumor regression in the majority of patients who received immunization. A growing body of evidence suggests that CD4+ T helper (Th) cells play an important role in antitumor immunity. Therefore, the identification of MHC class II-restricted tumor antigens capable of stimulating CD4+ T cells may provide opportunities for developing effective cancer vaccines. To this end, we describe the identification of developmentally regulated GTP-binding protein 1 (DRG-1) as a melanoma-associated antigen recognized by HLA-DR11-restricted CD4+ Th1 cells. Epitope mapping analysis showed that the DRG1248-268 epitope of DRG-1 was required for T cell recognition. Reverse transcription-polymerase chain reaction revealed that DRG-1 was highly expressed in melanoma cell lines but not in normal tissues. DRG-1 knockdown by lentiviral-based shRNA suppressed melanoma cell proliferation and soft agar colony formation. Taken together, these data suggest that DRG-1 plays an important role in melanoma cell growth and transformation, indicating that DRG1 may represent a novel target for CD4+ T cell-mediated immunotherapy in melanoma. PMID:25993655

  9. A high-order relativistic two-fluid electrodynamic scheme with consistent reconstruction of electromagnetic fields and a multidimensional Riemann solver for electromagnetism

    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.

  10. NLSEmagic: Nonlinear Schrödinger equation multi-dimensional Matlab-based GPU-accelerated integrators using compact high-order schemes

    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

  11. Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Odontogenic and Maxillofacial Bone Tumors.

    PubMed

    Wright, John M; Vered, Marilena

    2017-03-01

    The 4th edition of the World Health Organization's Classification of Head and Neck Tumours was published in January of 2017. This article provides a summary of the changes to Chapter 4 Tumours of the oral cavity and mobile tongue and Chapter 8 Odontogenic and maxillofacial bone tumours. Odontogenic cysts which were eliminated from the 3rd 2005 edition were included in the 4th edition as well as other unique allied conditons of the jaws. Many new tumors published since 2005 have been included in the 2017 classification.

  12. Application of the FUN3D Unstructured-Grid Navier-Stokes Solver to the 4th AIAA Drag Prediction Workshop Cases

    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.

  13. Benefits of a 4th Ice Class in the Simulated Radar Reflectivities of Convective Systems Using a Bulk Microphysics Scheme

    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.

  14. Meeting Materials for the 4th NRC Meeting on the Guidance for and the Review of EPA's Toxicological Assessment of Inorganic Arsenic

    EPA Science Inventory

    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...

  15. The Attitude of the Students towards the Value of "Paying Attention to Being Healthy" in 4th Grade Elementary Social Sciences Course

    ERIC Educational Resources Information Center

    Tahiroglu, Mustafa; Cetin, Turhan

    2012-01-01

    This study was aimed to define the teaching of the value of "Paying Attention to Being Healthy" in 4th grade elementary Social Sciences course and to determine the students' attitude towards this value. To reach this goal, activities to teach the value of paying attention to being healthy were prepared and conducted. The effect of these…

  16. Autism: Proceedings of Annual Meeting of the National Society for Autistic Children (4th, June 22-24, 1972, Flint Michigan).

    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…

  17. The Effect of Direct Instruction Strategy on Math Achievement of Primary 4th and 5th Grade Students with Learning Difficulties

    ERIC Educational Resources Information Center

    Al-Makahleh, Ahmad Abdulhameed Aufan

    2011-01-01

    This study seeks to verify the effect of direct instruction strategy on Math achievment of students with learning difficulties in the fourth and fifth grade levels and measure the improvement in their attitudes to Mathematics. Sample consisted of sixty (60) students with Math learning difficulties attending 4th and 5th grade level resource rooms…

  18. U.S. Dietary and Physical Activity Guideline Knowledge and Corresponding Behaviors among 4th and 5th Grade Students: A Multi-Site Pilot Study

    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%;…

  19. The Effect of the Conceptual Change Oriented Instruction through Cooperative Learning on 4th Grade Students' Understanding of Earth and Sky Concepts

    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…

  20. Nation and Language: Modern Aspects of Socio-Linguistic Development. Proceedings of the 4th International Conference (Lithuania, October 21-22, 2010)

    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…

  1. The Relationship of Values in Elementary School 4th Grade Social Studies Textbook with the Attainments and Their Level of Being Included in Student Workbooks

    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…

  2. A study of infrasound propagation based on high-order finite difference solutions of the Navier-Stokes equations.

    PubMed

    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.

  3. PREFACE: 9th World Congress on Computational Mechanics and 4th Asian Pacific Congress on Computational Mechanics

    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

  4. Something going on in Milan: a review of the 4th International PhD Student Cancer Conference.

    PubMed

    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

  5. STO-2: Support for 4th Year Operations, Recovery, and Science JHU/APL Co-I

    NASA Astrophysics Data System (ADS)

    Bernasconi, Pietro

    This is a collaboration Co-I Institution proposal for the proposal "STO-2: Support for 4th Year Operations, Recovery, and Science" whose lead proposal is submitted by the University of Arizona with Dr. Christofer Walker as PI. STO-2 was flight-ready in the 2015-2016 austral summer. However, due to the late establishment of the stratospheric anti-cyclone and poor surface conditions, STO-2 was unable to launch. The decision was made to winter-over the STO-2 payload in its hangar for launch during the 2016-2017 Antarctic campaign. Funds to cover preparations and deployment of key members of the instrument team in support of the campaign are being provided by NASA under the existing grant. However, these funds are only sufficient to cover expenses up to approximately December 31st. Here we request supplemental funds to cover costs associated with STO-2 operations and recovery beyond this date. STO-2 will address a key problem in modern astrophysics, understanding the Life Cycle of the Interstellar Medium (ISM). STO-2 will survey approximately 1/4 of the Southern Galactic Plane in the dominant interstellar cooling line [CII] (158 μm) and the important star formation tracer [NII] (205 μm). In addition, STO-2 will perform path finding observations of the 63 μm [OI] line toward selected regions. With 1 arcminute angular resolution, STO-2 will spatially resolve atomic, ionic and molecular clouds out to 10 kpc. The STO-2 survey will be conducted at unparalleled sensitivity levels. STO-2 will uniquely probe the pivotal formative and disruptive stages in the life cycle of interstellar clouds and the relationship between global star formation rates and the properties of the ISM. Combined with previous HI and CO surveys, STO-2 will create 3-dimensional maps of the structure, dynamics, turbulence, energy balance, and pressure of the Milky Way's ISM, as well as the star formation rate. Once we gain an understanding of the relationship between ISM properties and star formation

  6. A global perspective for managing obesity and improving health: conventional treatment and surgical options: 4th Annual Obesity Summit, London, April 2016

    PubMed Central

    Ahmad, Adeel Nazir; Edwards, Kimberley L

    2016-01-01

    4th Annual Obesity Summit, London, 12–14 April 2016 There are more than 1.9 billion overweight people worldwide, culminating in high rates of Type 2 diabetes; and cardiovascular, digestive and other health problems. This makes obesity a startling phenomenon and a significant global health epidemic. To address this, The 2016 Obesity Summit, 4th in the series of obesity-related annual events organized by EuroSciCon, was held from 12 to 14 April 2016 at Cineworld, The O2 in London. This conference set the stage for three days of stimulating high-quality presentations on the advancements in obesity in an informal academic setting. Approximately 156 delegates including students, researchers, healthcare professionals and scientists from 36 countries around the world attended the event. This meeting report summarizes some of the most outstanding presentations. PMID:28116126

  7. A global perspective for managing obesity and improving health: conventional treatment and surgical options: 4th Annual Obesity Summit, London, April 2016.

    PubMed

    Ahmad, Adeel Nazir; Edwards, Kimberley L

    2016-12-01

    4th Annual Obesity Summit, London, 12-14 April 2016 There are more than 1.9 billion overweight people worldwide, culminating in high rates of Type 2 diabetes; and cardiovascular, digestive and other health problems. This makes obesity a startling phenomenon and a significant global health epidemic. To address this, The 2016 Obesity Summit, 4th in the series of obesity-related annual events organized by EuroSciCon, was held from 12 to 14 April 2016 at Cineworld, The O2 in London. This conference set the stage for three days of stimulating high-quality presentations on the advancements in obesity in an informal academic setting. Approximately 156 delegates including students, researchers, healthcare professionals and scientists from 36 countries around the world attended the event. This meeting report summarizes some of the most outstanding presentations.

  8. Biological Damage Threshold Induced by Ultrashort Fundamental, 2nd, and 4th Harmonic Light Pulses from a Mode-Locked Nd: Glass Laser.

    DTIC Science & Technology

    1980-12-01

    BY ULTRASHORT FUNDAMENTAL, 2ND, AND 4TH HARMONIC LIGHT PULSES 00 , FROM A MODE-LOCKED Nd:GLASS LASER C Adam P. Bruckner, Ph.D. J. Michael Schurr, Ph.D...Medicine, Aerospace Medical Division, AFSC, Brooks Air Force Base, Texas. Dr. Taboada (USAFSAM/RZL) was the Laboratory Project Scientist-in-Charge. When... TABOADA , Ph.D. /AONN E. PICKERING, M.S. Project Scientist Chief, Radiation Sciences Division ROY L. DEHART Colonel, USAF, MC Commander UNCLASSIFIED S

  9. Ovarian and adipose tissue dysfunction in polycystic ovary syndrome: report of the 4th special scientific meeting of the Androgen Excess and PCOS Society

    PubMed Central

    Yildiz, Bulent O.; Azziz, Ricardo

    2013-01-01

    Significant advances have been made in our understanding of ovarian dysfunction in polycystic ovary syndrome (PCOS), and alterations in adipose tissue function are likely to play an important role in its pathophysiology. This review highlights the principal novel concepts presented at the 4th special scientific meeting of the Androgen Excess and PCOS Society, “Ovarian and Adipose Tissue Dysfunction: Potential Roles in Polycystic Ovary Syndrome,” which occurred on June 6, 2008 in San Francisco, California. PMID:19394000

  10. Future perspectives in melanoma research : Meeting report from the "Melanoma Bridge". Napoli, December 1st-4th 2015.

    PubMed

    Ascierto, Paolo A; Agarwala, Sanjiv; Botti, Gerardo; Cesano, Alessandra; Ciliberto, Gennaro; Davies, Michael A; Demaria, Sandra; Dummer, Reinhard; Eggermont, Alexander M; Ferrone, Soldano; Fu, Yang Xin; Gajewski, Thomas F; Garbe, Claus; Huber, Veronica; Khleif, Samir; Krauthammer, Michael; Lo, Roger S; Masucci, Giuseppe; Palmieri, Giuseppe; Postow, Michael; Puzanov, Igor; Silk, Ann; Spranger, Stefani; Stroncek, David F; Tarhini, Ahmad; Taube, Janis M; Testori, Alessandro; Wang, Ena; Wargo, Jennifer A; Yee, Cassian; Zarour, Hassane; Zitvogel, Laurence; Fox, Bernard A; Mozzillo, Nicola; Marincola, Francesco M; Thurin, Magdalena

    2016-11-15

    The sixth "Melanoma Bridge Meeting" took place in Naples, Italy, December 1st-4th, 2015. The four sessions at this meeting were focused on: (1) molecular and immune advances; (2) combination therapies; (3) news in immunotherapy; and 4) tumor microenvironment and biomarkers. Recent advances in tumor biology and immunology has led to the development of new targeted and immunotherapeutic agents that prolong progression-free survival (PFS) and overall survival (OS) of cancer patients. Immunotherapies in particular have emerged as highly successful approaches to treat patients with cancer including melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), bladder cancer, and Hodgkin's disease. Specifically, many clinical successes have been using checkpoint receptor blockade, including T cell inhibitory receptors such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed cell death-1 (PD-1) and its ligand PD-L1. Despite demonstrated successes, responses to immunotherapy interventions occur only in a minority of patients. Attempts are being made to improve responses to immunotherapy by developing biomarkers. Optimizing biomarkers for immunotherapy could help properly select patients for treatment and help to monitor response, progression and resistance that are critical challenges for the immuno-oncology (IO) field. Importantly, biomarkers could help to design rational combination therapies. In addition, biomarkers may help to define mechanism of action of different agents, dose selection and to sequence drug combinations. However, biomarkers and assays development to guide cancer immunotherapy is highly challenging for several reasons: (i) multiplicity of immunotherapy agents with different mechanisms of action including immunotherapies that target activating and inhibitory T cell receptors (e.g., CTLA-4, PD-1, etc.); adoptive T cell therapies that include tissue infiltrating lymphocytes (TILs), chimeric antigen receptors (CARs), and

  11. Guest Editor's introduction: Selected papers from the 4th USENIX Conference on Object-Oriented Technologies and Systems

    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

  12. 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

  13. Dynamic predictive model for growth of Salmonella enteritidis in egg yolk.

    PubMed

    Gumudavelli, V; Subbiah, J; Thippareddi, H; Velugoti, P R; Froning, G

    2007-09-01

    Salmonella Enteritidis (SE) contamination of poultry eggs is a major human health concern worldwide. The risk of SE from shell eggs can be significantly reduced through rapid cooling of eggs after they are laid and their storage under safe temperature conditions. Predictive models for the growth of SE in egg yolk under varying ambient temperature conditions (dynamic) were developed. The growth of SE in egg yolk under several isothermal conditions (10, 15, 20, 25, 30, 35, 37, 39, 41, and 43 degrees C) was determined. The Baranyi model, a primary model, was fitted with growth data for each temperature and corresponding maximum specific growth rates were estimated. Root mean squared error (RMSE) values were less than 0.44 log10 CFU/g and pseudo-R2 values were greater than 0.98 for the primary model fitting. For developing the secondary model, the estimated maximum specific growth rates were then modeled as a function of temperature using the modified Ratkowsky's equation. The RMSE and pseudo-R2 were 0.05/h and 0.99, respectively. A dynamic model was developed by integrating the primary and secondary models and solving it numerically using the 4th-order Runge-Kutta method to predict the growth of SE in egg yolk under varying temperature conditions. The integrated dynamic model was then validated with 4 temperature profiles (varying) such as linear heating, exponential heating, exponential cooling, and sinusoidal temperatures. The predicted values agreed well with the observed growth data with RMSE values less than 0.29 log10 CFU/g. The developed dynamic model can predict the growth SE in egg yolk under varying temperature profiles.

  14. 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

  15. 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

  16. 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.

  17. Effect of olfactory and visual stimuli on the orientation of the 4th instar larvae of the stem borer Chilo partellus swinhoe (Lepidoptera: Pyralidae).

    PubMed

    Tokro, P G; Saxena, K N

    1991-01-01

    The orientational responses of 4th instar larvae of Chilo partellus to different sources of stimuli being artificial diet, leaves and stems of maize and sorghum were tested, under free choice and no-choice situations. Larvae were attracted to maize and sorghum in a moderate to high degree dependent on what choice they were given. The orientational preference of the larvae, offered a choice between the visual and the odour sources, depended upon their stimulating capacities which were represented by the percentages of individuals responding to the sources of stimuli. Odour played a greater role than visual stimuli in this close range attraction when the two competed with each other.

  18. [Tumors of the 4th ventricle and the craniospinal transitional zone. Review of patients of the Neurosurgical Clinic of the Department of Medicine of the Karl Marx University].

    PubMed

    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.

  19. Global challenges in the management of congenital cataract: proceedings of the 4th International Congenital Cataract Symposium held on March 7, 2014, New York, New York.

    PubMed

    Lenhart, Phoebe D; Courtright, Paul; Wilson, M Edward; Lewallen, Susan; Taylor, David Samuel; Ventura, Marcelo C; Bowman, Richard; Woodward, Lee; Ditta, Lauren C; Kruger, Stacey; Haddad, Danny; El Shakankiri, Nihal; Rai, Salma Kc; Bailey, Tehara; Lambert, Scott R

    2015-04-01

    Childhood cataracts have become a leading cause of preventable childhood blindness in many areas of the world. Here we summarize regional focus group discussions from the 4th Annual International Congenital Cataract Symposium on the current situation, challenges, and recommendations for the management of congenital cataracts in sub-Saharan Africa, the Middle East and North Africa, South Asia, Central America, South America, and developed nations. Strategies for managing congenital cataracts must be adapted and developed according to regional conditions. A basic framework for acceptable outcomes must focus on developing systems to address the critical components of education, access, quality care, and good follow-up.

  20. Ruggedized minicomputer hardware and software topics, 1981: Proceedings of the 4th ROLM MIL-SPEC Computer User's Group Conference

    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.

  1. Early LLNL Application Scaling Results on BlueGene/L

    SciTech Connect

    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).

  2. Essentially non-oscillatory shock capturing methods applied to turbulence amplification in shock wave calculations

    NASA Technical Reports Server (NTRS)

    Osher, Stanley; Shu, Chi-Wang

    1988-01-01

    ENO (essentially non-oscillatory) schemes can provide uniformly high order accuracy right up to discontinuities while keeping sharp, essentially non-oscillatory shock transitions. Recently, an efficient implementation of ENO schemes was obtained based on fluxes and TVD Runge-Kutta time discretizations. The resulting code is very simple to program for multi-dimensions. ENO schemes are especially suitable for computing problems with both discontinuities and fine structures in smooth regions, such as shock interaction with turbulence, for which results for 1-D and 2-D Euler equations are presented. Much better resolution is observed by using third order ENO schemes than by using second order TVD schemes for such problems.

  3. Humoral immunity and CD4+ Th1 cells are both necessary for a fully protective immune response upon secondary infection with Brucella melitensis.

    PubMed

    Vitry, Marie-Alice; Hanot Mambres, Delphine; De Trez, Carl; Akira, Shizuo; Ryffel, Bernhard; Letesson, Jean-Jacques; Muraille, Eric

    2014-04-15

    Brucella spp are intracellular bacteria that cause brucellosis, one of the most common zoonoses in the world. Given the serious medical consequences of this disease, a safe and effective human vaccine is urgently needed. Efforts to develop this vaccine have been hampered by our lack of understanding of what constitutes a protective memory response against Brucella. In this study, we characterize the cells and signaling pathways implicated in the generation of a protective immune memory response following priming by the injection of heat-killed or live Brucella melitensis 16M. Using a panel of gene-deficient mice, we demonstrated that during a secondary recall response, both the Brucella-specific humoral response and CD4+ Th1 cells must act together to confer protective immunity in the spleen to B. melitensis infection. Humoral protective immunity is induced by the inoculation of both heat-killed and live bacteria, and its development does not require T cells, MyD88/IL-12p35 signaling pathways, or an activation-induced deaminase-mediated isotype switch. In striking contrast, the presence of memory IFN-γ-producing CD4+ Th1 cells requires the administration of live bacteria and functional MyD88/IL-12p35 pathways. In summary, our work identifies several immune markers closely associated with protective immune memory and could help to define a rational strategy to obtain an effective human vaccine against brucellosis.

  4. Results of the 4th scientific workshop of the ECCO (I): pathophysiology of intestinal fibrosis in IBD.

    PubMed

    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.

  5. [Management of aspergillosis in immunocompromised patients. Recommendations of Lille University Hospital--4th version--November 2004].

    PubMed

    Alfandari, S; Leroy, O; de Botton, S; Yakoub-Agha, I; Durand-Joly, I; Leroy-Cotteau, A; Beaucaire, G

    2005-03-01

    Invasive aspergillosis is a severe complication in immunocompromised patients. The arrival of new antifungal agents motivated the redaction of guidelines, regularly updated, by a Lille University hospital multidisciplinary task force. These guidelines assess diagnostic and therapeutic issues. The main recommended diagnosis tool is the chest CT scan, ordered at the smallest suspicion and, also, measure of the blood and broncho alveolar lavage fluid galactomannan. Treatment guidelines assess prophylaxis, empirical and documented therapy. Primary prophylaxis is warranted in only two cases, pulmonary graft or stem cell transplant in patients with chronic GVH and receiving corticosteroids. Empirical therapy should use one of the available amphotericin B formulations, chosen according to the patient history. Caspofungin is another choice. Documented therapy, depending on presentation, can be a single drug or a combination. First line therapy for single drug is i.v. voriconazole. Lipid formulations of amphotericin B are another choice. A combination therapy can be used as a first line treatment, for multiple lesions, or as salvage therapy. It must include caspofungin, associated with liposomal amphotericin B or voriconazole. A tight cooperation with thoracic surgeons is recommended.

  6. RAM: a Relativistic Adaptive Mesh Refinement Hydrodynamics Code

    SciTech Connect

    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.

  7. 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.

  8. 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.

  9. Accuracy of schemes for the Euler equations with non-uniform meshes

    NASA Technical Reports Server (NTRS)

    Turkel, E.; Yaniv, S.; Landau, U.

    1985-01-01

    The effect of non-uniform grids on the solution of the Euler equations is analyzed. A Runge-Kutta type scheme based on a finite volume formulation is considered. It is shown that for arbitrary grids the scheme can be inconsistent even though it is second-order accurate for uniform grids. An improvement is suggested which leads to at least first-order accuracy for general grids. Test cases are presented in both two- and three-space dimensions. Applications to finite difference and implicit algorithms are also given.

  10. Accuracy of schemes for the Euler equations with non-uniform meshers

    NASA Technical Reports Server (NTRS)

    Turkel, E.; Yaniv, S.; Landau, U.

    1986-01-01

    The effect of nonuniform grids on the solution of the Euler equations is analyzed. A Runge-Kutta type scheme is considered based on a finite volume formuation. It is shown that for arbitrary grids the scheme can be inconsistent even though it is second-order accurate for uniform grids. An improvement is suggested which leads to at least first-order accuracy for general grids. Test cases are pesented in both two- and three-space dimensions. Applications to finite difference and impicit algorithms are also given.

  11. Symplectic and multisymplectic Lobatto methods for the ``good'' Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Aydın, A.; Karasözen, B.

    2008-08-01

    In this paper, we construct second order symplectic and multisymplectic integrators for the "good" Boussineq equation using the two-stage Lobatto IIIA-IIIB partitioned Runge-Kutta method, which yield an explicit scheme and is equivalent to the classical central difference approximation to the second order spatial derivative. Numerical dispersion properties and the stability of both integrators are investigated. Numerical results for different solitary wave solutions confirm the excellent long time behavior of symplectic and multisymplectic integrators by preserving local and global energy and momentum.

  12. Accuracy of schemes with nonuniform meshes for compressible fluid flows

    NASA Technical Reports Server (NTRS)

    Turkel, E.

    1985-01-01

    The accuracy of the space discretization for time-dependent problems when a nonuniform mesh is used is considered. Many schemes reduce to first-order accuracy while a popular finite volume scheme is even inconsistent for general grids. This accuracy is based on physical variables. However, when accuracy is measured in computational variables then second-order accuracy can be obtained. This is meaningful only if the mesh accurately reflects the properties of the solution. In addition, the stability properties of some improved accurate schemes are analyzed and it can be shown that they also allow for larger time steps when Runge-Kutta type methods are used to advance in time.

  13. 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.

  14. 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.

  15. 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.

  16. A unified discontinuous Galerkin framework for time integration.

    PubMed

    Zhao, Shan; Wei, G W

    2014-05-15

    We introduce a new discontinuous Galerkin approach for time integration. On the basis of the method of weighted residual, numerical quadratures are employed in the finite element time discretization to account for general nonlinear ordinary differential equations. Many different conditions, including explicit, implicit, and symplectic conditions, are enforced for the test functions in the variational analysis to obtain desirable features of the resulting time-stepping scheme. The proposed discontinuous Galerkin approach provides a unified framework to derive various time-stepping schemes, such as low-order one-step methods, Runge-Kutta methods, and multistep methods. On the basis of the proposed framework, several explicit Runge-Kutta methods of different orders are constructed. The derivation of symplectic Runge-Kutta methods has also been realized. The proposed framework allows the optimization of new schemes in terms of several characteristics, such as accuracy, sparseness, and stability. The accuracy optimization is performed on the basis of an analytical form of the error estimation function for a linear test initial value problem. Schemes with higher formal order of accuracy are found to provide more accurate solutions. We have also explored the optimization potential of sparseness, which is related to the general compressive sensing in signal/imaging processing. Two critical dimensions of the stability region, that is, maximal intervals along the imaginary and negative real axes, are employed as the criteria for stability optimization. This gives the largest Courant-Friedrichs-Lewy time steps in solving hyperbolic and parabolic partial differential equations, respectively. Numerical experiments are conducted to validate the optimized time-stepping schemes.

  17. Climatic changes and social transformations in the Near East and North Africa during the 'long' 4th millennium BC: A comparative study of environmental and archaeological evidence

    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

  18. High-Order CESE Methods for Solving Hyperbolic PDEs (Preprint)

    DTIC Science & Technology

    2011-05-03

    DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER High-Order CESE Methods for Solving Hyperbolic PDEs (Preprint) 5b. GRANT NUMBER...continuous mesh refinement. The new high-order CESE method shares many favorable attributes of the original second-order CESE method, including: (i...Fluid Dynamics CESE ˙4th International Journal of Computational Fluid Dynamics Vol. 00, No. 00, Month 2009, 1–19 RESEARCH ARTICLE High-Order CESE

  19. Comparison of the Richmond HRR 4th edition and Farnsworth-Munsell 100 Hue Test for quantitative assessment of tritan color deficiencies.

    PubMed

    Foote, Katharina G; Neitz, Maureen; Neitz, Jay

    2014-04-01

    Drugs and environmental factors can induce tritan deficiencies. The Farnsworth-Munsell (FM) 100 Hue Test has become the gold standard in measuring these acquired defects. However, the test is time consuming, and color discrimination is confounded by concentration and patience. Here, we describe a test that compares six tritan plates from the HRR Pseudoisochromatic Plates 4th edition to 16 FM 100 Hue tritan caps. CIE Standard Illuminant C was reduced over five light intensities to simulate the effects of acquired losses in the S-cone pathway. Both tests showed quantitative differences in error rates with all light levels; thus they could serve equally well for assessing acquired deficiencies. However, compared to the FM 100, the HRR took subjects about 20-40 s per trial, making it more practical.

  20. THE 4th SCHIZOPHRENIA INTERNATIONAL RESEARCH SOCIETY CONFERENCE, 5–9 APRIL 2014, FLORENCE, ITALY: A summary of topics and trends

    PubMed Central

    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

  1. Limbic system development underlies the emergence of classical fear conditioning during the 3rd and 4th weeks of life in the rat

    PubMed Central

    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

  2. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates

    PubMed Central

    Kovalev, S.; Green, B.; Golz, T.; Maehrlein, S.; Stojanovic, N.; Fisher, A. S.; Kampfrath, T.; Gensch, M.

    2017-01-01

    Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systems and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession. PMID:28382317

  3. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates.

    PubMed

    Kovalev, S; Green, B; Golz, T; Maehrlein, S; Stojanovic, N; Fisher, A S; Kampfrath, T; Gensch, M

    2017-03-01

    Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systems and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.

  4. Nonlinear dynamics of plasma oscillations modeled by an anharmonic oscillator

    SciTech Connect

    Enjieu Kadji, H. G.; Nana Nbendjo, B. R.; Chabi Orou, J. B.; Talla, P. K.

    2008-03-15

    This paper considers nonlinear dynamics of plasma oscillations modeled by an anharmonic oscillator. These plasma oscillations are described by a nonlinear differential equation of the form xe+{epsilon}(1+x{sup 2})x+x+{kappa}x{sup 2}+{delta}x{sup 3}=F cos {omega}t. The amplitudes of the forced harmonic, superharmonic, and subharmonic oscillatory states are obtained using the harmonic balance technique and the multiple time scales method. Admissible values of the amplitude of the external strength are derived. Bifurcation sequences displayed by the model for each type of oscillatory states are performed numerically through the fourth-order Runge-Kutta scheme.

  5. Irreversibility analysis of hydromagnetic flow of couple stress fluid with radiative heat in a channel filled with a porous medium

    NASA Astrophysics Data System (ADS)

    Eegunjobi, A. S.; Makinde, O. D.

    Numerical analysis of the intrinsic irreversibility of a mixed convection hydromagnetic flow of an electrically conducting couple stress fluid through upright channel filled with a saturated porous medium and radiative heat transfer was carried out. The thermodynamics first and second laws were employed to examine the problem. We obtained the dimensionless nonlinear differential equations and solves numerically with shooting procedure joined with a fourth order Runge-Kutta-Fehlberg integration scheme. The temperature and velocity obtained, used to analyse the entropy generation rate together with some various physical parameters of the flow. Our results are presented graphically and talk over.

  6. 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.

  7. 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.

  8. Tables for Supersonic Flow of Helium Around Right Circular Cones at Zero Angle of Attack

    NASA Technical Reports Server (NTRS)

    Sims, J. L.

    1973-01-01

    The results of the calculation of supersonic flow of helium about right circular cones at zero angle of attack are presented in tabular form. The calculations were performed using the Taylor-Maccoll theory. Numerical integrations were performed using a Runge-Kutta method for second-order differential equations. Results were obtained for cone angles from 2.5 to 30 degrees in regular increments of 2.5 degrees. In all calculations the desired free-stream Mach number was obtained to five or more significant figures.

  9. Modeling of heat transfer in a rotary kiln thermal desorder for removal of petroleum from soils

    SciTech Connect

    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.

  10. Lie symmetry analysis of a double-diffusive free convective slip flow with a convective boundary condition past a radiating vertical surface embedded in a porous medium

    NASA Astrophysics Data System (ADS)

    Afify, A. A.; Uddin, Md. J.

    2016-09-01

    A numerical study of a steady two-dimensional double-diffusive free convection boundary layer flow over a vertical surface embedded in a porous medium with slip flow and convective boundary conditions, heat generation/absorption, and solar radiation effects is performed. A scaling group of transformations is used to obtain the governing boundary layer equations and the boundary conditions. The transformed equations are then solved by the fourth- and fifth-order Runge-Kutta-Fehlberg numerical method with Maple 13. The results for the velocity, temperature, and concentration profiles, as well as the skin friction coefficient, the Nusselt number, and the Sherwood number are presented and discussed.

  11. Application of Modified Chebyshev Picard Iteration to Differential Correction for Improved Robustness and Computation Time

    NASA Astrophysics Data System (ADS)

    Swenson, Travis; Woollands, Robyn; Junkins, John; Lo, Martin

    2017-01-01

    A novel application of Modified Chebyshev Picard Iteration (MCPI) to differential correction is presented. By leveraging the Chebyshev basis functions of MCPI, interpolation in 1 dimension may be used to target plane crossing events, instead of integrating the 42 dimensional variational equation required for standard step integrators. This results in dramatically improved performance over traditional differential correctors. MCPI was tested against the Runge-Kutta 7/8 integrator on over 45,000 halo orbits in three different three-body problems, and was found to be up to an order of magnitude faster, while simultaneously increasing robustness.

  12. Unsteady hydromagnetic flow of dusty fluid and heat transfer over a vertical stretching sheet with thermal radiation

    SciTech Connect

    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.

  13. Speeding up Newton-type iterations for stiff problems

    NASA Astrophysics Data System (ADS)

    Gonzalez-Pinto, S.; Rojas-Bello, R.

    2005-09-01

    Iterative schemes based on the Cooper and Butcher iteration [5] are considered, in order to implement highly implicit Runge-Kutta methods on stiff problems. By introducing two appropriate parameters in the scheme, a new iteration making use of the last two iterates, is proposed. Specific schemes of this type for the Gauss, Radau IA-IIA and Lobatto IIIA-B-C processes are developed. It is also shown that in many situations the new iteration presents a faster convergence than the original.

  14. Undergraduate research report

    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.

  15. Improved numerical approach for the time-independent Gross-Pitaevskii nonlinear Schrödinger equation.

    PubMed

    Gammal, A; Frederico, T; Tomio, L

    1999-08-01

    In the present work, we improve a numerical method, developed to solve the Gross-Pitaevkii nonlinear Schrödinger equation. A particular scaling is used in the equation, which permits us to evaluate the wave-function normalization after the numerical solution. We have a two-point boundary value problem, where the second point is taken at infinity. The differential equation is solved using the shooting method and Runge-Kutta integration method, requiring that the asymptotic constants, for the function and its derivative, be equal for large distances. In order to obtain fast convergence, the secant method is used.

  16. A Video-Based Experimental Investigation of Wing Rock

    DTIC Science & Technology

    1989-08-01

    model and a fourth order Runge- Kutta integration. In the water tunnel tests, conducted at a = 35 °• and Reynolds numbers from 3-f-l/ft to 7-5 x 1f0...4 /ft, the movement of the leading-edge vortices and the model motion were * simultaneously tracked and analyzed using a video-based motion analysis...track and analyze the movement of leading-edge vortices and model motion. Wing rock is caused by the dynamic behavior of the leading-edge vortices

  17. Numerical Solution of Boundary Layer MHD Flow with Viscous Dissipation

    PubMed Central

    Mishra, S. R.; Jena, S.

    2014-01-01

    The present paper deals with a steady two-dimensional laminar flow of a viscous incompressible electrically conducting fluid over a shrinking sheet in the presence of uniform transverse magnetic field with viscous dissipation. Using suitable similarity transformations the governing partial differential equations are transformed into ordinary differential equations and then solved numerically by fourth-order Runge-Kutta method with shooting technique. Results for velocity and temperature profiles for different values of the governing parameters have been discussed in detail with graphical representation. The numerical evaluation of skin friction and Nusselt number are also given in this paper. PMID:24672367

  18. 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.

  19. Theoretical Studies of a Transient Stimulated Raman Amplifier

    DTIC Science & Technology

    1988-04-19

    Another concern is reducing memory requirements. For this reason, we settled on a mid-step Euler approach, rather than a fourth order Runge-Kutta...The semi-spectral approach with a mid-step Euler advancement in z is extremely robust. As long as sufficient spectral band- width is provided through a...the mid-step Euler method, 0 and timing routines. *. The variables NT and NY set the number of nodes in the t and y directions. These should be set

  20. Model for flow of Casson nanofluid past a non-linearly stretching sheet considering magnetic field effects

    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.

  1. Accelerated GPU simulation of compressible flow by the discontinuous evolution Galerkin method

    NASA Astrophysics Data System (ADS)

    Block, B. J.; Lukáčová-Medvid'ová, M.; Virnau, P.; Yelash, L.

    2012-08-01

    The aim of the present paper is to report on our recent results for GPU accelerated simulations of compressible flows. For numerical simulation the adaptive discontinuous Galerkin method with the multidimensional bicharacteristic based evolution Galerkin operator has been used. For time discretization we have applied the explicit third order Runge-Kutta method. Evaluation of the genuinely multidimensional evolution operator has been accelerated using the GPU implementation. We have obtained a speedup up to 30 (in comparison to a single CPU core) for the calculation of the evolution Galerkin operator on a typical discretization mesh consisting of 16384 mesh cells.

  2. Evolution de configurations de tourbillons avec les mêmes invariants globaux

    NASA Astrophysics Data System (ADS)

    Bécu, Emilie; Pavlov, Vadim

    2004-10-01

    In this Note, we address the question of the evolution of a distribution of N identical localized vortices. Using direct numerical simulation, (here the Runge-Kutta scheme of order 4), together with the localized-vortices model, we show that different initial distributions of vorticity with identical integral invariants may exist. We show that the initial configurations with the same invariants may evolve to totally different quasi-final states. To cite this article: E. Bécu, V. Pavlov, C. R. Mecanique 332 (2004).

  3. 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.

  4. The 4th R: Reasoning.

    ERIC Educational Resources Information Center

    Miles, Curtis

    1983-01-01

    Reviews sources of information on materials for teaching reasoning with a microcomputer. Suggests microcomputer magazines, catalogs of commercial materials, CONDUIT (a nonprofit organization devoted to educational computer use), and local microcomputer users groups. Lists Apple II software for strategy games with reasoning applications. (DMM)

  5. Modern Physics, 4th edition

    NASA Astrophysics Data System (ADS)

    Tipler, Paul A.; Llewellyn, Ralph

    The new edition of the classic text for the intermediate-level modern physics course, revised and updated to take students to the forefront of contemporary research and applications across the full spectrum of science and technology."

  6. Installation Contracting Course (4th)

    DTIC Science & Technology

    1991-09-27

    increasingly having to cope with the presence of endangered species (e.g., the desert tortoise at Fort Irwin and the red cockaded woodpecker at Fort Bragg). 3...the ears." Robert Burton Anatomy of Melancholy "Democritus to the Reader" I. INTRODUCTION. A. References. 1. FAR SUBPART 33.2; DFARS 33.232; AFARS

  7. A Kinesthetic Learning Approach to Earth Science for 3rd and 4th Grade Students on the Pajarito Plateau, Los Alamos, NM

    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

  8. European guidelines for empirical antibacterial therapy for febrile neutropenic patients in the era of growing resistance: summary of the 2011 4th European Conference on Infections in Leukemia.

    PubMed

    Averbuch, Diana; Orasch, Christina; Cordonnier, Catherine; Livermore, David M; Mikulska, Malgorzata; Viscoli, Claudio; Gyssens, Inge C; Kern, Winfried V; Klyasova, Galina; Marchetti, Oscar; Engelhard, Dan; Akova, Murat

    2013-12-01

    Owing to increasing resistance and the limited arsenal of new antibiotics, especially against Gram-negative pathogens, carefully designed antibiotic regimens are obligatory for febrile neutropenic patients, along with effective infection control. The Expert Group of the 4(th) European Conference on Infections in Leukemia has developed guidelines for initial empirical therapy in febrile neutropenic patients, based on: i) the local resistance epidemiology; and ii) the patient's risk factors for resistant bacteria and for a complicated clinical course. An 'escalation' approach, avoiding empirical carbapenems and combinations, should be employed in patients without particular risk factors. A 'de-escalation' approach, with initial broad-spectrum antibiotics or combinations, should be used only in those patients with: i) known prior colonization or infection with resistant pathogens; or ii) complicated presentation; or iii) in centers where resistant pathogens are prevalent at the onset of febrile neutropenia. In the latter case, infection control and antibiotic stewardship also need urgent review. Modification of the initial regimen at 72-96 h should be based on the patient's clinical course and the microbiological results. Discontinuation of antibiotics after 72 h or later should be considered in neutropenic patients with fever of unknown origin who are hemodynamically stable since presentation and afebrile for at least 48 h, irrespective of neutrophil count and expected duration of neutropenia. This strategy aims to minimize the collateral damage associated with antibiotic overuse, and the further selection of resistance.

  9. Status and Trend of Regal Fritillary (Speyeria idalia) (Lepidoptera: Nymphalidae) in the 4th of July Butterfly Count Program in 1977–2014

    PubMed Central

    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

  10. Dynamics of the properties of steppe paleosols of the Sarmatian time (2nd century BC-4th century AD) in relation to secular variations in climatic humidity

    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.

  11. Evidence of human-induced morphodynamic changes along the Campania coastal areas (southern Italy) since the 3rd-4th cent. AD

    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

  12. Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Salivary Gland.

    PubMed

    Seethala, Raja R; Stenman, Göran

    2017-03-01

    The salivary gland section in the 4th edition of the World Health Organization classification of head and neck tumors features the description and inclusion of several entities, the most significant of which is represented by (mammary analogue) secretory carcinoma. This entity was extracted mainly from acinic cell carcinoma based on recapitulation of breast secretory carcinoma and a shared ETV6-NTRK3 gene fusion. Also new is the subsection of "Other epithelial lesions," for which key entities include sclerosing polycystic adenosis and intercalated duct hyperplasia. Many entities have been compressed into their broader categories given clinical and morphologic similarities, or transitioned to a different grouping as was the case with low-grade cribriform cystadenocarcinoma reclassified as intraductal carcinoma (with the applied qualifier of low-grade). Specific grade has been removed from the names of the salivary gland entities such as polymorphous adenocarcinoma, providing pathologists flexibility in assigning grade and allowing for recognition of a broader spectrum within an entity. Cribriform adenocarcinoma of (minor) salivary gland origin continues to be divisive in terms of whether it should be recognized as a distinct category. This chapter also features new key concepts such as high-grade transformation. The new paradigm of translocations and gene fusions being common in salivary gland tumors is featured heavily in this chapter.

  13. The structure of Diagnostic and Statistical Manual of Mental Disorders (4th edition, text revision) personality disorder symptoms in a large national sample.

    PubMed

    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.

  14. European guidelines for empirical antibacterial therapy for febrile neutropenic patients in the era of growing resistance: summary of the 2011 4th European Conference on Infections in Leukemia

    PubMed Central

    Averbuch, Diana; Orasch, Christina; Cordonnier, Catherine; Livermore, David M.; Mikulska, Małgorzata; Viscoli, Claudio; Gyssens, Inge C.; Kern, Winfried V.; Klyasova, Galina; Marchetti, Oscar; Engelhard, Dan; Akova, Murat

    2013-01-01

    Owing to increasing resistance and the limited arsenal of new antibiotics, especially against Gram-negative pathogens, carefully designed antibiotic regimens are obligatory for febrile neutropenic patients, along with effective infection control. The Expert Group of the 4th European Conference on Infections in Leukemia has developed guidelines for initial empirical therapy in febrile neutropenic patients, based on: i) the local resistance epidemiology; and ii) the patient’s risk factors for resistant bacteria and for a complicated clinical course. An ‘escalation’ approach, avoiding empirical carbapenems and combinations, should be employed in patients without particular risk factors. A ‘de-escalation’ approach, with initial broad-spectrum antibiotics or combinations, should be used only in those patients with: i) known prior colonization or infection with resistant pathogens; or ii) complicated presentation; or iii) in centers where resistant pathogens are prevalent at the onset of febrile neutropenia. In the latter case, infection control and antibiotic stewardship also need urgent review. Modification of the initial regimen at 72–96 h should be based on the patient’s clinical course and the microbiological results. Discontinuation of antibiotics after 72 h or later should be considered in neutropenic patients with fever of unknown origin who are hemodynamically stable since presentation and afebrile for at least 48 h, irrespective of neutrophil count and expected duration of neutropenia. This strategy aims to minimize the collateral damage associated with antibiotic overuse, and the further selection of resistance. PMID:24323983

  15. 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.

  16. Frequency Drift Rate Investigation of Solar Radio Burst Type II Due to Coronal Mass Ejections Occurrence on 4th November 2015 Captured by CALLISTO at Sumedang-Indonesia

    NASA Astrophysics Data System (ADS)

    Batubara, M.; Manik, T.; Suryana, R.; Lathif, M.; Sitompul, P.; Zamzam, M.; Mumtahana, F.

    2017-03-01

    The formations type of solar radio bursts can be known base on the frequency range that is detected. The CALLISTO system works with a wide band of the frequency making it possible to detect several types of solar burst. Indonesia exactly at Sumedang, CALLISTO system detected the formation of solar radio bursts forms of type II for the first time on 5 November 2014. On the other side, CALLISTO spectrometer detects and traces the phenomenon of CME (Coronal Mass Ejections) which causes the solar radio burst type II occurrence. In this paper will be calculated frequency drift rate during the occurrence of solar radio bursts of type II phenomenon on 4th November 2015 at 03:30 UT. The results of these calculations will be discussed as a related study of drift rate during the phenomenon of burst type II radio bursts associated with CME. The obtained drift rate during the solar radio bursts events above 2.8 MHz / s with low drift rate so that the speed of the CME that occurred only about 790 km / s as shown from LASCO.

  17. CD4+ Th1 cells promote CD8+ Tc1 cell survival, memory response, tumor localization and therapy by targeted delivery of interleukin 2 via acquired pMHC I complexes.

    PubMed

    Huang, Hui; Hao, Siguo; Li, Fang; Ye, Zhenmin; Yang, Junbao; Xiang, Jim

    2007-02-01

    The cooperative role of CD4+ helper T (Th) cells has been reported for CD8+ cytotoxic T (Tc) cells in tumor eradication. However, its molecular mechanisms have not been well elucidated. We have recently demonstrated that CD4+ Th cells can acquire major histocompatibility complex/peptide I (pMHC I) complexes and costimulatory molecules by dendritic cell (DC) activation, and further stimulate naïve CD8+ T cell proliferation and activation. In this study, we used CD4+ Th1 and CD8+ Tc1 cells derived from ovalbumin (OVA)-specific T cell receptor (TCR) transgenic OT II and OT I mice to study CD4+ Th1 cell's help effects on active CD8+ Tc1 cells and the molecular mechanisms involved in CD8+ Tc1-cell immunotherapy of OVA-expressing EG7 tumors. Our data showed that CD4+ Th1 cells with acquired pMHC I by OVA-pulsed DC (DCOVA) stimulation are capable of prolonging survival and reducing apoptosis formation of active CD8+ Tc1 cells in vitro, and promoting CD8+ Tc1 cell tumor localization and memory responses in vivo by 3-folds. A combined adoptive T-cell therapy of CD8+ Tc1 with CD4+ Th1 cells resulted in regression of well-established EG7 tumors (5 mm in diameter) in all 10/10 mice. The CD4+ Th1's help effect is mediated via the helper cytokine IL-2 specifically targeted to CD8+ Tc1 cells in vivo by acquired pMHC I complexes. Taken together, these results will have important implications for designing adoptive T-cell immunotherapy protocols in treatment of solid tumors.

  18. Application of modified Patankar schemes to stiff biogeochemical models for the water column

    NASA Astrophysics Data System (ADS)

    Burchard, Hans; Deleersnijder, Eric; Meister, Andreas

    2005-12-01

    In this paper, we apply recently developed positivity preserving and conservative Modified Patankar-type solvers for ordinary differential equations to a simple stiff biogeochemical model for the water column. The performance of this scheme is compared to schemes which are not unconditionally positivity preserving (the first-order Euler and the second- and fourth-order Runge-Kutta schemes) and to schemes which are not conservative (the first- and second-order Patankar schemes). The biogeochemical model chosen as a test ground is a standard nutrient-phytoplankton-zooplankton-detritus (NPZD) model, which has been made stiff by substantially decreasing the half saturation concentration for nutrients. For evaluating the stiffness of the biogeochemical model, so-called numerical time scales are defined which are obtained empirically by applying high-resolution numerical schemes. For all ODE solvers under investigation, the temporal error is analysed for a simple exponential decay law. The performance of all schemes is compared to a high-resolution high-order reference solution. As a result, the second-order modified Patankar-Runge-Kutta scheme gives a good agreement with the reference solution even for time steps 10 times longer than the shortest numerical time scale of the problem. Other schemes do either compute negative values for non-negative state variables (fully explicit schemes), violate conservation (the Patankar schemes) or show low accuracy (all first-order schemes).

  19. Assessment of the numerical efficiency of ocean circulation model : Hycom contribution to the COMODO project

    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

  20. A Modular Formal Semantics for Ptolemy

    DTIC Science & Technology

    2011-01-01

    3 the three procedures implement a Runge - Kutta 2(3) ODE solving method . Procedure Runge -Kutta23 performs an integration step, given a state and an...this is the case for numerical solvers of Runge - Kutta type (see Section 6.3). Integrators would be less trivial under a different solver, for...end if end loop return h; The Runge - Kutta procedure roughly works by performing two smaller integration steps at times 0.5 ·h and 0.75 ·h from the

  1. 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.

  2. A hybrid symplectic PIC/spectral scheme for one-dimensional electrostatic simulations

    SciTech Connect

    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.

  3. Ribavirin exerts differential effects on functions of Cd4+ Th1, Th2, and regulatory T cell clones in hepatitis C.

    PubMed

    Langhans, Bettina; Nischalke, Hans Dieter; Arndt, Simone; Braunschweiger, Ingrid; Nattermann, Jacob; Sauerbruch, Tilman; Spengler, Ulrich

    2012-01-01

    Ribavirin improves outcomes of therapy in chronic hepatitis C but its mode of action has still remained unclear. Since ribavirin has been proposed to modulate the host's T cell responses, we studied its direct effects on CD4(+) T cell clones with diverse functional polarization which had been generated from patients with chronic hepatitis C. We analysed in vitro proliferation ([(3)H] thymidine uptake) and cytokine responses (IL-10, IFN-gamma) at varying concentrations of ribavirin (0-10 µg/ml) in 8, 9 and 7 CD4(+) TH1, TH2 and regulatory T cell (Treg) clones, respectively. In co-culture experiments, we further determined effects of ribarivin on inhibition of TH1 and TH2 effector cells by Treg clones. All clones had been generated from peripheral blood of patients with chronic hepatitis C in the presence of HCV core protein. Ribavirin enhanced proliferation of T effector cells and increased production of IFN-gamma in TH1 clones, but had only little effect on IL-10 secretion in TH2 clones. However, ribavirin markedly inhibited IL-10 release in Treg clones in a dose dependent fashion. These Treg clones suppressed proliferation of T effector clones by their IL-10 secretion, and in co-culture assays ribavirin reversed Treg-mediated suppression of T effector cells. Our in vitro data suggest that--in addition to its immunostimulatory effects on TH1 cells--ribavirin can inhibit functions of HCV-specific Tregs and thus reverses Treg-mediated suppression of T effector cells in chronic hepatitis C.

  4. Changes in the regional prevalence of child obesity in 4th, 8th, and 11th grade students in Texas from 2000-2002 to 2004-2005.

    PubMed

    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.

  5. Second-generation surveillance for HIV/AIDS in Pakistan: results from the 4th round of Integrated Behavior and Biological Survey 2011–2012

    PubMed Central

    Emmanuel, Faran; Salim, Momina; Akhtar, Naeem; Arshad, Salwa; Reza, Tahira Ezra

    2013-01-01

    Objectives In an effort to fully analyse and understand the HIV situation and its epidemiology in Pakistan, a bilateral collaboration between the National AIDS Control Program and the Canadian International Development Agency resulted in the establishment of an effective second-generation surveillance (SGS) system for HIV/AIDS between 2004 and 2012 in accordance with the published guidelines. This paper presents findings from the 4th round of SGS. Methods A mapping exercise was initially conducted for size estimations of the key vulnerable populations: people who inject drugs (PWIDs), male sex workers (MSWs), hijra sex workers (HSWs), and female sex workers (FSWs), followed by an Integrated Behavioral and Biological Surveillance in 20 selected cities across Pakistan. Results The estimated sizes of the four key populations mapped in the 20 cities were 89 178 FSWs, 46 351 PWIDs, 23 317 HSWs and 19 119 MSWs. The HIV sero-prevalence among PWIDs was the highest among all key populations surveyed at 37.8% (CI 37.3 to 38.3) nationally, followed by a prevalence of 7.2% (CI 6.8 to 7.5) among HSWs, 3.1% (CI 2.8 to 3.4) among MSWs and 0.8% (CI 0.4 to 1.0) for FSWs. Various key risk behaviours, that is, sharing of syringes by PWIDs and inconsistent use of condoms by sex workers, were documented. Conclusions Pakistan's HIV epidemic that once was characterised primarily by transmission among PWIDs is now increasingly characterised by significant sexual transmission, and all types of sex workers (male, hijra and female) exhibit epidemiological proportions of infection. There is a need to develop concrete strategic plans for each vulnerable subpopulation, initially focusing prevention resources on those with a higher risk or vulnerability. PMID:23912818

  6. How Do 4th, 5th, and 6th Grade Students' Categories of Cognitive Reflections in Interviews on Derivational Morphology Compare to Their Upper Level Spelling Inventory Orthographic Knowledge?

    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…

  7. Fast and accurate implementation of Fourier spectral approximations of nonlocal diffusion operators and its applications

    NASA Astrophysics Data System (ADS)

    Du, Qiang; Yang, Jiang

    2017-03-01

    This work is concerned with the Fourier spectral approximation of various integral differential equations associated with some linear nonlocal diffusion and peridynamic operators under periodic boundary conditions. For radially symmetric kernels, the nonlocal operators under consideration are diagonalizable in the Fourier space so that the main computational challenge is on the accurate and fast evaluation of their eigenvalues or Fourier symbols consisting of possibly singular and highly oscillatory integrals. For a large class of fractional power-like kernels, we propose a new approach based on reformulating the Fourier symbols both as coefficients of a series expansion and solutions of some simple ODE models. We then propose a hybrid algorithm that utilizes both truncated series expansions and high order Runge-Kutta ODE solvers to provide fast evaluation of Fourier symbols in both one and higher dimensional spaces. It is shown that this hybrid algorithm is robust, efficient and accurate. As applications, we combine this hybrid spectral discretization in the spatial variables and the fourth-order exponential time differencing Runge-Kutta for temporal discretization to offer high order approximations of some nonlocal gradient dynamics including nonlocal Allen-Cahn equations, nonlocal Cahn-Hilliard equations, and nonlocal phase-field crystal models. Numerical results show the accuracy and effectiveness of the fully discrete scheme and illustrate some interesting phenomena associated with the nonlocal models.

  8. Efficient and Accurate Explicit Integration Algorithms with Application to Viscoplastic Models

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.

    1994-01-01

    Several explicit integration algorithms with self-adative time integration strategies are developed and investigated for efficiency and accuracy. These algorithms involve the Runge-Kutta second order, the lower Runge-Kutta method of orders one and two, and the exponential integration method. The algorithms are applied to viscoplastic models put forth by Freed and Verrilli and Bodner and Partom for thermal/mechanical loadings (including tensile, relaxation, and cyclic loadings). The large amount of computations performed showed that, for comparable accuracy, the efficiency of an integration algorithm depends significantly on the type of application (loading). However, in general, for the aforementioned loadings and viscoplastic models, the exponential integration algorithm with the proposed self-adaptive time integration strategy worked more (or comparably) efficiently and accurately than the other integration algorithms. Using this strategy for integrating viscoplastic models may lead to considerable savings in computer time (better efficiency) without adversely affecting the accuracy of the results. This conclusion should encourage the utilization of viscoplastic models in the stress analysis and design of structural components.

  9. Accelerated solution of non-linear flow problems using Chebyshev iteration polynomial based RK recursions

    SciTech Connect

    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.

  10. 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.

  11. Shuttle program. Onorbit navigation integrator results for typical shuttle orbits

    NASA Technical Reports Server (NTRS)

    Olszewski, O. W.

    1979-01-01

    Three types of navigation onorbit numerical integrators were evaluated: (1) power integrators with no delta-V incorporation, just coasting (using Taylor series expansion integrators); (2) coasting integrators using the Cowell method of special perturbations; and (3) coasting integrator using the Pines variation of parameter perturbation method. Results show that the super G integrator is a very simple and effective for 2 and 4 second time steps. Since IMU delta-V data can be easily incorporated in the integration scheme, its use as the standard onorbit navigation propagator for the maintenance of the current state was implemented in the onboard navigation software. The Pines formulation method with a Runge-Kutta-Gill fourth-order integrator method produces excellent results up to 300 second time steps. On orbit prediction with this method was implemented in the onboard onorbit navigation scheme. The Runge-Kutta third order, using Cowell's method, is an excellent general purpose determination integrator for time steps up to a 60 second duration.

  12. New Wisdom to Defy an Old Enemy: Summary from a scientific symposium at the 4th Influenza Vaccines for the World (IVW) 2012 Congress, 11 October, Valencia, Spain.

    PubMed

    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

  13. Anomalous transport in second order hydrodynamics

    NASA Astrophysics Data System (ADS)

    Megías, Eugenio; Valle, Manuel

    2016-11-01

    We study the non-dissipative transport effects appearing at second order in the hydrodynamic expansion for a non-interacting gas of chiral fermions by using the partition function formalism. We discuss some features of the corresponding constitutive relations, derive the explicit expressions for the conductivities and compare with existing results in the literature. Talk given by E. Megías at the 4th International Conference on New Frontiers in Physics (ICNFP 2015), 23-30 August 2015, Kolymbari, Crete, Greece.

  14. General approach to the testing of binary solubility systems for thermodynamic consistency. Consolidated Fuel Reprocessing Program

    SciTech Connect

    Hamm, L.L.; Van Brunt, V.

    1982-08-01

    A comparison of implicit Runge-Kutta and orthogonal collocation methods is made for the numerical solution to the ordinary differential equation which describes the high-pressure vapor-liquid equilibria of a binary system. The systems of interest are limited to binary solubility systems where one of the components is supercritical and exists as a noncondensable gas in the pure state. Of the two methods - implicit Runge-Kuta and orthogonal collocation - this paper attempts to present some preliminary but not necessarily conclusive results that the implicit Runge-Kutta method is superior for the solution to the ordinary differential equation utilized in the thermodynamic consistency testing of binary solubility systems. Due to the extreme nonlinearity of thermodynamic properties in the region near the critical locus, an extended cubic spline fitting technique is devised for correlating the P-x data. The least-squares criterion is employed in smoothing the experimental data. Even though the derivation is presented specifically for the correlation of P-x data, the technique could easily be applied to any thermodynamic data by changing the endpoint requirements. The volumetric behavior of the systems must be given or predicted in order to perform thermodynamic consistency tests. A general procedure is developed for predicting the volumetric behavior required and some indication as to the expected limit of accuracy is given.

  15. An efficient time advancing strategy for energy-preserving simulations

    NASA Astrophysics Data System (ADS)

    Capuano, F.; Coppola, G.; de Luca, L.

    2015-08-01

    Energy-conserving numerical methods are widely employed within the broad area of convection-dominated systems. Semi-discrete conservation of energy is usually obtained by adopting the so-called skew-symmetric splitting of the non-linear convective term, defined as a suitable average of the divergence and advective forms. Although generally allowing global conservation of kinetic energy, it has the drawback of being roughly twice as expensive as standard divergence or advective forms alone. In this paper, a general theoretical framework has been developed to derive an efficient time-advancement strategy in the context of explicit Runge-Kutta schemes. The novel technique retains the conservation properties of skew-symmetric-based discretizations at a reduced computational cost. It is found that optimal energy conservation can be achieved by properly constructed Runge-Kutta methods in which only divergence and advective forms for the convective term are used. As a consequence, a considerable improvement in computational efficiency over existing practices is achieved. The overall procedure has proved to be able to produce new schemes with a specified order of accuracy on both solution and energy. The effectiveness of the method as well as the asymptotic behavior of the schemes is demonstrated by numerical simulation of Burgers' equation.

  16. BSSN equations in spherical coordinates without regularization: Vacuum and nonvacuum spherically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Montero, Pedro J.; Cordero-Carrión, Isabel

    2012-06-01

    Brown [Phys. Rev. DPRVDAQ1550-7998 79, 104029 (2009)] has recently introduced a covariant formulation of the BSSN equations which is well suited for curvilinear coordinate systems. This is particularly desirable as many astrophysical phenomena are symmetric with respect to the rotation axis or are such that curvilinear coordinates adapt better to their geometry. However, the singularities associated with such coordinate systems are known to lead to numerical instabilities unless special care is taken (e.g., regularization at the origin). Cordero-Carrión will present a rigorous derivation of partially implicit Runge-Kutta methods in forthcoming papers, with the aim of treating numerically the stiff source terms in wavelike equations that may appear as a result of the choice of the coordinate system. We have developed a numerical code solving the BSSN equations in spherical symmetry and the general relativistic hydrodynamic equations written in flux-conservative form. A key feature of the code is that it uses a second-order partially implicit Runge-Kutta method to integrate the evolution equations. We perform and discuss a number of tests to assess the accuracy and expected convergence of the code—namely a pure gauge wave, the evolution of a single black hole, the evolution of a spherical relativistic star in equilibrium, and the gravitational collapse of a spherical relativistic star leading to the formation of a black hole. We obtain stable evolutions of regular spacetimes without the need for any regularization algorithm at the origin.

  17. 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.

  18. Recovery Discontinuous Galerkin Jacobian-Free Newton-Krylov Method for All-Speed Flows

    SciTech Connect

    HyeongKae Park; Robert Nourgaliev; Vincent Mousseau; Dana Knoll

    2008-07-01

    A novel numerical algorithm (rDG-JFNK) for all-speed fluid flows with heat conduction and viscosity is introduced. The rDG-JFNK combines the Discontinuous Galerkin spatial discretization with the implicit Runge-Kutta time integration under the Jacobian-free Newton-Krylov framework. We solve fully-compressible Navier-Stokes equations without operator-splitting of hyperbolic, diffusion and reaction terms, which enables fully-coupled high-order temporal discretization. The stability constraint is removed due to the L-stable Explicit, Singly Diagonal Implicit Runge-Kutta (ESDIRK) scheme. The governing equations are solved in the conservative form, which allows one to accurately compute shock dynamics, as well as low-speed flows. For spatial discretization, we develop a “recovery” family of DG, exhibiting nearly-spectral accuracy. To precondition the Krylov-based linear solver (GMRES), we developed an “Operator-Split”-(OS) Physics Based Preconditioner (PBP), in which we transform/simplify the fully-coupled system to a sequence of segregated scalar problems, each can be solved efficiently with Multigrid method. Each scalar problem is designed to target/cluster eigenvalues of the Jacobian matrix associated with a specific physics.

  19. Radiative transfer equation for predicting light propagation in biological media: comparison of a modified finite volume method, the Monte Carlo technique, and an exact analytical solution.

    PubMed

    Asllanaj, Fatmir; Contassot-Vivier, Sylvain; Liemert, André; Kienle, Alwin

    2014-01-01

    We examine the accuracy of a modified finite volume method compared to analytical and Monte Carlo solutions for solving the radiative transfer equation. The model is used for predicting light propagation within a two-dimensional absorbing and highly forward-scattering medium such as biological tissue subjected to a collimated light beam. Numerical simulations for the spatially resolved reflectance and transmittance are presented considering refractive index mismatch with Fresnel reflection at the interface, homogeneous and two-layered media. Time-dependent as well as steady-state cases are considered. In the steady state, it is found that the modified finite volume method is in good agreement with the other two methods. The relative differences between the solutions are found to decrease with spatial mesh refinement applied for the modified finite volume method obtaining <2.4%. In the time domain, the fourth-order Runge-Kutta method is used for the time semi-discretization of the radiative transfer equation. An agreement among the modified finite volume method, Runge-Kutta method, and Monte Carlo solutions are shown, but with relative differences higher than in the steady state.

  20. 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.