WorldWideScience

Sample records for numerous practical problems

  1. Numerical problems in physics

    CERN Document Server

    Singh, Devraj

    2015-01-01

    Numerical Problems in Physics, Volume 1 is intended to serve the need of the students pursuing graduate and post graduate courses in universities with Physics and Materials Science as subject including those appearing in engineering, medical, and civil services entrance examinations. KEY FEATURES: * 29 chapters on Optics, Wave & Oscillations, Electromagnetic Field Theory, Solid State Physics & Modern Physics * 540 solved numerical problems of various universities and ompetitive examinations * 523 multiple choice questions for quick and clear understanding of subject matter * 567 unsolved numerical problems for grasping concepts of the various topic in Physics * 49 Figures for understanding problems and concept

  2. Numerical models for differential problems

    CERN Document Server

    Quarteroni, Alfio

    2017-01-01

    In this text, we introduce the basic concepts for the numerical modelling of partial differential equations. We consider the classical elliptic, parabolic and hyperbolic linear equations, but also the diffusion, transport, and Navier-Stokes equations, as well as equations representing conservation laws, saddle-point problems and optimal control problems. Furthermore, we provide numerous physical examples which underline such equations. We then analyze numerical solution methods based on finite elements, finite differences, finite volumes, spectral methods and domain decomposition methods, and reduced basis methods. In particular, we discuss the algorithmic and computer implementation aspects and provide a number of easy-to-use programs. The text does not require any previous advanced mathematical knowledge of partial differential equations: the absolutely essential concepts are reported in a preliminary chapter. It is therefore suitable for students of bachelor and master courses in scientific disciplines, an...

  3. Numerical convergence for a sewage disposal problem

    OpenAIRE

    Alvarez-Vázquez, L.J.; Martínez, A.; Rodríguez, C.; Vázquez-Méndez, M.E.

    2001-01-01

    The management of sewage disposal and the design of wastewater treatment systems can be formulated as a constrained pointwise optimal control problem. In this paper we study the convergence of the numerical resolution for the corresponding state system by means of a characteristics Galerkin method. The main difficulty of the problem is due to the existence of Radon measures in the right-hand side of the state system. Finally, we present numerical results for a realistic problem posed in a ria...

  4. Average-case analysis of numerical problems

    CERN Document Server

    2000-01-01

    The average-case analysis of numerical problems is the counterpart of the more traditional worst-case approach. The analysis of average error and cost leads to new insight on numerical problems as well as to new algorithms. The book provides a survey of results that were mainly obtained during the last 10 years and also contains new results. The problems under consideration include approximation/optimal recovery and numerical integration of univariate and multivariate functions as well as zero-finding and global optimization. Background material, e.g. on reproducing kernel Hilbert spaces and random fields, is provided.

  5. Numerical methods for hyperbolic differential functional problems

    Directory of Open Access Journals (Sweden)

    Roman Ciarski

    2008-01-01

    Full Text Available The paper deals with the initial boundary value problem for quasilinear first order partial differential functional systems. A general class of difference methods for the problem is constructed. Theorems on the error estimate of approximate solutions for difference functional systems are presented. The convergence results are proved by means of consistency and stability arguments. A numerical example is given.

  6. Numerical methods and analysis of multiscale problems

    CERN Document Server

    Madureira, Alexandre L

    2017-01-01

    This book is about numerical modeling of multiscale problems, and introduces several asymptotic analysis and numerical techniques which are necessary for a proper approximation of equations that depend on different physical scales. Aimed at advanced undergraduate and graduate students in mathematics, engineering and physics – or researchers seeking a no-nonsense approach –, it discusses examples in their simplest possible settings, removing mathematical hurdles that might hinder a clear understanding of the methods. The problems considered are given by singular perturbed reaction advection diffusion equations in one and two-dimensional domains, partial differential equations in domains with rough boundaries, and equations with oscillatory coefficients. This work shows how asymptotic analysis can be used to develop and analyze models and numerical methods that are robust and work well for a wide range of parameters.

  7. Numerical stability in problems of linear algebra.

    Science.gov (United States)

    Babuska, I.

    1972-01-01

    Mathematical problems are introduced as mappings from the space of input data to that of the desired output information. Then a numerical process is defined as a prescribed recurrence of elementary operations creating the mapping of the underlying mathematical problem. The ratio of the error committed by executing the operations of the numerical process (the roundoff errors) to the error introduced by perturbations of the input data (initial error) gives rise to the concept of lambda-stability. As examples, several processes are analyzed from this point of view, including, especially, old and new processes for solving systems of linear algebraic equations with tridiagonal matrices. In particular, it is shown how such a priori information can be utilized as, for instance, a knowledge of the row sums of the matrix. Information of this type is frequently available where the system arises in connection with the numerical solution of differential equations.

  8. Numerical simulations of coupled problems in engineering

    CERN Document Server

    2014-01-01

    This book presents and discusses mathematical models, numerical methods and computational techniques used for solving coupled problems in science and engineering. It takes a step forward in the formulation and solution of real-life problems with a multidisciplinary vision, accounting for all of the complex couplings involved in the physical description. Simulation of multifaceted physics problems is a common task in applied research and industry. Often a suitable solver is built by connecting together several single-aspect solvers into a network. In this book, research in various fields was selected for consideration: adaptive methodology for multi-physics solvers, multi-physics phenomena and coupled-field solutions, leading to computationally intensive structural analysis. The strategies which are used to keep these problems computationally affordable are of special interest, and make this an essential book.

  9. Numerical Methods for Free Boundary Problems

    CERN Document Server

    1991-01-01

    About 80 participants from 16 countries attended the Conference on Numerical Methods for Free Boundary Problems, held at the University of Jyviiskylii, Finland, July 23-27, 1990. The main purpose of this conference was to provide up-to-date information on important directions of research in the field of free boundary problems and their numerical solutions. The contributions contained in this volume cover the lectures given in the conference. The invited lectures were given by H.W. Alt, V. Barbu, K-H. Hoffmann, H. Mittelmann and V. Rivkind. In his lecture H.W. Alt considered a mathematical model and existence theory for non-isothermal phase separations in binary systems. The lecture of V. Barbu was on the approximate solvability of the inverse one phase Stefan problem. K-H. Hoff­ mann gave an up-to-date survey of several directions in free boundary problems and listed several applications, but the material of his lecture is not included in this proceedings. H.D. Mittelmann handled the stability of thermo capi...

  10. Problem Solving in Practice

    Science.gov (United States)

    Greene, Kim; Heyck-Williams, Jeff; Timpson Gray, Elicia

    2017-01-01

    Problem solving spans all grade levels and content areas, as evidenced by this compilation of projects from schools across the United States. In one project, high school girls built a solar-powered tent to serve their city's homeless population. In another project, 4th graders explored historic Jamestown to learn about the voices lost to history.…

  11. Numerical solution of the multichannel scattering problem

    International Nuclear Information System (INIS)

    Korobov, V.I.

    1992-01-01

    A numerical algorithm for solving the multichannel elastic and inelastic scattering problem is proposed. The starting point is the system of radial Schroedinger equations with linear boundary conditions imposed at some point R=R m placed somewhere in asymptotic region. It is discussed how the obtained linear equation can be splitted into a zero-order operator and its pertturbative part. It is shown that Lentini - Pereyra variable order finite-difference method appears to be very suitable for solving that kind of problems. The derived procedure is applied to dμ+t→tμ+d inelastic scattering in the framework of the adiabatic multichannel approach. 19 refs.; 1 fig.; 1 tab

  12. Numerical methods for coupled fracture problems

    Science.gov (United States)

    Viesca, Robert C.; Garagash, Dmitry I.

    2018-04-01

    We consider numerical solutions in which the linear elastic response to an opening- or sliding-mode fracture couples with one or more processes. Classic examples of such problems include traction-free cracks leading to stress singularities or cracks with cohesive-zone strength requirements leading to non-singular stress distributions. These classical problems have characteristic square-root asymptotic behavior for stress, relative displacement, or their derivatives. Prior work has shown that such asymptotics lead to a natural quadrature of the singular integrals at roots of Chebyhsev polynomials of the first, second, third, or fourth kind. We show that such quadratures lead to convenient techniques for interpolation, differentiation, and integration, with the potential for spectral accuracy. We further show that these techniques, with slight amendment, may continue to be used for non-classical problems which lack the classical asymptotic behavior. We consider solutions to example problems of both the classical and non-classical variety (e.g., fluid-driven opening-mode fracture and fault shear rupture driven by thermal weakening), with comparisons to analytical solutions or asymptotes, where available.

  13. Practical design of magnetostatic structure using numerical simulation

    CERN Document Server

    Wang, Qiuliang

    2013-01-01

    Covers the practical numerical method for the analysis and design of magnets Extensively covers the magnet design and computation aspects from theories to practical applications, emphasizing design methods of practical structures such as superconducting, electromagnetic and permanent magnet for use in various scientific instruments, industrial processing, biomedicine and special electrical equipments. The computations cover a wide range of numerical techniques and analytical derivation to efficiently provide solutions to complicated problems that are often encountered in practice, where simple analytical calculations are no longer adequate. Chapters include: Introduction of Magnet Technology, Magnetostatic Equation for the Magnet Structure, Finite Element Analysis for Magnetostatic Field, Integral Method for Magnetostatic Field, Numerical Method of Solenoid Coils Design, Series Analysis of Axially Symmetric Magnetic Field, Magnets with High Magnetic Field and High Homogeneity, Permanent Magnet and its App...

  14. Numerical methods for hydrodynamic stability problems

    International Nuclear Information System (INIS)

    Fujimura, Kaoru

    1985-11-01

    Numerical methods for solving the Orr-Sommerfeld equation, which is the fundamental equation of the hydrodynamic stability theory for various shear flows, are reviewed and typical numerical results are presented. The methods of asymptotic solution, finite difference methods, initial value methods and expansions in orthogonal functions are compared. (author)

  15. Mathematical modelling and numerical simulation of oil pollution problems

    CERN Document Server

    2015-01-01

    Written by outstanding experts in the fields of marine engineering, atmospheric physics and chemistry, fluid dynamics and applied mathematics, the contributions in this book cover a wide range of subjects, from pure mathematics to real-world applications in the oil spill engineering business. Offering a truly interdisciplinary approach, the authors present both mathematical models and state-of-the-art numerical methods for adequately solving the partial differential equations involved, as well as highly practical experiments involving actual cases of ocean oil pollution. It is indispensable that different disciplines of mathematics, like analysis and numerics,  together with physics, biology, fluid dynamics, environmental engineering and marine science, join forces to solve today’s oil pollution problems.   The book will be of great interest to researchers and graduate students in the environmental sciences, mathematics and physics, showing the broad range of techniques needed in order to solve these poll...

  16. A numerical approach to Stefan problem

    International Nuclear Information System (INIS)

    Kotalik, P.

    1993-07-01

    The one-dimensional Stefan problem for a thin plate heated by laser pulses is solved by approximating the enthalpy formulation of the problem by C 0 piecewise linear finite elements in space combined with a semi-implicit scheme in time. (author) 6 figs., 5 refs

  17. Problems in practical radiation education

    Energy Technology Data Exchange (ETDEWEB)

    Turuoka, Moriaki [Hokkaido Sapporo Kaisei Senior High School, Sapporo, Hokkaido (Japan)

    1999-09-01

    Based on the results of questionnaire survey carried out in 1995 and 1997 and addressed to the same students in a senior high school, Japan, the author arrived at a conclusion that the students had the chance to get information on radiation from the mass media other than at school during two school year. At school they learn through a textbook and also complementary educational materials the teachers provide which will help understanding and improving the interests in radiations. In the practice, some important problems remain unsolved: the student's feeling toward radiations as risky, inadequate descriptions on radiations found in the textbook, and the difficulties in obtaining teaching materials for experiments. These problems must be resolved first of all for the solution of our future energy supply. (S. Ohno)

  18. Numerical Simulation of Some Biomechanical Problems

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Klézl, Z.; Fousek, J.; Kestřánek, Zdeněk; Stehlík, J.

    2003-01-01

    Roč. 61, 3-6 (2003), s. 283-295 ISSN 0378-4754. [MODELLING 2001. IMACS Conference on Mathematical Modelling and Computational Methods in Mechanics, Physics , Biomechanics and Geodynamics /2./. Pilsen, 19.06.2001-25.06.2001] Institutional research plan: AV0Z1030915 Keywords : non-linear elasticity * contact problems * variational inequality * finite element method * wrist * spine * fracture Subject RIV: BA - General Mathematics Impact factor: 0.558, year: 2003

  19. Numerical solution of electrostatic problems of the accelerator project VICKSI

    International Nuclear Information System (INIS)

    Janetzki, U.

    1975-03-01

    In this work, the numerical solution to a few of the electrostatic problems is dealt with which have occured within the framework of the heavy ion accelerator project VICKSI. By means of these selected examples, the versatile applicability of the numerical method is to be demonstrated, and simultaneously assistance is given for the solution of similar problems. The numerical process for solving ion-optics problems consists generally of two steps. In the first step, the potential distribution for a given boundary value problem is iteratively calculated for the Laplace equation, and then the image characteristics of the electostatic lense are investigated using the Raytrace method. (orig./LH) [de

  20. Numerical solutions of the N-body problem

    International Nuclear Information System (INIS)

    Marciniak, A.

    1985-01-01

    Devoted to the study of numerical methods for solving the general N-body problem and related problems, this volume starts with an overview of the conventional numerical methods for solving the initial value problem. The major part of the book contains original work and features a presentation of special numerical methods conserving the constants of motion in the general N-body problem and methods conserving the Jacobi constant in the problem of motion of N bodies in a rotating frame, as well as an analysis of the applications of both (conventional and special) kinds of methods for solving these problems. For all the methods considered, the author presents algorithms which are easily programmable in any computer language. Moreover, the author compares various methods and presents adequate numerical results. The appendix contains PL/I procedures for all the special methods conserving the constants of motion. 91 refs.; 35 figs.; 41 tabs

  1. Numerical Methods for Bayesian Inverse Problems

    KAUST Repository

    Ernst, Oliver

    2014-01-06

    We present recent results on Bayesian inversion for a groundwater flow problem with an uncertain conductivity field. In particular, we show how direct and indirect measurements can be used to obtain a stochastic model for the unknown. The main tool here is Bayes’ theorem which merges the indirect data with the stochastic prior model for the conductivity field obtained by the direct measurements. Further, we demonstrate how the resulting posterior distribution of the quantity of interest, in this case travel times of radionuclide contaminants, can be obtained by Markov Chain Monte Carlo (MCMC) simulations. Moreover, we investigate new, promising MCMC methods which exploit geometrical features of the posterior and which are suited to infinite dimensions.

  2. Numerical Methods for Bayesian Inverse Problems

    KAUST Repository

    Ernst, Oliver; Sprungk, Bjorn; Cliffe, K. Andrew; Starkloff, Hans-Jorg

    2014-01-01

    We present recent results on Bayesian inversion for a groundwater flow problem with an uncertain conductivity field. In particular, we show how direct and indirect measurements can be used to obtain a stochastic model for the unknown. The main tool here is Bayes’ theorem which merges the indirect data with the stochastic prior model for the conductivity field obtained by the direct measurements. Further, we demonstrate how the resulting posterior distribution of the quantity of interest, in this case travel times of radionuclide contaminants, can be obtained by Markov Chain Monte Carlo (MCMC) simulations. Moreover, we investigate new, promising MCMC methods which exploit geometrical features of the posterior and which are suited to infinite dimensions.

  3. A numerical study for global atmospheric transport-chemistry problems

    NARCIS (Netherlands)

    E.J. Spee (Edwin); J.G. Verwer (Jan); P.M. de Zeeuw (Paul); J.G. Blom (Joke); W. Hundsdorfer (Willem)

    1998-01-01

    htmlabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents

  4. A numerical study for global atmospheric transport-chemistry problems

    NARCIS (Netherlands)

    E.J. Spee (Edwin); J.G. Verwer (Jan); P.M. de Zeeuw (Paul); J.G. Blom (Joke); W. Hundsdorfer (Willem)

    1997-01-01

    textabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents

  5. About numerical analysis of a plasma physics problem

    International Nuclear Information System (INIS)

    Almeida Cipolatti, R. de

    1985-01-01

    A numerical study on macroscopic equilibrium of a plasma at interior of a tokamak device, considering boundary problems for the case which f(s)=sis presented. The abstract Dirichlet problem enumerating main results which is applied to plasma model is studied. (M.C.K.) [pt

  6. An Energy Based Numerical Approach to Phase Change Problems

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Anders Boe; Damkilde, Lars; Krenk, Steen

    1996-01-01

    Phase change problems, occurring e.g. in melting, casting and freezing processes, are often characterized by a very narrow transition zone with very lareg changes in heat capacity and conductivity. This leads to problems in numerical procedures, where the transition zone propagates through a mesh...

  7. Numerical method of singular problems on singular integrals

    International Nuclear Information System (INIS)

    Zhao Huaiguo; Mou Zongze

    1992-02-01

    As first part on the numerical research of singular problems, a numerical method is proposed for singular integrals. It is shown that the procedure is quite powerful for solving physics calculation with singularity such as the plasma dispersion function. Useful quadrature formulas for some class of the singular integrals are derived. In general, integrals with more complex singularities can be dealt by this method easily

  8. Numerical simulation for two-phase jet problem

    International Nuclear Information System (INIS)

    Lee, W.H.; Shah, V.L.

    1981-01-01

    A computer program TWOP was developed for obtaining the numerical solutions of three-dimensional, transient, two-phase flow system with nonequilibrium and nonhomogeneous conditions. TWOP employs two-fluid model and a set of the conservation equations formulated by Harlow and Amsden along with their Implicit Multi-Field (IMF) numerical technique that allows all degrees of couplings between the two fields. We have further extended the procedure of Harlow and Amsden by incorporating the implicit couplings of phase transition and interfacial heat transfer terms in the energy equations. Numerical results of two tested problems are presented to demonstrate the capabilities of the TWOP code. The first problem is the separation of vapor and liquid, showing that the code can handle the computational difficulties such as liquid packing and sharp interface phenomena. The second problem is the high pressure two-phase jet impinged on vertical plate, demonstrating the important role of the interfacial mass and momentum exchange

  9. 7th International Conference on Hyperbolic Problems Theory, Numerics, Applications

    CERN Document Server

    Jeltsch, Rolf

    1999-01-01

    These proceedings contain, in two volumes, approximately one hundred papers presented at the conference on hyperbolic problems, which has focused to a large extent on the laws of nonlinear hyperbolic conservation. Two-fifths of the papers are devoted to mathematical aspects such as global existence, uniqueness, asymptotic behavior such as large time stability, stability and instabilities of waves and structures, various limits of the solution, the Riemann problem and so on. Roughly the same number of articles are devoted to numerical analysis, for example stability and convergence of numerical schemes, as well as schemes with special desired properties such as shock capturing, interface fitting and high-order approximations to multidimensional systems. The results in these contributions, both theoretical and numerical, encompass a wide range of applications such as nonlinear waves in solids, various computational fluid dynamics from small-scale combustion to relativistic astrophysical problems, multiphase phe...

  10. Numerical treatment of free surface problems in ferrohydrodynamics

    International Nuclear Information System (INIS)

    Lavrova, O; Matthies, G; Mitkova, T; Polevikov, V; Tobiska, L

    2006-01-01

    The numerical treatment of free surface problems in ferrohydrodynamics is considered. Starting from the general model, special attention is paid to field-surface and flow-surface interactions. Since in some situations these feedback interactions can be partly or even fully neglected, simpler models can be derived. The application of such models to the numerical simulation of dissipative systems, rotary shaft seals, equilibrium shapes of ferrofluid drops, and pattern formation in the normal-field instability of ferrofluid layers is given. Our numerical strategy is able to recover solitary surface patterns which were discovered recently in experiments

  11. Practice and Problems in Denmark

    DEFF Research Database (Denmark)

    Larsen, Torben

    our practice gradually has arisen. With basis in the University of Aalborg, Denmark, the author has been involved in research and design of sea outfalls since the beginning of the seventies. It is controversial to give examples of dis-functioning sea outfalls by name and it has therefore been avoided...

  12. Benchmark problems for numerical implementations of phase field models

    International Nuclear Information System (INIS)

    Jokisaari, A. M.; Voorhees, P. W.; Guyer, J. E.; Warren, J.; Heinonen, O. G.

    2016-01-01

    Here, we present the first set of benchmark problems for phase field models that are being developed by the Center for Hierarchical Materials Design (CHiMaD) and the National Institute of Standards and Technology (NIST). While many scientific research areas use a limited set of well-established software, the growing phase field community continues to develop a wide variety of codes and lacks benchmark problems to consistently evaluate the numerical performance of new implementations. Phase field modeling has become significantly more popular as computational power has increased and is now becoming mainstream, driving the need for benchmark problems to validate and verify new implementations. We follow the example set by the micromagnetics community to develop an evolving set of benchmark problems that test the usability, computational resources, numerical capabilities and physical scope of phase field simulation codes. In this paper, we propose two benchmark problems that cover the physics of solute diffusion and growth and coarsening of a second phase via a simple spinodal decomposition model and a more complex Ostwald ripening model. We demonstrate the utility of benchmark problems by comparing the results of simulations performed with two different adaptive time stepping techniques, and we discuss the needs of future benchmark problems. The development of benchmark problems will enable the results of quantitative phase field models to be confidently incorporated into integrated computational materials science and engineering (ICME), an important goal of the Materials Genome Initiative.

  13. Solution of Milne problem by Laplace transformation with numerical inversion

    International Nuclear Information System (INIS)

    Campos Velho, H.F. de.

    1987-12-01

    The Milne problem for monoenergetic neutrons, by Laplace Transform of the neutron transport integral equation with numerical inversion of the transformed solution by gaussian quadrature, using the fatorization of the dispersion function. The resulted is solved compared its analitical solution. (author) [pt

  14. Numerical treatment of the unsteady hydromagnetic thermal boundary layer problem

    International Nuclear Information System (INIS)

    Drymonitou, M.A.; Geroyannis, V.S.; Goudas, C.L.

    1980-01-01

    This paper presents a suitable numerical method for the treatment of the unsteady hydromagnetic thermal boundary layer problem for flows past an infinite porous flat plate, the motion of which is governed by a general time-dependent law, under the influence of a transverse externally set magnetic field. The normal velocity of suction/injection at the plate is also assumed to be time-dependent. The results obtained on the basis of numerical approximations seem to compare favourably with earlier results (Pande et al., 1976; Tokis, 1978). Analytical approximations are given for the cases of a plate (i) generally accelerated and (ii) harmonically oscillating. The direct numerical treatment is obviously advantageous since it allows handling of cases where the known methods for analytical approximations are not applicable. This problem is closely related to the motions and heat transfer occurring locally on the surfaces of stars. (orig.)

  15. On the numerical treatment of selected oscillatory evolutionary problems

    Science.gov (United States)

    Cardone, Angelamaria; Conte, Dajana; D'Ambrosio, Raffaele; Paternoster, Beatrice

    2017-07-01

    We focus on evolutionary problems whose qualitative behaviour is known a-priori and exploited in order to provide efficient and accurate numerical schemes. For classical numerical methods, depending on constant coefficients, the required computational effort could be quite heavy, due to the necessary employ of very small stepsizes needed to accurately reproduce the qualitative behaviour of the solution. In these situations, it may be convenient to use special purpose formulae, i.e. non-polynomially fitted formulae on basis functions adapted to the problem (see [16, 17] and references therein). We show examples of special purpose strategies to solve two families of evolutionary problems exhibiting periodic solutions, i.e. partial differential equations and Volterra integral equations.

  16. Practice and problems with gastrostomies.

    Science.gov (United States)

    McHattie, Gill

    2005-08-01

    The development of gastrostomy placement has been an important technological advance in the enteral-access field. However, its rapid growth in popularity could be viewed as problematic. The endoscopist or intervention radiologist can no longer act as a technician but requires to follow-up this group of patients in order to determine outcomes that will inform future practice. There has been emphasis on the importance of the multidisciplinary team in informing and assessing patients referred for gastrostomy insertion. Communication between all the professionals caring for a patient and between the carers and the patient allows information to be collated that will determine the benefits and burdens of long-term gastrostomy feeding. At present much of the published experience is limited to the acute care setting. The incidence of complications varies, depending on the investigator's definition of complication and the diagnosis of the patient group. Many reported studies are retrospective, which puts limitations on documentation. Increasing numbers of patients with diverse needs are now being discharged into the community with gastrostomy tubes in place. Whilst the hospital should ensure that written protocols are provided and that all carers involved should have adequate training, it is not unusual for patients to receive mixed messages from the different care teams responsible for their care. In South Glasgow NHS Hospital Division key members of all teams caring for these patients (acute care, community district nurses, learning disabilities team, physical disabilities team and commercial homecare companies) meet regularly to discuss equipment and protocols. The members of this group feel that this approach has improved communication, standardised practice and reduced complications by providing a service that delivers artificial nutrition support but is primarily suited to the patient's disease process.

  17. Numerical solution of non-linear diffusion problems

    International Nuclear Information System (INIS)

    Carmen, A. del; Ferreri, J.C.

    1998-01-01

    This paper presents a method for the numerical solution of non-linear diffusion problems using finite-differences in moving grids. Due to the presence of steep fronts in the solution domain and to the presence of advective terms originating in the grid movement, an implicit TVD scheme, first order in time and second order in space has been developed. Some algebraic details of the derivation are given. Results are shown for the pure advection of a scalar as a test case and an example dealing with the slow spreading of viscous fluids over plane surfaces. The agreement between numerical and analytical solutions is excellent. (author). 8 refs., 3 figs

  18. Numerical algorithms for contact problems in linear elastostatics

    International Nuclear Information System (INIS)

    Barbosa, H.J.C.; Feijoo, R.A.

    1984-01-01

    In this work contact problems in linear elasticity are analysed by means of Finite Elements and Mathematical Programming Techniques. The principle of virtual work leads in this case to a variational inequality which in turn is equivalent, for Hookean materials and infinitesimal strains, to the minimization of the total potential energy over the set of all admissible virtual displacements. The use of Gauss-Seidel algorithm with relaxation and projection and also Lemke's algorithm and Uzawa's algorithm for solving the minimization problem is discussed. Finally numerical examples are presented. (Author) [pt

  19. Numerical problems with the Pascal triangle in moment computation

    Czech Academy of Sciences Publication Activity Database

    Kautsky, J.; Flusser, Jan

    2016-01-01

    Roč. 306, č. 1 (2016), s. 53-68 ISSN 0377-0427 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : moment computation * Pascal triangle * appropriate polynomial basis * numerical problems Subject RIV: JD - Computer Applications, Robotics Impact factor: 1.357, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/flusser-0459096.pdf

  20. Development of numerical methods for thermohydraulic problems in reactor safety

    International Nuclear Information System (INIS)

    Chabrillac, M.; Kavenoky, A.; Le Coq, G.; L'Heriteau, J.P.; Stewart, B.; Rousseau, J.C.

    1976-01-01

    Numerical methods are being developed for the LOCA calculation; the first part is devoted to the BERTHA model and the associated characteristic treatment for the first seconds of the blowdown, the second part presents the problems encountered for accounting for velocity difference between phases. The FLIRA treatment of the reflooding is presented in the last part: this treatment allows the calculation of the quenching front velocity

  1. Research mathematicians’ practices in selecting mathematical problems

    DEFF Research Database (Denmark)

    Misfeldt, Morten; Johansen, Mikkel Willum

    2015-01-01

    mathematicians select and pose problems and discuss to what extent our results can be used to inform, criticize, and develop educational practice at various levels. Selecting and posing problems is far from simple. In fact, it is considered hard, complex, and of crucial importance. A number of criteria...

  2. Numerical approach to the inverse convection-diffusion problem

    International Nuclear Information System (INIS)

    Yang, X-H; She, D-X; Li, J-Q

    2008-01-01

    In this paper, the inverse problem on source term identification in convection-diffusion equation is transformed into an optimization problem. To reduce the computational cost and improve computational accuracy for the optimization problem, a new algorithm, chaos real-coded hybrid-accelerating evolution algorithm (CRHAEA), is proposed, in which an initial population is generated by chaos mapping, and new chaos mutation and simplex evolution operation are used. With the shrinking of searching range, CRHAEA gradually directs to an optimal result with the excellent individuals obtained by real-coded evolution algorithm. Its convergence is analyzed. Its efficiency is demonstrated by 15 test functions. Numerical simulation shows that CRHAEA has some advantages over the real-coded accelerated evolution algorithm, the chaos algorithm and the pure random search algorithm

  3. Numerical investigation of the inverse blackbody radiation problem

    International Nuclear Information System (INIS)

    Xin Tan, Guo-zhen Yang, Ben-yuan Gu

    1994-01-01

    A numerical algorithm for the inverse blackbody radiation problem, which is the determination of the temperature distribution of a thermal radiator (TDTR) from its total radiated power spectrum (TRPS), is presented, based on the general theory of amplitude-phase retrieval. With application of this new algorithm, the ill-posed nature of the Fredholm equation of the first kind can be largely overcome and a convergent solution to high accuracy can be obtained. By incorporation of the hybrid input-output algorithm into our algorithm, the convergent process can be substantially expedited and the stagnation problem of the solution can be averted. From model calculations it is found that the new algorithm can also provide a robust reconstruction of the TDTR from the noise-corrupted data of the TRPS. Therefore the new algorithm may offer a useful approach to solving the ill-posed inverse problem. 18 refs., 9 figs

  4. A note on numerical solution to the problem of criticality

    International Nuclear Information System (INIS)

    Kyncl, J.

    2002-01-01

    The contribution deals with numerical solution to the problem of criticality for neutron transport equation by the external source iteration method. Especially, the speed of convergence is examined. It is shown that if neutron absorption in the medium considered is high and if the space region occupied by the medium is large then a slow convergence of the iterations can be expected. This expectation is confirmed by results to CB4 benchmark obtained by MCNP code. Besides the results presented some questions concerning applications of them to criticality calculations are pointed out (Author)

  5. Basic Maths Practice Problems For Dummies

    CERN Document Server

    Beveridge, Colin

    2012-01-01

    Fun, friendly coaching and all the practice you need to tackle maths problems with confidence and ease In his popular Basic Maths For Dummies, professional maths tutor Colin Beveridge proved that he could turn anyone - even the most maths-phobic person - into a natural-born number cruncher. In this book he supplies more of his unique brand of maths-made- easy coaching, plus 2,000 practice problems to help you master what you learn. Whether you're prepping for a numeracy test or an employability exam, thinking of returning to school, or you'd just like to be one of those know-it-alls who says

  6. 8th International Conference on Hyperbolic Problems : Theory, Numerics, Applications

    CERN Document Server

    Warnecke, Gerald

    2001-01-01

    The Eighth International Conference on Hyperbolic Problems - Theory, Nu­ merics, Applications, was held in Magdeburg, Germany, from February 27 to March 3, 2000. It was attended by over 220 participants from many European countries as well as Brazil, Canada, China, Georgia, India, Israel, Japan, Taiwan, und the USA. There were 12 plenary lectures, 22 further invited talks, and around 150 con­ tributed talks in parallel sessions as well as posters. The speakers in the parallel sessions were invited to provide a poster in order to enhance the dissemination of information. Hyperbolic partial differential equations describe phenomena of material or wave transport in physics, biology and engineering, especially in the field of fluid mechanics. Despite considerable progress, the mathematical theory is still strug­ gling with fundamental open problems concerning systems of such equations in multiple space dimensions. For various applications the development of accurate and efficient numerical schemes for computat...

  7. Brief report : ethical problems in research practice

    OpenAIRE

    Colnerud, Gunnel

    2013-01-01

    Most accounts of the ethical problems facing researchers across a broad spectrum of research fields come from ethicists, ethics committees, and specialists committed to the study of ethics in human research. In contrast, this study reports on the ethical questions that researchers, themselves, report facing in their everyday practice. Fifty-five Swedish researchers contributed 109 examples of ethical dilemmas, conflicts, and problems in research. They were all researchers at the postdoctoral ...

  8. Numerical implication of Riemann problem theory for fluid dynamics

    International Nuclear Information System (INIS)

    Menikoff, R.

    1988-01-01

    The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent γ, the Grueneisen coefficient Γ, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs

  9. Numerical solution of a model for a superconductor field problem

    International Nuclear Information System (INIS)

    Alsop, L.E.; Goodman, A.S.; Gustavson, F.G.; Miranker, W.L.

    1979-01-01

    A model of a magnetic field problem occurring in connection with Josephson junction devices is derived, and numerical solutions are obtained. The model is of mathematical interest, because the magnetic vector potential satisfies inhomogeneous Helmholtz equations in part of the region, i.e., the superconductors, and the Laplace equation elsewhere. Moreover, the inhomogeneities are the guage constants for the potential, which are different for each superconductor, and their magnitudes are proportional to the currents flowing in the superconductors. These constants are directly related to the self and mutual inductances of the superconducting elements in the device. The numerical solution is obtained by the iterative use of a fast Poisson solver. Chebyshev acceleration is used to reduce the number of iterations required to obtain a solution. A typical problem involves solving 100,000 simultaneous equations, which the algorithm used with this model does in 20 iterations, requiring three minutes of CPU time on an IBM VM/370/168. Excellent agreement is obtained between calculated and observed values for the inductances

  10. Multiresolution strategies for the numerical solution of optimal control problems

    Science.gov (United States)

    Jain, Sachin

    There exist many numerical techniques for solving optimal control problems but less work has been done in the field of making these algorithms run faster and more robustly. The main motivation of this work is to solve optimal control problems accurately in a fast and efficient way. Optimal control problems are often characterized by discontinuities or switchings in the control variables. One way of accurately capturing the irregularities in the solution is to use a high resolution (dense) uniform grid. This requires a large amount of computational resources both in terms of CPU time and memory. Hence, in order to accurately capture any irregularities in the solution using a few computational resources, one can refine the mesh locally in the region close to an irregularity instead of refining the mesh uniformly over the whole domain. Therefore, a novel multiresolution scheme for data compression has been designed which is shown to outperform similar data compression schemes. Specifically, we have shown that the proposed approach results in fewer grid points in the grid compared to a common multiresolution data compression scheme. The validity of the proposed mesh refinement algorithm has been verified by solving several challenging initial-boundary value problems for evolution equations in 1D. The examples have demonstrated the stability and robustness of the proposed algorithm. The algorithm adapted dynamically to any existing or emerging irregularities in the solution by automatically allocating more grid points to the region where the solution exhibited sharp features and fewer points to the region where the solution was smooth. Thereby, the computational time and memory usage has been reduced significantly, while maintaining an accuracy equivalent to the one obtained using a fine uniform mesh. Next, a direct multiresolution-based approach for solving trajectory optimization problems is developed. The original optimal control problem is transcribed into a

  11. PROBLEMS OF GENERAL PRACTICE IN RURAL CALIFORNIA

    Science.gov (United States)

    Carey, Hollis L.; Andrews, Carroll B.

    1949-01-01

    Medical care for rural populations is an important problem facing the medical profession nationally and locally. The mechanism for solution lies in the existing American Medical Association and California Medical Association committees on rural medical service and further development of “local health councils.” Additional emphasis on training of physicians for general practice is essential through medical school graduate and postgraduate periods. The problem of providing additional adequately equipped and staffed hospitals must receive much consideration. Recognizing that passiveness invites aggressive non-medical agencies to foster bureaucratic dictation inimical to the practice of medicine, the rural physician must act through medical and community organizations to correct weaknesses in the structure of medical practice. PMID:18116230

  12. Analytical and Numerical Studies of Several Fluid Mechanical Problems

    Science.gov (United States)

    Kong, D. L.

    2014-03-01

    In this thesis, three parts, each with several chapters, are respectively devoted to hydrostatic, viscous, and inertial fluids theories and applications. Involved topics include planetary, biological fluid systems, and high performance computing technology. In the hydrostatics part, the classical Maclaurin spheroids theory is generalized, for the first time, to a more realistic multi-layer model, establishing geometries of both the outer surface and the interfaces. For one of its astrophysical applications, the theory explicitly predicts physical shapes of surface and core-mantle-boundary for layered terrestrial planets, which enables the studies of some gravity problems, and the direct numerical simulations of dynamo flows in rotating planetary cores. As another application of the figure theory, the zonal flow in the deep atmosphere of Jupiter is investigated for a better understanding of the Jovian gravity field. An upper bound of gravity field distortions, especially in higher-order zonal gravitational coefficients, induced by deep zonal winds is estimated firstly. The oblate spheroidal shape of an undistorted Jupiter resulting from its fast solid body rotation is fully taken into account, which marks the most significant improvement from previous approximation based Jovian wind theories. High viscosity flows, for example Stokes flows, occur in a lot of processes involving low-speed motions in fluids. Microorganism swimming is such a typical case. A fully three dimensional analytic solution of incompressible Stokes equation is derived in the exterior domain of an arbitrarily translating and rotating prolate spheroid, which models a large family of microorganisms such as cocci bacteria. The solution is then applied to the magnetotactic bacteria swimming problem, and good consistency has been found between theoretical predictions and laboratory observations of the moving patterns of such bacteria under magnetic fields. In the analysis of dynamics of planetary

  13. Human-computer interfaces applied to numerical solution of the Plateau problem

    Science.gov (United States)

    Elias Fabris, Antonio; Soares Bandeira, Ivana; Ramos Batista, Valério

    2015-09-01

    In this work we present a code in Matlab to solve the Problem of Plateau numerically, and the code will include human-computer interface. The Problem of Plateau has applications in areas of knowledge like, for instance, Computer Graphics. The solution method will be the same one of the Surface Evolver, but the difference will be a complete graphical interface with the user. This will enable us to implement other kinds of interface like ocular mouse, voice, touch, etc. To date, Evolver does not include any graphical interface, which restricts its use by the scientific community. Specially, its use is practically impossible for most of the Physically Challenged People.

  14. Sensitivity analysis of numerical solutions for environmental fluid problems

    International Nuclear Information System (INIS)

    Tanaka, Nobuatsu; Motoyama, Yasunori

    2003-01-01

    In this study, we present a new numerical method to quantitatively analyze the error of numerical solutions by using the sensitivity analysis. If a reference case of typical parameters is one calculated with the method, no additional calculation is required to estimate the results of the other numerical parameters such as more detailed solutions. Furthermore, we can estimate the strict solution from the sensitivity analysis results and can quantitatively evaluate the reliability of the numerical solution by calculating the numerical error. (author)

  15. Electromagnetic scattering problems -Numerical issues and new experimental approaches of validation

    Energy Technology Data Exchange (ETDEWEB)

    Geise, Robert; Neubauer, Bjoern; Zimmer, Georg [University of Braunschweig, Institute for Electromagnetic Compatibility, Schleinitzstrasse 23, 38106 Braunschweig (Germany)

    2015-03-10

    Electromagnetic scattering problems, thus the question how radiated energy spreads when impinging on an object, are an essential part of wave propagation. Though the Maxwell’s differential equations as starting point, are actually quite simple,the integral formulation of an object’s boundary conditions, respectively the solution for unknown induced currents can only be solved numerically in most cases.As a timely topic of practical importance the scattering of rotating wind turbines is discussed, the numerical description of which is still based on rigorous approximations with yet unspecified accuracy. In this context the issue of validating numerical solutions is addressed, both with reference simulations but in particular with the experimental approach of scaled measurements. For the latter the idea of an incremental validation is proposed allowing a step by step validation of required new mathematical models in scattering theory.

  16. Milne, a routine for the numerical solution of Milne's problem

    Science.gov (United States)

    Rawat, Ajay; Mohankumar, N.

    2010-11-01

    The routine Milne provides accurate numerical values for the classical Milne's problem of neutron transport for the planar one speed and isotropic scattering case. The solution is based on the Case eigen-function formalism. The relevant X functions are evaluated accurately by the Double Exponential quadrature. The calculated quantities are the extrapolation distance and the scalar and the angular fluxes. Also, the H function needed in astrophysical calculations is evaluated as a byproduct. Program summaryProgram title: Milne Catalogue identifier: AEGS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGS_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.: 701 No. of bytes in distributed program, including test data, etc.: 6845 Distribution format: tar.gz Programming language: Fortran 77 Computer: PC under Linux or Windows Operating system: Ubuntu 8.04 (Kernel version 2.6.24-16-generic), Windows-XP Classification: 4.11, 21.1, 21.2 Nature of problem: The X functions are integral expressions. The convergence of these regular and Cauchy Principal Value integrals are impaired by the singularities of the integrand in the complex plane. The DE quadrature scheme tackles these singularities in a robust manner compared to the standard Gauss quadrature. Running time: The test included in the distribution takes a few seconds to run.

  17. Special boundedness properties in numerical initial value problems

    KAUST Repository

    Hundsdorfer, W.

    2011-09-21

    For Runge-Kutta methods, linear multistep methods and other classes of general linear methods much attention has been paid in the literature to important nonlinear stability properties known as total-variation-diminishing (TVD), strong stability preserving (SSP) and monotonicity. Stepsize conditions guaranteeing these properties were studied by Shu and Osher (J. Comput. Phys. 77:439-471, 1988) and in numerous subsequent papers. Unfortunately, for many useful methods it has turned out that these properties do not hold. For this reason attention has been paid in the recent literature to the related and more general properties called total-variation-bounded (TVB) and boundedness. In the present paper we focus on stepsize conditions guaranteeing boundedness properties of a special type. These boundedness properties are optimal, and distinguish themselves also from earlier boundedness results by being relevant to sublinear functionals, discrete maximum principles and preservation of nonnegativity. Moreover, the corresponding stepsize conditions are more easily verified in practical situations than the conditions for general boundedness given thus far in the literature. The theoretical results are illustrated by application to the two-step Adams-Bashforth method and a class of two-stage multistep methods. © 2011 Springer Science + Business Media B.V.

  18. Reproducibility principles, problems, practices, and prospects

    CERN Document Server

    Maasen, Sabine

    2016-01-01

    Featuring peer-reviewed contributions from noted experts in their fields of research, Reproducibility: Principles, Problems, Practices, and Prospects presents state-of-the-art approaches to reproducibility, the gold standard sound science, from multi- and interdisciplinary perspectives. Including comprehensive coverage for implementing and reflecting the norm of reproducibility in various pertinent fields of research, the book focuses on how the reproducibility of results is applied, how it may be limited, and how such limitations can be understood or even controlled in the natural sciences, computational sciences, life sciences, social sciences, and studies of science and technology. The book presents many chapters devoted to a variety of methods and techniques, as well as their epistemic and ontological underpinnings, which have been developed to safeguard reproducible research and curtail deficits and failures. The book also investigates the political, historical, and social practices that underlie repro...

  19. Practical considerations in developing numerical simulators for thermal recovery

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, Al-Ain (United Arab Emirates)

    1996-08-15

    Numerical simulation of steam injection and in-situ combustion-based oil recovery processes is of great importance in project design. Development of such numerical simulators is an on-going process, with improvements made as the process description becomes more complete, and also as better methods are devised to resolve certain numerical difficulties. This paper addresses some of the latter, and based on the author`s experience gives useful guidelines for developing more efficient numerical simulators of steam injection and in-situ combustion. The paper takes up a series of questions related to simulating thermal processes. Included are: the elimination of constraint equations at the matrix level, phase change, steam injection rate, alternative treatments of heat loss, relative permeabilities and importance of hysteresis effects, improved solutions to the grid orientation problem and other simulation problems such as potential inversion, grid block size, time-step size control and induced fractures. The points discussed in the paper should be of use to both simulator developers and users alike, and will lead to a better understanding of simulation results

  20. Numerical and analytical solutions for problems relevant for quantum computers

    International Nuclear Information System (INIS)

    Spoerl, Andreas

    2008-01-01

    Quantum computers are one of the next technological steps in modern computer science. Some of the relevant questions that arise when it comes to the implementation of quantum operations (as building blocks in a quantum algorithm) or the simulation of quantum systems are studied. Numerical results are gathered for variety of systems, e.g. NMR systems, Josephson junctions and others. To study quantum operations (e.g. the quantum fourier transform, swap operations or multiply-controlled NOT operations) on systems containing many qubits, a parallel C++ code was developed and optimised. In addition to performing high quality operations, a closer look was given to the minimal times required to implement certain quantum operations. These times represent an interesting quantity for the experimenter as well as for the mathematician. The former tries to fight dissipative effects with fast implementations, while the latter draws conclusions in the form of analytical solutions. Dissipative effects can even be included in the optimisation. The resulting solutions are relaxation and time optimised. For systems containing 3 linearly coupled spin (1)/(2) qubits, analytical solutions are known for several problems, e.g. indirect Ising couplings and trilinear operations. A further study was made to investigate whether there exists a sufficient set of criteria to identify systems with dynamics which are invertible under local operations. Finally, a full quantum algorithm to distinguish between two knots was implemented on a spin(1)/(2) system. All operations for this experiment were calculated analytically. The experimental results coincide with the theoretical expectations. (orig.)

  1. Numerical solution of singularity-perturbed two-point boundary-value problems

    International Nuclear Information System (INIS)

    Masenge, R.W.P.

    1993-07-01

    Physical processes which involve transportation of slowly diffusing substances in a fast-flowing medium are mathematically modelled by so-called singularly-perturbed second order convection diffusion differential equations in which the convective first order terms dominate over the diffusive second order terms. In general, analytical solutions of such equations are characterized by having sharp solution fronts in some sections of the interior and/or the boundary of the domain of solution. The presence of these (usually very narrow) layer regions in the solution domain makes the task of globally approximating such solutions by standard numerical techniques very difficult. In this expository paper we use a simple one-dimensional prototype problem as a vehicle for analysing the nature of the numerical approximation difficulties involved. In the sequel we present, without detailed derivation, two practical numerical schemes which succeed in varying degrees in numerically resolving the layer of the solution to the prototype problem. (author). 3 refs, 1 fig., 1 tab

  2. PREFACE: The Second International Conference on Inverse Problems: Recent Theoretical Developments and Numerical Approaches

    Science.gov (United States)

    Cheng, Jin; Hon, Yiu-Chung; Seo, Jin Keun; Yamamoto, Masahiro

    2005-01-01

    The Second International Conference on Inverse Problems: Recent Theoretical Developments and Numerical Approaches was held at Fudan University, Shanghai from 16-21 June 2004. The first conference in this series was held at the City University of Hong Kong in January 2002 and it was agreed to hold the conference once every two years in a Pan-Pacific Asian country. The next conference is scheduled to be held at Hokkaido University, Sapporo, Japan in July 2006. The purpose of this series of biennial conferences is to establish and develop constant international collaboration, especially among the Pan-Pacific Asian countries. In recent decades, interest in inverse problems has been flourishing all over the globe because of both the theoretical interest and practical requirements. In particular, in Asian countries, one is witnessing remarkable new trends of research in inverse problems as well as the participation of many young talents. Considering these trends, the second conference was organized with the chairperson Professor Li Tat-tsien (Fudan University), in order to provide forums for developing research cooperation and to promote activities in the field of inverse problems. Because solutions to inverse problems are needed in various applied fields, we entertained a total of 92 participants at the second conference and arranged various talks which ranged from mathematical analyses to solutions of concrete inverse problems in the real world. This volume contains 18 selected papers, all of which have undergone peer review. The 18 papers are classified as follows: Surveys: four papers give reviews of specific inverse problems. Theoretical aspects: six papers investigate the uniqueness, stability, and reconstruction schemes. Numerical methods: four papers devise new numerical methods and their applications to inverse problems. Solutions to applied inverse problems: four papers discuss concrete inverse problems such as scattering problems and inverse problems in

  3. A New Numerical Algorithm for Two-Point Boundary Value Problems

    OpenAIRE

    Guo, Lihua; Wu, Boying; Zhang, Dazhi

    2014-01-01

    We present a new numerical algorithm for two-point boundary value problems. We first present the exact solution in the form of series and then prove that the n-term numerical solution converges uniformly to the exact solution. Furthermore, we establish the numerical stability and error analysis. The numerical results show the effectiveness of the proposed algorithm.

  4. Study on the groundwater sustainable problem by numerical ...

    Indian Academy of Sciences (India)

    Pengpeng Zhou

    2017-10-07

    Oct 7, 2017 ... system in Zhanjiang, China, this paper presents a numerical modelling study to research groundwater sustainability of ... bility is a feasible method for solving the sus- ...... Singh A 2010 Decision support for on-farm water man-.

  5. A round robin on numerical analyses for impact problems

    International Nuclear Information System (INIS)

    Yagawa, G.; Ohtsubo, H.; Toi, Y.; Aizawa, T.; Ikushima, T.

    1984-01-01

    In this paper, two types of numerical tests are performed using several general- and special-purpose computer codes to understand dynamic behaviors of CASK for nuclear fuel shipping under the impact onto rigid floor due to the accidental fall from the height of 9 m. Discussed are the efficiency and the validity of direct time integration schemes and the effects of material and geometric nonlinearities and contact conditions on the numerical data. (orig.)

  6. Numerical solution of pipe flow problems for generalized Newtonian fluids

    International Nuclear Information System (INIS)

    Samuelsson, K.

    1993-01-01

    In this work we study the stationary laminar flow of incompressible generalized Newtonian fluids in a pipe with constant arbitrary cross-section. The resulting nonlinear boundary value problems can be written in a variational formulation and solved using finite elements and the augmented Lagrangian method. The solution of the boundary value problem is obtained by finding a saddle point of the augmented Lagrangian. In the algorithm the nonlinear part of the equations is treated locally and the solution is obtained by iteration between this nonlinear problem and a global linear problem. For the solution of the linear problem we use the SSOR preconditioned conjugate gradient method. The approximating problem is solved on a sequence of adaptively refined grids. A scheme for adjusting the value of the crucial penalization parameter of the augmented Lagrangian is proposed. Applications to pipe flow and a problem from the theory of capacities are given. (author) (34 refs.)

  7. The numerical solution of boundary value problems over an infinite domain

    International Nuclear Information System (INIS)

    Shepherd, M.; Skinner, R.

    1976-01-01

    A method is presented for the numerical solution of boundary value problems over infinite domains. An example that illustrates also the strength and accuracy of a numerical procedure for calculating Green's functions is described in detail

  8. Numerical Simulation of Liquid Sloshing Problem under Resonant Excitation

    Directory of Open Access Journals (Sweden)

    Fu-kun Gui

    2014-04-01

    Full Text Available Numerical simulations were conducted to investigate the fluid resonance in partially filled rectangular tank based on the OpenFOAM package of viscous fluid model. The numerical model was validated by the available theoretical, numerical, and experimental data. The study was mainly focused on the large amplitude sloshing motion and the corresponding impact force around the resonant condition. It was found that, for the 2D situation, the double pressure peaks happened near to the side walls around the still water level. And they were corresponding to the local free surface rising up and set-down, respectively. The impulsive loads on the tank corner with extreme magnitudes were observed as the free surface impacted the ceiling. The 3D numerical results showed that the free surface amplitudes along the side walls varied diversely, depending on the direction and frequency of the external excitation. The characteristics of the pressure around the still water level and tank ceiling were also presented. According to the computational results, it was found that the 2D numerical model can predict the impact loads near the still water level as accurately as 3D model. However, the impulsive pressure near the tank ceiling corner was remarkably underestimated.

  9. Problems with numerical techniques: Application to mid-loop operation transients

    Energy Technology Data Exchange (ETDEWEB)

    Bryce, W.M.; Lillington, J.N.

    1997-07-01

    There has been an increasing need to consider accidents at shutdown which have been shown in some PSAs to provide a significant contribution to overall risk. In the UK experience has been gained at three levels: (1) Assessment of codes against experiments; (2) Plant studies specifically for Sizewell B; and (3) Detailed review of modelling to support the plant studies for Sizewell B. The work has largely been carried out using various versions of RELAP5 and SCDAP/RELAP5. The paper details some of the problems that have needed to be addressed. It is believed by the authors that these kinds of problems are probably generic to most of the present generation system thermal-hydraulic codes for the conditions present in mid-loop transients. Thus as far as possible these problems and solutions are proposed in generic terms. The areas addressed include: condensables at low pressure, poor time step calculation detection, water packing, inadequate physical modelling, numerical heat transfer and mass errors. In general single code modifications have been proposed to solve the problems. These have been very much concerned with means of improving existing models rather than by formulating a completely new approach. They have been produced after a particular problem has arisen. Thus, and this has been borne out in practice, the danger is that when new transients are attempted, new problems arise which then also require patching.

  10. Numerical semigroups in a problem about economic incentives for consumers

    OpenAIRE

    Robles-Pérez, Aureliano M.; Rosales, José Carlos

    2016-01-01

    Motivated by a promotion to increase the number of musical downloads, we introduce the concept of $C$-incentive and show an algorithm that compute the smallest $C$-incentive containing a subset $X \\subseteq {\\mathbb N}$. On the other hand, in order to study $C$-incentives, we see that we can focus on numerical $C$-incentives. Then, we establish that the set formed by all numerical $C$-incentives is a Frobenius pseudo-variety and we show an algorithmic process to recurrently build such a pseud...

  11. Optimal stability polynomials for numerical integration of initial value problems

    KAUST Repository

    Ketcheson, David I.

    2013-01-08

    We consider the problem of finding optimally stable polynomial approximations to the exponential for application to one-step integration of initial value ordinary and partial differential equations. The objective is to find the largest stable step size and corresponding method for a given problem when the spectrum of the initial value problem is known. The problem is expressed in terms of a general least deviation feasibility problem. Its solution is obtained by a new fast, accurate, and robust algorithm based on convex optimization techniques. Global convergence of the algorithm is proven in the case that the order of approximation is one and in the case that the spectrum encloses a starlike region. Examples demonstrate the effectiveness of the proposed algorithm even when these conditions are not satisfied.

  12. Basic math and pre-algebra practice problems for dummies

    CERN Document Server

    Zegarelli, Mark

    2013-01-01

    1001 Basic Math & Pre- Algebra Practice Problems For  Dummies   Practice makes perfect-and helps deepen your understanding of basic math and pre-algebra 1001 Basic Math & Pre-Algebra Practice Problems For Dummies, with free access to online practice problems, takes you beyond the instruction and guidance offered in Basic Math & Pre-Algebra For Dummies, giving you 1,001 opportunities to practice solving problems from the major topics in your math course. You begin with some basic arithmetic practice, move on to fractions, decimals, and per

  13. Numerical Solutions of Fifth Order Boundary Value Problems Using

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    1Department of Mathematics Delta State University, Abraka, Nigeria. 2Department of ..... International Journal of Computational. Mathematics and ... Value Problems using Power Series Approximation Method.Applied. Mathematics,. 7,. 1215-.

  14. Numerical solution of fuzzy boundary value problems using Galerkin ...

    Indian Academy of Sciences (India)

    1 College of Mathematics and Statistics, Chongqing University, Chongqing 401331, China. 2 Department of ... exact solution of fuzzy first-order boundary value problems. (BVPs). ...... edge partial financial support by the Ministerio de Economıa.

  15. Optimal stability polynomials for numerical integration of initial value problems

    KAUST Repository

    Ketcheson, David I.; Ahmadia, Aron

    2013-01-01

    We consider the problem of finding optimally stable polynomial approximations to the exponential for application to one-step integration of initial value ordinary and partial differential equations. The objective is to find the largest stable step

  16. Optimal Results and Numerical Simulations for Flow Shop Scheduling Problems

    Directory of Open Access Journals (Sweden)

    Tao Ren

    2012-01-01

    Full Text Available This paper considers the m-machine flow shop problem with two objectives: makespan with release dates and total quadratic completion time, respectively. For Fm|rj|Cmax, we prove the asymptotic optimality for any dense scheduling when the problem scale is large enough. For Fm‖ΣCj2, improvement strategy with local search is presented to promote the performance of the classical SPT heuristic. At the end of the paper, simulations show the effectiveness of the improvement strategy.

  17. A numerical study of bulk evaporation and condensation problem

    International Nuclear Information System (INIS)

    Ding, Z.; Anghaie, S.

    1996-01-01

    A numerical model is developed to simulate the dynamic behavior of bulk evaporation and condensation process in an encapsulated container with internal heat generation at micro-gravity level. Thermal performance of a multi-phase system with internal heat generation is investigated. The numerical simulation yields the evolution of the bulk liquid-vapor phase change process. This includes the evolution of the liquid-vapor interface, the formation and development of the liquid film covering the side wall surface, the temperature distribution and the convection flow field. An example of such systems is a phase change nuclear fuel element which was first introduced by Ding and Anghaie with application in high temperature space nuclear power and propulsion systems

  18. On numerical-analytic techniques for boundary value problems

    Czech Academy of Sciences Publication Activity Database

    Rontó, András; Rontó, M.; Shchobak, N.

    2012-01-01

    Roč. 12, č. 3 (2012), s. 5-10 ISSN 1335-8243 Institutional support: RVO:67985840 Keywords : numerical-analytic method * periodic successive approximations * Lyapunov-Schmidt method Subject RIV: BA - General Mathematics http://www.degruyter.com/view/j/aeei.2012.12.issue-3/v10198-012-0035-1/v10198-012-0035-1.xml?format=INT

  19. Optimization problems with equilibrium constraints and their numerical solution

    Czech Academy of Sciences Publication Activity Database

    Kočvara, Michal; Outrata, Jiří

    Roč. 101 , č. 1 (2004), s. 119-149 ISSN 0025-5610 R&D Projects: GA AV ČR IAA1075005 Grant - others:BMBF(DE) 03ZOM3ER Institutional research plan: CEZ:AV0Z1075907 Keywords : optimization problems * MPEC * MPCC Subject RIV: BA - General Mathematics Impact factor: 1.016, year: 2004

  20. Numerical Problems and Agent-Based Models for a Mass Transfer Course

    Science.gov (United States)

    Murthi, Manohar; Shea, Lonnie D.; Snurr, Randall Q.

    2009-01-01

    Problems requiring numerical solutions of differential equations or the use of agent-based modeling are presented for use in a course on mass transfer. These problems were solved using the popular technical computing language MATLABTM. Students were introduced to MATLAB via a problem with an analytical solution. A more complex problem to which no…

  1. Research Mathematicians' Practices in Selecting Mathematical Problems

    Science.gov (United States)

    Misfeldt, Morten; Johansen, Mikkel Willum

    2015-01-01

    Developing abilities to create, inquire into, qualify, and choose among mathematical problems is an important educational goal. In this paper, we elucidate how mathematicians work with mathematical problems in order to understand this mathematical process. More specifically, we investigate how mathematicians select and pose problems and discuss to…

  2. [Parenting practices and internalizing and externalizing problems in Spanish adolescents].

    Science.gov (United States)

    García Linares, Ma Cruz; Cerezo Rusillo, Ma Teresa; de la Torre Cruz, Manuel Jesús; de la Villa Carpio Fernández, Ma; Casanova Arias, Pedro Félix

    2011-11-01

    The goal of this study was to analyze the relationship between parenting practices and internalizing and externalizing problems presented by a group of adolescents according to their gender. Four hundred and sixty-nine secondary school students (aged between 12 and 18) participated in this study. The adolescents presented differences in perception of the educational practices of both parents as a function of their gender. Negative parenting practices were positively related to adolescents' internalizing and externalizing problems, whereas positive practices were negatively related to externalizing problems. Moreover, differences between boys and girls were found in predictor variables of problems, and the predictive power of the variables was higher for externalizing problems.

  3. The Numerical Solution of the Equilibrium Problem for a Stretchable Elastic Beam

    Science.gov (United States)

    Mehdiyeva, G. Y.; Aliyev, A. Y.

    2017-08-01

    The boundary value problem under consideration describes the equilibrium of an elastic beam that is stretched or contracted by specified forces. The left end of the beam is free of load, and the right end is rigidly lapped. To solve the problem numerically, an appropriate difference problem is constructed. Solving the difference problem, we obtain an approximate solution of the problem. We estimate the approximate solution of the stated problem.

  4. Numerical solutions to critical problem of reflected cylindrical reactor

    International Nuclear Information System (INIS)

    Horie, Junnosuke

    1977-01-01

    The multi-region critical problem can be transformed into an eigenvalue problem in the classical sense by using the method of Kuscer and Corngold and of Wing. This transformation is applied to derive a variational formulation for a reflected reactor. An approximate critical value of the multiplying factor is determined by maximizing the Rayleigh quotient for radially and totally reflected cylindrical reactors. It is shown that this approximate critical value is an upper bound of the true critical value. From the facts that the operator is self-adjoint and the eigenfunction is positive, an expression is derived for the upper and lower bounds of the true eigenvalue, by making use of the approximate distribution. The difference of the upper and lower bounds is an uncertainty of the presumption of the true critical value. It is found that we can compute the bounds to any required precision. The narrow bounds are calculated for two radially and one totally reflected cylindrical reactors. (auth.)

  5. Numerical solution of Stefan's problem to heterogeneous materials

    International Nuclear Information System (INIS)

    Basombrio, F.G.

    1996-01-01

    We present an extension of the methodology developed by R.H. Nochetto et al. to solve the Stefan problem, to situations for which the physical properties are dependent on the spatial point (thermic non-homogeneous materials). In this report, the theoretical and computational aspects are described. With the purpose of showing the performance of programme FASES2, two illustrative examples are included. (author). 6 refs., 2 figs

  6. Numerical analysis of Sakiadis flow problem considering Maxwell nanofluid

    Directory of Open Access Journals (Sweden)

    Mustafa Meraj

    2017-01-01

    Full Text Available This article investigates the flow of Maxwell nanofluid over a moving plate in a calm fluid. Novel aspects of Brownian motion and thermophoresis are taken into consideration. Revised model for passive control of nanoparticle volume fraction at the plate is used in this study. The formulated differential system is solved numerically by employing shooting approach together with fourth-fifth-order-Runge-Kutta integration procedure and Newton’s method. The solutions are greatly influenced with the variation of embedded parameters which include the local Deborah number, the Brownian motion parameter, the thermophoresis parameter, the Prandtl number, and the Schmidt number. We found that the variation in velocity distribution with an increase in local Deborah number is non-monotonic. Moreover, the reduced Nusselt number has a linear and direct relationship with the local Deborah number.

  7. A strong shock tube problem calculated by different numerical schemes

    Science.gov (United States)

    Lee, Wen Ho; Clancy, Sean P.

    1996-05-01

    Calculated results are presented for the solution of a very strong shock tube problem on a coarse mesh using (1) MESA code, (2) UNICORN code, (3) Schulz hydro, and (4) modified TVD scheme. The first two codes are written in Eulerian coordinates, whereas methods (3) and (4) are in Lagrangian coordinates. MESA and UNICORN codes are both of second order and use different monotonic advection method to avoid the Gibbs phenomena. Code (3) uses typical artificial viscosity for inviscid flow, whereas code (4) uses a modified TVD scheme. The test problem is a strong shock tube problem with a pressure ratio of 109 and density ratio of 103 in an ideal gas. For no mass-matching case, Schulz hydro is better than TVD scheme. In the case of mass-matching, there is no difference between them. MESA and UNICORN results are nearly the same. However, the computed positions such as the contact discontinuity (i.e. the material interface) are not as accurate as the Lagrangian methods.

  8. A strong shock tube problem calculated by different numerical schemes

    International Nuclear Information System (INIS)

    Lee, W.H.; Clancy, S.P.

    1996-01-01

    Calculated results are presented for the solution of a very strong shock tube problem on a coarse mesh using (1) MESA code, (2) UNICORN code, (3) Schulz hydro, and (4) modified TVD scheme. The first two codes are written in Eulerian coordinates, whereas methods (3) and (4) are in Lagrangian coordinates. MESA and UNICORN codes are both of second order and use different monotonic advection method to avoid the Gibbs phenomena. Code (3) uses typical artificial viscosity for inviscid flow, whereas code (4) uses a modified TVD scheme. The test problem is a strong shock tube problem with a pressure ratio of 10 9 and density ratio of 10 3 in an ideal gas. For no mass-matching case, Schulz hydro is better than TVD scheme. In the case of mass-matching, there is no difference between them. MESA and UNICORN results are nearly the same. However, the computed positions such as the contact discontinuity (i.e. the material interface) are not as accurate as the Lagrangian methods. copyright 1996 American Institute of Physics

  9. Numerical relativity

    International Nuclear Information System (INIS)

    Piran, T.

    1982-01-01

    There are many recent developments in numerical relativity, but there remain important unsolved theoretical and practical problems. The author reviews existing numerical approaches to solution of the exact Einstein equations. A framework for classification and comparison of different numerical schemes is presented. Recent numerical codes are compared using this framework. The discussion focuses on new developments and on currently open questions, excluding a review of numerical techniques. (Auth.)

  10. On the numerical treatment of problems in atmospheric chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Aro, Colin J. [Univ. of California, Davis, CA (United States)

    1995-09-01

    Atmospheric chemical-radiative-transport (CRT) models are vital in performing research on atmospheric chemical change. Even with the enormous computing capability delivered by massively parallel systems, extended three dimensional CRT simulations are still not computationally feasible. The major obstacle in a CRT model is the nonlinear ODE system describing the chemical kinetics in the model. These ODE systems are usually very stiff and account for anywhere from 75% to 90% of the CPU time required to run a CRT model. In this study, a simple explicit class of time stepping method is developed and demonstrated to be useful in treating chemical ODE systems without the use of a Jacobian matrix. These methods, called preconditioned time differencing methods, are tested on small mathematically idealized problems, box model problems, and full 2-D and 3-D CRT models. The methods are found to be both fast and memory efficient. Studies are performed on both vector and parallel systems. The preconditioned time differencing methods are established as a viable alternative to the more common backward differentiation formulas in terms of CPU speed across architectural platforms.

  11. Numerical solution of an inverse 2D Cauchy problem connected with the Helmholtz equation

    International Nuclear Information System (INIS)

    Wei, T; Qin, H H; Shi, R

    2008-01-01

    In this paper, the Cauchy problem for the Helmholtz equation is investigated. By Green's formulation, the problem can be transformed into a moment problem. Then we propose a numerical algorithm for obtaining an approximate solution to the Neumann data on the unspecified boundary. Error estimate and convergence analysis have also been given. Finally, we present numerical results for several examples and show the effectiveness of the proposed method

  12. Topological insulators and C*-algebras: Theory and numerical practice

    International Nuclear Information System (INIS)

    Hastings, Matthew B.; Loring, Terry A.

    2011-01-01

    Research highlights: → We classify topological insulators using C* algebras. → We present new K-theory invariants. → We develop efficient numerical algorithms based on this technique. → We observe unexpected quantum phase transitions using our algorithm. - Abstract: We apply ideas from C*-algebra to the study of disordered topological insulators. We extract certain almost commuting matrices from the free Fermi Hamiltonian, describing band projected coordinate matrices. By considering topological obstructions to approximating these matrices by exactly commuting matrices, we are able to compute invariants quantifying different topological phases. We generalize previous two dimensional results to higher dimensions; we give a general expression for the topological invariants for arbitrary dimension and several symmetry classes, including chiral symmetry classes, and we present a detailed K-theory treatment of this expression for time reversal invariant three dimensional systems. We can use these results to show non-existence of localized Wannier functions for these systems. We use this approach to calculate the index for time-reversal invariant systems with spin-orbit scattering in three dimensions, on sizes up to 12 3 , averaging over a large number of samples. The results show an interesting separation between the localization transition and the point at which the average index (which can be viewed as an 'order parameter' for the topological insulator) begins to fluctuate from sample to sample, implying the existence of an unsuspected quantum phase transition separating two different delocalized phases in this system. One of the particular advantages of the C*-algebraic technique that we present is that it is significantly faster in practice than other methods of computing the index, allowing the study of larger systems. In this paper, we present a detailed discussion of numerical implementation of our method.

  13. Problem-Based Composition: The Practical Side

    Science.gov (United States)

    Beckelhimer, Lisa; Hundemer, Ronald; Sharp, Judith; Zipfel, William

    2007-01-01

    For several years a number of instructors at the University of Cincinnati have experimented with the concept of problem-based learning (PBL) in their composition courses. The concept, rooted as it is in Socratic method and the hands-on problem-solving advocated by John Dewey, is not new, and though some of its applications may call for adjustments…

  14. Numerical Methods for Forward and Inverse Problems in Discontinuous Media

    Energy Technology Data Exchange (ETDEWEB)

    Chartier, Timothy P.

    2011-03-08

    The research emphasis under this grant's funding is in the area of algebraic multigrid methods. The research has two main branches: 1) exploring interdisciplinary applications in which algebraic multigrid can make an impact and 2) extending the scope of algebraic multigrid methods with algorithmic improvements that are based in strong analysis.The work in interdisciplinary applications falls primarily in the field of biomedical imaging. Work under this grant demonstrated the effectiveness and robustness of multigrid for solving linear systems that result from highly heterogeneous finite element method models of the human head. The results in this work also give promise to medical advances possible with software that may be developed. Research to extend the scope of algebraic multigrid has been focused in several areas. In collaboration with researchers at the University of Colorado, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory, the PI developed an adaptive multigrid with subcycling via complementary grids. This method has very cheap computing costs per iterate and is showing promise as a preconditioner for conjugate gradient. Recent work with Los Alamos National Laboratory concentrates on developing algorithms that take advantage of the recent advances in adaptive multigrid research. The results of the various efforts in this research could ultimately have direct use and impact to researchers for a wide variety of applications, including, astrophysics, neuroscience, contaminant transport in porous media, bi-domain heart modeling, modeling of tumor growth, and flow in heterogeneous porous media. This work has already led to basic advances in computational mathematics and numerical linear algebra and will continue to do so into the future.

  15. Problem-Oriented Requirements in Practice

    DEFF Research Database (Denmark)

    Lauesen, Søren

    2018-01-01

    [Context and motivation] Traditional requirements describe what the system shall do. This gives suppliers little freedom to use what they have already. In contrast, problem-oriented requirements describe the customer’s demands: what he wants to use the system for and which problems he wants...... to remove. The supplier specifies how his system will deal with these issues. The author developed the problem-oriented approach in 2007 on request from the Danish Government, and named it SL-07. [Question/problem] SL-07 has been used in many projects – usually with success. However, we had no detailed re......¬ports of the effects. [Princi¬pal ideas/results] This paper is a case study of SL-07 in acquisition of a complex case-management system. The author wrote the requirements and managed the supplier selection. Next, he was asked to run the entire acquisition project, although he was a novice project manager. Some...

  16. Prevalence of alcohol problems in general practice

    DEFF Research Database (Denmark)

    Rambaldi, A; Todisco, N; Gluud, C

    1996-01-01

    The Michigan Alcoholism Screening Test (MAST) and the response to a question about heavy alcohol consumption were used to assess the prevalence of alcohol problems in consecutive patients (77 males and 46 females) consulting a general practitioner in an urban area in the South of Italy (Castellam...... as a screening question in order to detect alcohol problems and give advice regarding reduction of alcohol consumption....

  17. The initial value problem as it relates to numerical relativity.

    Science.gov (United States)

    Tichy, Wolfgang

    2017-02-01

    Spacetime is foliated by spatial hypersurfaces in the 3+1 split of general relativity. The initial value problem then consists of specifying initial data for all fields on one such a spatial hypersurface, such that the subsequent evolution forward in time is fully determined. On each hypersurface the 3-metric and extrinsic curvature describe the geometry. Together with matter fields such as fluid velocity, energy density and rest mass density, the 3-metric and extrinsic curvature then constitute the initial data. There is a lot of freedom in choosing such initial data. This freedom corresponds to the physical state of the system at the initial time. At the same time the initial data have to satisfy the Hamiltonian and momentum constraint equations of general relativity and can thus not be chosen completely freely. We discuss the conformal transverse traceless and conformal thin sandwich decompositions that are commonly used in the construction of constraint satisfying initial data. These decompositions allow us to specify certain free data that describe the physical nature of the system. The remaining metric fields are then determined by solving elliptic equations derived from the constraint equations. We describe initial data for single black holes and single neutron stars, and how we can use conformal decompositions to construct initial data for binaries made up of black holes or neutron stars. Orbiting binaries will emit gravitational radiation and thus lose energy. Since the emitted radiation tends to circularize the orbits over time, one can thus expect that the objects in a typical binary move on almost circular orbits with slowly shrinking radii. This leads us to the concept of quasi-equilibrium, which essentially assumes that time derivatives are negligible in corotating coordinates for binaries on almost circular orbits. We review how quasi-equilibrium assumptions can be used to make physically well motivated approximations that simplify the elliptic

  18. Use of Green's functions in the numerical solution of two-point boundary value problems

    Science.gov (United States)

    Gallaher, L. J.; Perlin, I. E.

    1974-01-01

    This study investigates the use of Green's functions in the numerical solution of the two-point boundary value problem. The first part deals with the role of the Green's function in solving both linear and nonlinear second order ordinary differential equations with boundary conditions and systems of such equations. The second part describes procedures for numerical construction of Green's functions and considers briefly the conditions for their existence. Finally, there is a description of some numerical experiments using nonlinear problems for which the known existence, uniqueness or convergence theorems do not apply. Examples here include some problems in finding rendezvous orbits of the restricted three body system.

  19. Finite element circuit theory of the numerical code EDDYMULT for solving eddy current problems in a multi-torus system

    International Nuclear Information System (INIS)

    Nakamura, Yukiharu; Ozeki, Takahisa

    1986-07-01

    The finite element circuit theory is extended to the general eddy current problem in a multi-torus system, which consists of various torus conductors and axisymmetric coil systems. The numerical procedures are devised to avoid practical restrictions of computer storage and computing time, that is, the reduction technique of eddy current eigen modes to save storage and the introduction of shape function into the double area integral of mode coupling to save time. The numerical code EDDYMULT based on the theory is developed to use in designing tokamak device from the viewpoints of the evaluation of electromagnetic loading on the device components and the control analysis of tokamak equilibrium. (author)

  20. A new numerical approach for uniquely solvable exterior Riemann-Hilbert problem on region with corners

    Science.gov (United States)

    Zamzamir, Zamzana; Murid, Ali H. M.; Ismail, Munira

    2014-06-01

    Numerical solution for uniquely solvable exterior Riemann-Hilbert problem on region with corners at offcorner points has been explored by discretizing the related integral equation using Picard iteration method without any modifications to the left-hand side (LHS) and right-hand side (RHS) of the integral equation. Numerical errors for all iterations are converge to the required solution. However, for certain problems, it gives lower accuracy. Hence, this paper presents a new numerical approach for the problem by treating the generalized Neumann kernel at LHS and the function at RHS of the integral equation. Due to the existence of the corner points, Gaussian quadrature is employed which avoids the corner points during numerical integration. Numerical example on a test region is presented to demonstrate the effectiveness of this formulation.

  1. External Science Courses: The Practicals Problem.

    Science.gov (United States)

    Kember, David

    1982-01-01

    Describes three methods for offering practical work for external science courses: residential sessions on campus, local centers, and use of home laboratory kits. The advantages and disadvantages of each are discussed and examples of each in operation are given. A 21-item bibliography is provided. (EAO)

  2. A Numerical Framework for Self-Similar Problems in Plasticity: Indentation in Single Crystals

    DEFF Research Database (Denmark)

    Juul, Kristian Jørgensen; Niordson, Christian Frithiof; Nielsen, Kim Lau

    A new numerical framework specialized for analyzing self-similar problems in plasticity is developed. Self-similarity in plasticity is encountered in a number of different problems such as stationary cracks, void growth, indentation etc. To date, such problems are handled by traditional Lagrangian...... procedures that may be associated with severe numerical difficulties relating to sufficient discretization, moving contact points, etc. In the present work, self-similarity is exploited to construct the numerical framework that offers a simple and efficient method to handle self-similar problems in history...... numerical simulations [3] when possible. To mimic the condition for the analytical predictions, the wedge indenter is considered nearly flat and the material is perfectly plastic with a very low yield strain. Under these conditions, [1][2] proved analytically the existence of discontinuities in the slip...

  3. A numerical solution of a singular boundary value problem arising in boundary layer theory.

    Science.gov (United States)

    Hu, Jiancheng

    2016-01-01

    In this paper, a second-order nonlinear singular boundary value problem is presented, which is equivalent to the well-known Falkner-Skan equation. And the one-dimensional third-order boundary value problem on interval [Formula: see text] is equivalently transformed into a second-order boundary value problem on finite interval [Formula: see text]. The finite difference method is utilized to solve the singular boundary value problem, in which the amount of computational effort is significantly less than the other numerical methods. The numerical solutions obtained by the finite difference method are in agreement with those obtained by previous authors.

  4. Vectorization and parallelization of a numerical scheme for 3D global atmospheric transport-chemistry problems

    NARCIS (Netherlands)

    E.J. Spee (Edwin); P.M. de Zeeuw (Paul); J.G. Verwer (Jan); J.G. Blom (Joke); W. Hundsdorfer (Willem)

    1996-01-01

    textabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents

  5. Problem-Based Instructional Strategy and Numerical Ability as Determinants of Senior Secondary Achievement in Mathematics

    Science.gov (United States)

    Badru, Ademola K.

    2016-01-01

    The study investigated Problem-based Instructional Strategy and Numerical ability as determinants of Senior Secondary Achievement in Mathematics. This study used 4 x 2 x 2 non-randomised control group Pretest-Posttest Quasi-experimental Factorial design. It consisted of two independent variables (treatment and Numerical ability) and one moderating…

  6. A review of recent advances in numerical modelling of local scour problems

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu

    2014-01-01

    A review is presented of recent advances in numerical modelling of local scour problems. The review is organized in five sections: Highlights of numerical modelling of local scour; Influence of turbulence on scour; Backfilling of scour holes; Scour around complex structures; and Scour protection ...

  7. METHODOLOGICAL PROBLEMS OF PRACTICAL RADIOGENIC RISK ESTIMATIONS

    Directory of Open Access Journals (Sweden)

    A. Т. Gubin

    2014-01-01

    Full Text Available Mathematical ratios were established according to the description of the calculation procedure for the values of the nominal risk coefficient given in the ICRP Recommendations 2007. It is shown that the lifetime radiogenic risk is a linear functional from the distribution of the dose in time with a multiplier descending with age. As a consequence, application of the nominal risk coefficient in the risk calculations is justified in the case when prolonged exposure is practically evenly distributed in time, and gives a significant deviation at a single exposure. When using the additive model of radiogenic risk proposed in the UNSCEAR Report 2006 for solid cancers, this factor is almost linearly decreasing with the age, which is convenient for its practical application.

  8. Numerical solution of the problems for plates on partial internal supports of complicated configurations

    International Nuclear Information System (INIS)

    Quang A, Dang; Hai, Truong Ha

    2014-01-01

    Very recently in the work S imple Iterative Method for Solving Problems for Plates with Partial Internal Supports, Journal of Engineering Mathematics, DOI: 10.1007/s10665-013-9652-7 (in press) , we proposed a numerical method for solving some problems of plates on one and two line partial internal supports (LPIS). In the essence they are problems with strongly mixed boundary conditions for biharmonic equation. Using this method we reduced the problems to a sequence of boundary value problems for the Poisson equation with weakly mixed boundary conditions, which are easily solved numerically. The advantages of the method over other ones were shown. In this paper we apply the method to plates on internal supports of more complicated configurations. Namely, we consider the case of three LPIS and the case of the cross support. The convergence of the method is established theoretically and its efficiency is confirmed on numerical experiments

  9. Numerical

    Directory of Open Access Journals (Sweden)

    M. Boumaza

    2015-07-01

    Full Text Available Transient convection heat transfer is of fundamental interest in many industrial and environmental situations, as well as in electronic devices and security of energy systems. Transient fluid flow problems are among the more difficult to analyze and yet are very often encountered in modern day technology. The main objective of this research project is to carry out a theoretical and numerical analysis of transient convective heat transfer in vertical flows, when the thermal field is due to different kinds of variation, in time and space of some boundary conditions, such as wall temperature or wall heat flux. This is achieved by the development of a mathematical model and its resolution by suitable numerical methods, as well as performing various sensitivity analyses. These objectives are achieved through a theoretical investigation of the effects of wall and fluid axial conduction, physical properties and heat capacity of the pipe wall on the transient downward mixed convection in a circular duct experiencing a sudden change in the applied heat flux on the outside surface of a central zone.

  10. Mechanism of indictment. Problems, theory and practice

    Directory of Open Access Journals (Sweden)

    Timur A. Gumerov

    2017-03-01

    Full Text Available Objective to determine the stages of the mechanism of pretrial adoption of indictment to identify the main mistakes made when making an indictment and offer ways of their elimination. Methods logical comparativelegal normativelogical and statistical as well as the method of complex study of phenomena and processes of legal reality. Results within the framework of the proposed mechanism of prejudicial indictment adoption and basing on the analysis of 45 indictments and their receipts in various categories of cases the common errors were identified of the subjects of criminal procedural law involved in the mechanism of indictment preparation and adoption. These include the presence of smudges underlined places and erasures in the text of the indictment the discrepancy between the indictment and the charges set out in the resolution on impleading of a defendant confusion referred to the approval of the indictment by the head of the investigative body etc. Therefore it is proposed to supplement Part 1 of Article 39 of the Russian CriminalProcedural Code with paragraph 9.1. quotTo agree on the indictment after its signing by the investigatorquot to extend the term of preliminary investigation and to assign additional days for the indictment approval to put into practice the meeting of all actors of the criminal process involved in the mechanism of the indictment adoption in order to analyze the quality and completeness of the investigation typical investigation errors and violations of criminalprocedural legislation. Scientific novelty as a result of the study frequent errors arising from the adoption of the indictment were identified occurring since the end of the preliminary investigation with indictment till the adoption of the criminal case with the indictment by the court suggestions on avoiding them were formulated. Practical significance the main provisions and conclusions of the article can be used in scientific and teaching activities in

  11. A Direct Numerical Reconstruction Algorithm for the 3D Calderón Problem

    DEFF Research Database (Denmark)

    Delbary, Fabrice; Hansen, Per Christian; Knudsen, Kim

    2011-01-01

    In three dimensions Calderón's problem was addressed and solved in theory in the 1980s in a series of papers, but only recently the numerical implementation of the algorithm was initiated. The main ingredients in the solution of the problem are complex geometrical optics solutions to the conducti...

  12. Numerical solutions of a three-point boundary value problem with an ...

    African Journals Online (AJOL)

    Numerical solutions of a three-point boundary value problem with an integral condition for a third-order partial differential equation by using Laplace transform method Solutions numeriques d'un probleme pour une classe d'equations differentielles d'ordr.

  13. To the development of numerical methods in problems of radiation transport

    International Nuclear Information System (INIS)

    Germogenova, T.A.

    1990-01-01

    Review of studies on the development of numerical methods and the discrete ordinate method in particular, used for solution of radiation protection physics problems is given. Consideration is given to the problems, which arise when calculating fields of penetrating radiation and when studying processes of charged-particle transport and cascade processes, generated by high-energy primary radiation

  14. Pre-calculus 1,001 practice problems for dummies

    CERN Document Server

    Sterling, Mary Jane; Sterling

    2014-01-01

    Prepare for calculus the smart way, with customizable pre-calculus practice 1,001 Pre-Calculus Practice Problems For Dummies offers 1,001 opportunities to gain confidence in your math skills. Much more than a workbook, this study aid provides pre-calculus problems ranked from easy to advanced, with detailed explanations and step-by-step solutions for each one. The companion website gives you free online access to all 1,001 practice problems and solutions, and you can track your progress and ID where you should focus your study time. Accessible on the go by smart phone, tablet, o

  15. Development of a set of benchmark problems to verify numerical methods for solving burnup equations

    International Nuclear Information System (INIS)

    Lago, Daniel; Rahnema, Farzad

    2017-01-01

    Highlights: • Description transmutation chain benchmark problems. • Problems for validating numerical methods for solving burnup equations. • Analytical solutions for the burnup equations. • Numerical solutions for the burnup equations. - Abstract: A comprehensive set of transmutation chain benchmark problems for numerically validating methods for solving burnup equations was created. These benchmark problems were designed to challenge both traditional and modern numerical methods used to solve the complex set of ordinary differential equations used for tracking the change in nuclide concentrations over time due to nuclear phenomena. Given the development of most burnup solvers is done for the purpose of coupling with an established transport solution method, these problems provide a useful resource in testing and validating the burnup equation solver before coupling for use in a lattice or core depletion code. All the relevant parameters for each benchmark problem are described. Results are also provided in the form of reference solutions generated by the Mathematica tool, as well as additional numerical results from MATLAB.

  16. Efficient Numerical Solution of Coupled Radial Differential Equations in Multichannel Scattering Problems

    International Nuclear Information System (INIS)

    Houfek, Karel

    2008-01-01

    Numerical solution of coupled radial differential equations which are encountered in multichannel scattering problems is presented. Numerical approach is based on the combination of the exterior complex scaling method and the finite-elements method with the discrete variable representation. This method can be used not only to solve multichannel scattering problem but also to find bound states and resonance positions and widths directly by diagonalization of the corresponding complex scaled Hamiltonian. Efficiency and accuracy of this method is demonstrated on an analytically solvable two-channel problem.

  17. Nonlinear reaction-diffusion equations with delay: some theorems, test problems, exact and numerical solutions

    Science.gov (United States)

    Polyanin, A. D.; Sorokin, V. G.

    2017-12-01

    The paper deals with nonlinear reaction-diffusion equations with one or several delays. We formulate theorems that allow constructing exact solutions for some classes of these equations, which depend on several arbitrary functions. Examples of application of these theorems for obtaining new exact solutions in elementary functions are provided. We state basic principles of construction, selection, and use of test problems for nonlinear partial differential equations with delay. Some test problems which can be suitable for estimating accuracy of approximate analytical and numerical methods of solving reaction-diffusion equations with delay are presented. Some examples of numerical solutions of nonlinear test problems with delay are considered.

  18. A numerical method for two-dimensional anisotropic transport problem in cylindrical geometry

    International Nuclear Information System (INIS)

    Du Mingsheng; Feng Tiekai; Fu Lianxiang; Cao Changshu; Liu Yulan

    1988-01-01

    The authors deal with the triangular mesh-discontinuous finite element method for solving the time-dependent anisotropic neutron transport problem in two-dimensional cylindrical geometry. A prior estimate of the numerical solution is given. Stability is proved. The authors have computed a two dimensional anisotropic neutron transport problem and a Tungsten-Carbide critical assembly problem by using the numerical method. In comparision with DSN method and the experimental results obtained by others both at home and abroad, the method is satisfactory

  19. Quality factor: conceptual problems and practical solutions

    International Nuclear Information System (INIS)

    Dennis, J.A.

    1988-01-01

    In the past ten years a growing divide has become apparent between the dosimetric concepts designed to provide measures of stochastic risks and those designed for the measurement and control of exposures to radiation. Those designed to provide estimates of risk, e.g. effective dose equivalent, might need to be further refined to incorporate the latest scientific beliefs and evidence about the dependence on radiation quality and dose rate as well as on age and sex. Both animal and human evidence strongly supports a belief that different tissues and different types of neoplasm will have different dependencies on radiation quality and dose rate. For practical purposes of risk estimation it is necessary to select the same values for all human neoplasms. There are reasons for using life shortening in animals as a basis for this purpose, but the data for the dependence on the whole range of radiation qualities is meagre. To provide some stability for the new concepts of measurement and calibration it may be better to accommodate changing perceptions on radiation risks by specifying different levels of exposure for different types of radiation without changing the current quality factors for the measurement quantities. (author)

  20. Relations between transfer matrices and numerical stability analysis to avoid the $\\Omega d$ problem

    OpenAIRE

    Pérez-Álvarez, R.; Pernas-Salomón, R.; Velasco, V. R.

    2015-01-01

    The transfer matrix method is usually employed to study problems described by $N$ equations of matrix Sturm-Liouville (MSL) kind. In some cases a numerical degradation (the so called $\\Omega d$ problem) appears thus impairing the performance of the method. We present here a procedure that can overcome this problem in the case of multilayer systems having piecewise constant coefficients. This is performed by studying the relations between the associated transfer matrix and other transfer matri...

  1. Optimality conditions for the numerical solution of optimization problems with PDE constraints :

    Energy Technology Data Exchange (ETDEWEB)

    Aguilo Valentin, Miguel Alejandro; Ridzal, Denis

    2014-03-01

    A theoretical framework for the numerical solution of partial di erential equation (PDE) constrained optimization problems is presented in this report. This theoretical framework embodies the fundamental infrastructure required to e ciently implement and solve this class of problems. Detail derivations of the optimality conditions required to accurately solve several parameter identi cation and optimal control problems are also provided in this report. This will allow the reader to further understand how the theoretical abstraction presented in this report translates to the application.

  2. Problem solving therapy - use and effectiveness in general practice.

    Science.gov (United States)

    Pierce, David

    2012-09-01

    Problem solving therapy (PST) is one of the focused psychological strategies supported by Medicare for use by appropriately trained general practitioners. This article reviews the evidence base for PST and its use in the general practice setting. Problem solving therapy involves patients learning or reactivating problem solving skills. These skills can then be applied to specific life problems associated with psychological and somatic symptoms. Problem solving therapy is suitable for use in general practice for patients experiencing common mental health conditions and has been shown to be as effective in the treatment of depression as antidepressants. Problem solving therapy involves a series of sequential stages. The clinician assists the patient to develop new empowering skills, and then supports them to work through the stages of therapy to determine and implement the solution selected by the patient. Many experienced GPs will identify their own existing problem solving skills. Learning about PST may involve refining and focusing these skills.

  3. Solution of the main problem of the lunar physical libration by a numerical method

    Science.gov (United States)

    Zagidullin, Arthur; Petrova, Natalia; Nefediev, Yurii

    2016-10-01

    Series of the lunar programs requires highly accurate ephemeris of the Moon at any given time. In the light of the new requirements on the accuracy the requirements to the lunar physical libration theory increase.At the Kazan University there is the experience of constructing the lunar rotation theory in the analytical approach. Analytical theory is very informative in terms of the interpretation of the observed data, but inferior to the accuracy of numerical theories. The most accurate numerical ephemeris of the Moon is by far the ephemeris DE430 / 431 built in the USA. It takes into account a large number of subtle effects both in external perturbations of the Moon, and in its internal structure. Before the Russian scientists the task is to create its own numerical theory that would be consistent with the American ephemeris. On the other hand, even the practical application of the american ephemeris requires a deep understanding of the principles of their construction and the intelligent application.As the first step, we constructed a theory in the framework of the main problem. Because we compare our theory with the analytical theory of Petrova (1996), all the constants and the theory of orbital motion are taken identical to the analytical theory. The maximum precision, which the model can provide is 0.01 seconds of arc, which is insufficient to meet the accuracy of modern observations, but this model provides the necessary basis for further development.We have constructed the system of the libration equations, for which the numerical integrator was developed. The internal accuracy of the software integrator is several nanoseconds. When compared with the data of Petrova the differences of order of 1 second are observed at the resonant frequencies. The reason, we believe, in the inaccuracy of the analytical theory. We carried out a comparison with the Eroshkin's data [2], which gave satisfactory agreement, and with Rambaux data. In the latter case, as expected

  4. Digital dice computational solutions to practical probability problems

    CERN Document Server

    Nahin, Paul J

    2013-01-01

    Some probability problems are so difficult that they stump the smartest mathematicians. But even the hardest of these problems can often be solved with a computer and a Monte Carlo simulation, in which a random-number generator simulates a physical process, such as a million rolls of a pair of dice. This is what Digital Dice is all about: how to get numerical answers to difficult probability problems without having to solve complicated mathematical equations. Popular-math writer Paul Nahin challenges readers to solve twenty-one difficult but fun problems, from determining the

  5. Practical integrated simulation systems for coupled numerical simulations in parallel

    Energy Technology Data Exchange (ETDEWEB)

    Osamu, Hazama; Zhihong, Guo [Japan Atomic Energy Research Inst., Centre for Promotion of Computational Science and Engineering, Tokyo (Japan)

    2003-07-01

    In order for the numerical simulations to reflect 'real-world' phenomena and occurrences, incorporation of multidisciplinary and multi-physics simulations considering various physical models and factors are becoming essential. However, there still exist many obstacles which inhibit such numerical simulations. For example, it is still difficult in many instances to develop satisfactory software packages which allow for such coupled simulations and such simulations will require more computational resources. A precise multi-physics simulation today will require parallel processing which again makes it a complicated process. Under the international cooperative efforts between CCSE/JAERI and Fraunhofer SCAI, a German institute, a library called the MpCCI, or Mesh-based Parallel Code Coupling Interface, has been implemented together with a library called STAMPI to couple two existing codes to develop an 'integrated numerical simulation system' intended for meta-computing environments. (authors)

  6. Problem solving teaching practices: Observer and teacher's view

    OpenAIRE

    Felmer , Patricio; Perdomo-Díaz , Josefa; Giaconi , Valentina; Espinoza , Carmen ,

    2015-01-01

    International audience; In this article, we report on an exploratory study on teaching practices related to problem solving of a group of 29 novel secondary mathematics teachers. For this purpose, two independent instruments were designed, the first one is based on lesson observations, and the second one is a questionnaire answered by teachers about their teaching practices while working on non-routine problem solving with their students. For each instrument, we perform a statistical analysis...

  7. Sensitivity of the solution of the Elder problem to density, velocity and numerical perturbations

    Science.gov (United States)

    Park, Chan-Hee; Aral, Mustafa M.

    2007-06-01

    In this paper the Elder problem is studied with the purpose of evaluating the inherent instabilities associated with the numerical solution of this problem. Our focus is first on the question of the existence of a unique numerical solution for this problem, and second on the grid density and fluid density requirements necessary for a unique numerical solution. In particular we have investigated the instability issues associated with the numerical solution of the Elder problem from the following perspectives: (i) physical instability issues associated with density differences; (ii) sensitivity of the numerical solution to idealization irregularities; and, (iii) the importance of a precise velocity field calculation and the association of this process with the grid density levels that is necessary to solve the Elder problem accurately. In the study discussed here we have used a finite element Galerkin model we have developed for solving density-dependent flow and transport problems, which will be identified as TechFlow. In our study, the numerical results of Frolkovič and de Schepper [Frolkovič, P. and H. de Schepper, 2001. Numerical modeling of convection dominated transport coupled with density-driven flow in porous media, Adv. Water Resour., 24, 63-72.] were replicated using the grid density employed in their work. We were also successful in duplicating the same result with a less dense grid but with more computational effort based on a global velocity estimation process we have adopted. Our results indicate that the global velocity estimation approach recommended by Yeh [Yeh, G.-T., 1981. On the computation of Darcian velocity and mass balance in finite element modelling of groundwater flow, Water Resour. Res., 17(5), 1529-1534.] allows the use of less dense grids while obtaining the same accuracy that can be achieved with denser grids. We have also observed that the regularity of the elements in the discretization of the solution domain does make a difference

  8. Numerical simulation of an elementary Vortex-Induced-Vibration problem by using fully-coupled fluid solid system computation

    Directory of Open Access Journals (Sweden)

    M Pomarède

    2016-09-01

    Full Text Available Numerical simulation of Vortex-Induced-Vibrations (VIV of a rigid circular elastically-mounted cylinder submitted to a fluid cross-flow has been extensively studied over the past decades, both experimentally and numerically, because of its theoretical and practical interest for understanding Flow-Induced-Vibrations (FIV problems. In this context, the present article aims to expose a numerical study based on fully-coupled fluid-solid computations compared to previously published work [34], [36]. The computational procedure relies on a partitioned method ensuring the coupling between fluid and structure solvers. The fluid solver involves a moving mesh formulation for simulation of the fluid structure interface motion. Energy exchanges between fluid and solid models are ensured through convenient numerical schemes. The present study is devoted to a low Reynolds number configuration. Cylinder motion magnitude, hydrodynamic forces, oscillation frequency and fluid vortex shedding modes are investigated and the “lock-in” phenomenon is reproduced numerically. These numerical results are proposed for code validation purposes before investigating larger industrial applications such as configurations involving tube arrays under cross-flows [4].

  9. NUMERICAL SIMULATION OF ELECTRICAL IMPEDANCE TOMOGRAPHY PROBLEM AND STUDY OF APPROACH BASED ON FINITE VOLUME METHOD

    Directory of Open Access Journals (Sweden)

    Ye. S. Sherina

    2014-01-01

    Full Text Available This research has been aimed to carry out a study of peculiarities that arise in a numerical simulation of the electrical impedance tomography (EIT problem. Static EIT image reconstruction is sensitive to a measurement noise and approximation error. A special consideration has been given to reducing of the approximation error, which originates from numerical implementation drawbacks. This paper presents in detail two numerical approaches for solving EIT forward problem. The finite volume method (FVM on unstructured triangular mesh is introduced. In order to compare this approach, the finite element (FEM based forward solver was implemented, which has gained the most popularity among researchers. The calculated potential distribution with the assumed initial conductivity distribution has been compared to the analytical solution of a test Neumann boundary problem and to the results of problem simulation by means of ANSYS FLUENT commercial software. Two approaches to linearized EIT image reconstruction are discussed. Reconstruction of the conductivity distribution is an ill-posed problem, typically requiring a large amount of computation and resolved by minimization techniques. The objective function to be minimized is constructed of measured voltage and calculated boundary voltage on the electrodes. A classical modified Newton type iterative method and the stochastic differential evolution method are employed. A software package has been developed for the problem under investigation. Numerical tests were conducted on simulated data. The obtained results could be helpful to researches tackling the hardware and software issues for medical applications of EIT.

  10. Cubic spline numerical solution of an ablation problem with convective backface cooling

    Science.gov (United States)

    Lin, S.; Wang, P.; Kahawita, R.

    1984-08-01

    An implicit numerical technique using cubic splines is presented for solving an ablation problem on a thin wall with convective cooling. A non-uniform computational mesh with 6 grid points has been used for the numerical integration. The method has been found to be computationally efficient, providing for the care under consideration of an overall error of about 1 percent. The results obtained indicate that the convective cooling is an important factor in reducing the ablation thickness.

  11. Numerical treatment of elliptic BVP with several solutions and of MHD equilibrium problems

    International Nuclear Information System (INIS)

    Meyer-Spasche, R.

    1975-12-01

    It is found out empirically that Newton iteration and difference methods are very suitable for the numerical treatment of elliptic boundary value problems (Lu)(x) = f(x,u(x)) in D c R 2 , u/deltaD = g having several solutions. Some convergence theorems for these methods are presented. Some notable numerical examples are given, including bifurcation diagrams, which are interesting in themselves and show also the applicability of the methods developed. (orig./WB) [de

  12. A numerical method for multigroup slab-geometry discrete ordinates problems with no spatial truncation error

    International Nuclear Information System (INIS)

    Barros, R.C. de; Larsen, E.W.

    1991-01-01

    A generalization of the one-group Spectral Green's Function (SGF) method is developed for multigroup, slab-geometry discrete ordinates (S N ) problems. The multigroup SGF method is free from spatial truncation errors; it generated numerical values for the cell-edge and cell-average angular fluxes that agree with the analytic solution of the multigroup S N equations. Numerical results are given to illustrate the method's accuracy

  13. The joint essential numerical range, compact perturbations, and the Olsen problem

    Czech Academy of Sciences Publication Activity Database

    Müller, Vladimír

    2010-01-01

    Roč. 197, č. 3 (2010), s. 275-290 ISSN 0039-3223 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional research plan: CEZ:AV0Z10190503 Keywords : joint essential numerical range * joint numerical range * compact perturbation * Olsen's problem Subject RIV: BA - General Mathematics Impact factor: 0.567, year: 2010 http://journals.impan.pl/cgi-bin/doi?sm197-3-5

  14. Finding practical solutions to complex problems: IDRC's fifth annual ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-04-15

    Apr 15, 2016 ... English · Français ... Finding practical solutions to complex problems: IDRC's fifth annual ... “IDRC staff share a common goal with the researchers they work with – to find low-cost, down-to-earth solutions to complex problems ...

  15. Arithmetic and algebraic problem solving and resource allocation: the distinct impact of fluid and numerical intelligence.

    Science.gov (United States)

    Dix, Annika; van der Meer, Elke

    2015-04-01

    This study investigates cognitive resource allocation dependent on fluid and numerical intelligence in arithmetic/algebraic tasks varying in difficulty. Sixty-six 11th grade students participated in a mathematical verification paradigm, while pupil dilation as a measure of resource allocation was collected. Students with high fluid intelligence solved the tasks faster and more accurately than those with average fluid intelligence, as did students with high compared to average numerical intelligence. However, fluid intelligence sped up response times only in students with average but not high numerical intelligence. Further, high fluid but not numerical intelligence led to greater task-related pupil dilation. We assume that fluid intelligence serves as a domain-general resource that helps to tackle problems for which domain-specific knowledge (numerical intelligence) is missing. The allocation of this resource can be measured by pupil dilation. Copyright © 2014 Society for Psychophysiological Research.

  16. A Numerical Approach to Solving an Inverse Heat Conduction Problem Using the Levenberg-Marquardt Algorithm

    Directory of Open Access Journals (Sweden)

    Tao Min

    2014-01-01

    Full Text Available This paper is intended to provide a numerical algorithm involving the combined use of the Levenberg-Marquardt algorithm and the Galerkin finite element method for estimating the diffusion coefficient in an inverse heat conduction problem (IHCP. In the present study, the functional form of the diffusion coefficient is unknown a priori. The unknown diffusion coefficient is approximated by the polynomial form and the present numerical algorithm is employed to find the solution. Numerical experiments are presented to show the efficiency of the proposed method.

  17. Sensitivity analysis of numerical results of one- and two-dimensional advection-diffusion problems

    International Nuclear Information System (INIS)

    Motoyama, Yasunori; Tanaka, Nobuatsu

    2005-01-01

    Numerical simulation has been playing an increasingly important role in the fields of science and engineering. However, every numerical result contains errors such as modeling, truncation, and computing errors, and the magnitude of the errors that are quantitatively contained in the results is unknown. This situation causes a large design margin in designing by analyses and prevents further cost reduction by optimizing design. To overcome this situation, we developed a new method to numerically analyze the quantitative error of a numerical solution by using the sensitivity analysis method and modified equation approach. If a reference case of typical parameters is calculated once by this method, then no additional calculation is required to estimate the results of other numerical parameters such as those of parameters with higher resolutions. Furthermore, we can predict the exact solution from the sensitivity analysis results and can quantitatively evaluate the error of numerical solutions. Since the method incorporates the features of the conventional sensitivity analysis method, it can evaluate the effect of the modeling error as well as the truncation error. In this study, we confirm the effectiveness of the method through some numerical benchmark problems of one- and two-dimensional advection-diffusion problems. (author)

  18. Numerical Solution of Time-Dependent Problems with a Fractional-Power Elliptic Operator

    Science.gov (United States)

    Vabishchevich, P. N.

    2018-03-01

    A time-dependent problem in a bounded domain for a fractional diffusion equation is considered. The first-order evolution equation involves a fractional-power second-order elliptic operator with Robin boundary conditions. A finite-element spatial approximation with an additive approximation of the operator of the problem is used. The time approximation is based on a vector scheme. The transition to a new time level is ensured by solving a sequence of standard elliptic boundary value problems. Numerical results obtained for a two-dimensional model problem are presented.

  19. Classical and modern numerical analysis theory, methods and practice

    CERN Document Server

    Ackleh, Azmy S; Kearfott, R Baker; Seshaiyer, Padmanabhan

    2009-01-01

    Mathematical Review and Computer Arithmetic Mathematical Review Computer Arithmetic Interval ComputationsNumerical Solution of Nonlinear Equations of One Variable Introduction Bisection Method The Fixed Point Method Newton's Method (Newton-Raphson Method) The Univariate Interval Newton MethodSecant Method and Müller's Method Aitken Acceleration and Steffensen's Method Roots of Polynomials Additional Notes and SummaryNumerical Linear Algebra Basic Results from Linear Algebra Normed Linear Spaces Direct Methods for Solving Linear SystemsIterative Methods for Solving Linear SystemsThe Singular Value DecompositionApproximation TheoryIntroduction Norms, Projections, Inner Product Spaces, and Orthogonalization in Function SpacesPolynomial ApproximationPiecewise Polynomial ApproximationTrigonometric ApproximationRational ApproximationWavelet BasesLeast Squares Approximation on a Finite Point SetEigenvalue-Eigenvector Computation Basic Results from Linear Algebra The Power Method The Inverse Power Method Deflation T...

  20. Numerical Study on Several Stabilized Finite Element Methods for the Steady Incompressible Flow Problem with Damping

    Directory of Open Access Journals (Sweden)

    Jilian Wu

    2013-01-01

    Full Text Available We discuss several stabilized finite element methods, which are penalty, regular, multiscale enrichment, and local Gauss integration method, for the steady incompressible flow problem with damping based on the lowest equal-order finite element space pair. Then we give the numerical comparisons between them in three numerical examples which show that the local Gauss integration method has good stability, efficiency, and accuracy properties and it is better than the others for the steady incompressible flow problem with damping on the whole. However, to our surprise, the regular method spends less CPU-time and has better accuracy properties by using Crout solver.

  1. Problem of the Moving Boundary in Continuous Casting Solved by The Analytic-Numerical Method

    Directory of Open Access Journals (Sweden)

    Grzymkowski R.

    2013-03-01

    Full Text Available Mathematical modeling of thermal processes combined with the reversible phase transitions of type: solid phase - liquid phase leads to formulation of the parabolic or elliptic moving boundary problem. Solution of such defined problem requires, most often, to use some sophisticated numerical techniques and far advanced mathematical tools. The paper presents an analytic-numerical method, especially attractive from the engineer’s point of view, applied for finding the approximate solutions of the selected class of problems which can be reduced to the one-phase solidification problem of a plate with the unknown a priori, varying in time boundary of the region in which the solution is sought. Proposed method is based on the known formalism of initial expansion of a sought function, describing the field of temperature, into the power series, some coefficients of which are determined with the aid of boundary conditions, and on the approximation of a function defining the freezing front location with the broken line, parameters of which are determined numerically. The method represents a combination of the analytical and numerical techniques and seems to be an effective and relatively easy in using tool for solving problems of considered kind.

  2. Problem of the Moving Boundary in Continuous Casting Solved by the Analytic-Numerical Method

    Directory of Open Access Journals (Sweden)

    R. Grzymkowski

    2013-01-01

    Full Text Available Mathematical modeling of thermal processes combined with the reversible phase transitions of type: solid phase – liquid phase leads to formulation of the parabolic or elliptic moving boundary problem. Solution of such defined problem requires, most often, to use some sophisticated numerical techniques and far advanced mathematical tools. The paper presents an analytic-numerical method, especially attractive from the engineer’s point of view, applied for finding the approximate solutions of the selected class of problems which can be reduced to the one-phase solidification problem of a plate with the unknown a priori, varying in time boundary of the region in which the solution is sought. Proposed method is based on the known formalism of initial expansion of a sought function, describing the field of temperature, into the power series, some coefficients of which are determined with the aid of boundary conditions, and on the approximation of a function defining the freezing front location with the broken line, parameters of which are determined numerically. The method represents a combination of the analytical and numerical techniques and seems to be an effective and relatively easy in using tool for solving problems of considered kind.

  3. Numerical methods for the design of large-scale nonlinear discrete ill-posed inverse problems

    International Nuclear Information System (INIS)

    Haber, E; Horesh, L; Tenorio, L

    2010-01-01

    Design of experiments for discrete ill-posed problems is a relatively new area of research. While there has been some limited work concerning the linear case, little has been done to study design criteria and numerical methods for ill-posed nonlinear problems. We present an algorithmic framework for nonlinear experimental design with an efficient numerical implementation. The data are modeled as indirect, noisy observations of the model collected via a set of plausible experiments. An inversion estimate based on these data is obtained by a weighted Tikhonov regularization whose weights control the contribution of the different experiments to the data misfit term. These weights are selected by minimization of an empirical estimate of the Bayes risk that is penalized to promote sparsity. This formulation entails a bilevel optimization problem that is solved using a simple descent method. We demonstrate the viability of our design with a problem in electromagnetic imaging based on direct current resistivity and magnetotelluric data

  4. A difference quotient-numerical integration method for solving radiative transfer problems

    International Nuclear Information System (INIS)

    Ding Peizhu

    1992-01-01

    A difference quotient-numerical integration method is adopted to solve radiative transfer problems in an anisotropic scattering slab medium. By using the method, the radiative transfer problem is separated into a system of linear algebraic equations and the coefficient matrix of the system is a band matrix, so the method is very simple to evaluate on computer and to deduce formulae and easy to master for experimentalists. An example is evaluated and it is shown that the method is precise

  5. Numerical Investigations on Several Stabilized Finite Element Methods for the Stokes Eigenvalue Problem

    Directory of Open Access Journals (Sweden)

    Pengzhan Huang

    2011-01-01

    Full Text Available Several stabilized finite element methods for the Stokes eigenvalue problem based on the lowest equal-order finite element pair are numerically investigated. They are penalty, regular, multiscale enrichment, and local Gauss integration method. Comparisons between them are carried out, which show that the local Gauss integration method has good stability, efficiency, and accuracy properties, and it is a favorite method among these methods for the Stokes eigenvalue problem.

  6. Numerical Methods for Solution of the Extended Linear Quadratic Control Problem

    DEFF Research Database (Denmark)

    Jørgensen, John Bagterp; Frison, Gianluca; Gade-Nielsen, Nicolai Fog

    2012-01-01

    In this paper we present the extended linear quadratic control problem, its efficient solution, and a discussion of how it arises in the numerical solution of nonlinear model predictive control problems. The extended linear quadratic control problem is the optimal control problem corresponding...... to the Karush-Kuhn-Tucker system that constitute the majority of computational work in constrained nonlinear and linear model predictive control problems solved by efficient MPC-tailored interior-point and active-set algorithms. We state various methods of solving the extended linear quadratic control problem...... and discuss instances in which it arises. The methods discussed in the paper have been implemented in efficient C code for both CPUs and GPUs for a number of test examples....

  7. A mathematical model and numerical solution of interface problems for steady state heat conduction

    Directory of Open Access Journals (Sweden)

    Z. Muradoglu Seyidmamedov

    2006-01-01

    (isolation Ωδ tends to zero. For each case, the local truncation errors of the used conservative finite difference scheme are estimated on the nonuniform grid. A fast direct solver has been applied for the interface problems with piecewise constant but discontinuous coefficient k=k(x. The presented numerical results illustrate high accuracy and show applicability of the given approach.

  8. Numerical method for solving the inverse problem of quantum scattering theory

    International Nuclear Information System (INIS)

    Ajrapetyan, R.G.; Puzynin, I.V.; Zhidkov, E.P.

    1996-01-01

    A new numerical method for solving the problem of the reconstruction of interaction potential by a phase shift given on a set of closed intervals in (l,k)-plane, satisfying certain geometrical 'Staircase Condition', is suggested. The method is based on the Variable Phase Approach and on the modification of the Continuous Analogy of the Newton Method. 22 refs., 1 fig

  9. Mathematical modelling and numerical resolution of multi-phase compressible fluid flows problems

    International Nuclear Information System (INIS)

    Lagoutiere, Frederic

    2000-01-01

    This work deals with Eulerian compressible multi-species fluid dynamics, the species being either mixed or separated (with interfaces). The document is composed of three parts. The first parts devoted to the numerical resolution of model problems: advection equation, Burgers equation, and Euler equations, in dimensions one and two. The goal is to find a precise method, especially for discontinuous initial conditions, and we develop non dissipative algorithms. They are based on a downwind finite-volume discretization under some stability constraints. The second part treats of the mathematical modelling of fluids mixtures. We construct and analyse a set of multi-temperature and multi-pressure models that are entropy, symmetrizable, hyperbolic, not ever conservative. In the third part, we apply the ideas developed in the first part (downwind discretization) to the numerical resolution of the partial differential problems we have constructed for fluids mixtures in the second part. We present some numerical results in dimensions one and two. (author) [fr

  10. The numerical analysis of eigenvalue problem solutions in the multigroup neutron diffusion theory

    International Nuclear Information System (INIS)

    Woznicki, Z.I.

    1994-01-01

    The main goal of this paper is to present a general iteration strategy for solving the discrete form of multidimensional neutron diffusion equations equivalent mathematically to an eigenvalue problem. Usually a solution method is based on different levels of iterations. The presented matrix formalism allows us to visualize explicitly how the used matrix splitting influences the matrix structure in an eigenvalue problem to be solved as well as the interdependence between inner and outer iteration within global iterations. Particular interactive strategies are illustrated by numerical results obtained for several reactor problems. (author). 21 refs, 32 figs, 15 tabs

  11. NUMERICAL ANALYSIS OF AN INVERSE PROBLEM ORIGINATED IN PHENOMENON OF POLLUTION AIR URBAN

    Directory of Open Access Journals (Sweden)

    Aníbal Coronel

    2016-12-01

    Full Text Available This paper presents the calibration study of a two - dimensional mathematical model for the problem of urban air pollution. It is mainly assumed that air pollution is afected by wind convection, diffusion and chemical reactions of pollutants. Consequently, a convection-diffusion-reaction equation is obtained as a direct problem. In the inverse problem, the determination of the diffusion is analyzed, assuming that one has an observation of the pollutants in a nite time. To solve it numerically the nite volume method is used, the least squares function is considered as cost function and the gradient is calculated with the sensitivity method.

  12. The numerical analysis of eigenvalue problem solutions in the multigroup neutron diffusion theory

    Energy Technology Data Exchange (ETDEWEB)

    Woznicki, Z I [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1994-12-31

    The main goal of this paper is to present a general iteration strategy for solving the discrete form of multidimensional neutron diffusion equations equivalent mathematically to an eigenvalue problem. Usually a solution method is based on different levels of iterations. The presented matrix formalism allows us to visualize explicitly how the used matrix splitting influences the matrix structure in an eigenvalue problem to be solved as well as the interdependence between inner and outer iteration within global iterations. Particular interactive strategies are illustrated by numerical results obtained for several reactor problems. (author). 21 refs, 32 figs, 15 tabs.

  13. The numerical analysis of eigenvalue problem solutions in multigroup neutron diffusion theory

    International Nuclear Information System (INIS)

    Woznicki, Z.I.

    1995-01-01

    The main goal of this paper is to present a general iteration strategy for solving the discrete form of multidimensional neutron diffusion equations equivalent mathematically to an eigenvalue problem. Usually a solution method is based on different levels of iterations. The presented matrix formalism allows us to visualize explicitly how the used matrix splitting influences the matrix structure in an eigenvalue problem to be solved as well as the interdependence between inner and outer iterations within global iterations. Particular iterative strategies are illustrated by numerical results obtained for several reactor problems. (author). 21 refs, 35 figs, 16 tabs

  14. Two numerical methods for an inverse problem for the 2-D Helmholtz equation

    CERN Document Server

    Gryazin, Y A; Lucas, T R

    2003-01-01

    Two solution methods for the inverse problem for the 2-D Helmholtz equation are developed, tested, and compared. The proposed approaches are based on a marching finite-difference scheme which requires the solution of an overdetermined system at each step. The preconditioned conjugate gradient method is used for rapid solutions of these systems and an efficient preconditioner has been developed for this class of problems. Underlying target applications include the imaging of land mines, unexploded ordinance, and pollutant plumes in environmental cleanup sites, each formulated as an inverse problem for a 2-D Helmholtz equation. The images represent the electromagnetic properties of the respective underground regions. Extensive numerical results are presented.

  15. On the formulation and numerical simulation of distributed-order fractional optimal control problems

    Science.gov (United States)

    Zaky, M. A.; Machado, J. A. Tenreiro

    2017-11-01

    In a fractional optimal control problem, the integer order derivative is replaced by a fractional order derivative. The fractional derivative embeds implicitly the time delays in an optimal control process. The order of the fractional derivative can be distributed over the unit interval, to capture delays of distinct sources. The purpose of this paper is twofold. Firstly, we derive the generalized necessary conditions for optimal control problems with dynamics described by ordinary distributed-order fractional differential equations (DFDEs). Secondly, we propose an efficient numerical scheme for solving an unconstrained convex distributed optimal control problem governed by the DFDE. We convert the problem under consideration into an optimal control problem governed by a system of DFDEs, using the pseudo-spectral method and the Jacobi-Gauss-Lobatto (J-G-L) integration formula. Next, we present the numerical solutions for a class of optimal control problems of systems governed by DFDEs. The convergence of the proposed method is graphically analyzed showing that the proposed scheme is a good tool for the simulation of distributed control problems governed by DFDEs.

  16. Efficient numerical methods for the large-scale, parallel solution of elastoplastic contact problems

    KAUST Repository

    Frohne, Jörg

    2015-08-06

    © 2016 John Wiley & Sons, Ltd. Quasi-static elastoplastic contact problems are ubiquitous in many industrial processes and other contexts, and their numerical simulation is consequently of great interest in accurately describing and optimizing production processes. The key component in these simulations is the solution of a single load step of a time iteration. From a mathematical perspective, the problems to be solved in each time step are characterized by the difficulties of variational inequalities for both the plastic behavior and the contact problem. Computationally, they also often lead to very large problems. In this paper, we present and evaluate a complete set of methods that are (1) designed to work well together and (2) allow for the efficient solution of such problems. In particular, we use adaptive finite element meshes with linear and quadratic elements, a Newton linearization of the plasticity, active set methods for the contact problem, and multigrid-preconditioned linear solvers. Through a sequence of numerical experiments, we show the performance of these methods. This includes highly accurate solutions of a three-dimensional benchmark problem and scaling our methods in parallel to 1024 cores and more than a billion unknowns.

  17. Efficient numerical methods for the large-scale, parallel solution of elastoplastic contact problems

    KAUST Repository

    Frohne, Jö rg; Heister, Timo; Bangerth, Wolfgang

    2015-01-01

    © 2016 John Wiley & Sons, Ltd. Quasi-static elastoplastic contact problems are ubiquitous in many industrial processes and other contexts, and their numerical simulation is consequently of great interest in accurately describing and optimizing production processes. The key component in these simulations is the solution of a single load step of a time iteration. From a mathematical perspective, the problems to be solved in each time step are characterized by the difficulties of variational inequalities for both the plastic behavior and the contact problem. Computationally, they also often lead to very large problems. In this paper, we present and evaluate a complete set of methods that are (1) designed to work well together and (2) allow for the efficient solution of such problems. In particular, we use adaptive finite element meshes with linear and quadratic elements, a Newton linearization of the plasticity, active set methods for the contact problem, and multigrid-preconditioned linear solvers. Through a sequence of numerical experiments, we show the performance of these methods. This includes highly accurate solutions of a three-dimensional benchmark problem and scaling our methods in parallel to 1024 cores and more than a billion unknowns.

  18. The effects of cumulative practice on mathematics problem solving.

    Science.gov (United States)

    Mayfield, Kristin H; Chase, Philip N

    2002-01-01

    This study compared three different methods of teaching five basic algebra rules to college students. All methods used the same procedures to teach the rules and included four 50-question review sessions interspersed among the training of the individual rules. The differences among methods involved the kinds of practice provided during the four review sessions. Participants who received cumulative practice answered 50 questions covering a mix of the rules learned prior to each review session. Participants who received a simple review answered 50 questions on one previously trained rule. Participants who received extra practice answered 50 extra questions on the rule they had just learned. Tests administered after each review included new questions for applying each rule (application items) and problems that required novel combinations of the rules (problem-solving items). On the final test, the cumulative group outscored the other groups on application and problem-solving items. In addition, the cumulative group solved the problem-solving items significantly faster than the other groups. These results suggest that cumulative practice of component skills is an effective method of training problem solving.

  19. On the Validation of a Numerical Model for the Analysis of Soil-Structure Interaction Problems

    Directory of Open Access Journals (Sweden)

    Jorge Luis Palomino Tamayo

    Full Text Available Abstract Modeling and simulation of mechanical response of structures, relies on the use of computational models. Therefore, verification and validation procedures are the primary means of assessing accuracy, confidence and credibility in modeling. This paper is concerned with the validation of a three dimensional numerical model based on the finite element method suitable for the dynamic analysis of soil-structure interaction problems. The soil mass, structure, structure's foundation and the appropriate boundary conditions can be represented altogether in a single model by using a direct approach. The theory of porous media of Biot is used to represent the soil mass as a two-phase material which is considered to be fully saturated with water; meanwhile other parts of the system are treated as one-phase materials. Plasticity of the soil mass is the main source of non-linearity in the problem and therefore an iterative-incremental algorithm based on the Newton-Raphson procedure is used to solve the nonlinear equilibrium equations. For discretization in time, the Generalized Newmark-β method is used. The soil is represented by a plasticity-based, effective-stress constitutive model suitable for liquefaction. Validation of the present numerical model is done by comparing analytical and centrifuge test results of soil and soil-pile systems with those results obtained with the present numerical model. A soil-pile-structure interaction problem is also presented in order to shown the potentiality of the numerical tool.

  20. Reduced Numerical Approximation of Reduced Fluid-Structure Interaction Problems With Applications in Hemodynamics

    Directory of Open Access Journals (Sweden)

    Claudia M. Colciago

    2018-06-01

    Full Text Available This paper deals with fast simulations of the hemodynamics in large arteries by considering a reduced model of the associated fluid-structure interaction problem, which in turn allows an additional reduction in terms of the numerical discretisation. The resulting method is both accurate and computationally cheap. This goal is achieved by means of two levels of reduction: first, we describe the model equations with a reduced mathematical formulation which allows to write the fluid-structure interaction problem as a Navier-Stokes system with non-standard boundary conditions; second, we employ numerical reduction techniques to further and drastically lower the computational costs. The non standard boundary condition is of a generalized Robin type, with a boundary mass and boundary stiffness terms accounting for the arterial wall compliance. The numerical reduction is obtained coupling two well-known techniques: the proper orthogonal decomposition and the reduced basis method, in particular the greedy algorithm. We start by reducing the numerical dimension of the problem at hand with a proper orthogonal decomposition and we measure the system energy with specific norms; this allows to take into account the different orders of magnitude of the state variables, the velocity and the pressure. Then, we introduce a strategy based on a greedy procedure which aims at enriching the reduced discretization space with low offline computational costs. As application, we consider a realistic hemodynamics problem with a perturbation in the boundary conditions and we show the good performances of the reduction techniques presented in the paper. The results obtained with the numerical reduction algorithm are compared with the one obtained by a standard finite element method. The gains obtained in term of CPU time are of three orders of magnitude.

  1. A numerical technique for solving fractional optimal control problems and fractional Riccati differential equations

    Directory of Open Access Journals (Sweden)

    F. Ghomanjani

    2016-10-01

    Full Text Available In the present paper, we apply the Bezier curves method for solving fractional optimal control problems (OCPs and fractional Riccati differential equations. The main advantage of this method is that it can reduce the error of the approximate solutions. Hence, the solutions obtained using the Bezier curve method give good approximations. Some numerical examples are provided to confirm the accuracy of the proposed method. All of the numerical computations have been performed on a PC using several programs written in MAPLE 13.

  2. Managing problem employees: a model program and practical guide.

    Science.gov (United States)

    Miller, Laurence

    2010-01-01

    This article presents a model program for managing problem employees that includes a description ofthe basic types of problem employees and employee problems, as well as practical recommendations for. (1) selection and screening, (2) education and training, (3) coaching and counseling, (4) discipline, (5) psychological fitness-for-duty evaluations, (6) mental health services, (7) termination, and (8) leadership and administrative strategies. Throughout, the emphasis on balancing the need for order and productivity in the workplace with fairness and concern for employee health and well-being.

  3. The Current Practices and Problems of School Based Supervision in ...

    African Journals Online (AJOL)

    The purpose of this study was to identify the current practice and problems of school based supervision in government primary schools of Jile Timuga Woreda of Oromia Zone. A descriptive survey design of research methodology was employed. Regarding sampling, there were 39 primary schools grouped in 10 cluster ...

  4. The problem of egoism in Rousseau’s practical philosophy

    Directory of Open Access Journals (Sweden)

    Sadžakov Slobodan

    2012-01-01

    Full Text Available This paper discusses the aspects of Rousseau’s understandimg of egoism, primarily those related to his highlighting of historical dimension of the problem, including the economical reasons for establishing this practical principle as an important part of the civil reproduction of life. Among other things, it analyses the contextual connection of egoism with relevant definitions in Rousseau’s work such as human nature, natural law, general will etc. and the difference of Rousseau’s overview of this problem from other important philosophers, for example Hobbes. This paper underlines how the French philosopher, on the basis of key assumptions of his practical philosophy, points at the historical dependence and the possibility of overcoming the egoistic actions, and endeavors to pave the way to a multilateral practical unlocking of the potentials of freedom in its political, moral and legal sense.

  5. Numerical method in reproducing kernel space for an inverse source problem for the fractional diffusion equation

    International Nuclear Information System (INIS)

    Wang, Wenyan; Han, Bo; Yamamoto, Masahiro

    2013-01-01

    We propose a new numerical method for reproducing kernel Hilbert space to solve an inverse source problem for a two-dimensional fractional diffusion equation, where we are required to determine an x-dependent function in a source term by data at the final time. The exact solution is represented in the form of a series and the approximation solution is obtained by truncating the series. Furthermore, a technique is proposed to improve some of the existing methods. We prove that the numerical method is convergent under an a priori assumption of the regularity of solutions. The method is simple to implement. Our numerical result shows that our method is effective and that it is robust against noise in L 2 -space in reconstructing a source function. (paper)

  6. Numerical continuation methods for dynamical systems path following and boundary value problems

    CERN Document Server

    Krauskopf, Bernd; Galan-Vioque, Jorge

    2007-01-01

    Path following in combination with boundary value problem solvers has emerged as a continuing and strong influence in the development of dynamical systems theory and its application. It is widely acknowledged that the software package AUTO - developed by Eusebius J. Doedel about thirty years ago and further expanded and developed ever since - plays a central role in the brief history of numerical continuation. This book has been compiled on the occasion of Sebius Doedel''s 60th birthday. Bringing together for the first time a large amount of material in a single, accessible source, it is hoped that the book will become the natural entry point for researchers in diverse disciplines who wish to learn what numerical continuation techniques can achieve. The book opens with a foreword by Herbert B. Keller and lecture notes by Sebius Doedel himself that introduce the basic concepts of numerical bifurcation analysis. The other chapters by leading experts discuss continuation for various types of systems and objects ...

  7. Numerical solution of electromagnetic field problems in two and three dimensions

    International Nuclear Information System (INIS)

    Trowbridge, C.W.

    1981-01-01

    Recent developments in algorithms for solving electromagnetic field problems carried out at Rutherford Appleton Laboratory (RAL) are reviewed. The interaction of electric and magnetic fields provides many examples of coupled problems which have been solved by the Finite Element method. This paper concentrates on static and low frequency problems using the differential operator approach. The status of computation for 2D fields is discussed. The use of scalar potentials for 3D static fields for economy is emphasised and the importance of selecting potential types carefully to minimise numerical cancellation errors is also discussed. Some formulations for the vector 3D field problem for eddy current fields are derived with analytic and experimental field measurement comparisons. Results using software packages built at RAL are presented to illustrate the methods. (author)

  8. Vectorization on the star computer of several numerical methods for a fluid flow problem

    Science.gov (United States)

    Lambiotte, J. J., Jr.; Howser, L. M.

    1974-01-01

    A reexamination of some numerical methods is considered in light of the new class of computers which use vector streaming to achieve high computation rates. A study has been made of the effect on the relative efficiency of several numerical methods applied to a particular fluid flow problem when they are implemented on a vector computer. The method of Brailovskaya, the alternating direction implicit method, a fully implicit method, and a new method called partial implicitization have been applied to the problem of determining the steady state solution of the two-dimensional flow of a viscous imcompressible fluid in a square cavity driven by a sliding wall. Results are obtained for three mesh sizes and a comparison is made of the methods for serial computation.

  9. A Numerical method for solving a class of fractional Sturm-Liouville eigenvalue problems

    Directory of Open Access Journals (Sweden)

    Muhammed I. Syam

    2017-11-01

    Full Text Available This article is devoted to both theoretical and numerical studies of eigenvalues of regular fractional $2\\alpha $-order Sturm-Liouville problem where $\\frac{1}{2}< \\alpha \\leq 1$. In this paper, we implement the reproducing kernel method RKM to approximate the eigenvalues. To find the eigenvalues, we force the approximate solution produced by the RKM satisfy the boundary condition at $x=1$. The fractional derivative is described in the Caputo sense. Numerical results demonstrate the accuracy of the present algorithm. In addition, we prove the existence of the eigenfunctions of the proposed problem. Uniformly convergence of the approximate eigenfunctions produced by the RKM to the exact eigenfunctions is proven.

  10. A Comparative Study of Differential Evolution, Particle Swarm Optimization, and Evolutionary Algorithms on Numerical Benchmark Problems

    DEFF Research Database (Denmark)

    Vesterstrøm, Jacob Svaneborg; Thomsen, Rene

    2004-01-01

    Several extensions to evolutionary algorithms (EAs) and particle swarm optimization (PSO) have been suggested during the last decades offering improved performance on selected benchmark problems. Recently, another search heuristic termed differential evolution (DE) has shown superior performance...... in several real-world applications. In this paper, we evaluate the performance of DE, PSO, and EAs regarding their general applicability as numerical optimization techniques. The comparison is performed on a suite of 34 widely used benchmark problems. The results from our study show that DE generally...... outperforms the other algorithms. However, on two noisy functions, both DE and PSO were outperformed by the EA....

  11. Enriched Meshfree Method for an Accurate Numerical Solution of the Motz Problem

    Directory of Open Access Journals (Sweden)

    Won-Tak Hong

    2016-01-01

    Full Text Available We present an enriched meshfree solution of the Motz problem. The Motz problem has been known as a benchmark problem to verify the efficiency of numerical methods in the presence of a jump boundary data singularity at a point, where an abrupt change occurs for the boundary condition. We propose a singular basis function enrichment technique in the context of partition of unity based meshfree method. We take the leading terms of the local series expansion at the point singularity and use them as enrichment functions for the local approximation space. As a result, we obtain highly accurate leading coefficients of the Motz problem that are comparable to the most accurate numerical solution. The proposed singular enrichment technique is highly effective in the case of the local series expansion of the solution being known. The enrichment technique that is used in this study can be applied to monotone singularities (of type rα with α<1 as well as oscillating singularities (of type rαsin⁡(ϵlog⁡r. It is the first attempt to apply singular meshfree enrichment technique to the Motz problem.

  12. Numerical sensitivity computation for discontinuous gradient-only optimization problems using the complex-step method

    CSIR Research Space (South Africa)

    Wilke, DN

    2012-07-01

    Full Text Available problems that utilise remeshing (i.e. the mesh topology is allowed to change) between design updates. Here, changes in mesh topology result in abrupt changes in the discretization error of the computed response. These abrupt changes in turn manifests... in shape optimization but may be present whenever (partial) differential equations are ap- proximated numerically with non-constant discretization methods e.g. remeshing of spatial domains or automatic time stepping in temporal domains. Keywords: Complex...

  13. Mathematical and numerical analysis of PN models for photons transport problems

    International Nuclear Information System (INIS)

    Valentin, Xavier

    2015-01-01

    Computational costs for direct numerical simulations of photon transport problems are very high in terms of CPU time and memory. One way to tackle this issue is to develop reduced models that a cheaper to solve numerically. There exists number of these models: moments models, discrete ordinates models (S N ), diffusion-like models... In this thesis, we focus on P N models in which the transport operator is approached by mean of a truncated development on the spherical harmonics basis. These models are arbitrary accurate in the angular dimension and are rotationally invariants (in multiple space dimensions). The latter point is fundamental when one wants to simulate inertial confinement fusion (ICF) experiments where the spherical symmetry plays an important part in the accuracy of the numerical solutions. We study the mathematical structure of the PN models and construct a new numerical method in the special case of a one dimensional space dimension with spherical symmetry photon transport problems. We first focus on a linear transport problem in the vacuum. Even in this simple case, it appears in the P N equations geometrical source terms that are stiff in the neighborhood of r = 0 and thus hard to discretize. Existing numerical methods are not satisfactory for multiple reasons: (1) inaccuracy in the neighborhood of r = 0 ('flux-dip'), (2) do not capture steady states (well-balanced scheme), (3) no stability proof. Following recent works, we develop a new well-balanced scheme for which we show the L 2 stability. We then extend the scheme for photon transport problems within a no moving media, the linear Boltzmann equation, and interest ourselves on its behavior in the diffusion limit (asymptotic-preserving property). In a second part, we consider radiation hydrodynamics problems. Since modelization of these problems is still under discussion in the literature, we compare a set of existing models by mean of mathematical analysis and establish a hierarchy

  14. Numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities

    International Nuclear Information System (INIS)

    Milioli, F.E.

    1985-01-01

    In this research work a numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities of a Boussinesq fluid is presented. The conservation equations are written in a general curvilinear coordinate system which matches the irregular boundaries of the domain. The nonorthogonal system is generated by a suitable system of elliptic equations. The momentum and continuity equations are transformed from the Cartesian system to the general curvilinear system keeping the Cartesian velocity components as the dependent variables in the transformed domain. Finite difference equations are obtained for the contravariant velocity components in the transformed domain. The numerical calculations are performed in a fixed rectangular domain and both the Cartesian and the contravariant velocity components take part in the solutiomn procedure. The dependent variables are arranged on the grid in a staggered manner. The numerical model is tested by solving the driven flow in a square cavity with a moving side using a nonorthogoanl grid. The natural convenction in a square cavity, using an orthogonal and a nonorthogonal grid, is also solved for the model test. Also, the solution for the buoyancy flow between a square cylinder placed inside a circular cylinder is presented. The results of the test problems are compared with those available in the specialized literature. Finally, in order to show the generality of the model, the natural convection problem inside a very irregular cavity is presented. (Author) [pt

  15. Off-Label Drug Use in Pediatric Practice: Unsolved Problems

    Directory of Open Access Journals (Sweden)

    A. R. Titova

    2015-01-01

    Full Text Available The widespread «off-label» drug use and the prescribing of unlicensed medicines in pediatric practice is a major health problem. The authors discuss actual regulatory and legal issues of «off-label» drug use in children in the US, Europe and Russia. The results of different population-based studies from many countries, showing the structure and frequency of «off-label» drug use in children, are summarized in this article. It is shown that such practice increases the risk of adverse drug reactions. The authors offer practical recommendations for a safer use of drugs in pediatric practice. The priority issue is conducting high quality clinical trials with the participation of children, improving national pharmacovigilance and the monitoring of off-label drug use, developing pediatric formularies, improving doctors’ knowledge and awareness of safety and efficacy of medicines in pediatric population.

  16. Comptonization in Ultra-Strong Magnetic Fields: Numerical Solution to the Radiative Transfer Problem

    Science.gov (United States)

    Ceccobello, C.; Farinelli, R.; Titarchuk, L.

    2014-01-01

    We consider the radiative transfer problem in a plane-parallel slab of thermal electrons in the presence of an ultra-strong magnetic field (B approximately greater than B(sub c) approx. = 4.4 x 10(exp 13) G). Under these conditions, the magnetic field behaves like a birefringent medium for the propagating photons, and the electromagnetic radiation is split into two polarization modes, ordinary and extraordinary, that have different cross-sections. When the optical depth of the slab is large, the ordinary-mode photons are strongly Comptonized and the photon field is dominated by an isotropic component. Aims. The radiative transfer problem in strong magnetic fields presents many mathematical issues and analytical or numerical solutions can be obtained only under some given approximations. We investigate this problem both from the analytical and numerical point of view, provide a test of the previous analytical estimates, and extend these results with numerical techniques. Methods. We consider here the case of low temperature black-body photons propagating in a sub-relativistic temperature plasma, which allows us to deal with a semi-Fokker-Planck approximation of the radiative transfer equation. The problem can then be treated with the variable separation method, and we use a numerical technique to find solutions to the eigenvalue problem in the case of a singular kernel of the space operator. The singularity of the space kernel is the result of the strong angular dependence of the electron cross-section in the presence of a strong magnetic field. Results. We provide the numerical solution obtained for eigenvalues and eigenfunctions of the space operator, and the emerging Comptonization spectrum of the ordinary-mode photons for any eigenvalue of the space equation and for energies significantly lesser than the cyclotron energy, which is on the order of MeV for the intensity of the magnetic field here considered. Conclusions. We derived the specific intensity of the

  17. Finite-State Mean-Field Games, Crowd Motion Problems, and its Numerical Methods

    KAUST Repository

    Machado Velho, Roberto

    2017-09-10

    In this dissertation, we present two research projects, namely finite-state mean-field games and the Hughes model for the motion of crowds. In the first part, we describe finite-state mean-field games and some applications to socio-economic sciences. Examples include paradigm shifts in the scientific community and the consumer choice behavior in a free market. The corresponding finite-state mean-field game models are hyperbolic systems of partial differential equations, for which we propose and validate a new numerical method. Next, we consider the dual formulation to two-state mean-field games, and we discuss numerical methods for these problems. We then depict different computational experiments, exhibiting a variety of behaviors, including shock formation, lack of invertibility, and monotonicity loss. We conclude the first part of this dissertation with an investigation of the shock structure for two-state problems. In the second part, we consider a model for the movement of crowds proposed by R. Hughes in [56] and describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an Eikonal equation with Dirichlet or Neumann data. We first establish a priori estimates for the solutions. Next, we consider radial solutions, and we identify a shock formation mechanism. Subsequently, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. We also propose a new numerical method for the solution of Fokker-Planck equations and then to systems of PDEs composed by a Fokker-Planck equation and a potential type equation. Finally, we illustrate the use of the numerical method both to the Hughes model and mean-field games. We also depict cases such as the evacuation of a room and the movement of persons around Kaaba (Saudi Arabia).

  18. The Role of Problem Solving in Construction Management Practices

    DEFF Research Database (Denmark)

    Schultz, Casper Siebken

    2012-01-01

    industry. An Industrial PhD carried out at a large Danish contractor examined how failures and defects are produced and handled in the social practices of construction projects. The study addresses quality issues related to project management and examines the role of problem solving practices......Quality issues are a topic of continuous interest in the Danish construction industry. Not only can failures and defects be vital to the success of the single project but also the annual profits of the whole company can be put at risk. Moreover quality issues jeopardize the reputation of the entire......-dispositions regarding quality issues in the decision making and redressing of defects and failures in the processes. The role of problem solving and trouble-shooting is analysed through the well-organized processes of erecting the precast concrete structure and the chaotic processes of constructing the penthouse storey...

  19. Externalizing and internalizing problems: contributions of attachment and parental practices

    Directory of Open Access Journals (Sweden)

    Sandra Adriana Neves Nunes

    2013-01-01

    Full Text Available The relation between attachment and parental practices with externalizing (aggression and delinquency and internalizing (social withdrawal and anxiety/depression behavioral problems were investigated in this study. Participants were 289 children (from 9 to 12 years old and 205 caregivers who answered distinct questionnaires: the formers on attachment and the later on parental practices. Results indicated that poor maternal attachment relationships, high levels of parental rejection and being a boy predicted aggression. Moreover, poor paternal attachment and father's low education predicted social withdrawal. Finally, parental rejection was marginally associated with anxiety/depression. The results reinforce, partially, the existing literature and help to understand the complex relationship between parenting and behavioral problems.

  20. Numerical solution of large nonlinear boundary value problems by quadratic minimization techniques

    International Nuclear Information System (INIS)

    Glowinski, R.; Le Tallec, P.

    1984-01-01

    The objective of this paper is to describe the numerical treatment of large highly nonlinear two or three dimensional boundary value problems by quadratic minimization techniques. In all the different situations where these techniques were applied, the methodology remains the same and is organized as follows: 1) derive a variational formulation of the original boundary value problem, and approximate it by Galerkin methods; 2) transform this variational formulation into a quadratic minimization problem (least squares methods) or into a sequence of quadratic minimization problems (augmented lagrangian decomposition); 3) solve each quadratic minimization problem by a conjugate gradient method with preconditioning, the preconditioning matrix being sparse, positive definite, and fixed once for all in the iterative process. This paper will illustrate the methodology above on two different examples: the description of least squares solution methods and their application to the solution of the unsteady Navier-Stokes equations for incompressible viscous fluids; the description of augmented lagrangian decomposition techniques and their application to the solution of equilibrium problems in finite elasticity

  1. A numerical method for interaction problems between fluid and membranes with arbitrary permeability for fluid

    Science.gov (United States)

    Miyauchi, Suguru; Takeuchi, Shintaro; Kajishima, Takeo

    2017-09-01

    We develop a numerical method for fluid-membrane interaction accounting for permeation of the fluid using a non-conforming mesh to the membrane shape. To represent the permeation flux correctly, the proposed finite element discretization incorporates the discontinuities in the velocity gradient and pressure on the membrane surface with specially selected base functions. The discontinuities are represented with independent variables and determined to satisfy the governing equations including the interfacial condition on the permeation. The motions of the fluid, membrane and permeation flux are coupled monolithically and time-advanced fully-implicitly. The validity and effectiveness of the proposed method are demonstrated by several two-dimensional fluid-membrane interaction problems of Stokes flows by comparing with the analytical models and numerical results obtained by other methods. The reproduced sharp discontinuities are found to be essential to suppress the non-physical permeation flux. Further, combined with the numerical treatment for the solute concentration across the membrane, the proposed method is applied to a fluid-structure interaction problem including the osmotic pressure difference.

  2. The Influence of Parenting Practices on Feeding Problems in Preschoolers

    Directory of Open Access Journals (Sweden)

    Nuria de la Osa

    2015-12-01

    Full Text Available The aim of the study is to estimate the prevalence of feeding problems during the preschool period and to explore the associations of feeding related behaviors with parenting practices. Participants were a large community sample of N = 622 children longitudinally assessed yearly at ages 3, 4 and 5 years-old through diagnostic interview and questionnaires reported by parents. The prevalence of children who met DSM-IV criteria for feeding disorder during the follow-up was 1.6%, the amount of children who presented feeding disorder symptoms was 33.3%, those with clinical impairment due to these symptoms were 25.7% and 11.6% reported seek for professional help related to feeding problems. Logistic regressions adjusted to children's sex and other DSM-IV diagnoses different to feeding disorder showed that the dimensions of parenting more strongly related to feeding related behaviors and impairment due to feeding problems were poor monitoring, inconsistence practices, corporal punishment, low norms and low autonomy. Although the prevalence of preschool children who met DSM-IV criteria for feeding disorder was relatively low, the presence of feeding related behaviors (symptoms, impairment and consultation was common during this developmental period. Parenting practices are associated to the presence of these behaviors, and so they must be considered into the prevention and intervention programs.

  3. Problem-Oriented Simulation Packages and Computational Infrastructure for Numerical Studies of Powerful Gyrotrons

    International Nuclear Information System (INIS)

    Damyanova, M; Sabchevski, S; Vasileva, E; Balabanova, E; Zhelyazkov, I; Dankov, P; Malinov, P

    2016-01-01

    Powerful gyrotrons are necessary as sources of strong microwaves for electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) of magnetically confined plasmas in various reactors (most notably ITER) for controlled thermonuclear fusion. Adequate physical models and efficient problem-oriented software packages are essential tools for numerical studies, analysis, optimization and computer-aided design (CAD) of such high-performance gyrotrons operating in a CW mode and delivering output power of the order of 1-2 MW. In this report we present the current status of our simulation tools (physical models, numerical codes, pre- and post-processing programs, etc.) as well as the computational infrastructure on which they are being developed, maintained and executed. (paper)

  4. Criteria for the reliability of numerical approximations to the solution of fluid flow problems

    International Nuclear Information System (INIS)

    Foias, C.

    1986-01-01

    The numerical approximation of the solutions of fluid flows models is a difficult problem in many cases of energy research. In all numerical methods implementable on digital computers, a basic question is if the number N of elements (Galerkin modes, finite-difference cells, finite-elements, etc.) is sufficient to describe the long time behavior of the exact solutions. It was shown using several approaches that some of the estimates based on physical intuition of N are rigorously valid under very general conditions and follow directly from the mathematical theory of the Navier-Stokes equations. Among the mathematical approaches to these estimates, the most promising (which can be and was already applied to many other dissipative partial differential systems) consists in giving upper estimates to the fractal dimension of the attractor associated to one (or all) solution(s) of the respective partial differential equations. 56 refs

  5. A combined analytic-numeric approach for some boundary-value problems

    Directory of Open Access Journals (Sweden)

    Mustafa Turkyilmazoglu

    2016-02-01

    Full Text Available A combined analytic-numeric approach is undertaken in the present work for the solution of boundary-value problems in the finite or semi-infinite domains. Equations to be treated arise specifically from the boundary layer analysis of some two and three-dimensional flows in fluid mechanics. The purpose is to find quick but accurate enough solutions. Taylor expansions at either boundary conditions are computed which are next matched to the other asymptotic or exact boundary conditions. The technique is applied to the well-known Blasius as well as Karman flows. Solutions obtained in terms of series compare favorably with the existing ones in the literature.

  6. Application of a numerical Laplace transform inversion technique to a problem in reactor dynamics

    International Nuclear Information System (INIS)

    Ganapol, B.D.; Sumini, M.

    1990-01-01

    A newly developed numerical technique for the Laplace transform inversion is applied to a classical time-dependent problem of reactor physics. The dynamic behaviour of a multiplying system has been analyzed through a continuous slowing down model, taking into account a finite slowing down time, the presence of several groups of neutron precursors and simplifying the spatial analysis using the space asymptotic approximation. The results presented, show complete agreement with analytical ones previously obtained and allow a deeper understanding of the model features. (author)

  7. Numerical nonlinear complex geometrical optics algorithm for the 3D Calderón problem

    DEFF Research Database (Denmark)

    Delbary, Fabrice; Knudsen, Kim

    2014-01-01

    to the generalized Laplace equation. The 3D problem was solved in theory in late 1980s using complex geometrical optics solutions and a scattering transform. Several approximations to the reconstruction method have been suggested and implemented numerically in the literature, but here, for the first time, a complete...... computer implementation of the full nonlinear algorithm is given. First a boundary integral equation is solved by a Nystrom method for the traces of the complex geometrical optics solutions, second the scattering transform is computed and inverted using fast Fourier transform, and finally a boundary value...

  8. A numerical method for finding sign-changing solutions of superlinear Dirichlet problems

    Energy Technology Data Exchange (ETDEWEB)

    Neuberger, J.M.

    1996-12-31

    In a recent result it was shown via a variational argument that a class of superlinear elliptic boundary value problems has at least three nontrivial solutions, a pair of one sign and one which sign changes exactly once. These three and all other nontrivial solutions are saddle points of an action functional, and are characterized as local minima of that functional restricted to a codimension one submanifold of the Hilbert space H-0-1-2, or an appropriate higher codimension subset of that manifold. In this paper, we present a numerical Sobolev steepest descent algorithm for finding these three solutions.

  9. Numerical modeling of time domain 3-D problems in accelerator physics

    International Nuclear Information System (INIS)

    Harfoush, F.A.; Jurgens, T.G.

    1990-06-01

    Time domain analysis is relevant in particle accelerators to study the electromagnetic field interaction of a moving source particle on a lagging test particle as the particles pass an accelerating cavity or some other structure. These fields are called wake fields. The travelling beam inside a beam pipe may undergo more complicated interactions with its environment due to the presence of other irregularities like wires, thin slots, joints and other types of obstacles. Analytical solutions of such problems is impossible and one has to resort to a numerical method. In this paper we present results of our first attempt to model these problems in 3-D using our finite difference time domain (FDTD) code. 10 refs., 9 figs

  10. Numerical multistep methods for the efficient solution of quantum mechanics and related problems

    International Nuclear Information System (INIS)

    Anastassi, Z.A.; Simos, T.E.

    2009-01-01

    In this paper we present the recent development in the numerical integration of the Schroedinger equation and related systems of ordinary differential equations with oscillatory solutions, such as the N-body problem. We examine several types of multistep methods (explicit, implicit, predictor-corrector, hybrid) and several properties (P-stability, trigonometric fitting of various orders, phase fitting, high phase-lag order, algebraic order). We analyze the local truncation error and the stability of the methods. The error for the Schroedinger equation is also presented, which reveals the relation of the error to the energy. The efficiency of the methods is evaluated through the integration of five problems. Figures are presented and analyzed and some general conclusions are made. Code written in Maple is given for the development of all methods analyzed in this paper. Also the subroutines written in Matlab, that concern the integration of the methods, are presented.

  11. A numerical approach of thermal problems coupling fluid solid and radiation in complex geometries

    International Nuclear Information System (INIS)

    Peniguel, C.; Rupp, I.

    1995-11-01

    In many industrial problems, heat transfer does play an important part. Quite often, radiation, convection and radiation are present simultaneously. This paper presents the numerical tool handling simultaneously these phenomena. Fluid is tackled by the finite element code N3S, radiation (restricted to a non participating medium) and conduction are handled with SYRTHES respectively by a radiosity method and a finite element method. The main originality of the product is that meshes used to solve each phenomenon are completely independent. This allows users to choose the most appropriate spatial discretization for each part or phenomenon. This flexibility requires of course robust and fast data exchange procedures (temperature, convective flux, radiative flux) between the independent grids. This operation is done automatically by the code SYRTHES. One simple problem illustrating the interest of this development is presented at the end of the paper. (author). 6 refs., 8 figs

  12. Penalty methods for the numerical solution of American multi-asset option problems

    Science.gov (United States)

    Nielsen, Bjørn Fredrik; Skavhaug, Ola; Tveito, Aslak

    2008-12-01

    We derive and analyze a penalty method for solving American multi-asset option problems. A small, non-linear penalty term is added to the Black-Scholes equation. This approach gives a fixed solution domain, removing the free and moving boundary imposed by the early exercise feature of the contract. Explicit, implicit and semi-implicit finite difference schemes are derived, and in the case of independent assets, we prove that the approximate option prices satisfy some basic properties of the American option problem. Several numerical experiments are carried out in order to investigate the performance of the schemes. We give examples indicating that our results are sharp. Finally, the experiments indicate that in the case of correlated underlying assets, the same properties are valid as in the independent case.

  13. Aspects of numerical modelling in expert practice; Aspekte der numerischen Modellierung in der gutachterlichen Praxis

    Energy Technology Data Exchange (ETDEWEB)

    Schaedler, G.

    1998-01-01

    Referring to a relatively restricted field, namely the preparation of expertises in small-scale climatology and air hygiene, the paper wants to give insight into the methods of, and the problems associated with, the numerical modellings used. Frequently occurring tasks are described, the numerical models used are briefly outlined, and some of the problems are discussed which are encountered when using these models. (orig./KW) [Deutsch] Der vorliegende Aufsatz soll am Beispiel eines relativ eng umgrenzten Themenkreises, naemlich der gutachterlichen Taetigkeit im Bereich der kleinraeumigen Klimatologie und Lufthygiene, einen Einblick in die Methoden und Probleme der dabei eingesetzten numerischen Modellierung geben. Zunaechst werden haeufig auftretende Aufgabenstellungen dargestellt, dann die verwendeten numerischen Modelle kurz vorgestellt und schliesslich einige der Probleme angesprochen, die sich beim praktischen Einsatz dieser Modelle stellen. (orig./KW)

  14. Methods tuned on the physical problem. A way to improve numerical codes

    International Nuclear Information System (INIS)

    Ixaru, L.Gr.

    2010-01-01

    We consider the problem on how the numerical methods tuned on the physical problem can contribute to the enhancement of the performance of the codes. We illustrate this on two simple cases: solution of time independent one-dimensional Schroedinger equation, and the computation of integrals with oscillatory integrands. In both cases the tuned versions bring a massive gain in accuracy at negligible extra cost. We presented two simple problems where successive levels of tuning enhance significantly the accuracy at negligible extra cost. These problems should be seen as representing only some illustrations on how the codes can be improved but we must also mention that in many cases tuned versions still have to be developed. Just for a suggestion, quadrature formulae which involve the integrand and a number of successive derivatives of this exist, but no formula is available when some of these derivatives are missing, for example when we dispose of y and y'' but not of y'. A direct application will be on the case when the integrand involves the solution of the Schrodinger equation by the method of Numerov. (author)

  15. Numerical method for multigroup one-dimensional SN eigenvalue problems with no spatial truncation error

    International Nuclear Information System (INIS)

    Abreu, M.P.; Filho, H.A.; Barros, R.C.

    1993-01-01

    The authors describe a new nodal method for multigroup slab-geometry discrete ordinates S N eigenvalue problems that is completely free from all spatial truncation errors. The unknowns in the method are the node-edge angular fluxes, the node-average angular fluxes, and the effective multiplication factor k eff . The numerical values obtained for these quantities are exactly those of the dominant analytic solution of the S N eigenvalue problem apart from finite arithmetic considerations. This method is based on the use of the standard balance equation and two nonstandard auxiliary equations. In the nonmultiplying regions, e.g., the reflector, we use the multigroup spectral Green's function (SGF) auxiliary equations. In the fuel regions, we use the multigroup spectral diamond (SD) auxiliary equations. The SD auxiliary equation is an extension of the conventional auxiliary equation used in the diamond difference (DD) method. This hybrid characteristic of the SD-SGF method improves both the numerical stability and the convergence rate

  16. Theory and algorithms for solving large-scale numerical problems. Application to the management of electricity production

    International Nuclear Information System (INIS)

    Chiche, A.

    2012-01-01

    This manuscript deals with large-scale optimization problems, and more specifically with solving the electricity unit commitment problem arising at EDF. First, we focused on the augmented Lagrangian algorithm. The behavior of that algorithm on an infeasible convex quadratic optimization problem is analyzed. It is shown that the algorithm finds a point that satisfies the shifted constraints with the smallest possible shift in the sense of the Euclidean norm and that it minimizes the objective on the corresponding shifted constrained set. The convergence to such a point is realized at a global linear rate, which depends explicitly on the augmentation parameter. This suggests us a rule for determining the augmentation parameter to control the speed of convergence of the shifted constraint norm to zero. This rule has the advantage of generating bounded augmentation parameters even when the problem is infeasible. As a by-product, the algorithm computes the smallest translation in the Euclidean norm that makes the constraints feasible. Furthermore, this work provides solution methods for stochastic optimization industrial problems decomposed on a scenario tree, based on the progressive hedging algorithm introduced by [Rockafellar et Wets, 1991]. We also focus on the convergence of that algorithm. On the one hand, we offer a counter-example showing that the algorithm could diverge if its augmentation parameter is iteratively updated. On the other hand, we show how to recover the multipliers associated with the non-dualized constraints defined on the scenario tree from those associated with the corresponding constraints of the scenario subproblems. Their convergence is also analyzed for convex problems. The practical interest of theses solutions techniques is corroborated by numerical experiments performed on the electric production management problem. We apply the progressive hedging algorithm to a realistic industrial problem. More precisely, we solve the French medium

  17. Probabilistic numerical methods for high-dimensional stochastic control and valuation problems on electricity markets

    International Nuclear Information System (INIS)

    Langrene, Nicolas

    2014-01-01

    This thesis deals with the numerical solution of general stochastic control problems, with notable applications for electricity markets. We first propose a structural model for the price of electricity, allowing for price spikes well above the marginal fuel price under strained market conditions. This model allows to price and partially hedge electricity derivatives, using fuel forwards as hedging instruments. Then, we propose an algorithm, which combines Monte-Carlo simulations with local basis regressions, to solve general optimal switching problems. A comprehensive rate of convergence of the method is provided. Moreover, we manage to make the algorithm parsimonious in memory (and hence suitable for high dimensional problems) by generalizing to this framework a memory reduction method that avoids the storage of the sample paths. We illustrate this on the problem of investments in new power plants (our structural power price model allowing the new plants to impact the price of electricity). Finally, we study more general stochastic control problems (the control can be continuous and impact the drift and volatility of the state process), the solutions of which belong to the class of fully nonlinear Hamilton-Jacobi-Bellman equations, and can be handled via constrained Backward Stochastic Differential Equations, for which we develop a backward algorithm based on control randomization and parametric optimizations. A rate of convergence between the constraPned BSDE and its discrete version is provided, as well as an estimate of the optimal control. This algorithm is then applied to the problem of super replication of options under uncertain volatilities (and correlations). (author)

  18. Current problems of foreign practice-related educational psychology

    Directory of Open Access Journals (Sweden)

    A.D. Andreeva

    2012-09-01

    Full Text Available The article regards the questions of scientific-methodological provision of psychologist’s activity in an educational settlement which are urgent for the activity of practical educational psychologist in Russia as well. The presented information concerns the psychologist’s particular strands of work which can be both developing (development of ABM and psycho-correcting (reasons and forms of school phobias, bullying displays, lying. The ethical problems of psychologist’s work with families namely in case of the parent-child conflicts is also reviewed in the article.

  19. Report of the panel on practical problems in actinide biology

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Practical problems are classified as the need to make operational decisions, the need for regulatory assessment either of individual facilities or of generic actions, and the overt appearance of radiobiological effects in man or radioactivity in man or the environment. Topics discussed are as follows: simulated reactor accident; long term effects of low doses; effects of repeated exposures to actinides; inhaled uranium mine air contaminants; metabolism and dosimetry; environmental equilibrium models; patterns of alpha dosimetry; internal dose calculations; interfaces between actinide biology and environmental studies; removal of actinides deposited in the body; and research needs related to uranium isotopes

  20. An Investigation into Students' Difficulties in Numerical Problem Solving Questions in High School Biology Using a Numeracy Framework

    Science.gov (United States)

    Scott, Fraser J.

    2016-01-01

    The "mathematics problem" is a well-known source of difficulty for students attempting numerical problem solving questions in the context of science education. This paper illuminates this problem from a biology education perspective by invoking Hogan's numeracy framework. In doing so, this study has revealed that the contextualisation of…

  1. Is Treating Motor Problems in DCD Just a Matter of Practice and More Practice?

    Science.gov (United States)

    Schoemaker, Marina M; Smits-Engelsman, Bouwien C M

    Developmental coordination disorder (DCD) is often called a motor learning deficit. The question addressed in this paper is whether improvement of motor skills is just a matter of mere practice. Without any kind of intervention, children with DCD do not improve their motor skills generally, whereas they do improve after task-oriented intervention. Merely offering children the opportunity to practice motor skills, for instance by playing active video games, did lead to improved motor performance according to recent research findings, but to a lesser extent than task-oriented intervention. We argue that children with DCD lack the required motor problem-solving skills necessary to further improve their performance. Explicit motor teaching with an emphasis on developing these problem-solving skills is a necessary ingredient of intervention in DCD, leveraging the effectiveness of intervention above that of mere practicing.

  2. Parameter estimation in IMEX-trigonometrically fitted methods for the numerical solution of reaction-diffusion problems

    Science.gov (United States)

    D'Ambrosio, Raffaele; Moccaldi, Martina; Paternoster, Beatrice

    2018-05-01

    In this paper, an adapted numerical scheme for reaction-diffusion problems generating periodic wavefronts is introduced. Adapted numerical methods for such evolutionary problems are specially tuned to follow prescribed qualitative behaviors of the solutions, making the numerical scheme more accurate and efficient as compared with traditional schemes already known in the literature. Adaptation through the so-called exponential fitting technique leads to methods whose coefficients depend on unknown parameters related to the dynamics and aimed to be numerically computed. Here we propose a strategy for a cheap and accurate estimation of such parameters, which consists essentially in minimizing the leading term of the local truncation error whose expression is provided in a rigorous accuracy analysis. In particular, the presented estimation technique has been applied to a numerical scheme based on combining an adapted finite difference discretization in space with an implicit-explicit time discretization. Numerical experiments confirming the effectiveness of the approach are also provided.

  3. Two numerical methods for the solution of two-dimensional eddy current problems

    International Nuclear Information System (INIS)

    Biddlecombe, C.S.

    1978-07-01

    A general method for the solution of eddy current problems in two dimensions - one component of current density and two of magnetic field, is reported. After examining analytical methods two numerical methods are presented. Both solve the two dimensional, low frequency limit of Maxwell's equations for transient eddy currents in conducting material, which may be permeable, in the presence of other non-conducting permeable material. Both solutions are expressed in terms of the magnetic vector potential. The first is an integral equation method, using zero order elements in the discretisation of the unknown source regions. The other is a differential equation method, using a first order finite element mesh, and the Galerkin weighted residual procedure. The resulting equations are solved as initial-value problems. Results from programs based on each method are presented showing the power and limitations of the methods and the range of problems solvable. The methods are compared and recommendations are made for choosing between them. Suggestions are made for improving both methods, involving boundary integral techniques. (author)

  4. The tangential breast match plane: Practical problems and solutions

    International Nuclear Information System (INIS)

    Norris, M.

    1989-01-01

    The three-field breast set-up, in which tangential oblique opposed fields are joined to an anterior supraclavicular field, has been the method of choice for treatment of breast cancer for many years. In the last several years many authors have suggested refinements to the technique that improve the accuracy with which fields join at a match plane. The three-field breast set-up, using a rotatable half-beam block is the technique used at our institution. In instituting this procedure, several practical problems were encountered. Due to the small collimator rotation angles used it is possible to clinically reverse the collimator angle without observing an error noticeable on fluoroscopy. A second error can occur when the table base angle is used to compensate for the incorrect collimator rotation. These potential sources of error can be avoided if a programmable calculator or computer program is used to assist the dosimetrist during the simulation. Utilization of fluoroscopy, digital table position displays and a caliper provide accurate input for the computer program. This paper will present a hybrid procedure that combines practical set-up procedures with the mathematical calculation of ideal angles to result in an accurate and practical approach to breast simulation

  5. RCM vs. traditional maintenance practice: Some problems when RCM is introduced for the first time

    International Nuclear Information System (INIS)

    Shishkova, I.V.

    2000-01-01

    The presentation is focused on some problems which arise when RCM is introduced for first time. These problems were identified from EQE-Bulgaria experience when RCM meters were discussed for first time at number of plants and organizations. Mainly the following problem areas are covered: The first group of problems arise from the nature of RCM. The RCM is referred to as a 'new concept', 'new philosophy', 'new maintenance system', etc. On the other hand, RCM has nothing new - it is a structure of established maintenance techniques. It leads to some difficulties to explain what exactly is the 'new' to a managerial body and to a staff of a plant which has its own established maintenance system running for years. This group of problems covers in particular the following points: RCM definition vs. 'Traditional' Maintenance definition; The understanding about the relationship between inherent reliability and the desired performance of an asset; Difficulties to prove the advantages of RCM and the benefits of its implementation in case RCM is not a country-wide practice. The second problem area is the terminology. The RCM concept is developed and described mainly in reference documents written in English. The direct translation into a certain language introduces some misunderstanding especially if there is no established terminology in the corresponding national language. The first major task is to get clear understanding about relationship between RCM terminology and the terms used in the current maintenance practice defined in the national standards. The next problem area is the availability or unavailability of relevant reliability plant specific data. We found that people tend to trust more the 'numerical' (quantitative) results rather than the qualitative ones. So efforts should be spent to explain and even to prove the advantages and disadvantages of both qualitative and quantitative approaches as well as to show clearly the relation between qualitative and

  6. A numerical algorithm for optimal feedback gains in high dimensional linear quadratic regulator problems

    Science.gov (United States)

    Banks, H. T.; Ito, K.

    1991-01-01

    A hybrid method for computing the feedback gains in linear quadratic regulator problem is proposed. The method, which combines use of a Chandrasekhar type system with an iteration of the Newton-Kleinman form with variable acceleration parameter Smith schemes, is formulated to efficiently compute directly the feedback gains rather than solutions of an associated Riccati equation. The hybrid method is particularly appropriate when used with large dimensional systems such as those arising in approximating infinite-dimensional (distributed parameter) control systems (e.g., those governed by delay-differential and partial differential equations). Computational advantages of the proposed algorithm over the standard eigenvector (Potter, Laub-Schur) based techniques are discussed, and numerical evidence of the efficacy of these ideas is presented.

  7. Numerical solution of the model problem of CCRF-discharge at atmospheric pressure

    Directory of Open Access Journals (Sweden)

    Zheltukhin Viktor

    2017-01-01

    Full Text Available This work describes a 1D mathematical model of capacitive coupled RF discharge between symmetrical electrodes in argon at atmospheric pressure in a local approximation. Electrons, atomic and molecular ions, metastable atoms and argon dimmers as well as ground-state atoms are considered. A simplified diagram of argon excited states when two metastable and two resonance states are replaced with the uniform level. Such diagram is frequently used to simulate argon plasma due to efficient mixing of these layers at electron impacts. Velocity factors of electron impact processes were calculated using Boltzmann equation with a glance to electron-electron collisions. This work describes numerical algorithm of mathematical model implementation, which is based on finite-dimensional approximation of the problem using difference schemes together with iteration process. The software was developed to implement iterative processes using MatLab. Characteristics of atmospheric pressure capacitive coupled RF discharge at interelectrod distance 20 mm are calculated.

  8. Features of the Numerical Solution of Thermal Destruction Fuel Pins Problems in the Fast Reactor

    Science.gov (United States)

    Usov, E. V.; Butov, A. A.; Klimonov, I. A.; Chuhno, V. I.; Nikolaenko, A. V.; Zhdanov, V. S.; Pribaturin, N. A.; Strizhov, V. F.

    2017-11-01

    In this paper the description of the basic equations which can be used for calculation of melting of fuel and cladding of the fast reactor, moving of the melt on a fuel pin surface and its solidification is presented. The special attention is given speed of calculation algorithms and fidelity of the phenomena which are observed at a stage of severe accidents in fast reactors. For check of working capacity of initial models, numerical calculations of Stefan-type problems on front movement of melting/solidification in cylindrical geometry are presented. Comparison with the solutions received by known analytical methods is executed. For validation of the numerical realization of calculation algorithms the analysis is carried out and experiments in which melting of the model fuel pins of fast reactors was studied are chosen. On the basis of the chosen experiments calculation schemes taking into account initial and boundary conditions are prepared and modeling is performed. Modeling results are shown in the present paper. Estimation of calculation error of the basic physical parameters is done by results of the modeling and conclusions are drawn on a correctness of algorithms operation.

  9. Experimental investigation and numerical modeling of carbonation process in reinforced concrete structures Part II. Practical applications

    International Nuclear Information System (INIS)

    Saetta, Anna V.; Vitaliani, Renato V.

    2005-01-01

    The mathematical-numerical method developed by the authors to predict the corrosion initiation time of reinforced concrete structures due to carbonation process, recalled in Part I of this work, is here applied to some real cases. The final aim is to develop and test a practical method for determining the durability characteristics of existing buildings liable to carbonation, as well as estimating the corrosion initiation time of a building at the design stage. Two industrial sheds with different ages and located in different areas have been analyzed performing both experimental tests and numerical analyses. Finally, a case of carbonation-induced failure in a prestressed r.c. beam is presented

  10. Numerical and analytical solutions for problems relevant for quantum computers; Numerische und analytische Loesungen fuer Quanteninformatisch-relevante Probleme

    Energy Technology Data Exchange (ETDEWEB)

    Spoerl, Andreas

    2008-06-05

    Quantum computers are one of the next technological steps in modern computer science. Some of the relevant questions that arise when it comes to the implementation of quantum operations (as building blocks in a quantum algorithm) or the simulation of quantum systems are studied. Numerical results are gathered for variety of systems, e.g. NMR systems, Josephson junctions and others. To study quantum operations (e.g. the quantum fourier transform, swap operations or multiply-controlled NOT operations) on systems containing many qubits, a parallel C++ code was developed and optimised. In addition to performing high quality operations, a closer look was given to the minimal times required to implement certain quantum operations. These times represent an interesting quantity for the experimenter as well as for the mathematician. The former tries to fight dissipative effects with fast implementations, while the latter draws conclusions in the form of analytical solutions. Dissipative effects can even be included in the optimisation. The resulting solutions are relaxation and time optimised. For systems containing 3 linearly coupled spin (1)/(2) qubits, analytical solutions are known for several problems, e.g. indirect Ising couplings and trilinear operations. A further study was made to investigate whether there exists a sufficient set of criteria to identify systems with dynamics which are invertible under local operations. Finally, a full quantum algorithm to distinguish between two knots was implemented on a spin(1)/(2) system. All operations for this experiment were calculated analytically. The experimental results coincide with the theoretical expectations. (orig.)

  11. Numerical Solution of Mixed Problems of the Theory of Elasticity with One-Sided Constraints

    Directory of Open Access Journals (Sweden)

    I. V. Stankevich

    2017-01-01

    Full Text Available The paper deals with the application features of the finite element technologies to solve the problems of elasticity with one-sided constraints. On the one hand, the area of this study is determined by the fact that many critical parts and assemblies of mechanical and power engineering constructions have a significant contact within some given surface. To assess the strength and the life of these parts and assemblies, reliable stress-strain state data are demandable. Data on the stress-strain state can be obtained using the contemporary mathematical modeling means, e.g., finite element technology.To solve the problems of the theory of elasticity with one-sided constraints, a method of finite elements in a traditional classical form can be used, but it is necessary to consider some of its shortcomings. The most significant one is an approximation of the tensile stress and strain, as well as a considerably lower order of convergence of the approximation for stresses and strains as compared to displacements. Improving the accuracy through increasing a density of the finite element models and/or the transition to more complex approximations is not always optimal, because increasing a dimension of the discrete problem leads to a significant computational cost and demand for expensive computing resources.One of the alternatives in numerical analysis of contact problems of the elasticity theory is to use the mixed variational formulations of the finite element method in which stresses and/or strains appear in the resolving equations along with displacements as equal unknown. A major positive factor when using the mixed formulations of the finite element method is reduction of the approximation error of stress and strain, which leads to a more accurate assessment of the stress-strain state in comparison with the classical approach of the finite element method in the form of the method of displacements.Besides, mixed schemes of the finite element method

  12. Numerical solution to a multi-dimensional linear inverse heat conduction problem by a splitting-based conjugate gradient method

    International Nuclear Information System (INIS)

    Dinh Nho Hao; Nguyen Trung Thanh; Sahli, Hichem

    2008-01-01

    In this paper we consider a multi-dimensional inverse heat conduction problem with time-dependent coefficients in a box, which is well-known to be severely ill-posed, by a variational method. The gradient of the functional to be minimized is obtained by aids of an adjoint problem and the conjugate gradient method with a stopping rule is then applied to this ill-posed optimization problem. To enhance the stability and the accuracy of the numerical solution to the problem we apply this scheme to the discretized inverse problem rather than to the continuous one. The difficulties with large dimensions of discretized problems are overcome by a splitting method which only requires the solution of easy-to-solve one-dimensional problems. The numerical results provided by our method are very good and the techniques seem to be very promising.

  13. Practical problems of third party liability connected with nuclear installations

    International Nuclear Information System (INIS)

    Lacroix, F.

    1975-01-01

    A special regime of liability for nuclear damage was established by the Paris Convention, 1960, and the Vienna Convention, 1963. The same basic principles are embodied in both Conventions. Some discrepancies, however, still exist between them despite the adoption of an additional protocol to the Paris Convention in 1964 for harmonization purposes. Practical problems facing insurers and suggestions for suitable solutions are presented. International transport of nuclear material raises, in particular, complex issues. With regard to civil liability arising out of the carriage of nuclear material by sea, a possible conflict between maritime transport conventions and nuclear liability conventions was resolved by the Brussels' Convention, 1971. Wider ratification of the nuclear conventions appears to be the only way for coping with some remaining difficulties, in particular with respect to nuclear material in transit

  14. Role of beliefs and emotions in numerical problem solving in university physics education

    Science.gov (United States)

    Bodin, Madelen; Winberg, Mikael

    2012-06-01

    Numerical problem solving in classical mechanics in university physics education offers a learning situation where students have many possibilities of control and creativity. In this study, expertlike beliefs about physics and learning physics together with prior knowledge were the most important predictors of the quality of performance of a task with many degrees of freedom. Feelings corresponding to control and concentration, i.e., emotions that are expected to trigger students’ intrinsic motivation, were also important in predicting performance. Unexpectedly, intrinsic motivation, as indicated by enjoyment and interest, together with students’ personal interest and utility value beliefs did not predict performance. This indicates that although a certain degree of enjoyment is probably necessary, motivated behavior is rather regulated by integration and identification of expertlike beliefs about learning and are more strongly associated with concentration and control during learning and, ultimately, with high performance. The results suggest that the development of students’ epistemological beliefs is important for students’ ability to learn from realistic problem-solving situations with many degrees of freedom in physics education.

  15. Role of beliefs and emotions in numerical problem solving in university physics education

    Directory of Open Access Journals (Sweden)

    Madelen Bodin

    2012-02-01

    Full Text Available Numerical problem solving in classical mechanics in university physics education offers a learning situation where students have many possibilities of control and creativity. In this study, expertlike beliefs about physics and learning physics together with prior knowledge were the most important predictors of the quality of performance of a task with many degrees of freedom. Feelings corresponding to control and concentration, i.e., emotions that are expected to trigger students’ intrinsic motivation, were also important in predicting performance. Unexpectedly, intrinsic motivation, as indicated by enjoyment and interest, together with students’ personal interest and utility value beliefs did not predict performance. This indicates that although a certain degree of enjoyment is probably necessary, motivated behavior is rather regulated by integration and identification of expertlike beliefs about learning and are more strongly associated with concentration and control during learning and, ultimately, with high performance. The results suggest that the development of students’ epistemological beliefs is important for students’ ability to learn from realistic problem-solving situations with many degrees of freedom in physics education.

  16. Analysis of selected problems of biomass combustion process in batch boilers - experimental and numerical approach

    Science.gov (United States)

    Szubel, Mateusz

    2016-03-01

    It is possible to list numerous groups of heating units that are used in households, such as boilers, stoves and units used as supporting heat sources, namely fireplaces. In each case, however, the same operational problems may be evoked [1]. To understand the causes of energy losses in a boiler system, a proper definition of significant elements of the unit's heat balance is necessary. In the group of energy losses, the flue gas loss and the incomplete combustion loss are the most significant factors. The problem with the loss resulting from incomplete combustion, which is related to the presence of combustible substances in the exhaust, is especially significant in case of biomass boilers [2, 3]. The paper presents results of the research and the optimisation of the biomass combustion process in the 180 kW batch boiler. The studies described have been focused on the reduction of the pollutants emission, which was primarily realised by the modifications of the air feeding system. Results of the experiments and the CFD simulations have been compared and discussed. Both in case of the model as well as the experiment, positive influence of the modifications on the emission have been observed.

  17. Analysis of selected problems of biomass combustion process in batch boilers - experimental and numerical approach

    Directory of Open Access Journals (Sweden)

    Szubel Mateusz

    2016-01-01

    Full Text Available It is possible to list numerous groups of heating units that are used in households, such as boilers, stoves and units used as supporting heat sources, namely fireplaces. In each case, however, the same operational problems may be evoked [1]. To understand the causes of energy losses in a boiler system, a proper definition of significant elements of the unit’s heat balance is necessary. In the group of energy losses, the flue gas loss and the incomplete combustion loss are the most significant factors. The problem with the loss resulting from incomplete combustion, which is related to the presence of combustible substances in the exhaust, is especially significant in case of biomass boilers [2, 3]. The paper presents results of the research and the optimisation of the biomass combustion process in the 180 kW batch boiler. The studies described have been focused on the reduction of the pollutants emission, which was primarily realised by the modifications of the air feeding system. Results of the experiments and the CFD simulations have been compared and discussed. Both in case of the model as well as the experiment, positive influence of the modifications on the emission have been observed.

  18. New numerical methods for open-loop and feedback solutions to dynamic optimization problems

    Science.gov (United States)

    Ghosh, Pradipto

    The topic of the first part of this research is trajectory optimization of dynamical systems via computational swarm intelligence. Particle swarm optimization is a nature-inspired heuristic search method that relies on a group of potential solutions to explore the fitness landscape. Conceptually, each particle in the swarm uses its own memory as well as the knowledge accumulated by the entire swarm to iteratively converge on an optimal or near-optimal solution. It is relatively straightforward to implement and unlike gradient-based solvers, does not require an initial guess or continuity in the problem definition. Although particle swarm optimization has been successfully employed in solving static optimization problems, its application in dynamic optimization, as posed in optimal control theory, is still relatively new. In the first half of this thesis particle swarm optimization is used to generate near-optimal solutions to several nontrivial trajectory optimization problems including thrust programming for minimum fuel, multi-burn spacecraft orbit transfer, and computing minimum-time rest-to-rest trajectories for a robotic manipulator. A distinct feature of the particle swarm optimization implementation in this work is the runtime selection of the optimal solution structure. Optimal trajectories are generated by solving instances of constrained nonlinear mixed-integer programming problems with the swarming technique. For each solved optimal programming problem, the particle swarm optimization result is compared with a nearly exact solution found via a direct method using nonlinear programming. Numerical experiments indicate that swarm search can locate solutions to very great accuracy. The second half of this research develops a new extremal-field approach for synthesizing nearly optimal feedback controllers for optimal control and two-player pursuit-evasion games described by general nonlinear differential equations. A notable revelation from this development

  19. Numerical Analysis of Turbulent Flow around Tube Bundle by Applying CAD Best Practice Guideline

    International Nuclear Information System (INIS)

    Lee, Gong Hee; Bang, Young Seok; Woo, Sweng Woong; Cheng, Ae Ju

    2013-01-01

    In this study, the numerical analysis of a turbulent flow around both a staggered and an incline tube bundle was conducted using Annoys Cfx V. 13, a commercial CAD software. The flow was assumed to be steady, incompressible, and isothermal. According to the CAD Best Practice Guideline, the sensitivity study for grid size, accuracy of the discretization scheme for convection term, and turbulence model was conducted, and its result was compared with the experimental data to estimate the applicability of the CAD Best Practice Guideline. It was concluded that the CAD Best Practice Guideline did not always guarantee an improvement in the prediction performance of the commercial CAD software in the field of tube bundle flow

  20. Evaluate the accuracy of the numerical solution of hydrogeological problems of mass transfer

    Directory of Open Access Journals (Sweden)

    Yevhrashkina G.P.

    2014-12-01

    Full Text Available In the hydrogeological task on quantifying pollution of aquifers the error are starting add up with moment organization of regime observation network as a source of information on the pollution of groundwater in order to evaluate migration options for future prognosis calculations. Optimum element regime observation network should consist of three drill holes on the groundwater flow at equal distances from one another and transversely to the flow of the three drill holes, and at equal distances. If the target of observation drill holes coincides with the stream line on which will then be decided by direct migration task, the error will be minimal. The theoretical basis and results of numerical experiments to assess the accuracy of direct predictive tasks planned migration of groundwater in the area of full water saturation. For the vadose zone, we consider problems of vertical salt transport moisture. All studies were performed by comparing the results of fundamental and approximate solutions in a wide range of characteristics of the processes, which are discussed in relation to ecological and hydrogeological conditions of mining regions on the example of the Western Donbass.

  1. Development of a Numerical Model for Orthogonal Cutting. Discussion about the Sensitivity to Friction Problem

    Science.gov (United States)

    San Juan, M.; de la Iglesia, J. M.; Martín, O.; Santos, F. J.

    2009-11-01

    In despite of the important progresses achieved in the knowledge of cutting processes, the study of certain aspects has undergone the very limitations of the experimental means: temperature gradients, frictions, contact, etc… Therefore, the development of numerical models is a valid tool as a first approach to study of those problems. In the present work, a calculation model under Abaqus Explicit code is developed to represent the orthogonal cutting of AISI 4140 steel. A bidimensional simulation under plane strain conditions, which is considered as adiabatic due to the high speed of the material flow, is chosen. The chip separation is defined by means of a fracture law that allows complex simulations of tool penetration in the workpiece. The strong influence of friction on cutting is proved, therefore a very good definition of materials behaviour laws could be obtained, but an erroneous value of friction coefficient could notably reduce the reliability. Considering the difficulty of checking the friction models used in the simulation, from the tests carried out habitually, the most efficacious way to characterize the friction would be to combine simulation models with cutting tests.

  2. Method of independent timesteps in the numerical solution of initial value problems

    International Nuclear Information System (INIS)

    Porter, A.P.

    1976-01-01

    In the numerical solution of initial-value problems in several independent variables, the timestep is controlled, especially in the presence of shocks, by a small portion of the logical mesh, what one may call the crisis zone. One is frustrated by the necessity of doing in the whole mesh frequent calculations required by only a small part of the mesh. It is shown that it is possible to choose different timesteps natural to different parts of the mesh and to advance each zone in time only as often as is appropriate to that zone's own natural timestep. Prior work is reviewed and for the first time an investigation of the conditions for well-posedness, consistency and stability in independent timesteps is presented; a new method results. The prochronic and parachronic Cauchy surfaces are identified; and the reasons (well-posedness) for constraining the Cauchy surfaces to be prochronic (as distinct from the method of Grandey), that is, to lie prior to the time of the crisis zone (the zone of least timestep), are indicated. Stability (in the maximum norm) of parabolic equations and (in the L2 norm) of hyperbolic equations is reviewed, without restricting the treatment to linear equations or constant coefficients, and stability of the new method is proven in this framework. The details of the method of independent timesteps, the rules for choosing timesteps and for deciding when to update and when to skip zones, and the method of joining adjacent regions of differing timestep are described. The stability of independent timestep difference schemes is analyzed and exhibited. The economic advantages of the method, which often amount to an order-of-magnitude decrease in running time relative to conventional or implicit difference methods, are noted

  3. Method of independent timesteps in the numerical solution of initial value problems

    Energy Technology Data Exchange (ETDEWEB)

    Porter, A.P.

    1976-07-21

    In the numerical solution of initial-value problems in several independent variables, the timestep is controlled, especially in the presence of shocks, by a small portion of the logical mesh, what one may call the crisis zone. One is frustrated by the necessity of doing in the whole mesh frequent calculations required by only a small part of the mesh. It is shown that it is possible to choose different timesteps natural to different parts of the mesh and to advance each zone in time only as often as is appropriate to that zone's own natural timestep. Prior work is reviewed and for the first time an investigation of the conditions for well-posedness, consistency and stability in independent timesteps is presented; a new method results. The prochronic and parachronic Cauchy surfaces are identified; and the reasons (well-posedness) for constraining the Cauchy surfaces to be prochronic (as distinct from the method of Grandey), that is, to lie prior to the time of the crisis zone (the zone of least timestep), are indicated. Stability (in the maximum norm) of parabolic equations and (in the L2 norm) of hyperbolic equations is reviewed, without restricting the treatment to linear equations or constant coefficients, and stability of the new method is proven in this framework. The details of the method of independent timesteps, the rules for choosing timesteps and for deciding when to update and when to skip zones, and the method of joining adjacent regions of differing timestep are described. The stability of independent timestep difference schemes is analyzed and exhibited. The economic advantages of the method, which often amount to an order-of-magnitude decrease in running time relative to conventional or implicit difference methods, are noted.

  4. Do practice nurse solve future GP capacity problems?

    NARCIS (Netherlands)

    Lamkaddem, M.; Haan, J. de; Bakker, D. de

    2003-01-01

    Background: Task delegation is viewed as an important policy instrument to counter foreseen future shortages in GP capacity in the Netherlands. Therefore, a national programme to introduce practice nurses in general practice was launched in 1998 by the National Association of General Practice. In

  5. Teacher Practices with Toddlers during Social Problem Solving Opportunities

    Science.gov (United States)

    Gloeckler, Lissy; Cassell, Jennifer

    2012-01-01

    This article explores how teachers can foster an environment that facilitates social problem solving when toddlers experience conflict, emotional dysregulation, and aggression. This article examines differences in child development and self-regulation outcomes when teachers engage in problem solving "for" toddlers and problem solving "with"…

  6. A Problem-Solving Model for Literacy Coaching Practice

    Science.gov (United States)

    Toll, Cathy A.

    2017-01-01

    Literacy coaches are more effective when they have a clear plan for their collaborations with teachers. This article provides details of such a plan, which involves identifying a problem, understanding the problem, deciding what to do differently, and trying something different. For each phase of the problem-solving model, there are key tasks for…

  7. A Family of Symmetric Linear Multistep Methods for the Numerical Solution of the Schroedinger Equation and Related Problems

    International Nuclear Information System (INIS)

    Anastassi, Z. A.; Simos, T. E.

    2010-01-01

    We develop a new family of explicit symmetric linear multistep methods for the efficient numerical solution of the Schroedinger equation and related problems with oscillatory solution. The new methods are trigonometrically fitted and have improved intervals of periodicity as compared to the corresponding classical method with constant coefficients and other methods from the literature. We also apply the methods along with other known methods to real periodic problems, in order to measure their efficiency.

  8. Use of exact albedo conditions in numerical methods for one-dimensional one-speed discrete ordinates eigenvalue problems

    International Nuclear Information System (INIS)

    Abreu, M.P. de

    1994-01-01

    The use of exact albedo boundary conditions in numerical methods applied to one-dimensional one-speed discrete ordinates (S n ) eigenvalue problems for nuclear reactor global calculations is described. An albedo operator that treats the reflector region around a nuclear reactor core implicitly is described and exactly was derived. To illustrate the method's efficiency and accuracy, it was used conventional linear diamond method with the albedo option to solve typical model problems. (author)

  9. Embedding Number-Combinations Practice Within Word-Problem Tutoring

    Science.gov (United States)

    Powell, Sarah R.; Fuchs, Lynn S.; Fuchs, Douglas

    2012-01-01

    Two aspects of mathematics with which students with mathematics learning difficulty (MLD) often struggle are word problems and number-combination skills. This article describes a math program in which students receive instruction on using algebraic equations to represent the underlying problem structure for three word-problem types. Students also learn counting strategies for answering number combinations that they cannot retrieve from memory. Results from randomized-control trials indicated that embedding the counting strategies for number combinations produces superior word-problem and number-combination outcomes for students with MLD beyond tutoring programs that focus exclusively on number combinations or word problems. PMID:22661880

  10. Numerical Solution of the Blasius Viscous Flow Problem by Quartic B-Spline Method

    Directory of Open Access Journals (Sweden)

    Hossein Aminikhah

    2016-01-01

    Full Text Available A numerical method is proposed to study the laminar boundary layer about a flat plate in a uniform stream of fluid. The presented method is based on the quartic B-spline approximations with minimizing the error L2-norm. Theoretical considerations are discussed. The computed results are compared with some numerical results to show the efficiency of the proposed approach.

  11. Numerical analysis of melting/solidification phenomena using a moving boundary problem analysis method X-FEM

    International Nuclear Information System (INIS)

    Uchibori, Akihiro; Ohshima, Hiroyuki

    2008-01-01

    A numerical analysis method for melting/solidification phenomena has been developed to evaluate a feasibility of several candidate techniques in the nuclear fuel cycle. Our method is based on the eXtended Finite Element Method (X-FEM) which has been used for moving boundary problems. Key technique of the X-FEM is to incorporate signed distance function into finite element interpolation to represent a discontinuous gradient of the temperature at a moving solid-liquid interface. Construction of the finite element equation, the technique of quadrature and the method to solve the equation are reported here. The numerical solutions of the one-dimensional Stefan problem, solidification in a two-dimensional square corner and melting of pure gallium are compared to the exact solutions or to the experimental data. Through these analyses, validity of the newly developed numerical analysis method has been demonstrated. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Theoretical stability in coefficient inverse problems for general hyperbolic equations with numerical reconstruction

    Science.gov (United States)

    Yu, Jie; Liu, Yikan; Yamamoto, Masahiro

    2018-04-01

    In this article, we investigate the determination of the spatial component in the time-dependent second order coefficient of a hyperbolic equation from both theoretical and numerical aspects. By the Carleman estimates for general hyperbolic operators and an auxiliary Carleman estimate, we establish local Hölder stability with either partial boundary or interior measurements under certain geometrical conditions. For numerical reconstruction, we minimize a Tikhonov functional which penalizes the gradient of the unknown function. Based on the resulting variational equation, we design an iteration method which is updated by solving a Poisson equation at each step. One-dimensional prototype examples illustrate the numerical performance of the proposed iteration.

  14. Practices of Legitimacy and the Problem of Artistic Research

    Science.gov (United States)

    Matcham, David

    2014-01-01

    This paper examines the positioning of art practice as a mode of research through various legitimising practices. While frequently fruitful, the imperative to make art justify itself as a form of research in order to achieve legitimacy allows that in art which does not engage in negative dialectics to slip from view. The possibility of the kind of…

  15. A new numerical scheme for non uniform homogenized problems: Application to the non linear Reynolds compressible equation

    Directory of Open Access Journals (Sweden)

    Buscaglia Gustavo C.

    2001-01-01

    Full Text Available A new numerical approach is proposed to alleviate the computational cost of solving non-linear non-uniform homogenized problems. The article details the application of the proposed approach to lubrication problems with roughness effects. The method is based on a two-parameter Taylor expansion of the implicit dependence of the homogenized coefficients on the average pressure and on the local value of the air gap thickness. A fourth-order Taylor expansion provides an approximation that is accurate enough to be used in the global problem solution instead of the exact dependence, without introducing significant errors. In this way, when solving the global problem, the solution of local problems is simply replaced by the evaluation of a polynomial. Moreover, the method leads naturally to Newton-Raphson nonlinear iterations, that further reduce the cost. The overall efficiency of the numerical methodology makes it feasible to apply rigorous homogenization techniques in the analysis of compressible fluid contact considering roughness effects. Previous work makes use of an heuristic averaging technique. Numerical comparison proves that homogenization-based methods are superior when the roughness is strongly anisotropic and not aligned with the flow direction.

  16. Numerical research of the optimal control problem in the semi-Markov inventory model

    Energy Technology Data Exchange (ETDEWEB)

    Gorshenin, Andrey K. [Institute of Informatics Problems, Russian Academy of Sciences, Vavilova str., 44/2, Moscow, Russia MIREA, Faculty of Information Technology (Russian Federation); Belousov, Vasily V. [Institute of Informatics Problems, Russian Academy of Sciences, Vavilova str., 44/2, Moscow (Russian Federation); Shnourkoff, Peter V.; Ivanov, Alexey V. [National research university Higher school of economics, Moscow (Russian Federation)

    2015-03-10

    This paper is devoted to the numerical simulation of stochastic system for inventory management products using controlled semi-Markov process. The results of a special software for the system’s research and finding the optimal control are presented.

  17. Numerical research of the optimal control problem in the semi-Markov inventory model

    International Nuclear Information System (INIS)

    Gorshenin, Andrey K.; Belousov, Vasily V.; Shnourkoff, Peter V.; Ivanov, Alexey V.

    2015-01-01

    This paper is devoted to the numerical simulation of stochastic system for inventory management products using controlled semi-Markov process. The results of a special software for the system’s research and finding the optimal control are presented

  18. Auditing Management Practices in Schools: Recurring Communication Problems and Solutions

    Science.gov (United States)

    Zwijze-Koning, Karen H.; de Jong, Menno D. T.

    2009-01-01

    Purpose: Over the past ten years, most Dutch high schools have been confronted with mergers, curriculum reforms, and managerial changes. As a result, the pressure on the schools' communication systems has increased and several problems have emerged. This paper aims to examine recurring clusters of communication problems in high schools.…

  19. Asymptotic solutions of numerical transport problems in optically thick, diffusive regimes II

    International Nuclear Information System (INIS)

    Larsen, E.W.; Morel, J.E.

    1989-01-01

    In a recent article (Larsen, Morel, and Miller, J. Comput. Phys. 69, 283 (1987)), a theoretical method is described for assessing the accuracy of transport differencing schemes in highly scattering media with optically thick spatial meshes. In the present article, this method is extended to enable one to determine the accuracy of such schemes in the presence of numerically unresolved boundary layers. Numerical results are presented that demonstrate the validity and accuracy of our analysis. copyright 1989 Academic Press, Inc

  20. Continuity of the direct and inverse problems in one-dimensional scattering theory and numerical solution of the inverse problem

    International Nuclear Information System (INIS)

    Moura, C.A. de.

    1976-09-01

    We propose an algorithm for computing the potential V(x) associated to the one-dimensional Schroedinger operator E identical to - d 2 /dx 2 + V(x) -infinite < x< infinite from knowledge of the S.matrix, more exactly, of one of the reelection coefficients. The convergence of the algorithm is guaranteed by the stability results obtained for both the direct and inverse problems

  1. The problem of diagnostic variability in general practice.

    Science.gov (United States)

    Crombie, D L; Cross, K W; Fleming, D M

    1992-08-01

    The aim was to examine the scale, source, and relevance of variation between general practices in respect of the rates with which patients consulted with illnesses falling in each of several diagnostic groups. This study involved a general practice morbidity survey conducted over two years, 1970-72. All patients who consulted their general practitioners were identified and the number of these who consulted with diagnoses attributable to each of the 18 main chapters of the International classification of diseases were counted. Patients who consulted for more than one diagnosis within a chapter were counted once only; those who consulted for one or more diagnoses in each of several chapters were counted once for each chapter. This was a national survey involving general practitioners in England and Wales. The study involved 214,524 patients from 53 selected general practices (115 doctors) who were registered with their general practitioners for the whole of the year 1970-71 and for whom their morbidity data had been linked with their social data from the 1971 census. Using the numbers of patients on the practice lists as denominators, practice patient consulting rates (PPCR) were calculated for each practice and for each ICD chapter. Variability in chapter PPCR was examined by calculating coefficients of variation and, after allowance for random variation, coefficients of residual variation. There were large interpractice (doctor) variations in all chapter rates. These variations were only marginally attributable to: chance; different age, sex and social class mixes of practice populations; geographical locations; and practice organisation. The rates were, however, consistent from one year to the next for any one practice. Approximately half of the interpractice (doctor) diagnostic variability was associated with overall patient consulting behaviour. When the effects of this behaviour were discounted, any major residual diagnostic variability was confined largely to

  2. Analytical and numerical study of validation test-cases for multi-physic problems: application to magneto-hydro-dynamic

    Directory of Open Access Journals (Sweden)

    D Cébron

    2016-04-01

    Full Text Available The present paper is concerned with the numerical simulation of Magneto-Hydro-Dynamic (MHD problems with industrial tools. MHD has receivedattention some twenty to thirty years ago as a possible alternative inpropulsion applications; MHD propelled ships have even been designed forthat purpose. However, such propulsion systems have been proved of lowefficiency and fundamental researches in the area have progressivelyreceived much less attention over the past decades. Numerical simulationof MHD problem could however provide interesting solutions in the field ofturbulent flow control. The development of recent efficient numericaltechniques for multi-physic applications provide promising tool for theengineer for that purpose. In the present paper, some elementary testcases in laminar flow with magnetic forcing terms are analysed; equationsof the coupled problem are exposed, analytical solutions are derived ineach case and are compared to numerical solutions obtained with anumerical tool for multi-physic applications. The present work can be seenas a validation of numerical tools (based on the finite element method foracademic as well as industrial application purposes.

  3. Numerical solution of fully developed heat transfer problem with constant wall temperature and application to isosceles triangle and parabolic ducts

    International Nuclear Information System (INIS)

    Karabulut, Halit; Ipci, Duygu; Cinar, Can

    2016-01-01

    Highlights: • A numerical method has been developed for fully developed flows with constant wall temperature. • The governing equations were transformed to boundary fitted coordinates. • The Nusselt number of parabolic duct has been investigated. • Validation of the numerical method has been made by comparing published data. - Abstract: In motor-vehicles the use of more compact radiators have several advantages such as; improving the aerodynamic form of cars, reducing the weight and volume of the cars, reducing the material consumption and environmental pollutions, and enabling faster increase of the engine coolant temperature after starting to run and thereby improving the thermal efficiency. For the design of efficient and compact radiators, the robust determination of the heat transfer coefficient becomes imperative. In this study the external heat transfer coefficient of the radiator has been investigated for hydrodynamically and thermally fully developed flows in channels with constant wall temperature. In such situation the numerical treatment of the problem results in a trivial solution. To find a non-trivial solution the problem is treated either as an eigenvalue problem or as a thermally developing flow problem. In this study a numerical solution procedure has been developed and the heat transfer coefficients of the fully developed flow in triangular and parabolic air channels were investigated. The governing equations were transformed to boundary fitted coordinates and numerically solved. The non-trivial solution was obtained by means of guessing the temperature of any grid point within the solution domain. The correction of the guessed temperature was performed via smoothing the temperature profile on a line passing through the mentioned grid point. Results were compared with literature data and found to be consistent.

  4. Some problems with the food packaging practices in Ghana ...

    African Journals Online (AJOL)

    ... lack of standards and specifications and environmental issues have all been discussed. The effect of the increasing use of plastics as the main packaging material ... How these problems impact on the country's drive towards food security as ...

  5. Drug-related problems and pharmacy interventions in community practice

    DEFF Research Database (Denmark)

    Westerlund, Tommy; Almarsdóttir, Anna Birna; Melander, Arne

    1999-01-01

    Objectives. (1) To document types and number of drug-related problems identified by community pharmacy personnel in Sweden; (2) to determine relationships among the types and number of problems identified and the gender, age and number of prescribed drugs in patients; and (3) to document the inte......Objectives. (1) To document types and number of drug-related problems identified by community pharmacy personnel in Sweden; (2) to determine relationships among the types and number of problems identified and the gender, age and number of prescribed drugs in patients; and (3) to document...... the interventions made by pharmacy personnel with patients and prescribers. Method. Random samples of pharmacists, prescriptionists and pharmacy technicians were drawn nationwide in Sweden; 144 (63 per cent) of the employees fulfilling the inclusion criteria agreed to take part. The participants documented drug......-related problems, interventions and patient variables on a data collection form, and tallied the number of patients they served on another form. Setting. One hundred and sixteen community pharmacies and 12 outpatient hospital pharmacies. Key findings. One problem or more was identified among 2.5 per cent...

  6. Numerical simulation for a two-phase porous medium flow problem with rate independent hysteresis

    International Nuclear Information System (INIS)

    Brokate, M.; Botkin, N.D.; Pykhteev, O.A.

    2012-01-01

    The paper is devoted to the numerical simulation of a multiphase flow in porous medium with a hysteretic relation between the capillary pressures and the saturations of the phases. The flow model we use is based on Darcy's law. The hysteretic relation between the capillary pressures and the saturations is described by a play-type hysteresis operator. We propose a numerical algorithm for treating the arising system of equations, discuss finite element schemes and present simulation results for the case of two phases.

  7. Numerical simulation for a two-phase porous medium flow problem with rate independent hysteresis

    KAUST Repository

    Brokate, M.

    2012-05-01

    The paper is devoted to the numerical simulation of a multiphase flow in porous medium with a hysteretic relation between the capillary pressures and the saturations of the phases. The flow model we use is based on Darcys law. The hysteretic relation between the capillary pressures and the saturations is described by a play-type hysteresis operator. We propose a numerical algorithm for treating the arising system of equations, discuss finite element schemes and present simulation results for the case of two phases. © 2011 Elsevier B.V. All rights reserved.

  8. Numerical methods for solution of some nonlinear problems of mathematical physics

    International Nuclear Information System (INIS)

    Zhidkov, E.P.

    1981-01-01

    The continuous analog of the Newton method and its application to some nonlinear problems of mathematical physics using a computer is considered. It is shown that the application of this method in JINR to the wide range of nonlinear problems has shown its universality and high efficiency [ru

  9. Numerical Analysis of Forth-Order Boundary Value Problems in Fluid Mechanics and Mathematics

    DEFF Research Database (Denmark)

    Hosseinzadeh, E.; Barari, Amin; Fouladi, F.

    2011-01-01

    In this paper He's variational iteration method is used to solve some examples of linear and non-linear forth-order boundary value problems. The first problem compared with homotopy analysis method solution and the other ones with the exact solution. The results show the high accuracy and speed o...

  10. Numerical analysis of fourth-order boundary value problems in fluid mechanics and mathematics

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Barari, Amin; Fouladi, Fama

    2010-01-01

    In this paper He's variational iteration method is used to solve some examples of linear and non-linear forth-order boundary value problems. The first problem compared with homotopy analysis method solution and the other ones with the exact solution. The results show the high accuracy and speed o...

  11. New Developments of Computational Fluid Dynamics and Their Applications to Practical Engineering Problems

    Science.gov (United States)

    Chen, Hudong

    2001-06-01

    There have been considerable advances in Lattice Boltzmann (LB) based methods in the last decade. By now, the fundamental concept of using the approach as an alternative tool for computational fluid dynamics (CFD) has been substantially appreciated and validated in mainstream scientific research and in industrial engineering communities. Lattice Boltzmann based methods possess several major advantages: a) less numerical dissipation due to the linear Lagrange type advection operator in the Boltzmann equation; b) local dynamic interactions suitable for highly parallel processing; c) physical handling of boundary conditions for complicated geometries and accurate control of fluxes; d) microscopically consistent modeling of thermodynamics and of interface properties in complex multiphase flows. It provides a great opportunity to apply the method to practical engineering problems encountered in a wide range of industries from automotive, aerospace to chemical, biomedical, petroleum, nuclear, and others. One of the key challenges is to extend the applicability of this alternative approach to regimes of highly turbulent flows commonly encountered in practical engineering situations involving high Reynolds numbers. Over the past ten years, significant efforts have been made on this front at Exa Corporation in developing a lattice Boltzmann based commercial CFD software, PowerFLOW. It has become a useful computational tool for the simulation of turbulent aerodynamics in practical engineering problems involving extremely complex geometries and flow situations, such as in new automotive vehicle designs world wide. In this talk, we present an overall LB based algorithm concept along with certain key extensions in order to accurately handle turbulent flows involving extremely complex geometries. To demonstrate the accuracy of turbulent flow simulations, we provide a set of validation results for some well known academic benchmarks. These include straight channels, backward

  12. Fostering Scientific and Numerate Practices in Journalism to Support Rapid Public Learning

    Directory of Open Access Journals (Sweden)

    Louise Yarnall

    2017-01-01

    Full Text Available Journalism has the potential––and arguably the mandate––to expand public understanding of societally important phenomena. However, some methods for more effectively educating the public have been persistently underutilized: in particular, embedding informative numerical rates and efficient scientific explanations in news reports. In the current era of disrupting and downsizing the news business, the challenges to using such methods have only increased. To address this problem, this article seeks to (a raise awareness about the psychological reasons that help explain why it is crucial to use such elements in news reports, and (b exhibit some methods for doing so that require modest effort. Building on a review of relevant psychological literatures, principles, and existing reporting methods, we describe findings from a series of cognitive-scientific studies that demonstrate how using key––and relatively minimal––scientific and numerical elements can enhance public learning from news reports. We conclude by also describing curricula and resources designed to help journalists and bloggers use these methods.

  13. Solution of stochastic media transport problems using a numerical quadrature-based method

    International Nuclear Information System (INIS)

    Pautz, S. D.; Franke, B. C.; Prinja, A. K.; Olson, A. J.

    2013-01-01

    We present a new conceptual framework for analyzing transport problems in random media. We decompose such problems into stratified subproblems according to the number of material pseudo-interfaces within realizations. For a given subproblem we assign pseudo-interface locations in each realization according to product quadrature rules, which allows us to deterministically generate a fixed number of realizations. Quadrature integration of the solutions of these realizations thus approximately solves each subproblem; the weighted superposition of solutions of the subproblems approximately solves the general stochastic media transport problem. We revisit some benchmark problems to determine the accuracy and efficiency of this approach in comparison to randomly generated realizations. We find that this method is very accurate and fast when the number of pseudo-interfaces in a problem is generally low, but that these advantages quickly degrade as the number of pseudo-interfaces increases. (authors)

  14. A metaheuristic for a numerical approximation to the mass transfer problem

    Directory of Open Access Journals (Sweden)

    Avendaño-Garrido Martha L.

    2016-12-01

    Full Text Available This work presents an improvement of the approximation scheme for the Monge-Kantorovich (MK mass transfer problem on compact spaces, which is studied by Gabriel et al. (2010, whose scheme discretizes the MK problem, reduced to solve a sequence of finite transport problems. The improvement presented in this work uses a metaheuristic algorithm inspired by scatter search in order to reduce the dimensionality of each transport problem. The new scheme solves a sequence of linear programming problems similar to the transport ones but with a lower dimension. The proposed metaheuristic is supported by a convergence theorem. Finally, examples with an exact solution are used to illustrate the performance of our proposal.

  15. A Probabilistic-Numerical Approximation for an Obstacle Problem Arising in Game Theory

    International Nuclear Information System (INIS)

    Grün, Christine

    2012-01-01

    We investigate a two-player zero-sum stochastic differential game in which one of the players has more information on the game than his opponent. We show how to construct numerical schemes for the value function of this game, which is given by the solution of a quasilinear partial differential equation with obstacle.

  16. One Language, Two Number-Word Systems and Many Problems: Numerical Cognition in the Czech Language

    Science.gov (United States)

    Pixner, S.; Zuber, J.; Hermanova, V.; Kaufmann, L.; Nuerk, H.-C.; Moeller, K.

    2011-01-01

    Comparing numerical performance between different languages does not only mean comparing different number-word systems, but also implies a comparison of differences regarding culture or educational systems. The Czech language provides the remarkable opportunity to disentangle this confound as there exist two different number-word systems within…

  17. A Probabilistic-Numerical Approximation for an Obstacle Problem Arising in Game Theory

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, Christine, E-mail: christine.gruen@univ-brest.fr [Laboratoire de Mathematiques de Brest UMR 6205 (France)

    2012-12-15

    We investigate a two-player zero-sum stochastic differential game in which one of the players has more information on the game than his opponent. We show how to construct numerical schemes for the value function of this game, which is given by the solution of a quasilinear partial differential equation with obstacle.

  18. Numerical Laplace inversion in problems of elastodynamics: Comparison of four algorithms

    Czech Academy of Sciences Publication Activity Database

    Adámek, V.; Valeš, František; Červ, Jan

    2017-01-01

    Roč. 113, November (2017), s. 120-129 ISSN 0965-9978 R&D Projects: GA ČR(CZ) GAP101/12/2315 Institutional support: RVO:61388998 Keywords : inverse Laplace transform * numerical algorithm * wave propagation * multi-precision computation * Maple code Subject RIV: BI - Acoustics OBOR OECD: Acoustics Impact factor: 3.000, year: 2016

  19. Numerical simulation for a two-phase porous medium flow problem with rate independent hysteresis

    KAUST Repository

    Brokate, M.; Botkin, N.D.; Pykhteev, O.A.

    2012-01-01

    The paper is devoted to the numerical simulation of a multiphase flow in porous medium with a hysteretic relation between the capillary pressures and the saturations of the phases. The flow model we use is based on Darcys law. The hysteretic

  20. The Problems of Practice: Bricolage as a Metaphor for Teachers' Work and Learning

    Science.gov (United States)

    Scribner, Jay Paredes

    2005-01-01

    In this article the author uses Levi-Strauss' (1966) metaphor of Bricolage to examine how teachers, not policymakers, make sense of their "problems of practice" in three United States high schools. The article also examines how teachers address these problems of practice. It concludes by underscoring the disconnect between teachers' and…

  1. Tensile Split Hopkinson Bar Technique: Numerical Analysis of the Problem of Wave Disturbance and Specimen Geometry Selection

    Directory of Open Access Journals (Sweden)

    Panowicz Robert

    2016-09-01

    Full Text Available A method of tensile testing of materials in dynamic conditions based on a slightly modified compressive split Hopkinson bar system using a shoulder is described in this paper. The main goal was to solve, with the use of numerical modelling, the problem of wave disturbance resulting from application of a shoulder, as well as the problem of selecting a specimen geometry that enables to study the phenomenon of high strain-rate failure in tension. It is shown that, in order to prevent any interference of disturbance with the required strain signals at a given recording moment, the positions of the strain gages on the bars have to be correctly chosen for a given experimental setup. Besides, it is demonstrated that - on the basis of simplified numerical analysis - an appropriate gage length and diameter of a material specimen for failure testing in tension can be estimated.

  2. Problem drinking - detection and assessment in general practice.

    Science.gov (United States)

    Demirkol, Apo; Haber, Paul; Conigrave, Katherine

    2011-08-01

    Alcohol has long been an integral part of the social life of many Australians. However, alcohol is associated with significant harm to drinkers, and also to nondrinkers. This article explores the role of the general practitioner in the detection and assessment of problem drinking. Excessive alcohol use is a major public health problem and the majority of people who drink excessively go undetected. General practitioners are in a good position to detect excessive alcohol consumption; earlier intervention can help improve outcomes. AUDIT-C is an effective screening tool for the detection of problem drinking. National Health and Medical Research Council guidelines suggest that no more than two standard drinks on each occasion will keep lifetime risk of death from alcohol related disease or injury at a low level. Once an alcohol problem is detected it is important to assess for alcohol dependence, other substance use, motivation to change, psychiatric comorbidities and examination and investigation findings that may be associated with excessive alcohol use. A comprehensive assessment of the impact and risk of harm of the patient's drinking to themselves and others is vital, and may require several consultations.

  3. Aspects of Girls' Friendships: Practice Implications for Internalizing Problems

    Science.gov (United States)

    Ralph, Leslie E. R.; Epkins, Catherine C.

    2015-01-01

    Background: Children's friendship quality is a particularly important risk or protective factor for internalizing problems and loneliness. Past research indicates that relationship satisfaction is related to perceived similarity; however, it is unclear whether this relation is seen in girls' friendship quality and whether this relation is…

  4. [Problems of ethics, deontology and esthetics in pathology practice].

    Science.gov (United States)

    Shmurun, R I

    1997-01-01

    Relationships between pathologists on the one hand and clinicians, patients asking for histological slides, relatives of the deceased persons on the other are extremely complicated and need special attention. Pathology service should not be considered as second-rate. Ethic problems in the pathology service are not yet properly dealt in the literature.

  5. Solving Large Scale Crew Scheduling Problems in Practice

    NARCIS (Netherlands)

    E.J.W. Abbink (Erwin); L. Albino; T.A.B. Dollevoet (Twan); D. Huisman (Dennis); J. Roussado; R.L. Saldanha

    2010-01-01

    textabstractThis paper deals with large-scale crew scheduling problems arising at the Dutch railway operator, Netherlands Railways (NS). NS operates about 30,000 trains a week. All these trains need a driver and a certain number of guards. Some labor rules restrict the duties of a certain crew base

  6. Associations between yoga practice and joint problems: a cross-sectional survey among 9151 Australian women.

    Science.gov (United States)

    Lauche, Romy; Schumann, Dania; Sibbritt, David; Adams, Jon; Cramer, Holger

    2017-07-01

    Yoga exercises have been associated with joint problems recently, indicating that yoga practice might be potentially dangerous for joint health. This study aimed to analyse whether regular yoga practice is associated with the frequency of joint problems in upper middle-aged Australian women. Women aged 62-67 years from the Australian Longitudinal Study on Women's Health (ALSWH) were questioned in 2013 whether they experienced regular joint pain or problems in the past 12 months and whether they regularly practiced yoga. Associations of joint problems with yoga practice were analysed using Chi-squared tests and multiple logistic regression modelling. Of 9151 women, 29.8% reported regular problems with stiff or painful joints, and 15.2, 11.9, 18.1 and 15.9% reported regular problems with shoulders, hips, knees and feet, respectively, in the past 12 months. Yoga was practiced sometimes by 10.1% and often by 8.4% of women. Practicing yoga was not associated with upper or lower limb joint problems. No association between yoga practice and joint problems has been identified. Further studies are warranted for conclusive judgement of benefits and safety of yoga in relation to joint problems.

  7. NUMERICAL SOLUTION OF SINGULAR INVERSE NODAL PROBLEM BY USING CHEBYSHEV POLYNOMIALS

    OpenAIRE

    NEAMATY, ABDOLALI; YILMAZ, EMRAH; AKBARPOOR, SHAHRBANOO; DABBAGHIAN, ABDOLHADI

    2017-01-01

    In this study, we consider Sturm-Liouville problem in two cases: the first case having no singularity and the second case having a singularity at zero. Then, we calculate the eigenvalues and the nodal points and present the uniqueness theorem for the solution of the inverse problem by using a dense subset of the nodal points in two given cases. Also, we use Chebyshev polynomials of the first kind for calculating the approximate solution of the inverse nodal problem in these cases. Finally, we...

  8. On some examples of pollutant transport problems solved numerically using the boundary element method

    Science.gov (United States)

    Azis, Moh. Ivan; Kasbawati; Haddade, Amiruddin; Astuti Thamrin, Sri

    2018-03-01

    A boundary element method (BEM) is obtained for solving a boundary value problem of homogeneous anisotropic media governed by diffusion-convection equation. The application of the BEM is shown for two particular pollutant transport problems of Tello river and Unhas lake in Makassar Indonesia. For the two particular problems a variety of the coefficients of diffusion and the velocity components are taken. The results show that the solutions vary as the parameters change. And this suggests that one has to be careful in measuring or determining the values of the parameters.

  9. A numerical scheme for singularly perturbed reaction-diffusion problems with a negative shift via numerov method

    Science.gov (United States)

    Dinesh Kumar, S.; Nageshwar Rao, R.; Pramod Chakravarthy, P.

    2017-11-01

    In this paper, we consider a boundary value problem for a singularly perturbed delay differential equation of reaction-diffusion type. We construct an exponentially fitted numerical method using Numerov finite difference scheme, which resolves not only the boundary layers but also the interior layers arising from the delay term. An extensive amount of computational work has been carried out to demonstrate the applicability of the proposed method.

  10. Numerical solution of system of boundary value problems using B-spline with free parameter

    Science.gov (United States)

    Gupta, Yogesh

    2017-01-01

    This paper deals with method of B-spline solution for a system of boundary value problems. The differential equations are useful in various fields of science and engineering. Some interesting real life problems involve more than one unknown function. These result in system of simultaneous differential equations. Such systems have been applied to many problems in mathematics, physics, engineering etc. In present paper, B-spline and B-spline with free parameter methods for the solution of a linear system of second-order boundary value problems are presented. The methods utilize the values of cubic B-spline and its derivatives at nodal points together with the equations of the given system and boundary conditions, ensuing into the linear matrix equation.

  11. On the Problem of Constructing Routes, Part II: Methodology and Numerical Example

    Directory of Open Access Journals (Sweden)

    Linis V. K.

    2017-09-01

    Full Text Available We consider a periodic aviation schedule which is a finite collection of flights with given arrival/departure times. For this schedule, we solve the problem of finding the minimal number of aircrafts needed to carry out the flights. The crucial role in solving this problem is played by so-called deficit function (DFs defined as the difference between departures and arrivals on interval [0,t] for each terminal.

  12. The streamline upwind Petrov-Galerkin stabilising method for the numerical solution of highly advective problems

    Directory of Open Access Journals (Sweden)

    Carlos Humberto Galeano Urueña

    2009-05-01

    Full Text Available This article describes the streamline upwind Petrov-Galerkin (SUPG method as being a stabilisation technique for resolving the diffusion-advection-reaction equation by finite elements. The first part of this article has a short analysis of the importance of this type of differential equation in modelling physical phenomena in multiple fields. A one-dimensional description of the SUPG me- thod is then given to extend this basis to two and three dimensions. The outcome of a strongly advective and a high numerical complexity experiment is presented. The results show how the version of the implemented SUPG technique allowed stabilised approaches in space, even for high Peclet numbers. Additional graphs of the numerical experiments presented here can be downloaded from www.gnum.unal.edu.co.

  13. An efficient approach to the numerical solution of rate-independent problems with nonconvex energies

    Czech Academy of Sciences Publication Activity Database

    Bartels, S.; Kružík, Martin

    2011-01-01

    Roč. 9, č. 3 (2011), s. 1275-1300 ISSN 1540-3459 R&D Projects: GA AV ČR IAA100750802 Grant - others:GA ČR(CZ) GAP201/10/0357 Institutional research plan: CEZ:AV0Z10750506 Keywords : numerical solution * nonconvexity Subject RIV: BA - General Mathematics Impact factor: 2.009, year: 2011 http://library.utia.cas.cz/separaty/2011/MTR/kruzik-0364707.pdf

  14. Numerical simulation of increasing initial perturbations of a bubble in the bubble–shock interaction problem

    Energy Technology Data Exchange (ETDEWEB)

    Korneev, Boris [Moscow Institute of Physics and Technology, 9 Institutsky lane, Dolgoprudny 141700 (Russian Federation); Levchenko, Vadim, E-mail: boris.korneev@phystech.edu [Keldysh Institute of Applied Mathematics, 4 Miusskaya square, Moscow 125047 (Russian Federation)

    2016-12-15

    A set of numerical experiments on the interaction between a planar shock wave and a spherical bubble with a slightly perturbed surface is considered. Spectral analysis of the instability growth is carried out and three-dimensional Euler equations of fluid dynamics are chosen as the mathematical model for the process. The equations are solved via the Runge–Kutta discontinuous Galerkin method and the special DiamondTorre algorithm for multi-GPU implementation is used. (paper)

  15. Current problems and subjects on numerical analysis of earthquake geotechnical engineering. For seamless analysis

    International Nuclear Information System (INIS)

    Yoshida, Taiki

    2016-01-01

    There are continuum and discontinuum analyses in the evaluation of seismic stability of surrounding slope in nuclear power plant facility. However, we cannot rationally evaluate such seismic stability due to excessive conservative margin of the results by each analysis. If we can simulate the behavior from small to large deformation by hybridizing them, we can contribute not only to the rationalization of the slope stability evaluation but also the enhancement of evaluation precision in the numerical analysis. In this review, the previous numerical analyses and application cases of them in earthquake geotechnical engineering were classified into three categories, that is, continuum analysis, discontinuum one and the hybridizing process to identify their research themes. The present review has revealed that the research themes are the standardization of condition for conversion, construction of the technique to determine parameters related to conversion and the reasonable physical property set of DEM(Distinct Element Method) after conversion. Our future work will be development of a numerical analysis code hybridizing continuum and discontinuum analyses based on the identified research themes. (author)

  16. One language, two number-word systems and many problems: numerical cognition in the Czech language.

    Science.gov (United States)

    Pixner, S; Zuber, J; Heřmanová, V; Kaufmann, L; Nuerk, H-C; Moeller, K

    2011-01-01

    Comparing numerical performance between different languages does not only mean comparing different number-word systems, but also implies a comparison of differences regarding culture or educational systems. The Czech language provides the remarkable opportunity to disentangle this confound as there exist two different number-word systems within the same language: for instance, "25" can be either coded in non-inverted order "dvadsetpät" [twenty-five] or in inverted order "pätadvadset" [five-and-twenty]. To investigate the influence of the number-word system on basic numerical processing within one culture, 7-year-old Czech-speaking children had to perform a transcoding task (i.e., writing Arabic numbers to dictation) in both number-word systems. The observed error pattern clearly indicated that the structure of the number-word system determined transcoding performance reliably: In the inverted number-word system about half of all errors were inversion-related. In contrast, hardly any inversion-related errors occurred in the non-inverted number-word system. We conclude that the development of numerical cognition does not only depend on cultural or educational differences, but is indeed related to the structure and transparency of a given number-word system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Vertigo in neurological practice (common problems of diagnosis and treatment

    Directory of Open Access Journals (Sweden)

    Olga Vladimirovna Kosivtsova

    2012-01-01

    Full Text Available Most patients with vertigo seek neurological advice. In spite of the availability of current examination techniques, a differential diagnosis of vertigo is not frequently made. The paper discusses the terminology and classification of vertigo and clinical methods for diagnosing central and peripheral vestibulopathies. It considers the common problems of management of patients with diseases of the central and peripheral vestibular systems, the use of piracetam and other drugs to stimulate rehabilitation.

  18. PROBLEMS OF IMPLEMENTATION 5S PRACTICES IN AN INDUSTRIAL COMPANY

    Directory of Open Access Journals (Sweden)

    Beata GALA

    2013-10-01

    Full Text Available 5S is a one of the tools of Lean Management enabling to organize workplace in an effective way. It could be implemented in all the spheres of the company. The article provides the theoretic description of Lean Management and 5S and also shows a case study based on gained experience. The author also describe the problems occured during the implementation of the 5S.

  19. Problems and opportunity of personality inventories in clinical - psychological practice

    Directory of Open Access Journals (Sweden)

    Emil Benedik

    2002-12-01

    Full Text Available The article deals with possibilities and problems of usage of personality inventories in psychological diagnostic of persons with "heavy pathology", from aspect of validity and applicability in the first place. Personality inventories are usually designed for health population. By their usage in clinical psychology we often meet problems like specific tendencies when answering defined questions. This could be the result of situational factors but also the impact of their disorders and personality. The possibilities of classical interpretation of results are in this way limited. Do we have the opportunity of development of the diagnostic instruments that we could, not only recognise, but use such deformations (which represent cognitive style or defence of person in diagnostic purpose? The MMPI-2, most famous inventory in this field, offer us great aid, especially because its items are selected empirically. By the analysis of its items from aspect of sensing and localisation of subjects problems, we found differences between clinical scales which represent patients of different clinical groups. These differences are in accordance with psychoanalytical assumptions about characteristics of sensing self and other people.

  20. Medication management and practices in prison for people with mental health problems: a qualitative study

    OpenAIRE

    Bowen, Robert A; Rogers, Anne; Shaw, Jennifer

    2009-01-01

    Abstract Background Common mental health problems are prevalent in prison and the quality of prison health care provision for prisoners with mental health problems has been a focus of critical scrutiny. Currently, health policy aims to align and integrate prison health services and practices with those of the National Health Service (NHS). Medication management is a key aspect of treatment for patients with a mental health problem. The medication practices of patients and staff are therefore ...

  1. A Problem in Online Interpersonal Skills Training: Do Learners Practice Skills?

    Science.gov (United States)

    Doo, Min Young

    2006-01-01

    One problem found when teaching interpersonal skills online is learners' lack of opportunity for skill practice. The online learning environment is deficient in face-to-face interaction, and opportunities for self-regulation make it difficult to ensure learners practice skills despite the positive effects of such practice on skill improvement. The…

  2. Radioecological problems, and how they are tackled in practice

    International Nuclear Information System (INIS)

    Bleck-Neuhaus, J.

    1981-01-01

    Evaluation of radioecological hazards is an issue that is in the field of tension between science, law, and government. Licences granted by the authorities, the author states, often are based on expert opinions that rely on incorrect data, or on values obtained by taking the mean, which falsifies real conditions. Examples are given. There is another fact that puts on edge to discussions, namely current practice in this field which accepts that the relevant authorities are given two-fold competency, being the executive power with regard to the Atomic Energy Act on the one hand, and an instrument for implementing the government's strategies to support the utilization of nuclear energy. (DG) [de

  3. Applications of integral equation methods for the numerical solution of magnetostatic and eddy current problems

    International Nuclear Information System (INIS)

    Trowbridge, C.W.

    1976-06-01

    Various integral equation methods are described. For magnetostatic problems three formulations are considered in detail, (a) the direct solution method for the magnetisation distribution in permeable materials, (b) a method based on a scalar potential and (c) the use of an integral equation derived from Green's Theorem, i.e. the so-called Boundary Integral Method (BIM). In the case of (a) results are given for two-and three-dimensional non-linear problems with comparisons against measurement. For methods (b) and (c) which both lead to a more economic use of the computer than (a) some preliminary results are given for simple cases. For eddy current problems various methods are discussed and some results are given from a computer program based on a vector potential formulation. (author)

  4. Applications of integral equation methods for the numerical solution of magnetostatic and eddy current problems

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, C W

    1976-06-01

    Various integral equation methods are described. For magnetostatic problems three formulations are considered in detail, (a) the direct solution method for the magnetisation distribution in permeable materials, (b) a method based on a scalar potential, and (c) the use of an integral equation derived from Green's Theorem, i.e. the so-called Boundary Integral Method (BIM). In the case of (a) results are given for two-and three-dimensional non-linear problems with comparisons against measurement. For methods (b) and (c), which both lead to a more economical use of the computer than (a), some preliminary results are given for simple cases. For eddy current problems various methods are discussed and some results are given from a computer program based on a vector potential formulation.

  5. EMOTIONAL MATURITY OF PERSONALITY: THE PRACTICAL PROBLEM OF PSYCHOLOGICAL DIAGNOSIS

    OpenAIRE

    O. I. Afonina

    2013-01-01

    In the dif?cult conditions of the contemporary society which are far from being favorable to maintain one’s emotional and physical health the problem of development and achievement of emotional maturity as a factor of the well-being is getting more signi?cant. Based on the theoretical concepts of different scientists who de?ned the construct of emotional maturity three groups of psychological methods for assessing emotional maturity are analyzed. The ?rst group includes the methods that are u...

  6. Numerical and analytical approaches to an advection-diffusion problem at small Reynolds number and large Péclet number

    Science.gov (United States)

    Fuller, Nathaniel J.; Licata, Nicholas A.

    2018-05-01

    Obtaining a detailed understanding of the physical interactions between a cell and its environment often requires information about the flow of fluid surrounding the cell. Cells must be able to effectively absorb and discard material in order to survive. Strategies for nutrient acquisition and toxin disposal, which have been evolutionarily selected for their efficacy, should reflect knowledge of the physics underlying this mass transport problem. Motivated by these considerations, in this paper we discuss the results from an undergraduate research project on the advection-diffusion equation at small Reynolds number and large Péclet number. In particular, we consider the problem of mass transport for a Stokesian spherical swimmer. We approach the problem numerically and analytically through a rescaling of the concentration boundary layer. A biophysically motivated first-passage problem for the absorption of material by the swimming cell demonstrates quantitative agreement between the numerical and analytical approaches. We conclude by discussing the connections between our results and the design of smart toxin disposal systems.

  7. Numerical solution of sixth-order boundary-value problems using Legendre wavelet collocation method

    Science.gov (United States)

    Sohaib, Muhammad; Haq, Sirajul; Mukhtar, Safyan; Khan, Imad

    2018-03-01

    An efficient method is proposed to approximate sixth order boundary value problems. The proposed method is based on Legendre wavelet in which Legendre polynomial is used. The mechanism of the method is to use collocation points that converts the differential equation into a system of algebraic equations. For validation two test problems are discussed. The results obtained from proposed method are quite accurate, also close to exact solution, and other different methods. The proposed method is computationally more effective and leads to more accurate results as compared to other methods from literature.

  8. Numerical solution of problems concerning the thermal convection of a variable-viscosity liquid

    Science.gov (United States)

    Zherebiatev, I. F.; Lukianov, A. T.; Podkopaev, Iu. L.

    A stabilizing-correction scheme is constructed for integrating the fourth-order equation describing the dynamics of a viscous incompressible liquid. As an example, a solution is obtained to the problem of the solidification of a liquid in a rectangular region with allowance for convective energy transfer in the liquid phase as well as temperature-dependent changes of viscosity. It is noted that the proposed method can be used to study steady-state problems of thermal convection in ingots obtained through continuous casting.

  9. Steel heat treating: mathematical modelling and numerical simulation of a problem arising in the automotive industry

    Directory of Open Access Journals (Sweden)

    Jose Manuel Diaz Moreno

    2017-12-01

    Full Text Available We describe a mathematical model for the industrial heating and cooling processes of a steel workpiece representing the steering rack of an automobile. The goal of steel heat treating is to provide a hardened surface on critical parts of the workpiece while keeping the rest soft and ductile in order to reduce fatigue. The high hardness is due to the phase transformation of steel accompanying the rapid cooling. This work takes into account both heating-cooling stage and viscoplastic model. Once the general mathematical formulation is derived, we can perform some numerical simulations.

  10. A new approach to the problem of dynamical quarks in numerical simulations of lattice QCD

    International Nuclear Information System (INIS)

    Luescher, M.

    1993-11-01

    Lattice QCD with an even number of degenerate quark flavours is shown to be a limit of a local bosonic field theory. The action of the bosonic theory is real and bounded from below so that standard simulation algorithms can be expected to apply. The feasibility of such calculations is discussed, but no practical tests have yet been made. (orig.)

  11. A numerical approach to weak Pareto solutions to equilibrium problems with equilibrium constraints

    Czech Academy of Sciences Publication Activity Database

    Červinka, Michal

    2006-01-01

    Roč. 57, č. 7 (2006), s. 14-17 ISSN 1335-3632. [ISCAM 2006. International Conference in Applied Mathematics for undergraduate and graduate students. Bratislava, 07.04.2006-08.04.2006] Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with complementarity constraints * multiobjective optimization * variational analysis Subject RIV: BD - Theory of Information

  12. Effects of Problem Decomposition (Partitioning) on the Rate of Convergence of Parallel Numerical Algorithms

    Czech Academy of Sciences Publication Activity Database

    Cullum, J. K.; Johnson, K.; Tůma, Miroslav

    2003-01-01

    Roč. 10, - (2003), s. 445-465 ISSN 1070-5325 R&D Projects: GA ČR GA201/02/0595; GA AV ČR IAA1030103 Institutional research plan: CEZ:AV0Z1030915 Keywords : parallel algorithms * graph partitioning * problem decomposition * rate of convergence Subject RIV: BA - General Mathematics Impact factor: 1.042, year: 2003

  13. The straightforward numerical treatment of the time dependent advection in air pollution problems and its verification

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichsen, K

    1982-01-01

    A very simple Lagrangian finite difference scheme has been developed to calculate the time dependent advection of air pollutants. It is mass conserving and avoids numerical pseudo-diffusion. No condition of numerical stability is required. The Eulerian grid used for the diffusion part of the pollutant transport equation remains unchanged. There are no restrictions on temporally and spatially variable emission rates, production and destruction processes, wind velocity, diffusion coefficients, roughness parameters or inversion heights. The only exception is that the wind field should not be too far from being homogeneous in the horizontal direction (test of D. W. Pepper and P. E. Long, 1978, J. appl. Met. 17, 228-233). Steady state solutions are nearly identical with corresponding analytical solutions. The propagation of a pollutant cloud is simulated more realistically as compared with the advection treatment of E. Runca and F. Sardei (1975, Atmospheric Environment 9, 69-80) and M. Dunst (1980, Z. Met. 30, 47-59). The course of a diffusion experiment is modelled to demonstrate the efficiency of the proposed method. Because of its simplicity, the method is especially suited for use in license processes, for control, and for calculating health risks in relation to industrial and power plant accidents with the goal of organizing efficient protection or evacuation.

  14. Numerical methods for limit problems in two-phase flow models

    International Nuclear Information System (INIS)

    Cordier, F.

    2011-01-01

    Numerical difficulties are encountered during the simulation of two-phase flows. Two issues are studied in this thesis: the simulation of phase transitions on one hand, and the simulation of both compressible and incompressible flows in the other hand. Un asymptotic study has shown that the loss of hyperbolicity of the bi fluid model was responsible for the difficulties encountered by the Roe scheme during the simulation of phase transitions. Robust and accurate polynomial schemes have thus been developed. To tackle the occasional lack of positivity of the solution, a numerical treatment based on adaptive diffusion was proposed and allowed to simulate with accuracy the test-cases of a boiling channel with creation of vapor and a tee-junction with separation of the phases. In a second part, an all-speed scheme for compressible and incompressible flows have been proposed. This pressure-based semi-implicit asymptotic preserving scheme is conservative, solves an elliptic equation on the pressure, and has been designed for general equations of state. The scheme was first developed for the full Euler equations and then extended to the Navier-Stokes equations. The good behaviour of the scheme in both compressible and incompressible regimes have been investigated. An extension of the scheme to the two-phase mixture model was implemented and demonstrated the ability of the scheme to simulate two-phase flows with phase change and a water-steam equation of state. (author) [fr

  15. The intergenerational transmission of at-risk/problem gambling: The moderating role of parenting practices.

    Science.gov (United States)

    Dowling, Nicki A; Shandley, Kerrie A; Oldenhof, Erin; Affleck, Julia M; Youssef, George J; Frydenberg, Erica; Thomas, Shane A; Jackson, Alun C

    2017-10-01

    Although parenting practices are articulated as underlying mechanisms or protective factors in several theoretical models, their role in the intergenerational transmission of gambling problems has received limited research attention. This study therefore examined the degree to which parenting practices (positive parenting, parental involvement, and inconsistent discipline) moderated the intergenerational transmission of paternal and maternal problem gambling. Students aged 12-18 years (N = 612) recruited from 17 Australian secondary schools completed a survey measuring parental problem gambling, problem gambling severity, and parenting practices. Participants endorsing paternal problem gambling (23.3%) were 4.3 times more likely to be classified as at-risk/problem gamblers than their peers (5.4%). Participants endorsing maternal problem gambling (6.9%) were no more likely than their peers (4.0%) to be classified as at-risk/problem gamblers. Paternal problem gambling was a significant predictor of offspring at-risk/problem gambling after controlling for maternal problem gambling and participant demographic characteristics. The relationship between maternal problem gambling and offspring at-risk/problem gambling was buffered by parental involvement. Paternal problem gambling may be important in the development of adolescent at-risk/problem gambling behaviours and higher levels of parental involvement buffers the influence of maternal problem gambling in the development of offspring gambling problems. Further research is therefore required to identify factors that attenuate the seemingly greater risk of transmission associated with paternal gambling problems. Parental involvement is a potential candidate for prevention and intervention efforts designed to reduce the intergenerational transmission of gambling problems. (Am J Addict 2017;26:707-712). © 2017 American Academy of Addiction Psychiatry.

  16. [Interdisciplinarity in gerontology: Theoretical problems and practical challenges].

    Science.gov (United States)

    Brandenburg, H

    2015-04-01

    Philosophy of science is the theoretical background of this article. Firstly, a definition of interdisciplinarity is given, integrating experiences from longitudinal studies in gerontology and arguing for rejecting the large vocable "interdisciplinarity", because of its overloaded meaning. Secondly, science-oriented, sociopsychological and practical barriers of interdisciplinary work in gerontology are presented, whereby the central statement is that interdisciplinarity is preconditionally dependent on a "culture of understanding". Thirdly, a model of interdisciplinarity in gerontology is shown. In general, this article does not focus on the question whether gerontology is a multidisciplinary, interdisciplinary or transdisciplinary discipline but how the requirement of interdisciplinarity can be successfully implemented. In conclusion, interdisciplinarity is not established due to the subject (of aging) or a methodological approach but evolves based on reciprocal contact between different disciplines, which can be entitled "fair cooperation."

  17. Problems and their solutions in practical application of Eurocodes in seismic design of RC structures

    Directory of Open Access Journals (Sweden)

    Milev Jordan

    2016-01-01

    Full Text Available The main purpose of the paper is to present practical application of Eurocodes in the field of RC structures design. The selected examples represent the main problems in practical application of Eurocodes for seismic analysis and design of RC Structures in Bulgarian construction practice. The analysis is focused on some structural and economic problems as well as on some contradictions in Eurocode 8 itself. Special attention is paid to the practical solution of the following problems: recognition of torsionally flexible systems, stiffness reduction of RC elements for linear analysis dimensions and detailing of confined boundary areas of shear walls, detailing of wall structures, etc. Those problems appear during the practical design of some buildings in Bulgaria. Several proposals for solving some problems defined in the paper are presented through some practical examples. Some conclusions are made for further application of Eurocode 8 in the design and construction practice. The importance of some rules and procedures in Eurocode 8 is supported by the examples of damaged RC members during the past earthquakes. The problems of Eurocode 8 and their solutions are illustrated through the experience of Bulgarian construction practice.

  18. Problem based teaching in indoor Air Science and Practice

    DEFF Research Database (Denmark)

    Kjærgaard, Søren K.

    1999-01-01

    on the experiment was that the method was useful even in a very mixed group, and highly motivating for the teachers. Similarly, at the MPH-school at Aarhus University, the method has given good experiences in a multidisciplinary group of mature students. Their task have been to evaluate health problems during......This paper discuss experiences with problembased training by a group under the EU-funded ERASMUS program, and experiences at the MPH-program at Aarhus University in Denmark as well as it gives views on the structure and content of a possible common core curriculum, students etc. Problembased...... training has been applied for long time at Limburg University in Maastricht, The Netherlands. Under the European student exchange (ERASMUS) program an international group of teachers joined to teach a crew of international student group (postgraduates) in Brussels in a week using problembased teaching...

  19. EMOTIONAL MATURITY OF PERSONALITY: THE PRACTICAL PROBLEM OF PSYCHOLOGICAL DIAGNOSIS

    Directory of Open Access Journals (Sweden)

    O. I. Afonina

    2013-03-01

    Full Text Available In the dif?cult conditions of the contemporary society which are far from being favorable to maintain one’s emotional and physical health the problem of development and achievement of emotional maturity as a factor of the well-being is getting more signi?cant. Based on the theoretical concepts of different scientists who de?ned the construct of emotional maturity three groups of psychological methods for assessing emotional maturity are analyzed. The ?rst group includes the methods that are used to assess emotional maturity explicitly and have a theoretical or empirical veri?cation. The second group includes the methods that are intended to assess emotional maturity as a separate scale complimented by other scales, related to evaluating other aspects of emotionality in  the  structure  of  the  personality.  The  third  group  includes  the  methods  in  which  emotional maturity is mentioned in the description of other psychic phenomena, or in the interpretation of certain factors (scales. Psychodiagnostic methods studying different parameters depending on the theoretical concepts of the authors about the structure and content of the emotional maturity of the personality make references to concepts of emotional development, consciousness, cognitive and volitional capacities of the personality and the coping strategies the individual prefer to use. The problem of developing valid and reliable psychodiagnostic methods of studying emotional maturity of the adult personality as a holistic phenomenon still awaits attention and retains its signi?cance.

  20. Mathematical and numerical study of nonlinear boundary problems related to plasma physics

    International Nuclear Information System (INIS)

    Sermange, M.

    1982-06-01

    After the study of some equations based on the Hodgkin-Huxley model, the work presented here is concerned with nonlinear boundary problems in MHD. They are gathered in two subjects: equilibrium equations and stability equations. The axisymmetric MHD equilibrium equations with free boundary have been studied by different authors, particularly the existence, regularity, unicity and non-unicity. Here, bifurcation, convergence of calculation methods existence of solutions in a discontinuous frame are studied. MHD stability can be determined by the principle of Bernstein et al; the mathematical work concerned here bears on the equivalence, in the case of two-dimensional or axisymmetric stability, between this model and a scalar eigenvalue problem which is introduced. At last, modules for computing MHD equilibrium for the simulation of plasma confinement in a tokamak are described [fr

  1. Novel Numerical Methods for Optimal Control Problems Involving Fractional-Order Differential Equations

    Science.gov (United States)

    2018-03-14

    UNIVERSITY OF TECHNOLOGY Final Report 03/14/2018 DISTRIBUTION A: Distribution approved for public release. AF Office Of Scientific Research (AFOSR...optimal control problems involving fractional-order differential equations Wang, Song Curtin University of Technology Kent Street, Bentley WA6102...Article history : Received 3 October 2016 Accepted 26 March 2017 Available online 29 April 2017 Keywords: Hamilton–Jacobi–Bellman equation Financial

  2. Coarse-convex-compactification approach to numerical solution of nonconvex variational problems

    Czech Academy of Sciences Publication Activity Database

    Meziat, R.; Roubíček, Tomáš; Patino, D.

    2010-01-01

    Roč. 31, č. 4 (2010), s. 460-488 ISSN 0163-0563 Grant - others:GA MŠk(CZ) LC06052 Program:LC Institutional research plan: CEZ:AV0Z20760514 Keywords : convex approximations * method of moments * relaxed variational problems Subject RIV: BA - General Mathematics Impact factor: 0.687, year: 2010 http://www.informaworld.com/smpp/content~db=all~content=a922886514~frm=titlelink

  3. An accurate model for numerical prediction of piezoelectric energy harvesting from fluid structure interaction problems

    International Nuclear Information System (INIS)

    Amini, Y; Emdad, H; Farid, M

    2014-01-01

    Piezoelectric energy harvesting (PEH) from ambient energy sources, particularly vibrations, has attracted considerable interest throughout the last decade. Since fluid flow has a high energy density, it is one of the best candidates for PEH. Indeed, a piezoelectric energy harvesting process from the fluid flow takes the form of natural three-way coupling of the turbulent fluid flow, the electromechanical effect of the piezoelectric material and the electrical circuit. There are some experimental and numerical studies about piezoelectric energy harvesting from fluid flow in literatures. Nevertheless, accurate modeling for predicting characteristics of this three-way coupling has not yet been developed. In the present study, accurate modeling for this triple coupling is developed and validated by experimental results. A new code based on this modeling in an openFOAM platform is developed. (paper)

  4. Solved problems in classical mechanics analytical and numerical solutions with comments

    CERN Document Server

    de Lange, O L

    2010-01-01

    Apart from an introductory chapter giving a brief summary of Newtonian and Lagrangian mechanics, this book consists entirely of questions and solutions on topics in classical mechanics that will be encountered in undergraduate and graduate courses. These include one-, two-, and three- dimensional motion; linear and nonlinear oscillations; energy, potentials, momentum, and angular momentum; spherically symmetric potentials; multi-particle systems; rigid bodies; translation androtation of the reference frame; the relativity principle and some of its consequences. The solutions are followed by a set of comments intended to stimulate inductive reasoning and provide additional information of interest. Both analytical and numerical (computer) techniques are used to obtain andanalyze solutions. The computer calculations use Mathematica (version 7), and the relevant code is given in the text. It includes use of the interactive Manipulate function which enables one to observe simulated motion on a computer screen, and...

  5. A numerical approach of thermal problems coupling fluid solid and radiation in complex geometries; Approche numerique de problemes thermiques couplant fluides, solides et rayonnement en geometries complexes

    Energy Technology Data Exchange (ETDEWEB)

    Peniguel, C; Rupp, I

    1995-11-01

    In many industrial problems, heat transfer does play an important part. Quite often, radiation, convection and radiation are present simultaneously. This paper presents the numerical tool handling simultaneously these phenomena. Fluid is tackled by the finite element code N3S, radiation (restricted to a non participating medium) and conduction are handled with SYRTHES respectively by a radiosity method and a finite element method. The main originality of the product is that meshes used to solve each phenomenon are completely independent. This allows users to choose the most appropriate spatial discretization for each part or phenomenon. This flexibility requires of course robust and fast data exchange procedures (temperature, convective flux, radiative flux) between the independent grids. This operation is done automatically by the code SYRTHES. One simple problem illustrating the interest of this development is presented at the end of the paper. (author). 6 refs., 8 figs.

  6. Numerical analysis of impact-penetration problems for nuclear reactor safety

    International Nuclear Information System (INIS)

    Dubois, J.J.; Chedmail, J.F.; Bianchini, J.C.

    1977-01-01

    This paper discusses the finite element and finite difference analysis of two impact penetration problems, namely a fuel cask drop on a foundation slab and a missile penetration into a reinforced concrete structure. For a realistic detailed analysis, advanced techniques were required in the following areas: reinforced concrete simulation; remeshing algorithms for penetration induced distortions; boundary condition. The fuel cask drop on a concrete slab generates complex elasto plastic waves which propagate towards the pool where tensile cracks might appear. The problem is analysed in two steps: calculation of the energy absorbed locally around the impacted area; calculation of the three dimensional wave propagation towards the pool. For the analysis of missile penetration problems, two examples are shown: a 3000 kg missile with a velocity of 132 m/s penetrates a 1.2 m thick concrete wall (PAM-GDYNS) and a 3600 kg missile with a velocity of 90 m/s (F.D. Program HEMP-ESI) penetrates a wall at a floor level. For the second case, the computed impact-penetration mechanism is

  7. Practical problems of groundwater model ages for groundwater protection studies

    International Nuclear Information System (INIS)

    Matthess, G.; Muennich, K.O.; Sonntag, C.

    1976-01-01

    Water authorities in the Federal Republic of Germany have established a system of protection zones for the protection of groundwater supplies from pollution. One zone (Zone II) is defined by an outer boundary from which the groundwater needs 50 days to flow to the well. 50 days is the period accepted for the elimination of pathogenic germs. However, within Zone II carbon-14 measurements of water may give model ages of several thousand years, which may lead to some confusion in the legal and practical aspects of this scheme. These model ages may result from uncertainties in the chemical model, or from mixing of waters of different ages, either within the aquifer or during extraction at the well. The paper discusses scientific aspects of the establishment of protection zones. Two processes affecting the model age determinations are examined in detail. First, the mechanism of diffusion transport downwards through porous, but impermeable, aquicludes is examined for stable trace substances and radioactive isotopes. Secondly, examples are given of model ages resulting from mixtures of new and old waters. It is recommended that such model ages should not be reported as 'ages' since they may be misinterpreted in groundwater protection applications. (author)

  8. Corruption as a Problem of Political Theory and Political Practice

    Directory of Open Access Journals (Sweden)

    Anna V. Shashkova

    2015-01-01

    Full Text Available The present article is dedicated to the analysis of "corruption" from point of view of political practice and political theory. The present article studies historical examples of corruption: corruption during the era of Alexander the Great, Carthage, Roman Republic. The article gives the evolution of the term "corruption", pointing out current aspects of the term. The article provides positive and negative results of corruption, gives resume. The present article analyses corruption results: economical, political and social. Most important economical consequences of corruption are the following: increase of shadow economy, decrease of tax payments, weakening of the state budget, breach of market competition, decrease of market effectiveness, destabilization of the idea of market economy. Most important social consequences of corruption are the following: great distinction between the declared and real values, which creates a "double standard" of the moral and behavior, distraction of great sums from public and humanitarian development, increase of property disproportion, increase of social tension. The present article names most important political consequences of corruption: shift of ideas from public development to the security of power of oligarchy, decrease of trust to the state, decrease of image of the country at the international arena, increase of its economical and political isolation, decrease of political competition. The present article gives one of the resumes that the globalization process increases corruption. Together with globalization most important role is given to corporations and corporate corruption comes to the front raw.

  9. Multiconfiguration time-dependent self-consistent field approximations in the numerical solution of quantum dynamical problems

    International Nuclear Information System (INIS)

    Kotler, Z.; Neria, E.; Nitzan, A.

    1991-01-01

    The use of the time-dependent self-consistent field approximation (TDSCF) in the numerical solution of quantum curve crossing and tunneling dynamical problems is investigated. Particular emphasis is given to multiconfiguration TDSCF (MCTDSCF) approximations, which are shown to perform considerably better with only a small increase in computational effort. We investigate a number of simple models in which a 'system' characterized by two electronic potential surfaces evolves while interacting with a 'bath' mode described by an harmonic oscillator, and compare exact numerical solutions to one- and two-configuration TDSCF approximations. We also introduce and investigate a semiclassical approximation in which the 'bath' mode is described by semiclassical wavepackets (one for each electronic state) and show that for all models investigated this scheme works very well in comparison with the fully quantum MCTDSCF approximation. This provides a potentially very useful method to simulate strongly quantum systems coupled to an essentially classical environment. (orig.)

  10. Nature Inspired Computational Technique for the Numerical Solution of Nonlinear Singular Boundary Value Problems Arising in Physiology

    Directory of Open Access Journals (Sweden)

    Suheel Abdullah Malik

    2014-01-01

    Full Text Available We present a hybrid heuristic computing method for the numerical solution of nonlinear singular boundary value problems arising in physiology. The approximate solution is deduced as a linear combination of some log sigmoid basis functions. A fitness function representing the sum of the mean square error of the given nonlinear ordinary differential equation (ODE and its boundary conditions is formulated. The optimization of the unknown adjustable parameters contained in the fitness function is performed by the hybrid heuristic computation algorithm based on genetic algorithm (GA, interior point algorithm (IPA, and active set algorithm (ASA. The efficiency and the viability of the proposed method are confirmed by solving three examples from physiology. The obtained approximate solutions are found in excellent agreement with the exact solutions as well as some conventional numerical solutions.

  11. On a free-surface problem with moving contact line: From variational principles to stable numerical approximations

    Science.gov (United States)

    Fumagalli, Ivan; Parolini, Nicola; Verani, Marco

    2018-02-01

    We analyze a free-surface problem described by time-dependent Navier-Stokes equations. Surface tension, capillary effects and wall friction are taken into account in the evolution of the system, influencing the motion of the contact line - where the free surface hits the wall - and of the dynamics of the contact angle. The differential equations governing the phenomenon are first derived from the variational principle of minimum reduced dissipation, and then discretized by means of the ALE approach. The numerical properties of the resulting scheme are investigated, drawing a parallel with the physical properties holding at the continuous level. Some instability issues are addressed in detail, in the case of an explicit treatment of the geometry, and novel additional terms are introduced in the discrete formulation in order to damp the instabilities. Numerical tests assess the suitability of the approach, the influence of the parameters, and the effectiveness of the new stabilizing terms.

  12. Singular boundary value problem for the integrodifferential equation in an insurance model with stochastic premiums: Analysis and numerical solution

    Science.gov (United States)

    Belkina, T. A.; Konyukhova, N. B.; Kurochkin, S. V.

    2012-10-01

    A singular boundary value problem for a second-order linear integrodifferential equation with Volterra and non-Volterra integral operators is formulated and analyzed. The equation is defined on ℝ+, has a weak singularity at zero and a strong singularity at infinity, and depends on several positive parameters. Under natural constraints on the coefficients of the equation, existence and uniqueness theorems for this problem with given limit boundary conditions at singular points are proved, asymptotic representations of the solution are given, and an algorithm for its numerical determination is described. Numerical computations are performed and their interpretation is given. The problem arises in the study of the survival probability of an insurance company over infinite time (as a function of its initial surplus) in a dynamic insurance model that is a modification of the classical Cramer-Lundberg model with a stochastic process rate of premium under a certain investment strategy in the financial market. A comparative analysis of the results with those produced by the model with deterministic premiums is given.

  13. The practical and principled problems with educational neuroscience.

    Science.gov (United States)

    Bowers, Jeffrey S

    2016-10-01

    The core claim of educational neuroscience is that neuroscience can improve teaching in the classroom. Many strong claims are made about the successes and the promise of this new discipline. By contrast, I show that there are no current examples of neuroscience motivating new and effective teaching methods, and argue that neuroscience is unlikely to improve teaching in the future. The reasons are twofold. First, in practice, it is easier to characterize the cognitive capacities of children on the basis of behavioral measures than on the basis of brain measures. As a consequence, neuroscience rarely offers insights into instruction above and beyond psychology. Second, in principle, the theoretical motivations underpinning educational neuroscience are misguided, and this makes it difficult to design or assess new teaching methods on the basis of neuroscience. Regarding the design of instruction, it is widely assumed that remedial instruction should target the underlying deficits associated with learning disorders, and neuroscience is used to characterize the deficit. However, the most effective forms of instruction may often rely on developing compensatory (nonimpaired) skills. Neuroscience cannot determine whether instruction should target impaired or nonimpaired skills. More importantly, regarding the assessment of instruction, the only relevant issue is whether the child learns, as reflected in behavior. Evidence that the brain changed in response to instruction is irrelevant. At the same time, an important goal for neuroscience is to characterize how the brain changes in response to learning, and this includes learning in the classroom. Neuroscientists cannot help educators, but educators can help neuroscientists. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  14. FASTREACT – An efficient numerical framework for the solution of reactive transport problems

    International Nuclear Information System (INIS)

    Trinchero, Paolo; Molinero, Jorge; Román-Ross, Gabriela; Berglund, Sten; Selroos, Jan-Olof

    2014-01-01

    Highlights: • We present a tool for the efficient solution of reactive transport problems. • The tool is used to simulate radionuclide transport in a two-dimensional medium. • The results are successfully compared with those obtained using an Eulerian approach. • A large-scale application example is also solved. • The results show that the proposed tool can efficiently solve large-scale models. - Abstract: In the framework of safety assessment studies for geological disposal, large scale reactive transport models are powerful inter-disciplinary tools aiming at supporting regulatory decision making as well as providing input to repository engineering activities. Important aspects of these kinds of models are their often very large temporal and spatial modelling scales and the need to integrate different non-linear processes (e.g., mineral dissolution and precipitation, adsorption and desorption, microbial reactions and redox transformations). It turns out that these types of models may be computationally highly demanding. In this work, we present a Lagrangian-based framework, denoted as FASTREACT, that aims at solving multi-component-reactive transport problems with a computationally efficient approach allowing complex modelling problems to be solved in large spatial and temporal scales. The tool has been applied to simulate radionuclide migration in a synthetic heterogeneous transmissivity field and the results have been successfully compared with those obtained using a standard Eulerian approach. Finally, the same geochemical model has been coupled to an ensemble of realistic three-dimensional transport pathways to simulate the migration of a set of radionuclides from a hypothetical repository for spent nuclear fuel to the surface. The results of this modelling exercise, which includes key processes such as the exchange of mass between the conductive fractures and the matrix, show that FASTREACT can efficiently solve large-scale reactive transport models

  15. Discretization and Numerical Solution of a Plane Problem in the Mechanics of Interfacial Cracks

    Science.gov (United States)

    Khoroshun, L. P.

    2017-01-01

    The Fourier transform is used to reduce the linear plane problem of the tension of a body with an interfacial crack to a system of dual equations for the transformed stresses and, then, to a system of integro-differential equations for the difference of displacements of the crack faces. After discretization, this latter system transforms into a system of algebraic equations for displacements of the crack faces. The effect of the bielastic constant and the number of discretization points on the half-length of the crack faces and the distribution of stresses at the interface is studied

  16. The numerical analysis of eigenvalue problem solutions in the multigroup diffusion theory

    International Nuclear Information System (INIS)

    Woznick, Z.I.

    1994-01-01

    In this paper a general iteration strategy for solving the discrete form of multidimensional neutron diffusion equations is described. Usually the solution method is based on the system of inner and outer iterations. The presented matrix formalism allows us to visualize clearly, how the used matrix splitting influences the structure of the matrix in an eigenvalue problem to be solved as well as the independence between inner and outer iterations within global iterations. To keep the page limit, the present version of the paper consists only with first three of five sections given in the original paper under the same title (which will be published soon). (author). 13 refs

  17. Parallel Implementation of Numerical Solution of Few-Body Problem Using Feynman’s Continual Integrals

    Directory of Open Access Journals (Sweden)

    Naumenko Mikhail

    2018-01-01

    Full Text Available Modern parallel computing algorithm has been applied to the solution of the few-body problem. The approach is based on Feynman’s continual integrals method implemented in C++ programming language using NVIDIA CUDA technology. A wide range of 3-body and 4-body bound systems has been considered including nuclei described as consisting of protons and neutrons (e.g., 3,4He and nuclei described as consisting of clusters and nucleons (e.g., 6He. The correctness of the results was checked by the comparison with the exactly solvable 4-body oscillatory system and experimental data.

  18. Parallel Implementation of Numerical Solution of Few-Body Problem Using Feynman's Continual Integrals

    Science.gov (United States)

    Naumenko, Mikhail; Samarin, Viacheslav

    2018-02-01

    Modern parallel computing algorithm has been applied to the solution of the few-body problem. The approach is based on Feynman's continual integrals method implemented in C++ programming language using NVIDIA CUDA technology. A wide range of 3-body and 4-body bound systems has been considered including nuclei described as consisting of protons and neutrons (e.g., 3,4He) and nuclei described as consisting of clusters and nucleons (e.g., 6He). The correctness of the results was checked by the comparison with the exactly solvable 4-body oscillatory system and experimental data.

  19. A numerical solution to an inverse unsteady-state heat transfer problem involving the Trefftz functions

    Directory of Open Access Journals (Sweden)

    Maciejewska Beata

    2017-01-01

    Full Text Available This paper shows the results concerning flow boiling heat transfer in an asymmetrically heated vertical minichannel. The heated element for FC-72 Fluorinert flowing in that minichannel was a thin foil. The foil surface temperature was monitored continuously at 18 points by K-type thermocouples from the outer foil surface. Fluid temperature and pressure in the minichannel inlet and outlet, current supplied to the foil and voltage drop were also monitored. Measurements were carried out at 1 s intervals. The objective was to determine the heat transfer coefficient on the heated foil–fluid contact surface in the minichannel. It was obtained from the Robin boundary condition. The foil temperature was the result of solving the nonstationary two-dimensional inverse boundary problem in the heated foil. Using the FEM combined with Trefftz functions as basis functions solved the problem. The unknown temperature values at nodes were calculated by minimising the adequate functional. The values of local heat transfer coefficients were consistent with the results obtained by the authors in their previous studies when steady-state conditions were analysed. This time, however, these values were analysed as time dependent, which facilitated observation of coefficient changes that were impossible to observe under the steady-state conditions.

  20. Precise numerical results for limit cycles in the quantum three-body problem

    International Nuclear Information System (INIS)

    Mohr, R.F.; Furnstahl, R.J.; Hammer, H.-W.; Perry, R.J.; Wilson, K.G.

    2006-01-01

    The study of the three-body problem with short-range attractive two-body forces has a rich history going back to the 1930s. Recent applications of effective field theory methods to atomic and nuclear physics have produced a much improved understanding of this problem, and we elucidate some of the issues using renormalization group ideas applied to precise nonperturbative calculations. These calculations provide 11-12 digits of precision for the binding energies in the infinite cutoff limit. The method starts with this limit as an approximation to an effective theory and allows cutoff dependence to be systematically computed as an expansion in powers of inverse cutoffs and logarithms of the cutoff. Renormalization of three-body bound states requires a short range three-body interaction, with a coupling that is governed by a precisely mapped limit cycle of the renormalization group. Additional three-body irrelevant interactions must be determined to control subleading dependence on the cutoff and this control is essential for an effective field theory since the continuum limit is not likely to match physical systems (e.g., few-nucleon bound and scattering states at low energy). Leading order calculations precise to 11-12 digits allow clear identification of subleading corrections, but these corrections have not been computed

  1. A numerical solution of the problem of crown forest fire initiation and spread

    Science.gov (United States)

    Marzaeva, S. I.; Galtseva, O. V.

    2018-05-01

    Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. The study takes in to account the mutual interaction of the forest fires and three-dimensional atmosphere flows. The research is done by means of mathematical modeling of physical processes. It is based on numerical solution of Reynolds equations for chemical components and equations of energy conservation for gaseous and condensed phases. It is assumed that the forest during a forest fire can be modeled as a two-temperature multiphase non-deformable porous reactive medium. A discrete analog for the system of equations was obtained by means of the control volume method. The developed model of forest fire initiation and spreading would make it possible to obtain a detailed picture of the variation in the velocity, temperature and chemical species concentration fields with time. Mathematical model and the result of the calculation give an opportunity to evaluate critical conditions of the forest fire initiation and spread which allows applying the given model for of means for preventing fires.

  2. Asymptotic solutions of numerical transport problems in optically thick, diffusive regimes

    International Nuclear Information System (INIS)

    Larsen, E.W.; Morel, J.E.; Miller, W.F. Jr.

    1987-01-01

    We present an asymptotic analysis of spatial differencing schemes for the discrete-ordinates equations, for diffusive media with spatial cells that are not optically thin. Our theoretical tool is an asymptotic expansion that has previously been used to describe the transform from analytic transport to analytic diffusion theory for such media. To introduce this expansion and its physical rationale, we first describe it for the analytic discrete-ordinates equations. Then, we apply the expansion to the spatially discretized discrete-ordinates equations, with the spatial mesh scaled in either of two physically relevant ways such that the optical thickness of the spatial cells is not small. If the result of either expansion is a legitimate diffusion description for either the cell-averaged or cell-edge fluxes, then we say that the approximate flux has the appropriate diffusion limit; otherwise, we say it does not. We consider several transport differencing schemes that are applicable in neutron transport and thermal radiation applications. We also include numerical results which demonstrate the validity of our theory and show that differencing schemes that do have a particular diffusion limit are substantially more accurate, in the regime described by the limit, than those that do not. copyright 1987 Academic Press, Inc

  3. Validations of BWR nuclear design code using ABWR MOX numerical benchmark problems

    International Nuclear Information System (INIS)

    Takano, Shou; Sasagawa, Masaru; Yamana, Teppei; Ikehara, Tadashi; Yanagisawa, Naoki

    2017-01-01

    BWR core design code package (the HINES assembly code and the PANACH core simulator), being used for full MOX-ABWR core design, has been benchmarked against the high-fidelity numerical solutions as references, for the purpose of validating its capability of predicting the BWR core design parameters systematically from UO 2 to 100% MOX cores. The reference solutions were created by whole core critical calculations using MCNPs with the precisely modeled ABWR cores both in hot and cold conditions at BOC and EOC of the equilibrium cycle. A Doppler-Broadening Rejection Correction (DCRB) implemented MCNP5-1.4 with ENDF/B-VII.0 was mainly used to evaluate the core design parameters, except for effective delayed neutron fraction (β eff ) and prompt neutron lifetime (l) with MCNP6.1. The discrepancies in the results between the design codes HINES-PANACH and MCNPs for the core design parameters such as the bundle powers, hot pin powers, control rod worth, boron worth, void reactivity, Doppler reactivity, β eff and l, are almost within target accuracy, leading to the conclusion that HINES-PANACH has sufficient fidelity for application to full MOX-ABWR core design. (author)

  4. Numerical modeling for hydro-mechanical coupled problems in the context of geo-materials

    International Nuclear Information System (INIS)

    Fernandes, R.

    2009-01-01

    The main technical purpose of this PhD Thesis is to build up and validate a regularisation method, able to remedy to the spurious mesh dependency of post localized computations, in order to make possible hydro-mechanical coupling studies for geo-materials. The proposed model is based on the framework of second gradient models and is called the micro-dilation model. It allows to predict robustly the hydro-mechanical coupled behaviors related to the degradation of natural soils and rocks. This modeling is a clear enhancement with respect to classical second gradient computations since it requires less degrees of freedom and consequently is less time consuming. Its efficiency is shown through hydro-mechanical coupled simulations of underground excavations. Finally, an algorithm to detect several solutions in the direction of singular modes associated with negative eigenvalues is presented. It allows us to deal with the non-linear nature of the irreversible behavior of soils and rocks. The scope of this bifurcation analysis is restricted to symmetrical operators. Through the simulations of homogeneous biaxial tests and underground excavations under drained conditions, it is shown that this algorithm is an efficient and robust tool not only to detect several solutions but also to overcome numerical instabilities near singular points or due to snap-back. (author)

  5. Judicial protection of pension rights: problems of theory and practice

    Directory of Open Access Journals (Sweden)

    Marina G. Sedelnikova

    2018-01-01

    Full Text Available The subject. The article is devoted to analysis of pension disputes resolution in courts.The purpose of the article is to reveal trends of pension disputes resolution and identify the ways of increasing the efficiency of judicial protection of citizens’ pension rights.The methodology. Both general scientific methods (analysis, synthesis, description and special scientific methods (formal-legal methods method of legal interpretation were used.Results, scope of application. Pension legislation still does not contain a legal definition of the term “pension dispute” despite currently the prevalence of this category of cases; the legal science still has not developed a uniform approach to definition of the essence of the pension dispute.Special attention is paid to the issues of definition of the facts in proof, that is complicated because of instability of the pension legislation and a large amount of normative array. Special rules relating to the admissibility of evidence are divided from legally significant circumstances. The attention is focused on the most problematic points that arise in the process of proving: the procedure for confirmation of experience, employment in certain types of work quotas.Recommendations aimed at improving the effectiveness of judicial protection of the pension rights of citizens are formulated on the basis on the analysis of the identified problems that arise during consideration of pension disputes by law enforcement authorities. Recommendations include the need to improve the quality of normative legal acts, systematization of the pension legislation, increasing demands for training of judges, the creation of conditions conducive to the judges’ specialization. The necessity of increase activities of the Supreme Court in the process of issuing clarifications on issues arising in the application of the pension legislation is also considered.Conclusions. The existence of a number of features of the substantive

  6. On the solution of two-point linear differential eigenvalue problems. [numerical technique with application to Orr-Sommerfeld equation

    Science.gov (United States)

    Antar, B. N.

    1976-01-01

    A numerical technique is presented for locating the eigenvalues of two point linear differential eigenvalue problems. The technique is designed to search for complex eigenvalues belonging to complex operators. With this method, any domain of the complex eigenvalue plane could be scanned and the eigenvalues within it, if any, located. For an application of the method, the eigenvalues of the Orr-Sommerfeld equation of the plane Poiseuille flow are determined within a specified portion of the c-plane. The eigenvalues for alpha = 1 and R = 10,000 are tabulated and compared for accuracy with existing solutions.

  7. Numerical analysis of the asymptotic behavior of solutions of a boundary problem for a nonlinear parabolic equation

    International Nuclear Information System (INIS)

    Vasileva, D.P.

    1993-01-01

    Blow-up and global time self-similar solutions of a boundary problem for a nonlinear equation u t = Δ u σ+1 + u β are found in the case β = σ + 1. It is shown that they describe the asymptotic behavior of a wide class of initial perturbations. A numerical investigation of the solutions in the case β>σ + 1 is also made. A hypothesis is done that the behavior for large times of global time solutions is described by the self-similar solutions of the equation without source.(author). 20 refs.; 9 figs

  8. Account of volume heat capacity on interface in numerical solution of the Stephen problem using the strained coordinates method

    International Nuclear Information System (INIS)

    Latynin, V.A.; Reshetov, V.A.; Karaseva, L.N.

    1988-01-01

    Numerical solution of the Stephen problem by the strained coordinate method is presented for an one-dimensional sphere. Differential formulae of heat fluxes from moving interfaces do not take into account volume heat capacities of the front nodes. Calculations, carried out according to these balanced formulae, as well as according to those usually used, have shown that the balanced formulae permit to reduce approximately by an order the number of nodes on the sphere radius, if similar accuracy of heat balance of the whole process of melting or crystallization is observed. 2 refs.; 1 fig

  9. MATHEMATICAL MODELING AND NUMERICAL SOLUTION OF IRON CORROSION PROBLEM BASED ON CONDENSATION CHEMICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Basuki Widodo

    2012-02-01

    Full Text Available Corrosion process is a natural case that happened at the various metals, where the corrosion process in electrochemical can be explained by using galvanic cell. The iron corrosion process is based on the acidity degree (pH of a condensation, iron concentration and condensation temperature of electrolyte. Those are applied at electrochemistry cell. The iron corrosion process at this electrochemical cell also able to generate electrical potential and electric current during the process takes place. This paper considers how to build a mathematical model of iron corrosion, electrical potential and electric current. The mathematical model further is solved using the finite element method. This iron corrosion model is built based on the iron concentration, condensation temperature, and iteration time applied. In the electric current density model, the current based on electric current that is happened at cathode and anode pole and the iteration time applied. Whereas on the potential  electric model, it is based on the beginning of electric potential and the iteration time applied. The numerical results show that the part of iron metal, that is gristle caused by corrosion, is the part of metal that has function as anode and it has some influences, such as time depth difference, iron concentration and condensation temperature on the iron corrosion process and the sum of reduced mass during corrosion process. Moreover, difference influence of time and beginning electric potential has an effect on the electric potential, which emerges during corrosion process at the electrochemical cell. Whereas, at the electrical current is also influenced by difference of depth time and condensation temperature applied.Keywords: Iron Corrosion, Concentration of iron, Electrochemical Cell and Finite Element Method

  10. Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem

    KAUST Repository

    Nick, H.M.

    2013-02-01

    The reactive mixing between seawater and terrestrial water in coastal aquifers influences the water quality of submarine groundwater discharge. While these waters come into contact at the seawater groundwater interface by density driven flow, their chemical components dilute and react through dispersion. A larger interface and wider mixing zone may provide favorable conditions for the natural attenuation of contaminant plumes. It has been claimed that the extent of this mixing is controlled by both, porous media properties and flow conditions. In this study, the interplay between dispersion and reactive processes in coastal aquifers is investigated by means of numerical experiments. Particularly, the impact of dispersion coefficients, the velocity field induced by density driven flow and chemical component reactivities on reactive transport in such aquifers is studied. To do this, a hybrid finite-element finite-volume method and a reactive simulator are coupled, and model accuracy and applicability are assessed. A simple redox reaction is considered to describe the degradation of a contaminant which requires mixing of the contaminated groundwater and the seawater containing the terminal electron acceptor. The resulting degradation is observed for different scenarios considering different magnitudes of dispersion and chemical reactivity. Three reactive transport regimes are found: reaction controlled, reaction-dispersion controlled and dispersion controlled. Computational results suggest that the chemical components\\' reactivity as well as dispersion coefficients play a significant role on controlling reactive mixing zones and extent of contaminant removal in coastal aquifers. Further, our results confirm that the dilution index is a better alternative to the second central spatial moment of a plume to describe the mixing of reactive solutes in coastal aquifers. © 2012 Elsevier B.V.

  11. Numeric treatment of nonlinear second order multi-point boundary value problems using ANN, GAs and sequential quadratic programming technique

    Directory of Open Access Journals (Sweden)

    Zulqurnain Sabir

    2014-06-01

    Full Text Available In this paper, computational intelligence technique are presented for solving multi-point nonlinear boundary value problems based on artificial neural networks, evolutionary computing approach, and active-set technique. The neural network is to provide convenient methods for obtaining useful model based on unsupervised error for the differential equations. The motivation for presenting this work comes actually from the aim of introducing a reliable framework that combines the powerful features of ANN optimized with soft computing frameworks to cope with such challenging system. The applicability and reliability of such methods have been monitored thoroughly for various boundary value problems arises in science, engineering and biotechnology as well. Comprehensive numerical experimentations have been performed to validate the accuracy, convergence, and robustness of the designed scheme. Comparative studies have also been made with available standard solution to analyze the correctness of the proposed scheme.

  12. Experimental and numerical studies of burning velocities and kinetic modeling for practical and surrogate fuels

    Science.gov (United States)

    Zhao, Zhenwei

    To help understand the fuel oxidation process in practical combustion environments, laminar flame speeds and high temperature chemical kinetic models were studied for several practical fuels and "surrogate" fuels, such as propane, dimethyl ether (DME), and primary reference fuel (PRF) mixtures, gasoline and n-decane. The PIV system developed for the present work is described. The general principles for PIV measurements are outlined and the specific considerations are also reported. Laminar flame speeds were determined for propane/air over a range of equivalence ratios at initial temperature of 298 K, 500 K and 650 K and atmospheric pressure. Several data sets for propane/air laminar flame speeds with N 2 dilution are also reported. These results are compared to the literature data collected at the same conditions. The propane flame speed is also numerically calculated with a detailed kinetic model and multi component diffusion, including Soret effects. This thesis also presents experimentally determined laminar flame speeds for primary reference fuel (PRF) mixtures of n-heptane/iso-octane and real gasoline fuel at different initial temperature and at atmospheric pressure. Nitrogen dilution effects on the laminar flame speed are also studied for selected equivalence ratios at the same conditions. A minimization of detailed kinetic model for PRF mixtures on laminar flame speed conditions was performed and the measured flame speeds were compared with numerical predictions using this model. The measured laminar flame speeds of n-decane/air mixtures at 500 K and at atmospheric pressure with and without dilution were determined. The measured flame speeds are significantly different that those predicted using existing published kinetic models, including a model validated previously against high temperature data from flow reactor, jet-stirred reactor, shock tube ignition delay, and burner stabilized flame experiments. A significant update of this model is described which

  13. [Problem areas and examples of best practice in intersectoral medication treatment--a literature review].

    Science.gov (United States)

    Mehrmann, Lena; Ollenschläger, Günter

    2014-01-01

    Transitions between the outpatient and inpatient sector are a critical phase in medication treatment. This article provides an overview of published problem areas and examples of best practice in the intersectoral medication treatment. Data with regard to related problem areas and examples of best practice was collected in August 2011 by a systematic literature research. The relevant literature was identified using the following databases and search engines: MEDLINE, The Cochrane Library, EMBASE, Google, and Google Scholar. Additionally, a hand search was done on the websites of SpringerLink and Thieme Connect. The initial search yielded a total of 4,409 records which were further selected in two screening steps and analysed according to their relevance. Of the remaining 63 records, 3 exclusively described problem areas, 11 of them examples of best practice, and 49 provided information on both problem areas and examples of best practice with regard to intersectoral medication treatment. Among other things, problem areas include varying legal regulations in inpatient and outpatient medication treatment, drug therapy interruptions after hospital discharge, or deficits in communication and continuity of care. Examples of best practice are projects, programmes, initiatives, recommendations, and points to consider with respect to medication reconciliation, pharmaceutical support, or transitions of care. Problem areas as well as examples of best practice are mainly focused on the transition from inpatient to outpatient care. Copyright © 2013. Published by Elsevier GmbH.

  14. Simultaneous and Comparable Numerical Indicators of International, National and Local Collaboration Practices in English-Medium Astrophysics Research Papers

    Science.gov (United States)

    Méndez, David I.; Alcaraz, M. Ángeles

    2016-01-01

    Introduction: We report an investigation on collaboration practices in research papers published in the most prestigious English-medium astrophysics journals. Method: We propose an evaluation method based on three numerical indicators to study and compare, in absolute terms, three different types of collaboration (international, national and…

  15. Numerical investigation on practicability of reducing MCST by using grid spacer in a tight rod bundle

    International Nuclear Information System (INIS)

    Zhu, Xiaojing; Morooka, Shinichi; Oka, Yoshiaki

    2014-01-01

    Highlights: • Standard grid spacer design causes decreased heat transfer in a tight rod bundle. • Heat transfer is greatly enhanced by flow-enhancing features. • Swirling flow adversely affects the heat transfer downstream of grid spacer. • Enhanced heat transfer by existing grid spacer is limited in a short region. • Improved grid spacer can effectively reduce MCST. - Abstract: The numerical investigation was carried out to reveal the practicability of reducing the maximum cladding surface temperature (MCST) within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The special heat transfer and pressure drop characteristics caused by four existing grid spacer designs were discussed in detail by analyzing the effects of grid strap length, different flow enhancing features and different Reynolds numbers. It was found that the local heat transfer within the grid strap is greatly enhanced due to the raised flow velocity. Both the standard grid spacer and the grid spacer with split-vanes cause decreased heat transfer in the downstream region. The friction drag is very influential in the tight rod bundle and can eliminate the positive effect of flow blockage on the heat transfer performance. The grid spacer with flow blockage discs induces relatively good heat transfer performance and higher pressure drop within sub-channels, indicating a tradeoff between the heat transfer augmentation and the pressure drop. The combination of multiple existing grid spacers can reduce the MCST to a certain level, but the corresponding disadvantages cannot be ignored. The improved grid spacer design was proposed based on the overall considerations of heat transfer and pressure drop characteristics and has been proved more suitable to widely reduce MCST for SCWR than any other grid spacer designs involved in present study

  16. Solving the dynamic rupture problem with different numerical approaches and constitutive laws

    Science.gov (United States)

    Bizzarri, A.; Cocco, M.; Andrews, D.J.; Boschi, Enzo

    2001-01-01

    We study the dynamic initiation, propagation and arrest of a 2-D in-plane shear rupture by solving the elastodynamic equation by using both a boundary integral equation method and a finite difference approach. For both methods we adopt different constitutive laws: a slip-weakening (SW) law, with constant weakening rate, and rate- and state-dependent friction laws (Dieterich-Ruina). Our numerical procedures allow the use of heterogeneous distributions of constitutive parameters along the fault for both formulations. We first compare the two solution methods with an SW law, emphasizing the required stability conditions to achieve a good resolution of the cohesive zone and to avoid artificial complexity in the solutions. Our modelling results show that the two methods provide very similar time histories of dynamic source parameters. We point out that, if a careful control of resolution and stability is performed, the two methods yield identical solutions. We have also compared the rupture evolution resulting from an SW and a rate- and state-dependent friction law. This comparison shows that despite the different constitutive formulations, a similar behaviour is simulated during the rupture propagation and arrest. We also observe a crack tip bifurcation and a jump in rupture velocity (approaching the P-wave speed) with the Dieterich-Ruina (DR) law. The rupture arrest at a barrier (high strength zone) and the barrier-healing mechanism are also reproduced by this law. However, this constitutive formulation allows the simulation of a more general and complex variety of rupture behaviours. By assuming different heterogeneous distributions of the initial constitutive parameters, we are able to model a barrier-healing as well as a self-healing process. This result suggests that if the heterogeneity of the constitutive parameters is taken into account, the different healing mechanisms can be simulated. We also study the nucleation phase duration Tn, defined as the time

  17. Blended learning as a solution to practice-related problems in vocational schools

    DEFF Research Database (Denmark)

    Kjærgaard, Hanne Wacher; Duch, Henriette Skjærbæk; Mark, Lene

    Four different types of vocational schools have experimented with blended learning as a way of dealing with problems faced in their students’ theoretical and practical training and the interplay between these. A large part of this has involved the need for differentiated teaching...... as will be illustrated through selected cases. The foci of the cases are: •How can students be part of school-based teaching and learning during periods of practical training? •How can authentic practice be brought into school-based practical training? •How may blended learning assist and support students who...... are otherwise challenged in terms of meeting the prescribed competence goals? Methodologically, scenarios have been employed as a tool for defining the practice-related problems teachers meet in their practice and describing ways in which blended learning may present solutions. Subsequently, the solutions have...

  18. A Differential Quadrature Procedure with Regularization of the Dirac-delta Function for Numerical Solution of Moving Load Problem

    Directory of Open Access Journals (Sweden)

    S. A. Eftekhari

    Full Text Available AbstractThe differential quadrature method (DQM is one of the most elegant and efficient methods for the numerical solution of partial differential equations arising in engineering and applied sciences. It is simple to use and also straightforward to implement. However, the DQM is well-known to have some difficulty when applied to partial differential equations involving singular functions like the Dirac-delta function. This is caused by the fact that the Dirac-delta function cannot be directly discretized by the DQM. To overcome this difficulty, this paper presents a simple differential quadrature procedure in which the Dirac-delta function is replaced by regularized smooth functions. By regularizing the Dirac-delta function, such singular function is treated as non-singular functions and can be easily and directly discretized using the DQM. To demonstrate the applicability and reliability of the proposed method, it is applied here to solve some moving load problems of beams and rectangular plates, where the location of the moving load is described by a time-dependent Dirac-delta function. The results generated by the proposed method are compared with analytical and numerical results available in the literature. Numerical results reveal that the proposed method can be used as an efficient tool for dynamic analysis of beam- and plate-type structures traversed by moving dynamic loads.

  19. A Pilot Study of Problems and Practices in the Induction of Beginning Teachers.

    Science.gov (United States)

    Bouchard, John B.; Hull, Ronald E.

    A pilot study was designed to test the practicality of gathering data through interviews and to provide tentative information on induction problems and practices encountered by beginning teachers in the Cattaraugus-Chautauqua County area of New York. Fifty-three elementary self-contained classroom teachers and secondary academic subject-matter…

  20. Numerical solution of the state-delayed optimal control problems by a fast and accurate finite difference θ-method

    Science.gov (United States)

    Hajipour, Mojtaba; Jajarmi, Amin

    2018-02-01

    Using the Pontryagin's maximum principle for a time-delayed optimal control problem results in a system of coupled two-point boundary-value problems (BVPs) involving both time-advance and time-delay arguments. The analytical solution of this advance-delay two-point BVP is extremely difficult, if not impossible. This paper provides a discrete general form of the numerical solution for the derived advance-delay system by applying a finite difference θ-method. This method is also implemented for the infinite-time horizon time-delayed optimal control problems by using a piecewise version of the θ-method. A matrix formulation and the error analysis of the suggested technique are provided. The new scheme is accurate, fast and very effective for the optimal control of linear and nonlinear time-delay systems. Various types of finite- and infinite-time horizon problems are included to demonstrate the accuracy, validity and applicability of the new technique.

  1. Incorporating the Common Core's Problem Solving Standard for Mathematical Practice into an Early Elementary Inclusive Classroom

    Science.gov (United States)

    Fletcher, Nicole

    2014-01-01

    Mathematics curriculum designers and policy decision makers are beginning to recognize the importance of problem solving, even at the earliest stages of mathematics learning. The Common Core includes sense making and perseverance in solving problems in its standards for mathematical practice for students at all grade levels. Incorporating problem…

  2. Evaluating an Art-Based Intervention to Improve Practicing Nurses' Observation, Description, and Problem Identification Skills.

    Science.gov (United States)

    Nease, Beth M; Haney, Tina S

    Astute observation, description, and problem identification skills provide the underpinning for nursing assessment, surveillance, and prevention of failure to rescue events. Art-based education has been effective in nursing schools for improving observation, description, and problem identification. The authors describe a randomized controlled pilot study testing the effectiveness of an art-based educational intervention aimed at improving these skills in practicing nurses.

  3. Financial Stress, Parental Depressive Symptoms, Parenting Practices, and Children's Externalizing Problem Behaviors: Underlying Processes

    Science.gov (United States)

    Lee, Chih-Yuan Steven; Lee, Jaerim; August, Gerald J.

    2011-01-01

    This study examined the relationships among financial stress encountered by families, parents' social support, parental depressive symptoms, parenting practices, and children's externalizing problem behaviors to advance our understanding of the processes by which family financial stress is associated with children's problem behaviors. We also…

  4. Problem-Posing in Education: Transformation of the Practice of the Health Professional.

    Science.gov (United States)

    Casagrande, L. D. R.; Caron-Ruffino, M.; Rodrigues, R. A. P.; Vendrusculo, D. M. S.; Takayanagui, A. M. M.; Zago, M. M. F.; Mendes, M. D.

    1998-01-01

    Studied the use of a problem-posing model in health education. The model based on the ideas of Paulo Freire is presented. Four innovative experiences of teaching-learning in environmental and occupational health and patient education are reported. Notes that the problem-posing model has the capability to transform health-education practice.…

  5. Bound-state problem in the light-front Tamm-Dancoff approximation: Numerical study in 1+1 dimensions

    International Nuclear Information System (INIS)

    Harindranath, A.; Perry, R.J.; Shigemitsu, J.

    1992-01-01

    Numerical solutions to the two-fermion bound-state problem in the (1+1)-dimensional Yukawa model are presented within the lowest-order light-front Tamm-Dancoff approximation (i.e., keeping only two-fermion and two-fermion--one-boson sectors). Our motivation is twofold. First, we want to understand the dynamics of the model from the very-weak-coupling domain, where the system is governed by nonrelativistic dynamics, to moderate and strong-coupling domains where retardation and self-energy effects become important. Second, we want to develop techniques for solving coupled Tamm-Dancoff integral equations, in particular, methods that can be generalized to higher-order Tamm-Dancoff approximations. To achieve the first goal we first simplify the problem considerably (from a numerical point of view) by the explicit elimination of the higher Fock-space sector. The resulting integral equation, whose kernel depends upon the invariant mass of the state, is solved for the coupling constant, for a given set of the invariant mass and fermion and boson mass parameters. To achieve the second goal we solve the coupled set of equations using both basis functions and direct-discretization techniques. Results from these more general techniques are compared with the explicit-elimination method

  6. A LONGITUDINAL ANALYSIS OF PARENTING PRACTICES, COUPLE SATISFACTION, AND CHILD BEHAVIOR PROBLEMS

    OpenAIRE

    Linville, Deanna; Chronister, Krista; Dishion, Tom; Todahl, Jeff; Miller, John; Shaw, Daniel; Gardner, Francis; Wilson, Melvin

    2010-01-01

    This longitudinal study examined the relationship between couple relationship satisfaction, parenting practices, parent depression, and child problem behaviors. The study participants (n = 148) were part of a larger experimental study that examined the effectiveness of a brief family-centered intervention, the Family Check-Up model. Regression analysis results indicated that our proposed model accounted for 38% of the variance in child problem behavior at Time 2, with child problem behavior a...

  7. Excel 2016 for biological and life sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2016-01-01

    This book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical biological and life science problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel is an effective learning tool for quantitative analyses in biological and life sciences courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Biological and Life Sciences Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel 2016 to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs the reader to use Excel commands to solve specific, easy-to-understand biological and life science problems. Practice problems are provided...

  8. Excel 2016 for physical sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2016-01-01

    This book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical physical science problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel is an effective learning tool for quantitative analyses in environmental science courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Physical Sciences Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel 2016 to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs the reader to use Excel commands to solve specific, easy-to-understand physical science problems. Practice problems are provided at the end of each chapter with their s...

  9. Excel 2016 for environmental sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2016-01-01

    This book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical environmental science problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel is an effective learning tool for quantitative analyses in environmental science courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Environmental Science Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel 2016 to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs the reader to use Excel commands to solve specific, easy-to-understand environmental science problems. Practice problems are provided at the end of each chapte...

  10. Practical adjoint Monte Carlo technique for fixed-source and eigenfunction neutron transport problems

    International Nuclear Information System (INIS)

    Hoogenboom, J.E.

    1981-01-01

    An adjoint Monte Carlo technique is described for the solution of neutron transport problems. The optimum biasing function for a zero-variance collision estimator is derived. The optimum treatment of an analog of a non-velocity thermal group has also been derived. The method is extended to multiplying systems, especially for eigenfunction problems to enable the estimate of averages over the unknown fundamental neutron flux distribution. A versatile computer code, FOCUS, has been written, based on the described theory. Numerical examples are given for a shielding problem and a critical assembly, illustrating the performance of the FOCUS code. 19 refs

  11. The Robin Hood method - A novel numerical method for electrostatic problems based on a non-local charge transfer

    International Nuclear Information System (INIS)

    Lazic, Predrag; Stefancic, Hrvoje; Abraham, Hrvoje

    2006-01-01

    We introduce a novel numerical method, named the Robin Hood method, of solving electrostatic problems. The approach of the method is closest to the boundary element methods, although significant conceptual differences exist with respect to this class of methods. The method achieves equipotentiality of conducting surfaces by iterative non-local charge transfer. For each of the conducting surfaces, non-local charge transfers are performed between surface elements, which differ the most from the targeted equipotentiality of the surface. The method is tested against analytical solutions and its wide range of application is demonstrated. The method has appealing technical characteristics. For the problem with N surface elements, the computational complexity of the method essentially scales with N α , where α < 2, the required computer memory scales with N, while the error of the potential decreases exponentially with the number of iterations for many orders of magnitude of the error, without the presence of the Critical Slowing Down. The Robin Hood method could prove useful in other classical or even quantum problems. Some future development ideas for possible applications outside electrostatics are addressed

  12. Pediatrician identification of child behavior problems: the roles of parenting factors and cross-practice differences.

    Science.gov (United States)

    Dempster, Robert M; Wildman, Beth G; Langkamp, Diane; Duby, John C

    2012-06-01

    While most primary care pediatricians acknowledge the importance of identifying child behavior problems, fewer than 2% of children with a diagnosable psychological disorder are referred for mental health care in any given year. The present study examined the potential role of parental characteristics (parental affect, parenting style, and parenting self-efficacy) in pediatrician identification of child behavior problems, and determined whether these relationships differed across practices. Parents of 831 children between 2 and 16 years completed questionnaires regarding demographic information, their child's behavior, their affect, their parenting style, and their parenting self-efficacy. Pediatricians completed a brief questionnaire following visits in four community-based primary care practices in the Midwest. Logistic regressions controlling for child behavior and demographic predictors of pediatrician identification found that an authoritarian parenting style, in which parents yell or strongly negatively react to problem behavior, was negatively associated with likelihood of identification in the overall sample. However, the variables that were predictive of pediatrician identification differed depending on the specific practice. Parental characteristics can aid in understanding which children are likely to be identified by their pediatrician as having behavioral problems. The finding that practices differed on which variables were associated with pediatrician identification suggests the need to potentially individualize interventions to certain physicians and practices to improve identification of child behavior problems in primary care.

  13. Comparing Psychology Undergraduates' Performance in Probabilistic Reasoning under Verbal-Numerical and Graphical-Pictorial Problem Presentation Format: What Is the Role of Individual and Contextual Dimensions?

    Science.gov (United States)

    Agus, Mirian; Peró-Cebollero, Maribel; Penna, Maria Pietronilla; Guàrdia-Olmos, Joan

    2015-01-01

    This study aims to investigate about the existence of a graphical facilitation effect on probabilistic reasoning. Measures of undergraduates' performances on problems presented in both verbal-numerical and graphical-pictorial formats have been related to visuo-spatial and numerical prerequisites, to statistical anxiety, to attitudes towards…

  14. Multiconfiguration time-dependent self-consistent field approximations in the numerical solution of quantum dynamical problems

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, Z.; Neria, E.; Nitzan, A. (Tel Aviv Univ. (Israel). School of Chemistry)

    1991-02-01

    The use of the time-dependent self-consistent field approximation (TDSCF) in the numerical solution of quantum curve crossing and tunneling dynamical problems is investigated. Particular emphasis is given to multiconfiguration TDSCF (MCTDSCF) approximations, which are shown to perform considerably better with only a small increase in computational effort. We investigate a number of simple models in which a 'system' characterized by two electronic potential surfaces evolves while interacting with a 'bath' mode described by an harmonic oscillator, and compare exact numerical solutions to one- and two-configuration TDSCF approximations. We also introduce and investigate a semiclassical approximation in which the 'bath' mode is described by semiclassical wavepackets (one for each electronic state) and show that for all models investigated this scheme works very well in comparison with the fully quantum MCTDSCF approximation. This provides a potentially very useful method to simulate strongly quantum systems coupled to an essentially classical environment. (orig.).

  15. The development of high performance numerical simulation code for transient groundwater flow and reactive solute transport problems based on local discontinuous Galerkin method

    International Nuclear Information System (INIS)

    Suzuki, Shunichi; Motoshima, Takayuki; Naemura, Yumi; Kubo, Shin; Kanie, Shunji

    2009-01-01

    The authors develop a numerical code based on Local Discontinuous Galerkin Method for transient groundwater flow and reactive solute transport problems in order to make it possible to do three dimensional performance assessment on radioactive waste repositories at the earliest stage possible. Local discontinuous Galerkin Method is one of mixed finite element methods which are more accurate ones than standard finite element methods. In this paper, the developed numerical code is applied to several problems which are provided analytical solutions in order to examine its accuracy and flexibility. The results of the simulations show the new code gives highly accurate numeric solutions. (author)

  16. Numerical solution of a coefficient inverse problem with multi-frequency experimental raw data by a globally convergent algorithm

    Science.gov (United States)

    Nguyen, Dinh-Liem; Klibanov, Michael V.; Nguyen, Loc H.; Kolesov, Aleksandr E.; Fiddy, Michael A.; Liu, Hui

    2017-09-01

    We analyze in this paper the performance of a newly developed globally convergent numerical method for a coefficient inverse problem for the case of multi-frequency experimental backscatter data associated to a single incident wave. These data were collected using a microwave scattering facility at the University of North Carolina at Charlotte. The challenges for the inverse problem under the consideration are not only from its high nonlinearity and severe ill-posedness but also from the facts that the amount of the measured data is minimal and that these raw data are contaminated by a significant amount of noise, due to a non-ideal experimental setup. This setup is motivated by our target application in detecting and identifying explosives. We show in this paper how the raw data can be preprocessed and successfully inverted using our inversion method. More precisely, we are able to reconstruct the dielectric constants and the locations of the scattering objects with a good accuracy, without using any advanced a priori knowledge of their physical and geometrical properties.

  17. Excel 2016 for social work statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2017-01-01

    This text is a step-by-step guide for students taking a first course in statistics for social work and for social work managers and practitioners who want to learn how to use Excel to solve practical statistics problems in in the workplace, whether or not they have taken a course in statistics. There is no other text for a first course in social work statistics that teaches students, step-by-step, how to use Excel to solve interesting social work statistics problems. Excel 2016 for Social Work Statistics explains statistical formulas and offers practical examples for how students can solve real-world social work statistics problems. This book leaves detailed explanations of statistical theory to other statistics textbooks and focuses entirely on practical, real-world problem solving. Each chapter briefly explains a topic and then demonstrates how to use Excel commands and formulas to solve specific social work statistics problems.  This book gives practice in using Excel in two different ways:  (1) writing ...

  18. INNOVATION IN ORGANIC CHEMISTRY PRACTICAL WORKS, USING PROBLEM-BASED LEARNING AS TEACHING STRATEGY

    OpenAIRE

    Miriam G. Acuña; Nora M. Sosa; Eusebia C. Valdez

    2011-01-01

    This paper presents the teaching strategy known as problem-based learning as an innovation implemented in the practical experiences of the Organic Chemistry course (Bachelor of Genetics), Faculty of Exact, Chemical and Natural Sciences (Universidad Nacional de Misiones, Argentina). It reviews the results of the experience implemented with students, in groups of 7 selected according to their preferences. A problem that required skills in planning, decision making process, thinking, using of ap...

  19. The Ethical Problems of Reserach : An empirical study of ethics in research practice

    OpenAIRE

    Colnerud, Gunnel

    2013-01-01

    Most accounts of the ethical problems facing researchers across a broad spectrum of research fields come from ethicists, ethics committees and specialists committed to the study of ethics in human research. In contrast, this study reports on the ethical questions that researchers, themselves, report facing in their everyday practice. Fifty-five Swedish researchers contributed 109 examples of ethical dilemmas, conflicts and problems in research. They were all researchers at the post-doctoral l...

  20. Practical Fluid Therapy and Treatment Modalities for Field Conditions for Horses and Foals with Gastrointestinal Problems.

    Science.gov (United States)

    Fielding, C Langdon

    2018-04-01

    With advances in technology and owner education, field management in equine veterinary medicine continues to evolve. Equine gastrointestinal disease is one of the most common types of emergencies evaluated by equine practitioners, and many of these patients can be effectively managed in the field. Although the equine veterinarian must make numerous decisions, fluid therapy, pain management, and antimicrobial use are 3 of the major choices that must be addressed when initiating field treatment of equine gastrointestinal disease. This article addresses the practical use of these 3 treatment categories that are essential to field practice. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Do longer consultations improve the management of psychological problems in general practice? A systematic literature review

    Directory of Open Access Journals (Sweden)

    Hutton Catherine

    2007-05-01

    Full Text Available Abstract Background Psychological problems present a huge burden of illness in our community and GPs are the main providers of care. There is evidence that longer consultations in general practice are associated with improved quality of care; but this needs to be balanced against the fact that doctor time is a limited resource and longer consultations may lead to reduced access to health care. The aim of this research was to conduct a systematic literature review to determine whether management of psychological problems in general practice is associated with an increased consultation length and to explore whether longer consultations are associated with better health outcomes for patients with psychological problems. Methods A search was conducted on Medline (Ovid databases up to7 June 2006. The following search terms, were used: general practice or primary health care (free text or family practice (MeSH AND consultation length or duration (free text or time factors (MeSH AND depression or psychological problems or depressed (free text. A similar search was done in Web of Science, Pubmed, Google Scholar, and Cochrane Library and no other papers were found. Studies were included if they contained data comparing consultation length and management or detection of psychological problems in a general practice or primary health care setting. The studies were read and categories developed to enable systematic data extraction and synthesis. Results 29 papers met the inclusion criteria. Consultations with a recorded diagnosis of a psychological problem were reported to be longer than those with no recorded psychological diagnosis. It is not clear if this is related to the extra time or the consultation style. GPs reported that time pressure is a major barrier to treating depression. There was some evidence that increased consultation length is associated with more accurate diagnosis of psychological problems. Conclusion Further research is needed to

  2. Community problem-solving framed as a distributed information use environment: bridging research and practice

    Directory of Open Access Journals (Sweden)

    Joan C. Durrance

    2006-01-01

    Full Text Available Introduction. This article results from a qualitative study of 1 information behavior in community problem-solving framed as a distributed information use environment and 2 approaches used by a best-practice library to anticipate information needs associated with community problem solving. Method. Several approaches to data collection were used - focus groups, interviews, observation of community and library meetings, and analysis of supporting documents. We focused first on the information behaviour of community groups. Finding that the library supported these activities we sought to understand its approach. Analysis. Data were coded thematically for both information behaviour concepts and themes germane to problem-solving activity. A grounded theory approach was taken to capture aspects of the library staff's practice. Themes evolved from the data; supporting documentation - reports, articles and library communication - was also coded. Results. The study showed 1 how information use environment components (people, setting, problems, problem resolutions combine in this distributed information use environment to determine specific information needs and uses; and 2 how the library contributed to the viability of this distributed information use environment. Conclusion. Community problem solving, here explicated as a distributed IUE, is likely to be seen in multiple communities. The library model presented demonstrates that by reshaping its information practice within the framework of an information use environment, a library can anticipate community information needs as they are generated and where they are most relevant.

  3. Brain potentials during mental arithmetic: effects of extensive practice and problem difficulty.

    Science.gov (United States)

    Pauli, P; Lutzenberger, W; Rau, H; Birbaumer, N; Rickard, T C; Yaroush, R A; Bourne, L E

    1994-07-01

    Recent behavioral investigations indicate that the processes underlying mental arithmetic change systematically with practice from deliberate, conscious calculation to automatic, direct retrieval of answers from memory [Bourne, L.E.Jr. and Rickard, T.C., Mental calculation: The development of a cognitive skill, Paper presented at the Interamerican Congress of Psychology, San Jose, Costa Rica, 1991: Psychol. Rev., 95 (1988) 492-527]. Results reviewed by Moscovitch and Winocur [In: The handbook of aging and cognition, Erlbaum, Hillsdale, NJ, 1992, pp. 315-372] suggest that consciously controlled processes are more dependent on frontal lobe function than are automatic processes. It is appropriate, therefore to determine whether transitions in the locus of primary brain activity occur with practice on mental calculation. In this experiment, we examine the relationship between characteristics of event-related brain potentials (ERPs) and mental arithmetic. Single-digit mental multiplication problems varying in difficulty (problem size) were used, and subjects were trained on these problems for four sessions. Problem-size and practice effects were reliably found in behavioral measures (RT). The ERP was characterized by a pronounced late positivity after task presentation followed by a slow wave, and a negativity during response indication. These components responded differentially to the practice and problem-size manipulations. Practice mainly affected topography of the amplitude of positivity and offset latency of slow wave, and problem-size mainly offset latency of slow wave and pre-response negativity. Fronto-central positivity diminished from session to session, and the focus of positivity centered finally at centro-parietal regions.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Numerical modelling of mine workings.

    CSIR Research Space (South Africa)

    Lightfoot, N

    1999-03-01

    Full Text Available to cover most of what is required for a practising rock mechanics engineer to be able to use any of these five programs to solve practical mining problems. The chapters on specific programs discuss their individual strengths and weaknesses and highlight... and applications of numerical modelling in the context of the South African gold and platinum mining industries. This includes an example that utilises a number of different numerical 3 modelling programs to solve a single problem. This particular example...

  5. Riemann solvers and numerical methods for fluid dynamics a practical introduction

    CERN Document Server

    Toro, Eleuterio F

    2009-01-01

    High resolution upwind and centred methods are a mature generation of computational techniques applicable to a range of disciplines, Computational Fluid Dynamics being the most prominent. This book gives a practical presentation of this class of techniques.

  6. Research on the Numerical Simulation of Sleeper in the Pipeline Global Buckling Controlling Practice

    Directory of Open Access Journals (Sweden)

    Liu Wen-Bin

    2017-01-01

    Full Text Available This paper analyzed the lateral buckling of pipelines located in Western Africa with ABAQUS software. The application of sleepers in practice is explored to guide the pipeline buckling controlling design.

  7. Numerical method for the eigenvalue problem and the singular equation by using the multi-grid method and application to ordinary differential equation

    International Nuclear Information System (INIS)

    Kanki, Takashi; Uyama, Tadao; Tokuda, Shinji.

    1995-07-01

    In the numerical method to compute the matching data which are necessary for resistive MHD stability analyses, it is required to solve the eigenvalue problem and the associated singular equation. An iterative method is developed to solve the eigenvalue problem and the singular equation. In this method, the eigenvalue problem is replaced with an equivalent nonlinear equation and a singular equation is derived from Newton's method for the nonlinear equation. The multi-grid method (MGM), a high speed iterative method, can be applied to this method. The convergence of the eigenvalue and the eigenvector, and the CPU time in this method are investigated for a model equation. It is confirmed from the numerical results that this method is effective for solving the eigenvalue problem and the singular equation with numerical stability and high accuracy. It is shown by improving the MGM that the CPU time for this method is 50 times shorter than that of the direct method. (author)

  8. Can parenting practices predict externalizing behavior problems among children with hearing impairment?

    Science.gov (United States)

    Pino, María J; Castillo, Rosa A; Raya, Antonio; Herruzo, Javier

    2017-11-09

    To identify possible differences in the level of externalizing behavior problems among children with and without hearing impairment and determine whether any relationship exists between this type of problem and parenting practices. The Behavior Assessment System for Children was used to evaluate externalizing variables in a sample of 118 boys and girls divided into two matched groups: 59 with hearing disorders and 59 normal-hearing controls. Significant between-group differences were found in hyperactivity, behavioral problems, and externalizing problems, but not in aggression. Significant differences were also found in various aspects of parenting styles. A model for predicting externalizing behavior problems was constructed, achieving a predicted explained variance of 50%. Significant differences do exist between adaptation levels in children with and without hearing impairment. Parenting style also plays an important role.

  9. Can parenting practices predict externalizing behavior problems among children with hearing impairment?

    Directory of Open Access Journals (Sweden)

    María J. Pino

    2017-11-01

    Full Text Available Objective: To identify possible differences in the level of externalizing behavior problems among children with and without hearing impairment and determine whether any relationship exists between this type of problem and parenting practices. Methods: The Behavior Assessment System for Children was used to evaluate externalizing variables in a sample of 118 boys and girls divided into two matched groups: 59 with hearing disorders and 59 normal-hearing controls. Results: Significant between-group differences were found in hyperactivity, behavioral problems, and externalizing problems, but not in aggression. Significant differences were also found in various aspects of parenting styles. A model for predicting externalizing behavior problems was constructed, achieving a predicted explained variance of 50%. Conclusion: Significant differences do exist between adaptation levels in children with and without hearing impairment. Parenting style also plays an important role.

  10. General practice-based clinical trials in Germany - a problem analysis

    Directory of Open Access Journals (Sweden)

    Hummers-Pradier Eva

    2012-11-01

    Full Text Available Abstract Background In Germany, clinical trials and comparative effectiveness studies in primary care are still very rare, while their usefulness has been recognised in many other countries. A network of researchers from German academic general practice has explored the reasons for this discrepancy. Methods Based on a comprehensive literature review and expert group discussions, problem analyses as well as structural and procedural prerequisites for a better implementation of clinical trials in German primary care are presented. Results In Germany, basic biomedical science and technology is more reputed than clinical or health services research. Clinical trials are funded by industry or a single national programme, which is highly competitive, specialist-dominated, exclusive of pilot studies, and usually favours innovation rather than comparative effectiveness studies. Academic general practice is still not fully implemented, and existing departments are small. Most general practitioners (GPs work in a market-based, competitive setting of small private practices, with a high case load. They have no protected time or funding for research, and mostly no research training or experience. Good Clinical Practice (GCP training is compulsory for participation in clinical trials. The group defined three work packages to be addressed regarding clinical trials in German general practice: (1 problem analysis, and definition of (2 structural prerequisites and (3 procedural prerequisites. Structural prerequisites comprise specific support facilities for general practice-based research networks that could provide practices with a point of contact. Procedural prerequisites consist, for example, of a summary of specific relevant key measures, for example on a web platform. The platform should contain standard operating procedures (SOPs, templates, checklists and other supporting materials for researchers. Conclusion All in all, our problem analyses revealed that

  11. Consultations for mental problems in general practices with and without mental health nurses.

    NARCIS (Netherlands)

    Magnée, T.; Beurs, D. de; Verhaak, P.

    2016-01-01

    Background & Aim: It seems cost-effective to provide mental health care to patient with mild mental problems in general practices instead of in specialized care, but general practitioners (GPs) often lack time or expertise. Since 2008, Dutch GPs have been collaborating with nurses with mental health

  12. The problem of modernization of the high-pressure pipelines clampers - Practice

    International Nuclear Information System (INIS)

    Komorowski, J.; Zajaczkowski, P.; Szteke, W.

    2008-01-01

    In the paper the problems connected with the modernization and repair of the clampers of high-pressure pipelines joining the boiler with the turbine, on the basis of authors experiences are presented. The basic scope of requirements and practice recommendation are also done. (author)

  13. Mathematics Teaching as Problem Solving: A Framework for Studying Teacher Metacognition Underlying Instructional Practice in Mathematics.

    Science.gov (United States)

    Artzt, Alice F.; Armour-Thomas, Eleanor

    1998-01-01

    Uses a "teaching as problem solving" perspective to examine the components of metacognition underlying the instructional practice of seven experienced and seven beginning secondary-school mathematics teachers. Data analysis of observations, lesson plans, videotapes, and audiotapes of structured interviews suggests that the metacognition of…

  14. Problems of Chernobyl. Materials of International scientific and practical conference 'Shelter-98'

    International Nuclear Information System (INIS)

    Klyuchnikov, O.O.

    1999-01-01

    These transactions contain materials of International Scientific and Practical Conference 'Shelter-98', which was held 27-30 November 1998 in Slavutich. They describe the results of the research work of the specialists from Ukraine, neighborhood and far foreign counties. The results, targeted at solving the problems of converting the Shelter Object into oncologically safe state

  15. Enhancing Arithmetic and Word-Problem Solving Skills Efficiently by Individualized Computer-Assisted Practice

    Science.gov (United States)

    Schoppek, Wolfgang; Tulis, Maria

    2010-01-01

    The fluency of basic arithmetical operations is a precondition for mathematical problem solving. However, the training of skills plays a minor role in contemporary mathematics instruction. The authors proposed individualization of practice as a means to improve its efficiency, so that the time spent with the training of skills is minimized. As a…

  16. Evaluating Remote Reference Service: A Practical Guide to Problems and Solutions

    Science.gov (United States)

    Pomerantz, Jeffrey; Mon, Lorri; McClure, Charles R.

    2008-01-01

    This paper identifies key methodological issues affecting quality of data in the evaluation of remote reference services. Despite a growing number of studies in this area, no comprehensive effort has been made to identify potential problems and suggest solutions. The strategies proposed in this paper offer practical ways in which libraries can…

  17. Excel 2016 for advertising statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2017-01-01

    This text is a step-by-step guide for students taking a first course in statistics for advertising and for advertising managers and practitioners who want to learn how to use Excel to solve practical statistics problems in in the workplace, whether or not they have taken a course in statistics. Excel 2016 for Advertising Statistics explains statistical formulas and offers practical examples for how students can solve real-world advertising statistics problems. This book leaves detailed explanations of statistical theory to other statistics textbooks and focuses entirely on practical, real-world problem solving. Each chapter briefly explains a topic and then demonstrates how to use Excel commands and formulas to solve specific advertising statistics problems.  This book gives practice in using Excel in two different ways:  (1) writing formulas (e.g., confidence interval about the mean, one-group t-test, two-group t-test, correlation) and (2) using Excel’s drop-down formula menus (e.g., simple linear regres...

  18. Practical solution of plastic deformation problems in elastic-plastic range

    Science.gov (United States)

    Mendelson, A; Manson, S

    1957-01-01

    A practical method for solving plastic deformation problems in the elastic-plastic range is presented. The method is one of successive approximations and is illustrated by four examples which include a flat plate with temperature distribution across the width, a thin shell with axial temperature distribution, a solid cylinder with radial temperature distribution, and a rotating disk with radial temperature distribution.

  19. Parent Training among Ethnic Minorities: Parenting Practices as Mediators of Change in Child Conduct Problems

    Science.gov (United States)

    Bjorknes, Ragnhild; Kjobli, John; Manger, Terje; Jakobsen, Reidar

    2012-01-01

    In this study, we examined parenting practices as mediators of changes in child conduct problems in ethnic minority families participating in Parent Management Training-Oregon Model (PMTO). The participants included 96 Somali and Pakistani immigrant mothers and their children living in Norway. The families were randomized to PMTO or a waiting-list…

  20. Numerical Modelling of the Weight-Bearing Total Knee Joint Replacement and Usage in Practice

    Czech Academy of Sciences Publication Activity Database

    Daněk, Josef; Nedoma, Jiří; Hlaváček, Ivan; Vavřík, P.; Denk, F.

    2007-01-01

    Roč. 76, č. 1-3 (2007), s. 49-56 ISSN 0378-4754 R&D Projects: GA MPO FT-TA/087 Institutional research plan: CEZ:AV0Z10300504 Keywords : total knee joint replacement * contact problem * non-overlapping domain decomposition method Subject RIV: BA - General Mathematics Impact factor: 0.738, year: 2007

  1. The Model of Problem Based Learning in Practice: Evidence from Aalborg University

    DEFF Research Database (Denmark)

    Turcan, Romeo V.

    into practice when they go through solving such problems. At the end of the day, the PBL based teaching is assessed based on the success of the problems solved, e.g., in the form of solution(s) provided, their creativity, innovation and applicability. Moreover, PBL-based teaching can identify theoretical gaps......The aim of this paper is to share an experience from Aalborg University on the application of Problem Based Learning (PBL) model, with a specific example from a bachelor studies. PBL model has now been acknowledged worldwide as a powerful tool that allows students, faculty members and industry...... practitioners engage in multi-disciplinary, collaborative and geographically distributed activities. The key word in the model is ‘problem’ – a problem that is correctly formulated eventually affects the process of learning. It is also linked to the intended outcome of the PBL based teaching, whereby students...

  2. Frequent attenders in general practice: problem solving treatment provided by nurses [ISRCTN51021015

    Directory of Open Access Journals (Sweden)

    van Oppen P

    2005-10-01

    Full Text Available Abstract Background There is a need for assistance from primary care mental health workers in general practice in the Netherlands. General practitioners (GPs experience an overload of frequent attenders suffering from psychological problems. Problem Solving Treatment (PST is a brief psychological treatment tailored for use in a primary care setting. PST is provided by nurses, and earlier research has shown that it is a treatment at least as effective as usual care. However, research outcomes are not totally satisfying. This protocol describes a randomized clinical trial on the effectiveness of PST provided by nurses for patients in general practice. The results of this study, which currently being carried out, will be presented as soon as they are available. Methods/design This study protocol describes the design of a randomized controlled trial to investigate the effectiveness and cost-effectiveness of PST and usual care compared to usual care only. Patients, 18 years and older, who present psychological problems and are frequent attenders in general practice are recruited by the research assistant. The participants receive questionnaires at baseline, after the intervention, and again after 3 months and 9 months. Primary outcome is the reduction of symptoms, and other outcomes measured are improvement in problem solving skills, psychological and physical well being, daily functioning, social support, coping styles, problem evaluation and health care utilization. Discussion Our results may either confirm that PST in primary care is an effective way of dealing with emotional disorders and a promising addition to the primary care in the UK and USA, or may question this assumption. This trial will allow an evaluation of the effects of PST in practical circumstances and in a rather heterogeneous group of primary care patients. This study delivers scientific support for this use and therefore indications for optimal treatment and referral.

  3. KNOWLEDGE ABOUT MENSTRUAL PROBLEMS AND MENSTRUAL HYGIENE PRACTICES AMONG COLLEGE GOING UNMARRIED GIRLS IN CHANDIGARH, INDIA

    Directory of Open Access Journals (Sweden)

    Amit Sachdeva

    2017-08-01

    Full Text Available BACKGROUND Menstruation is a vital part of the reproductive health of a woman. There is evident neglect of problems related to menstruation especially in young girls and they are lacking scientific knowledge regarding menstruation. The study was undertaken with the objective to assess the prevalence & patterns of menstrual problems, knowledge, belief, restrictions, menstrual hygiene and treatment seeking practice among college going unmarried girls of Chandigarh. MATERIALS AND METHODS A stratified multistage random sampling design was adopted for selection of participants from the selected colleges of Chandigarh. A total of 1000 girls who had attained menarche were selected. Information was collected through personal interviews conducted in privacy using semi -structured survey schedule. RESULTS The mean age of menarche was ± 13.89 years. Prior knowledge regarding menses was reported by 82.6% girls and 56.9% girls reported mother as the first source of information followed by 21.6% friends. 86.1% have regular menstrual history 86.8% of the respondents experienced pre menstrual syndrome while overall prevalence of menstrual problem in the present study was found 68.4%. Abdominal pain was the most common menstrual problem reported by 51.3% of participants having menstrual problems. 47.7% girls did not visit holy places during periods. 95.5% preferred sanitary napkins as menstrual absorbent. Treatment seeking behavior of the girls was poor and only about 34.9% of girls having menstrual problems approached for treatment. 72.4% of respondents were aware of emergency contraceptives. CONCLUSION The study revealed that there was an inappropriate knowledge and hygiene practice due to various Misconceptions, beliefs and taboos among college girls regarding menstruation. Reproductive health education in the school curriculum should be introduced for improving awareness regarding menstrual care practices.

  4. How doctors learn: the role of clinical problems across the medical school-to-practice continuum.

    Science.gov (United States)

    Slotnick, H B

    1996-01-01

    The author proposes a theory of how physicians learn that uses clinical problem solving as its central feature. His theory, which integrates insights from Maslow, Schön, Norman, and others, claims that physicians-in-training and practicing physicians learn largely by deriving insights from clinical experience. These insights allow the learner to solve future problems and thereby address the learner's basic human needs for security, affiliation, and self-esteem. Ensuring that students gain such insights means that the proper roles of the teacher are (1) to select problems for students to solve and offer guidance on how to solve them, and (2) to serve as a role model of how to reflect on the problem, its solution, and the solution's effectiveness. Three principles guide instruction within its framework for learning: (1) learners, whether physicians-in-training or practicing physicians, seek to solve problems they recognize they have; (2) learners want to be involved in their own learning; and (3) instruction must both be time-efficient and also demonstrate the range of ways in which students can apply what they learn. The author concludes by applying the theory to an aspect of undergraduate education and to the general process of continuing medical education.

  5. TRANING BACHELORS OF BUSINESS INFORMATICS TO SOLVE PRACTICAL PROBLEMS OF MARKETING

    Directory of Open Access Journals (Sweden)

    Л В Дегтярева

    2016-12-01

    Full Text Available In article need of an integrated approach is proved when training bachelors of business informatics for the solution of practical problems of marketing and the example of realization of such approach is given. The illustrated example proves need of use of an integrated approach for training of bachelors of business informatics, in particular, on such disciplines as the mathematics, informatics and marketing where theoretical knowledge uniting, give already synergetic effect in practical refraction. Such integration undergoes already biennial testing at our university and yields positive result.

  6. Numerical analysis of some problems related to the mechanics of pneumatic tires: Finite deformation/rolling contact of a viscoelastic cylinder and finite deformation of cord-reinforced rubber composites

    Science.gov (United States)

    Oden, J. T.; Becker, E. B.; Lin, T. L.; Hsieh, K. T.

    1984-01-01

    The formulation and numerical analysis of several problems related to the behavior of pneumatic tires are considered. These problems include the general rolling contact problem of a rubber-like viscoelastic cylinder undergoing finite deformations and the finite deformation of cord-reinforced rubber composites. New finite element models are developed for these problems. Numerical results obtained for several representative cases are presented.

  7. Excel 2016 for educational and psychological statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching educational and psychological statistics effectively. Similar to the previously published Excel 2013 for Educational and Psychological Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical education and psychology problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in education and psychology courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Educational and Psychological Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and man...

  8. Care erosion in hospitals: Problems in reflective nursing practice and the role of cognitive dissonance.

    Science.gov (United States)

    de Vries, Jan; Timmins, Fiona

    2016-03-01

    Care erosion - gradual decline in care level - is an important problem in health care today. Unfortunately, the mechanism whereby it occurs is complex and poorly understood. This paper seeks to address this by emphasising problems in reflective nursing practice. Critical reflection on quality of care which should drive good care instead spawns justifications, denial, and trivialisation of deficient care. This perpetuates increasingly poor care levels. We argue that cognitive dissonance theory provides a highly effective understanding of this process and suggest for this approach to be incorporated in all efforts to address care erosion. The paper includes a detailed discussion of examples and implications for practice, in particular the need to restore critical reflection in nursing, the importance of embracing strong values and standards, and the need for increased awareness of signs of care erosion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Excel 2013 for physical sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching physical sciences statistics effectively. Similar to the previously published Excel 2010 for Physical Sciences Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical science problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in science courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2013 for Physical Sciences Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their ...

  10. Excel 2016 for engineering statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching engineering statistics effectively. Similar to the previously published Excel 2013 for Engineering Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical engineering problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in engineering courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However,Excel 2016 for Engineering Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and...

  11. Excel 2010 for health services management statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2014-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach health services management statistics effectively. It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical health services management problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.   Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in health services management courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2010 for Health Services Management Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work....

  12. Excel 2013 for human resource management statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows how Microsoft Excel is able to teach human resource management statistics effectively. Similar to the previously published Excel 2010 for Human Resource Management Statistics, it is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical human resource management problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in human resource management courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2013 for Human Resource Management Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to ...

  13. Excel 2016 for business statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching business statistics effectively. Similar to the previously published Excel 2010 for Business Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical business problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in business courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Business Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each ch...

  14. Excel 2016 for human resource management statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching human resource management statistics effectively. Similar to the previously published Excel 2013 for Human Resource Management Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical human resource management problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in human resource management courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Human Resource Management Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how ...

  15. Excel 2013 for health services management statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel to teach health services management statistics effectively. Similar to the previously published Excel 2010 for Health Services Management Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical health services management problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in health services management courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2013 for Health Services Management Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers ho...

  16. Excel 2016 for marketing statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This is the first book to show the capabilities of Microsoft Excel in teaching marketing statistics effectively. It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical marketing problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in marketing courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Marketing Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs the reader t...

  17. Excel 2013 for educational and psychological statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach educational and psychological statistics effectively. It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical problems in education and psychology. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and practitioners, is also an effective teaching and learning tool for quantitative analyses in statistics courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2013 for Educational and Psychological Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and practitioners how to apply Excel to statistical techniques necessary in their courses and work. E...

  18. Excel 2016 for social science statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2016-01-01

    This book shows the capabilities of Microsoft Excel in teaching social science statistics effectively. Similar to the previously published Excel 2013 for Social Sciences Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical social science problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in social science courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2016 for Social Science Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in ...

  19. The Discursive Construction of Organizational Knowledge – Communication Theoretical Issues and Practical Problems

    DEFF Research Database (Denmark)

    Kastberg, Peter

    as in organizational practice, two camps exist. One holds that knowledge is basically information, i.e. a knowledge-as-representation view, and that organizational knowledge, therefore, can be gathered, produced and/or communicated by means of documents, databases etc. The other camp favors the radically different...... a communication theoretical problem, pertaining to lack of conceptual consistency and clarity (although it surely is that); it is also a problem for organizational communication practice. For if organizational knowledge is discursively constructed as a ‘thing’ (as representation) then it can indeed be harvested...... view, the prevailing organizational discourse becomes one of logistics; according to the second view, it becomes one of enabling. Each discourse gives rise to the communicative construction of fundamentally different organizations – and not only as far as organizational knowledge is concerned. I...

  20. Fixed Assets Fair Value and Historical Value – Practical Problems with Implementation and Interpretation

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawadzki

    2009-06-01

    Full Text Available The article presents practical problems with implementation of fixed assets fair value during the acquisition processes. This has influence on the financial statements making and their research by accouters and auditors. In the article, the author would like to find the solution, how the fair value can be used on valuation of fixed assets and which method of it is better during the financial crisis period.

  1. HMOs and physician recruiting: a survey of problems and methods among group practice plans.

    OpenAIRE

    Fink, R

    1981-01-01

    A mail survey was conducted among 69 group practice health maintenance organizations (HMOs) to collect information on the recruiting of primary care physicians and specialists. In reporting on difficulties in recruiting physicians for primary care, the medical directors of HMOs indicated that the greatest problem was locating obstetrician-gynecologists. Among specialists, recruiting for orthopedists was reported as being most difficult, although plans that employ neurologists and anesthesiolo...

  2. Practical problems in the verification of a family of inventory items

    International Nuclear Information System (INIS)

    Rota, A.; Stricht, E. van der; Stanners, W.

    1976-01-01

    This paper deals with the problem of checking medium-size families of items of similar specification during inventory verifications. An example of quantitative analysis using the signed rank test is given. The hypotheses commonly accepted in the statistical tests performed are extensively discussed. The difficulties met in practice which limit the application of the theory are pointed out and the solution adopted in the case considered is illustrated. (author)

  3. Medication management and practices in prison for people with mental health problems: a qualitative study.

    Science.gov (United States)

    Bowen, Robert A; Rogers, Anne; Shaw, Jennifer

    2009-10-20

    Common mental health problems are prevalent in prison and the quality of prison health care provision for prisoners with mental health problems has been a focus of critical scrutiny. Currently, health policy aims to align and integrate prison health services and practices with those of the National Health Service (NHS). Medication management is a key aspect of treatment for patients with a mental health problem. The medication practices of patients and staff are therefore a key marker of the extent to which the health practices in prison settings equate with those of the NHS. The research reported here considers the influences on medication management during the early stages of custody and the impact it has on prisoners. The study employed a qualitative design incorporating semi-structured interviews with 39 prisoners and 71 staff at 4 prisons. Participant observation was carried out in key internal prison locations relevant to the management of vulnerable prisoners to support and inform the interview process. Thematic analysis of the interview data and interpretation of the observational field-notes were undertaken manually. Emergent themes included the impact that delays, changes to or the removal of medication have on prisoners on entry to prison, and the reasons that such events take place. Inmates accounts suggested that psychotropic medication was found a key and valued form of support for people with mental health problems entering custody. Existing regimes of medication and the autonomy to self-medicate established in the community are disrupted and curtailed by the dominant practices and prison routines for the taking of prescribed medication. The continuity of mental health care is undermined by the removal or alteration of existing medication practice and changes on entry to prison which exacerbate prisoners' anxiety and sense of helplessness. Prisoners with a dual diagnosis are likely to be doubly vulnerable because of inconsistencies in substance

  4. Medication management and practices in prison for people with mental health problems: a qualitative study

    Directory of Open Access Journals (Sweden)

    Rogers Anne

    2009-10-01

    Full Text Available Abstract Background Common mental health problems are prevalent in prison and the quality of prison health care provision for prisoners with mental health problems has been a focus of critical scrutiny. Currently, health policy aims to align and integrate prison health services and practices with those of the National Health Service (NHS. Medication management is a key aspect of treatment for patients with a mental health problem. The medication practices of patients and staff are therefore a key marker of the extent to which the health practices in prison settings equate with those of the NHS. The research reported here considers the influences on medication management during the early stages of custody and the impact it has on prisoners. Methods The study employed a qualitative design incorporating semi-structured interviews with 39 prisoners and 71 staff at 4 prisons. Participant observation was carried out in key internal prison locations relevant to the management of vulnerable prisoners to support and inform the interview process. Thematic analysis of the interview data and interpretation of the observational field-notes were undertaken manually. Emergent themes included the impact that delays, changes to or the removal of medication have on prisoners on entry to prison, and the reasons that such events take place. Results and Discussion Inmates accounts suggested that psychotropic medication was found a key and valued form of support for people with mental health problems entering custody. Existing regimes of medication and the autonomy to self-medicate established in the community are disrupted and curtailed by the dominant practices and prison routines for the taking of prescribed medication. The continuity of mental health care is undermined by the removal or alteration of existing medication practice and changes on entry to prison which exacerbate prisoners' anxiety and sense of helplessness. Prisoners with a dual diagnosis are likely

  5. Excel 2013 for biological and life sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach biological and life sciences statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical science problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Each chapter explains statistical formulas and directs the reader to use Excel commands to solve specific, easy-to-understand science problemsPractice problems are provided at the end of each chapter with their solutions in an appendix.  Separately, there is a full Practice Test (with answers in an Appendix) that allows readers to test what they have learned.  Includes 164 illustrations in color Suitable for undergraduates or graduate student Prof. Tom Quirk is currently a Professor of Marketing at The Walker School of Business and Technology at Webster University in St....

  6. Citizenship as practice: Handling communication problems in encounters between persons with dementia and social workers.

    Science.gov (United States)

    Jh, Österholm; L-C, Hydén

    2016-11-01

    The overall aim of the study was to investigate if and how persons with dementia were able to take part in negotiations for formal support, as cases of citizenship as practice The transcripts used for analysis were from 11 assessment meetings conducted in Sweden, in which the formal applicant was a person with dementia. The findings suggest that the actual participation of persons with dementia in assessment meetings varies. Communication problems were found in the meetings to different degrees and were dealt with differently and with various consequences. For those persons with dementia contributing at the same levels as the other participants, there was an attempt at mutual understanding. For those making fewer contributions, the other interlocutors took over the initiative and thus affected the practice of citizenship by persons with dementia in a negative way. The practice of citizenship is situation based and varies depending on all participants. When the person with dementia is able to participate in the conversation, social workers can facilitate for them to overcome communication problems by giving them more time and signaling acceptance. If the person with dementia has great problems in participating, the other participants can find different strategies to at least involve her or him in the conversation. © The Author(s) 2014.

  7. Integral and differential methods for the numerical solution of 2-D field problems in high energy physics magnets and electrical machines

    International Nuclear Information System (INIS)

    Hannalla, A.Y.; Simkin, J.; Trowbridge, C.W.

    1979-10-01

    Numerical calculations of electromagnetic fields have been performed by solving integral or differential equations. Integral methods are ideally suited to open boundary problems and on the other hand the geometric complexity of electrical machines makes differential methods more attractive. In this paper both integral and differential equation methods are reviewed, and the limitations of the methods are highlighted, in an attempt to show how to select the best method for a particular problem. (author)

  8. Fuzzy pictures as philosophical problem and scientific practice a study of visual vagueness

    CERN Document Server

    Cat, Jordi

    2017-01-01

    This book presents a comprehensive discussion on the characterization of vagueness in pictures. It reports on how the problem of representation of images has been approached in scientific practice, highlighting the role of mathematical methods and the philosophical background relevant for issues such as representation, categorization and reasoning. Without delving too much into the technical details, the book examines and defends different kinds of values of fuzziness based on a complex approach to categorization as a practice, adopting conceptual and empirical suggestions from different fields including the arts. It subsequently advances criticisms and provides suggestions for interpretation and application. By describing a cognitive framework based on fuzzy, rough and near sets, and discussing all of the relevant mathematical and philosophical theories for the representation and processing of vagueness in images, the book offers a practice-oriented guide to fuzzy visual reasoning, along with novel insights ...

  9. Creative Problem Solving and Social Cooperation of Effective Physical Therapy Practice: A Pioneer Study and Overview

    Directory of Open Access Journals (Sweden)

    Eli Carmeli

    2003-01-01

    Full Text Available Action research (AR has an important role to play in educating physical therapists. Increasing efforts should be encouraged to instigate AR programs in physical therapy practice and clinical education. Such programs commonly require considerable effort and understanding by clinical instructors, and require adoption of new educational methods. AR programs can lead physical therapists and clinicians to be more questioning and reflective in evaluating practical questions regarding patient therapy and education. The purpose of this article is to educate the readers on the importance of AR and to provide a few relevant references on that topic. A specific study is described in this paper in which physical therapy clinical instructors participated in a structured workshop designed to demonstrate the values of AR and how such values can be incorporated in teaching their students. AR can lead to improved therapist-patient interaction and help solve specific practical problems arising during therapy sessions.

  10. Excel 2016 in applied statistics for high school students a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2018-01-01

    This textbook is a step-by-step guide for high school, community college, or undergraduate students who are taking a course in applied statistics and wish to learn how to use Excel to solve statistical problems. All of the statistics problems in this book will come from the following fields of study: business, education, psychology, marketing, engineering and advertising. Students will learn how to perform key statistical tests in Excel without being overwhelmed by statistical theory. Each chapter briefly explains a topic and then demonstrates how to use Excel commands and formulas to solve specific statistics problems. This book gives practice in using Excel in two different ways: (1) writing formulas (e.g., confidence interval about the mean, one-group t-test, two-group t-test, correlation) and (2) using Excel’s drop-down formula menus (e.g., simple linear regression, multiple correlations and multiple regression, and one-way ANOVA). Three practice problems are provided at the end of each chapter, along w...

  11. Current ethical and other problems in the practice of African traditional medicine.

    Science.gov (United States)

    Omonzejele, Peter

    2003-01-01

    Medicine in Africa is regarded as possessing its own "life force", not just using a system of prescribing. This is because health problems are not only attributed to pathological explanations alone, but also to other "forces". Hence, traditional healers utter incantations to take care of negative forces which militate against achieving cure. Treatment in African traditional medicine (ATM) is holistic. It seeks to strike a balance between the patients' body, soul and spirit. The problems arise from the infiltration of charlatans into the field, the practice of using mystical explanations for ill-health, and inadequate knowledge of the properties and clinical use of herbal remedies. Despite its problems, ATM can work in parallel with orthodox medicine using its strengths rather than its weaknesses. ATM has to be applied within a uniform ethical system. Practitioners of ATM must follow the principles of autonomy and confidentiality.

  12. An innovative artificial bee colony algorithm and its application to a practical intercell scheduling problem

    Science.gov (United States)

    Li, Dongni; Guo, Rongtao; Zhan, Rongxin; Yin, Yong

    2018-06-01

    In this article, an innovative artificial bee colony (IABC) algorithm is proposed, which incorporates two mechanisms. On the one hand, to provide the evolutionary process with a higher starting level, genetic programming (GP) is used to generate heuristic rules by exploiting the elements that constitute the problem. On the other hand, to achieve a better balance between exploration and exploitation, a leading mechanism is proposed to attract individuals towards a promising region. To evaluate the performance of IABC in solving practical and complex problems, it is applied to the intercell scheduling problem with limited transportation capacity. It is observed that the GP-generated rules incorporate the elements of the most competing human-designed rules, and they are more effective than the human-designed ones. Regarding the leading mechanism, the strategies of the ageing leader and multiple challengers make the algorithm less likely to be trapped in local optima.

  13. Numerical linear algebra with applications using Matlab

    CERN Document Server

    Ford, William

    2014-01-01

    Designed for those who want to gain a practical knowledge of modern computational techniques for the numerical solution of linear algebra problems, Numerical Linear Algebra with Applications contains all the material necessary for a first year graduate or advanced undergraduate course on numerical linear algebra with numerous applications to engineering and science. With a unified presentation of computation, basic algorithm analysis, and numerical methods to compute solutions, this book is ideal for solving real-world problems. It provides necessary mathematical background information for

  14. Hindi Numerals.

    Science.gov (United States)

    Bright, William

    In most languages encountered by linguists, the numerals, considered as a paradigmatic set, constitute a morpho-syntactic problem of only moderate complexity. The Indo-Aryan language family of North India, however, presents a curious contrast. The relatively regular numeral system of Sanskrit, as it has developed historically into the modern…

  15. Numerical scheme for optimization of xenon transient processes in a reactor. Problem on fast response without a limitation for phase variables

    International Nuclear Information System (INIS)

    Gerasimov, A.S.

    1975-01-01

    A numerical diagram is suggested of minimizing a period of xenon transient process in the reactor without any limitation of xenon-135 concentration. The problem is solved with a computer in a point model. Pontryagin's maximum principle is used so as to check optimization of the transient process

  16. Cognitive Skills Used to Solve Mathematical Word Problems and Numerical Operations: A Study of 6- to 7-Year-Old Children

    Science.gov (United States)

    Bjork, Isabel Maria; Bowyer-Crane, Claudine

    2013-01-01

    This study investigates the relationship between skills that underpin mathematical word problems and those that underpin numerical operations, such as addition, subtraction, division and multiplication. Sixty children aged 6-7 years were tested on measures of mathematical ability, reading accuracy, reading comprehension, verbal intelligence and…

  17. Attitude and practice of physical activity and social problem-solving ability among university students.

    Science.gov (United States)

    Sone, Toshimasa; Kawachi, Yousuke; Abe, Chihiro; Otomo, Yuki; Sung, Yul-Wan; Ogawa, Seiji

    2017-04-04

    Effective social problem-solving abilities can contribute to decreased risk of poor mental health. In addition, physical activity has a favorable effect on mental health. These previous studies suggest that physical activity and social problem-solving ability can interact by helping to sustain mental health. The present study aimed to determine the association between attitude and practice of physical activity and social problem-solving ability among university students. Information on physical activity and social problem-solving was collected using a self-administered questionnaire. We analyzed data from 185 students who participated in the questionnaire surveys and psychological tests. Social problem-solving as measured by the Social Problem-Solving Inventory-Revised (SPSI-R) (median score 10.85) was the dependent variable. Multiple logistic regression analysis was employed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for higher SPSI-R according to physical activity categories. The multiple logistic regression analysis indicated that the ORs (95% CI) in reference to participants who said they never considered exercising were 2.08 (0.69-6.93), 1.62 (0.55-5.26), 2.78 (0.86-9.77), and 6.23 (1.81-23.97) for participants who did not exercise but intended to start, tried to exercise but did not, exercised but not regularly, and exercised regularly, respectively. This finding suggested that positive linear association between physical activity and social problem-solving ability (p value for linear trend social problem-solving ability.

  18. Employees with mental health problems: Survey of U.K. employers' knowledge, attitudes and workplace practices.

    Science.gov (United States)

    Brohan, Elaine; Henderson, Claire; Little, Kirsty; Thornicroft, Graham

    2010-01-01

    To investigate whether employers who have experience of hiring people with mental health problems differ significantly from those without such experience in terms of knowledge, attitudes and behaviours regarding mental health in the workplace, and the concerns which they report about employing people with mental health problems. We also examine whether non-workplace social contact is associated with the above variables. A telephone survey was conducted with a randomly selected sample of British employers. The sample included a similar number of human resource managers and managers/executive employees in other roles. 502 employers took part. Having employed someone with a mental health problem was associated with closer non-workplace social contact. Those with experience of employing applicants with mental health problems had significant differences in knowledge (regarding the law), and behaviour (having a policy on hiring applicants with disabilities) but not in attitudes. Non-workplace social contact may be useful to consider in understanding hiring practices. The nature of social contact at work and possible lack of impact of this contact on employer attitudes and concerns warrants further study. Greater support is needed for employers to understand the law regarding mental health problems in the workplace.

  19. Developing critical reflection for professional practice through problem-based learning.

    Science.gov (United States)

    Williams, B

    2001-04-01

    To explore the influence of current learning traditions in nursing on the development of reflection and critical reflection as professional practice skills and to offer suggestions for nursing education that will specifically facilitate the development of critical reflection. ORGANIZATIONAL CONSTRUCTS: Mezirow's transformative learning theory, Barrows conceptualization of problem-based learning (PBL). Integrative literature review of published literature related to nursing, health science education and professional education from 1983-2000. Professional education scholars concur that specialized knowledge is clearly essential for professional practice, however, they also suggest that self-consciousness (reflection) and continual self-critique (critical reflection) are crucial to continued competence. While strategies to facilitate reflection have been outlined in the literature, specific strategies to facilitate the development of critical reflection and implications for nursing education are much less clear. Advocates of reflective and critically reflective practice suggest that the development of these abilities should be inextricably linked to professional development and can be developed through active repeated guided practice. In health care, PBL based on constructivism, has been identified as one way to facilitate the development of these skills. Nursing learners exposed to PBL develop the ability to be reflective and critically reflective in their learning and acquire the knowledge and skill within the discipline of nursing by encountering key professional practice situations as the stimulus and focus of their classroom learning. The learners' ability to be both reflective and critically reflective in their learning is developed by critical questioning of the faculty tutor during situational analysis, learning need determination, application of knowledge, critique of resources and personal problem-solving processes, and summarization of what was learned.

  20. Still a difficult business? Negotiating alcohol-related problems in general practice consultations.

    Science.gov (United States)

    Rapley, Tim; May, Carl; Frances Kaner, Eileen

    2006-11-01

    This paper describes general practitioners' (GPs) experiences of detecting and managing alcohol and alcohol-related problems in consultations. We undertook qualitative research in two phases in the North-East of England. Initially, qualitative interviews with 29 GPs explored their everyday work with patients with alcohol-related issues. We then undertook group interviews--two with GPs and one with a primary care team--where they discussed and challenged findings of the interviews. The GPs reported routinely discussing alcohol with patients with a range of alcohol-related problems. GPs believed that this work is important, but felt that until patients were willing to accept that their alcohol consumption was problematic they could achieve very little. They tentatively introduced alcohol as a potential problem, re-introduced the topic periodically, and then waited until the patient decided to change their behaviour. They were aware that they could identify and manage more patients. A lack of time and having to work with the multiple problems that patients brought to consultations were the main factors that stopped GPs managing more risky drinkers. Centrally, we compared the results of our study with [Thom, B., & Tellez, C. (1986). A difficult business-Detecting and managing alcohol-problems in general-practice. British Journal of Addiction, 81, 405-418] seminal study that was undertaken 20 years ago. We show how the intellectual, moral, emotional and practical difficulties that GPs currently face are quite similar to those faced by GPs from 20 years ago. As the definition of what could constitute abnormal alcohol consumption has expanded, so the range of consultations that they may have to negotiate these difficulties in has also expanded.

  1. Robust numerical methods for boundary-layer equations for a model problem of flow over a symmetric curved surface

    NARCIS (Netherlands)

    A.R. Ansari; B. Hossain; B. Koren (Barry); G.I. Shishkin (Gregori)

    2007-01-01

    textabstractWe investigate the model problem of flow of a viscous incompressible fluid past a symmetric curved surface when the flow is parallel to its axis. This problem is known to exhibit boundary layers. Also the problem does not have solutions in closed form, it is modelled by boundary-layer

  2. Hypnosis in nursing practice--emphasis on the "problem patient' who has pain--Part II.

    Science.gov (United States)

    Zahourek, R P

    1982-04-01

    The program of treating burned patients with hypnosis was expanded to treating multi-problem and chronic pain patients on the same surgical unit at Denver General Hospital. The majority of patients received some benefit. Many gained control over intense pain and many increased their sense of self-esteem and mastery. The behavioral problems diminished and the staff became reinterested and reinvolved with these very needy people. Whether or not nurses elect to practice hypnosis, the principles are familiar and can be added to the repertory of nursing practice. Physical and psychological relaxation relieves distress and potentiates patients' comfort with or without pain medication. Communicate to the patient that what you are doing builds confidence and increases the probability that treatment wil be effective. Furthermore, recognizing imaginary capacities as powerful in promoting comfort adds an option for intervention not always considered or used by nurses. Whether or not nurses describe what they do as "hypnosis," the use of these techniques can be useful to their practice and to the patients in whom they attempt to alleviate suffering and promote comfort and growth.

  3. Numerical determination of families of three-dimensional double-symmetric periodic orbits in the restricted three-body problem. Pt. 1

    International Nuclear Information System (INIS)

    Kazantzis, P.G.

    1979-01-01

    New families of three-dimensional double-symmetric periodic orbits are determined numerically in the Sun-Jupiter case of the restricted three-body problem. These families bifurcate from the 'vertical-critical' orbits (αsub(ν) = -1, csub(ν) = 0) of the 'basic' plane families i. g 1 g 2 h, a, m and I. Further the numerical procedure employed in the determination of these families has been described and interesting results have been pointed out. Also, computer plots of the orbits of these families have been shown in conical projections. (orig.)

  4. Computer-assisted mammography in clinical practice: Another set of problems to solve

    International Nuclear Information System (INIS)

    Gale, A.G.; Roebuck, E.J.; Worthington, B.S.

    1986-01-01

    To be adopted in radiological practice, computer-assisted diagnosis must address a domain of realistic complexity and have a high performance in terms of speed and reliability. Use of a microcomputer-based system of mammographic diagnoses employing discriminant function analysis resulted in significantly fewer false-positive diagnoses while producing a similar level of correct diagnoses of cancer as normal reporting. Although such a system is a valuable teaching aid, its clinical use is constrained by the problems of unambiguously codifying descriptors, data entry time, and the tendency of radiologists to override predicted diagnoses which conflict with their own

  5. [Application of problem-based learning in teaching practice of Science of Meridians and Acupoints].

    Science.gov (United States)

    Wang, Xiaoyan; Tang, Jiqin; Ying, Zhenhao; Zhang, Yongchen

    2015-02-01

    Science of Meridians and Acupoints is the bridge between basic medicine and clinical medicine of acupuncture and moxibustion. This teaching practice was conducted in reference to the teaching mode of problembased learning (PBL), in association with the clinical design problems, by taking as the students as the role and guided by teachers. In order to stimulate students' active learning enthusiasm, the writers implemented the class teaching in views of the typical questions of clinical design, presentation of study group, emphasis on drawing meridian running courses and acupoint locations, summarization and analysis, as well as comprehensive evaluation so that the comprehensive innovative ability of students and the teaching quality could be improved.

  6. Excel 2007 for Business Statistics A Guide to Solving Practical Business Problems

    CERN Document Server

    Quirk, Thomas J

    2012-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach business statistics effectively. It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical business problems. If understanding statistics isn't your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in business courses. Its powerful computat

  7. FEW PRACTICAL ASPECTS AND PROBLEMS REGARDING LAW NR. 202/2010

    Directory of Open Access Journals (Sweden)

    ALEXANDRA CRISTINA JIPA

    2011-04-01

    Full Text Available We have analyzed the impact the introduction of art. 74¹ penal C. over a certain category of infractions, respectively over the economical nature infractions. Harmonization of such recent norms with the already existent legislative framework rises a series of questions and possible practical problems. Also, we have considered interesting to appreciate if such changes are sufficient or there is not a conflict between the punishments set forth by regulators for each of such infractions. Should the answer be yes, there should be considered the possible conciliation methods.

  8. Practical solutions for multi-objective optimization: An application to system reliability design problems

    International Nuclear Information System (INIS)

    Taboada, Heidi A.; Baheranwala, Fatema; Coit, David W.; Wattanapongsakorn, Naruemon

    2007-01-01

    For multiple-objective optimization problems, a common solution methodology is to determine a Pareto optimal set. Unfortunately, these sets are often large and can become difficult to comprehend and consider. Two methods are presented as practical approaches to reduce the size of the Pareto optimal set for multiple-objective system reliability design problems. The first method is a pseudo-ranking scheme that helps the decision maker select solutions that reflect his/her objective function priorities. In the second approach, we used data mining clustering techniques to group the data by using the k-means algorithm to find clusters of similar solutions. This provides the decision maker with just k general solutions to choose from. With this second method, from the clustered Pareto optimal set, we attempted to find solutions which are likely to be more relevant to the decision maker. These are solutions where a small improvement in one objective would lead to a large deterioration in at least one other objective. To demonstrate how these methods work, the well-known redundancy allocation problem was solved as a multiple objective problem by using the NSGA genetic algorithm to initially find the Pareto optimal solutions, and then, the two proposed methods are applied to prune the Pareto set

  9. Knowledge and reported practice of antibiotic prescription by dentists for common oral problems

    International Nuclear Information System (INIS)

    Tanwir, F.; Marrone, G.; Lundborg, C. S.

    2013-01-01

    Objective: To assess the knowledge and reported practice in relation to antibiotic prescribing regarding common oral problems by dentists in Karachi, Pakistan. Study Design: Cross-sectional survey. Place and Duration of Study: Three Dental Colleges of Karachi, from July to December 2010. Methodology: The cross-sectional study was conducted in Karachi, Pakistan in the Outpatient Departments (OPD) of three dental colleges. Inclusion criteria were full time employed dentists working in their respective OPDs (n = 100). The dentists were asked to fill a questionnaire. The questionnaire included (i) general information, (ii) perception and knowledge of antibiotic resistance, (iii) reported management of oral problems, (iv) perceptions about oral infections and (v) perceptions of how people perceive oral problems. To assess dentist's ability to relate knowledge to practice regarding the management of the most common oral problems, written simulated case scenarios with related questions were also included. Scores were given for each correct answer. Results: The response rate was 85%. Of the total respondents, 65 (76%) were under the age of 30 years, 53 (62%) were males and 32 (38%) females. Out of 85 respondents 53% (n = 45) reported prescribing of antibiotics 4 - 5 times a week, 87% (n = 74) prescribe antibiotics based upon symptoms and 64% (n = 54) prescribed antibiotics in abscess condition. The total score for all four scenarios showed that nearly two thirds (61%) of all respondents scored sub-optimally. Conclusion: A substantial number of dentists had suboptimal knowledge regarding antibiotic use. This might lead to the provision of suboptimal care of patients with dental infections. Therefore, continuing education, training and supervision are recommended to improve the quality of dental management. (author)

  10. Curriculum providing cognitive knowledge and problem-solving skills for anesthesia systems-based practice.

    Science.gov (United States)

    Wachtel, Ruth E; Dexter, Franklin

    2010-12-01

    Residency programs accredited by the ACGME are required to teach core competencies, including systems-based practice (SBP). Projects are important for satisfying this competency, but the level of knowledge and problem-solving skills required presupposes a basic understanding of the field. The responsibilities of anesthesiologists include the coordination of patient flow in the surgical suite. Familiarity with this topic is crucial for many improvement projects. A course in operations research for surgical services was originally developed for hospital administration students. It satisfies 2 of the Institute of Medicine's core competencies for health professionals: evidence-based practice and work in interdisciplinary teams. The course lasts 3.5 days (eg, 2 weekends) and consists of 45 cognitive objectives taught using 7 published articles, 10 lectures, and 156 computer-assisted problem-solving exercises based on 17 case studies. We tested the hypothesis that the cognitive objectives of the curriculum provide the knowledge and problem-solving skills necessary to perform projects that satisfy the SBP competency. Standardized terminology was used to define each component of the SBP competency for the minimum level of knowledge needed. The 8 components of the competency were examined independently. Most cognitive objectives contributed to at least 4 of the 8 core components of the SBP competency. Each component of SBP is addressed at the minimum requirement level of exemplify by at least 6 objectives. There is at least 1 cognitive objective at the level of summarize for each SBP component. A curriculum in operating room management can provide the knowledge and problem-solving skills anesthesiologists need for participation in projects that satisfy the SBP competency.

  11. A stable high-order perturbation of surfaces method for numerical simulation of diffraction problems in triply layered media

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Youngjoon, E-mail: hongy@uic.edu; Nicholls, David P., E-mail: davidn@uic.edu

    2017-02-01

    The accurate numerical simulation of linear waves interacting with periodic layered media is a crucial capability in engineering applications. In this contribution we study the stable and high-order accurate numerical simulation of the interaction of linear, time-harmonic waves with a periodic, triply layered medium with irregular interfaces. In contrast with volumetric approaches, High-Order Perturbation of Surfaces (HOPS) algorithms are inexpensive interfacial methods which rapidly and recursively estimate scattering returns by perturbation of the interface shape. In comparison with Boundary Integral/Element Methods, the stable HOPS algorithm we describe here does not require specialized quadrature rules, periodization strategies, or the solution of dense non-symmetric positive definite linear systems. In addition, the algorithm is provably stable as opposed to other classical HOPS approaches. With numerical experiments we show the remarkable efficiency, fidelity, and accuracy one can achieve with an implementation of this algorithm.

  12. The Science Shop for Physics: an interface between practical problems in society and physical knowledge

    Science.gov (United States)

    van den Berg, G. P.

    1998-03-01

    Since some 20 years most Dutch universities have one or more science shops. Central shops handle research questions for all disciplines. Specialized shops are part of a department of chemistry or medicine, history, social science, etc. The shops have evolved rather differently, but their main mission still is to help social groups that lack money and have no easy access to scientific knowledge, e.g. neighbourhood, environmental, third world or patient groups. Most also help non-commercial organizations such as schools, trade unions or local authorities. Low-cost help can be provided because students do the work as part of their training, mainly in student projects (literature search, practical work, graduation, etc.). A total staff of 80, helped by 600 students, 250 voluntary and 50 paid researchers, handle 1500 questions resulting in 300 reports (estimated figures 1995). Science shops for physics (`Physics Shop', PS) have to deal with practical problems, generally involving classical physics. Major topics are noise, vibration, radiation, indoor climate and energy: most of the work lies in estimating/measuring relevant parameters, assessing impact, seeking solutions. The 3 Dutch PS's have developed in different directions. One is run entirely by students and deals with small, concrete problems. The second PS is managed by a co-ordinator who mediates between client groups and physics staff members who assist students in small and larger projects. The third has a lot of in-house expertise, and the shop staff is in direct contact with client groups as well as students who work in the PS itself. In questions submitted to the PS it is not always immediately clear what to do or how to do it because of the non-scientific phrasing of the problems and problems include non-physical (e.g. technical, health or legal) aspects. Also, difficulties in solving the problems are typically not in the underlying physics, but in the lack of accurate data and of control of the complex

  13. A set of numerical meteorological models for solving basic and some special problems in the Boris Kidric Institute

    International Nuclear Information System (INIS)

    Grscic, Z.

    1989-01-01

    Models for solving transport and dispersion problems of radioactive pollutants through atmosphere are briefly shown. These models are the base for solving and some special problems such as: estimating effective and physical heights of radioactive sources, computation of radioactive concentration distribution from multiple sources etc (author)

  14. Turkish EFL Academicians' Problems Concerning Translation Activities and Practices, Attitudes towards the Use of Online and Printed Translation Tools, and Suggestions for Quality Translation Practice

    Science.gov (United States)

    Zengin, Bugra; Kacar, Isil Gunseli

    2011-01-01

    This mixed method research study aimed to highlight the problems of EFL academicians concerning their current translation practices, their attitudes towards the use of various translation tools, and offer suggestions for more quality translation practices. Seventy-three EFL academicians from three Turkish universities participated in the study.…

  15. Excel 2010 for environmental sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach environmental sciences statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical environmental sciences problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in environmental science courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2010 for Environmental Sciences Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Eac...

  16. A statistical examination of the practical problems of measurement in accountancy tanks

    International Nuclear Information System (INIS)

    Davies, W.; Good, P.T.; Hamlin, A.G.

    1979-01-01

    In the first part of the paper the general problems of measurement in large accountancy tanks are considered. The generalized tank is assumed to have an extended geometry for the avoidance of criticality, to be fitted with pneumatic level indicating devices and with temperature sensors, and to contain liquid to be accounted, such as that derived from irradiated fuel elements, which is sufficiently active to generate appreciable heat and also radiolytic gases. Possible uncertainties contributed to the final measurement of fissile material contained in or discharged from the tank by the effects of hydrostatic heads, temperature, radiolysis, surface tension, and drainage are considered in detail. The magnitude of these is established from practical data and the errors combined in order to estimate the best possible performance, which, under the specified conditions, appears to be about +-0.3% (1 sigma). The implications for the design of large accountancy tanks are considered, with particular reference to the design of accountancy tanks for future plants where the above precision may not be adequate. The second part of the paper considers practical approaches to the problem of ensuring that actual performance of the measuring system approaches the best possible as closely as possible. In particular, a system of operation in which the accountancy tank is utilized essentially as a fixed volume, with the measuring systems restricted to determining small variations from this nominal volume, offers considerable promise

  17. Excel 2013 for social sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach social science statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical social science problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in social science courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2013 for Social Science Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each chapter explains statistical formul...

  18. Excel 2013 for engineering statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach engineering statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical engineering problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in engineering courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2013 for Engineering Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs...

  19. Excel 2013 for environmental sciences statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J; Horton, Howard F

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach environmentall sciences statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical environmental science problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in environmental science courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2013 for Environmental Sciences Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each chap...

  20. Excel 2010 for human resource management statistics a guide to solving practical problems

    CERN Document Server

    Quirk, Thomas J

    2014-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach human resource  management statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical human resource management problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in human resource management courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2010 for Human Resource Management Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and ...

  1. Excel 2013 for business statistics a guide to solving practical business problems

    CERN Document Server

    Quirk, Thomas J

    2015-01-01

    This is the first book to show the capabilities of Microsoft Excel to teach business statistics effectively.  It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical business problems.  If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you.  Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in business courses.  Its powerful computational ability and graphical functions make learning statistics much easier than in years past.  However, Excel 2013 for Business Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work.                                �...

  2. Broadening participation in community problem solving: a multidisciplinary model to support collaborative practice and research.

    Science.gov (United States)

    Lasker, Roz D; Weiss, Elisa S

    2003-03-01

    Over the last 40 years, thousands of communities-in the United States and internationally-have been working to broaden the involvement of people and organizations in addressing community-level problems related to health and other areas. Yet, in spite of this experience, many communities are having substantial difficulty achieving their collaborative objective, and many funders of community partnerships and participation initiatives are looking for ways to get more out of their investment. One of the reasons we are in this predicament is that the practitioners and researchers who are interested in community collaboration come from a variety of contexts, initiatives, and academic disciplines, and few of them have integrated their work with experiences or literatures beyond their own domain. In this article, we seek to overcome some of this fragmentation of effort by presenting a multidisciplinary model that lays out the pathways by which broadly participatory processes lead to more effective community problem solving and to improvements in community health. The model, which builds on a broad array of practical experience as well as conceptual and empirical work in multiple fields, is an outgrowth of a joint-learning work group that was organized to support nine communities in the Turning Point initiative. Following a detailed explication of the model, the article focuses on the implications of the model for research, practice, and policy. It describes how the model can help researchers answer the fundamental effectiveness and "how-to" questions related to community collaboration. In addition, the article explores differences between the model and current practice, suggesting strategies that can help the participants in, and funders of, community collaborations strengthen their efforts.

  3. Being relevant: Practical guidance for early career researchers interested in solving conservation problems

    Directory of Open Access Journals (Sweden)

    J.M. Chapman

    2015-07-01

    Full Text Available In a human-altered world where biodiversity is in decline and conservation problems abound, there is a dire need to ensure that the next generation of conservation scientists have the knowledge, skills, and training to address these problems. So called “early career researchers” (ECRs in conservation science have many challenges before them and it is clear that the status quo must change to bridge the knowledge–action divide. Here we identify thirteen practical strategies that ECRs can employ to become more relevant. In this context, “relevance” refers to the ability to contribute to solving conservation problems through engagement with practitioners, policy makers, and stakeholders. Conservation and career strategies outlined in this article include the following: thinking ‘big picture’ during conservation projects; embracing various forms of knowledge; maintaining positive relationships with locals familiar with the conservation issue; accepting failure as a viable (and potentially valuable outcome; daring to be creative; embracing citizen science; incorporating interdisciplinarity; promoting and practicing pro-environmental behaviours; understanding financial aspects of conservation; forming collaboration from the onset of a project; accepting the limits of technology; ongoing and effective networking; and finally, maintaining a positive outlook by focusing on and sharing conservation success stories. These strategies move beyond the generic and highlight the importance of continuing to have an open mind throughout the entire conservation process, from establishing one’s self as an asset to embracing collaboration and interdisciplinary work, and striving to push for professional and personal connections that strengthen personal career objectives.

  4. Diagnostic practice and its impacts on parental health and child behaviour problems in autism spectrum disorders.

    Science.gov (United States)

    Reed, Phil; Osborne, Lisa A

    2012-10-01

    Obtaining a diagnosis is a key point in developing a treatment plan for children with autism spectrum disorders (ASD), but little attention has been paid to the impacts of diagnostic practices on families, and the consequent impact on child outcomes. Parents' experiences during ASD diagnosis for their child can be stressful, and such stress can lead to parental ill health, child-behaviour problems, and poorer child outcomes following treatment. Thus, the conduct of diagnosis may be of particular importance for subsequent child outcomes and parental health. A lack of knowledge regarding best diagnostic practice may ultimately impair treatment efficacy and lead to increased health- and economic-burdens. Given this, the current article examines recent work concerning: parental experiences of ASD diagnoses; general health and psychological functioning of parents of newly-diagnosed children with ASD; aspects of the diagnostic process impacting on parental functioning; and the relationship of parental functioning to child outcomes. These are placed into the context of diagnostic best practice for ASD, and understanding the complex relationship between ASD and family variables.

  5. Information management problems relating to numeric data base services for DOE. QEI report 9413 (Interim report for Phase II of QEI project 4191)

    International Nuclear Information System (INIS)

    Kuipers, J.W.; Thorpe, R.W.

    1979-01-01

    Problems of numeric data are examined as these relate to the question of possible steps toward implementation of an integrated national information system for DOE. It is proposed that DOE make policy and organization changes in order to centralize and upgrade information management as a particular responsibility for the oversight of DOE-wide information requirements. Eight points to be emphasized in such a program are set forth

  6. Some properties of band matrix and its application to the numerical solution one-dimensional Bratu's problem

    Directory of Open Access Journals (Sweden)

    Reza Jalilian

    2014-07-01

    Full Text Available ‎A Class of new methods based on a septic non-polynomial spline‎‎function for the numerical solution one-dimensional Bratu's problem‎are presented‎. ‎The local truncation errors and the methods of order‎‎2th‎, ‎4th‎, ‎6th‎, ‎8th‎, ‎10th‎, ‎and 12th‎, ‎are obtained‎. ‎The inverse of‎some band matrixes are obtained which are required in provingthe‎ convergence analysis of the presented method‎. ‎Associatedboundary‎ formulas are developed‎. ‎Convergence analysis of thesemethods is‎ discussed‎. ‎Numerical results are given to illustrate theefficiency‎ of methods‎.

  7. Polynomial chaos methods for hyperbolic partial differential equations numerical techniques for fluid dynamics problems in the presence of uncertainties

    CERN Document Server

    Pettersson, Mass Per; Nordström, Jan

    2015-01-01

    This monograph presents computational techniques and numerical analysis to study conservation laws under uncertainty using the stochastic Galerkin formulation. With the continual growth of computer power, these methods are becoming increasingly popular as an alternative to more classical sampling-based techniques. The approach described in the text takes advantage of stochastic Galerkin projections applied to the original conservation laws to produce a large system of modified partial differential equations, the solutions to which directly provide a full statistical characterization of the effect of uncertainties. Polynomial Chaos Methods of Hyperbolic Partial Differential Equations focuses on the analysis of stochastic Galerkin systems obtained for linear and non-linear convection-diffusion equations and for a systems of conservation laws; a detailed well-posedness and accuracy analysis is presented to enable the design of robust and stable numerical methods. The exposition is restricted to one spatial dime...

  8. International Conference on Hyperbolic Problems Theory, Numerics, Applications Held in Stony Brook, New York on 13-17 June 1994

    Science.gov (United States)

    1994-07-25

    Astrophysik are investigated numerically. These collisions do not seem to Karl - Schwarzschild -str., 1, D-85470 Garching, Germany be elastic. On the other hand...Astrophysak, Departamento de Matemdtsca Aplscada y Astronomia Karl -Schwaarzschild-Str. i Universadad de Valencia 85740 Garching bes Munchen. Germany "E...the R-W metric to the empty space Schwarzschild metric, and since in this cae mass and momentum cannot cross the interface, (which in this case models

  9. Numerical analysis

    CERN Document Server

    Rao, G Shanker

    2006-01-01

    About the Book: This book provides an introduction to Numerical Analysis for the students of Mathematics and Engineering. The book is designed in accordance with the common core syllabus of Numerical Analysis of Universities of Andhra Pradesh and also the syllabus prescribed in most of the Indian Universities. Salient features: Approximate and Numerical Solutions of Algebraic and Transcendental Equation Interpolation of Functions Numerical Differentiation and Integration and Numerical Solution of Ordinary Differential Equations The last three chapters deal with Curve Fitting, Eigen Values and Eigen Vectors of a Matrix and Regression Analysis. Each chapter is supplemented with a number of worked-out examples as well as number of problems to be solved by the students. This would help in the better understanding of the subject. Contents: Errors Solution of Algebraic and Transcendental Equations Finite Differences Interpolation with Equal Intervals Interpolation with Unequal Int...

  10. Theory and applications of numerical analysis

    CERN Document Server

    Phillips, G M

    1996-01-01

    This text is a self-contained Second Edition, providing an introductory account of the main topics in numerical analysis. The book emphasizes both the theorems which show the underlying rigorous mathematics andthe algorithms which define precisely how to program the numerical methods. Both theoretical and practical examples are included.* a unique blend of theory and applications* two brand new chapters on eigenvalues and splines* inclusion of formal algorithms* numerous fully worked examples* a large number of problems, many with solutions

  11. Numerical experiments using CHIEF to treat the nonuniqueness in solving acoustic axisymmetric exterior problems via boundary integral equations

    Directory of Open Access Journals (Sweden)

    Adel A.K. Mohsen

    2010-07-01

    Full Text Available The problem of nonuniqueness (NU of the solution of exterior acoustic problems via boundary integral equations is discussed in this article. The efficient implementation of the CHIEF (Combined Helmholtz Integral Equations Formulation method to axisymmetric problems is studied. Interior axial fields are used to indicate the solution error and to select proper CHIEF points. The procedure makes full use of LU-decomposition as well as the forward solution derived in the solution. Implementations of the procedure for hard spheres are presented. Accurate results are obtained up to a normalised radius of ka = 20.983, using only one CHIEF point. The radiation from a uniformly vibrating sphere is also considered. Accurate results for ka up to 16.927 are obtained using two CHIEF points.

  12. A family of four stages embedded explicit six-step methods with eliminated phase-lag and its derivatives for the numerical solution of the second order problems

    Science.gov (United States)

    Simos, T. E.

    2017-11-01

    A family of four stages high algebraic order embedded explicit six-step methods, for the numerical solution of second order initial or boundary-value problems with periodical and/or oscillating solutions, are studied in this paper. The free parameters of the new proposed methods are calculated solving the linear system of equations which is produced by requesting the vanishing of the phase-lag of the methods and the vanishing of the phase-lag's derivatives of the schemes. For the new obtained methods we investigate: • Its local truncation error (LTE) of the methods.• The asymptotic form of the LTE obtained using as model problem the radial Schrödinger equation.• The comparison of the asymptotic forms of LTEs for several methods of the same family. This comparison leads to conclusions on the efficiency of each method of the family.• The stability and the interval of periodicity of the obtained methods of the new family of embedded finite difference pairs.• The applications of the new obtained family of embedded finite difference pairs to the numerical solution of several second order problems like the radial Schrödinger equation, astronomical problems etc. The above applications lead to conclusion on the efficiency of the methods of the new family of embedded finite difference pairs.

  13. An Introduction to Optimal Control Problems in Life Sciences and Economics From Mathematical Models to Numerical Simulation with MATLAB®

    CERN Document Server

    Anita, Sebastian; Capasso, Vincenzo

    2011-01-01

    Combining control theory and modeling, this textbook introduces and builds on methods for simulating and tackling concrete problems in a variety of applied sciences. Emphasizing "learning by doing," the authors focus on examples and applications to real-world problems. An elementary presentation of advanced concepts, proofs to introduce new ideas, and carefully presented MATLAB(R) programs help foster an understanding of the basics, but also lead the way to new, independent research. With minimal prerequisites and exercises in each chapter, this work serves as an excellent textbook a

  14. Practical investigation of a monopod fabrication method and the numerical investigation of its up-righting process

    Directory of Open Access Journals (Sweden)

    Khaled A. Hafez

    2013-09-01

    Full Text Available The principal purpose of this paper is to present a novel two phases rational scenario applied in constructing an offshore monopod platform; in which the two phases are the all-ground horizontal construction phase and the post-construction phase. Concerning the all-ground construction phase, a brief investigation of its different stages, i.e., pre-fabrication, fabrication, pre-assembling, positioning, assembling, and surface finishing is introduced. The important practical aspects of such construction phase are investigated without going into the nitty-gritty of the details involved therein. Concerning the post-construction phase, a clear investigation of its sequential stages, i.e., lifting, moving and up-righting is introduced. A finite element model (FEM of the monopod platform is created to perform the structural analysis necessary to decide the suspension points/devices and the handling scenario during the various stages of the post-construction phase on a rational wise. Such structural analysis is performed within the framework of the three dimensional quasi-static modeling and analysis aiming at simulating the realistic handling condition, and hence introducing a reliable physical interpretation of the numerical results. For the whole effort to be demonstrated efficiently, the results obtained are analyzed, the conclusions are presented, and few related recommendations are suggested.

  15. [ACTUAL PROBLEMS OF HYGIENE SCIENCE AND PRACTICE IN THE PRESERVATION OF PUBLIC HEALTH].

    Science.gov (United States)

    Onishchenko, G G

    2015-01-01

    In the article there are designated the state and actual hygiene tasks on the issue of environmental pollution and its effects on health of the population. There was emphasized the growing importance of chemical contamination of various objects of environment--air water, soil, and living environment. There is presented the analysis of data on different types of treatment of municipal waste in selected countries. There were shown the significance of the developed Guidance on risk assessmentfor public health as a toolfor making sound management decisions, prospects of using of the methodology of epidemiological mapping based on geoinformational technology (GIS technology). There was marked an important role of the younger generation of hygienists and health officers in further work on both preservation and improvement the health of the population in their countries, harmonization of scientific and practical solutions of actual problems of hygiene.

  16. [Children of mentally ill parents. A study of problem awareness in clinical routine practice].

    Science.gov (United States)

    Bohus, M; Schehr, K; Berger-Sallawitz, F; Novelli-Fischer, U; Stieglitz, R D; Berger, M

    1998-05-01

    The risk of developing clinically relevant psychiatric disorders in the lifetime course is significantly greater among children of mentally ill parents. A child-adapted programme of information concerning the nature and symptomatology of parental illness is considered to be an important preventive factor, and lies within the domain of the psychiatrist's or therapist's responsibilities. During the developmental phase of a prevention project at Freiburg University's Department of Psychiatry and Psychotherapy, both clinical practice and the level of problem awareness among patients and the therapists were evaluated. Over a period of one year, consecutive interviews involving 114 patients with children under 18 years of age, as well as their respective therapists, were conducted. The results showed that: scarcely any exchanges between children and therapists took place; the extent to which children are informed about parental illness must be considered as small; a high percentage of such children are already evaluated by their parents as disturbed, and the pressing need for support exists.

  17. Socio-Demographic and Practice-Oriented Factors Related to Proficiency in Problem Solving: A Lifelong Learning Perspective

    Science.gov (United States)

    Desjardins, Richard; Ederer, Peer

    2015-01-01

    This article explores the relative importance of different socio-demographic and practice-oriented factors that are related to proficiency in problem solving in technology-rich environments (PSTREs) and by extension may be related to complex problem solving (CPS). The empirical analysis focuses on the proficiency measurements of PSTRE made…

  18. A Critical Discourse Analysis of Practical Problems in a Foundation Mathematics Course at a South African University

    Science.gov (United States)

    le Roux, Kate; Adler, Jill

    2016-01-01

    Mathematical problems that make links to the everyday and to disciplines other than mathematics--variously referred to as practical, realistic, real-world or applied problems in the literature--feature in school and undergraduate mathematics reforms aimed at increasing mathematics participation in contexts of inequity and diversity. In this…

  19. Numerical reconstruction of photon-number statistics from photocounting statistics: Regularization of an ill-posed problem

    International Nuclear Information System (INIS)

    Starkov, V. N.; Semenov, A. A.; Gomonay, H. V.

    2009-01-01

    We demonstrate a practical possibility of loss compensation in measured photocounting statistics in the presence of dark counts and background radiation noise. It is shown that satisfactory results are obtained even in the case of low detection efficiency and large experimental errors.

  20. Numerical linear algebra theory and applications

    CERN Document Server

    Beilina, Larisa; Karchevskii, Mikhail

    2017-01-01

    This book combines a solid theoretical background in linear algebra with practical algorithms for numerical solution of linear algebra problems. Developed from a number of courses taught repeatedly by the authors, the material covers topics like matrix algebra, theory for linear systems of equations, spectral theory, vector and matrix norms combined with main direct and iterative numerical methods, least squares problems, and eigen problems. Numerical algorithms illustrated by computer programs written in MATLAB® are also provided as supplementary material on SpringerLink to give the reader a better understanding of professional numerical software for the solution of real-life problems. Perfect for a one- or two-semester course on numerical linear algebra, matrix computation, and large sparse matrices, this text will interest students at the advanced undergraduate or graduate level.

  1. PROBLEMS IN VEGETATION MONITORING IN NATURE MANAGEMENT PRACTICE: TWO CASE STUDIES

    Directory of Open Access Journals (Sweden)

    I. DE RONDE

    2007-04-01

    Full Text Available One of the major requirements of the monitoring of vegetation is the comparability of data between years. Therefore, a proper sampling scheme is essential. However, through the years, in nature management practice lots of data collected without a primary monitoring goal. Afterwards, it often seems very valuable to include these older data in the analysis for several reasons. In two examples from military ranges in the Netherlands, two of the problems which can be met with in comparing unequivalent or biased data in monitoring are shown. In the first example, the frequency of grassland species in two sets of relevés is examined. A solution is presented for the overrepresentation of relevés from one or more vegetation types from the first year, based on the area of the vegetation types on the vegetation map of this same year. In the second example, two sequential vegetation maps are compared. A major problem is often the thematic incongruence of sequential vegetation maps. Afterwards, this can only be resolved by upscaling one or both maps. It is concluded that the use of old data for monitoring purposes can be very valuable, but that this often calls for creative data handling, in which GIS and modern computer programmes are very helpful.

  2. NUMERICAL METHOD OF MIXED FINITE VOLUME-MODIFIED UPWIND FRACTIONAL STEP DIFFERENCE FOR THREE-DIMENSIONAL SEMICONDUCTOR DEVICE TRANSIENT BEHAVIOR PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Yirang YUAN; Qing YANG; Changfeng LI; Tongjun SUN

    2017-01-01

    Transient behavior of three-dimensional semiconductor device with heat conduction is described by a coupled mathematical system of four quasi-linear partial differential equations with initial-boundary value conditions.The electric potential is defined by an elliptic equation and it appears in the following three equations via the electric field intensity.The electron concentration and the hole concentration are determined by convection-dominated diffusion equations and the temperature is interpreted by a heat conduction equation.A mixed finite volume element approximation,keeping physical conservation law,is used to get numerical values of the electric potential and the accuracy is improved one order.Two concentrations and the heat conduction are computed by a fractional step method combined with second-order upwind differences.This method can overcome numerical oscillation,dispersion and decreases computational complexity.Then a three-dimensional problem is solved by computing three successive one-dimensional problems where the method of speedup is used and the computational work is greatly shortened.An optimal second-order error estimate in L2 norm is derived by using prior estimate theory and other special techniques of partial differential equations.This type of mass-conservative parallel method is important and is most valuable in numerical analysis and application of semiconductor device.

  3. Magnitude of the smoking problem, knowledge, attitude and practice, among family members of primary school students

    Directory of Open Access Journals (Sweden)

    Babak Nakhostin-Roohi

    2013-06-01

    Full Text Available Background: smoking is a very important public health problem, urgently requiring immediate and effective measures due to its harmful effect on health. The purpose of this study was to collect baseline information about the magnitude of smoking problem, knowledge, attitude, and practice among family members of primary school students in the northwest region of Iran.Methods: of 55 680 primary school students (the 3th, 4th and 5th grades, 7.1% (n=3 954 were selected using randomized multi-stage cluster sampling. Data collection was conducted in April, May, and June 2011, by means of a self-administered two-page questionnaire.Results: a total of 3 954 students (57.6% boys and 42.3% girls with the mean age of 10.46±1.09 years were evaluated. According to our data, the prevalence of cigarette smoking among fathers was more than other family members (27.1% versus 17.8% whereas the prevalence of water pipe smoking among fathers and other family members was almost similar (9.2% and 9.7% respectively. None of the smoking type was prevalent among mothers (cigarette: 1% and water pipe: 1.1%. Considerable numbers of all students under study had been exposed to secondhand smoke at home (cigarette: 19.8% and water pipe: 7.7%.Conclusions: considering our findings, two procedures recommended to prevail the problem are to provide greater education about hazards of tobacco consumption among students and their family; and to legislate new laws by officials to ban tobacco use at home.

  4. A Survey on Transport Management Practices Associated with Injuries and Health Problems in Horses.

    Science.gov (United States)

    Padalino, Barbara; Raidal, Sharanne L; Hall, Evelyn; Knight, Peter; Celi, Pietro; Jeffcott, Leo; Muscatello, Gary

    2016-01-01

    An online survey was conducted to determine associations between transport management and transport-related injuries and diseases in horses in Australia. The survey was composed of three sections: respondents' demographic information, transport management strategies or procedures (before, during and after transportation) and transport diseases experienced in the previous two year period. Univariate and multivariate modelling was performed exploring associations between variables (respondents' details and transport management strategies) and the following transport-related diseases as outcomes: traumatic injuries, diarrhoea, heat stroke, muscular problems, laminitis, transport pneumonia and colic. The survey generated 797 responses. Traumatic injuries were the most common transport-related problem, with a reported incidence of 45.0%. Younger respondents (30 in a week) were more likely to report transport-related injuries. Injury risk was also linked to the use of protections and tranquilizers prior to transport, and checking horses after the journey. Diarrhoea (20.0%) and heat stroke (10.5%) were reported more by amateur than professional horse carers. Increased risk of heat stroke was linked to the restriction of hay and water prior to transportation. Muscular problems (13.0%) appeared to be exacerbated when horse health was not assessed before journey; whilst the risk of laminitis (2.9%) was around three fold greater when post transport recovery strategies were not applied. Associations were made between transport pneumonia (9.2%) and duration of journey, and with activity (horses involved in racing at greater risk). No associations were seen between the incidence of colic (10.3%) and the variables examined. Study findings should be interpreted with caution as they represent participant perceptions and recall. Nevertheless, results support many current recommendations for safe transportation of horses. They also highlight the need to further investigate many of

  5. Cooperative Problem-Based Learning (CPBL: A Practical PBL Model for a Typical Course

    Directory of Open Access Journals (Sweden)

    Khairiyah Mohd-Yusof

    2011-09-01

    Full Text Available Problem-Based Learning (PBL is an inductive learning approach that uses a realistic problem as the starting point of learning. Unlike in medical education, which is more easily adaptable to PBL, implementing PBL in engineering courses in the traditional semester system set-up is challenging. While PBL is normally implemented in small groups of up to ten students with a dedicated tutor during PBL sessions in medical education, this is not plausible in engineering education because of the high enrolment and large class sizes. In a typical course, implementation of PBL consisting of students in small groups in medium to large classes is more practical. However, this type of implementation is more difficult to monitor, and thus requires good support and guidance in ensuring commitment and accountability of each student towards learning in his/her group. To provide the required support, Cooperative Learning (CL is identified to have the much needed elements to develop the small student groups to functional learning teams. Combining both CL and PBL results in a Cooperative Problem-Based Learning (CPBL model that provides a step by step guide for students to go through the PBL cycle in their teams, according to CL principles. Suitable for implementation in medium to large classes (approximately 40-60 students for one floating facilitator, with small groups consisting of 3-5 students, the CPBL model is designed to develop the students in the whole class into a learning community. This paper provides a detailed description of the CPBL model. A sample implementation in a third year Chemical Engineering course, Process Control and Dynamics, is also described.

  6. [Good agricultural practice (GAP) of Chinese materia medica (CMM) for ten years: achievements, problems and proposals].

    Science.gov (United States)

    Guo, Lan-Ping; Zhang, Yan; Zhu, Shou-Dong; Wang, Gui-Hua; Wang, Xiu; Zhang, Xiao-Bo; Chen, Mei-Lan; He, Ya-Li; Han, Bang-Xing; Chen, Nai-Fu; Huang, Lu-Qi

    2014-04-01

    This paper aims to summarize the achievements during the implementation process of good agricultural practice (GAP) in Chinese Materia Medica (CMM), and on basis of analyzing the existing problems of GAP, to propose further implementation of GAP in TCM growing. Since the launch of GAP in CMM growing ten years ago, it has acquired great achievements, including: (1) The promulgation of a series of measures for the administration of the GAP approval in the CMM growing; (2) The expanded planting area of CMM; (3) The increased awareness of standardized CMM growing among farmers and enterprises; (4) The establishment of GAP implementation bases for CMM growing; (5) The improvement of theory and methodology for CMM growing; (6) The development of a large group of experts and scholars in GAP approval for CMM production. The problems existing in the production include: (1) A deep understanding of GAP and its certification is still needed; (2) The distribution of the certification base is not reasonable; (3) The geo-economics effect and the backward farming practices are thought to be the bottlenecks in the standardization of CMM growing and the scale production of CMM; (4) Low comparative effectiveness limits the development of the GAP; (5) The base of breeding improved variety is blank; (6) The immature of the cultivation technique lead to the risk of production process; (7) The degradation of soil microbial and the continuous cropping obstacle restrict the sustainable development of the GAP base. To further promote the health and orderly GAP in the CMM growing, the authors propose: (1) To change the mode of production; (2) To establish a sound standard system so as to ensure quality products for fair prices; (3) To fully consider the geo-economic culture and vigorously promote the definite cultivating of traditional Chinese medicinal materials; (4) To strengthen the transformation and generalization of basic researches and achievements, in order to provide technical

  7. A geometrical multi-scale numerical method for coupled hygro-thermo-mechanical problems in photovoltaic laminates.

    Science.gov (United States)

    Lenarda, P; Paggi, M

    A comprehensive computational framework based on the finite element method for the simulation of coupled hygro-thermo-mechanical problems in photovoltaic laminates is herein proposed. While the thermo-mechanical problem takes place in the three-dimensional space of the laminate, moisture diffusion occurs in a two-dimensional domain represented by the polymeric layers and by the vertical channel cracks in the solar cells. Therefore, a geometrical multi-scale solution strategy is pursued by solving the partial differential equations governing heat transfer and thermo-elasticity in the three-dimensional space, and the partial differential equation for moisture diffusion in the two dimensional domains. By exploiting a staggered scheme, the thermo-mechanical problem is solved first via a fully implicit solution scheme in space and time, with a specific treatment of the polymeric layers as zero-thickness interfaces whose constitutive response is governed by a novel thermo-visco-elastic cohesive zone model based on fractional calculus. Temperature and relative displacements along the domains where moisture diffusion takes place are then projected to the finite element model of diffusion, coupled with the thermo-mechanical problem by the temperature and crack opening dependent diffusion coefficient. The application of the proposed method to photovoltaic modules pinpoints two important physical aspects: (i) moisture diffusion in humidity freeze tests with a temperature dependent diffusivity is a much slower process than in the case of a constant diffusion coefficient; (ii) channel cracks through Silicon solar cells significantly enhance moisture diffusion and electric degradation, as confirmed by experimental tests.

  8. Numerical solutions of multi-dimensional solidification/melting problems by the dual reciprocity boundary element method

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Shin, Won Ky [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents an effective and simple procedure for the simulation of the motion of the solid-liquid interfacial boundary and the transient temperature field during phase change process. To accomplish this purpose, an iterative implicit solution algorithm has been developed by employing the dual reciprocity boundary element method. The dual reciprocity boundary element approach provided in this paper is much simpler than the usual boundary element method applying a reciprocity principle and an available technique for dealing with domain integral of boundary element formulation simultaneously. The effectiveness of the present analysis method have been illustrated through comparisons of the calculation results of an example with its semi-analytical or other numerical solutions where available. 22 refs., 3 figs. (Author)

  9. 1D and 2D Numerical Modeling for Solving Dam-Break Flow Problems Using Finite Volume Method

    Directory of Open Access Journals (Sweden)

    Szu-Hsien Peng

    2012-01-01

    Full Text Available The purpose of this study is to model the flow movement in an idealized dam-break configuration. One-dimensional and two-dimensional motion of a shallow flow over a rigid inclined bed is considered. The resulting shallow water equations are solved by finite volumes using the Roe and HLL schemes. At first, the one-dimensional model is considered in the development process. With conservative finite volume method, splitting is applied to manage the combination of hyperbolic term and source term of the shallow water equation and then to promote 1D to 2D. The simulations are validated by the comparison with flume experiments. Unsteady dam-break flow movement is found to be reasonably well captured by the model. The proposed concept could be further developed to the numerical calculation of non-Newtonian fluid or multilayers fluid flow.

  10. Numerical solutions of multi-dimensional solidification/melting problems by the dual reciprocity boundary element method

    International Nuclear Information System (INIS)

    Jo, Jong Chull; Shin, Won Ky

    1997-01-01

    This paper presents an effective and simple procedure for the simulation of the motion of the solid-liquid interfacial boundary and the transient temperature field during phase change process. To accomplish this purpose, an iterative implicit solution algorithm has been developed by employing the dual reciprocity boundary element method. The dual reciprocity boundary element approach provided in this paper is much simpler than the usual boundary element method applying a reciprocity principle and an available technique for dealing with domain integral of boundary element formulation simultaneously. The effectiveness of the present analysis method have been illustrated through comparisons of the calculation results of an example with its semi-analytical or other numerical solutions where available

  11. Numerical solutions of multi-dimensional solidification/melting problems by the dual reciprocity boundary element method

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Shin, Won Ky [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    This paper presents an effective and simple procedure for the simulation of the motion of the solid-liquid interfacial boundary and the transient temperature field during phase change process. To accomplish this purpose, an iterative implicit solution algorithm has been developed by employing the dual reciprocity boundary element method. The dual reciprocity boundary element approach provided in this paper is much simpler than the usual boundary element method applying a reciprocity principle and an available technique for dealing with domain integral of boundary element formulation simultaneously. The effectiveness of the present analysis method have been illustrated through comparisons of the calculation results of an example with its semi-analytical or other numerical solutions where available. 22 refs., 3 figs. (Author)

  12. Numerical analysis of electromagnetic fields

    CERN Document Server

    Zhou Pei Bai

    1993-01-01

    Numerical methods for solving boundary value problems have developed rapidly. Knowledge of these methods is important both for engineers and scientists. There are many books published that deal with various approximate methods such as the finite element method, the boundary element method and so on. However, there is no textbook that includes all of these methods. This book is intended to fill this gap. The book is designed to be suitable for graduate students in engineering science, for senior undergraduate students as well as for scientists and engineers who are interested in electromagnetic fields. Objective Numerical calculation is the combination of mathematical methods and field theory. A great number of mathematical concepts, principles and techniques are discussed and many computational techniques are considered in dealing with practical problems. The purpose of this book is to provide students with a solid background in numerical analysis of the field problems. The book emphasizes the basic theories ...

  13. Treatment outcomes of a Numeric Rating Scale (NRS)-guided pharmacological pain management strategy in symptomatic knee and hip osteoarthritis in daily clinical practice.

    NARCIS (Netherlands)

    Snijders, G.F.; Ende, C.H.M. van den; Bemt, B.J.F van den; Riel, P.L.C.M. van; Hoogen, F.H.J. van den; Broeder, A. den

    2012-01-01

    OBJECTIVES: To describe the results of a Numeric Rating Scale (NRS)-guided pharmacological pain management strategy in symptomatic knee and hip osteoarthritis (OA) in daily clinical practice. METHODS: In this observational cohort study, standardised conservative treatment was offered to patients

  14. Fictitious domain methods for elliptic problems with general boundary conditions with an application to the numerical simulation of two phase flows

    International Nuclear Information System (INIS)

    Ramiere, I.

    2006-09-01

    This work is dedicated to the introduction of two original fictitious domain methods for the resolution of elliptic problems (mainly convection-diffusion problems) with general and eventually mixed boundary conditions: Dirichlet, Robin or Neumann. The originality lies in the approximation of the immersed boundary by an approximate interface derived from the fictitious domain Cartesian mesh, which is generally not boundary-fitted to the physical domain. The same generic numerical scheme is used to impose the embedded boundary conditions. Hence, these methods require neither a surface mesh of the immersed boundary nor the local modification of the numerical scheme. We study two modelling of the immersed boundary. In the first one, called spread interface, the approximate immersed boundary is the union of the cells crossed by the physical immersed boundary. In the second one, called thin interface, the approximate immersed boundary lies on sides of mesh cells. Additional algebraic transmission conditions linking both flux and solution jumps through the thin approximate interface are introduced. The fictitious problem to solve as well as the treatment of the embedded boundary conditions are detailed for the two methods. A Q1 finite element scheme is implemented for the numerical validation of the spread interface approach while a new cell-centered finite volume scheme is derived for the thin interface approach with immersed jumps. Each method is then combined to multilevel local mesh refinement algorithms (with solution or flux residual) to increase the precision of the solution in the vicinity of the immersed interface. A convergence analysis of a Q1 finite element method with non-boundary fitted meshes is also presented. This study proves the convergence rates of the present methods. Among the various industrial applications, the simulation on a model of heat exchanger in french nuclear power plants enables us to appreciate the performances of the fictitious domain

  15. Practice and application of problem-based learning in evidence-based medicine teaching

    Directory of Open Access Journals (Sweden)

    Tian-Ao Li

    2014-10-01

    Full Text Available AIM:To investigate the effect of problem-based learning(PBLused in the teaching of medical students' evidence-based medicine(EBM.METHODS: Five classes(total 147 studentswere randomly selected as experimental(PBLgroup, at the same time, another 5 classes(total 149 studentswere also randomly selected as control group, using traditional teaching method(lecture-based learning, LBLin 2010 grade. The final examination scores of the experimental group were compared with control at the end of term. In addition, all students were interviewed using self-administered questionnaire to obtain their evaluation for PBL practice. SPSS13.0 software was used for statistical analysis.RESULTS: The homogeneity test in baseline survey showed that the basic characteristics between the two groups of students were no significant differences, and were comparable(P>0.05. Final exam results showed that in addition to the scores of the EBM basic knowledge indicated no significant difference between two groups of students(P>0.05, for the 5 steps of EBM procedure, namely, asking questions, finding the best evidence, evaluating the evidence, using and practicing the evidence, re-evaluating the evidence, and the total scores between the two groups, there were significant statistically differences(PP>0.05in aspects of better understanding classroom knowledge, improving language expression ability, and writing skill exercises. And other residual items had a significant difference(PPCONCLUSION:PBL teaching mode can effectively improve teaching effectiveness and the quality of EBM teaching, so the this teaching mode is worth further popularizing.

  16. The problems of cross-border personal bankruptcy in russian and chinese legislation and practice

    Directory of Open Access Journals (Sweden)

    Tatiana Kareva

    2017-01-01

    Full Text Available The subject of the article is the legal and practical problems of cross-border personal bankruptcyin Russia and China.The main goal of this work is to analyze the major issues and obstacles in recognition andenforcement of Russian individual bankruptcy decisions in China and introduce it to Russianscholars and legal professionals.The methodological basis is analysis of the Russian and Chinese legislation, judicial practiceand special literatureThe results, scope of application. This article discusses the possibility of applying the provisionsof the Federal Law On Insolvency (Bankruptcy to the Chinese nationals registered asindividual entrepreneurs in Russia. The article also reviews the Chinese legal regulation andoffers recommendations on execution of the court judgments on bankruptcy and collectionof debts from the PRC nationals. Existing Russian legislation allows to recognize the foreignnationals as bankrupts. The provisions on the cross-border insolvency also apply to them.The bankruptcy in China is not applied currently to the individuals, although theoretically itmay affect their property sphere during the bankruptcy of an individual private enterprise.Conclusions. The cross-border insolvency of the Chinese nationals encounters obstacles on threelevels. Firstly, the awards of the Russian arbitration courts have not been practically enforced inPRC due to inadequate notification of the Chinese party in the case. Secondly, Chinese courts inprinciple are extremely reluctant in recognizing foreign judgments on bankruptcy, such cases areexceptional. Thirdly, there is no personal bankruptcy institution in the PRC, while similar procedureslike bankruptcy of individual private enterprises are not applied in reality, and there are nolegislative prospects for the personal bankruptcy in the nearest future. Therefore, when conductingthe bankruptcy procedure for the Chinese nationals on the Russian territory, one can onlycount on their property located

  17. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    KAUST Repository

    Bao, Kai

    2012-10-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  18. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    KAUST Repository

    Bao, Kai; Shi, Yi; Sun, Shuyu; Wang, Xiaoping

    2012-01-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  19. Optimization and public radiation exposure. Some problems in principle and practice

    International Nuclear Information System (INIS)

    Mitchell, N.T.

    1979-01-01

    In its 1977 recommendations the International Commission on Radiological Protection has laid particular emphasis on application of the principle of optimization in setting controls on the disposal of radioactive wastes that will result in radiation exposure to the public. This principle has been followed in the UK for a long time though it is only recently that it has been possible to apply an even semiquantitative technique in its application. The paper examines the principles of differential cost-benefit analysis and discusses problems in applying this technique. Consideration is given to the assessment of parameter values to be used in the differential cost-benefit equation, these being protection costs, collective dose commitment (and, from it, health detriment) and the more difficult process of attaching a cost to social detriment. Finally, the application of the technique in practice is discussed by illustration of experience gained in the control of liquid effluents from nuclear power stations and a fuel reprocessing plant. It is found that despite the complexity of the technique and the technical difficulties in estimation of many of the parameter values, especially detriment, differential cost-benefit analysis fills a useful if limited role. However, a great many value judgements, some of them implicit in developing data to put into the overall equation, are still required. (author)

  20. Development of a numerical experiment technique to solve inverse gamma-ray transport problems with application to nondestructive assay of nuclear waste barrels

    International Nuclear Information System (INIS)

    Chang, C.J.; Anghaie, S.

    1998-01-01

    A numerical experimental technique is presented to find an optimum solution to an undetermined inverse gamma-ray transport problem involving the nondestructive assay of radionuclide inventory in a nuclear waste drum. The method introduced is an optimization scheme based on performing a large number of numerical simulations that account for the counting statistics, the nonuniformity of source distribution, and the heterogeneous density of the self-absorbing medium inside the waste drum. The simulation model uses forward projection and backward reconstruction algorithms. The forward projection algorithm uses randomly selected source distribution and a first-flight kernel method to calculate external detector responses. The backward reconstruction algorithm uses the conjugate gradient with nonnegative constraint or the maximum likelihood expectation maximum method to reconstruct the source distribution based on calculated detector responses. Total source activity is determined by summing the reconstructed activity of each computational grid. By conducting 10,000 numerical simulations, the error bound and the associated confidence level for the prediction of total source activity are determined. The accuracy and reliability of the simulation model are verified by performing a series of experiments in a 208-ell waste barrel. Density heterogeneity is simulated by using different materials distributed in 37 egg-crate-type compartments simulating a vertical segment of the barrel. Four orthogonal detector positions are used to measure the emerging radiation field from the distributed source. Results of the performed experiments are in full agreement with the estimated error and the confidence level, which are predicted by the simulation model

  1. Modelling the transition between fixed and mobile bed conditions in two-phase free-surface flows: The Composite Riemann Problem and its numerical solution

    Science.gov (United States)

    Rosatti, Giorgio; Zugliani, Daniel

    2015-03-01

    In a two-phase free-surface flow, the transition from a mobile-bed condition to a fixed-bed one (and vice versa) occurs at a sharp interface across which the relevant system of partial differential equations changes abruptly. This leads to the possibility of conceiving a new type of Riemann Problem (RP), which we have called Composite Riemann Problem (CRP), where not only the initial constant values of the variables but also the system of equations change from left to right of a discontinuity. In this paper, we present a strategy for solving a CRP by reducing it to a standard RP of a single, composite system of equations. This can be obtained by combining the two original systems by means of a suitable weighting function, namely the erodibility variable, and the introduction of an appropriate differential equation for this quantity. In this way, the CRP problem can be analyzed theoretically with standard methods, and the features of the solutions can be clearly identified. In particular, a stationary contact wave is able to correctly describe the sharp transition between mobile- and fixed-bed conditions. A finite volume scheme based on the Multiple Averages Generalized Roe approach (Rosatti and Begnudelli (2013) [22]) was used to numerically solve the fixed-mobile CRP. Several test cases demonstrate the effectiveness, exact well balanceness and high accuracy of the scheme when applied to problems that fall within the physical range of applicability of the relevant mathematical model.

  2. Generalist solutions to complex problems: generating practice-based evidence--the example of managing multi-morbidity.

    Science.gov (United States)

    Reeve, Joanne; Blakeman, Tom; Freeman, George K; Green, Larry A; James, Paul A; Lucassen, Peter; Martin, Carmel M; Sturmberg, Joachim P; van Weel, Chris

    2013-08-07

    A growing proportion of people are living with long term conditions. The majority have more than one. Dealing with multi-morbidity is a complex problem for health systems: for those designing and implementing healthcare as well as for those providing the evidence informing practice. Yet the concept of multi-morbidity (the presence of >2 diseases) is a product of the design of health care systems which define health care need on the basis of disease status. So does the solution lie in an alternative model of healthcare? Strengthening generalist practice has been proposed as part of the solution to tackling multi-morbidity. Generalism is a professional philosophy of practice, deeply known to many practitioners, and described as expertise in whole person medicine. But generalism lacks the evidence base needed by policy makers and planners to support service redesign. The challenge is to fill this practice-research gap in order to critically explore if and when generalist care offers a robust alternative to management of this complex problem. We need practice-based evidence to fill this gap. By recognising generalist practice as a 'complex intervention' (intervening in a complex system), we outline an approach to evaluate impact using action-research principles. We highlight the implications for those who both commission and undertake research in order to tackle this problem. Answers to the complex problem of multi-morbidity won't come from doing more of the same. We need to change systems of care, and so the systems for generating evidence to support that care. This paper contributes to that work through outlining a process for generating practice-based evidence of generalist solutions to the complex problem of person-centred care for people with multi-morbidity.

  3. The numerical study and comparison of radial basis functions in applications of the dual reciprocity boundary element method to convection-diffusion problems

    Science.gov (United States)

    Chanthawara, Krittidej; Kaennakham, Sayan; Toutip, Wattana

    2016-02-01

    The methodology of Dual Reciprocity Boundary Element Method (DRBEM) is applied to the convection-diffusion problems and investigating its performance is our first objective of the work. Seven types of Radial Basis Functions (RBF); Linear, Thin-plate Spline, Cubic, Compactly Supported, Inverse Multiquadric, Quadratic, and that proposed by [12], were closely investigated in order to numerically compare their effectiveness drawbacks etc. and this is taken as our second objective. A sufficient number of simulations were performed covering as many aspects as possible. Varidated against both exacts and other numerical works, the final results imply strongly that the Thin-Plate Spline and Linear type of RBF are superior to others in terms of both solutions' quality and CPU-time spent while the Inverse Multiquadric seems to poorly yield the results. It is also found that DRBEM can perform relatively well at moderate level of convective force and as anticipated becomes unstable when the problem becomes more convective-dominated, as normally found in all classical mesh-dependence methods.

  4. Mathematical and numerical methods for the nonlinear hyperbolic propagation problem: d2GAMMA/dt2 = d/dz [dGAMMA/dt dGAMMA/dz

    International Nuclear Information System (INIS)

    Stanco, L.; Vaccaro, V.G.; Funk, U.; Krueger, U.; Mika, K.; Wuestefeld, G.

    1982-03-01

    In the first part of this report a physical model is presented, which describes the deforming of a bunch in a storage ring influenced only by its own space charge field. A system of two differential equations for the density and the momentum of the particles is set up, which is independent of any special machine parameter. Due to the sign of the inductance of the chamber walls and the sign of the dispersion of the revolution frequency, we distinguish between a de-bunching and a self-bunching situation. The de-bunching corresponds to a nonlinear hyperbolic propagation problem well-known in gas dynamics, and the self-bunching to a nonlinear elliptic initial value problem. The second part deals with a mathematical and numerical treatment of an approximate equation for the hyperbolic case. For this nonlinear second order partial differential equation we first present three particular integrals: the solution by separating the variables, the similarity solution, and the solution for a parabolic initial distribution of the density. For a more realistic initial condition, we must resort to other methods: Results are obtained in three different ways, first from a highly accurate Taylor series expansion, second from a common finite difference method, and thirdly from the numerical method of characteristics. The appearance of a shock discontinuity is furthermore established in each of these cases. (orig.)

  5. Inverse problems using ANN in long range atmospheric dispersion with signature analysis picked scattered numerical sensors from CFD

    International Nuclear Information System (INIS)

    Sharma, Pavan K.; Gera, B.; Ghosh, A.K.; Kushwaha, H.S.

    2010-01-01

    Scalar dispersion in the atmosphere is an important area wherein different approaches are followed in development of good analytical model. The analyses based on Computational Fluid Dynamics (CFD) codes offer an opportunity of model development based on first principles of physics and hence such models have an edge over the existing models. Both forward and backward calculation methods are being developed for atmospheric dispersion around NPPs at BARC Forward modeling methods, which describe the atmospheric transport from sources to receptors, use forward-running transport and dispersion models or computational fluid dynamics models which are run many times, and the resulting dispersion field is compared to observations from multiple sensors. Backward or inverse modeling methods use only one model run in the reverse direction from the receptors to estimate the upwind sources. Inverse modeling methods include adjoint and tangent linear models, Kalman filters, and variational data assimilation, and neural network. The present paper is aimed at developing a new approach where the identified specific signatures at receptor points form the basis for source estimation or inversions. This approach is expected to reduce the large transient data sets to reduced and meaningful data sets. In fact this reduces the inherently transient data set into a time independent mean data set. Forward computation were carried out with CFD code for various case to generate a large set of data to train the ANN. Specific signature analysis was carried out to find the parameters of interest for ANN training like peak concentration, time to reach peak concentration and time to fall, the ANN was trained with data and source strength and location were predicted from ANN. Inverse problem was performed using ANN approach in long range atmospheric dispersion. An illustration of application of CFD code for atmospheric dispersion studies for a hypothetical case is also included in the paper. (author)

  6. Level of satisfaction of older persons with their general practitioner and practice: role of complexity of health problems.

    Directory of Open Access Journals (Sweden)

    Antonius J Poot

    Full Text Available BACKGROUND: Satisfaction is widely used to evaluate and direct delivery of medical care; a complicated relationship exists between patient satisfaction, morbidity and age. This study investigates the relationships between complexity of health problems and level of patient satisfaction of older persons with their general practitioner (GP and practice. METHODS AND FINDINGS: This study is embedded in the ISCOPE (Integrated Systematic Care for Older Persons study. Enlisted patients aged ≥75 years from 59 practices received a written questionnaire to screen for complex health problems (somatic, functional, psychological and social. For 2664 randomly chosen respondents (median age 82 years; 68% female information was collected on level of satisfaction (satisfied, neutral, dissatisfied with their GP and general practice, and demographic and clinical characteristics including complexity of health problems. Of all participants, 4% was dissatisfied with their GP care, 59% neutral and 37% satisfied. Between these three categories no differences were observed in age, gender, country of birth or education level. The percentage of participants dissatisfied with their GP care increased from 0.4% in those with 0 problem domains to 8% in those with 4 domains, i.e. having complex health problems (p<0.001. Per additional health domain with problems, the risk of being dissatisfied increased 1.7 times (95% CI 1.4-2.14; p<0.001. This was independent of age, gender, and demographic and clinical parameters (adjusted OR 1.4, 95% CI 1.1-1.8; p = 0.021. CONCLUSION: In older persons, dissatisfaction with general practice is strongly correlated with rising complexity of health problems, independent of age, demographic and clinical parameters. It remains unclear whether complexity of health problems is a patient characteristic influencing the perception of care, or whether the care is unable to handle the demands of these patients. Prospective studies are needed to

  7. Numerical analysis

    CERN Document Server

    Brezinski, C

    2012-01-01

    Numerical analysis has witnessed many significant developments in the 20th century. This book brings together 16 papers dealing with historical developments, survey papers and papers on recent trends in selected areas of numerical analysis, such as: approximation and interpolation, solution of linear systems and eigenvalue problems, iterative methods, quadrature rules, solution of ordinary-, partial- and integral equations. The papers are reprinted from the 7-volume project of the Journal of Computational and Applied Mathematics on '/homepage/sac/cam/na2000/index.html<

  8. Physical multiscale modeling and numerical simulation of electrochemical devices for energy conversion and storage from theory to engineering to practice

    CERN Document Server

    Franco, Alejandro A; Bessler, Wolfgang G

    2015-01-01

    This book reviews the use of innovative physical multiscale modeling methods to deeply understand the electrochemical mechanisms and numerically simulate the structure and properties of electrochemical devices for energy storage and conversion.

  9. Urban Agriculture Practices and Health Problems among Farmers Operating on a University Campus in Kumasi, Ghana

    Directory of Open Access Journals (Sweden)

    Nana O.B. Ackerson

    2010-06-01

    Full Text Available Urban agriculture, a world-wide practice, faces both environmental and health challenges. Farmers are susceptible to occupational and other water-related health risks. The research identified health problems related to urban agricultural farming through farmers’ social characteristics and agricultural practices. Thorough interviews, using structured questionnaires, were carried out. Sixty three farmers responded to questions ranging from agricultural practices to health problems encountered. The findings showed that farmers apply both organic and inorganic fertilisers while 97% used pesticides of varying active ingredients at different application rates. Only 10% used personal protective clothing during the application of pesticides. Overhead irrigation was carried out using a watering can. Eighty four percent and 13% of the respondents utilised water from shallow wells and shallow wells mixed with contaminated stream, respectively. Besides schistosomiasis and cholera, other bacterial diseases, nematode infections, malaria, headaches, dermatological, visual, cardiac, and respiratory problems were common health complaints. Headache complaints were the most common (75%.L’agriculture urbaine, une pratique qui a cours dans le monde entier, est confrontée à des défis d’ordre environnemental et sanitaire. Les agriculteurs sont exposés à divers risques professionnels, et notamment à ceux que l'eau peut poser pour leur santé. Cette étude a identifié les problèmes de santé liés à l’agriculture urbaine en fonction des caractéristiques sociales et des pratiques des agriculteurs. Des entretiens approfondis ont été conduits en suivant des questionnaires structurés. Soixante-trois fermiers ont répondu aux questions, qui abordaient leurs pratiques agricoles ainsi que leurs problèmes de santé. Les résultats montrent que les fermiers emploient aussi bien des engrais organiques que non organiques, et que 97 % utilisent des pesticides

  10. Instructional Designers' Media Selection Practices for Distributed Problem-Based Learning Environments

    Science.gov (United States)

    Fells, Stephanie

    2012-01-01

    The design of online or distributed problem-based learning (dPBL) is a nascent, complex design problem. Instructional designers are challenged to effectively unite the constructivist principles of problem-based learning (PBL) with appropriate media in order to create quality dPBL environments. While computer-mediated communication (CMC) tools and…

  11. Numerical procedure for determining pressure limits on borehole instability problems; Procedimento numerico para determimacao dos limites de pressao em problemas de instabilidade de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Muller, A.L. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Grupo de Tecnologia em Computacao Grafica (TecGraf); Vargas Junior, E.A. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil; Vaz, L.E. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Engenharia. Dept. de Mecanica Aplicada e Estruturas; Goncalves, C.J. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    In the boreholes projects, the minimization of the instability problems is extreme importance. In the boreholes instability analysis, two failure mechanisms are generally considered, namely, failure due to either tensile or compressive stresses. Considering these mechanisms, the correct determination of the lower and upper limits of pressures, generated by the drilling fluid in the walls of the boreholes, is an alternative for minimization of the instability problems. The mechanisms of compression or tensile failure can be described in terms of mechanical and fluid flow responses of the transient fluid mechanical coupling problem. This paper proposes a numerical procedure, using finite elements, of the coupled fluid mechanical processes, for automatically determining the lower and upper limits of pressures on the walls of borehole, to ensure, according assumptions and criteria of failure pre-established, the stability of the same. The automatic obtaining those values has the purpose of replace the approximate obtaining by trial and error processes. A hypothetical example of application is show, and from this, inferred considerations about the proposed procedure. (author)

  12. Fifth Anniversary youth scientifically-practical conference Nuclear-industrial complex of Ural: problems and prospects. Theses of reports

    International Nuclear Information System (INIS)

    2009-01-01

    Theses of reports of the Fifth Anniversary youth scientifically-practical conference Nuclear-industrial complex of Ural: problems and prospects (21-23 April 2009, Ozersk) are presented. The book contains abstracts of papers of fourth thematic sections: SNF reprocessing: science and industry; Radioecology and radiobiology; Advanced science-intensive technologies and materials; Education and training for NFC plants

  13. The solicitation of an undue advantage: theoretical and practical problems caused by the legislative virus, and their comprehensive solution

    Directory of Open Access Journals (Sweden)

    Василь Миколайович Киричко

    2018-03-01

    The solution to the theoretical and practical problems caused by the specified virus is possible only by introducing several changes to the system of the Criminal Code of Ukraine. Projects of such changes are developed by the author and reflected in the publication. In case of their adoption, the specified legislative virus will be completely eliminated.

  14. Perceiving the Problem of Poverty and Schooling: Deconstructing the Class Stereotypes that Mis-Shape Education Practice and Policy

    Science.gov (United States)

    Gorski, Paul C.

    2012-01-01

    A rich history of scholarship has demonstrated the ways in which popular stereotypes of disenfranchised communities, including people living in poverty, affect individual biases and preconceptions. Less attention has been paid to the ways in which such stereotypes help frame policy and practice responses regarding social problems, such as the…

  15. Generalist solutions to complex problems: generating practice-based evidence - the example of managing multi-morbidity

    NARCIS (Netherlands)

    Reeve, J.; Blakeman, T.; Freeman, G.K.; Green, L.A.; James, P.A.; Lucassen, P.L.; Martin, C.M.; Sturmberg, J.P.; Weel, C. van

    2013-01-01

    BACKGROUND: A growing proportion of people are living with long term conditions. The majority have more than one. Dealing with multi-morbidity is a complex problem for health systems: for those designing and implementing healthcare as well as for those providing the evidence informing practice. Yet

  16. Level of satisfaction of older persons with their general practitioner and practice: role of complexity of health problems.

    Science.gov (United States)

    Poot, Antonius J; den Elzen, Wendy P J; Blom, Jeanet W; Gussekloo, Jacobijn

    2014-01-01

    Satisfaction is widely used to evaluate and direct delivery of medical care; a complicated relationship exists between patient satisfaction, morbidity and age. This study investigates the relationships between complexity of health problems and level of patient satisfaction of older persons with their general practitioner (GP) and practice. This study is embedded in the ISCOPE (Integrated Systematic Care for Older Persons) study. Enlisted patients aged ≥75 years from 59 practices received a written questionnaire to screen for complex health problems (somatic, functional, psychological and social). For 2664 randomly chosen respondents (median age 82 years; 68% female) information was collected on level of satisfaction (satisfied, neutral, dissatisfied) with their GP and general practice, and demographic and clinical characteristics including complexity of health problems. Of all participants, 4% was dissatisfied with their GP care, 59% neutral and 37% satisfied. Between these three categories no differences were observed in age, gender, country of birth or education level. The percentage of participants dissatisfied with their GP care increased from 0.4% in those with 0 problem domains to 8% in those with 4 domains, i.e. having complex health problems (ppatient characteristic influencing the perception of care, or whether the care is unable to handle the demands of these patients. Prospective studies are needed to investigate the causal associations between care organization, patient characteristics, indicators of quality, and patient perceptions.

  17. Semidefinite linear complementarity problems

    International Nuclear Information System (INIS)

    Eckhardt, U.

    1978-04-01

    Semidefinite linear complementarity problems arise by discretization of variational inequalities describing e.g. elastic contact problems, free boundary value problems etc. In the present paper linear complementarity problems are introduced and the theory as well as the numerical treatment of them are described. In the special case of semidefinite linear complementarity problems a numerical method is presented which combines the advantages of elimination and iteration methods without suffering from their drawbacks. This new method has very attractive properties since it has a high degree of invariance with respect to the representation of the set of all feasible solutions of a linear complementarity problem by linear inequalities. By means of some practical applications the properties of the new method are demonstrated. (orig.) [de

  18. A novel numerical approach for the solution of the problem of two-phase, immiscible flow in porous media: Application to LNAPL and DNAPL

    KAUST Repository

    Salama, Amgad

    2012-06-17

    The flow of two immiscible fluids in porous media is ubiquitous particularly in petroleum exploration and extraction. The displacement of one fluid by another immiscible with it represents a very important aspect in what is called enhanced oil recovery. Another example is related to the long-term sequestration of carbon dioxide, CO2 , in deep geologic formations. In this technique, supercritical CO2 is introduced into deep saline aquifer where it displaces the hosting fluid. Furthermore, very important classes of contaminants that are very slightly soluble in water and represent a huge concern if they get introduced to groundwater could basically be assumed immiscible. These are called light non-aqueous phase liquids (LNAPL) and dense non-aqueous phase liquids (DNAPL). All these applications necessitate that efficient algorithms be developed for the numerical solution of these problems. In this work we introduce the use of shifting matrices to numerically solving the problem of two-phase immiscible flows in the subsurface. We implement the cell-center finite difference method which discretizes the governing set of partial differential equations in conservative manner. Unlike traditional solution methodologies, which are based on performing the discretization on a generic cell and solve for all the cells within a loop, in this technique, the cell center information for all the cells are obtained all at once without loops using matrix oriented operations. This technique is significantly faster than the traditional looping algorithms, particularly for larger systems when coding using languages that require repeating interpretation each time a loop is called like Mat Lab, Python and the like. We apply this technique to the transport of LNAPL and DNAPL into a rectangular domain.

  19. Educational Effects and Problems on Cooperative Education for Training Practical Engineer at Anan National College of Technology

    Science.gov (United States)

    Harano, Tomoki; Yoshimura, Hiroshi; Yasuno, Emiko; Uehara, Nobutomo

    The first author has devised the new cooperative education program to adopt the curricula at Colleges of Technology in Japan. The program consists of the practical work programs at manufacturing industries for three weeks and two weeks in every summer and spring vacation at third to fourth grade year, to enhance the communication skill, and to acquire the practical manufacturing technology and so on. In addition, the program has the practical design project of the manufacturing industry to cultivate the problem-solving skill for the fifth grade students at last. The program has many participants that are forty industry companies and seventy students in successfully. It is found that the program is to enhance the communication skill, writing skill and self-confident as a practical engineer by the iterative work.

  20. Problems in fluid flow

    International Nuclear Information System (INIS)

    Brasch, D.J.

    1986-01-01

    Chemical and mineral engineering students require texts which give guidance to problem solving to complement their main theoretical texts. This book has a broad coverage of the fluid flow problems which these students may encounter. The fundamental concepts and the application of the behaviour of liquids and gases in unit operation are dealt with. The book is intended to give numerical practice; development of theory is undertaken only when elaboration of treatments available in theoretical texts is absolutely necessary