Numerical optimization of conical flow waveriders including detailed viscous effects
Bowcutt, Kevin G.; Anderson, John D., Jr.; Capriotti, Diego
1987-01-01
A family of optimized hypersonic waveriders is generated and studied wherein detailed viscous effects are included within the optimization process itself. This is in contrast to previous optimized waverider work, wherein purely inviscid flow is used to obtain the waverider shapes. For the present waveriders, the undersurface is a streamsurface of an inviscid conical flowfield, the upper surface is a streamsurface of the inviscid flow over a tapered cylinder (calculated by the axisymmetric method of characteristics), and the viscous effects are treated by integral solutions of the boundary layer equations. Transition from laminar to turbulent flow is included within the viscous calculations. The optimization is carried out using a nonlinear simplex method. The resulting family of viscous hypersonic waveriders yields predicted high values of lift/drag, high enough to break the L/D barrier based on experience with other hypersonic configurations. Moreover, the numerical optimization process for the viscous waveriders results in distinctly different shapes compared to previous work with inviscid-designed waveriders. Also, the fine details of the viscous solution, such as how the shear stress is distributed over the surface, and the location of transition, are crucial to the details of the resulting waverider geometry. Finally, the moment coefficient variations and heat transfer distributions associated with the viscous optimized waveriders are studied.
Generalized Database Management System Support for Numeric Database Environments.
Dominick, Wayne D.; Weathers, Peggy G.
1982-01-01
This overview of potential for utilizing database management systems (DBMS) within numeric database environments highlights: (1) major features, functions, and characteristics of DBMS; (2) applicability to numeric database environment needs and user needs; (3) current applications of DBMS technology; and (4) research-oriented and…
Scilab and Maxima Environment: Towards Free Software in Numerical Analysis
Mora, Angel; Galan, Jose Luis; Aguilera, Gabriel; Fernandez, Alvaro; Merida, Enrique; Rodriguez, Pedro
2010-01-01
In this work we will present the ScilabUMA environment we have developed as an alternative to Matlab. This environment connects Scilab (for numerical analysis) and Maxima (for symbolic computations). Furthermore, the developed interface is, in our opinion at least, as powerful as the interface of Matlab. (Contains 3 figures.)
Including the Consumer and Environment in Occupational Therapy Treatment Planning.
Brown, Catana; Bowen, Robin E.
1998-01-01
Occupational therapists (n=29) completed treatment plans based on case study data. Analysis indicated they often identified goals not addressed by the consumer/client. They significantly selected more simulated than real activities and more activities designed to change the person rather than the environment. (SK)
Gas Adsorption in Novel Environments, Including Effects of Pore Relaxation
International Nuclear Information System (INIS)
Cole, Milton W; Gatica, Silvina M; Kim, Hye-Young; Lueking, Angela D; Sircar, Sarmishtha
2012-01-01
Adsorption experiments have been interpreted frequently with simplified model geometries, such as ideally flat surfaces and slit or cylindrical pores. Recent explorations of unusual environments, such as fullerenes and metal-organic-framework materials, have led to a broadened scope of experimental, theoretical and simulation investigations. This paper reviews a number of such studies undertaken by our group. Among the topics receiving emphasis are these: universality of gas uptake in pores, relaxation of a porous absorbent due to gas uptake and the novel phases of gases on a single nanotube, all of which studies have been motivated by recent experiments.
Expanding Health Technology Assessments to Include Effects on the Environment
DEFF Research Database (Denmark)
Marsh, Kevin; Ganz, Michael Lee; Hsu, John
2016-01-01
decision makers. Health care is an important and sizable sector of the economy that could warrant closer policy attention to its impact on the environment. Considerable work is needed to track decision makers' demands, augment the environmental evidence base, and develop robust methods for capturing......There is growing awareness of the impact of human activity on the climate and the need to stem this impact. Public health care decision makers from Sweden and the United Kingdom have started examining environmental impacts when assessing new technologies. This article considers the case...... and objectives extending beyond health care. Two types of challenges hinder this process. First, the nascent evidence base is insufficient to support the accurate comparison of technologies' environmental impacts. Second, cost-utility analysis, which is favored by many HTA agencies, could capture some...
Expanding Health Technology Assessments to Include Effects on the Environment.
Marsh, Kevin; Ganz, Michael L; Hsu, John; Strandberg-Larsen, Martin; Gonzalez, Raquel Palomino; Lund, Niels
2016-01-01
There is growing awareness of the impact of human activity on the climate and the need to stem this impact. Public health care decision makers from Sweden and the United Kingdom have started examining environmental impacts when assessing new technologies. This article considers the case for incorporating environmental impacts into the health technology assessment (HTA) process and discusses the associated challenges. Two arguments favor incorporating environmental impacts into HTA: 1) environmental changes could directly affect people's health and 2) policy decision makers have broad mandates and objectives extending beyond health care. Two types of challenges hinder this process. First, the nascent evidence base is insufficient to support the accurate comparison of technologies' environmental impacts. Second, cost-utility analysis, which is favored by many HTA agencies, could capture some of the value of environmental impacts, especially those generating health impacts, but might not be suitable for addressing broader concerns. Both cost-benefit and multicriteria decision analyses are potential methods for evaluating health and environmental outcomes, but are less familiar to health care decision makers. Health care is an important and sizable sector of the economy that could warrant closer policy attention to its impact on the environment. Considerable work is needed to track decision makers' demands, augment the environmental evidence base, and develop robust methods for capturing and incorporating environmental data as part of HTA. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Numerical Treatment of Two-phase Flow in Porous Media Including Specific Interfacial Area
El-Amin, Mohamed
2015-06-01
In this work, we present a numerical treatment for the model of two-phase flow in porous media including specific interfacial area. For numerical discretization we use the cell-centered finite difference (CCFD) method based on the shifting-matrices method which can reduce the time-consuming operations. A new iterative implicit algorithm has been developed to solve the problem under consideration. All advection and advection-like terms that appear in saturation equation and interfacial area equation are treated using upwind schemes. Selected simulation results such as pc–Sw–awn surface, capillary pressure, saturation and specific interfacial area with various values of model parameters have been introduced. The simulation results show a good agreement with those in the literature using either pore network modeling or Darcy scale modeling.
Numerical Analysis of Thermal Comfort at Urban Environment
Papakonstantinou, K.; Belias, C.
2009-08-01
The present paper refers to the numerical simulation of air velocity at open air spaces and the conducting thermal comfort after the evaluation of the examined space using CFD methods, taking into account bioclimatic principles at the architectural design. More specially, the paper draws attention to the physical procedures governing air movement at an open environment area in Athens (athletic park), named "Serafeio Athletic and Cultural Centre," trying to form them in such way that will lead to the thermal comfort of the area's visitors. The study presents a mathematical model, implemented in a general computer code that can provide detailed information on velocity, prevailing in three-dimensional spaces of any geometrical complexity. Turbulent flow is simulated and buoyancy effects are taken into account. This modelling procedure is intended to contribute to the effort towards designing open areas, such as parks, squares or outdoor building environments, using thermal comfort criteria at the bioclimatic design. A computer model of this kind will provide the architects or the environmental engineers with powerful and economical means of evaluating alternative spaces' designs.
A numerical model including PID control of a multizone crystal growth furnace
Panzarella, Charles H.; Kassemi, Mohammad
1992-01-01
This paper presents a 2D axisymmetric combined conduction and radiation model of a multizone crystal growth furnace. The model is based on a programmable multizone furnace (PMZF) designed and built at NASA Lewis Research Center for growing high quality semiconductor crystals. A novel feature of this model is a control algorithm which automatically adjusts the power in any number of independently controlled heaters to establish the desired crystal temperatures in the furnace model. The control algorithm eliminates the need for numerous trial and error runs previously required to obtain the same results. The finite element code, FIDAP, used to develop the furnace model, was modified to directly incorporate the control algorithm. This algorithm, which presently uses PID control, and the associated heat transfer model are briefly discussed. Together, they have been used to predict the heater power distributions for a variety of furnace configurations and desired temperature profiles. Examples are included to demonstrate the effectiveness of the PID controlled model in establishing isothermal, Bridgman, and other complicated temperature profies in the sample. Finally, an example is given to show how the algorithm can be used to change the desired profile with time according to a prescribed temperature-time evolution.
Ortleb, Sigrun; Seidel, Christian
2017-07-01
In this second symposium at the limits of experimental and numerical methods, recent research is presented on practically relevant problems. Presentations discuss experimental investigation as well as numerical methods with a strong focus on application. In addition, problems are identified which require a hybrid experimental-numerical approach. Topics include fast explicit diffusion applied to a geothermal energy storage tank, noise in experimental measurements of electrical quantities, thermal fluid structure interaction, tensegrity structures, experimental and numerical methods for Chladni figures, optimized construction of hydroelectric power stations, experimental and numerical limits in the investigation of rain-wind induced vibrations as well as the application of exponential integrators in a domain-based IMEX setting.
International Nuclear Information System (INIS)
Yamazawa, H.; Ohkura, T.; Iida, T.; Chino, M.; Nagai, H.
2003-01-01
Main functions of the Numerical Environment System (NES), as a part of the Information Technology Based Laboratory (ITBL) project implemented by Japan Atomic Energy Research Institute, became available for test use purposes although the development of the system is still underway. This system consists of numerical models of meteorology and atmospheric dispersion, database necessary for model simulations, post- and pre-processors such as data conversion and visualization, and a suite of system software which provide the users with system functions through a web page access. The system utilizes calculation servers such as vector- and scalar-parallel processors for numerical model execution, a EWS which serves as a hub of the system. This system provides users in the field of nuclear emergency preparedness and atmospheric environment with easy-to-use functions of atmospheric dispersion simulations including input meteorological data preparation and visualization of simulation results. The performance of numerical models in the system was examined with observation data of long-range transported radon-222. The models in the system reproduced quite well temporal variations in the observed radon-222 concentrations in air which were caused by changes in the meteorological field in the synoptic scale. By applying the NES models in combination with the idea of backward-in-time atmospheric dispersion simulation, seasonal shift of source areas of radon-222 in the eastern Asian regions affecting the concentrations in Japan was quantitatively illustrated. (authors)
A novel method of including Landau level mixing in numerical studies of the quantum Hall effect
International Nuclear Information System (INIS)
Wooten, Rachel; Quinn, John; Macek, Joseph
2013-01-01
Landau level mixing should influence the quantum Hall effect for all except the strongest applied magnetic fields. We propose a simple method for examining the effects of Landau level mixing by incorporating multiple Landau levels into the Haldane pseudopotentials through exact numerical diagonalization. Some of the resulting pseudopotentials for the lowest and first excited Landau levels will be presented
International Nuclear Information System (INIS)
Amirkhizi, Alireza V; Nemat-Nasser, Sia
2008-01-01
Through the use of conductive straight wires or coils the electromagnetic properties of a composite material can be modified. The asymmetric geometry of the coils creates an overall chiral response. The polarization vectors rotate as an electromagnetic wave travels through such a medium. To calculate the chirality of a medium prior to its manufacturing, we developed a method to extract all four electromagnetic material parameter tensors for a general uniaxial bianisotropic composite based on the numerical simulation of the electromagnetic fields. Our method uses appropriate line and surface field averages in a single unit cell of the periodic structure of the composite material. These overall field quantities have physical meaning only when the microscopic variation of the electromagnetic fields in the scale of the unit cell is not important, that is when the wavelength of interest is significantly larger than the maximum linear dimension of the unit cell. The overall constitutive relations of the periodic structure can then be obtained from the relations among the average quantities
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
DEFF Research Database (Denmark)
Rasmussen, Anders Rønne; Sørensen, Mads Peter; Gaididei, Yuri Borisovich
2010-01-01
A wave equation, that governs finite amplitude acoustic disturbances in a thermoviscous Newtonian fluid, and includes nonlinear terms up to second order, is proposed. The equation preserves the Hamiltonian structure of the fundamental fluid dynamical equations in the non dissipative limit. An exact...... thermoviscous shock solution is derived. This solution is, in an overall sense, equivalent to the Taylor shock solution of the Burgers equation. However, in contrast to the Burgers equation, the model equation considered here is capable to describe waves propagating in opposite directions. Studies of head...
Directory of Open Access Journals (Sweden)
Kuligowska Ewa
2017-06-01
Full Text Available The material given in this paper delivers the procedure for numerical approach that allows finding the main practically important safety characteristics of the complex technical systems at the variable operation conditions including operating environment threats. The obtained results are applied to the safety evaluation of the maritime ferry technical system. It is assumed that the conditional safety functions are different at various operation states and have the exponential forms. Using the procedure and the program written in Mathematica, the considered maritime ferry technical system main characteristics including: the conditional and the unconditional expected values and standard deviations of the system lifetimes, the unconditional safety function and the risk function are determined.
Research status and some results of numerical system to study regional environment: SPEEDI-MP
International Nuclear Information System (INIS)
Chino, Masamichi
2004-01-01
Research status and some results of 'Numerical system to study regional environment: SPEEDI-MP', which reproduces circulations of materials in the atmospheric, oceanic and terrestrial environments, are introduced. The purpose of this system are the development of various environmental models, the connection of atmospheric, oceanic and terrestrial models and the construction of research bases for numerical environmental studies. In addition to the accurate prediction of environmental behavior of radionuclides, the system has been applied to the non-nuclear fields, e.g., numerical analysis of environmental effects to volcanic gases from Miyake Jima, real-time prediction of the migration of rice planthoppers from Eastern Asia. (author)
Numerical study of the propagation of high power microwave pulses in air breakdown environment
International Nuclear Information System (INIS)
Kim, J.; Kuo, S.P.
1992-01-01
A theoretical model based on a set of two modal equations has been developed to describe self-consistently the propagation of an intense microwave pulse in an air breakdown environment. It includes Poynting's equation for the continuity of the power flux of the pulse and the rate equation of the electron density. A forward wave approximation is used to simplify Poynting's equation and a semi-empirical formula for the ionization frequency as a function of the wave field amplitude is adopted for this model. In order to improve the numerical efficiency of the model in terms of the required computation time and available subroutines for numerical analysis of pulse propagation over a long distance, a transformation to the frame of local time of the pulse is introduced. The effect of space-time dependence of the group velocity of the pulse is included in this properly designed transformation. The inhomogeneous feature of the background pressure is also preserved in the model. The resultant equations are reduced to the forms which can be solved directly by the available subroutine of ODE solver. In this work, a comprehensive numerical analysis of the propagation of high power microwave pulse through the atmosphere is performed. It is shown that the pulse energy can severely be attenuated by the self-generated plasma. Therefore, the aim of the present study is to identify the optimum parameters of the pulse so that the energy loss of the pulse before reaching the destination can be minimized. These parameters include the power, frequency, shape and length of the pulse. The conditions for maximizing the ionization at a destinated region in the upper atmosphere will also be determined
Ratto, Luca; Satta, Francesca; Tanda, Giovanni
2018-06-01
This paper presents an experimental and numerical investigation of heat transfer in the endwall region of a large scale turbine cascade. The steady-state liquid crystal technique has been used to obtain the map of the heat transfer coefficient for a constant heat flux boundary condition. In the presence of two- and three-dimensional flows with significant spatial variations of the heat transfer coefficient, tangential heat conduction could lead to error in the heat transfer coefficient determination, since local heat fluxes at the wall-to-fluid interface tend to differ from point to point and surface temperatures to be smoothed out, thus making the uniform-heat-flux boundary condition difficult to be perfectly achieved. For this reason, numerical simulations of flow and heat transfer in the cascade including the effect of tangential heat conduction inside the endwall have been performed. The major objective of numerical simulations was to investigate the influence of wall heat conduction on the convective heat transfer coefficient determined during a nominal iso-flux heat transfer experiment and to interpret possible differences between numerical and experimental heat transfer results. Results were presented and discussed in terms of local Nusselt number and a convenient wall heat flux function for two values of the Reynolds number (270,000 and 960,000).
Kołowrocki, Krzysztof; Kuligowska, Ewa; Soszyńska-Budny, Joanna
2017-01-01
The paper presents an integrated general model of complex technical system, linking its multistate safety model and the model of its operation process including operating environment threats and considering variable at different operation states its safety structures and its components safety parameters. Under the assumption that the system has exponential safety function, the safety characteristics of the port oil piping transportation system are determined.
Christ, Andreas; Thews, Oliver
2016-04-01
Mathematical models are suitable to simulate complex biological processes by a set of non-linear differential equations. These simulation models can be used as an e-learning tool in medical education. However, in many cases these mathematical systems have to be treated numerically which is computationally intensive. The aim of the study was to develop a system for numerical simulation to be used in an online e-learning environment. In the software system the simulation is located on the server as a CGI application. The user (student) selects the boundary conditions for the simulation (e.g., properties of a simulated patient) on the browser. With these parameters the simulation on the server is started and the simulation result is re-transferred to the browser. With this system two examples of e-learning units were realized. The first one uses a multi-compartment model of the glucose-insulin control loop for the simulation of the plasma glucose level after a simulated meal or during diabetes (including treatment by subcutaneous insulin application). The second one simulates the ion transport leading to the resting and action potential in nerves. The student can vary parameters systematically to explore the biological behavior of the system. The described system is able to simulate complex biological processes and offers the possibility to use these models in an online e-learning environment. As far as the underlying principles can be described mathematically, this type of system can be applied to a broad spectrum of biomedical or natural scientific topics. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Kołowrocki Krzysztof
2017-06-01
Full Text Available The paper presents an integrated general model of complex technical system, linking its multistate safety model and the model of its operation process including operating environment threats and considering variable at different operation states its safety structures and its components safety parameters. Under the assumption that the system has exponential safety function, the safety characteristics of the port oil piping transportation system are determined.
Directory of Open Access Journals (Sweden)
Natasha A. Layton
2015-09-01
Full Text Available Contemporary discourses which challenge the notion of health as the “absence of disease” are prompting changes in health policy and practice. People with disability have been influential in progressing our understanding of the impact of contextual factors in individual and population health, highlighting the impact of environmental factors on functioning and inclusion. The World Health Organization’s (WHO more holistic definition of health as “wellbeing” is now applied in frameworks and legislation, and has long been understood in occupational therapy theory. In practice, however, occupational therapists and other professionals often address only local and individual environmental factors to promote wellbeing, within systems and societies that limit equity in population health and restrict inclusion in communities. This paper presents an in-depth analysis of the supports and accommodations identified by a cohort of individuals (n-100 living with disability. A range of environmental facilitators and barriers were identified in peoples’ experience of “inclusive community environs” and found to influence inclusion and wellbeing. The roles and responsibilities of individuals, professionals, and society to enact change in environments are discussed in light of these findings. Recommendations include a focus on the subjective experience of environments, and application of theory from human rights and inclusive economics to address the multiple dimensions and levels of environments in working towards inclusion and wellbeing.
An analytically based numerical method for computing view factors in real urban environments
Lee, Doo-Il; Woo, Ju-Wan; Lee, Sang-Hyun
2018-01-01
A view factor is an important morphological parameter used in parameterizing in-canyon radiative energy exchange process as well as in characterizing local climate over urban environments. For realistic representation of the in-canyon radiative processes, a complete set of view factors at the horizontal and vertical surfaces of urban facets is required. Various analytical and numerical methods have been suggested to determine the view factors for urban environments, but most of the methods provide only sky-view factor at the ground level of a specific location or assume simplified morphology of complex urban environments. In this study, a numerical method that can determine the sky-view factors ( ψ ga and ψ wa ) and wall-view factors ( ψ gw and ψ ww ) at the horizontal and vertical surfaces is presented for application to real urban morphology, which are derived from an analytical formulation of the view factor between two blackbody surfaces of arbitrary geometry. The established numerical method is validated against the analytical sky-view factor estimation for ideal street canyon geometries, showing a consolidate confidence in accuracy with errors of less than 0.2 %. Using a three-dimensional building database, the numerical method is also demonstrated to be applicable in determining the sky-view factors at the horizontal (roofs and roads) and vertical (walls) surfaces in real urban environments. The results suggest that the analytically based numerical method can be used for the radiative process parameterization of urban numerical models as well as for the characterization of local urban climate.
Parker, Tim; Devanney, Peter; Bainbridge, Geoff; Townsend, Bruce
2017-04-01
The march to make every type of seismometer, weak to strong motion, reliable and economically deployable in any terrestrial environment continues with the availability of three new sensors and seismic systems including ones with over 200dB of dynamic range. Until recently there were probably 100 pier type broadband sensors for every observatory type pier, not the types of deployments geoscientists are needing to advance science and monitoring capability. Deeper boreholes are now the recognized quieter environments for best observatory class instruments and these same instruments can now be deployed in direct burial environments which is unprecedented. The experiences of facilities in large deployments of broadband seismometers in continental scale rolling arrays proves the utility of packaging new sensors in corrosion resistant casings and designing in the robustness needed to work reliably in temporary deployments. Integrating digitizers and other sensors decreases deployment complexity, decreases acquisition and deployment costs, increases reliability and utility. We'll discuss the informed evolution of broadband pier instruments into the modern integrated field tools that enable economic densification of monitoring arrays along with supporting new ways to approach geoscience research in a field environment.
McGillivary, P. A.; Borges de Sousa, J.; Wackowski, S.; Walker, G.
2011-12-01
Small remotely piloted aircraft have recently been used for maritime remote sensing, including launch and retrieval operations from land, ships and sea ice. Such aircraft can also function to collect and communicate data from other ocean observing system platforms including moorings, tagged animals, drifters, autonomous surface vessels (ASVs), and autonomous underwater vessels (AUVs). The use of small remotely piloted aircraft (or UASs, unmanned aerial systems) with a combination of these capabilities will be required to monitor the vast areas of the open ocean, as well as in harsh high-latitude ecosystems. Indeed, these aircraft are a key component of planned high latitude maritime domain awareness environmental data collection capabilities, including use of visible, IR and hyperspectral sensors, as well as lidar, meteorological sensors, and interferometric synthetic aperture radars (ISARs). We here first describe at-sea demonstrations of improved reliability and bandwidth of communications from ocean sensors on autonomous underwater vehicles to autonomous surface vessels, and then via remotely piloted aircraft to shore, ships and manned aircraft using Delay and Disruption Tolerant (DTN) communication protocols. DTN enables data exchange in communications-challenged environments, such as remote regions of the ocean including high latitudes where low satellite angles and auroral disturbances can be problematic. DTN provides a network architecture and application interface structured around optionally-reliable asynchronous message forwarding, with limited expectations of end-to-end connectivity and node resources. This communications method enables aircraft and surface vessels to function as data mules to move data between physically disparate nodes. We provide examples of the uses of this communication protocol for environmental data collection and data distribution with a variety of different remotely piloted aircraft in a coastal ocean environment. Next, we
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.
Directory of Open Access Journals (Sweden)
Andrea Lani
2006-01-01
Full Text Available Object-oriented platforms developed for the numerical solution of PDEs must combine flexibility and reusability, in order to ease the integration of new functionalities and algorithms. While designing similar frameworks, a built-in support for high performance should be provided and enforced transparently, especially in parallel simulations. The paper presents solutions developed to effectively tackle these and other more specific problems (data handling and storage, implementation of physical models and numerical methods that have arisen in the development of COOLFluiD, an environment for PDE solvers. Particular attention is devoted to describe a data storage facility, highly suitable for both serial and parallel computing, and to discuss the application of two design patterns, Perspective and Method-Command-Strategy, that support extensibility and run-time flexibility in the implementation of physical models and generic numerical algorithms respectively.
Music for All: Including young people with intellectual disability in a university environment.
Rickson, Daphne; Warren, Penny
2017-01-01
We investigated a continuing education course in creative music making, initiated to promote the inclusion of young people with intellectual disability in a university setting. Despite organizers' attempts to foster diversity within the student cohort, enrolments were almost exclusively from students who had intellectual disability. Being in the university environment, and in a place of higher learning, seemed to be valued by some. However, students' main focus was on group musicking in a dedicated music room rather than interacting with the wider university community. Those who did not identify as disabled believed it was important to continue to address the barriers to wider inclusion. While acknowledging the risks around mediating the social interactions of young people with intellectual disability, we argue that future courses should include activities specifically designed to bring them to classes with typical students and to the wider activities of the university.
Challenges for Life Support Systems in Space Environments, Including Food Production
Wheeler, Raymond M.
2012-01-01
Environmental Control and Life Support Systems (ECLSS) refer to the technologies needed to sustain human life in space environments. Histor ically these technologies have focused on providing a breathable atmo sphere, clean water, food, managing wastes, and the associated monitoring capabilities. Depending on the space agency or program, ELCSS has sometimes expanded to include other aspects of managing space enviro nments, such as thermal control, radiation protection, fire detection I suppression, and habitat design. Other times, testing and providing these latter technologies have been associated with the vehicle engi neering. The choice of ECLSS technologies is typically driven by the mission profile and their associated costs and reliabilities. These co sts are largely defined by the mass, volume, power, and crew time req uirements. For missions close to Earth, e.g., low-Earth orbit flights, stowage and resupply of food, some 0 2, and some water are often the most cost effective option. But as missions venture further into spa ce, e.g., transit missions to Mars or asteroids, or surface missions to Moon or Mars, the supply line economics change and the need to clos e the loop on life support consumables increases. These are often ref erred to as closed loop or regenerative life support systems. Regardless of the technologies, the systems must be capable of operating in a space environment, which could include micro to fractional g setting s, high radiation levels, and tightly closed atmospheres, including perhaps reduced cabin pressures. Food production using photosynthetic o rganisms such as plants by nature also provides atmospheric regenerat ion (e.g., CO2 removal and reduction, and 0 2 production), yet to date such "bioregenerative" technologies have not been used due largely t o the high power requirements for lighting. A likely first step in te sting bioregenerative capabilities will involve production of small a mounts of fresh foods to supplement to crew
International Nuclear Information System (INIS)
Garratt, T.J.
1989-05-01
Compartment models for the transport of radionuclides in the biosphere are conventionally solved using a numerical time-stepping procedure. This report examines an alternative method based on the numerical inversion of Laplace transforms, which is potentially more efficient and accurate for some classes of problem. The central problem considered is the most efficient and robust technique for solving the Laplace-transformed rate equations. The conclusion is that Gaussian elimination is the most efficient and robust solution method. A general compartment model has been implemented on a personal computer and used to solve a realistic case including radionuclide decay chains. (author)
DEFF Research Database (Denmark)
Rasmussen, Filip Salling; Sonne, Mads Rostgaard; Larsen, Martin
In the present study, a two-dimensional (2D) transient Eulerian thermo-chemical analysis of a carbon fibre epoxy thermosetting Resin Injection Pultrusion (RIP) process is carried out. The numerical model is implemented using the well known unconditionally stable Alternating Direction Implicit (ADI......) scheme. The total heat of reaction and the cure kinetics of the epoxy thermosetting are determined using Differential Scanning Calorimetry (DSC). A very good agreement is observed between the fitted cure kinetic model and the experimental measurements. The numerical steady state temperature predictions...
DEFF Research Database (Denmark)
Sonne, Mads Rostgaard; Carlone, Pierpaolo; Palazzo, Gaetano S.
2014-01-01
In the present paper, a numerical finite element model of the precipitation hardenable AA2024-T3 aluminum alloy, consisting of a heat transfer analysis based on the Thermal Pseudo Mechanical model for heat generation, and a sequentially coupled quasi-static stress analysis is proposed. Metallurgi...
Energy Technology Data Exchange (ETDEWEB)
Ames, Forrest [Univ. of North Dakota, Grand Forks, ND (United States); Bons, Jeffrey [Univ. of North Dakota, Grand Forks, ND (United States)
2014-09-30
The Department of Energy has goals to move land based gas turbine systems to alternate fuels including coal derived synthetic gas and hydrogen. Coal is the most abundant energy resource in the US and in the world and it is economically advantageous to develop power systems which can use coal. Integrated gasification combined cycles are (IGCC) expected to allow the clean use of coal derived fuels while improving the ability to capture and sequester carbon dioxide. These cycles will need to maintain or increase turbine entry temperatures to develop competitive efficiencies. The use of coal derived syngas introduces a range of potential contaminants into the hot section of the gas turbine including sulfur, iron, calcium, and various alkali metals. Depending on the effectiveness of the gas clean up processes, there exists significant likelihood that the remaining materials will become molten in the combustion process and potentially deposit on downstream turbine surfaces. Past evidence suggests that deposition will be a strong function of increasing temperature. Currently, even with the best gas cleanup processes a small level of particulate matter in the syngas is expected. Consequently, particulate deposition is expected to be an important consideration in the design of turbine components. The leading edge region of first stage vanes most often have higher deposition rates than other areas due to strong fluid acceleration and streamline curvature in the vicinity of the surface. This region remains one of the most difficult areas in a turbine nozzle to cool due to high inlet temperatures and only a small pressure ratio for cooling. The leading edge of a vane often has relatively high heat transfer coefficients and is often cooled using showerhead film cooling arrays. The throat of the first stage nozzle is another area where deposition potentially has a strongly adverse effect on turbine performance as this region meters the turbine inlet flow. Based on roughness
Bagshaw, Andrew T M; Horwood, L John; Fergusson, David M; Gemmell, Neil J; Kennedy, Martin A
2017-02-03
The genetic and environmental influences on human personality and behaviour are a complex matter of ongoing debate. Accumulating evidence indicates that short tandem repeats (STRs) in regulatory regions are good candidates to explain heritability not accessed by genome-wide association studies. We tested for associations between the genotypes of four selected repeats and 18 traits relating to personality, behaviour, cognitive ability and mental health in a well-studied longitudinal birth cohort (n = 458-589) using one way analysis of variance. The repeats were a highly conserved poly-AC microsatellite in the upstream promoter region of the T-box brain 1 (TBR1) gene and three previously studied STRs in the activating enhancer-binding protein 2-beta (AP2-β) and androgen receptor (AR) genes. Where significance was found we used multiple regression to assess the influence of confounding factors. Carriers of the shorter, most common, allele of the AR gene's GGN microsatellite polymorphism had fewer anxiety-related symptoms, which was consistent with previous studies, but in our study this was not significant following Bonferroni correction. No associations with two repeats in the AP2-β gene withstood this correction. A novel finding was that carriers of the minor allele of the TBR1 AC microsatellite were at higher risk of conduct problems in childhood at age 7-9 (p = 0.0007, which did pass Bonferroni correction). Including maternal smoking during pregnancy (MSDP) in models controlling for potentially confounding influences showed that an interaction between TBR1 genotype and MSDP was a significant predictor of conduct problems in childhood and adolescence (p behaviour up to age 25 years (p ≤ 0.02). This interaction remained significant after controlling for possible confounders including maternal age at birth, socio-economic status and education, and offspring birth weight. The potential functional importance of the TBR1 gene's promoter microsatellite
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)
A systematic review including meta-analysis of work environment and depressive symptoms.
Theorell, Töres; Hammarström, Anne; Aronsson, Gunnar; Träskman Bendz, Lil; Grape, Tom; Hogstedt, Christer; Marteinsdottir, Ina; Skoog, Ingmar; Hall, Charlotte
2015-08-01
Depressive symptoms are potential outcomes of poorly functioning work environments. Such symptoms are frequent and cause considerable suffering for the employees as well as financial loss for the employers. Accordingly good prospective studies of psychosocial working conditions and depressive symptoms are valuable. Scientific reviews of such studies have pointed at methodological difficulties but still established a few job risk factors. Those reviews were published some years ago. There is need for an updated systematic review using the GRADE system. In addition, gender related questions have been insufficiently reviewed. Inclusion criteria for the studies published 1990 to June 2013: 1. European and English speaking countries. 2. Quantified results describing the relationship between exposure (psychosocial or physical/chemical) and outcome (standardized questionnaire assessment of depressive symptoms or interview-based clinical depression). 3. Prospective or comparable case-control design with at least 100 participants. 4. Assessments of exposure (working conditions) and outcome at baseline and outcome (depressive symptoms) once again after follow-up 1-5 years later. 5. Adjustment for age and adjustment or stratification for gender. Studies filling inclusion criteria were subjected to assessment of 1.) relevance and 2.) quality using predefined criteria. Systematic review of the evidence was made using the GRADE system. When applicable, meta-analysis of the magnitude of associations was made. Consistency of findings was examined for a number of possible confounders and publication bias was discussed. Fifty-nine articles of high or medium high scientific quality were included. Moderately strong evidence (grade three out of four) was found for job strain (high psychological demands and low decision latitude), low decision latitude and bullying having significant impact on development of depressive symptoms. Limited evidence (grade two) was shown for psychological
International Nuclear Information System (INIS)
Mumovic, D.; Crowther, J.M.; Stevanovic, Z.
2003-01-01
Since 1950 the world population has more than doubled but meanwhile the global number of cars has increased by a factor of 10. In that same period the fraction of people living in urban areas has increased by a factor of 4. Apart from large point-sources of local air pollution, traffic induced pollution is now the most significant contributor to urban air quality in city centres, particularly for carbon monoxide, oxides of nitrogen and fine particulate matter. Until recently, pollutant dispersion in urban areas has usually been numerically investigated by using empirical models, such as the Gaussian plume model, or by extensions of this technique to line sources and multiple sources. More recently, advanced computational fluid dynamics (CFD) simulations have been attempted but have been mainly two-dimensional and often encompassing only a single street canyon. This paper provides a comprehensive, critical evaluation of dispersion of pollutants in urban areas. A three-dimensional flow model has been set-up for a staggered crossroad, using the Navier-Stokes equations and the conservation equation for species concentration. The effect of using several different turbulence models, including the k-ε model, modifications and extensions, has been investigated. Cartesian coordinates have been used in connection with the Partial Solution Algorithm (PARSOL) and Body Fitted Coordinates (BFC). The effects of several different numerical algorithms for discretization of differential equations have also been studied. More than thirty cases are analysed, and the main results are compared with wind tunnel experiments. The numerical results are presented as non-dimensional values to facilitate comparison between experimental and numerical studies. It has been shown that the numerical studies have been able to simulate the air-flow in urban areas and confirm, qualitatively, the previous field observations and wind tunnel results. This success encouraged the authors to extend such
Energy Technology Data Exchange (ETDEWEB)
Mumovic, D.; Crowther, J.M. [Glasgow Caledonian Univ., School of Built and Natural Environment, Glasgow (United Kingdom)]. E-mail: dmumov10@caledonian.ac.uk; Stevanovic, Z. [Univ. of Belgrade, Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro)
2003-07-01
Since 1950 the world population has more than doubled but meanwhile the global number of cars has increased by a factor of 10. In that same period the fraction of people living in urban areas has increased by a factor of 4. Apart from large point-sources of local air pollution, traffic induced pollution is now the most significant contributor to urban air quality in city centres, particularly for carbon monoxide, oxides of nitrogen and fine particulate matter. Until recently, pollutant dispersion in urban areas has usually been numerically investigated by using empirical models, such as the Gaussian plume model, or by extensions of this technique to line sources and multiple sources. More recently, advanced computational fluid dynamics (CFD) simulations have been attempted but have been mainly two-dimensional and often encompassing only a single street canyon. This paper provides a comprehensive, critical evaluation of dispersion of pollutants in urban areas. A three-dimensional flow model has been set-up for a staggered crossroad, using the Navier-Stokes equations and the conservation equation for species concentration. The effect of using several different turbulence models, including the k-{epsilon} model, modifications and extensions, has been investigated. Cartesian coordinates have been used in connection with the Partial Solution Algorithm (PARSOL) and Body Fitted Coordinates (BFC). The effects of several different numerical algorithms for discretization of differential equations have also been studied. More than thirty cases are analysed, and the main results are compared with wind tunnel experiments. The numerical results are presented as non-dimensional values to facilitate comparison between experimental and numerical studies. It has been shown that the numerical studies have been able to simulate the air-flow in urban areas and confirm, qualitatively, the previous field observations and wind tunnel results. This success encouraged the authors to extend
Effect of pressurized water reactor environment on fatigue crack propagation, including hole times
International Nuclear Information System (INIS)
Bamford, W.H.
1976-01-01
Results are presented from an experimental program being conducted to investigate the effects of pressurized water reactor environment on the fatigue crack growth rate of pressure vessel steels. Tests were conducted on precracked WOL type specimens under load controlled conditions. The effects of R ratio, loading rates, and loading wave form are evaluated, and the results are compared for both forging and plate material, as well as weldments
Rhazi, Dilal
In the field of aeronautics, reducing the harmful effects of acoustics constitutes a major concern at the international level and justifies the call for further research, particularly in Canada where aeronautics is a key economic sector, which operates in a context of global competition. Aircraft sidewall structure is usually of a double wall construction with a curved ribbed metallic skin and a lightweight composite or sandwich trim separated by a cavity filled with a noise control treatment. The latter is of a great importance in the transport industry, and continues to be of interest in many engineering applications. However, the insertion loss noise control treatment depends on the excitation of the supporting structure. In particular, Turbulent Boundary Layer is of interest to several industries. This excitation is difficult to simulate in laboratory conditions, given the prohibiting costs and difficulties associated with wind tunnel and in-flight tests. Numerical simulation is the only practical way to predict the response to such excitations and to analyze effects of design changes to the response to such excitation. Another kinds of excitations encountered in industrial are monopole, rain on the Roof and diffuse acoustic field. Deterministic methods can calculate in each point the spectral response of the system. Most known are numerical methods such as finite elements and boundary elements methods. These methods generally apply to the low frequency where modal behavior of the structure dominates. However, the high limit of calculation in frequency of these methods cannot be defined in a strict way because it is related to the capacity of data processing and to the nature of the studied mechanical system. With these challenges in mind, and with limitations of the main numerical codes on the market, the manufacturers have expressed the need for simple models immediately available as early as the stage of preliminary drafts. This thesis represents an attempt
Numerical study of dispersing pollutant clouds in a built-up environment
International Nuclear Information System (INIS)
Wang Bingchen; Yee, Eugene; Lien, F.-S.
2009-01-01
In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-ε turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-ε models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)
Numerical study of dispersing pollutant clouds in a built-up environment
Energy Technology Data Exchange (ETDEWEB)
Wang Bingchen [Department of Mechanical and Manufacturing Engineering, University of Manitoba, 75A Chancellors Circle, Winnipeg, Manitoba, R3T 5V6 (Canada)], E-mail: bc_wang@umanitoba.ca; Yee, Eugene [Defence Research and Development Canada - Suffield, P.O. Box 4000, STN Main, Medicine Hat, AB, T1A 8K6 (Canada)], E-mail: eugene.yee@drdc-rddc.gc.ca; Lien, F.-S. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: fslien@mecheng1.uwaterloo.ca
2009-02-15
In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-{epsilon} turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-{epsilon} models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)
Energy Technology Data Exchange (ETDEWEB)
Ozolin, Y.E.; Karol, I.L. [Main Geophysical Observatory, St. Petersburg (Russian Federation); Ramaroson, R. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)
1997-12-31
Box model for coupled gaseous and aqueous phases is used for sensitivity study of potential transformation of trace gases in a cloud environment. The rate of this transformation decreases with decreasing of pH in droplets, with decreasing of photodissociation rates inside the cloud and with increasing of the droplet size. Model calculations show the potential formation of H{sub 2}O{sub 2} in aqueous phase and transformation of gaseous HNO{sub 3} into NO{sub x} in a cloud. This model is applied for exploration of aircraft exhausts evolution in plume inside a cloud. (author) 10 refs.
Energy Technology Data Exchange (ETDEWEB)
Ozolin, Y E; Karol, I L [Main Geophysical Observatory, St. Petersburg (Russian Federation); Ramaroson, R [Office National d` Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)
1998-12-31
Box model for coupled gaseous and aqueous phases is used for sensitivity study of potential transformation of trace gases in a cloud environment. The rate of this transformation decreases with decreasing of pH in droplets, with decreasing of photodissociation rates inside the cloud and with increasing of the droplet size. Model calculations show the potential formation of H{sub 2}O{sub 2} in aqueous phase and transformation of gaseous HNO{sub 3} into NO{sub x} in a cloud. This model is applied for exploration of aircraft exhausts evolution in plume inside a cloud. (author) 10 refs.
Kolandaivelu, K. P.; Lowell, R. P.
2015-12-01
To better understand the effects of anhydrite precipitation on mid-ocean ridge hydrothermal systems, we conducted 2-D numerical simulations of two-phase hydrothermal circulation in a NaCl-H2O fluid at the East Pacific Rise 9°50'N. The simulations were constrained by key observational thermal data and seismicity that suggests the fluid flow is primarily along axis with recharge focused into a small zone near a 4th order discontinuity. The simulations considered an open-top square box with a fixed seafloor pressure of 25 MPa, and nominal seafloor temperature of 10 °C. The sides of the box were assumed to be impermeable and insulated. We considered two models: a homogeneous model with a permeability of 10-13 m2 and a heterogeneous model in which layer 2A extrusives were given a higher permeability. Both models had a fixed bottom temperature distribution and initial porosity of 0.1. Assuming that anhydrite precipitation resulted from the decrease in solubility with increasing temperature as downwelling fluid gets heated, we calculated the rate of porosity decrease and sealing times in each cell at certain time snapshots in the simulations. The results showed that sealing would occur most rapidly in limited regions near the base of the high-temperature plumes, where complete sealing could occur on decadal time scales. Though more detailed analysis is needed, it appeared that the areas of rapid sealing would likely have negligible impact on the overall circulation pattern and hydrothermal vent temperatures. The simulations also indicated that sealing due to anhydrite precipitation would occur more slowly at the margins of the ascending plumes. The sealing times in the deep recharge zone determined in these simulations were considerably greater than estimated from 1D analytical calculations, suggesting that with a 2D model, focused recharge at the EPR 9°50'N site may occur, at least on a decadal time scale.
Utility of sea snakes as bio-indicators for diverse marine environments including coral reefs
DEFF Research Database (Denmark)
Redsted Rasmussen, Arne
2016-01-01
be a valuable tool to accomplish this goal. Recent research shows that a group of sea snakes (the sea kraits Laticauda spp.) specialised on eels as prey, bears the promise of being useful bio-indicators for surveying the Anguilliform fish (eel like fish) in coral reefs(Brischoux, Bonnet, & Legagneux, 2009...... including coral reefs. Choosing sea snakes as bio-indicators in a broader sense is not possible with the present knowledge on the group today. It is therefore most needed to get more knowledge on sea snake biology to make it possible to use them as marine indicator species to measure e.g. biodiversity...
International Nuclear Information System (INIS)
Nagata, A.; Ashida, H.; Okamoto, M.; Hirano, K.
1981-03-01
Two dimentional fluid simulation code ''TOPICS'' is developed for the STP-2, the shock heated screw pinch at Nagoya. It involves the effects of impurity ions and neutral atoms. In order to estimate the radiation losses, the impurity continuity equations with ionizations and recombinations are solved simultaneously with the plasma fluid equations. The results are compared with the coronal equilibrium model. It is found that the coronal equilibrium model underestimates the radiation losses from shock heated pinch plasmas in its initial dynamic phase. The present calculations including impurities and neutrals show the importance of the radiation losses from the plasma of the STP-2. Introducing the anomalous resistivity caused by the ion acoustic instability, the observed magnetic field penetration is explained fairly well. (author)
Numerical Simulation of Blast Action on Civil Structures in Urban Environment
Valger, Svetlana A.; Fedorova, Natalya N.; Fedorov, Alexander V.
2017-10-01
Nowadays, a lot of industrial accidents accompanied by explosions are happening throughout the world. Also, increase in the number of terrorist acts committed by means of explosions is observed. For improving safety of buildings and structures it is necessary to raise their resistance to explosive effects, as well as to be able to predict degree of potential damage upon explosive loads of various intensities. One of the principal goals in designing the structure resistant to explosive effects is to determine the dynamic response of structures to the impact of the blast wave. To this end, the transient pressure loads on the walls of the civil engineering structures are to be determined. The simulation of explosion is highly complicated, involving an explosion causing the shock wave propagation in air and then interaction with a structure. The engineering-level techniques permit one to estimate an explosive shock impact only for isolated buildings. The complexity of the building, the presence of nearby structures and the surrounding environment cannot be taken into account. Advanced computer aid engineering (CAE) software techniques combined with the latest methods of discrete three-dimensional city modelling permits one to simulate and analyse the effects of explosions in urban areas with a precision which previously was not possible. In the paper, the simulation results are presented of shock wave forming due to a spherical explosive charge and its propagation in the vicinity of geometrical configuration imitating an urban environment. The numerical simulation of a flow in the vicinity of prisms of different cross-sections and heights located on a flat plate was performed. The calculations are carried out in a three-dimensional non-viscous formulation using ANSYS software. On a basis of simulation results, a complex wave structures were analysed, and all the peculiarities of flows and pressure history records on building walls were described and explained. The
Herrador-Alcaide, Teresa Carmen; Hernández-Solís, Montserrat
2017-01-01
The purpose of this study was to analyse the perceived usefulness of a set of Information and Communication Technologies (ICT) applied in a virtual learning environment (VLE) in a distance education model. We analysed whether the numerical and technological preferences of the students could explain the perceived usefulness related to the ICT…
International Nuclear Information System (INIS)
Lateb, M.; Meroney, R.N.; Yataghene, M.; Fellouah, H.; Saleh, F.; Boufadel, M.C.
2016-01-01
This article deals with the state-of-the-art of experimental and numerical studies carried out regarding air pollutant dispersion in urban environments. Since the simulation of the dispersion field around buildings depends strongly on the correct simulation of the wind-flow structure, the studies performed during the past years on the wind-flow field around buildings are reviewed. This work also identifies errors that can produce poor results when numerically modelling wind flow and dispersion fields around buildings in urban environments. Finally, particular attention is paid to the practical guidelines developed by researchers to establish a common methodology for verification and validation of numerical simulations and/or to assist and support the users for a better implementation of the computational fluid dynamics (CFD) approach. - This review article enlightens the reader on the use of CFD for pollutant dispersion. Errors that induce poor results and critical parameters that compromise significantly the accuracy and reliability are identified.
Collier, Richard S.; McKenna, Paul M.; Perala, Rodney A.
1991-08-01
The objective here is to describe the lightning hazards to buildings and their internal environments using advanced formulations of Maxwell's Equations. The method described is the Three Dimensional Finite Difference Time Domain Solution. It can be used to solve for the lightning interaction with such structures in three dimensions with the inclusion of a considerable amount of detail. Special techniques were developed for including wire, plumbing, and rebar into the model. Some buildings have provisions for lightning protection in the form of air terminals connected to a ground counterpoise system. It is shown that fields and currents within these structures can be significantly high during a lightning strike. Time lapse video presentations were made showing the electric and magnetic field distributions on selected cross sections of the buildings during a simulated lightning strike.
International Nuclear Information System (INIS)
Saint-Pierre, S.; RPWG
2008-01-01
This paper updates the WNA key messages on the RP of the environment. This paper shows that the chronology of views (2000-2008) leads to a recognition that the current RP system has provided adequate protection of people and of the environment. In early 2000s, doubts were raised on the adequacy of the RP system. Next (2002-2005), the international community forged the view that the current RP system has in practice provided appropriate standards of environmental protection, but also acknowledged that the system needs further development to fill a 'conceptual gap'. In 2005, the IAEA plan of activities on the RP of the environment formalized international developments and conditioned the future revision (if any) of current standards. During 2006-2008, ICRP issued new guidance on RP of non-human species which offers little on an assessment framework of practical use and on a compelling case for such assessments. This guidance, based on the new ICRP concept of Reference Animals and Plants, falls short in terms of environmental protection approach. A milestone study on the RP of non-human species is the SENES independent overview (2007) which 'confirmed that both people and nature have been adequately protected from radioactive releases from all kinds of nuclear sites, old and new'. This overview covers case studies for nuclear sites including some that had experienced major accidents. It derives that the earlier acknowledgement on the 'conceptual gap' appears no longer valid or at the very least, that the gap (if any) is extremely small. The RP of the environment is part of the on-going revision of the current IAEA Basic Safety Standards (BSS). We emphasize that the recently published BSS draft 1.0 in July 2008 covers (with adequacy) RP of the environment through general provisions (free of provisions to non-human species) on the assessment of environmental impact. (author)
Numerical simulation of a bubble rising in an environment consisting of Xanthan gum
Aguirre, Víctor A.; Castillo, Byron A.; Narvaez, Christian P.
2017-09-01
An improved numerical algorithm for front tracking method is developed to simulate a bubble rising in viscous liquid. In the new numerical algorithm, volume correction is introduced to conserve the bubble volume while tracking the bubble's rising and deforming. Volume flux conservation is adopted to solve the Navier-Stokes equation for fluid flow using finite volume method. Non-Newtonian fluids are widely used in industry such as feed and energy industries. In this research we used Xanthan gum which is a microbiological polysaccharide. In order to obtain the properties of the Xanthan gum, such as viscosity, storage and loss modulus, shear rate, etc., it was necessary to do an amplitude sweep and steady flow test in a rheometer with a concentric cylinder as geometry. Based on the data given and using a numerical regression, the coefficients required by Giesekus model are obtained. With these coefficients, it is possible to simulate the comportment of the fluid by the use of the developed algorithm. Once the data given by OpenFOAM is acquired, it is compared with the experimental data.
van der Vegt, H.; Storms, J.E.A.; Walstra, D.J.R.
2014-01-01
The assessment and production of hydrocarbon resources incorporates geological models created from core and wireline well data, as well as seismic data. This data is spatially discrete but is used create a spatially continuous model. However, the heterogeneity within depositional environments is on
Yassin, Mohamed F
2013-06-01
Due to heavy traffic emissions within an urban environment, air quality during the last decade becomes worse year by year and hazard to public health. In the present work, numerical modeling of flow and dispersion of gaseous emissions from vehicle exhaust in a street canyon were investigated under changes of the aspect ratio and wind direction. The three-dimensional flow and dispersion of gaseous pollutants were modeled using a computational fluid dynamics (CFD) model which was numerically solved using Reynolds-averaged Navier-Stokes (RANS) equations. The diffusion flow field in the atmospheric boundary layer within the street canyon was studied for different aspect ratios (W/H=1/2, 3/4, and 1) and wind directions (θ=90°, 112.5°, 135°, and 157.5°). The numerical models were validated against wind tunnel results to optimize the turbulence model. The numerical results agreed well with the wind tunnel results. The simulation demonstrated that the minimum concentration at the human respiration height within the street canyon was on the windward side for aspect ratios W/H=1/2 and 1 and wind directions θ=112.5°, 135°, and 157.5°. The pollutant concentration level decreases as the wind direction and aspect ratio increase. The wind velocity and turbulence intensity increase as the aspect ratio and wind direction increase.
Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan
2015-10-01
The impact of haze-fog on surface temperature, flow pattern, pollutant dispersion and pedestrian thermal comfort are investigated using computational fluid dynamics (CFD) approach based on a three-dimensional street canyon model under different haze-fog conditions. In this study, light extinction coefficient (Kex) is adopted to represent haze-fog pollution level. Numerical simulations are performed for different Kex values at four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST). The numerical results suggest that the surface temperature is strongly affected by the haze-fog condition. Surface heating induced by the solar radiation is enhanced by haze-fog, as higher surface temperature is observed under thicker haze-fog condition. Moreover, the temperature difference between sunlit and shadow surfaces is reduced, while that for the two shadow surfaces is slightly increased. Therefore, the surface temperature among street canyon facets becomes more evenly distributed under heavy haze-fog conditions. In addition, flow patterns are considerably altered by different haze-fog conditions, especially for the afternoon (1600 LST) case, in which thermal-driven flow has opposite direction as that of the wind-driven flow direction. Consequently, pollutants such as vehicular emissions will accumulate at pedestrian level, and pedestrian thermal comfort may lower under thicker haze-fog condition.
Numerical analysis of thermal environment control in high density data center
Energy Technology Data Exchange (ETDEWEB)
Kwon, Oh Kyung; Kim, Hyeon Joong; Cha, Dong An [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of)
2012-08-15
Increasing heat generation in CPUs can hamper effective recirculation and by pass because of the large temperature difference between the exhaust and the intake air through a server room. This increases the overall temperature inside a data center and decreases the efficiency of the data center's cooling system. The purpose of the data center's cooling system is to separate the intake and exhaust air by controlling the computer room air conditioner(CRAC). In this study, ICEPAK is used to conduct a numerical analysis of a data center's cooling system. The temperature distribution and the entire room are analyzed for different volumetric flow rates. The optimized volumetric flow rate is found for each CPU power. The heat removal and temperature distribution for CPU powers of 100, 120, and 140W are found to be the best for a volumetric flow rate of 0.15m'3'/s. The numerical analysis is verified through RTI indicators, and the results appear to be the most reliable when the RTI value is 81.
Jahantigh, Nabi; Keshavarz, Ali; Mirzaei, Masoud
2015-01-01
The aim of this study is to determine optimum hybrid heating systems parameters, such as temperature, surface area of a radiant heater and vent area to have thermal comfort conditions. DOE, Factorial design method is used to determine the optimum values for input parameters. A 3D model of a virtual standing thermal manikin with real dimensions is considered in this study. Continuity, momentum, energy, species equations for turbulent flow and physiological equation for thermal comfort are numerically solved to study heat, moisture and flow field. K - ɛRNG Model is used for turbulence modeling and DO method is used for radiation effects. Numerical results have a good agreement with the experimental data reported in the literature. The effect of various combinations of inlet parameters on thermal comfort is considered. According to Pareto graph, some of these combinations that have significant effect on the thermal comfort require no more energy can be used as useful tools. A better symmetrical velocity distribution around the manikin is also presented in the hybrid system.
Development of a high-fidelity numerical model for hazard prediction in the urban environment
International Nuclear Information System (INIS)
Lien, F.S.; Yee, E.; Ji, H.; Keats, A.; Hsieh, K.J.
2005-01-01
The release of chemical, biological, radiological, or nuclear (CBRN) agents by terrorists or rogue states in a North American city (densely populated urban centre) and the subsequent exposure, deposition, and contamination are emerging threats in an uncertain world. The transport, dispersion, deposition, and fate of a CBRN agent released in an urban environment is an extremely complex problem that encompasses potentially multiple space and time scales. The availability of high-fidelity, time-dependent models for the prediction of a CBRN agent's movement and fate in a complex urban environment can provide the strongest technical and scientific foundation for support of Canada's more broadly based effort at advancing counter-terrorism planning and operational capabilities. The objective of this paper is to report the progress of developing and validating an integrated, state-of-the-art, high-fidelity multi-scale, multi-physics modeling system for the accurate and efficient prediction of urban flow and dispersion of CBRN materials. Development of this proposed multi-scale modeling system will provide the real-time modeling and simulation tool required to predict injuries, casualties, and contamination and to make relevant decisions (based on the strongest technical and scientific foundations) in order to minimize the consequences of a CBRN incident based on a pre-determined decision making framework. (author)
Energy Technology Data Exchange (ETDEWEB)
Ersland, B.G.
1996-05-01
This mathematical doctoral thesis contains the theory, algorithms and numerical simulations for a heterogeneous oil reservoir. It presents the equations, which apply to immiscible and incompressible two-phase fluid flow in the reservoir, including the effect of capillary pressure forces, and emphasises in particular the interior boundary conditions at the interface between two sediments. Two different approaches are discussed. The first approach is to decompose the computational domain along the interior boundary and iterate between the subdomains until mass balance is achieved. The second approach accounts for the interior boundary conditions in the basis in which the solution is expanded, the basis being discontinuous over the interior boundaries. An overview of the construction of iterative solvers for partial differential equations by means of Schwartz methods is given, and the algorithm for local refinement with Schwartz iterations as iterative solver is described. The theory is then applied to a core plug problem in one and two space dimensions and the results of different methods compared. A general description is given of the computer simulation model, which is implemented in C++. 64 refs., 49 figs., 7 tabs.
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 Simulation of the Effects of Water Surface in Building Environment
Li, Guangyao; Pan, Yuqing; Yang, Li
2018-03-01
Water body could affect the thermal environment and airflow field in the building districts, because of its special thermal characteristics, evaporation and flat surface. The thermal influence of water body in Tongji University Jiading Campus front area was evaluated. First, a suitable evaporation model was selected and then was applied to calculate the boundary conditions of the water surface in the Fluent software. Next, the computational fluid dynamics (CFD) simulations were conducted on the models both with and without water, following the CFD practices guidelines. Finally, the outputs of the two simulations were compared with each other. Results showed that the effect of evaporative cooling from water surface strongly depends on the wind direction and temperature decrease was about 2∼5°C. The relative humidity within the enclosing area was affected by both the building arrangement and surrounding water. An increase of about 0.1∼0.2m/s of wind speed induced by the water evaporation was observed in the open space.
Energy Technology Data Exchange (ETDEWEB)
Gross, Guenter [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie
2012-08-15
A three-dimensional micro-scale model is used to study the effects of various greenery on temperature in a built-up environment. Green design elements like roofs and facades, lawns in courtyards and single trees are studied individually as well as in various combinations. Measures for comparison are temperatures at 2 m height and mean temperatures for the urban atmosphere up to the building height. Different types of greenery can reduce local temperatures up to 15 K during specific daytime hours. However, this extraordinary effect is restricted to a short time and especially to the direct surroundings, while an impact over larger distances is small. Roof and facade greenery have hardly any influence on temperature at the 2 m level but reduce daytime heating of the urban atmosphere to a minor degree, while the relevance of trees is more or less limited to the shadow effect. A significant decrease in urban temperatures can be achieved only with a large number of very different individual green elements. The largest effect on the urban atmosphere was simulated for a change in albedo resulting in a temperature decrease of some degrees around noon. (orig.)
International Nuclear Information System (INIS)
Pruess, Karsten
2003-01-01
The critical point of CO 2 is at temperature and pressure conditions of T crit = 31.04 C, P crit = 73.82 bar. At lower (subcritical) temperatures and/or pressures, CO 2 can exist in two different phase states, a liquid and a gaseous state, as well as in two-phase mixtures of these states. Disposal of CO 2 into brine formations would be made at supercritical pressures. However, CO 2 escaping from the storage reservoir may migrate upwards towards regions with lower temperatures and pressures, where CO 2 would be in subcritical conditions. An assessment of the fate of leaking CO 2 requires a capability to model not only supercritical but also subcritical CO 2 , as well as phase changes between liquid and gaseous CO 2 in sub-critical conditions. We have developed a methodology for numerically simulating the behavior of water-CO 2 mixtures in permeable media under conditions that may include liquid, gaseous, and supercritical CO 2 . This has been applied to simulations of leakage from a deep storage reservoir in which a rising CO 2 plume undergoes transitions from supercritical to subcritical conditions. We find strong cooling effects when liquid CO 2 rises to elevations where it begins to boil and evolve a gaseous CO 2 phase. A three-phase zone forms (aqueous - liquid - gas), which over time becomes several hundred meters thick as decreasing temperatures permit liquid CO 2 to advance to shallower elevations. Fluid mobilities are reduced in the three-phase region from phase interference effects. This impedes CO 2 upflow, causes the plume to spread out laterally, and gives rise to dispersed CO 2 discharge at the land surface. Our simulation suggests that temperatures along a CO 2 leakage path may decline to levels low enough so that solid water ice and CO 2 hydrate phases may be formed
A Review of Numerical Modelling of Multi-Scale Wind Turbines and Their Environment
Directory of Open Access Journals (Sweden)
Katrina Calautit
2018-03-01
Full Text Available Global demand for energy continues to increase rapidly, due to economic and population growth, especially for increasing market economies. These lead to challenges and worries about energy security that can increase as more users need more energy resources. Also, higher consumption of fossil fuels leads to more greenhouse gas emissions, which contribute to global warming. Moreover, there are still more people without access to electricity. Several studies have reported that one of the rapidly developing source of power is wind energy and with declining costs due to technology and manufacturing advancements and concerns over energy security and environmental issues, the trend is predicted to continue. As a result, tools and methods to simulate and optimize wind energy technologies must also continue to advance. This paper reviews the most recently published works in Computational Fluid Dynamic (CFD simulations of micro to small wind turbines, building integrated with wind turbines, and wind turbines installed in wind farms. In addition, the existing limitations and complications included with the wind energy system modelling were examined and issues that needs further work are highlighted. This study investigated the current development of CFD modelling of wind energy systems. Studies on aerodynamic interaction among the atmospheric boundary layer or wind farm terrain and the turbine rotor and their wakes were investigated. Furthermore, CFD combined with other tools such as blade element momentum were examined.
Energy Technology Data Exchange (ETDEWEB)
Baczewski, Andrew David; Shulenburger, Luke; Desjarlais, Michael Paul; Magyar, Rudolph J.
2014-02-01
In recent years, DFT-MD has been shown to be a useful computational tool for exploring the properties of WDM. These calculations achieve excellent agreement with shock compression experiments, which probe the thermodynamic parameters of the Hugoniot state. New X-ray Thomson Scattering diagnostics promise to deliver independent measurements of electronic density and temperature, as well as structural information in shocked systems. However, they require the development of new levels of theory for computing the associated observables within a DFT framework. The experimentally observable x-ray scattering cross section is related to the electronic density-density response function, which is obtainable using TDDFT - a formally exact extension of conventional DFT that describes electron dynamics and excited states. In order to develop a capability for modeling XRTS data and, more generally, to establish a predictive capability for rst principles simulations of matter in extreme conditions, real-time TDDFT with Ehrenfest dynamics has been implemented in an existing PAW code for DFT-MD calculations. The purpose of this report is to record implementation details and benchmarks as the project advances from software development to delivering novel scienti c results. Results range from tests that establish the accuracy, e ciency, and scalability of our implementation, to calculations that are veri ed against accepted results in the literature. Aside from the primary XRTS goal, we identify other more general areas where this new capability will be useful, including stopping power calculations and electron-ion equilibration.
International Nuclear Information System (INIS)
Nakano, Y.; Cho, T.
1985-01-01
It is clear that ground conditions have a large effect on the thermal environment. Plant canopies have their own characteristic types of architecture and have a great influence upon the action and reaction processes occurring between plants and their environment through the modification and interception of fluxes of radiation, heat and mass. A numerical experiment was carried out to determine the diurnal changes occurring in soil and air temperatures near the ground surface covered by a plant. The model assumed that a canopy can be mathematically condensed into a single plane and treated as a single ‘big leaf’. The stomatal resistance was estimated by using the rectangular hyperbolic relationship between stomatal resistance and irradiance. Wind velocity, potential temperature and specific humidity values of 3.6m/s, 25°C and 0.0015 were applied respectively at the upper boundary (100 m), and a temperature of 25°C was specified for the lower boundary (-0.5m). All these conditions were kept constant throughout the simulation period. The analysis was performed on the basis of irradiant data obtained in Fukuoka City (latitude 33° 38'N) on 26 th July, 1978. The temperature profiles during daylight were characterized by curves with a maximum in the canopy layer. The temperature range on the soil surface was reduced owing to the effect of shading by the leaves. These phenomena make the formation of the thermal environment on a plant canopy extremely complex. In the case presented in this paper, the type of plant canopy investigated was similar to that of a soybean field with plants 1.00 m high, but the method could easily be adapted to simulate the thermal environment of a tall canopy, such as that in a forest. (author)
International Nuclear Information System (INIS)
Trinitis, C; Schulz, M
2006-01-01
In today's world, the use of parallel programming and architectures is essential for simulating practical problems in engineering and related disciplines. Remarkable progress in CPU architecture, system scalability, and interconnect technology continues to provide new opportunities, as well as new challenges for both system architects and software developers. These trends are paralleled by progress in parallel algorithms, simulation techniques, and software integration from multiple disciplines. ParSim brings together researchers from both application disciplines and computer science and aims at fostering closer cooperation between these fields. Since its successful introduction in 2002, ParSim has established itself as an integral part of the EuroPVM/MPI conference series. In contrast to traditional conferences, emphasis is put on the presentation of up-to-date results with a short turn-around time. This offers a unique opportunity to present new aspects in this dynamic field and discuss them with a wide, interdisciplinary audience. The EuroPVM/MPI conference series, as one of the prime events in parallel computation, serves as an ideal surrounding for ParSim. This combination enables the participants to present and discuss their work within the scope of both the session and the host conference. This year, eleven papers from authors in nine countries were submitted to ParSim, and we selected five of them. They cover a wide range of different application fields including gas flow simulations, thermo-mechanical processes in nuclear waste storage, and cosmological simulations. At the same time, the selected contributions also address the computer science side of their codes and discuss different parallelization strategies, programming models and languages, as well as the use nonblocking collective operations in MPI. We are confident that this provides an attractive program and that ParSim will be an informal setting for lively discussions and for fostering new
W.H. Oldenmenger (Wendy); P.J. de Raaf (Pleun); C. de Klerk (Cora); C.C.D. van der Rijt (Carin)
2013-01-01
textabstractContext: To improve the management of cancer-related symptoms, systematic screening is necessary, often performed by using 0-10 numeric rating scales. Cut points are used to determine if scores represent clinically relevant burden. Objectives: The aim of this systematic review was to
International Nuclear Information System (INIS)
Kacha, K.; Djeffal, F.; Ferhati, H.; Arar, D.; Meguellati, M.
2015-01-01
We present a new approach based on the multi-trench technique to improve the electrical performances, which are the fill factor and the electrical efficiency. The key idea behind this approach is to introduce a new multi-trench region in the intrinsic layer, in order to modulate the total resistance of the solar cell. Based on 2-D numerical investigation and optimization of amorphous SiGe double-junction (a-Si:H/a-SiGe:H) thin film solar cells, in the present paper numerical models of electrical and optical parameters are developed to explain the impact of the multi-trench technique on the improvement of the double-junction solar cell electrical behavior for high performance photovoltaic applications. In this context, electrical characteristics of the proposed design are analyzed and compared with conventional amorphous silicon double-junction thin-film solar cells. (paper)
International Nuclear Information System (INIS)
Brechignac, F.; Polikarpov, G.; Oughton, D.H.; Hunter, G.; Alexakhin, R.; Zhu, Y.G.; Hilton, J.; Strand, P.
2003-01-01
The International union of radioecology has been created in 1970 as an international scientific organisation to develop, inform and advise on every aspect in relation with radioactivity in environment. It advises to fill the gaps of knowledge in order to develop strong scientific bases on which found the environmental protection. Seven points of knowledge are to improve: the understanding of transfer, bio accumulating and metabolism of radionuclides in ecosystems (specially the non human food chains), understanding of low dose radiation effects on fauna, flora in chronic exposure on several generations, identification of criteria and targets of effects to allow comparisons in term of impact, effects coming from several pollutions, radioactive or non radioactive ones, extrapolation between the biological organisation levels, analysis of simultaneous effects for man and other living organisms, harmonization of a radiation protection system and a protection system against chemical toxicity, development of quantities and units allowing to qualify the noxious effects of radiations and chemical pollutants on living beings. (N.C.)
Directory of Open Access Journals (Sweden)
F. Saez de Adana
2009-01-01
Full Text Available This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD for the analysis of Ultra-Wideband (UWB mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.
International Nuclear Information System (INIS)
Creighton, J.R.
1975-01-01
Waveforms and population distributions have been calculated by a numerical model and compared with experiment for an electric-discharge-initiated, pulsed NF 3 + H 2 chemical laser. The model treats each vibrational-rotational state separately, allowing rotational relaxation between adjacent states as well as vibrational relaxation and lasing according to P-branch selection rules. Calculated waveforms agree with experiment and show several features not seen when rotational equilibrium is assumed: simultaneous lasing on many transitions, cascade behavior, spikes due to laser relaxation oscillations, non-Boltzmann rotational distributions, and ''hole burning'' in the population distributions. The calculations give insight into the physical phenomena governing the shape and duration of the waveforms. The effect of varying certain parameters, relaxation rates, temperature, pressure, and diluents, is studied. Best fit to experimental waveforms is obtained when the rotational relaxation rate and collisional line broadening rate are approximately equal at about 10 times the hard sphere collision rate. The IXION computer code, developed for these calculations, is described in detail. In addition, an analytic model is presented which accounts for major features of the total (all transitions) output waveform of the laser assuming rotational equilibrium, a steady state laser model, and constant temperature. A second computer code, MINOTAR, was developed as a general purpose chemical kinetics code. It verifies the analytic model and extends the results to adiabatic reactions where the temperature varies, and can yield waveforms using the assumptions of rotational equilibrium and a steady state laser. The MINOTAR code, being general, can also be used for chemical kinetics problems such as air pollution and combustion
Hardesty, Britta D.; Harari, Joseph; Isobe, Atsuhiko; Lebreton, Laurent; Maximenko, Nikolai; Potemra, Jim; van Sebille, Erik; Vethaak, A.Dick; Wilcox, Chris
2017-01-01
Numerical modeling is one of the key tools with which we can gain insight into the distribution of marine litter, especially micro-plastics. Over the past decade, a series of numerical simulations have been constructed that specifically target floating marine litter, based on ocean models of various
Energy Technology Data Exchange (ETDEWEB)
Gossman, Michael S., E-mail: MGossman@TSRCC.com [Regulation Directive Medical Physics, Russell, KY (United States); Wilkinson, Jeffrey D. [Medtronic, Inc., Mounds View, MN (United States); Mallick, Avishek [Department of Mathematics, Marshall University, Huntington, WV (United States)
2014-01-01
In a 2-part study, we first examined the results of 71 surveyed physicians who provided responses on how they address the management of patients who maintained either a pacemaker or a defibrillator during radiation treatment. Second, a case review study is presented involving 112 medical records reviewed at 18 institutions to determine whether there was a change in the radiation prescription for the treatment of the target cancer, the method of radiation delivery, or the method of radiation image acquisition. Statistics are provided to illustrate the level of administrative policy; the level of communication between radiation oncologists and heart specialists; American Joint Committee on Cancer (AJCC) staging and classification; National Comprehensive Cancer Network (NCCN) guidelines; tumor site; patient's sex; patient's age; device type; manufacturer; live monitoring; and the reported decisions for planning, delivery, and imaging. This survey revealed that 37% of patient treatments were considered for some sort of change in this regard, whereas 59% of patients were treated without regard to these alternatives when available. Only 3% of all patients were identified with an observable change in the functionality of the device or patient status in comparison with 96% of patients with normal behavior and operating devices. Documented changes in the patient's medical record included 1 device exhibiting failure at 0.3-Gy dose, 1 device exhibiting increased sensor rate during dose delivery, 1 patient having an irregular heartbeat leading to device reprogramming, and 1 patient complained of twinging in the chest wall that resulted in a respiratory arrest. Although policies and procedures should directly involve the qualified medical physicist for technical supervision, their sufficient involvement was typically not requested by most respondents. No treatment options were denied to any patient based on AJCC staging, classification, or NCCN practice standards.
Feier, Ioan I., Jr.
The effect of flame radiation on concurrent-flow flame spread over a thin solid sample of finite width in a low-speed wind tunnel is modeled using three-dimensional full Navier-Stokes equations and three-dimensional flame radiation transfer equations. The formulation includes the conservation of mass, momentum, energy, and species: fuel vapor, oxygen, carbon dioxide and water vapor. The SN discrete ordinates method is used to solve the radiation transfer equation with a mean absorption coefficient kappa = Ckappa p, where kappap is the Planck mean absorption coefficient of the gas mixture. The varying parameter C has a value between 0 and 1; C represents the strength of flame radiation. In addition, the solid fuel absorptivity alpha is varied to ascertain the effect of flame radiation heat feedback to the solid. The flow tunnel modeled has a dimension of 10x10x30 cm, the solid fuel has a width of 6-cm with two 1-cm inert strips as edges. Incoming forced flow velocity (5 cm/s) of 21% oxygen is assumed. For comparison with the three-dimensional results, corresponding two-dimensional computations are also performed. Detailed spatial flame profiles, solid surface profiles, and heat fluxes are presented. Increasing the flame radiation strength decreases the flame length. Although flame radiation provides an additional heat transfer mechanism to preheat the solid, it is insufficient to offset the decreased convective heating due to the shorter flame; the net effect is a slower spread rate. The percentage of unreacted fuel vapor that escapes from the flame is under 2%. It is theorized that some of the pyrolyzed fuel vapor diffuses sideway and reacts at the flame edges. A radiative energy balance is analyzed also. Flame radiative feedback to the solid plays a more important role in two-dimensional flames. With high solid fuel absorptivity, a peak in the flame spread rate occurs at an intermediate value of flame radiation strength---due to the competition between two
Energy Technology Data Exchange (ETDEWEB)
Lepechinsky, D; Parlange, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1964-07-01
Dispersion curves including the effect of collisions have been calculated with a 7090 IBM computer for several types of laboratory hydrogen plasmas; Te = Ti = 1 eV; Te = 1 eV, Ti = 0,1 eV; Te = 10 eV, Ti = 2 eV; Te = 50 eV, Ti 10 eV, with neutral gas pressures of 10{sup -1}, 10{sup -3} and 10{sup -4} mmHg and electron densities of 10{sup 10}, 10{sup 13} and eventually 10{sup 15} el/cc. The corresponding collision frequencies with neutrals and between electrons and ions have been derived using appropriate relationships The dispersion equations used correspond to the macroscopic treatment. The real and imaginary parts of the wave number K are presented as a function of real values of the frequency {omega}, for electrostatic and electromagnetic waves and for e.m. waves propagating parallel to a permanent magnetic field of 500 gauss and 12.5 Kgauss. (authors) [French] Des courbes de dispersion tenant compte de l'effet des collisions ont ete calculees a l'aide d'un ordinateur IBM 7090 pour differents types de plasmas d'hydrogene se presentant au laboratoire; les temperatures electroniques et ioniques envisagees ont ete les suivantes: Te = Ti = 1 Ev; Te = 1 eV, Ti 0,1 eV; Te = 10 eV, Ti = 2 eV; Te = 50 eV, Ti = 10 eV; les pressions de neutres - de 10{sup -1}, 10{sup -3} et 10{sup -4} mmHg; les densites electroniques - de 10{sup 10}, 10{sup 13} et eventuellement de 10{sup 15} el/cc. Les frequences de collision avec les neutres et entre electrons et ions ont ete evaluees en fonction de ces donnees. Les equations, de dispersion utilisees correspondant au traitement macroscopique. On presente les valeurs des parties reelle et imaginaire du nombre d'ondes K en fonction de valeurs reelles de la frequence {omega} pour les ondes electrostatiques et electromagnetiques et pour les ondes e.m. se propageant parallelement a un champ magnetique permanent de 500 gauss et de 12,5 kgauss. (auteurs)
Energy Technology Data Exchange (ETDEWEB)
Zhang, Hong; Li, Huan; Chen, Jiabao; Zhao, Bo; Hu, Guangzhou [China Univ. of Mining and Technology, Jiangsu (China). School of Chemical Engineering
2013-07-01
Oxy-fuel technology could be successfully used to retrofit existing coal-fired power plants or alternatively be used to design and build new coal-fired power plants with almost zero emissions. Char reactivity under oxy-fuel conditions will have a significant impact on the coal burnout. In this paper, two fractions, representing organic-rich particles and organic particles with included minerals, were separated from each of three Chinese coals of different rank. They were then devolatilized at 1,450 C in a drop tube furnace (DTF) under N{sub 2} and CO{sub 2} environment, respectively. The chars were subjected to nitrogen adsorption study, thermogravimetric analysis and XRD analysis. It was found that char reactivity of all three pairs of chars were increased under CO{sub 2} environment as compared with that under N{sub 2} environment, but with differing trend. For the organic-rich samples the reactivity difference is increased with decreasing rank. On the contrary, for the samples of organic particles with included minerals, the reactivity difference is decreased with decreasing rank. Mechanism analysis showed that they are resulted not from gasification, but from a combination of changes in surface area and in the orderness of carbon structure in the chars, both of which, in turn, are resulted from the higher heat capacity of CO{sub 2} and the interaction between metastable liquid phase and the included minerals.
DEFF Research Database (Denmark)
Valentini, Chiara
2017-01-01
The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....
Ji, Xiaoxu; Eger, Tammy R; Dickey, James P
2017-03-01
Seats and cushions can attenuate whole-body vibration (WBV) exposures and minimize health risks for heavy machine operators. We successfully developed neural network (NN) algorithms to identify the vibration attenuation properties for four different seating conditions (seat/cushion combinations), and implemented each of the NN models to predict the equivalent daily exposure A(8) values for various vehicles in the forestry and mining environments. We also evaluated the performance of the new prototype No-Jolt™ air-inflated cushion and the original cushion of each seat with jolt exposures. We observed that the air cushion significantly improved the vibration attenuation properties of the seat that initially had good performance, but not for the seat that had relatively poor vibration attenuation properties. In addition, operator's anthropometrics and sex influenced the performance of the air-inflated cushion when the vibration environment included jolt exposures. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
Scott, L Ridgway
2011-01-01
Computational science is fundamentally changing how technological questions are addressed. The design of aircraft, automobiles, and even racing sailboats is now done by computational simulation. The mathematical foundation of this new approach is numerical analysis, which studies algorithms for computing expressions defined with real numbers. Emphasizing the theory behind the computation, this book provides a rigorous and self-contained introduction to numerical analysis and presents the advanced mathematics that underpin industrial software, including complete details that are missing from most textbooks. Using an inquiry-based learning approach, Numerical Analysis is written in a narrative style, provides historical background, and includes many of the proofs and technical details in exercises. Students will be able to go beyond an elementary understanding of numerical simulation and develop deep insights into the foundations of the subject. They will no longer have to accept the mathematical gaps that ex...
Directory of Open Access Journals (Sweden)
S. Baragetti
2014-10-01
Full Text Available In the present article, a review of the complete characterization in different aggressive media of a Ti-6Al-4V titanium alloy, performed by the Structural Mechanics Laboratory of the University of Bergamo, is presented. The light alloy has been investigated in terms of corrosion fatigue, by axial fatigue testing (R = 0.1 of smooth and notched flat dogbone specimens in laboratory air, 3.5% wt. NaCl–water mixture and methanol–water mixture at different concentrations. The first corrosive medium reproduced a marine environment, while the latter was used as a reference aggressive environment. Results showed that a certain corrosion fatigue resistance is found in a salt water medium, while the methanol environment caused a significant drop – from 23% to 55% in terms of limiting stress reduction – of the fatigue resistance of the Ti-6Al-4V alloy, even for a solution containing 5% of methanol. A Stress Corrosion Cracking (SCC experimental campaign at different methanol concentrations has been conducted over slightly notched dog-bone specimens (Kt = 1.18, to characterize the corrosion resistance of the alloy under quasi-static load conditions. Finally, crack propagation models have been implemented to predict the crack propagation rates for smooth specimens, by using Paris, Walker and Kato-Deng-Inoue-Takatsu propagation formulae. The different outcomes from the forecasting numerical models were compared with experimental results, proposing modeling procedures for the numerical simulation of fatigue behavior of a Ti-6Al-4V alloy.
Goh, Sien Fong
An experimental and numerical study of a turbulent smoke point diffusion flame in a quiescent and cross-flow condition was performed. The fuel mass flow rate of a turbulent smoke point flame was determined at a quiescent condition and in cross-flow with velocity ranging from 2 to 4 m/s. This fuel mass flow rate is defined as the Critical Fuel Mass Flow Rate (CFMFR). At a fuel mass flow rate below the CFMFR the flame produces smoke. In the dilution study, an amount of inert gas (nitrogen) was added to the fuel stream to achieve the smoke point condition for ten different fractions of CFMFR. From this dilution study, three regions were defined, the chemically-dominated region, transition region, and momentum-dominated region. The first objective of this study was to determine the factors behind the distinction of these three regions. The second objective was to understand the effect of cross-flow velocity on the smoke point flame structure. The flame temperature, radiation, geometrical dimension of flame, velocity, and global emissions and in-flame species concentration were measured. The third objective was to study a numerical model that can simulate the turbulent smoke point flame structure. The dilution study showed that the flames in quiescent condition and in the 3.5 and 4 m/s cross-flow condition had the chemically-dominated region at 5% to 20% CFMFR, the transition region at 20% to 40% CFMFR, and the momentum-dominated region at 40% to 100% CFMFR. On the other hand, the flame in cross-flow of 2 to 3 m/s showed the chemically-dominated region at 5% to 10% CFMFR, the transition region at 10% to 30% CFMFR, and the momentum-dominated region at 30% to 100% CFMFR. The chemically-dominated flame had a sharp dual-peak structure for the flame temperature, CO2 and NO concentration profiles at 25% and 50% flame length. However, the momentum-dominated region flame exhibited a dual peak structure only at 25% flame length. The decrease of flow rate from 30% to 10% CFMFR
Directory of Open Access Journals (Sweden)
Koichi Isawa
2015-09-01
Full Text Available To obtain a basic understanding of the resultant changes in the human body exergy balance (input, consumption, storage, and output accompanying outdoor air temperature fluctuations, a “human body system and a built environmental system” coupled with numerical analysis was conducted. The built environmental system assumed a wooden room equipped with passive cooling strategies, such as thermal insulation and solar shading devices. It was found that in the daytime, the cool radiation exergy emitted by surrounding surfaces, such as walls increased the rate of human body exergy consumption, whereas the warm radiant exergy emitted by the surrounding surfaces at night decreased the rate of human body exergy consumption. The results suggested that the rates and proportions of the different components in the exergy balance equation (exergy input, consumption, storage, and output vary according to the outdoor temperature and humidity conditions.
International Nuclear Information System (INIS)
Busa, J.; Ajryan, Eh.A.; Jurcisinova, E.; Jurcisin, M.; Remecky, R.
2009-01-01
Using the field-theoretic renormalization group, the influence of strong uniaxial small-scale anisotropy on the stability of inertial-range scaling regimes in a model of passive transverse vector field advected by an incompressible turbulent flow is investigated. The velocity field is taken to have a Gaussian statistics with zero mean and defined noise with finite time correlations. It is shown that the inertial-range scaling regimes are given by the existence of infrared stable fixed points of the corresponding renormalization group equations with some angle integrals. The analysis of integrals is given. The problem is solved numerically and the borderline spatial dimension d e (1,3] below which the stability of the scaling regime is not present is found as a function of anisotropy parameters
International Nuclear Information System (INIS)
McIntyre, A.D.; Turnbull, R.G.H.
1992-01-01
The development of the hydrocarbon resources of the North Sea has resulted in both offshore and onshore environmental repercussions, involving the existing physical attributes of the sea and seabed, the coastline and adjoining land. The social and economic repercussions of the industry were equally widespread. The dramatic and speedy impact of the exploration and exploitation of the northern North Sea resources in the early 1970s, on the physical resources of Scotland was quickly realised together with the concern that any environmental and social damage to the physical and social fabric should be kept to a minimum. To this end, a wide range of research and other activities by central and local government, and other interested agencies was undertaken to extend existing knowledge on the marine and terrestrial environments that might be affected by the oil and gas industry. The outcome of these activities is summarized in this paper. The topics covered include a survey of the marine ecosystems of the North Sea, the fishing industry, the impact of oil pollution on seabirds and fish stocks, the ecology of the Scottish coastline and the impact of the petroleum industry on a selection of particular sites. (author)
Chang, Jy-Tai; Wetzel, Peter J.
1991-01-01
To examine the effects of spatial variations of soil moisture and vegetation coverage on the evolution of a prestorm environment, the Goddard mesoscale model is modified to incorporate a simple evapotranspiration model that requires these two parameters. The case study of 3-4 June 1980 is of special interest due to the development of a tornado producing convective complex near Grand Island, Nebraska during a period of comparatively weak synoptic-scale forcing. It is shown that the observed stationary front was strongly enhanced by differential heating created by observed gradients of soil moisture, as acted upon by the vegetation cover.
Energy Technology Data Exchange (ETDEWEB)
Granet, S.
2000-01-28
Oil recovery from fractured reservoirs plays a very important role in the petroleum industry. Some of the world most productive oil fields are located in naturally fractured reservoirs. Modelling flow in such a fracture network is a very complex problem. This is conventionally done using a specific idealized model. This model is based on the Warren and Root representation and on a dual porosity, dual permeability approach. A simplified formulation of matrix-fracture fluid transfers uses a pseudo-steady-state transfer equation involving a constant exchange coefficient. Such a choice is one of the main difficulties of this approach. To get a better understanding of the simplifications involved in the dual porosity approach a reference model must be available. To obtain such a fine description, we have developed a new methodology. This technique called 'the fissure element methodology' is based on a specific gridding of the fractured medium. The fissure network is gridded with linear elements coupled with an unstructured triangular grid of matrix. An appropriate finite volume scheme has been developed to provide a good description of the flow. The numerical development of is precisely described. A simulator has been developed using this method. Several simulations have been realised. Comparisons have been done with different dual-porosity dual-permeability models. A reflexion concerning the choice of the exchange coefficient used in the dual porosity model is then proposed. This new tool has permit to have a better understanding of the production mechanisms of a complex fractured reservoir. (author)
Sun, Caiyun; Xu, Liang; Sun, Dazhi; Chen, Libo; Zou, Jiying; Zhang, Zhenxing
2017-08-29
This case study investigated the distribution and fate of organic pollutants in aquatic environments based on laboratory experiments and modeling. Pyrene (Pyr) is a hydrocarbon pollutant with adverse effects on aquatic ecosystems and human health, and was thus selected for this case study. The movement of Pyr was primarily influenced by its sorption from water onto sediment, and its desorption from sediment into water. Its elimination was mainly via biodegradation by microorganisms in sediment and by volatilization from water into air. The transport and elimination rates for Pyr were considerably influenced by temperature and moisture. Results of modeling with Markov chains revealed that the elimination of Pyr from water/sediment systems was the most rapid under wet conditions. Under average conditions, a Pyr concentration of 100 μg/L of in water in such a system declined to a negligible level over 250 h. Under wet conditions, this decrease occurred over 120 h. Finally, under dry conditions, it took 550 h to achieve the same degree of elimination.
Zhan, X.
2005-01-01
A parallel Fortran-MPI (Message Passing Interface) software for numerical inversion of the Laplace transform based on a Fourier series method is developed to meet the need of solving intensive computational problems involving oscillatory water level's response to hydraulic tests in a groundwater environment. The software is a parallel version of ACM (The Association for Computing Machinery) Transactions on Mathematical Software (TOMS) Algorithm 796. Running 38 test examples indicated that implementation of MPI techniques with distributed memory architecture speedups the processing and improves the efficiency. Applications to oscillatory water levels in a well during aquifer tests are presented to illustrate how this package can be applied to solve complicated environmental problems involved in differential and integral equations. The package is free and is easy to use for people with little or no previous experience in using MPI but who wish to get off to a quick start in parallel computing. ?? 2004 Elsevier Ltd. All rights reserved.
Teng, Weili; Li, Wen; Zhang, Qi; Wu, Depeng; Zhao, Xue; Li, Haiyan; Han, Yingpeng; Li, Wenbin
2017-08-01
The objective here was to identify QTL underlying soybean protein content (PC), and to evaluate the additive and epistatic effects of the QTLs. A mapping population, consisting of 129 recombinant inbred lines (RILs), was created by crossing 'Dongnong 46' and 'L-100'. Phenotypic data of the parents and RILs were collected for 4 years in three locations of Heilongjiang Province of China. A total of 213 SSR markers were used to construct a genetic linkage map. Eight QTLs, located on seven chromosomes (Chr), were identified to be associated with PC among the 10 tested environments. Of the seven QTLs, five QTLs, qPR-2 (Satt710, on Chr9), qPR-3 (Sat_122, on Chr12), qPR-5 (Satt543, on Chr17), qPR-7 (Satt163, on Chr18), and qPR-8 (Satt614, on Chr20), were detected in six, seven, seven, six, and seven environments, respectively, implying relatively stable QTLs. qPR-3 could explain 3.33%-11.26% of the phenotypic variation across eight tested environments. qPR-5 and qPR-8 explained 3.64%-10.1% and 11.86%-18.40% of the phenotypic variation, respectively, across seven tested environments. Eight QTLs associated with PC exhibited additive and (or) additive × environment interaction effects. The results showed that environment-independent QTLs often had higher additive effects. Moreover, five epistatic pairwise QTLs were identified in the 10 environments.
International Nuclear Information System (INIS)
Ahmed, Ahmed Qasim; Gao, Shian; Kareem, Ali Khaleel
2016-01-01
Highlights: • An advanced CFD program was developed and validated successfully. • The relation between the exhaust positions and heat sources was analysed. • Energy saving, thermal comfort and inhaled air quality were studied for 5 cases. • By combining the exhaust with office lamps, a 25% of energy saving was achieved. - Abstract: In an office room, many factors affect the pattern of airflow, thermal comfort, indoor air quality and energy saving. In this study, the effects of the location of exhaust diffusers where the warm and contaminant air is extracted and their relation to room heat sources on thermal comfort and energy saving were investigated numerically for an office served by a displacement ventilation system. The indoor air quality in the breathing level and the inhaled zone were also evaluated. The contaminants were released from window and door frames in order to simulate the contaminants coming from outside. The amount of energy consumption and the indoor thermal environment for various exhaust locations were investigated numerically using the computational fluid dynamics techniques. The results showed that the thermal indoor environment, thermal comfort, quality of indoor air and energy saving were greatly improved by combining the exhaust outlets with some of the room’s heat sources such as ceiling lamps and external walls. In particular, a 25.0% of energy saving was achieved by combining the exhaust diffuser with room’s ceiling lamps. In addition, locating the exhaust diffuser near the heat sources also reduced the cooling coil load by 13.8%. The risk of a large difference in temperature between the head and foot levels, increased particle concentration in the occupied zone, as well as increased energy consumption was also clearly demonstrated when the exhaust and recirculated air outlet (return opening) were combined in one unit in the occupied boundary area that is located at 2 m away from the occupants. Thus, for the optimum energy
International Nuclear Information System (INIS)
Anon.
1991-01-01
IGT's efforts in environmental protection are primarily concerned with reducing the level of undesirable emissions from combustion, treating solid and liquid waste materials, and producing cleaner fuels. Projects being funded include: an ultra-low-emission gas-fired cyclonic burner for firetube boiler retrofit; a combination of IGT's de-NOX technology for municipal solid waste combustors with the injection of sorbents to reduce pollutants; second-generation NOx reduction techniques for regenerative glass melting furnaces; investigation of the applicability of electric DC field flame stabilization; development of a slagging cyclonic combustor for a class of industrial solid wastes; remediation research of various biological, chemical, and thermal technologies for cleaning and/or immobilizing contaminants in soils and sludges; and fuel cell research on molten carbonate and solid oxide fuel cells
Gandois, L.; Agnan, Y.; Leblond, S.; Séjalon-Delmas, N.; Le Roux, G.; Probst, A.
2014-10-01
In order to assess the influence of local environment and spatial integration of Trace Metals (TM) by biomonitors, Al, As, Cd, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Sb, Sn, V and Zn and some rare earth element (REE) concentrations have been measured in lichens and mosses collected in three French forest sites located in three distinct mountainous areas, as well as in the local soil and bedrock, and in both bulk deposition (BD) and throughfall (TF). Similar enrichment factors (EF) were calculated using lichens and mosses and local bedrock for most elements, except for Cs, Mn, Ni, Pb, and Cu which were significantly (KW, p leaching (Mn), direct uptake (Ni), or dry deposition dissolution (Pb, Cu, Cs).
Are Humans too Numerous to Become Extinct?
Cairns, John
2009-01-01
Some claim that humans are too numerous to become extinct. However, passenger pigeon, once the most numerous birds on the planet, are now extinct. For years, humankind has been damaging its habitat, discharging toxic chemicals into the environment, and having harmful effects on agricultural productivity due to climate change. Humankind s extinction depends on the continuation of various human activities including economic growth, addiction to fossil fuel, over consumption, overpopulation, oc...
International Nuclear Information System (INIS)
Piran, T.
1982-01-01
There are many recent developments in numerical relativity, but there remain important unsolved theoretical and practical problems. The author reviews existing numerical approaches to solution of the exact Einstein equations. A framework for classification and comparison of different numerical schemes is presented. Recent numerical codes are compared using this framework. The discussion focuses on new developments and on currently open questions, excluding a review of numerical techniques. (Auth.)
Jacques, Ian
1987-01-01
This book is primarily intended for undergraduates in mathematics, the physical sciences and engineering. It introduces students to most of the techniques forming the core component of courses in numerical analysis. The text is divided into eight chapters which are largely self-contained. However, with a subject as intricately woven as mathematics, there is inevitably some interdependence between them. The level of difficulty varies and, although emphasis is firmly placed on the methods themselves rather than their analysis, we have not hesitated to include theoretical material when we consider it to be sufficiently interesting. However, it should be possible to omit those parts that do seem daunting while still being able to follow the worked examples and to tackle the exercises accompanying each section. Familiarity with the basic results of analysis and linear algebra is assumed since these are normally taught in first courses on mathematical methods. For reference purposes a list of theorems used in the t...
Digital Repository Service at National Institute of Oceanography (India)
Gaonkar, C.A.; Samiksha S.V.; George, G.; Aboobacker V.M.; Vethamony, P.; Anil, A.C.
Observations were carried out to monitor the larval abundance, settlement and recruitment of barnacles on a regular basis for a period of two years. The results were then compared with the numerical modelling studies carried out along the west coast...
Khabaza, I M
1960-01-01
Numerical Analysis is an elementary introduction to numerical analysis, its applications, limitations, and pitfalls. Methods suitable for digital computers are emphasized, but some desk computations are also described. Topics covered range from the use of digital computers in numerical work to errors in computations using desk machines, finite difference methods, and numerical solution of ordinary differential equations. This book is comprised of eight chapters and begins with an overview of the importance of digital computers in numerical analysis, followed by a discussion on errors in comput
Shibata, Masaru
2016-01-01
This book is composed of two parts: First part describes basics in numerical relativity, that is, the formulations and methods for a solution of Einstein's equation and general relativistic matter field equations. This part will be helpful for beginners of numerical relativity who would like to understand the content of numerical relativity and its background. The second part focuses on the application of numerical relativity. A wide variety of scientific numerical results are introduced focusing in particular on the merger of binary neutron stars and black holes.
International Nuclear Information System (INIS)
Koski, Jorman A.; Suo-Antitla, Ahti; Kramer M, Alex; Greiner, Miles
2000-01-01
Recent observations show that the thermal boundary conditions within large-scale fires are significantly affected by the presence of thermally massive objects. These objects cool the soot and gas near their surfaces, and these effects reduce the incoming radiant heat-flux to values lower than the levels expected from simple σT fire 4 models. They also affect the flow and temperature fields in the fire far from their surfaces. The Cask Analysis Fire Environment (CAFE) code has been developed at Sandia National Laboratories to provide an enhanced fire boundary condition for the design of radioactive material packages. CAFE is a set of computer subroutines that use computational fluid mechanics methods to predict convective heat transfer and mixing. It also includes models for fuel and oxygen transport, chemical reaction, and participating-media radiation heat transfer. This code uses two-dimensional computational models so that it has reasonably short turnaround times on standard workstations and is well suited for design and risk studies. In this paper, CAFE is coupled with a commercial finite-element program to model a large cylindrical calorimeter fully engulfed in a pool fire. The time-dependent heat-flux to the calorimeter and the calorimeter surface temperature are determined for several locations around the calorimeter circumference. The variation of heat-flux with location is determined for calorimeters with different diameters and wall thickness, and the observed effects discussed
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…
Bright, William
In most languages encountered by linguists, the numerals, considered as a paradigmatic set, constitute a morpho-syntactic problem of only moderate complexity. The Indo-Aryan language family of North India, however, presents a curious contrast. The relatively regular numeral system of Sanskrit, as it has developed historically into the modern…
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)
Meng, Xiaojing; Wang, Yi; Liu, Tiening; Xing, Xiao; Cao, Yingxue; Zhao, Jiangping
2016-01-01
Highlights: • The effects of radiation on predictive accuracy in numerical simulations were studied. • A scaled experimental model with a high-temperature heat source was set up. • Simulation results were discussed considering with and without radiation model. • The buoyancy force and the ventilation rate were investigated. - Abstract: This paper investigates the effects of radiation on predictive accuracy in the numerical simulations of industrial buildings. A scaled experimental model with a high-temperature heat source is set up and the buoyancy-driven natural ventilation performance is presented. Besides predicting ventilation performance in an industrial building, the scaled model in this paper is also used to generate data to validate the numerical simulations. The simulation results show good agreement with the experiment data. The effects of radiation on predictive accuracy in the numerical simulations are studied for both pure convection model and combined convection and radiation model. Detailed results are discussed regarding the temperature and velocity distribution, the buoyancy force and the ventilation rate. The temperature and velocity distributions through the middle plane are presented for the pure convection model and the combined convection and radiation model. It is observed that the overall temperature and velocity magnitude predicted by the simulations for pure convection were significantly greater than those for the combined convection and radiation model. In addition, the Grashof number and the ventilation rate are investigated. The results show that the Grashof number and the ventilation rate are greater for the pure convection model than for the combined convection and radiation model.
Kaplan, Michael L.; Huffman, Allan W.; Lux, Kevin M.; Cetola, Jeffrey D.; Charney, Joseph J.; Riordan, Allen J.; Lin, Yuh-Lang; Waight, Kenneth T., III; Proctor, Fred (Technical Monitor)
2003-01-01
Simulation experiments reveal key processes that organize a hydrostatic environment conducive to severe turbulence. The paradigm requires juxtaposition of the entrance region of a curved jet stream, which is highly subgeostrophic, with the entrance region of a straight jet stream, which is highly supergeostrophic. The wind and mass fields become misphased as the entrance regions converge resulting in the significant spatial variation of inertial forcing, centripetal forcing, and along- and cross-stream pressure gradient forcing over a mesobeta scale region. This results in frontogenesis and the along-stream divergence of cyclonic and convergence of cyclonic ageostrophic vertical vorticity. The centripetally forced mesoscale front becomes the locus of large gradients of ageostrophic vertical vorticity along an overturning isentrope. This region becomes favorable for streamwise vorticity gradient formation enhancing the environment for organization of horizontal vortex tubes in the presence of buoyant forcing.
2016-03-01
around a libration point in the Earth -Moon system are used as unpredictable transfer pathways when traveling from one Earth orbit to another...spacecraft traveling from one Earth orbit to another in a multi- body environment, as well as characterizing the potential motions in the vicinity of...an inspiring account of how using the gravity of the Moon assisted in placing the satellite in a favorable Earth orbit after a rocket malfunction left
Introduction to numerical analysis
Hildebrand, F B
1987-01-01
Well-known, respected introduction, updated to integrate concepts and procedures associated with computers. Computation, approximation, interpolation, numerical differentiation and integration, smoothing of data, other topics in lucid presentation. Includes 150 additional problems in this edition. Bibliography.
Brezinski, C
2012-01-01
Numerical analysis has witnessed many significant developments in the 20th century. This book brings together 16 papers dealing with historical developments, survey papers and papers on recent trends in selected areas of numerical analysis, such as: approximation and interpolation, solution of linear systems and eigenvalue problems, iterative methods, quadrature rules, solution of ordinary-, partial- and integral equations. The papers are reprinted from the 7-volume project of the Journal of Computational and Applied Mathematics on '/homepage/sac/cam/na2000/index.html<
Baker, John G.
2009-01-01
Recent advances in numerical relativity have fueled an explosion of progress in understanding the predictions of Einstein's theory of gravity, General Relativity, for the strong field dynamics, the gravitational radiation wave forms, and consequently the state of the remnant produced from the merger of compact binary objects. I will review recent results from the field, focusing on mergers of two black holes.
International Nuclear Information System (INIS)
Gazave, J.
2007-12-01
When fusion ignition will be attained inside the target chambers of high energy laser facilities (LMJ-France and NIF-Usa), a harsh environment, composed of nuclear particles and an electromagnetic pulse (EMP) will be induced. All electronic devices located in the vicinity will be sensitive to this environment. In the first part of this work, a simulation method has been developed to evaluate transient currents that will be induced in coaxial cables. The relevance of this model is then discussed thanks to comparisons with experimental results. In a second part, the possibility to simulate the propagation of the EMP, inside and outside such a big structure as a target chamber, using the finite difference in time and domain (FDTD) method is evaluated. The use of a classic FDTD method is impossible for this kind of simulation because of the huge computer resources needed. It is the reason why a 3-dimensional space-time sub-grid method for FDTD has been developed and some massively parallel FDTD calculations have also been performed. (author)
Manobianco, John; Uccellini, Louis W.; Brill, Keith F.; Kuo, Ying-Hwa
1992-01-01
A mesoscale numerical model is combined with a dynamic data assimilation via Newtonian relaxation, or 'nudging', to provide initial conditions for subsequent simulations of the QE II cyclone. Both the nudging technique and the inclusion of supplementary data are shown to have a large positive impact on the simulation of the QE II cyclone during the initial phase of rapid cyclone development. Within the initial development period (from 1200 to 1800 UTC 9 September 1978), the dynamic assimilation of operational and bogus data yields a coherent two-layer divergence pattern that is not well defined in the model run using only the operational data and static initialization. Diagnostic analysis based on the simulations show that the initial development of the QE II storm between 0000 UTC 9 September and 0000 UTC 10 September was embedded within an indirect circulation of an intense 300-hPa jet streak, was related to baroclinic processes extending throughout a deep portion of the troposphere, and was associated with a classic two-layer mass-divergence profile expected for an extratropical cyclone.
International Nuclear Information System (INIS)
Tanguy, Dome
2001-01-01
After a presentation of the industrial context and of some knowledge about stress corrosion cracking (SCC) of 5xxx alloys (notably their sensitivity to intergranular dissolution in presence of the Al 3 Mg 2 phase in grain boundaries) and about other mechanisms intervening in SCC, this research thesis reports a characterization of intergranular precipitation in the alloys for which SCC and corrosion fatigue tests have been performed. Experimental results are reported and discussed (crack initiation and growth, growth rate, loading mode). The simulation of a model microstructure at the atomic scale is presented. It allows hydrogen trapping to be studied with respect to the presence of magnesium at the grain boundary. A numerical model of the Al-Mg system is developed to study the first stages of magnesium-rich intergranular precipitation. The next part reports the study of hydrogen intergranular trapping in Al-Mg by focusing on the Mg-H binding energy and on trapping occurring in the boundary. In conclusion, the author proposes a fracture mechanism at the atomic scale
Nakamura, T
1993-01-01
In GR13 we heard many reports on recent. progress as well as future plans of detection of gravitational waves. According to these reports (see the report of the workshop on the detection of gravitational waves by Paik in this volume), it is highly probable that the sensitivity of detectors such as laser interferometers and ultra low temperature resonant bars will reach the level of h ~ 10—21 by 1998. in this level we may expect the detection of the gravitational waves from astrophysical sources such as coalescing binary neutron stars once a year or so. Therefore the progress in numerical relativity is urgently required to predict the wave pattern and amplitude of the gravitational waves from realistic astrophysical sources. The time left for numerical relativists is only six years or so although there are so many difﬁculties in principle as well as in practice.
Singh, Devraj
2015-01-01
Numerical Problems in Physics, Volume 1 is intended to serve the need of the students pursuing graduate and post graduate courses in universities with Physics and Materials Science as subject including those appearing in engineering, medical, and civil services entrance examinations. KEY FEATURES: * 29 chapters on Optics, Wave & Oscillations, Electromagnetic Field Theory, Solid State Physics & Modern Physics * 540 solved numerical problems of various universities and ompetitive examinations * 523 multiple choice questions for quick and clear understanding of subject matter * 567 unsolved numerical problems for grasping concepts of the various topic in Physics * 49 Figures for understanding problems and concept
Numerical computations with GPUs
Kindratenko, Volodymyr
2014-01-01
This book brings together research on numerical methods adapted for Graphics Processing Units (GPUs). It explains recent efforts to adapt classic numerical methods, including solution of linear equations and FFT, for massively parallel GPU architectures. This volume consolidates recent research and adaptations, covering widely used methods that are at the core of many scientific and engineering computations. Each chapter is written by authors working on a specific group of methods; these leading experts provide mathematical background, parallel algorithms and implementation details leading to
Energy Technology Data Exchange (ETDEWEB)
Yu, Ye, E-mail: yyu@lzb.ac.cn [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); He, Jianjun, E-mail: 18766167147@163.com [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China); Zhao, Suping [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Na [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Weather Modification Office, Qinghai Meteorological Bureau, Xining 810001 (China); Chen, Jinbei [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Mao, Hongjun; Wu, Lin [College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China)
2016-11-01
Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in
International Nuclear Information System (INIS)
Yu, Ye; He, Jianjun; Zhao, Suping; Liu, Na; Chen, Jinbei; Mao, Hongjun; Wu, Lin
2016-01-01
Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in
Dahlquist, Germund
1974-01-01
""Substantial, detailed and rigorous . . . readers for whom the book is intended are admirably served."" - MathSciNet (Mathematical Reviews on the Web), American Mathematical Society.Practical text strikes fine balance between students' requirements for theoretical treatment and needs of practitioners, with best methods for large- and small-scale computing. Prerequisites are minimal (calculus, linear algebra, and preferably some acquaintance with computer programming). Text includes many worked examples, problems, and an extensive bibliography.
Neoclassical transport including collisional nonlinearity.
Candy, J; Belli, E A
2011-06-10
In the standard δf theory of neoclassical transport, the zeroth-order (Maxwellian) solution is obtained analytically via the solution of a nonlinear equation. The first-order correction δf is subsequently computed as the solution of a linear, inhomogeneous equation that includes the linearized Fokker-Planck collision operator. This equation admits analytic solutions only in extreme asymptotic limits (banana, plateau, Pfirsch-Schlüter), and so must be solved numerically for realistic plasma parameters. Recently, numerical codes have appeared which attempt to compute the total distribution f more accurately than in the standard ordering by retaining some nonlinear terms related to finite-orbit width, while simultaneously reusing some form of the linearized collision operator. In this work we show that higher-order corrections to the distribution function may be unphysical if collisional nonlinearities are ignored.
Handbook of numerical analysis
Ciarlet, Philippe G
Mathematical finance is a prolific scientific domain in which there exists a particular characteristic of developing both advanced theories and practical techniques simultaneously. Mathematical Modelling and Numerical Methods in Finance addresses the three most important aspects in the field: mathematical models, computational methods, and applications, and provides a solid overview of major new ideas and results in the three domains. Coverage of all aspects of quantitative finance including models, computational methods and applications Provides an overview of new ideas an
Introduction to precise numerical methods
Aberth, Oliver
2007-01-01
Precise numerical analysis may be defined as the study of computer methods for solving mathematical problems either exactly or to prescribed accuracy. This book explains how precise numerical analysis is constructed. The book also provides exercises which illustrate points from the text and references for the methods presented. All disc-based content for this title is now available on the Web. · Clearer, simpler descriptions and explanations ofthe various numerical methods· Two new types of numerical problems; accurately solving partial differential equations with the included software and computing line integrals in the complex plane.
International Nuclear Information System (INIS)
Petroll, M.
1986-01-01
Apart from the report of the Federal Ministry for the Environment, the publication contains the following chapters: 1) Monitoring of environmental radioactivity; 2) analysis of propagation processes; 3) control and measuring points of the Federal Laender to monitor environmental radioactivity; 4) determination of the local dose rate; 5) concentration of radioactivity in air and soil (graphs); 6) up-to-date knowledge of events, measures; 7) nuclear power plants in the Federal Republic of Germany (review of technical safety); 8) interim report of the Committee on Reactor Safety - Reaktorsicherheitskommission - for preliminary evaluation; 9) interim report of the Committee on Radiation Protection - Strahlenschutzkommission - for assessment and evaluation of the effects. (HP) [de
Confidence in Numerical Simulations
Energy Technology Data Exchange (ETDEWEB)
Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-02-23
This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to “forecast,” that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists “think.” This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. “Confidence” derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.
Confidence in Numerical Simulations
International Nuclear Information System (INIS)
Hemez, Francois M.
2015-01-01
This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to ''forecast,'' that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists ''think.'' This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. ''Confidence'' derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.
Numerical calculations in quantum field theories
International Nuclear Information System (INIS)
Rebbi, C.
1984-01-01
Four lecture notes are included: (1) motivation for numerical calculations in Quantum Field Theory; (2) numerical simulation methods; (3) Monte Carlo studies of Quantum Chromo Dynamics; and (4) systems with fermions. 23 references
Phthalates biodegradation in the environment.
Liang, Da-Wei; Zhang, Tong; Fang, Herbert H P; He, Jianzhong
2008-08-01
Phthalates are synthesized in massive amounts to produce various plastics and have become widespread in environments following their release as a result of extensive usage and production. This has been of an environmental concern because phthalates are hepatotoxic, teratogenic, and carcinogenic by nature. Numerous studies indicated that phthalates can be degraded by bacteria and fungi under aerobic, anoxic, and anaerobic conditions. This paper gives a review on the biodegradation of phthalates and includes the following aspects: (1) the relationship between the chemical structure of phthalates and their biodegradability, (2) the biodegradation of phthalates by pure/mixed cultures, (3) the biodegradation of phthalates under various environments, and (4) the biodegradation pathways of phthalates.
Energy Technology Data Exchange (ETDEWEB)
Iskra, A.A.; Burykin, A.A. [All-Russia Research Institute of Chemical Technology (Russian Federation); Lebedev, O.G.; Popov, V.K.; Churaev, R.S. [Russian Research Center Kurchatov Institute (Russian Federation)
2004-07-01
The goal of the 'Radinfo' project is creation of a meta-database (MDB) and radioecological cadastres, geo-referenced information systems being a basic component of those ones, and conducting (using those systems) evaluation study of possible pathways of radionuclides from the radiation-hazardous objects, radioactive waste, and contaminated areas, followed by the ranking of threats, for two priority regions of Russia selected on the basis of expert interrogation: the North-West of Russia and Krasnoyarsk region. In order to achieve the goal the following investigation tools are being created and/or applied for evaluation study on the two regions: - information data files (local databases, publications etc.) on radiation sources, radioactive waste, and contaminated areas, as well as on the environment characteristics in the studied regions; - radionuclide transfer pathways models; - sets of local geo-information systems (comprising a basic component of GIS cadastres), embracing (scanning) the areas of two regions of interest and allowing to assess the dynamics of real and probable migration of radionuclides. The RadInfo MDB development is based on use of multi-level architecture of the Web-technologies. The multi-level architecture, unlike that of conventional 'Client-Server' type, provides more versatility and scalability. In this particular case a three-level version is realized. A SQL-server (MySQL) is used as a database server. The well-known Apache Web-server is used as an application server. For its part it provides execution of scripts in the PHP language (the scripts are program extension of the server part)With such kind of configuration there is no need in using special software on the client side. Any browser (for instance, Microsoft Internet Explorer or Netscape Navigator) can be used as a workplace. The configuration is very simple as far as as its installation, adjustment and use are concerned. The meta-database and the models of
International Nuclear Information System (INIS)
Iskra, A.A.; Burykin, A.A.; Lebedev, O.G.; Popov, V.K.; Churaev, R.S.
2004-01-01
The goal of the 'Radinfo' project is creation of a meta-database (MDB) and radioecological cadastres, geo-referenced information systems being a basic component of those ones, and conducting (using those systems) evaluation study of possible pathways of radionuclides from the radiation-hazardous objects, radioactive waste, and contaminated areas, followed by the ranking of threats, for two priority regions of Russia selected on the basis of expert interrogation: the North-West of Russia and Krasnoyarsk region. In order to achieve the goal the following investigation tools are being created and/or applied for evaluation study on the two regions: - information data files (local databases, publications etc.) on radiation sources, radioactive waste, and contaminated areas, as well as on the environment characteristics in the studied regions; - radionuclide transfer pathways models; - sets of local geo-information systems (comprising a basic component of GIS cadastres), embracing (scanning) the areas of two regions of interest and allowing to assess the dynamics of real and probable migration of radionuclides. The RadInfo MDB development is based on use of multi-level architecture of the Web-technologies. The multi-level architecture, unlike that of conventional 'Client-Server' type, provides more versatility and scalability. In this particular case a three-level version is realized. A SQL-server (MySQL) is used as a database server. The well-known Apache Web-server is used as an application server. For its part it provides execution of scripts in the PHP language (the scripts are program extension of the server part)With such kind of configuration there is no need in using special software on the client side. Any browser (for instance, Microsoft Internet Explorer or Netscape Navigator) can be used as a workplace. The configuration is very simple as far as as its installation, adjustment and use are concerned. The meta-database and the models of radionuclide transfer
Matlab programming for numerical analysis
Lopez, Cesar
2014-01-01
MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. Programming MATLAB for Numerical Analysis introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. You will first become
Family environment and child development
Directory of Open Access Journals (Sweden)
Tina Kavčič
2005-04-01
Full Text Available The paper presents an overview of research findings on influence of family environment, especially parental behaviour, on child's development. Contemporary authors question early socialization researchers' claims that family characteristics and parental behaviour have important influence on behaviour of their children. Later researchers examined the size and durability of possible effects of family environment on child development. In addition, they focused on establishing whether it is actually the parental behaviour that influences child's development or, on the contrary, parental behaviour represents mainly a reaction to child's characteristics. Behaviour genetic studies have provided evidence that many traditional measures of family environment, including measures of parental behaviour, show genetic influence, thus reflecting genetically influenced child characteristics. Behaviour geneticists also suggest that environmental influences on child (personality development include predominantly non-shared environment, i.e. individual child's specific experiences, his/her own perceptions and interpretations of objectively same events. Based on empirically determined significant genetic effects on most behavioural traits and inconclusive results of studies on effects of family environment on child development some authors believe that it is not the parents, but rather genetic factor and/or peers who have the key role in child development. With respect to findings of behaviour genetics numerous recent studies of relations between family environment and child development involve child specific measures of (extrafamilial environment and examine the interactions between characteristics of an individual and those of his/her environment.
Numerical differential protection
Ziegler, Gerhard
2012-01-01
Differential protection is a fast and selective method of protection against short-circuits. It is applied in many variants for electrical machines, trans?formers, busbars, and electric lines.Initially this book covers the theory and fundamentals of analog and numerical differential protection. Current transformers are treated in detail including transient behaviour, impact on protection performance, and practical dimensioning. An extended chapter is dedicated to signal transmission for line protection, in particular, modern digital communication and GPS timing.The emphasis is then pla
Numerical Optimization in Microfluidics
DEFF Research Database (Denmark)
Jensen, Kristian Ejlebjærg
2017-01-01
Numerical modelling can illuminate the working mechanism and limitations of microfluidic devices. Such insights are useful in their own right, but one can take advantage of numerical modelling in a systematic way using numerical optimization. In this chapter we will discuss when and how numerical...... optimization is best used....
Methods of numerical relativity
International Nuclear Information System (INIS)
Piran, T.
1983-01-01
Numerical Relativity is an alternative to analytical methods for obtaining solutions for Einstein equations. Numerical methods are particularly useful for studying generation of gravitational radiation by potential strong sources. The author reviews the analytical background, the numerical analysis aspects and techniques and some of the difficulties involved in numerical relativity. (Auth.)
Henderson, Michael
1997-08-01
The Numerical Analysis Objects project (NAO) is a project in the Mathematics Department of IBM's TJ Watson Research Center. While there are plenty of numerical tools available today, it is not an easy task to combine them into a custom application. NAO is directed at the dual problems of building applications from a set of tools, and creating those tools. There are several "reuse" projects, which focus on the problems of identifying and cataloging tools. NAO is directed at the specific context of scientific computing. Because the type of tools is restricted, problems such as tools with incompatible data structures for input and output, and dissimilar interfaces to tools which solve similar problems can be addressed. The approach we've taken is to define interfaces to those objects used in numerical analysis, such as geometries, functions and operators, and to start collecting (and building) a set of tools which use these interfaces. We have written a class library (a set of abstract classes and implementations) in C++ which demonstrates the approach. Besides the classes, the class library includes "stub" routines which allow the library to be used from C or Fortran, and an interface to a Visual Programming Language. The library has been used to build a simulator for petroleum reservoirs, using a set of tools for discretizing nonlinear differential equations that we have written, and includes "wrapped" versions of packages from the Netlib repository. Documentation can be found on the Web at "http://www.research.ibm.com/nao". I will describe the objects and their interfaces, and give examples ranging from mesh generation to solving differential equations.
Numerical calculations near spatial infinity
International Nuclear Information System (INIS)
Zenginoglu, Anil
2007-01-01
After describing in short some problems and methods regarding the smoothness of null infinity for isolated systems, I present numerical calculations in which both spatial and null infinity can be studied. The reduced conformal field equations based on the conformal Gauss gauge allow us in spherical symmetry to calculate numerically the entire Schwarzschild-Kruskal spacetime in a smooth way including spacelike, null and timelike infinity and the domain close to the singularity
Numerical modelling of mine workings.
CSIR Research Space (South Africa)
Lightfoot, N
1999-03-01
Full Text Available to cover most of what is required for a practising rock mechanics engineer to be able to use any of these five programs to solve practical mining problems. The chapters on specific programs discuss their individual strengths and weaknesses and highlight... and applications of numerical modelling in the context of the South African gold and platinum mining industries. This includes an example that utilises a number of different numerical 3 modelling programs to solve a single problem. This particular example...
New seismograph includes filters
Energy Technology Data Exchange (ETDEWEB)
1979-11-02
The new Nimbus ES-1210 multichannel signal enhancement seismograph from EG and G geometrics has recently been redesigned to include multimode signal fillers on each amplifier. The ES-1210F is a shallow exploration seismograph for near subsurface exploration such as in depth-to-bedrock, geological hazard location, mineral exploration, and landslide investigations.
Analytic device including nanostructures
Di Fabrizio, Enzo M.; Fratalocchi, Andrea; Totero Gongora, Juan Sebastian; Coluccio, Maria Laura; Candeloro, Patrizio; Cuda, Gianni
2015-01-01
A device for detecting an analyte in a sample comprising: an array including a plurality of pixels, each pixel including a nanochain comprising: a first nanostructure, a second nanostructure, and a third nanostructure, wherein size of the first nanostructure is larger than that of the second nanostructure, and size of the second nanostructure is larger than that of the third nanostructure, and wherein the first nanostructure, the second nanostructure, and the third nanostructure are positioned on a substrate such that when the nanochain is excited by an energy, an optical field between the second nanostructure and the third nanostructure is stronger than an optical field between the first nanostructure and the second nanostructure, wherein the array is configured to receive a sample; and a detector arranged to collect spectral data from a plurality of pixels of the array.
Saskatchewan resources. [including uranium
Energy Technology Data Exchange (ETDEWEB)
1979-09-01
The production of chemicals and minerals for the chemical industry in Saskatchewan are featured, with some discussion of resource taxation. The commodities mentioned include potash, fatty amines, uranium, heavy oil, sodium sulfate, chlorine, sodium hydroxide, sodium chlorate and bentonite. Following the successful outcome of the Cluff Lake inquiry, the uranium industry is booming. Some developments and production figures for Gulf Minerals, Amok, Cenex and Eldorado are mentioned.
DEFF Research Database (Denmark)
Korzenevica, Marina
2016-01-01
Following the civil war of 1996–2006, there was a dramatic increase in the labor mobility of young men and the inclusion of young women in formal education, which led to the transformation of the political landscape of rural Nepal. Mobility and schooling represent a level of prestige that rural...... politics. It analyzes how formal education and mobility either challenge or reinforce traditional gendered norms which dictate a lowly position for young married women in the household and their absence from community politics. The article concludes that women are simultaneously excluded and included from...... community politics. On the one hand, their mobility and decision-making powers decrease with the increase in the labor mobility of men and their newly gained education is politically devalued when compared to the informal education that men gain through mobility, but on the other hand, schooling strengthens...
Anthropogenic activities including pollution and contamination of coastal marine environment.
Digital Repository Service at National Institute of Oceanography (India)
Ansari, Z.A.; Matondkar, S.G.P.
stream_size 8 stream_content_type text/plain stream_name J_Ecophysiol_Occup_Health_14_71.pdf.txt stream_source_info J_Ecophysiol_Occup_Health_14_71.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...
Essential numerical computer methods
Johnson, Michael L
2010-01-01
The use of computers and computational methods has become ubiquitous in biological and biomedical research. During the last 2 decades most basic algorithms have not changed, but what has is the huge increase in computer speed and ease of use, along with the corresponding orders of magnitude decrease in cost. A general perception exists that the only applications of computers and computer methods in biological and biomedical research are either basic statistical analysis or the searching of DNA sequence data bases. While these are important applications they only scratch the surface of the current and potential applications of computers and computer methods in biomedical research. The various chapters within this volume include a wide variety of applications that extend far beyond this limited perception. As part of the Reliable Lab Solutions series, Essential Numerical Computer Methods brings together chapters from volumes 210, 240, 321, 383, 384, 454, and 467 of Methods in Enzymology. These chapters provide ...
Numerical Hydrodynamics in General Relativity
Directory of Open Access Journals (Sweden)
Font José A.
2003-01-01
Full Text Available The current status of numerical solutions for the equations of ideal general relativistic hydrodynamics is reviewed. With respect to an earlier version of the article, the present update provides additional information on numerical schemes, and extends the discussion of astrophysical simulations in general relativistic hydrodynamics. Different formulations of the equations are presented, with special mention of conservative and hyperbolic formulations well-adapted to advanced numerical methods. A large sample of available numerical schemes is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. A comprehensive summary of astrophysical simulations in strong gravitational fields is presented. These include gravitational collapse, accretion onto black holes, and hydrodynamical evolutions of neutron stars. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances on the formulation of the gravitational field and hydrodynamic equations and the numerical methodology designed to solve them.
Numerical Simulation of a Tornado Generating Supercell
Proctor, Fred H.; Ahmad, Nashat N.; LimonDuparcmeur, Fanny M.
2012-01-01
The development of tornadoes from a tornado generating supercell is investigated with a large eddy simulation weather model. Numerical simulations are initialized with a sounding representing the environment of a tornado producing supercell that affected North Carolina and Virginia during the Spring of 2011. The structure of the simulated storm was very similar to that of a classic supercell, and compared favorably to the storm that affected the vicinity of Raleigh, North Carolina. The presence of mid-level moisture was found to be important in determining whether a supercell would generate tornadoes. The simulations generated multiple tornadoes, including cyclonic-anticyclonic pairs. The structure and the evolution of these tornadoes are examined during their lifecycle.
Numerical methods in finance and economics a MATLAB-based introduction
Brandimarte, Paolo
2006-01-01
A state-of-the-art introduction to the powerful mathematical and statistical tools used in the field of financeThe use of mathematical models and numerical techniques is a practice employed by a growing number of applied mathematicians working on applications in finance. Reflecting this development, Numerical Methods in Finance and Economics: A MATLAB?-Based Introduction, Second Edition bridges the gap between financial theory and computational practice while showing readers how to utilize MATLAB?--the powerful numerical computing environment--for financial applications.The author provides an essential foundation in finance and numerical analysis in addition to background material for students from both engineering and economics perspectives. A wide range of topics is covered, including standard numerical analysis methods, Monte Carlo methods to simulate systems affected by significant uncertainty, and optimization methods to find an optimal set of decisions.Among this book''s most outstanding features is the...
Numerical investigations of gravitational collapse
Energy Technology Data Exchange (ETDEWEB)
Csizmadia, Peter; Racz, Istvan, E-mail: iracz@rmki.kfki.h [RMKI, Budapest, Konkoly Thege Miklos ut 29-33, H-1121 (Hungary)
2010-03-01
Some properties of a new framework for simulating generic 4-dimensional spherically symmetric gravitating systems are discussed. The framework can be used to investigate spacetimes that undergo complete gravitational collapse. The analytic setup is chosen to ensure that our numerical method is capable to follow the time evolution everywhere, including the black hole region.
Numerical methods using Matlab
Lindfield, George
2012-01-01
Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of useful and important numerical algorithms that can be implemented into MATLAB for a graphical interpretation to help researchers analyze a particular outcome. Many worked examples are given together with exercises and solutions to illustrate how numerical methods can be used to study problems that have applications in the biosciences, chaos, optimization, engineering and science across the board. Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of use
Numerical analysis of electromagnetic fields
Zhou Pei Bai
1993-01-01
Numerical methods for solving boundary value problems have developed rapidly. Knowledge of these methods is important both for engineers and scientists. There are many books published that deal with various approximate methods such as the finite element method, the boundary element method and so on. However, there is no textbook that includes all of these methods. This book is intended to fill this gap. The book is designed to be suitable for graduate students in engineering science, for senior undergraduate students as well as for scientists and engineers who are interested in electromagnetic fields. Objective Numerical calculation is the combination of mathematical methods and field theory. A great number of mathematical concepts, principles and techniques are discussed and many computational techniques are considered in dealing with practical problems. The purpose of this book is to provide students with a solid background in numerical analysis of the field problems. The book emphasizes the basic theories ...
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
Erickson, Mary; Delahunt, Michael
2010-01-01
Most art teachers would agree that architecture is an important form of visual art, but they do not always include it in their curriculums. In this article, the authors share core ideas from "Architecture and Environment," a teaching resource that they developed out of a long-term interest in teaching architecture and their fascination with the…
Energy Technology Data Exchange (ETDEWEB)
Godard, V
2005-01-15
The behaviour of concrete, considered as isotropic for a sound material, becomes anisotropic and unilateral as soon as microcracks are initiated. Concrete also shows a different behaviour in tension than in compression. However, isotropic models, which are more simple and time costless, are still widely used for industrial applications. An anisotropic and unilateral model, with few parameters, is thus proposed in the present work, which enhances the accuracy of the description of concrete's behaviour, while remaining suitable for industrial studies. The validation of the model is based on experimental results. Numerical simulations of structures are also proposed, among which one concerns a representative volume of a confinement vessel. Finally, a non local theory is investigated to overcome the problems induced by strain localisation. (author)
Theory and applications of numerical analysis
Phillips, G M
1996-01-01
This text is a self-contained Second Edition, providing an introductory account of the main topics in numerical analysis. The book emphasizes both the theorems which show the underlying rigorous mathematics andthe algorithms which define precisely how to program the numerical methods. Both theoretical and practical examples are included.* a unique blend of theory and applications* two brand new chapters on eigenvalues and splines* inclusion of formal algorithms* numerous fully worked examples* a large number of problems, many with solutions
Numerically and experimentally analysis of creep
International Nuclear Information System (INIS)
Fontanive, J.A.
1982-11-01
The problems of creep in concrete are analyzed experimentally and numerically, comparing with classical methods and suggesting a numerical procedure for the solution of these problems. Firstly, fundamentals of viscoelasticity and its application to concrete behaviour representation are presented. Then the theories of Dischinger and Arutyunyan are studied, and a computing numerical solutions are compared in several examples. Finally, experiences on creep and relaxation are described, and its result are analyzed. Some coments on possible future developments are included. (Author) [pt
Numerical Feedback Stabilization with Applications to Networks
Directory of Open Access Journals (Sweden)
Simone Göttlich
2017-01-01
Full Text Available The focus is on the numerical consideration of feedback boundary control problems for linear systems of conservation laws including source terms. We explain under which conditions the numerical discretization can be used to design feedback boundary values for network applications such as electric transmission lines or traffic flow systems. Several numerical examples illustrate the properties of the results for different types of networks.
Kavka, P.; Jeřábek, J.; Strouhal, L.
2016-12-01
The contribution presents a numerical model SMODERP that is used for calculation and prediction of surface runoff and soil erosion from agricultural land. The physically based model includes the processes of infiltration (Phillips equation), surface runoff routing (kinematic wave based equation), surface retention, surface roughness and vegetation impact on runoff. The model is being developed at the Department of Irrigation, Drainage and Landscape Engineering, Civil Engineering Faculty, CTU in Prague. 2D version of the model was introduced in last years. The script uses ArcGIS system tools for data preparation. The physical relations are implemented through Python scripts. The main computing part is stand alone in numpy arrays. Flow direction is calculated by Steepest Descent algorithm and in multiple flow algorithm. Sheet flow is described by modified kinematic wave equation. Parameters for five different soil textures were calibrated on the set of hundred measurements performed on the laboratory and filed rainfall simulators. Spatially distributed models enable to estimate not only surface runoff but also flow in the rills. Development of the rills is based on critical shear stress and critical velocity. For modelling of the rills a specific sub model was created. This sub model uses Manning formula for flow estimation. Flow in the ditches and streams are also computed. Numerical stability of the model is controled by Courant criterion. Spatial scale is fixed. Time step is dynamic and depends on the actual discharge. The model is used in the framework of the project "Variability of Short-term Precipitation and Runoff in Small Czech Drainage Basins and its Influence on Water Resources Management". Main goal of the project is to elaborate a methodology and online utility for deriving short-term design precipitation series, which could be utilized by a broad community of scientists, state administration as well as design planners. The methodology will account for
Ziegler, Gerhard
2011-01-01
Distance protection provides the basis for network protection in transmission systems and meshed distribution systems. This book covers the fundamentals of distance protection and the special features of numerical technology. The emphasis is placed on the application of numerical distance relays in distribution and transmission systems.This book is aimed at students and engineers who wish to familiarise themselves with the subject of power system protection, as well as the experienced user, entering the area of numerical distance protection. Furthermore it serves as a reference guide for s
Numerical methods for metamaterial design
2013-01-01
This book describes a relatively new approach for the design of electromagnetic metamaterials. Numerical optimization routines are combined with electromagnetic simulations to tailor the broadband optical properties of a metamaterial to have predetermined responses at predetermined wavelengths. After a review of both the major efforts within the field of metamaterials and the field of mathematical optimization, chapters covering both gradient-based and derivative-free design methods are considered. Selected topics including surrogate-base optimization, adaptive mesh search, and genetic algorithms are shown to be effective, gradient-free optimization strategies. Additionally, new techniques for representing dielectric distributions in two dimensions, including level sets, are demonstrated as effective methods for gradient-based optimization. Each chapter begins with a rigorous review of the optimization strategy used, and is followed by numerous examples that combine the strategy with either electromag...
Remarks on numerical semigroups
International Nuclear Information System (INIS)
Torres, F.
1995-12-01
We extend results on Weierstrass semigroups at ramified points of double covering of curves to any numerical semigroup whose genus is large enough. As an application we strengthen the properties concerning Weierstrass weights state in [To]. (author). 25 refs
Numerical semigroups and applications
Assi, Abdallah
2016-01-01
This work presents applications of numerical semigroups in Algebraic Geometry, Number Theory, and Coding Theory. Background on numerical semigroups is presented in the first two chapters, which introduce basic notation and fundamental concepts and irreducible numerical semigroups. The focus is in particular on free semigroups, which are irreducible; semigroups associated with planar curves are of this kind. The authors also introduce semigroups associated with irreducible meromorphic series, and show how these are used in order to present the properties of planar curves. Invariants of non-unique factorizations for numerical semigroups are also studied. These invariants are computationally accessible in this setting, and thus this monograph can be used as an introduction to Factorization Theory. Since factorizations and divisibility are strongly connected, the authors show some applications to AG Codes in the final section. The book will be of value for undergraduate students (especially those at a higher leve...
Mastorakis, Nikos E
2009-01-01
Features contributions that are focused on significant aspects of current numerical methods and computational mathematics. This book carries chapters that advanced methods and various variations on known techniques that can solve difficult scientific problems efficiently.
Introductory numerical analysis
Pettofrezzo, Anthony J
2006-01-01
Written for undergraduates who require a familiarity with the principles behind numerical analysis, this classical treatment encompasses finite differences, least squares theory, and harmonic analysis. Over 70 examples and 280 exercises. 1967 edition.
Numerical analysis of bifurcations
International Nuclear Information System (INIS)
Guckenheimer, J.
1996-01-01
This paper is a brief survey of numerical methods for computing bifurcations of generic families of dynamical systems. Emphasis is placed upon algorithms that reflect the structure of the underlying mathematical theory while retaining numerical efficiency. Significant improvements in the computational analysis of dynamical systems are to be expected from more reliance of geometric insight coming from dynamical systems theory. copyright 1996 American Institute of Physics
On numerical considerations for modeling reactive astrophysical shocks
International Nuclear Information System (INIS)
Papatheodore, Thomas L.; Messer, O. E. Bronson
2014-01-01
Simulating detonations in astrophysical environments is often complicated by numerical approximations to shock structure. A common prescription to ensure correct detonation speeds and associated quantities is to prohibit burning inside the numerically broadened shock. We have performed a series of simulations to verify the efficacy of this approximation and to understand how resolution and dimensionality might affect its use. Our results show that in one dimension, prohibiting burning in the shock is important wherever the carbon burning length is not resolved, in keeping with the results of Fryxell et al. In two dimensions, we find that the prohibition of shock burning effectively inhibits the development of cellular structure for all but the most highly resolved cases. We discuss the possible impacts this outcome may have on sub-grid models and detonation propagation in models of Type Ia supernovae, including potential impacts on observables.
Numerical Relativity Simulations for Black Hole Merger Astrophysics
Baker, John G.
2010-01-01
Massive black hole mergers are perhaps the most energetic astronomical events, establishing their importance as gravitational wave sources for LISA, and also possibly leading to observable influences on their local environments. Advances in numerical relativity over the last five years have fueled the development of a rich physical understanding of general relativity's predictions for these events. Z will overview the understanding of these event emerging from numerical simulation studies. These simulations elucidate the pre-merger dynamics of the black hole binaries, the consequent gravitational waveform signatures ' and the resulting state, including its kick velocity, for the final black hole produced by the merger. Scenarios are now being considered for observing each of these aspects of the merger, involving both gravitational-wave and electromagnetic astronomy.
Numerical simulation of mechatronic sensors and actuators
Kaltenbacher, Manfred
2007-01-01
Focuses on the physical modeling of mechatronic sensors and actuators and their precise numerical simulation using the Finite Element Method (FEM). This book discusses the physical modeling as well as numerical computation. It also gives a comprehensive introduction to finite elements, including their computer implementation.
Uncertainty Quantification in Numerical Aerodynamics
Litvinenko, Alexander; Matthies, Hermann G.; Liu, Dishi; Schillings, Claudia; Schulz, Volker
2017-01-01
In numerical section we compares five methods, including quasi-Monte Carlo quadrature, polynomial chaos with coefficients determined by sparse quadrature and gradient-enhanced version of Kriging, radial basis functions and point collocation polynomial chaos, in their efficiency in estimating statistics of aerodynamic performance upon random perturbation to the airfoil geometry [D.Liu et al '17]. For modeling we used the TAU code, developed in DLR, Germany.
Numerical and symbolic scientific computing
Langer, Ulrich
2011-01-01
The book presents the state of the art and results and also includes articles pointing to future developments. Most of the articles center around the theme of linear partial differential equations. Major aspects are fast solvers in elastoplasticity, symbolic analysis for boundary problems, symbolic treatment of operators, computer algebra, and finite element methods, a symbolic approach to finite difference schemes, cylindrical algebraic decomposition and local Fourier analysis, and white noise analysis for stochastic partial differential equations. Further numerical-symbolic topics range from
Numerical methods in software and analysis
Rice, John R
1992-01-01
Numerical Methods, Software, and Analysis, Second Edition introduces science and engineering students to the methods, tools, and ideas of numerical computation. Introductory courses in numerical methods face a fundamental problem-there is too little time to learn too much. This text solves that problem by using high-quality mathematical software. In fact, the objective of the text is to present scientific problem solving using standard mathematical software. This book discusses numerous programs and software packages focusing on the IMSL library (including the PROTRAN system) and ACM Algorithm
Powder agglomeration in a microgravity environment
Cawley, James D.
1994-01-01
This is the final report for NASA Grant NAG3-755 entitled 'Powder Agglomeration in a Microgravity Environment.' The research program included both two types of numerical models and two types of experiments. The numerical modeling included the use of Monte Carlo type simulations of agglomerate growth including hydrodynamic screening and molecular dynamics type simulations of the rearrangement of particles within an agglomerate under a gravitational field. Experiments included direct observation of the agglomeration of submicron alumina and indirect observation, using small angle light scattering, of the agglomeration of colloidal silica and aluminum monohydroxide. In the former class of experiments, the powders were constrained to move on a two-dimensional surface oriented to minimize the effect of gravity. In the latter, some experiments involved mixture of suspensions containing particles of opposite charge which resulted in agglomeration on a very short time scale relative to settling under gravity.
Characterizing stellar and exoplanetary environments
Khodachenko, Maxim
2015-01-01
In this book an international group of specialists discusses studies of exoplanets subjected to extreme stellar radiation and plasma conditions. It is shown that such studies will help us to understand how terrestrial planets and their atmospheres, including the early Venus, Earth and Mars, evolved during the host star’s active early phase. The book presents an analysis of findings from Hubble Space Telescope observations of transiting exoplanets, as well as applications of advanced numerical models for characterizing the upper atmosphere structure and stellar environments of exoplanets. The authors also address detections of atoms and molecules in the atmosphere of “hot Jupiters” by NASA’s Spitzer telescope. The observational and theoretical investigations and discoveries presented are both timely and important in the context of the next generation of space telescopes. The book is divided into four main parts, grouping chapters on exoplanet host star radiation and plasma environments, exoplanet u...
Numerical Modeling and Mechanical Analysis of Flexible Risers
Directory of Open Access Journals (Sweden)
J. Y. Li
2015-01-01
Full Text Available ABAQUS is used to create a detailed finite element model for a 10-layer unbonded flexible riser to simulate the riser’s mechanical behavior under three load conditions: tension force and internal and external pressure. It presents a technique to create detailed finite element model and to analyze flexible risers. In FEM model, all layers are modeled separately with contact interfaces; interaction between steel trips in certain layers has been considered as well. FEM model considering contact interaction, geometric nonlinearity, and friction has been employed to accurately simulate the structural behavior of riser. The model includes the main features of the riser geometry with very little simplifying assumptions. The model was solved using a fully explicit time-integration scheme implemented in a parallel environment on an eight-processor cluster and 24 G memory computer. There is a very good agreement obtained from numerical and analytical comparisons, which validates the use of numerical model here. The results from the numerical simulation show that the numerical model takes into account various details of the riser. It has been shown that the detailed finite element model can be used to predict riser’s mechanics behavior under various load cases and bound conditions.
JDiffraction: A GPGPU-accelerated JAVA library for numerical propagation of scalar wave fields
Piedrahita-Quintero, Pablo; Trujillo, Carlos; Garcia-Sucerquia, Jorge
2017-05-01
JDiffraction, a GPGPU-accelerated JAVA library for numerical propagation of scalar wave fields, is presented. Angular spectrum, Fresnel transform, and Fresnel-Bluestein transform are the numerical algorithms implemented in the methods and functions of the library to compute the scalar propagation of the complex wavefield. The functionality of the library is tested with the modeling of easy to forecast numerical experiments and also with the numerical reconstruction of a digitally recorded hologram. The performance of JDiffraction is contrasted with a library written for C++, showing great competitiveness in the apparently less complex environment of JAVA language. JDiffraction also includes JAVA easy-to-use methods and functions that take advantage of the computation power of the graphic processing units to accelerate the processing times of 2048×2048 pixel images up to 74 frames per second.
A deterministic combination of numerical and physical models for coastal waves
DEFF Research Database (Denmark)
Zhang, Haiwen
2006-01-01
of numerical and physical modelling hence provides an attractive alternative to the use of either tool on it's own. The goal of this project has been to develop a deterministically combined numerical/physical model where the physical wave tank is enclosed in a much larger computational domain, and the two......Numerical and physical modelling are the two main tools available for predicting the influence of water waves on coastlines and structures placed in the near-shore environment. Numerical models can cover large areas at the correct scale, but are limited in their ability to capture strong...... nonlinearities, wave breaking, splash, mixing, and other such complicated physics. Physical models naturally include the real physics (at the model scale), but are limited by the physical size of the facility and must contend with the fact that different physical effects scale differently. An integrated use...
Numerical 3-D Modelling of Overflows
DEFF Research Database (Denmark)
Larsen, Torben; Nielsen, L.; Jensen, B.
2008-01-01
-dimensional so-called Volume of Fluid Models (VOF-models) based on the full Navier-Stokes equations (named NS3 and developed by DHI Water & Environment) As a general conclusion, the two numerical models show excellent results when compared with measurements. However, considerable errors occur when...
Numerical methods in electron magnetic resonance
International Nuclear Information System (INIS)
Soernes, A.R.
1998-01-01
The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system
Numerical methods in electron magnetic resonance
Energy Technology Data Exchange (ETDEWEB)
Soernes, A.R
1998-07-01
The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system.
Extending flood damage assessment methodology to include ...
African Journals Online (AJOL)
Optimal and sustainable flood plain management, including flood control, can only be achieved when the impacts of flood control measures are considered for both the man-made and natural environments, and the sociological aspects are fully considered. Until now, methods/models developed to determine the influences ...
Institute of Scientific and Technical Information of China (English)
刘泽军; 张超; 武丽丽; 吴建军
2015-01-01
液滴碰撞现象普遍存在于动力装置燃烧室喷嘴的下游区域，影响燃料的雾化性能。为了揭示相同直径的双液滴中心碰撞机理，求解了轴对称坐标系下的 N-S 方程，采用 VOF(Volume of Fluid)方法捕捉液滴碰撞过程中气液自由表面的演化规律。利用 Qian 等提供的实验结果对计算模型进行数值校验，验证了模型的准确性。在此基础上，研究了环境压强对液滴碰撞反弹后不同结果(分离和融合)的影响，分析了环境压强和 Weber 数对液滴碰撞分离的影响。结果表明，液滴在碰撞反弹后的状态(分离或融合)是由液滴间气膜压强与环境气动阻力共同作用的结果，环境压强对液滴碰撞分离过程基本没有影响；Weber 数越大，碰撞过程中变形的幅度越大。%The phenomena of droplet collision not only exist widely in the downstream region of ejection nozzles in the combustion chambers of power equipments,but also they will affect the atomization characteristics of fuel.In order to reveal the binary collision mechanism of droplets with equal diameters, the Navier-Stokes equations are firstly solved in the axisymmetric coordinates and the method of VOF (Volume of Fluid)is utilized to track the evolution disciplines of the gas-liquid free surface during the process of droplet collision.Then,veracity of the numerical models is validated with the experimental results of Qian.Effects of ambient pressure on different results (separation and coalescence)after drop-let bouncing are investigated,and effects of ambient pressure and Weber number on separation of two droplets after collision are also analyzed.Results show that states (separation and coalescence)of drop-lets after collision and rebound are determined by the pressure of gaseous film between droplets and gas-eous dynamic resistance together.Moreover,the separation process of two droplets after collision is inde-pendent of the ambient pressure
DEFF Research Database (Denmark)
Henriquez, Vicente Cutanda
This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... manipulations are developed to satisfy the more complicated boundary conditions, and a model of a condenser microphone with a coupled membrane is developed. The model is tested against measurements of ¼ inch condenser microphones and analytical calculations. A detailed discussion of the results is given....
On numerical Bessel transformation
International Nuclear Information System (INIS)
Sommer, B.; Zabolitzky, J.G.
1979-01-01
The authors present a computer program to calculate the three dimensional Fourier or Bessel transforms and definite integrals with Bessel functions. Numerical integration of systems containing Bessel functions occurs in many physical problems, e.g. electromagnetic form factor of nuclei, all transitions involving multipole expansions at high momenta. Filon's integration rule is extended to spherical Bessel functions. The numerical error is of the order of the Simpson error term of the function which has to be transformed. Thus one gets a stable integral even at large arguments of the transformed function. (Auth.)
International Nuclear Information System (INIS)
McKee, S.; Elliott, C.M.
1986-01-01
The applications of mathematics to industrial problems involves the formulation of problems which are amenable to mathematical investigation, mathematical modelling, the solution of the mathematical problem and the inter-pretation of the results. There are 12 chapters describing industrial problems where mathematics and numerical analysis can be applied. These range from the numerical assessment of the flatness of engineering surfaces and plates, the design of chain links, control problems in tidal power generation and low thrust satellite trajectory optimization to mathematical models in welding. One chapter, on the ageing of stainless steels, is indexed separately. (UK)
Competition for vitamin B1 (thiamin) structures numerous ecological interactions.
Kraft, Clifford E; Angert, Esther R
2017-06-01
Thiamin (vitamin B1) is a cofactor required for essential biochemical reactions in all living organisms, yet free thiamin is scarce in the environment. The diversity of biochemical pathways involved in the acquisition, degradation, and synthesis of thiamin indicates that organisms have evolved numerous ecological strategies for meeting this nutritional requirement. In this review we synthesize information from multiple disciplines to show how the complex biochemistry of thiamin influences ecological outcomes of interactions between organisms in environments ranging from the open ocean and the Australian outback to the gastrointestinal tract of animals. We highlight population and ecosystem responses to the availability or absence of thiamin. These include widespread mortality of fishes, birds, and mammals, as well as the thiamin-dependent regulation of ocean productivity. Overall, we portray thiamin biochemistry as the foundation for molecularly mediated ecological interactions that influence survival and abundance of a vast array of organisms.
Probabilistic numerics and uncertainty in computations.
Hennig, Philipp; Osborne, Michael A; Girolami, Mark
2015-07-08
We deliver a call to arms for probabilistic numerical methods : algorithms for numerical tasks, including linear algebra, integration, optimization and solving differential equations, that return uncertainties in their calculations. Such uncertainties, arising from the loss of precision induced by numerical calculation with limited time or hardware, are important for much contemporary science and industry. Within applications such as climate science and astrophysics, the need to make decisions on the basis of computations with large and complex data have led to a renewed focus on the management of numerical uncertainty. We describe how several seminal classic numerical methods can be interpreted naturally as probabilistic inference. We then show that the probabilistic view suggests new algorithms that can flexibly be adapted to suit application specifics, while delivering improved empirical performance. We provide concrete illustrations of the benefits of probabilistic numeric algorithms on real scientific problems from astrometry and astronomical imaging, while highlighting open problems with these new algorithms. Finally, we describe how probabilistic numerical methods provide a coherent framework for identifying the uncertainty in calculations performed with a combination of numerical algorithms (e.g. both numerical optimizers and differential equation solvers), potentially allowing the diagnosis (and control) of error sources in computations.
Anastassiou, George A
2015-01-01
This is the first numerical analysis text to use Sage for the implementation of algorithms and can be used in a one-semester course for undergraduates in mathematics, math education, computer science/information technology, engineering, and physical sciences. The primary aim of this text is to simplify understanding of the theories and ideas from a numerical analysis/numerical methods course via a modern programming language like Sage. Aside from the presentation of fundamental theoretical notions of numerical analysis throughout the text, each chapter concludes with several exercises that are oriented to real-world application. Answers may be verified using Sage. The presented code, written in core components of Sage, are backward compatible, i.e., easily applicable to other software systems such as Mathematica®. Sage is open source software and uses Python-like syntax. Previous Python programming experience is not a requirement for the reader, though familiarity with any programming language is a p...
Numerical Estimation in Preschoolers
Berteletti, Ilaria; Lucangeli, Daniela; Piazza, Manuela; Dehaene, Stanislas; Zorzi, Marco
2010-01-01
Children's sense of numbers before formal education is thought to rely on an approximate number system based on logarithmically compressed analog magnitudes that increases in resolution throughout childhood. School-age children performing a numerical estimation task have been shown to increasingly rely on a formally appropriate, linear…
International Nuclear Information System (INIS)
Sollogoub, Pierre
2001-01-01
Numerical analyses are needed in different steps of the overall design process. Complex models or non-linear reactor core behaviour are important for qualification and/or comparison of results obtained. Adequate models and test should be defined. Fuel assembly, fuel row, and the complete core should be tested for seismic effects causing LOCA and flow-induced vibrations (FIV)
Development of numerical concepts
Directory of Open Access Journals (Sweden)
Sabine Peucker
2013-06-01
Full Text Available The development of numerical concepts is described from infancy to preschool age. Infants a few days old exhibit an early sensitivity for numerosities. In the course of development, nonverbal mental models allow for the exact representation of small quantities as well as changes in these quantities. Subitising, as the accurate recognition of small numerosities (without counting, plays an important role. It can be assumed that numerical concepts and procedures start with insights about small numerosities. Protoquantitative schemata comprise fundamental knowledge about quantities. One-to-one-correspondence connects elements and numbers, and, for this reason, both quantitative and numerical knowledge. If children understand that they can determine the numerosity of a collection of elements by enumerating the elements, they have acquired the concept of cardinality. Protoquantitative knowledge becomes quantitative if it can be applied to numerosities and sequential numbers. The concepts of cardinality and part-part-whole are key to numerical development. Developmentally appropriate learning and teaching should focus on cardinality and part-part-whole concepts.
Isaacson, Eugene
1994-01-01
This excellent text for advanced undergraduates and graduate students covers norms, numerical solution of linear systems and matrix factoring, iterative solutions of nonlinear equations, eigenvalues and eigenvectors, polynomial approximation, and other topics. It offers a careful analysis and stresses techniques for developing new methods, plus many examples and problems. 1966 edition.
Paradoxes in numerical calculations
Czech Academy of Sciences Publication Activity Database
Brandts, J.; Křížek, Michal; Zhang, Z.
2016-01-01
Roč. 26, č. 3 (2016), s. 317-330 ISSN 1210-0552 R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985840 Keywords : round-off errors * numerical instability * recurrence formulae Subject RIV: BA - General Mathematics Impact factor: 0.394, year: 2016
A numerical model for buoyant oil jets and smoke plumes
International Nuclear Information System (INIS)
Zheng, L.; Yapa, P. D.
1997-01-01
Development of a 3-D numerical model to simulate the behaviour of buoyant oil jets from underwater accidents and smoke plumes from oil burning was described. These jets/plumes can be oil-in-water, oil/gas mixture in water, gas in water, or gas in air. The ambient can have a 3-D flow structure, and spatially/temporally varying flow conditions. The model is based on the Lagrangian integral technique. The model formulation of oil jet includes the diffusion and dissolution of oil from the jet to the ambient environment. It is suitable to simulate well blowout accidents that can occur in deep waters, including that of the North Sea. The model has been thoroughly tested against a variety of data, including data from both laboratory and field experiments. In all cases the simulation data compared very well with experimental data. 26 refs., 10 figs
Constrained evolution in numerical relativity
Anderson, Matthew William
The strongest potential source of gravitational radiation for current and future detectors is the merger of binary black holes. Full numerical simulation of such mergers can provide realistic signal predictions and enhance the probability of detection. Numerical simulation of the Einstein equations, however, is fraught with difficulty. Stability even in static test cases of single black holes has proven elusive. Common to unstable simulations is the growth of constraint violations. This work examines the effect of controlling the growth of constraint violations by solving the constraints periodically during a simulation, an approach called constrained evolution. The effects of constrained evolution are contrasted with the results of unconstrained evolution, evolution where the constraints are not solved during the course of a simulation. Two different formulations of the Einstein equations are examined: the standard ADM formulation and the generalized Frittelli-Reula formulation. In most cases constrained evolution vastly improves the stability of a simulation at minimal computational cost when compared with unconstrained evolution. However, in the more demanding test cases examined, constrained evolution fails to produce simulations with long-term stability in spite of producing improvements in simulation lifetime when compared with unconstrained evolution. Constrained evolution is also examined in conjunction with a wide variety of promising numerical techniques, including mesh refinement and overlapping Cartesian and spherical computational grids. Constrained evolution in boosted black hole spacetimes is investigated using overlapping grids. Constrained evolution proves to be central to the host of innovations required in carrying out such intensive simulations.
Continuous-variable quantum teleportation in bosonic structured environments
Energy Technology Data Exchange (ETDEWEB)
He Guangqiang; Zhang Jingtao; Zhu Jun; Zeng Guihua [State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200240 (China)
2011-09-15
The effects of dynamics of continuous-variable entanglement under the various kinds of environments on quantum teleportation are quantitatively investigated. Only under assumption of the weak system-reservoir interaction, the evolution of teleportation fidelity is analytically derived and is numerically plotted in terms of environment parameters including reservoir temperature and its spectral density, without Markovian and rotating wave approximations. We find that the fidelity of teleportation is a monotonically decreasing function for Markovian interaction in Ohmic-like environments, while it oscillates for non-Markovian ones. According to the dynamical laws of teleportation, teleportation with better performances can be implemented by selecting the appropriate time.
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.
International Nuclear Information System (INIS)
Bodvarsson, G.S.; Lippmann, M.J.
1980-01-01
The computer program CCC (conduction-convection-consolidation), developed at Lawrence Berkeley Laboratory, solves numerically the heat and mass flow equations for a fully saturated medium, and computes one-dimensional consolidation of the simulated systems. The model employs the Integrated Finite Difference Method (IFDM) in discretizing the saturated medium and formulating the governing equations. The sets of equations are solved either by an iterative solution technique (old version) or an efficient sparse solver (new version). The deformation of the medium is calculated using the one-dimensional consolidation theory of Terzaghi. In this paper, the numerical code is described, validation examples given and areas of application discussed. Several example problems involving flow through fractured media are also presented
Borcard, Daniel; Legendre, Pierre
2018-01-01
This new edition of Numerical Ecology with R guides readers through an applied exploration of the major methods of multivariate data analysis, as seen through the eyes of three ecologists. It provides a bridge between a textbook of numerical ecology and the implementation of this discipline in the R language. The book begins by examining some exploratory approaches. It proceeds logically with the construction of the key building blocks of most methods, i.e. association measures and matrices, and then submits example data to three families of approaches: clustering, ordination and canonical ordination. The last two chapters make use of these methods to explore important and contemporary issues in ecology: the analysis of spatial structures and of community diversity. The aims of methods thus range from descriptive to explanatory and predictive and encompass a wide variety of approaches that should provide readers with an extensive toolbox that can address a wide palette of questions arising in contemporary mul...
Numerical simulation in astrophysics
International Nuclear Information System (INIS)
Miyama, Shoken
1985-01-01
There have been many numerical simulations of hydrodynamical problems in astrophysics, e.g. processes of star formation, supernova explosion and formation of neutron stars, and general relativistic collapse of star to form black hole. The codes are made to be suitable for computing such problems. In astrophysical hydrodynamical problems, there are the characteristics: problems of self-gravity or external gravity acting, objects of scales very large or very short, objects changing by short period or long time scale, problems of magnetic force and/or centrifugal force acting. In this paper, we present one of methods of numerical simulations which may satisfy these requirements, so-called smoothed particle methods. We then introduce the methods briefly. Then, we show one of the applications of the methods to astrophysical problem (fragmentation and collapse of rotating isothermal cloud). (Mori, K.)
Hybrid undulator numerical optimization
Energy Technology Data Exchange (ETDEWEB)
Hairetdinov, A.H. [Kurchatov Institute, Moscow (Russian Federation); Zukov, A.A. [Solid State Physics Institute, Chernogolovka (Russian Federation)
1995-12-31
3D properties of the hybrid undulator scheme arc studied numerically using PANDIRA code. It is shown that there exist two well defined sets of undulator parameters which provide either maximum on-axis field amplitude or minimal higher harmonics amplitude of the basic undulator field. Thus the alternative between higher field amplitude or pure sinusoidal field exists. The behavior of the undulator field amplitude and harmonics structure for a large set of (undulator gap)/(undulator wavelength) values is demonstrated.
Comments on numerical simulations
International Nuclear Information System (INIS)
Sato, T.
1984-01-01
The author comments on a couple of things about numerical simulation. One is just about the philosophical discussion that is, spontaneous or driven. The other thing is the numerical or technical one. Frankly, the author didn't want to touch on the technical matter because this should be a common sense one for those who are working at numerical simulation. But since many people take numerical simulation results at their face value, he would like to remind you of the reality hidden behind them. First, he would point out that the meaning of ''driven'' in driven reconnection is different from that defined by Schindler or Akasofu. The author's definition is closer to Axford's definition. In the spontaneous case, for some unpredicted reason an excess energy of the system is suddenly released at a certain point. However, one does not answer how such an unstable state far beyond a stable limit is realized in the magnetotail. In the driven case, there is a definite energy buildup phase starting from a stable state; namely, energy in the black box increases from a stable level subject to an external source. When the state has reached a certain position, the energy is released suddenly. The difference between driven and spontaneous is whether the cause (plasma flow) to trigger reconnection is specified or reconnection is triggered unpredictably. Another difference is that in driven reconnection the reconnection rate is dependent on the speed of the external plasma flow, but in spontaneous reconnection the rate is dependent on the internal condition such as the resistivity
Numerical simulation of plasmas
International Nuclear Information System (INIS)
Dnestrovskii, Y.N.; Kostomarov, D.P.
1986-01-01
This book contains a modern consistent and systematic presentation of numerical computer simulation of plasmas in controlled thermonuclear fusion. The authors focus on the Soviet research in mathematical modelling of Tokamak plasmas, and present kinetic hydrodynamic and transport models with special emphasis on the more recent hybrid models. Compared with the first edition (in Russian) this book has been greatly revised and updated. (orig./WL)
Numerical analysis II essentials
REA, The Editors of; Staff of Research Education Association
1989-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Numerical Analysis II covers simultaneous linear systems and matrix methods, differential equations, Fourier transformations, partial differential equations, and Monte Carlo methods.
Efficient Numerical Simulation of Aerothermoelastic Hypersonic Vehicles
Klock, Ryan J.
Hypersonic vehicles operate in a high-energy flight environment characterized by high dynamic pressures, high thermal loads, and non-equilibrium flow dynamics. This environment induces strong fluid, thermal, and structural dynamics interactions that are unique to this flight regime. If these vehicles are to be effectively designed and controlled, then a robust and intuitive understanding of each of these disciplines must be developed not only in isolation, but also when coupled. Limitations on scaling and the availability of adequate test facilities mean that physical investigation is infeasible. Ever growing computational power offers the ability to perform elaborate numerical simulations, but also has its own limitations. The state of the art in numerical simulation is either to create ever more high-fidelity physics models that do not couple well and require too much processing power to consider more than a few seconds of flight, or to use low-fidelity analytical models that can be tightly coupled and processed quickly, but do not represent realistic systems due to their simplifying assumptions. Reduced-order models offer a middle ground by distilling the dominant trends of high-fidelity training solutions into a form that can be quickly processed and more tightly coupled. This thesis presents a variably coupled, variable-fidelity, aerothermoelastic framework for the simulation and analysis of high-speed vehicle systems using analytical, reduced-order, and surrogate modeling techniques. Full launch-to-landing flights of complete vehicles are considered and used to define flight envelopes with aeroelastic, aerothermal, and thermoelastic limits, tune in-the-loop flight controllers, and inform future design considerations. A partitioned approach to vehicle simulation is considered in which regions dominated by particular combinations of processes are made separate from the overall solution and simulated by a specialized set of models to improve overall processing
Renovation and Strengthening of Wooden Beams With CFRP Bands Including the Rheological Effects
Directory of Open Access Journals (Sweden)
Kula Krzysztof
2016-09-01
Full Text Available The paper presents a work analysis of wooden beams reinforced with glued composite bands from the top and resin inclusions, taking into account the rheology of materials. The paper presents numerical model of the multimaterial beam work including rheological phenomena described by linear equations of viscoelasticity. For the construction of this model one used MES SIMULIA ABAQUS environment in which were prepared its own procedures containing rheological models. The calculation results were compared with the literature data. One has done an analysis of the advisability of the use of CFRP reinforcements bands in terms of rheological phenomena.
Virtual Environments for Training
National Research Council Canada - National Science Library
Stiles, R
1998-01-01
.... Progress on productization of the VET Training Studio software includes increased robustness for Vista virtual environment display and interaction services, a new capability to use the STEVE visual...
Numerical methods in simulation of resistance welding
DEFF Research Database (Denmark)
Nielsen, Chris Valentin; Martins, Paulo A.F.; Zhang, Wenqi
2015-01-01
Finite element simulation of resistance welding requires coupling betweenmechanical, thermal and electrical models. This paper presents the numerical models and theircouplings that are utilized in the computer program SORPAS. A mechanical model based onthe irreducible flow formulation is utilized...... a resistance welding point of view, the most essential coupling between the above mentioned models is the heat generation by electrical current due to Joule heating. The interaction between multiple objects is anothercritical feature of the numerical simulation of resistance welding because it influences...... thecontact area and the distribution of contact pressure. The numerical simulation of resistancewelding is illustrated by a spot welding example that includes subsequent tensile shear testing...
Average-case analysis of numerical problems
2000-01-01
The average-case analysis of numerical problems is the counterpart of the more traditional worst-case approach. The analysis of average error and cost leads to new insight on numerical problems as well as to new algorithms. The book provides a survey of results that were mainly obtained during the last 10 years and also contains new results. The problems under consideration include approximation/optimal recovery and numerical integration of univariate and multivariate functions as well as zero-finding and global optimization. Background material, e.g. on reproducing kernel Hilbert spaces and random fields, is provided.
Numerical studies of the linear theta pinch
International Nuclear Information System (INIS)
Brackbill, J.U.; Menzel, M.T.; Barnes, D.C.
1975-01-01
Aspects of several physical problems associated with linear theta pinches were studied using recently developed numerical methods for the solution of the nonlinear equations for time-dependent magnetohydrodynamic flow in two- and three-dimensions. The problems studied include the propagation of end-loss produced rarefaction waves, the flow produced in a proposed injection experiment geometry, and the linear growth and nonlinear saturation of instabilities in rotating plasmas, all in linear geometries. The studies illustrate how numerical computations aid in flow visualization, and how the small amplitude behavior and nonlinear fate of plasmas in unstable equilibria can be connected through the numerical solution of the dynamical equations. (auth)
Coincidental match of numerical simulation and physics
Pierre, B.; Gudmundsson, J. S.
2010-08-01
Consequences of rapid pressure transients in pipelines range from increased fatigue to leakages and to complete ruptures of pipeline. Therefore, accurate predictions of rapid pressure transients in pipelines using numerical simulations are critical. State of the art modelling of pressure transient in general, and water hammer in particular include unsteady friction in addition to the steady frictional pressure drop, and numerical simulations rely on the method of characteristics. Comparison of rapid pressure transient calculations by the method of characteristics and a selected high resolution finite volume method highlights issues related to modelling of pressure waves and illustrates that matches between numerical simulations and physics are purely coincidental.
International Nuclear Information System (INIS)
Seiler, J.M.; Bonnet, J.M.; Bernaz, L.
2001-01-01
Extensive studies have been performed to investigate the heat transfer within a molten corium pool (homogeneous, stratified and with miscibility gap): Synthesis of heat transfer correlations in molten pool (homogeneous and stratified), Focusing effect in stratified metal layer, DNS analysis of Rayleigh Benard instabilities at the top boundary; interpretation of the different convection regimes and exponents affecting the Rayleigh number in the heat transfer correlations, Molten pool model for corium presenting a miscibility gap. Condition for de-stratification. (authors)
3D numerical surface charge model including relative permeability : the general theory
Casteren, van D.T.E.H.; Paulides, J.J.H.; Lomonova, E.A.
2014-01-01
One of the still "open" issues within low-frequency magnetics is the inclusion of µr in the calculations using the magnetic charge method. In this paper a new iterative method to take the relative permeability into account is investigated. Results show that the model accurately accounts for the
Energy Technology Data Exchange (ETDEWEB)
Seiler, J.M.; Bonnet, J.M.; Bernaz, L. [CEA Grenoble (France)
2001-07-01
Extensive studies have been performed to investigate the heat transfer within a molten corium pool (homogeneous, stratified and with miscibility gap): Synthesis of heat transfer correlations in molten pool (homogeneous and stratified), Focusing effect in stratified metal layer, DNS analysis of Rayleigh Benard instabilities at the top boundary; interpretation of the different convection regimes and exponents affecting the Rayleigh number in the heat transfer correlations, Molten pool model for corium presenting a miscibility gap. Condition for de-stratification. (authors)
Numerical Treatment of Two-phase Flow in Porous Media Including Specific Interfacial Area
El-Amin, Mohamed; Meftah, R.; Salama, Amgad; Sun, Shuyu
2015-01-01
-matrices method which can reduce the time-consuming operations. A new iterative implicit algorithm has been developed to solve the problem under consideration. All advection and advection-like terms that appear in saturation equation and interfacial area equation
Development of numerical dispersion model for radioactive nuclei including resuspension processes
International Nuclear Information System (INIS)
Chiba, Masaru; Kurita, Susumu; Sasaki, Hidetaka
2003-01-01
Global-scale and local-scale dispersion model are developed combining to global and local scale meteorological forecasting model. By applying this system to another miner constituent such as mineral dust blowing by strong wind in arid region, this system shows very good performance to watch and predict the distribution of it. (author)
Aerosol simulation including chemical and nuclear reactions
International Nuclear Information System (INIS)
Marwil, E.S.; Lemmon, E.C.
1985-01-01
The numerical simulation of aerosol transport, including the effects of chemical and nuclear reactions presents a challenging dynamic accounting problem. Particles of different sizes agglomerate and settle out due to various mechanisms, such as diffusion, diffusiophoresis, thermophoresis, gravitational settling, turbulent acceleration, and centrifugal acceleration. Particles also change size, due to the condensation and evaporation of materials on the particle. Heterogeneous chemical reactions occur at the interface between a particle and the suspending medium, or a surface and the gas in the aerosol. Homogeneous chemical reactions occur within the aersol suspending medium, within a particle, and on a surface. These reactions may include a phase change. Nuclear reactions occur in all locations. These spontaneous transmutations from one element form to another occur at greatly varying rates and may result in phase or chemical changes which complicate the accounting process. This paper presents an approach for inclusion of these effects on the transport of aerosols. The accounting system is very complex and results in a large set of stiff ordinary differential equations (ODEs). The techniques for numerical solution of these ODEs require special attention to achieve their solution in an efficient and affordable manner. 4 refs
Uncertainty Quantification in Numerical Aerodynamics
Litvinenko, Alexander
2017-05-16
We consider uncertainty quantification problem in aerodynamic simulations. We identify input uncertainties, classify them, suggest an appropriate statistical model and, finally, estimate propagation of these uncertainties into the solution (pressure, velocity and density fields as well as the lift and drag coefficients). The deterministic problem under consideration is a compressible transonic Reynolds-averaged Navier-Strokes flow around an airfoil with random/uncertain data. Input uncertainties include: uncertain angle of attack, the Mach number, random perturbations in the airfoil geometry, mesh, shock location, turbulence model and parameters of this turbulence model. This problem requires efficient numerical/statistical methods since it is computationally expensive, especially for the uncertainties caused by random geometry variations which involve a large number of variables. In numerical section we compares five methods, including quasi-Monte Carlo quadrature, polynomial chaos with coefficients determined by sparse quadrature and gradient-enhanced version of Kriging, radial basis functions and point collocation polynomial chaos, in their efficiency in estimating statistics of aerodynamic performance upon random perturbation to the airfoil geometry [D.Liu et al \\'17]. For modeling we used the TAU code, developed in DLR, Germany.
Configuration Management File Manager Developed for Numerical Propulsion System Simulation
Follen, Gregory J.
1997-01-01
One of the objectives of the High Performance Computing and Communication Project's (HPCCP) Numerical Propulsion System Simulation (NPSS) is to provide a common and consistent way to manage applications, data, and engine simulations. The NPSS Configuration Management (CM) File Manager integrated with the Common Desktop Environment (CDE) window management system provides a common look and feel for the configuration management of data, applications, and engine simulations for U.S. engine companies. In addition, CM File Manager provides tools to manage a simulation. Features include managing input files, output files, textual notes, and any other material normally associated with simulation. The CM File Manager includes a generic configuration management Application Program Interface (API) that can be adapted for the configuration management repositories of any U.S. engine company.
DEFF Research Database (Denmark)
Møhlenberg, Flemming; Christensen, Erik Damgaard
2015-01-01
. The planning and design of MUPS in MERMAID has therefore not only involved standard engineering methods, but also advanced numerical tools, that can enable a detailed understanding of the environment and the interactions between the MUP and the surrounding water environments. The intention of this report...... is to summarise the advanced methods developed and used during MERMAID to support the planning and design of MUP’s and form a guideline and inspiration to planners on how to meet the challenges that turns up during design of such structures....
Extreme environment electronics
Cressler, John D
2012-01-01
Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp
Qubits in a random environment
International Nuclear Information System (INIS)
Akhalwaya, I; Fannes, M; Petruccione, F
2007-01-01
Decoherence phenomena in a small quantum system coupled to a complex environment can be modelled with random matrices. We propose a simple deterministic model in the limit of a high dimensional environment. The model is investigated numerically and some analytically addressable questions are singled out
Perinatal risk factors including malformation
International Nuclear Information System (INIS)
Brachner, A.; Grosche, B.
1991-10-01
The study gives a survey of the factors most frequently mentioned in the literature as factors likely to adversely affect a pregnancy. One essential aspect is the discussion of those factors that can be counted among the causes of malformations, as among others, prenatal radiation exposure. The study prepared within the framework of the research project 'Radiobiological environmental monitoring in Bavaria' is intended to serve as a basis for a retrospective and prospective evaluation of infant mortality, perinatal conditions and occurrence of malformations in Bavaria, with the principal idea of drawing up an environment - related health survey. The study therefore, in addition to ionizing radiation also takes into account other detectable risks within the ecologic context, as e.g. industrial installations, refuse incineration plants or waste dumps, or urbanity. (orig./MG) [de
A literature survey on numerical heat transfer
Shih, T. M.
1982-12-01
Technical papers in the area of numerical heat transfer published from 1977 through 1981 are reviewed. The journals surveyed include: (1) ASME Journal of Heat Transfer, (2) International Journal of Heat and Mass Transfer, (3) AIAA Journal, (4) Numerical Heat Transfer, (5) Computers and Fluids, (6) International Journal for Numerical Methods in Engineering, (7) SIAM Journal of Numerical Analysis, and (8) Journal of Computational Physics. This survey excludes experimental work in heat transfer and numerical schemes that are not applied to equations governing heat transfer phenomena. The research work is categorized into the following areas: (A) conduction, (B) boundary-layer flows, (C) momentum and heat transfer in cavities, (D) turbulent flows, (E) convection around cylinders and spheres or within annuli, (F) numerical convective instability, (G) radiation, (H) combustion, (I) plumes, jets, and wakes, (J) heat transfer in porous media, (K) boiling, condensation, and two-phase flows, (L) developing and fully developed channel flows, (M) combined heat and mass transfer, (N) applications, (O) comparison and properties of numerical schemes, and (P) body-fitted coordinates and nonuniform grids.
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.
Numerical Modelling of Flow and Settling in Secondary Settling Tanks
DEFF Research Database (Denmark)
Dahl, Claus Poulsen
This thesis discusses the development of a numerical model for the simulation of secondary settling tanks. In the first part, the status on the development of numerical models for settling tanks and a discussion of the current design practice are presented. A study of the existing numerical models...... and design practice proved a demand for further development to include numerical models in the design of settling tanks, thus improving the future settling tanks....
Langevin simulations of QCD, including fermions
International Nuclear Information System (INIS)
Kronfeld, A.S.
1986-02-01
We encounter critical slow down in updating when xi/a -> infinite and in matrix inversion (needed to include fermions) when msub(q)a -> 0. A simulation that purports to solve QCD numerically will encounter these limits, so to face the challenge in the title of this workshop, we must cure the disease of critical slow down. Physically, this critical slow down is due to the reluctance of changes at short distances to propagate to large distances. Numerically, the stability of an algorithm at short wavelengths requires a (moderately) small step size; critical slow down occurs when the effective long wavelength step size becomes tiny. The remedy for this disease is an algorithm that propagates signals quickly throughout the system; i.e. one whose effective step size is not reduced for the long wavelength conponents of the fields. (Here the effective ''step size'' is essentially an inverse decorrelation time.) To do so one must resolve various wavelengths of the system and modify the dynamics (in CPU time) of the simulation so that all modes evolve at roughly the same rate. This can be achieved by introducing Fourier transforms. I show how to implement Fourier acceleration for Langevin updating and for conjugate gradient matrix inversion. The crucial feature of these algorithms that lends them to Fourier acceleration is that they update the lattice globally; hence the Fourier transforms are computed once per sweep rather than once per hit. (orig./HSI)
Numerical relativity beyond astrophysics
Garfinkle, David
2017-01-01
Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.
Testability of numerical systems
International Nuclear Information System (INIS)
Soulas, B.
1992-01-01
In order to face up to the growing complexity of systems, the authors undertook to define a new approach for the qualification of systems. This approach is based on the concept of Testability which, supported by system modelization, validation and verification methods and tools, would allow Integrated Qualification process, applied throughout the life-span of systems. The general principles of this approach are introduced in the general case of numerical systems; in particular, this presentation points out the difference between the specification activity and the modelization and validation activity. This approach is illustrated firstly by the study of a global system and then by case of communication protocol as the software point of view. Finally MODEL which support this approach is described. MODEL tool is a commercial tool providing modelization and validation techniques based on Petri Nets with triple extension: Predicate/Transition, Timed and Stochastic Petri Nets
Numerical relativity beyond astrophysics.
Garfinkle, David
2017-01-01
Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.
Fluid dynamics theory, computation, and numerical simulation
Pozrikidis, C
2001-01-01
Fluid Dynamics Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes Two distinguishing features of the discourse are solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty Matlab codes are presented and discussed for a broad...
Fluid Dynamics Theory, Computation, and Numerical Simulation
Pozrikidis, Constantine
2009-01-01
Fluid Dynamics: Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner. The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming. This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice. There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes. Two distinguishing features of the discourse are: solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty. Matlab codes are presented and discussed for ...
International Nuclear Information System (INIS)
Kinare, Arun
2008-01-01
The intrauterine environment has a strong influence on pregnancy outcome. The placenta and the umbilical cord together form the main supply line of the fetus. Amniotic fluid also serves important functions. These three main components decide whether there will be an uneventful pregnancy and the successful birth of a healthy baby. An insult to the intrauterine environment has an impact on the programming of the fetus, which can become evident in later life, mainly in the form of cardiovascular diseases, diabetes, and certain learning disabilities. The past two decades have witnessed major contributions from researchers in this field, who have included ultrasonologists, epidemiologists, neonatologists, and pediatricians. Besides being responsible for these delayed postnatal effects, abnormalities of the placenta, umbilical cord, and amniotic fluid also have associations with structural and chromosomal disorders. Population and race also influence pregnancy outcomes to some extent in certain situations. USG is the most sensitive imaging tool currently available for evaluation of these factors and can offer considerable information in this area. This article aims at reviewing the USG-related developments in this area and the anatomy, physiology, and various pathologies of the placenta, umbilical cord, and the amniotic fluid
Computing the Alexander Polynomial Numerically
DEFF Research Database (Denmark)
Hansen, Mikael Sonne
2006-01-01
Explains how to construct the Alexander Matrix and how this can be used to compute the Alexander polynomial numerically.......Explains how to construct the Alexander Matrix and how this can be used to compute the Alexander polynomial numerically....
Corinne Pralavorio
2016-01-01
New webpages answer common questions about CERN and the environment. One of the new public webpages dedicated to CERN and the environment. Do your neighbours ever ask you about CERN’s environmental impact? And about radiation in particular? If so, the answers to those questions can now be found online on a new set of public webpages dedicated to CERN and the environment. These pages, put together by the Occupational Health, Safety and Environmental Protection (HSE) unit and the groups responsible for CERN's site maintenance, contain a wealth of information on topics linked to the environment, such as biodiversity at CERN, waste management, ionising radiation, and water and electricity consumption. “CERN forms part of the local landscape, with its numerous sites and scientific activities. It’s understandable that people living nearby have questions about the impact of these activities and it’s important that we respond with complete transp...
Visualization Design Environment
Energy Technology Data Exchange (ETDEWEB)
Pomplun, A.R.; Templet, G.J.; Jortner, J.N.; Friesen, J.A.; Schwegel, J.; Hughes, K.R.
1999-02-01
Improvements in the performance and capabilities of computer software and hardware system, combined with advances in Internet technologies, have spurred innovative developments in the area of modeling, simulation and visualization. These developments combine to make it possible to create an environment where engineers can design, prototype, analyze, and visualize components in virtual space, saving the time and expenses incurred during numerous design and prototyping iterations. The Visualization Design Centers located at Sandia National Laboratories are facilities built specifically to promote the ''design by team'' concept. This report focuses on designing, developing and deploying this environment by detailing the design of the facility, software infrastructure and hardware systems that comprise this new visualization design environment and describes case studies that document successful application of this environment.
(including travel dates) Proposed itinerary
Indian Academy of Sciences (India)
Ashok
31 July to 22 August 2012 (including travel dates). Proposed itinerary: Arrival in Bangalore on 1 August. 1-5 August: Bangalore, Karnataka. Suggested institutions: Indian Institute of Science, Bangalore. St Johns Medical College & Hospital, Bangalore. Jawaharlal Nehru Centre, Bangalore. 6-8 August: Chennai, TN.
Susy theories and QCD: numerical approaches
International Nuclear Information System (INIS)
Ita, Harald
2011-01-01
We review on-shell and unitarity methods and discuss their application to precision predictions for Large Hadron Collider (LHC) physics. Being universal and numerically robust, these methods are straightforward to automate for next-to-leading-order computations within standard model and beyond. Several state-of-the-art results including studies of (W/Z+3)-jet and (W+4)-jet production have explicitly demonstrated the effectiveness of the unitarity method for describing multi-parton scattering. Here we review central ideas needed to obtain efficient numerical implementations. This includes on-shell loop-level recursions, the unitarity method, color management and further refined tricks. (review)
Physical and Relativistic Numerical Cosmology.
Anninos, Peter
1998-01-01
In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations addressing specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark-hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.
Physical and Relativistic Numerical Cosmology
Directory of Open Access Journals (Sweden)
Peter Anninos
1998-01-01
Full Text Available In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations addressing specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark--hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.
Comprehensive numerical modelling of tokamaks
International Nuclear Information System (INIS)
Cohen, R.H.; Cohen, B.I.; Dubois, P.F.
1991-01-01
We outline a plan for the development of a comprehensive numerical model of tokamaks. The model would consist of a suite of independent, communicating packages describing the various aspects of tokamak performance (core and edge transport coefficients and profiles, heating, fueling, magnetic configuration, etc.) as well as extensive diagnostics. These codes, which may run on different computers, would be flexibly linked by a user-friendly shell which would allow run-time specification of packages and generation of pre- and post-processing functions, including workstation-based visualization of output. One package in particular, the calculation of core transport coefficients via gyrokinetic particle simulation, will become practical on the scale required for comprehensive modelling only with the advent of teraFLOP computers. Incremental effort at LLNL would be focused on gyrokinetic simulation and development of the shell
Numerical methods in matrix computations
Björck, Åke
2015-01-01
Matrix algorithms are at the core of scientific computing and are indispensable tools in most applications in engineering. This book offers a comprehensive and up-to-date treatment of modern methods in matrix computation. It uses a unified approach to direct and iterative methods for linear systems, least squares and eigenvalue problems. A thorough analysis of the stability, accuracy, and complexity of the treated methods is given. Numerical Methods in Matrix Computations is suitable for use in courses on scientific computing and applied technical areas at advanced undergraduate and graduate level. A large bibliography is provided, which includes both historical and review papers as well as recent research papers. This makes the book useful also as a reference and guide to further study and research work. Åke Björck is a professor emeritus at the Department of Mathematics, Linköping University. He is a Fellow of the Society of Industrial and Applied Mathematics.
Theory including future not excluded
DEFF Research Database (Denmark)
Nagao, K.; Nielsen, H.B.
2013-01-01
We study a complex action theory (CAT) whose path runs over not only past but also future. We show that, if we regard a matrix element defined in terms of the future state at time T and the past state at time TA as an expectation value in the CAT, then we are allowed to have the Heisenberg equation......, Ehrenfest's theorem, and the conserved probability current density. In addition,we showthat the expectation value at the present time t of a future-included theory for large T - t and large t - T corresponds to that of a future-not-included theory with a proper inner product for large t - T. Hence, the CAT...
Energy Technology Data Exchange (ETDEWEB)
Ishihara, O. [Kumamoto Univ. (Japan). Faculty of Engineering
1996-09-30
A case study for a natural energy system serving for a private house is reported with the outline of the system and the measurement results of the temperature and heat environments both in summer and winter. A 2-story house with an area of 141m{sup 2} and a total floor area of 186m{sup 2} is introduced including the site where it stands. Then, it is described on a floor heating system by circulating warm water through pipings embedded in the structural bodies, made of reinforced concrete from a solar heat collector consisted of 20 galvanized steel pipes of 100mm in diameter and 7m in length, a wall and ceiling cooling system with well water that gushes out at a rate of about 2 tons/min, and also the use of 20 amorphous solar cell panels as the source of electric power generation of about 17W capacity for these 2 systems, a house sewage disposal after the first stage treatment into the soil of kicken garden and so forth. Upon these system installed, 50 measurement items such as temperatures of outdoor and each room, humidity, quantity of sunshine and so on were measured for 1 year, and the instrumentation data were collected. From various analytical results, it was revealed that the highest temperature of warm water pipings in winter was 32{degree}C, while the lowest temperature of 17{degree}C was recorded in the morning and the surface temperature in the structural bodies of a room located at the south-east corner remained stable in summer more or less at 27{degree}C and so forth. 13 figs., 1 tab.
Numerical aerodynamic simulation (NAS)
International Nuclear Information System (INIS)
Peterson, V.L.; Ballhaus, W.F. Jr.; Bailey, F.R.
1984-01-01
The Numerical Aerodynamic Simulation (NAS) Program is designed to provide a leading-edge computational capability to the aerospace community. It was recognized early in the program that, in addition to more advanced computers, the entire computational process ranging from problem formulation to publication of results needed to be improved to realize the full impact of computational aerodynamics. Therefore, the NAS Program has been structured to focus on the development of a complete system that can be upgraded periodically with minimum impact on the user and on the inventory of applications software. The implementation phase of the program is now under way. It is based upon nearly 8 yr of study and should culminate in an initial operational capability before 1986. The objective of this paper is fivefold: 1) to discuss the factors motivating the NAS program, 2) to provide a history of the activity, 3) to describe each of the elements of the processing-system network, 4) to outline the proposed allocation of time to users of the facility, and 5) to describe some of the candidate problems being considered for the first benchmark codes
Towards numerical simulations of supersonic liquid jets using ghost fluid method
International Nuclear Information System (INIS)
Majidi, Sahand; Afshari, Asghar
2015-01-01
Highlights: • A ghost fluid method based solver is developed for numerical simulation of compressible multiphase flows. • The performance of the numerical tool is validated via several benchmark problems. • Emergence of supersonic liquid jets in quiescent gaseous environment is simulated using ghost fluid method for the first time. • Bow-shock formation ahead of the liquid jet is clearly observed in the obtained numerical results. • Radiation of mach waves from the phase-interface witnessed experimentally is evidently captured in our numerical simulations. - Abstract: A computational tool based on the ghost fluid method (GFM) is developed to study supersonic liquid jets involving strong shocks and contact discontinuities with high density ratios. The solver utilizes constrained reinitialization method and is capable of switching between the exact and approximate Riemann solvers to increase the robustness. The numerical methodology is validated through several benchmark test problems; these include one-dimensional multiphase shock tube problem, shock–bubble interaction, air cavity collapse in water, and underwater-explosion. A comparison between our results and numerical and experimental observations indicate that the developed solver performs well investigating these problems. The code is then used to simulate the emergence of a supersonic liquid jet into a quiescent gaseous medium, which is the very first time to be studied by a ghost fluid method. The results of simulations are in good agreement with the experimental investigations. Also some of the famous flow characteristics, like the propagation of pressure-waves from the liquid jet interface and dependence of the Mach cone structure on the inlet Mach number, are reproduced numerically. The numerical simulations conducted here suggest that the ghost fluid method is an affordable and reliable scheme to study complicated interfacial evolutions in complex multiphase systems such as supersonic liquid
Towards standard testbeds for numerical relativity
International Nuclear Information System (INIS)
Alcubierre, Miguel; Allen, Gabrielle; Bona, Carles; Fiske, David; Goodale, Tom; Guzman, F Siddhartha; Hawke, Ian; Hawley, Scott H; Husa, Sascha; Koppitz, Michael; Lechner, Christiane; Pollney, Denis; Rideout, David; Salgado, Marcelo; Schnetter, Erik; Seidel, Edward; Shinkai, Hisa-aki; Shoemaker, Deirdre; Szilagyi, Bela; Takahashi, Ryoji; Winicour, Jeff
2004-01-01
In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community for decades. Some of these approaches have been tested on different spacetimes, and conclusions have been drawn based on these tests. However, differences in results originate from many sources, including not only formulations of the equations, but also gauges, boundary conditions, numerical methods and so on. We propose to build up a suite of standardized testbeds for comparing approaches to the numerical evolution of Einstein's equations that are designed to both probe their strengths and weaknesses and to separate out different effects, and their causes, seen in the results. We discuss general design principles of suitable testbeds, and we present an initial round of simple tests with periodic boundary conditions. This is a pivotal first step towards building a suite of testbeds to serve the numerical relativists and researchers from related fields who wish to assess the capabilities of numerical relativity codes. We present some examples of how these tests can be quite effective in revealing various limitations of different approaches, and illustrating their differences. The tests are presently limited to vacuum spacetimes, can be run on modest computational resources and can be used with many different approaches used in the relativity community
Towards standard testbeds for numerical relativity
Energy Technology Data Exchange (ETDEWEB)
Alcubierre, Miguel [Inst. de Ciencias Nucleares, Univ. Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico); Allen, Gabrielle; Goodale, Tom; Guzman, F Siddhartha; Hawke, Ian; Husa, Sascha; Koppitz, Michael; Lechner, Christiane; Pollney, Denis; Rideout, David [Max-Planck-Inst. fuer Gravitationsphysik, Albert-Einstein-Institut, 14476 Golm (Germany); Bona, Carles [Departament de Fisica, Universitat de les Illes Balears, Ctra de Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Fiske, David [Dept. of Physics, Univ. of Maryland, College Park, MD 20742-4111 (United States); Hawley, Scott H [Center for Relativity, Univ. of Texas at Austin, Austin, Texas 78712 (United States); Salgado, Marcelo [Inst. de Ciencias Nucleares, Univ. Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico); Schnetter, Erik [Inst. fuer Astronomie und Astrophysik, Universitaet Tuebingen, 72076 Tuebingen (Germany); Seidel, Edward [Max-Planck-Inst. fuer Gravitationsphysik, Albert-Einstein-Inst., 14476 Golm (Germany); Shinkai, Hisa-aki [Computational Science Div., Inst. of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Shoemaker, Deirdre [Center for Radiophysics and Space Research, Cornell Univ., Ithaca, NY 14853 (United States); Szilagyi, Bela [Dept. of Physics and Astronomy, Univ. of Pittsburgh, Pittsburgh, PA 15260 (United States); Takahashi, Ryoji [Theoretical Astrophysics Center, Juliane Maries Vej 30, 2100 Copenhagen, (Denmark); Winicour, Jeff [Max-Planck-Inst. fuer Gravitationsphysik, Albert-Einstein-Institut, 14476 Golm (Germany)
2004-01-21
In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community for decades. Some of these approaches have been tested on different spacetimes, and conclusions have been drawn based on these tests. However, differences in results originate from many sources, including not only formulations of the equations, but also gauges, boundary conditions, numerical methods and so on. We propose to build up a suite of standardized testbeds for comparing approaches to the numerical evolution of Einstein's equations that are designed to both probe their strengths and weaknesses and to separate out different effects, and their causes, seen in the results. We discuss general design principles of suitable testbeds, and we present an initial round of simple tests with periodic boundary conditions. This is a pivotal first step towards building a suite of testbeds to serve the numerical relativists and researchers from related fields who wish to assess the capabilities of numerical relativity codes. We present some examples of how these tests can be quite effective in revealing various limitations of different approaches, and illustrating their differences. The tests are presently limited to vacuum spacetimes, can be run on modest computational resources and can be used with many different approaches used in the relativity community.
Extraction of gravitational waves in numerical relativity.
Bishop, Nigel T; Rezzolla, Luciano
2016-01-01
A numerical-relativity calculation yields in general a solution of the Einstein equations including also a radiative part, which is in practice computed in a region of finite extent. Since gravitational radiation is properly defined only at null infinity and in an appropriate coordinate system, the accurate estimation of the emitted gravitational waves represents an old and non-trivial problem in numerical relativity. A number of methods have been developed over the years to "extract" the radiative part of the solution from a numerical simulation and these include: quadrupole formulas, gauge-invariant metric perturbations, Weyl scalars, and characteristic extraction. We review and discuss each method, in terms of both its theoretical background as well as its implementation. Finally, we provide a brief comparison of the various methods in terms of their inherent advantages and disadvantages.
Numerical schemes for explosion hazards
International Nuclear Information System (INIS)
Therme, Nicolas
2015-01-01
In nuclear facilities, internal or external explosions can cause confinement breaches and radioactive materials release in the environment. Hence, modeling such phenomena is crucial for safety matters. Blast waves resulting from explosions are modeled by the system of Euler equations for compressible flows, whereas Navier-Stokes equations with reactive source terms and level set techniques are used to simulate the propagation of flame front during the deflagration phase. The purpose of this thesis is to contribute to the creation of efficient numerical schemes to solve these complex models. The work presented here focuses on two major aspects: first, the development of consistent schemes for the Euler equations, then the buildup of reliable schemes for the front propagation. In both cases, explicit in time schemes are used, but we also introduce a pressure correction scheme for the Euler equations. Staggered discretization is used in space. It is based on the internal energy formulation of the Euler system, which insures its positivity and avoids tedious discretization of the total energy over staggered grids. A discrete kinetic energy balance is derived from the scheme and a source term is added in the discrete internal energy balance equation to preserve the exact total energy balance at the limit. High order methods of MUSCL type are used in the discrete convective operators, based solely on material velocity. They lead to positivity of density and internal energy under CFL conditions. This ensures that the total energy cannot grow and we can furthermore derive a discrete entropy inequality. Under stability assumptions of the discrete L8 and BV norms of the scheme's solutions one can prove that a sequence of converging discrete solutions necessarily converges towards the weak solution of the Euler system. Besides it satisfies a weak entropy inequality at the limit. Concerning the front propagation, we transform the flame front evolution equation (the so called
Device including a contact detector
DEFF Research Database (Denmark)
2011-01-01
arms (12) may extend from the supporting body in co-planar relationship with the first surface. The plurality of cantilever arms (12) may extend substantially parallel to each other and each of the plurality of cantilever arms (12) may include an electrical conductive tip for contacting the area......The present invention relates to a probe for determining an electrical property of an area of a surface of a test sample, the probe is intended to be in a specific orientation relative to the test sample. The probe may comprise a supporting body defining a first surface. A plurality of cantilever...... of the test sample by movement of the probe relative to the surface of the test sample into the specific orientation.; The probe may further comprise a contact detector (14) extending from the supporting body arranged so as to contact the surface of the test sample prior to any one of the plurality...
Are We Pests? Microbial Genocide: The Effects of Abundant Use on the Environment
Pacheco, Eric
2017-01-01
This research reviews a copious amount of agricultural studies in which the effects (pros & cons) of pesticide use on the environment are measured. A pesticide is any substance used to kill, repel, or control certain forms of plant or animal life that are considered to be pests. Pesticides affect the environment in numerous ways such as: contamination of soil, water, and vegetation. In addition, pesticides are toxic to many organisms including fish, birds, beneficial insects, and even humans....
Numerical simulation of sand jet in water
Energy Technology Data Exchange (ETDEWEB)
Azimi, A.H.; Zhu, D.; Rajaratnam, N. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering
2008-07-01
A numerical simulation of sand jet in water was presented. The study involved a two-phase flow using two-phase turbulent jets. A literature review was also presented, including an experiment on particle laden air jet using laser doppler velocimetry (LDV); experiments on the effect of particle size and concentration on solid-gas jets; an experimental study of solid-liquid jets using particle image velocimetry (PIV) technique where mean velocity and fluctuations were measured; and an experimental study on solid-liquid jets using the laser doppler anemometry (LDA) technique measuring both water axial and radial velocities. Other literature review results included a photographic study of sand jets in water; a comparison of many two-phase turbulent flow; and direct numerical simulation and large-eddy simulation to study the effect of particle in gas jet flow. The mathematical model and experimental setup were also included in the presentation along with simulation results for sand jets, concentration, and kinetic energy. The presentation concluded with some proposed future studies including numerical simulation of slurry jets in water and numerical simulation of slurry jets in MFT. tabs., figs.
Simple Numerical Simulation of Strain Measurement
Tai, H.
2002-01-01
By adopting the basic principle of the reflection (and transmission) of a plane polarized electromagnetic wave incident normal to a stack of films of alternating refractive index, a simple numerical code was written to simulate the maximum reflectivity (transmittivity) of a fiber optic Bragg grating corresponding to various non-uniform strain conditions including photo-elastic effect in certain cases.
Numerical modelling of fuel sprays
Energy Technology Data Exchange (ETDEWEB)
Bergstroem, C.
1999-06-01
The way the fuel is introduced into the combustion chamber is one of the most important parameters for the power output and the generation of emissions in the combustion of liquid fuels. The interaction between the turbulent gas flow field and the liquid fuel droplets, the vaporisation of them and the mixing of the gaseous fuel with the ambient air that are vital parameters in the combustion process. The use of numerical calculations is an important tool to better understand these complex interacting phenomena. This thesis reports on the numerical modelling of fuel sprays in non-reacting cases using an own developed spray module. The spray module uses the stochastic parcel method to represent the spray. The module was made in such manner that it could by coupled with different gas flow solver. Results obtained from four different gas flow solvers are presented in the thesis, including the use of two different kinds of turbulence models. In the first part the spray module is coupled with a k-{eta} based 2-D cylindrical gas flow solver. A thorough sensitivity analysis was performed on the spray and gas flow solver parameters, such as grid size dependence and sensitivity to initial values of k-{eta}. The results of the spray module were also compared to results from other spray codes, e.g. the well known KIVA code. In the second part of this thesis the spray was injected into a turbulent and fully developed crossflow studied. The spray module was attached to a LES (Large Eddy Simulation) based flow solvers enabling the study of the complex structures and time dependent phenomena involved in spray in crossflows. It was found that the spray performs an oscillatory motion and that the Strouhal number in the wake was about 0.1. Different spray breakup models were evaluated by comparing with experimental results 66 refs, 56 figs
Fermi UNIX trademark environment
International Nuclear Information System (INIS)
Nicholls, J.
1991-03-01
The introduction of UNIX at Fermilab involves multiple platforms and multiple vendors. Additionally, a single user may have to use more than one platform. This heterogeneity and multiplicity makes it necessary to define a Fermilab environment for UNIX so that as much as possible the systems ''look and feel'' the same. We describe our environment, including both the commercial products and the local tools used to support it. Other products designed for the UNIX environment are also described. 19 refs
Camilleri, Mark Anthony
2017-01-01
The tourism marketing environment consists of internal and external forces which could impact the organisations’ performance. To be successful, companies must adapt to ongoing trends and developments in their macro and micro environments. When organisations scan their marketing environment they will be in a position to deal with any possible threats from the market and to capitalise on any available opportunities. Therefore, this chapter explains the external environmental factors, including;...
Japan and the global environment
International Nuclear Information System (INIS)
Miller, A.S.; Moore, C.
1993-01-01
In many areas, the word most often used to describe Japanese policy is open-quotes enigma.close quotes In some ways, Japan's record on environmental policy also has elements of mystery and contradiction. On the one hand, Japan's history and culture often are associated with a reverence for nature. Indeed, Japan does lead the world in certain environmental areas, such as reduction of conventional air pollutants and compensation of air pollution victims. On the other hand, Japan has been widely criticized for its poor record in preserving its domestic environment, contribution to tropical deforestation, and unwillingness to protect endangered species. Today, the international community clamors for Japan to take its share of responsibility, as an economic superpower, for the global environment. To secure its place in world affairs, Japan slowly has begun to respond to this pressure on issues ranging from ivory importation to reduction of CFC emissions. There is some hope that the government's particular willingness to address global warming may be a sign of significant changes to come in Japanese environmental policy. However, international pressure remains on the many environmental issues Japan has yet to resolve, including tropical deforestation and financing of Third World development projects that harm the environment. Japan's environmental policy is most effective when government and industry cooperate to find technical solutions to environmental problems. Although in recent years Japan's energy consumption has risen sharply, the Japanese have developed numerous technologies to reduce pollution and increase economic growth by improving energy efficiency. It is in these technologies that Japan has made the greatest strides and has the most to offer the global environment
International environment, enterprise environment and energy environment giving different look
Energy Technology Data Exchange (ETDEWEB)
Kubo, Shunsuke
1987-04-01
0he international environment, enterprise environment and energy environment surrounding Japan are changing their looks. In such situation, what Japan should do for the development of the world was discussed. Internationally, in the Western Pacific economical block including Japan and Asian NICs, Japan promotes the international exchange of materials, capital, technology, information and people, and creates various international public properties. Enterprisers should have global mind, and cope with the internationalization, technical innovation and information orientation which are in progress at present through international exchange, interindustrial exchange, industry-university-government exchange and so on. In the aspect of energy environment, Japan carries out the technical development of energy conservation, energy, creation and the exploration of energy resources, in this way, contributes to the stabilization of energy in the world. (3 figs, 1 tab)
Contributions to reinforced concrete structures numerical simulations
International Nuclear Information System (INIS)
Badel, P.B.
2001-07-01
In order to be able to carry out simulations of reinforced concrete structures, it is necessary to know two aspects: the behaviour laws have to reflect the complex behaviour of concrete and a numerical environment has to be developed in order to avoid to the user difficulties due to the softening nature of the behaviour. This work deals with these two subjects. After an accurate estimation of two behaviour models (micro-plan and mesoscopic models), two damage models (the first one using a scalar variable, the other one a tensorial damage of the 2 order) are proposed. These two models belong to the framework of generalized standard materials, which renders their numerical integration easy and efficient. A method of load control is developed in order to make easier the convergence of the calculations. At last, simulations of industrial structures illustrate the efficiency of the method. (O.M.)
Numerical methods: Analytical benchmarking in transport theory
International Nuclear Information System (INIS)
Ganapol, B.D.
1988-01-01
Numerical methods applied to reactor technology have reached a high degree of maturity. Certainly one- and two-dimensional neutron transport calculations have become routine, with several programs available on personal computer and the most widely used programs adapted to workstation and minicomputer computational environments. With the introduction of massive parallelism and as experience with multitasking increases, even more improvement in the development of transport algorithms can be expected. Benchmarking an algorithm is usually not a very pleasant experience for the code developer. Proper algorithmic verification by benchmarking involves the following considerations: (1) conservation of particles, (2) confirmation of intuitive physical behavior, and (3) reproduction of analytical benchmark results. By using today's computational advantages, new basic numerical methods have been developed that allow a wider class of benchmark problems to be considered
Numerical Modeling of Ocean Circulation
Miller, Robert N.
2007-01-01
The modelling of ocean circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of climate change. This book introduces the basic computational techniques necessary for all models of the ocean and atmosphere, and the conditions they must satisfy. It describes the workings of ocean models, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining ocean models critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of Oceanic and Atmospheric Sciences at Oregon State University, this book is ideal for graduate students of oceanography, geophysics, climatology and atmospheric science, and researchers in oceanography and atmospheric science. Features examples and critical examination of ocean modelling and results Demonstrates the strengths and weaknesses of different approaches Includes exercises to illustrate major points and supplement mathematical and physical details
Mycotoxins in the soil environment
Elmholt, S.
2008-01-01
The paper outlines the current knowledge concerning fate of mycotoxins in the soil environment, including - outline of mycotoxins addressed (trichothecenes, zearalenone, fumonisins, aflatoxins, ochratoxins and patulin) - routes by which the mycotoxins enter the soil environment - routes by which they are immobilised or removed from the soil environment - mycotoxigenic fungi and mycotoxins in the soil environment
Radioactivity in the environment
International Nuclear Information System (INIS)
Valkovic, V.
2000-01-01
Numerous sources of ionizing radiation can lead to human exposure: natural sources, nuclear explosions, nuclear power generation, use of radiation in medical, industrial and research purposes, and radiation emitting consumer products. Before assessing the radiation dose to a population one requires a precise knowledge of the activity of a number of radionuclides. The basis for the assessment of the dose to a population from a release of radioactivity to the environment, the estimation of the potential clinical heath effects due to the dose received and, ultimately, the implementation of countermeasures to protect the population, is the measurement of radioactive contamination in the environment after the release. It is the purpose of this book to present the facts about the presence of radionuclides in the environment, natural and man made. There is no aspect of radioactivity, which has marked the passing century, not mentioned or discussed in this book. refs
Numerical analysis in electromagnetics the TLM method
Saguet, Pierre
2013-01-01
The aim of this book is to give a broad overview of the TLM (Transmission Line Matrix) method, which is one of the "time-domain numerical methods". These methods are reputed for their significant reliance on computer resources. However, they have the advantage of being highly general.The TLM method has acquired a reputation for being a powerful and effective tool by numerous teams and still benefits today from significant theoretical developments. In particular, in recent years, its ability to simulate various situations with excellent precision, including complex materials, has been
Numerical orbit generators of artificial earth satellites
Kugar, H. K.; Dasilva, W. C. C.
1984-04-01
A numerical orbit integrator containing updatings and improvements relative to the previous ones that are being utilized by the Departmento de Mecanica Espacial e Controle (DMC), of INPE, besides incorporating newer modellings resulting from the skill acquired along the time is presented. Flexibility and modularity were taken into account in order to allow future extensions and modifications. Characteristics of numerical accuracy, processing quickness, memory saving as well as utilization aspects were also considered. User's handbook, whole program listing and qualitative analysis of accuracy, processing time and orbit perturbation effects were included as well.
Lecture notes in numerical analysis with Mathematica
Styś, Tadeusz
2014-01-01
The contents of this book include chapters on floating point computer arithmetic, natural and generalized interpolating polynomials, uniform approximation, numerical integration, polynomial splines and many more.This book is intended for undergraduate and graduate students in institutes, colleges, universities and academies who want to specialize in this field. The readers will develop a solid understanding of the concepts of numerical methods and their application. The inclusion of Lagrane and Hermite approximation by polynomials, Trapezian rule, Simpsons rule, Gauss methods and Romberg`s met
Including gauge corrections to thermal leptogenesis
Energy Technology Data Exchange (ETDEWEB)
Huetig, Janine
2013-05-17
. Furthermore, we have computed the Majorana neutrino production rate itself in chapter 6 to test our numerical procedure. In this context we have calculated the tree-level result as well as the gauge corrected result for the Majorana neutrino production rate. Finally in chapter 7, we have implemented the Majorana neutrino ladder rung diagram into our setup for leptogenesis: As a first consideration, we have collected all gauge corrected diagrams up to three-loop order for the asymmetry-causing two-loop diagrams. However, the results of chap. 5 showed that it is not sufficient to just include diagrams up to three-loop level. Due to the necessity of resumming all n-loop diagrams, we have constructed a cylindrical diagram that fulfils this condition. This diagram is the link between the Majorana neutrino ladder rung diagram calculated before on the one hand and the lepton asymmetry on the other. Therefore we have been able to derive a complete expression for the integrated lepton number matrix including all leading order corrections. The numerical analysis of this lepton number matrix needs a great computational effort since for the resulting eight-dimensional integral two ordinary differential equations have to be computed for each point the routine evaluates. Thus the result remains yet inaccessible. Research perspectives: Summarising, this thesis provides the basis for a systematic inclusion of gauge interactions in thermal leptogenesis scenarios. As a next step, one should evaluate the expression for the integrated lepton number numerically to gain a value, which can be used for comparison to earlier results such as the solutions of the Boltzmann equations as well as the Kadanoff-Baym ansatz with the implemented Standard Model widths. This numerical result would be the first quantitative number, which contains leading order corrections due to all interactions of the Majorana neutrino with the Standard Model particles. Further corrections by means of including washout effects
Including gauge corrections to thermal leptogenesis
International Nuclear Information System (INIS)
Huetig, Janine
2013-01-01
. Furthermore, we have computed the Majorana neutrino production rate itself in chapter 6 to test our numerical procedure. In this context we have calculated the tree-level result as well as the gauge corrected result for the Majorana neutrino production rate. Finally in chapter 7, we have implemented the Majorana neutrino ladder rung diagram into our setup for leptogenesis: As a first consideration, we have collected all gauge corrected diagrams up to three-loop order for the asymmetry-causing two-loop diagrams. However, the results of chap. 5 showed that it is not sufficient to just include diagrams up to three-loop level. Due to the necessity of resumming all n-loop diagrams, we have constructed a cylindrical diagram that fulfils this condition. This diagram is the link between the Majorana neutrino ladder rung diagram calculated before on the one hand and the lepton asymmetry on the other. Therefore we have been able to derive a complete expression for the integrated lepton number matrix including all leading order corrections. The numerical analysis of this lepton number matrix needs a great computational effort since for the resulting eight-dimensional integral two ordinary differential equations have to be computed for each point the routine evaluates. Thus the result remains yet inaccessible. Research perspectives: Summarising, this thesis provides the basis for a systematic inclusion of gauge interactions in thermal leptogenesis scenarios. As a next step, one should evaluate the expression for the integrated lepton number numerically to gain a value, which can be used for comparison to earlier results such as the solutions of the Boltzmann equations as well as the Kadanoff-Baym ansatz with the implemented Standard Model widths. This numerical result would be the first quantitative number, which contains leading order corrections due to all interactions of the Majorana neutrino with the Standard Model particles. Further corrections by means of including washout effects
Representation of Numerical and Non-Numerical Order in Children
Berteletti, Ilaria; Lucangeli, Daniela; Zorzi, Marco
2012-01-01
The representation of numerical and non-numerical ordered sequences was investigated in children from preschool to grade 3. The child's conception of how sequence items map onto a spatial scale was tested using the Number-to-Position task (Siegler & Opfer, 2003) and new variants of the task designed to probe the representation of the alphabet…
Numerical MHD study for plasmoid instability in uniform resistivity
Shimizu, Tohru; Kondoh, Koji; Zenitani, Seiji
2017-11-01
The plasmoid instability (PI) caused in uniform resistivity is numerically studied with a MHD numerical code of HLLD scheme. It is shown that the PI observed in numerical studies may often include numerical (non-physical) tearing instability caused by the numerical dissipations. By increasing the numerical resolutions, the numerical tearing instability gradually disappears and the physical tearing instability remains. Hence, the convergence of the numerical results is observed. Note that the reconnection rate observed in the numerical tearing instability can be higher than that of the physical tearing instability. On the other hand, regardless of the numerical and physical tearing instabilities, the tearing instability can be classified into symmetric and asymmetric tearing instability. The symmetric tearing instability tends to occur when the thinning of current sheet is stopped by the physical or numerical dissipations, often resulting in the drastic changes in plasmoid chain's structure and its activity. In this paper, by eliminating the numerical tearing instability, we could not specify the critical Lundquist number Sc beyond which PI is fully developed. It suggests that Sc does not exist, at least around S = 105.
Energy Technology Data Exchange (ETDEWEB)
Tornow, Sabine [Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universitaet Augsburg, 86135 Augsburg (Germany); Tong, Ning-Hua [Institut fuer Theorie der Kondensierten Materie, Universitaet Karlsruhe, 76128 Karlsruhe (Germany); Bulla, Ralf [Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universitaet Augsburg, 86135 Augsburg (Germany)
2006-07-05
We present a detailed model study of exciton transfer processes in donor-bridge-acceptor (DBA) systems. Using a model which includes the intermolecular Coulomb interaction and the coupling to a dissipative environment we calculate the phase diagram, the absorption spectrum as well as dynamic equilibrium properties with the numerical renormalization group. This method is non-perturbative and therefore allows one to cover the full parameter space, especially the case when the intermolecular Coulomb interaction is of the same order as the coupling to the environment and perturbation theory cannot be applied. For DBA systems with up to six sites we found a transition to the localized phase (self-trapping) depending on the coupling to the dissipative environment. We discuss various criteria which favour delocalized exciton transfer.
Tornow, Sabine; Tong, Ning-Hua; Bulla, Ralf
2006-07-05
We present a detailed model study of exciton transfer processes in donor-bridge-acceptor (DBA) systems. Using a model which includes the intermolecular Coulomb interaction and the coupling to a dissipative environment we calculate the phase diagram, the absorption spectrum as well as dynamic equilibrium properties with the numerical renormalization group. This method is non-perturbative and therefore allows one to cover the full parameter space, especially the case when the intermolecular Coulomb interaction is of the same order as the coupling to the environment and perturbation theory cannot be applied. For DBA systems with up to six sites we found a transition to the localized phase (self-trapping) depending on the coupling to the dissipative environment. We discuss various criteria which favour delocalized exciton transfer.
Numerical Modeling of Ablation Heat Transfer
Ewing, Mark E.; Laker, Travis S.; Walker, David T.
2013-01-01
A unique numerical method has been developed for solving one-dimensional ablation heat transfer problems. This paper provides a comprehensive description of the method, along with detailed derivations of the governing equations. This methodology supports solutions for traditional ablation modeling including such effects as heat transfer, material decomposition, pyrolysis gas permeation and heat exchange, and thermochemical surface erosion. The numerical scheme utilizes a control-volume approach with a variable grid to account for surface movement. This method directly supports implementation of nontraditional models such as material swelling and mechanical erosion, extending capabilities for modeling complex ablation phenomena. Verifications of the numerical implementation are provided using analytical solutions, code comparisons, and the method of manufactured solutions. These verifications are used to demonstrate solution accuracy and proper error convergence rates. A simple demonstration of a mechanical erosion (spallation) model is also provided to illustrate the unique capabilities of the method.
Numerical stability in problems of linear algebra.
Babuska, I.
1972-01-01
Mathematical problems are introduced as mappings from the space of input data to that of the desired output information. Then a numerical process is defined as a prescribed recurrence of elementary operations creating the mapping of the underlying mathematical problem. The ratio of the error committed by executing the operations of the numerical process (the roundoff errors) to the error introduced by perturbations of the input data (initial error) gives rise to the concept of lambda-stability. As examples, several processes are analyzed from this point of view, including, especially, old and new processes for solving systems of linear algebraic equations with tridiagonal matrices. In particular, it is shown how such a priori information can be utilized as, for instance, a knowledge of the row sums of the matrix. Information of this type is frequently available where the system arises in connection with the numerical solution of differential equations.
Numerical calculation of impurity charge state distributions
International Nuclear Information System (INIS)
Crume, E.C.; Arnurius, D.E.
1977-09-01
The numerical calculation of impurity charge state distributions using the computer program IMPDYN is discussed. The time-dependent corona atomic physics model used in the calculations is reviewed, and general and specific treatments of electron impact ionization and recombination are referenced. The complete program and two examples relating to tokamak plasmas are given on a microfiche so that a user may verify that his version of the program is working properly. In the discussion of the examples, the corona steady-state approximation is shown to have significant defects when the plasma environment, particularly the electron temperature, is changing rapidly
Chebfun and numerical quadrature
Hale, Nicholas; Trefethen, Lloyd N.
2012-01-01
Chebfun is a Matlab-based software system that overloads Matlab's discrete operations for vectors and matrices to analogous continuous operations for functions and operators. We begin by describing Chebfun's fast capabilities for Clenshaw-Curtis and also Gauss-Legendre, -Jacobi, -Hermite, and -Laguerre quadrature, based on algorithms of Waldvogel and Glaser, Liu and Rokhlin. Then we consider how such methods can be applied to quadrature problems including 2D integrals over rectangles, fractional derivatives and integrals, functions defined on unbounded intervals, and the fast computation of weights for barycentric interpolation. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.
Chebfun and numerical quadrature
Hale, Nicholas
2012-07-24
Chebfun is a Matlab-based software system that overloads Matlab\\'s discrete operations for vectors and matrices to analogous continuous operations for functions and operators. We begin by describing Chebfun\\'s fast capabilities for Clenshaw-Curtis and also Gauss-Legendre, -Jacobi, -Hermite, and -Laguerre quadrature, based on algorithms of Waldvogel and Glaser, Liu and Rokhlin. Then we consider how such methods can be applied to quadrature problems including 2D integrals over rectangles, fractional derivatives and integrals, functions defined on unbounded intervals, and the fast computation of weights for barycentric interpolation. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.
Numerical Analysis of Dusty-Gas Flows
Saito, T.
2002-02-01
This paper presents the development of a numerical code for simulating unsteady dusty-gas flows including shock and rarefaction waves. The numerical results obtained for a shock tube problem are used for validating the accuracy and performance of the code. The code is then extended for simulating two-dimensional problems. Since the interactions between the gas and particle phases are calculated with the operator splitting technique, we can choose numerical schemes independently for the different phases. A semi-analytical method is developed for the dust phase, while the TVD scheme of Harten and Yee is chosen for the gas phase. Throughout this study, computations are carried out on SGI Origin2000, a parallel computer with multiple of RISC based processors. The efficient use of the parallel computer system is an important issue and the code implementation on Origin2000 is also described. Flow profiles of both the gas and solid particles behind the steady shock wave are calculated by integrating the steady conservation equations. The good agreement between the pseudo-stationary solutions and those from the current numerical code validates the numerical approach and the actual coding. The pseudo-stationary shock profiles can also be used as initial conditions of unsteady multidimensional simulations.
Connected vehicle applications : environment.
2016-01-01
The U.S. Department of Transportation has developed a number of connected vehicle environmental applications, including the Applications for the Environment Real-Time Information Synthesis (AERIS) research program applications and road weather applic...
National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes presentation materials and outputs from operational space environment models produced by the NOAA Space Weather Prediction Center (SWPC) and...
Numerical Asymptotic Solutions Of Differential Equations
Thurston, Gaylen A.
1992-01-01
Numerical algorithms derived and compared with classical analytical methods. In method, expansions replaced with integrals evaluated numerically. Resulting numerical solutions retain linear independence, main advantage of asymptotic solutions.
Assessment of Combustor Working Environments
Directory of Open Access Journals (Sweden)
Leiyong Jiang
2012-01-01
Full Text Available In order to assess the remaining life of gas turbine critical components, it is vital to accurately define the aerothermodynamic working environments and service histories. As a part of a major multidisciplinary collaboration program, a benchmark modeling on a practical gas turbine combustor is successfully carried out, and the two-phase, steady, turbulent, compressible, reacting flow fields at both cruise and takeoff are obtained. The results show the complicated flow features inside the combustor. The airflow over each flow element of the combustor can or liner is not evenly distributed, and considerable variations, ±25%, around the average values, are observed. It is more important to note that the temperatures at the combustor can and cooling wiggle strips vary significantly, which can significantly affect fatigue life of engine critical components. The present study suggests that to develop an adequate aerothermodynamics tool, it is necessary to carry out a further systematic study, including validation of numerical results, simulations at typical engine operating conditions, and development of simple correlations between engine operating conditions and component working environments. As an ultimate goal, the cost and time of gas turbine engine fleet management must be significantly reduced.
How to Circumvent Church Numerals
DEFF Research Database (Denmark)
Goldberg, Mayer; Torgersen, Mads
2002-01-01
In this work we consider a standard numeral system in the lambda-calculus, and the elementary arithmetic and Boolean functions and predicates defined on this numeral system, and show how to construct terms that "circumvent" or "defeat" these functions: The equality predicate is satisfied when com...
Numerical Gram-Schmidt orthonormalization
International Nuclear Information System (INIS)
Werneth, Charles M; Dhar, Mallika; Maung, Khin Maung; Sirola, Christopher; Norbury, John W
2010-01-01
A numerical Gram-Schmidt orthonormalization procedure is presented for constructing an orthonormal basis function set from a non-orthonormal set, when the number of basis functions is large. This method will provide a pedagogical illustration of the Gram-Schmidt procedure and can be presented in classes on numerical methods or computational physics.
McLellan, Tom M.; Daanen, Hein A M; Cheung, Stephen S.
2013-01-01
In many occupational settings, clothing must be worn to protect individuals from hazards in their work environment. However, personal protective clothing (PPC) restricts heat exchange with the environment due to high thermal resistance and low water vapor permeability. As a consequence, individuals
McLellan, T.M.; Daanen, H.A.M.; Cheung, S.S.
2013-01-01
In many occupational settings, clothing must be worn to protect individuals from hazards in their work environment. However, personal protective clothing (PPC) restricts heat exchange with the environment due to high thermal resistance and low water vapor permeability. As a consequence, individuals
CERN Technical Training: LABVIEW courses include RADE
HR Department
2009-01-01
The contents of the "LabView Basic I" and "LabView Intermediate II" courses have recently been changed to include, respectively, an introduction to and expert training in the Rapid Application Development Environment (RADE). RADE is a LabView-based application developed at CERN to integrate LabView in the accelerator and experiment control infrastructure. It is a suitable solution to developing expert tools, machine development analysis and independent test facilities. The course names have also been changed to "LabVIEW Basics I with RADE Introduction" and "LabVIEW Intermediate II with Advanced RADE Application". " LabVIEW Basics I with RADE Introduction" is designed for: Users preparing to develop applications using LabVIEW, or NI Developer Suite; users and technical managers evaluating LabVIEW or NI Developer Suite in purchasing decisions; users pursuing the Certified LabVIEW Developer certification. The course pr...
CERN Technical Training: LABVIEW courses include RADE
HR Department
2009-01-01
The contents of the "LabView Basic I" and "LabView Intermediate II" courses have recently been changed to include, respectively, an introduction to and expert training in the Rapid Application Development Environment (RADE). RADE is a LabView-based application developed at CERN to integrate LabView in the accelerator and experiment control infrastructure. It is a suitable solution to developing expert tools, machine development analysis and independent test facilities. The course names have also been changed to "LabVIEW Basics I with RADE Introduction" and "LabVIEW Intermediate II with Advanced RADE Application". " LabVIEW Basics I with RADE Introduction" is designed for: Users preparing to develop applications using LabVIEW, or NI Developer Suite; users and technical managers evaluating LabVIEW or NI Developer Suite in purchasing decisions; users pursuing the Certified LabVIEW Developer certification. The course prepares participants to develop test and measurement, da...
CERN Technical Training: LABVIEW courses include RADE
HR Department
2009-01-01
The contents of "LabView Basic I" and "LabView Intermediate II" trainings have been recently changed to include, respectively, an introduction and an expert training on the Rapid Application Development Environment (RADE). RADE is a LabView-based application developed at CERN to integrate LabView in the accelerator and experiment control infrastructure. It is a suitable solution to develop expert tools, machine development analysis and independent test facilities. The course names have also been changed to "LabVIEW Basics I with RADE Introduction" and "LabVIEW Intermediate II with Advanced RADE Application". " LabVIEW Basics I with RADE Introduction" is designed for: Users preparing to develop applications using LabVIEW, or NI Developer Suite; users and technical managers evaluating LabVIEW or NI Developer Suite in purchasing decisions; users pursuing the Certified LabVIEW Developer certification. The course prepare...
Trade, Environment & Animal Welfare
DEFF Research Database (Denmark)
Morrison, Peter; Nielsen, Laura
2013-01-01
Regulation of animal welfare and the environment under the WTO GATT and GATS Agreements - including introduction of the innovative idea of limiting consumption abroad (mode 2) for e.g. bull fights.......Regulation of animal welfare and the environment under the WTO GATT and GATS Agreements - including introduction of the innovative idea of limiting consumption abroad (mode 2) for e.g. bull fights....
International Nuclear Information System (INIS)
Daisey, J.M.
1993-06-01
This paper reports progress during the year 1992 in the Indoor Environment Program in the Energy and Environment Division of Lawrence Berkeley Laboratory. Studies in the following areas are reported: energy performance and ventilation in buildings; physical and chemical characterization of indoor air pollutants; indoor radon; indoor air quality; exposure to indoor air pollutants and risk analysis. Pollutants of particular interest include: radon; volatile, semi-volatile and particulate organic compounds; and combustion emissions including environmental tobacco smoke, carbon monoxide, and nitrogen oxides
Numerical simulation of laser resonators
International Nuclear Information System (INIS)
Yoo, J. G.; Jeong, Y. U.; Lee, B. C.; Rhee, Y. J.; Cho, S. O.
2004-01-01
We developed numerical simulation packages for laser resonators on the bases of a pair of integral equations. Two numerical schemes, a matrix formalism and an iterative method, were programmed for finding numeric solutions to the pair of integral equations. The iterative method was tried by Fox and Li, but it was not applicable for high Fresnel numbers since the numerical errors involved propagate and accumulate uncontrollably. In this paper, we implement the matrix method to extend the computational limit further. A great number of case studies are carried out with various configurations of stable and unstable r;esonators to compute diffraction losses, phase shifts, intensity distributions and phases of the radiation fields on mirrors. Our results presented in this paper show not only a good agreement with the results previously obtained by Fox and Li, but also the legitimacy of our numerical procedures for high Fresnel numbers.
Organochlorine Pesticides in the Environment
Stickel, L.F.
1968-01-01
Each year for nearly 20 years, thousands of pounds of persistent organochlorine pesticides have been applied to outdoor areas in many countries. These compounds may last for a very long time in the environment, and be carried by wind, water, and animals to places far distant from where they are used. As a result, most living organisms now contain organochlorine residues. This paper constitutes a selective review of the literature concerning the occurrence, distribution, and effects of organochlorines in the environment. Highest concentrations generally occur in carnivorous species. Thus predatory and fish-eating birds ordinarily have higher residues than do herbivores; quantities are similar in birds of similar habits in different countries. Any segment of the ecosystem - marshland, pond, forest, or field - receives various amounts and kinds of pesticides at irregular intervals. The different animals absorb, detoxify, store, and excrete pesticides at different rates. Different degrees of magnification of pesticide residues by living organisms in an environment are the practical result of many interactions that are far more complex than implied by the statement of magnification up the food chain. These magnifications may be millions of times from water to mud or only a few times from food to first consumer. Direct mortality of wild animals as an aftermath of recommended pesticide treatments has been recorded in the literature of numerous countries. However, accidents and carelessness also accompany pesticide use on a percentage basis and are a part of the problem. More subtle effects on the size and species composition of populations are more difficult to perceive in time to effect remedies. The possibility of ecological effects being mediated through changes in physiology and behavior has received some attention and has resulted in some disquieting findings. These include discovery of the activity of organochlorines in stimulating the breakdown of hormones or in
Zγ production at NNLO including anomalous couplings
Campbell, John M.; Neumann, Tobias; Williams, Ciaran
2017-11-01
In this paper we present a next-to-next-to-leading order (NNLO) QCD calculation of the processes pp → l + l -γ and pp\\to ν \\overline{ν}γ that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of Zγγ and ZZγ anomalous couplings. We compare our implementation, obtained using the jettiness slicing approach, with a previous SM calculation and find broad agreement. Focusing on the sensitivity of our results to the slicing parameter, we show that using our setup we are able to compute NNLO cross sections with numerical uncertainties of about 0.1%, which is small compared to residual scale uncertainties of a few percent. We study potential improvements using two different jettiness definitions and the inclusion of power corrections. At √{s}=13 TeV we present phenomenological results and consider Zγ as a background to H → Zγ production. We find that, with typical cuts, the inclusion of NNLO corrections represents a small effect and loosens the extraction of limits on anomalous couplings by about 10%.
Numerical study of turbulent diffusion
International Nuclear Information System (INIS)
McCoy, M.G.
1975-01-01
The problem of the numerical simulation of turbulent diffusion is studied. The two-dimensional velocity fields are assumed to be incompressible, homogeneous and stationary, and they are represented as stochastic processes. A technique is offered which creates velocity fields accurately representing the input statistics once a two point correlation function or an energy spectrum is given. Various complicated energy spectra may be represented utilizing this model. The program is then used to extract information concerning Gaussian diffusion processes. Various theories of other workers are tested including Taylor's classical representation of dispersion for times long compared with the Lagrangian correlation time. Also, a study is made of the relation between the Lagrangian and the Eulerian correlation function and a hypothesis is advanced and successfully tested. Questions concerning the relation between small eddies and the energy spectrum are considered. A criterion is advanced and successfully tested to decide whether small scale flow can be detected within the large eddies for any given spectrum. A method is developed to determine whether this small scale motion is in any sense periodic. Finally, the relation between two particle dispersion and the energy spectrum is studied anew and various theories are tested
International Nuclear Information System (INIS)
Katsaounis, T D
2005-01-01
The scope of this book is to present well known simple and advanced numerical methods for solving partial differential equations (PDEs) and how to implement these methods using the programming environment of the software package Diffpack. A basic background in PDEs and numerical methods is required by the potential reader. Further, a basic knowledge of the finite element method and its implementation in one and two space dimensions is required. The authors claim that no prior knowledge of the package Diffpack is required, which is true, but the reader should be at least familiar with an object oriented programming language like C++ in order to better comprehend the programming environment of Diffpack. Certainly, a prior knowledge or usage of Diffpack would be a great advantage to the reader. The book consists of 15 chapters, each one written by one or more authors. Each chapter is basically divided into two parts: the first part is about mathematical models described by PDEs and numerical methods to solve these models and the second part describes how to implement the numerical methods using the programming environment of Diffpack. Each chapter closes with a list of references on its subject. The first nine chapters cover well known numerical methods for solving the basic types of PDEs. Further, programming techniques on the serial as well as on the parallel implementation of numerical methods are also included in these chapters. The last five chapters are dedicated to applications, modelled by PDEs, in a variety of fields. In summary, the book focuses on the computational and implementational issues involved in solving partial differential equations. The potential reader should have a basic knowledge of PDEs and the finite difference and finite element methods. The examples presented are solved within the programming framework of Diffpack and the reader should have prior experience with the particular software in order to take full advantage of the book. Overall
Numerical simulations of thrombosis
Directory of Open Access Journals (Sweden)
Naveen Kumar G Ramunigari
2013-01-01
Full Text Available Background: Mathematical approaches for biological events have gained significant importance in development of biomedical research. Deep vein thrombosis (DVT is caused by blood clot in veins deeply rooted in the body, resulting in loss of blood, pain, and numbness of the body part associated with that vein. This situation can get complicated and can be fatal, when the blood clot travels to other parts of the body which may result in pulmonary embolism (PE. PE causes approximately 300,000 deaths annually in the United States alone. Materials and Methods: We are trying to propose a computational approach for understanding venous thrombosis using the theory of fluid mechanics. In our study, we are trying to establish a computational model that mimics the venous blood flow containing unidirectional venous valves and will be depicting the blood flow in the veins. We analyzed the flow patterns in veins, which are included with lump like substances. This lump like substances can be clots, tissue debris, collagen or even cholesterol. Our study will facilitate better understanding of the biophysical process in case of thrombosis. Results: The predicted model analyzes the consequences that occur due to the clot formations in veins. Knowledge of Navier-Stokes equations in fluid dynamics along with the computational model of a complex biological system would help in diagnosis of the problem at much faster rate of time. Valves of the deep veins are damaged as a result of DVT, with no valves to prevent deep system reflux, the hydrostatic venous pressure in the lower extremity increases dramatically. Conclusion: Our model is used to determine the effects of an interrupted blood flow as a result of thrombin formation, which might result in disturbed systemic circulation. Our results indicated a positive inverse correlation exists between clots and the flow velocity. This would support medical practitioners to recommend faster curing measures.
Space Environments and Spacecraft Effects Organization Concept
Edwards, David L.; Burns, Howard D.; Miller, Sharon K.; Porter, Ron; Schneider, Todd A.; Spann, James F.; Xapsos, Michael
2012-01-01
The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while also expanding its mission to explore the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. Each new destination presents an opportunity to increase our knowledge of the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments disciplines that will help serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environments and spacecraft effects (SENSE) organization. This SENSE organization includes disciplines such as space climate, space weather, natural and induced space environments, effects on spacecraft materials and systems and the transition of research information into application. This space environment and spacecraft effects organization will be composed of Technical Working Groups (TWG). These technical working groups will survey customers and users, generate products, and provide knowledge supporting four functional areas: design environments, engineering effects, operational support, and programmatic support. The four functional areas align with phases in the program mission lifecycle and are briefly described below. Design environments are used primarily in the mission concept and design phases of a program. Engineering effects focuses on the material, component, sub-system and system-level selection and the testing to verify design and operational performance. Operational support provides products based on real time or near real time space weather to mission operators to aid in real time and near-term decision-making. The programmatic support function maintains an interface with the numerous programs within NASA, other federal
Motorcycle noise in a park environment
2013-06-01
The Blue Ridge Parkway National Park provided an environment where sound level : measurements could be made for numerous motorcycle pass-by events. Data were examined : for five motorcycle categories: cruiser, sport, dual purpose, touring, and : mope...
Transportation package design using numerical optimization
International Nuclear Information System (INIS)
Harding, D.C.; Witkowski, W.R.
1993-01-01
Since the design of transportation packages involves a complex coupling of structural, thermal and radiation shielding analyses and must follow very strict design constraints, numerical optimization provides the potential for more efficient container designs. In numerical optimization, the requirements of the design problem are mathematically formulated through the use of an objective function and constraints. The objective function(s), e.g., package weight, cost, volume, or combination thereof, is the function to be minimized or maximized by altering a set of design variables that define the package's shape and dimensions. Constraints are limitations on the performance of the system, such as resisting structural and thermal accident environments. Two constraints defined for an example wire mesh composite Type B package are: 1) deformation in the containment vessel seal region remains small enough throughout the 10 CFR-71 accident conditions to meet containment criteria, and 2) the elastomeric seal region remains below its operational temperature limit to guarantee seal integrity in the fire environment. The first constraint of a minimum energy absorbing layer thickness is evaluated with finite element analyses of the proposed dynamic crush accident criteria. The second constraint is evaluated with a 1-D transient thermal finite difference code parametrized for variable composite layer thicknesses, and is integrated with the optimization process. (J.P.N.)
Quantum Darwinism for mixed-state environment
Quan, Haitao; Zwolak, Michael; Zurek, Wojciech
2009-03-01
We exam quantum darwinism when a system is in the presence of a mixed environment, and we find a general relation between the mutual information for the mixed-state environment and the change of the entropy of the fraction of the environment. We then look at a particular solvable model, and we numerically exam the time evolution of the ``mutual information" for large environment. Finally we discuss about the exact expressions for all entropies and the mutual information at special time.
Bier, H.H.
2011-01-01
Technological and conceptual advances in fields such as artificial intelligence, robotics, and material science have enabled robotic architectural environments to be implemented and tested in the last decade in virtual and physical prototypes. These prototypes are incorporating sensing-actuating
DEFF Research Database (Denmark)
Thomsen, Bo Stjerne
2008-01-01
The paper explores how performative architecture can act as a collective environment localizing urban flows and establishing public domains through the integration of pervasive computing and animation techniques. The NoRA project introduces the concept of ‘performative environments,' focusing on ...... of local interactions and network behaviour, building becomes social infrastructure and prompts an understanding of architectural structures as quasiobjects, which can retain both variation and recognisability in changing social constellations.......The paper explores how performative architecture can act as a collective environment localizing urban flows and establishing public domains through the integration of pervasive computing and animation techniques. The NoRA project introduces the concept of ‘performative environments,' focusing...
The Numerical FEM Model of the Kinematics of the Vibratory Shot Peening Process
Directory of Open Access Journals (Sweden)
Stanisław Bławucki
2017-12-01
Full Text Available The paper presents the results of numerical calculations, with the finite element method in the ABAQUS program environment, of the vibratory shot peening process with loose peening elements. The behaviour of shot peening elements was analysed in the kinematic aspect. The impact of the initial deployment of vibratory shot peening elements on their behaviour during processing was investigated, including the displacement, velocity, acceleration and the number of collisions. The way of determining the effectiveness of the processing with the vibratory shot peening was illustrated.
Numerical Verification Of Equilibrium Chemistry
International Nuclear Information System (INIS)
Piro, Markus; Lewis, Brent; Thompson, William T.; Simunovic, Srdjan; Besmann, Theodore M.
2010-01-01
A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.
BCJ numerators from reduced Pfaffian
Energy Technology Data Exchange (ETDEWEB)
Du, Yi-Jian [Center for Theoretical Physics, School of Physics and Technology, Wuhan University,No. 299 Bayi Road, Wuhan 430072 (China); Teng, Fei [Department of Physics and Astronomy, University of Utah,115 South 1400 East, Salt Lake City, UT 84112 (United States)
2017-04-07
By expanding the reduced Pfaffian in the tree level Cachazo-He-Yuan (CHY) integrands for Yang-Mills (YM) and nonlinear sigma model (NLSM), we can get the Bern-Carrasco-Johansson (BCJ) numerators in Del Duca-Dixon-Maltoni (DDM) form for arbitrary number of particles in any spacetime dimensions. In this work, we give a set of very straightforward graphic rules based on spanning trees for a direct evaluation of the BCJ numerators for YM and NLSM. Such rules can be derived from the Laplace expansion of the corresponding reduced Pfaffian. For YM, the each one of the (n−2)! DDM form BCJ numerators contains exactly (n−1)! terms, corresponding to the increasing trees with respect to the color order. For NLSM, the number of nonzero numerators is at most (n−2)!−(n−3)!, less than those of several previous constructions.
Integrating indicators in a national accounting matrix including environmental accounts (NAMEA)
International Nuclear Information System (INIS)
De Haan, M.; Keuning, S.J.; Bosch, P.R.
1993-01-01
Five environmental indicators are conceptually and numerically integrated into a National Accounting Matrix including Environmental Accounts (NAMEA) for 1989. As a consequence, these estimates are directly comparable with outcomes of major macro-economic aggregates in the conventional accounts. In the NAMEA, emissions of all kinds of polluting agents are recorded by industry and by consumption purpose. Subsequently, these agents are grouped into five environmental themes: greenhouse effect, ozone layer depletion, acidification, eutrophication and waste accumulation. The contributions of agents to certain themes are expressed in theme-related environmental stress equivalents. Per theme, these stress equivalents are confronted with policy norms set by the Netherlands government for the year 2000. This results in a statistical framework at a meso-level from which integrated economic and environmental indicators are derived. The NAMEA may also serve as a data base and analytical device for modelling interactions between the national economy and changes in the environment. 13 tabs., 2 app., 32 refs
Numerical Analysis of Multiscale Computations
Engquist, Björn; Tsai, Yen-Hsi R
2012-01-01
This book is a snapshot of current research in multiscale modeling, computations and applications. It covers fundamental mathematical theory, numerical algorithms as well as practical computational advice for analysing single and multiphysics models containing a variety of scales in time and space. Complex fluids, porous media flow and oscillatory dynamical systems are treated in some extra depth, as well as tools like analytical and numerical homogenization, and fast multipole method.
Czech Academy of Sciences Publication Activity Database
Drnovšek, R.; Müller, Vladimír
2014-01-01
Roč. 62, č. 9 (2014), s. 1197-1204 ISSN 0308-1087 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : joint numerical range * numerical radius Subject RIV: BA - General Mathematics Impact factor: 0.738, year: 2014 http://www.tandfonline.com/doi/abs/10.1080/03081087.2013.816303
A novel numerical model for estimating the collapse pressure of flexible pipes
Energy Technology Data Exchange (ETDEWEB)
Nogueira, Victor P.P.; Antoun Netto, Theodoro [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao em Engenharia], e-mail: victor@lts.coppe.ufrj.br
2009-07-01
As the worldwide oil and gas industry operational environments move to ultra-deep waters, failure mechanisms in flexible pipes such as instability of the armor layers under compression and hydrostatic collapse are more likely to occur. Therefore, it is important to develop reliable numerical tools to reproduce the failure mechanisms that may occur in flexible pipes. This work presents a representative finite element model of flexible pipe capable to reproduce its pre and post-collapse behavior under hydrostatic pressure. The model, developed in the scope of this work, uses beam elements and includes nonlinear kinematics and material behavior influences. The dependability of the numerical results is assessed in light of experimental tests on flexible pipes with 4 inches and 8 inches nominal diameter available in the literature (Souza, 2002). The applied methodology provided coherent values regarding the estimation of the collapse pressures and results have shown that the proposed model is capable to reproduce experimental results. (author)
On the numerical verification of industrial codes
International Nuclear Information System (INIS)
Montan, Sethy Akpemado
2013-01-01
Numerical verification of industrial codes, such as those developed at EDF R and D, is required to estimate the precision and the quality of computed results, even more for code running in HPC environments where millions of instructions are performed each second. These programs usually use external libraries (MPI, BLACS, BLAS, LAPACK). In this context, it is required to have a tool as non intrusive as possible to avoid rewriting the original code. In this regard, the CADNA library, which implements the Discrete Stochastic Arithmetic, appears to be one of a promising approach for industrial applications. In the first part of this work, we are interested in an efficient implementation of the BLAS routine DGEMM (General Matrix Multiply) implementing Discrete Stochastic Arithmetic. The implementation of a basic algorithm for matrix product using stochastic types leads to an overhead greater than 1000 for a matrix of 1024 * 1024 compared to the standard version and commercial versions of xGEMM. Here, we detail different solutions to reduce this overhead and the results we have obtained. A new routine Dgemm- CADNA have been designed. This routine has allowed to reduce the overhead from 1100 to 35 compare to optimized BLAS implementations (GotoBLAS). Then, we focus on the numerical verification of Telemac-2D computed results. Performing a numerical validation with the CADNA library shows that more than 30% of the numerical instabilities occurring during an execution come from the dot product function. A more accurate implementation of the dot product with compensated algorithms is presented in this work. We show that implementing these kinds of algorithms, in order to improve the accuracy of computed results does not alter the code performance. (author)
Numerical study of effect of oxygen fraction on local entropy ...
Indian Academy of Sciences (India)
This study considers numerical simulation of the combustion of methane with air, including oxygen and nitrogen, in a burner and the numerical solution of local entropy generation rate due to high temperature and velocity gradients in the combustion chamber. The effects of equivalence ratio () and oxygen percentage () ...
Magnitude Knowledge: The Common Core of Numerical Development
Siegler, Robert S.
2016-01-01
The integrated theory of numerical development posits that a central theme of numerical development from infancy to adulthood is progressive broadening of the types and ranges of numbers whose magnitudes are accurately represented. The process includes four overlapping trends: (1) representing increasingly precisely the magnitudes of non-symbolic…
Hybrid numerical calculation method for bend waveguides
Garnier , Lucas; Saavedra , C.; Castro-Beltran , Rigoberto; Lucio , José Luis; Bêche , Bruno
2017-01-01
National audience; The knowledge of how the light will behave in a waveguide with a radius of curvature becomes more and more important because of the development of integrated photonics, which include ring micro-resonators, phasars, and other devices with a radius of curvature. This work presents a numerical calculation method to determine the eigenvalues and eigenvectors of curved waveguides. This method is a hybrid method which uses at first conform transformation of the complex plane gene...
Numerical Simulation Of Silicon-Ribbon Growth
Woda, Ben K.; Kuo, Chin-Po; Utku, Senol; Ray, Sujit Kumar
1987-01-01
Mathematical model includes nonlinear effects. In development simulates growth of silicon ribbon from melt. Takes account of entire temperature and stress history of ribbon. Numerical simulations performed with new model helps in search for temperature distribution, pulling speed, and other conditions favoring growth of wide, flat, relatively defect-free silicon ribbons for solar photovoltaic cells at economically attractive, high production rates. Also applicable to materials other than silicon.
Magay, A. A.; Bulgakova, E. A.; Zabelina, S. A.
2018-03-01
The article highlights issues surrounding development of high rise buildings. With the rapid increase of the global population there has been a trend for people to migrate into megacities and has caused the expansion of big city territories. This trend, coupled with the desire for a comfortable living environment, has resulted in numerous problems plaguing the megacity. This article proposes that a viable solution to the problems facing megacities is to create vertical layout environments. Potential options for creating vertical layout environments are set out below including the construction of buildings with atriums. Further, the article puts forth suggested spatial organization of the environment as well as optimal landscaping of high-rise buildings and constructions for the creation of vertical layout environments. Finally, the persuasive reasons for the adoption of vertical layout environments is that it will decrease the amount of developed urban areas, decrease traffic and increase environmental sustainability.
Numerical simulations of progressive hardening by using ABAQUS FEA software
Directory of Open Access Journals (Sweden)
Domański Tomasz
2018-01-01
Full Text Available The paper concerns numerical simulations of progressive hardening include phase transformations in solid state of steel. Abaqus FEA software is used for numerical analysis of temperature field and phase transformations. Numerical subroutines, written in fortran programming language are used in computer simulations where models of the distribution of movable heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Model for evaluation of fractions of phases and their kinetics is based on continuous heating diagram and continuous cooling diagram. The numerical analysis of thermal fields, phase fractions and strain associated progressive hardening of elements made of steel were done.
Classical mechanics including an introduction to the theory of elasticity
Hentschke, Reinhard
2017-01-01
This textbook teaches classical mechanics as one of the foundations of physics. It describes the mechanical stability and motion in physical systems ranging from the molecular to the galactic scale. Aside from the standard topics of mechanics in the physics curriculum, this book includes an introduction to the theory of elasticity and its use in selected modern engineering applications, e.g. dynamic mechanical analysis of viscoelastic materials. The text also covers many aspects of numerical mechanics, ranging from the solution of ordinary differential equations, including molecular dynamics simulation of many particle systems, to the finite element method. Attendant Mathematica programs or parts thereof are provided in conjunction with selected examples. Numerous links allow the reader to connect to related subjects and research topics. Among others this includes statistical mechanics (separate chapter), quantum mechanics, space flight, galactic dynamics, friction, and vibration spectroscopy. An introductory...
SEEPAGE MODEL FOR PA INCLUDING DRIFT COLLAPSE
International Nuclear Information System (INIS)
C. Tsang
2004-01-01
The purpose of this report is to document the predictions and analyses performed using the seepage model for performance assessment (SMPA) for both the Topopah Spring middle nonlithophysal (Tptpmn) and lower lithophysal (Tptpll) lithostratigraphic units at Yucca Mountain, Nevada. Look-up tables of seepage flow rates into a drift (and their uncertainty) are generated by performing numerical simulations with the seepage model for many combinations of the three most important seepage-relevant parameters: the fracture permeability, the capillary-strength parameter 1/a, and the percolation flux. The percolation flux values chosen take into account flow focusing effects, which are evaluated based on a flow-focusing model. Moreover, multiple realizations of the underlying stochastic permeability field are conducted. Selected sensitivity studies are performed, including the effects of an alternative drift geometry representing a partially collapsed drift from an independent drift-degradation analysis (BSC 2004 [DIRS 166107]). The intended purpose of the seepage model is to provide results of drift-scale seepage rates under a series of parameters and scenarios in support of the Total System Performance Assessment for License Application (TSPA-LA). The SMPA is intended for the evaluation of drift-scale seepage rates under the full range of parameter values for three parameters found to be key (fracture permeability, the van Genuchten 1/a parameter, and percolation flux) and drift degradation shape scenarios in support of the TSPA-LA during the period of compliance for postclosure performance [Technical Work Plan for: Performance Assessment Unsaturated Zone (BSC 2002 [DIRS 160819], Section I-4-2-1)]. The flow-focusing model in the Topopah Spring welded (TSw) unit is intended to provide an estimate of flow focusing factors (FFFs) that (1) bridge the gap between the mountain-scale and drift-scale models, and (2) account for variability in local percolation flux due to
Lukes, George E.; Cain, Joel M.
1996-02-01
The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.
Towards high fidelity numerical wave tanks for modelling coastal and ocean engineering processes
Cozzuto, G.; Dimakopoulos, A.; de Lataillade, T.; Kees, C. E.
2017-12-01
With the increasing availability of computational resources, the engineering and research community is gradually moving towards using high fidelity Comutational Fluid Mechanics (CFD) models to perform numerical tests for improving the understanding of physical processes pertaining to wave propapagation and interaction with the coastal environment and morphology, either physical or man-made. It is therefore important to be able to reproduce in these models the conditions that drive these processes. So far, in CFD models the norm is to use regular (linear or nonlinear) waves for performing numerical tests, however, only random waves exist in nature. In this work, we will initially present the verification and validation of numerical wave tanks based on Proteus, an open-soruce computational toolkit based on finite element analysis, with respect to the generation, propagation and absorption of random sea states comprising of long non-repeating wave sequences. Statistical and spectral processing of results demonstrate that the methodologies employed (including relaxation zone methods and moving wave paddles) are capable of producing results of similar quality to the wave tanks used in laboratories (Figure 1). Subsequently cases studies of modelling complex process relevant to coastal defences and floating structures such as sliding and overturning of composite breakwaters, heave and roll response of floating caissons are presented. Figure 1: Wave spectra in the numerical wave tank (coloured symbols), compared against the JONSWAP distribution
DEFF Research Database (Denmark)
Lippert, Ingmar
2013-01-01
Enacting Environments is an ethnography of the midst of the encounter between corporations, sustainable development and climate change. At this intersection 'environmental management' and 'carbon accounting' are put into practice. Purportedly, these practices green capitalism. Drawing on fieldwork...... of day-to-day practices of corporate environmental accountants and managers, Ingmar Lippert reconstructs their work as achieving to produce a reality of environment that is simultaneously stable and flexible enough for a particular corporate project: to stage the company, and in consequence capitalism......, as in control over its relations to an antecedent environment. Not confined to mere texts or meetings between shiny stakeholders co-governing the corporation – among them some of the world's biggest auditing firms, an environmental non-governmental organisation (NGO) and standards – control is found...
Introduction to Numerical Computation - analysis and Matlab illustrations
DEFF Research Database (Denmark)
Elden, Lars; Wittmeyer-Koch, Linde; Nielsen, Hans Bruun
In a modern programming environment like eg MATLAB it is possible by simple commands to perform advanced calculations on a personal computer. In order to use such a powerful tool efiiciently it is necessary to have an overview of available numerical methods and algorithms and to know about...... are illustrated by examples in MATLAB....
Numerical assessment of non-uniform corrosion scenarios of rebar ...
Indian Academy of Sciences (India)
Corrosion of embedded rebars is a classical deterioration mechanism that remains as one of the most significant problems limiting the service life of concrete structures exposed to chloride-laden environments. The primary objective of this study is to propose and verify a numerical framework that can efficiently quantify ...
Directory of Open Access Journals (Sweden)
Ines Giunta
2011-10-01
Full Text Available The purpose of this research is the identification of a paradigm which fixes the basic concepts and the type of logical relationships between them, whereby direct, govern and evaluate choises on new technologies. The contribution is based on the assumption that the complexity of knowledge is correlated with the complexity of the learning environment. From the existence of this correlation will descend a series of consequences that contribute to the definition of a theoretical construct in which the logical categories of learning become the guiding criteria on which to design learning environments and, consequently, also the indicators on by which to evaluate its effectiveness.
DEFF Research Database (Denmark)
Knudsen, Herman; Busck, Ole Gunni; Lind, Jens
2011-01-01
The article explores how employee participation influences the quality of the work environment and workers’ well-being at 11 Danish workplaces from within six different industries. Both direct participation and representative forms of participation at the workplace level were studied. Statistical...... as well as qualitative comparative analyses reveal that work environment quality and high levels of participation go hand in hand. Within a typology of participation models the highest level of participation, including strong elements of collective participation, and also the best work environment...
A review of numerical techniques approaching microstructures of crystalline rocks
Zhang, Yahui; Wong, Louis Ngai Yuen
2018-06-01
The macro-mechanical behavior of crystalline rocks including strength, deformability and failure pattern are dominantly influenced by their grain-scale structures. Numerical technique is commonly used to assist understanding the complicated mechanisms from a microscopic perspective. Each numerical method has its respective strengths and limitations. This review paper elucidates how numerical techniques take geometrical aspects of the grain into consideration. Four categories of numerical methods are examined: particle-based methods, block-based methods, grain-based methods, and node-based methods. Focusing on the grain-scale characters, specific relevant issues including increasing complexity of micro-structure, deformation and breakage of model elements, fracturing and fragmentation process are described in more detail. Therefore, the intrinsic capabilities and limitations of different numerical approaches in terms of accounting for the micro-mechanics of crystalline rocks and their phenomenal mechanical behavior are explicitly presented.
Numerical modelling of suspended radioactive sediment transport in a stream using matlab
International Nuclear Information System (INIS)
Sarpong, Linda
2017-07-01
The use of materials that contain radioactive substances has gained grounds in Ghana due to numerous benefits derived from them. These radioactive materials can be found in the areas of medicine, agriculture and industries such as mining. Though there are strict measures to ensure such material do not find its way into the environment, improper management of the waste poses a threat to the environment. To be able to understand the impact the radioactive material has on the environment, mathematical models play a very relevant role in tracking the level of pollution in any medium. This thesis was concerned with the numerical modelling for the transport of the radioactive solute material that suspends in a stream using Matlab at different velocities as a result of flooding or an accident for research purposes. The modelling was done by using partial differential equations describing relevant physical processes evolution which includes water level, dissolved and suspended substances concentration and velocities. The equation system basis are the mass conservation and momentum laws, state equation and state transport equations. The implicit finite difference scheme was used to evaluate the transport equation, Advection-Dispersion Equation (ADE) with respect to time and space. Solution algorithms for Matlab programming were developed and implemented for generating results for analysis. The results obtained showed that the model was able to simulate accurately the various levels of suspended radioactive sediment concentration changes in the flowing stream longitudinally. (au)
African Journals Online (AJOL)
Environmental Studies and Regional Planning Bulletin African Environment is published in French and English, and for some issues, in Arabic. (only the issue below has been received by AJOL). Vol 10, No 3 (1999). DOWNLOAD FULL TEXT Open Access DOWNLOAD FULL TEXT Subscription or Fee Access. Table of ...
Numerical linear algebra a concise introduction with Matlab and Julia
Bornemann, Folkmar
2018-01-01
This book offers an introduction to the algorithmic-numerical thinking using basic problems of linear algebra. By focusing on linear algebra, it ensures a stronger thematic coherence than is otherwise found in introductory lectures on numerics. The book highlights the usefulness of matrix partitioning compared to a component view, leading not only to a clearer notation and shorter algorithms, but also to significant runtime gains in modern computer architectures. The algorithms and accompanying numerical examples are given in the programming environment MATLAB, and additionally – in an appendix – in the future-oriented, freely accessible programming language Julia. This book is suitable for a two-hour lecture on numerical linear algebra from the second semester of a bachelor's degree in mathematics.
Numerical Modelling Of Pumpkin Balloon Instability
Wakefield, D.
Tensys have been involved in the numerical formfinding and load analysis of architectural stressed membrane structures for 15 years. They have recently broadened this range of activities into the `lighter than air' field with significant involvement in aerostat and heavy-lift hybrid airship design. Since early 2004 they have been investigating pumpkin balloon instability on behalf of the NASA ULDB programme. These studies are undertaken using inTENS, an in-house finite element program suite based upon the Dynamic Relaxation solution method and developed especially for the non-linear analysis and patterning of membrane structures. The paper describes the current state of an investigation that started with a numerical simulation of the lobed cylinder problem first studied by Calladine. The influence of material properties and local geometric deformation on stability is demonstrated. A number of models of complete pumpkin balloons have then been established, including a 64-gore balloon with geometry based upon Julian Nott's Endeavour. This latter clefted dramatically upon initial inflation, a phenomenon that has been reproduced in the numerical model. Ongoing investigations include the introduction of membrane contact modelling into inTENS and correlation studies with the series of large-scale ULDB models currently in preparation.
Propagation of steel corrosion in concrete: Experimental and numerical investigations
DEFF Research Database (Denmark)
Michel, Alexander; Otieno, M.; Stang, Henrik
2016-01-01
This paper focuses on experimental and numerical investigations of the propagation phase of reinforcement corrosion to determine anodic and cathodic Tafel constants and exchange current densities, from corrosion current density and corrosion potential measurements. The experimental program includ...
Numerical methods in multibody dynamics
Eich-Soellner, Edda
1998-01-01
Today computers play an important role in the development of complex mechanical systems, such as cars, railway vehicles or machines. Efficient simulation of these systems is only possible when based on methods that explore the strong link between numerics and computational mechanics. This book gives insight into modern techniques of numerical mathematics in the light of an interesting field of applications: multibody dynamics. The important interaction between modeling and solution techniques is demonstrated by using a simplified multibody model of a truck. Different versions of this mechanical model illustrate all key concepts in static and dynamic analysis as well as in parameter identification. The book focuses in particular on constrained mechanical systems. Their formulation in terms of differential-algebraic equations is the backbone of nearly all chapters. The book is written for students and teachers in numerical analysis and mechanical engineering as well as for engineers in industrial research labor...
Extensible numerical library in JAVA
International Nuclear Information System (INIS)
Aso, T.; Okazawa, H.; Takashimizu, N.
2001-01-01
The authors present the current status of the project for developing the numerical library in JAVA. The authors have presented how object-oriented techniques improve usage and also development of numerical libraries compared with the conventional way at previous conference. The authors need many functions for data analysis which is not provided within JAVA language, for example, good random number generators, special functions and so on. Authors' development strategy is focused on easiness of implementation and adding new features by users themselves not only by developers. In HPC field, there are other focus efforts to develop numerical libraries in JAVA. However, their focus is on the performance of execution, not easiness of extension. Following the strategy, the authors have designed and implemented more classes for random number generators and so on
Numerical models for differential problems
Quarteroni, Alfio
2017-01-01
In this text, we introduce the basic concepts for the numerical modelling of partial differential equations. We consider the classical elliptic, parabolic and hyperbolic linear equations, but also the diffusion, transport, and Navier-Stokes equations, as well as equations representing conservation laws, saddle-point problems and optimal control problems. Furthermore, we provide numerous physical examples which underline such equations. We then analyze numerical solution methods based on finite elements, finite differences, finite volumes, spectral methods and domain decomposition methods, and reduced basis methods. In particular, we discuss the algorithmic and computer implementation aspects and provide a number of easy-to-use programs. The text does not require any previous advanced mathematical knowledge of partial differential equations: the absolutely essential concepts are reported in a preliminary chapter. It is therefore suitable for students of bachelor and master courses in scientific disciplines, an...
Numerical simulation of flood barriers
Srb, Pavel; Petrů, Michal; Kulhavý, Petr
This paper deals with testing and numerical simulating of flood barriers. The Czech Republic has been hit by several very devastating floods in past years. These floods caused several dozens of causalities and property damage reached billions of Euros. The development of flood measures is very important, especially for the reduction the number of casualties and the amount of property damage. The aim of flood control measures is the detention of water outside populated areas and drainage of water from populated areas as soon as possible. For new flood barrier design it is very important to know its behaviour in case of a real flood. During the development of the barrier several standardized tests have to be carried out. Based on the results from these tests numerical simulation was compiled using Abaqus software and some analyses were carried out. Based on these numerical simulations it will be possible to predict the behaviour of barriers and thus improve their design.
The Virtual Environment for Reactor Applications (VERA): Design and architecture
International Nuclear Information System (INIS)
Turner, John A.; Clarno, Kevin; Sieger, Matt; Bartlett, Roscoe; Collins, Benjamin; Pawlowski, Roger; Schmidt, Rodney; Summers, Randall
2016-01-01
VERA, the Virtual Environment for Reactor Applications, is the system of physics capabilities being developed and deployed by the Consortium for Advanced Simulation of Light Water Reactors (CASL). CASL was established for the modeling and simulation of commercial nuclear reactors. VERA consists of integrating and interfacing software together with a suite of physics components adapted and/or refactored to simulate relevant physical phenomena in a coupled manner. VERA also includes the software development environment and computational infrastructure needed for these components to be effectively used. We describe the architecture of VERA from both software and numerical perspectives, along with the goals and constraints that drove major design decisions, and their implications. We explain why VERA is an environment rather than a framework or toolkit, why these distinctions are relevant (particularly for coupled physics applications), and provide an overview of results that demonstrate the use of VERA tools for a variety of challenging applications within the nuclear industry.
The Virtual Environment for Reactor Applications (VERA): Design and architecture
Energy Technology Data Exchange (ETDEWEB)
Turner, John A., E-mail: turnerja@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Clarno, Kevin; Sieger, Matt; Bartlett, Roscoe; Collins, Benjamin [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Pawlowski, Roger; Schmidt, Rodney; Summers, Randall [Sandia National Laboratories, Albuquerque, NM 87185 (United States)
2016-12-01
VERA, the Virtual Environment for Reactor Applications, is the system of physics capabilities being developed and deployed by the Consortium for Advanced Simulation of Light Water Reactors (CASL). CASL was established for the modeling and simulation of commercial nuclear reactors. VERA consists of integrating and interfacing software together with a suite of physics components adapted and/or refactored to simulate relevant physical phenomena in a coupled manner. VERA also includes the software development environment and computational infrastructure needed for these components to be effectively used. We describe the architecture of VERA from both software and numerical perspectives, along with the goals and constraints that drove major design decisions, and their implications. We explain why VERA is an environment rather than a framework or toolkit, why these distinctions are relevant (particularly for coupled physics applications), and provide an overview of results that demonstrate the use of VERA tools for a variety of challenging applications within the nuclear industry.
Graphical programming interface: A development environment for MRI methods.
Zwart, Nicholas R; Pipe, James G
2015-11-01
To introduce a multiplatform, Python language-based, development environment called graphical programming interface for prototyping MRI techniques. The interface allows developers to interact with their scientific algorithm prototypes visually in an event-driven environment making tasks such as parameterization, algorithm testing, data manipulation, and visualization an integrated part of the work-flow. Algorithm developers extend the built-in functionality through simple code interfaces designed to facilitate rapid implementation. This article shows several examples of algorithms developed in graphical programming interface including the non-Cartesian MR reconstruction algorithms for PROPELLER and spiral as well as spin simulation and trajectory visualization of a FLORET example. The graphical programming interface framework is shown to be a versatile prototyping environment for developing numeric algorithms used in the latest MR techniques. © 2014 Wiley Periodicals, Inc.
Numeral Incorporation in Japanese Sign Language
Ktejik, Mish
2013-01-01
This article explores the morphological process of numeral incorporation in Japanese Sign Language. Numeral incorporation is defined and the available research on numeral incorporation in signed language is discussed. The numeral signs in Japanese Sign Language are then introduced and followed by an explanation of the numeral morphemes which are…
Developments in numerical simulation of IFE target and chamber physics
International Nuclear Information System (INIS)
Velarde, G.; Minguez, E.; Alonso, E.; Gil, J.M.; Malerba, L.; Marian, J.; Martel, P.; Martinez-Val, J.M.; Munoz, R.; Ogando, F.; Perlado, J.M.; Piera, M.; Reyes, S.; Rubiano, J.G.; Sanz, J.; Sauvan, P.; Velarde, M.; Velarde, P.
2000-01-01
The work presented outlines the global frame given at the Institute of Nuclear Fusion (DENIM) for having an integral perspective of the different research areas with the development of Inertial Fusion for energy generation. The coupling of a new radiation transport (RT) solver with an existing multi-material fluid dynamics code using Adaptive Mesh Refinement (ARM) is presented in Section 2, including improvements and additional information about the solver precision. In Section 3, new developments in the atomic physics codes under target conditions, to determine populations, opacity data and emissivities have been performed. Exotic and innovative ideas about Inertial Fusion Energy (IFE), as catalytic fuels and Z-pinches have been explored, and they are explained in Section 4. Numerical simulations demonstrate important reductions in the tritium inventory. Section 5 is devoted to safety and environment of the IFE. Uncertainties analysis in activation calculations have been included in the ACAB activation code, and also calculations on pulse activation in IFE reactors and on the activation of target debris in NIF are presented. A comparison of the accidental releases of tritium from some IFE reactors computed using MACCS2 code is explained. Finally, Section 6 contains the research on the basic mechanisms of neutron damage in SiC (low-activation material) and FeCu alloy using the DENIM/LLNL molecular dynamics code MDCASK. (authors)
Blast mitigation experimental and numerical studies
2013-01-01
Presents experimental methods of material and structural response to dynamic blast loads Includes computational analysis of material and structural response to dynamic blast loads Offers mitigation measures for structures in various environments Relates lab experiments to larger field tests Features more than 150 illustrations
Numerical precision control and GRACE
International Nuclear Information System (INIS)
Fujimoto, J.; Hamaguchi, N.; Ishikawa, T.; Kaneko, T.; Morita, H.; Perret-Gallix, D.; Tokura, A.; Shimizu, Y.
2006-01-01
The control of the numerical precision of large-scale computations like those generated by the GRACE system for automatic Feynman diagram calculations has become an intrinsic part of those packages. Recently, Hitachi Ltd. has developed in FORTRAN a new library HMLIB for quadruple and octuple precision arithmetic where the number of lost-bits is made available. This library has been tested with success on the 1-loop radiative correction to e + e - ->e + e - τ + τ - . It is shown that the approach followed by HMLIB provides an efficient way to track down the source of numerical significance losses and to deliver high-precision results yet minimizing computing time
Numeric invariants from multidimensional persistence
Energy Technology Data Exchange (ETDEWEB)
Skryzalin, Jacek [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carlsson, Gunnar [Stanford Univ., Stanford, CA (United States)
2017-05-19
In this paper, we analyze the space of multidimensional persistence modules from the perspectives of algebraic geometry. We first build a moduli space of a certain subclass of easily analyzed multidimensional persistence modules, which we construct specifically to capture much of the information which can be gained by using multidimensional persistence over one-dimensional persistence. We argue that the global sections of this space provide interesting numeric invariants when evaluated against our subclass of multidimensional persistence modules. Lastly, we extend these global sections to the space of all multidimensional persistence modules and discuss how the resulting numeric invariants might be used to study data.
Experimental and numerical investigations of plasma turbulence
International Nuclear Information System (INIS)
Huld, T.
1990-07-01
Turbulence in plasmas has been investigated experimentally and numerically. The work described here is divided into four parts: - experiments on edge turbulence in a single-ended Q-machine. Convective cells are investigated in detail together with the anomalous transport caused by them. - Numerical simulation of the edge turbulence in the Q-machine. This simulation uses spectral methods to solve Euler's equation in a cylindrical geometry. - Measurements on wave propagation and the ion beam instability in an unmagnetized plasma with an ion beam with a finite diameter. - Development of software for the automated acquisition of data. This program can control an experiment as well as make measurements. It also include a graphics part. (author) 66 ills., 47 refs
40 CFR 1508.14 - Human environment.
2010-07-01
... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Human environment. 1508.14 Section 1508.14 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY TERMINOLOGY AND INDEX § 1508.14 Human environment. Human environment shall be interpreted comprehensively to include the natural and...
Numerical modeling of economic uncertainty
DEFF Research Database (Denmark)
Schjær-Jacobsen, Hans
2007-01-01
Representation and modeling of economic uncertainty is addressed by different modeling methods, namely stochastic variables and probabilities, interval analysis, and fuzzy numbers, in particular triple estimates. Focusing on discounted cash flow analysis numerical results are presented, comparisons...... are made between alternative modeling methods, and characteristics of the methods are discussed....
Numerical relativity and asymptotic flatness
International Nuclear Information System (INIS)
Deadman, E; Stewart, J M
2009-01-01
It is highly plausible that the region of spacetime far from an isolated gravitating body is, in some sense, asymptotically Minkowskian. However theoretical studies of the full nonlinear theory, initiated by Bondi et al (1962 Proc. R. Soc. A 269 21-51), Sachs (1962 Proc. R. Soc. A 270 103-26) and Newman and Unti (1962 J. Math. Phys. 3 891-901), rely on careful, clever, a priori choices of a chart (and tetrad) and so are not readily accessible to the numerical relativist, who chooses her/his chart on the basis of quite different grounds. This paper seeks to close this gap. Starting from data available in a typical numerical evolution, we construct a chart and tetrad which are, asymptotically, sufficiently close to the theoretical ones, so that the key concepts of the Bondi news function, Bondi mass and its rate of decrease can be estimated. In particular, these estimates can be expressed in the numerical relativist's chart as numerical relativity recipes.
Numerical solution of Boltzmann's equation
International Nuclear Information System (INIS)
Sod, G.A.
1976-04-01
The numerical solution of Boltzmann's equation is considered for a gas model consisting of rigid spheres by means of Hilbert's expansion. If only the first two terms of the expansion are retained, Boltzmann's equation reduces to the Boltzmann-Hilbert integral equation. Successive terms in the Hilbert expansion are obtained by solving the same integral equation with a different source term. The Boltzmann-Hilbert integral equation is solved by a new very fast numerical method. The success of the method rests upon the simultaneous use of four judiciously chosen expansions; Hilbert's expansion for the distribution function, another expansion of the distribution function in terms of Hermite polynomials, the expansion of the kernel in terms of the eigenvalues and eigenfunctions of the Hilbert operator, and an expansion involved in solving a system of linear equations through a singular value decomposition. The numerical method is applied to the study of the shock structure in one space dimension. Numerical results are presented for Mach numbers of 1.1 and 1.6. 94 refs, 7 tables, 1 fig
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)
Gaps in nonsymmetric numerical semigroups
International Nuclear Information System (INIS)
Fel, Leonid G.; Aicardi, Francesca
2006-12-01
There exist two different types of gaps in the nonsymmetric numerical semigroups S(d 1 , . . . , d m ) finitely generated by a minimal set of positive integers {d 1 , . . . , d m }. We give the generating functions for the corresponding sets of gaps. Detailed description of both gap types is given for the 1st nontrivial case m = 3. (author)
Numerical simulation in plasma physics
International Nuclear Information System (INIS)
Samarskii, A.A.
1980-01-01
Plasma physics is not only a field for development of physical theories and mathematical models but also an object of application of the computational experiment comprising analytical and numerical methods adapted for computers. The author considers only MHD plasma physics problems. Examples treated are dissipative structures in plasma; MHD model of solar dynamo; supernova explosion simulation; and plasma compression by a liner. (Auth.)
Numerical computation of MHD equilibria
International Nuclear Information System (INIS)
Atanasiu, C.V.
1982-10-01
A numerical code for a two-dimensional MHD equilibrium computation has been carried out. The code solves the Grad-Shafranov equation in its integral form, for both formulations: the free-boundary problem and the fixed boundary one. Examples of the application of the code to tokamak design are given. (author)
International Nuclear Information System (INIS)
Douglas, Michael R.; Karp, Robert L.; Lukic, Sergio; Reinbacher, Rene
2008-01-01
We develop numerical methods for approximating Ricci flat metrics on Calabi-Yau hypersurfaces in projective spaces. Our approach is based on finding balanced metrics and builds on recent theoretical work by Donaldson. We illustrate our methods in detail for a one parameter family of quintics. We also suggest several ways to extend our results
Numerical modeling of slow shocks
International Nuclear Information System (INIS)
Winske, D.
1987-01-01
This paper reviews previous attempt and the present status of efforts to understand the structure of slow shocks by means of time dependent numerical calculations. Studies carried out using MHD or hybrid-kinetic codes have demonstrated qualitative agreement with theory. A number of unresolved issues related to hybrid simulations of the internal shock structure are discussed in some detail. 43 refs., 8 figs
Directory of Open Access Journals (Sweden)
Knyazheva Yu. V.
2014-06-01
Full Text Available The market economy causes need of development of the economic analysis first of all at microlevel, that is at the level of the separate enterprises as the enterprises are basis for market economy. Therefore improvement of the queuing system trading enterprise is an important economic problem. Analytical solutions of problems of the mass servicing are in described the theory, don’t correspond to real operating conditions of the queuing systems. Therefore in this article optimization of customer service process and improvement of settlement and cash service system trading enterprise are made by means of numerical statistical simulation of the queuing system trading enterprise. The article describe integrated statistical numerical simulation model of queuing systems trading enterprise working in nonstationary conditions with reference to different distribution laws of customers input stream. This model takes account of various behavior customers output stream, includes checkout service model which takes account of cashier rate of working, also this model includes staff motivation model, profit earning and profit optimization models that take into account possible revenue and costs. The created statistical numerical simulation model of queuing systems trading enterprise, at its realization in the suitable software environment, allows to perform optimization of the most important parameters of system. And when developing the convenient user interface, this model can be a component of support decision-making system for rationalization of organizational structure and for management optimization by trading enterprise.
RELAP-7 Numerical Stabilization: Entropy Viscosity Method
Energy Technology Data Exchange (ETDEWEB)
R. A. Berry; M. O. Delchini; J. Ragusa
2014-06-01
The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.
Including environmental concerns in energy policies
International Nuclear Information System (INIS)
Potier, Michel
2014-05-01
In this article, the author comments the different impacts on the environment and risks related to energy, provided that all energies have an impact on the environment (renewable energies are generally cleaner than fossil energies) and these impacts can be on human health, ecosystems, buildings, crops, landscapes, and climate change. He comments the efforts made in the search for a higher energetic efficiency, and proposes an overview of the various available tools implemented by environmental policies in the energy sector: regulatory instruments, economic instruments, negotiated agreements, and informational instruments. He comments the implementation of an energetic taxing aimed at developing a greater respect of the environment
Radiation effects in the environment
Energy Technology Data Exchange (ETDEWEB)
Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy
1999-04-01
Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.
International Nuclear Information System (INIS)
Garrett, H.B.
1998-01-01
Coupled with the increasing concern over trapped radiation effects on microelectronics, the availability of new data, long term changes in the Earth's magnetic field, and observed variations in the trapped radiation fluxes have generated the need for better, more comprehensive tools for modeling and predicting the Earth's trapped radiation environment and its effects on space systems. The objective of this report is to describe the current status of those efforts and review methods for attacking the issues associated with modeling the trapped radiation environment in a systematic, practical fashion. The ultimate goal will be to point the way to increasingly better methods of testing, designing, and flying reliable microelectronic systems in the Earth's radiation environment. The review will include a description of the principal models of the trapped radiation environment currently available--the AE8 and AP8 models. Recent results rom radiation experiments on spacecraft such as CRRES, SAMPEX, and CLEMENTINE will then be described. (author)
Built environment and diabetes
Pasala, Sudhir Kumar; Rao, Allam Appa; Sridhar, G. R.
2010-01-01
Development of type 2 diabetes mellitus is influenced by built environment, which is, ‘the environments that are modified by humans, including homes, schools, workplaces, highways, urban sprawls, accessibility to amenities, leisure, and pollution.’ Built environment contributes to diabetes through access to physical activity and through stress, by affecting the sleep cycle. With globalization, there is a possibility that western environmental models may be replicated in developing countries such as India, where the underlying genetic predisposition makes them particularly susceptible to diabetes. Here we review published information on the relationship between built environment and diabetes, so that appropriate modifications can be incorporated to reduce the risk of developing diabetes mellitus. PMID:20535308
Analysis of Smart Composite Structures Including Debonding
Chattopadhyay, Aditi; Seeley, Charles E.
1997-01-01
Smart composite structures with distributed sensors and actuators have the capability to actively respond to a changing environment while offering significant weight savings and additional passive controllability through ply tailoring. Piezoelectric sensing and actuation of composite laminates is the most promising concept due to the static and dynamic control capabilities. Essential to the implementation of these smart composites are the development of accurate and efficient modeling techniques and experimental validation. This research addresses each of these important topics. A refined higher order theory is developed to model composite structures with surface bonded or embedded piezoelectric transducers. These transducers are used as both sensors and actuators for closed loop control. The theory accurately captures the transverse shear deformation through the thickness of the smart composite laminate while satisfying stress free boundary conditions on the free surfaces. The theory is extended to include the effect of debonding at the actuator-laminate interface. The developed analytical model is implemented using the finite element method utilizing an induced strain approach for computational efficiency. This allows general laminate geometries and boundary conditions to be analyzed. The state space control equations are developed to allow flexibility in the design of the control system. Circuit concepts are also discussed. Static and dynamic results of smart composite structures, obtained using the higher order theory, are correlated with available analytical data. Comparisons, including debonded laminates, are also made with a general purpose finite element code and available experimental data. Overall, very good agreement is observed. Convergence of the finite element implementation of the higher order theory is shown with exact solutions. Additional results demonstrate the utility of the developed theory to study piezoelectric actuation of composite
Benavides-Varela, Silvia; Butterworth, Brian; Burgio, Francesca; Arcara, Giorgio; Lucangeli, Daniela; Semenza, Carlo
2016-01-01
It is currently accepted that certain activities within the family environment contribute to develop early numerical skills before schooling. However, it is unknown whether this early experience influences both the exact and the approximate representation of numbers, and if so, which is more important for numerical tasks. In the present study the mathematical performance of 110 children (mean age 5 years 11 months) was evaluated using a battery that included tests of approximate and exact numerical abilities, as well as everyday numerical problems. Moreover, children were assessed on their knowledge of number information learned at home. The parents of the participants provided information regarding daily activities of the children and socio-demographic characteristics of the family. The results showed that the amount of numerical information learned at home was a significant predictor of participants' performance on everyday numerical problems and exact number representations, even after taking account of age, memory span and socio-economic and educational status of the family. We also found that particular activities, such as board games, correlate with the children's counting skills, which are foundational for arithmetic. Crucially, tests relying on approximate representations were not predicted by the numerical knowledge acquired at home. The present research supports claims about the importance and nature of home experiences in the child's acquisition of mathematics. PMID:26903902
Designing an adaptive salutogenic care environment
Dalton, Cathy; Harrison, Jim D.
2011-01-01
Humans are profoundly affected by the surroundings which they inhabit. Environmental psychologists have produced numerous credible theories describing optimal human environments, based on the concept of congruence or “fit” (1, 2). Lack of person/environment fit can lead to stress-related illness and lack of psychosocial well-being (3). Conversely, appropriately designed environments can promote wellness (4) or “salutogenesis” (5). Increasingly, research in the area of Evidence-Based Design, l...
INTERNAL ENVIRONMENT ANALYSIS TECHNIQUES
Directory of Open Access Journals (Sweden)
Caescu Stefan Claudiu
2011-12-01
Full Text Available Theme The situation analysis, as a separate component of the strategic planning, involves collecting and analysing relevant types of information on the components of the marketing environment and their evolution on the one hand and also on the organization’s resources and capabilities on the other. Objectives of the Research The main purpose of the study of the analysis techniques of the internal environment is to provide insight on those aspects that are of strategic importance to the organization. Literature Review The marketing environment consists of two distinct components, the internal environment that is made from specific variables within the organization and the external environment that is made from variables external to the organization. Although analysing the external environment is essential for corporate success, it is not enough unless it is backed by a detailed analysis of the internal environment of the organization. The internal environment includes all elements that are endogenous to the organization, which are influenced to a great extent and totally controlled by it. The study of the internal environment must answer all resource related questions, solve all resource management issues and represents the first step in drawing up the marketing strategy. Research Methodology The present paper accomplished a documentary study of the main techniques used for the analysis of the internal environment. Results The special literature emphasizes that the differences in performance from one organization to another is primarily dependant not on the differences between the fields of activity, but especially on the differences between the resources and capabilities and the ways these are capitalized on. The main methods of analysing the internal environment addressed in this paper are: the analysis of the organizational resources, the performance analysis, the value chain analysis and the functional analysis. Implications Basically such
Numerical modeling of fires on gas pipelines
International Nuclear Information System (INIS)
Zhao Yang; Jianbo Lai; Lu Liu
2011-01-01
When natural gas is released through a hole on a high-pressure pipeline, it disperses in the atmosphere as a jet. A jet fire will occur when the leaked gas meets an ignition source. To estimate the dangerous area, the shape and size of the fire must be known. The evolution of the jet fire in air is predicted by using a finite-volume procedure to solve the flow equations. The model is three-dimensional, elliptic and calculated by using a compressibility corrected version of the k - ξ turbulence model, and also includes a probability density function/laminar flamelet model of turbulent non-premixed combustion process. Radiation heat transfer is described using an adaptive version of the discrete transfer method. The model is compared with the experiments about a horizontal jet fire in a wind tunnel in the literature with success. The influence of wind and jet velocity on the fire shape has been investigated. And a correlation based on numerical results for predicting the stoichiometric flame length is proposed. - Research highlights: → We developed a model to predict the evolution of turbulent jet diffusion flames. → Measurements of temperature distributions match well with the numerical predictions. → A correlation has been proposed to predict the stoichiometric flame length. → Buoyancy effects are higher in the numerical results. → The radiative heat loss is bigger in the experimental results.
Numerical abilities in fish: A methodological review.
Agrillo, Christian; Miletto Petrazzini, Maria Elena; Bisazza, Angelo
2017-08-01
The ability to utilize numerical information can be adaptive in a number of ecological contexts including foraging, mating, parental care, and anti-predator strategies. Numerical abilities of mammals and birds have been studied both in natural conditions and in controlled laboratory conditions using a variety of approaches. During the last decade this ability was also investigated in some fish species. Here we reviewed the main methods used to study this group, highlighting the strengths and weaknesses of each of the methods used. Fish have only been studied under laboratory conditions and among the methods used with other species, only two have been systematically used in fish-spontaneous choice tests and discrimination learning procedures. In the former case, the choice between two options is observed in a biologically relevant situation and the degree of preference for the larger/smaller group is taken as a measure of the capacity to discriminate the two quantities (e.g., two shoals differing in number). In discrimination learning tasks, fish are trained to select the larger or the smaller of two sets of abstract objects, typically two-dimensional geometric figures, using food or social companions as reward. Beyond methodological differences, what emerges from the literature is a substantial similarity of the numerical abilities of fish with those of other vertebrates studied. Copyright © 2017 Elsevier B.V. All rights reserved.
Animal Allergens and Their Presence in the Environment
Zahradnik, Eva; Raulf, Monika
2014-01-01
Exposure to animal allergens is a major risk factor for sensitization and allergic diseases. Besides mites and cockroaches, the most important animal allergens are derived from mammals. Cat and dog allergies affect the general population; whereas, allergies to rodents or cattle is an occupational problem. Exposure to animal allergens is not limited to direct contact to animals. Based on their aerodynamic properties, mammalian allergens easily become airborne, attach to clothing and hair, and can be spread from one environment to another. For example, the major cat allergen Fel d 1 was frequently found in homes without pets and in public buildings, including schools, day-care centers, and hospitals. Allergen concentrations in a particular environment showed high variability depending on numerous factors. Assessment of allergen exposure levels is a stepwise process that involves dust collection, allergen quantification, and data analysis. Whereas a number of different dust sampling strategies are used, ELISA assays have prevailed in the last years as the standard technique for quantification of allergen concentrations. This review focuses on allergens arising from domestic, farm, and laboratory animals and describes the ubiquity of mammalian allergens in the human environment. It includes an overview of exposure assessment studies carried out in different indoor settings (homes, schools, workplaces) using numerous sampling and analytical methods and summarizes significant factors influencing exposure levels. However, methodological differences among studies have contributed to the variability of the findings and make comparisons between studies difficult. Therefore, a general standardization of methods is needed and recommended. PMID:24624129
Animal allergens and their presence in the environment
Directory of Open Access Journals (Sweden)
Eva eZahradnik
2014-03-01
Full Text Available Exposure to animal allergens is a major risk factor for sensitization and allergic diseases. Besides mites and cockroaches, the most important animal allergens are derived from mammals. Cat and dog allergies affect the general population; whereas, allergies to rodents or cattle is an occupational problem. Exposure to animal allergens is not limited to direct contact to animals. Based on their aerodynamic properties, mammalian allergens easily become airborne, attach to clothing and hair, and can be spread from one environment to another. For example, the major cat allergen Fel d 1 was frequently found in homes without pets and in public buildings, including schools, day care centers and hospitals. Allergen concentrations in a particular environment showed high variability depending on numerous factors.Assessment of allergen exposure levels is a stepwise process that involves dust collection, allergen quantification and data analysis. Whereas a number of different dust sampling strategies are used, ELISA assays have prevailed in the last years as the standard technique for quantification of allergen concentrations. This review focuses on allergens arising from domestic, farm and laboratory animals and describes the ubiquity of mammalian allergens in the human environment. It includes an overview of exposure assessment studies carried out in different indoor settings (homes, schools, workplaces using numerous sampling and analytical methods and summarizes significant factors influencing exposure levels. However, methodological differences among studies have contributed to the variability of the findings and make comparisons between studies difficult. Therefore, a general standardization of methods is needed and recommended.
Directory of Open Access Journals (Sweden)
MIHAI IELENICZ
2013-01-01
Full Text Available Rural tourism is now determined by limited economic opportunities, poor infrastructure, low motivation to possible offers, lack of proper service guarantees. Nearly 500 Romanian villages are already tourist locations, with certain characteristics determined by a heritage item, or complex ones when multiple components lead to various activities. This paper includes a typology of tourist villages in Romania according to the types of practiced tourist activities, insisting on the use of a more comprehensive terminology: tourism in rural environment, participative and creative tourism in rural areas. Tourism becomes a system accepted in the rural environment as a real opportunity for economic development with multiple social consequences. By multiplying tourism potential to meet tourists’ demands, many villages will get tourism valences with various activities in this filed, including environment protection.
Children's Environment in ECEC
DEFF Research Database (Denmark)
Koch, Anette Boye; Laursen, Hanne; Jørgensen, Hanne Hede
2017-01-01
such as play and artwork when they asked to describe the best child environmental practice. Children’s perspectives on their environment still are to be investigated. The study offers knowledge regarding children as active participants in a Nordic ECE culture with educated staff and a long tradition......Danish Legislation prescribes that children’s environment in Early Childhood Education (ECE) is evaluated and enhanced as an integrated part of curriculum work. Children’s perspectives must be included in the efforts. During the last 10 years, pedagogues have endeavoured to include children...... in evaluations of physical, psychological and aesthetic environmental dimensions of education. The present study aims to elucidate how professionals and children co-operate in order to develop children’s environments and study the impact of children’s perspectives on pedagogy and children’s processes of ‘bildung...
Numerical Study of Electric Field Enhanced Combustion
Han, Jie
2016-12-26
Electric fields can be used to change and control flame properties, for example changing flame speed, enhancing flame stability, or reducing pollutant emission. The ions generated in flames are believed to play the primary role. Although experiments have been carried out to study electric field enhanced combustion, they are not sufficient to explain how the ions in a flame are affected by an electric field. It is therefore necessary to investigate the problem through numerical simulations. In the present work, the electric structure of stabilized CH4/air premixed flames at atmospheric pressure within a direct current field is studied using numerical simulations. This study consists of three parts. First, the transport equations are derived from the Boltzmann kinetic equation for each individual species. Second, a general method for computing the diffusivity and mobility of ions in a gas mixture is introduced. Third, the mechanisms for neutral and charged species are improved to give better predictions of the concentrations of charged species, based on experimental data. Following from this, comprehensive numerical results are presented, including the concentrations and fluxes of charged species, the distributions of the electric field and electric potential, and the electric current-voltage relation. Two new concepts introduced with the numerical results are the plasma sheath and dead zone in the premixed flame. A reactive plasma sheath and a Boltzmann relation sheath are discovered in the region near the electrodes. The plasma sheath penetrates into the flame gas when a voltage is applied, and penetrating further if the voltage is higher. The zone outside the region of sheath penetration is defined as the dead zone. With the two concepts, analytical solutions for the electric field, electric potential and current-voltage curve are derived. The solutions directly describe the electric structure of a premixed flame subject to a DC field. These analytical solutions
Gene-environment interplay in depressive symptoms
DEFF Research Database (Denmark)
Petkus, A. J.; Beam, C. R.; Johnson, W.
2017-01-01
that genetic factors play a larger part in the association between depressive symptoms and physical illness for men than for women. For both sexes, across all ages, physical illness may similarly trigger social and health limitations that contribute to depressive symptoms.......Background Numerous factors influence late-life depressive symptoms in adults, many not thoroughly characterized. We addressed whether genetic and environmental influences on depressive symptoms differed by age, sex, and physical illness. Method The analysis sample included 24 436 twins aged 40......-90 years drawn from the Interplay of Genes and Environment across Multiple Studies (IGEMS) Consortium. Biometric analyses tested age, sex, and physical illness moderation of genetic and environmental variance in depressive symptoms. Results Women reported greater depressive symptoms than men. After age 60...
Compound Option Pricing under Fuzzy Environment
Directory of Open Access Journals (Sweden)
Xiandong Wang
2014-01-01
Full Text Available Considering the uncertainty of a financial market includes two aspects: risk and vagueness; in this paper, fuzzy sets theory is applied to model the imprecise input parameters (interest rate and volatility. We present the fuzzy price of compound option by fuzzing the interest and volatility in Geske’s compound option pricing formula. For each α, the α-level set of fuzzy prices is obtained according to the fuzzy arithmetics and the definition of fuzzy-valued function. We apply a defuzzification method based on crisp possibilistic mean values of the fuzzy interest rate and fuzzy volatility to obtain the crisp possibilistic mean value of compound option price. Finally, we present a numerical analysis to illustrate the compound option pricing under fuzzy environment.
Three-Dimensional Numerical Simulation to Mud Turbine for LWD
Yao, Xiaojiang; Dong, Jingxin; Shang, Jie; Zhang, Guanqi
Hydraulic performance analysis was discussed for a type of turbine on generator used for LWD. The simulation models were built by CFD analysis software FINE/Turbo, and full three-dimensional numerical simulation was carried out for impeller group. The hydraulic parameter such as power, speed and pressure drop, were calculated in two kinds of medium water and mud. Experiment was built in water environment. The error of numerical simulation was less than 6%, verified by experiment. Based on this rationalization proposals would be given to choice appropriate impellers, and the rationalization of methods would be explored.
Energy Technology Data Exchange (ETDEWEB)
Park, Ju Yeop; In, Wang Kee; Chun, Tae Hyun; Oh, Dong Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)
2000-02-01
The development of orthogonal 2-dimensional numerical code is made. The present code contains 9 kinds of turbulence models that are widely used. They include a standard k-{epsilon} model and 8 kinds of low Reynolds number ones. They also include 6 kinds of numerical schemes including 5 kinds of low order schemes and 1 kind of high order scheme such as QUICK. To verify the present numerical code, pipe flow, channel flow and expansion pipe flow are solved by this code with various options of turbulence models and numerical schemes and the calculated outputs are compared to experimental data. Furthermore, the discretization error that originates from the use of standard k-{epsilon} turbulence model with wall function is much more diminished by introducing a new grid system than a conventional one in the present code. 23 refs., 58 figs., 6 tabs. (Author)
Statistical physics including applications to condensed matter
Hermann, Claudine
2005-01-01
Statistical Physics bridges the properties of a macroscopic system and the microscopic behavior of its constituting particles, otherwise impossible due to the giant magnitude of Avogadro's number. Numerous systems of today's key technologies -- as e.g. semiconductors or lasers -- are macroscopic quantum objects; only statistical physics allows for understanding their fundamentals. Therefore, this graduate text also focuses on particular applications such as the properties of electrons in solids with applications, and radiation thermodynamics and the greenhouse effect.
The Oceanographic Multipurpose Software Environment (OMUSE v1.0
Directory of Open Access Journals (Sweden)
I. Pelupessy
2017-08-01
Full Text Available In this paper we present the Oceanographic Multipurpose Software Environment (OMUSE. OMUSE aims to provide a homogeneous environment for existing or newly developed numerical ocean simulation codes, simplifying their use and deployment. In this way, numerical experiments that combine ocean models representing different physics or spanning different ranges of physical scales can be easily designed. Rapid development of simulation models is made possible through the creation of simple high-level scripts. The low-level core of the abstraction in OMUSE is designed to deploy these simulations efficiently on heterogeneous high-performance computing resources. Cross-verification of simulation models with different codes and numerical methods is facilitated by the unified interface that OMUSE provides. Reproducibility in numerical experiments is fostered by allowing complex numerical experiments to be expressed in portable scripts that conform to a common OMUSE interface. Here, we present the design of OMUSE as well as the modules and model components currently included, which range from a simple conceptual quasi-geostrophic solver to the global circulation model POP (Parallel Ocean Program. The uniform access to the codes' simulation state and the extensive automation of data transfer and conversion operations aids the implementation of model couplings. We discuss the types of couplings that can be implemented using OMUSE. We also present example applications that demonstrate the straightforward model initialization and the concurrent use of data analysis tools on a running model. We give examples of multiscale and multiphysics simulations by embedding a regional ocean model into a global ocean model and by coupling a surface wave propagation model with a coastal circulation model.
Numerical determination of axisymmetric toroidal magnetohydrodynamic equilibria
International Nuclear Information System (INIS)
Johnson, J.L.; Dalhed, H.E.; Greene, J.M.
1978-07-01
Numerical schemes for the determination of stationary axisymmetric toroidal equilibria appropriate for modeling real experimental devices are given. Iterative schemes are used to solve the elliptic nonlinear partial differential equation for the poloidal flux function psi. The principal emphasis is on solving the free boundary (plasma-vacuum interface) equilibrium problem where external current-carrying toroidal coils support the plasma column, but fixed boundary (e.g., conducting shell) cases are also included. The toroidal current distribution is given by specifying the pressure and either the poloidal current or the safety factor profiles as functions of psi. Examples of the application of the codes to tokamak design at PPPL are given
Numerical investigations of hybrid rocket engines
Betelin, V. B.; Kushnirenko, A. G.; Smirnov, N. N.; Nikitin, V. F.; Tyurenkova, V. V.; Stamov, L. I.
2018-03-01
Paper presents the results of numerical studies of hybrid rocket engines operating cycle including unsteady-state transition stage. A mathematical model is developed accounting for the peculiarities of diffusion combustion of fuel in the flow of oxidant, which is composed of oxygen-nitrogen mixture. Three dimensional unsteady-state simulations of chemically reacting gas mixture above thermochemically destructing surface are performed. The results show that the diffusion combustion brings to strongly non-uniform fuel mass regression rate in the flow direction. Diffusive deceleration of chemical reaction brings to the decrease of fuel regression rate in the longitudinal direction.
Numerical Simulations Of Flagellated Micro-Swimmers
Rorai, Cecilia; Markesteijn, Anton; Zaitstev, Mihail; Karabasov, Sergey
2017-11-01
We study flagellated microswimmers locomotion by representing the entire swimmer body. We discuss and contrast the accuracy and computational cost of different numerical approaches including the Resistive Force Theory, the Regularized Stokeslet Method and the Finite Element Method. We focus on how the accuracy of the methods in reproducing the swimming trajectories, velocities and flow field, compares to the sensitivity of these quantities to certain physical parameters, such as the body shape and the location of the center of mass. We discuss the opportunity and physical relevance of retaining inertia in our models. Finally, we present some preliminary results toward collective motion simulations. Marie Skodowska-Curie Individual Fellowship.
Numerically abnormal chromosome constitutions in humans
Energy Technology Data Exchange (ETDEWEB)
NONE
1993-12-31
Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.
Numerical methods for differential equations and applications
International Nuclear Information System (INIS)
Ixaru, L.G.
1984-01-01
This book is addressed to persons who, without being professionals in applied mathematics, are often faced with the problem of numerically solving differential equations. In each of the first three chapters a definite class of methods is discussed for the solution of the initial value problem for ordinary differential equations: multistep methods; one-step methods; and piecewise perturbation methods. The fourth chapter is mainly focussed on the boundary value problems for linear second-order equations, with a section devoted to the Schroedinger equation. In the fifth chapter the eigenvalue problem for the radial Schroedinger equation is solved in several ways, with computer programs included. (Auth.)
Numerical simulation of Higgs models
International Nuclear Information System (INIS)
Jaster, A.
1995-10-01
The SU(2) Higgs and the Schwinger model on the lattice were analysed. Numerical simulations of the SU(2) Higgs model were performed to study the finite temperature electroweak phase transition. With the help of the multicanonical method the distribution of an order parameter at the phase transition point was measured. This was used to obtain the order of the phase transition and the value of the interface tension with the histogram method. Numerical simulations were also performed at zero temperature to perform renormalization. The measured values for the Wilson loops were used to determine the static potential and from this the renormalized gauge coupling. The Schwinger model was simulated at different gauge couplings to analyse the properties of the Kaplan-Shamir fermions. The prediction that the mass parameter gets only multiplicative renormalization was tested and verified. (orig.)
Numerical Modelling of Electrical Discharges
International Nuclear Information System (INIS)
Durán-Olivencia, F J; Pontiga, F; Castellanos, A
2014-01-01
The problem of the propagation of an electrical discharge between a spherical electrode and a plane has been solved by means of finite element methods (FEM) using a fluid approximation and assuming weak ionization and local equilibrium with the electric field. The numerical simulation of this type of problems presents the usual difficulties of convection-diffusion-reaction problems, in addition to those associated with the nonlinearities of the charged species velocities, the formation of steep gradients of the electric field and particle densities, and the coexistence of very different temporal scales. The effect of using different temporal discretizations for the numerical integration of the corresponding system of partial differential equations will be here investigated. In particular, the so-called θ-methods will be used, which allows to implement implicit, semi-explicit and fully explicit schemes in a simple way
Numerical Modeling of Shoreline Undulations
DEFF Research Database (Denmark)
Kærgaard, Kasper Hauberg
model has been developed which describes the longshore sediment transport along arbitrarily shaped shorelines. The numerical model is based on a spectral wave model, a depth integrated flow model, a wave-phase resolving sediment transport description and a one-line shoreline model. First the theoretical...... of the feature and under predicts the migration speeds of the features. On the second shoreline, the shoreline model predicts undulations lengths which are longer than the observed undulations. Lastly the thesis considers field measurements of undulations of the bottom bathymetry along an otherwise straight...... length of the shoreline undulations is determined in the linear regime using a shoreline stability analysis based on the numerical model. The analysis shows that the length of the undulations in the linear regime depends on the incoming wave conditions and on the coastal profile. For larger waves...
Numerical simulation of fire vortex
Barannikova, D. D.; Borzykh, V. E.; Obukhov, A. G.
2018-05-01
The article considers the numerical simulation of the swirling flow of air around the smoothly heated vertical cylindrical domain in the conditions of gravity and Coriolis forces action. The solutions of the complete system of Navie-Stocks equations are numerically solved at constant viscosity and heat conductivity factors. Along with the proposed initial and boundary conditions, these solutions describe the complex non-stationary 3D flows of viscous compressible heat conducting gas. For various instants of time of the initial flow formation stage using the explicit finite-difference scheme the calculations of all gas dynamics parameters, that is density, temperature, pressure and three velocity components of gas particles, have been run. The current instant lines corresponding to the trajectories of the particles movement in the emerging flow have been constructed. A negative direction of the air flow swirling occurred in the vertical cylindrical domain heating has been defined.
Numerical and Evolutionary Optimization Workshop
Trujillo, Leonardo; Legrand, Pierrick; Maldonado, Yazmin
2017-01-01
This volume comprises a selection of works presented at the Numerical and Evolutionary Optimization (NEO) workshop held in September 2015 in Tijuana, Mexico. The development of powerful search and optimization techniques is of great importance in today’s world that requires researchers and practitioners to tackle a growing number of challenging real-world problems. In particular, there are two well-established and widely known fields that are commonly applied in this area: (i) traditional numerical optimization techniques and (ii) comparatively recent bio-inspired heuristics. Both paradigms have their unique strengths and weaknesses, allowing them to solve some challenging problems while still failing in others. The goal of the NEO workshop series is to bring together people from these and related fields to discuss, compare and merge their complimentary perspectives in order to develop fast and reliable hybrid methods that maximize the strengths and minimize the weaknesses of the underlying paradigms. Throu...
Nuclear physics and optoelectronics presence in industry, medicine and environment
International Nuclear Information System (INIS)
Robu, Maria; Peteu, Gh.
2000-01-01
This paper reveals applications of Nuclear Physics and Optoelectronics in numerous fields of interest in industry, medicine, environment. In the first part of the work basic elements are analyzed, among which: - the large possibilities offered by the investigation, analysis and testing techniques based on nuclear physics and optoelectronics; - the superior qualitative and quantitative characteristics of these techniques, with varied applicability in fields from industry, medicine and environment. These applications refers to: - elemental analyses of content and impurities; - non-destructive testing with X and gamma radiations; - investigations with radioactive and activable tracers in trophic chains as for instance, ground-vegetation-products-consumers-environment, including also the systemic pollution factors; - complex investigations in the interface tritium-vegetation-environment-humans; - techniques and radiopharmaceutical products for medical investigations; - determinations and automatic control for levels, density, thickness, humidity, surfaces covering; - monitoring by means of remote sensing for the evaluation of the environment, vegetation and pollution factors; - applications and production of laser and UV installations; - connections through optical fibres resistant to radiations; - imaging and medical bioengineering; - advances in X ray, laser and ultrasonic radiology; - monitoring with radiations beams. In the final part, there are presented examples of optoelectronics and nuclear physics applications in fields in industry, medicine and environment, with special stress on their basic characteristics and efficiency. (authors)
Including Critical Thinking and Problem Solving in Physical Education
Pill, Shane; SueSee, Brendan
2017-01-01
Many physical education curriculum frameworks include statements about the inclusion of critical inquiry processes and the development of creativity and problem-solving skills. The learning environment created by physical education can encourage or limit the application and development of the learners' cognitive resources for critical and creative…
Interviewing Objects: Including Educational Technologies as Qualitative Research Participants
Adams, Catherine A.; Thompson, Terrie Lynn
2011-01-01
This article argues the importance of including significant technologies-in-use as key qualitative research participants when studying today's digitally enhanced learning environments. We gather a set of eight heuristics to assist qualitative researchers in "interviewing" technologies-in-use (or other relevant objects), drawing on concrete…
Visual Impairments, "Including Blindness." NICHCY Disability Fact Sheet #13
National Dissemination Center for Children with Disabilities, 2012
2012-01-01
Vision is one of the five senses. Being able to see gives tremendous access to learning about the world around--people's faces and the subtleties of expression, what different things look like and how big they are, and the physical environments, including approaching hazards. When a child has a visual impairment, it is cause for immediate…
Numerical Tokamak Project code comparison
International Nuclear Information System (INIS)
Waltz, R.E.; Cohen, B.I.; Beer, M.A.
1994-01-01
The Numerical Tokamak Project undertook a code comparison using a set of TFTR tokamak parameters. Local radial annulus codes of both gyrokinetic and gyrofluid types were compared for both slab and toroidal case limits assuming ion temperature gradient mode turbulence in a pure plasma with adiabatic electrons. The heat diffusivities were found to be in good internal agreement within ± 50% of the group average over five codes
Numerical algorithms in secondary creep
International Nuclear Information System (INIS)
Feijoo, R.A.; Taroco, E.
1980-01-01
The problem of stationary creep is presented as well as its variational formulation, when weak constraints are established, capable of assuring one single solution. A second, so-called elasto-creep problem, is further analysed, together with its variational formulation. It is shown that its stationary solution coincides with that of the stationary creep and the advantages of this formulation with respect to the former one is emphasized. Some numerical applications showing the efficiency of the method propesed are finally presented [pt
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.
Modeling Electric Double-Layers Including Chemical Reaction Effects
DEFF Research Database (Denmark)
Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.
2014-01-01
A physicochemical and numerical model for the transient formation of an electric double-layer between an electrolyte and a chemically-active flat surface is presented, based on a finite elements integration of the nonlinear Nernst-Planck-Poisson model including chemical reactions. The model works...... for symmetric and asymmetric multi-species electrolytes and is not limited to a range of surface potentials. Numerical simulations are presented, for the case of a CaCO3 electrolyte solution in contact with a surface with rate-controlled protonation/deprotonation reactions. The surface charge and potential...... are determined by the surface reactions, and therefore they depends on the bulk solution composition and concentration...
Numerical ability predicts mortgage default.
Gerardi, Kristopher; Goette, Lorenz; Meier, Stephan
2013-07-09
Unprecedented levels of US subprime mortgage defaults precipitated a severe global financial crisis in late 2008, plunging much of the industrialized world into a deep recession. However, the fundamental reasons for why US mortgages defaulted at such spectacular rates remain largely unknown. This paper presents empirical evidence showing that the ability to perform basic mathematical calculations is negatively associated with the propensity to default on one's mortgage. We measure several aspects of financial literacy and cognitive ability in a survey of subprime mortgage borrowers who took out loans in 2006 and 2007, and match them to objective, detailed administrative data on mortgage characteristics and payment histories. The relationship between numerical ability and mortgage default is robust to controlling for a broad set of sociodemographic variables, and is not driven by other aspects of cognitive ability. We find no support for the hypothesis that numerical ability impacts mortgage outcomes through the choice of the mortgage contract. Rather, our results suggest that individuals with limited numerical ability default on their mortgage due to behavior unrelated to the initial choice of their mortgage.
Numerical ability predicts mortgage default
Gerardi, Kristopher; Goette, Lorenz; Meier, Stephan
2013-01-01
Unprecedented levels of US subprime mortgage defaults precipitated a severe global financial crisis in late 2008, plunging much of the industrialized world into a deep recession. However, the fundamental reasons for why US mortgages defaulted at such spectacular rates remain largely unknown. This paper presents empirical evidence showing that the ability to perform basic mathematical calculations is negatively associated with the propensity to default on one’s mortgage. We measure several aspects of financial literacy and cognitive ability in a survey of subprime mortgage borrowers who took out loans in 2006 and 2007, and match them to objective, detailed administrative data on mortgage characteristics and payment histories. The relationship between numerical ability and mortgage default is robust to controlling for a broad set of sociodemographic variables, and is not driven by other aspects of cognitive ability. We find no support for the hypothesis that numerical ability impacts mortgage outcomes through the choice of the mortgage contract. Rather, our results suggest that individuals with limited numerical ability default on their mortgage due to behavior unrelated to the initial choice of their mortgage. PMID:23798401
International Nuclear Information System (INIS)
Greenhalgh, Geoffrey.
1986-01-01
The findings of the House of Commons Environment Committee (March 1986) on radioactive waste are examined. The report includes 43 recommendations and conclusions, many of which are directed at improving public acceptance of nuclear power, rather than constituting an attack on the nuclear industry. Some of the major topics considered in the report include: waste disposal, waste classification, waste disposal policy, discharges, reprocessing, and public acceptance. (UK)
Numerical simulation of pollutant dispersion in urban roadway tunnels
Directory of Open Access Journals (Sweden)
Jingliang Dong
2017-03-01
Full Text Available Vehicular toxic emissions can easily contaminate the air quality of the enclosed tunnel environment, especially during rush hours with traffic jam events or low vehicle speeds, which poses serious health hazards to road utilizers. The piston effect generated by moving vehicles was normally considered adequate to discharge vitiated air out of short tunnel based on a typical driving speed. However, complex traffic conditions may yield unexpected consequences on in-tunnel air quality levels. This study numerically investigated the CO2 concentration to identify the in-tunnel pollutant dispersion under three traffic conditions including severe traffic congestion and traffic flow with low vehicle speeds. Fan conditions were considered to model the influence of mechanical winds on pollutant dispersion and comparison with vehicular piston effect was also performed. The results revealed elevated pollutant concentration regions were found at the vicinity of near-ground region and tunnel downstream. The vehicular piston effect can sufficiently remove the in-tunnel vehicular emissions when vehicles travel at relatively higher speed. However, pollutant accumulation occurs when vehicles are idling or moving at slow speed. Compared with traffic piston effect at high travelling speed, the mechanical ventilation of ceiling mounted fans only generate a limited contribution to the removal of emissions.
Wünnemann, K.; Collins, G. S.; Weiss, R.
2010-12-01
The strike of a cosmic body into a marine environment differs in several respects from impact on land. Oceans cover approximately 70% of the Earth's surface, implying not only that oceanic impact is a very likely scenario for future impacts but also that most impacts in Earth's history must have happened in marine environments. Therefore, the study of oceanic impact is imperative in two respects: (1) to quantify the hazard posed by future oceanic impacts, including the potential threat of large impact-generated tsunami-like waves, and (2) to reconstruct Earth's impact record by accounting for the large number of potentially undiscovered crater structures in the ocean crust. Reconstruction of the impact record is of crucial importance both for assessing the frequency of collision events in the past and for better predicting the probability of future impact. We summarize the advances in the study of oceanic impact over the last decades and focus in particular on how numerical models have improved our understanding of cratering in the oceanic environment and the generation of waves by impact. We focus on insight gleaned from numerical modeling studies into the deceleration of the projectile by the water, cratering of the ocean floor, the late stage modification of the crater due to gravitational collapse, and water resurge. Furthermore, we discuss the generation and propagation of large tsunami-like waves as a result of a strike of a cosmic body in marine environments.
Stochastic numerical methods an introduction for students and scientists
Toral, Raul
2014-01-01
Stochastic Numerical Methods introduces at Master level the numerical methods that use probability or stochastic concepts to analyze random processes. The book aims at being rather general and is addressed at students of natural sciences (Physics, Chemistry, Mathematics, Biology, etc.) and Engineering, but also social sciences (Economy, Sociology, etc.) where some of the techniques have been used recently to numerically simulate different agent-based models. Examples included in the book range from phase-transitions and critical phenomena, including details of data analysis (extraction of critical exponents, finite-size effects, etc.), to population dynamics, interfacial growth, chemical reactions, etc. Program listings are integrated in the discussion of numerical algorithms to facilitate their understanding. From the contents: Review of Probability ConceptsMonte Carlo IntegrationGeneration of Uniform and Non-uniformRandom Numbers: Non-correlated ValuesDynamical MethodsApplications to Statistical MechanicsIn...
Numerical issues for liquid-metal boiling transient analysis
International Nuclear Information System (INIS)
Rowe, D.S.
1986-01-01
The large liquid-to-vapor density ratio of a boiling liquid-metal leads to a very abrupt change of the two-phase mixture density at the inception of boiling. Unfortunately, the strong dependence of mixture density on pressure leads to a key numerical issue that adversely affects the behavior of numerical solutions. The difficulties can be reduced by using techniques that acknowledge this functional behavior at the start of boiling. Some of the methods used include a spatially averaged density function, mathematical smoothing, and under relaxation. Nonequilibrium two-fluid models also seem to offer aid in obtaining reliable numerical solutions. (author)
Modular numerical tool for gas turbine simulation
Sampedro Casis, Rodrigo
2015-01-01
In this work a free tool for the simulation of turboprops was implemented, capable of simulating the various components of a jet engine, separately or in conjunction, with different degrees of thermodynamic modelling or complexity, in order to simulate an entire jet engine. The main characteristics of this software includes its compatibility, open code and GNU license, non-existing in today's market. Furthermore, the tool was designed with a greater flexibility and a more adapted work environ...
Numerical simulation of GEW equation using RBF collocation method
Directory of Open Access Journals (Sweden)
Hamid Panahipour
2012-08-01
Full Text Available The generalized equal width (GEW equation is solved numerically by a meshless method based on a global collocation with standard types of radial basis functions (RBFs. Test problems including propagation of single solitons, interaction of two and three solitons, development of the Maxwellian initial condition pulses, wave undulation and wave generation are used to indicate the efficiency and accuracy of the method. Comparisons are made between the results of the proposed method and some other published numerical methods.
Numerical Simulation of Particle Motion in a Curved Channel
Liu, Yi; Nie, Deming
2018-01-01
In this work the lattice Boltzmann method (LBM) is used to numerically study the motion of a circular particle in a curved channel at intermediate Reynolds numbers (Re). The effects of the Reynolds number and the initial particle position are taken into account. Numerical results include the streamlines, particle trajectories and final equilibrium positions. It has been found that the particle is likely to migrate to a similar equilibrium position irrespective of its initial position when Re is large.
LHCb Dockerized Build Environment
Clemencic, M.; Belin, M.; Closier, J.; Couturier, B.
2017-10-01
Used as lightweight virtual machines or as enhanced chroot environments, Linux containers, and in particular the Docker abstraction over them, are more and more popular in the virtualization communities. The LHCb Core Software team decided to investigate how to use Docker containers to provide stable and reliable build environments for the different supported platforms, including the obsolete ones which cannot be installed on modern hardware, to be used in integration builds, releases and by any developer. We present here the techniques and procedures set up to define and maintain the Docker images and how these images can be used to develop on modern Linux distributions for platforms otherwise not accessible.
Numerical study of nonspherical black hole accretion
International Nuclear Information System (INIS)
Hawley, J.F.
1984-01-01
This thesis describes in detail a two-dimensional, axisymmetric computer code for calculating fully relativistic ideal gas hydrodynamics around a Kerr black hole. The aim is to study fully dynamic inviscid fluid accretion onto black holes, as well as to study the evolution and development of nonlinear instabilities in pressure supported accretion disks. In order to fully calibrate and document the code, certain analytic solutions for shock tubes and special accretion flows are derived; these solutions form the basis for code testing. The numerical techniques used are developed and discussed. A variety of alternate differencing schemes are compared on an analytic test bed. Some discussion is devoted to general issues in finite differencing. The working code is calibrated using analytically solvable accretion problems, including the radial accretion of dust and of fluid with pressure (Bondi accretion). Two dimensional test problems include the spiraling infall of low angular momentum fluid, the formation of a pressure supported torus, and the stable evolution of a torus. A series of numerical models are discussed and illustrated with selected plots
Numerical simulation of real-world flows
Energy Technology Data Exchange (ETDEWEB)
Hayase, Toshiyuki, E-mail: hayase@ifs.tohoku.ac.jp [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan)
2015-10-15
Obtaining real flow information is important in various fields, but is a difficult issue because measurement data are usually limited in time and space, and computational results usually do not represent the exact state of real flows. Problems inherent in the realization of numerical simulation of real-world flows include the difficulty in representing exact initial and boundary conditions and the difficulty in representing unstable flow characteristics. This article reviews studies dealing with these problems. First, an overview of basic flow measurement methodologies and measurement data interpolation/approximation techniques is presented. Then, studies on methods of integrating numerical simulation and measurement, namely, four-dimensional variational data assimilation (4D-Var), Kalman filters (KFs), state observers, etc are discussed. The first problem is properly solved by these integration methodologies. The second problem can be partially solved with 4D-Var in which only initial and boundary conditions are control parameters. If an appropriate control parameter capable of modifying the dynamical structure of the model is included in the formulation of 4D-Var, unstable modes are properly suppressed and the second problem is solved. The state observer and KFs also solve the second problem by modifying mathematical models to stabilize the unstable modes of the original dynamical system by applying feedback signals. These integration methodologies are now applied in simulation of real-world flows in a wide variety of research fields. Examples are presented for basic fluid dynamics and applications in meteorology, aerospace, medicine, etc. (topical review)
Mathematica with a Numerical Methods Course
Varley, Rodney
2003-04-01
An interdisciplinary "Numerical Methods" course has been shared between physics, mathematics and computer science since 1992 at Hunter C. Recently, the lectures and workshops for this course have become formalized and placed on the internet at http://www.ph.hunter.cuny.edu (follow the links "Course Listings and Websites" >> "PHYS385 (Numerical Methods)". Mathematica notebooks for the lectures are available for automatic download (by "double clicking" the lecture icon) for student use in the classroom or at home. AOL (or Netscape/Explorer) can be used provided Mathematica (or the "free" MathReader) has been made a "helper application". Using Mathematica has the virtue that mathematical equations (no LaTex required) can easily be included with the text and Mathematica's graphing is easy to use. Computational cells can be included within the notebook and students may easily modify the calculation to see the result of "what if..." questions. Homework is sent as Mathematica notebooks to the instructor via the internet and the corrected workshops are returned in the same manner. Most exam questions require computational solutions.
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)
Exercises in experimental physics including complete solutions
International Nuclear Information System (INIS)
Fleischmann, R.; Loos, G.
1978-01-01
This collection of exercises is not only addressed to students of physics but also to scientists of other branches and to engineers. Possibilities are offered to the student to gain control on his growing knowledge from the beginning of his studies until the examination. The individual exercises are linked thematically and are mostly composed by several single tasks. Complete and detailed numerical solutions are presented. The topics covered are: (1) Mechanics, (2) thermodynamics, (3) oscillations and their propagation, (4) electricity and magnetism, (5) atomic physics, and (6) nuclear physics. (KBE)
Numerical Analysis of Electromagnetic Fields in Multiscale Model
International Nuclear Information System (INIS)
Ma Ji; Fang Guang-You; Ji Yi-Cai
2015-01-01
Modeling technique for electromagnetic fields excited by antennas is an important topic in computational electromagnetics, which is concerned with the numerical solution of Maxwell's equations. In this paper, a novel hybrid technique that combines method of moments (MoM) with finite-difference time-domain (FDTD) method is presented to handle the problem. This approach employed Huygen's principle to realize the hybridization of the two classical numerical algorithms. For wideband electromagnetic data, the interpolation scheme is used in the MoM based on the dyadic Green's function. On the other hand, with the help of equivalence principle, the scattered electric and magnetic fields on the Huygen's surface calculated by MoM are taken as the sources for FDTD. Therefore, the electromagnetic fields in the environment can be obtained by employing finite-difference time-domain method. Finally, numerical results show the validity of the proposed technique by analyzing two canonical samples. (paper)
Mathematical modeling and numerical simulation of Czochralski Crystal Growth
Energy Technology Data Exchange (ETDEWEB)
Jaervinen, J.; Nieminen, R. [Center for Scientific Computing, Espoo (Finland)
1996-12-31
A detailed mathematical model and numerical simulation tools based on the SUPG Finite Element Method for the Czochralski crystal growth has been developed. In this presentation the mathematical modeling and numerical simulation of the melt flow and the temperature distribution in a rotationally symmetric crystal growth environment is investigated. The temperature distribution and the position of the free boundary between the solid and liquid phases are solved by using the Enthalpy method. Heat inside of the Czochralski furnace is transferred by radiation, conduction and convection. The melt flow is governed by the incompressible Navier-Stokes equations coupled with the enthalpy equation. The melt flow is numerically demonstrated and the temperature distribution in the whole Czochralski furnace. (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)
Mathematical modeling and numerical simulation of Czochralski Crystal Growth
Energy Technology Data Exchange (ETDEWEB)
Jaervinen, J; Nieminen, R [Center for Scientific Computing, Espoo (Finland)
1997-12-31
A detailed mathematical model and numerical simulation tools based on the SUPG Finite Element Method for the Czochralski crystal growth has been developed. In this presentation the mathematical modeling and numerical simulation of the melt flow and the temperature distribution in a rotationally symmetric crystal growth environment is investigated. The temperature distribution and the position of the free boundary between the solid and liquid phases are solved by using the Enthalpy method. Heat inside of the Czochralski furnace is transferred by radiation, conduction and convection. The melt flow is governed by the incompressible Navier-Stokes equations coupled with the enthalpy equation. The melt flow is numerically demonstrated and the temperature distribution in the whole Czochralski furnace. (author)
Conceptual and Numerical Models for UZ Flow and Transport
International Nuclear Information System (INIS)
Liu, H.
2000-01-01
The purpose of this Analysis/Model Report (AMR) is to document the conceptual and numerical models used for modeling of unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This is in accordance with ''AMR Development Plan for U0030 Conceptual and Numerical Models for Unsaturated Zone (UZ) Flow and Transport Processes, Rev 00''. The conceptual and numerical modeling approaches described in this AMR are used for models of UZ flow and transport in fractured, unsaturated rock under ambient and thermal conditions, which are documented in separate AMRs. This AMR supports the UZ Flow and Transport Process Model Report (PMR), the Near Field Environment PMR, and the following models: Calibrated Properties Model; UZ Flow Models and Submodels; Mountain-Scale Coupled Processes Model; Thermal-Hydrologic-Chemical (THC) Seepage Model; Drift Scale Test (DST) THC Model; Seepage Model for Performance Assessment (PA); and UZ Radionuclide Transport Models
Smith, David Eugene
1911-01-01
The numbers that we call Arabic are so familiar throughout Europe and the Americas that it can be difficult to realize that their general acceptance in commercial transactions is a matter of only the last four centuries and they still remain unknown in parts of the world.In this volume, one of the earliest texts to trace the origin and development of our number system, two distinguished mathematicians collaborated to bring together many fragmentary narrations to produce a concise history of Hindu-Arabic numerals. Clearly and succinctly, they recount the labors of scholars who have studied the
Radiation transport in numerical astrophysics
International Nuclear Information System (INIS)
Lund, C.M.
1983-02-01
In this article, we discuss some of the numerical techniques developed by Jim Wilson and co-workers for the calculation of time-dependent radiation flow. Difference equations for multifrequency transport are given for both a discrete-angle representation of radiation transport and a Fick's law-like representation. These methods have the important property that they correctly describe both the streaming and diffusion limits of transport theory in problems where the mean free path divided by characteristic distances varies from much less than one to much greater than one. They are also stable for timesteps comparable to the changes in physical variables, rather than being limited by stability requirements
Odelouca Dam Construction: Numerical Analysis
Brito, A.; Maranha, J. R.; Caldeira, L.
2012-01-01
Odelouca dam is an embankment dam, with 76 m height, recently constructed in the south of Portugal. It is zoned with a core consisting of colluvial and residual schist soil and with soil-rockfill mixtures making up the shells (weathered schist with a significant fraction of coarse sized particles). This paper presents a numerical analysis of Odelouca Dam`s construction. The material con-stants of the soil model used are determined from a comprehensive testing programme carried out in the C...
On numerically pluricanonical cyclic coverings
International Nuclear Information System (INIS)
Kulikov, V S; Kharlamov, V M
2014-01-01
We investigate some properties of cyclic coverings f:Y→X (where X is a complex surface of general type) branched along smooth curves B⊂X that are numerically equivalent to a multiple of the canonical class of X. Our main results concern coverings of surfaces of general type with p g =0 and Miyaoka-Yau surfaces. In particular, such coverings provide new examples of multi-component moduli spaces of surfaces with given Chern numbers and new examples of surfaces that are not deformation equivalent to their complex conjugates
Numerical methods for image registration
Modersitzki, Jan
2003-01-01
Based on the author's lecture notes and research, this well-illustrated and comprehensive text is one of the first to provide an introduction to image registration with particular emphasis on numerical methods in medical imaging. Ideal for researchers in industry and academia, it is also a suitable study guide for graduate mathematicians, computer scientists, engineers, medical physicists, and radiologists.Image registration is utilised whenever information obtained from different viewpoints needs to be combined or compared and unwanted distortion needs to be eliminated. For example, CCTV imag
Disruptive Innovation in Numerical Hydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Waltz, Jacob I. [Los Alamos National Laboratory
2012-09-06
We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.
Gyrotactic trapping: A numerical study
Ghorai, S.
2016-04-01
Gyrotactic trapping is a mechanism proposed by Durham et al. ["Disruption of vertical motility by shear triggers formation of thin Phytoplankton layers," Science 323, 1067-1070 (2009)] to explain the formation of thin phytoplankton layer just below the ocean surface. This mechanism is examined numerically using a rational model based on the generalized Taylor dispersion theory. The crucial role of sedimentation speed in the thin layer formation is demonstrated. The effects of variation in different parameters on the thin layer formation are also investigated.
Results from Numerical General Relativity
Baker, John G.
2011-01-01
For several years numerical simulations have been revealing the details of general relativity's predictions for the dynamical interactions of merging black holes. I will review what has been learned of the rich phenomenology of these mergers and the resulting gravitational wave signatures. These wave forms provide a potentially observable record of the powerful astronomical events, a central target of gravitational wave astronomy. Asymmetric radiation can produce a thrust on the system which may accelerate the single black hole resulting from the merger to high relative velocity.
Evaluation of wave runup predictions from numerical and parametric models
Stockdon, Hilary F.; Thompson, David M.; Plant, Nathaniel G.; Long, Joseph W.
2014-01-01
Wave runup during storms is a primary driver of coastal evolution, including shoreline and dune erosion and barrier island overwash. Runup and its components, setup and swash, can be predicted from a parameterized model that was developed by comparing runup observations to offshore wave height, wave period, and local beach slope. Because observations during extreme storms are often unavailable, a numerical model is used to simulate the storm-driven runup to compare to the parameterized model and then develop an approach to improve the accuracy of the parameterization. Numerically simulated and parameterized runup were compared to observations to evaluate model accuracies. The analysis demonstrated that setup was accurately predicted by both the parameterized model and numerical simulations. Infragravity swash heights were most accurately predicted by the parameterized model. The numerical model suffered from bias and gain errors that depended on whether a one-dimensional or two-dimensional spatial domain was used. Nonetheless, all of the predictions were significantly correlated to the observations, implying that the systematic errors can be corrected. The numerical simulations did not resolve the incident-band swash motions, as expected, and the parameterized model performed best at predicting incident-band swash heights. An assimilated prediction using a weighted average of the parameterized model and the numerical simulations resulted in a reduction in prediction error variance. Finally, the numerical simulations were extended to include storm conditions that have not been previously observed. These results indicated that the parameterized predictions of setup may need modification for extreme conditions; numerical simulations can be used to extend the validity of the parameterized predictions of infragravity swash; and numerical simulations systematically underpredict incident swash, which is relatively unimportant under extreme conditions.
Mathematical models and numerical simulation in electromagnetism
Bermúdez, Alfredo; Salgado, Pilar
2014-01-01
The book represents a basic support for a master course in electromagnetism oriented to numerical simulation. The main goal of the book is that the reader knows the boundary-value problems of partial differential equations that should be solved in order to perform computer simulation of electromagnetic processes. Moreover it includes a part devoted to electric circuit theory based on ordinary differential equations. The book is mainly oriented to electric engineering applications, going from the general to the specific, namely, from the full Maxwell’s equations to the particular cases of electrostatics, direct current, magnetostatics and eddy currents models. Apart from standard exercises related to analytical calculus, the book includes some others oriented to real-life applications solved with MaxFEM free simulation software.
Numerical simulation of distributed parameter processes
Colosi, Tiberiu; Unguresan, Mihaela-Ligia; Muresan, Vlad
2013-01-01
The present monograph defines, interprets and uses the matrix of partial derivatives of the state vector with applications for the study of some common categories of engineering. The book covers broad categories of processes that are formed by systems of partial derivative equations (PDEs), including systems of ordinary differential equations (ODEs). The work includes numerous applications specific to Systems Theory based on Mpdx, such as parallel, serial as well as feed-back connections for the processes defined by PDEs. For similar, more complex processes based on Mpdx with PDEs and ODEs as components, we have developed control schemes with PID effects for the propagation phenomena, in continuous media (spaces) or discontinuous ones (chemistry, power system, thermo-energetic) or in electro-mechanics (railway – traction) and so on. The monograph has a purely engineering focus and is intended for a target audience working in extremely diverse fields of application (propagation phenomena, diffusion, hydrodyn...
DEFF Research Database (Denmark)
Meyer, Jan-Henrik
2011-01-01
Environmental policy has become an important area of European Union (EU) policy making, even though it had not originally been foreseen in the Treaty of Rome. Its emergence in the early 1970s can be understood as a result of a transfer of the novel policy idea of the environment to the European...... of the environment as a political concept emerging in the context of international organizations at the time. Secondly, an analysis of the first Environmental Action Programme of 1973 will be used to show how the EC conceptualized the environment, including the definition of problems and potential remedies. Thirdly...... level. This paper thus inquires into the emergence of a European environmental policy from a diffusion of ideas perspective. Rather than focusing on multi-level policy making it seeks to trace the diffusion of environmental ideas from the level of international organizations to the European Communities...
Energy Technology Data Exchange (ETDEWEB)
Trivedi, R N [Fertilizer Association of India, New Delhi
1977-12-01
Power generation from radioisotopes is one of the major applications of nuclear energy for peaceful purposes and is in practice in over twenty countries including India. Other well-known applications of radioactive substances are in medicine, industry, scientific and industrial research programs, and nuclear weapons. The only serious disadvantage with the radioisotopes and their waste products is the constant release of radiation energy which contaminates the environment and endangers the life. An attempt has been made to identify the major sources of radioactivity in the environment and assess its potential impact on the environment. Recent developments in safety measures for prevention of contamination and control of radioactivity and in radioactive wastes management are also discussed.
Radiation environment at Kalpakkam
International Nuclear Information System (INIS)
Iyengar, M.A.R.
1989-01-01
Nuclear facilities located at Kalpakkam in Tamil Nadu State of India include at present nuclear power reactors, a fast breeder reactor, a nuclear research centre and a waste management facility. Active wastes generated at the site are collected, treated and safely disposed. High-level wastes are stored underground in RCC trenches and tile hole and low-level wastes in the from of liquid effluents are discharged into the sea. Off-gases are dispersed through stacks in the atmosphere. Environmental survey laboratory established at the site in 1974 carries out radiation surveillance of the environment, evaluates radiological impacts on environment and public, and assesses radiation exposure of the population. It is observed that even after five years of operation of the nuclear power station, radioactivity and radiation levels in the environment have virtually remained at the pre-operational levels. (M.G.B.). 14 figs., 4 tabs
Contingencies: Learning Numerical and Emotional Associations in an Uncertain World
Langhe, Bart
2011-01-01
textabstractThe ability to learn about the relation or covariation between events happening in the world is probably the most critical aspect of human cognition. This dissertation examines how the human mind learns numerical and emotional relations and explores consequences for managerial and consumer decision making. First, we study how uncertainty in the environment affects covariation learning and explore the consequences for consumers’ price-quality inferences and product valuation. Secon...
Experimental and Numerical analysis of Metallic Bellow for Acoustic Performance
Panchwadkar, Amit A.; Awasare, Pradeep J., Dr.; Ingle, Ravidra B., Dr.
2017-08-01
Noise will concern about the work environment of industry. Machinery environment has overall noise which interrupts communication between the workers. This problem of miscommunication and health hazard will make sense to go for noise attenuation. Modification in machine setup may affect the performance of it. Instead of that, Helmholtz resonator principle will be a better option for noise reduction along the transmission path. Resonator has design variables which gives resonating frequency will help us to confirm the frequency range. This paper deals with metallic bellow which behaves like inertial mass under incident sound wave. Sound wave energy is affected by hard boundary condition of resonator and bellow. Metallic bellow is used in combination with resonator to find out Transmission loss (TL). Microphone attachment with FFT analyzer will give the frequency range for numerical analysis. Numerical analysis of bellow and resonator is carried out to summarize the acoustic behavior of bellow. Bellow can be numerically analyzed to check noise attenuation for centrifugal blower. An impedance tube measurement technique is performed to validate the numerical results for assembly. Dimensional and shape modification can be done to get the acoustic performance of bellow.
Numerical modeling of foam flows
International Nuclear Information System (INIS)
Cheddadi, Ibrahim
2010-01-01
Liquid foam flows are involved in numerous applications, e.g. food and cosmetics industries, oil extraction, nuclear decontamination. Moreover, their study leads to fundamental knowledge: as it is easier to manipulate and analyse, foam is used as a model material to understand the flow of emulsions, polymers, pastes, or cell aggregates, all of which display both solid and liquid behaviour. Systematic experiments performed by Francois Graner et al. provide precise data that emphasize the non Newtonian properties of the foam. Meanwhile, Pierre Saramito proposed a visco-elasto-plastic continuous tensorial model, akin to predict the behaviour of the foam. The goal of this thesis is to understand this complex behaviour, using these two elements. We have built and validated a resolution algorithm based on a bidimensional finite elements methods. The numerical solutions are in excellent agreement with the spatial distribution of all measured quantities, and confirm the predictive capabilities of the model. The dominant parameters have been identified and we evidenced the fact that the viscous, elastic, and plastic contributions to the flow have to be treated simultaneously in a tensorial formalism. We provide a substantial contribution to the understanding of foams and open the path to realistic simulations of complex VEP flows for industrial applications. (author)
Numerical Hydrodynamics in Special Relativity.
Martí, José Maria; Müller, Ewald
2003-01-01
This review is concerned with a discussion of numerical methods for the solution of the equations of special relativistic hydrodynamics (SRHD). Particular emphasis is put on a comprehensive review of the application of high-resolution shock-capturing methods in SRHD. Results of a set of demanding test bench simulations obtained with different numerical SRHD methods are compared. Three applications (astrophysical jets, gamma-ray bursts and heavy ion collisions) of relativistic flows are discussed. An evaluation of various SRHD methods is presented, and future developments in SRHD are analyzed involving extension to general relativistic hydrodynamics and relativistic magneto-hydrodynamics. The review further provides FORTRAN programs to compute the exact solution of a 1D relativistic Riemann problem with zero and nonzero tangential velocities, and to simulate 1D relativistic flows in Cartesian Eulerian coordinates using the exact SRHD Riemann solver and PPM reconstruction. Supplementary material is available for this article at 10.12942/lrr-2003-7 and is accessible for authorized users.
ENVIRONMENT AND PROTOSTELLAR EVOLUTION
Energy Technology Data Exchange (ETDEWEB)
Zhang, Yichen [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Tan, Jonathan C., E-mail: yczhang.astro@gmail.com [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
2015-04-01
Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of the resulting star and planetary systems. Here, we study the role of pressure, parameterized via ambient clump mass surface density, on protostellar evolution and appearance, focusing on low-mass Sun-like stars and considering a range of conditions from relatively low pressure filaments in Taurus, to intermediate pressures of cluster-forming clumps like the Orion Nebula Cluster, to very high pressures that may be found in the densest infrared dark clouds or in the Galactic center. We present unified analytic and numerical models for the collapse of prestellar cores, accretion disks, protostellar evolution, and bipolar outflows, coupled with radiative transfer calculations and a simple astrochemical model to predict CO gas-phase abundances. Prestellar cores in high-pressure environments are smaller and denser and thus collapse with higher accretion rates and efficiencies, resulting in higher luminosity protostars with more powerful outflows. The protostellar envelope is heated to warmer temperatures, affecting infrared morphologies (and thus classification) and astrochemical processes like CO depletion onto dust grain ice mantles (and thus CO morphologies). These results have general implications for star and planet formation, especially via their effect on astrochemical and dust grain evolution during infall to and through protostellar accretion disks.
Developing HYDMN code to include the transient of MNSR
International Nuclear Information System (INIS)
Al-Barhoum, M.
2000-11-01
A description of the programs added to HYDMN code (a code for thermal-hydraulic steady state of MNSR) to include the transient of the same MNSR is presented. The code asks the initial conditions for the power (in k W) and the cold initial core inlet temperature (in degrees centigrade). A time-dependent study of the coolant inlet and outlet temperature, its speed, pool and tank temperatures is done for MNSR in general and for the Syrian MNSR in particular. The study solves the differential equations taken from reference (1) by using some numerical methods found in reference (3). The code becomes this way independent of any external information source. (Author)
International Nuclear Information System (INIS)
Hargreaves, Anna L.; Whiteside, Douglas P.; Gilchrist, Grant
2011-01-01
Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential concern for breeding bird populations. - Highlights: → We assess elements in soil, invertebrates, and breeding shorebird tissues in the Arctic. → Element levels, invertebrate composition and shorebird use differed among habitat types. → Hg was elevated in blood and eggs and was negatively related to egg volume. → Hg and Se showed significant bioaccumulation and biomagnification. → However, all element levels were within available Canadian safety guidelines.
Energy Technology Data Exchange (ETDEWEB)
Hargreaves, Anna L., E-mail: alhargreaves@gmail.com [Calgary Zoo, Centre for Conservation Research, 1300 Zoo Rd NE, Calgary, AB, T2E 7V6 (Canada); Whiteside, Douglas P. [Calgary Zoo, Animal Health Centre, 1300 Zoo Rd NE, Calgary, AB, T2E 7V6 (Canada); University of Calgary, Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, 2500 University Dr. NW, Calgary, AB, T2N 1N4 (Canada); Gilchrist, Grant [Carleton University, National Wildlife Research Centre, Ottawa, ON, KIA OH3 (Canada)
2011-09-01
Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential concern for breeding bird populations. - Highlights: {yields} We assess elements in soil, invertebrates, and breeding shorebird tissues in the Arctic. {yields} Element levels, invertebrate composition and shorebird use differed among habitat types. {yields} Hg was elevated in blood and eggs and was negatively related to egg volume. {yields} Hg and Se showed significant bioaccumulation and biomagnification. {yields} However, all element levels were within available Canadian safety guidelines.
Hargreaves, Anna L; Whiteside, Douglas P; Gilchrist, Grant
2011-09-01
Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential concern for breeding bird populations. Copyright © 2011 Elsevier B.V. All rights reserved.
A systematic review including meta-analysis of work environment and burnout symptoms
Directory of Open Access Journals (Sweden)
Gunnar Aronsson
2017-03-01
Full Text Available Abstract Background Practitioners and decision makers in the medical and insurance systems need knowledge on the relationship between work exposures and burnout. Many burnout studies – original as well as reviews - restricted their analyses to emotional exhaustion or did not report results on cynicism, personal accomplishment or global burnout. To meet this need we carried out this review and meta-analyses with the aim to provide systematically graded evidence for associations between working conditions and near-future development of burnout symptoms. Methods A wide range of work exposure factors was screened. Inclusion criteria were: 1 Study performed in Europe, North America, Australia and New Zealand 1990–2013. 2 Prospective or comparable case control design. 3 Assessments of exposure (work and outcome at baseline and at least once again during follow up 1–5 years later. Twenty-five articles met the predefined relevance and quality criteria. The GRADE-system with its 4-grade evidence scale was used. Results Most of the 25 studies focused emotional exhaustion, fewer cynicism and still fewer personal accomplishment. Moderately strong evidence (grade 3 was concluded for the association between job control and reduced emotional exhaustion and between low workplace support and increased emotional exhaustion. Limited evidence (grade 2 was found for the associations between workplace justice, demands, high work load, low reward, low supervisor support, low co-worker support, job insecurity and change in emotional exhaustion. Cynicism was associated with most of these work factors. Reduced personal accomplishment was only associated with low reward. There were few prospective studies with sufficient quality on adverse chemical, biological and physical factors and burnout. Conclusion While high levels of job support and workplace justice were protective for emotional exhaustion, high demands, low job control, high work load, low reward and job insecurity increased the risk for developing exhaustion. Our approach with a wide range of work exposure factors analysed in relation to the separate dimensions of burnout expanded the knowledge of associations, evidence as well as research needs. The potential of organizational interventions is illustrated by the findings that burnout symptoms are strongly influenced by structural factors such as job demands, support and the possibility to exert control.
A systematic review including meta-analysis of work environment and burnout symptoms.
Aronsson, Gunnar; Theorell, Töres; Grape, Tom; Hammarström, Anne; Hogstedt, Christer; Marteinsdottir, Ina; Skoog, Ingmar; Träskman-Bendz, Lil; Hall, Charlotte
2017-03-16
Practitioners and decision makers in the medical and insurance systems need knowledge on the relationship between work exposures and burnout. Many burnout studies - original as well as reviews - restricted their analyses to emotional exhaustion or did not report results on cynicism, personal accomplishment or global burnout. To meet this need we carried out this review and meta-analyses with the aim to provide systematically graded evidence for associations between working conditions and near-future development of burnout symptoms. A wide range of work exposure factors was screened. Inclusion criteria were: 1) Study performed in Europe, North America, Australia and New Zealand 1990-2013. 2) Prospective or comparable case control design. 3) Assessments of exposure (work) and outcome at baseline and at least once again during follow up 1-5 years later. Twenty-five articles met the predefined relevance and quality criteria. The GRADE-system with its 4-grade evidence scale was used. Most of the 25 studies focused emotional exhaustion, fewer cynicism and still fewer personal accomplishment. Moderately strong evidence (grade 3) was concluded for the association between job control and reduced emotional exhaustion and between low workplace support and increased emotional exhaustion. Limited evidence (grade 2) was found for the associations between workplace justice, demands, high work load, low reward, low supervisor support, low co-worker support, job insecurity and change in emotional exhaustion. Cynicism was associated with most of these work factors. Reduced personal accomplishment was only associated with low reward. There were few prospective studies with sufficient quality on adverse chemical, biological and physical factors and burnout. While high levels of job support and workplace justice were protective for emotional exhaustion, high demands, low job control, high work load, low reward and job insecurity increased the risk for developing exhaustion. Our approach with a wide range of work exposure factors analysed in relation to the separate dimensions of burnout expanded the knowledge of associations, evidence as well as research needs. The potential of organizational interventions is illustrated by the findings that burnout symptoms are strongly influenced by structural factors such as job demands, support and the possibility to exert control.
Summary of research in applied mathematics, numerical analysis, and computer sciences
1986-01-01
The major categories of current ICASE research programs addressed include: numerical methods, with particular emphasis on the development and analysis of basic numerical algorithms; control and parameter identification problems, with emphasis on effective numerical methods; computational problems in engineering and physical sciences, particularly fluid dynamics, acoustics, and structural analysis; and computer systems and software, especially vector and parallel computers.
Directory of Open Access Journals (Sweden)
Zhou Yang
2017-01-01
Full Text Available High pressures, high speeds, low noise and miniaturization is the direction of development in hydraulic pump. According to the development trend, an operating helical rotor pump (HRP at high speeds and high pressures has been designed and produced, which rotational speed can reach 12000r/min and outlet pressure is as high as 25MPa. Three-dimensional simulation with and without cavitation inside the HRP is completed by the means of the computational fluid dynamics (CFD in this paper, which contributes to understand the complex fluid flow inside it. Moreover, the influences of the rotational speeds of the HRP with and without cavitation has been simulated at 25MPa.
Coupled numerical simulation of fire in tunnel
Pesavento, F.; Pachera, M.; Schrefler, B. A.; Gawin, D.; Witek, A.
2018-01-01
In this work, a coupling strategy for the analysis of a tunnel under fire is presented. This strategy consists in a "one-way" coupling between a tool considering the computational fluid dynamics and radiation with a model treating concrete as a multiphase porous material exposed to high temperature. This global approach allows for taking into account in a realistic manner the behavior of the "system tunnel", composed of the fluid and the solid domain (i.e. the concrete structures), from the fire onset, its development and propagation to the response of the structure. The thermal loads as well as the moisture exchange between the structure surface and the environment are calculated by means of computational fluid dynamics. These set of data are passed in an automatic way to the numerical tool implementing a model based on Multiphase Porous Media Mechanics. Thanks to this strategy the structural verification is no longer based on the standard fire curves commonly used in the engineering practice, but it is directly related to a realistic fire scenario. To show the capability of this strategy some numerical simulations of a fire in the Brenner Base Tunnel, under construction between Italy and Austria, is presented. The numerical simulations show the effects of a more realistic distribution of the thermal loads with respect to the ones obtained by using the standard fire curves. Moreover, it is possible to highlight how the localized thermal load generates a non-uniform pressure rise in the material, which results in an increase of the structure stress state and of the spalling risk. Spalling is likely the most dangerous collapse mechanism for a concrete structure. This coupling approach still represents a "one way" strategy, i.e. realized without considering explicitly the mass and energy exchange from the structure to the fluid through the interface. This results in an approximation, but from physical point of view the current form of the solid-fluid coupling is
Radiation and nuclear safety included in the environmental health programme
International Nuclear Information System (INIS)
Salomaa, S.
1996-01-01
Finland is currently preparing a national environmental health programme, the objective of which is to chart the main environmental health problems in Finland, to identify means for securing a healthy environment, and to draw up a practical action programme for preventing and rectifying problems pertaining to environmental health. Radiation and nuclear safety form an essential part of preventive health care. The action programme is based on decisions and programmes approved at the WHO Conference on the Environment and Health, held in Helsinki in June 1994. In addition to the state of the Finnish environment and the health of the Finnish population, the programme addresses the relevant international issues, in particular in areas adjacent to Finland. The Committee on Environmental Health is expected to complete its work by the end of the year. A wide range of representatives from various branches of administration have contributed to the preparation of the programme. Besides physical, biological and chemical factors, the environmental factors affecting health also include the physical environment and the psychological, social and aesthetic features of the environment. Similarly, environmental factors that have an impact on the health of present or future generations, on the essential preconditions of life and on the quality of life are investigated. The serious risk to nature caused by human actions is also considered as a potential risk to human health. (orig.)
Zhang, Junbiao
2001-10-01
Handheld devices are gaining great popularity and becoming a common commodity on the market primarily due to their small sizes and mobile nature. However, these devices are all limited in capabilities, especially in terms of screen display, processing power, storage space and network access. Some of these limitations, such as the small screen sizes, are inherently difficult to improve given the usage model of these devices. In this paper, we propose a framework in which small handheld devices can use their environment, the devices around them, to expand their limited capabilities. Such an environment can be deployed in the office, at home for user convenience or in a public access area as a revenue generating service. A handheld device interacts with the helper environment through several essential steps including device discovery, service query, request transfer and remote control. In order to ensure the proper operation of such an environment, the framework provides essential system components for admission control, resource allocation, task scheduling and device coordination. We refer to such a framework as the device helper environment and discuss its system architecture and usage scenarios in this paper.
Numerical modeling of exciton-polariton Bose-Einstein condensate in a microcavity
Voronych, Oksana; Buraczewski, Adam; Matuszewski, Michał; Stobińska, Magdalena
2017-06-01
A novel, optimized numerical method of modeling of an exciton-polariton superfluid in a semiconductor microcavity was proposed. Exciton-polaritons are spin-carrying quasiparticles formed from photons strongly coupled to excitons. They possess unique properties, interesting from the point of view of fundamental research as well as numerous potential applications. However, their numerical modeling is challenging due to the structure of nonlinear differential equations describing their evolution. In this paper, we propose to solve the equations with a modified Runge-Kutta method of 4th order, further optimized for efficient computations. The algorithms were implemented in form of C++ programs fitted for parallel environments and utilizing vector instructions. The programs form the EPCGP suite which has been used for theoretical investigation of exciton-polaritons. Catalogue identifier: AFBQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: BSD-3 No. of lines in distributed program, including test data, etc.: 2157 No. of bytes in distributed program, including test data, etc.: 498994 Distribution format: tar.gz Programming language: C++ with OpenMP extensions (main numerical program), Python (helper scripts). Computer: Modern PC (tested on AMD and Intel processors), HP BL2x220. Operating system: Unix/Linux and Windows. Has the code been vectorized or parallelized?: Yes (OpenMP) RAM: 200 MB for single run Classification: 7, 7.7. Nature of problem: An exciton-polariton superfluid is a novel, interesting physical system allowing investigation of high temperature Bose-Einstein condensation of exciton-polaritons-quasiparticles carrying spin. They have brought a lot of attention due to their unique properties and potential applications in polariton-based optoelectronic integrated circuits. This is an out-of-equilibrium quantum system confined
Development of a numerical pump testing framework.
Kaufmann, Tim A S; Gregory, Shaun D; Büsen, Martin R; Tansley, Geoff D; Steinseifer, Ulrich
2014-09-01
It has been shown that left ventricular assist devices (LVADs) increase the survival rate in end-stage heart failure patients. However, there is an ongoing demand for an increased quality of life, fewer adverse events, and more physiological devices. These challenges necessitate new approaches during the design process. In this study, computational fluid dynamics (CFD), lumped parameter (LP) modeling, mock circulatory loops (MCLs), and particle image velocimetry (PIV) are combined to develop a numerical Pump Testing Framework (nPTF) capable of analyzing local flow patterns and the systemic response of LVADs. The nPTF was created by connecting a CFD model of the aortic arch, including an LVAD outflow graft to an LP model of the circulatory system. Based on the same geometry, a three-dimensional silicone model was crafted using rapid prototyping and connected to an MCL. PIV studies of this setup were performed to validate the local flow fields (PIV) and the systemic response (MCL) of the nPTF. After validation, different outflow graft positions were compared using the nPTF. Both the numerical and the experimental setup were able to generate physiological responses by adjusting resistances and systemic compliance, with mean aortic pressures of 72.2-132.6 mm Hg for rotational speeds of 2200-3050 rpm. During LVAD support, an average flow to the distal branches (cerebral and subclavian) of 24% was found in the experiments and the nPTF. The flow fields from PIV and CFD were in good agreement. Numerical and experimental tools were combined to develop and validate the nPTF, which can be used to analyze local flow fields and the systemic response of LVADs during the design process. This allows analysis of physiological control parameters at early development stages and may, therefore, help to improve patient outcomes. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
42 CFR 410.100 - Included services.
2010-10-01
... service; however, maintenance therapy itself is not covered as part of these services. (c) Occupational... increase respiratory function, such as graded activity services; these services include physiologic... rehabilitation plan of treatment, including physical therapy services, occupational therapy services, speech...
Static, Lightweight Includes Resolution for PHP
M.A. Hills (Mark); P. Klint (Paul); J.J. Vinju (Jurgen)
2014-01-01
htmlabstractDynamic languages include a number of features that are challenging to model properly in static analysis tools. In PHP, one of these features is the include expression, where an arbitrary expression provides the path of the file to include at runtime. In this paper we present two
Article Including Environmental Barrier Coating System
Lee, Kang N. (Inventor)
2015-01-01
An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.
Rare thoracic cancers, including peritoneum mesothelioma
Siesling, Sabine; van der Zwan, Jan Maarten; Izarzugaza, Isabel; Jaal, Jana; Treasure, Tom; Foschi, Roberto; Ricardi, Umberto; Groen, Harry; Tavilla, Andrea; Ardanaz, Eva
Rare thoracic cancers include those of the trachea, thymus and mesothelioma (including peritoneum mesothelioma). The aim of this study was to describe the incidence, prevalence and survival of rare thoracic tumours using a large database, which includes cancer patients diagnosed from 1978 to 2002,
Rare thoracic cancers, including peritoneum mesothelioma
Siesling, Sabine; Zwan, J.M.V.D.; Izarzugaza, I.; Jaal, J.; Treasure, T.; Foschi, R.; Ricardi, U.; Groen, H.; Tavilla, A.; Ardanaz, E.
2012-01-01
Rare thoracic cancers include those of the trachea, thymus and mesothelioma (including peritoneum mesothelioma). The aim of this study was to describe the incidence, prevalence and survival of rare thoracic tumours using a large database, which includes cancer patients diagnosed from 1978 to 2002,
Numerical methods for Bayesian inference in the face of aging
International Nuclear Information System (INIS)
Clarotti, C.A.; Villain, B.; Procaccia, H.
1996-01-01
In recent years, much attention has been paid to Bayesian methods for Risk Assessment. Until now, these methods have been studied from a theoretical point of view. Researchers have been mainly interested in: studying the effectiveness of Bayesian methods in handling rare events; debating about the problem of priors and other philosophical issues. An aspect central to the Bayesian approach is numerical computation because any safety/reliability problem, in a Bayesian frame, ends with a problem of numerical integration. This aspect has been neglected until now because most Risk studies assumed the Exponential model as the basic probabilistic model. The existence of conjugate priors makes numerical integration unnecessary in this case. If aging is to be taken into account, no conjugate family is available and the use of numerical integration becomes compulsory. EDF (National Board of Electricity, of France) and ENEA (National Committee for Energy, New Technologies and Environment, of Italy) jointly carried out a research program aimed at developing quadrature methods suitable for Bayesian Interference with underlying Weibull or gamma distributions. The paper will illustrate the main results achieved during the above research program and will discuss, via some sample cases, the performances of the numerical algorithms which on the appearance of stress corrosion cracking in the tubes of Steam Generators of PWR French power plants. (authors)
Numerical modelling of river morphodynamics: Latest developments and remaining challenges
Siviglia, Annunziato; Crosato, Alessandra
2016-07-01
Numerical morphodynamic models provide scientific frameworks for advancing our understanding of river systems. The research on involved topics is an important and socially relevant undertaking regarding our environment. Nowadays numerical models are used for different purposes, from answering questions about basic morphodynamic research to managing complex river engineering problems. Due to increasing computer power and the development of advanced numerical techniques, morphodynamic models are now more and more used to predict the bed patterns evolution to a broad spectrum of spatial and temporal scales. The development and the success of application of such models are based upon a wide range of disciplines from applied mathematics for the numerical solution of the equations to geomorphology for the physical interpretation of the results. In this light we organized this special issue (SI) soliciting multidisciplinary contributions which encompass any aspect needed for the development and applications of such models. Most of the papers in the SI stem from contributions to session HS9.5/GM7.11 on numerical modelling and experiments in river morphodynamics at the European Geosciences Union (EGU) General Assembly held in Vienna, April 27th to May 2nd 2014.
Cone Algorithm of Spinning Vehicles under Dynamic Coning Environment
Directory of Open Access Journals (Sweden)
Shuang-biao Zhang
2015-01-01
Full Text Available Due to the fact that attitude error of vehicles has an intense trend of divergence when vehicles undergo worsening coning environment, in this paper, the model of dynamic coning environment is derived firstly. Then, through investigation of the effect on Euler attitude algorithm for the equivalency of traditional attitude algorithm, it is found that attitude error is actually the roll angle error including drifting error and oscillating error, which is induced directly by dynamic coning environment and further affects the pitch angle and yaw angle through transferring. Based on definition of the cone frame and cone attitude, a cone algorithm is proposed by rotation relationship to calculate cone attitude, and the relationship between cone attitude and Euler attitude of spinning vehicle is established. Through numerical simulations with different conditions of dynamic coning environment, it is shown that the induced error of Euler attitude fluctuates by the variation of precession and nutation, especially by that of nutation, and the oscillating frequency of roll angle error is twice that of pitch angle error and yaw angle error. In addition, the rotation angle is more competent to describe the spinning process of vehicles under coning environment than Euler angle gamma, and the real pitch angle and yaw angle are calculated finally.
Numerical model of thyroid counter
Directory of Open Access Journals (Sweden)
Szuchta Maciej
2016-03-01
Full Text Available The aim of this study was to develop a numerical model of spectrometric thyroid counter, which is used for the measurements of internal contamination by in vivo method. The modeled detector is used for a routine internal exposure monitoring procedure in the Radiation Protection Measurements Laboratory of National Centre for Nuclear Research (NCBJ. This procedure may also be used for monitoring of occupationally exposed nuclear medicine personnel. The developed model was prepared using Monte Carlo code FLUKA 2011 ver. 2b.6 Apr-14 and FLAIR ver. 1.2-5 interface. It contains a scintillation NaI(Tl detector, the collimator and the thyroid water phantom with a reference source of iodine 131I. The geometry of the model was designed and a gamma energy spectrum of iodine 131I deposited in the detector was calculated.
Numerical methods used in simulation
International Nuclear Information System (INIS)
Caseau, Paul; Perrin, Michel; Planchard, Jacques
1978-01-01
The fundamental numerical problem posed by simulation problems is the stability of the resolution diagram. The system of the most used equations is defined, since there is a family of models of increasing complexity with 3, 4 or 5 equations although only models with 3 and 4 equations have been used extensively. After defining what is meant by explicit or implicit, the best established stability results is given for one-dimension problems and then for two-dimension problems. It is shown that two types of discretisation may be defined: four and eight point diagrams (in one or two dimensions) and six and ten point diagrams (in one or two dimensions). To end, some results are given on problems that are not usually treated very much, i.e. non-asymptotic stability and the stability of diagrams based on finite elements [fr
Numerical optimization using flow equations
Punk, Matthias
2014-12-01
We develop a method for multidimensional optimization using flow equations. This method is based on homotopy continuation in combination with a maximum entropy approach. Extrema of the optimizing functional correspond to fixed points of the flow equation. While ideas based on Bayesian inference such as the maximum entropy method always depend on a prior probability, the additional step in our approach is to perform a continuous update of the prior during the homotopy flow. The prior probability thus enters the flow equation only as an initial condition. We demonstrate the applicability of this optimization method for two paradigmatic problems in theoretical condensed matter physics: numerical analytic continuation from imaginary to real frequencies and finding (variational) ground states of frustrated (quantum) Ising models with random or long-range antiferromagnetic interactions.
Strongly correlated systems numerical methods
Mancini, Ferdinando
2013-01-01
This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...
Automatic validation of numerical solutions
DEFF Research Database (Denmark)
Stauning, Ole
1997-01-01
This thesis is concerned with ``Automatic Validation of Numerical Solutions''. The basic theory of interval analysis and self-validating methods is introduced. The mean value enclosure is applied to discrete mappings for obtaining narrow enclosures of the iterates when applying these mappings...... differential equations, but in this thesis, we describe how to use the methods for enclosing iterates of discrete mappings, and then later use them for discretizing solutions of ordinary differential equations. The theory of automatic differentiation is introduced, and three methods for obtaining derivatives...... are described: The forward, the backward, and the Taylor expansion methods. The three methods have been implemented in the C++ program packages FADBAD/TADIFF. Some examples showing how to use the three metho ds are presented. A feature of FADBAD/TADIFF not present in other automatic differentiation packages...
Operator theory and numerical methods
Fujita, H; Suzuki, T
2001-01-01
In accordance with the developments in computation, theoretical studies on numerical schemes are now fruitful and highly needed. In 1991 an article on the finite element method applied to evolutionary problems was published. Following the method, basically this book studies various schemes from operator theoretical points of view. Many parts are devoted to the finite element method, but other schemes and problems (charge simulation method, domain decomposition method, nonlinear problems, and so forth) are also discussed, motivated by the observation that practically useful schemes have fine mathematical structures and the converses are also true. This book has the following chapters: 1. Boundary Value Problems and FEM. 2. Semigroup Theory and FEM. 3. Evolution Equations and FEM. 4. Other Methods in Time Discretization. 5. Other Methods in Space Discretization. 6. Nonlinear Problems. 7. Domain Decomposition Method.
Plasma modelling and numerical simulation
International Nuclear Information System (INIS)
Van Dijk, J; Kroesen, G M W; Bogaerts, A
2009-01-01
Plasma modelling is an exciting subject in which virtually all physical disciplines are represented. Plasma models combine the electromagnetic, statistical and fluid dynamical theories that have their roots in the 19th century with the modern insights concerning the structure of matter that were developed throughout the 20th century. The present cluster issue consists of 20 invited contributions, which are representative of the state of the art in plasma modelling and numerical simulation. These contributions provide an in-depth discussion of the major theories and modelling and simulation strategies, and their applications to contemporary plasma-based technologies. In this editorial review, we introduce and complement those papers by providing a bird's eye perspective on plasma modelling and discussing the historical context in which it has surfaced. (editorial review)
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)
Numerical evidence for 'multiscalar stars'
International Nuclear Information System (INIS)
Hawley, Scott H.; Choptuik, Matthew W.
2003-01-01
We present a class of general relativistic solitonlike solutions composed of multiple minimally coupled, massive, real scalar fields which interact only through the gravitational field. We describe a two-parameter family of solutions we call ''phase-shifted boson stars'' (parametrized by central density ρ 0 and phase δ), which are obtained by solving the ordinary differential equations associated with boson stars and then altering the phase between the real and imaginary parts of the field. These solutions are similar to boson stars as well as the oscillating soliton stars found by Seidel and Suen [E. Seidel and W. M. Suen, Phys. Rev. Lett. 66, 1659 (1991)]; in particular, long-time numerical evolutions suggest that phase-shifted boson stars are stable. Our results indicate that scalar solitonlike solutions are perhaps more generic than has been previously thought
Combining Narrative and Numerical Simulation
DEFF Research Database (Denmark)
Hansen, Mette Sanne; Ladeby, Klaes Rohde; Rasmussen, Lauge Baungaard
2011-01-01
for decision makers to systematically test several different outputs of possible solutions in order to prepare for future consequences. The CSA can be a way to evaluate risks and address possible unforeseen problems in a more methodical way than either guessing or forecasting. This paper contributes...... to the decision making in operations and production management by providing new insights into modelling and simulation based on the combined narrative and numerical simulation approach as a tool for strategy making. The research question asks, “How can the CSA be applied in a practical context to support strategy...... making?” The paper uses a case study where interviews and observations were carried out in a Danish corporation. The CSA is a new way to address decision making and has both practical value and further expands the use of strategic simulation as a management tool....
Numerical methods design, analysis, and computer implementation of algorithms
Greenbaum, Anne
2012-01-01
Numerical Methods provides a clear and concise exploration of standard numerical analysis topics, as well as nontraditional ones, including mathematical modeling, Monte Carlo methods, Markov chains, and fractals. Filled with appealing examples that will motivate students, the textbook considers modern application areas, such as information retrieval and animation, and classical topics from physics and engineering. Exercises use MATLAB and promote understanding of computational results. The book gives instructors the flexibility to emphasize different aspects--design, analysis, or computer implementation--of numerical algorithms, depending on the background and interests of students. Designed for upper-division undergraduates in mathematics or computer science classes, the textbook assumes that students have prior knowledge of linear algebra and calculus, although these topics are reviewed in the text. Short discussions of the history of numerical methods are interspersed throughout the chapters. The book a...
A numerical library in Java for scientists and engineers
Lau, Hang T
2003-01-01
At last researchers have an inexpensive library of Java-based numeric procedures for use in scientific computation. The first and only book of its kind, A Numeric Library in Java for Scientists and Engineers is a translation into Java of the library NUMAL (NUMerical procedures in ALgol 60). This groundbreaking text presents procedural descriptions for linear algebra, ordinary and partial differential equations, optimization, parameter estimation, mathematical physics, and other tools that are indispensable to any dynamic research group. The book offers test programs that allow researchers to execute the examples provided; users are free to construct their own tests and apply the numeric procedures to them in order to observe a successful computation or simulate failure. The entry for each procedure is logically presented, with name, usage parameters, and Java code included. This handbook serves as a powerful research tool, enabling the performance of critical computations in Java. It stands as a cost-effi...
Numerical Modelling and Measurement in a Test Secondary Settling Tank
DEFF Research Database (Denmark)
Dahl, C.; Larsen, Torben; Petersen, O.
1994-01-01
sludge. Phenomena as free and hindered settling and the Bingham plastic characteristic of activated sludge suspensions are included in the numerical model. Further characterisation and test tank experiments are described. The characterisation experiments were designed to measure calibration parameters...... for model description of settling and density differences. In the test tank experiments, flow velocities and suspended sludge concentrations were measured with different tank inlet geomotry and hydraulic and sludge loads. The test tank experiments provided results for the calibration of the numerical model......A numerical model and measurements of flow and settling in activated sludge suspension is presented. The numerical model is an attempt to describe the complex and interrelated hydraulic and sedimentation phenomena by describing the turbulent flow field and the transport/dispersion of suspended...
Mathematical and numerical foundations of turbulence models and applications
Chacón Rebollo, Tomás
2014-01-01
With applications to climate, technology, and industry, the modeling and numerical simulation of turbulent flows are rich with history and modern relevance. The complexity of the problems that arise in the study of turbulence requires tools from various scientific disciplines, including mathematics, physics, engineering, and computer science. Authored by two experts in the area with a long history of collaboration, this monograph provides a current, detailed look at several turbulence models from both the theoretical and numerical perspectives. The k-epsilon, large-eddy simulation, and other models are rigorously derived and their performance is analyzed using benchmark simulations for real-world turbulent flows. Mathematical and Numerical Foundations of Turbulence Models and Applications is an ideal reference for students in applied mathematics and engineering, as well as researchers in mathematical and numerical fluid dynamics. It is also a valuable resource for advanced graduate students in fluid dynamics,...
Numerical Study on Critical Wedge Angle of Cellular Detonation Reflections
International Nuclear Information System (INIS)
Gang, Wang; Kai-Xin, Liu; De-Liang, Zhang
2010-01-01
The critical wedge angle (CWA) for the transition from regular reflection (RR) to Mach reflection (MR) of a cellular detonation wave is studied numerically by an improved space-time conservation element and solution element method together with a two-step chemical reaction model. The accuracy of that numerical way is verified by simulating cellular detonation reflections at a 19.3° wedge. The planar and cellular detonation reflections over 45°–55° wedges are also simulated. When the cellular detonation wave is over a 50° wedge, numerical results show a new phenomenon that RR and MR occur alternately. The transition process between RR and MR is investigated with the local pressure contours. Numerical analysis shows that the cellular structure is the essential reason for the new phenomenon and the CWA of detonation reflection is not a certain angle but an angle range. (fundamental areas of phenomenology(including applications))
Summary of Numerical Modeling for Underground Nuclear Test Monitoring Symposium
International Nuclear Information System (INIS)
Taylor, S.R.; Kamm, J.R.
1993-01-01
This document contains the Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium held in Durango, Colorado on March 23-25, 1993. The symposium was sponsored by the Office of Arms Control and Nonproliferation of the United States Department of Energy and hosted by the Source Region Program of Los Alamos National Laboratory. The purpose of the meeting was to discuss state-of-the-art advances in numerical simulations of nuclear explosion phenomenology for the purpose of test ban monitoring. Another goal of the symposium was to promote discussion between seismologists and explosion source-code calculators. Presentation topics include the following: numerical model fits to data, measurement and characterization of material response models, applications of modeling to monitoring problems, explosion source phenomenology, numerical simulations and seismic sources
NUMERICAL MODEL APPLICATION IN ROWING SIMULATOR DESIGN
Directory of Open Access Journals (Sweden)
Petr Chmátal
2016-04-01
Full Text Available The aim of the research was to carry out a hydraulic design of rowing/sculling and paddling simulator. Nowadays there are two main approaches in the simulator design. The first one includes a static water with no artificial movement and counts on specially cut oars to provide the same resistance in the water. The second approach, on the other hand uses pumps or similar devices to force the water to circulate but both of the designs share many problems. Such problems are affecting already built facilities and can be summarized as unrealistic feeling, unwanted turbulent flow and bad velocity profile. Therefore, the goal was to design a new rowing simulator that would provide nature-like conditions for the racers and provide an unmatched experience. In order to accomplish this challenge, it was decided to use in-depth numerical modeling to solve the hydraulic problems. The general measures for the design were taken in accordance with space availability of the simulator ́s housing. The entire research was coordinated with other stages of the construction using BIM. The detailed geometry was designed using a numerical model in Ansys Fluent and parametric auto-optimization tools which led to minimum negative hydraulic phenomena and decreased investment and operational costs due to the decreased hydraulic losses in the system.
The Beam Break-Up Numerical Simulator
International Nuclear Information System (INIS)
Travish, G.A.
1989-11-01
Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs
Abstract numerical discrimination learning in rats.
Taniuchi, Tohru; Sugihara, Junko; Wakashima, Mariko; Kamijo, Makiko
2016-06-01
In this study, we examined rats' discrimination learning of the numerical ordering positions of objects. In Experiments 1 and 2, five out of seven rats successfully learned to respond to the third of six identical objects in a row and showed reliable transfer of this discrimination to novel stimuli after being trained with three different training stimuli. In Experiment 3, the three rats from Experiment 2 continued to be trained to respond to the third object in an object array, which included an odd object that needed to be excluded when identifying the target third object. All three rats acquired this selective-counting task of specific stimuli, and two rats showed reliable transfer of this selective-counting performance to test sets of novel stimuli. In Experiment 4, the three rats from Experiment 3 quickly learned to respond to the third stimulus in object rows consisting of either six identical or six different objects. These results offer strong evidence for abstract numerical discrimination learning in rats.
Numerical calculation of two-phase flows
International Nuclear Information System (INIS)
Travis, J.R.; Harlow, F.H.; Amsden, A.A.
1975-06-01
The theoretical study of time-varying two-phase flow problems in several space dimensions introduces such a complicated set of coupled nonlinear partial differential equations that numerical solution procedures for high-speed computers are required in almost all but the simplest examples. Efficient attainment of realistic solutions for practical problems requires a finite- difference formulation that is simultaneously implicit in the treatment of mass convection, equations of state, and the momentum coupling between phases. Such a method is described, the equations on which it is based are discussed, and its properties are illustrated by means of examples. In particular, the capability for calculating physical instabilities and other time-varying dynamics, at the same time avoiding numerical instability is emphasized. The computer code is applicable to problems in reactor safety analysis, the dynamics of fluidized dust beds, raindrops or aerosol transport, and a variety of similar circumstances, including the effects of phase transitions and the release of latent heat or chemical energy. (U.S.)
Numerical Methods for Free Boundary Problems
1991-01-01
About 80 participants from 16 countries attended the Conference on Numerical Methods for Free Boundary Problems, held at the University of Jyviiskylii, Finland, July 23-27, 1990. The main purpose of this conference was to provide up-to-date information on important directions of research in the field of free boundary problems and their numerical solutions. The contributions contained in this volume cover the lectures given in the conference. The invited lectures were given by H.W. Alt, V. Barbu, K-H. Hoffmann, H. Mittelmann and V. Rivkind. In his lecture H.W. Alt considered a mathematical model and existence theory for non-isothermal phase separations in binary systems. The lecture of V. Barbu was on the approximate solvability of the inverse one phase Stefan problem. K-H. Hoff mann gave an up-to-date survey of several directions in free boundary problems and listed several applications, but the material of his lecture is not included in this proceedings. H.D. Mittelmann handled the stability of thermo capi...
Getting a Kick Out of Numerical Relativity
2006-01-01
Operating ground-based gravitational wave detectors and a planned instrument in space are bringing about the new field of gravitational wave astronomy. A prime source for any of these observatories is the merger of a system of two black holes. Brought together by copious losses of gravitational-wave energy, these systems merge in a burst of energy with a peak power exceeding any electromagnetic source. Observations of these sources will generate a wealth of astrophysical information, and may provide an unparalleled probe of strong-field gravitational physics, but a full interpretation of the observations will require detailed predictions from General Relativity. I will discuss recent advances in numerical simulations of binary black hole systems which are generating dramatic progress in understanding binary black hole mergers. Recent achievements include the first simulations of binary black hole systems through several orbits and merger, leading to detailed predictions for the final portion of the gravitational radiation waveforms from equal-mass mergers. For unequal-mass mergers, it has recently become possible to measure the impulsive kick imparted to the final black hole, by the asymmetry of the merger radiation. These first results announce an accelerating wave of progress soon to come from the energetic field of numerical relativity.
A numerical model of heavy gas dispersion
International Nuclear Information System (INIS)
Bidokhtti, A.A.
1993-01-01
A simple mathematical model describing the motion of a dense gas released continuously into and environment is presented. The model correctly predicts the laboratory experiments which were carried out by Britter and Snyder (1987). It is an entrainment model better known as box model. In this model, the effects of temperature change and phase change are not considered and it is for a steady-state case. Further work is required for including these effects which are often associated with the mechanisms involved in accidental or natural release of heavy gases in the environment. The results of such a model will be extended to the practical situations which are and will be common to the nuclear industry at the Atomic Energy Organization of Iran. The applicability of such studies to these situations will be discussed
Advanced Numerical Model for Irradiated Concrete
Energy Technology Data Exchange (ETDEWEB)
Giorla, Alain B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2015-03-01
In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some
Numerical prediction of shoreline adjacent to breakwater
Digital Repository Service at National Institute of Oceanography (India)
Mahadevan, R.; Chandramohan, P.; Nayak, B.U.
Existing mathematical models for prediction of shoreline changes in the vicinity of a breakwater were reviewed The analytical and numerical results obtained from these models have been compared Under the numerical approach, two different implicit...
Non-human C. difficile Reservoirs and Sources: Animals, Food, Environment.
Rodriguez Diaz, Cristina; Seyboldt, Christian; Rupnik, Maja
2018-01-01
Clostridium difficile is ubiquitous and is found in humans, animals and in variety of environments. The substantial overlap of ribotypes between all three main reservoirs suggests the extensive transmissions. Here we give the overview of European studies investigating farm, companion and wild animals, food and environments including water, soil, sediment, waste water treatment plants, biogas plants, air and households. Studies in Europe are more numerous especially in last couple of years, but are still fragmented in terms of countries, animal species or type of environment covered. Soil seem to be the habitat of divergent unusual lineages of C. difficile. But the most important aspect of animals and environment is their role in C. difficile transmissions and their potential as a source for human infection is discussed.
Dust in cosmic plasma environments
International Nuclear Information System (INIS)
Mendis, D.A.
1979-01-01
Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments - including planetary magnetospheres, the heliosphere and the interstellar medium - are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed. (Auth.)
Numerical Methods in Atmospheric and Oceanic Modelling: The Andre J. Robert Memorial Volume
Rosmond, Tom
Most people, even including some in the scientific community, do not realize how much the weather forecasts they use to guide the activities of their daily lives depend on very complex mathematics and numerical methods that are the basis of modern numerical weather prediction (NWP). André Robert (1929-1993), to whom Numerical Methods in Atmospheric and Oceanic Modelling is dedicated, had a career that contributed greatly to the growth of NWP and the role that the atmospheric computer models of NWP play in our society. There are probably no NWP models running anywhere in the world today that do not use numerical methods introduced by Robert, and those of us who work with and use these models everyday are indebted to him.The first two chapters of the volume are chronicles of Robert's life and career. The first is a 1987 interview by Harold Ritchie, one of Robert's many proteges and colleagues at the Canadian Atmospheric Environment Service. The interview traces Robert's life from his birth in New York to French Canadian parents, to his emigration to Quebec at an early age, his education and early employment, and his rise in stature as one of the preeminent research meteorologists of our time. An amusing anecdote he relates is his impression of weather forecasts while he was considering his first job as a meteorologist in the early 1950s. A newspaper of the time placed the weather forecast and daily horoscope side by side, and Robert regarded each to have a similar scientific basis. Thankfully he soon realized there was a difference between the two, and his subsequent career certainly confirmed the distinction.
Designing for the global environment
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-12-31
This document contains papers which were presented at the symposium entitled Designing for the Global Environment. Session topics included policy and the implementation of energy efficient technologies. Individual papers were processed separately for the Department of Energy databases.
NINJA: Java for High Performance Numerical Computing
Directory of Open Access Journals (Sweden)
José E. Moreira
2002-01-01
Full Text Available When Java was first introduced, there was a perception that its many benefits came at a significant performance cost. In the particularly performance-sensitive field of numerical computing, initial measurements indicated a hundred-fold performance disadvantage between Java and more established languages such as Fortran and C. Although much progress has been made, and Java now can be competitive with C/C++ in many important situations, significant performance challenges remain. Existing Java virtual machines are not yet capable of performing the advanced loop transformations and automatic parallelization that are now common in state-of-the-art Fortran compilers. Java also has difficulties in implementing complex arithmetic efficiently. These performance deficiencies can be attacked with a combination of class libraries (packages, in Java that implement truly multidimensional arrays and complex numbers, and new compiler techniques that exploit the properties of these class libraries to enable other, more conventional, optimizations. Two compiler techniques, versioning and semantic expansion, can be leveraged to allow fully automatic optimization and parallelization of Java code. Our measurements with the NINJA prototype Java environment show that Java can be competitive in performance with highly optimized and tuned Fortran code.
Kaplan, Michael L.; Lux, Kevin M.; Cetola, Jeffrey D.; Huffman, Allan W.; Riordan, Allen J.; Slusser, Sarah W.; Lin, Yuh-Lang; Charney, Joseph J.; Waight, Kenneth T.
2004-01-01
Real-time prediction of environments predisposed to producing moderate-severe aviation turbulence is studied. We describe the numerical model and its postprocessing system designed for said prediction of environments predisposed to severe aviation turbulence as well as presenting numerous examples of its utility. The numerical model is MASS version 5.13, which is integrated over three different grid matrices in real time on a university work station in support of NASA Langley Research Center s B-757 turbulence research flight missions. The postprocessing system includes several turbulence-related products, including four turbulence forecasting indices, winds, streamlines, turbulence kinetic energy, and Richardson numbers. Additionally, there are convective products including precipitation, cloud height, cloud mass fluxes, lifted index, and K-index. Furthermore, soundings, sounding parameters, and Froude number plots are also provided. The horizontal cross-section plot products are provided from 16 000 to 46 000 ft in 2000-ft intervals. Products are available every 3 hours at the 60- and 30-km grid interval and every 1.5 hours at the 15-km grid interval. The model is initialized from the NWS ETA analyses and integrated two times a day.
Applications of granular-dynamics numerical simulations to asteroid surfaces
Richardson, D. C.; Michel, P.; Schwartz, S. R.; Yu, Y.; Ballouz, R.-L.; Matsumura, S.
2014-07-01
Spacecraft images and indirect observations including thermal inertia measurements indicate most small bodies have surface regolith. Evidence of granular flow is also apparent in the images. This material motion occurs in very low gravity, therefore in a totally different gravitational environment than on the Earth. Upcoming sample-return missions to small bodies, and possible future manned missions, will involve interaction with the surface regolith, so it is important to develop tools to predict the surface response. We have added new capabilities to the N-body gravity tree code pkdgrav [1,2] that permit the simulation of granular dynamics, including multi-contact physics and friction forces, using the soft-sphere discrete-element method [3]. The numerical approach has been validated through comparison with laboratory experiments (e.g., [3,4]). (1) We carried out impacts into granular materials using different projectile shapes under Earth's gravity [5] and compared the results to laboratory experiments [6] in support of JAXA's Hayabusa 2 asteroid sample-return mission. We tested different projectile shapes and confirmed that the 90-degree cone was the most efficient at excavating mass when impacting 5-mm-diameter glass beads. Results are sensitive to the normal coefficient of restitution and the coefficient of static friction. Preliminary experiments in micro-gravity for similar impact conditions show both the amount of ejected mass and the timescale of the impact process increase, as expected. (2) It has been found (e.g., [7,8]) that ''fresh'' (unreddened) Q-class asteroids have a high probability of recent planetary encounters (˜1 Myr; also see [9]), suggesting that surface refreshening may have occurred due to tidal effects. As an application of the potential effect of tidal interactions, we carried out simulations of Apophis' predicted 2029 encounter with the Earth to see whether regolith motion might occur, using a range of plausible material parameters
Katsaounis, T. D.
2005-02-01
The scope of this book is to present well known simple and advanced numerical methods for solving partial differential equations (PDEs) and how to implement these methods using the programming environment of the software package Diffpack. A basic background in PDEs and numerical methods is required by the potential reader. Further, a basic knowledge of the finite element method and its implementation in one and two space dimensions is required. The authors claim that no prior knowledge of the package Diffpack is required, which is true, but the reader should be at least familiar with an object oriented programming language like C++ in order to better comprehend the programming environment of Diffpack. Certainly, a prior knowledge or usage of Diffpack would be a great advantage to the reader. The book consists of 15 chapters, each one written by one or more authors. Each chapter is basically divided into two parts: the first part is about mathematical models described by PDEs and numerical methods to solve these models and the second part describes how to implement the numerical methods using the programming environment of Diffpack. Each chapter closes with a list of references on its subject. The first nine chapters cover well known numerical methods for solving the basic types of PDEs. Further, programming techniques on the serial as well as on the parallel implementation of numerical methods are also included in these chapters. The last five chapters are dedicated to applications, modelled by PDEs, in a variety of fields. The first chapter is an introduction to parallel processing. It covers fundamentals of parallel processing in a simple and concrete way and no prior knowledge of the subject is required. Examples of parallel implementation of basic linear algebra operations are presented using the Message Passing Interface (MPI) programming environment. Here, some knowledge of MPI routines is required by the reader. Examples solving in parallel simple PDEs using
Numerical analysis of the performance prediction for a thermoelectric generator
Energy Technology Data Exchange (ETDEWEB)
Kim, Chang Nyung [Kyung Hee University, Yongin (Korea, Republic of)
2015-09-15
The present study develops a two-dimensional numerical code that can predict the performance of a thermoelectric generator module including a p-leg/n-leg pair and top and bottom electrodes. The present code can simulate the detailed thermoelectric phenomena including the heat flow, electric current, Joule heating, Peltier heating, and Thomson heating, together with the efficiency of the modules whose properties depend on the temperature. The present numerical code can be used for the design optimization of a thermoelectric power generator.
Interagency mechanical operations group numerical systems group
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-09-01
This report consists of the minutes of the May 20-21, 1971 meeting of the Interagency Mechanical Operations Group (IMOG) Numerical Systems Group. This group looks at issues related to numerical control in the machining industry. Items discussed related to the use of CAD and CAM, EIA standards, data links, and numerical control.
XFEL OSCILLATOR SIMULATION INCLUDING ANGLE-DEPENDENT CRYSTAL REFLECTIVITY
International Nuclear Information System (INIS)
Fawley, William; Lindberg, Ryan; Kim, K.-J.; Shvyd'ko, Yuri
2010-01-01
The oscillator package within the GINGER FEL simulation code has now been extended to include angle-dependent reflectivity properties of Bragg crystals. Previously, the package was modified to include frequencydependent reflectivity in order to model x-ray FEL oscillators from start-up from shot noise through to saturation. We present a summary of the algorithms used for modeling the crystal reflectivity and radiation propagation outside the undulator, discussing various numerical issues relevant to the domain of high Fresnel number and efficient Hankel transforms. We give some sample XFEL-O simulation results obtained with the angle-dependent reflectivity model, with particular attention directed to the longitudinal and transverse coherence of the radiation output.
Seepage Model for PA Including Drift Collapse
International Nuclear Information System (INIS)
Li, G.; Tsang, C.
2000-01-01
The purpose of this Analysis/Model Report (AMR) is to document the predictions and analysis performed using the Seepage Model for Performance Assessment (PA) and the Disturbed Drift Seepage Submodel for both the Topopah Spring middle nonlithophysal and lower lithophysal lithostratigraphic units at Yucca Mountain. These results will be used by PA to develop the probability distribution of water seepage into waste-emplacement drifts at Yucca Mountain, Nevada, as part of the evaluation of the long term performance of the potential repository. This AMR is in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (CRWMS M andO 2000 [153447]). This purpose is accomplished by performing numerical simulations with stochastic representations of hydrological properties, using the Seepage Model for PA, and evaluating the effects of an alternative drift geometry representing a partially collapsed drift using the Disturbed Drift Seepage Submodel. Seepage of water into waste-emplacement drifts is considered one of the principal factors having the greatest impact of long-term safety of the repository system (CRWMS M andO 2000 [153225], Table 4-1). This AMR supports the analysis and simulation that are used by PA to develop the probability distribution of water seepage into drift, and is therefore a model of primary (Level 1) importance (AP-3.15Q, ''Managing Technical Product Inputs''). The intended purpose of the Seepage Model for PA is to support: (1) PA; (2) Abstraction of Drift-Scale Seepage; and (3) Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR). Seepage into drifts is evaluated by applying numerical models with stochastic representations of hydrological properties and performing flow simulations with multiple realizations of the permeability field around the drift. The Seepage Model for PA uses the distribution of permeabilities derived from air injection testing in niches and in the cross drift to
Seepage Model for PA Including Dift Collapse
Energy Technology Data Exchange (ETDEWEB)
G. Li; C. Tsang
2000-12-20
The purpose of this Analysis/Model Report (AMR) is to document the predictions and analysis performed using the Seepage Model for Performance Assessment (PA) and the Disturbed Drift Seepage Submodel for both the Topopah Spring middle nonlithophysal and lower lithophysal lithostratigraphic units at Yucca Mountain. These results will be used by PA to develop the probability distribution of water seepage into waste-emplacement drifts at Yucca Mountain, Nevada, as part of the evaluation of the long term performance of the potential repository. This AMR is in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (CRWMS M&O 2000 [153447]). This purpose is accomplished by performing numerical simulations with stochastic representations of hydrological properties, using the Seepage Model for PA, and evaluating the effects of an alternative drift geometry representing a partially collapsed drift using the Disturbed Drift Seepage Submodel. Seepage of water into waste-emplacement drifts is considered one of the principal factors having the greatest impact of long-term safety of the repository system (CRWMS M&O 2000 [153225], Table 4-1). This AMR supports the analysis and simulation that are used by PA to develop the probability distribution of water seepage into drift, and is therefore a model of primary (Level 1) importance (AP-3.15Q, ''Managing Technical Product Inputs''). The intended purpose of the Seepage Model for PA is to support: (1) PA; (2) Abstraction of Drift-Scale Seepage; and (3) Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR). Seepage into drifts is evaluated by applying numerical models with stochastic representations of hydrological properties and performing flow simulations with multiple realizations of the permeability field around the drift. The Seepage Model for PA uses the distribution of permeabilities derived from air injection testing in
Numerical simulation of heterogeneous phase transformations
International Nuclear Information System (INIS)
Combeau, H.; Lacaze, J.
1993-01-01
A numerical model is presented for the simulation of diffusion controlled phase transformations in multicomponent alloys. A closed system is considered, with simple geometric shape, either planar, cylindrical or spherical. The temperature inside this microscopic volume is homogeneous, but can vary according to any specified monoteneous law. Particular care has been given to the description of the solute profiles where the concentration gradients are the steepest, i.e. near the interface between the parent and the resultant phases. Solute redistribution at the interface is described by means of an original method which ensures that the overall solute balance is satisfied. A non linear system is obtained which includes the diffusion equations in both phases and the boundary conditions. The solution of this system makes use of a special algorithm which has been devised for a quick convergence. An example is presented which deals with microsegregation build-up during solidification of a multi-component nickel base alloy. (orig.)
Numerical cosmology: Revealing the universe using computers
International Nuclear Information System (INIS)
Centrella, J.; Matzner, R.A.; Tolman, B.W.
1986-01-01
In this paper the authors present two research projects which study the evolution of different periods in the history of the universe using numerical simulations. The first investigates the synthesis of light elements in an inhomogeneous early universe dominated by shocks and non-linear gravitational waves. The second follows the evolution of large scale structures during the later history of the universe and calculates their effect on the 3K background radiation. Their simulations are carried out using modern supercomputers and make heavy use of multidimensional color graphics, including film to elucidate the results. Both projects provide the authors the opportunity to do experiments in cosmology and assess their results against fundamental cosmological observations
Numerical investigation of a Hall thruster plasma
International Nuclear Information System (INIS)
Roy, Subrata; Pandey, B.P.
2002-01-01
The dynamics of the Hall thruster is investigated numerically in the framework of a one-dimensional, multifluid macroscopic description of a partially ionized xenon plasma using finite element formulation. The model includes neutral dynamics, inelastic processes, and plasma-wall interaction. Owing to disparate temporal scales, ions and neutrals have been described by set of time-dependent equations, while electrons are considered in steady state. Based on the experimental observations, a third order polynomial in electron temperature is used to calculate ionization rate. The results show that in the acceleration channel the increase in the ion number density is related to the decrease in the neutral number density. The electron and ion velocity profiles are consistent with the imposed electric field. The electron temperature remains uniform for nearly two-thirds of the channel; then sharply increases to a peak before dropping slightly at the exit. This is consistent with the predicted electron gyration velocity distribution
Numerical studies of impurities in fusion plasmas
International Nuclear Information System (INIS)
Hulse, R.A.
1982-09-01
The coupled partial differential equations used to describe the behavior of impurity ions in magnetically confined controlled fusion plasmas require numerical solution for cases of practical interest. Computer codes developed for impurity modeling at the Princeton Plasma Physics Laboratory are used as examples of the types of codes employed for this purpose. These codes solve for the impurity ionization state densities and associated radiation rates using atomic physics appropriate for these low-density, high-temperature plasmas. The simpler codes solve local equations in zero spatial dimensions while more complex cases require codes which explicitly include transport of the impurity ions simultaneously with the atomic processes of ionization and recombination. Typical applications are discussed and computational results are presented for selected cases of interest
Numerical Prediction of Green Water Incidents
DEFF Research Database (Denmark)
Nielsen, K. B.; Mayer, Stefan
2004-01-01
loads on a moored FPSO exposed to head sea waves. Two cases are investigated: first, green water ona fixed vessel has been analysed, where resulting waterheight on deck, and impact pressure on a deck mounted structure have been computed. These results have been compared to experimental data obtained......Green water loads on moored or sailing ships occur when an incoming wave signigicantly exceeds the freeboard and water runs onto the deck. In this paper, a Navier-Stokes solver with a free surface capturing scheme (i.e. the VOF model; Hirt and Nichols, 1981) is used to numerically model green water...... by Greco (2001) and show very favourable agreement. Second, a full green water incident, including vessel motions has been modelled. In these computations, the vertical motion has been modelled by the use of transfer functions for heave and pitch, but the rotational contribution from the pitch motion has...