Integrated Numerical Experiments (INEX) and the Free-Electron Laser Physical Process Code (FELPPC)
International Nuclear Information System (INIS)
Thode, L.E.; Chan, K.C.D.; Schmitt, M.J.; McKee, J.; Ostic, J.; Elliott, C.J.; McVey, B.D.
1990-01-01
The strong coupling of subsystem elements, such as the accelerator, wiggler, and optics, greatly complicates the understanding and design of a free electron laser (FEL), even at the conceptual level. To address the strong coupling character of the FEL the concept of an Integrated Numerical Experiment (INEX) was proposed. Unique features of the INEX approach are consistency and numerical equivalence of experimental diagnostics. The equivalent numerical diagnostics mitigates the major problem of misinterpretation that often occurs when theoretical and experimental data are compared. The INEX approach has been applied to a large number of accelerator and FEL experiments. Overall, the agreement between INEX and the experiments is very good. Despite the success of INEX, the approach is difficult to apply to trade-off and initial design studies because of the significant manpower and computational requirements. On the other hand, INEX provides a base from which realistic accelerator, wiggler, and optics models can be developed. The Free Electron Laser Physical Process Code (FELPPC) includes models developed from INEX, provides coupling between the subsystem models, and incorporates application models relevant to a specific trade-off or design study. In other words, FELPPC solves the complete physical process model using realistic physics and technology constraints. Because FELPPC provides a detailed design, a good estimate for the FEL mass, cost, and size can be made from a piece-part count of the FEL. FELPPC requires significant accelerator and FEL expertise to operate. The code can calculate complex FEL configurations including multiple accelerator and wiggler combinations
Sotiropoulos, F.; Kang, S.; Chamorro, L. P.; Hill, C.
2011-12-01
The field of MHK energy is still in its infancy lagging approximately a decade or more behind the technology and development progress made in wind energy engineering. Marine environments are characterized by complex topography and three-dimensional (3D) turbulent flows, which can greatly affect the performance and structural integrity of MHK devices and impact the Levelized Cost of Energy (LCoE). Since the deployment of multi-turbine arrays is envisioned for field applications, turbine-to-turbine interactions and turbine-bathymetry interactions need to be understood and properly modeled so that MHK arrays can be optimized on a site specific basis. Furthermore, turbulence induced by MHK turbines alters and interacts with the nearby ecosystem and could potentially impact aquatic habitats. Increased turbulence in the wake of MHK devices can also change the shear stress imposed on the bed ultimately affecting the sediment transport and suspension processes in the wake of these structures. Such effects, however, remain today largely unexplored. In this work a science-based approach integrating state-of-the-art experimentation with high-resolution computational fluid dynamics is proposed as a powerful strategy for optimizing the performance of MHK devices and assessing environmental impacts. A novel numerical framework is developed for carrying out Large-Eddy Simulation (LES) in arbitrarily complex domains with embedded MHK devices. The model is able to resolve the geometrical complexity of real-life MHK devices using the Curvilinear Immersed Boundary (CURVIB) method along with a wall model for handling the flow near solid surfaces. Calculations are carried out for an axial flow hydrokinetic turbine mounted on the bed of rectangular open channel on a grid with nearly 200 million grid nodes. The approach flow corresponds to fully developed turbulent open channel flow and is obtained from a separate LES calculation. The specific case corresponds to that studied
Sotiropoulos, Fotis; Angelidis, Dionysios; Mendelson, Leah; Techet, Alexandra
2017-11-01
Evolution has enabled fish to develop a range of thrust producing mechanisms to allow skillful movement and give them the ability to catch prey or avoid danger. Several experimental and numerical studies have been performed to investigate how complex maneuvers are executed and develop bioinspired strategies for aquatic robot design. We will discuss recent numerical advances toward the development of a computational framework for performing turbulent, two-phase flow, fluid-structure-interaction (FSI) simulations to investigate the dynamics of aquatic jumpers. We will also discuss the integration of such numerics with high-speed imaging and particle image velocimetry data to reconstruct anatomic fish models and prescribe realistic kinematics of fish motion. The capabilities of our method will be illustrated by applying it to simulate the motion of a small scale archer fish jumping out of the water to capture prey. We will discuss the rich vortex dynamics emerging during the hovering, rapid upward and gliding phases. The simulations will elucidate the thrust production mechanisms by the movement of the pectoral and anal fins and we will show that the fins significantly contribute to the rapid acceleration.
Montagna, Chiara; Perugini, Diego; De Campos, Christina; Longo, Antonella; Dingwell, Donald Bruce; Papale, Paolo
2015-04-01
Arrival of magma from depth into shallow reservoirs and associated mixing processes have been documented as possible triggers of explosive eruptions. Quantifying the timing from beginning of mixing to eruption is of fundamental importance in volcanology in order to put constraints about the possible onset of a new eruption. Here we integrate numerical simulations and high-temperature experiment performed with natural melts with the aim to attempt identifying the mixing-to-eruption timescales. We performed two-dimensional numerical simulations of the arrival of gas-rich magmas into shallow reservoirs. We solve the fluid dynamics for the two interacting magmas evaluating the space-time evolution of the physical properties of the mixture. Convection and mingling develop quickly into the chamber and feeding conduit/dyke. Over time scales of hours, the magmas in the reservoir appear to have mingled throughout, and convective patterns become harder to identify. High-temperature magma mixing experiments have been performed using a centrifuge and using basaltic and phonolitic melts from Campi Flegrei (Italy) as initial end-members. Concentration Variance Decay (CVD), an inevitable consequence of magma mixing, is exponential with time. The rate of CVD is a powerful new geochronometer for the time from mixing to eruption/quenching. The mingling-to-eruption time of three explosive volcanic eruptions from Campi Flegrei (Italy) yield durations on the order of tens of minutes. These results are in perfect agreement with the numerical simulations that suggest a maximum mixing time of a few hours to obtain a hybrid mixture. We show that integration of numerical simulation and high-temperature experiments can provide unprecedented results about mixing processes in volcanic systems. The combined application of numerical simulations and CVD geochronometer to the eruptive products of active volcanoes could be decisive for the preparation of hazard mitigation during volcanic unrest.
Cuba: Multidimensional numerical integration library
Hahn, Thomas
2016-08-01
The Cuba library offers four independent routines for multidimensional numerical integration: Vegas, Suave, Divonne, and Cuhre. The four algorithms work by very different methods, and can integrate vector integrands and have very similar Fortran, C/C++, and Mathematica interfaces. Their invocation is very similar, making it easy to cross-check by substituting one method by another. For further safeguarding, the output is supplemented by a chi-square probability which quantifies the reliability of the error estimate.
Methods for enhancing numerical integration
International Nuclear Information System (INIS)
Doncker, Elise de
2003-01-01
We give a survey of common strategies for numerical integration (adaptive, Monte-Carlo, Quasi-Monte Carlo), and attempt to delineate their realm of applicability. The inherent accuracy and error bounds for basic integration methods are given via such measures as the degree of precision of cubature rules, the index of a family of lattice rules, and the discrepancy of uniformly distributed point sets. Strategies incorporating these basic methods often use paradigms to reduce the error by, e.g., increasing the number of points in the domain or decreasing the mesh size, locally or uniformly. For these processes the order of convergence of the strategy is determined by the asymptotic behavior of the error, and may be too slow in practice for the type of problem at hand. For certain problem classes we may be able to improve the effectiveness of the method or strategy by such techniques as transformations, absorbing a difficult part of the integrand into a weight function, suitable partitioning of the domain, transformations and extrapolation or convergence acceleration. Situations warranting the use of these techniques (possibly in an 'automated' way) are described and illustrated by sample applications
An integrated numerical protection system (SPIN)
International Nuclear Information System (INIS)
Savornin, J.L.; Bouchet, J.M.; Furet, J.L.; Jover, P.; Sala, A.
1978-01-01
Developments in technology have now made it possible to perform more sophisticated protection functions which follow more closely the physical phenomena to be monitored. For this reason the Commissariat a l'energie atomique, Merlin-Gerin, Cerci and Framatome have embarked on the joint development of an Integrated Numerical Protection System (SPIN) which will fulfil this objective and will improve the safety and availability of power stations. The system described involves the use of programmed numerical techniques and a structure based on multiprocessors. The architecture has a redundancy of four. Throughout the development of the project the validity of the studies was confirmed by experiments. A first numerical model of a protection function was tested in the laboratory and is now in operation in a power station. A set of models was then introduced for checking the main components of the equipment finally chosen prior to building and testing a prototype. (author)
Numerical approach to one-loop integrals
International Nuclear Information System (INIS)
Fujimoto, Junpei; Shimizu, Yoshimitsu; Kato, Kiyoshi; Oyanagi, Yoshio.
1992-01-01
Two numerical methods are proposed for the calculation of one-loop scalar integrals. In the first method, the singularity is cancelled by the symmetrization of the integrand and the integration is done by a Monte-Carlo method. In the second one, after the transform of the integrand into a standard form, the integral is reduced into a regular numerical integral. These methods provide us practical tools to evaluate one-loop Feynman diagrams with desired numerical accuracy. They are extended to the integral with numerator and the treatment of the one-loop virtual correction to the cross section is also presented. (author)
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.
Numerical studies on divertor experiments
International Nuclear Information System (INIS)
Ueda, N.; Itoh, K.; Itoh, S.-I.; Tanaka, M.; Hasegawa, M.; Shoji, T.; Sugihara, M.
1988-04-01
Numerical analysis on the divertor experiments such as JFT-2M tokamak is made by use of the two-dimensional time-dependent simulation code. The plasma in the scrape-off layer (SOL) and divertor region is solved for the given particle and heat sources from the main plasma, Γ p and Q T . Effect of the direction of the toroidal magnetic field is studied. It is found that the heat flux which is proportional to b vector x ∇T i has influences on the divertor plasmas, but has a small effect on the parameters on the midplane in the framework of the fluid model. Parameter survey on Γ p and Q T is made. The transient response of the SOL/divertor plasma to the sudden change of Γ p and Q T is studied. Time delay in the SOL and divertor region is calculated. (author)
An Integrative Theory of Numerical Development
Siegler, Robert; Lortie-Forgues, Hugues
2014-01-01
Understanding of numerical development is growing rapidly, but the volume and diversity of findings can make it difficult to perceive any coherence in the process. The integrative theory of numerical development posits that a coherent theme is present, however--progressive broadening of the set of numbers whose magnitudes can be accurately…
Drusch, M.
2007-02-01
Satellite-derived surface soil moisture data sets are readily available and have been used successfully in hydrological applications. In many operational numerical weather prediction systems the initial soil moisture conditions are analyzed from the modeled background and 2 m temperature and relative humidity. This approach has proven its efficiency to improve surface latent and sensible heat fluxes and consequently the forecast on large geographical domains. However, since soil moisture is not always related to screen level variables, model errors and uncertainties in the forcing data can accumulate in root zone soil moisture. Remotely sensed surface soil moisture is directly linked to the model's uppermost soil layer and therefore is a stronger constraint for the soil moisture analysis. For this study, three data assimilation experiments with the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) have been performed for the 2-month period of June and July 2002: a control run based on the operational soil moisture analysis, an open loop run with freely evolving soil moisture, and an experimental run incorporating TMI (TRMM Microwave Imager) derived soil moisture over the southern United States. In this experimental run the satellite-derived soil moisture product is introduced through a nudging scheme using 6-hourly increments. Apart from the soil moisture analysis, the system setup reflects the operational forecast configuration including the atmospheric 4D-Var analysis. Soil moisture analyzed in the nudging experiment is the most accurate estimate when compared against in situ observations from the Oklahoma Mesonet. The corresponding forecast for 2 m temperature and relative humidity is almost as accurate as in the control experiment. Furthermore, it is shown that the soil moisture analysis influences local weather parameters including the planetary boundary layer height and cloud coverage.
Numerical time integration for air pollution models
J.G. Verwer (Jan); W. Hundsdorfer (Willem); J.G. Blom (Joke)
1998-01-01
textabstractDue to the large number of chemical species and the three space dimensions, off-the-shelf stiff ODE integrators are not feasible for the numerical time integration of stiff systems of advection-diffusion-reaction equations [ fracpar{c{t + nabla cdot left( vu{u c right) = nabla cdot left(
A numerical method for resonance integral calculations
International Nuclear Information System (INIS)
Tanbay, Tayfun; Ozgener, Bilge
2013-01-01
A numerical method has been proposed for resonance integral calculations and a cubic fit based on least squares approximation to compute the optimum Bell factor is given. The numerical method is based on the discretization of the neutron slowing down equation. The scattering integral is approximated by taking into account the location of the upper limit in energy domain. The accuracy of the method has been tested by performing computations of resonance integrals for uranium dioxide isolated rods and comparing the results with empirical values. (orig.)
Numerical experiments with neural networks
International Nuclear Information System (INIS)
Miranda, Enrique.
1990-01-01
Neural networks are highly idealized models which, in spite of their simplicity, reproduce some key features of the real brain. In this paper, they are introduced at a level adequate for an undergraduate computational physics course. Some relevant magnitudes are defined and evaluated numerically for the Hopfield model and a short term memory model. (Author)
Time's arrow: A numerical experiment
Fowles, G. Richard
1994-04-01
The dependence of time's arrow on initial conditions is illustrated by a numerical example in which plane waves produced by an initial pressure pulse are followed as they are multiply reflected at internal interfaces of a layered medium. Wave interactions at interfaces are shown to be analogous to the retarded and advanced waves of point sources. The model is linear and the calculation is exact and demonstrably time reversible; nevertheless the results show most of the features expected of a macroscopically irreversible system, including the approach to the Maxwell-Boltzmann distribution, ergodicity, and concomitant entropy increase.
Automatic numerical integration methods for Feynman integrals through 3-loop
International Nuclear Information System (INIS)
De Doncker, E; Olagbemi, O; Yuasa, F; Ishikawa, T; Kato, K
2015-01-01
We give numerical integration results for Feynman loop diagrams through 3-loop such as those covered by Laporta [1]. The methods are based on automatic adaptive integration, using iterated integration and extrapolation with programs from the QUADPACK package, or multivariate techniques from the ParInt package. The Dqags algorithm from QuadPack accommodates boundary singularities of fairly general types. PARINT is a package for multivariate integration layered over MPI (Message Passing Interface), which runs on clusters and incorporates advanced parallel/distributed techniques such as load balancing among processes that may be distributed over a network of nodes. Results are included for 3-loop self-energy diagrams without IR (infra-red) or UV (ultra-violet) singularities. A procedure based on iterated integration and extrapolation yields a novel method of numerical regularization for integrals with UV terms, and is applied to a set of 2-loop self-energy diagrams with UV singularities. (paper)
Numerical simulation of hypersonic flight experiment vehicle
Yamamoto, Yukimitsu; Yoshioka, Minako; 山本 行光; 吉岡 美菜子
1994-01-01
Hypersonic aerodynamic characteristics of Hypersonic FLight EXperiment (HYFLEX vehicle were investigated by numerical simulations using Navier-Stokes CFD (Computational Fluid Dynamics) code of NAL. Numerical results were compared with experimental data obtained at Hypersonic Wind Tunnel at NAL. In order to investigate real flight aerodynamic characteristics. numerical calculations corresponding to the flight conditions suffering from maximum aero thermodynamic heating were also made and the d...
Numerical methods for engine-airframe integration
International Nuclear Information System (INIS)
Murthy, S.N.B.; Paynter, G.C.
1986-01-01
Various papers on numerical methods for engine-airframe integration are presented. The individual topics considered include: scientific computing environment for the 1980s, overview of prediction of complex turbulent flows, numerical solutions of the compressible Navier-Stokes equations, elements of computational engine/airframe integrations, computational requirements for efficient engine installation, application of CAE and CFD techniques to complete tactical missile design, CFD applications to engine/airframe integration, and application of a second-generation low-order panel methods to powerplant installation studies. Also addressed are: three-dimensional flow analysis of turboprop inlet and nacelle configurations, application of computational methods to the design of large turbofan engine nacelles, comparison of full potential and Euler solution algorithms for aeropropulsive flow field computations, subsonic/transonic, supersonic nozzle flows and nozzle integration, subsonic/transonic prediction capabilities for nozzle/afterbody configurations, three-dimensional viscous design methodology of supersonic inlet systems for advanced technology aircraft, and a user's technology assessment
The plasma focus - numerical experiments leading technology
International Nuclear Information System (INIS)
Saw, S.H.; Lee, S.
2013-01-01
Numerical experiments on the plasma focus are now used routinely to assist design and provide reference points for diagnostics. More importantly guidance has been given regarding the implementation of technology for new generations of plasma focus devices. For example intensive series of experiments have shown that it is of no use to reduce static bank inductance L0 below certain values because of the consistent loading effects of the plasma focus dynamics on the capacitor bank. Thus whilst it was thought that the PF1000 could receive major benefits by reducing its bank inductance L 0 , numerical experiments have shown to the contrary that its present L 0 of 30 nH is already optimum and that reducing L 0 would be a very expensive fruitless exercise. This knowledge gained from numerical experiments now acts as a general valuable guideline to all high performance (ie low inductance) plasma focus devices not to unnecessarily attempt to further lower the static inductance L 0 . The numerical experiments also show that the deterioration of the yield scaling law (e.g. the fusion neutron yield scaling with storage energy) is inevitable again due to the consistent loading effect of the plasma focus, which becomes more and more dominant as capacitor bank impedance reduces with increasing capacitance C 0 as storage energy is increased. This line of thinking has led to the suggestion of using higher voltages (as an alternative to increasing C 0 ) and to seeding of Deuterium with noble gases in order to enhance compression through thermodynamic mechanisms and through radiation cooling effects of strong line radiation. Circuit manipulation e.g. to enhance focus pinch compression by current-stepping is also being numerically experimented upon. Ultimately however systems have to be built, guided by numerical experiments, so that the predicted technology may be proven and realized. (author)
Soil remediation by heat injection: Experiments and numerical modelling
Energy Technology Data Exchange (ETDEWEB)
Betz, C.; Emmert, M.; Faerber, A. [Univ. of Stuttgart (Germany)] [and others
1995-03-01
In order to understand physical processes of thermally enhanced soil vapor extraction methods in porous media the isothermal, multiphase formulation for the numerical model MUFTE will be extended by a non-isothermal, multiphase-multicomponent formulation. In order to verify the numerical model, comparison with analytical solutions for well defined problems will be carried out. To identify relevant processes and their interactions, the results of the simulation will be compared with well controlled experiments with sophisticated measurement equipment in three different scales. The aim is to compare the different numerical solution techniques namely Finite Element versus Integral Finite Difference technique as implemented in MUFTE and TOUGH2 [9] respectively.
Some Experiences with Numerical Modelling of Overflows
DEFF Research Database (Denmark)
Larsen, Torben; Nielsen, L.; Jensen, B.
2007-01-01
across the edge of the overflow. To ensure critical flow across the edge, the upstream flow must be subcritical whereas the downstream flow is either supercritical or a free jet. Experimentally overflows are well studied. Based on laboratory experiments and Froude number scaling, numerous accurate...
Applying recursive numerical integration techniques for solving high dimensional integrals
International Nuclear Information System (INIS)
Ammon, Andreas; Genz, Alan; Hartung, Tobias; Jansen, Karl; Volmer, Julia; Leoevey, Hernan
2016-11-01
The error scaling for Markov-Chain Monte Carlo techniques (MCMC) with N samples behaves like 1/√(N). This scaling makes it often very time intensive to reduce the error of computed observables, in particular for applications in lattice QCD. It is therefore highly desirable to have alternative methods at hand which show an improved error scaling. One candidate for such an alternative integration technique is the method of recursive numerical integration (RNI). The basic idea of this method is to use an efficient low-dimensional quadrature rule (usually of Gaussian type) and apply it iteratively to integrate over high-dimensional observables and Boltzmann weights. We present the application of such an algorithm to the topological rotor and the anharmonic oscillator and compare the error scaling to MCMC results. In particular, we demonstrate that the RNI technique shows an error scaling in the number of integration points m that is at least exponential.
Applying recursive numerical integration techniques for solving high dimensional integrals
Energy Technology Data Exchange (ETDEWEB)
Ammon, Andreas [IVU Traffic Technologies AG, Berlin (Germany); Genz, Alan [Washington State Univ., Pullman, WA (United States). Dept. of Mathematics; Hartung, Tobias [King' s College, London (United Kingdom). Dept. of Mathematics; Jansen, Karl; Volmer, Julia [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Leoevey, Hernan [Humboldt Univ. Berlin (Germany). Inst. fuer Mathematik
2016-11-15
The error scaling for Markov-Chain Monte Carlo techniques (MCMC) with N samples behaves like 1/√(N). This scaling makes it often very time intensive to reduce the error of computed observables, in particular for applications in lattice QCD. It is therefore highly desirable to have alternative methods at hand which show an improved error scaling. One candidate for such an alternative integration technique is the method of recursive numerical integration (RNI). The basic idea of this method is to use an efficient low-dimensional quadrature rule (usually of Gaussian type) and apply it iteratively to integrate over high-dimensional observables and Boltzmann weights. We present the application of such an algorithm to the topological rotor and the anharmonic oscillator and compare the error scaling to MCMC results. In particular, we demonstrate that the RNI technique shows an error scaling in the number of integration points m that is at least exponential.
Numerical experiments on unstructured PIC stability.
Energy Technology Data Exchange (ETDEWEB)
Day, David Minot
2011-04-01
Particle-In-Cell (PIC) is a method for plasmas simulation. Particles are pushed with Verlet time integration. Fields are modeled using finite differences on a tensor product mesh (cells). The Unstructured PIC methods studied here use instead finite element discretizations on unstructured (simplicial) meshes. PIC is constrained by stability limits (upper bounds) on mesh and time step sizes. Numerical evidence (2D) and analysis will be presented showing that similar bounds constrain unstructured PIC.
Integrated optical circuits for numerical computation
Verber, C. M.; Kenan, R. P.
1983-01-01
The development of integrated optical circuits (IOC) for numerical-computation applications is reviewed, with a focus on the use of systolic architectures. The basic architecture criteria for optical processors are shown to be the same as those proposed by Kung (1982) for VLSI design, and the advantages of IOCs over bulk techniques are indicated. The operation and fabrication of electrooptic grating structures are outlined, and the application of IOCs of this type to an existing 32-bit, 32-Mbit/sec digital correlator, a proposed matrix multiplier, and a proposed pipeline processor for polynomial evaluation is discussed. The problems arising from the inherent nonlinearity of electrooptic gratings are considered. Diagrams and drawings of the application concepts are provided.
Numerical integration of asymptotic solutions of ordinary differential equations
Thurston, Gaylen A.
1989-01-01
Classical asymptotic analysis of ordinary differential equations derives approximate solutions that are numerically stable. However, the analysis also leads to tedious expansions in powers of the relevant parameter for a particular problem. The expansions are replaced with integrals that can be evaluated by numerical integration. The resulting numerical solutions retain the linear independence that is the main advantage of asymptotic solutions. Examples, including the Falkner-Skan equation from laminar boundary layer theory, illustrate the method of asymptotic analysis with numerical integration.
Experiments and Numerical Simulations of Electrodynamic Tether
Iki, Kentaro; Kawamoto, Satomi; Takahashi, Ayaka; Ishimoto, Tomori; Yanagida, Atsushi; Toda, Susumu
As an effective means of suppressing space debris growth, the Aerospace Research and Development Directorate of the Japan Aerospace Exploration Agency (JAXA) has been investigating an active space debris removal system that employs highly efficient electrodynamic tether (EDT) technology for orbital transfer. This study investigates tether deployment dynamics by means of on-ground experiments and numerical simulations of an electrodynamic tether system. Some key parameters used in the numerical simulations, such as the elastic modulus and damping ratio of the tether, the spring constant of the coiling of the tether, and deployment friction, must be estimated, and various experiments are conducted to determine these values. As a result, the following values were obtained: The elastic modulus of the tether was 40 GPa, and the damping ratio of the tether was 0.02. The spring constant and the damping ratio of the tether coiling were 10-4 N/m and 0.025 respectively. The deployment friction was 0.038ν + 0.005 N. In numerical simulations using a multiple mass tether model, tethers with lengths of several kilometers are deployed and the attitude dynamics of satellites attached to the end of the tether and tether libration are calculated. As a result, the simulations confirmed successful deployment of the tether with a length of 500 m using the electrodynamic tether system.
A Generalized Technique in Numerical Integration
Safouhi, Hassan
2018-02-01
Integration by parts is one of the most popular techniques in the analysis of integrals and is one of the simplest methods to generate asymptotic expansions of integral representations. The product of the technique is usually a divergent series formed from evaluating boundary terms; however, sometimes the remaining integral is also evaluated. Due to the successive differentiation and anti-differentiation required to form the series or the remaining integral, the technique is difficult to apply to problems more complicated than the simplest. In this contribution, we explore a generalized and formalized integration by parts to create equivalent representations to some challenging integrals. As a demonstrative archetype, we examine Bessel integrals, Fresnel integrals and Airy functions.
High speed numerical integration algorithm using FPGA | Razak ...
African Journals Online (AJOL)
Conventionally, numerical integration algorithm is executed in software and time consuming to accomplish. Field Programmable Gate Arrays (FPGAs) can be used as a much faster, very efficient and reliable alternative to implement the numerical integration algorithm. This paper proposed a hardware implementation of four ...
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
Fauzi, Ahmad
2017-11-01
Numerical computation has many pedagogical advantages: it develops analytical skills and problem-solving skills, helps to learn through visualization, and enhances physics education. Unfortunately, numerical computation is not taught to undergraduate education physics students in Indonesia. Incorporate numerical computation into the undergraduate education physics curriculum presents many challenges. The main challenges are the dense curriculum that makes difficult to put new numerical computation course and most students have no programming experience. In this research, we used case study to review how to integrate numerical computation into undergraduate education physics curriculum. The participants of this research were 54 students of the fourth semester of physics education department. As a result, we concluded that numerical computation could be integrated into undergraduate education physics curriculum using spreadsheet excel combined with another course. The results of this research become complements of the study on how to integrate numerical computation in learning physics using spreadsheet excel.
Seafloor weathering buffering climate: numerical experiments
Farahat, N. X.; Archer, D. E.; Abbot, D. S.
2013-12-01
Continental silicate weathering is widely held to consume atmospheric CO2 at a rate controlled in part by temperature, resulting in a climate-weathering feedback [Walker et al., 1981]. It has been suggested that weathering of oceanic crust of warm mid-ocean ridge flanks also has a CO2 uptake rate that is controlled by climate [Sleep and Zahnle, 2001; Brady and Gislason, 1997]. Although this effect might not be significant on present-day Earth [Caldeira, 1995], seafloor weathering may be more pronounced during snowball states [Le Hir et al., 2008], during the Archean when seafloor spreading rates were faster [Sleep and Zahnle, 2001], and on waterworld planets [Abbot et al., 2012]. Previous studies of seafloor weathering have made significant contributions using qualitative, generally one-box, models, and the logical next step is to extend this work using a spatially resolved model. For example, experiments demonstrate that seafloor weathering reactions are temperature dependent, but it is not clear whether the deep ocean temperature affects the temperature at which the reactions occur, or if instead this temperature is set only by geothermal processes. Our goal is to develop a 2-D numerical model that can simulate hydrothermal circulation and resulting alteration of oceanic basalts, and can therefore address such questions. A model of diffusive and convective heat transfer in fluid-saturated porous media simulates hydrothermal circulation through porous oceanic basalt. Unsteady natural convection is solved for using a Darcy model of porous media flow that has been extensively benchmarked. Background hydrothermal circulation is coupled to mineral reaction kinetics of basaltic alteration and hydrothermal mineral precipitation. In order to quantify seafloor weathering as a climate-weathering feedback process, this model focuses on hydrothermal reactions that influence carbon uptake as well as ocean alkalinity: silicate rock dissolution, calcium and magnesium leaching
Technology Integration Experiences of Teachers
Çoklar, Ahmet Naci; Yurdakul, Isil Kabakçi
2017-01-01
Teachers are important providers of educational sustainability. Teachers' ability to adapt themselves to rapidly developing technologies applicable to learning environments is connected with technology integration. The purpose of this study is to investigate teachers' technology integration experiences in the course of learning and teaching…
Large scale experiments as a tool for numerical model development
DEFF Research Database (Denmark)
Kirkegaard, Jens; Hansen, Erik Asp; Fuchs, Jesper
2003-01-01
Experimental modelling is an important tool for study of hydrodynamic phenomena. The applicability of experiments can be expanded by the use of numerical models and experiments are important for documentation of the validity of numerical tools. In other cases numerical tools can be applied...
Integrating spatial and numerical structure in mathematical patterning
Ni’mah, K.; Purwanto; Irawan, E. B.; Hidayanto, E.
2018-03-01
This paper reports a study monitoring the integrating spatial and numerical structure in mathematical patterning skills of 30 students grade 7th of junior high school. The purpose of this research is to clarify the processes by which learners construct new knowledge in mathematical patterning. Findings indicate that: (1) students are unable to organize the structure of spatial and numerical, (2) students were only able to organize the spatial structure, but the numerical structure is still incorrect, (3) students were only able to organize numerical structure, but its spatial structure is still incorrect, (4) students were able to organize both of the spatial and numerical structure.
Parallel Algorithm for Adaptive Numerical Integration
International Nuclear Information System (INIS)
Sujatmiko, M.; Basarudin, T.
1997-01-01
This paper presents an automation algorithm for integration using adaptive trapezoidal method. The interval is adaptively divided where the width of sub interval are different and fit to the behavior of its function. For a function f, an integration on interval [a,b] can be obtained, with maximum tolerance ε, using estimation (f, a, b, ε). The estimated solution is valid if the error is still in a reasonable range, fulfil certain criteria. If the error is big, however, the problem is solved by dividing it into to similar and independent sub problem on to separate [a, (a+b)/2] and [(a+b)/2, b] interval, i. e. ( f, a, (a+b)/2, ε/2) and (f, (a+b)/2, b, ε/2) estimations. The problems are solved in two different kinds of processor, root processor and worker processor. Root processor function ti divide a main problem into sub problems and distribute them to worker processor. The division mechanism may go further until all of the sub problem are resolved. The solution of each sub problem is then submitted to the root processor such that the solution for the main problem can be obtained. The algorithm is implemented on C-programming-base distributed computer networking system under parallel virtual machine platform
Case studies in the numerical solution of oscillatory integrals
International Nuclear Information System (INIS)
Adam, G.
1992-06-01
A numerical solution of a number of 53,249 test integrals belonging to nine parametric classes was attempted by two computer codes: EAQWOM (Adam and Nobile, IMA Journ. Numer. Anal. (1991) 11, 271-296) and DO1ANF (Mark 13, 1988) from the NAG library software. For the considered test integrals, EAQWOM was found to be superior to DO1ANF as it concerns robustness, reliability, and friendly user information in case of failure. (author). 9 refs, 3 tabs
Numerical experiment on finite element method for matching data
International Nuclear Information System (INIS)
Tokuda, Shinji; Kumakura, Toshimasa; Yoshimura, Koichi.
1993-03-01
Numerical experiments are presented on the finite element method by Pletzer-Dewar for matching data of an ordinary differential equation with regular singular points by using model equation. Matching data play an important role in nonideal MHD stability analysis of a magnetically confined plasma. In the Pletzer-Dewar method, the Frobenius series for the 'big solution', the fundamental solution which is not square-integrable at the regular singular point, is prescribed. The experiments include studies of the convergence rate of the matching data obtained by the finite element method and of the effect on the results of computation by truncating the Frobenius series at finite terms. It is shown from the present study that the finite element method is an effective method for obtaining the matching data with high accuracy. (author)
Numerical integration subprogrammes in Fortran II-D
Energy Technology Data Exchange (ETDEWEB)
Fry, C. R.
1966-12-15
This note briefly describes some integration subprogrammes written in FORTRAN II-D for the IBM 1620-II at CARDE. These presented are two Newton-Cotes, Chebyshev polynomial summation, Filon's, Nordsieck's and optimum Runge-Kutta and predictor-corrector methods. A few miscellaneous numerical integration procedures are also mentioned covering statistical functions, oscillating integrands and functions occurring in electrical engineering.
A Numerical Study of Quantization-Based Integrators
Directory of Open Access Journals (Sweden)
Barros Fernando
2014-01-01
Full Text Available Adaptive step size solvers are nowadays considered fundamental to achieve efficient ODE integration. While, traditionally, ODE solvers have been designed based on discrete time machines, new approaches based on discrete event systems have been proposed. Quantization provides an efficient integration technique based on signal threshold crossing, leading to independent and modular solvers communicating through discrete events. These solvers can benefit from the large body of knowledge on discrete event simulation techniques, like parallelization, to obtain efficient numerical integration. In this paper we introduce new solvers based on quantization and adaptive sampling techniques. Preliminary numerical results comparing these solvers are presented.
Canonical algorithms for numerical integration of charged particle motion equations
Efimov, I. N.; Morozov, E. A.; Morozova, A. R.
2017-02-01
A technique for numerically integrating the equation of charged particle motion in a magnetic field is considered. It is based on the canonical transformations of the phase space in Hamiltonian mechanics. The canonical transformations make the integration process stable against counting error accumulation. The integration algorithms contain a minimum possible amount of arithmetics and can be used to design accelerators and devices of electron and ion optics.
Numerical modeling in photonic crystals integrated technology: the COPERNICUS Project
DEFF Research Database (Denmark)
Malaguti, Stefania; Armaroli, Andrea; Bellanca, Gaetano
2011-01-01
Photonic crystals will play a fundamental role in the future of optical communications. The relevance of the numerical modeling for the success of this technology is assessed by using some examples concerning the experience of the COPERNICUS Project.......Photonic crystals will play a fundamental role in the future of optical communications. The relevance of the numerical modeling for the success of this technology is assessed by using some examples concerning the experience of the COPERNICUS Project....
Numerical calculations in elementary quantum mechanics using Feynman path integrals
International Nuclear Information System (INIS)
Scher, G.; Smith, M.; Baranger, M.
1980-01-01
We show that it is possible to do numerical calculations in elementary quantum mechanics using Feynman path integrals. Our method involves discretizing both time and space, and summing paths through matrix multiplication. We give numerical results for various one-dimensional potentials. The calculations of energy levels and wavefunctions take approximately 100 times longer than with standard methods, but there are other problems for which such an approach should be more efficient
Numerical computation of molecular integrals via optimized (vectorized) FORTRAN code
International Nuclear Information System (INIS)
Scott, T.C.; Grant, I.P.; Saunders, V.R.
1997-01-01
The calculation of molecular properties based on quantum mechanics is an area of fundamental research whose horizons have always been determined by the power of state-of-the-art computers. A computational bottleneck is the numerical calculation of the required molecular integrals to sufficient precision. Herein, we present a method for the rapid numerical evaluation of molecular integrals using optimized FORTRAN code generated by Maple. The method is based on the exploitation of common intermediates and the optimization can be adjusted to both serial and vectorized computations. (orig.)
Numerical solution of boundary-integral equations for molecular electrostatics.
Bardhan, Jaydeep P
2009-03-07
Numerous molecular processes, such as ion permeation through channel proteins, are governed by relatively small changes in energetics. As a result, theoretical investigations of these processes require accurate numerical methods. In the present paper, we evaluate the accuracy of two approaches to simulating boundary-integral equations for continuum models of the electrostatics of solvation. The analysis emphasizes boundary-element method simulations of the integral-equation formulation known as the apparent-surface-charge (ASC) method or polarizable-continuum model (PCM). In many numerical implementations of the ASC/PCM model, one forces the integral equation to be satisfied exactly at a set of discrete points on the boundary. We demonstrate in this paper that this approach to discretization, known as point collocation, is significantly less accurate than an alternative approach known as qualocation. Furthermore, the qualocation method offers this improvement in accuracy without increasing simulation time. Numerical examples demonstrate that electrostatic part of the solvation free energy, when calculated using the collocation and qualocation methods, can differ significantly; for a polypeptide, the answers can differ by as much as 10 kcal/mol (approximately 4% of the total electrostatic contribution to solvation). The applicability of the qualocation discretization to other integral-equation formulations is also discussed, and two equivalences between integral-equation methods are derived.
Numerical evaluation of tensor Feynman integrals in Euclidean kinematics
Energy Technology Data Exchange (ETDEWEB)
Gluza, J.; Kajda [Silesia Univ., Katowice (Poland). Inst. of Physics; Riemann, T.; Yundin, V. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2010-10-15
For the investigation of higher order Feynman integrals, potentially with tensor structure, it is highly desirable to have numerical methods and automated tools for dedicated, but sufficiently 'simple' numerical approaches. We elaborate two algorithms for this purpose which may be applied in the Euclidean kinematical region and in d=4-2{epsilon} dimensions. One method uses Mellin-Barnes representations for the Feynman parameter representation of multi-loop Feynman integrals with arbitrary tensor rank. Our Mathematica package AMBRE has been extended for that purpose, and together with the packages MB (M. Czakon) or MBresolve (A. V. Smirnov and V. A. Smirnov) one may perform automatically a numerical evaluation of planar tensor Feynman integrals. Alternatively, one may apply sector decomposition to planar and non-planar multi-loop {epsilon}-expanded Feynman integrals with arbitrary tensor rank. We automatized the preparations of Feynman integrals for an immediate application of the package sectordecomposition (C. Bogner and S. Weinzierl) so that one has to give only a proper definition of propagators and numerators. The efficiency of the two implementations, based on Mellin-Barnes representations and sector decompositions, is compared. The computational packages are publicly available. (orig.)
Numerical Integration of the Transport Equation For Infinite Homogeneous Media
Energy Technology Data Exchange (ETDEWEB)
Haakansson, Rune
1962-01-15
The transport equation for neutrons in infinite homogeneous media is solved by direct numerical integration. Accounts are taken to the anisotropy and the inelastic scattering. The integration has been performed by means of the trapezoidal rule and the length of the energy intervals are constant in lethargy scale. The machine used is a Ferranti Mercury computer. Results are given for water, heavy water, aluminium water mixture and iron-aluminium-water mixture.
Modelling of multidimensional quantum systems by the numerical functional integration
International Nuclear Information System (INIS)
Lobanov, Yu.Yu.; Zhidkov, E.P.
1990-01-01
The employment of the numerical functional integration for the description of multidimensional systems in quantum and statistical physics is considered. For the multiple functional integrals with respect to Gaussian measures in the full separable metric spaces the new approximation formulas exact on a class of polynomial functionals of a given summary degree are constructed. The use of the formulas is demonstrated on example of computation of the Green function and the ground state energy in multidimensional Calogero model. 15 refs.; 2 tabs
International Nuclear Information System (INIS)
Witkowski, W.R.; Eldred, M.S.; Harding, D.C.
1994-01-01
The use of state-of-the-art numerical analysis tools to determine the optimal design of a radioactive material (RAM) transportation container is investigated. The design of a RAM package's components involves a complex coupling of structural, thermal, and radioactive shielding analyses. The final design must adhere to very strict design constraints. The current technique used by cask designers is uncoupled and involves designing each component separately with respect to its driving constraint. With the use of numerical optimization schemes, the complex couplings can be considered directly, and the performance of the integrated package can be maximized with respect to the analysis conditions. This can lead to more efficient package designs. Thermal and structural accident conditions are analyzed in the shape optimization of a simplified cask design. In this paper, details of the integration of numerical analysis tools, development of a process model, nonsmoothness difficulties with the optimization of the cask, and preliminary results are discussed
Monograph - The Numerical Integration of Ordinary Differential Equations.
Hull, T. E.
The materials presented in this monograph are intended to be included in a course on ordinary differential equations at the upper division level in a college mathematics program. These materials provide an introduction to the numerical integration of ordinary differential equations, and they can be used to supplement a regular text on this…
Preserving Simplecticity in the Numerical Integration of Linear Beam Optics
Energy Technology Data Exchange (ETDEWEB)
Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2017-07-01
Presented are mathematical tools and methods for the development of numerical integration techniques that preserve the symplectic condition inherent to mechanics. The intended audience is for beam physicists with backgrounds in numerical modeling and simulation with particular attention to beam optics applications. The paper focuses on Lie methods that are inherently symplectic regardless of the integration accuracy order. Section 2 provides the mathematically tools used in the sequel and necessary for the reader to extend the covered techniques. Section 3 places those tools in the context of charged-particle beam optics; in particular linear beam optics is presented in terms of a Lie algebraic matrix representation. Section 4 presents numerical stepping techniques with particular emphasis on a third-order leapfrog method. Section 5 discusses the modeling of field imperfections with particular attention to the fringe fields of quadrupole focusing magnets. The direct computation of a third order transfer matrix for a fringe field is shown.
INTEGRATION POLICY TOWARDS IMMIGRANTS: CURRENT EXPERIENCE
Directory of Open Access Journals (Sweden)
Nadiia Bureiko
2012-03-01
Full Text Available In the contemporary world the intensity of the immigration movements is constantly increasing. Countries which experience great immigrant flows are facing numerous problems which should be solved. The article studies the current immigration flows in EU countries, the United States of America and Canada and presents three main models of integration policy towards immigrants – political assimilation, functional integration and multicultural model. Separate models are distinguished for the Muslims’ integration. The author examines the peculiarities of every model and examines the conclusions provided by the Migrant Integration Policy Index (MIPEX concerning the situation of the immigrants’ integration in 31 countries in 2011. Among all the policy indicators the first that are defined are as follows: political participation, education, labour market mobility and anti-discrimination. The situation with immigrants’ integration in Ukraine is also studied as it is gaining a great attention of the authorities and the public. The measures and practical steps done regarding this situation in Ukraine in recent years are analyzed using the information offered by the State Migration Service of Ukraine.
Symbolic-Numeric Integration of the Dynamical Cosserat Equations
Lyakhov, Dmitry A.
2017-08-29
We devise a symbolic-numeric approach to the integration of the dynamical part of the Cosserat equations, a system of nonlinear partial differential equations describing the mechanical behavior of slender structures, like fibers and rods. This is based on our previous results on the construction of a closed form general solution to the kinematic part of the Cosserat system. Our approach combines methods of numerical exponential integration and symbolic integration of the intermediate system of nonlinear ordinary differential equations describing the dynamics of one of the arbitrary vector-functions in the general solution of the kinematic part in terms of the module of the twist vector-function. We present an experimental comparison with the well-established generalized \\\\alpha -method illustrating the computational efficiency of our approach for problems in structural mechanics.
Symbolic-Numeric Integration of the Dynamical Cosserat Equations
Lyakhov, Dmitry A.; Gerdt, Vladimir P.; Weber, Andreas G.; Michels, Dominik L.
2017-01-01
We devise a symbolic-numeric approach to the integration of the dynamical part of the Cosserat equations, a system of nonlinear partial differential equations describing the mechanical behavior of slender structures, like fibers and rods. This is based on our previous results on the construction of a closed form general solution to the kinematic part of the Cosserat system. Our approach combines methods of numerical exponential integration and symbolic integration of the intermediate system of nonlinear ordinary differential equations describing the dynamics of one of the arbitrary vector-functions in the general solution of the kinematic part in terms of the module of the twist vector-function. We present an experimental comparison with the well-established generalized \\alpha -method illustrating the computational efficiency of our approach for problems in structural mechanics.
Microwave Breast Imaging System Prototype with Integrated Numerical Characterization
Directory of Open Access Journals (Sweden)
Mark Haynes
2012-01-01
Full Text Available The increasing number of experimental microwave breast imaging systems and the need to properly model them have motivated our development of an integrated numerical characterization technique. We use Ansoft HFSS and a formalism we developed previously to numerically characterize an S-parameter- based breast imaging system and link it to an inverse scattering algorithm. We show successful reconstructions of simple test objects using synthetic and experimental data. We demonstrate the sensitivity of image reconstructions to knowledge of the background dielectric properties and show the limits of the current model.
Numerical treatments for solving nonlinear mixed integral equation
Directory of Open Access Journals (Sweden)
M.A. Abdou
2016-12-01
Full Text Available We consider a mixed type of nonlinear integral equation (MNLIE of the second kind in the space C[0,T]×L2(Ω,T<1. The Volterra integral terms (VITs are considered in time with continuous kernels, while the Fredholm integral term (FIT is considered in position with singular general kernel. Using the quadratic method and separation of variables method, we obtain a nonlinear system of Fredholm integral equations (NLSFIEs with singular kernel. A Toeplitz matrix method, in each case, is then used to obtain a nonlinear algebraic system. Numerical results are calculated when the kernels take a logarithmic form or Carleman function. Moreover, the error estimates, in each case, are then computed.
Implementation of a revised numerical integration technique into QAD
International Nuclear Information System (INIS)
De Gangi, N.L.
1983-01-01
A technique for numerical integration through a uniform volume source is developed. It is applied to gamma radiation transport shielding problems. The method is based on performing a numerical angular and ray point kernel integration and is incorporated into the QAD-CG computer code (i.e. QAD-UE). Several test problems are analyzed with this technique. Convergence properties of the method are analyzed. Gamma dose rates from a large tank and post LOCA dose rates inside a containment building are evaluated. Results are consistent with data from other methods. The new technique provides several advantages. User setup requirements for large volume source problems are reduced from standard point kernel requirements. Calculational efficiencies are improved. An order of magnitude improvement is seen with a test problem
Application of symplectic integrator to numerical fluid analysis
International Nuclear Information System (INIS)
Tanaka, Nobuatsu
2000-01-01
This paper focuses on application of the symplectic integrator to numerical fluid analysis. For the purpose, we introduce Hamiltonian particle dynamics to simulate fluid behavior. The method is based on both the Hamiltonian formulation of a system and the particle methods, and is therefore called Hamiltonian Particle Dynamics (HPD). In this paper, an example of HPD applications, namely the behavior of incompressible inviscid fluid, is solved. In order to improve accuracy of HPD with respect to space, CIVA, which is a highly accurate interpolation method, is combined, but the combined method is subject to problems in that the invariants of the system are not conserved in a long-time computation. For solving the problems, symplectic time integrators are introduced and the effectiveness is confirmed by numerical analyses. (author)
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)
Loop integration results using numerical extrapolation for a non-scalar integral
International Nuclear Information System (INIS)
Doncker, E. de; Shimizu, Y.; Fujimoto, J.; Yuasa, F.; Kaugars, K.; Cucos, L.; Van Voorst, J.
2004-01-01
Loop integration results have been obtained using numerical integration and extrapolation. An extrapolation to the limit is performed with respect to a parameter in the integrand which tends to zero. Results are given for a non-scalar four-point diagram. Extensions to accommodate loop integration by existing integration packages are also discussed. These include: using previously generated partitions of the domain and roundoff error guards
Free and constrained symplectic integrators for numerical general relativity
International Nuclear Information System (INIS)
Richter, Ronny; Lubich, Christian
2008-01-01
We consider symplectic time integrators in numerical general relativity and discuss both free and constrained evolution schemes. For free evolution of ADM-like equations we propose the use of the Stoermer-Verlet method, a standard symplectic integrator which here is explicit in the computationally expensive curvature terms. For the constrained evolution we give a formulation of the evolution equations that enforces the momentum constraints in a holonomically constrained Hamiltonian system and turns the Hamilton constraint function from a weak to a strong invariant of the system. This formulation permits the use of the constraint-preserving symplectic RATTLE integrator, a constrained version of the Stoermer-Verlet method. The behavior of the methods is illustrated on two effectively (1+1)-dimensional versions of Einstein's equations, which allow us to investigate a perturbed Minkowski problem and the Schwarzschild spacetime. We compare symplectic and non-symplectic integrators for free evolution, showing very different numerical behavior for nearly-conserved quantities in the perturbed Minkowski problem. Further we compare free and constrained evolution, demonstrating in our examples that enforcing the momentum constraints can turn an unstable free evolution into a stable constrained evolution. This is demonstrated in the stabilization of a perturbed Minkowski problem with Dirac gauge, and in the suppression of the propagation of boundary instabilities into the interior of the domain in Schwarzschild spacetime
Mechanical Interaction in Pressurized Pipe Systems: Experiments and Numerical Models
Directory of Open Access Journals (Sweden)
Mariana Simão
2015-11-01
Full Text Available The dynamic interaction between the unsteady flow occurrence and the resulting vibration of the pipe are analyzed based on experiments and numerical models. Waterhammer, structural dynamic and fluid–structure interaction (FSI are the main subjects dealt with in this study. Firstly, a 1D model is developed based on the method of characteristics (MOC using specific damping coefficients for initial components associated with rheological pipe material behavior, structural and fluid deformation, and type of anchored structural supports. Secondly a 3D coupled complex model based on Computational Fluid Dynamics (CFD, using a Finite Element Method (FEM, is also applied to predict and distinguish the FSI events. Herein, a specific hydrodynamic model of viscosity to replicate the operation of a valve was also developed to minimize the number of mesh elements and the complexity of the system. The importance of integrated analysis of fluid–structure interaction, especially in non-rigidity anchored pipe systems, is equally emphasized. The developed models are validated through experimental tests.
Numerical integration of massive two-loop Mellin-Barnes integrals in Minkowskian regions
International Nuclear Information System (INIS)
Dubovyk, Ievgen
2016-07-01
Mellin-Barnes (MB) techniques applied to integrals emerging in particle physics perturbative calculations are summarized. New versions of AMBRE packages which construct planar and nonplanar MB representations are shortly discussed. The numerical package MBnumerics.m is presented for the first time which is able to calculate with a high precision multidimensional MB integrals in Minkowskian regions. Examples are given for massive vertex integrals which include threshold effects and several scale parameters.
Numerical integration of massive two-loop Mellin-Barnes integrals in Minkowskian regions
Energy Technology Data Exchange (ETDEWEB)
Dubovyk, Ievgen [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Gluza, Janusz [Uniwersytet Slaski, Katowice (Poland). Inst. Fizyki; Riemann, Tord [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Uniwersytet Slaski, Katowice (Poland). Inst. Fizyki; Usovitsch, Johann [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2016-07-15
Mellin-Barnes (MB) techniques applied to integrals emerging in particle physics perturbative calculations are summarized. New versions of AMBRE packages which construct planar and nonplanar MB representations are shortly discussed. The numerical package MBnumerics.m is presented for the first time which is able to calculate with a high precision multidimensional MB integrals in Minkowskian regions. Examples are given for massive vertex integrals which include threshold effects and several scale parameters.
Numerical integration of some new unified plasticity-creep formulations
International Nuclear Information System (INIS)
Krieg, R.D.
1977-01-01
The unified formulations seem to lead to very non-linear systems of equations which are very well behaved in some regions and very stiff in other regions where the word 'stiff' is used in the mathematical sense. Simple conventional methods of integrating incremental constitutive equations are observed to be totally inadequate. A method of numerically integrating the equations is presented. Automatic step size determination based on accuracy and stability is a necessary expense. In the region where accuracy is the limiting condition the equations can be integrated directly. A forward Euler predictor with a trapezoidal corrector is used in the paper. In the region where stability is the limiting condition, direct integration methods become inefficient and an implicit integrator which is suited to stiff equations must be used. A backward Euler method is used in the paper. It is implemented with a Picard iteration method in which a Newton method is used to predict inelastic strainrate and speed convergence in a Newton-Raphson manner. This allows an analytic expression for the Jacobian to be used, where a full Newton-Raphson would require a numerical approximation to the Jacobian. The starting procedure for the iteration is an adaptation of time independent plasticity ideas. Because of the inherent capability of the unified plasticity-creep formulations, it is felt that these theories will become accepted in the metallurgical community. Structural analysts will then be required to incorporate these formulations and must be prepared to face the difficult implementation inherent in these models. This paper is an attempt to shed some light on the difficulties and expenses involved
International Nuclear Information System (INIS)
Emoto, M.; Suzuki, C.; Suzuki, Y.; Yokoyama, M.; Seki, R.; Ida, K.
2014-10-01
The enhanced-interlink system of experiment data and numerical simulation has been developed, and successfully operated routinely in the Large Helical Device (LHD). This system consists of analyzed diagnostic data, real-time coordinate mapping, and automatic data processing. It has enabled automated data handling/transferring between experiment and numerical simulation, to extensively perform experiment analyses. It can be considered as one of the prototypes for a seamless data-centric approach for integrating experiment data and numerical simulation/modellings in fusion experiments. Utilizing this system, experimental analyses by numerical simulations have extensively progressed. The authors believe this data-centric approach for integrating experiment data and numerical simulation/modellings will contribute to not only the LHD but to other plasma fusion projects including DEMO reactor in the future. (author)
Comparison of GPU-Based Numerous Particles Simulation and Experiment
International Nuclear Information System (INIS)
Park, Sang Wook; Jun, Chul Woong; Sohn, Jeong Hyun; Lee, Jae Wook
2014-01-01
The dynamic behavior of numerous grains interacting with each other can be easily observed. In this study, this dynamic behavior was analyzed based on the contact between numerous grains. The discrete element method was used for analyzing the dynamic behavior of each particle and the neighboring-cell algorithm was employed for detecting their contact. The Hertzian and tangential sliding friction contact models were used for calculating the contact force acting between the particles. A GPU-based parallel program was developed for conducting the computer simulation and calculating the numerous contacts. The dam break experiment was performed to verify the simulation results. The reliability of the program was verified by comparing the results of the simulation with those of the experiment
Agglomeration processes in carbonaceous dusty plasmas, experiments and numerical simulations
International Nuclear Information System (INIS)
Dap, S; Hugon, R; De Poucques, L; Bougdira, J; Lacroix, D; Patisson, F
2010-01-01
This paper deals with carbon dust agglomeration in radio frequency acetylene/argon plasma. Two studies, an experimental and a numerical one, were carried out to model dust formation mechanisms. Firstly, in situ transmission spectroscopy of dust clouds in the visible range was performed in order to observe the main features of the agglomeration process of the produced carbonaceous dust. Secondly, numerical simulation tools dedicated to understanding the achieved experiments were developed. A first model was used for the discretization of the continuous population balance equations that characterize the dust agglomeration process. The second model is based on a Monte Carlo ray-tracing code coupled to a Mie theory calculation of dust absorption and scattering parameters. These two simulation tools were used together in order to numerically predict the light transmissivity through a dusty plasma and make comparisons with experiments.
Numerical counting ratemeter with variable time constant and integrated circuits
International Nuclear Information System (INIS)
Kaiser, J.; Fuan, J.
1967-01-01
We present here the prototype of a numerical counting ratemeter which is a special version of variable time-constant frequency meter (1). The originality of this work lies in the fact that the change in the time constant is carried out automatically. Since the criterion for this change is the accuracy in the annunciated result, the integration time is varied as a function of the frequency. For the prototype described in this report, the time constant varies from 1 sec to 1 millisec. for frequencies in the range 10 Hz to 10 MHz. This prototype is built entirely of MECL-type integrated circuits from Motorola and is thus contained in two relatively small boxes. (authors) [fr
Numerical experiments using deflation with the HISQ action
Davies, Christine; DeTar, Carleton; McNeile, Craig; Vaquero, Alejandro
2018-03-01
We report on numerical experiments using deflation to compute quark propagators for the highly improved staggered quark (HISQ) action. The method is tested on HISQ gauge configurations, generated by the MILC collaboration, with lattice spacings of 0.15 fm, with a range of volumes, and sea quark masses down to the physical quark mass.
Numerical experiments with rubble piles : equilibrium shapes and spins
Richardson, Derek C.; Elankumaran, Pradeep; Sanderson, Robyn E.
2005-01-01
We present numerical experiments investigating the shape and spin limits of self-gravitating "perfect" rubble piles that consist of identical, smooth, rigid, spherical particles with configurable normal coefficient of restitution and no sliding friction. Such constructs are currently employed in a
Reimers, Marcel; Lang, Walter; Dumstorff, Gerrit
2017-09-30
The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.
Directory of Open Access Journals (Sweden)
Marcel Reimers
2017-09-01
Full Text Available The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.
Numerical modeling of the 2017 active seismic infrasound balloon experiment
Brissaud, Q.; Komjathy, A.; Garcia, R.; Cutts, J. A.; Pauken, M.; Krishnamoorthy, S.; Mimoun, D.; Jackson, J. M.; Lai, V. H.; Kedar, S.; Levillain, E.
2017-12-01
We have developed a numerical tool to propagate acoustic and gravity waves in a coupled solid-fluid medium with topography. It is a hybrid method between a continuous Galerkin and a discontinuous Galerkin method that accounts for non-linear atmospheric waves, visco-elastic waves and topography. We apply this method to a recent experiment that took place in the Nevada desert to study acoustic waves from seismic events. This experiment, developed by JPL and its partners, wants to demonstrate the viability of a new approach to probe seismic-induced acoustic waves from a balloon platform. To the best of our knowledge, this could be the only way, for planetary missions, to perform tomography when one faces challenging surface conditions, with high pressure and temperature (e.g. Venus), and thus when it is impossible to use conventional electronics routinely employed on Earth. To fully demonstrate the effectiveness of such a technique one should also be able to reconstruct the observed signals from numerical modeling. To model the seismic hammer experiment and the subsequent acoustic wave propagation, we rely on a subsurface seismic model constructed from the seismometers measurements during the 2017 Nevada experiment and an atmospheric model built from meteorological data. The source is considered as a Gaussian point source located at the surface. Comparison between the numerical modeling and the experimental data could help future mission designs and provide great insights into the planet's interior structure.
Processing biobased polymers using plasticizers: Numerical simulations versus experiments
Desplentere, Frederik; Cardon, Ludwig; Six, Wim; Erkoç, Mustafa
2016-03-01
In polymer processing, the use of biobased products shows lots of possibilities. Considering biobased materials, biodegradability is in most cases the most important issue. Next to this, bio based materials aimed at durable applications, are gaining interest. Within this research, the influence of plasticizers on the processing of the bio based material is investigated. This work is done for an extrusion grade of PLA, Natureworks PLA 2003D. Extrusion through a slit die equipped with pressure sensors is used to compare the experimental pressure values to numerical simulation results. Additional experimental data (temperature and pressure data along the extrusion screw and die are recorded) is generated on a dr. Collin Lab extruder producing a 25mm diameter tube. All these experimental data is used to indicate the appropriate functioning of the numerical simulation tool Virtual Extrusion Laboratory 6.7 for the simulation of both the industrial available extrusion grade PLA and the compound in which 15% of plasticizer is added. Adding the applied plasticizer, resulted in a 40% lower pressure drop over the extrusion die. The combination of different experiments allowed to fit the numerical simulation results closely to the experimental values. Based on this experience, it is shown that numerical simulations also can be used for modified bio based materials if appropriate material and process data are taken into account.
Integrated numerical modeling of a laser gun injector
International Nuclear Information System (INIS)
Liu, H.; Benson, S.; Bisognano, J.; Liger, P.; Neil, G.; Neuffer, D.; Sinclair, C.; Yunn, B.
1993-06-01
CEBAF is planning to incorporate a laser gun injector into the linac front end as a high-charge cw source for a high-power free electron laser and nuclear physics. This injector consists of a DC laser gun, a buncher, a cryounit and a chicane. The performance of the injector is predicted based on integrated numerical modeling using POISSON, SUPERFISH and PARMELA. The point-by-point method incorporated into PARMELA by McDonald is chosen for space charge treatment. The concept of ''conditioning for final bunching'' is employed to vary several crucial parameters of the system for achieving highest peak current while maintaining low emittance and low energy spread. Extensive parameter variation studies show that the design will perform beyond the specifications for FEL operations aimed at industrial applications and fundamental scientific research. The calculation also shows that the injector will perform as an extremely bright cw electron source
Time delay systems theory, numerics, applications, and experiments
Ersal, Tulga; Orosz, Gábor
2017-01-01
This volume collects contributions related to selected presentations from the 12th IFAC Workshop on Time Delay Systems, Ann Arbor, June 28-30, 2015. The included papers present novel techniques and new results of delayed dynamical systems. The topical spectrum covers control theory, numerical analysis, engineering and biological applications as well as experiments and case studies. The target audience primarily comprises research experts in the field of time delay systems, but the book may also be beneficial for graduate students alike. .
Numerical integration of some new unified plasticity-creep formulations
International Nuclear Information System (INIS)
Krieg, R.D.
1977-01-01
The usual constitutive description of metals at high temperature treats creep as a phenomenon which must be added to time independent phenomena. A new approach is now being advocated by some people, principally metallurgists. They all treat the inelastic strain as a unified quantity, incapable of being separated into time dependent and time independent parts. This paper examines the behavior of the differential formulations reported in the literature together with one proposed by the author. These formulations are capable of representing primary and secondary creep, cyclic hardening to a stable cyclic stress-strain loop, a conventional plasticity behavior, and a Bauchinger effect which may be creep induced and discernable either at fast or slow loading rates. The new unified formulations seem to lead to very non-linear systems of equations which are very well behaved in some regions and very stiff in other regions where the word 'stiff' is used in the mathematical sense. Simple conventional methods of integrating incremental constitutive equations are observed to be totally inadequate. A method of numerically integrating the equations is presented. (Auth.)
Reinen, L. A.; Brenner, K.
2017-12-01
Ongoing efforts to improve undergraduate education in science, technology, engineering, and mathematics (STEM) fields focus on increasing active student participation and decreasing traditional lecture-based teaching. Undergraduate research experiences (UREs), which engage students in the work of STEM professionals, are an example of these efforts. A recent report from the National Academies of Sciences, Engineering and Medicine (Undergraduate Research Experiences for STEM Students: Successes, Challenges, and Opportunities; 2017) provides characteristics of UREs, and indicates that participation in UREs increases student interest and persistence in STEM as well as provides opportunities to broaden student participation in these fields. UREs offer an excellent opportunity to engage students in research using the rapidly evolving technologies used by STEM professionals. In the fall of 2016, students in the Tectonic Landscapes class at Pomona College participated in a course-based URE that combined traditional field mapping methods with analysis of high-resolution topographic data (LiDAR) and 3D numerical modeling to investigate questions of active local faulting. During the first ten weeks students developed skills in: creation of fault maps from both field observations (GPS included) and high-resolution digital elevation models (DEMs), assessment of tectonic activity through analyses of DEMs of hill slope diffusion models and geomorphic indices, and evaluation of fault geometry hypotheses via 3D elastic modeling. Most of these assignments were focused on a single research site. While students primarily used Excel, ArcMap, and Poly3D, no previous knowledge of these was required or assumed. Through this iterative approach, students used increasingly more complex methods as well as gained greater ownership of the research process with time. The course culminated with a 4-week independent research project in which each student investigated a question of their own
Advances in Integrated Vehicle Thermal Management and Numerical Simulation
Directory of Open Access Journals (Sweden)
Yan Wang
2017-10-01
Full Text Available With the increasing demands for vehicle dynamic performance, economy, safety and comfort, and with ever stricter laws concerning energy conservation and emissions, vehicle power systems are becoming much more complex. To pursue high efficiency and light weight in automobile design, the power system and its vehicle integrated thermal management (VITM system have attracted widespread attention as the major components of modern vehicle technology. Regarding the internal combustion engine vehicle (ICEV, its integrated thermal management (ITM mainly contains internal combustion engine (ICE cooling, turbo-charged cooling, exhaust gas recirculation (EGR cooling, lubrication cooling and air conditioning (AC or heat pump (HP. As for electric vehicles (EVs, the ITM mainly includes battery cooling/preheating, electric machines (EM cooling and AC or HP. With the rational effective and comprehensive control over the mentioned dynamic devices and thermal components, the modern VITM can realize collaborative optimization of multiple thermodynamic processes from the aspect of system integration. Furthermore, the computer-aided calculation and numerical simulation have been the significant design methods, especially for complex VITM. The 1D programming can correlate multi-thermal components and the 3D simulating can develop structuralized and modularized design. Additionally, co-simulations can virtualize simulation of various thermo-hydraulic behaviors under the vehicle transient operational conditions. This article reviews relevant researching work and current advances in the ever broadening field of modern vehicle thermal management (VTM. Based on the systematic summaries of the design methods and applications of ITM, future tasks and proposals are presented. This article aims to promote innovation of ITM, strengthen the precise control and the performance predictable ability, furthermore, to enhance the level of research and development (R&D.
Tritium release experiments with CATS and numerical simulation
International Nuclear Information System (INIS)
Munakata, Kenzo; Wajima, Takaaki; Hara, Keisuke; Wada, Kohei; Takeishi, Toshiharu; Shinozaki, Yohei; Mochizuki, Kazuhiro; Katekari, Kenichi; Kobayashi, Kazuhiro; Iwai, Yasunori; Hayashi, Takumi; Yamanishi, Toshihiko
2010-01-01
In D-T fusion power plants, large amounts of tritium would be handled. Tritium is the radioisotope of protium, and is easily taken into the human body, and thus the behavior of tritium accidentally released in fusion power plants should be studied for the safety design and radioprotection of workers. Therefore, it is necessary to investigate the behavior of tritium released into large rooms with objectives, since complex flow fields should exist in such rooms and they could influence the ventilation of the air containing released tritium. Thus, tritium release experiments were conducted using Caisson Assembly for Tritium Safety Study (CATS) in TPL/JAEA. Some data were taken for tritium behavior in the ventilated area and response of tritium monitors. In the experiments, approximately 17 GBq of tritium was released into Caisson with the total volume of 12 m 3 , and the room was ventilated at the rate of 12 m 3 /h after release of tritium. It was found that placement of an objective in the vessel substantially affects decontamination efficiency. With regard to an experimental result, numerical calculation was performed and the experimental result and the result of numerical calculation were compared, which indicates that experimental results are qualitatively reproduced by numerical calculation. However, further R and D needs to be carried out for quantitative reproduction of the experimental results.
Tritium release experiments with CATS and numerical simulation
Energy Technology Data Exchange (ETDEWEB)
Munakata, Kenzo, E-mail: kenzo@gipc.akita-u.ac.jp [Faculty of Engineering and Resource Sciences, Akita University, Tegata-gakuen-cho 1-1, Akita 010-8502 (Japan); Wajima, Takaaki; Hara, Keisuke; Wada, Kohei [Faculty of Engineering and Resource Sciences, Akita University, Tegata-gakuen-cho 1-1, Akita 010-8502 (Japan); Takeishi, Toshiharu; Shinozaki, Yohei; Mochizuki, Kazuhiro; Katekari, Kenichi [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581 (Japan); Kobayashi, Kazuhiro; Iwai, Yasunori; Hayashi, Takumi; Yamanishi, Toshihiko [Tritium Technology Group, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)
2010-12-15
In D-T fusion power plants, large amounts of tritium would be handled. Tritium is the radioisotope of protium, and is easily taken into the human body, and thus the behavior of tritium accidentally released in fusion power plants should be studied for the safety design and radioprotection of workers. Therefore, it is necessary to investigate the behavior of tritium released into large rooms with objectives, since complex flow fields should exist in such rooms and they could influence the ventilation of the air containing released tritium. Thus, tritium release experiments were conducted using Caisson Assembly for Tritium Safety Study (CATS) in TPL/JAEA. Some data were taken for tritium behavior in the ventilated area and response of tritium monitors. In the experiments, approximately 17 GBq of tritium was released into Caisson with the total volume of 12 m{sup 3}, and the room was ventilated at the rate of 12 m{sup 3}/h after release of tritium. It was found that placement of an objective in the vessel substantially affects decontamination efficiency. With regard to an experimental result, numerical calculation was performed and the experimental result and the result of numerical calculation were compared, which indicates that experimental results are qualitatively reproduced by numerical calculation. However, further R and D needs to be carried out for quantitative reproduction of the experimental results.
Semi-Numerical Studies of the Three-Meter Spherical Couette Experiment Utilizing Data Assimilation
Burnett, Sarah; Rojas, Ruben; Perevalov, Artur; Lathrop, Daniel; Ide, Kayo; Schaeffer, Nathanael
2017-11-01
The model of the Earth's magnetic field has been investigated in recent years through experiments and numerical models. At the University of Maryland, experimental studies are implemented in a three-meter spherical Couette device filled with liquid sodium. The inner and outer spheres of this apparatus mimic the planet's inner core and core-mantle boundary, respectively. These experiments incorporate high velocity flows with Reynolds numbers 108 . In spherical Couette geometry, the numerical scheme applied to this work features finite difference methods in the radial direction and pseudospectral spherical harmonic transforms elsewhere. Adding to the numerical model, data assimilation integrates the experimental outer-layer magnetic field measurements. This semi-numerical model can then be compared to the experimental results as well as forecasting magnetic field changes. Data assimilation makes it possible to get estimates of internal motions of the three-meter experiment that would otherwise be intrusive or impossible to obtain in experiments or too computationally expensive with a purely numerical code. If we can provide accurate models of the three-meter device, it is possible to attempt to model the geomagnetic field. We gratefully acknowledge the support of NSF Grant No. EAR1417148 & DGE1322106.
Semi-Numerical Studies of the Three-Meter Spherical Couette Experiment Utilizing Data Assimilation
Burnett, S. C.; Rojas, R.; Perevalov, A.; Lathrop, D. P.
2017-12-01
The model of the Earth's magnetic field has been investigated in recent years through experiments and numerical models. At the University of Maryland, experimental studies are implemented in a three-meter spherical Couette device filled with liquid sodium. The inner and outer spheres of this apparatus mimic the planet's inner core and core-mantle boundary, respectively. These experiments incorporate high velocity flows with Reynolds numbers 108. In spherical Couette geometry, the numerical scheme applied to this work features finite difference methods in the radial direction and pseudospectral spherical harmonic transforms elsewhere [Schaeffer, N. G3 (2013)]. Adding to the numerical model, data assimilation integrates the experimental outer-layer magnetic field measurements. This semi-numerical model can then be compared to the experimental results as well as forecasting magnetic field changes. Data assimilation makes it possible to get estimates of internal motions of the three-meter experiment that would otherwise be intrusive or impossible to obtain in experiments or too computationally expensive with a purely numerical code. If we can provide accurate models of the three-meter device, it is possible to attempt to model the geomagnetic field. We gratefully acknowledge the support of NSF Grant No. EAR1417148 & DGE1322106.
Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices
Directory of Open Access Journals (Sweden)
Sing Lee
2010-04-01
Full Text Available Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1 a plasma current limitation effect, as device static inductance is reduced towards very small values; (2 scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3 a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron ‘saturation’; and (4 a fundamental cause of neutron ‘saturation’. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research.
Numerical simulation and experimental research of the integrated high-power LED radiator
Xiang, J. H.; Zhang, C. L.; Gan, Z. J.; Zhou, C.; Chen, C. G.; Chen, S.
2017-01-01
The thermal management has become an urgent problem to be solved with the increasing power and the improving integration of the LED (light emitting diode) chip. In order to eliminate the contact resistance of the radiator, this paper presented an integrated high-power LED radiator based on phase-change heat transfer, which realized the seamless connection between the vapor chamber and the cooling fins. The radiator was optimized by combining the numerical simulation and the experimental research. The effects of the chamber diameter and the parameters of fin on the heat dissipation performance were analyzed. The numerical simulation results were compared with the measured values by experiment. The results showed that the fin thickness, the fin number, the fin height and the chamber diameter were the factors which affected the performance of radiator from primary to secondary.
How to integrate divergent integrals: a pure numerical approach to complex loop calculations
International Nuclear Information System (INIS)
Caravaglios, F.
2000-01-01
Loop calculations involve the evaluation of divergent integrals. Usually [G. 't Hooft, M. Veltman, Nucl. Phys. B 44 (1972) 189] one computes them in a number of dimensions different than four where the integral is convergent and then one performs the analytical continuation and considers the Laurent expansion in powers of ε=n-4. In this paper we discuss a method to extract directly all coefficients of this expansion by means of concrete and well defined integrals in a five-dimensional space. We by-pass the formal and symbolic procedure of analytic continuation; instead we can numerically compute the integrals to extract directly both the coefficient of the pole 1/ε and the finite part
Numerical modeling of NI-monitored 3D infiltration experiment
Dohnal, Michal; Dusek, Jaromir; Snehota, Michal; Sacha, Jan; Vogel, Tomas; Votrubova, Jana
2014-05-01
It is well known that the temporal changes of saturated hydraulic conductivity caused by the occurrence of air phase discontinuities often play an important role in water flow and solute transport experiments. In the present study, a series of infiltration-outflow experiments was conducted to test several working hypotheses about the mechanism of air phase trapping. The experiments were performed on a porous sample with artificial internal structure, using three sandy materials with contrasting hydraulic properties. The sample was axially symmetric with continuous preferential pathways and separate porous matrix blocks (the sample was 3.4 cm in diameter and 8.8 cm high). The infiltration experiments were monitored by neutron imaging (NI). The NI data were then used to quantify the water content of the selected sample regions. The flow regime in the sample was studied using a three-dimensional model based on Richards' equation. The equation was solved by the finite element method. The results of the numerical simulations of the infiltration experiments were compared with the measured outflow rates and with the spatial distribution of water content determined by NI. The research was supported by the Czech Science Foundation Project No. 14-03691S.
Numerical solution of integral equations, describing mass spectrum of vector mesons
International Nuclear Information System (INIS)
Zhidkov, E.P.; Nikonov, E.G.; Sidorov, A.V.; Skachkov, N.B.; Khoromskij, B.N.
1988-01-01
The description of the numerical algorithm for solving quasipotential integral equation in impulse space is presented. The results of numerical computations of the vector meson mass spectrum and the leptonic decay width are given in comparison with the experimental data
GPFS HPSS Integration: Implementation Experience
Energy Technology Data Exchange (ETDEWEB)
Hazen, Damian; Hick, Jason
2008-08-12
In 2005 NERSC and IBM Global Services Federal began work to develop an integrated HSM solution using the GPFS file system and the HPSS hierarchical storage system. It was foreseen that this solution would play a key role in data management at NERSC, and fill a market niche for IBM. As with many large and complex software projects, there were a number of unforeseen difficulties encountered during implementation. As the effort progressed, it became apparent that DMAPI alone could not be used to tie two distributed, high performance systems together without serious impact on performance. This document discusses the evolution of the development effort, from one which attempted to synchronize the GPFS and HPSS name spaces relying solely on GPFS?s implementation of the DMAPI specification, to one with a more traditional HSM functionality that had no synchronized namespace in HPSS, and finally to an effort, still underway, which will provide traditional HSM functionality, but requires features from the GPFS Information Lifecycle Management (ILM) to fully achieve this goal in a way which is scalable and meets the needs of sites with aggressive performance requirements. The last approach makes concessions to portability by using file system features such as ILM and snapshotting in order to achieve a scalable design.
Carbon Dioxide Dispersion in the Combustion Integrated Rack Simulated Numerically
Wu, Ming-Shin; Ruff, Gary A.
2004-01-01
When discharged into an International Space Station (ISS) payload rack, a carbon dioxide (CO2) portable fire extinguisher (PFE) must extinguish a fire by decreasing the oxygen in the rack by 50 percent within 60 sec. The length of time needed for this oxygen reduction throughout the rack and the length of time that the CO2 concentration remains high enough to prevent the fire from reigniting is important when determining the effectiveness of the response and postfire procedures. Furthermore, in the absence of gravity, the local flow velocity can make the difference between a fire that spreads rapidly and one that self-extinguishes after ignition. A numerical simulation of the discharge of CO2 from PFE into the Combustion Integrated Rack (CIR) in microgravity was performed to obtain the local velocity and CO2 concentration. The complicated flow field around the PFE nozzle exits was modeled by sources of equivalent mass and momentum flux at a location downstream of the nozzle. The time for the concentration of CO2 to reach a level that would extinguish a fire anywhere in the rack was determined using the Fire Dynamics Simulator (FDS), a computational fluid dynamics code developed by the National Institute of Standards and Technology specifically to evaluate the development of a fire and smoke transport. The simulation shows that CO2, as well as any smoke and combustion gases produced by a fire, would be discharged into the ISS cabin through the resource utility panel at the bottom of the rack. These simulations will be validated by comparing the results with velocity and CO2 concentration measurements obtained during the fire suppression system verification tests conducted on the CIR in March 2003. Once these numerical simulations are validated, portions of the ISS labs and living areas will be modeled to determine the local flow conditions before, during, and after a fire event. These simulations can yield specific information about how long it takes for smoke and
International Nuclear Information System (INIS)
Bauge, E.; Bersillon, O.
2000-01-01
This paper presents the transparencies of the speech concerning the nuclear models, experiments and data libraries needed for numerical simulation of Accelerator-Driven Systems. The first part concerning the nuclear models defines the spallation process, the corresponding models (intra-nuclear cascade, statistical model, Fermi breakup, fission, transport, decay and macroscopic aspects) and the code systems. The second part devoted to the experiments presents the angular measurements, the integral measurements, the residual nuclei and the energy deposition. In the last part, dealing with the data libraries, the author details the fundamental quantities as the reaction cross-section, the low energy transport databases and the decay libraries. (A.L.B.)
Numerical evaluation of integrals containing a spherical Bessel function by product integration
International Nuclear Information System (INIS)
Lehman, D.R.; Parke, W.C.; Maximon, L.C.
1981-01-01
A method is developed for numerical evaluation of integrals with k-integration range from 0 to infinity that contain a spherical Bessel function j/sub l/(kr) explicitly. The required quadrature weights are easily calculated and the rate of convergence is rapid: only a relatively small number of quadrature points is needed: for an accurate evaluation even when r is large. The quadrature rule is obtained by the method of product integration. With the abscissas chosen to be those of Clenshaw--Curtis and the Chebyshev polynomials as the interpolating polynomials, quadrature weights are obtained that depend on the spherical Bessel function. An inhomogenous recurrence relation is derived from which the weights can be calculated without accumulation of roundoff error. The procedure is summarized as an easily implementable algorithm. Questions of convergence are discussed and the rate of convergence demonstrated for several test integrals. Alternative procedures are given for generating the integration weights and an error analysis of the method is presented
Self-adaptive numerical integrator for analytic functions
International Nuclear Information System (INIS)
Garribba, S.; Quartapelle, L.; Reina, G.
1978-01-01
A new adaptive algorithm for the integration of analytical functions is presented. The algorithm processes the integration interval by generating local subintervals whose length is controlled through a feedback loop. The control is obtained by means of a relation derived on an analytical basis and valid for an arbitrary integration rule: two different estimates of an integral are used to compute the interval length necessary to obtain an integral estimate with accuracy within the assigned error bounds. The implied method for local generation of subintervals and an effective assumption of error partition among subintervals give rise to an adaptive algorithm provided with a highly accurate and very efficient integration procedure. The particular algorithm obtained by choosing the 6-point Gauss-Legendre integration rule is considered and extensive comparisons are made with other outstanding integration algorithms
Interpretation of ponded infiltration data using numerical experiments
Directory of Open Access Journals (Sweden)
Dohnal Michal
2016-09-01
Full Text Available Ponded infiltration experiment is a simple test used for in-situ determination of soil hydraulic properties, particularly saturated hydraulic conductivity and sorptivity. It is known that infiltration process in natural soils is strongly affected by presence of macropores, soil layering, initial and experimental conditions etc. As a result, infiltration record encompasses a complex of mutually compensating effects that are difficult to separate from each other. Determination of sorptivity and saturated hydraulic conductivity from such infiltration data is complicated. In the present study we use numerical simulation to examine the impact of selected experimental conditions and soil profile properties on the ponded infiltration experiment results, specifically in terms of the hydraulic conductivity and sorptivity evaluation. The effect of following factors was considered: depth of ponding, ring insertion depth, initial soil water content, presence of preferential pathways, hydraulic conductivity anisotropy, soil layering, surface layer retention capacity and hydraulic conductivity, and presence of soil pipes or stones under the infiltration ring. Results were compared with a large database of infiltration curves measured at the experimental site Liz (Bohemian Forest, Czech Republic. Reasonably good agreement between simulated and observed infiltration curves was achieved by combining several of factors tested. Moreover, the ring insertion effect was recognized as one of the major causes of uncertainty in the determination of soil hydraulic parameters.
Numerical Experiments Based on the Catastrophe Model of Solar Eruptions
Xie, X. Y.; Ziegler, U.; Mei, Z. X.; Wu, N.; Lin, J.
2017-11-01
On the basis of the catastrophe model developed by Isenberg et al., we use the NIRVANA code to perform the magnetohydrodynamics (MHD) numerical experiments to look into various behaviors of the coronal magnetic configuration that includes a current-carrying flux rope used to model the prominence levitating in the corona. These behaviors include the evolution in equilibrium heights of the flux rope versus the change in the background magnetic field, the corresponding internal equilibrium of the flux rope, dynamic properties of the flux rope after the system loses equilibrium, as well as the impact of the referential radius on the equilibrium heights of the flux rope. In our calculations, an empirical model of the coronal density distribution given by Sittler & Guhathakurta is used, and the physical diffusion is included. Our experiments show that the deviation of simulations in the equilibrium heights from the theoretical results exists, but is not apparent, and the evolutionary features of the two results are similar. If the flux rope is initially locate at the stable branch of the theoretical equilibrium curve, the flux rope will quickly reach the equilibrium position in the simulation after several rounds of oscillations as a result of the self-adjustment of the system; and the flux rope lose the equilibrium if the initial location of the flux rope is set at the critical point on the theoretical equilibrium curve. Correspondingly, the internal equilibrium of the flux rope can be reached as well, and the deviation from the theoretical results is somewhat apparent since the approximation of the small radius of the flux rope is lifted in our experiments, but such deviation does not affect the global equilibrium in the system. The impact of the referential radius on the equilibrium heights of the flux rope is consistent with the prediction of the theory. Our calculations indicate that the motion of the flux rope after the loss of equilibrium is consistent with which
Optimal stability polynomials for numerical integration of initial value problems
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
Numerical method for solving linear Fredholm fuzzy integral equations of the second kind
Energy Technology Data Exchange (ETDEWEB)
Abbasbandy, S. [Department of Mathematics, Imam Khomeini International University, P.O. Box 288, Ghazvin 34194 (Iran, Islamic Republic of)]. E-mail: saeid@abbasbandy.com; Babolian, E. [Faculty of Mathematical Sciences and Computer Engineering, Teacher Training University, Tehran 15618 (Iran, Islamic Republic of); Alavi, M. [Department of Mathematics, Arak Branch, Islamic Azad University, Arak 38135 (Iran, Islamic Republic of)
2007-01-15
In this paper we use parametric form of fuzzy number and convert a linear fuzzy Fredholm integral equation to two linear system of integral equation of the second kind in crisp case. We can use one of the numerical method such as Nystrom and find the approximation solution of the system and hence obtain an approximation for fuzzy solution of the linear fuzzy Fredholm integral equations of the second kind. The proposed method is illustrated by solving some numerical examples.
International Nuclear Information System (INIS)
Wehner, M.F.
1983-01-01
A path-integral solution is derived for processes described by nonlinear Fokker-Plank equations together with externally imposed boundary conditions. This path-integral solution is written in the form of a path sum for small time steps and contains, in addition to the conventional volume integral, a surface integral which incorporates the boundary conditions. A previously developed numerical method, based on a histogram representation of the probability distribution, is extended to a trapezoidal representation. This improved numerical approach is combined with the present path-integral formalism for restricted processes and is show t give accurate results. 35 refs., 5 figs
Numerical Time Integration Methods for a Point Absorber Wave Energy Converter
DEFF Research Database (Denmark)
Zurkinden, Andrew Stephen; Kramer, Morten
2012-01-01
on a discretization of the convolution integral. The calculation of the convolution integral is performed at each time step regardless of the chosen numerical scheme. In the second model the convolution integral is replaced by a system of linear ordinary differential equations. The formulation of the state...
Numerical Integration of Stiff System of Ordinary Differential ...
African Journals Online (AJOL)
The goal of this work is to develop, analyse and implement a K-step Implicit Rational Runge-Kutta schemes for Integration of Stiff system of Ordinary differential Equations. Its development adopted Taylor and Binomial series expansion Techniques to generate its parameters. The analysis of its basic properties adopted ...
Numerical estimation of structural integrity of salt cavern wells.
Orlic, B.; Thienen-Visser, K. van; Schreppers, G.J.
2016-01-01
Finite element analyses were performed to estimate axial deformation of cavern wells due to gas storage operations in solution-mined salt caverns. Caverns shrink over time due to salt creep and the cavern roof subsides potentially threatening well integrity. Cavern deformation, deformation of salt
Numerical integration of the Teukolsky equation in the time domain
International Nuclear Information System (INIS)
Pazos-Avalos, Enrique; Lousto, Carlos O.
2005-01-01
We present a fourth-order convergent (2+1)-dimensional, numerical formalism to solve the Teukolsky equation in the time domain. Our approach is first to rewrite the Teukolsky equation as a system of first-order differential equations. In this way we get a system that has the form of an advection equation. This is then used in combination with a series expansion of the solution in powers of time. To obtain a fourth-order scheme we kept terms up to fourth derivative in time and use the advectionlike system of differential equations to substitute the temporal derivatives by spatial derivatives. This scheme is applied to evolve gravitational perturbations in the Schwarzschild and Kerr backgrounds. Our numerical method proved to be stable and fourth-order convergent in r* and θ directions. The correct power-law tail, ∼1/t 2l+3 , for general initial data, and ∼1/t 2l+4 , for time-symmetric data, was found in our runs. We noted that it is crucial to resolve accurately the angular dependence of the mode at late times in order to obtain these values of the exponents in the power-law decay. In other cases, when the decay was too fast and round-off error was reached before a tail was developed, then the quasinormal modes frequencies provided a test to determine the validity of our code
Numerical Simulation of Antennas with Improved Integral Equation Method
International Nuclear Information System (INIS)
Ma Ji; Fang Guang-You; Lu Wei
2015-01-01
Simulating antennas around a conducting object is a challenge task in computational electromagnetism, which is concerned with the behaviour of electromagnetic fields. To analyze this model efficiently, an improved integral equation-fast Fourier transform (IE-FFT) algorithm is presented in this paper. The proposed scheme employs two Cartesian grids with different size and location to enclose the antenna and the other object, respectively. On the one hand, IE-FFT technique is used to store matrix in a sparse form and accelerate the matrix-vector multiplication for each sub-domain independently. On the other hand, the mutual interaction between sub-domains is taken as the additional exciting voltage in each matrix equation. By updating integral equations several times, the whole electromagnetic system can achieve a stable status. Finally, the validity of the presented method is verified through the analysis of typical antennas in the presence of a conducting object. (paper)
ORNL fusion reactor shielding integral experiments
International Nuclear Information System (INIS)
Santoro, R.T.; Alsmiller, R.G. Jr.; Barnes, J.M.; Chapman, G.T.
1980-01-01
Integral experiments that measure the neutron and gamma-ray energy spectra resulting from the attenuation of approx. 14 MeV T(D,n) 4 He reaction neutrons in laminated slabs of stainless steel type 304, borated polyethylene, and a tungsten alloy (Hevimet) and from neutrons streaming through a 30-cm-diameter iron duct (L/D = 3) imbedded in a concrete shield have been performed. The facility, the NE-213 liquid scintillator detector system, and the experimental techniques used to obtain the measured data are described. The two-dimensional discrete ordinates radiation transport codes, calculational models, and nuclear data used in the analysis of the experiments are reviewed
Energy Technology Data Exchange (ETDEWEB)
Liu, Fang, E-mail: fliu@lsec.cc.ac.cn [School of Statistics and Mathematics, Central University of Finance and Economics, Beijing 100081 (China); Lin, Lin, E-mail: linlin@math.berkeley.edu [Department of Mathematics, University of California, Berkeley, CA 94720 (United States); Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Vigil-Fowler, Derek, E-mail: vigil@berkeley.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lischner, Johannes, E-mail: jlischner597@gmail.com [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kemper, Alexander F., E-mail: afkemper@lbl.gov [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sharifzadeh, Sahar, E-mail: ssharifz@bu.edu [Department of Electrical and Computer Engineering and Division of Materials Science and Engineering, Boston University, Boston, MA 02215 (United States); Jornada, Felipe H. da, E-mail: jornada@berkeley.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Deslippe, Jack, E-mail: jdeslippe@lbl.gov [NERSC, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Yang, Chao, E-mail: cyang@lbl.gov [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); and others
2015-04-01
We present a numerical integration scheme for evaluating the convolution of a Green's function with a screened Coulomb potential on the real axis in the GW approximation of the self energy. Our scheme takes the zero broadening limit in Green's function first, replaces the numerator of the integrand with a piecewise polynomial approximation, and performs principal value integration on subintervals analytically. We give the error bound of our numerical integration scheme and show by numerical examples that it is more reliable and accurate than the standard quadrature rules such as the composite trapezoidal rule. We also discuss the benefit of using different self energy expressions to perform the numerical convolution at different frequencies.
Advanced Numerical Integration Techniques for HighFidelity SDE Spacecraft Simulation
National Aeronautics and Space Administration — Classic numerical integration techniques, such as the ones at the heart of several NASA GSFC analysis tools, are known to work well for deterministic differential...
International Nuclear Information System (INIS)
Killingbeck, J.
1979-01-01
By using the methods of perturbation theory it is possible to construct simple formulae for the numerical integration of the Schroedinger equation, and also to calculate expectation values solely by means of simple eigenvalue calculations. (Auth.)
DESIGN ANALYSIS OF ELECTRICAL MACHINES THROUGH INTEGRATED NUMERICAL APPROACH
Directory of Open Access Journals (Sweden)
ARAVIND C.V.
2016-02-01
Full Text Available An integrated design platform for the newer type of machines is presented in this work. The machine parameters are evaluated out using developed modelling tool. With the machine parameters, the machine is modelled using computer aided tool. The designed machine is brought to simulation tool to perform electromagnetic and electromechanical analysis. In the simulation, conditions setting are performed to setup the materials, meshes, rotational speed and the excitation circuit. Electromagnetic analysis is carried out to predict the behavior of the machine based on the movement of flux in the machines. Besides, electromechanical analysis is carried out to analyse the speed-torque characteristic, the current-torque characteristic and the phase angle-torque characteristic. After all the results are analysed, the designed machine is used to generate S block function that is compatible with MATLAB/SIMULINK tool for the dynamic operational characteristics. This allows the integration of existing drive system into the new machines designed in the modelling tool. An example of the machine design is presented to validate the usage of such a tool.
Nucleation and solidification of thin walled ductile iron - Experiments and numerical simulation
DEFF Research Database (Denmark)
Pedersen, Karl Martin; Tiedje, Niels Skat
2005-01-01
Investigation of solidification of thin walled ductile cast iron has been performed based on experiments and numerical simulation. The experiments were based on temperature and microstructure examination. Results of the experiments have been compared with a 1-D numerical solidification model...
Numerical Integration of the Vlasov Equation of Two Colliding Beams
Zorzano-Mier, M P
2000-01-01
In a circular collider the motion of particles of one beam is strongly perturbed at the interaction points by the electro-magnetic field associated with the counter-rotating beam. For any two arbitrary initial particle distributions the time evolution of the two beams can be known by solving the coupled system of two Vlasov equations. This collective description is mandatory when the two beams have similar strengths, as in the case of LEP or LHC. The coherent modes excited by this beam-beam interaction can be a strong limitation for the operation of LHC. In this work, the coupled Vlasov equations of two colliding flat beams are solved numerically using a finite difference scheme. The results suggest that, for the collision of beams with equal tunes, the tune shift between the $\\sigma$- and $\\pi$- coherent dipole mode depends on the unperturbed tune $q$ because of the deformation that the so-called dynamic beta effect induces on the beam distribution. Only when the unperturbed tune $q\\rightarrow 0.25$ this tun...
Numerical method for solving integral equations of neutron transport. II
International Nuclear Information System (INIS)
Loyalka, S.K.; Tsai, R.W.
1975-01-01
In a recent paper it was pointed out that the weakly singular integral equations of neutron transport can be quite conveniently solved by a method based on subtraction of singularity. This previous paper was devoted entirely to the consideration of simple one-dimensional isotropic-scattering and one-group problems. The present paper constitutes interesting extensions of the previous work in that in addition to a typical two-group anisotropic-scattering albedo problem in the slab geometry, the method is also applied to an isotropic-scattering problem in the x-y geometry. These results are compared with discrete S/sub N/ (ANISN or TWOTRAN-II) results, and for the problems considered here, the proposed method is found to be quite effective. Thus, the method appears to hold considerable potential for future applications. (auth)
An Integrated Numerical Model of the Spray Forming Process
DEFF Research Database (Denmark)
Pryds, Nini; Hattel, Jesper; Pedersen, Trine Bjerre
2002-01-01
of the deposition model is accomplished using a 2D cylindrical heat flow model. This model is now coupled with an atomization model via a log-normal droplet size distribution. The coupling between the atomization and the deposition is accomplished by ensuring that the total droplet size distribution of the spray......In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation...... is in fact the summation of 'local' droplet size distributions along the r-axis. A key parameter, which determines the yield and the shape of the deposit material, is the sticking efficiency. The sticking phenomenon is therefore incorporated into the deposition model. (C) 2002 Acta Materialia Inc. Published...
High-precision numerical integration of equations in dynamics
Alesova, I. M.; Babadzanjanz, L. K.; Pototskaya, I. Yu.; Pupysheva, Yu. Yu.; Saakyan, A. T.
2018-05-01
An important requirement for the process of solving differential equations in Dynamics, such as the equations of the motion of celestial bodies and, in particular, the motion of cosmic robotic systems is high accuracy at large time intervals. One of effective tools for obtaining such solutions is the Taylor series method. In this connection, we note that it is very advantageous to reduce the given equations of Dynamics to systems with polynomial (in unknowns) right-hand sides. This allows us to obtain effective algorithms for finding the Taylor coefficients, a priori error estimates at each step of integration, and an optimal choice of the order of the approximation used. In the paper, these questions are discussed and appropriate algorithms are considered.
Optimal stability polynomials for numerical integration of initial value problems
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.
Numerical experiment with modelled return echo of a satellite
Indian Academy of Sciences (India)
Abstract. We have simulated the return echo of a satellite altimeter from a rough ocean surface using an analytical formula and have studied its sensitivity with respect to various oceanic and altimeter parameters. Our numerical expcriment shows that for normally observed significant wave heights (SWFI) the effect of ...
Planning for an Integrated Research Experiment
International Nuclear Information System (INIS)
Barnard, J.J.; Ahle, L.E.; Bangerter, R.O.; Bieniosek, F.M.; Celata, C.M.; Faltens, A.; Friedman, A.; Grote, D.P.; Haber, I.; Henestroza, E.; Kishek, R.A.; Hoon, M.J.L. de; Karpenko, V.P.; Kwan, J.W.; Lee, E.P.; Logan, B.G.; Lund, S.M.; Meier, W.R.; Molvik, A.W.; Sangster, T.C.; Seidl, P.A.; Sharp, W.M.
2000-01-01
The authors describe the goals and research program leading to the Heavy Ion Integrated Research Experiment (IRE). They review the basic constraints which lead to a design and give examples of parameters and capabilities of an IRE. We also show design tradeoffs generated by the systems code IBEAM. A multi-pronged Phase 1 research effort is laying the groundwork for the Integrated Research Experiment. Experiment, technology development, theory, simulation, and systems studies are all playing major roles in this Phase I research. The key research areas are: (1) Source and injector (for investigation of a high brightness, multiple beam, low cost injector); (2) High current transport (to examine effects at full driver-scale line charge density, including the maximization of the beam filling-factor and control of electrons); (3) Enabling technology development (low cost and high performance magnetic core material, superconducting magnetic quadrupole arrays, insulators, and pulsers); and (4) Beam simulations and theory (for investigations of beam matching, specification of accelerator errors, studies of emittance growth, halo, and bunch compression, in the accelerator, and neutralization methods, stripping effects, spot size minimization in the chamber); and (5) Systems optimization (minimization of cost and maximization of pulse energy and beam intensity). They have begun the process of designing, simulating, and optimizing the next major heavy-ion induction accelerator, the IRE. This accelerator facility will, in turn, help provide the basis to proceed to the next step in the development of IFE as an attractive source of fusion energy
Numerical Treatment of Fixed Point Applied to the Nonlinear Fredholm Integral Equation
Directory of Open Access Journals (Sweden)
Berenguer MI
2009-01-01
Full Text Available The authors present a method of numerical approximation of the fixed point of an operator, specifically the integral one associated with a nonlinear Fredholm integral equation, that uses strongly the properties of a classical Schauder basis in the Banach space .
Simulation of integrated beam experiment designs
International Nuclear Information System (INIS)
Grote, D.P.; Sharp, W.M.
2004-01-01
Simulation of designs of an Integrated Beam Experiment (IBX) class accelerator have been carried out. These simulations are an important tool for validating such designs. Issues such as envelope mismatch and emittance growth can be examined in a self-consistent manner, including the details of injection, accelerator transitions, long-term transport, and longitudinal compression. The simulations are three-dimensional and time-dependent, and begin at the source. They continue up through the end of the acceleration region, at which point the data is passed on to a separate simulation of the drift compression. Results are be presented
Taylor bubbles at high viscosity ratios: experiments and numerical simulations
Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar
2015-11-01
The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.
Fusion Ignition Research Experiment System Integration
International Nuclear Information System (INIS)
Brown, T.
1999-01-01
The FIRE (Fusion Ignition Research Experiment) configuration has been designed to meet the physics objectives and subsystem requirements in an arrangement that allows remote maintenance of in-vessel components and hands-on maintenance of components outside the TF (toroidal-field) boundary. The general arrangement consists of sixteen wedged-shaped TF coils that surround a free-standing central solenoid (CS), a double-wall vacuum vessel and internal plasma-facing components. A center tie rod is used to help support the vertical magnetic loads and a compression ring is used to maintain wedge pressure in the inboard corners of the TF coils. The magnets are liquid nitrogen cooled and the entire device is surrounded by a thermal enclosure. The double-wall vacuum vessel integrates cooling and shielding in a shape that maximizes shielding of ex-vessel components. The FIRE configuration development and integration process has evolved from an early stage of concept selection to a higher level of machine definition and component details. This paper describes the status of the configuration development and the integration of the major subsystem components
International Nuclear Information System (INIS)
Chernyshenko, Dmitri; Fangohr, Hans
2015-01-01
In the finite difference method which is commonly used in computational micromagnetics, the demagnetizing field is usually computed as a convolution of the magnetization vector field with the demagnetizing tensor that describes the magnetostatic field of a cuboidal cell with constant magnetization. An analytical expression for the demagnetizing tensor is available, however at distances far from the cuboidal cell, the numerical evaluation of the analytical expression can be very inaccurate. Due to this large-distance inaccuracy numerical packages such as OOMMF compute the demagnetizing tensor using the explicit formula at distances close to the originating cell, but at distances far from the originating cell a formula based on an asymptotic expansion has to be used. In this work, we describe a method to calculate the demagnetizing field by numerical evaluation of the multidimensional integral in the demagnetizing tensor terms using a sparse grid integration scheme. This method improves the accuracy of computation at intermediate distances from the origin. We compute and report the accuracy of (i) the numerical evaluation of the exact tensor expression which is best for short distances, (ii) the asymptotic expansion best suited for large distances, and (iii) the new method based on numerical integration, which is superior to methods (i) and (ii) for intermediate distances. For all three methods, we show the measurements of accuracy and execution time as a function of distance, for calculations using single precision (4-byte) and double precision (8-byte) floating point arithmetic. We make recommendations for the choice of scheme order and integrating coefficients for the numerical integration method (iii). - Highlights: • We study the accuracy of demagnetization in finite difference micromagnetics. • We introduce a new sparse integration method to compute the tensor more accurately. • Newell, sparse integration and asymptotic method are compared for all ranges
Inverse problem of Ocean Acoustic Tomography (OAT) - A numerical experiment
Digital Repository Service at National Institute of Oceanography (India)
Murty, T.V.R.; Somayajulu, Y.K.; Mahadevan, R.; Murty, C.S.
Acoustic model simulation experiments related to the forward and inverse aspects of ocean tomography have been taken up with a view to estimate the vertical sound speed field by inverting the travel time data. Two methods of inversion have been...
An accurate real-time model of maglev planar motor based on compound Simpson numerical integration
Directory of Open Access Journals (Sweden)
Baoquan Kou
2017-05-01
Full Text Available To realize the high-speed and precise control of the maglev planar motor, a more accurate real-time electromagnetic model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic model. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed model has high accuracy and can realize practical application easily.
An accurate real-time model of maglev planar motor based on compound Simpson numerical integration
Kou, Baoquan; Xing, Feng; Zhang, Lu; Zhou, Yiheng; Liu, Jiaqi
2017-05-01
To realize the high-speed and precise control of the maglev planar motor, a more accurate real-time electromagnetic model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic model. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed model has high accuracy and can realize practical application easily.
Analysis of thermal-plastic response of shells of revolution by numerical integration
International Nuclear Information System (INIS)
Leonard, J.W.
1975-01-01
An economic technique for the numerical analysis of the elasto-plastic behaviour of shells of revolution would be of considerable value in the nuclear reactor industry. A numerical method based on the numerical integration of the governing shell equations has been shown, for elastic cases, to be more efficient than the finite element method when applied to shells of revolution. In the numerical integration method, the governing differential equations of motion are converted into a set of initial-value problems. Each initial-value problem is integrated numerically between meridional boundary points and recombined so as to satisfy boundary conditions. For large-deflection elasto-plastic behaviour, the equations are nonlinear and, hence, are recombined in an iterative manner using the Newton-Raphson procedure. Suppression techniques are incorporated in order to eliminate extraneous solutions within the numerical integration procedure. The Reissner-Meissner shell theory for shells of revolution is adopted to account for large deflection and higher-order rotation effects. The computer modelling of the equations is quite general in that specific shell segment geometries, e.g. cylindrical, spherical, toroidal, conical segments, and any combinations thereof can be handled easily. (Auth.)
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.
Multi-symplectic integrators: numerical schemes for Hamiltonian PDEs that conserve symplecticity
Bridges, Thomas J.; Reich, Sebastian
2001-06-01
The symplectic numerical integration of finite-dimensional Hamiltonian systems is a well established subject and has led to a deeper understanding of existing methods as well as to the development of new very efficient and accurate schemes, e.g., for rigid body, constrained, and molecular dynamics. The numerical integration of infinite-dimensional Hamiltonian systems or Hamiltonian PDEs is much less explored. In this Letter, we suggest a new theoretical framework for generalizing symplectic numerical integrators for ODEs to Hamiltonian PDEs in R2: time plus one space dimension. The central idea is that symplecticity for Hamiltonian PDEs is directional: the symplectic structure of the PDE is decomposed into distinct components representing space and time independently. In this setting PDE integrators can be constructed by concatenating uni-directional ODE symplectic integrators. This suggests a natural definition of multi-symplectic integrator as a discretization that conserves a discrete version of the conservation of symplecticity for Hamiltonian PDEs. We show that this approach leads to a general framework for geometric numerical schemes for Hamiltonian PDEs, which have remarkable energy and momentum conservation properties. Generalizations, including development of higher-order methods, application to the Euler equations in fluid mechanics, application to perturbed systems, and extension to more than one space dimension are also discussed.
Interpretation of ponded infiltration data using numerical experiments
Czech Academy of Sciences Publication Activity Database
Dohnal, M.; Vogel, T.; Dušek, J.; Votrubová, J.; Tesař, Miroslav
2016-01-01
Roč. 64, č. 3 (2016), s. 289-299 ISSN 0042-790X Institutional support: RVO:67985874 Keywords : ponded infiltration experiment * two-parameter infiltration equation * three-dimensional axisymmetric dualcontinuum model * preferential flow Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.654, year: 2016
Numerical experiments on 2D strongly coupled complex plasmas
International Nuclear Information System (INIS)
Hou Lujing; Ivlev, A V; Thomas, H M; Morfill, G E
2010-01-01
The Brownian Dynamics simulation method is briefly reviewed at first and then applied to study some non-equilibrium phenomena in strongly coupled complex plasmas, such as heat transfer processes, shock wave excitation/propagation and particle trapping, by directly mimicking the real experiments.
Numerical simulation and experiment on multilayer stagger-split die.
Liu, Zhiwei; Li, Mingzhe; Han, Qigang; Yang, Yunfei; Wang, Bolong; Sui, Zhou
2013-05-01
A novel ultra-high pressure device, multilayer stagger-split die, has been constructed based on the principle of "dividing dies before cracking." Multilayer stagger-split die includes an encircling ring and multilayer assemblages, and the mating surfaces of the multilayer assemblages are mutually staggered between adjacent layers. In this paper, we investigated the stressing features of this structure through finite element techniques, and the results were compared with those of the belt type die and single split die. The contrast experiments were also carried out to test the bearing pressure performance of multilayer stagger-split die. It is concluded that the stress distributions are reasonable and the materials are utilized effectively for multilayer stagger-split die. And experiments indicate that the multilayer stagger-split die can bear the greatest pressure.
Computational techniques for inelastic analysis and numerical experiments
International Nuclear Information System (INIS)
Yamada, Y.
1977-01-01
A number of formulations have been proposed for inelastic analysis, particularly for the thermal elastic-plastic creep analysis of nuclear reactor components. In the elastic-plastic regime, which principally concerns with the time independent behavior, the numerical techniques based on the finite element method have been well exploited and computations have become a routine work. With respect to the problems in which the time dependent behavior is significant, it is desirable to incorporate a procedure which is workable on the mechanical model formulation as well as the method of equation of state proposed so far. A computer program should also take into account the strain-dependent and/or time-dependent micro-structural changes which often occur during the operation of structural components at the increasingly high temperature for a long period of time. Special considerations are crucial if the analysis is to be extended to large strain regime where geometric nonlinearities predominate. The present paper introduces a rational updated formulation and a computer program under development by taking into account the various requisites stated above. (Auth.)
Wang, Yi
2016-07-21
Velocity of fluid flow in underground porous media is 6~12 orders of magnitudes lower than that in pipelines. If numerical errors are not carefully controlled in this kind of simulations, high distortion of the final results may occur [1-4]. To fit the high accuracy demands of fluid flow simulations in porous media, traditional finite difference methods and numerical integration methods are discussed and corresponding high-accurate methods are developed. When applied to the direct calculation of full-tensor permeability for underground flow, the high-accurate finite difference method is confirmed to have numerical error as low as 10-5% while the high-accurate numerical integration method has numerical error around 0%. Thus, the approach combining the high-accurate finite difference and numerical integration methods is a reliable way to efficiently determine the characteristics of general full-tensor permeability such as maximum and minimum permeability components, principal direction and anisotropic ratio. Copyright © Global-Science Press 2016.
Analysis of thermal-plastic response of shells of revolution by numerical integration
International Nuclear Information System (INIS)
Leonard, J.W.
1975-01-01
A numerical method based instead on the numerical integration of the governing shell equations has been shown, for elastic cases, to be more efficient than the finite element method when applied to shells of revolution. In the numerical integration method, the governing differential equations of motions are converted into a set of initial-value problems. Each initial-value problem is integrated numerically between meridional boundary points and recombined so as to satisfy boundary conditions. For large-deflection elasto-plastic behavior, the equations are nonlinear and, hence, are recombined in an iterative manner using the Newton-Raphson procedure. Suppression techniques are incorporated in order to eliminate extraneous solutions within the numerical integration procedure. The Reissner-Meissner shell theory for shells of revolution is adopted to account for large deflection and higher-order rotation effects. The computer modelling of the equations is quite general in that specific shell segment geometries, e.g. cylindrical, spherical, toroidal, conical segments, and any combinations thereof can be handled easily. The elasto-plastic constitutive relations adopted are in accordance with currently recommended constitutive equations for inelastic design analysis of FFTF Components. The Von Mises yield criteria and associated flow rule is used and the kinematic hardening law is followed. Examples are considered in which stainless steels common to LMFBR application are used
Experimental research and numerical simulation on flow resistance of integrated valve
International Nuclear Information System (INIS)
Cai Wei; Bo Hanliang; Qin Benke
2008-01-01
The flow resistance of the integrated valve is one of the key parameters for the design of the control rod hydraulic drive system (CRHDS). Experimental research on the improved new integrated valve was performed, and the key data such as pressure difference, volume flow, resistance coefficient and flow coefficient of each flow channel were obtained. With the computational fluid dynamics software CFX, numerical simulation was executed to analyze the effect of Re on the flow resistance. On the basis of experimental and numerical results, fitting empirical formulas of resistance coefficient were obtained, which provide experimental and theoretical foundations for CRHDS's optimized design and theoretical analysis. (authors)
pySecDec: A toolbox for the numerical evaluation of multi-scale integrals
Borowka, S.; Heinrich, G.; Jahn, S.; Jones, S. P.; Kerner, M.; Schlenk, J.; Zirke, T.
2018-01-01
We present pySECDEC, a new version of the program SECDEC, which performs the factorization of dimensionally regulated poles in parametric integrals, and the subsequent numerical evaluation of the finite coefficients. The algebraic part of the program is now written in the form of python modules, which allow a very flexible usage. The optimization of the C++ code, generated using FORM, is improved, leading to a faster numerical convergence. The new version also creates a library of the integrand functions, such that it can be linked to user-specific codes for the evaluation of matrix elements in a way similar to analytic integral libraries.
Integrated safeguards: Australian views and experience
International Nuclear Information System (INIS)
Carlson, J.; Bragin, V.; Leslie, R.
2001-01-01
Full text: Australia has had a pioneering role in assisting the IAEA to develop the procedures and methods for strengthened safeguards, both before and after the conclusion of Australia's additional protocol. Australia played a key role in the negotiation of the model additional protocol, and made ratification a high priority in order to encourage early ratification by other States. Australia was the first State to ratify an additional protocol, on 10 December 1997, and was the first State in which the IAEA exercised complementary access and managed access under an additional protocol. Australia has undergone three full cycles of evaluation under strengthened safeguards measures, enabling the Agency to conclude it was appropriate to commence implementation of integrated safeguards. In January 2001 Australia became the first State in which integrated safeguards are being applied. As such, Australia's experience will be of interest to other States as they consult with the IAEA on the modalities for the introduction of integrated safeguards in their jurisdictions. The purpose of the paper is to outline Australia's experience with strengthened safeguards and Australia's views on the implementation of integrated safeguards. Australia has five Material Balance Areas (MBAs), the principal one covering the 10 MWt research reactor at Lucas Heights and the associated inventory of fresh and irradiated HEU fuel. Under classical safeguards, generally Australia was subject to annual Physical Inventory Verifications (PIVs) for the four MBAs at Lucas Heights, plus quarterly interim inspections, making a total of four inspections a year (PIVs for the different MBAs were conducted concurrently with each other or with interim inspections in other MBAs), although there was a period when the fresh fuel inventory exceeded one SQ, requiring monthly inspections. Under strengthened safeguards, this pattern of four inspections a year was maintained, with the addition of complementary
Numerical analysis of two experiments related to thermal fatigue
Energy Technology Data Exchange (ETDEWEB)
Bieder, Ulrich; Errante, Paolo [DEN-STMF, Commissariat a l' Energie Atomique et aux Energies Alternatives, Universite Paris-Saclay, Gif-sur-Yvette (France)
2017-06-15
Jets in cross flow are of fundamental industrial importance and play an important role in validating turbulence models. Two jet configurations related to thermal fatigue phenomena are investigated: • T-junction of circular tubes where a heated jet discharges into a cold main flow and • Rectangular jet marked by a scalar discharging into a main flow in a rectangular channel. The T-junction configuration is a classical test case for thermal fatigue phenomena. The Vattenfall T-junction experiment was already subject of an OECD/NEA benchmark. A LES modelling and calculation strategy is developed and validated on this data. The rectangular-jet configuration is important for basic physical understanding and modelling and has been analyzed experimentally at CEA. The experimental work was focused on turbulent mixing between a slightly heated rectangular jet which is injected perpendicularly into the cold main flow of a rectangular channel. These experiments are analyzed for the first time with LES. The overall results show a good agreement between the experimental data and the CFD calculation. Mean values of velocity and temperature are well captured by both RANS calculation and LES. The range of critical frequencies and their amplitudes, however, are only captured by LES.
Experiments and Numerical Simulations of Dike Erosion due to a Wave Impact
Directory of Open Access Journals (Sweden)
Stefania Evangelista
2015-10-01
Full Text Available Dike erosion is a crucial issue in coastal and fluvial flood risk management. These defense structures appear vulnerable to extreme hydrological events, whose potential occurrence risk seems to be recently increased due to climate change. Their design and reinforcement is, however, a complex task, and although numerical models are very powerful nowadays, real processes cannot be accurately predicted; therefore, physical models constitute a useful tool to investigate different features under controlled conditions. This paper presents some laboratory experimental results of erosion of a sand dike produced by the impact of a dam break wave. Experiments have been conducted in the Water Engineering Laboratory at the University of Cassino and Southern Lazio, Italy, in a rectangular channel: here, the sudden opening of a gate forming the reservoir generates the wave impacting the dike, made in turn of two different, almost uniform sands. The physical evidence proves that the erosion process is strongly unsteady and significantly different from a gradual overtopping and highlights the importance of apparent cohesion for the fine sand dike. The experimental results have also been compared against the ones obtained through the numerical integration of a two-phase model, which shows the reasonable predictive capability of the temporal free surface and dike profile evolution.
Note on the numerical calculation of the Fermi-Dirac integrals
International Nuclear Information System (INIS)
Graef, H.; Pabst, M.
1977-11-01
Expansions of the Fermi-Dirac integrals Fsub(α)(x) are developed, suitable for numerical computation. Only integrals of integer- or half-integer order are treated and expansion coefficients are tabulated for F 1 (x),....,F 9 (x); Fsub(-1/2)(x),...,Fsub(7/2)(x). Maximal relative errors vary with the function and interval considered, but are less than 3 x 10 -6 . (orig.) [de
Numerical modeling of the plasma ring acceleration experiment
International Nuclear Information System (INIS)
Eddleman, J.L.; Hammer, J.H.; Hartman, C.W.
1987-01-01
Modeling of the LLNL RACE experiment and its many applications has necessitated the development and use of a wide array of computational tools. The two-dimensional MHD code, HAM, has been used to model the formation of a compact torus plasma ring in a magnetized coaxial gun and its subsequent acceleration by an additional applied toroidal field. Features included in the 2-D calculations are self-consistent models for (1) the time-dependent poloidal field produced by a capacitor bank discharge through a solenoid field coil (located either inside the gun inner electrode or outside the outer gun electrode) and the associated diffusion of magnetic flux through neighboring conductors, (2) gas flow into the gun annular region from a simulated puffed gas valve plenum, (3) formation and motion of a current sheet produced by J x B forces resulting from discharge of the gun capacitor bank through the plasma load between the coaxial gun electrodes, (4) the subsequent stretching and reconnection of the poloidal field lines to form a compact torus plasma ring, and (5) finally the discharge of the accelerator capacitor bank producing an additional toroidal field for acceleration of the plasma ring. The code has been extended to include various models for gas breakdown, plasma anomalous resistivity, and mass entrainment from ablation of electrode material
A purely Lagrangian method for the numerical integration of Fokker-Planck equations
International Nuclear Information System (INIS)
Combis, P.; Fronteau, J.
1986-01-01
A new numerical approach to Fokker-Planck equations is presented, in which the integration grid moves according to the solution of a differential system. The method is purely Lagrangian, the mean effect of the diffusion being inserted into the differential system itself
DEFF Research Database (Denmark)
Schmidt, Jacob Wittrup; Smith, Scott T.; Täljsten, Björn
2011-01-01
. Recently, an integrated sleeve-wedge anchorage has been successfully developed specifically for CFRP rods. This paper in turn presents a numerical simulation of the newly developed anchorage using ABAQUS. The three-dimensional finite element (FE) model, which considers material non-linearity, uses...
Exponential Convergence for Numerical Solution of Integral Equations Using Radial Basis Functions
Directory of Open Access Journals (Sweden)
Zakieh Avazzadeh
2014-01-01
Full Text Available We solve some different type of Urysohn integral equations by using the radial basis functions. These types include the linear and nonlinear Fredholm, Volterra, and mixed Volterra-Fredholm integral equations. Our main aim is to investigate the rate of convergence to solve these equations using the radial basis functions which have normic structure that utilize approximation in higher dimensions. Of course, the use of this method often leads to ill-posed systems. Thus we propose an algorithm to improve the results. Numerical results show that this method leads to the exponential convergence for solving integral equations as it was already confirmed for partial and ordinary differential equations.
An integrated algorithm for hypersonic fluid-thermal-structural numerical simulation
Li, Jia-Wei; Wang, Jiang-Feng
2018-05-01
In this paper, a fluid-structural-thermal integrated method is presented based on finite volume method. A unified integral equations system is developed as the control equations for physical process of aero-heating and structural heat transfer. The whole physical field is discretized by using an up-wind finite volume method. To demonstrate its capability, the numerical simulation of Mach 6.47 flow over stainless steel cylinder shows a good agreement with measured values, and this method dynamically simulates the objective physical processes. Thus, the integrated algorithm proves to be efficient and reliable.
An integral equation-based numerical solver for Taylor states in toroidal geometries
O'Neil, Michael; Cerfon, Antoine J.
2018-04-01
We present an algorithm for the numerical calculation of Taylor states in toroidal and toroidal-shell geometries using an analytical framework developed for the solution to the time-harmonic Maxwell equations. Taylor states are a special case of what are known as Beltrami fields, or linear force-free fields. The scheme of this work relies on the generalized Debye source representation of Maxwell fields and an integral representation of Beltrami fields which immediately yields a well-conditioned second-kind integral equation. This integral equation has a unique solution whenever the Beltrami parameter λ is not a member of a discrete, countable set of resonances which physically correspond to spontaneous symmetry breaking. Several numerical examples relevant to magnetohydrodynamic equilibria calculations are provided. Lastly, our approach easily generalizes to arbitrary geometries, both bounded and unbounded, and of varying genus.
Directory of Open Access Journals (Sweden)
Suresh Thenozhi
2012-01-01
Full Text Available An important objective of health monitoring systems for tall buildings is to diagnose the state of the building and to evaluate its possible damage. In this paper, we use our prototype to evaluate our data-mining approach for the fault monitoring. The offset cancellation and high-pass filtering techniques are combined effectively to solve common problems in numerical integration of acceleration signals in real-time applications. The integration accuracy is improved compared with other numerical integrators. Then we introduce a novel method for support vector machine (SVM classification, called convex-concave hull. We use the Jarvis march method to decide the concave (nonconvex hull for the inseparable points. Finally the vertices of the convex-concave hull are applied for SVM training.
Integrating conceptualizations of experience into the interaction design process
DEFF Research Database (Denmark)
Dalsgaard, Peter
2010-01-01
From a design perspective, the increasing awareness of experiential aspects of interactive systems prompts the question of how conceptualizations of experience can inform and potentially be integrated into the interaction design process. This paper presents one approach to integrating theoretical...
The Vehicle Integrated Performance Analysis Experience: Reconnecting With Technical Integration
McGhee, D. S.
2006-01-01
Very early in the Space Launch Initiative program, a small team of engineers at MSFC proposed a process for performing system-level assessments of a launch vehicle. Aimed primarily at providing insight and making NASA a smart buyer, the Vehicle Integrated Performance Analysis (VIPA) team was created. The difference between the VIPA effort and previous integration attempts is that VIPA a process using experienced people from various disciplines, which focuses them on a technically integrated assessment. The foundations of VIPA s process are described. The VIPA team also recognized the need to target early detailed analysis toward identifying significant systems issues. This process is driven by the T-model for technical integration. VIPA s approach to performing system-level technical integration is discussed in detail. The VIPA process significantly enhances the development and monitoring of realizable project requirements. VIPA s assessment validates the concept s stated performance, identifies significant issues either with the concept or the requirements, and then reintegrates these issues to determine impacts. This process is discussed along with a description of how it may be integrated into a program s insight and review process. The VIPA process has gained favor with both engineering and project organizations for being responsive and insightful
A numerical integration-based yield estimation method for integrated circuits
International Nuclear Information System (INIS)
Liang Tao; Jia Xinzhang
2011-01-01
A novel integration-based yield estimation method is developed for yield optimization of integrated circuits. This method tries to integrate the joint probability density function on the acceptability region directly. To achieve this goal, the simulated performance data of unknown distribution should be converted to follow a multivariate normal distribution by using Box-Cox transformation (BCT). In order to reduce the estimation variances of the model parameters of the density function, orthogonal array-based modified Latin hypercube sampling (OA-MLHS) is presented to generate samples in the disturbance space during simulations. The principle of variance reduction of model parameters estimation through OA-MLHS together with BCT is also discussed. Two yield estimation examples, a fourth-order OTA-C filter and a three-dimensional (3D) quadratic function are used for comparison of our method with Monte Carlo based methods including Latin hypercube sampling and importance sampling under several combinations of sample sizes and yield values. Extensive simulations show that our method is superior to other methods with respect to accuracy and efficiency under all of the given cases. Therefore, our method is more suitable for parametric yield optimization. (semiconductor integrated circuits)
A numerical integration-based yield estimation method for integrated circuits
Energy Technology Data Exchange (ETDEWEB)
Liang Tao; Jia Xinzhang, E-mail: tliang@yahoo.cn [Key Laboratory of Ministry of Education for Wide Bandgap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)
2011-04-15
A novel integration-based yield estimation method is developed for yield optimization of integrated circuits. This method tries to integrate the joint probability density function on the acceptability region directly. To achieve this goal, the simulated performance data of unknown distribution should be converted to follow a multivariate normal distribution by using Box-Cox transformation (BCT). In order to reduce the estimation variances of the model parameters of the density function, orthogonal array-based modified Latin hypercube sampling (OA-MLHS) is presented to generate samples in the disturbance space during simulations. The principle of variance reduction of model parameters estimation through OA-MLHS together with BCT is also discussed. Two yield estimation examples, a fourth-order OTA-C filter and a three-dimensional (3D) quadratic function are used for comparison of our method with Monte Carlo based methods including Latin hypercube sampling and importance sampling under several combinations of sample sizes and yield values. Extensive simulations show that our method is superior to other methods with respect to accuracy and efficiency under all of the given cases. Therefore, our method is more suitable for parametric yield optimization. (semiconductor integrated circuits)
Rosenbaum, J. S.
1976-01-01
If a system of ordinary differential equations represents a property conserving system that can be expressed linearly (e.g., conservation of mass), it is then desirable that the numerical integration method used conserve the same quantity. It is shown that both linear multistep methods and Runge-Kutta methods are 'conservative' and that Newton-type methods used to solve the implicit equations preserve the inherent conservation of the numerical method. It is further shown that a method used by several authors is not conservative.
Mergers and integrated care: the Quebec experience.
Demers, Louis
2013-01-01
As a researcher, I have studied the efforts to increase the integration of health and social services in Quebec, as well as the mergers in the Quebec healthcare system. These mergers have often been presented as a necessary transition to break down the silos that compartmentalize the services dispensed by various organisations. A review of the studies about mergers and integrated care projects in the Quebec healthcare system, since its inception, show that mergers cannot facilitate integrated care unless they are desired and represent for all of the actors involved an appropriate way to deal with service organisation problems. Otherwise, mergers impede integrated care by creating increased bureaucratisation and standardisation and by triggering conflicts and mistrust among the staff of the merged organisations. It is then preferable to let local actors select the most appropriate organisational integration model for their specific context and offer them resources and incentives to cooperate.
Mergers and integrated care: the Quebec experience
Directory of Open Access Journals (Sweden)
Louis Demers
2013-02-01
Full Text Available As a researcher, I have studied the efforts to increase the integration of health and social services in Quebec, as well as the mergers in the Quebec healthcare system. These mergers have often been presented as a necessary transition to break down the silos that compartmentalize the services dispensed by various organisations. A review of the studies about mergers and integrated care projects in the Quebec healthcare system, since its inception, show that mergers cannot facilitate integrated care unless they are desired and represent for all of the actors involved an appropriate way to deal with service organisation problems. Otherwise, mergers impede integrated care by creating increased bureaucratisation and standardisation and by triggering conflicts and mistrust among the staff of the merged organisations. It is then preferable to let local actors select the most appropriate organisational integration model for their specific context and offer them resources and incentives to cooperate.
Voytishek, Anton V.; Shipilov, Nikolay M.
2017-11-01
In this paper, the systematization of numerical (implemented on a computer) randomized functional algorithms for approximation of a solution of Fredholm integral equation of the second kind is carried out. Wherein, three types of such algorithms are distinguished: the projection, the mesh and the projection-mesh methods. The possibilities for usage of these algorithms for solution of practically important problems is investigated in detail. The disadvantages of the mesh algorithms, related to the necessity of calculation values of the kernels of integral equations in fixed points, are identified. On practice, these kernels have integrated singularities, and calculation of their values is impossible. Thus, for applied problems, related to solving Fredholm integral equation of the second kind, it is expedient to use not mesh, but the projection and the projection-mesh randomized algorithms.
Numerical Study of Two-Dimensional Volterra Integral Equations by RDTM and Comparison with DTM
Directory of Open Access Journals (Sweden)
Reza Abazari
2013-01-01
Full Text Available The two-dimensional Volterra integral equations are solved using more recent semianalytic method, the reduced differential transform method (the so-called RDTM, and compared with the differential transform method (DTM. The concepts of DTM and RDTM are briefly explained, and their application to the two-dimensional Volterra integral equations is studied. The results obtained by DTM and RDTM together are compared with exact solution. As an important result, it is depicted that the RDTM results are more accurate in comparison with those obtained by DTM applied to the same Volterra integral equations. The numerical results reveal that the RDTM is very effective, convenient, and quite accurate compared to the other kind of nonlinear integral equations. It is predicted that the RDTM can be found widely applicable in engineering sciences.
A numerical integration approach suitable for simulating PWR dynamics using a microcomputer system
International Nuclear Information System (INIS)
Zhiwei, L.; Kerlin, T.W.
1983-01-01
It is attractive to use microcomputer systems to simulate nuclear power plant dynamics for the purpose of teaching and/or control system design. An analysis and a comparison of feasibility of existing numerical integration methods have been made. The criteria for choosing the integration step using various numerical integration methods including the matrix exponential method are derived. In order to speed up the simulation, an approach is presented using the Newton recursion calculus which can avoid convergence limitations in choosing the integration step size. The accuracy consideration will dominate the integration step limited. The advantages of this method have been demonstrated through a case study using CBM model 8032 microcomputer to simulate a reduced order linear PWR model under various perturbations. It has been proven theoretically and practically that the Runge-Kutta method and Adams-Moulton method are not feasible. The matrix exponential method is good at accuracy and fairly good at speed. The Newton recursion method can save 3/4 to 4/5 time compared to the matrix exponential method with reasonable accuracy. Vertical Barhis method can be expanded to deal with nonlinear nuclear power plant models and higher order models as well
Numerical evaluation of two-center integrals over Slater type orbitals
Energy Technology Data Exchange (ETDEWEB)
Kurt, S. A., E-mail: slaykurt@gmail.com [Department of Physics, Natural Sciences Institute, Ondokuz Mayıs University, 55139, Samsun (Turkey); Yükçü, N., E-mail: nyukcu@gmail.com [Department of Energy Systems Engineering, Faculty of Technology, Adıyaman University, 02040, Adıyaman (Turkey)
2016-03-25
Slater Type Orbitals (STOs) which one of the types of exponential type orbitals (ETOs) are used usually as basis functions in the multicenter molecular integrals to better understand physical and chemical properties of matter. In this work, we develop algorithms for two-center overlap and two-center two-electron hybrid and Coulomb integrals which are calculated with help of translation method for STOs and some auxiliary functions by V. Magnasco’s group. We use Mathematica programming language to produce algorithms for these calculations. Numerical results for some quantum numbers are presented in the tables. Consequently, we compare our obtained numerical results with the other known literature results and other details of evaluation method are discussed.
Quadrature theory the theory of numerical integration on a compact interval
Brass, Helmut
2011-01-01
Every book on numerical analysis covers methods for the approximate calculation of definite integrals. The authors of this book provide a complementary treatment of the topic by presenting a coherent theory of quadrature methods that encompasses many deep and elegant results as well as a large number of interesting (solved and open) problems. The inclusion of the word "theory" in the title highlights the authors' emphasis on analytical questions, such as the existence and structure of quadrature methods and selection criteria based on strict error bounds for quadrature rules. Systematic analyses of this kind rely on certain properties of the integrand, called "co-observations," which form the central organizing principle for the authors' theory, and distinguish their book from other texts on numerical integration. A wide variety of co-observations are examined, as a detailed understanding of these is useful for solving problems in practical contexts. While quadrature theory is often viewed as a branch of nume...
Numerical evaluation of two-center integrals over Slater type orbitals
International Nuclear Information System (INIS)
Kurt, S. A.; Yükçü, N.
2016-01-01
Slater Type Orbitals (STOs) which one of the types of exponential type orbitals (ETOs) are used usually as basis functions in the multicenter molecular integrals to better understand physical and chemical properties of matter. In this work, we develop algorithms for two-center overlap and two-center two-electron hybrid and Coulomb integrals which are calculated with help of translation method for STOs and some auxiliary functions by V. Magnasco’s group. We use Mathematica programming language to produce algorithms for these calculations. Numerical results for some quantum numbers are presented in the tables. Consequently, we compare our obtained numerical results with the other known literature results and other details of evaluation method are discussed.
Numerical simulation of liquid film flow on revolution surfaces with momentum integral method
International Nuclear Information System (INIS)
Bottoni Maurizio
2005-01-01
The momentum integral method is applied in the frame of safety analysis of pressure water reactors under hypothetical loss of coolant accident (LOCA) conditions to simulate numerically film condensation, rewetting and vaporization on the inner surface of pressure water reactor containment. From the conservation equations of mass and momentum of a liquid film arising from condensation of steam upon the inner of the containment during a LOCA in a pressure water reactor plant, an integro-differential equation is derived, referring to an arbitrary axisymmetric surface of revolution. This equation describes the velocity distribution of the liquid film along a meridian of a surface of revolution. From the integro-differential equation and ordinary differential equation of first order for the film velocity is derived and integrated numerically. From the velocity distribution the film thickness distribution is obtained. The solution of the enthalpy equation for the liquid film yields the temperature distribution on the inner surface of the containment. (authors)
Numerical Algorithms for Acoustic Integrals - The Devil is in the Details
Brentner, Kenneth S.
1996-01-01
The accurate prediction of the aeroacoustic field generated by aerospace vehicles or nonaerospace machinery is necessary for designers to control and reduce source noise. Powerful computational aeroacoustic methods, based on various acoustic analogies (primarily the Lighthill acoustic analogy) and Kirchhoff methods, have been developed for prediction of noise from complicated sources, such as rotating blades. Both methods ultimately predict the noise through a numerical evaluation of an integral formulation. In this paper, we consider three generic acoustic formulations and several numerical algorithms that have been used to compute the solutions to these formulations. Algorithms for retarded-time formulations are the most efficient and robust, but they are difficult to implement for supersonic-source motion. Collapsing-sphere and emission-surface formulations are good alternatives when supersonic-source motion is present, but the numerical implementations of these formulations are more computationally demanding. New algorithms - which utilize solution adaptation to provide a specified error level - are needed.
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
Wolter, Andrea Elaine
2014-01-01
I apply a forensic, multidisciplinary approach that integrates engineering geology field investigations, engineering geomorphology mapping, long-range terrestrial photogrammetry, and a numerical modelling toolbox to two large rock slope failures to study their causes, initiation, kinematics, and dynamics. I demonstrate the significance of endogenic and exogenic processes, both separately and in concert, in contributing to landscape evolution and conditioning slopes for failure, and use geomor...
International Nuclear Information System (INIS)
Adler, A.; Fuchs, B.; Thielheim, K.O.
1977-01-01
The longitudinal development of electromagnetic cascades in air, copper, iron, and lead is studied on the basis of results derived recently by numerical integration of the cascade equations applying rather accurate expressions for the cross-sections involved with the interactions of high energy electrons, positrons, and photons in electromagnetic cascades. Special attention is given to scaling properties of transition curves. It is demonstrated that a good scaling may be achieved by means of the depth of maximum cascade development. (author)
Validation of a numerical FSI simulation of an aortic BMHV by in vitro PIV experiments.
Annerel, S; Claessens, T; Degroote, J; Segers, P; Vierendeels, J
2014-08-01
In this paper, a validation of a recently developed fluid-structure interaction (FSI) coupling algorithm to simulate numerically the dynamics of an aortic bileaflet mechanical heart valve (BMHV) is performed. This validation is done by comparing the numerical simulation results with in vitro experiments. For the in vitro experiments, the leaflet kinematics and flow fields are obtained via the particle image velocimetry (PIV) technique. Subsequently, the same case is numerically simulated by the coupling algorithm and the resulting leaflet kinematics and flow fields are obtained. Finally, the results are compared, revealing great similarity in leaflet motion and flow fields between the numerical simulation and the experimental test. Therefore, it is concluded that the developed algorithm is able to capture very accurately all the major leaflet kinematics and dynamics and can be used to study and optimize the design of BMHVs. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.
U.S. integral and benchmark experiments
International Nuclear Information System (INIS)
Maienschein, F.C.
1978-01-01
Verification of methods for analysis of radiation-transport (shielding) problems in Liquid-Metal Fast Breeder Reactors has required a series of experiments that can be classified as benchmark, parametric, or design-confirmation experiments. These experiments, performed at the Oak Ridge Tower Shielding Facility, have included measurements of neutron transport in bulk shields of sodium, steel, and inconel and in configurations that simulate lower axial shields, pipe chases, and top-head shields. They have also included measurements of the effects of fuel stored within the reactor vessel and of gamma-ray energy deposition (heating). The paper consists of brief comments on these experiments, and also on a recent experiment in which neutron streaming problems in a Gas-Cooled Fast Breeder Reactor were studied. The need for additional experiments for a few areas of LMFBR shielding is also cited
Numerical analysis of experiments modeling LWR sump cooling by natural convection
International Nuclear Information System (INIS)
2002-01-01
An optional sump cooling concept for the European pressurized water reactor EPR was investigated at the Research Center Karlsruhe. This concept foresees to utilize single phase natural convection in water to remove the decay heat from the core melt. The natural convection was investigated by the SUCOS-2D and -3D scaled experiments. A numerical investigation and interpretation of these experiments was performed by means of the computer code FLUTAN. In this paper, the numerical investigation of SUCOS-3D is summarized. Following the results of the former 2d experiments and the numerical analysis of both experiments, an unexpected temperature distribution is found in this 3d experiment. Basing on the experimental data it had to be postulated that one of the horizontal coolers was slightly tilled against the main flow direction. Additional numerical investigations show that a slope of only one percent would explain the experimental flow field. Conclusions are also drawn on the limits of scalability and transferability of the experimental results to a reactor sump. A detailed transformation will only be possible by applying well validated CFD-codes and experienced code users. As the flow in the reactor sump will be turbulent and this flow is strongly three-dimensional and time-dependent, only the method of Large Eddy Simulation is considered of being an adequate tool for reliable trans formation of the gained experience to analyses for the reactor sump at 1:1 scales. (author)
Analysis of the Source Physics Experiment SPE4 Prime Using State-Of Parallel Numerical Tools.
Vorobiev, O.; Ezzedine, S. M.; Antoun, T.; Glenn, L.
2015-12-01
This work describes a methodology used for large scale modeling of wave propagation from underground chemical explosions conducted at the Nevada National Security Site (NNSS) fractured granitic rock. We show that the discrete natures of rock masses as well as the spatial variability of the fabric of rock properties are very important to understand ground motions induced by underground explosions. In order to build a credible conceptual model of the subsurface we integrated the geological, geomechanical and geophysical characterizations conducted during recent test at the NNSS as well as historical data from the characterization during the underground nuclear test conducted at the NNSS. Because detailed site characterization is limited, expensive and, in some instances, impossible we have numerically investigated the effects of the characterization gaps on the overall response of the system. We performed several computational studies to identify the key important geologic features specific to fractured media mainly the joints characterized at the NNSS. We have also explored common key features to both geological environments such as saturation and topography and assess which characteristics affect the most the ground motion in the near-field and in the far-field. Stochastic representation of these features based on the field characterizations has been implemented into LLNL's Geodyn-L hydrocode. Simulations were used to guide site characterization efforts in order to provide the essential data to the modeling community. We validate our computational results by comparing the measured and computed ground motion at various ranges for the recently executed SPE4 prime experiment. We have also conducted a comparative study between SPE4 prime and previous experiments SPE1 and SPE3 to assess similarities and differences and draw conclusions on designing SPE5.
Rudge, J. F.; Alisic Jewell, L.; Rhebergen, S.; Katz, R. F.; Wells, G. N.
2015-12-01
One of the fundamental components in any dynamical model of melt transport is the rheology of partially molten rock. This rheology is poorly understood, and one way in which a better understanding can be obtained is by comparing the results of laboratory deformation experiments to numerical models. Here we present a comparison between numerical models and the laboratory setup of Qi et al. 2013 (EPSL), where a cylinder of partially molten rock containing rigid spherical inclusions was placed under torsion. We have replicated this setup in a finite element model which solves the partial differential equations describing the mechanical process of compaction. These computationally-demanding 3D simulations are only possible due to the recent development of a new preconditioning method for the equations of magma dynamics. The experiments show a distinct pattern of melt-rich and melt-depleted regions around the inclusions. In our numerical models, the pattern of melt varies with key rheological parameters, such as the ratio of bulk to shear viscosity, and the porosity- and strain-rate-dependence of the shear viscosity. These observed melt patterns therefore have the potential to constrain rheological properties. While there are many similarities between the experiments and the numerical models, there are also important differences, which highlight the need for better models of the physics of two-phase mantle/magma dynamics. In particular, the laboratory experiments display more pervasive melt-rich bands than is seen in our numerics.
International Nuclear Information System (INIS)
Scarani, C.; Tampieri, F.; Tibaldi, S.
1983-01-01
The effect of increasing the resolution of the topography in models of numerical weather prediction is assessed. Different numerical experiments have been performed, referring to a case of cyclogenesis in the lee of the Alps. From the comparison, it appears that the lower atmospheric levels are better described by the model with higherresolution topography; comparable horizontal resolution runs with smoother topography appear to be less satisfactory in this respect. It turns out also that the vertical propagation of the signal due to the front-mountain interaction is faster in the high-resolution experiment
Numerical simulation studies of the LBNL heavy-ion beam combiner experiment
International Nuclear Information System (INIS)
Fawley, W.M.; Seidl, P.; Haber, I.; Friedman, A.; Grote, D.P.
1997-01-01
Transverse beam combining is a cost-saving option employed in many designs for heavy-ion inertial fusion energy drivers. A major area of interest, both theoretically and experimentally, is the resultant transverse phase space dilution during the beam merging process. Currently, a prototype combining experiment is underway at LBNL and we have employed a variety of numerical descriptions to aid in both the initial design of the experiment data. These range from simple envelope codes to detailed 2- and 3-D PIC simulations. We compare the predictions of the different numerical models to each other and to experimental data at different longitudinal positions
International Nuclear Information System (INIS)
Vigneron, Audrey
2015-01-01
The thesis addresses the numerical simulation of non-destructive testing (NDT) using eddy currents, and more precisely the computation of induced electromagnetic fields by a transmitter sensor in a healthy part. This calculation is the first step of the modeling of a complete control process in the CIVA software platform developed at CEA LIST. Currently, models integrated in CIVA are restricted to canonical (modal computation) or axially-symmetric geometries. The need for more diverse and complex configurations requires the introduction of new numerical modeling tools. In practice the sensor may be composed of elements with different shapes and physical properties. The inspected parts are conductive and may contain dielectric or magnetic elements. Due to the cohabitation of different materials in one configuration, different regimes (static, quasi-static or dynamic) may coexist. Under the assumption of linear, isotropic and piecewise homogeneous material properties, the surface integral equation (SIE) approach allows to reduce a volume-based problem to an equivalent surface-based problem. However, the usual SIE formulations for the Maxwell's problem generally suffer from numerical noise in asymptotic situations, and especially at low frequencies. The objective of this study is to determine a version that is stable for a range of physical parameters typical of eddy-current NDT applications. In this context, a block-iterative scheme based on a physical decomposition is proposed for the computation of primary fields. This scheme is accurate and well-conditioned. An asymptotic study of the integral Maxwell's problem at low frequencies is also performed, allowing to establish the eddy-current integral problem as an asymptotic case of the corresponding Maxwell problem. (author) [fr
Numerical experiments to investigate the accuracy of broad-band moment magnitude, Mwp
Hara, Tatsuhiko; Nishimura, Naoki
2011-12-01
We perform numerical experiments to investigate the accuracy of broad-band moment magnitude, Mwp. We conduct these experiments by measuring Mwp from synthetic seismograms and comparing the resulting values to the moment magnitudes used in the calculation of synthetic seismograms. In the numerical experiments using point sources, we have found that there is a significant dependence of Mwp on focal mechanisms, and that depths phases have a large impact on Mwp estimates, especially for large shallow earthquakes. Numerical experiments using line sources suggest that the effects of source finiteness and rupture propagation on Mwp estimates are on the order of 0.2 magnitude units for vertical fault planes with pure dip-slip mechanisms and 45° dipping fault planes with pure dip-slip (thrust) mechanisms, but that the dependence is small for strike-slip events on a vertical fault plane. Numerical experiments for huge thrust faulting earthquakes on a fault plane with a shallow dip angle suggest that the Mwp estimates do not saturate in the moment magnitude range between 8 and 9, although they are underestimates. Our results are consistent with previous studies that compared Mwp estimates to moment magnitudes calculated from seismic moment tensors obtained by analyses of observed data.
Design and implementation of new design of numerical experiments for non linear models
International Nuclear Information System (INIS)
Gazut, St.
2007-03-01
This thesis addresses the problem of the construction of surrogate models in numerical simulation. Whenever numerical experiments are costly, the simulation model is complex and difficult to use. It is important then to select the numerical experiments as efficiently as possible in order to minimize their number. In statistics, the selection of experiments is known as optimal experimental design. In the context of numerical simulation where no measurement uncertainty is present, we describe an alternative approach based on statistical learning theory and re-sampling techniques. The surrogate models are constructed using neural networks and the generalization error is estimated by leave-one-out, cross-validation and bootstrap. It is shown that the bootstrap can control the over-fitting and extend the concept of leverage for non linear in their parameters surrogate models. The thesis describes an iterative method called LDR for Learner Disagreement from experiment Re-sampling, based on active learning using several surrogate models constructed on bootstrap samples. The method consists in adding new experiments where the predictors constructed from bootstrap samples disagree most. We compare the LDR method with other methods of experimental design such as D-optimal selection. (author)
International Nuclear Information System (INIS)
Kiefer, B; Bartel, T; Menzel, A
2012-01-01
Several constitutive models for magnetic shape memory alloys (MSMAs) have been proposed in the literature. The implementation of numerical integration schemes, which allow the prediction of constitutive response for general loading cases and ultimately the incorporation of MSMA response into numerical solution algorithms for fully coupled magneto-mechanical boundary value problems, however, has received only very limited attention. In this work, we establish two algorithmic implementations of the internal variable model for MSMAs proposed in (Kiefer and Lagoudas 2005 Phil. Mag. Spec. Issue: Recent Adv. Theor. Mech. 85 4289–329, Kiefer and Lagoudas 2009 J. Intell. Mater. Syst. 20 143–70), where we restrict our attention to pure martensitic variant reorientation to limit complexity. The first updating scheme is based on the numerical integration of the reorientation strain evolution equation and represents a classical predictor–corrector-type general return mapping algorithm. In the second approach, the inequality-constrained optimization problem associated with internal variable evolution is converted into an unconstrained problem via Fischer–Burmeister complementarity functions and then iteratively solved in standard Newton–Raphson format. Simulations are verified by comparison to closed-form solutions for experimentally relevant loading cases. (paper)
Experiences in integrated leak rate measurements
International Nuclear Information System (INIS)
Shirk, R.E.
1982-01-01
During a hypothetical design basis accident for nuclear power plants, the reactor containment system is relied upon to maintain radioactive exposure limits below acceptable limits. Integrated leak rate testing is a means of verifying that the leakage of radioactivity material from the reactor containment will be below allowable limits. Leakage rate computations are based on the ideal gas law. The absolute method of leakage rate testing utilizing mass point method of data analysis is recommended. Integrated leak rate testing data is obtained from pressure, drybulb temperature, dewpoint temperature, and flow measuring systems. Test data does not support the usual leakage (flow) - pressure square root relationship. The major source of potential leakage from the reactor containment is reactor containment isolation valves
Numerical Modeling of an Integrated Vehicle Fluids System Loop for Pressurizing a Cryogenic Tank
LeClair, A. C.; Hedayat, A.; Majumdar, A. K.
2017-01-01
This paper presents a numerical model of the pressurization loop of the Integrated Vehicle Fluids (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance to reduce system weight and enhance reliability, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) conducted tests to verify the functioning of the IVF system using a flight-like tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to support the test program. This paper presents the simulation of three different test series, comparison of numerical prediction and test data and a novel method of presenting data in a dimensionless form. The paper also presents a methodology of implementing a compressor map in a system level code.
Evaluation of wave power by integrating numerical models and measures at the Port of Civitavecchia
International Nuclear Information System (INIS)
Paladini de Mendoza, Francesco; Bonamano, Simone; Carli, Filippo Maria; Marcelli, Marco; Danelli, Andrea; Peviani, Maximo Aurelio; Burgio, Calogero
2015-01-01
An assessment of the available wave power at regional and local scale was carried out. Two hot spots of higher wave power level were identified and characterized along the coastline of northern Latium Region, near the 'Torre Valdaliga' power plant and in proximity of Civitavecchia’s breakwater, where the presence of a harbour and an electric power plant allows wave energy exploitation. The evaluation process was implemented through measurements, and numerical model assessment and validation. The integration of wave gauges measurements with numerical simulations made it possible to estimate the wave power on the extended area near shore. A down scaling process allowed to proceed from regional to local scale providing increased resolution thanks to highly detailed bathymetry.
On the numerical evaluation of algebro-geometric solutions to integrable equations
International Nuclear Information System (INIS)
Kalla, C; Klein, C
2012-01-01
Physically meaningful periodic solutions to certain integrable partial differential equations are given in terms of multi-dimensional theta functions associated with real Riemann surfaces. Typical analytical problems in the numerical evaluation of these solutions are studied. In the case of hyperelliptic surfaces efficient algorithms exist even for almost degenerate surfaces. This allows the numerical study of solitonic limits. For general real Riemann surfaces, the choice of a homology basis adapted to the anti-holomorphic involution is important for a convenient formulation of the solutions and smoothness conditions. Since existing algorithms for algebraic curves produce a homology basis not related to automorphisms of the curve, we study symplectic transformations to an adapted basis and give explicit formulae for M-curves. As examples we discuss solutions of the Davey–Stewartson and the multi-component nonlinear Schrödinger equations
International Nuclear Information System (INIS)
Castro, P.; Ardao, J.; Velarde, M.; Sedano, L.; Xiberta, J.
2013-01-01
Related with a prospected new scenario of large inventory tritium facilities [KATRIN at TLK, CANDUs, ITER, EAST, other coming] the prescribed dosimetric limits by ICRP-60 for tritium committed-doses are under discussion requiring, in parallel, to surmount the highly conservative assessments by increasing the refinement of dosimetric-assessments in many aspects. Precise Lagrangian-computations of dosimetric cloud-evolution after standardized (normal/incidental/SBO) tritium cloud emissions are today numerically open to the perfect match of real-time meteorological-data, and patterns data at diverse scales for prompt/early and chronic tritium dose assessments. The trends towards integrated-numerical-platforms for environmental-dose assessments of large tritium inventory facilities under development.
International Nuclear Information System (INIS)
Furukawa, Masaru; Ohkawa, Yushiro; Matsuyama, Akinobu
2016-01-01
A high-accuracy numerical integration algorithm for a charged particle motion is developed. The algorithm is based on the Hamiltonian mechanics and the operator decomposition. The algorithm is made to be time-reversal symmetric, and its order of accuracy can be increased to any order by using a recurrence formula. One of the advantages is that it is an explicit method. An effective way to decompose the time evolution operator is examined; the Poisson tensor is decomposed and non-canonical variables are adopted. The algorithm is extended to a time dependent fields' case by introducing the extended phase space. Numerical tests showing the performance of the algorithm are presented. One is the pure cyclotron motion for a long time period, and the other is a charged particle motion in a rapidly oscillating field. (author)
Numerical evaluation of Feynman loop integrals by reduction to tree graphs
International Nuclear Information System (INIS)
Kleinschmidt, T.
2007-12-01
We present a method for the numerical evaluation of loop integrals, based on the Feynman Tree Theorem. This states that loop graphs can be expressed as a sum of tree graphs with additional external on-shell particles. The original loop integral is replaced by a phase space integration over the additional particles. In cross section calculations and for event generation, this phase space can be sampled simultaneously with the phase space of the original external particles. Since very sophisticated matrix element generators for tree graph amplitudes exist and phase space integrations are generically well understood, this method is suited for a future implementation in a fully automated Monte Carlo event generator. A scheme for renormalization and regularization is presented. We show the construction of subtraction graphs which cancel ultraviolet divergences and present a method to cancel internal on-shell singularities. Real emission graphs can be naturally included in the phase space integral of the additional on-shell particles to cancel infrared divergences. As a proof of concept, we apply this method to NLO Bhabha scattering in QED. Cross sections are calculated and are in agreement with results from conventional methods. We also construct a Monte Carlo event generator and present results. (orig.)
Numerical evaluation of Feynman loop integrals by reduction to tree graphs
Energy Technology Data Exchange (ETDEWEB)
Kleinschmidt, T.
2007-12-15
We present a method for the numerical evaluation of loop integrals, based on the Feynman Tree Theorem. This states that loop graphs can be expressed as a sum of tree graphs with additional external on-shell particles. The original loop integral is replaced by a phase space integration over the additional particles. In cross section calculations and for event generation, this phase space can be sampled simultaneously with the phase space of the original external particles. Since very sophisticated matrix element generators for tree graph amplitudes exist and phase space integrations are generically well understood, this method is suited for a future implementation in a fully automated Monte Carlo event generator. A scheme for renormalization and regularization is presented. We show the construction of subtraction graphs which cancel ultraviolet divergences and present a method to cancel internal on-shell singularities. Real emission graphs can be naturally included in the phase space integral of the additional on-shell particles to cancel infrared divergences. As a proof of concept, we apply this method to NLO Bhabha scattering in QED. Cross sections are calculated and are in agreement with results from conventional methods. We also construct a Monte Carlo event generator and present results. (orig.)
Numerical Integration Techniques for Curved-Element Discretizations of Molecule–Solvent Interfaces
Bardhan, Jaydeep P.; Altman, Michael D.; Willis, David J.; Lippow, Shaun M.; Tidor, Bruce; White, Jacob K.
2012-01-01
Surface formulations of biophysical modeling problems offer attractive theoretical and computational properties. Numerical simulations based on these formulations usually begin with discretization of the surface under consideration; often, the surface is curved, possessing complicated structure and possibly singularities. Numerical simulations commonly are based on approximate, rather than exact, discretizations of these surfaces. To assess the strength of the dependence of simulation accuracy on the fidelity of surface representation, we have developed methods to model several important surface formulations using exact surface discretizations. Following and refining Zauhar’s work (J. Comp.-Aid. Mol. Des. 9:149-159, 1995), we define two classes of curved elements that can exactly discretize the van der Waals, solvent-accessible, and solvent-excluded (molecular) surfaces. We then present numerical integration techniques that can accurately evaluate nonsingular and singular integrals over these curved surfaces. After validating the exactness of the surface discretizations and demonstrating the correctness of the presented integration methods, we present a set of calculations that compare the accuracy of approximate, planar-triangle-based discretizations and exact, curved-element-based simulations of surface-generalized-Born (sGB), surface-continuum van der Waals (scvdW), and boundary-element method (BEM) electrostatics problems. Results demonstrate that continuum electrostatic calculations with BEM using curved elements, piecewise-constant basis functions, and centroid collocation are nearly ten times more accurate than planartriangle BEM for basis sets of comparable size. The sGB and scvdW calculations give exceptional accuracy even for the coarsest obtainable discretized surfaces. The extra accuracy is attributed to the exact representation of the solute–solvent interface; in contrast, commonly used planar-triangle discretizations can only offer improved
Direct numerical simulation of the thermal dehydration reaction in a TGA experiment
Lan, S.; Gaeini, M.; Zondag, H.A.; van Steenhoven, A.A.; Rindt, C.C.M.
2018-01-01
This work presents a detailed mathematical model of the coupled mass and heat transfer processes in salt hydrate grains in a TGA experiment. The purpose of developing this numerical model is to get a more fundamental understanding of the influence of parameters like particle size, nucleation rate
Fusion Ignition Research Experiment System Integration
International Nuclear Information System (INIS)
Brown, T.
2000-01-01
This paper describes the current status of the FIRE configuration and the integration of the major subsystem components. FIRE has a major radius of 2 m, a field on axis of 10T, a plasma current of 6.4 MA. It is capable of 18 second pulses when operated with DT and 26 s when operated with DD. The general arrangement consists of sixteen wedged TF coils that surround a free standing central solenoid, a double wall vacuum vessel and internal plasma facing components that are segmented for maintenance through horizontal ports. Large rings located outside the TF coils are used to obtain a load balance between wedging of the intercoil case structure and wedging at the upper/lower inboard corners of the TF coil winding. The magnets are liquid nitrogen cooled and the entire device is surrounded by a thermal enclosure. The double wall vacuum vessel integrates cooling and shielding in a shape that maximizes shielding of ex-vessel components. Within the vacuum vessel, plasma-facing components frame the plasma. First wall tiles are attached directly to inboard and outboard vacuum vessel walls. The divertor is designed for a high triangularity, double-null plasma with a short inner null point-to-wall distance and near vertical outer divertor flux line. The FIRE configuration has been developed to meet the physics objectives and subsystem requirements in an arrangement that allows remote maintenance of in-vessel components and hands-on maintenance of components outside the TF boundary
Kabuth, Alina; Dahmke, Andreas; Hagrey, Said Attia al; Berta, Márton; Dörr, Cordula; Koproch, Nicolas; Köber, Ralf; Köhn, Daniel; Nolde, Michael; Tilmann Pfeiffer, Wolf; Popp, Steffi; Schwanebeck, Malte; Bauer, Sebastian
2016-04-01
Within the framework of the transition to renewable energy sources ("Energiewende"), the German government defined the target of producing 60 % of the final energy consumption from renewable energy sources by the year 2050. However, renewable energies are subject to natural fluctuations. Energy storage can help to buffer the resulting time shifts between production and demand. Subsurface geological structures provide large potential capacities for energy stored in the form of heat or gas on daily to seasonal time scales. In order to explore this potential sustainably, the possible induced effects of energy storage operations have to be quantified for both specified normal operation and events of failure. The ANGUS+ project therefore integrates experimental laboratory studies with numerical approaches to assess subsurface energy storage scenarios and monitoring methods. Subsurface storage options for gas, i.e. hydrogen, synthetic methane and compressed air in salt caverns or porous structures, as well as subsurface heat storage are investigated with respect to site prerequisites, storage dimensions, induced effects, monitoring methods and integration into spatial planning schemes. The conceptual interdisciplinary approach of the ANGUS+ project towards the integration of subsurface energy storage into a sustainable subsurface planning scheme is presented here, and this approach is then demonstrated using the examples of two selected energy storage options: Firstly, the option of seasonal heat storage in a shallow aquifer is presented. Coupled thermal and hydraulic processes induced by periodic heat injection and extraction were simulated in the open-source numerical modelling package OpenGeoSys. Situations of specified normal operation as well as cases of failure in operational storage with leaking heat transfer fluid are considered. Bench-scale experiments provided parameterisations of temperature dependent changes in shallow groundwater hydrogeochemistry. As a
Fundamental aspects of the integration of seismic monitoring with numerical modelling.
CSIR Research Space (South Africa)
Mendecki, AJ
2001-06-01
Full Text Available of the physical state of the rock- mass. ! It must be equipped with the capability of converting the parameters of a real seismic event into a corresponding model-compatible input in the form of an additional loading on the rock-mass. ! It must allow... for an unambiguous identification and quantification of Aseismic events @ among the model-generated data. Structure of an integrated numerical model The functionality interrelations between the different components of a software package designed to implement...
Directory of Open Access Journals (Sweden)
Gemechis File
2012-01-01
Full Text Available We have presented a numerical integration method to solve a class of singularly perturbed delay differential equations with small shift. First, we have replaced the second-order singularly perturbed delay differential equation by an asymptotically equivalent first-order delay differential equation. Then, Simpson’s rule and linear interpolation are employed to get the three-term recurrence relation which is solved easily by discrete invariant imbedding algorithm. The method is demonstrated by implementing it on several linear and nonlinear model examples by taking various values for the delay parameter and the perturbation parameter .
Integrated circuits for particle physics experiments
Snoeys, W; Campbell, M; Cantatore, E; Faccio, F; Heijne, Erik H M; Jarron, Pierre; Kloukinas, Kostas C; Marchioro, A; Moreira, P; Toifl, Thomas H; Wyllie, Ken H
2000-01-01
High energy particle physics experiments investigate the nature of matter through the identification of subatomic particles produced in collisions of protons, electrons, or heavy ions which have been accelerated to very high energies. Future experiments will have hundreds of millions of detector channels to observe the interaction region where collisions take place at a 40 MHz rate. This paper gives an overview of the electronics requirements for such experiments and explains how data reduction, timing distribution, and radiation tolerance in commercial CMOS circuits are achieved for these big systems. As a detailed example, the electronics for the innermost layers of the future tracking detector, the pixel vertex detector, is discussed with special attention to system aspects. A small-scale prototype (130 channels) implemented in standard 0.25 mu m CMOS remains fully functional after a 30 Mrad(SiO/sub 2/) irradiation. A full-scale pixel readout chip containing 8000 readout channels in a 14 by 16 mm/sup 2/ ar...
Integrated vector management: the Zambian experience.
Chanda, Emmanuel; Masaninga, Fred; Coleman, Michael; Sikaala, Chadwick; Katebe, Cecilia; Macdonald, Michael; Baboo, Kumar S; Govere, John; Manga, Lucien
2008-08-27
The Zambian Malaria Control Programme with the Roll Back Malaria (RBM) partners have developed the current National Malaria Strategic Plan (NMSP 2006-2011) which focuses on prevention based on the Integrated Vector Management (IVM) strategy. The introduction and implementation of an IVM strategy was planned in accordance with the World Health Organization (WHO) steps towards IVM implementation namely Introduction Phase, Consolidation Phase and Expansion Phase. IVM has created commitment for Legal and Regulatory policy review, monitoring, Research and a strong stewardship by the chemical suppliers. It has also leveraged additional resources, improved inter-sectoral collaboration, capacity building and enhanced community participation which facilitated a steady scaling up in coverage and utilisation of key preventive interventions. Thus, markedly reducing malaria incidence and case fatalities in the country. Zambia has successfully introduced, consolidated and expanded IVM activities. Resulting in increased coverage and utilization of interventions and markedly reducing malaria-related morbidity and mortality while ensuring a better protection of the environment.
Integrating mental health services: the Finnish experience
Directory of Open Access Journals (Sweden)
Ville Lehtinen
2001-06-01
Full Text Available The aim of this paper is to give a short description of the most important developments of mental health services in Finland during the 1990s, examine their influences on the organisation and provision of services, and describe shortly some national efforts to handle the new situation. The Finnish mental health service system experienced profound changes in the beginning of the 1990s. These included the integration of mental health services, being earlier under own separate administration, with other specialised health services, decentralisation of the financing of health services, and de-institutionalisation of the services. The same time Finland underwent the deepest economic recession in Western Europe, which resulted in cut-offs especially in the mental health budgets. Conducting extensive national research and development programmes in the field of mental health has been one typically Finnish way of supporting the mental health service development. The first of these national programmes was the Schizophrenia Project 1981–97, whose main aims were to decrease the incidence of new long-term patients and the prevalence of old long-stay patients by developing an integrated treatment model. The Suicide Prevention Project 1986–96 aimed at raising awareness of this special problem and decreasing by 20% the proportionally high suicide rate in Finland. The National Depression Programme 1994–98 focused at this clearly increasing public health concern by several research and development project targeted both to the general population and specifically to children, primary care and specialised services. The latest, still on-going Meaningful Life Programme 1998–2003 which main aim is, by multi-sectoral co-operation, to improve the quality of life for people suffering from or living with the threat of mental disorders. Furthermore, the government launched in 1999 a new Goal and Action Programme for Social Welfare and Health Care 2000–2003, in
Majumdar, Alok K.; LeClair, Andre C.; Hedayat, Ali
2016-01-01
This paper presents a numerical model of pressurization of a cryogenic propellant tank for the Integrated Vehicle Fluid (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) has been running tests to verify the functioning of the IVF system using a flight tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to develop an integrated model of the tank and the pressurization system. This paper presents an iterative algorithm for converging the interface boundary conditions between different component models of a large system model. The model results have been compared with test data.
Energy Technology Data Exchange (ETDEWEB)
Pogosyan, T A
1983-01-01
The article is dedicated to the solution of systems of differential equations which describe the transfer processes in an electric power system (EES) by implicit methods of numerical integration. The distinguishing feature of the implicit methods (Euler's reverse method and the trapeze method) is their absolute stability and, consequently, the relatively small accumulation of errors in each step of integration. Therefore, they are found to be very convenient for solving problems of electric power engineering, when the transfer processes are described by a rigid system of differential equations. The rigidity is associated with the range of values of the time constants considered. The advantage of the implicit methods over explicit are shown in a specific example (calculation of the dynamic stability of the simplest electric power system), along with the field of use of the implicit methods and the expedience of their use in power engineering problems.
Numerical Solution of Nonlinear Volterra Integral Equations System Using Simpson’s 3/8 Rule
Directory of Open Access Journals (Sweden)
Adem Kılıçman
2012-01-01
Full Text Available The Simpson’s 3/8 rule is used to solve the nonlinear Volterra integral equations system. Using this rule the system is converted to a nonlinear block system and then by solving this nonlinear system we find approximate solution of nonlinear Volterra integral equations system. One of the advantages of the proposed method is its simplicity in application. Further, we investigate the convergence of the proposed method and it is shown that its convergence is of order O(h4. Numerical examples are given to show abilities of the proposed method for solving linear as well as nonlinear systems. Our results show that the proposed method is simple and effective.
Integrated Networks: National and International Online Experiences
Directory of Open Access Journals (Sweden)
Osvaldo Muniz-Solari
2009-02-01
Full Text Available There is an increasing impression among online geography educators that interaction can be developed based on specific teaching and learning methods. The authors developed a practical research study to investigate this issue. The study was based on advanced graduate courses in geography at Beijing Normal University and Texas State University. International interaction was complemented by online collaboration among the US local group. Both synchronous and asynchronous communication systems were used, which spanned two platforms. Results of this experience indicate that teaching and learning methods must be enhanced by a flexible online learning model and extensive organizational support in order to increase interaction and reach a certain level of cooperation.
Numerical analysis of gas puff modulation experiment on JT-60U
International Nuclear Information System (INIS)
Nagashima, Keisuke; Sakasai, Akira
1992-03-01
In tokamak transport physics, source modulation experiments are one of the most effective methods. For an analysis of these modulation experiments, a simple numerical method was developed to solve the general transport equations. This method was applied to gas puff modulation experiments on JT-60U. From the comparison between the measured and calculated density perturbations, it was found that the particle diffusion coefficient is about 0.8 m 2 /sec in the edge region and 0.1-0.2 m 2 /sec in the central region. (author)
International Nuclear Information System (INIS)
Finsterle, S.; Moridis, G.J.; Pruess, K.; Persoff, P.
1994-01-01
The emplacement of liquids under controlled viscosity conditions is investigated by means of numerical simulations. Design calculations are performed for a laboratory experiment on a decimeter scale, and a field experiment on a meter scale. The purpose of the laboratory experiment is to study the behavior of multiple gout plumes when injected in a porous medium. The calculations for the field trial aim at designing a grout injection test from a vertical well in order to create a grout plume of a significant extent in the subsurface
Dynamics of fault slip near the stability transition combining laboratory and numerical experiments
Mele Veedu, D.; Giorgetti, C.; Scuderi, M. M.; Barbot, S.; Marone, C.; Collettini, C.
2017-12-01
Frictional stability controls the seismogenic potential of faults. Laboratory (1) and theoretical (2) studies document and predict the conditions under which fault slip is seismic or aseismic. However, the full gamut of fault slip behavior near the stable/unstable boundary is still poorly known. Here, we combine insight from laboratory and numerical experiments to identify the wide spectrum of frictional instabilities around that transition, including slow-slip events, period-multiplying events, and chaos. We present a synoptic picture of the dynamics of fault slip in a bifurcation diagram obtained from a series of laboratory and numerical experiments. We compare the laboratory observations with spring-slider and finite-fault numerical models. In the laboratory, we vary the stiffness of the system by modulating the stress field around the experimental fault. In the numerical experiments, we vary the characteristic weakening distance to explore a range of critical nucleation sizes. Contrarily to previously found (3), complex fault dynamics can be obtained with a rate-and-state constitutive law with a single state variable. While the dynamics of fault slip is complicated on large faults by the presence of morphological and rheological heterogeneities, the range of instabilities identified in the laboratory is reminiscent of the variety of slow and fast earthquakes found along subduction zones (4). The accord between laboratory data and theoretical models affords more realistic predictions of fault behavior at slow slip speeds. (1) Scuderi et al., (2016), (2) Ruina (1983), (3) Gu & Wong (1994), (4) Obara & Kato (2016)
Complementarity of integral and differential experiments for reactor physics purposes
International Nuclear Information System (INIS)
Tellier, Henry.
1981-04-01
In this paper, the following topics are studied: uranium 238 effective integral; thermal range uranium 238 capture cross section; Americium 242 m capture cross section. The mentioned examples show that differential and integral experiments are both useful to the reactor physicists
Directory of Open Access Journals (Sweden)
Nikesh S. Dattani
2012-03-01
Full Text Available One of the most successful methods for calculating reduced density operator dynamics in open quantum systems, that can give numerically exact results, uses Feynman integrals. However, when simulating the dynamics for a given amount of time, the number of time steps that can realistically be used with this method is always limited, therefore one often obtains an approximation of the reduced density operator at a sparse grid of points in time. Instead of relying only on ad hoc interpolation methods (such as splines to estimate the system density operator in between these points, I propose a method that uses physical information to assist with this interpolation. This method is tested on a physically significant system, on which its use allows important qualitative features of the density operator dynamics to be captured with as little as two time steps in the Feynman integral. This method allows for an enormous reduction in the amount of memory and CPU time required for approximating density operator dynamics within a desired accuracy. Since this method does not change the way the Feynman integral itself is calculated, the value of the density operator approximation at the points in time used to discretize the Feynamn integral will be the same whether or not this method is used, but its approximation in between these points in time is considerably improved by this method. A list of ways in which this proposed method can be further improved is presented in the last section of the article.
Numerical simulations of a nonequilibrium argon plasma in a shock-tube experiment
Cambier, Jean-Luc
1991-01-01
A code developed for the numerical modeling of nonequilibrium radiative plasmas is applied to the simulation of the propagation of strong ionizing shock waves in argon gas. The simulations attempt to reproduce a series of shock-tube experiments which will be used to validate the numerical models and procedures. The ability to perform unsteady simulations makes it possible to observe some fluctuations in the shock propagation, coupled to the kinetic processes. A coupling mechanism by pressure waves, reminiscent of oscillation mechanisms observed in detonation waves, is described. The effect of upper atomic levels is also briefly discussed.
Integrated vector management: The Zambian experience
Directory of Open Access Journals (Sweden)
Katebe Cecilia
2008-08-01
Full Text Available Abstract Background The Zambian Malaria Control Programme with the Roll Back Malaria (RBM partners have developed the current National Malaria Strategic Plan (NMSP 2006–2011 which focuses on prevention based on the Integrated Vector Management (IVM strategy. The introduction and implementation of an IVM strategy was planned in accordance with the World Health Organization (WHO steps towards IVM implementation namely Introduction Phase, Consolidation Phase and Expansion Phase. Achievements IVM has created commitment for Legal and Regulatory policy review, monitoring, Research and a strong stewardship by the chemical suppliers. It has also leveraged additional resources, improved inter-sectoral collaboration, capacity building and enhanced community participation which facilitated a steady scaling up in coverage and utilisation of key preventive interventions. Thus, markedly reducing malaria incidence and case fatalities in the country. Conclusion Zambia has successfully introduced, consolidated and expanded IVM activities. Resulting in increased coverage and utilization of interventions and markedly reducing malaria-related morbidity and mortality while ensuring a better protection of the environment.
The integrated project as a learning experience
Directory of Open Access Journals (Sweden)
Maria Angeles Antequera
2012-03-01
Full Text Available Florida is a higher education centre specialising in technical and business training. Postgraduate programs, university qualifications, vocational training, secondary education, further education, occupational training and languages are taught at Florida. An educational model in accordance with the demands of the European Higher Education Area has been designed, focussing on teaching for professional competencies. We have chosen to use a methodology which promotes the development of skills and abilities, it promotes participation and it is student-centric as s/he must look for knowledge him/herself thus connecting the educational and the real world. In the different university degrees taught in our centre, each year the student carries out a project set in a real context which integrates specific competencies from the course subject and develops transversal competencies associated with the project which are the purpose of planning and progressive learning: team work, effective communication, conflict resolution, leadership skills, innovation and creativity. The IP counts for 25% of each course in terms of objectives, scheduling and final evaluation. The project grade is an individual grade for each student and is the same for all subjects which form part of the project.
Numerical Modelling of Mechanical Integrity of the Copper-Cast Iron Canister. A Literature Review
International Nuclear Information System (INIS)
Lanru Jing
2004-04-01
This review article presents a summary of the research works on the numerical modelling of the mechanical integrity of the composite copper-cast iron canisters for the final disposal of Swedish nuclear wastes, conducted by SKB and SKI since 1992. The objective of the review is to evaluate the outstanding issues existing today about the basic design concepts and premises, fundamental issues on processes, properties and parameters considered for the functions and requirements of canisters under the conditions of a deep geological repository. The focus is placed on the adequacy of numerical modelling approaches adopted in regards to the overall mechanical integrity of the canisters, especially the initial state of canisters regarding defects and the consequences of their evolution under external and internal loading mechanisms adopted in the design premises. The emphasis is the stress-strain behaviour and failure/strength, with creep and plasticity involved. Corrosion, although one of the major concerns in the field of canister safety, was not included
Numerical simulation of a lattice polymer model at its integrable point
International Nuclear Information System (INIS)
Bedini, A; Owczarek, A L; Prellberg, T
2013-01-01
We revisit an integrable lattice model of polymer collapse using numerical simulations. This model was first studied by Blöte and Nienhuis (1989 J. Phys. A: Math. Gen. 22 1415) and it describes polymers with some attraction, providing thus a model for the polymer collapse transition. At a particular set of Boltzmann weights the model is integrable and the exponents ν = 12/23 ≈ 0.522 and γ = 53/46 ≈ 1.152 have been computed via identification of the scaling dimensions x t = 1/12 and x h = −5/48. We directly investigate the polymer scaling exponents via Monte Carlo simulations using the pruned-enriched Rosenbluth method algorithm. By simulating this polymer model for walks up to length 4096 we find ν = 0.576(6) and γ = 1.045(5), which are clearly different from the predicted values. Our estimate for the exponent ν is compatible with the known θ-point value of 4/7 and in agreement with very recent numerical evaluation by Foster and Pinettes (2012 J. Phys. A: Math. Theor. 45 505003). (paper)
Numerical investigation of premixed combustion in a porous burner with integrated heat exchanger
Energy Technology Data Exchange (ETDEWEB)
Farzaneh, Meisam; Shafiey, Mohammad; Shams, Mehrzad [K.N. Toosi University of Technology, Department of Mechanical Engineering, Tehran (Iran, Islamic Republic of); Ebrahimi, Reza [K.N. Toosi University of Technology, Department of Aerospace Engineering, Tehran (Iran, Islamic Republic of)
2012-07-15
In this paper, we perform a numerical analysis of a two-dimensional axisymmetric problem arising in premixed combustion in a porous burner with integrated heat exchanger. The physical domain consists of two zones, porous and heat exchanger zones. Two dimensional Navier-Stokes equations, gas and solid energy equations, and chemical species transport equations are solved and heat release is described by a multistep kinetics mechanism. The solid matrix is modeled as a gray medium, and the finite volume method is used to solve the radiative transfer equation to calculate the local radiation source/sink in the solid phase energy equation. Special attention is given to model heat transfer between the hot gas and the heat exchanger tube. Thus, the corresponding terms are added to the energy equations of the flow and the solid matrix. Gas and solid temperature profiles and species mole fractions on the burner centerline, predicted 2D temperature fields, species concentrations and streamlines are presented. Calculated results for temperature profiles are compared to experimental data. It is shown that there is good agreement between the numerical solutions and the experimental data and it is concluded that the developed numerical program is an excellent tool to investigate combustion in porous burner. (orig.)
Application of Numerical Integration and Data Fusion in Unit Vector Method
Zhang, J.
2012-01-01
The Unit Vector Method (UVM) is a series of orbit determination methods which are designed by Purple Mountain Observatory (PMO) and have been applied extensively. It gets the conditional equations for different kinds of data by projecting the basic equation to different unit vectors, and it suits for weighted process for different kinds of data. The high-precision data can play a major role in orbit determination, and accuracy of orbit determination is improved obviously. The improved UVM (PUVM2) promoted the UVM from initial orbit determination to orbit improvement, and unified the initial orbit determination and orbit improvement dynamically. The precision and efficiency are improved further. In this thesis, further research work has been done based on the UVM: Firstly, for the improvement of methods and techniques for observation, the types and decision of the observational data are improved substantially, it is also asked to improve the decision of orbit determination. The analytical perturbation can not meet the requirement. So, the numerical integration for calculating the perturbation has been introduced into the UVM. The accuracy of dynamical model suits for the accuracy of the real data, and the condition equations of UVM are modified accordingly. The accuracy of orbit determination is improved further. Secondly, data fusion method has been introduced into the UVM. The convergence mechanism and the defect of weighted strategy have been made clear in original UVM. The problem has been solved in this method, the calculation of approximate state transition matrix is simplified and the weighted strategy has been improved for the data with different dimension and different precision. Results of orbit determination of simulation and real data show that the work of this thesis is effective: (1) After the numerical integration has been introduced into the UVM, the accuracy of orbit determination is improved obviously, and it suits for the high-accuracy data of
The regional energy integration: the latin-american experiences
International Nuclear Information System (INIS)
2003-01-01
The ways of the regional economic integrations are not identical and generate different repercussions on the markets and the energy industries evolution. The example of the Latin America proposes many various experiences to evaluate the stakes and the limits of each regional integrations. These limits lead to solution researches including indisputable convergencies. The first part of this document presents the genesis of these regional economic integrations experiences in Latina America, to study in the second part the energy consequences of the liberal ALENA and of the more political MERCOSUR. (A.L.B.)
Kelly, N. M.; Marchi, S.; Mojzsis, S. J.; Flowers, R. M.; Metcalf, J. R.; Bottke, W. F., Jr.
2017-12-01
Impacts have a significant physical and chemical influence on the surface conditions of a planet. The cratering record is used to understand a wide array of impact processes, such as the evolution of the impact flux through time. However, the relationship between impactor size and a resulting impact crater remains controversial (e.g., Bottke et al., 2016). Likewise, small variations in the impact velocity are known to significantly affect the thermal-mechanical disturbances in the aftermath of a collision. Development of more robust numerical models for impact cratering has implications for how we evaluate the disruptive capabilities of impact events, including the extent and duration of thermal anomalies, the volume of ejected material, and the resulting landscape of impacted environments. To address uncertainties in crater scaling relationships, we present an approach and methodology that integrates numerical modeling of the thermal evolution of terrestrial impact craters with low-temperature, (U-Th)/He thermochronometry. The approach uses time-temperature (t-T) paths of crust within an impact crater, generated from numerical simulations of an impact. These t-T paths are then used in forward models to predict the resetting behavior of (U-Th)/He ages in the mineral chronometers apatite and zircon. Differences between the predicted and measured (U-Th)/He ages from a modeled terrestrial impact crater can then be used to evaluate parameters in the original numerical simulations, and refine the crater scaling relationships. We expect our methodology to additionally inform our interpretation of impact products, such as lunar impact breccias and meteorites, providing robust constraints on their thermal histories. In addition, the method is ideal for sample return mission planning - robust "prediction" of ages we expect from a given impact environment enhances our ability to target sampling sites on the Moon, Mars or other solar system bodies where impacts have strongly
International Nuclear Information System (INIS)
Takeda, H.; Isha, H.
1981-01-01
The paper is concerned with the displacement-assumed-finite elements by applying the reduced numerical integration technique in structural problems. The first part is a general consideration on the technique. Its purpose is to examine a variational interpretation of the finite element displacement formulation with the reduced integration technique in structural problems. The formulation is critically studied from a standpoint of the natural stiffness approach. It is shown that these types of elements are equivalent to a certain type of displacement and stress assumed mixed elements. The rank deficiency of the stiffness matrix of these elements is interpreted as a problem in the transformation from the natural system to a Cartesian system. It will be shown that a variational basis of the equivalent mixed formulation is closely related to the Hellinger-Reissner's functional. It is presented that for simple elements, e.g. bilinear quadrilateral plane stress and plate bending there are corresponding mixed elements from the functional. For relatively complex types of these elements, it is shown that they are equivalent to localized mixed elements from the Hellinger-Reissner's functional. In the second part, typical finite elements with the reduced integration technique are studied to demonstrate this equivalence. A bilinear displacement and rotation assumed shear beam element, a bilinear displacement assumed quadrilateral plane stress element and a bilinear deflection and rotation assumed quadrilateral plate bending element are examined to present equivalent mixed elements. Not only the theoretical consideration is presented but numerical studies are shown to demonstrate the effectiveness of these elements in practical analysis. (orig.)
Numerical investigation of two interacting parallel thruster-plumes and comparison to experiment
Grabe, Martin; Holz, André; Ziegenhagen, Stefan; Hannemann, Klaus
2014-12-01
Clusters of orbital thrusters are an attractive option to achieve graduated thrust levels and increased redundancy with available hardware, but the heavily under-expanded plumes of chemical attitude control thrusters placed in close proximity will interact, leading to a local amplification of downstream fluxes and of back-flow onto the spacecraft. The interaction of two similar, parallel, axi-symmetric cold-gas model thrusters has recently been studied in the DLR High-Vacuum Plume Test Facility STG under space-like vacuum conditions, employing a Patterson-type impact pressure probe with slot orifice. We reproduce a selection of these experiments numerically, and emphasise that a comparison of numerical results to the measured data is not straight-forward. The signal of the probe used in the experiments must be interpreted according to the degree of rarefaction and local flow Mach number, and both vary dramatically thoughout the flow-field. We present a procedure to reconstruct the probe signal by post-processing the numerically obtained flow-field data and show that agreement to the experimental results is then improved. Features of the investigated cold-gas thruster plume interaction are discussed on the basis of the numerical results.
Numerical Experiments on Advective Transport in Large Three-Dimensional Discrete Fracture Networks
Makedonska, N.; Painter, S. L.; Karra, S.; Gable, C. W.
2013-12-01
Modeling of flow and solute transport in discrete fracture networks is an important approach for understanding the migration of contaminants in impermeable hard rocks such as granite, where fractures provide dominant flow and transport pathways. The discrete fracture network (DFN) model attempts to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. An integrated DFN meshing [1], flow, and particle tracking [2] simulation capability that enables accurate flow and particle tracking simulation on large DFNs has recently been developed. The new capability has been used in numerical experiments on advective transport in large DFNs with tens of thousands of fractures and millions of computational cells. The modeling procedure starts from the fracture network generation using a stochastic model derived from site data. A high-quality computational mesh is then generated [1]. Flow is then solved using the highly parallel PFLOTRAN [3] code. PFLOTRAN uses the finite volume approach, which is locally mass conserving and thus eliminates mass balance problems during particle tracking. The flow solver provides the scalar fluxes on each control volume face. From the obtained fluxes the Darcy velocity is reconstructed for each node in the network [4]. Velocities can then be continuously interpolated to any point in the domain of interest, thus enabling random walk particle tracking. In order to describe the flow field on fractures intersections, the control volume cells on intersections are split into four planar polygons, where each polygon corresponds to a piece of a fracture near the intersection line. Thus
International Nuclear Information System (INIS)
Fujii, Naoki; Ikeno, Masaaki; Sakakiyama, Tsutomu; Matsuyama, Masafumi; Takao, Makoto; Mukohara, Takeshi
2009-01-01
Numerical model of topography change is important to examine collapse of the harbor facilities by sand transport due to tsunami. Problems for evaluation of sand transport due to tsunami with topography change model are in precision of the numerical model and topography change data. Therefore, we installed the harbor in large-scaled wave tank and carried out experiment about tsunami flow and topography change to get those detailed data. For results provided by experimental test, we applied the topography change model of Ikeno et al. (2009a) and evaluated it about the reproduction characteristics. As a result, it was confirmed that reproduction of an experiment improved by using new pickup rate formula proposed by Ikeno et al. (2009a). (author)
International Nuclear Information System (INIS)
Xie Ruoze; Zhong Weizhou; Wan Qiang; Huang Xicheng; Zhang Fangju
2015-01-01
The drop impact process of multilayer-combinational container was simulated experimentally using a gas gun, and the normal impact and oblique impact of scaled models were tested. The experiments of scaled models were simulated numerically, and the stress distribution and plastic deformation in the tested structures during collision process were obtained. The results were compared with the experiment data. It was shown that the impact work mainly converted into plastic work due to the plastic deformation of the cushion wood and the plastic hinge in the buckled steel shell. The plastic deformation mainly happened at the collided end of the scaled models, and there was no plastic deformation found far from the collided end. The compressive stress-strain curve of the wood in texture direction can be used to simulate numerically the drop impact process of multilayer-combinational container. (authors)
Numerical simulations of inertial confinement fusion hohlraum with LARED-integration code
International Nuclear Information System (INIS)
Li Jinghong; Li Shuanggui; Zhai Chuanlei
2011-01-01
In the target design of the Inertial Confinement Fusion (ICF) program, it is common practice to apply radiation hydrodynamics code to study the key physical processes happened in ICF process, such as hohlraum physics, radiation drive symmetry, capsule implosion physics in the radiation-drive approach of ICF. Recently, many efforts have been done to develop our 2D integrated simulation capability of laser fusion with a variety of optional physical models and numerical methods. In order to effectively integrate the existing codes and to facilitate the development of new codes, we are developing an object-oriented structured-mesh parallel code-supporting infrastructure, called JASMIN. Based on two-dimensional three-temperature hohlraum physics code LARED-H and two-dimensional multi-group radiative transfer code LARED-R, we develop a new generation two-dimensional laser fusion code under the JASMIN infrastructure, which enable us to simulate the whole process of laser fusion from the laser beams' entrance into the hohlraum to the end of implosion. In this paper, we will give a brief description of our new-generation two-dimensional laser fusion code, named LARED-Integration, especially in its physical models, and present some simulation results of holhraum. (author)
Engineering Physics Division integral experiments and their analyses
International Nuclear Information System (INIS)
Anon.
1980-01-01
Integral experiments are performed as part of the Engineering Physics Division's on-going research in the development and application of radiation shielding methods. Integral experiments performed at the Oak Ridge Electron Linear Accelerator (ORELA) under the Division's Magnetic Fusion program are designed to provide data against which ORNL and all other organizations involved in shielding calculations for fusion devices can test their calculational methods and interaction data. The Tower Shielding Facility (TSF) continues to be the primary source of integral data for fission reactor shielding design. The experiments performed at the TSF during the last few years have been sponsored by the Gas Cooled Fast Reactor (GCFR) program. During this report period final documentation was also prepared for the remaining LMFBR shielding experiments, including an examination of streaming through annular slits and measurement of secondary gamma-ray production in reinforced concrete
Energy Technology Data Exchange (ETDEWEB)
NONE
2003-07-01
The ways of the regional economic integrations are not identical and generate different repercussions on the markets and the energy industries evolution. The example of the Latin America proposes many various experiences to evaluate the stakes and the limits of each regional integrations. These limits lead to solution researches including indisputable convergencies. The first part of this document presents the genesis of these regional economic integrations experiences in Latina America, to study in the second part the energy consequences of the liberal ALENA and of the more political MERCOSUR. (A.L.B.)
Energy Technology Data Exchange (ETDEWEB)
NONE
2003-07-01
The ways of the regional economic integrations are not identical and generate different repercussions on the markets and the energy industries evolution. The example of the Latin America proposes many various experiences to evaluate the stakes and the limits of each regional integrations. These limits lead to solution researches including indisputable convergencies. The first part of this document presents the genesis of these regional economic integrations experiences in Latina America, to study in the second part the energy consequences of the liberal ALENA and of the more political MERCOSUR. (A.L.B.)
Absence of visual experience modifies the neural basis of numerical thinking.
Kanjlia, Shipra; Lane, Connor; Feigenson, Lisa; Bedny, Marina
2016-10-04
In humans, the ability to reason about mathematical quantities depends on a frontoparietal network that includes the intraparietal sulcus (IPS). How do nature and nurture give rise to the neurobiology of numerical cognition? We asked how visual experience shapes the neural basis of numerical thinking by studying numerical cognition in congenitally blind individuals. Blind (n = 17) and blindfolded sighted (n = 19) participants solved math equations that varied in difficulty (e.g., 27 - 12 = x vs. 7 - 2 = x), and performed a control sentence comprehension task while undergoing fMRI. Whole-cortex analyses revealed that in both blind and sighted participants, the IPS and dorsolateral prefrontal cortices were more active during the math task than the language task, and activity in the IPS increased parametrically with equation difficulty. Thus, the classic frontoparietal number network is preserved in the total absence of visual experience. However, surprisingly, blind but not sighted individuals additionally recruited a subset of early visual areas during symbolic math calculation. The functional profile of these "visual" regions was identical to that of the IPS in blind but not sighted individuals. Furthermore, in blindness, number-responsive visual cortices exhibited increased functional connectivity with prefrontal and IPS regions that process numbers. We conclude that the frontoparietal number network develops independently of visual experience. In blindness, this number network colonizes parts of deafferented visual cortex. These results suggest that human cortex is highly functionally flexible early in life, and point to frontoparietal input as a mechanism of cross-modal plasticity in blindness.
Pline, Alexander D.; Werner, Mark P.; Hsieh, Kwang-Chung
1991-01-01
The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the United States Microgravity Laboratory-1 (USML-1) Spacelab mission planned for June, 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electric, two dimensional Particle Image Velocimetry (PIV) technique called Particle Displacement Tracking (PDT), which uses a simple space domain particle tracking algorithm. Results using the ground based STDCE hardware, with a radiant flux heating mode, and the PDT system are compared to numerical solutions obtained by solving the axisymmetric Navier Stokes equations with a deformable free surface. The PDT technique is successful in producing a velocity vector field and corresponding stream function from the raw video data which satisfactorily represents the physical flow. A numerical program is used to compute the velocity field and corresponding stream function under identical conditions. Both the PDT system and numerical results were compared to a streak photograph, used as a benchmark, with good correlation.
International Nuclear Information System (INIS)
Artemov, A.S.
1996-01-01
The values and nature of systematic errors in small-angle particle scattering experiments using ribbon-like beams are investigated by numerical simulation. As shown, the extent of the influence of a ribbon geometry of experiment on the result of measurement is significantly dependent on the shape of the measured angular distribution in an elementary act of interaction. The algorithm of experimental material treatment, obtained in measuring the widths at half maximum of the angular differential cross sections of secondary particles, is presented using an example of specific distributions and certain experimental setup. (author). 12 refs., 7 figs
Numerical simulation of CALIBAN reactivity perturbation experiments using neptunium-237 samples
International Nuclear Information System (INIS)
Humbert, Philippe; Mechitoua, Boukhmes
2003-01-01
In order to contribute to the validation of nuclear data used in critical mass computation, reactivity perturbation experiments using 237 Np samples have been performed at CEA-Valduc using the fast pulsed reactor CALIBAN operated in continuous mode. In this paper we report these experiments together with the numerical calculations. The calculations were carried out using PANDA, a S N code developed at CEA-Bruyeres-le-Chatel for classic criticality and stochastic neutronics applications and with MCNP4C which is a commonly used Monte Carlo code. A good agreement was found between experimental and deterministic results. (author)
Energy Technology Data Exchange (ETDEWEB)
Ploskic, Adnan; Holmberg, Sture [Fluid and Climate Technology, School of Architecture and Built Environment, KTH, Marinens vaeg 30, SE-13640 Handen, Stockholm (Sweden)
2011-01-15
The functioning of a hydronic baseboard heating system with integrated air supply was analyzed. The aim was to investigate thermal performance of the system when cold outdoor (ventilation) airflow was forced through the baseboard heater. The performance of the system was evaluated for different ventilation rates at typical outdoor temperatures during the Swedish winter season. Three different analytical models and Computational Fluid Dynamics (CFD) were used to predict the temperature rise of the airflow inside the baseboard heater. Good agreement between numerical (CFD) and analytical calculations was obtained. Calculations showed that it was fully possible to pre-heat the incoming airflow to the indoor temperature and to cover transmission losses, using 45 C supply water flow. The analytical calculations also showed that the airflow per supply opening in the baseboard heater needed to be limited to 7.0 l/s due to pressure losses inside the channel. At this ventilation rate, the integrated system with one air supply gave about 2.1 more heat output than a conventional baseboard heating system. CFD simulations also showed that the integrated system was capable of countering downdraught created by 2.0 m high glazed areas and a cold outdoor environment. Draught discomfort in the case with the conventional system was slightly above the recommended upper limit, but heat distribution across whole analyzed office space was uniform for both heating systems. It was concluded that low-temperature baseboard heating systems with integrated air supply can meet both international comfort requirements, and lead to energy savings in cold climates. (author)
Numerical path integral solution to strong Coulomb correlation in one dimensional Hooke's atom
Ruokosenmäki, Ilkka; Gholizade, Hossein; Kylänpää, Ilkka; Rantala, Tapio T.
2017-01-01
We present a new approach based on real time domain Feynman path integrals (RTPI) for electronic structure calculations and quantum dynamics, which includes correlations between particles exactly but within the numerical accuracy. We demonstrate that incoherent propagation by keeping the wave function real is a novel method for finding and simulation of the ground state, similar to Diffusion Monte Carlo (DMC) method, but introducing new useful tools lacking in DMC. We use 1D Hooke's atom, a two-electron system with very strong correlation, as our test case, which we solve with incoherent RTPI (iRTPI) and compare against DMC. This system provides an excellent test case due to exact solutions for some confinements and because in 1D the Coulomb singularity is stronger than in two or three dimensional space. The use of Monte Carlo grid is shown to be efficient for which we determine useful numerical parameters. Furthermore, we discuss another novel approach achieved by combining the strengths of iRTPI and DMC. We also show usefulness of the perturbation theory for analytical approximates in case of strong confinements.
Ramo, Nicole L.; Puttlitz, Christian M.
2018-01-01
Compelling evidence that many biological soft tissues display both strain- and time-dependent behavior has led to the development of fully non-linear viscoelastic modeling techniques to represent the tissue’s mechanical response under dynamic conditions. Since the current stress state of a viscoelastic material is dependent on all previous loading events, numerical analyses are complicated by the requirement of computing and storing the stress at each step throughout the load history. This requirement quickly becomes computationally expensive, and in some cases intractable, for finite element models. Therefore, we have developed a strain-dependent numerical integration approach for capturing non-linear viscoelasticity that enables calculation of the current stress from a strain-dependent history state variable stored from the preceding time step only, which improves both fitting efficiency and computational tractability. This methodology was validated based on its ability to recover non-linear viscoelastic coefficients from simulated stress-relaxation (six strain levels) and dynamic cyclic (three frequencies) experimental stress-strain data. The model successfully fit each data set with average errors in recovered coefficients of 0.3% for stress-relaxation fits and 0.1% for cyclic. The results support the use of the presented methodology to develop linear or non-linear viscoelastic models from stress-relaxation or cyclic experimental data of biological soft tissues. PMID:29293558
A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges
Directory of Open Access Journals (Sweden)
Paolo Lonetti
2016-10-01
Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes
Coevolution of bed surface patchiness and channel morphology: 2. Numerical experiments
Nelson, Peter A.; McDonald, Richard R.; Nelson, Jonathan M.; Dietrich, William E.
2015-01-01
In gravel bed rivers, bed topography and the bed surface grain size distribution evolve simultaneously, but it is not clear how feedbacks between topography and grain sorting affect channel morphology. In this, the second of a pair of papers examining interactions between bed topography and bed surface sorting in gravel bed rivers, we use a two-dimensional morphodynamic model to perform numerical experiments designed to explore the coevolution of both free and forced bars and bed surface patches. Model runs were carried out on a computational grid simulating a 200 m long, 2.75 m wide, straight, rectangular channel, with an initially flat bed at a slope of 0.0137. Over five numerical experiments, we varied (a) whether an obstruction was present, (b) whether the sediment was a gravel mixture or a single size, and (c) whether the bed surface grain size feeds back on the hydraulic roughness field. Experiments with channel obstructions developed a train of alternate bars that became stationary and were connected to the obstruction. Freely migrating alternate bars formed in the experiments without channel obstructions. Simulations incorporating roughness feedbacks between the bed surface and flow field produced flatter, broader, and longer bars than simulations using constant roughness or uniform sediment. Our findings suggest that patches are not simply a by-product of bed topography, but they interact with the evolving bed and influence morphologic evolution.
Observation and Numerical Experiments for Drag Coefficient Under Typhoon Wind Forcing
Institute of Scientific and Technical Information of China (English)
CAO Huiqiu; ZHOU Liangming; LI Shuiqing; WANG Zhifeng
2017-01-01
This paper presents a study on drag coefficients under typhoon wind forcing based on observations and numerical experiments.The friction velocity and wind speed are measured at a marine observation platform in the South China Sea.Three typhoons:SOULIK (2013),TRAMI (2013) and FITOW (2013) are observed at a buoy station in the northeast sea area of Pingtan Island.A new parameterization is formulated for the wind drag coefficient as a function of wind speed.It is found that the drag coefficient (Ca) increases linearly with the slope of 0.083× 10-3 for wind speed less than 24 m s-1.To investigate the drag coefficient under higher wind conditions,three numerical experiments are implemented for these three typhoons using SWAN wave model.The wind input data are objective reanalysis datasets,which are assimilated with many sources and provided every six hours with the resolution of 0.125° ×0.125°.The numerical simulation results show a good agreement with wave observation data under typhoon wind forcing.The results indicate that the drag coefficient levels off with the linear slope of 0.012× 10-3 for higher wind speeds (less than 34 m s-1) and the new parameterization improvese the simulation accuracy compared with the Wu (1982) default used in SWAN.
International Nuclear Information System (INIS)
Figueroa, Aldo; Meunier, Patrice; Villermaux, Emmanuel; Cuevas, Sergio; Ramos, Eduardo
2014-01-01
We present a combination of experiment, theory, and modelling on laminar mixing at large Péclet number. The flow is produced by oscillating electromagnetic forces in a thin electrolytic fluid layer, leading to oscillating dipoles, quadrupoles, octopoles, and disordered flows. The numerical simulations are based on the Diffusive Strip Method (DSM) which was recently introduced (P. Meunier and E. Villermaux, “The diffusive strip method for scalar mixing in two-dimensions,” J. Fluid Mech. 662, 134–172 (2010)) to solve the advection-diffusion problem by combining Lagrangian techniques and theoretical modelling of the diffusion. Numerical simulations obtained with the DSM are in reasonable agreement with quantitative dye visualization experiments of the scalar fields. A theoretical model based on log-normal Probability Density Functions (PDFs) of stretching factors, characteristic of homogeneous turbulence in the Batchelor regime, allows to predict the PDFs of scalar in agreement with numerical and experimental results. This model also indicates that the PDFs of scalar are asymptotically close to log-normal at late stages, except for the large concentration levels which correspond to low stretching factors
Numerical functional integration method for studying the properties of the physical vacuum
International Nuclear Information System (INIS)
Lobanov, Yu.Yu.
1998-01-01
The new approach to investigate the physical vacuum in quantum theories including its nonperturbative topological structure is discussed. This approach is based on the representation of the matrix element of the evolution operator in Euclidean metrics in a form of the functional integral with a certain measure in the corresponding space and on the use of approximation formulas which we constructed for this kind of integral. No preliminary discretization of space and time is required, as well as no simplifying assumptions like semiclassical approximation, collective excitations, introduction of ''short-time'' propagators, etc. are necessary in this approach. The method allows to use the more preferable deterministic algorithms instead of the traditional stochastic technique. It has been proven that our approach has important advantages over the other known methods, including the higher efficiency of computations. Examples of application of the method to the numerical study of some potential nuclear models and to the computation of the topological susceptibility and the θ-vacua energy are presented. (author)
An integrated numerical and physical modeling system for an enhanced in situ bioremediation process
International Nuclear Information System (INIS)
Huang, Y.F.; Huang, G.H.; Wang, G.Q.; Lin, Q.G.; Chakma, A.
2006-01-01
Groundwater contamination due to releases of petroleum products is a major environmental concern in many urban districts and industrial zones. Over the past years, a few studies were undertaken to address in situ bioremediation processes coupled with contaminant transport in two- or three-dimensional domains. However, they were concentrated on natural attenuation processes for petroleum contaminants or enhanced in situ bioremediation processes in laboratory columns. In this study, an integrated numerical and physical modeling system is developed for simulating an enhanced in situ biodegradation (EISB) process coupled with three-dimensional multiphase multicomponent flow and transport simulation in a multi-dimensional pilot-scale physical model. The designed pilot-scale physical model is effective in tackling natural attenuation and EISB processes for site remediation. The simulation results demonstrate that the developed system is effective in modeling the EISB process, and can thus be used for investigating the effects of various uncertainties. - An integrated modeling system was developed to enhance in situ bioremediation processes
Numerical integration methods and layout improvements in the context of dynamic RNA visualization.
Shabash, Boris; Wiese, Kay C
2017-05-30
RNA visualization software tools have traditionally presented a static visualization of RNA molecules with limited ability for users to interact with the resulting image once it is complete. Only a few tools allowed for dynamic structures. One such tool is jViz.RNA. Currently, jViz.RNA employs a unique method for the creation of the RNA molecule layout by mapping the RNA nucleotides into vertexes in a graph, which we call the detailed graph, and then utilizes a Newtonian mechanics inspired system of forces to calculate a layout for the RNA molecule. The work presented here focuses on improvements to jViz.RNA that allow the drawing of RNA secondary structures according to common drawing conventions, as well as dramatic run-time performance improvements. This is done first by presenting an alternative method for mapping the RNA molecule into a graph, which we call the compressed graph, and then employing advanced numerical integration methods for the compressed graph representation. Comparing the compressed graph and detailed graph implementations, we find that the compressed graph produces results more consistent with RNA drawing conventions. However, we also find that employing the compressed graph method requires a more sophisticated initial layout to produce visualizations that would require minimal user interference. Comparing the two numerical integration methods demonstrates the higher stability of the Backward Euler method, and its resulting ability to handle much larger time steps, a high priority feature for any software which entails user interaction. The work in this manuscript presents the preferred use of compressed graphs to detailed ones, as well as the advantages of employing the Backward Euler method over the Forward Euler method. These improvements produce more stable as well as visually aesthetic representations of the RNA secondary structures. The results presented demonstrate that both the compressed graph representation, as well as the Backward
A study on experiment and numerical simulation of heat exchanger in heating furnace
Directory of Open Access Journals (Sweden)
Z. C. Lv
2018-01-01
Full Text Available In this paper, air preheater is used the research object and its heat transfer law is studied by experiment and numerical simulation. The experimental data showed that with the increases of inlet air velocity, the comprehensive heat transfer coefficient and heat transfer efficiency increase, but the temperature efficiency decreases and the resistance loss on the air side increases. The numerical simulation results showed that the larger the diameter of the tube, the better the heat transfer effect. When horizontal spacing in the range of 290 - 305 mm and longitudinal spacing is 70 - 90 mm, the heat transfer effect is best. The optimized heat exchanger structure is that diameter is 60 mm, horizontal spacing is 300 mm, longitudinal spacing is 90 mm. As the inlet air flow rate increases, the heat transfer efficiency increases, but the temperature efficiency decreases and the resistance loss on the air side increases.
A method for solving the KDV equation and some numerical experiments
International Nuclear Information System (INIS)
Chang Jinjiang.
1993-01-01
In this paper, by means of difference method for discretization of space partial derivatives of KDV equation, an initial value problem in ordinary differential equations of large dimensions is produced. By using this ordinary differential equations the existence and the uniqueness of the solution of the KDV equation and the conservation of scheme are proved. This ordinary differential equation can be solved by using implicit Runge-Kutta methods, so a new method for finding the numerical solution of the KDV equation is presented. Numerical experiments not only describe in detail the procedure of two solitons collision, soliton reflex and soliton produce, but also show that this method is very effective. (author). 7 refs, 3 figs
Numerical simulation of MH growth/dissociation by hot water injection on the Lab. experiment
Temma, N.; Sakamoto, Y.; Komai, T.; Yamaguchi, T.; Pawar, R.; Zyvoloski, G.
2005-12-01
Methane Hydrate (MH) is considered to be one of the new-generation energy resources. Aiming to develop the method of extraction of methane gas from MH, laboratory experiments have been performed in order to grasp the MH property in the National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba in Japan. In this paper, we present the results of the numerical simulation of experiment using by the hot water injection. In this calculation, FEHM (Finite Element Heat and Mass transfer) code is used. This code is developed at Los Alamos National Laboratory. In this experiment, temperature, pressure and cumulative gas production were measured. From these data, we suppose that MH growth/dissociation occurred by the flow of the hot water. And we make the model of the growth/dissociation. As this model consist of many parameters, it is difficult to determine parameters. Thus, we use PEST (Parameter ESTimation ) in order to determine parameters for the model of the MH growth/ dissociation. We use temperature data of experiment, as observed data. We make two observed data sets at the beginning and later term of experiment. At the results of PEST, we obtain two sets of parameters to get good match the observed data. We think that these sets indicate both the maximum and the minimum values of the MH growth/dissociation model. And, on this range, we continue to calculate until we get the good match. Finally, we obtain the numerical model of the experiment. Also, we conducted the sensitive analysis for the MH growth/ dissociation using this model.
Comparison of numerical simulations to experiments for atomization in a jet nebulizer.
Lelong, Nicolas; Vecellio, Laurent; Sommer de Gélicourt, Yann; Tanguy, Christian; Diot, Patrice; Junqua-Moullet, Alexandra
2013-01-01
The development of jet nebulizers for medical purposes is an important challenge of aerosol therapy. The performance of a nebulizer is characterized by its output rate of droplets with a diameter under 5 µm. However the optimization of this parameter through experiments has reached a plateau. The purpose of this study is to design a numerical model simulating the nebulization process and to compare it with experimental data. Such a model could provide a better understanding of the atomization process and the parameters influencing the nebulizer output. A model based on the Updraft nebulizer (Hudson) was designed with ANSYS Workbench. Boundary conditions were set with experimental data then transient 3D calculations were run on a 4 µm mesh with ANSYS Fluent. Two air flow rate (2 L/min and 8 L/min, limits of the operating range) were considered to account for different turbulence regimes. Numerical and experimental results were compared according to phenomenology and droplet size. The behavior of the liquid was compared to images acquired through shadowgraphy with a CCD Camera. Three experimental methods, laser diffractometry, phase Doppler anemometry (PDA) and shadowgraphy were used to characterize the droplet size distributions. Camera images showed similar patterns as numerical results. Droplet sizes obtained numerically are overestimated in relation to PDA and diffractometry, which only consider spherical droplets. However, at both flow rates, size distributions extracted from numerical image processing were similar to distributions obtained from shadowgraphy image processing. The simulation then provides a good understanding and prediction of the phenomena involved in the fragmentation of droplets over 10 µm. The laws of dynamics apply to droplets down to 1 µm, so we can assume the continuity of the distribution and extrapolate the results for droplets between 1 and 10 µm. So, this model could help predicting nebulizer output with defined geometrical and
Comparison of numerical simulations to experiments for atomization in a jet nebulizer.
Directory of Open Access Journals (Sweden)
Nicolas Lelong
Full Text Available The development of jet nebulizers for medical purposes is an important challenge of aerosol therapy. The performance of a nebulizer is characterized by its output rate of droplets with a diameter under 5 µm. However the optimization of this parameter through experiments has reached a plateau. The purpose of this study is to design a numerical model simulating the nebulization process and to compare it with experimental data. Such a model could provide a better understanding of the atomization process and the parameters influencing the nebulizer output. A model based on the Updraft nebulizer (Hudson was designed with ANSYS Workbench. Boundary conditions were set with experimental data then transient 3D calculations were run on a 4 µm mesh with ANSYS Fluent. Two air flow rate (2 L/min and 8 L/min, limits of the operating range were considered to account for different turbulence regimes. Numerical and experimental results were compared according to phenomenology and droplet size. The behavior of the liquid was compared to images acquired through shadowgraphy with a CCD Camera. Three experimental methods, laser diffractometry, phase Doppler anemometry (PDA and shadowgraphy were used to characterize the droplet size distributions. Camera images showed similar patterns as numerical results. Droplet sizes obtained numerically are overestimated in relation to PDA and diffractometry, which only consider spherical droplets. However, at both flow rates, size distributions extracted from numerical image processing were similar to distributions obtained from shadowgraphy image processing. The simulation then provides a good understanding and prediction of the phenomena involved in the fragmentation of droplets over 10 µm. The laws of dynamics apply to droplets down to 1 µm, so we can assume the continuity of the distribution and extrapolate the results for droplets between 1 and 10 µm. So, this model could help predicting nebulizer output with defined
International Nuclear Information System (INIS)
Glouannec, Patrick; Michel, Benoit; Delamarre, Guillaume; Grohens, Yves
2014-01-01
This paper presents an experimental and numerical design study of an insulation wall for refrigerated vans. The thermophysical properties of the insulating multilayer panel, the external environment impact (solar irradiation, temperature, etc.) and durability are taken into account. Different tools are used to characterize the thermal performances of the insulation walls and the thermal properties of the insulation materials are measured. In addition, an experiment at the wall scale is carried out and a 2D FEM model of heat and mass transfer within the wall is formulated. Three configurations are studied with this design approach. Multilayer insulation walls containing reflective multi-foil insulation, aerogel and phase change materials (PCM) are tested. Promising results are obtained with these materials, especially the reduction of peak heat transfer and energy consumption during the daytime period. Furthermore, the major influence of solar irradiation is highlighted as it can increase the peak heat transfer crossing the insulation wall by up to 43%. Nevertheless, we showed that the use of reflective multi-foil insulation and aerogel layers allowed decreasing this impact by 27%. - Highlights: • A design study of an insulation wall for a refrigerated van is carried out. • Experimental and numerical studies of multilayer insulation walls are performed. • The major influence of solar irradiation is highlighted. • New insulation materials (reflective multi-foil, aerogel and PCM) are tested
"Physically-based" numerical experiment to determine the dominant hillslope processes during floods?
Gaume, Eric; Esclaffer, Thomas; Dangla, Patrick; Payrastre, Olivier
2016-04-01
To study the dynamics of hillslope responses during flood event, a fully coupled "physically-based" model for the combined numerical simulation of surface runoff and underground flows has been developed. A particular attention has been given to the selection of appropriate numerical schemes for the modelling of both processes and of their coupling. Surprisingly, the most difficult question to solve, from a numerical point of view, was not related to the coupling of two processes with contrasted kinetics such as surface and underground flows, but to the high gradient infiltration fronts appearing in soils, source of numerical diffusion, instabilities and sometimes divergence. The model being elaborated, it has been successfully tested against results of high quality experiments conducted on a laboratory sandy slope in the early eighties, which is still considered as a reference hillslope experimental setting (Abdul & Guilham). The model appeared able to accurately simulate the pore pressure distributions observed in this 1.5 meter deep and wide laboratory hillslope, as well as its outflow hydrograph shapes and the measured respective contributions of direct runoff and groundwater to these outflow hydrographs. Based on this great success, the same model has been used to simulate the response of a theoretical 100-meter wide and 10% sloped hillslope, with a 2 meter deep pervious soil and impervious bedrock. Three rain events have been tested: a 100 millimeter rainfall event over 10 days, over 1 day or over one hour. The simulated responses are hydrologically not realistic and especially the fast component of the response, that is generally observed in the real-world and explains flood events, is almost absent of the simulated response. Thinking a little about the whole problem, the simulation results appears totally logical according to the proposed model. The simulated response, in fact a recession hydrograph, corresponds to a piston flow of a relatively uniformly
Dossmann, Yvan; Paci, Alexandre; Auclair, Francis; Floor, Jochem
2010-05-01
Internal tides are suggested to play a major role in the sustaining of the global oceanic circulation [1][5]. Although the exact origin of the energy conversions occurring in stratified fluids is questioned [2], it is clear that the diapycnal energy transfers provided by the energy cascade of internal gravity waves generated at tidal frequencies in regions of steep bathymetry is strongly linked to the general circulation energy balance. Therefore a precise quantification of the energy supply by internal waves is a crucial step in forecasting climate, since it improves our understanding of the underlying physical processes. We focus on an academic case of internal waves generated over an oceanic ridge in a linearly stratified fluid. In order to accurately quantify the diapycnal energy transfers caused by internal waves dynamics, we adopt a complementary approach involving both laboratory and numerical experiments. The laboratory experiments are conducted in a 4m long tank of the CNRM-GAME fluid mechanics laboratory, well known for its large stratified water flume (e.g. Knigge et al [3]). The horizontal oscillation at precisely controlled frequency of a Gaussian ridge immersed in a linearly stratified fluid generates internal gravity waves. The ridge of e-folding width 3.6 cm is 10 cm high and spans 50 cm. We use PIV and Synthetic Schlieren measurement techniques, to retrieve the high resolution velocity and stratification anomaly fields in the 2D vertical plane across the ridge. These experiments allow us to get access to real and exhaustive measurements of a wide range of internal waves regimes by varying the precisely controlled experimental parameters. To complete this work, we carry out some direct numerical simulations with the same parameters (forcing amplitude and frequency, initial stratification, boundary conditions) as the laboratory experiments. The model used is a non-hydrostatic version of the numerical model Symphonie [4]. Our purpose is not only to
Vriend, Nathalie; Tsang, Jonny; Arran, Matthew; Jin, Binbin; Johnsen, Alexander
2017-11-01
When a mixture of small, smooth particles and larger, coarse particles is released on a rough inclined plane, the initial uniform front may break up in distinct fingers which elongate over time. This fingering instability is sensitive to the unique arrangement of individual particles and is driven by granular segregation (Pouliquen et al., 1997). Variability in initial conditions create significant limitations for consistent experimental and numerical validation of newly developed theoretical models (Baker et al., 2016) for finger formation. We present an experimental study using a novel tool that sets the initial fingering width of the instability. By changing this trigger width between experiments, we explore the response of the avalanche breakup to perturbations of different widths. Discrete particle simulations (using MercuryDPM, Thornton et al., 2012) are conducted under a similar setting, reproducing the variable finger width, allowing validation between experiments and numerical simulations. A good agreement between simulations and experiments is obtained, and ongoing theoretical work is briefly introduced. NMV acknowledges the Royal Society Dorothy Hodgkin Research Fellowship.
Experiments and numerical simulations of fluctuating thermal stratification in a branch pipe
Energy Technology Data Exchange (ETDEWEB)
Nakamura, Akira; Murase, Michio; Sasaki, Toru [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan); Takenaka, Nobuyuki; Hamatani, Daisuke [Kobe Univ. (Japan)
2002-09-01
Many pipes branch off from the main pipe in plants. When the main flow in the main pipe is hotter than a branch pipe that branches off downward, the hot water penetrates into the branch pipe with the cavity flow that is induced by the main flow and causes thermal stratification. If the interface of the stratification fluctuates in an occluded branch pipe, thermal fatigue may occur in pipe wall. Some experiments and numerical simulations were conducted to elucidate the mechanism of this fluctuating thermal stratification. The vortex structures were observed in the experiments of straight or bent branch pipes. When the main flow was heated and the thermal stratification interface was at the elbow, a ''burst'' phenomenon occurred in the interface in connection with large heat fluctuation. The effects of pipe shape on the length of penetration were investigated in order to modify simulation conditions. The vortex structures and the fluctuating thermal stratification at elbow in the numerical simulation showed good agreement with experiments. (author)
New method of processing heat treatment experiments with numerical simulation support
Kik, T.; Moravec, J.; Novakova, I.
2017-08-01
In this work, benefits of combining modern software for numerical simulations of welding processes with laboratory research was described. Proposed new method of processing heat treatment experiments leading to obtaining relevant input data for numerical simulations of heat treatment of large parts was presented. It is now possible, by using experiments on small tested samples, to simulate cooling conditions comparable with cooling of bigger parts. Results from this method of testing makes current boundary conditions during real cooling process more accurate, but also can be used for improvement of software databases and optimization of a computational models. The point is to precise the computation of temperature fields for large scale hardening parts based on new method of temperature dependence determination of the heat transfer coefficient into hardening media for the particular material, defined maximal thickness of processed part and cooling conditions. In the paper we will also present an example of the comparison standard and modified (according to newly suggested methodology) heat transfer coefficient data’s and theirs influence on the simulation results. It shows how even the small changes influence mainly on distribution of temperature, metallurgical phases, hardness and stresses distribution. By this experiment it is also possible to obtain not only input data and data enabling optimization of computational model but at the same time also verification data. The greatest advantage of described method is independence of used cooling media type.
Penenko, Vladimir; Tsvetova, Elena; Penenko, Alexey
2015-04-01
The proposed method is considered on an example of hydrothermodynamics and atmospheric chemistry models [1,2]. In the development of the existing methods for constructing numerical schemes possessing the properties of total approximation for operators of multiscale process models, we have developed a new variational technique, which uses the concept of adjoint integrating factors. The technique is as follows. First, a basic functional of the variational principle (the integral identity that unites the model equations, initial and boundary conditions) is transformed using Lagrange's identity and the second Green's formula. As a result, the action of the operators of main problem in the space of state functions is transferred to the adjoint operators defined in the space of sufficiently smooth adjoint functions. By the choice of adjoint functions the order of the derivatives becomes lower by one than those in the original equations. We obtain a set of new balance relationships that take into account the sources and boundary conditions. Next, we introduce the decomposition of the model domain into a set of finite volumes. For multi-dimensional non-stationary problems, this technique is applied in the framework of the variational principle and schemes of decomposition and splitting on the set of physical processes for each coordinate directions successively at each time step. For each direction within the finite volume, the analytical solutions of one-dimensional homogeneous adjoint equations are constructed. In this case, the solutions of adjoint equations serve as integrating factors. The results are the hybrid discrete-analytical schemes. They have the properties of stability, approximation and unconditional monotony for convection-diffusion operators. These schemes are discrete in time and analytic in the spatial variables. They are exact in case of piecewise-constant coefficients within the finite volume and along the coordinate lines of the grid area in each
BDI: the Cadarache data bank for LMBFR integral experiment data
International Nuclear Information System (INIS)
Rimpault, G.; Reynaud, G.
1986-09-01
The Integral Data Bank is part of the procedure to create the so-called neutronic formulaire with which every design calculation is performed with associated uncertainty. A modern way to store the integral data has been set up in order to handle and recalculate easily with a standard procedure (fig. 1) each experimental programme. A direct access way to read the data allows an automatic way to obtain the calculation/experiment discrepancies associated with a particular data base. The BDI has proved to be fully operational and has been used with the new nuclear data file JEF1. In the present version of the BDI more than 140 experiments (critical mass, spectrum indexes, buckling, etc...) both from MASURCA and SNEAK critical experiments are documented and stored in an easy-to-retrieve from. Also included are irradiation experiments in PHENIX and the STEK fission product related experiments. Future plans of development concern reactivity measurements in critical assemblies, irradiation experiments and start-up experiments of SUPER PHENIX and ZEBRA critical experiments
Groundwater flow through a natural fracture. Flow experiments and numerical modelling
Energy Technology Data Exchange (ETDEWEB)
Larsson, Erik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept of Geology
1997-09-01
Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes. 25 refs, 17 tabs, 43 figs.
Groundwater flow through a natural fracture. Flow experiments and numerical modelling
International Nuclear Information System (INIS)
Larsson, Erik
1997-09-01
Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes
Energy Technology Data Exchange (ETDEWEB)
Koss, K. G.; Petrov, O. F.; Myasnikov, M. I., E-mail: miasnikovmi@mail.ru; Statsenko, K. B.; Vasiliev, M. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
2016-07-15
The results of experimental and numerical analysis are presented for phase transitions in strongly nonequilibrium small systems of strongly interacting Brownian particles. The dynamic entropy method is applied to analysis of the state of these systems. Experiments are carried out with kinetic heating of the structures of micron-size particles in a laboratory rf discharge plasma. Three phase states of these small systems are observed: crystalline, liquid, and transient. The mechanism of phase transitions in cluster structures of strongly interacting particles is described.
Influence of strain gradients on lattice rotation in nano-indentation experiments: A numerical study
Demiral, Murat
2014-07-01
In this paper the texture evolution in nano-indentation experiments was investigated numerically. To achieve this, a three-dimensional implicit finite-element model incorporating a strain-gradient crystal-plasticity theory was developed to represent accurately the deformation of a body-centred cubic metallic material. A hardening model was implemented to account for strain hardening of the involved slip systems. The surface topography around indents in different crystallographic orientations was compared to corresponding lattice rotations. The influence of strain gradients on the prediction of lattice rotations in nano-indentation was critically assessed. © 2014 Elsevier B.V..
Short-crested waves in deep water: a numerical investigation of recent laboratory experiments
DEFF Research Database (Denmark)
Fuhrman, David R.; Madsen, Per A.
2006-01-01
A numerical study of quasi-steady, doubly-periodic monochromatic short-crested wave patterns in deep water is conducted using a high-order Boussinesq-type model. Simulations using linear wavemaker conditions in the nonlinear model are initially used to approximate conditions from recent laboratory...... experiments. The computed patterns share many features with those observed in wavetanks, including bending (both frontwards and backwards) of the wave crests, dipping at the crest centerlines, and a pronounced long modulation in the direction of propagation. A new and simple explanation for these features...
International Nuclear Information System (INIS)
Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai
2012-01-01
Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.
Influence of strain gradients on lattice rotation in nano-indentation experiments: A numerical study
Demiral, Murat; Roy, Anish; El Sayed, Tamer S.; Silberschmidt, Vadim V.
2014-01-01
In this paper the texture evolution in nano-indentation experiments was investigated numerically. To achieve this, a three-dimensional implicit finite-element model incorporating a strain-gradient crystal-plasticity theory was developed to represent accurately the deformation of a body-centred cubic metallic material. A hardening model was implemented to account for strain hardening of the involved slip systems. The surface topography around indents in different crystallographic orientations was compared to corresponding lattice rotations. The influence of strain gradients on the prediction of lattice rotations in nano-indentation was critically assessed. © 2014 Elsevier B.V..
Tablets in K-12 Education: Integrated Experiences and Implications
An, Heejung, Ed.; Alon, Sandra, Ed.; Fuentes, David, Ed.
2015-01-01
The inclusion of new and emerging technologies in the education sector has been a topic of interest to researchers, educators, and software developers alike in recent years. Utilizing the proper tools in a classroom setting is a critical factor in student success. "Tablets in K-12 Education: Integrated Experiences and Implications"…
Comment for nuclear data from the FNS integral experiments
International Nuclear Information System (INIS)
Maekawa, Hiroshi
1983-01-01
Among the integral experiments that were carried out during last one year at FNS, the following three experimental results and their analyses are discribed. 1) Tritium production-rate distribution in a Li 2 O-C assembly, 2) Angle dependent neutron leakage spectra from Li 2 O slab assemblies, 3) Induced activity of Type 316 stainless steel. (author)
Teaching with Videogames: How Experience Impacts Classroom Integration
Bell, Amanda; Gresalfi, Melissa
2017-01-01
Digital games have demonstrated great potential for supporting students' learning across disciplines. But integrating games into instruction is challenging and requires teachers to shift instructional practices. One factor that contributes to the successful use of games in a classroom is teachers' experience implementing the technologies. But how…
International Students' Experiences of Integrating into the Workforce
Nunes, Sarah; Arthur, Nancy
2013-01-01
This study explored the integration experiences of 16 international students entering the Canadian workforce using a semistructured interview and constant comparison method. The international students were pursuing immigration to Canada, despite unmet job prospects. Students recommended that employers refrain from discriminating against students…
Colleges' Experiences: Integrating Support Services for Military Veterans
Karp, Melinda Mechur; Klempin, Serena
2017-01-01
To improve the educational experiences and outcomes of student veterans, the Kisco Foundation developed the Kohlberg Prize in 2015. Two cohorts of colleges were awarded competitive grants to enhance their veterans services. This piece examines the process of creating integrated services for student veterans through the institutionalization of…
Numerical Simulation Applications in the Design of EGS Collab Experiment 1
Energy Technology Data Exchange (ETDEWEB)
Johnston, Henry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); White, Mark D. [Pacific Northwest National Laboratory; Fu, Pengcheng [Lawrence Livermore National Laboratory; Ghassemi, Ahmad [University of Oklahoma; Huang, Hai [Idaho National Laboratory; Rutqvist, Jonny [Lawrence Berkeley National Laboratory
2018-02-14
The United States Department of Energy, Geothermal Technologies Office (GTO) is funding a collaborative investigation of enhanced geothermal systems (EGS) processes at the meso-scale. This study, referred to as the EGS Collab project, is a unique opportunity for scientists and engineers to investigate the creation of fracture networks and circulation of fluids across those networks under in-situ stress conditions. The EGS Collab project is envisioned to comprise three experiments and the site for the first experiment is on the 4850 Level (4,850 feet below ground surface) in phyllite of the Precambrian Poorman formation, at the Sanford Underground Research Facility, located at the former Homestake Gold Mine, in Lead, South Dakota. Principal objectives of the project are to develop a number of intermediate-scale field sites and to conduct well-controlled in situ experiments focused on rock fracture behavior and permeability enhancement. Data generated during these experiments will be compared against predictions of a suite of computer codes specifically designed to solve problems involving coupled thermal, hydrological, geomechanical, and geochemical processes. Comparisons between experimental and numerical simulation results will provide code developers with direction for improvements and verification of process models, build confidence in the suite of available numerical tools, and ultimately identify critical future development needs for the geothermal modeling community. Moreover, conducting thorough comparisons of models, modelling approaches, measurement approaches and measured data, via the EGS Collab project, will serve to identify techniques that are most likely to succeed at the Frontier Observatory for Research in Geothermal Energy (FORGE), the GTO's flagship EGS research effort. As noted, outcomes from the EGS Collab project experiments will serve as benchmarks for computer code verification, but numerical simulation additionally plays an essential
Experiences of technology integration in home care nursing.
Johnson, K A; Valdez, R S; Casper, G R; Kossman, S P; Carayon, P; Or, C K L; Burke, L J; Brennan, P F
2008-11-06
The infusion of health care technologies into the home leads to substantial changes in the nature of work for home care nurses and their patients. Nurses and nursing practice must change to capitalize on these innovations. As part of a randomized field experiment evaluating web-based support for home care of patients with chronic heart disease, we engaged nine nurses in a dialogue about their experience integrating this modification of care delivery into their practice. They shared their perceptions of the work they needed to do and their perceptions and expectations for patients and themselves in using technologies to promote and manage self-care. We document three overarching themes that identify preexisting factors that influenced integration or represent the consequences of technology integration into home care: doing tasks differently, making accommodations in the home for devices and computers, and being mindful of existing expectations and skills of both nurses and patients.
DEFF Research Database (Denmark)
Elarga, Hagar; Fantucci, Stefano; Serra, Valentina
2017-01-01
portions, one, the bare roof, representing the reference case without PCMs, the other two integrating two PCM's typologies with different melting/solidification temperatures range. A numerical model was furthermore developed implementing the equivalent capacitance numerical method to describe the substance...... peak load between 13% and 59% depending on the PCM typology, highlighting that to reach the expected performance the proper PCM type should be carefully selected....
Phase Change Materials-Assisted Heat Flux Reduction: Experiment and Numerical Analysis
Directory of Open Access Journals (Sweden)
Hussein J. Akeiber
2016-01-01
Full Text Available Phase change materials (PCM in the construction industry became attractive because of several interesting attributes, such as thermo-physical parameters, open air atmospheric condition usage, cost and the duty structure requirement. Thermal performance optimization of PCMs in terms of proficient storage of a large amount of heat or cold in a finite volume remains a challenging task. Implementation of PCMs in buildings to achieve thermal comfort for a specific climatic condition in Iraq is our main focus. From this standpoint, the present paper reports the experimental and numerical results on the lowering of heat flux inside a residential building using PCM, which is composed of oil (40% and wax (60%. This PCM (paraffin, being plentiful and cost-effective, is extracted locally from waste petroleum products in Iraq. Experiments are performed with two rooms of identical internal dimensions in the presence and absence of PCM. A two-dimensional numerical transient heat transfer model is developed and solved using the finite difference method. A relatively simple geometry is chosen to initially verify the numerical solution procedure by incorporating in the computer program two-dimensional elliptic flows. It is demonstrated that the heat flux inside the room containing PCM is remarkably lower than the one devoid of PCM.
Numerical simulation and experiment of high-intensity current pulsed impact on the structure body
International Nuclear Information System (INIS)
Li Mintang; Yan Ping; Yuan Weiqun; Sun Yaohong; Sun Lianhua; Zhou Yuan; Liu Chuanpu
2010-01-01
To better understand the characteristics of the impulse force formed by pulse current of electromagnetic rail propulsion system, and to explore effective ways to improve the support structure of rails, a set of impulse force test system was designed, and the work-related test situation was numerically simulated. Several impulse force waveforms formed by different pulse current waveforms were achieved by using an armature as a source of impulse force in this test system, and two curves of waveform were comparatively analyzed. The armature existing in the environment of coupling fields including electric field and magnetic field and force field was carried out numerical calculation by using the software of ANSYS, and the coupling force field was emphatically analyzed to calculate the electromagnetic driving force and the electromagnetic clamping force acting on the armature, and the structure stress and deformation was also analyzed. The results showed that the curves of electromagnetic driving force computed by numerical simulation and the curves of impulse force obtained by experiment were basically the same, and the value of peak points' error was increasing along with the increase of pulse current, but the curves still showed some common characteristics. This verified that the test method we used in this paper was proper to capture the impulse force, and the method of calculation was also feasible and effective. (authors)
International Nuclear Information System (INIS)
Storch, H. von; Schriever, D.; Arpe, K.; Branstator, G.W.; Legnani, R.; Ulbrich, U.
1993-01-01
The effect of cold conditions in the central and eastern Equatorial Pacific during Northern Summer is examined in a series of numerical experiments with the low resolution (T21) atmospheric general circulation model ECHAM2. Anomalous sea surface temperatures (SST) as observed in June 1988 were prescribed and the effect on the global circulation is examined. In the model atmosphere, the anomalous cold water in the Equatorial Pacific excites a strong and stable response over the tropical Central and East Pacific. From here stationary Rossby waves radiate into both hemispheres. The Northern Hemisphere wave train is weak and affects only the Northeast Pacific area; the Southern Hemisphere wave train arches from the Central Pacific over the southern tip of South America to the South Atlantic. This response is not only present in the basic anomaly experiment with the T21 GCM but also in experiments with SST anomalies confined to the tropics and with an envelope-formulation of the SST anomalies, in experiments with a linear model, and in high resolution (T42) model experiments. The model output is also compared to the actually observed atmospheric state in June 1988. (orig./KW)
Miyoshi, S; Sakajiri, M; Ifukube, T; Matsushima, J
1997-01-01
We have proposed the Tripolar Electrode Stimulation Method (TESM) which may enable us to narrow the stimulation region and to move continuously the stimulation site for the cochlear implants. We evaluated whether or not TESM works according to a theory based on numerical analysis using the auditory nerve fiber model. In this simulation, the sum of the excited model fibers were compared with the compound actions potentials obtained from animal experiments. As a result, this experiment showed that TESM could narrow a stimulation region by controlling the sum of the currents emitted from the electrodes on both sides, and continuously move a stimulation site by changing the ratio of the currents emitted from the electrodes on both sides.
Lamb, M.; Toniolo, H.; Parker, G.
2001-12-01
The slope of the continental margin of the northern Gulf of Mexico is riddled with small basins resulting from salt tectonics. Each such minibasin is the result of local subsidence due to salt withdrawal, and is isolated from neighboring basins by ridges formed due to compensational uplift. The minibasins are gradually filled by turbidity currents, which are active at low sea stand. Experiments in a 1-D minibasin reveal that a turbidity current flowing into a deep minibasin must undergo a hydraulic jump and form a muddy pond. This pond may not spill out of the basin even with continuous inflow. The reason for this is the detrainment of water across the settling interface that forms at the top of the muddy pond. Results of both experiments and numerical modeling of the flow and the evolution of the deposit are presented. The numerical model is the first of its kind to capture both the hydraulic jump and the effect of detrainment in ponded turbidity currents.
International Nuclear Information System (INIS)
Hyung, Jin Shim; Beom, Seok Han; Chang, Hyo Kim
2003-01-01
Monte Carlo (MC) power method based on the fixed number of fission sites at the beginning of each cycle is known to cause biases in the variances of the k-eigenvalue (keff) and the fission reaction rate estimates. Because of the biases, the apparent variances of keff and the fission reaction rate estimates from a single MC run tend to be smaller or larger than the real variances of the corresponding quantities, depending on the degree of the inter-generational correlation of the sample. We demonstrate this through a numerical experiment involving 100 independent MC runs for the neutronics analysis of a 17 x 17 fuel assembly of a pressurized water reactor (PWR). We also demonstrate through the numerical experiment that Gelbard and Prael's batch method and Ueki et al's covariance estimation method enable one to estimate the approximate real variances of keff and the fission reaction rate estimates from a single MC run. We then show that the use of the approximate real variances from the two-bias predicting methods instead of the apparent variances provides an efficient MC power iteration scheme that is required in the MC neutronics analysis of a real system to determine the pin power distribution consistent with the thermal hydraulic (TH) conditions of individual pins of the system. (authors)
Local mechanical properties of LFT injection molded parts: Numerical simulations versus experiments
Desplentere, F.; Soete, K.; Bonte, H.; Debrabandere, E.
2014-05-01
In predictive engineering for polymer processes, the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT, length Autodesk Simulation Moldflow Insight 2014 software has been used. In this software, a fiber breakage algorithm for the polymer flow inside the mold is available. Using well known micro mechanic formulas allow to combine the local fiber length with the local orientation into local mechanical properties. Different experiments were performed using a commercially available glass fiber filled compound to compare the measured data with the numerical simulation results. In this investigation, tensile tests and 3 point bending tests are considered. To characterize the fiber length distribution of the polymer melt entering the mold (necessary for the numerical simulations), air shots were performed. For those air shots, similar homogenization conditions were used as during the injection molding tests. The fiber length distribution is characterized using automated optical method on samples for which the matrix material is burned away. Using the appropriate settings for the different experiments, good predictions of the local mechanical properties are obtained.
International Nuclear Information System (INIS)
Chen, Xiangyi; Suh, Kune Y.
2016-01-01
In this work, this benchmark problem is conducted to assess the precision of the upgraded in-house code MINA. Comparison of the results from different best estimate codes employed by various grid spacer pressure drop correlations is carried out to suggest the best one. By modifying In's method, it presents good agreement with the experiment data which is shown in Figure 7. The reason for the failure of the prediction in previous work is caused by the utilization of Rehme's method which is categorized into four groups according to different fitting strategy. Through comparison of drag coefficients calculated by four groups of Rheme's method, equivalent drag coefficient calculated by In's method and experiment data shown in Figure 8, we can conclude that Rehme's method considerably underestimate the drag coefficients in grid spacers used in HELIOS and In's method give a reasonable prediction. Starting from the core inlet, the accumulated pressure losses are presented in figure 9 along the accumulated length of the forced convection flow path; the good agreement of the prediction from MINA with the experiment result shows MINA has very good capability in integrated momentum analysis makes it robust in the future design scoping method development of LFR.
Energy Technology Data Exchange (ETDEWEB)
Chen, Xiangyi; Suh, Kune Y. [KAERI, Daejeon (Korea, Republic of)
2016-05-15
In this work, this benchmark problem is conducted to assess the precision of the upgraded in-house code MINA. Comparison of the results from different best estimate codes employed by various grid spacer pressure drop correlations is carried out to suggest the best one. By modifying In's method, it presents good agreement with the experiment data which is shown in Figure 7. The reason for the failure of the prediction in previous work is caused by the utilization of Rehme's method which is categorized into four groups according to different fitting strategy. Through comparison of drag coefficients calculated by four groups of Rheme's method, equivalent drag coefficient calculated by In's method and experiment data shown in Figure 8, we can conclude that Rehme's method considerably underestimate the drag coefficients in grid spacers used in HELIOS and In's method give a reasonable prediction. Starting from the core inlet, the accumulated pressure losses are presented in figure 9 along the accumulated length of the forced convection flow path; the good agreement of the prediction from MINA with the experiment result shows MINA has very good capability in integrated momentum analysis makes it robust in the future design scoping method development of LFR.
Directory of Open Access Journals (Sweden)
Saraswathi Ananthavel
2016-06-01
Full Text Available Power system researches are mainly focused in enhancing the available power capacities of the existing transmission lines. But still, no prominent solutions have been made due to several factors that affect the transmission lines which include the length, aging of the cables and losses on generation, transmission and distribution etc. This paper exploited the integration of static synchronous compensator (STATCOM and superconducting magnetic energy storage (SMES which is then connected to existing power transmission line for enhancing the available power transfer capacity (ATC. STATCOM is power electronic voltage source converter (VSC which is connected to the transmission system for shunt reactive power and harmonics compensation. SMES is a renowned clean energy storage technology. Feasibility of the proposed power system can control the real as well as reactive power flow independently between the transmission lines and STATCOM-(SMES units. Complete proposed power system is implemented in numerical simulation software (Matlab/Simulink and its performance is validated based on obtained investigation results.
Li, Wei; Zhang, Min; Wang, Mingyu; Han, Zhantao; Liu, Jiankai; Chen, Zhezhou; Liu, Bo; Yan, Yan; Liu, Zhu
2018-06-01
Brownfield sites pollution and remediation is an urgent environmental issue worldwide. The screening and assessment of remedial alternatives is especially complex owing to its multiple criteria that involves technique, economy, and policy. To help the decision-makers selecting the remedial alternatives efficiently, the criteria framework conducted by the U.S. EPA is improved and a comprehensive method that integrates multiple criteria decision analysis (MCDA) with numerical simulation is conducted in this paper. The criteria framework is modified and classified into three categories: qualitative, semi-quantitative, and quantitative criteria, MCDA method, AHP-PROMETHEE (analytical hierarchy process-preference ranking organization method for enrichment evaluation) is used to determine the priority ranking of the remedial alternatives and the solute transport simulation is conducted to assess the remedial efficiency. A case study was present to demonstrate the screening method in a brownfield site in Cangzhou, northern China. The results show that the systematic method provides a reliable way to quantify the priority of the remedial alternatives.
Boundary integral equation methods and numerical solutions thin plates on an elastic foundation
Constanda, Christian; Hamill, William
2016-01-01
This book presents and explains a general, efficient, and elegant method for solving the Dirichlet, Neumann, and Robin boundary value problems for the extensional deformation of a thin plate on an elastic foundation. The solutions of these problems are obtained both analytically—by means of direct and indirect boundary integral equation methods (BIEMs)—and numerically, through the application of a boundary element technique. The text discusses the methodology for constructing a BIEM, deriving all the attending mathematical properties with full rigor. The model investigated in the book can serve as a template for the study of any linear elliptic two-dimensional problem with constant coefficients. The representation of the solution in terms of single-layer and double-layer potentials is pivotal in the development of a BIEM, which, in turn, forms the basis for the second part of the book, where approximate solutions are computed with a high degree of accuracy. The book is intended for graduate students and r...
An Integrated Numerical Model for the Design of Coastal Protection Structures
Directory of Open Access Journals (Sweden)
Theophanis V. Karambas
2017-10-01
Full Text Available In the present work, an integrated coastal engineering numerical model is presented. The model simulates the linear wave propagation, wave-induced circulation, and sediment transport and bed morphology evolution. It consists of three main modules: WAVE_L, WICIR, and SEDTR. The nearshore wave transformation module WAVE_L (WAVE_Linear is based on the hyperbolic-type mild slope equation and is valid for a compound linear wave field near coastal structures where the waves are subjected to the combined effects of shoaling, refraction, diffraction, reflection (total and partial, and breaking. Radiation stress components (calculated from WAVE_L drive the depth averaged circulation module WICIR (Wave Induced CIRculation for the description of the nearshore wave-induced currents. Sediment transport and bed morphology evolution in the nearshore, surf, and swash zone are simulated by the SEDTR (SEDiment TRansport module. The model is tested against experimental data to study the effect of representative coastal protection structures and is applied to a real case study of a coastal engineering project in North Greece, producing accurate and consistent results for a versatile range of layouts.
Trends in integrated circuit design for particle physics experiments
International Nuclear Information System (INIS)
Atkin, E V
2017-01-01
Integrated circuits are one of the key complex units available to designers of multichannel detector setups. A whole number of factors makes Application Specific Integrated Circuits (ASICs) valuable for Particle Physics and Astrophysics experiments. Among them the most important ones are: integration scale, low power dissipation, radiation tolerance. In order to make possible future experiments in the intensity, cosmic, and energy frontiers today ASICs should provide new level of functionality at a new set of constraints and trade-offs, like low-noise high-dynamic range amplification and pulse shaping, high-speed waveform sampling, low power digitization, fast digital data processing, serialization and data transmission. All integrated circuits, necessary for physical instrumentation, should be radiation tolerant at an earlier not reached level (hundreds of Mrad) of total ionizing dose and allow minute almost 3D assemblies. The paper is based on literary source analysis and presents an overview of the state of the art and trends in nowadays chip design, using partially own ASIC lab experience. That shows a next stage of ising micro- and nanoelectronics in physical instrumentation. (paper)
Experience Supporting the Integration of LHC Experiments Software Framework with the LCG Middleware
Santinelli, Roberto
2006-01-01
The LHC experiments are currently preparing for data acquisition in 2007 and because of the large amount of required computing and storage resources, they decided to embrace the grid paradigm. The LHC Computing Project (LCG) provides and operates a computing infrastructure suitable for data handling, Monte Carlo production and analysis. While LCG offers a set of high level services, intended to be generic enough to accommodate the needs of different Virtual Organizations, the LHC experiments software framework and applications are very specific and focused on the computing and data models. The LCG Experiment Integration Support team works in close contact with the experiments, the middleware developers and the LCG certification and operations teams to integrate the underlying grid middleware with the experiment specific components. The strategical position between the experiments and the middleware suppliers allows EIS team to play a key role at communications level between the customers and the service provi...
International Nuclear Information System (INIS)
Noguchi, M.; Takeda, K.; Higuchi, H.
1981-01-01
A method of γ-ray efficiency determination for extended (plane or bulk) samples based on numerical integration of point source efficiency is studied. The proposed method is widely applicable to samples of various shapes and materials. The geometrical factor in the peak efficiency can easily be corrected for by simply changing the integration region, and γ-ray self-absorption is also corrected by the absorption coefficients for the sample matrix. (author)
International Nuclear Information System (INIS)
Lobanov, Yu.Yu.; Shahbagian, R.R.; Zhidkov, E.P.
1991-01-01
A new method for numerical solution of the boundary problem for Schroedinger-like partial differential equations in R n is elaborated. The method is based on representation of multidimensional Green function in the form of multiple functional integral and on the use of approximation formulas which are constructed for such integrals. The convergence of approximations to the exact value is proved, the remainder of the formulas is estimated. Method reduces the initial differential problem to quadratures. 16 refs.; 7 tabs
Technology choices for the Integrated Beam Experiment (IBX)
Energy Technology Data Exchange (ETDEWEB)
Leitner, M.A.; Celata, C.M.; Lee, E.P.; Sabbi, G.; Waldron, W.L.; Barnard, J.J.
2002-10-31
Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, we aim for a complete ''source-to-target'' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a single heavy ion beam at high current ({approx}1 A) through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing. This paper describes the main parameters and technology choices of the planned IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at target of more than 10 Amperes. Different accelerator cell design options are described in detail: Induction cores incorporating either room temperature pulsed focusing-magnets or superconducting magnets.
Induction Accelerator Technology Choices for the Integrated Beam Experiment (IBX)
International Nuclear Information System (INIS)
Leitner, M.A.; Celata, C.M.; Lee, E.P.; Logan, B.G.; Sabbi, G.; Waldron, W.L.; Barnard, J.J.
2003-01-01
Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, we aim for a complete 'source-to-target' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a single heavy ion beam at high current (∼1 A) through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing.This paper describes the main parameters and technology choices of the planned IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at target of more than 10 Amperes. Different accelerator cell design options are described in detail: Induction cores incorporating either room temperature pulsed focusing-magnets or superconducting magnets
A numerical study of the integral equations for the laser fields in free-electron lasers
International Nuclear Information System (INIS)
Yoo, J. G.; Park, S. H.; Jeong, Y. U.; Lee, B. C.; Rhee, Y. J.; Cho, S. O.
2004-01-01
The dynamics of the radiation fields in free-electron lasers is investigated on the basis of the integro-differential equations in the one-dimensional formulation. For simple cases we solved the integro-differential equations analytically and numerically to test our numerical procedures developed on the basis of the Filon method. The numerical results showed good agreement with the analytical solutions. To confirm the legitimacy of the numerical package, we carried out numerical studies on the inhomogeneous broadening effects, where no analytic solutions are available, due to the energy spread and the emittance of the electron beam.
A desiccant-enhanced evaporative air conditioner: Numerical model and experiments
International Nuclear Information System (INIS)
Woods, Jason; Kozubal, Eric
2013-01-01
Highlights: ► We studied a new process combining liquid desiccants and evaporative cooling. ► We modeled the process using a finite-difference numerical model. ► We measured the performance of the process with experimental prototypes. ► Results show agreement between model and experiment of ±10%. ► Results add confidence to previous modeled energy savings estimates of 40–85%. - Abstract: This article presents modeling and experimental results on a recently proposed liquid desiccant air conditioner, which consists of two stages: a liquid desiccant dehumidifier and an indirect evaporative cooler. Each stage is a stack of channel pairs, where a channel pair is a process air channel separated from an exhaust air channel with a thin plastic plate. In the first stage, a liquid desiccant film, which lines the process air channels, removes moisture from the air through a porous hydrophobic membrane. An evaporating water film wets the surface of the exhaust channels and transfers the enthalpy of vaporization from the liquid desiccant into an exhaust airstream, cooling the desiccant and enabling lower outlet humidity. The second stage is a counterflow indirect evaporative cooler that siphons off and uses a portion of the cool-dry air exiting the second stage as the evaporative sink. The objectives of this article are to (1) present fluid-thermal numerical models for each stage, (2) present experimental results of prototypes for each stage, and (3) compare the modeled and experimental results. Several experiments were performed on the prototypes over a range of inlet temperatures and humidities, process and exhaust air flow rates, and desiccant concentrations and flow rates. The model predicts the experiments within ±10%.
Kersemans, Mathias; Martens, Arvid; Van Den Abeele, Koen; Degrieck, Joris; Pyl, Lincy; Zastavnik, Filip; Sol, Hugo; Van Paepegem, Wim
2015-04-01
Conventionally, the ultrasonic polar scan (UPS) records the amplitude or time-of-flight in transmission using short ultrasonic pulses for a wide range of incidence angles, resulting in a fingerprint of the critical bulk wave angles of the material at the insonified spot. Here, we investigate the use of quasi-harmonic ultrasound (bursts) in a polar scan experiment, both experimentally and numerically. It is shown that the nature of the fingerprint drastically changes, and reveals the positions of the leaky Lamb angles. To compare with experiments, both plane wave and bounded beam simulations have been performed based on the recursive stiffness matrix method. Whereas the plane wave computations yield a pure Lamb wave angle fingerprint, this is no longer valid for the more realistic case of a bounded beam. The experimental recordings are fully supported by the bounded beam simulations. To complement the traditional amplitude measurement, experimental and numerical investigations have been performed to record, predict and analyze the phase of the transmitted ultrasonic beam. This results in the conceptual introduction of the 'phase polar scan', exposing even more intriguing and detailed patterns. In fact, the combination of the amplitude and the phase polar scan provides the complete knowledge about the complex transmission coefficient for every possible angle of incidence. This comprehensive information will be very valuable for inverse modeling of the local elasticity tensor based on a single UPS experiment. Finally, the UPS method has been applied for the detection of an artificial delamination. Compared to the pulsed UPS, the quasi-harmonic UPS (both the amplitude and phase recording) shows a superior sensitivity to the presence of a delamination. Copyright © 2015 Elsevier B.V. All rights reserved.
Bonotto, C.
1995-01-01
Attempted to verify knowledge regarding decimal and rational numbers in children ages 10-14. Discusses how pupils can receive and assimilate extensions of the number system from natural numbers to decimals and fractions and later can integrate this extension into a single and coherent numerical structure. (Author/MKR)
Banyukevich, A.; Ziolkovski, K.
1975-01-01
A number of hybrid methods for solving Cauchy problems are described on the basis of an evaluation of advantages of single and multiple-point numerical integration methods. The selection criterion is the principle of minimizing computer time. The methods discussed include the Nordsieck method, the Bulirsch-Stoer extrapolation method, and the method of recursive Taylor-Steffensen power series.
Caffo, Michele; Czyz, Henryk; Gunia, Michal; Remiddi, Ettore
2008-01-01
We present the program BOKASUN for fast and precise evaluation of the Master Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the internal masses and the external four-momentum. We use a combination of two methods: a Bernoulli accelerated series expansion and a Runge-Kutta numerical solution of a system of linear differential equations.
National Research Council Canada - National Science Library
Mitchell, Jason
2002-01-01
A method is presented for the generation of exact numerical coefficients found in two families of implicit Chebyshev methods for the numerical integration of first- and second-order ordinary differential equations...
Experience and Strategy of Biodiversity Data Integration in Taiwan
Directory of Open Access Journals (Sweden)
K T Shao
2013-02-01
Full Text Available The integration of Taiwan's biodiversity databases started in 2001, the same year that Taiwan joined GBIF as an associate participant. Taiwan, hence, embarked on a decade of integrating biodiversity data. Under the support of NSC and COA, the database and websites of TaiBIF, TaiBNET (TaiCOL, TaiBOL, and TaiEOL have been established separately and collaborate with the GBIF, COL, BOL, and EOL respectively. A cross-agency committee was thus established in Academia Sinica in 2008 to formulate policies on data collection and integration as well as the mechanism to make data available to the public. Any commissioned project will hereafter be asked to include these policy requirements in its contract. So far, TaiBIF has gained recognition in Taiwan and abroad for its efforts over the past several years. It can provide its experience and insights for others to reference or replicate.
Ring-fault activity at subsiding calderas studied from analogue experiments and numerical modeling
Liu, Y. K.; Ruch, J.; Vasyura-Bathke, H.; Jonsson, S.
2017-12-01
Several subsiding calderas, such as the ones in the Galápagos archipelago and the Axial seamount in the Pacific Ocean have shown a complex but similar ground deformation pattern, composed of a broad deflation signal affecting the entire volcanic edifice and of a localized subsidence signal focused within the caldera. However, it is still debated how deep processes at subsiding calderas, including magmatic pressure changes, source locations and ring-faulting, relate to this observed surface deformation pattern. We combine analogue sandbox experiments with numerical modeling to study processes involved from initial subsidence to later collapse of calderas. The sandbox apparatus is composed of a motor driven subsiding half-piston connected to the bottom of a glass box. During the experiments the observation is done by five digital cameras photographing from various perspectives. We use Photoscan, a photogrammetry software and PIVLab, a time-resolved digital image correlation tool, to retrieve time-series of digital elevation models and velocity fields from acquired photographs. This setup allows tracking the processes acting both at depth and at the surface, and to assess their relative importance as the subsidence evolves to a collapse. We also use the Boundary Element Method to build a numerical model of the experiment setup, which comprises contracting sill-like source in interaction with a ring-fault in elastic half-space. We then compare our results from these two approaches with the examples observed in nature. Our preliminary experimental and numerical results show that at the initial stage of magmatic withdrawal, when the ring-fault is not yet well formed, broad and smooth deflation dominates at the surface. As the withdrawal increases, narrower subsidence bowl develops accompanied by the upward propagation of the ring-faulting. This indicates that the broad deflation, affecting the entire volcano edifice, is primarily driven by the contraction of the
Cienfuegos, R.; Duarte, L.; Hernandez, E.
2008-12-01
Charasteristic frequencies of gravity waves generated by wind and propagating towards the coast are usually comprised between 0.05Hz and 1Hz. Nevertheless, lower frequecy waves, in the range of 0.001Hz and 0.05Hz, have been observed in the nearshore zone. Those long waves, termed as infragravity waves, are generated by complex nonlinear mechanisms affecting the propagation of irregular waves up to the coast. The groupiness of an incident random wave field may be responsible for producing a slow modulation of the mean water surface thus generating bound long waves travelling at the group speed. Similarly, a quasi- periodic oscillation of the break-point location, will be accompained by a slow modulation of set-up/set-down in the surf zone and generation and release of long waves. If the primary structure of the carrying incident gravity waves is destroyed (e.g. by breaking), forced long waves can be freely released and even reflected at the coast. Infragravity waves can affect port operation through resonating conditions, or strongly affect sediment transport and beach morphodynamics. In the present study we investigate infragravity wave generation mechanisms both, from experiments and numerical computations. Measurements were conducted at the 70-meter long wave tank, located at the Instituto Nacional de Hidraulica (Chile), prepared with a beach of very mild slope of 1/80 in order to produce large surf zone extensions. A random JONSWAP type wave field (h0=0.52m, fp=0.25Hz, Hmo=0.17m) was generated by a piston wave-maker and measurements of the free surface displacements were performed all over its length at high spatial resolution (0.2m to 1m). Velocity profiles were also measured at four verticals inside the surf zone using an ADV. Correlation maps of wave group envelopes and infragravity waves are computed in order to identify long wave generation and dynamics in the experimental set-up. It appears that both mechanisms (groupiness and break-point oscillation) are
International Nuclear Information System (INIS)
Azadeh, A.; Amalnick, M.S.; Ghaderi, S.F.; Asadzadeh, S.M.
2007-01-01
This paper introduces an integrated approach based on data envelopment analysis (DEA), principal component analysis (PCA) and numerical taxonomy (NT) for total energy efficiency assessment and optimization in energy intensive manufacturing sectors. Total energy efficiency assessment and optimization of the proposed approach considers structural indicators in addition conventional consumption and manufacturing sector output indicators. The validity of the DEA model is verified and validated by PCA and NT through Spearman correlation experiment. Moreover, the proposed approach uses the measure-specific super-efficiency DEA model for sensitivity analysis to determine the critical energy carriers. Four energy intensive manufacturing sectors are discussed in this paper: iron and steel, pulp and paper, petroleum refining and cement manufacturing sectors. To show superiority and applicability, the proposed approach has been applied to refinery sub-sectors of some OECD (Organization for Economic Cooperation and Development) countries. This study has several unique features which are: (1) a total approach which considers structural indicators in addition to conventional energy efficiency indicators; (2) a verification and validation mechanism for DEA by PCA and NT and (3) utilization of DEA for total energy efficiency assessment and consumption optimization of energy intensive manufacturing sectors
Integrated multiscale biomaterials experiment and modelling: a perspective
Buehler, Markus J.; Genin, Guy M.
2016-01-01
Advances in multiscale models and computational power have enabled a broad toolset to predict how molecules, cells, tissues and organs behave and develop. A key theme in biological systems is the emergence of macroscale behaviour from collective behaviours across a range of length and timescales, and a key element of these models is therefore hierarchical simulation. However, this predictive capacity has far outstripped our ability to validate predictions experimentally, particularly when multiple hierarchical levels are involved. The state of the art represents careful integration of multiscale experiment and modelling, and yields not only validation, but also insights into deformation and relaxation mechanisms across scales. We present here a sampling of key results that highlight both challenges and opportunities for integrated multiscale experiment and modelling in biological systems. PMID:28981126
Software for the Integration of Multiomics Experiments in Bioconductor.
Ramos, Marcel; Schiffer, Lucas; Re, Angela; Azhar, Rimsha; Basunia, Azfar; Rodriguez, Carmen; Chan, Tiffany; Chapman, Phil; Davis, Sean R; Gomez-Cabrero, David; Culhane, Aedin C; Haibe-Kains, Benjamin; Hansen, Kasper D; Kodali, Hanish; Louis, Marie S; Mer, Arvind S; Riester, Markus; Morgan, Martin; Carey, Vince; Waldron, Levi
2017-11-01
Multiomics experiments are increasingly commonplace in biomedical research and add layers of complexity to experimental design, data integration, and analysis. R and Bioconductor provide a generic framework for statistical analysis and visualization, as well as specialized data classes for a variety of high-throughput data types, but methods are lacking for integrative analysis of multiomics experiments. The MultiAssayExperiment software package, implemented in R and leveraging Bioconductor software and design principles, provides for the coordinated representation of, storage of, and operation on multiple diverse genomics data. We provide the unrestricted multiple 'omics data for each cancer tissue in The Cancer Genome Atlas as ready-to-analyze MultiAssayExperiment objects and demonstrate in these and other datasets how the software simplifies data representation, statistical analysis, and visualization. The MultiAssayExperiment Bioconductor package reduces major obstacles to efficient, scalable, and reproducible statistical analysis of multiomics data and enhances data science applications of multiple omics datasets. Cancer Res; 77(21); e39-42. ©2017 AACR . ©2017 American Association for Cancer Research.
Tsunami-induced boulder transport - combining physical experiments and numerical modelling
Oetjen, Jan; Engel, Max; May, Simon Matthias; Schüttrumpf, Holger; Brueckner, Helmut; Prasad Pudasaini, Shiva
2016-04-01
Coasts are crucial areas for living, economy, recreation, transportation, and various sectors of industry. Many of them are exposed to high-energy wave events. With regard to the ongoing population growth in low-elevation coastal areas, the urgent need for developing suitable management measures, especially for hazards like tsunamis, becomes obvious. These measures require supporting tools which allow an exact estimation of impact parameters like inundation height, inundation area, and wave energy. Focussing on tsunamis, geological archives can provide essential information on frequency and magnitude on a longer time scale in order to support coastal hazard management. While fine-grained deposits may quickly be altered after deposition, multi-ton coarse clasts (boulders) may represent an information source on past tsunami events with a much higher preservation potential. Applying numerical hydrodynamic coupled boulder transport models (BTM) is a commonly used approach to analyse characteristics (e.g. wave height, flow velocity) of the corresponding tsunami. Correct computations of tsunamis and the induced boulder transport can provide essential event-specific information, including wave heights, runup and direction. Although several valuable numerical models for tsunami-induced boulder transport exist (e. g. Goto et al., 2007; Imamura et al., 2008), some important basic aspects of both tsunami hydrodynamics and corresponding boulder transport have not yet been entirely understood. Therefore, our project aims at these questions in four crucial aspects of boulder transport by a tsunami: (i) influence of sediment load, (ii) influence of complex boulder shapes other than idealized rectangular shapes, (iii) momentum transfers between multiple boulders, and (iv) influence of non-uniform bathymetries and topographies both on tsunami and boulder. The investigation of these aspects in physical experiments and the correct implementation of an advanced model is an urgent need
Numerical Forecasting Experiment of the Wave Energy Resource in the China Sea
Directory of Open Access Journals (Sweden)
Chong Wei Zheng
2016-01-01
Full Text Available The short-term forecasting of wave energy is important to provide guidance for the electric power operation and power transmission system and to enhance the efficiency of energy capture and conversion. This study produced a numerical forecasting experiment of the China Sea wave energy using WAVEWATCH-III (WW3, the latest version 4.18 wave model driven by T213 (WW3-T213 and T639 (WW3-T639 wind data separately. Then the WW3-T213 and WW3-T639 were verified and compared to build a short-term wave energy forecasting structure suited for the China Sea. Considering the value of wave power density (WPD, “wave energy rose,” daily and weekly total storage and effective storage of wave energy, this study also designed a series of short-term wave energy forecasting productions. Results show that both the WW3-T213 and WW3-T639 exhibit a good skill on the numerical forecasting of the China Sea WPD, while the result of WW3-T639 is much better. Judging from WPD and daily and weekly total storage and effective storage of wave energy, great wave energy caused by cold airs was found. As there are relatively frequent cold airs in winter, early spring, and later autumn in the China Sea and the surrounding waters, abundant wave energy ensues.
Haeufle, D F B; Günther, M; Blickhan, R; Schmitt, S
2011-01-01
Recently, the hyperbolic Hill-type force-velocity relation was derived from basic physical components. It was shown that a contractile element CE consisting of a mechanical energy source (active element AE), a parallel damper element (PDE), and a serial element (SE) exhibits operating points with hyperbolic force-velocity dependency. In this paper, the contraction dynamics of this CE concept were analyzed in a numerical simulation of quick release experiments against different loads. A hyperbolic force-velocity relation was found. The results correspond to measurements of the contraction dynamics of a technical prototype. Deviations from the theoretical prediction could partly be explained by the low stiffness of the SE, which was modeled analog to the metal spring in the hardware prototype. The numerical model and hardware prototype together, are a proof of this CE concept and can be seen as a well-founded starting point for the development of Hill-type artificial muscles. This opens up new vistas for the technical realization of natural movements with rehabilitation devices. © 2011 IEEE
International Nuclear Information System (INIS)
Hu, Q; Li, Y; Pan, H L; Liu, J T; Zhuang, B T
2015-01-01
Vane type propellant management device (PMD) is one of the key components of the vane-type surface tension tank (STT), and its fluid orbital performance directly determines the STT's success or failure. In present paper, numerical analysis and microgravity experiment study on fluid orbital performance of a vane type PMD were carried out. By using two-phase flow model of volume of fluid (VOF), fluid flow characteristics in the tank with the vane type PMD were numerically calculated, and the rules of fluid transfer and distribution were gotten. A abbreviate model test system of the vane type PMD is established and microgravity drop tower tests were performed, then fluid management and transmission rules of the vane type PMD were obtained under microgravity environment. The analysis and tests results show that the vane type PMD has good and initiative fluid orbital management ability and meets the demands of fluid orbital extrusion in the vane type STT. The results offer valuable guidance for the design and optimization of the new generation of vane type PMD, and also provide a new approach for fluid management and control in space environment
A numerical tool for reproducing driver behaviour: experiments and predictive simulations.
Casucci, M; Marchitto, M; Cacciabue, P C
2010-03-01
This paper presents the simulation tool called SDDRIVE (Simple Simulation of Driver performance), which is the numerical computerised implementation of the theoretical architecture describing Driver-Vehicle-Environment (DVE) interactions, contained in Cacciabue and Carsten [Cacciabue, P.C., Carsten, O. A simple model of driver behaviour to sustain design and safety assessment of automated systems in automotive environments, 2010]. Following a brief description of the basic algorithms that simulate the performance of drivers, the paper presents and discusses a set of experiments carried out in a Virtual Reality full scale simulator for validating the simulation. Then the predictive potentiality of the tool is shown by discussing two case studies of DVE interactions, performed in the presence of different driver attitudes in similar traffic conditions.
Experiment and Lattice Boltzmann numerical study on nanofluids flow in a micromodel as porous medium
Meghdadi Isfahani, A. H.; Afrand, Masoud
2017-10-01
Al2O3 nanofluids flow has been studied in etched glass micromodel which is idealization of porous media by using a pseudo 2D Lattice Boltzmann Method (LBM). The predictions were compared with experimental results. Pressure drop / flow rate relations have been measured for pure water and Al2O3 nanofluids. Because the size of Al2O3 nanoparticles is tiny enough to permit through the pore throats of the micromodel, blockage does not occur and the permeability is independent of the nanofluid volume fraction. Therefore, the nanofluid behaves as a single phase fluid, and a single phase LBM is able to simulate the results of this experiment. Although the flow in micromodels is 3D, we showed that 2D LBM can be used provided an effective viscous drag force, representing the effect of the third dimension, is considered. Good qualitative and quantitative agreement is seen between the numerical and experimental results.
Numerical analysis of experiments with gas injection into liquid metal coolant
International Nuclear Information System (INIS)
Usov, E V; Lobanov, P D; Pribaturin, N A; Mosunova, N A; Chuhno, V I; Kutlimetov, A E
2016-01-01
Presented paper contains results of a numerical analysis of experiments with gas injection in water and liquid metal which have been performed at the Institute of Thermophysics Russian Academy of Science (IT RAS). Obtained experimental data are very important to predict processes that take place in the BREST-type reactor during the hypothetical accident with damage of the steam generator tubes, and may be used as a benchmark to validate thermo-hydraulic codes. Detailed description of models to simulate transport of gas phase in a vertical liquid column is presented in a current paper. Two-fluid model with closing relation for wall friction and interface friction coefficients was used to simulate processes which take place in a liquid during injection of gaseous phase. It has being shown that proposed models allow obtaining a good agreement between experimental data and calculation results. (paper)
Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS
Froidevaux, D
2011-01-01
Integration of Detectors Into a Large Experiment: Examples From ATLAS andCMS, part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B2: Detectors for Particles and Radiation. Part 2: Systems and Applications'. This document is part of Part 2 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '5 Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS' with the content: 5 Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS 5.1 Introduction 5.1.1 The context 5.1.2 The main initial physics goals of ATLAS and CMS at the LHC 5.1.3 A snapshot of the current status of the ATLAS and CMS experiments 5.2 Overall detector concept and magnet systems 5.2.1 Overall detector concept 5.2.2 Magnet systems 5.2.2.1 Rad...
Elkhoury, J. E.; Detwiler, R. L.; Serajian, V.; Bruno, M. S.
2012-12-01
Geothermal energy resources are more widespread than previously thought and have the potential for providing a significant amount of sustainable clean energy worldwide. In particular, hot permeable sedimentary formations provide many advantages over traditional geothermal recovery and enhanced geothermal systems in low permeability crystalline formations. These include: (1) eliminating the need for hydraulic fracturing, (2) significant reduction in risk for induced seismicity, (3) reducing the need for surface wastewater disposal, (4) contributing to decreases in greenhouse gases, and (5) potential use for CO2 sequestration. Advances in horizontal drilling, completion, and production technology from the oil and gas industry can now be applied to unlock these geothermal resources. Here, we present experimental results from a laboratory scale circulation system and numerical simulations aimed at quantifying the heat transfer capacity of sedimentary rocks. Our experiments consist of fluid flow through a saturated and pressurized sedimentary disc of 23-cm diameter and 3.8-cm thickness heated along its circumference at a constant temperature. Injection and production ports are 7.6-cm apart in the center of the disc. We used DI de-aired water and mineral oil as working fluids and explored temperatures from 20 to 150 oC and flow rates from 2 to 30 ml/min. We performed experiments on sandstone samples (Castlegate and Kirby) with different porosity, permeability and thermal conductivity to evaluate the effect of hydraulic and thermal properties on the heat transfer capacity of sediments. The producing fluid temperature followed an exponential form with time scale transients between 15 and 45 min. Steady state outflow temperatures varied between 60% and 95% of the set boundary temperature, higher percentages were observed for lower temperatures and flow rates. We used the flow and heat transport simulator TOUGH2 to develop a numerical model of our laboratory setting. Given
Energy Technology Data Exchange (ETDEWEB)
Saar, Martin O. [ETH Zurich (Switzerland); Univ. of Minnesota, Minneapolis, MN (United States); Seyfried, Jr., William E. [Univ. of Minnesota, Minneapolis, MN (United States); Longmire, Ellen K. [Univ. of Minnesota, Minneapolis, MN (United States)
2016-06-24
A total of 12 publications and 23 abstracts were produced as a result of this study. In particular, the compilation of a thermodynamic database utilizing consistent, current thermodynamic data is a major step toward accurately modeling multi-phase fluid interactions with solids. Existing databases designed for aqueous fluids did not mesh well with existing solid phase databases. Addition of a second liquid phase (CO2) magnifies the inconsistencies between aqueous and solid thermodynamic databases. Overall, the combination of high temperature and pressure lab studies (task 1), using a purpose built apparatus, and solid characterization (task 2), using XRCT and more developed technologies, allowed observation of dissolution and precipitation processes under CO2 reservoir conditions. These observations were combined with results from PIV experiments on multi-phase fluids (task 3) in typical flow path geometries. The results of the tasks 1, 2, and 3 were compiled and integrated into numerical models utilizing Lattice-Boltzmann simulations (task 4) to realistically model the physical processes and were ultimately folded into TOUGH2 code for reservoir scale modeling (task 5). Compilation of the thermodynamic database assisted comparisons to PIV experiments (Task 3) and greatly improved Lattice Boltzmann (Task 4) and TOUGH2 simulations (Task 5). PIV (Task 3) and experimental apparatus (Task 1) have identified problem areas in TOUGHREACT code. Additional lab experiments and coding work has been integrated into an improved numerical modeling code.
Numerical simulation of mud erosion rate in sand-mud alternate layer and comparison with experiment
Yoshida, T.; Yamaguchi, T.; Oyama, H.; Sato, T.
2015-12-01
For gas production from methane hydrates in sand-mud alternate layers, depressurization method is expected as feasible. After methane hydrate is dissociated, gas and water flow in pore space. There is a concern about the erosion of mud surface and it may result in flow blockage that disturbs the gas production. As a part of a Japanese National hydrate research program (MH21, funded by METI), we developed a numerical simulation of water-induced mud erosion in pore-scale sand-mud domains to model such mud erosion. The size of which is of the order of 100 micro meter. Water flow is simulated using a lattice Boltzmann method (LBM) and mud surface is treated as solid boundary with arbitrary shape, which changes with time. Periodic boundary condition is adopted at the domain boundaries, except for the surface of mud layers and the upper side. Shear stress acting on the mud surface is calculated using a momentum-exchange method. Mud layer is eroded when the shear stress exceeds a threshold coined a critical shear stress. In this study, we compared the simulated mud erosion rate with experimental data acquired from an experiment using artificial sand-mud core. As a result, the simulated erosion rate agrees well with that of the experiment.
Subsampled Numerical Experiments as a Guide for Field Deployment of Thermistor Chains
Shaw, Justin; Stastna, Marek
2017-11-01
Thermistor chains are a standard tool for recording temperature profiles in geophysical flows. Density values can be inferred from readings and the resulting density field analyzed for the passage of internal waves, Kelvin-Helmholtz billows, and other dynamic events. The number and spacing of the thermistors, both on and between chains, determines which events can be identified in the dataset. We examine the effect of changing these variables by subsampling a set of numerical experiments to simulate thermistor chain locations. A pseudo spectral method was used to solve the incompressible Navier-Stokes equations under the Boussinesq approximation. The resulting flows are a set of high resolution seiches where the depth was held constant across experiments, and the length was varied. Sampling a known, commonly occurring flow with relatively simple geometry allows for a clear analysis of the effects of thermistor placement in the capture of dynamic events. We will discuss three dimensional deployment strategies, as well as EOF and DMD analyses if there is time. Funded by a Grant from the National Sciences and Engineering Research Council of Canada.
Isotopic fractionation of gases during its migration: experiments and 2D numerical simulation
Kara, S.; Prinzhofer, A.
2003-04-01
Several works have been developed in the last decade on the experimental isotope fractionation of gases during migration (Prinzhofer et al., 1997 and Zhang &Krooss, 2001 among others). We add to these results new experiments on diffusion of CO_2, which becomes currently a crucial subject for environmental purpose. Our experiments showed that transport by diffusion of CO_2 through a water saturated shale induces a significant and systematic carbon isotopic fractionation with heavier (13C enriched) CO_2 migrating first. In all experiments, significant isotope fractionation was found but still remains without quantitative interpretation. To interpret these data, we developed a 2D numerical model at the pore scale. The general principle of this model is the study of transport by water solubilization/diffusion of gas in a capillary saturated with water with two different media : a mobile zone representing free water and a immobile zone representing bounded water. The model takes also into account solubilization coefficients of gas in water, as well as the migration distance and the volume of upstream and downstream reservoirs. Using our numerical model, we could reproduce the evolution of isotopic fractionations and the velocity of CO_2 migration versus the production factor F (proportion of diffused gas). We determined some physical parameters of the porous medium (bentonite) which are not directly measurable at the present time. Furthermore, we used these parameters to reproduce the curves of isotopic fractionation obtained by Pernaton (1998) on methane migration with the same porous rock. We used also a modified version of this model with infinite reservoirs to reproduce the curves of isotopic fractionation of Zhang &Krooss (2001). Application of this model to geological scale is under progress, in order to implement it into sedimentary basins modelling. REFERENCES: Zhang T. and Krooss M. (2001). Geochim. Cosmochim. Acta, Vol. 65, No.16, pp. 2723-2742. Pernaton E
Doehmann, M.; Brune, S.; Nardini, L.; Rybacki, E.; Dresen, G.
2017-12-01
Strain localization is an ubiquitous process in earth materials observed over a broad range of scales in space and time. Localized deformation and the formation of shear zones and faults typically involves material softening by various processes, like shear heating and grain size reduction. Numerical modeling enables us to study the complex physical and chemical weakening processes by separating the effect of individual parameters and boundary conditions. Using simple piece-wise linear functions for the parametrization of weakening processes allows studying a system at a chosen (lower) level of complexity (e.g. Cyprych et al., 2016). In this study, we utilize a finite element model to test two weakening laws that reduce the strength of the material depending on either the I) amount of accumulated strain or II) deformational work. Our 2D Cartesian models are benchmarked to single inclusion torsion experiments performed at elevated temperatures of 900 °C and pressures of up to 400 MPa (Rybacki et al., 2014). The experiments were performed on Carrara marble samples containing a weak Solnhofen limestone inclusion at a maximum strain rate of 2.0*10-4 s-1. Our models are designed to reproduce shear deformation of a hollow cylinder equivalent to the laboratory setup, such that material leaving one side of the model in shear direction enters again on the opposite side using periodic boundary conditions. Similar to the laboratory tests, we applied constant strain rate and constant stress boundary conditions.We use our model to investigate the time-dependent distribution of stress and strain and the effect of different parameters. For instance, inclusion rotation is shown to be strongly dependent on the viscosity ratio between matrix and inclusion and stronger ductile weakening increases the localization rate while decreasing shear zone width. The most suitable weakening law for representation of ductile rock is determined by combining the results of parameter tests with
Directory of Open Access Journals (Sweden)
K. Schneider-Zapp
2010-05-01
Full Text Available Evaporation is an important process in soil-atmosphere interaction. The determination of hydraulic properties is one of the crucial parts in the simulation of water transport in porous media. Schneider et al. (2006 developed a new evaporation method to improve the estimation of hydraulic properties in the dry range. In this study we used numerical simulations of the experiment to study the physical dynamics in more detail, to optimise the boundary conditions and to choose the optimal combination of measurements. The physical analysis exposed, in accordance to experimental findings in the literature, two different evaporation regimes: (i a soil-atmosphere boundary layer dominated regime (regime I close to saturation and (ii a hydraulically dominated regime (regime II. During this second regime a drying front (interface between unsaturated and dry zone with very steep gradients forms which penetrates deeper into the soil as time passes. The sensitivity analysis showed that the result is especially sensitive at the transition between the two regimes. By changing the boundary conditions it is possible to force the system to switch between the two regimes, e.g. from II back to I. Based on this findings a multistep experiment was developed. The response surfaces for all parameter combinations are flat and have a unique, localised minimum. Best parameter estimates are obtained if the evaporation flux and a potential measurement in 2 cm depth are used as target variables. Parameter estimation from simulated experiments with realistic measurement errors with a two-stage Monte-Carlo Levenberg-Marquardt procedure and manual rejection of obvious misfits lead to acceptable results for three different soil textures.
Experiment and numerical simulation of welding induced damage: stainless steel 15-5PH
International Nuclear Information System (INIS)
Wu, T.
2007-11-01
The objective of this study is the prediction of damage and residual stresses induced by hot processing which leads to phase transformation in martensitic stainless steel. This study firstly concerns the modelling of the damage of material induced by a complex history of thermo-elastoplastic multiphase in heat-affected-zone (HAZ) of welding. In this work, a two-scale mode of elastoplastic damage multiphase was developed in the framework of thermodynamics of irreversible process. The constitutive equations are coupling with ductile damage, elasto-plasticity, phase transformation, and transformation plasticity. Besides, a damage equation was proposed based on the Lemaitre's damage model in the framework of continuum damage mechanics. The experiments of 15-5PH were implemented for the identification of phase transformation, transformation plasticity and damage models. Tensile tests of round specimens were used to identify the parameters of damage model as well as mechanical behaviours at various temperatures. Tests of flat notched specimen were designed to provide the validation of damage model and strain localization using three dimensional image correlation technologies. In addition, microscopic analysis was performed to provide microstructure characterization of 15-5PH and to discover the damage mechanism. Finally the numerical simulation was performed in the code CAST3M of CEA. On the one hand, numerical verification of the flat notched plates was implemented and compared with experimental results. On the other hand, we used the two-scale model including phase transformation, transformation plasticity and damage to simulate the level of residual stresses of a disk made of 15-5PH metal heated by laser. The internal variables, such as strain, stress, damage, were successfully traced in the simulation of two-scale model. The simulation results showed the transformation plasticity changes the level of residual stresses and should not be negligible; damage decreases
Experiences with integral microelectronics on smart structures for space
Nye, Ted; Casteel, Scott; Navarro, Sergio A.; Kraml, Bob
1995-05-01
One feature of a smart structure implies that some computational and signal processing capability can be performed at a local level, perhaps integral to the controlled structure. This requires electronics with a minimal mechanical influence regarding structural stiffening, heat dissipation, weight, and electrical interface connectivity. The Advanced Controls Technology Experiment II (ACTEX II) space-flight experiments implemented such a local control electronics scheme by utilizing composite smart members with integral processing electronics. These microelectronics, tested to MIL-STD-883B levels, were fabricated with conventional thick film on ceramic multichip module techniques. Kovar housings and aluminum-kapton multilayer insulation was used to protect against harsh space radiation and thermal environments. Development and acceptance testing showed the electronics design was extremely robust, operating in vacuum and at temperature range with minimal gain variations occurring just above room temperatures. Four electronics modules, used for the flight hardware configuration, were connected by a RS-485 2 Mbit per second serial data bus. The data bus was controlled by Actel field programmable gate arrays arranged in a single master, four slave configuration. An Intel 80C196KD microprocessor was chosen as the digital compensator in each controller. It was used to apply a series of selectable biquad filters, implemented via Delta Transforms. Instability in any compensator was expected to appear as large amplitude oscillations in the deployed structure. Thus, over-vibration detection circuitry with automatic output isolation was incorporated into the design. This was not used however, since during experiment integration and test, intentionally induced compensator instabilities resulted in benign mechanical oscillation symptoms. Not too surprisingly, it was determined that instabilities were most detectable by large temperature increases in the electronics, typically
International Nuclear Information System (INIS)
Cash, J.R.; Raptis, A.D.; Simos, T.E.
1990-01-01
An efficient algorithm is described for the accurate numerical integration of the one-dimensional Schroedinger equation. This algorithm uses a high-order, variable step Runge-Kutta like method in the region where the potential term dominates, and an exponential or Bessel fitted method in the asymptotic region. This approach can be used to compute scattering phase shifts in an efficient and reliable manner. A Fortran program which implements this algorithm is provided and some test results are given. (orig.)
McGhee, David S.
2005-01-01
Today's NASA is facing significant challenges and changes. The Exploration initiative indicates a large increase in projects with limited increase in budget. The Columbia report has criticized NASA for its lack of insight and technical integration impacting its ability to provide safety. The Aldridge report is advocating NASA find new ways of doing business. Very early in the Space Launch Initiative (SLI) program a small team of engineers at MSFC were asked to propose a process for performing a system level assessment of a launch vehicle. The request was aimed primarily at providing insight and making NASA a "smart buyer." Out of this effort the VIPA team was created. The difference between the VIPA effort and many integration attempts is that VIPA focuses on using experienced people from various disciplines and a process which focuses them on a technically integrated assessment. Most previous attempts have focused on developing an all encompassing software tool. In addition, VIPA anchored its process formulation in the experience of its members and in early developmental Space Shuttle experience. The primary reference for this is NASA-TP-2001-210092, "Launch Vehicle Design Process: Characterization, Technical Integration, and Lessons Learned," and discussions with its authors. The foundations of VIPA's process are described. The VIPA team also recognized the need to drive detailed analysis earlier in the design process. Analyses and techniques typically done in later design phases, are brought forward using improved computing technology. The intent is to allow the identification of significant sensitivities, trades, and design issues much earlier in the program. This process is driven by the T-model for Technical Integration described in the aforementioned reference. VIPA's approach to performing system level technical integration is discussed in detail. Proposed definitions are offered to clarify this discussion and the general systems integration dialog. VIPA
Javernick, Luke; Redolfi, Marco; Bertoldi, Walter
2018-05-01
New data collection techniques offer numerical modelers the ability to gather and utilize high quality data sets with high spatial and temporal resolution. Such data sets are currently needed for calibration, verification, and to fuel future model development, particularly morphological simulations. This study explores the use of high quality spatial and temporal data sets of observed bed load transport in braided river flume experiments to evaluate the ability of a two-dimensional model, Delft3D, to predict bed load transport. This study uses a fixed bed model configuration and examines the model's shear stress calculations, which are the foundation to predict the sediment fluxes necessary for morphological simulations. The evaluation is conducted for three flow rates, and model setup used highly accurate Structure-from-Motion (SfM) topography and discharge boundary conditions. The model was hydraulically calibrated using bed roughness, and performance was evaluated based on depth and inundation agreement. Model bed load performance was evaluated in terms of critical shear stress exceedance area compared to maps of observed bed mobility in a flume. Following the standard hydraulic calibration, bed load performance was tested for sensitivity to horizontal eddy viscosity parameterization and bed morphology updating. Simulations produced depth errors equal to the SfM inherent errors, inundation agreement of 77-85%, and critical shear stress exceedance in agreement with 49-68% of the observed active area. This study provides insight into the ability of physically based, two-dimensional simulations to accurately predict bed load as well as the effects of horizontal eddy viscosity and bed updating. Further, this study highlights how using high spatial and temporal data to capture the physical processes at work during flume experiments can help to improve morphological modeling.
Dynamics of soil water evaporation during soil drying: laboratory experiment and numerical analysis.
Han, Jiangbo; Zhou, Zhifang
2013-01-01
Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3.
Energy Technology Data Exchange (ETDEWEB)
Tsuchiya, T [Dia Consultants Company, Tokyo (Japan)
1996-10-01
Nonlinear full-wave tomography (FWT) is under investigation to improve the estimation accuracy of Vp/Vs distributions. Full-wave tomography is one of the underground structure exploration methods mainly using Tarantola`s nonlinear local optimization method (LOM). Numerical experiment for FWT was carried out assuming relatively weak nonlinear underground structure. In the case of inversion by local optimization method, adequate preconditioning is important. Utilization of geological information is also effective in estimating low-frequency components of a model. As far as data are obtained under proper observation arrangement, even in actual field, precise estimation of Vp/Vs distributions is possible by FWT using explosion in a hole as wave source. In full-wave tomography, selection of observation arrangement is essential for both Vp and Vs. However, the proper arrangement is different between Vp and Vs. Approach to different analyses for Vp and Vs is also necessary by using only proper data for Vp and Vs among obtained data sets. 4 figs.
Directory of Open Access Journals (Sweden)
Yang Xu
2017-11-01
Full Text Available To improve the efficiency of utilizing water resources in arid areas, the mechanism of artificial recharge effecting on groundwater reservoir was analyzed in this research. Based on a generalized groundwater reservoir in a two-dimensional sand tank model, different scenarios of the infiltration basin location and recharge intensity are designed to study how to improve the efficiency of groundwater reservoir artificial recharge. The effective storage capacity and the effective storage rate are taken as the main parameters to analyze the relation between recharge water volume and storage capacity. By combining with groundwater flow system theory, FEFLOW (Finite Element subsurface FLOW system is adopted to set up the groundwater numerical model. It is used to verify the experiment results and to make deep analysis on the rule of water table fluctuations and groundwater movement in the aquifer. Based on the model, different scenarios are designed to examine the combined effect of recharge intensity and intermittent periods. The research results show that: the distance between infiltration basin and pumping well should be shortened appropriately, but not too close; increasing recharge intensity helps to enlarge the effective storage capacity, but it can also reduce the effective storage rate, which goes against the purpose of effective utilization of water resources; and, the recharge intensity and recharge duration should be given full consideration by the actual requirements when we take the approach of intermittent recharge to make a reasonable choice.
International Nuclear Information System (INIS)
Kiseleva, L.G.; Orlov, V.V.
1988-01-01
The numerical-experiment approach in the framework of the general gravitational three-body problem has been used to investigate the dynamical evolution of triple systems of gaseous protogalactic fragments. The masses of the fragments are equal, the initial velocities zero. The initial positions were specified by uniform scanning in the region D of all possible initial configurations. Calculations were continued until the first two-body encounter of the fragments. Different values of the fragment radii at this times were considered, namely, r in the interval [0.001, 0.1]d, where d is the mean diameter of the system. It is shown that for such r the pair of gaseous fragments coalesces in the majority of cases (from 50.2% for r = 0.001d to 96.7% for r = 0.1d). The mean specific angular momentum of their relative motion, which becomes spin angular momentum of the coalescence product, is (0.8 +- 1.0)/centered dot/10 29 /root/μl cm 2 sec for the most probable value r = 10l kpc (the masses of the fragments are 5/centered dot/10 10 μM/circled dot/; l and μ are scale factors), this agreeing in order of magnitude with the specific angular momenta of disk galaxies if l, μ /approximately/ 1. For each value of r, a continuous zone of initial configurations corresponding to coalescences is identified in the region D
Energy Technology Data Exchange (ETDEWEB)
Hansen, C., E-mail: hansec@uw.edu [PSI-Center, University of Washington, Seattle, Washington 98195 (United States); Columbia University, New York, New York 10027 (United States); Victor, B.; Morgan, K.; Hossack, A.; Sutherland, D. [HIT-SI Group, University of Washington, Seattle, Washington 98195 (United States); Jarboe, T.; Nelson, B. A. [HIT-SI Group, University of Washington, Seattle, Washington 98195 (United States); PSI-Center, University of Washington, Seattle, Washington 98195 (United States); Marklin, G. [PSI-Center, University of Washington, Seattle, Washington 98195 (United States)
2015-05-15
We present application of three scalar metrics derived from the Biorthogonal Decomposition (BD) technique to evaluate the level of agreement between macroscopic plasma dynamics in different data sets. BD decomposes large data sets, as produced by distributed diagnostic arrays, into principal mode structures without assumptions on spatial or temporal structure. These metrics have been applied to validation of the Hall-MHD model using experimental data from the Helicity Injected Torus with Steady Inductive helicity injection experiment. Each metric provides a measure of correlation between mode structures extracted from experimental data and simulations for an array of 192 surface-mounted magnetic probes. Numerical validation studies have been performed using the NIMROD code, where the injectors are modeled as boundary conditions on the flux conserver, and the PSI-TET code, where the entire plasma volume is treated. Initial results from a comprehensive validation study of high performance operation with different injector frequencies are presented, illustrating application of the BD method. Using a simplified (constant, uniform density and temperature) Hall-MHD model, simulation results agree with experimental observation for two of the three defined metrics when the injectors are driven with a frequency of 14.5 kHz.
Dynamics of Soil Water Evaporation during Soil Drying: Laboratory Experiment and Numerical Analysis
Han, Jiangbo; Zhou, Zhifang
2013-01-01
Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. PMID:24489492
Numerical simulations of recent proton acceleration experiments with sub-100 TW laser systems
International Nuclear Information System (INIS)
Sinigardi, Stefano
2016-01-01
Recent experiments carried out at the Italian National Research Center, National Optics Institute Department in Pisa, are showing interesting results regarding maximum proton energies achievable with sub-100 TW laser systems. While laser systems are being continuously upgraded in laboratories around the world, at the same time a new trend on stabilizing and making ion acceleration results reproducible is growing in importance. Almost all applications require a beam with fixed performance, so that the energy spectrum and the total charge exhibit moderate shot to shot variations. This result is surely far from being achieved, but many paths are being explored in order to reach it. Some of the reasons for this variability come from fluctuations in laser intensity and focusing, due to optics instability. Other variation sources come from small differences in the target structure. The target structure can vary substantially, when it is impacted by the main pulse, due to the prepulse duration and intensity, the shape of the main pulse and the total energy deposited. In order to qualitatively describe the prepulse effect, we will present a two dimensional parametric scan of its relevant parameters. A single case is also analyzed with a full three dimensional simulation, obtaining reasonable agreement between the numerical and the experimental energy spectrum.
Integration of numerical modeling and observations for the Gulf of Naples monitoring network
Iermano, I.; Uttieri, M.; Zambianchi, E.; Buonocore, B.; Cianelli, D.; Falco, P.; Zambardino, G.
2012-04-01
Lethal effects of mineral oils on fragile marine and coastal ecosystems are now well known. Risks and damages caused by a maritime accident can be reduced with the help of better forecasts and efficient monitoring systems. The MED project TOSCA (Tracking Oil Spills and Coastal Awareness Network), which gathers 13 partners from 4 Mediterranean countries, has been designed to help create a better response system to maritime accidents. Through the construction of an observational network, based on state of the art technology (HF radars and drifters), TOSCA provides real-time observations and forecasts of the Mediterranean coastal marine environmental conditions. The system is installed and assessed in five test sites on the coastal areas of oil spill outlets (Eastern Mediterranean) and on high traffic areas (Western Mediterranean). The Gulf of Naples, a small semi-closed basin opening to the Tyrrhenian Sea is one of the five test-sites. It is of particular interest from both the environmental point of view, due to peculiar ecosystem properties in the area, and because it sustains important touristic and commercial activities. Currently the Gulf of Naples monitoring network is represented by five automatic weather stations distributed along the coasts of the Gulf, one weather radar, two tide gauges, one waverider buoy, and moored physical, chemical and bio-optical instrumentation. In addition, a CODAR-SeaSonde HF coastal radar system composed of three antennas is located in Portici, Massa Lubrense and Castellammare. The system provides hourly data of surface currents over the entire Gulf with a 1km spatial resolution. A numerical modeling implementation based on Regional Ocean Modeling System (ROMS) is actually integrated in the Gulf of Naples monitoring network. ROMS is a 3-D, free-surface, hydrostatic, primitive equation, finite difference ocean model. In our configuration, the model has high horizontal resolution (250m), and 30 sigma levels in the vertical. Thanks
Numerical solution of the potential problem by integral equations without Green's functions
International Nuclear Information System (INIS)
De Mey, G.
1977-01-01
An integral equation technique will be presented to solve Laplace's equation in a two-dimensional area S. The Green's function has been replaced by a particular solution of Laplace equation in order to establish the integral equation. It is shown that accurate results can be obtained provided the pivotal elimination method is used to solve the linear algebraic set
Block-pulse functions approach to numerical solution of Abel’s integral equation
Directory of Open Access Journals (Sweden)
Monireh Nosrati Sahlan
2015-12-01
Full Text Available This study aims to present a computational method for solving Abel’s integral equation of the second kind. The introduced method is based on the use of Block-pulse functions (BPFs via collocation method. Abel’s integral equations as singular Volterra integral equations are hard and heavy in computation, but because of the properties of BPFs, as is reported in examples, this method is more efficient and more accurate than some other methods for solving this class of integral equations. On the other hand, the benefit of this method is low cost of computing operations. The applied method transforms the singular integral equation into triangular linear algebraic system that can be solved easily. An error analysis is worked out and applications are demonstrated through illustrative examples.
Limaye, A. B.; Komatsu, Y.; Suzuki, K.; Paola, C.
2017-12-01
Turbidity currents deliver clastic sediment from continental margins to the deep ocean, and are the main driver of landscape and stratigraphic evolution in many low-relief, submarine environments. The sedimentary architecture of turbidites—including the spatial organization of coarse and fine sediments—is closely related to the aggradation, scour, and lateral shifting of channels. Seismic stratigraphy indicates that submarine, meandering channels often aggrade rapidly relative to lateral shifting, and develop channel sand bodies with high vertical connectivity. In comparison, the stratigraphic architecture developed by submarine, braided is relatively uncertain. We present a new stratigraphic model for submarine braided channels that integrates predictions from laboratory experiments and flow modeling with constraints from sediment cores. In the laboratory experiments, a saline density current developed subaqueous channels in plastic sediment. The channels aggraded to form a deposit with a vertical scale of approximately five channel depths. We collected topography data during aggradation to (1) establish relative stratigraphic age, and (2) estimate the sorting patterns of a hypothetical grain size distribution. We applied a numerical flow model to each topographic surface and used modeled flow depth as a proxy for relative grain size. We then conditioned the resulting stratigraphic model to observed grain size distributions using sediment core data from the Nankai Trough, offshore Japan. Using this stratigraphic model, we establish new, quantitative predictions for the two- and three-dimensional connectivity of coarse sediment as a function of fine-sediment fraction. Using this case study as an example, we will highlight outstanding challenges in relating the evolution of low-relief landscapes to the stratigraphic record.
International Nuclear Information System (INIS)
Richard, B.
2012-01-01
The good knowledge of nuclear data, input parameters for the neutron transport calculation codes, is necessary to support the advances of the nuclear industry. The purpose of this work is to bring pertinent information regarding the nuclear data integral validation process. Reactivity worth measurements have been performed on the Caliban reactor, they concern four materials of interest for the nuclear industry: gold, lutetium, plutonium and uranium 238. Experiments which have been conducted in order to improve the characterization of the core are also described and discussed, the latter are necessary to the good interpretation of reactivity worth measurements. The experimental procedures are described with their associated uncertainties, measurements are then compared to numerical results. The methods used in numerical calculations are reported, especially the multigroup cross sections generation for deterministic codes. The modeling of the experiments is presented along with the associated uncertainties. This comparison led to an interpretation concerning the qualification of nuclear data libraries. Discrepancies are reported, discussed and justify the need of such experiments. (author) [fr
Yang, C.; Romanak, K.; Hovorka, S.
2009-12-01
Soil gas monitoring is one cost-effective approach to detect CO2 leak at geological sequestration sites. Therefore understanding CO2 gas transport in soil zones is important for detection of CO2 leaks. A field experiment of a small CO2 release was conducted at the Brackenridge Field Laboratory, the University of Texas at Austin. The field site consists of one injection well, two sensor wells and one gas station well (Figure 1). The injection well was completed with a PVC pipe to a depth of 1.1 m below surface. CO2 sensors were deployed in sensor wells about 42 cm from the injection well at depths of 1.1 m having no subsurface PVC pipes but only a PVC protector cap at the surface. The gas monitoring station about 72 cm away from the injection well contains 3 copper tubes each set at different depths in sand pack isolated with bentonite clay. The CO2 release experiment started on March 4, 2009. A total 36.76 liters of CO2 were injected at 1 m depth at a rate of 100 ml/minute for 6 hours. Subsurface CO2 gas concentrations (before, during, and after the injection) were continuously monitored in sensor wells. Real-time CO2 concentrations were monitored at the gas station using an SRI 8610 gas chromatograph (GC) fitted with flame ionization detector (FID) and a thermal conductivity detector (TCD). A numerical model was constructed to simulate CO2 release experiments. The model takes into account CO2 diffusion and dissolution in pore water. Air in the pore space is assumed stagnant. Model domain consists of four soil layers and one atmospheric layer. The groundwater table is about 2.4 meters below ground surface. The model was calibrated with respect to diffusion coefficient (transport parameter) and the injection rate (mass parameter). Model results fit well with CO2 measurements at the sensor wells and the gas station. However, the calibrated injection rate underestimates measured injection rate.
Energy Technology Data Exchange (ETDEWEB)
Senechal, U.; Breitkopf, C. [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik
2011-07-01
Temporal analysis of products (TAP) is a valuable tool for characterization of porous catalytic structures. Established TAP-modeling requires a spatially constant diffusion coefficient and neglect convective flows, which is only valid in Knudsen diffusion regime. Therefore in experiments, the number of molecules per pulse must be chosen accordingly. New approaches for variable process conditions are highly required. Thus, a new theoretical model is developed for estimating the number of molecules per pulse to meet these requirements under any conditions and at any time. The void volume is calculated as the biggest sphere fitting between three pellets. The total number of pulsed molecules is assumed to fill the first void volume at the inlet immediately. Molecule numbers from these calculations can be understood as maximum possible molecules at any time in the reactor to be in Knudsen diffusion regime, i.e., above the Knudsen number of 2. Moreover, a new methodology for generating a full three-dimensional geometrical representation of beds is presented and used for numerical simulations to investigate spatial effects. Based on a freely available open-source game physics engine library (BULLET), beds of arbitrary-sized pellets can be generated and transformed to CFD-usable geometry. In CFD-software (ANSYS CFX registered) a transient diffusive transport equation with time-dependent inlet boundary conditions is solved. Three different pellet diameters were investigated with 1e18 molecules per pulse, which is higher than the limit from the theoretical calculation. Spatial and temporal distributions of transported species show regions inside the reactor, where non-Knudsen conditions exist. From this results, the distance from inlet can be calculated where the theoretical pressure limit (Knudsen number equals 2) is obtained, i.e., from this point to the end of the reactor Knudsen regime can be assumed. Due to linear dependency of pressure and concentration (assuming ideal
International Nuclear Information System (INIS)
Kolosov, S.I.; Punegov, V.I.
2005-01-01
Two independent methods for calculation of the rocking curves for laterally bounded crystals are developed. Numerical simulation of diffraction for crystals of different sizes is performed. The results obtained using the dynamical theory of diffraction are compared to those obtained in the kinematic approximation
International Nuclear Information System (INIS)
Barnard, J.J.; Ahle, L.E.; Baca, D.; Bangerter, R.O.; Bieniosek, F.M.; Celata, C.M.; Chacon-Golcher, E.; Davidson, R.C.; Faltens, A.; Friedman, A.; Franks, R.M.; Grote, D.P.; Haber, I.; Henestroza, E.; Hoon, M.J.L. de; Kaganovich, I.; Karpenko, V.P.; Kishek, R.A.; Kwan, J.W.; Lee, E.P.; Logan, B.G.; Lund, S.M.; Meier, W.R.; Molvik, A.W.; Olson, C.; Prost, L.R.; Qin, H.; Rose, D.; Sabbi, G.-L.; Sangster, T.C.; Seidl, P.A.; Sharp, W.M.; Shuman, D.; Vay, J.-L.; Waldron, W.L.; Welch, D.; Yu, S.S.
2001-01-01
The promise of inertial fusion energy driven by heavy ion beams requires the development of accelerators that produce ion currents (∼100's Amperes/beam) and ion energies (∼1-10 GeV) that have not been achieved simultaneously in any existing accelerator. The high currents imply high generalized perveances, large tune depressions, and high space charge potentials of the beam center relative to the beam pipe. Many of the scientific issues associated with ion beams of high perveance and large tune depression have been addressed over the last two decades on scaled experiments at Lawrence Berkeley and Lawrence Livermore National Laboratories, the University of Maryland, and elsewhere. The additional requirement of high space charge potential (or equivalently high line charge density) gives rise to effects (particularly the role of electrons in beam transport) which must be understood before proceeding to a large scale accelerator. The first phase of a new series of experiments in Heavy Ion Fusion Virtual National Laboratory (HIF VNL), the High Current Experiments (HCX), is now being constructed at LBNL. The mission of the HCX will be to transport beams with driver line charge density so as to investigate the physics of this regime, including constraints on the maximum radial filling factor of the beam through the pipe. This factor is important for determining both cost and reliability of a driver scale accelerator. The HCX will provide data for design of the next steps in the sequence of experiments leading to an inertial fusion energy power plant. The focus of the program after the HCX will be on integration of all of the manipulations required for a driver. In the near term following HCX, an Integrated Beam Experiment (IBX) of the same general scale as the HCX is envisioned. The step which bridges the gap between the IBX and an engineering test facility for fusion has been designated the Integrated Research Experiment (IRE). The IRE (like the IBX) will provide an
GumTree-An integrated scientific experiment environment
International Nuclear Information System (INIS)
Lam, Tony; Hauser, Nick; Goetz, Andy; Hathaway, Paul; Franceschini, Fredi; Rayner, Hugh; Zhang, Lidia
2006-01-01
GumTree is an open source and multi-platform graphical user interface for performing neutron scattering and X-ray experiments. It handles the complete experiment life cycle from instrument calibration, data acquisition, and real time data analysis to results publication. The aim of the GumTree Project is to create a highly Integrated Scientific Experiment Environment (ISEE), allowing interconnectivity and data sharing between different distributed components such as motors, detectors, user proposal database and data analysis server. GumTree is being adapted to several instrument control server systems such as TANGO, EPICS and SICS, providing an easy-to-use front-end for users and simple-to-extend model for software developers. The design of GumTree is aimed to be reusable and configurable for any scientific instrument. GumTree will be adapted to six neutron beam instruments for the OPAL reactor at ANSTO. Other European institutes including ESRF, ILL and PSI have shown interest in using GumTree as their workbench for instrument control and data analysis
GumTree - An Integrated Scientific Experiment Environment
International Nuclear Information System (INIS)
Lam, Tony; Hauser, Nick; Hathaway, Paul; Franceschini, Fredi; Rayner, Hugh; Zhang, Lidia; Goetz, Andy
2005-01-01
Full text: GumTree is an open source and multi-platform graphical user interface for performing neutron scattering and X-ray experiments. It handles the complete experiment life cycle from instrument calibration, data acquisition, and real time data analysis to results publication. The aim of the GumTree Project is to create a highly Integrated Scientific Experiment Environment (ISEE), allowing interconnectivity and data sharing between different distributed components such as motors, detectors, user proposal database and data analysis server. GumTree is being adapted to several instrument control server systems such as TANGO, EPICS and SICS, providing an easy-to-use front-end for users and simple-to-extend model for software developers. The design of GumTree is aimed to be reusable and configurable for any scientific instrument. GumTree will be adapted to six neutron beam instruments for the OPAL reactor at ANSTO. Other European institutes including ESRF, ILL and PSI have shown interest in using GumTree as their workbench for instrument control and data analysis. (authors)
Numerical calculation of a class of highly oscillatory integrals with the Mathieu function
International Nuclear Information System (INIS)
Long Yongxing
1992-01-01
The author describes a method for computing highly oscillatory integrals with the Mathieu function. The practice proves that not only the results are highly satisfactory, but also the method is time-saving
Experimental and numerical study of electrical crosstalk in photonic integrated circuits
Yao, W.; Gilardi, G.; Calabretta, N.; Smit, M.K.; Wale, M.J.
2015-01-01
This paper presents measurement results on electrical crosstalk between interconnect lines and electro-optical phaseshifters in photonic integrated circuits. The results indicate that overall crosstalk originates from radiative and substrate coupling between lines and from shared ground connections.
Integral abutment bridges under thermal loading : numerical simulations and parametric study.
2016-06-01
Integral abutment bridges (IABs) have become of interest due to their decreased construction and maintenance costs in : comparison to conventional jointed bridges. Most prior IAB research was related to substructure behavior, and, as a result, most :...
International Nuclear Information System (INIS)
Jimenez, J.C.
2009-06-01
Local Linearization (LL) methods conform a class of one-step explicit integrators for ODEs derived from the following primary and common strategy: the vector field of the differential equation is locally (piecewise) approximated through a first-order Taylor expansion at each time step, thus obtaining successive linear equations that are explicitly integrated. Hereafter, the LL approach may include some additional strategies to improve that basic affine approximation. Theoretical and practical results have shown that the LL integrators have a number of convenient properties. These include arbitrary order of convergence, A-stability, linearization preserving, regularity under quite general conditions, preservation of the dynamics of the exact solution around hyperbolic equilibrium points and periodic orbits, integration of stiff and high-dimensional equations, low computational cost, and others. In this paper, a review of the LL methods and their properties is presented. (author)
CSIR Research Space (South Africa)
Long, CS
2009-01-01
Full Text Available The effects of selected planar finite element formulations, and their associated integration schemes, on the stiffness of a checkerboard material layout are investigated. Standard 4-node bilinear elements, 8- and 9-node quadratic elements, as well...
ICM: an Integrated Compartment Method for numerically solving partial differential equations
Energy Technology Data Exchange (ETDEWEB)
Yeh, G.T.
1981-05-01
An integrated compartment method (ICM) is proposed to construct a set of algebraic equations from a system of partial differential equations. The ICM combines the utility of integral formulation of finite element approach, the simplicity of interpolation of finite difference approximation, and the flexibility of compartment analyses. The integral formulation eases the treatment of boundary conditions, in particular, the Neumann-type boundary conditions. The simplicity of interpolation provides great economy in computation. The flexibility of discretization with irregular compartments of various shapes and sizes offers advantages in resolving complex boundaries enclosing compound regions of interest. The basic procedures of ICM are first to discretize the region of interest into compartments, then to apply three integral theorems of vectors to transform the volume integral to the surface integral, and finally to use interpolation to relate the interfacial values in terms of compartment values to close the system. The Navier-Stokes equations are used as an example of how to derive the corresponding ICM alogrithm for a given set of partial differential equations. Because of the structure of the algorithm, the basic computer program remains the same for cases in one-, two-, or three-dimensional problems.
Development of a data bank system for LWR integral experiment
International Nuclear Information System (INIS)
Naito, Yoshitaka; Aoyagi, Hideo
1983-01-01
A data bank system for LWR integral experiment has been developed for the purpose of alleviating various efforts associated with the verification of computer codes. The final aim of this system is such that the imput data for the code to be verified can be easily obtained, and the results of calculation can be obtained in the form of the comparison with measurement. Geometry and material composition as well as measured data are stored in the data bank. This data bank system is composed of four sub-programs; (1) registration program, (2) information retrieval program, (3) maintenance program, and (4) figure representation program. In this report, the structure of this data bank system and how to use the system are explained. An example of the use of this system is also included. (Aoki, K.)
Dealing with scientific integrity issues: the Spanish experience.
Puigdomènech, Pere
2014-02-01
Integrity has been an important matter of concern for the scientific community as it affects the basis of its activities. Most countries having a significant scientific activity have dealt with this problem by different means, including drafting specific legal or soft law regulations and the appointment of stable or ad hoc committees that take care of these questions. This has also been the case in Spain. After the period of transition between dictatorship to a democratic regime, and, particularly, after the entrance in the European Union, scientific activity has increased in the country. As it could be expected, problems of misconduct have appeared and different institutions have been dealing with these matters. One of the best examples is that of Consejo Superior de Investigaciones Cientificas (CSIC), the largest institution devoted to scientific research belonging to the Spanish Government. The experience of the CSIC’s Ethics Committee in dealing with conflicts related to scientific practices is discussed here.
International Nuclear Information System (INIS)
Tong, S.S.; Powell, D.; Goel, S.
1992-02-01
A new software system called Engineous combines artificial intelligence and numerical methods for the design and optimization of complex aerospace systems. Engineous combines the advanced computational techniques of genetic algorithms, expert systems, and object-oriented programming with the conventional methods of numerical optimization and simulated annealing to create a design optimization environment that can be applied to computational models in various disciplines. Engineous has produced designs with higher predicted performance gains that current manual design processes - on average a 10-to-1 reduction of turnaround time - and has yielded new insights into product design. It has been applied to the aerodynamic preliminary design of an aircraft engine turbine, concurrent aerodynamic and mechanical preliminary design of an aircraft engine turbine blade and disk, a space superconductor generator, a satellite power converter, and a nuclear-powered satellite reactor and shield. 23 refs
Experience with building integrated solar collectors; Erfaring med bygningsintegrerte solfangere
Energy Technology Data Exchange (ETDEWEB)
Simonsen, Ingeborg; Time, Berit; Andresen, Inger
2011-07-01
The main objective of the research 'Zero Emission Buildings' ZEB is to develop products and solutions that provide buildings with zero greenhouse gas emissions associated with the production, operation and disposal. Can we make this happen must the building produce more energy than it needs to compensate for greenhouse gas emissions from the production of materials and the actual construction.To build up knowledge on experience with building integrated solar collectors in Norway, we have in this study made interviews with suppliers and manufacturers of solar collectors and some building owners. Since the focus is on climate shell, we have limited the study to include solar collectors to replace a part of the cladding or roofing. Construction upstairs roofing, outside facade or freestanding rack is not considered as building integrated in this context. The providers we have been in contact with appeals to slightly different parts of the market. This is reflected in the product's development, assembly and approach to the calculation of energy delivery. Overall, providers may offer a range of products suitable for both the professional and skilled carpenter, the interested 'man in the street' . The feedback we have received shows generally good experiences with the product and the installation. Because of the preliminary short operating periods of the investigated plants we have little data on energy supply from these plants. In summary, we can say that the knowledge and the products are available and it is up to use to use them.(Author)
Students' integration of multiple representations in a titration experiment
Kunze, Nicole M.
A complete understanding of a chemical concept is dependent upon a student's ability to understand the microscopic or particulate nature of the phenomenon and integrate the microscopic, symbolic, and macroscopic representations of the phenomenon. Acid-base chemistry is a general chemistry topic requiring students to understand the topics of chemical reactions, solutions, and equilibrium presented earlier in the course. In this study, twenty-five student volunteers from a second semester general chemistry course completed two interviews. The first interview was completed prior to any classroom instruction on acids and bases. The second interview took place after classroom instruction, a prelab activity consisting of a titration calculation worksheet, a titration computer simulation, or a microscopic level animation of a titration, and two microcomputer-based laboratory (MBL) titration experiments. During the interviews, participants were asked to define and describe acid-base concepts and in the second interview they also drew the microscopic representations of four stages in an acid-base titration. An analysis of the data showed that participants had integrated the three representations of an acid-base titration to varying degrees. While some participants showed complete understanding of acids, bases, titrations, and solution chemistry, other participants showed several alternative conceptions concerning strong acid and base dissociation, the formation of titration products, and the dissociation of soluble salts. Before instruction, participants' definitions of acid, base, and pH were brief and consisted of descriptive terms. After instruction, the definitions were more scientific and reflected the definitions presented during classroom instruction.
Saudi Aramco experience towards establishing Pipelines Integrity Management Systems (PIMS)
Energy Technology Data Exchange (ETDEWEB)
AlAhmari, Saad A. [Saudi Aramco, Dhahran (Saudi Arabia)
2009-12-19
Saudi Aramco pipelines network transports hydrocarbons to export terminals, processing plants and domestic users. This network faced several safety and operational-related challenges that require having a more effective Pipelines Integrity Management System (PIMS). Therefore Saudi Aramco decided to develop its PIMS on the basis of geographical information system (GIS) support through different phases, i.e., establishing the integrity management framework, risk calculation approach, conducting a gap analysis toward the envisioned PIMS, establishing the required scope of work, screening the PIMS applications market, and selecting suitable tools that satisfy expected deliverables, and implement PIMS applications. Saudi Aramco expects great benefits from implementing PIMS, e.g., enhancing safety, enhancing pipeline network robustness, optimizing inspection and maintenance expenditures, and facilitating pipeline management and the decision-making process. Saudi Aramco's new experience in adopting PIMS includes many challenges and lessons-learned associated with all of the PIMS development phases. These challenges include performing the gap analysis, conducting QA/QC sensitivity analysis for the acquired data, establishing the scope of work, selecting the appropriate applications and implementing PIMS. (author)
Saudi Aramco experience towards establishing Pipelines Integrity Management System (PIMS)
Energy Technology Data Exchange (ETDEWEB)
Al-Ahmari, Saad A. [Saudi Aramco, Dhahran (Saudi Arabia)
2009-07-01
Saudi Aramco pipelines network transports hydrocarbons to export terminals, processing plants and domestic users. This network faced several safety and operational-related challenges that require having a more effective Pipelines Integrity Management System (PIMS). Therefore Saudi Aramco decided to develop its PIMS on the basis of geographical information system (GIS) support through different phases, i.e., establishing the integrity management framework, risk calculation approach, conducting a gap analysis toward the envisioned PIMS, establishing the required scope of work, screening the PIMS applications market, and selecting suitable tools that satisfy expected deliverables, and implement PIMS applications. Saudi Aramco expects great benefits from implementing PIMS, e.g., enhancing safety, enhancing pipeline network robustness, optimizing inspection and maintenance expenditures, and facilitating pipeline management and the decision-making process. Saudi Aramco's new experience in adopting PIMS includes many challenges and lessons-learned associated with all of the PIMS development phases. These challenges include performing the gap analysis, conducting QA/QC sensitivity analysis for the acquired data, establishing the scope of work, selecting the appropriate applications and implementing PIMS. (author)
Nurse practitioner integration: Qualitative experiences of the change management process.
Lowe, Grainne; Plummer, Virginia; Boyd, Leanne
2018-04-30
The aim of this qualitative research was to explore perceptions of organisational change related to the integration of nurse practitioners from key nursing stakeholders. The ongoing delivery of effective and efficient patient services is reliant upon the development and sustainability of nurse practitioner roles. Examination of the factors contributing to the underutilization of nurse practitioner roles is crucial to inform future management policies. A change management theory is used to reveal the complexity involved. Qualitative interviews were undertaken using a purposive sampling strategy of key stakeholders. Thematic analysis was undertaken and key themes were correlated to the theoretical framework. The results confirm the benefits of nurse practitioner roles, but suggest organisational structures and embedded professional cultures present barriers to full role optimization. Complicated policy processes are creating barriers to the integration of nurse practitioner roles. The findings increase understanding of the links between strategic planning, human resource management, professional and organisational cultures, governance and politics in change management. Effective leadership drives the change process through the ability to align key components necessary for success. Sustainability of nurse practitioners relies on recognition of their full potential in the health care team. The results of this study highlight the importance of management and leadership in the promotion of advanced nursing skills and experience to better meet patient outcomes. The findings reinforce the potential of nurse practitioners to deliver patient centred, timely and efficient health care. © 2018 John Wiley & Sons Ltd.
From Differentiation to Concretisation: Integrative Experiments in Sustainable Architecture
Directory of Open Access Journals (Sweden)
Graham Farmer
2017-12-01
Full Text Available It is widely recognised that the achievement of a sustainable built environment requires holistic design practices and approaches that are capable of balancing the varied, and often conflicting, demands of environmental, social and economic concerns. However, academics and practitioners have recently highlighted, and expressed concerns about the knowledge gap that currently exists within environmental policy, research and practice between understandings of the technical performance of buildings and their social meaning and relevance. This paper acknowledges these concerns and is developed from the author’s own direct experiences of practice-led research and active participation in design-build projects. It argues for a theoretically-informed and socially-engaged approach to built environment research, pedagogy and practice that seeks to encourage an integrative understanding of the design, realisation and use of sustainable architecture. The paper draws on the Philosophy of Technology and in particular the work of Andrew Feenberg to analyse the buildings and to propose an integrated and inclusive framework for understanding sustainable design that acknowledges not just what the built environment does, but also what it means. It also suggests that what a building means also informs what it can do, and for whom. Although the technical and social dimensions of design can be interpreted as distinct practices and are often institutionally separated, this paper argues that the realisation of sustainable design must seek a conscious interaction and interchange between these two differentiated dimensions.
International Nuclear Information System (INIS)
Krauss, C.; Graeber, B.; Lange, M.; Focken, U.
2006-01-01
This work describes the integration of 18 GW of wind power into the German energy market. The focus lies on reporting practical experiences concerning the use of wind energy in Germany within the framework of the renewable energy act (EEG) and the immediate exchange of wind power between the four German grid control areas. Due to the EEG the demand for monitoring the current energy production of wind farms and for short-term predictions of wind power has significantly increased and opened a broader market for these services. In particular for trading on the intraday market ultra short term predictions in the time frame of 1 to 10 hours require different approaches than usual dayahead predictions because the large numerical meteorological models are not sufficiently optimized for very short time horizons. It is shown that for this range a combination of a statistical and a deterministic model leads to significant improvements and stable results as it unites the characteristics of the current wind power production with the synoptic-scale meteorological situation. The possible concepts of balancing the remaining differences between predicted and actual wind power generation are discussed. As wind power prediction errors and load forecasting errors are uncorrelated, benefits can arise from a combined balancing. Finally practical experiences with wind power fluctuations and large forecast errors are presented.
Lieng, M H; Corti, G; Talanov, V
2010-01-01
We consider the formation of machine background induced by proton losses in the long straight section of the LHCb experiment at LHC. Both sources showering from the tertiary collimators located in the LHCb insertion region as well as local beam-gas interaction are taken into account. We present the procedure for, and results of, numerical studies of such background for various conditions. Additionally expected impact and on the experiment and signal characteristics are discussed.
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)
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.
Energy Technology Data Exchange (ETDEWEB)
Kim, Hyung Joon [School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Kyung Hoon, E-mail: kimkh@khu.ac.kr [Department of Mechanical Engineering, Kyung Hee University, Seochun 1, Yongin, Gyeonggi 446-701 (Korea, Republic of)
2016-05-15
Highlights: • Wall-thinning erosion of pipelines in plants leads to fatal accidents unexpectedly. • Flow Acceleration Corrosion (FAC) is a main reason of wall-thinning. • For industrial safety, it is necessary to verify the tendency of FAC. • We focused on local wall thinning by FAC with intuitional visualization experiment and numerical analysis in elbow pipe.
International Nuclear Information System (INIS)
Anon.
1975-01-01
Some recommendations for the design of laboratory and field studies in marine radioecology are formulated. The difficulties concerning the comparability of various experimental methods used to measure the fluxes of radionuclides through marine organisms and ecosystems, and also the use of laboratory results to make predictions for the natural environment are discussed. Three working groups were established during the panel meeting, to consider laboratory experiments, field studies, and the design and execution of integrated laboratory and field studies respectively. A number of supporting papers dealing with marine radioecological experiments were presented
International Nuclear Information System (INIS)
Aviles, B.N.; Sutton, T.M.; Kelly, D.J. III.
1991-09-01
A generalized Runge-Kutta method has been employed in the numerical integration of the stiff space-time diffusion equations. The method is fourth-order accurate, using an embedded third-order solution to arrive at an estimate of the truncation error for automatic timestep control. The efficiency of the Runge-Kutta method is enhanced by a block-factorization technique that exploits the sparse structure of the matrix system resulting from the space and energy discretized form of the time-dependent neutron diffusion equations. Preliminary numerical evaluation using a one-dimensional finite difference code shows the sparse matrix implementation of the generalized Runge-Kutta method to be highly accurate and efficient when compared to an optimized iterative theta method. 12 refs., 5 figs., 4 tabs
Caffo, Michele; Czyż, Henryk; Gunia, Michał; Remiddi, Ettore
2009-03-01
We present the program BOKASUN for fast and precise evaluation of the Master Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the internal masses and the external four-momentum. We use a combination of two methods: a Bernoulli accelerated series expansion and a Runge-Kutta numerical solution of a system of linear differential equations. Program summaryProgram title: BOKASUN Catalogue identifier: AECG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECG_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.: 9404 No. of bytes in distributed program, including test data, etc.: 104 123 Distribution format: tar.gz Programming language: FORTRAN77 Computer: Any computer with a Fortran compiler accepting FORTRAN77 standard. Tested on various PC's with LINUX Operating system: LINUX RAM: 120 kbytes Classification: 4.4 Nature of problem: Any integral arising in the evaluation of the two-loop sunrise Feynman diagram can be expressed in terms of a given set of Master Integrals, which should be calculated numerically. The program provides a fast and precise evaluation method of the Master Integrals for arbitrary (but not vanishing) masses and arbitrary value of the external momentum. Solution method: The integrals depend on three internal masses and the external momentum squared p. The method is a combination of an accelerated expansion in 1/p in its (pretty large!) region of fast convergence and of a Runge-Kutta numerical solution of a system of linear differential equations. Running time: To obtain 4 Master Integrals on PC with 2 GHz processor it takes 3 μs for series expansion with pre-calculated coefficients, 80 μs for series expansion without pre-calculated coefficients, from a few seconds up to a few minutes for Runge-Kutta method (depending
Physics in Design : Real-time Numerical Simulation Integrated into the CAD Environment
Zwier, Marijn P.; Wits, Wessel W.
2017-01-01
As today's markets are more susceptible to rapid changes and involve global players, a short time to market is required to keep a competitive edge. Concurrently, products are integrating an increasing number of functions and technologies, thus becoming progressively complex. Therefore, efficient and
Lee, Jonghyun; SanSoucie, Michael P.
2017-08-01
Materials research is being conducted using an electromagnetic levitator installed in the International Space Station. Various metallic alloys were tested to elucidate unknown links among the structures, processes, and properties. To accomplish the mission of these space experiments, several ground-based activities have been carried out. This article presents some of our ground-based supporting experiments and numerical modeling efforts. Mass evaporation of Fe50Co50, one of flight compositions, was predicted numerically and validated by the tests using an electrostatic levitator (ESL). The density of various compositions within the Fe-Co system was measured with ESL. These results are being served as reference data for the space experiments. The convection inside a electromagnetically-levitated droplet was also modeled to predict the flow status, shear rate, and convection velocity under various process parameters, which is essential information for designing and analyzing the space experiments of some flight compositions influenced by convection.
Rößler, Thomas; Stein, Olaf; Heng, Yi; Baumeister, Paul; Hoffmann, Lars
2018-02-01
The accuracy of trajectory calculations performed by Lagrangian particle dispersion models (LPDMs) depends on various factors. The optimization of numerical integration schemes used to solve the trajectory equation helps to maximize the computational efficiency of large-scale LPDM simulations. We analyzed global truncation errors of six explicit integration schemes of the Runge-Kutta family, which we implemented in the Massive-Parallel Trajectory Calculations (MPTRAC) advection module. The simulations were driven by wind fields from operational analysis and forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) at T1279L137 spatial resolution and 3 h temporal sampling. We defined separate test cases for 15 distinct regions of the atmosphere, covering the polar regions, the midlatitudes, and the tropics in the free troposphere, in the upper troposphere and lower stratosphere (UT/LS) region, and in the middle stratosphere. In total, more than 5000 different transport simulations were performed, covering the months of January, April, July, and October for the years 2014 and 2015. We quantified the accuracy of the trajectories by calculating transport deviations with respect to reference simulations using a fourth-order Runge-Kutta integration scheme with a sufficiently fine time step. Transport deviations were assessed with respect to error limits based on turbulent diffusion. Independent of the numerical scheme, the global truncation errors vary significantly between the different regions. Horizontal transport deviations in the stratosphere are typically an order of magnitude smaller compared with the free troposphere. We found that the truncation errors of the six numerical schemes fall into three distinct groups, which mostly depend on the numerical order of the scheme. Schemes of the same order differ little in accuracy, but some methods need less computational time, which gives them an advantage in efficiency. The selection of the integration
Hu, Shaoxing; Xu, Shike; Wang, Duhu; Zhang, Aiwu
2015-11-11
Aiming at addressing the problem of high computational cost of the traditional Kalman filter in SINS/GPS, a practical optimization algorithm with offline-derivation and parallel processing methods based on the numerical characteristics of the system is presented in this paper. The algorithm exploits the sparseness and/or symmetry of matrices to simplify the computational procedure. Thus plenty of invalid operations can be avoided by offline derivation using a block matrix technique. For enhanced efficiency, a new parallel computational mechanism is established by subdividing and restructuring calculation processes after analyzing the extracted "useful" data. As a result, the algorithm saves about 90% of the CPU processing time and 66% of the memory usage needed in a classical Kalman filter. Meanwhile, the method as a numerical approach needs no precise-loss transformation/approximation of system modules and the accuracy suffers little in comparison with the filter before computational optimization. Furthermore, since no complicated matrix theories are needed, the algorithm can be easily transplanted into other modified filters as a secondary optimization method to achieve further efficiency.
Energy Technology Data Exchange (ETDEWEB)
Bammann, Douglas J.; Johnson, G. C. (University of California, Berkeley, CA); Marin, Esteban B.; Regueiro, Richard A. (University of Colorado, Boulder, CO)
2006-01-01
In this report we present the formulation of the physically-based Evolving Microstructural Model of Inelasticity (EMMI) . The specific version of the model treated here describes the plasticity and isotropic damage of metals as being currently applied to model the ductile failure process in structural components of the W80 program . The formulation of the EMMI constitutive equations is framed in the context of the large deformation kinematics of solids and the thermodynamics of internal state variables . This formulation is focused first on developing the plasticity equations in both the relaxed (unloaded) and current configurations. The equations in the current configuration, expressed in non-dimensional form, are used to devise the identification procedure for the plasticity parameters. The model is then extended to include a porosity-based isotropic damage state variable to describe the progressive deterioration of the strength and mechanical properties of metals induced by deformation . The numerical treatment of these coupled plasticity-damage constitutive equations is explained in detail. A number of examples are solved to validate the numerical implementation of the model.
Multi-Disciplinary Research Experiences Integrated with Industry –Field Experiences
Directory of Open Access Journals (Sweden)
Suzanne Lunsford
2015-10-01
Full Text Available The purpose of this environmentally inquiry-based lab was to allow the students to engage into real-world concepts that integrate industry setting (Ohio Aggregate Industrial Mineral Association with the academia setting. Our students are engaged into a field trip where mining occurs to start the problem based learning of how the heavy metals leak in the mining process. These heavy metals such as lead and indium in the groundwater are a serious concern for the environment (Environmental Protection Agency from the mining process. The field experiences at the mining process assist in building our students interest in developing sensors to detect heavy metals of concern such as lead and indium simultaneously by a unique electrochemistry technique called Square Wave Anodic Stripping Voltammetry (SWASV. The field experience assists building the students interest in real –world application and what qualities do they want the electrochemical sensor to possess to be successful for real world usage. During the field trip the students are engaged into learning novel instrumentation such as an SEM (Scanning Electron Microscope to study the working electrode sensor developed to understand the sensor surface morphology properties better as well. The integration of industry setting with academia has been a positive experience for our students that has allowed their understanding of real-world science research needs to succeed in an industrial setting of research.
Maina, Fadji Hassane; Ackerer, Philippe; Younes, Anis; Guadagnini, Alberto; Berkowitz, Brian
2017-06-07
We present a combined experimental and numerical modeling study that addresses two principal questions: (i) is any particular Eulerian-based method used to solve the classical advection-dispersion equation (ADE) clearly superior (relative to the others), in terms of yielding solutions that reproduce BTCs of the kind that are typically sampled at the outlet of a laboratory cell? and (ii) in the presence of matches of comparable quality against such BTCs, do any of these methods render different (or similar) numerical BTCs at locations within the domain? To address these questions, we obtained measurements from carefully controlled laboratory experiments, and employ them as a reference against which numerical results are benchmarked and compared. The experiments measure solute transport breakthrough curves (BTCs) through a square domain containing various configurations of coarse, medium, and fine quartz sand. The approaches to solve the ADE involve Eulerian-Lagrangian and Eulerian (finite volume, finite elements, mixed and discontinuous finite elements) numerical methods. Model calibration is not examined; permeability and porosity of each sand were determined previously through separate, standard laboratory tests, while dispersivities are assigned values proportional to mean grain size. We find that the spatial discretization of the flow field is of critical importance, due to the non-uniformity of the domain. Although simulated BTCs at the system outlet are observed to be very similar for these various numerical methods, computed local (point-wise, inside the domain) BTCs can be very different. We find that none of the numerical methods is able to fully reproduce the measured BTCs. The impact of model parameter uncertainty on the calculated BTCs is characterized through a set of numerical Monte Carlo simulations; in cases where the impact is significant, assessment of simulation matches to the experimental data can be ambiguous. Copyright © 2017 Elsevier B.V. All
International Nuclear Information System (INIS)
Mysina, N Yu; Maksimova, L A; Ryabukho, V P; Gorbatenko, B B
2015-01-01
Investigated are statistical properties of the phase difference of oscillations in speckle-fields at two points in the far-field diffraction region, with different shapes of the scatterer aperture. Statistical and spatial nonuniformity of the probability density function of the field phase difference is established. Numerical experiments show that, for the speckle-fields with an oscillating alternating-sign transverse correlation function, a significant nonuniformity of the probability density function of the phase difference in the correlation region of the field complex amplitude, with the most probable values 0 and p, is observed. A natural statistical interference experiment using Young diagrams has confirmed the results of numerical experiments. (laser applications and other topics in quantum electronics)
An Integrated Approach for the Numerical Modelling of the Spray Forming Process
DEFF Research Database (Denmark)
Hattel, Jesper; Thorborg, Jesper; Pryds, Nini
2003-01-01
In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation of the depos......In this paper, an integrated approach for modelling the entire spray forming process is presented. The basis for the analysis is a recently developed model which extents previous studies and includes the interaction between an array of droplets and the enveloping gas. The formulation...... is in fact the summation of "local" droplet size distributions along the r-axis. Furthermore, the deposition model proposed in the paper involves both the sticking efficiency of the droplets to the substrate as well as a geometrical model involving the effects of shadowing for the production of billet...
Duque, Earl P. N.; Johnson, Wayne; vanDam, C. P.; Chao, David D.; Cortes, Regina; Yee, Karen
1999-01-01
Accurate, reliable and robust numerical predictions of wind turbine rotor power remain a challenge to the wind energy industry. The literature reports various methods that compare predictions to experiments. The methods vary from Blade Element Momentum Theory (BEM), Vortex Lattice (VL), to variants of Reynolds-averaged Navier-Stokes (RaNS). The BEM and VL methods consistently show discrepancies in predicting rotor power at higher wind speeds mainly due to inadequacies with inboard stall and stall delay models. The RaNS methodologies show promise in predicting blade stall. However, inaccurate rotor vortex wake convection, boundary layer turbulence modeling and grid resolution has limited their accuracy. In addition, the inherently unsteady stalled flow conditions become computationally expensive for even the best endowed research labs. Although numerical power predictions have been compared to experiment. The availability of good wind turbine data sufficient for code validation experimental data that has been extracted from the IEA Annex XIV download site for the NREL Combined Experiment phase II and phase IV rotor. In addition, the comparisons will show data that has been further reduced into steady wind and zero yaw conditions suitable for comparisons to "steady wind" rotor power predictions. In summary, the paper will present and discuss the capabilities and limitations of the three numerical methods and make available a database of experimental data suitable to help other numerical methods practitioners validate their own work.
Energy Technology Data Exchange (ETDEWEB)
Yoon, Sang Won [Hanyang University, Seoul (Korea, Republic of)
2017-05-15
This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.
International Nuclear Information System (INIS)
Yoon, Sang Won
2017-01-01
This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.
DEFF Research Database (Denmark)
Courdent, Vianney Augustin Thomas
domains during which the IUDWS can be coupled with the electrical smart grid to optimise its energy consumption. The REV framework was used to determine which decision threshold of the EPS (i.e. number of ensemble members predicting an event) provides the highest benefit for a given situation...... in cities where space is scarce and large-scale construction work a nuisance. This the-sis focuses on flow domain predictions of IUDWS from numerical weather prediction (NWP) to select relevant control objectives for the IUDWS and develops a framework based on the relative economic value (REV) approach...... to evaluate when acting on the forecast is beneficial or not. Rainfall forecasts are extremely valuable for estimating near future storm-water-related impacts on the IUDWS. Therefore, weather radar extrapolation “nowcasts” provide valuable predictions for RTC. However, radar nowcasts are limited...
International Nuclear Information System (INIS)
Harding, D.C.; Eldred, M.S.; Witkowski, W.R.
1995-01-01
Type B radioactive material transport packages must meet strict Nuclear Regulatory Commission (NRC) regulations specified in 10 CFR 71. Type B containers include impact limiters, radiation or thermal shielding layers, and one or more containment vessels. In the past, each component was typically designed separately based on its driving constraint and the expertise of the designer. The components were subsequently assembled and the design modified iteratively until all of the design criteria were met. This approach neglects the fact that components may serve secondary purposes as well as primary ones. For example, an impact limiter's primary purpose is to act as an energy absorber and protect the contents of the package, but can also act as a heat dissipater or insulator. Designing the component to maximize its performance with respect to both objectives can be accomplished using numerical optimization techniques
Emerging opportunities in enterprise integration with open architecture computer numerical controls
Hudson, Christopher A.
1997-01-01
The shift to open-architecture machine tool computer numerical controls is providing new opportunities for metal working oriented manufacturers to streamline the entire 'art to part' process. Production cycle times, accuracy, consistency, predictability and process reliability are just some of the factors that can be improved, leading to better manufactured product at lower costs. Open architecture controllers are allowing manufacturers to apply general purpose software and hardware tools increase where previous approaches relied on proprietary and unique hardware and software. This includes DNC, SCADA, CAD, and CAM, where the increasing use of general purpose components is leading to lower cost system that are also more reliable and robust than the past proprietary approaches. In addition, a number of new opportunities exist, which in the past were likely impractical due to cost or performance constraints.
International Nuclear Information System (INIS)
Havu, V.; Blum, V.; Havu, P.; Scheffler, M.
2009-01-01
We consider the problem of developing O(N) scaling grid-based operations needed in many central operations when performing electronic structure calculations with numeric atom-centered orbitals as basis functions. We outline the overall formulation of localized algorithms, and specifically the creation of localized grid batches. The choice of the grid partitioning scheme plays an important role in the performance and memory consumption of the grid-based operations. Three different top-down partitioning methods are investigated, and compared with formally more rigorous yet much more expensive bottom-up algorithms. We show that a conceptually simple top-down grid partitioning scheme achieves essentially the same efficiency as the more rigorous bottom-up approaches.
Directory of Open Access Journals (Sweden)
Junlong Yang
2017-03-01
Full Text Available In this work, deformations and internal forces of an existing tunnel subjected to a closely overlapped shield tunneling are monitored and analyzed using a series of physical model experiments and numerical simulations. Effects of different excavation sequences and speeds are explicitly considered in the analysis. The results of the physical model experiments show that the bottom-up tunneling procedure is better than the top-down tunneling procedure. The incurred deformations and internal forces of the existing tunnel increase with the excavation speed and the range of influence areas also increase accordingly. For construction process control, real-time monitoring of the power tunnel is used. The monitoring processes feature full automation, adjustable frequency, real-time monitor and dynamic feedback, which are used to guide the construction to achieve micro-disturbance control. In accordance with the situation of crossing construction, a numerical study on the performance of power tunnel is carried out. Construction control measures are given for the undercrossing construction, which helps to accomplish the desired result and meet protection requirements of the existing tunnel structure. Finally, monitoring data and numerical results are compared, and the displacement and joint fracture change models in the power tunnel subject to the overlapped shield tunnel construction are analyzed. Keywords: Overlapped tunnel, Automatic monitoring, Micro-disturbance control
Siegler, Robert S.; Braithwaite, David W.
2016-01-01
In this review, we attempt to integrate two crucial aspects of numerical development: learning the magnitudes of individual numbers and learning arithmetic. Numerical magnitude development involves gaining increasingly precise knowledge of increasing ranges and types of numbers: from non-symbolic to small symbolic numbers, from smaller to larger…
Numerical models and experiment of air flow in a simulation box for optical wireless communications
Directory of Open Access Journals (Sweden)
Latal Jan
2016-01-01
Full Text Available In this article, the authors focused on real measurements of mechanical turbulence generated by ventilators in the simulation box for Optical Wireless Communications. The mechanical turbulences disturb the optical beam that propagates along the central axis of the simulation box. The aim of authors is to show the effect of mechanical turbulence on optical beams at different heights in the simulation box. In the Ansys Fluent, we created numerical models which were then compared with real measurements. Authors compared the real and numerical models according to statistical methods.
Numerical simulation of experimental data from planar SIS mixers with integrated tuning elements
International Nuclear Information System (INIS)
Mears, C.A.; Hu, Qing; Richards, P.L.
1988-08-01
We have used the full Tucker theory including the quantum susceptance to fit data from planar lithographed mm-wave mixers with bow tie antennas and integrated RF coupling elements. Essentially perfect fits to pumped IV curves have been obtained. The deduced imbedding admittances agree well with those independently calculated from the geometry of the antenna and matching structures. We find that the quantum susceptance is essential to the fit and thus to predictions of the mixer performance. For junctions with moderately sharp gap structures, the quantum susceptance is especially important in the production of steps with low and/or negative dynamic conductance. 15 refs., 4 figs
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.
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.
An integrated numerical model for the prediction of Gaussian and billet shapes
DEFF Research Database (Denmark)
Hattel, Jesper; Pryds, Nini; Pedersen, Trine Bjerre
2004-01-01
Separate models for the atomisation and the deposition stages were recently integrated by the authors to form a unified model describing the entire spray-forming process. In the present paper, the focus is on describing the shape of the deposited material during the spray-forming process, obtained...... by this model. After a short review of the models and their coupling, the important factors which influence the resulting shape, i.e. Gaussian or billet, are addressed. The key parameters, which are utilized to predict the geometry and dimension of the deposited material, are the sticking efficiency...
Ikeguchi, Mitsunori; Doi, Junta
1995-09-01
The Ornstein-Zernike integral equation (OZ equation) has been used to evaluate the distribution function of solvents around solutes, but its numerical solution is difficult for molecules with a complicated shape. This paper proposes a numerical method to directly solve the OZ equation by introducing the 3D lattice. The method employs no approximation the reference interaction site model (RISM) equation employed. The method enables one to obtain the spatial distribution of spherical solvents around solutes with an arbitrary shape. Numerical accuracy is sufficient when the grid-spacing is less than 0.5 Å for solvent water. The spatial water distribution around a propane molecule is demonstrated as an example of a nonspherical hydrophobic molecule using iso-value surfaces. The water model proposed by Pratt and Chandler is used. The distribution agrees with the molecular dynamics simulation. The distribution increases offshore molecular concavities. The spatial distribution of water around 5α-cholest-2-ene (C27H46) is visualized using computer graphics techniques and a similar trend is observed.
Researchers' experiences, positive and negative, in integrative landscape projects
Tress, B.; Tress, G.; Fry, G.
2005-01-01
Integrative (interdisciplinary and transdisciplinary) landscape research projects are becoming increasingly common. As a result, researchers are spending a larger proportion of their professional careers doing integrative work, participating in shifting interdisciplinary teams, and cooperating
Nuclear data and integral experiments in reactor physics
International Nuclear Information System (INIS)
Farinelli, U.
1980-01-01
The material given here broadly covers the content of the 10 lectures delivered at the Winter Course on Reactor Theory and Power Reactors, ICTP, Trieste (13 February - 10 March 1978). However, the parts that could easily be found in the current literature have been omitted and replaced with the appropriate references. The needs for reactor physics calculations, particularly as applicable to commercial reactors, are reviewed in the introduction. The relative merits and shortcomings of fundamental and semi-empirical methods are discussed. The relative importance of different nuclear data, the ways in which they can be measured or calculated, and the sources of information on measured and evaluated data are briefly reviewed. The various approaches to the condensation of nuclear data to multigroup cross sections are described. After some consideration to the sensitivity calculations and the evaluation of errors, some of the most important type of integral experiments in reactor physics are introduced, with a view to showing the main difficulties in the interpretation and utilization of their results and the most recent trends in experimentation. The conclusions try to assign some priorities in the implementation of experimental and calculational capabilities, especially for a developing country. (author)
Numerical Simulation of Fluidized Bed Gasifier for Integrated Gasification Combined Cycle
Directory of Open Access Journals (Sweden)
CHEN Ju-hui
2017-06-01
Full Text Available The overall thermal efficiency of the integrated gasification combined cycle ( IGCC has not been sufficiently improved. In order to achieve higher power generation efficiency，the advanced technology of IGCC has been developed which is on the basis of the concept of exergy recovery. IGCC systems and devices from the overall structure of opinion，this technology will generate electricity for the integration of advanced technology together，the current utilization of power generation technology and by endothermic reaction of steam in the gasifier，a gas turbine exhaust heat recovery or the solid oxide fuel cell. It is estimated that such the use of exergy recycling has the advantage of being easy to use，separating，collecting fixed CO2，making it very attractive，and can increase the overall efficiency by 10% or more. The characteristics of fluidized bed gasifier，one of the core equipment of the IGCC system，and its effect on the whole system were studied.
International Nuclear Information System (INIS)
Laura, P.A.A.
1978-01-01
This paper compares analytical and finite element results for an unsteady heat-conduction problem in simply and doubly connected plates of regular polygonal shape. A numerical solution is obtained by means of the powerful finite element method and the results are shown to agree with an approximate conformal mapping-variational technique previously developed by the first author and coworkers. (Auth.)
DEFF Research Database (Denmark)
de Souza Reboucas, Geraldo Francisco; Santos, Ilmar; Thomsen, Jon Juel
2017-01-01
The frequency response of a single degree of freedom vibro-impact oscillator is analyzed using Harmonic Linearization, Averaging and Numeric Simulation, considering three different impact force models: one given by a piecewise-linear function (Kelvin-Voigt model), another by a high-order power...
Singha, Kamini; Loheide, Steven P., II
2011-01-01
Visualising subsurface processes in hydrogeology and building intuition for how these processes are controlled by changes in forcing is hard for many undergraduate students. While numerical modelling is one way to help undergraduate students explore outcomes of multiple scenarios, many codes are not user-friendly with respect to defining domains,…
Validating the BISON fuel performance code to integral LWR experiments
Energy Technology Data Exchange (ETDEWEB)
Williamson, R.L., E-mail: Richard.Williamson@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Gamble, K.A., E-mail: Kyle.Gamble@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Perez, D.M., E-mail: Danielle.Perez@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Novascone, S.R., E-mail: Stephen.Novascone@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Pastore, G., E-mail: Giovanni.Pastore@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Gardner, R.J., E-mail: Russell.Gardner@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Hales, J.D., E-mail: Jason.Hales@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Liu, W., E-mail: Wenfeng.Liu@anatech.com [ANATECH Corporation, 5435 Oberlin Dr., San Diego, CA 92121 (United States); Mai, A., E-mail: Anh.Mai@anatech.com [ANATECH Corporation, 5435 Oberlin Dr., San Diego, CA 92121 (United States)
2016-05-15
Highlights: • The BISON multidimensional fuel performance code is being validated to integral LWR experiments. • Code and solution verification are necessary prerequisites to validation. • Fuel centerline temperature comparisons through all phases of fuel life are very reasonable. • Accuracy in predicting fission gas release is consistent with state-of-the-art modeling and the involved uncertainties. • Rod diameter comparisons are not satisfactory and further investigation is underway. - Abstract: BISON is a modern finite element-based nuclear fuel performance code that has been under development at Idaho National Laboratory (INL) since 2009. The code is applicable to both steady and transient fuel behavior and has been used to analyze a variety of fuel forms in 1D spherical, 2D axisymmetric, or 3D geometries. Code validation is underway and is the subject of this study. A brief overview of BISON's computational framework, governing equations, and general material and behavioral models is provided. BISON code and solution verification procedures are described, followed by a summary of the experimental data used to date for validation of Light Water Reactor (LWR) fuel. Validation comparisons focus on fuel centerline temperature, fission gas release, and rod diameter both before and following fuel-clad mechanical contact. Comparisons for 35 LWR rods are consolidated to provide an overall view of how the code is predicting physical behavior, with a few select validation cases discussed in greater detail. Results demonstrate that (1) fuel centerline temperature comparisons through all phases of fuel life are very reasonable with deviations between predictions and experimental data within ±10% for early life through high burnup fuel and only slightly out of these bounds for power ramp experiments, (2) accuracy in predicting fission gas release appears to be consistent with state-of-the-art modeling and with the involved uncertainties and (3) comparison
Integrated numerical design of an innovative Lower Hybrid launcher for Alcator C-Mod
International Nuclear Information System (INIS)
Meneghini, O.; Shiraiwa, S.; Beck, W.; Irby, J.; Koert, P.; Parker, R. R.; Viera, R.; Wukitch, S.; Wilson, J.
2009-01-01
The new Alcator C-Mod LHCD system (LH2) is based on the concept of a four way splitter [1] which evenly splits the RF power among the four waveguides that compose one of the 16 columns of the LH grill. In this work several simulation tools have been used to study the LH2 coupling performance and the launched spectra when facing a plasma, numerically verifying the effectiveness of the four way splitter concept and further improving its design. The TOPLHA code has been used for modeling reflections at the antenna/plasma interface. TOPLHA results have been then coupled to the commercial code CST Microwave Studio to efficiently optimize the four way splitter geometry for several plasma scenarios. Subsequently, the COMSOL Multiphysics code has been used to self consistently take into account the electromagnetic-thermal-structural interactions. This comprehensive and predictive analysis has proven to be very valuable for understanding the behavior of the system when facing the plasma and has profoundly influenced several design choices of the LH2. According to the simulations, the final design ensures even poloidal power splitting for a wide range of plasma parameters, which ultimately results in an improvement of the wave coupling and an increased maximum operating power.
Directory of Open Access Journals (Sweden)
Sheam-Chyun Lin
2014-02-01
Full Text Available Since the inlet and outlet of hidden ceiling fan are almost located at the same Plane; thus, an improper housing may cause inhale-return phenomenon which significantly affects its power consumption and performance. In this study, a comprehensive investigation by numerical and experimental techniques was used to predict and identify the flow pattern, airflow rate, efficiency, and noise for ceiling fans with different design parameters. The results showed that the unique inhale-return phenomenon happens for an inappropriate housing. Several key parameters, such as fan guard, housing ring, inlet-to-outlet area ratio, and blockage height, are evaluated for finding out the criterion to avoid the inhale-return flow. Consequently the study finds that fan guard changes the airflow to a wider distribution with a lower velocity. A minimum blockage distance and a maximum height of ring-plate are set at 80 mm and 30 mm, respectively. Also, it is suggested that the inlet area must be bigger than the outlet area. Moreover, all the parameters show the same trend under various rotational speeds. In conclusion, this systematic investigation not only provides the fan engineer's design ability to avoid the inhale-return phenomenon, but also the predicting capability on its aerodynamic and acoustic performances.
Energy Technology Data Exchange (ETDEWEB)
Patrignani, L.; Losurdo, M.; Bruno, C. [Sapienza Univ. de Roma, Rome (Italy)
2010-09-15
Exhaust emissions from furnace burners can be reduced by premixing reactants with combustion products. This paper discussed the use of a trapped vortex combustor (TVC) as a very promising technology for gas turbines. The TVC can reduce emissions and ensure that the temperature is uniform in the exhaust products, which is a key aspect for certain types of heat treatments, such as in steel rolling mills. The TVC for gas turbines is configured to mix air, fuel and hot products at turbulent scales fine enough to render the combustion mode flameless, or close to flameless. The vortex ensures a high recirculation factor between hot combustion products and reactants, and ultimately flame stability. In this study, the TVC configuration for an existing gas turbine was numerically investigated by means of RANS and LES. According to preliminary results of the fast-flameless combustion (FFC) strategy, the proposed TVC is a suitable candidate to reduce nitrogen oxide (NOx) emissions while keeping the pressure drop below 1 per cent. Both RANS and LES show that too much fuel burns along the main duct. Better fuel splitting or a different position for the injectors may enhance combustion inside the recirculation zone. Behaviour of the main vortices showed that a more accurate design of the internal shape of the combustor is needed to prevent excessive velocity fluctuation or vortex instabilities and therefore emissions. 13 refs., 9 figs.
DEFF Research Database (Denmark)
Saraswathi, Ananthavel; Sanjeevikumar, Padmanaban; Shanmugham, Sutha
2016-01-01
Power system researches are mainly focused in enhancing the available power capacities of the existing transmission lines. But still, no prominent solutions have been made due to several factors that affect the transmission lines which include the length, aging of the cables and losses...... on generation, transmission and distribution etc. This paper exploited the integration of static synchronous compensator (STATCOM) and superconducting magnetic energy storage (SMES) which is then connected to existing power transmission line for enhancing the available power transfer capacity (ATC). STATCOMis...... power electronic voltage source converter (VSC) which is connected to the transmission system for shunt reactive power and harmonics compensation. SMES is a renowned clean energy storage technology. Feasibility of the proposed power system can control the real as well as reactive power flow...
Energy Technology Data Exchange (ETDEWEB)
Sun, Lin; Peng, Min Jun; Xia, Genglei; Lv, Xing; Li, Ren [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin (China)
2017-02-15
When an integral pressurized water reactor is operated under low power conditions, once-through steam generator group operation strategy is applied. However, group operation strategy will cause nonuniform coolant flow distribution at the core inlet and lower plenum. To help coolant flow mix more uniformly, a flow mixing chamber (FMC) has been designed. In this paper, computational fluid dynamics methods have been used to investigate the coolant distribution by the effect of FMC. Velocity and temperature characteristics under different low power conditions and optimized FMC configuration have been analyzed. The results illustrate that the FMC can help improve the nonuniform coolant temperature distribution at the core inlet effectively; at the same time, the FMC will induce more resistance in the downcomer and lower plenum.
Results of numerically solving an integral equation for a two-fermion system
International Nuclear Information System (INIS)
Skachkov, N.B.; Solov'eva, T.M.
2003-01-01
A two-particle system is described by integral equations whose kernels are dependent on the total energy of the system. Such equations can be reduced to an eigenvalue problem featuring an eigenvalue-dependent operator. This nonlinear eigenvalue problem is solved by means of an iterative procedure developed by the present authors. The energy spectra of a two-fermion system formed by particles of identical masses are obtained for two cases, that where the total spin of the system is equal to zero and that where the total spin of the system is equal to unity. The splitting of the ground-state levels of positronium and dimuonium, the frequency of the transition from the ground state of orthopositronium to its first excited state, and the probabilities of parapositronium and paradimuonium decays are computed. The results obtained in this way are found to be in good agreement with experimental data
An integrated numerical model for the prediction of Gaussian and billet shapes
International Nuclear Information System (INIS)
Hattel, J.H.; Pryds, N.H.; Pedersen, T.B.
2004-01-01
Separate models for the atomisation and the deposition stages were recently integrated by the authors to form a unified model describing the entire spray-forming process. In the present paper, the focus is on describing the shape of the deposited material during the spray-forming process, obtained by this model. After a short review of the models and their coupling, the important factors which influence the resulting shape, i.e. Gaussian or billet, are addressed. The key parameters, which are utilized to predict the geometry and dimension of the deposited material, are the sticking efficiency and the shading effect for Gaussian and billet shape, respectively. From the obtained results, the effect of these parameters on the final shape is illustrated
Evaluation of diffuse hepatic diseases by integrated image, SPECT and numerical taxonomic analysis
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, Shin
1987-02-01
In 135 patients with various hepatic diseases, cardiopulmonary circulation and hepatic accumulation of the activity were collected for 100 sec after bolus injection of 111-222 MBq (3 - 6 mci) of /sup 99m/Tc-phytate, and then integrated as a single image. Anterior, right lateral and posterior planar images, and hepatosplenic SPECT images were obtained thereafter. Lung to liver count ratio (P/L) was estimated by the integrated image. Liver volume (HV), spleen volume (SV) and liver to spleen count ratio (MHC/MSC) were calculated using the data obtained by SPECT. P/L was useful as an index of effective hepatic blood flow. MHC/MSC was closely correlated with the grade of portal hypertension. HV or SV alone shows low clinical value in discriminating liver diseases. Principal component analysis was applied to the 4 above-mentioned radinuclide data and the following 11 laboratory data ; total serum protein, serum albumine, glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), lactic dehydrogenase (LDH), alkaline phosphatase (AL-P), zink sulfateturbidity test (ZTT), thymol turbidity test (TTT), r-glutamyl transpeptidase (r-GTP), cholinesterase (Ch-E), and total bilirubin (T-Bil). These fifteen data were condensed to 5 principal components. And then cluster analysis was carried out among 135 patients. The subjects were classified in 7 small groups. In group (G) I to GIII, frequency of liver cirrhosis was high, while on the contrary in GIV to GVII, the frequency of normal cases increased gradually. From the above results, cluster analysis seemed to reflect the pathophysiological state and the grade of the disease. This method might be useful for estimation of the grade of damage in diffuse hepatic disease and a good objective evaluation method in follow-up studies. (J.P.N.).
Hu, R.; Wan, J.
2015-12-01
Wettability of reservoir minerals along pore surfaces plays a controlling role in capillary trapping of supercritical (sc) CO2 in geologic carbon sequestration. The mechanisms controlling scCO2 residual trapping are still not fully understood. We studied the effect of pore surface wettability on CO2 residual saturation at the pore-scale using engineered high pressure and high temperature micromodel (transparent pore networks) experiments and numerical modeling. Through chemical treatment of the micromodel pore surfaces, water-wet, intermediate-wet, and CO2-wet micromodels can be obtained. Both drainage and imbibition experiments were conducted at 8.5 MPa and 45 °C with controlled flow rate. Dynamic images of fluid-fluid displacement processes were recorded using a microscope with a CCD camera. Residual saturations were determined by analysis of late stage imbibition images of flow path structures. We performed direct numerical simulations of the full Navier-Stokes equations using a volume-of-fluid based finite-volume framework for the primary drainage and the followed imbibition for the micromodel experiments with different contact angles. The numerical simulations agreed well with our experimental observations. We found that more scCO2 can be trapped within the CO2-wet micromodel whereas lower residual scCO2 saturation occurred within the water-wet micromodels in both our experiments and the numerical simulations. These results provide direct and consistent evidence of the effect of wettability, and have important implications for scCO2 trapping in geologic carbon sequestration.
WEC-SIM Phase 1 Validation Testing -- Numerical Modeling of Experiments: Preprint
Energy Technology Data Exchange (ETDEWEB)
Ruehl, Kelley; Michelen, Carlos; Bosma, Bret; Yu, Yi-Hsiang
2016-08-01
The Wave Energy Converter Simulator (WEC-Sim) is an open-source code jointly developed by Sandia National Laboratories and the National Renewable Energy Laboratory. It is used to model wave energy converters subjected to operational and extreme waves. In order for the WEC-Sim code to be beneficial to the wave energy community, code verification and physical model validation is necessary. This paper describes numerical modeling of the wave tank testing for the 1:33-scale experimental testing of the floating oscillating surge wave energy converter. The comparison between WEC-Sim and the Phase 1 experimental data set serves as code validation. This paper is a follow-up to the WEC-Sim paper on experimental testing, and describes the WEC-Sim numerical simulations for the floating oscillating surge wave energy converter.
The integrated circuit IC EMP transient state disturbance effect experiment method investigates
International Nuclear Information System (INIS)
Li Xiaowei
2004-01-01
Transient state disturbance characteristic study on the integrated circuit, IC, need from its coupling path outset. Through cable (aerial) coupling, EMP converts to an pulse current voltage and results in the impact to the integrated circuit I/O orifice passing the cable. Aiming at the armament system construction feature, EMP effect to the integrated circuit, IC inside the system is analyzed. The integrated circuit, IC EMP effect experiment current injection method is investigated and a few experiments method is given. (authors)
Integrating Renewable Generation into Grid Operations: Four International Experiences
Energy Technology Data Exchange (ETDEWEB)
Weimar, Mark R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mylrea, Michael E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levin, Todd [Argonne National Lab. (ANL), Argonne, IL (United States); Botterud, Audun [Argonne National Lab. (ANL), Argonne, IL (United States); O' Shaughnessy, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States)
2016-04-22
International experiences with power sector restructuring and the resultant impacts on bulk power grid operations and planning may provide insight into policy questions for the evolving United States power grid as resource mixes are changing in response to fuel prices, an aging generation fleet and to meet climate goals. Australia, Germany, Japan and the UK were selected to represent a range in the level and attributes of electricity industry liberalization in order to draw comparisons across a variety of regions in the United States such as California, ERCOT, the Southwest Power Pool and the Southeast Reliability Region. The study draws conclusions through a literature review of the four case study countries with regards to the changing resource mix and the electricity industry sector structure and their impact on grid operations and planning. This paper derives lessons learned and synthesizes implications for the United States based on answers to the above questions and the challenges faced by the four selected countries. Each country was examined to determine the challenges to their bulk power sector based on their changing resource mix, market structure, policies driving the changing resource mix, and policies driving restructuring. Each countries’ approach to solving those changes was examined, as well as how each country’s market structure either exacerbated or mitigated the approaches to solving the challenges to their bulk power grid operations and planning. All countries’ policies encourage renewable energy generation. One significant finding included the low- to zero-marginal cost of intermittent renewables and its potential negative impact on long-term resource adequacy. No dominant solution has emerged although a capacity market was introduced in the UK and is being contemplated in Japan. Germany has proposed the Energy Market 2.0 to encourage flexible generation investment. The grid operator in Australia proposed several approaches to maintaining
International Nuclear Information System (INIS)
Kalogiratou, Z.; Monovasilis, Th.; Psihoyios, G.; Simos, T.E.
2014-01-01
In this work we review single step methods of the Runge–Kutta type with special properties. Among them are methods specially tuned to integrate problems that exhibit a pronounced oscillatory character and such problems arise often in celestial mechanics and quantum mechanics. Symplectic methods, exponentially and trigonometrically fitted methods, minimum phase-lag and phase-fitted methods are presented. These are Runge–Kutta, Runge–Kutta–Nyström and Partitioned Runge–Kutta methods. The theory of constructing such methods is given as well as several specific methods. In order to present the performance of the methods we have tested 58 methods from all categories. We consider the two dimensional harmonic oscillator, the two body problem, the pendulum problem and the orbital problem studied by Stiefel and Bettis. Also we have tested the methods on the computation of the eigenvalues of the one dimensional time independent Schrödinger equation with the harmonic oscillator, the doubly anharmonic oscillator and the exponential potentials
Temperature Fields in Soft Tissue during LPUS Treatment: Numerical Prediction and Experiment Results
International Nuclear Information System (INIS)
Kujawska, Tamara; Wojcik, Janusz; Nowicki, Andrzej
2010-01-01
Recent research has shown that beneficial therapeutic effects in soft tissues can be induced by the low power ultrasound (LPUS). For example, increasing of cells immunity to stress (among others thermal stress) can be obtained through the enhanced heat shock proteins (Hsp) expression induced by the low intensity ultrasound. The possibility to control the Hsp expression enhancement in soft tissues in vivo stimulated by ultrasound can be the potential new therapeutic approach to the neurodegenerative diseases which utilizes the known feature of cells to increase their immunity to stresses through the Hsp expression enhancement. The controlling of the Hsp expression enhancement by adjusting of exposure level to ultrasound energy would allow to evaluate and optimize the ultrasound-mediated treatment efficiency. Ultrasonic regimes are controlled by adjusting the pulsed ultrasound waves intensity, frequency, duration, duty cycle and exposure time. Our objective was to develop the numerical model capable of predicting in space and time temperature fields induced by a circular focused transducer generating tone bursts in multilayer nonlinear attenuating media and to compare the numerically calculated results with the experimental data in vitro. The acoustic pressure field in multilayer biological media was calculated using our original numerical solver. For prediction of temperature fields the Pennes' bio-heat transfer equation was employed. Temperature field measurements in vitro were carried out in a fresh rat liver using the 15 mm diameter, 25 mm focal length and 2 MHz central frequency transducer generating tone bursts with the spatial peak temporal average acoustic intensity varied between 0.325 and 1.95 W/cm 2 , duration varied from 20 to 500 cycles at the same 20% duty cycle and the exposure time varied up to 20 minutes. The measurement data were compared with numerical simulation results obtained under experimental boundary conditions. Good agreement between the
Malamataris, Nikolaos; Liakos, Anastasios
2015-11-01
The exact value of the Reynolds number regarding the inception of separation in the flow around a circular cylinder is still a matter of research. This work connects the inception of separation with the calculation of a positive pressure gradient around the circumference of the cylinder. The hypothesis is that inception of separation occurs when the pressure gradient becomes positive around the circumference. From the most cited laboratory experiments that have dealt with that subject of inception of separation only Thom has measured the pressure gradient there at very low Reynolds numbers (up to Re=3.5). For this reason, the experimental conditions of his tunnel are simulated in a new numerical experiment. The full Navier Stokes equations in both two and three dimensions are solved with a home made code that utilizes Galerkin finite elements. In the two dimensional numerical experiment, inception of separation is observed at Re=4.3, which is the lowest Reynolds number where inception has been reported computationally. Currently, the three dimensional experiment is under way, in order to compare if there are effects of three dimensional theory of separation in the conditions of Thom's experiments.
High energy physics program: Task A, Experiment and theory; Task B, Numerical simulation
International Nuclear Information System (INIS)
1993-01-01
This report discusses research in High Energy Physics at Florida State University. Contained in this paper are: highlights of activities during the past few years; five year summary; fixed target experiments; collider experiments; SSC preparation, detector development and detector construction; computing, networking and VAX upgrade to ALPHA; and particle theory programs
Numerical simulation of the integrated solar/North Benghazi combined power plant
International Nuclear Information System (INIS)
Aldali, Y.; Morad, K.
2016-01-01
Highlights: • The thermodynamic and economic evaluation of power plant have been studied. • Saving and boosting modes are considered as the same solar field area. • Two modes of operation have been used and simulated on Libyan climate conditions. • The benefit/cost ratios are 1.74 and 1.30 for fuel saving and power boosting mode. • Fuel saving mode is more economical than power boosting mode. - Abstract: The aim of this paper is to study the thermodynamic performance of a proposed integrated solar/North Benghazi combined power plant under Libyan climatic conditions. The parabolic trough collector field with direct steam generation was considered as solar system. Two modes of operations with the same solar field area are considered: fuel saving mode in which the generated solar steam was used to preheat the combustion air in the gas turbine unit and power boosting mode in which the generated solar steam was added into the steam turbine for boosting the electrical power generated from steam turbine unit. Moreover, the economic impact of solar energy is assessed in the form of benefit/cost ratio to justify the substitution potential of such clean energy. This study shows that, for fuel saving mode: the annual saving of natural gas consumption and CO_2 emission are approximately 3001.56 and 7972.25 tons, respectively, in comparison with the conventional North Benghazi combined cycle power plant. For power boosting mode: the annual solar share of electrical energy is approximately 93.33 GW h. The economic analysis of solar supported plant has indicated that the benefit/cost ratios are 1.74 and 1.30 for fuel saving and power boosting mode, therefore, then fuel saving mode is more economical than power boosting mode for the same solar field area, moreover, it reduces the greenhouse CO_2 emission in order to avoid a collapse of the word climate.
Ten Years in the Academic Integrity Trenches: Experiences and Issues
Atkinson, Doug; Nau, S. Zaung; Symons, Christine
2016-01-01
In 2016, our university launched its Academic Integrity Program (AIP) in order to promote and protect academic integrity. All commencing students must complete this online AIP within 14 days of starting their course. Satisfactory completion of this module with a test score of 80% is required before students can access their course materials.…
Hagsäter, S M; Jensen, T Glasdam; Bruus, H; Kutter, J P
2007-10-01
We show that full-image micro-PIV analysis in combination with images of transient particle motion is a powerful tool for experimental studies of acoustic radiation forces and acoustic streaming in microfluidic chambers under piezo-actuation in the MHz range. The measured steady-state motion of both large 5 microm and small 1 microm particles can be understood in terms of the acoustic eigenmodes or standing ultra-sound waves in the given experimental microsystems. This interpretation is supported by numerical solutions of the corresponding acoustic wave equation.
Drossel, Welf-Guntram; Schubert, Andreas; Putz, Matthias; Koriath, Hans-Joachim; Wittstock, Volker; Hensel, Sebastian; Pierer, Alexander; Müller, Benedikt; Schmidt, Marek
2018-01-01
The technique joining by forming allows the structural integration of piezoceramic fibers into locally microstructured metal sheets without any elastic interlayers. A high-volume production of the joining partners causes in statistical deviations from the nominal dimensions. A numerical simulation on geometric process sensitivity shows that the deviations have a high significant influence on the resulting fiber stresses after the joining by forming operation and demonstrate the necessity of a monitoring concept. On this basis, the electromechanical behavior of piezoceramic array transducers is investigated experimentally before, during and after the joining process. The piezoceramic array transducer consists of an arrangement of five electrical interconnected piezoceramic fibers. The findings show that the impedance spectrum depends on the fiber stresses and can be used for in-process monitoring during the joining process. Based on the impedance values the preload state of the interconnected piezoceramic fibers can be specifically controlled and a fiber overload.
Numerical analysis of biological clogging in two-dimensional sand box experiments
DEFF Research Database (Denmark)
Kildsgaard, J.; Engesgaard, Peter Knudegaard
2001-01-01
Two-dimensional models for biological clogging and sorptive tracer transport were used to study the progress of clogging in a sand box experiment. The sand box had been inoculated with a strip of bacteria and exposed to a continuous injection of nitrate and acetate. Brilliant Blue was regularly...... injected during the clogging experiment and digital images of the tracer movement had been converted to concentration maps using an image analysis. The calibration of the models to the Brilliant Blue observations shows that Brilliant Blue has a solid biomass dependent sorption that is not compliant...... with the assumed linear constant Kd behaviour. It is demonstrated that the dimensionality of sand box experiments in comparison to column experiments results in a much lower reduction in hydraulic conductivity Žfactor of 100. and that the bulk hydraulic conductivity of the sand box decreased only slightly. However...
Doummar, Joanna; Kassem, Assaad
2017-04-01
In the framework of a three-year PEER (USAID/NSF) funded project, flow in a Karst system in Lebanon (Assal) dominated by snow and semi arid conditions was simulated and successfully calibrated using an integrated numerical model (MIKE-She 2016) based on high resolution input data and detailed catchment characterization. Point source infiltration and fast flow pathways were simulated by a bypass function and a high conductive lens respectively. The approach consisted of identifying all the factors used in qualitative vulnerability methods (COP, EPIK, PI, DRASTIC, GOD) applied in karst systems and to assess their influence on recharge signals in the different hydrological karst compartments (Atmosphere, Unsaturated zone and Saturated zone) based on the integrated numerical model. These parameters are usually attributed different weights according to their estimated impact on Groundwater vulnerability. The aim of this work is to quantify the importance of each of these parameters and outline parameters that are not accounted for in standard methods, but that might play a role in the vulnerability of a system. The spatial distribution of the detailed evapotranspiration, infiltration, and recharge signals from atmosphere to unsaturated zone to saturated zone was compared and contrasted among different surface settings and under varying flow conditions (e.g., in varying slopes, land cover, precipitation intensity, and soil properties as well point source infiltration). Furthermore a sensitivity analysis of individual or coupled major parameters allows quantifying their impact on recharge and indirectly on vulnerability. The preliminary analysis yields a new methodology that accounts for most of the factors influencing vulnerability while refining the weights attributed to each one of them, based on a quantitative approach.
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)
Directory of Open Access Journals (Sweden)
Mateusz Janiszewski
2018-04-01
Full Text Available Accurate and fast numerical modelling of the borehole heat exchanger (BHE is required for simulation of long-term thermal energy storage in rocks using boreholes. The goal of this study was to conduct an in situ experiment to validate the proposed numerical modelling approach. In the experiment, hot water was circulated for 21 days through a single U-tube BHE installed in an underground research tunnel located at a shallow depth in crystalline rock. The results of the simulations using the proposed model were validated against the measurements. The numerical model simulated the BHE’s behaviour accurately and compared well with two other modelling approaches from the literature. The model is capable of replicating the complex geometrical arrangement of the BHE and is considered to be more appropriate for simulations of BHE systems with complex geometries. The results of the sensitivity analysis of the proposed model have shown that low thermal conductivity, high density, and high heat capacity of rock are essential for maximising the storage efficiency of a borehole thermal energy storage system. Other characteristics of BHEs, such as a high thermal conductivity of the grout, a large radius of the pipe, and a large distance between the pipes, are also preferred for maximising efficiency.
Energy Technology Data Exchange (ETDEWEB)
Bernstein, W.; Hildebrand, V.; Ullrich, B.; Szilagyi, J.
2000-07-01
Power plant reliability depends to a large extent on steam generator operation. Investigations were therefore carried out for early detection of combustion chamber soiling at different operating conditions. Apart from CFD numerical simulations of the gaseous phase and particle tracks, both in the original and coupled with thermochemical calculations, emphasis was given to validations with measured values in the original plant, in combustion chamber models, and in experimental facilities. Three different fuels with different composition and behaviour were investigated, i.e. oil shales, mixed coal, and coal pretreated with sorption agents. Apart from the influence of the temperature and reaction conditions (oxygen concentration) in the vicinity of the particle, also different times of residue were investigated. [German] Die Betriebssicherheit von Kraftanlagen wird massgeblich von der Arbeitsweise der Dampferzeuger bestimmt. Ziel dieses Forschungskomplexes ist es, fruehzeitig Aussagen zum Ansatzverhalten im Feuerraum bei verschiedenen Betriebsbedingungen zu treffen. Neben der numerischen Simulation der Gasphase und der Partikelbahnen mit CFD-Codes im Original und der Kopplung mit thermochemischen Berechnungen stehen vor allem Validierungen mit Messwerten am Original, an Feuerraummodellen und Versuchsanlagen im Vordergrund der Arbeiten. Die hier vorgestellten Untersuchungen erfolgten an drei unterschiedlichen Brennstoffen, die sich sowohl in der Zusammensetzung als auch im Einsatz stark voneinander unterscheiden. Dies sind: Oelschiefer, Mischkohle und vorbehandelte Kohle mit Sorbent. Dabei werden neben den Einfluessen der Temperatur und der Reaktionsbedingung (Sauerstoffgehalt) in der Umgebung des Partikels auch verschiedene Verweilzeiten untersucht. (orig./AKF)
Directory of Open Access Journals (Sweden)
Marc Brunel
2015-04-01
Full Text Available We present the development of a numerical simulator for digital in-line holography applications. In-line holograms of arbitrarily shaped and arbitrarily located objects are calculated using generalized Huygens-Fresnel integrals. The objects are 2D opaque or phase objects. The optical set-up is described by its optical transfer matrix. A wide variety of optical systems, involving windows, spherical or cylindrical lenses, can thus be taken into account. It makes the simulator applicable for design and description of in situ experiments. We discuss future applications of this simulator for detection of nanoparticles in droplets, or calibration of airborne instruments that detect and measure ice crystals in the atmosphere.
Numerical experiment designs. Study of vibratory behaviour of PWR'S control rod clusters
International Nuclear Information System (INIS)
Bosselut, D.; Soulier, B.; Regnier, G.
1997-01-01
The application of Experiment Design method to Finite Element Model (FEM) calculations is an original way of performing parametric studies. It has been used at EDF to simulate on a large parametric domain the vibrations of PWR's control rod cluster and to analyse the rod wear process. In the first part the FEM and the location of excitation sources are described. The calculated values are: rod displacement in the guiding cards, shock forces on the guiding cards and the wear power produced. In the second part, the computed Experiment Domain is described. This method approaches the response surface by a second degree polynomial. The retained model is composed for every parameters of all linear, quadratic and interaction terms (26 coefficients). In all, 34 polynomials have been built to approach the effective shock forces and the mean wear power at each of the 17 guiding points. In the third part the building of the computer Experiment Design is detailed: by Doehlert design adaptation to take into account a qualitative parameter, design optimization by adding four well chosen experiments and finally, design extension by passing from 4 to 6 parameters. In the last part, all the information deduced from application of this method are presented. The influence of parameters on calculated effective shock forces has been determined along rods and response surface have been easily approximated. The systematism and closeness of Experiment Design technique is underlined. Easy simulation of all the response domain by polynomial approach allows comparison with experimental results. (authors)
Directory of Open Access Journals (Sweden)
Tetsuya Ishida
2018-03-01
Full Text Available In November 2011, the Japanese government resolved to build “Revival Roads” in the Tohoku region to accelerate the recovery from the Great East Japan Earthquake of March 2011. Because the Tohoku region experiences such cold and snowy weather in winter, complex degradation from a combination of frost damage, chloride attack from de-icing agents, alkali–silica reaction, cracking and fatigue is anticipated. Thus, to enhance the durability performance of road structures, particularly reinforced concrete (RC bridge decks, multiple countermeasures are proposed: a low water-to-cement ratio in the mix, mineral admixtures such as ground granulated blast furnace slag and/or fly ash to mitigate the risks of chloride attack and alkali–silica reaction, anticorrosion rebar and 6% entrained air for frost damage. It should be noted here that such high durability specifications may conversely increase the risk of early age cracking caused by temperature and shrinkage due to the large amounts of cement and the use of mineral admixtures. Against this background, this paper presents a numerical simulation of early age deformation and cracking of RC bridge decks with full 3D multiscale and multi-chemo-physical integrated analysis. First, a multiscale constitutive model of solidifying cementitious materials is briefly introduced based on systematic knowledge coupling microscopic thermodynamic phenomena and microscopic structural mechanics. With the aim to assess the early age thermal and shrinkage-induced cracks on real bridge deck, the study began with extensive model validations by applying the multiscale and multi-physical integrated analysis system to small specimens and mock-up RC bridge deck specimens. Then, through the application of the current computational system, factors that affect the generation and propagation of early age thermal and shrinkage-induced cracks are identified via experimental validation and full-scale numerical simulation on real
International Nuclear Information System (INIS)
Henry, D.; Berthelot, A.; Cuchet, R.; Chantre, C.; Campbell, M.; Tick, T.
2012-01-01
Hybrid pixel detectors are now widely used in particle physics experiments and are becoming established at synchrotron light sources. They have also stimulated growing interest in other fields and, in particular, in medical imaging. Through the continuous pursuit of miniaturization in CMOS it has been possible to increase the functionality per pixel while maintaining or even shrinking pixel dimensions. The main constraint on the more extensive use of the technology in all fields is the cost of module building and the difficulty of covering large areas seamlessly. On another hand, in the field of electronic component integration, a new approach has been developed in the last years, called 3D Integration. This concept, based on using the vertical axis for component integration, allows improving the global performance of complex systems. Thanks to this technology, the cost and the form factor of components could be decreased and the performance of the global system could be enhanced. In the field of radiation imaging detectors the advantages of 3D Integration come from reduced inter chip dead area even on large surfaces and from improved detector construction yield resulting from the use of single chip 4-side buttable tiles. For many years, numerous R and centres and companies have put a lot of effort into developing 3D integration technologies and today, some mature technologies are ready for prototyping and production. The core technology of the 3D integration is the TSV (Through Silicon Via) and for many years, LETI has developed those technologies for various types of applications. In this paper we present how one of the TSV approaches developed by LETI, called TSV last, has been applied to a readout wafer containing readout chips intended for a hybrid pixel detector assembly. In the first part of this paper, the 3D design adapted to the read-out chip will be described. Then the complete process flow will be explained and, finally, the test strategy adopted and
An investigation of strategies for integrated learning experiences ...
African Journals Online (AJOL)
(NCS, 2002) integrated music, dance, drama and visual arts where possible, while ... for the development of literacy skills, the latter term used by Wagner, ..... for movement ..... Qualitative investigation of young children's music preferences.
Double-Exponentially Decayed Photoionization in CREI Effect: Numerical Experiment on 3D H2+
International Nuclear Information System (INIS)
Feng, Li; Ting-Ying, Wang; Gui-Zhong, Zhang; Wang-Hua, Xiang; III, W. T. Hill
2008-01-01
On the platform of the 3D H 2 + system, we perform a numerical simulation of its photoionization rate under excitation of weak to intense laser intensities with varying pulse durations and wavelengths. A novel method is proposed for calculating the photoionization rate: a double exponential decay of ionization probability is best suited for fitting this rate. Confirmation of the well-documented charge-resonance-enhanced ionization (CREI) effect at medium laser intensity and finding of ionization saturation at high light intensity corroborate the robustness of the suggested double-exponential decay process. Surveying the spatial and temporal variations of electron wavefunctions uncovers a mechanism for the double-exponentially decayed photoionization probability as onset of electron ionization along extra degree of freedom. Henceforth, the new method makes clear the origins of peak features in photoionization rate versus internuclear separation. It is believed that this multi-exponentially decayed ionization mechanism is applicable to systems with more degrees of motion
Graded-index fiber tip optical tweezers: numerical simulation and trapping experiment.
Gong, Yuan; Ye, Ai-Yan; Wu, Yu; Rao, Yun-Jiang; Yao, Yao; Xiao, Song
2013-07-01
Optical fiber tweezers based on a graded-index multimode fiber (GIMMF) tip is proposed. Light propagation characteristics and gradient force distribution near the GIMMF tip are numerically investigated, which are further compared with that of optical fiber tips based on conventional single mode fibers. The simulated results indicated that by selecting optimal GIMMF length, the gradient force of the GIMMF tip tweezers is about 4 times higher than that of the SMF tip tweezers with a same shape. To prove the feasibility of such a new concept, optical trapping of yeast cells with a diameter of ~5 μm using the chemically-etched GIMMF tip is experimentally demonstrated and the trapping force is also calculated.
International Nuclear Information System (INIS)
Song, J.L.; Li, Y.T.; Liu, Z.Q.; Fu, J.H.; Ting, K.L.
2009-01-01
According to the disadvantages of conventional bar cutting technology such as low-cutting speed, inferior section quality, high-processing cost and so on, a kind of novel precision bar cutting technology has been proposed. The cutting mechanism has also been analyzed. Finite element numerical simulation of the bar cutting process under different working conditions has been carried out with DEFORM. The stress and strain fields at different cutting speed and the variation curves of the cutting force and appropriate cutting parameters have been obtained. Scanning electron microscopy analysis of the cutting surface showed that the finite-element simulation result is correct and better cutting quality can be obtained with the developed bar cutting technology and equipment based on high speed and restrained state
Numerical Analysis of a Pulse Detonation Cross Flow Heat Load Experiment
Paxson, Daniel E.; Naples, Andrew .; Hoke, John L.; Schauer, Fred
2011-01-01
A comparison between experimentally measured and numerically simulated, time-averaged, point heat transfer rates in a pulse detonation (PDE) engine is presented. The comparison includes measurements and calculations for heat transfer to a cylinder in crossflow and to the tube wall itself using a novel spool design. Measurements are obtained at several locations and under several operating conditions. The measured and computed results are shown to be in substantial agreement, thereby validating the modeling approach. The model, which is based in computational fluid dynamics (CFD) is then used to interpret the results. A preheating of the incoming fuel charge is predicted, which results in increased volumetric flow and subsequent overfilling. The effect is validated with additional measurements.
Directory of Open Access Journals (Sweden)
Xiaocui Wu
2015-11-01
Full Text Available Fluid–structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid–structure interaction is noticeable and should be considered for non-rigid airships. Flow-induced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximately 60% compared with that of the rigid model under a high angle of attack.
Viswanathan, H. S.; Carey, J. W.; Karra, S.; Porter, M. L.; Rougier, E.; Kang, Q.; Makedonska, N.; Hyman, J.; Jimenez Martinez, J.; Frash, L.; Chen, L.
2015-12-01
Hydraulic fracturing phenomena involve fluid-solid interactions embedded within coupled thermo-hydro-mechanical-chemical (THMC) processes over scales from microns to tens of meters. Feedbacks between processes result in complex dynamics that must be unraveled if one is to predict and, in the case of unconventional resources, facilitate fracture propagation, fluid flow, and interfacial transport processes. The proposed work is part of a broader class of complex systems involving coupled fluid flow and fractures that are critical to subsurface energy issues, such as shale oil, geothermal, carbon sequestration, and nuclear waste disposal. We use unique LANL microfluidic and triaxial core flood experiments integrated with state-of-the-art numerical simulation to reveal the fundamental dynamics of fracture-fluid interactions to characterize the key coupled processes that impact hydrocarbon production. We are also comparing CO2-based fracturing and aqueous fluids to enhance production, greatly reduce waste water, while simultaneously sequestering CO2. We will show pore, core and reservoir scale simulations/experiments that investigate the contolling mechanisms that control hydrocarbon production.
Directory of Open Access Journals (Sweden)
Poruba Z.
2009-06-01
Full Text Available For the numerical solution of elasto-plastic problems with use of Newton-Raphson method in global equilibrium equation it is necessary to determine the tangent modulus in each integration point. To reach the parabolic convergence of Newton-Raphson method it is convenient to use so called algorithmic tangent modulus which is consistent with used integration scheme. For more simple models for example Chaboche combined hardening model it is possible to determine it in analytical way. In case of more robust macroscopic models it is in many cases necessary to use the approximation approach. This possibility is presented in this contribution for radial return method on Chaboche model. An example solved in software Ansys corresponds to line contact problem with assumption of Coulomb's friction. The study shows at the end that the number of iteration of N-R method is higher in case of continuum tangent modulus and many times higher with use of modified N-R method, initial stiffness method.
Validation experiment of a numerically processed millimeter-wave interferometer in a laboratory
Energy Technology Data Exchange (ETDEWEB)
Kogi, Y., E-mail: kogi@fit.ac.jp; Higashi, T.; Matsukawa, S. [Department of Information Electronics, Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Mase, A. [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka 816-0811 (Japan); Kohagura, J.; Yoshikawa, M. [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Nagayama, Y.; Kawahata, K. [National Institute for Fusion Science, Toki, Gifu 509-5202 (Japan); Kuwahara, D. [Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)
2014-11-15
We propose a new interferometer system for density profile measurements. This system produces multiple measurement chords by a leaky-wave antenna driven by multiple frequency inputs. The proposed system was validated in laboratory evaluation experiments. We confirmed that the interferometer generates a clear image of a Teflon plate as well as the phase shift corresponding to the plate thickness. In another experiment, we confirmed that quasi-optical mirrors can produce multiple measurement chords; however, the finite spot size of the probe beam degrades the sharpness of the resulting image.
International Nuclear Information System (INIS)
Xiao Zejun; Jia Dounan; Jiang Xulun; Chen Bingde
2003-01-01
Since the foundation of Nuclear Power Institute of China, it has successively designed various engineering experimental facilities, and constructed nuclear power experimental research base, and accumulated rich construction experiences of nuclear power integrated test facility. The author presents experience on design, construction and commissioning of nuclear power integrated test facility
Review of recent benchmark experiments on integral test for high energy nuclear data evaluation
Energy Technology Data Exchange (ETDEWEB)
Nakashima, Hiroshi; Tanaka, Susumu; Konno, Chikara; Fukahori, Tokio; Hayashi, Katsumi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-11-01
A survey work of recent benchmark experiments on an integral test for high energy nuclear data evaluation was carried out as one of the work of the Task Force on JENDL High Energy File Integral Evaluation (JHEFIE). In this paper the results are compiled and the status of recent benchmark experiments is described. (author)
Numerical Experiments of Counterflowiing Jet Effects on Supersonic Slender-Body Configurations
Venkatachari, Balaji Shankar; Mullane, Michael; Cheng, Gary C.; Chang, Chau-Lyan
2015-01-01
Previous studies have demonstrated that the use of counterflowing jets can greatly reduce the drag and heat loads on blunt-body geometries, especially when the long penetration mode jet condition can be established. Previously, the authors had done some preliminary numerical studies to determine the ability to establish long penetration mode jets on a typical Mach 1.6 slender configuration, and study its impact on the boom signature. The results indicated that a jet with a longer penetration length was required to achieve any impact on the boom signature of a typical Mach 1.6 slender configuration. This paper focuses on an in-depth parametric study, done using the space-time conservation element solution element Navier-Stokes flow solver, for investigating the effect of various counterflowing jet conditions/configurations on two supersonic slender-body models (cone-cylinder and quartic body of revolution). The study is aimed at gaining a better understanding of the relationship between the shock penetration length and reduction of drag and boom signature for these two supersonic slender-body configurations. Different jet flow rates, Mach numbers, nozzle jet exit diameters and jet-to-base diameter ratios were examined. The results show the characteristics of a short-to-long-to-short penetration-mode pattern with the increase of jet mass flow rates, observed across various counterflowing jet nozzle configurations. Though the optimal shock penetration length for potential boom-signature mitigation is tied to the long penetration mode, it often results in a very unsteady flow and leads to large oscillations of surface pressure and drag. Furthermore, depending on the geometry of the slender body, longer jet penetration did not always result in maximum drag reduction. For the quartic geometry, the maximum drag reduction corresponds well to the longest shock penetration length, while this was not the case for the cone-cylinder-as the geometry was already optimized for
Experience of developing an integrated nondestructive assay system
International Nuclear Information System (INIS)
Hsue, S.T.; Baker, M.P.
1987-01-01
A consortium of laboratories is collaborating with the Savannah River Plant to develop an integrated system of state-of-the-art nondestructive assay (NDA) instrumentation to provide nuclear materials accounting and process control information for a new plutonium scrap recovery facility. Individual instruments report assay results to an instrument control computer (ICC); the ICC, in turn, is part of a larger computer network that includes computers that perform process control and materials accounting functions. The design of the integrated NDA measurement system is shown. Each NDA instrument that is part of the integrated system is microcomputer-based and thus is capable of stand-alone operation if the central computer is out of service. Certain hardware features, such as microcomputers, pulse processing modules, and multichannel analyzers, are standardized throughout the system. Another standard feature is the communication between individual NDA instruments and the ICC. The most unique phase of the project is the integral staging. The primary purpose of this phase is to check the communications between various computers and to verify the ICC software during the operation of the NDA instruments. Implementing this integrated system in a process environment represents a major step in realizing the full capabilities of modern NDA instrumentation
Vertical integration of medical education: Riverland experience, South Australia.
Rosenthal, D R; Worley, P S; Mugford, B; Stagg, P
2004-01-01
Vertical integration of medical education is currently a prominent international topic, resulting from recent strategic initiatives to improve medical education and service delivery in areas of poorly met medical need. In this article, vertical integration of medical education is defined as 'a grouping of curricular content and delivery mechanisms, traversing the traditional boundaries of undergraduate, postgraduate and continuing medical education, with the intent of enhancing the transfer of knowledge and skills between those involved in the learning-teaching process'. Educators closely involved with vertically integrated teaching in the Riverland of South Australia present an analytical description of the educational dynamics of this system. From this analysis, five elements are identified which underpin the process of successful vertical integration: (1) raised educational stakes; (2) local ownership; (3) broad university role; (4) longer attachments; and (5) shared workforce vision. Given the benefits to the Riverland medical education programs described in this paper, it is not surprising that vertical integration of medical education is a popular goal in many rural regions throughout the world. Although different contexts will result in different functional arrangements, it could be argued that the five principles outlined in this article can be applied in any region.
Javernick, L.; Bertoldi, W.; Redolfi, M.
2017-12-01
Accessing or acquiring high quality, low-cost topographic data has never been easier due to recent developments of the photogrammetric techniques of Structure-from-Motion (SfM). Researchers can acquire the necessary SfM imagery with various platforms, with the ability to capture millimetre resolution and accuracy, or large-scale areas with the help of unmanned platforms. Such datasets in combination with numerical modelling have opened up new opportunities to study river environments physical and ecological relationships. While numerical models overall predictive accuracy is most influenced by topography, proper model calibration requires hydraulic data and morphological data; however, rich hydraulic and morphological datasets remain scarce. This lack in field and laboratory data has limited model advancement through the inability to properly calibrate, assess sensitivity, and validate the models performance. However, new time-lapse imagery techniques have shown success in identifying instantaneous sediment transport in flume experiments and their ability to improve hydraulic model calibration. With new capabilities to capture high resolution spatial and temporal datasets of flume experiments, there is a need to further assess model performance. To address this demand, this research used braided river flume experiments and captured time-lapse observed sediment transport and repeat SfM elevation surveys to provide unprecedented spatial and temporal datasets. Through newly created metrics that quantified observed and modeled activation, deactivation, and bank erosion rates, the numerical model Delft3d was calibrated. This increased temporal data of both high-resolution time series and long-term temporal coverage provided significantly improved calibration routines that refined calibration parameterization. Model results show that there is a trade-off between achieving quantitative statistical and qualitative morphological representations. Specifically, statistical
Directory of Open Access Journals (Sweden)
Yuji Ohya
2016-12-01
Full Text Available A new type of solar tower was developed through laboratory experiments and numerical analyses. The solar tower mainly consists of three components. The transparent collector area is an aboveground glass roof, with increasing height toward the center. Attached to the center of the inside of the collector is a vertical tower within which a wind turbine is mounted at the lower entry to the tower. When solar radiation heats the ground through the glass roof, ascending warm air is guided to the center and into the tower. A solar tower that can generate electricity using a simple structure that enables easy and less costly maintenance has considerable advantages. However, conversion efficiency from sunshine energy to mechanical turbine energy is very low. Aiming to improve this efficiency, the research project developed a diffuser-type tower instead of a cylindrical tower, and investigated a suitable diffuser shape for practical use. After changing the tower height and diffuser open angle, with a temperature difference between the ambient air aloft and within the collector, various diffuser tower shapes were tested by laboratory experiments and numerical analyses. As a result, it was found that a diffuser tower with a semi-open angle of 4° is an optimal shape, producing the fastest updraft at each temperature difference in both the laboratory experiments and numerical analyses. The relationships between thermal updraft speed and temperature difference and/or tower height were confirmed. It was found that the thermal updraft velocity is proportional to the square root of the tower height and/or temperature difference.
International Nuclear Information System (INIS)
Chih-Lung Chen; Institute of Nuclear Energy Research, Taoyuan, Taiwan; Tsing-Hai Wang; Shi-Ping Teng; Ching-Hor Lee
2014-01-01
Diffusion is a dominant mechanism regulating the transport of released nuclides. The through-diffusion method is typically applied to determine the diffusion coefficients (D). Depending on the design of the experiment, the concentrations in the source term [i.e., inlet reservoir (IR)] or the end term [i.e., outlet reservoir (OR)] can be fixed or vary. The combinations involve four distinct models (i.e., the CC-CC model, CC-VC model, VC-CC model, and the VC-VC model). Studies discussing the VC-CC model are scant. An analytical method considering the decay effect is required to accurately interpret the radioactive nuclide diffusion experiment results. Therefore, we developed a CC-CC model and a CC-VC model with a decay effect and the simplified formulas of these two models to determine the diffusion coefficient (i.e., the CC-CC method and CC-VC method). We also proposed two simplified methods using the VC-VC model to determine the diffusion coefficient straightforwardly based upon the concentration variation in IR and OR. More importantly, the best advantage of proposed method over others is that one can derive three diffusion coefficients based on one run of experiment. In addition, applying our CC-VC method to those data reported from Radiochemica Acta 96:111-117, 2008; and J Contam Hydrol 35:55-65, 1998, derived comparable diffusion coefficient lying in the identical order of magnitude. Furthermore, we proposed a formula to determine the conceptual critical time (Tc), which is particularly beneficial for the selection of using CC-VC or VC-VC method. Based on our proposed method, it becomes possible to calculate diffusion coefficient from a through-diffusion experiment in a shorter period of time. (author)
Experiments and numerical studies on a Syngas-fired Ultra low NOx combustor
S, Krishna; Ravikrishna, R. V.
2017-01-01
Exhaust measurements of temperature and pollutants in a syngas-fired model trapped vortex combustor for stationary power generation applications are reported. The performance was further evaluated for configurations where mixing enhancement was obtained using struts in the mainstream flow. Mainstream premixing of fuel was also studied to investigate its effect on emissions. The exhaust temperature pattern factor was found to be poor for baseline cases, but improved with the introduction of struts. NO emissions were steadily below 3-ppm across various flow conditions, whereas CO emissions tended to increase with increasing Momentum Flux Ratios (MFRs) and mainstream fuel addition. Combustion efficiencies ~96% were observed for all conditions. The performance characteristics were found to be favourable at higher MFRs with low pattern factors and high combustion efficiencies. Numerical simulations employing RANS and LES with Presumed Probability Distribution Function (PPDF) model were also carried out. Mixture fraction profiles in the TVC cavity for non-reacting conditions show that LES simulations are able to capture the mean mixing field better than the RANS-based approach. This is attributed to the prediction of the jet decay rate and is reflected on the mean velocity magnitude fields, which reinforce this observation at different sections in the cavity. Both RANS and LES simulations show close agreement with the experimentally measured OH concentration, however, the RANS approach does not perform satisfactorily in capturing the trend of velocity magnitude. LES simulations clearly capture the trend observed in exhaust measurements which is primarily attributed to the flame stabilization mechanism.
Ghamlouch, T.; Roux, S.; Bailleul, J.-L.; Lefèvre, N.; Sobotka, V.
2017-10-01
Today's aerospace industrial first priority is the quality improvement of the composite material parts with the reduction of the manufacturing time in order to increase their quality/cost ratio. A fabrication method that could meet these specifications especially for large parts is the autoclave curing process. In fact the autoclave molding ensures the thermal control of the composite parts during the whole curing cycle. However the geometry of the tools as well as their positioning in the autoclave induce non uniform and complex flows around composite parts. This heterogeneity implies non-uniform heat transfers which can directly impact on part quality. One of the main challenges is therefore to describe the flow field inside an autoclave as well as the convective heat transfer from the heated pressurized gas to the composite part and the mold. For this purpose, and given the technical issues associated with instrumentation and measurements in actual autoclaves, an autoclave model was designed and then manufactured based on similarity laws. This tool allows the measurement of the flow field around representative real industrial molds using the PIV technique and the characterization of the heat transfer thanks to thermal instrumentation. The experimental results are then compared with those derived from numerical simulations using a commercial RANS CFD code. This study aims at developing a semi-empirical approach for the prediction of the heat transfer coefficient around the parts and therefore predicts its thermal history during the process with a view of optimization.
International Nuclear Information System (INIS)
Serizawa, A.; Huda, K.; Yamada, Y.; Kataoka, I.
1997-01-01
Experimental and numerical analyses were carried out on vertically upward air-water bubbly two-phase flow behavior in both horizontal and inclined rod bundles with either in-line or staggered array. The inclination angle of the rod bundle varied from 0 to 60 with respect to the horizontal. The measured phase distribution indicated non-uniform characteristics, particularly in the direction of the rod axis when the rods were inclined. The mechanisms for this non-uniform phase distribution is supposed to be due to: (1) Bubble segregation phenomenon which depends on the bubble size and shape: (2) bubble entrainment by the large scale secondary flow induced by the pressure gradient in the horizontal direction which crosses the rod bundle; (3) effects of bubble entrapment by vortices generated in the wake behind the rods which travel upward along the rod axis; and (4) effect of bubble entrainment by local flows sliding up along the front surface of the rods. The liquid velocity and turbulence distributions were also measured and discussed. In these speculations, the mechanisms for bubble bouncing at the curved rod surface and turbulence production induced by a bubble were discussed, based on visual observations. Finally, the bubble behaviors in vertically upward bubbly two-phase flow across horizontal rod bundle were analyzed based on a particle tracking method (one-way coupling). The predicted bubble trajectories clearly indicated the bubble entrapment by vortices in the wake region. (orig.)
Saleh, Mohamed Nasr
2016-01-08
Damage initiation and evolution of three-dimensional (3D) orthogonal woven carbon fibre composite (3DOWC) is investigated experimentally and numerically. Meso-scale homogenisation of the representative volume element (RVE) is utilised to predict the elastic properties, simulate damage initiation and evolution when loaded in tension. The effect of intra-yarns transverse cracking and shear diffused damage on the in-plane transverse modulus and shear modulus is investigated while one failure criterion is introduced to simulate the matrix damage. The proposed model is based on two major assumptions. First, the effect of the binder yarns, on the in-plane properties, is neglected, so the 3DOWC unit cell can be approximated as a (0o/90o) cross-ply laminate. Second, a micro-mechanics based damage approach is used at the meso-scale, so damage indicators can be correlated, explicitly, to the density of cracks within the material. Results from the simulated RVE are validated against experimental results along the warp (0o direction) and weft (90o direction). This approach paves the road for more predictive models as damage evolution laws are obtained from micro mechanical considerations and rely on few well-defined material parameters. This largely differs from classical damage mechanics approaches in which the evolution law is obtained by retrofitting experimental observations.
Saleh, Mohamed Nasr; Lubineau, Gilles; Potluri, Prasad; Withers, Philip; Soutis, Constantinos
2016-01-01
Damage initiation and evolution of three-dimensional (3D) orthogonal woven carbon fibre composite (3DOWC) is investigated experimentally and numerically. Meso-scale homogenisation of the representative volume element (RVE) is utilised to predict the elastic properties, simulate damage initiation and evolution when loaded in tension. The effect of intra-yarns transverse cracking and shear diffused damage on the in-plane transverse modulus and shear modulus is investigated while one failure criterion is introduced to simulate the matrix damage. The proposed model is based on two major assumptions. First, the effect of the binder yarns, on the in-plane properties, is neglected, so the 3DOWC unit cell can be approximated as a (0o/90o) cross-ply laminate. Second, a micro-mechanics based damage approach is used at the meso-scale, so damage indicators can be correlated, explicitly, to the density of cracks within the material. Results from the simulated RVE are validated against experimental results along the warp (0o direction) and weft (90o direction). This approach paves the road for more predictive models as damage evolution laws are obtained from micro mechanical considerations and rely on few well-defined material parameters. This largely differs from classical damage mechanics approaches in which the evolution law is obtained by retrofitting experimental observations.
Directory of Open Access Journals (Sweden)
Julien Michels
2014-01-01
Full Text Available This paper presents a study on the load carrying capacity of reinforced concrete (RC beams strengthened with externally bonded (EB carbon fiber reinforced polymer (CFRP strips prestressed up to 0.6% in strain. At the strip ends, the innovative gradient anchorage is used instead of conventional mechanical fasteners. This method, based on the epoxy resin’s ability to rapidly cure under high temperatures, foresees a sector-wise heating followed by a gradual decrease of the initial prestress force towards the strip ends. The experimental investigation shows a promising structural behavior, resulting in high strip tensile strains, eventually almost reaching tensile failure of the composite strip. Additionally, ductility when considering deflection at steel yielding and at ultimate load is satisfying, too. From a practical point of view, it is demonstrated that premature strip grinding in the anchorage zone is not beneficial. In addition, a non-commercial 1D finite element code has been enlarged to an EB reinforcement with prestressed composite strips. A bilinear bond stress-slip relation obtained in earlier investigations is introduced as an additional failure criterion to the code. The numerical code is able to almost perfectly predict the overall structural behavior. Furthermore, the calculations are used for comparison purposes between an initially unstressed and a prestressed externally bonded composite reinforcement. The increase in cracking and yielding load, as well as differences in structural stiffness are apparent.
Experiments and numerical studies on a Syngas-fired Ultra low NOx combustor
S, Krishna
2017-06-06
Exhaust measurements of temperature and pollutants in a syngas-fired model trapped vortex combustor for stationary power generation applications are reported. The performance was further evaluated for configurations where mixing enhancement was obtained using struts in the mainstream flow. Mainstream premixing of fuel was also studied to investigate its effect on emissions. The exhaust temperature pattern factor was found to be poor for baseline cases, but improved with the introduction of struts. NO emissions were steadily below 3-ppm across various flow conditions, whereas CO emissions tended to increase with increasing Momentum Flux Ratios (MFRs) and mainstream fuel addition. Combustion efficiencies ~96% were observed for all conditions. The performance characteristics were found to be favourable at higher MFRs with low pattern factors and high combustion efficiencies. Numerical simulations employing RANS and LES with Presumed Probability Distribution Function (PPDF) model were also carried out. Mixture fraction profiles in the TVC cavity for non-reacting conditions show that LES simulations are able to capture the mean mixing field better than the RANS-based approach. This is attributed to the prediction of the jet decay rate and is reflected on the mean velocity magnitude fields, which reinforce this observation at different sections in the cavity. Both RANS and LES simulations show close agreement with the experimentally measured OH concentration, however, the RANS approach does not perform satisfactorily in capturing the trend of velocity magnitude. LES simulations clearly capture the trend observed in exhaust measurements which is primarily attributed to the flame stabilization mechanism.
Energy Technology Data Exchange (ETDEWEB)
Chai, Penghui, E-mail: phchai@vis.t.u-tokyo.ac.jp; Kondo, Masahiro; Erkan, Nejdet; Okamoto, Koji
2016-05-15
Highlights: • Multiphysics models were developed based on Moving Particle Semi-implicit method. • Mixing process, chemical reaction can be simulated in MCCI calculation. • CCI-2 experiment was simulated to validate the models. • Simulation and experimental results for sidewall ablation agree well. • Simulation results confirm the rapid erosion phenomenon observed in the experiment. - Abstract: Numerous experiments have been performed to explore the mechanisms of molten core-concrete interaction (MCCI) phenomena since the 1980s. However, previous experimental results show that uncertainties pertaining to several aspects such as the mixing process and crust behavior remain. To explore the mechanism governing such aspects, as well as to predict MCCI behavior in real severe accident events, a number of simulation codes have been developed for process calculations. However, uncertainties exist among the codes because of the use of different empirical models. In this study, a new computational code is developed using multiphysics models to simulate MCCI phenomena based on the moving particle semi-implicit (MPS) method. Momentum and energy equations are used to solve the velocity and temperature fields, and multiphysics models are developed on the basis of the basic MPS method. The CCI-2 experiment is simulated by applying the developed code. With respect to sidewall ablation, good agreement is observed between the simulation and experimental results. However, axial ablation is slower in the simulation, which is probably due to the underestimation of the enhancement effect of heat transfer provided by the moving bubbles at the bottom. In addition, the simulation results confirm the rapid erosion phenomenon observed in the experiment, which in the numerical simulation is explained by solutal convection provided by the liquid concrete at the corium/concrete interface. The results of the comparison of different model combinations show the effect of each
IBERINCO in the foreign trade: the integration experience
International Nuclear Information System (INIS)
Lopez, F. J.; Sanchez Mayoral, M. L.; Garcia, P. J.
2002-01-01
The universal tendencies show that nations integrate into large communities to strengthen each other and to share cultures and economies. The integration goes beyond free commerce treaties, opening of the import and export trade shaping unified policies on private sector and reaches into daily life and in the practice of organisations, generating substantial changes in the way of life of people. The companies that will survive in the X XI century will not operate in isolated mood but will have to be able to integrate products and services from other sources adding in the process the value obtained from their basic skills surrounding around their products others non specific of their business and offering to their customers products and services well defined that will make them more valuable and different from their competitions. (Author)
Integrated project management information systems: the French nuclear industry experience
International Nuclear Information System (INIS)
Jacquin, J.-C.; Caupin, G.-M.
1990-01-01
The article discusses the desirability of integrated project management systems within the French nuclear power industry. Change in demand for nuclear generation facilities over the last two decades has necessitated a change of policy concerning organization, cost and planning within the industry. Large corporate systems can benefit from integrating equipment and bulk materials tracking. Project management for the nuclear industry will, in future, need to incorporate computer aided design tools and project management information systems data bases as well as equipment and planning data. (UK)
Integrated project management information systems: the French nuclear industry experience
Energy Technology Data Exchange (ETDEWEB)
Jacquin, J.-C.; Caupin, G.-M.
1990-03-01
The article discusses the desirability of integrated project management systems within the French nuclear power industry. Change in demand for nuclear generation facilities over the last two decades has necessitated a change of policy concerning organization, cost and planning within the industry. Large corporate systems can benefit from integrating equipment and bulk materials tracking. Project management for the nuclear industry will, in future, need to incorporate computer aided design tools and project management information systems data bases as well as equipment and planning data. (UK).
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...
International Nuclear Information System (INIS)
Wang Hongjuan; Shen Chengcai; Lin Jun
2009-01-01
The origin of the Moreton wave observed in the chromosphere and the EIT wave observed in the corona during the eruption remains an active research subject. We investigate numerically in this work the evolutionary features of the magnetic configuration that includes a current-carrying flux rope, which is used to model the filament, after the loss of equilibrium in the system takes place in a catastrophic fashion. Rapid motions of the flux rope following the catastrophe invoke the velocity vortices behind the rope, and may also invoke slow- and fast-mode shocks in front of the rope. The velocity vortices at each side of the flux rope propagate roughly horizontally away from the area where they are produced, and both shocks expand toward the flank of the flux rope. The fast shock may eventually reach the bottom boundary and produce two echoes moving back into the corona, but the slow one and the vortices totally decay somewhere in the lower corona before arriving of the bottom boundary. The interaction of the fast shock with the boundary leads to disturbance that accounts for the Moreton wave observed in Hα, and the disturbance in the corona caused by the slow shock and the velocity vortices should account for the EIT wave whose speed is about 40% that of the Moreton wave. The implication of these results to the observed correlation of the type II radio burst to the fast- and the slow-mode shocks and that of EIT waves to coronal mass ejections and flares has also been discussed.
The time-dependent simplified P2 equations: Asymptotic analyses and numerical experiments
International Nuclear Information System (INIS)
Shin, U.; Miller, W.F. Jr.
1998-01-01
Using an asymptotic expansion, the authors found that the modified time-dependent simplified P 2 (SP 2 ) equations are robust, high-order, asymptotic approximations to the time-dependent transport equation in a physical regime in which the conventional time-dependent diffusion equation is the leading-order approximation. Using diffusion limit analysis, they also asymptotically compared three competitive time-dependent equations (the telegrapher's equation, the time-dependent SP 2 equations, and the time-dependent simplified even-parity equation). As a result, they found that the time-dependent SP 2 equations contain higher-order asymptotic approximations to the time-dependent transport equation than the other competitive equations. The numerical results confirm that, in the vast majority of cases, the time-dependent SP 2 solutions are significantly more accurate than the time-dependent diffusion and the telegrapher's solutions. They have also shown that the time-dependent SP 2 equations have excellent characteristics such as rotational invariance (which means no ray effect), good diffusion limit behavior, guaranteed positivity in diffusive regimes, and significant accuracy, even in deep-penetration problems. Through computer-running-time tests, they have shown that the time-dependent SP 2 equations can be solved with significantly less computational effort than the conventionally used, time-dependent S N equations (for N > 2) and almost as fast as the time-dependent diffusion equation. From all these results, they conclude that the time-dependent SP 2 equations should be considered as an important competitor for an improved approximately transport equations solver. Such computationally efficient time-dependent transport models are important for problems requiring enhanced computational efficiency, such as neutronics/fluid-dynamics coupled problems that arise in the analyses of hypothetical nuclear reactor accidents
Energy Technology Data Exchange (ETDEWEB)
Callaghan, David P.; Nielsen, Peter [The University of Queensland, School of Civil Engineering, Brisbane (Australia); Ahmadi, Afshin [Kellogg Brown and Root Pty Ltd, Brisbane, QLD (Australia)
2011-12-15
Flume measurements of a one-dimensional sliding hump starting from rest in quiescence fresh water indicate that when the hump travels at speed less than the shallow-water wave celerity, three waves emerge, travelling in two directions. One wave travels in the opposite direction to the sliding hump at approximately the shallow-water wave celerity (backward free wave). Another wave travels approximately in step with the hump (forced wave), and the remaining wave travels in the direction of the hump at approximately the shallow-water wave celerity (forward free wave). These experiments were completed for a range of sliding hump speed relative to the shallow-water wave celerity, up to unity of this ratio, to investigate possible derivation from solutions of the Euler equation with non-linear and non-hydrostatic terms being included or excluded. For the experimental arrangements tested, the forced waves were negative (depression or reduced water surface elevation) waves while the free waves were positive (bulges or increased water surface elevation). For experiments where the sliding hump travelled at less than 80% of the shallow-water wave celerity did not include transient behaviour measurements (i.e. when the three waves still overlapped). The three wave framework was partially supported by these measurements in that the separated forward and forced waves were compared to measurements. For the laboratory scale experiments, the forward free wave height was predicted reasonably by the long-wave equation (ignoring non-linear and non-hydrostatic terms) when the sliding hump speed was less than 80% of the shallow-water wave celerity. The forced wave depression magnitude required the Euler equations for all hump speed tested. The long-wave solution, while being valid in a limited parameter range, does predict the existence of the three waves as found in these experiments (forward travelling waves measured quantitatively while the backward travelling waves visually by video
Numerical simulations for the study of a cosmic γ-ray imagery experiment
International Nuclear Information System (INIS)
Monnier, C.
1982-07-01
Basic principles of imagery are reviewed and their applications to a γ-ray imagery device are explained. This device is based on a coded mask associated with a detector which is sensitive to the position of interaction of the γ-ray photons. A group of simulation programs is described. These programs are for use in evaluating the performance of such an experiment the sensitivity, the angular resolution, and that for different configurations. The influence of an inhomogeneous background noise on the detector has also been studied [fr
A SURVEY ON INDIAN EXPERIENCE ON INTEGRATED MANAGEMENT STANDARDS (IMS
Directory of Open Access Journals (Sweden)
H. Khanna
2009-09-01
Full Text Available Adoption of management systems standards is a key issue in manufacturing industry in India. Following the global trend quality and environmental issues are gaining importance. However the number of ISO 14001 certified companies are much less in India as compared to ISO 9001. The integration of ISO 14001 with ISO 9001 may help companies to sustain competitive advantage and overcome disappointments with quality standards and in turn encourage companies to adopt good environmental practices. The aim of this research is to study the implementation of integrated management standards (IMS by the manufacturing organizations in India. The different aspects of integration and benefits of IMS implementation are analyzed. This r esearch is based on empirical study carried out in Indian manufacturing firms, involving the application of a questionnaire. This questionnaire was tested on 50 manufacturing companies in India. The study reveals that focus on stakeholders; top management commitment and training are critical success factors for implementation of IMS. The main benefits of integration are discussed. The small sample size is one of the major limitations of this study. The paper informs the managers in manufacturing organizations and practitioners of management system standards especially in developing countries about IMS and will enable them to adopt IMS in future so that those organizations may not implement multiple and overlapping MSS(Management System Standards.
An investigation of strategies for integrated learning experiences ...
African Journals Online (AJOL)
Pre-determined and emergent codes based on grounded theory showed that it is possible to integrate theory with practice within one art subject by teaching theoretical work in the context of practical work, thus optimizing the limited time allocated to arts and culture education in school timetables. Keywords: arts; arts and ...
Clinical experience of integrative cancer immunotherapy with GcMAF.
Inui, Toshio; Kuchiike, Daisuke; Kubo, Kentaro; Mette, Martin; Uto, Yoshihiro; Hori, Hitoshi; Sakamoto, Norihiro
2013-07-01
Immunotherapy has become an attractive new strategy in the treatment of cancer. The laboratory and clinical study of cancer immunotherapy is rapidly advancing. However, in the clinical setting, the results of cancer immunotherapy are mixed. We therefore contend that cancer immunotherapy should be customized to each patient individually based on their immune status and propose an integrative immunotherapy approach with second-generation group-specific component macrophage activating factor (GcMAF)-containing human serum. The standard protocol of our integrative cancer immunotherapy is as follows: i) 0.5 ml GcMAF-containing human serum is administered intramuscularly or subcutaneously once or twice per week for the duration of cancer therapy until all cancer cells are eradicated; ii) hyper T/natural killer (NK) cell therapy is given once per week for six weeks; iii) high-dose vitamin C is administered intravenously twice per week; iv) alpha lipoic acid (600 mg) is administered orally daily; v) vitamin D3 (5,000-10,000 IU) is administered orally daily. By March 2013, Saisei Mirai have treated over 345 patients with GcMAF. Among them we here present the cases of three patients for whom our integrative immunotherapy was remarkably effective. The results of our integrative immunotherapy seem hopeful. We also plan to conduct a comparative clinical study.>
Integrated product development and experience of communication in education
H. Ihle; Ir. Dick van Schenk Brill; Ir. Peter van Kollenburg; Ir. H.E.V. Veenstra
2000-01-01
The Technical Departments at the Fontys University of Professional Education in Eindhoven, The Netherlands, offer a course which is devel-oped around the principles of Concurrent Engi-neering. Integrated Product Development (IPD) project teams are multi-disciplinary groups which develop products in
Experiences with an integrated management system for aircraft maintenance
International Nuclear Information System (INIS)
Huber, U.
1993-01-01
For 20 years, SWISSAIR has employed an integrated information system for aircraft maintenance. To date, a wide range of functions has been set up in their own development. For the future SWISSAIR is increasingly basing on the use of SAP/standard software packages. 10 figs
Newmann, Sara J; Zakaras, Jennifer M; Tao, Amy R; Onono, Maricianah; Bukusi, Elizabeth A; Cohen, Craig R; Steinfeld, Rachel; Grossman, Daniel
2016-01-01
With high rates of unintended pregnancy in sub-Saharan Africa, integration of family planning (FP) into HIV care is being explored as a strategy to reduce unmet need for contraception. Perspectives and experiences of healthcare providers are critical in order to create sustainable models of integrated care. This qualitative study offers insight into how HIV care providers view and experience the benefits and challenges of providing integrated FP/HIV services in Nyanza Province, Kenya. Sixteen individual interviews were conducted among healthcare workers at six public sector HIV care facilities one year after the implementation of integrated FP and HIV services. Data were transcribed and analyzed qualitatively using grounded theory methods and Atlas.ti. Providers reported a number of benefits of integrated services that they believed increased the uptake and continuation of contraceptive methods. They felt that integrated services enabled them to reach a larger number of female and male patients and in a more efficient way for patients compared to non-integrated services. Availability of FP services in the same place as HIV care also eliminated the need for most referrals, which many providers saw as a barrier for patients seeking FP. Providers reported many challenges to providing integrated services, including the lack of space, time, and sufficient staff, inadequate training, and commodity shortages. Despite these challenges, the vast majority of providers was supportive of FP/HIV integration and found integrated services to be beneficial to HIV-infected patients. Providers' concerns relating to staffing, infrastructure, and training need to be addressed in order to create sustainable, cost-effective FP/HIV integrated service models.
International Nuclear Information System (INIS)
Moesinger, H.
1979-08-01
The computer program DRIX-2D has been developed from SOLA-DF. The essential elements of the program structure are described. In order to verify DRIX-2D an Edwards-Blowdown-Experiment is calculated and other numerical results are compared with steady state experiments and models. Numerical experiments on transient two-phase flow, occurring in the broken pipe of a PWR in the case of a hypothetic LOCA, are performed. The essential results of the two-dimensional calculations are: 1. The appearance of a radial profile of void-fraction, velocity, sound speed and mass flow-rate inside the blowdown nozzle. The reason for this is the flow contraction at the nozzle inlet leading to more vapour production in the vicinity of the pipe wall. 2. A comparison between modelling in axisymmetric and Cartesian coordinates and calculations with and without the core barrel show the following: a) The three-dimensional flow pattern at the nozzle inlet is poorly described using Cartesian coordinates. In consequence a considerable difference in pressure history results. b) The core barrel alters the reflection behaviour of the pressure waves oscillating in the blowdown-nozzle. Therefore, the core barrel should be modelled as a wall normal to the nozzle axis. (orig./HP) [de
Numerical Simulation of a Tracer Experiment at the Wolsong Nuclear Site
International Nuclear Information System (INIS)
Jeong, Hyojoon; Kim, Eunhan; Park, Misun; Jeong, Haesun; Hwang, Wontae; Han, Moonhee
2014-01-01
By comparing the concentration of a tracer measured under weather conditions that are disadvantageous to the dilution of radioactive materials released from the Wolsong Nuclear Power Plant, with the concentration of a tracer calculated using an air Dispersion model, it is possible to evaluate the characteristics of the air concentrations of radioactive materials estimated with an air Dispersion model, which can then be used in an environmental impact analysis of radioactive materials. Therefore, a field Dispersion experiment has been carried out to figure out the behavioral characteristics of the tracer under weather conditions that are disadvantageous to the dilution of radioactive materials released from the Wolsong Nuclear Power Plant site in Korea. In addition, through a comparison of the tracer concentrations estimated by the Gaussian plume model with measurements, this study checked the degree of conservative estimation for the Gaussian plume at the Wolsong nuclear site in Korea. A tracer Dispersion experiment using an SF 6 trace was implemented to determine the Dispersion characteristics of radioactive materials at the Wolsong Nuclear Power Plant site in Korea. Based on meteorological data and the emission rate of the tracers, this study estimated the tracer concentrations using a Gaussian plume model, and then compared it with the measurement to check the conservative estimation of the Gaussian plume model. The measured concentrations of the tracer tends to be lower than the concentrations estimated by the Gaussian plume model overall
Ryan, D. A.; Liu, Y. Q.; Li, L.; Kirk, A.; Dunne, M.; Dudson, B.; Piovesan, P.; Suttrop, W.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team
2017-02-01
Edge localised modes (ELMs) are a repetitive MHD instability, which may be mitigated or suppressed by the application of resonant magnetic perturbations (RMPs). In tokamaks which have an upper and lower set of RMP coils, the applied spectrum of the RMPs can be tuned for optimal ELM control, by introducing a toroidal phase difference {{Δ }}{{Φ }} between the upper and lower rows. The magnitude of the outermost resonant component of the RMP field | {b}{{res}}1| (other proposed criteria are discussed herein) has been shown experimentally to correlate with mitigated ELM frequency, and to be controllable by {{Δ }}{{Φ }} (Kirk et al 2013 Plasma Phys. Control. Fusion 53 043007). This suggests that ELM mitigation may be optimised by choosing {{Δ }}{{Φ }}={{Δ }}{{{Φ }}}{{opt}}, such that | {b}{{res}}1| is maximised. However it is currently impractical to compute {{Δ }}{{{Φ }}}{{opt}} in advance of experiments. This motivates this computational study of the dependence of the optimal coil phase difference {{Δ }}{{{Φ }}}{{opt}}, on global plasma parameters {β }N and q 95, in order to produce a simple parametrisation of {{Δ }}{{{Φ }}}{{opt}}. In this work, a set of tokamak equilibria spanning a wide range of ({β }N, q 95) is produced, based on a reference equilibrium from an ASDEX Upgrade experiment. The MARS-F code (Liu et al 2000 Phys. Plasmas 7 3681) is then used to compute {{Δ }}{{{Φ }}}{{opt}} across this equilibrium set for toroidal mode numbers n = 1-4, both for the vacuum field and including the plasma response. The computational scan finds that for fixed plasma boundary shape, rotation profiles and toroidal mode number n, {{Δ }}{{{Φ }}}{{opt}} is a smoothly varying function of ({β }N, q 95). A 2D quadratic function in ({β }N, q 95) is used to parametrise {{Δ }}{{{Φ }}}{{opt}}, such that for given ({β }N, q 95) and n, an estimate of {{Δ }}{{{Φ }}}{{opt}} may be made without requiring a plasma response computation. To quantify the uncertainty
A numerical study of HCCI combustion of PRF mixtures compared with PCCI experiments
Energy Technology Data Exchange (ETDEWEB)
Van Wijngaarden, B.
2008-09-15
For automotive applications engines that produce less soot and NOx are desired. For that reason the Homogeneous Charge Compression Ignition (HCCI) principle is investigated all over the world, including the technical universities of Berlin (TUB) and Eindhoven. HCCI combines a homogeneous charge, as in an Otto engine with the autoignition principle of a Diesel engine. Auto-ignition and almost instantaneous combustion of a homogeneous charge leads to almost zero soot emissions, lower temperatures and thereby much lower NOx emissions. Auto-ignition timing however, depends on the fuel and its chemistry, which is very sensitive to the applied conditions, being pressure, temperature, equivalence ratio ({phi}), dilution with EGR and engine speed. To study this systematically a 0D model with PRF fuels is used (Primary Reference Fuels are n-heptane, iso-octane and mixtures). A 0D model is chosen because it excludes complex fluid dynamics and thereby allows the use of detailed combustion mechanisms, describing the (PRF) chemistry. Furthermore the model has a multi zone possibility to evaluate in-homogeneities of the charge. PRF fuels are used because n-heptane (CN=55) auto-ignites like a diesel and iso-octane (ON=100) approaches gasoline. For the PRF chemistry three combustion mechanisms were selected, of which two were validated showing a great difference in predicted ignition delay and sensitivity to changes. Furthermore the model was validated with a PCCI (Premixed Charge Compression Ignition) experiment. Extensive comparisons with PCCI experiments from the TUB showed that when the moment of injection was used to launch the chemistry in the model, only the Soyhan mechanism predicted the ignition close to the experimental ignition moment. Furthermore a 7 zone model was able to approach the experimental CO and NOX emissions. Finally none of the mechanisms was able to predict a pressure profile similar to the experiments. More zones and or a better mechanism could improve
Wang, Ping; Pozdniakov, Sergey P.; Vasilevskiy, Peter Yu.
2017-12-01
Surface water infiltration from ephemeral dryland streams is particularly important in hyporheic exchange and biogeochemical processes in arid and semi-arid regions. However, streamflow transmission losses can vary significantly, partly due to spatiotemporal variations in streambed permeability. To extend our understanding of changes in streambed hydraulic properties, field investigations of streambed hydraulic conductivity were conducted in an ephemeral dryland stream in north-western China during high and low streamflow periods. Additionally, streamflow transmission losses were numerically estimated using combined stream and groundwater hydraulic head data and stream and streambed temperature data. An analysis of slug test data at two different river flow stages (one test was performed at a low river stage with clean water and the other at a high river stage with muddy water) suggested that sedimentation from fine-grained particles, i.e., physical clogging processes, likely led to a reduction in streambed hydraulic properties. To account for the effects of streambed clogging on changes in hydraulic properties, an iteratively increasing total hydraulic resistance during the slug test was considered to correct the estimation of streambed hydraulic conductivity. The stream and streambed temperature can also greatly influence the hydraulic properties of the streambed. One-dimensional coupled water and heat flux modelling with HYDRUS-1D was used to quantify the effects of seasonal changes in stream and streambed temperature on streamflow losses. During the period from 6 August 2014 to 4 June 2015, the total infiltration estimated using temperature-dependent hydraulic conductivity accounted for approximately 88% of that using temperature-independent hydraulic conductivity. Streambed clogging processes associated with fine particle settling/wash up cycles during flow events, and seasonal changes in streamflow temperature are two considerable factors that affect water
Numerical modelling of ICRF physics experiments in the Alcator C-mod tokamak
International Nuclear Information System (INIS)
Bonoli, P.T.; Boivin, R.L.; Brambilla, M.
2001-01-01
A full-wave spectral code (TORIC) has been used to simulate mode converted ion Bernstein wave (IBW) propagation and absorption for the first time at high poloidal mode number (-80< m<+80). Converged wave solutions for the mode converted wave are obtained in this limit and the predicted electron damping of the IBW is found to be consistent with experimental measurements from the Alcator C-Mod tokamak. The TORIC code has also been coupled to a bounce-averaged Fokker Planck module FPPRF and the combined codes are now run within the transport analysis tool TRANSP. This model was used to analyze off-axis hydrogen minority heating experiments in C-Mod where an internal transport barrier was obtained. (author)
Narula, Manmeet Singh
Innovative concepts using fast flowing thin films of liquid metals (like lithium) have been proposed for the protection of the divertor surface in magnetic fusion devices. However, concerns exist about the possibility of establishing the required flow of liquid metal thin films because of the presence of strong magnetic fields which can cause flow disrupting MHD effects. A plan is underway to design liquid lithium based divertor protection concepts for NSTX, a small spherical torus experiment at Princeton. Of these, a promising concept is the use of modularized fast flowing liquid lithium film zones, as the divertor (called the NSTX liquid surface module concept or NSTX LSM). The dynamic response of the liquid metal film flow in a spatially varying magnetic field configuration is still unknown and it is suspected that some unpredicted effects might be lurking. The primary goal of the research work being reported in this dissertation is to provide qualitative and quantitative information on the liquid metal film flow dynamics under spatially varying magnetic field conditions, typical of the divertor region of a magnetic fusion device. The liquid metal film flow dynamics have been studied through a synergic experimental and numerical modeling effort. The Magneto Thermofluid Omnibus Research (MTOR) facility at UCLA has been used to design several experiments to study the MHD interaction of liquid gallium films under a scaled NSTX outboard divertor magnetic field environment. A 3D multi-material, free surface MHD modeling capability is under development in collaboration with HyPerComp Inc., an SBIR vendor. This numerical code called HIMAG provides a unique capability to model the equations of incompressible MHD with a free surface. Some parts of this modeling capability have been developed in this research work, in the form of subroutines for HIMAG. Extensive code debugging and benchmarking exercise has also been carried out. Finally, HIMAG has been used to study the
Li, Y.; Ma, X.; Su, N.
2013-12-01
The movement of water and solute into and through the vadose zone is, in essence, an issue of immiscible displacement in pore-space network of a soil. Therefore, multiphase flow and transport in porous media, referring to three medium: air, water, and the solute, pose one of the largest unresolved challenges for porous medium fluid seepage. However, this phenomenon has always been largely neglected. It is expected that a reliable analysis model of the multi-phase flow in soil can truly reflect the process of natural movement about the infiltration, which is impossible to be observed directly. In such cases, geophysical applications of the nuclear magnetic resonance (NMR) provides the opportunity to measure the water movements into soils directly over a large scale from tiny pore to regional scale, accordingly enable it available both on the laboratory and on the field. In addition, the NMR provides useful information about the pore space properties. In this study, we proposed both laboratory and field experiments to measure the multi-phase flow parameters, together with optimize the model in computer programming based on the fractional partial differential equations (fPDE). In addition, we establish, for the first time, an infiltration model including solute flowing with water, which has huge influence on agriculture and soil environment pollution. Afterwards, with data collected from experiments, we simulate the model and analyze the spatial variability of parameters. Simulations are also conducted according to the model to evaluate the effects of airflow on water infiltration and other effects such as solute and absorption. It has significant meaning to oxygen irrigation aiming to higher crop yield, and shed more light into the dam slope stability. In summary, our framework is a first-time model added in solute to have a mathematic analysis with the fPDE and more instructive to agriculture activities.
Abel, Markus; Bodenschatz, Eberhard; Toschi, Federico
2011-12-01
Turbulent flows are ubiquitous in nature and technology. Turbulent flows govern the transport of particulate matter in nature. For example, in atmospheric flows turbulence impacts the dynamics of aerosols, droplets, spores and of the living world by either chemo-attractant transport or transport of the insects themselves. In marine flows examples include the bubble dynamics that governs the uptake of oxygen and carbon dioxide at the ocean air interface, or the impact of turbulence on the life of phyto- and zoo-plankton, or the spread of pollutants in the oceans and estuaries. Turbulence is equally important for technology from process engineering in chemical and pharmaceutical industries to energy transport and energy generation. The COST Action MP0806 'Particles in Turbulence' has as the primary objective the support of the fundamental research on the statistical properties of particle transport in turbulent flows. The Action provides excellent opportunities for the exchange of ideas by bringing together scientists from different areas of research and applications, or different views on the problem. The COST Action MP0806 organizes several events annually. The conference held at the University of Potsdam from 16 to 18 March 2011 was the main meeting of the Action in 2011. In total 87 researchers from 18 countries (of which 12 were European) met and presented their work, discussed new ideas on theoretical, numerical and experimental approaches, as well as on applications to various scientific domains. The conference attracted also a number of participants from outside the COST Action. The scientific presentations focused on inertial and finite-size particles, particle collisions, as well as advection and reaction in simple and complex flow geometries. Very interesting results were presented at the forefront of the field: the increasing computational power combined with novel numerical techniques now allows for the first time simulation of the dynamics of finites
Operational experience with the Sizewell B integrated plant computer system
International Nuclear Information System (INIS)
Ladner, J.E.J.; Alexander, N.C.; Fitzpatrick, J.A.
1997-01-01
The Westinghouse Integrated System for Centralised Operation (WISCO) is the primary plant control system at the Sizewell B Power Station. It comprises three subsystems; the High Integrity Control System (HICS), the Process Control System (PCS) and the Distributed Computer system (DCS). The HICS performs the control and data acquisition of nuclear safety significant plant systems. The PCS uses redundant data processing unit pairs. The workstations and servers of the DCS communicate with each other over a standard ethernet. The maintenance requirements for every plant system are covered by a Maintenance Strategy Report. The breakdown of these reports is listed. The WISCO system has performed exceptionally well. Due to the diagnostic information presented by the HICS, problems could normally be resolved within 24 hours. There have been some 200 outstanding modifications to the system. The procedure of modification is briefly described. (A.K.)
Experience with Intel's Many Integrated Core Architecture in ATLAS Software
Fleischmann, S; The ATLAS collaboration; Lavrijsen, W; Neumann, M; Vitillo, R
2014-01-01
Intel recently released the first commercial boards of its Many Integrated Core (MIC) Architecture. MIC is Intel's solution for the domain of throughput computing, currently dominated by general purpose programming on graphics processors (GPGPU). MIC allows the use of the more familiar x86 programming model and supports standard technologies such as OpenMP, MPI, and Intel's Threading Building Blocks. This should make it possible to develop for both throughput and latency devices using a single code base.\
Experience with Intel's Many Integrated Core Architecture in ATLAS Software
Fleischmann, S; The ATLAS collaboration; Lavrijsen, W; Neumann, M; Vitillo, R
2013-01-01
Intel recently released the first commercial boards of its Many Integrated Core (MIC) Architecture. MIC is Intel's solution for the domain of throughput computing, currently dominated by general purpose programming on graphics processors (GPGPU). MIC allows the use of the more familiar x86 programming model and supports standard technologies such as OpenMP, MPI, and Intel's Threading Building Blocks. This should make it possible to develop for both throughput and latency devices using a single code base.\
Integration of microbial biopesticides in greenhouse floriculture: The Canadian experience.
Brownbridge, Michael; Buitenhuis, Rose
2017-11-28
Historically, greenhouse floriculture has relied on synthetic insecticides to meet its pest control needs. But, growers are increasingly faced with the loss or failure of synthetic chemical pesticides, declining access to new chemistries, stricter environmental/health and safety regulations, and the need to produce plants in a manner that meets the 'sustainability' demands of a consumer driven market. In Canada, reports of thrips resistance to spinosad (Success™) within 6-12 months of its registration prompted a radical change in pest management philosophy and approach. Faced with a lack of registered chemical alternatives, growers turned to biological control out of necessity. Biological control now forms the foundation for pest management programs in Canadian floriculture greenhouses. Success in a biocontrol program is rarely achieved through the use of a single agent, though. Rather, it is realized through the concurrent use of biological, cultural and other strategies within an integrated plant production system. Microbial insecticides can play a critical supporting role in biologically-based integrated pest management (IPM) programs. They have unique modes of action and are active against a range of challenging pests. As commercial microbial insecticides have come to market, research to generate efficacy data has assisted their registration in Canada, and the development and adaptation of integrated programs has promoted uptake by floriculture growers. This review documents some of the work done to integrate microbial insecticides into chrysanthemum and poinsettia production systems, outlines current use practices, and identifies opportunities to improve efficacy in Canadian floriculture crops. Copyright © 2017 Elsevier Inc. All rights reserved.
CERCLA integration with site operations the Fernald experience
International Nuclear Information System (INIS)
Coyle, S.W.; Shirley, R.S.; Varchol, B.D.
1991-01-01
A major transition in the Fernald Environmental Management Project (FEMP) site mission has occurred over the past few years. The production capabilities formally provided by the FEMP are being transferred to private industry through a vendor qualification program. Environmental compliance and site cleanup are now the primary focus. In line with this program, the production of uranium products at the site was suspended in July 1989 in order to concentrate resources on the environmental mission. Formal termination of the FEMP production mission was accomplished on June 19, 1991. Environmental issues such as stored inventories of process residues materials and equipment are being addressed under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). The diversity of these hazards complicates the strategic planning for an integrated site cleanup program. The FEMP is one of the first Department of Energy (DOE) facilities to transition from an active production mission guided by Defense Programs (DP) to an environmental mission guided by Environmental Management (EM) under Leo Duffy. Westinghouse Environmental Management Company of Ohio (WEMCO) has been charged with integrating all site activities to carry out the cleanup. A new management structure has been formulated, and an integration approach initiated. Analyses are under way to evaluate all site activities such as waste management, safe shutdown, product material disposition and routine environmental monitoring in view of CERCLA requirements. Site activities are being broken down into three categories: (a) CERCLA driven - restoration work required under CERCLA, (b) CERCLA covered - other environmental requirements which must be integrated with CERCLA, and (c) CERCLA exempt (if any). The approach to comply with these categorized activities must be negotiated with state and federal regulatory agencies
Integral treatment of children with dyslexia - 40 years experience
Directory of Open Access Journals (Sweden)
Stošljević Miodrag
2012-01-01
Full Text Available Introduction. Dyslexia represents a significant pediatric problem requiring prompt and appropriate treatment. Objective. The aim of this study was to examine the significance of integral rehabilitation approach in treating dyslexia of children. Methods. Objectives of the study were accomplished on a sample of 300 children, aged 11-15 years, with etiologically variable dyslexia. Results. The results gained from the integral treatment of children with dyslexia were more successful than those obtained from isolated logaoedic treatment, when compared in 10-15 examined variables; replacement of graphically similar letters (p=0.000, replacement of syllables (p=0.010, replacement of words - guessing (p=0.019, structural errors - displacement or insertion (p=0.038, adding letters and syllables (p=0.001, repeating of word parts (p=0.001, reading of a word in several wrong ways (p=0.001, omission of words and whole lines (p=0.000, returning to already read line (p=0.000, level of dyslexia (p=0.000. Conclusion. Dyslexia requires a multidisciplinary therapeutic approach in which integral rehabilitation treatment has an exceptionally large significance.
Oskouie, M. Faraji; Ansari, R.; Rouhi, H.
2018-04-01
Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects. Previous studies have revealed that using the differential form of the strain-driven version of this theory leads to paradoxical results in some cases, such as bending analysis of cantilevers, and recourse must be made to the integral version. In this article, a novel numerical approach is developed for the bending analysis of Euler-Bernoulli nanobeams in the context of strain- and stress-driven integral nonlocal models. This numerical approach is proposed for the direct solution to bypass the difficulties related to converting the integral governing equation into a differential equation. First, the governing equation is derived based on both strain-driven and stress-driven nonlocal models by means of the minimum total potential energy. Also, in each case, the governing equation is obtained in both strong and weak forms. To solve numerically the derived equations, matrix differential and integral operators are constructed based upon the finite difference technique and trapezoidal integration rule. It is shown that the proposed numerical approach can be efficiently applied to the strain-driven nonlocal model with the aim of resolving the mentioned paradoxes. Also, it is able to solve the problem based on the strain-driven model without inconsistencies of the application of this model that are reported in the literature.
Numerical simulation of a liquid droplet combustion experiment focusing on ignition process
International Nuclear Information System (INIS)
Yamaguchi, Akira; Tajima, Yuji
1999-11-01
SPHINCS (Sodium Fire phenomenology IN multi-Cell System) computer program has been developed for the safety analysis of sodium fire accident in a Fast Breeder Reactor. The program can deal with spray combustion and pool surface combustion. In this report the authors investigate a single droplet combustion phenomena focusing on an ignition process. The spray combustion model of SPHINCS is as follows. The liquid droplet-burning rate after ignition is based on the D-square law and a diffusion flame assumption. Before the droplet is ignited, the burning rate is evaluated by mass flux of oxidizer gases. Forced convection effect that skews the sphere shape of the flame zone surrounding a droplet is taken into consideration. It enhances the burning rate. The chemical equilibrium theory is used to determine the resultant fraction of reaction products of Na-O 2 -H 2 O system. It is noted that users have to give an ignition temperature based on empirical evidences. According to this model, it is obvious that a smaller liquid droplet with higher initial temperature tends to burn more easily. What is observed in a recent experiment is that the smallest liquid droplet (2mm diameter) did not ignited of itself and larger droplets (3.7mm and 4.5mm diameter) burnt at 300degC initial temperature. The current model for liquid droplet combustion cannot predict the experimental results. Therefore, in the present study, a surface reaction model has been developed to predict the ignition process. The model has been used to analyze a combustion experiment of a stationary liquid droplet. The authors investigate the validity of the physical modeling of the liquid droplet combustion and surface reaction. It has been found, as the results, that the model can predict the influence of the initial temperature on the temperature lower limit for spontaneous ignition and ignition delay time. Also investigated is the influence of the moisture on the ignition phenomena. From the present study, it has
Energy Technology Data Exchange (ETDEWEB)
Kim, K. S.; Ju, H. G.; Jeon, T. H. and others
2005-03-15
A comprehensive high fidelity reactor core modeling capability has been developed for detailed analysis of current and advanced reactor designs as part of a US-ROK collaborative I-NERI project. High fidelity was accomplished by integrating highly refined solution modules for the coupled neutronic, thermal-hydraulic, and thermo-mechanical phenomena. Each solution module employs methods and models that are formulated faithfully to the first-principles governing the physics, real geometry, and constituents. Specifically, the critical analysis elements that are incorporated in the coupled code capability are whole-core neutron transport solution, ultra-fine-mesh computational fluid dynamics/heat transfer solution, and finite-element-based thermo-mechanics solution, all obtained with explicit (fuel pin cell level) heterogeneous representations of the components of the core. The vast computational problem resulting from such highly refined modeling is solved on massively parallel computers, and serves as the 'numerical nuclear reactor'. Relaxation of modeling parameters were also pursued to make problems run on clusters of workstations and PCs for smaller scale applications as well.
International Nuclear Information System (INIS)
Kim, K. S.; Ju, H. G.; Jeon, T. H. and others
2005-03-01
A comprehensive high fidelity reactor core modeling capability has been developed for detailed analysis of current and advanced reactor designs as part of a US-ROK collaborative I-NERI project. High fidelity was accomplished by integrating highly refined solution modules for the coupled neutronic, thermal-hydraulic, and thermo-mechanical phenomena. Each solution module employs methods and models that are formulated faithfully to the first-principles governing the physics, real geometry, and constituents. Specifically, the critical analysis elements that are incorporated in the coupled code capability are whole-core neutron transport solution, ultra-fine-mesh computational fluid dynamics/heat transfer solution, and finite-element-based thermo-mechanics solution, all obtained with explicit (fuel pin cell level) heterogeneous representations of the components of the core. The vast computational problem resulting from such highly refined modeling is solved on massively parallel computers, and serves as the 'numerical nuclear reactor'. Relaxation of modeling parameters were also pursued to make problems run on clusters of workstations and PCs for smaller scale applications as well
Nonaka, Andrew; Day, Marcus S.; Bell, John B.
2018-01-01
We present a numerical approach for low Mach number combustion that conserves both mass and energy while remaining on the equation of state to a desired tolerance. We present both unconfined and confined cases, where in the latter the ambient pressure changes over time. Our overall scheme is a projection method for the velocity coupled to a multi-implicit spectral deferred corrections (SDC) approach to integrate the mass and energy equations. The iterative nature of SDC methods allows us to incorporate a series of pressure discrepancy corrections naturally that lead to additional mass and energy influx/outflux in each finite volume cell in order to satisfy the equation of state. The method is second order, and satisfies the equation of state to a desired tolerance with increasing iterations. Motivated by experimental results, we test our algorithm on hydrogen flames with detailed kinetics. We examine the morphology of thermodiffusively unstable cylindrical premixed flames in high-pressure environments for confined and unconfined cases. We also demonstrate that our algorithm maintains the equation of state for premixed methane flames and non-premixed dimethyl ether jet flames.
International Nuclear Information System (INIS)
Ohwada, Hiroshi; Ishihara, Yasutoshi
2010-01-01
To improve the efficacy of hyperthermia treatment, a novel method of noninvasive measurement of body temperature change is proposed. The proposed technology, thermometry, is based on changes in the electromagnetic field distribution inside the heating applicator with temperature changes and the temperature dependence of the dielectric constant. In addition, an image of the temperature change distribution inside a body is reconstructed by applying a computed tomography (CT) algorithm. The proposed thermometry method can serve as a possible noninvasive method to monitor the temperature change distribution inside the body without the use of enormous thermometers such as in the case of magnetic resonance imaging (MRI). Furthermore, this temperature monitoring method can be easily combined with a heating applicator based on a cavity resonator, and the novel integrated treatment system can possibly be used to treat cancer effectively while noninvasively monitoring the heating effect. In this paper, the phase change distributions of the electromagnetic field with temperature changes are simulated by numerical analysis using the finite difference time domain (FDTD) method. Moreover, to estimate the phase change distributions inside a target body, the phase change distributions with temperature changes are reconstructed by a filtered back-projection. In addition, the reconstruction accuracy of the converted temperature change distribution from the phase change is evaluated. (author)
Šarolić, A; Živković, Z; Reilly, J P
2016-06-21
The electrostimulation excitation threshold of a nerve depends on temporal and frequency parameters of the stimulus. These dependences were investigated in terms of: (1) strength-duration (SD) curve for a single monophasic rectangular pulse, and (2) frequency dependence of the excitation threshold for a continuous sinusoidal current. Experiments were performed on the single-axon measurement setup based on Lumbricus terrestris having unmyelinated nerve fibers. The simulations were performed using the well-established SENN model for a myelinated nerve. Although the unmyelinated experimental model differs from the myelinated simulation model, both refer to a single axon. Thus we hypothesized that the dependence on temporal and frequency parameters should be very similar. The comparison was made possible by normalizing each set of results to the SD time constant and the rheobase current of each model, yielding the curves that show the temporal and frequency dependencies regardless of the model differences. The results reasonably agree, suggesting that this experimental setup and method of comparison with SENN model can be used for further studies of waveform effect on nerve excitability, including unmyelinated neurons.
Adaptive Core Simulation Employing Discrete Inverse Theory - Part II: Numerical Experiments
International Nuclear Information System (INIS)
Abdel-Khalik, Hany S.; Turinsky, Paul J.
2005-01-01
Use of adaptive simulation is intended to improve the fidelity and robustness of important core attribute predictions such as core power distribution, thermal margins, and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e., in-core instrumentation readings, to adapt the simulation in a meaningful way. The companion paper, ''Adaptive Core Simulation Employing Discrete Inverse Theory - Part I: Theory,'' describes in detail the theoretical background of the proposed adaptive techniques. This paper, Part II, demonstrates several computational experiments conducted to assess the fidelity and robustness of the proposed techniques. The intent is to check the ability of the adapted core simulator model to predict future core observables that are not included in the adaption or core observables that are recorded at core conditions that differ from those at which adaption is completed. Also, this paper demonstrates successful utilization of an efficient sensitivity analysis approach to calculate the sensitivity information required to perform the adaption for millions of input core parameters. Finally, this paper illustrates a useful application for adaptive simulation - reducing the inconsistencies between two different core simulator code systems, where the multitudes of input data to one code are adjusted to enhance the agreement between both codes for important core attributes, i.e., core reactivity and power distribution. Also demonstrated is the robustness of such an application
Hutson, Elizabeth
2018-01-01
The emotional experience of bullying victimization in youths has been documented primarily using quantitative methods; however, qualitative methods may be better suited to examine the experience. An integrative review of the qualitative method studies addressing the emotional experience of bullying victimization was conducted. From MEDLINE,…
Numerical Simulations of Counter Current Flow Experiments Using a Morphology Detection Algorithm
Directory of Open Access Journals (Sweden)
Thomas Höhne
2012-09-01
Full Text Available In order to improve the understanding of counter-current two-phase flows and to validate new physical models, CFD simulations of 1/3rd scale model of the hot leg of a German Konvoi PWR with rectangular cross section was performed. Selected counter-current flow limitation (CCFL experiments at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR were calculated with ANSYS CFX 12.1 using the multi-fluid Euler-Euler modeling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a SST turbulence model for each phase. In the simulation, the surface drag was approached by a new correlation inside the Algebraic Interfacial Area Density (AIAD model. The AIAD model allows the detection of the morphological form of the two phase flow and the corresponding switching via a blending function of each correlation from one object pair to another. As a result this model can distinguish between bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicated that quantitative agreement of the CCFL characteristics between calculation and experimental data was obtained. To validate the model and to study scaling effects CFD simulations of the CCFL phenomenon in a full scale PWR hot leg of the UPTF test facility were performed. Also these results indicated a good agreement between the calculation and experimental data. The final goal is to provide an easy usable AIAD framework for all ANSYS CFX users, with the possibility of the implementation of their own correlations.
Enhancing user experience design with an integrated storytelling method
Peng, Qiong; Matterns, Jean Bernard; Marcus, A.
2016-01-01
Storytelling has been known as a service design method and been used broadly not only in service design but also in the context of user experience design. However, practitioners cannot yet fully appreciate the benefits of storytelling, and often confuse storytelling with storyboarding and scenarios.
An Integral, Multidisciplinary and Global Geophysical Field Experience for Undergraduates
Vázquez, O.; Carrillo, D. J.; Pérez-Campos, X.
2007-05-01
The udergraduate program of Geophysical Engineering at the School of Engineering, of the Univesidad Nacional Autónoma de México (UNAM), went through an update process that concluded in 2006. As part of the program, the student takes three geophysical prospecting courses (gravity and magnetics, electric, electromagnetics, and seismic methods). The older program required a three-week field experience for each course in order to gradute. The new program considers only one extended field experience. This work stresses the importance of international academic exchange, where undergraduate students could participate, such as the Summer of Applied Geophysical Experience (SAGE), and interaction with research programs, such as the MesoAmerican Subduction Experiment (MASE). Also, we propose a scheeme for this activity based on those examples; both of them have in common real geophysical problems, from which students could benefit. Our proposal covers academic and logistic aspects to be taken into account, enhancing the relevance of interaction between other academic institutions, industry, and UNAM, in order to obtain a broader view of geophysics.
The Developmental Impact of Not Integrating Childhood Peak Experiences
Schlarb, Craig W.
2007-01-01
Much prior groundbreaking research has been done in recent years highlighting the qualities, quantities and means children have to enter transpersonal states of awareness. As important as this precedent research has been, in many ways it has yet to fully appreciate the gravity of childhood transpersonal experiences in terms of the impact on…
CERCLA integration with site operations the Fernald experience
International Nuclear Information System (INIS)
Coyle, S.W.; Shirley, R.S.; Varchol, B.D.
1991-01-01
A major transition in the Fernald Environmental Management Project (FEMP) site mission has occurred over the past few years. The production capabilities formally provided by the FEMP are being transferred to private industry through a vendor qualification program. Environmental compliance and site cleanup are now the primary focus. In line with this program, the production of uranium products at the site was suspended in July 1989 in order to concentrate resources on the environmental mission. Formal termination of the FEMP production mission was accomplished on June 19, 1991. Environmental issues such as stored inventories of process residues materials and equipment are being addressed under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). The diversity of these hazards complicates the strategic planning for an integrated site cleanup program. This paper will discuss the programmatic approach which is being implemented to ensure activities such as waste management, site utility and support services, health and safety programs, and Resource Conservation and Recovery Act (RCRA) programs are being integrated with CERCLA. 6 figs., 3 tabs
Lessons learned: Experiences with Integrated Safeguards in Norway
International Nuclear Information System (INIS)
Sekse, T.; Hornkjol, S.
2010-01-01
Integrated safeguards (IS) was implemented in Norway in 2002 as one of the first countries in the world. The implementation of IS has provided both advantages and disadvantages for Norway. Lessons learned will be discussed. The concept of unannounced inspections under the integrated safeguards regime compared to traditional safeguards is one of the major issues. Small users with depleted uranium as shielding containers and the effort used to safeguard them is an aspect of this issue. Recently there has been an interest from the IAEA to investigate the historical boundaries between a research reactor site and a neighboring defense research site. The paper will address this issue as a part of the implementation of IS. Lately, we have seen that several commercial parties have started research on nuclear fuel cycle related projects. This raises some questions concerning what to declare under Article 2 of the Additional Protocol (AP). Today anyone with a computer connected to the internet could carry out research amenable to declaration under the AP. This paper will discuss this issue. (author)
Numerical experiments on plasma focus for soft x-ray yield scaling laws derivation using Lee model
International Nuclear Information System (INIS)
Akel, M.
2015-01-01
The required plasma parameters of krypton and xenon at different temperatures were calculated, the x-ray emission properties of plasmas were studied, and based on the corona model the suitable temperature range for generating H-like and He-like ions (therefore soft x-ray emissions) of different gases plasma were found. The code is applied to characterize the plasma focus in different plasma focus devices, and for optimizing the nitrogen, oxygen, neon, argon, krypton and xenon soft x-ray yields based on bank, tubes and operating parameters. It is found that t he soft x-ray yield increases with changing pressure until it reaches the maximum value for each plasma focus device. Keeping the bank parameters, operational voltage unchanged but systematically changing other parameters, numerical experiments were performed finding the optimum combination of Po, z0 and 'a' for the maximum soft x-ray yield. Thus we expect to increase the soft x-ray yield of plasma focus device several-fold from its present typical operation; without changing the capacitor bank, merely by changing the electrode configuration and the operating pressure. The Lee model code was also used to run numerical experiments on plasma focus devices for optimizing soft x-ray yield with reducing Lo, varying z0 and 'a' to get engineering designs with maximum soft x-ray yield for these devices at different experimental conditions and gases. Numerical experiments showed the influence of the gas used in plasma focus and its propor ties on soft x-ray emission and its propor ties and then on its applications. Scaling laws for soft x-ray of nitrogen, oxygen, neon, argon, krypton and xenon plasma focus in terms of energy, peak discharge current and focus pinch current were found. Radiative cooling effects are studied indicating that radiative collapse may be observed for heavy noble gases (Ar, Kr, Xe) for pinch currents even below 100 k A. The results show that the line radiation emission and
Numerical experiments on plasma focus for soft x-ray yield scaling laws derivation using Lee model
International Nuclear Information System (INIS)
Akel, M.
2012-09-01
The required plasma parameters of krypton and xenon at different temperatures were calculated, the x-ray emission properties of plasmas were studied, and based on the corona model the suitable temperature range for generating H-like and He-like ions (therefore soft x-ray emissions) of different gases plasma were found. The code is applied to characterize the plasma focus in different plasma focus devices, and for optimizing the nitrogen, oxygen, neon, argon, krypton and xenon soft x-ray yields based on bank, tubes and operating parameters. It is found that the soft x-ray yield increases with changing pressure until it reaches the maximum value for each plasma focus device. Keeping the bank parameters, operational voltage unchanged but systematically changing other parameters, numerical experiments were performed finding the optimum combination of P o , Z o and 'a' for the maximum soft x-ray yield. Thus we expect to increase the soft x-ray yield of plasma focus device several-fold from its present typical operation; without changing the capacitor bank, merely by changing the electrode configuration and the operating pressure. The Lee model code was also used to run numerical experiments on plasma focus devices for optimizing soft x-ray yield with reducing L o , varying L o and 'a' to get engineering designs with maximum soft x-ray yield for these devices at different experimental conditions and gases. Numerical experiments showed the influence of the gas used in plasma focus and its properties on soft x-ray emission and its properties and then on its applications. Scaling laws for soft x-ray of nitrogen, oxygen, neon, argon, krypton and xenon plasma focus, in terms of energy, peak discharge current and focus pinch current were found. Radiative cooling effects are studied indicating that radiative collapse may be observed for heavy noble gases (Ar, Kr, Xe) for pinch currents even below 100 kA. The results show that the line radiation emission and tube voltages have
Driving behavioural change towards ecodesign integration: Nudging experiment in industry
DEFF Research Database (Denmark)
Brones, Fabien; Gyldendal Melberg, Morten; Monteiro de Carvalho, Marly
2014-01-01
This paper describes a research study conducted at Natura, a large Brazilian cosmetic company, in order to stimulate more systematic sustainable innovation practices by means of behavioural change. Within the “soft side” of ecodesign implementation, “nudging” is a novel approach brought from soci...... systemically consider individuals’ engagement, including behavioural aspects, interaction with project teams and higher level business organisations.......This paper describes a research study conducted at Natura, a large Brazilian cosmetic company, in order to stimulate more systematic sustainable innovation practices by means of behavioural change. Within the “soft side” of ecodesign implementation, “nudging” is a novel approach brought from social...... sciences and policy making. An empirical experiment identified and tested employee motivations in combination with behavioural influences, in order to positively affect employees’ intention to practice ecodesign. This original experience of green nudging in a private company context supported the diffusion...
Driving behavioural change towards ecodesign integration: Nudging experiment in industry
Brones, Fabien; Gyldendal Melberg, Morten; Monteiro de Carvalho, Marly; Pigosso, Daniela Cristina Antelmi; McAloone, Tim C.
2014-01-01
This paper describes a research study conducted at Natura, a large Brazilian cosmetic company, in order to stimulate more systematic sustainable innovation practices by means of behavioural change. Within the “soft side” of ecodesign implementation, “nudging” is a novel approach brought from social sciences and policy making. An empirical experiment identified and tested employee motivations in combination with behavioural influences, in order to positively affect employees’ intention to prac...
A Regional Integrated Virtual Learning Environment: The AOU's Experience
Directory of Open Access Journals (Sweden)
Said Hammad
2004-02-01
Full Text Available In this paper we propose to construct a Regional Integrated Virtual Learning Environment (RIVLE for the Arab Open University (AOU. AOU is a new nonprofit learning institution with branches in six Arab countries and more branches scheduled to open in the near future. The university adopts an open learning methodology. We describe the major elements of the RIVLE and their interaction. We present a generic interface between the RIVLE and the Student Information System (SIS. We focus on the characteristics of the pedagogical model in the Arab Open University context and explain why RIVLE would be a perfect fit for this model. We argue that the potential benefits of a RIVLE are realized in such a setting. We also study the possibility of extending the RIVLE to existing learning institutions in the region.
Review of Integral Experiments for Minor Actinide Management
International Nuclear Information System (INIS)
Gil, C.S.; Glinatsis, G.; Hesketh, K.; Iwamoto, O.; Okajima, S.; Tsujimoto, K.; Jacqmin, R.; Khomyakov, Y.; Kochetkov, A.; Kormilitsyn, M.; Palmiotti, G.; Salvatores, M.; Perret, G.; Rineiski, A.; Romanello, V.; Sweet, D.
2015-01-01
Spent nuclear fuel contains minor actinides (MAs) such as neptunium, americium and curium, which require careful management. This becomes even more important when mixed oxide (MOX) fuel is being used on a large scale since more MAs will accumulate in the spent fuel. One way to manage these MAs is to transmute them in nuclear reactors, including in light water reactors, fast reactors or accelerator-driven subcritical systems. The transmutation of MAs, however, is not straightforward, as the loading of MAs generally affects physics parameters, such as coolant void, Doppler and burn-up reactivity. This report focuses on nuclear data requirements for minor actinide management, the review of existing integral data and the determination of required experimental work, the identification of bottlenecks and possible solutions, and the recommendation of an action programme for international co-operation. (authors)
Directory of Open Access Journals (Sweden)
Eric Asaba
2017-01-01
Full Text Available Background. Occupational therapists sometimes find it challenging to integrate client-centered and occupational therapy specific assessments in practice. The aim of this study was to explore the use of occupational therapy specific assessments such as the Assessment of Motor and Process Skills (AMPS among occupational therapists in Sweden and Japan. Methods. Interviews and qualitative thematic analyses were utilized. Findings. Four themes are reported: (1 use it or lose it, (2 simply no space until after hours, (3 biggest barriers can be colleagues, and (4 being more specific: communication. Conclusion. In keeping with previous studies, occupational therapists often find it challenging to implement client-centered and occupation-based assessment tools into practice. However, more work is needed to understand how best practices can be incorporated into a changing occupational therapy daily practice.
Corver, M.P.; Doust, H.; van Wees, J.D.A.M.; Cloetingh, S.A.P.L.
2011-01-01
We present the results of an integrated analogue and numerical modeling study with a focus on structural, stratigraphic and thermal differences between symmetric and asymmetric grabens. These models enable fault interpretation and subsidence analyses in studies of active rifting and graben
International Nuclear Information System (INIS)
Kostroun, V.O.
1980-01-01
Theoretical expressions for the angular and spectral distributions of synchrotron radiation involve modified Bessel functions of fractional order and the integral ∫sup(infinitely)sub(x)Ksub(ν)(eta)d eta. A simple series expression for these quantities which can be evaluated numerically with hand-held programmable calculators is presented. (orig.)
International Nuclear Information System (INIS)
Fronteau, J.; Combis, P.
1984-08-01
A Lagrangian method is introduced for the integration of non-linear Fokker-Planck equations. Examples of exact solutions obtained in this way are given, and also the explicit scheme used for the computation of numerical solutions. The method is, in addition, shown to be of a Lie-admissible type
International Nuclear Information System (INIS)
Liang, Xian-Ting
2014-01-01
A framework for simulating electronic spectra from photon-echo experiments is constructed by using a numerical path integral technique. This method is non-Markovian and nonperturbative and, more importantly, is not limited by a fixed form of the spectral density functions of the environment. Next, a two-dimensional (2D) third-order electronic spectrum of a dimer system is simulated. The spectrum is in agreement with the experimental and theoretical results previously reported [for example, M. Khalil, N. Demirdöven, and A. Tokmakoff, Phys. Rev. Lett. 90, 047401 (2003)]. Finally, a 2D third-order electronic spectrum of the Fenna-Matthews-Olson (FMO) complex is simulated by using the Debye, Ohmic, and Adolphs and Renger spectral density functions. It is shown that this method can clearly produce the spectral signatures of the FMO complex by using only the Adolphs and Renger spectral density function. Plots of the evolution of the diagonal and cross-peaks show that they are oscillating with the population time
International Nuclear Information System (INIS)
Li Hsuennien; Ferng Yuhming; Shih Chunkuan; Hsu Wensheng
2007-01-01
FDS [1] code numerically solves a form of the Navier-Stokes equations appropriate for low-speed, thermally driven flow with an emphasis on smoke and heat transport from fires. FDS uses a mixture fraction combustion model. The mixture fraction is a conserved scalar quantity that is defined as the fraction of fuel gas at a given point in the flow field. The model assumes that combustion is mixing-controlled, and that the reaction of fuel and oxygen is infinitely fast. In FDS, Lagrangian particles are used to simulate smoke movement and sprinkling water-mist discharge. In order to evaluate the combustion model and water-mist suppression function of the code, FDS analyses are conducted to simulate two enclosure fire cases available in the literature. Comparisons with other combustion models are also made. For fires suppression by water-mist in FDS, parametric studies are performed to compare various water-mist injection characteristics for maximum suppression. Numerical results indicate that the flame suppression is closely related to characteristics of the water mist, such as droplet diameter, mist injection velocity, injection density. Our present investigations show that the combustion model and water-mist suppression in FDS can provide simulation results that are comparable with the experiments. (author)
Krejsa, M.; Brozovsky, J.; Mikolasek, D.; Parenica, P.; Koubova, L.
2018-04-01
The paper is focused on the numerical modeling of welded steel bearing elements using commercial software system ANSYS, which is based on the finite element method - FEM. It is important to check and compare the results of FEM analysis with the results of physical verification test, in which the real behavior of the bearing element can be observed. The results of the comparison can be used for calibration of the computational model. The article deals with the physical test of steel supporting elements, whose main purpose is obtaining of material, geometry and strength characteristics of the fillet and butt welds including heat affected zone in the basic material of welded steel bearing element. The pressure test was performed during the experiment, wherein the total load value and the corresponding deformation of the specimens under the load was monitored. Obtained data were used for the calibration of numerical models of test samples and they are necessary for further stress and strain analysis of steel supporting elements.
International Nuclear Information System (INIS)
Nishi, Y; Inagaki, T; Li, Y; Omiya, R; Hatano, K
2014-01-01
The purpose of this research is to develop a water turbine appropriate for low-head open channels in order to effectively utilize the unused hydropower energy of rivers and agricultural waterways. The application of the cross-flow runner to open channels as an undershot water turbine has come under consideration and, to this end, a significant simplification was attained by removing the casings. However, the flow field of undershot cross-flow water turbines possesses free surfaces. This means that with the variation in the rotational speed, the water depth around the runner will change and flow field itself is significantly altered. Thus it is necessary to clearly understand the flow fields with free surfaces in order to improve the performance of this turbine. In this research, the performance of this turbine and the flow field were studied through experiments and numerical analysis. The experimental results on the performance of this turbine and the flow field were consistent with the numerical analysis. In addition, the inlet and outlet regions at the first and second stages of this water turbine were clarified
Time-integrated CP violation measurements in the B mesons system at the LHCb experiment
Cardinale, R
2016-01-01
Time-integrated CP violation measurements in the B meson system provide information for testing the CKM picture of CP violation in the Standard Model. A review of recent results from the LHCb experiment is presented.