Calculation method of Tesla coil
Коломієць, Роман Олександрович
2015-01-01
Tesla coil, despite the simplicity of its design may be called one of the least studied electronic devices. The article is an attempt to bring in various experimental results of general theoretical framework, which is the basis of exact calculation method of Tesla coils. Such calculation should be the starting point to create devices based on it. In order to develop such methods were considered the general principles of designing Tesla coil, reviewed the most famous mathematical models of its...
Methods of core neutronic calculation
International Nuclear Information System (INIS)
Core neutronic calculations lead to the determination of geometry, composition, controls systems and to the core exploitation limits in agreement with the expected performances, with safety rules, technological choices and fuel management methods. Neutronic calculations object are described with physics justifications of hypothesis and approximations. A description and a definition of reactivity and power distribution are also given. A panorama of calculation methods used in the conception of fast breeder and pressure water reactors, are described with numerical aspects and general interest considerations related to the field of these methods and to the industrial options chosen. A complete industrial uses panorama of methods derived from the classical or generalized perturbation theory is followed by the qualification and the definition of the validity field of numerical codes.(A.B.). 88 refs., 6 figs
Friction and wear calculation methods
Kragelsky, I V; Kombalov, V S
1981-01-01
Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a
Calculation Methods for Wallenius’ Noncentral Hypergeometric Distribution
DEFF Research Database (Denmark)
Fog, Agner
2008-01-01
conditional distribution of independent binomial variates given their sum. No reliable calculation method for Wallenius' noncentral hypergeometric distribution has hitherto been described in the literature. Several new methods for calculating probabilities from Wallenius' noncentral hypergeometric...
Methods in nuclear reactors calculations
International Nuclear Information System (INIS)
Studies are made of the neutron transport equation corresponding to the the real and virtual reactors, as well as the starting hypotheses. Methods are developed to solve the transport equation in slab geometry, and Pl; Bl; Ml; Sn and discrete ordinates approximations. (Author)
Pile Load Capacity – Calculation Methods
Directory of Open Access Journals (Sweden)
Wrana Bogumił
2015-12-01
Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.
Assessment of seismic margin calculation methods
Energy Technology Data Exchange (ETDEWEB)
Kennedy, R.P.; Murray, R.C.; Ravindra, M.K.; Reed, J.W.; Stevenson, J.D.
1989-03-01
Seismic margin review of nuclear power plants requires that the High Confidence of Low Probability of Failure (HCLPF) capacity be calculated for certain components. The candidate methods for calculating the HCLPF capacity as recommended by the Expert Panel on Quantification of Seismic Margins are the Conservative Deterministic Failure Margin (CDFM) method and the Fragility Analysis (FA) method. The present study evaluated these two methods using some representative components in order to provide further guidance in conducting seismic margin reviews. It is concluded that either of the two methods could be used for calculating HCLPF capacities. 21 refs., 9 figs., 6 tabs.
Assessment of seismic margin calculation methods
International Nuclear Information System (INIS)
Seismic margin review of nuclear power plants requires that the High Confidence of Low Probability of Failure (HCLPF) capacity be calculated for certain components. The candidate methods for calculating the HCLPF capacity as recommended by the Expert Panel on Quantification of Seismic Margins are the Conservative Deterministic Failure Margin (CDFM) method and the Fragility Analysis (FA) method. The present study evaluated these two methods using some representative components in order to provide further guidance in conducting seismic margin reviews. It is concluded that either of the two methods could be used for calculating HCLPF capacities. 21 refs., 9 figs., 6 tabs
Comparison of methods for calculating water erosion
Svobodová, Pavlína
2011-01-01
Bachelor thesis presents a comparison of methods for calculating water erosion. The aim is to summarize available evidence concerning the problems of water erosion. There are presented some methods how to calculate average annual erosion of soils, and selected models for calculating the erosion immediately. There are also listed possible erosion control measures through which we can at least slow the effects of erosion, rather than stop completely.
A novel algorithmic method for piezoresistance calculation
International Nuclear Information System (INIS)
A novel algorithmic method, based on the different stress distribution on the surface of thin film in an SOI microstructure, is put forward to calculate the value of the silicon piezoresistance on the sensitive film. In the proposed method, we take the Ritz method as an initial theoretical model to calculate the rate of piezoresistance ΔR/R through an integral (the closed area Ω where the surface piezoresistance of the film lies as the integral area and the product of stress σ and piezoresistive coefficient π as the integral object) and compare the theoretical values with the experimental results. Compared with the traditional method, this novel calculation method is more accurate when applied to calculating the value of the silicon piezoresistance on the sensitive film of an SOI pieoresistive pressure sensor. (semiconductor devices)
Methods of bone marrow dose calculation
International Nuclear Information System (INIS)
Several methods of bone marrow dose calculation for photon irradiation were analised. After a critical analysis, the author proposes the adoption, by the Instituto de Radioprotecao e Dosimetria/CNEN, of Rosenstein's method for dose calculations in Radiodiagnostic examinations and Kramer's method in case of occupational irradiation. It was verified by Eckerman and Simpson that for monoenergetic gamma emitters uniformly distributed within the bone mineral of the skeleton the dose in the bone surface can be several times higher than dose in skeleton. In this way, is also proposed the Calculation of tissue-air ratios for bone surfaces in some irradiation geometries and photon energies to be included in the Rosenstein's method for organ dose calculation in Radiodiagnostic examinations. (Author)
Relaxation Method For Calculating Quantum Entanglement
Tucci, R R
2001-01-01
In a previous paper, we showed how entanglement of formation can be defined as a minimum of the quantum conditional mutual information (a.k.a. quantum conditional information transmission). In classical information theory, the Arimoto-Blahut method is one of the preferred methods for calculating extrema of mutual information. We present a new method akin to the Arimoto-Blahut method for calculating entanglement of formation. We also present several examples computed with a computer program called Causa Comun that implements the ideas of this paper.
Reactor perturbation calculations by Monte Carlo methods
International Nuclear Information System (INIS)
Whilst Monte Carlo methods are useful for reactor calculations involving complicated geometry, it is difficult to apply them to the calculation of perturbation worths because of the large amount of computing time needed to obtain good accuracy. Various ways of overcoming these difficulties are investigated in this report, with the problem of estimating absorbing control rod worths particularly in mind. As a basis for discussion a method of carrying out multigroup reactor calculations by Monte Carlo methods is described. Two methods of estimating a perturbation worth directly, without differencing two quantities of like magnitude, are examined closely but are passed over in favour of a third method based on a correlation technique. This correlation method is described, and demonstrated by a limited range of calculations for absorbing control rods in a fast reactor. In these calculations control rod worths of between 1% and 7% in reactivity are estimated to an accuracy better than 10% (3 standard errors) in about one hour's computing time on the English Electric KDF.9 digital computer. (author)
Willow growing - Methods of calculation and profitability
International Nuclear Information System (INIS)
The calculation method presented here makes it possible to conduct profitability comparisons between annual and perennial crops and in addition take the planning situation into account. The method applied is a modified total step calculation. The difference between a traditional total step calculation and the modified version is the way in which payments and disbursements are taken into account over a period of several years. This is achieved by combining the present value method and the annuity method. The choice of interest rate has great bearing on the result in perennial calculations. The various components influencing the interest rate are analysed and factors relating to the establishment of the interest rate in different situations are described. The risk factor can be an important variable component of the interest rate calculation. Risk is also addressed from an approach in accordance with portfolio theory. The application of the methods sheds light on the profitability of Salix cultivation from the viewpoint of business economics, and also how different factors influence the profitability of Salix cultivation. Aspects studied are harvesting intervals, the importance of yield level, the competitiveness of Salix versus grain cultivation, the influence of income taxes on profitability etc. Methods for evaluation of activities concerning cultivation of a perennial crop are described and also involve the application of nitrogen fertilization to Salix cultivation. Studies have been performed using these methods to look into nitrogen fertilizer profitability in Salix cultivation during the first rotation period. Nitrogen fertilizer profitability has been investigated involving both production functions and cost calculations, taking the year fertilization into consideration. 72 refs., 2 figs., 52 tabs
DNBR limit calculation by sampling statistical method
International Nuclear Information System (INIS)
The parametric uncertainties of DNBR and exit quality were calculated using sampling statistical method based on Wilks formula and VIPRE-W code. Then the DNBR design limit and exit quality limit were got by combining with the uncertainties of models and DNB correlation. This method can gain the more DNBR margin than RTDP methodology which is developed by Westinghouse by comparison of these two methods. (authors)
A method for tokamak neutronics calculations
International Nuclear Information System (INIS)
This paper presents a new method for neutron transport calculation in tokamak fusion reactors. The computational procedure is based on the solution of the even-parity transport equation in a toroidal geometry. The angular neutron distribution is treated by even-parity spherical harmonic expansion, while the spatial dependence is approximated by using R-function finite elements that are defined for regions of arbitrary geometric shape. In order to test the method, calculation of a simplified tokamak model is carried out. The results are compared with the results from the literature and for the same order of accuracy a reduction of the number of spatial unknowns is shown. (author)
Multigrid Methods in Electronic Structure Calculations
Briggs, E L; Bernholc, J
1996-01-01
We describe a set of techniques for performing large scale ab initio calculations using multigrid accelerations and a real-space grid as a basis. The multigrid methods provide effective convergence acceleration and preconditioning on all length scales, thereby permitting efficient calculations for ill-conditioned systems with long length scales or high energy cut-offs. We discuss specific implementations of multigrid and real-space algorithms for electronic structure calculations, including an efficient multigrid-accelerated solver for Kohn-Sham equations, compact yet accurate discretization schemes for the Kohn-Sham and Poisson equations, optimized pseudo\\-potentials for real-space calculations, efficacious computation of ionic forces, and a complex-wavefunction implementation for arbitrary sampling of the Brillioun zone. A particular strength of a real-space multigrid approach is its ready adaptability to massively parallel computer architectures, and we present an implementation for the Cray-T3D with essen...
A New Iterative Method to Calculate [pi
Dion, Peter; Ho, Anthony
2012-01-01
For at least 2000 years people have been trying to calculate the value of [pi], the ratio of the circumference to the diameter of a circle. People know that [pi] is an irrational number; its decimal representation goes on forever. Early methods were geometric, involving the use of inscribed and circumscribed polygons of a circle. However, real…
Covariant method for calculating helicity amplitudes
International Nuclear Information System (INIS)
We present an alternative approach for calculating helicity amplitudes for processes involving both massless and massive fermions. With this method one can easily obtain covariant expressions for the helicity amplitudes. The final expressions involve only four-vector products and are independent of the basis for γ matrices or specific form of the spinors. We use the method to obtain the helicity amplitudes for several processes involving top quark production. copyright 1996 The American Physical Society
Hemielectron method generalization for complex compound calculations
International Nuclear Information System (INIS)
A hemielectron method is considered as applied to the systems having one open shell (n electrons on m-fold degenerated level) or several open shells. General expressions for corrections to a total energy of the system and to energies of monoelectron levels, corresponding to an unfilled shell, are obtained. Using the [RuCl6]3- complex as an example, expendiency of the approach application to the calculation of electron structure of coordination compounds is shown
Nodal expansion method for reactor core calculations
International Nuclear Information System (INIS)
To perform realistic space dependent reactor dynamics analyses in large power reactor with all asymmetric material, control and shutdown devices, a full three dimensional calculation model is essential. A code FEMINA (Flux Expansion Method In Nodal Analysis) implementing a higher order nodal scheme employing a nodal flux expansion method in 3D is being developed. In this report the first part of this code viz., the theory of the static version and its validation with well known benchmark problems are described. The code has been found to be quite accurate as well as fast. It is available on DEC 10'', CYBER 170/730 and ND 540 computers. (author)
Acceleration methods and models in Sn calculations
International Nuclear Information System (INIS)
In some neutron transport problems solved by the discrete ordinate method, it is relatively common to observe some particularities as, for example, negative fluxes generation, slow and insecure convergences and solution instabilities. The commonly used models for neutron flux calculation and acceleration methods included in the most used codes were analyzed, in face of their use in problems characterized by a strong upscattering effect. Some special conclusions derived from this analysis are presented as well as a new method to perform the upscattering scaling for solving the before mentioned problems in this kind of cases. This method has been included in the DOT3.5 code (two dimensional discrete ordinates radiation transport code) generating a new version of wider application. (Author)
Methods for calculating radiation attenuation in shields
International Nuclear Information System (INIS)
In recent years the development of high-speed digital computers of large capacity has revolutionized the field of reactor shield design. For compact special-purpose reactor shields, Monte-Carlo codes in two- and three dimensional geometries are now available for the proper treatment of both the neutron and gamma- ray problems. Furthermore, techniques are being developed for the theoretical optimization of minimum-weight shield configurations for this type of reactor system. In the design of land-based power reactors, on the other hand, there is a strong incentive to reduce the capital cost of the plant, and economic considerations are also relevant to reactors designed for merchant ship propulsion. In this context simple methods are needed which are economic in their data input and computing time requirements and which, at the same time, are sufficiently accurate for design work. In general the computing time required for Monte-Carlo calculations in complex geometry is excessive for routine design calculations and the capacity of the present codes is inadequate for the proper treatment of large reactor shield systems in three dimensions. In these circumstances a wide range of simpler techniques are currently being employed for design calculations. The methods of calculation for neutrons in reactor shields fall naturally into four categories: Multigroup diffusion theory; Multigroup diffusion with removal sources; Transport codes; and Monte Carlo methods. In spite of the numerous Monte- Carlo techniques which are available for penetration and back scattering, serious problems are still encountered in practice with the scattering of gamma rays from walls of buildings which contain critical facilities and also concrete-lined discharge shafts containing irradiated fuel elements. The considerable volume of data in the unclassified literature on the solution of problems of this type in civil defence work appears not to have been evaluated for reactor shield design. In
Discontinuous finite element methods for reactor calculations
International Nuclear Information System (INIS)
Variational principles which employ discontinuous shape functions for the angular and/or the spatial component of the neutron flux are established to obtain numerical solutions for neutron diffusion and transport equations. Implementing discontinuous finite element methods reduces the total nodal unknowns and hence the over all computational efforts. This reduction varies from one problem to another. In this paper one group neutron transport problems are solved by varying only the order of spherical harmonic expansion for the angular component of the flux. A comparison of the solutions obtained from the discontinuous approach with either a published solutions or a conventional finite element solutions shows that the method is a very effective tool for reactor calculations
Methods of core neutronic calculation; Methodes de calcul neutronique de coeur
Energy Technology Data Exchange (ETDEWEB)
Bruna, G.B.; Guesdon, B. [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France)
1996-02-01
Core neutronic calculations lead to the determination of geometry, composition, controls systems and to the core exploitation limits in agreement with the expected performances, with safety rules, technological choices and fuel management methods. Neutronic calculations object are described with physics justifications of hypothesis and approximations. A description and a definition of reactivity and power distribution are also given. A panorama of calculation methods used in the conception of fast breeder and pressure water reactors, are described with numerical aspects and general interest considerations related to the field of these methods and to the industrial options chosen. A complete industrial uses panorama of methods derived from the classical or generalized perturbation theory is followed by the qualification and the definition of the validity field of numerical codes.(A.B.). 88 refs., 6 figs.
ANALYTICAL METHODS FOR CALCULATING FAN AERODYNAMICS
Directory of Open Access Journals (Sweden)
Jan Dostal
2015-12-01
Full Text Available This paper presents results obtained between 2010 and 2014 in the field of fan aerodynamics at the Department of Composite Technology at the VZLÚ aerospace research and experimental institute in Prague – Letnany. The need for rapid and accurate methods for the preliminary design of blade machinery led to the creation of a mathematical model based on the basic laws of turbomachine aerodynamics. The mathematical model, the derivation of which is briefly described below, has been encoded in a computer programme, which enables the theoretical characteristics of a fan of the designed geometry to be determined rapidly. The validity of the mathematical model is assessed continuously by measuring model fans in the measuring unit, which was developed and manufactured specifically for this purpose. The paper also presents a comparison between measured characteristics and characteristics determined by the mathematical model as the basis for a discussion on possible causes of measured deviations and calculation deviations.
The matrix method to calculate page rank
Directory of Open Access Journals (Sweden)
H. Barboucha, M. Nasri
2014-06-01
Full Text Available Choosing the right keywords is relatively easy, whereas getting a high PageRank is more complicated. The index Page Rank is what defines the position in the result pages of search engines (for Google of course, but the other engines are now using more or less the same kind of algorithm. It is therefore very important to understand how this type of algorithm functions to hope to appear on the first page of results (the only page read in 95 % of cases or at least be among the first. We propose in this paper to clarify the operation of this algorithm using a matrix method and a JavaScript program enabling to experience this type of analysis. It is of course a simplified version, but it can add value to the website and achieve a high ranking in the search results and reach a larger customer base. The interest is to disclose an algorithm to calculate the relevance of each page. This is in fact a mathematical algorithm based on a web graph. This graph is formed of all the web pages that are modeled by nodes, and hyperlinks that are modeled by arcs.
METHODS OF CALCULATING THE ELECTRONIC AND ATOMIC STRUCTURES OF INTERFACES
Sutton, A
1985-01-01
Methods of calculating the electronic and atomic structures of interfaces are described. An introduction to pseudopotentials and LCAO methods is given. Methods of calculating the electronic structure of an interface with a given atomic structure are considered. The feasibility of total energy calculations, in which the atomic and electronic structures are calculated simultaneously, is discussed.
Overview of multifluid-flow-calculation methods
International Nuclear Information System (INIS)
Two categories of numerical methods which may be useful in multiphase flow research are discussed. The first category includes methods which are specifically intended for accurate computation of discontinuities, such as the method of characteristics, particle-in-cell method, flux-corrected transport, and random choice methods. Methods in this category could be applied to research on rocket exhaust plumes and interior ballistics. The second category includes methods for smooth, subsonic flows, such as fractional step methods, semi-implicit method, and methods which treat convection implicitly. The subsonic flow methods could be of interest for ice flows
Method of integral transforms for calculating few-body reactions
Efros, V. D.; Leidemann, W.; Orlandini, G.
1998-01-01
A non-conventional approach to calculating reactions in quantum mechanics is presented. Reaction observables are obtained with bound state calculation techniques. The accuracy of the method to calculate few-nucleon response functions is discussed.
Method for consequence calculations for severe accidents
International Nuclear Information System (INIS)
This report was commissioned by the Swedish State Power Board. The report contains a calculation of radiation doses in the surroundings caused by a theoretical core meltdown accident at Forsmark reactor No 3. The assumption used for the calculations were a 0.06% release of iodine and cesium corresponding to a 0.1% release through the FILTRA plant at Barsebaeck. The calculations were made by means of the PLUCON4 code. Meteorological data for two years from the Forsmark meteorological tower were analysed to find representative weather situations. As typical weather pasquill D was chosen with wind speed 5 m/s, and as extreme weather, Pasquill F with wind speed 2 m/s. 23 tabs., 36 ills., 21 refs. (author)
A method to calculate Fresnel lenses
International Nuclear Information System (INIS)
In solar engineering, in contrast to image optics, Fresnel lenses are intended for securing the required concentrations of solar radiation and its distribution over a receiver's surface. It is also important to secure a high use coefficient of the concentrated flux. In particular, this defines the features of calculation of Fresnel lenses: it is necessary to take into account inaccuracies in fabrication of Fresnel lenses and solar radiation redistribution by means of selecting the respective parameters of Fresnel lens belts. In the present work, we examine the procedure for the calculating geometrical parameters of Fresnel lenses on a flat base by considering the mentioned requirements. A corresponding software for calculating the geometrical parameters and concentrating characteristics of the Fresnel lenses is developed, and examples of calculation are given. For a constant refractive index of Fresnel lens material, it is shown that the Fresnel lens can secure a concentration of about 1000, but in this case the optical efficiency of the Fresnel lens will not be higher than 70%. The procedure that has been developed may be the basic one for determining the parameters and concentrating characteristics of Fresnel lenses by considering refractive index variance. (author)
Analytic methods for calculating coupling impedances
International Nuclear Information System (INIS)
These lecture notes describe a variety of analytic techniques to calculate the longitudinal and transverse impedances of obstacles in a beam pipe. They also treat the effort to shield these impedances from the beam by appropriate use of thin conducting layers. (orig.)
Computational methods for probability of instability calculations
Wu, Y.-T.; Burnside, O. H.
1990-01-01
This paper summarizes the development of the methods and a computer program to compute the probability of instability of a dynamic system than can be represented by a system of second-order ordinary linear differential equations. Two instability criteria based upon the roots of the characteristics equation or Routh-Hurwitz test functions are investigated. Computational methods based on system reliability analysis methods and importance sampling concepts are proposed to perform efficient probabilistic analysis. Numerical examples are provided to demonstrate the methods.
Method for consequence calculations for severe accidents
International Nuclear Information System (INIS)
This report was commissioned by the Swedish State Power Board. The report contains a calculation of radiation doses in the surroundings caused by a theoretical core meltdown accident at Ringhals reactor No 3/4. The accident sequence chosen for the calcualtions was a release caused by total power failure. The calculations were made by means of the PLUCON4 code. A decontamination factor of 500 is used to account for the scrubber effect. Meteorological data for two years from the Ringhals meteorological tower were analysed to find representative weather situations. As typical weather, Pasquill D, was chosen with a wind speed of 10 m/s, and as extreme weather, Pasquill E, with a wind speed of 2 m/s. 19 refs. (author)
COSTS CALCULATION OF TARGET COSTING METHOD
UNGUREANU Sebastian
2014-01-01
Cost information system plays an important role in every organization in the decision making process. An important task of management is ensuring control of the operations, processes, sectors, and not ultimately on costs. Although in achieving the objectives of an organization compete more control systems (production control, quality control, etc.), the cost information system is important because monitors results of the other. Detailed analysis of costs, production cost calculation, quantifi...
Methods for calculating anisotropic transfer cross sections
International Nuclear Information System (INIS)
The Legendre moments of the group transfer cross section, which are widely used in the numerical solution of the transport calculation can be efficiently and accurately constructed from low-order (K = 1--2) successive partial range moments. This is convenient for the generation of group constants. In addition, a technique to obtain group-angle correlation transfer cross section without Legendre expansion is presented. (author)
Monte Carlo method application to shielding calculations
International Nuclear Information System (INIS)
CANDU spent fuel discharged from the reactor core contains Pu, so it must be stressed in two directions: tracing for the fuel reactivity in order to prevent critical mass formation and personnel protection during the spent fuel manipulation. The basic tasks accomplished by the shielding calculations in a nuclear safety analysis consist in dose rates calculations in order to prevent any risks both for personnel protection and impact on the environment during the spent fuel manipulation, transport and storage. To perform photon dose rates calculations the Monte Carlo MORSE-SGC code incorporated in SAS4 sequence from SCALE system was used. The paper objective was to obtain the photon dose rates to the spent fuel transport cask wall, both in radial and axial directions. As source of radiation one spent CANDU fuel bundle was used. All the geometrical and material data related to the transport cask were considered according to the shipping cask type B model, whose prototype has been realized and tested in the Institute for Nuclear Research Pitesti. (authors)
Calculation of radon concentration in water by toluene extraction method
Energy Technology Data Exchange (ETDEWEB)
Saito, Masaaki [Tokyo Metropolitan Isotope Research Center (Japan)
1997-02-01
Noguchi method and Horiuchi method have been used as the calculation method of radon concentration in water. Both methods have two problems in the original, that is, the concentration calculated is changed by the extraction temperature depend on the incorrect solubility data and the concentration calculated are smaller than the correct values, because the radon calculation equation does not true to the gas-liquid equilibrium theory. However, the two problems are solved by improving the radon equation. I presented the Noguchi-Saito equation and the constant B of Horiuchi-Saito equation. The calculating results by the improved method showed about 10% of error. (S.Y.)
A review of calculation methods for fast and intermediate reactors
International Nuclear Information System (INIS)
This paper discusses the development of methods for calculating intermediate and fast reactors. It deals with various approaches to the problems of physical calculation. The calculation of resonance effects is discussed. Consideration is given to multi-group systems of fundamental and conjugate equations, various applications of perturbation theory to the problems of physical reactor calculation, and numerical methods of solving fundamental and conjugate reactor equations, which approximate the method of spherical harmonics. The paper describes an application of the response method to the solution of critical-mass problems, and methods of calculating reactors with hydrogeneous moderators. The fundamental features of an effective one-group reactor model are described. (author)
COSTS CALCULATION OF TARGET COSTING METHOD
Directory of Open Access Journals (Sweden)
Sebastian UNGUREANU
2014-06-01
Full Text Available Cost information system plays an important role in every organization in the decision making process. An important task of management is ensuring control of the operations, processes, sectors, and not ultimately on costs. Although in achieving the objectives of an organization compete more control systems (production control, quality control, etc., the cost information system is important because monitors results of the other. Detailed analysis of costs, production cost calculation, quantification of losses, estimate the work efficiency provides a solid basis for financial control. Knowledge of the costs is a decisive factor in taking decisions and planning future activities. Managers are concerned about the costs that will appear in the future, their level underpinning the supply and production decisions as well as price policy. An important factor is the efficiency of cost information system in such a way that the information provided by it may be useful for decisions and planning of the work.
Investigation of Calculation Techniques of Finite Difference Method
Directory of Open Access Journals (Sweden)
Audrius Krukonis
2011-03-01
Full Text Available Finite difference method used for microstrip transmission line analysis is considered in this article. Paper mainly deals with iterative and bound matrix calculation techniques of finite difference method. Mathematical model for microstrip transmission line electrical potential calculations using both techniques is described. Results of characteristic impedance calculation using iterative and bound matrix techniques are presented and analyzed.Article in Lithuanian
Approximate methods in gamma-ray skyshine calculations
International Nuclear Information System (INIS)
An approximate computational method for gamma-ray skyshine calculations is described. The method is suitable for a source collimated uniformly about the vertical and accounts for uniform overhead concrete shielding above the source. Results of calculations are compared to measurements as well as results of other calculations
Transportation channels calculation method in MATLAB
International Nuclear Information System (INIS)
Output devices and charged particles transport channels are necessary components of any modern particle accelerator. They differ both in sizes and in terms of focusing elements depending on particle accelerator type and its destination. A package of transport line designing codes for magnet optical channels in MATLAB environment is presented in this report. Charged particles dynamics in a focusing channel can be studied easily by means of the matrix technique. MATLAB usage is convenient because its information objects are matrixes. MATLAB allows the use the modular principle to build the software package. Program blocks are small in size and easy to use. They can be executed separately or commonly. A set of codes has a user-friendly interface. Transport channel construction consists of focusing lenses (doublets and triplets). The main of the magneto-optical channel parameters are total length and lens position and parameters of the output beam in the phase space (channel acceptance, beam emittance - beam transverse dimensions, particles divergence and image stigmaticity). Choice of the channel operation parameters is based on the conditions for satisfying mutually competing demands. And therefore the channel parameters calculation is carried out by using the search engine optimization techniques.
Calculation methods for neutron radiography spatial resolution
International Nuclear Information System (INIS)
Spatial resolution is an important parameter for neutron radiography facility. In this paper, different methods to define the spatial resolution,such as point spread function (PSF), line spread function (LSF), edge spread function (ESF) and modulation transfer function (MTF), are analyzed and compared. MTF turns out to be the best, as it is derived from the linear system theory in a given frequency domain, and gives the maximum amount of useful information on system signal modulation. (authors)
Progress and prospects of calculation methods for radiation shielding
International Nuclear Information System (INIS)
Progress in calculation methods for radiation shielding are reviewed based on the activities of research committees related to radiation shielding fields established in the Atomic Energy Society of Japan. A technological roadmap for the field of radiation shielding; progress and prospects for specific shielding calculation methods such as the Monte Carlo, discrete ordinate Sn transport, and simplified methods; and shielding experiments used to validate calculation methods are presented in this paper. (author)
Nodal methods in numerical reactor calculations
International Nuclear Information System (INIS)
The present work describes the antecedents, developments and applications started in 1972 with Prof. Hennart who was invited to be part of the staff of the Nuclear Engineering Department at the School of Physics and Mathematics of the National Polytechnic Institute. Since that time and up to 1981, several master theses based on classical finite element methods were developed with applications in point kinetics and in the steady state as well as the time dependent multigroup diffusion equations. After this period the emphasis moved to nodal finite elements in 1, 2 and 3D cartesian geometries. All the thesis were devoted to the numerical solution of the neutron multigroup diffusion and transport equations, few of them including the time dependence, most of them related with steady state diffusion equations. The main contributions were as follows: high order nodal schemes for the primal and mixed forms of the diffusion equations, block-centered finite-differences methods, post-processing, composite nodal finite elements for hexagons, and weakly and strongly discontinuous schemes for the transport equation. Some of these are now being used by several researchers involved in nuclear fuel management. (Author)
Sectoring method for cosmic radiation shielding calculation for LEO satellite
International Nuclear Information System (INIS)
One of an approximate calculation model (sectoring method) is developed for a cosmic radiation shielding in satellite. Shielding calculation is performed for KITSAT-1 at the assumed SAA (South Atlatic Anomaly) location with AP-8 model radiation spectrum. When sectoring method is applied, calculation error is expected compared with 3-D detailed geometry calculation because of straight knock-on assumption neglecting the deflection of incident proton. However, sectoring method shows good agreements with 3-dimensional detailed Monte Carlo calculation in two TID detector locations
Quantum Monte Carlo diagonalization method as a variational calculation
Energy Technology Data Exchange (ETDEWEB)
Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio
1997-05-01
A stochastic method for performing large-scale shell model calculations is presented, which utilizes the auxiliary field Monte Carlo technique and diagonalization method. This method overcomes the limitation of the conventional shell model diagonalization and can extremely widen the feasibility of shell model calculations with realistic interactions for spectroscopic study of nuclear structure. (author)
The TAB method for numerical calculation of spray droplet breakup
Orourke, P. J.; Amsden, A. A.
A short history is given of the major milestones in the development of the stochastic particle method for calculating liquid fuel sprays. The most recent advance has been the discovery of the importance of drop breakup in engine sprays. A new method, called TAB, for calculating drop breakup is presented. Some theoretical properties of the method are derived; its numerical implementation in the computer program KIVA is described; and comparisons are presented between TAB-method calculations and experiments and calculations using another breakup model.
Comments on Simplified Calculation Method for Fire Exposed Concrete Columns
DEFF Research Database (Denmark)
Hertz, Kristian Dahl
1998-01-01
The author has developed new simplified calculation methods for fire exposed columns. Methods, which are found In ENV 1992-1-2 chapter 4.3 and in proposal for Danish code of Practise DS411 chapter 9. In the present supporting document the methods are derived and 50 eccentrically loaded fire exposed...... columns are calculated and compared to results of full-scale tests. Furthermore 500 columns are calculated in order to present each test result related to a variation of the calculation in time of fire resistance....
A Damping Characteristics Calculation Method of Metal Dry Friction Isolators
Institute of Scientific and Technical Information of China (English)
JIANG Hong-yuan; HAO De-gang; XIA Yu-hong; ULANOV A M; PONOMAREV Yu K
2008-01-01
The dry friction ring-type vibration isolator is considered as an isotropic continuous medium. A method of dry friction hysteresis loop calculation is proposed based on friction force analysis of contact beam. The friction force is modeled as an equivalent distributed moment to use the finite element method (FEM) to calculate the dry friction vibration isolator hysteresis loop, so the damping characteristics can be obtained. A comparison of the hysteresis loop calculation results and the experimental results shows the average relative error is 2.7%, it proves the calculation method is feasible.
Some methods for calculation of perturbations in nuclear reactors
Energy Technology Data Exchange (ETDEWEB)
Abramov, B. D., E-mail: abramov@ippe.ru [Leypunsky Institute of Physics and Power Engineering (Russian Federation)
2015-12-15
Some methods for calculation of local perturbations of neutron fields and reactivity effects accompanying them are considered. Existence, uniqueness, properties and methods for finding solutions to the considered problems are discussed.
Evolution of calculation methods taking into account severe accidents
International Nuclear Information System (INIS)
During the first decade of PWRs operation in France the calculation methods used for design and operation have improved very much. This paper gives a general analysis of the calculation methods evolution in parallel with the evolution of safety approach concerning PWRs. Then a comprehensive presentation of principal calculation tools is presented as applied during the past decade. An effort is done to predict the improvements in near future
A New Method for Calculating the Thermoelectric Efficiency
Institute of Scientific and Technical Information of China (English)
吴一东; 王志敏; 何元金
2004-01-01
We present an approximate method for calculating the thermoelectric effciency. The method has a high precision and is applicable to almost all of the thermoelectric devices. The expression for the thermoelectric efficiency we obtained does not involve the position variable, so the calculations are simplified greatly.
Calculation of transonic flows using an extended integral equation method
Nixon, D.
1976-01-01
An extended integral equation method for transonic flows is developed. In the extended integral equation method velocities in the flow field are calculated in addition to values on the aerofoil surface, in contrast with the less accurate 'standard' integral equation method in which only surface velocities are calculated. The results obtained for aerofoils in subcritical flow and in supercritical flow when shock waves are present compare satisfactorily with the results of recent finite difference methods.
Iterative acceleration methods for Monte Carlo and deterministic criticality calculations
International Nuclear Information System (INIS)
If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors
Iterative acceleration methods for Monte Carlo and deterministic criticality calculations
Energy Technology Data Exchange (ETDEWEB)
Urbatsch, T.J.
1995-11-01
If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.
Approximate design calculation methods for radiation streaming in shield irregularities
International Nuclear Information System (INIS)
Investigation and assessment are made for approximate design calculation methods of radiation streaming in shield irregularities. Investigation is made for (1) source, (2) definition of streaming radiation components, (3) calculation methods of streaming radiation, (4) streaming formulas for each irregularity, (5) difficulties in application of streaming formulas, etc. Furthermore, investigation is made for simple calculation codes and albedo data. As a result, it is clarified that streaming calculation formulas are not enough to cover various irregularities and their accuracy or application limit is not sufficiently clear. Accurate treatment is not made in the formulas with respect to the radiation behavior for slant incidence, bend part, offset etc., that results in too much safety factors in the design calculation and distrust of the streaming calculation. To overcome the state and improve the accuracy of the design calculation for shield irregularities, it is emphasized to assess existing formulas and develop better formulas based on systematic experimental studies. (author)
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The improved form of calculation formula for the activities of the components in binary liquids and solid alloys has been derived based on the free volume theory considering excess entropy and Miedema's model for calculating the formation heat of binary alloys. A calculation method of excess thermodynamic functions for binary alloys, the formulas of integral molar excess properties and partial molar excess properties for solid ordered or disordered binary alloys have been developed. The calculated results are in good agreement with the experimental values.
A finite element method for SSI time history calculation
International Nuclear Information System (INIS)
The method which is proposed is based on a finite element modelization for the soil and the structure and a time history calculation. It has been developed for plane and axisymmetric geometries. The principle of this method is presented, then applications are given, first to a linear calculation for which results will be compared to those obtained by standard methods. Then results for a non linear behavior are described
Ore reserve calculation methods used by Eldorado Nuclear Limited
International Nuclear Information System (INIS)
Uranium-bearing pitchblende deposits of the Beaverlodge area in northern Saskatchewan are highly complex. The ideas and concepts of ore reserve calculation methods employed by Eldorado Nuclear Limited in assessing and planning the mining of these deposits are described. A manual block-system of ore reserve calculation was used before the adoption of the current computerized system. Four classifications are used for ore reserves calculated by the system, which provides two main program jobs for calculating ore reserves and several additional ones that involve calculations and graphical presentation of ore reserve information for use in mine planning. A comparison of production statistics and ore reserve calculations illustrates the accuracy of the method. (author)
Comparison of calculational methods for EBT reactor nucleonics
International Nuclear Information System (INIS)
Nucleonic calculations for a preliminary conceptual design of the first wall/blanket/shield/coil assembly for an EBT reactor are described. Two-dimensional Monte Carlo, and one- and two-dimensional discrete-ordinates calculations are compared. Good agreement for the calculated values of tritium breeding and nuclear heating is seen. We find that the three methods are all useful and complementary as a design of this type evolves
New method for calculation of integral characteristics of thermal plumes
DEFF Research Database (Denmark)
Zukowska, Daria; Popiolek, Zbigniew; Melikov, Arsen Krikor
2008-01-01
A method for calculation of integral characteristics of thermal plumes is proposed. The method allows for determination of the integral parameters of plumes based on speed measurements performed with omnidirectional low velocity thermoanemometers. The method includes a procedure for calculation of...... of a sitting occupant. The improvement in calculation of the characteristics of the thermal plume achieved with the developed method, in comparison with methods used and reported in the literature, is demonstrated....... the directional velocity (upward component of the mean velocity). The method is applied for determination of the characteristics of an asymmetric thermal plume generated by a sitting person. The method was validated in full-scale experiments in a climatic chamber with a thermal manikin as a simulator...
Elongation method for electronic structure calculations of random DNA sequences.
Orimoto, Yuuichi; Liu, Kai; Aoki, Yuriko
2015-10-30
We applied ab initio order-N elongation (ELG) method to calculate electronic structures of various deoxyribonucleic acid (DNA) models. We aim to test potential application of the method for building a database of DNA electronic structures. The ELG method mimics polymerization reactions on a computer and meets the requirements for linear scaling computational efficiency and high accuracy, even for huge systems. As a benchmark test, we applied the method for calculations of various types of random sequenced A- and B-type DNA models with and without counterions. In each case, the ELG method maintained high accuracy with small errors in energy on the order of 10(-8) hartree/atom compared with conventional calculations. We demonstrate that the ELG method can provide valuable information such as stabilization energies and local densities of states for each DNA sequence. In addition, we discuss the "restarting" feature of the ELG method for constructing a database that exhaustively covers DNA species. PMID:26337429
Fluid-structure interaction calculations using a linear perturbation method
International Nuclear Information System (INIS)
Aim of the work is to present and validate FSI (Fluid-Structure Interaction) calculations by using a linear perturbation method and commercial Computational Fluid Dynamics (CFD) and structural analysis codes. Star-CD is used for CFD calculations and ABAQUS for structural analysis. The external MpCCI code is used for coupling the CFD and structural analysis codes
Protein-protein binding affinities calculated using the LIE method
Andberg, Tor Arne Heim
2011-01-01
Absolute binding free energies for the third domain of the turkey ovomucoid inhibitor in complex with Streptomyces griseus proteinase B and porcine pancreatic elastase has been calculated using the linear interaction energy method.
A new method to calculate hole subbands of semiconductors hetrostructures
International Nuclear Information System (INIS)
A new method, ordinary boundary method (OBM), is suggested to calculate the hole subbands and wavefunctions of semiconductor hetrostructures. Based on it, a transfer matrix is established. By means of it not only the hole subbands and wavefunctions of hetrostructures can be calculated rigorously and quickly but also the asymptotic transfer method can be generalized to calculate the hole subbands of complex systems in which the valence bandedges are oblique lines or curves. As examples we calculated the hole subbands of GaAs/AlxGa1-xAs quantum well and GaAs/AlxGa1-xAs superlattice in terms of both OBM and transfer matrix method. (author). 7 refs, 4 figs
A valid method of calculating virtual scene depth
Institute of Scientific and Technical Information of China (English)
QUAN Hong-yan; ZHANG Tian-wen; LIN Xiang-hong
2005-01-01
A valid method of virtual scene depth calculating is put forward. In this method cameras rotate in three different viewpoints in the plane and we calculate the depth of panorama using three stitching cylinder panoramas. In the investigation, the column of panorama is regarded as a slot image. Using the conic intersected by the epipolar plane and the cylinder, we can obtain the perpendicularity disparity. In order to obtain dense correspondence fast and accurately, a new method of obtaining horizontal disparity using depth continuity is also put forward. It converts the problem of panorama dense correspondence to the problem of searching points in the conic. The occlusion problem is dealt with using three cylinders in the depth calculation. It is verified that this method is convenient, useful and efficient in calculating the depth of a virtual scene.
Comparison study on cell calculation method of fast reactor
International Nuclear Information System (INIS)
Effective cross sections obtained by cell calculations are used in core calculations in current deterministic methods. Therefore, it is important to calculate the effective cross sections accurately and several methods have been proposed. In this study, some of the methods are compared to each other using a continuous energy Monte Carlo method as a reference. The result shows that the table look-up method used in Japan Nuclear Cycle Development Institute (JNC) sometimes has a difference over 10% in effective microscopic cross sections and be inferior to the sub-group method. The problem was overcome by introducing a new nuclear constant system developed in JNC, in which the ultra free energy group library is used. The system can also deal with resonance interaction effects between nuclides which are not able to be considered by other methods. In addition, a new method was proposed to calculate effective cross section accurately for power reactor fuel subassembly where the new nuclear constant system cannot be applied. This method uses the sub-group method and the ultra fine energy group collision probability method. The microscopic effective cross sections obtained by this method agree with the reference values within 5% difference. (author)
Seismic response based on transient calculations. Spectral and stochastic methods
International Nuclear Information System (INIS)
Further to the recent development in the ASTER code of functionalities enabling random dynamic responses to be calculated, notably a stochastic type seismic analysis, we propose a combination of three calculation methods to estimate a probabilistic seismic response on an N4 reactor building stick-model. Transient calculations involves time-and cost-consuming repetition. The conventional oscillator response spectrum calculation yields only the maximum response expectation. On the other hand, the stochastic approach in this context gives the response corresponding to selected probabilities. (authors). 12 figs., 3 tabs., 4 refs
Methods for tornado frequency calculation of nuclear power plant
International Nuclear Information System (INIS)
In order to take probabilistic safety assessment of nuclear power plant tornado attack event, a method to calculate tornado frequency of nuclear power plant is introduced based on HAD 101/10 and NUREG/CR-4839 references. This method can consider history tornado frequency of the plant area, construction dimension, intensity various along with tornado path and area distribution and so on and calculate the frequency of different scale tornado. (authors)
Calculating expected deaths: a comparison of two methods.
Chovil, A C
1987-01-01
A comparison is presented between the traditional "person-years" and more recently described "prospective model" methods for calculating mortality expectations. Problems arising from the fact that expectations under the person-years method are calculated on the basis that a null hypothesis is true, which results in artificial figures that, at least theoretically, are meaningless if the hypothesis is rejected, are discussed. Data are presented from two studies in which expectations have been c...
CALCULATION OF COMPANY COSTS THROUGH THE DIRECT-COSTING CALCULATION METHOD
Directory of Open Access Journals (Sweden)
Florin-Constantin DIMA
2013-06-01
Full Text Available The cost of production has as its starting point the purchase cost of raw materials and consumables, as well as their processing cost and the calculation of the production cost involves complex aspects. This article is based on the two major concepts of costs calculation, namely the concept of full costs and the concept of partial costs, and it analyses the direct-costing calculation method. Necessity of the Development of calculation methods to ensure rapid determination of the cost of production, and the establishment of indicators broad spectrum of information necessary for making decisions to streamline a business activity conducted by direct-costing method. Direct-costing method appeared in the U.S. for the first time in 1934 (applied by Jonathan Harris and G. Charter Harrison. Subsequently, this method was applied to European countries (England, France, Germany etc.. We stopped on this method because it is considered a modern method of costing. Therefore, we analyzed both advantages and limitations of the method in question
Simplified hourly method to calculate summer temperatures in dwellings
DEFF Research Database (Denmark)
Mortensen, Lone Hedegaard; Aggerholm, Søren
2012-01-01
with further simplifications. The method is used for calculating room temperatures for all hours of a reference year. It is essential that the simplified method is able to predict the temperature in the room with the highest heat load. The heat load is influenced by the solar load, internal load...... and solar load. The developed method can calculate the number of hours above a given temperature limit. The limits are a prerequisite for the development of the simplified method, and a supplementary maximum temperature limit is suggested to ensure robustness. The setting of the ventilation rate is...
Development of 3-D detailed FBR core calculation method based on method of characteristics
International Nuclear Information System (INIS)
A new detailed 3-D transport calculation method taking into account the heterogeneity of fuel assemblies has been developed in hexagonal-z geometry by combining the method of characteristics (MOC) and the nodal transport method. From the nodal transport calculation which uses assembly homogenized cross sections, the axial leakage is calculated, and it is used for the MOC calculation which treats the heterogeneity of fuel assemblies. Series of homogeneous MOC calculations which use assembly homogeneous cross sections are carried out to obtain effective cross sections, which preserve assembly reaction rates. This effective cross sections are again used in the 3-dimensional nodal transport calculation. The numerical calculations have been performed to verify 3-dimensional radial calculations of FBR (fast breeder reactor) assemblies and partial core calculations. Results are compared with the reference Monte-Carlo calculations. A good agreement has been achieved. It is shown that the present method has an advantage in calculating reaction rates in a small region. (authors)
Comparison of MCNPX and Albedo method in criticality calculation
International Nuclear Information System (INIS)
This study aims to conduct a computer simulation that will calculate the reactivity of a homogeneous reactor and compare the results with the calculations made by the albedo method. The simulation will be developed using the MCNPX. The study compared the results calculated for a hypothetical reactor by the albedo method for four groups of energy with those obtained by the MCNPX simulation. The design of the reactor is spherical and homogeneous with a reflector of finite thickness. The value obtained for the neutron effective multiplication factor - keff will be compared. Different situations were simulated in order to obtain results closer to the compared method and reality. The was Good consistency could be noticed between the calculated results. (author)
Calculation method for gamma dose rates from Gaussian puffs
International Nuclear Information System (INIS)
The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of Eγ, σy, the asymmetry factor - σy/σz, the height of puff center - H and the distance from puff center Rxy. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs
Calculation method for gamma-dose rates from spherical puffs
International Nuclear Information System (INIS)
The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δp) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)
International Nuclear Information System (INIS)
According to the acceptance of ICRP Publication 60 (1990), the dose equivalent limit for the boarder of controlled area will be defined as 1.3 mSv/3 months in the Regulation for the Enforcement of the Medical Service Law which is scheduled to be revised. The calculating methods of radiation shielding to be considered are as follows: The first method is calculating the dose equivalent for each nuclide using 3-month maximum estimated use dose. The second method is calculating the dose equivalent using 3-month maximum estimated use dose after the conversion of all nuclide dose into that of 131I. The third method is calculating the dose equivalent using 1 day maximum estimated use dose after the conversion of all nuclide dose into that of 131I. We've investigated which of methods can meet the new regulation value (1.3 mSv/3 months). In modeled facility, we've tried to calculate the dose by the first method to confirm if we can perform the reasonable control in safe. Total dose equivalent for the boarder of controlled area (B) was 883 μSv/3 months by the first method, and its value turned out to be about 1/4 of that of the third method. Only the result by the first method was found to be within the confines of new dose equivalent limit of 1.3 mSv/3 months. The results of both method the second and the third were found to be within the confines of existing dose equivalent limit. The method as to calculate the shielding for each nuclide by using 3-month maximum estimated use dose has been accepted in the Law Concerning Prevention from Radiation Hazards due to Radioisotopes, etc. As the method is practically in accordance with the current use of radioisotope in nuclear medicine facility, the possibility of it coping with the new dose equivalent limit was indicated. (author)
Application of nonparametric statistic method for DNBR limit calculation
International Nuclear Information System (INIS)
Background: Nonparametric statistical method is a kind of statistical inference method not depending on a certain distribution; it calculates the tolerance limits under certain probability level and confidence through sampling methods. The DNBR margin is one important parameter of NPP design, which presents the safety level of NPP. Purpose and Methods: This paper uses nonparametric statistical method basing on Wilks formula and VIPER-01 subchannel analysis code to calculate the DNBR design limits (DL) of 300 MW NPP (Nuclear Power Plant) during the complete loss of flow accident, simultaneously compared with the DL of DNBR through means of ITDP to get certain DNBR margin. Results: The results indicate that this method can gain 2.96% DNBR margin more than that obtained by ITDP methodology. Conclusions: Because of the reduction of the conservation during analysis process, the nonparametric statistical method can provide greater DNBR margin and the increase of DNBR margin is benefited for the upgrading of core refuel scheme. (authors)
A simple method for calculating Clebsch-Gordan coefficients
Energy Technology Data Exchange (ETDEWEB)
Klink, W H; Wickramasekara, S, E-mail: william-klink@uiowa.ed, E-mail: wickrama@grinnell.ed, E-mail: s-wickram@uiowa.ed [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)
2010-09-15
This paper presents a simple method for calculating Clebsch-Gordan coefficients for the tensor product of two unitary irreducible representations (UIRs) of the rotation group. The method also works for multiplicity-free irreducible representations appearing in the tensor product of any number of UIRs of the rotation group. The generalization to representations with multiplicity is straightforward and briefly discussed.
Efficient Calculation of Near Fields in the FDTD Method
DEFF Research Database (Denmark)
Franek, Ondrej
2011-01-01
When calculating frequency-domain near fields by the FDTD method, almost 50 % reduction in memory and CPU operations can be achieved if only E-fields are stored during the main time-stepping loop and H-fields computed later. An improved method of obtaining the H-fields from Faraday's Law is...
New methods for neutron response calculations with MCNP
International Nuclear Information System (INIS)
MCNP4B was released for international distribution in February, 1997. The author summarized the new MCNP4B features since the release of MCNP4A over three years earlier and compare some results. Then he describes new methods being developed for future code releases. The focus is methods and applications of ex-core neutron response calculations
Experimental verification of a recursive method to calculate evapotranspiration
Recently, a recursive combination method (RCM) to calculate potential and crop evapotranspiration (ET) was given by Lascano and Van Bavel (Agron. J. 2007, 99:585–590). The RCM differs from the Penman-Monteith (PM) method, the main difference being that the assumptions made regarding the temperature ...
Calculation of Solar Radiation by Using Regression Methods
Kızıltan, Ö.; Şahin, M.
2016-04-01
In this study, solar radiation was estimated at 53 location over Turkey with varying climatic conditions using the Linear, Ridge, Lasso, Smoother, Partial least, KNN and Gaussian process regression methods. The data of 2002 and 2003 years were used to obtain regression coefficients of relevant methods. The coefficients were obtained based on the input parameters. Input parameters were month, altitude, latitude, longitude and landsurface temperature (LST).The values for LST were obtained from the data of the National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer (NOAA-AVHRR) satellite. Solar radiation was calculated using obtained coefficients in regression methods for 2004 year. The results were compared statistically. The most successful method was Gaussian process regression method. The most unsuccessful method was lasso regression method. While means bias error (MBE) value of Gaussian process regression method was 0,274 MJ/m2, root mean square error (RMSE) value of method was calculated as 2,260 MJ/m2. The correlation coefficient of related method was calculated as 0,941. Statistical results are consistent with the literature. Used the Gaussian process regression method is recommended for other studies.
On-line reactivity calculation using Lagrange method
International Nuclear Information System (INIS)
Highlights: • Lagrange method is proposed for on-line reactivity calculation in nuclear reactors. • The need for nuclear power history or the Laplace transform is vanished. • The three- and five-point formulas are presented and examined in different benchmark cases. • Computational time-steps of up to 1 s lead to highly reliable reactivity calculations. • The main advantage of the proposed approach is its stability and convergence in large time-step calculations. - Abstract: In this paper, a novel multi-step method is proposed for solving the inverse point kinetics problem using Lagrange polynomial method. By use of this approach, the need for nuclear power history or the Laplace transform is vanished. Furthermore, the accuracy of the method is of order hn for the (n + 1)-point formula, where h is the computational time-step. The three- and five-point formulas of the Lagrange method are used for on-line reactivity calculations and results are benchmarked against reference solutions for different nuclear power forms. Moreover, results for different computational time-steps are compared in each case. The results show the accuracy of the proposed method in all benchmarking cases. For slow transients (large reactor periods), it is shown that time-steps of up to 1 s lead to highly reliable reactivity calculations. However, the optimal time-step in almost all cases is shown to be 0.1 s. The main advantage of the proposed approach, in contrast with previous numerical methods, is its stability and convergence in large time-step calculations. The proposed method can be used as real time reactivity meter in all nuclear reactors without limitation of nuclear power form
Calculating atomic and molecular properties using variational Monte Carlo methods
International Nuclear Information System (INIS)
The authors compute a number of properties for the 1 1S, 21S, and 23S states of helium as well as the ground states of H2 and H/+3 using Variational Monte Carlo. These are in good agreement with previous calculations (where available). Electric-response constants for the ground states of helium, H2 and H+3 are computed as derivatives of the total energy. The method used to calculate these quantities is discussed in detail
Refinement of thermal imager minimum resolvable temperature difference calculating method
Kolobrodov, V. G.; Mykytenko, V. I.
2015-11-01
Calculating methods, which accurately predict minimum resolvable temperature difference (MRTD), are of significant interest for many years. The article deals with improvement the accuracy of determining the thermal imaging system MRTD by elaboration the visual perception model. We suggest MRTD calculating algorithm, which is based on a reliable approximation of the human visual system modulation transfer function (MTF) proposed by N. Nill. There was obtained a new expression for the bandwidth evaluation, which is independent of angular size of the Foucault bar target.
The analytic method for calculating the control rod worth
International Nuclear Information System (INIS)
We calculated the control rod worth in this paper. To avoid complexity, we did not consider burnable poisons and soluble boron. The system was localized within one assembly. The control rod was treated as not an absorber but an another boundary. Thus all of the group constants were unchanged before and after control rod insertion. And we discussed the method for calculation of the reactivity of the whole core
Neutron transport calculations using Quasi-Monte Carlo methods
Energy Technology Data Exchange (ETDEWEB)
Moskowitz, B.S.
1997-07-01
This paper examines the use of quasirandom sequences of points in place of pseudorandom points in Monte Carlo neutron transport calculations. For two simple demonstration problems, the root mean square error, computed over a set of repeated runs, is found to be significantly less when quasirandom sequences are used ({open_quotes}Quasi-Monte Carlo Method{close_quotes}) than when a standard Monte Carlo calculation is performed using only pseudorandom points.
Nuclear data and multigroup methods in fast reactor calculations
International Nuclear Information System (INIS)
The work deals with fast reactor multigroup calculations, and the efficient treatment of basic nuclear data, which serves as raw material for the calculations. Its purpose is twofold: to build a computer code system that handles a large, detailed library of basic neutron cross section data, (such as ENDF/B-III) and yields a compact set of multigroup cross sections for reactor calculations; to use the code system for comparative analysis of different libraries, in order to discover basic uncertainties that still exist in the measurement of neutron cross sections, and to determine their influence upon uncertainties in nuclear calculations. A program named NANICK which was written in two versions is presented. The first handles the American basic data library, ENDF/B-III, while the second handles the German basic data library, KEDAK. The mathematical algorithm is identical in both versions, and only the file management is different. This program calculates infinitely diluted multigroup cross sections and scattering matrices. It is complemented by the program NASIF that calculates shielding factors from resonance parameters. Different versions of NASIF were written to handle ENDF/B-III or KEDAK. New methods for evaluating in reactor calculations the long term behavior of the neutron flux as well as its fine structure are described and an efficient calculation of the shielding factors from resonance parameters is offered. (B.G.)
Shape integral method for magnetospheric shapes. [boundary layer calculations
Michel, F. C.
1979-01-01
A method is developed for calculating the shape of any magnetopause to arbitrarily high precision. The method uses an integral equation which is evaluated for a trial shape. The resulting values of the integral equation as a function of auxiliary variables indicate how close one is to the desired solution. A variational method can then be used to improve the trial shape. Some potential applications are briefly mentioned.
Improvement of fitting method of multiband parameters for cell calculations
International Nuclear Information System (INIS)
To accurately perform cell calculations of nuclear reactors, a new fitting procedure has been developed for calculating multiband parameters, which are necessary for effective cross section calculations. By using the new fitting procedure, the error of multiband parameters becomes always zero. Reactor cell calculations have been performed to compare the effective cross sections and the infinite multiplication factors etc. calculated using the multiband parameters obtained by the new and the conventional fitting procedures by using the cross section set based on the JENDL-3.1 library with 107 energy groups. It is found that there is a small difference of the calculational results between the two fitting procedures and it is found from burnup calculations that the difference of the infinite multiplication factors is not dependent on the burnup period up to about 30 GWd/t. The onion skin effect can be exactly treated by dividing a fuel pellet to multiple regions and by using the multiband method. Thus the difference of burnup properties between two fitting procedures are investigated for the divided and the undivided fueled cells. The total inventory of Pu, Am etc. at the divided case is almost the same to the undivided case at the end of the burnup period. However it is found that the radial distribution of atomic density is slightly different between the two fitting procedures. (author)
Composite electron propagator methods for calculating ionization energies
Díaz-Tinoco, Manuel; Dolgounitcheva, O.; Zakrzewski, V. G.; Ortiz, J. V.
2016-06-01
Accurate ionization energies of molecules may be determined efficiently with composite electron-propagator (CEP) techniques. These methods estimate the results of a calculation with an advanced correlation method and a large basis set by performing a series of more tractable calculations in which large basis sets are used with simpler approximations and small basis sets are paired with more demanding correlation techniques. The performance of several CEP methods, in which diagonal, second-order electron propagator results with large basis sets are combined with higher-order results obtained with smaller basis sets, has been tested for the ionization energies of closed-shell molecules from the G2 set. Useful compromises of accuracy and computational efficiency employ complete-basis-set extrapolation for second-order results and small basis sets in third-order, partial third-order, renormalized partial-third order, or outer valence Green's function calculations. Analysis of results for vertical as well as adiabatic ionization energies leads to specific recommendations on the best use of regular and composite methods. Results for 22 organic molecules of interest in the design of photovoltaic devices, benzo[a]pyrene, Mg-octaethylporphyrin, and C60 illustrate the capabilities of CEP methods for calculations on large molecules.
Composite electron propagator methods for calculating ionization energies.
Díaz-Tinoco, Manuel; Dolgounitcheva, O; Zakrzewski, V G; Ortiz, J V
2016-06-14
Accurate ionization energies of molecules may be determined efficiently with composite electron-propagator (CEP) techniques. These methods estimate the results of a calculation with an advanced correlation method and a large basis set by performing a series of more tractable calculations in which large basis sets are used with simpler approximations and small basis sets are paired with more demanding correlation techniques. The performance of several CEP methods, in which diagonal, second-order electron propagator results with large basis sets are combined with higher-order results obtained with smaller basis sets, has been tested for the ionization energies of closed-shell molecules from the G2 set. Useful compromises of accuracy and computational efficiency employ complete-basis-set extrapolation for second-order results and small basis sets in third-order, partial third-order, renormalized partial-third order, or outer valence Green's function calculations. Analysis of results for vertical as well as adiabatic ionization energies leads to specific recommendations on the best use of regular and composite methods. Results for 22 organic molecules of interest in the design of photovoltaic devices, benzo[a]pyrene, Mg-octaethylporphyrin, and C60 illustrate the capabilities of CEP methods for calculations on large molecules. PMID:27305999
Solar opacity calculations using the super-transition-array method
Krief, M; Gazit, D
2016-01-01
An opacity model based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of local thermodynamic equilibrium plasmas was developed. The model is described and used to calculate spectral opacities for a solar model implementing the recent AGSS09 composition. Calculations are carried throughout the solar radiative zone. The relative contributions of different chemical elements and photon-matter processes to the total Rosseland mean opacity are analyzed in detail. Monochromatic opacities and charge state distributions were compared with the widely used Opacity-Project (OP) code, for several elements near the radiation-convection interface. STA Rosseland opacities for the solar mixture show a very good agreement with OP and the OPAL opacity code, throughout the radiation zone. Finally, an explicit STA calculation of the full AGSS09 photospheric mixture, including all heavy metals was performed. It was shown that due to their extremely low abundance, and despite being very go...
Calculations of EURACOS iron benchmark experiment using the HYBRID method
International Nuclear Information System (INIS)
In this paper, the HYBRID method is used in the calculations of the iron benchmark experiment at the EURACOS-II device. The saturation activities of the 32S(n,p)32P reaction at different depths in an iron block are computed with ENDF/B-IV data to compare with the measurements. At the outer layers of the iron block, the HYBRID calculation gives increasingly higher results than the VITAMIN-C multigroup calculation. With the adjustment of the two- to one-dimensional ratios, the HYBRID results agree with the measurements to within 10% at most penetration depths, a considerable improvement over the VITAMIN-C multigroup results. The development of a collapsing method for the HYBRID cross sections provides a more direct and practical way of using the HYBRID method in the two-dimensional calculations. It is observed that half of the window effect is smeared in the collapsing treatment, but it still provides a better cross-section set than the VITAMIN-C cross sections for the deep-penetration calculations
A method to calculate displacement factors using SVM
Institute of Scientific and Technical Information of China (English)
Li Peixian; Tan Zhixiang; Yan Lili; Deng Kazhong
2011-01-01
In order to improve the precision of mining subsidence prediction,a mathematical model using Support Vector Machine (SVM) was established to calculate the displacement factor.The study is based on a comprehensive analysis of factors affecting the displacement factor,such as mechanical properties of the cover rock,the ratio of mining depth to seam thickness,dip angle of the coal seam and the thickness of loose layer.Data of 63 typical observation stations were used as a training and testing sample set.A SVM regression model of the displacement factor and the factors affecting it was established with a kernel function,an insensitive loss factor and a properly selected penalty factor.Given an accurate calculation algorithm for testing and analysis,the results show that an SVM regression model can calculate displacement factor precisely and reliable precision can be obtained which meets engineering requirements.The experimental results show that the method to calculation of the displacement factor,based on the SVM method,is feasible.The many factors affecting the displacement factor can be considered with this method.The research provides an efficient and accurate approach for the calculation of displacement in mining subsidence prediction.
A New Method to Calculate Internal Rate of Return
Directory of Open Access Journals (Sweden)
azadeh zandi
2015-09-01
Full Text Available A number of methods have been developed to choose the best capital investment projects such as net present value, internal rate of return and etc. Internal rate of return method is probably the most popular method among managers and investors. But despite the popularity there are serious drawbacks and limitations in this method. After decades of efforts made by economists and experts to improve the method and its shortcomings, Magni in 2010 has revealed a new approach that can solves the most of internal rate of return method problems. This paper present a new method which is originated from Magni’s approach but has much more simple calculations and can resolve all the drawbacks of internal rate of return method.
Optimization method for quantitative calculation of clay minerals in soil
Indian Academy of Sciences (India)
Libo Hao; Qiaoqiao Wei; Yuyan Zhao; Zilong Lu; Xinyun Zhao
2015-04-01
Determination of types and amounts for clay minerals in soil are important in environmental, agricultural, and geological investigations. Many reliable methods have been established to identify clay mineral types. However, no reliable method for quantitative analysis of clay minerals has been established so far. In this study, an attempt was made to propose an optimization method for the quantitative determination of clay minerals in soil based on bulk chemical composition data. The fundamental principles and processes of the calculation are elucidated. Some samples were used for reliability verification of the method and the results prove the simplicity and efficacy of the approach.
Investigation of methods used in calculations of solar cell parameters
Shvets, E. Ya.; Khrypko, S. L.; Zubko, E. I.
2009-01-01
Analytical expressions have been obtained for extracting the electrical parameters and characteristics of solar cells, including series and shunt resistances, and the saturation current. The method of Lagrange multipliers was used for computing the shape factor of the current–voltage characteristic (CVC) of solar cell. The calculation results demonstrated a satisfactory agreement with experimental data.
Emergy Algebra: Improving Matrix Methods for Calculating Tranformities
Transformity is one of the core concepts in Energy Systems Theory and it is fundamental to the calculation of emergy. Accurate evaluation of transformities and other emergy per unit values is essential for the broad acceptance, application and further development of emergy method...
Thick-Restart Lanczos Method for Electronic Structure Calculations
International Nuclear Information System (INIS)
This paper describes two recent innovations related to the classic Lanczos method for eigenvalue problems, namely the thick-restart technique and dynamic restarting schemes. Combining these two new techniques we are able to implement an efficient eigenvalue problem solver. This paper will demonstrate its effectiveness on one particular class of problems for which this method is well suited: linear eigenvalue problems generated from non-self-consistent electronic structure calculations
Theories and calculation methods for regional objective ET (evapotranspiration): Applications
Institute of Scientific and Technical Information of China (English)
LIU diaHong; QIN DaYong; WANG MingNa; L(U) JinYan; SANG XueFeng; ZHANG RuiMei
2009-01-01
The regional objective ET (evapotranspiration) is defined as the quantity of water that could be con-sumed in a particular region. It varies with the water conditions and economic development stages in the region. It is also constrained by the requirement of benign environment cycle. At the same time, it must meet the demands of sustainable economic growth and the construction of harmony society.Objective ET based water resources distribution will replace the conventional method, which empha-sizes the balance between the water demand and the water supply. It puts focus on the reasonable water consumption instead of the forecasted water demand, which is usually greater than the actual one. In this paper, we calculated the objective ET of 2010 year level in Tianjin by an analysis-integra-tion-assessment method. Objective ET can be classified into two parts: controllable ET and uncontrol-lable ET. Controllable ET includes the ET from irrigation land and the ET from resident land, among which the former can be calculated with soil moisture model and evapotranspiration model, while the latter can be calculated by water use ration and water consumption rate. The uncontrollable ET can be calculated with the distributed hydrological model and the remote sensing monitoring model. The two models can be mutually calibrated. In this paper, eight schemes are put forward based on different portfolios of water resources. The objective ET of each scheme was calculated and the results were assessed and analyzed. Finally, an optimal scheme was recommended.
Studies on the calculation method of regional solar radiation
International Nuclear Information System (INIS)
Studies on the Calculation Method of Regional Solar Radiation 1. The significance and question of regional solar radiation The significance of regional solar radiation in agriculture is clear. To estimate regional agricultural producing potential, we need to know the regional solar radiation. In the field of hydrology, regional solar radiation is also important to estimate evapotranspiration of the region. There are so many slopes with different slope angles and slope directions in a region. So, we have to know how we can calculate slope radiation. The conversion
Load calculation methods for offshore wind turbine foundations
DEFF Research Database (Denmark)
Passon, Patrik; Branner, Kim
2014-01-01
turbine manufacturer provides the FD with dynamic responses obtained from aeroelastic simulations at a predefined interface. These responses are subsequently expanded to the corresponding dynamic responses in all structural parts of the foundation. In this article, a novel load calculation method, for the......Calculation of design loads for offshore wind turbine (OWT) foundations is typically performed in a joint effort between wind turbine manufactures and foundation designers (FDs). Ideally, both parties would apply the same fully integrated design tool and model for that purpose. However, such...
Slab Storage Calculation Method for Continuous Casting-Hot Rolling
Institute of Scientific and Technical Information of China (English)
PENG Qi-chun; LIU Qing; TIAN Nai-yuan
2004-01-01
Based on load-oriented manufacturing control theory, different combining modes and slab storage calculation method for continuous casting and hot rolling were discussed. The buffer capacity index of continuous casting-rolling was introduced, and the reasonable slab storage under different combining modes was calculated with buffer capacity index of 120.00 h for CCR, 79.20 h for HCR, 19.68 h for DHCR and 3.84 h for DR. Thin slab is 1.20 h, and the strip is zero. Theory gist was provided for steel enterprise to decrease storage.
A new method for the automatic calculation of prosody
International Nuclear Information System (INIS)
An algorithm is presented for the calculation of the prosodic parameters for speech synthesis. It uses the melodic patterns, composed of rising and falling slopes, suggested by G. CAELEN, and rests on: 1. An analysis into units of meaning to determine a melodic pattern 2. the calculation of the numeric values for the prosodic variations of each syllable; 3. The use of a table of vocalic values for the three parameters for each vowel according to the consonantal environment and of a table of standard duration for consonants. This method was applied in the 'SARA' program of synthesis with satisfactory results. (author)
Short circuit currents calculation by using the impedance correction method
Energy Technology Data Exchange (ETDEWEB)
Schaefer, W.
1985-01-01
By introduction of correction factors for the impedances of generators and power station unit transformers into the known guidings according to VDE 0102 (basis principle of short circuit current calculation) it is possible to limit the deviation to less then +-5% of the value of the complete superposition method apart from some exceptions. The correction factors are valid for calculation of the maximum short circuit currents considering the practically admissible operating conditions. The separated correction of the impedances of generators and power station unit transformers can be used without restriction for all short circuit points of interest.
Simplified method for trace anomaly calculations in d≤6
International Nuclear Information System (INIS)
We discuss a simplified method for computing trace anomalies in dimensions d≤6. It is known that in the quantum mechanical approach trace anomalies in d dimensions are given by a (d/2+1)-loop computation in an auxiliary 1D sigma model with arbitrary geometry. We show how one can obtain the same information using a simpler (d/2)-loop calculation on an arbitrary geometry supplemented by a (d/2+1)-loop calculation on the simplified geometry of a maximally symmetric space
Refinement of the substructure method for integral transport calculations
International Nuclear Information System (INIS)
A new generalization of the interface-current method for coupling two-dimensional heterogeneous assemblies, called substructures, has been developed. The method has been designed for fine-structure burnup calculations in large, very heterogeneous media. For the calculations, the medium is divided into rectangular substructures, which can have internal symmetries, containing rectangular and/or cylindrical structure elements, divided into homogeneous zones. A zonewise flat or linear expansion is used to formulate a direct collision-probability problem within each substructure. The substructures are coupled by making a piecewise uniform or linear expansion for the partial currents entering and leaving the substructures. The method has also been used to implement an approximate piecewise isotropic reflection for two-dimensional x-y collision probabilities calculations. The accuracies and computing times achieved are illustrated by one-group fixed-source numerical calculations for a typical 7 x 7 pin pressurized water reactor assembly as well as for a set of fuel slabs imbedded in a water moderator
Calculation of interface curvature with the level-set method
Lervåg, Karl Yngve
2014-01-01
The level-set method is a popular method for interface capturing. One of the advantages of the level-set method is that the curvature and the normal vector of the interface can be readily calculated from the level-set function. However, in cases where the level-set method is used to capture topological changes, the standard discretization techniques for the curvature and the normal vector do not work properly. This is because they are affected by the discontinuities of the signed-distance function half-way between two interfaces. This article addresses the calculation of normal vectors and curvatures with the level-set method for such cases. It presents a discretization scheme that is relatively easy to implement in to an existing code. The improved discretization scheme is compared with a standard discretization scheme, first for a case with no flow, then for a case where two drops collide in a shear flow. The results show that the improved discretization yields more robust calculations in areas where topolo...
Accelerating molecular property calculations with nonorthonormal Krylov space methods
Furche, Filipp; Krull, Brandon T.; Nguyen, Brian D.; Kwon, Jake
2016-05-01
We formulate Krylov space methods for large eigenvalue problems and linear equation systems that take advantage of decreasing residual norms to reduce the cost of matrix-vector multiplication. The residuals are used as subspace basis without prior orthonormalization, which leads to generalized eigenvalue problems or linear equation systems on the Krylov space. These nonorthonormal Krylov space (nKs) algorithms are favorable for large matrices with irregular sparsity patterns whose elements are computed on the fly, because fewer operations are necessary as the residual norm decreases as compared to the conventional method, while errors in the desired eigenpairs and solution vectors remain small. We consider real symmetric and symplectic eigenvalue problems as well as linear equation systems and Sylvester equations as they appear in configuration interaction and response theory. The nKs method can be implemented in existing electronic structure codes with minor modifications and yields speed-ups of 1.2-1.8 in typical time-dependent Hartree-Fock and density functional applications without accuracy loss. The algorithm can compute entire linear subspaces simultaneously which benefits electronic spectra and force constant calculations requiring many eigenpairs or solution vectors. The nKs approach is related to difference density methods in electronic ground state calculations and particularly efficient for integral direct computations of exchange-type contractions. By combination with resolution-of-the-identity methods for Coulomb contractions, three- to fivefold speed-ups of hybrid time-dependent density functional excited state and response calculations are achieved.
An economical method to calculate eigenvalues of the Schroedinger equation
International Nuclear Information System (INIS)
A method is presented which is an extension to negative energies of a spectral integral equation method to solve the Schroedinger equation, developed previously for scattering applications. One important innovation is a re-scaling procedure in order to compensate for the exponential behaviour of the negative energy Green's function. Another is the need to find approximate energy eigenvalues, to serve as starting values for a subsequent iteration procedure. In order to illustrate the new method, the binding energy of the He-He dimer is calculated, using the He-He TTY potential. In view of the small value of the binding energy, the wavefunction has to be calculated to a distance of 3000 au. Two hundred and twenty mesh points were sufficient to obtain an accuracy of three significant figures for the binding energy, and with 320 mesh points the accuracy increased to six significant figures. An application to a potential with two wells, separated by a barrier, is also made
Calculation of Turbulent Boundary Layers Using the Dissipation Integral Method
Institute of Scientific and Technical Information of China (English)
MatthiasBuschmann
1999-01-01
This paper gives an introduction into the dissipation integral method.The general integral equations for the three-dimensional case are derved.It is found that for a practical calculation algorithm the integral monentum equation and the integral energy equation are msot useful.Using Two different sets of mean velocity profiles the hyperbolical character of a dissipation integral method is shown.Test cases for two-and three-dimensional boundary layers are analysed and discussed.The paper concludes with a discussion of the advantages and limits of dissipation integral methods.
Analytical methods to calculate correlation functions in quantum statistical physics
International Nuclear Information System (INIS)
In the work there is presented a brief but clear and quite reserved account of two analytical methods to calculate correlation functions in quantum statistical physics, proceeding from the first principles, i.e., the most broadly used at present two-time temperature Green's functions method and a new, so-called 'direct algebraic' method (DAM). The aim of this work is to show on the concrete examples of live the most broadly used models of quantum statistical physics, mathematical and technical clarity and simplicity of DAM and hence its practical value
Comparison between calculation methods of dose rates in gynecologic brachytherapy
International Nuclear Information System (INIS)
In treatments with radiations for gynecologic tumors is necessary to evaluate the quality of the results obtained by different calculation methods for the dose rates on the points of clinical interest (A, rectal, vesicle). The present work compares the results obtained by two methods. The Manual Calibration Method (MCM) tri dimensional (Vianello E., et.al. 1998), using orthogonal radiographs for each patient in treatment, and the Theraplan/T P-11 planning system (Thratonics International Limited 1990) this last one verified experimentally (Vianello et.al. 1996). The results show that MCM can be used in the physical-clinical practice with a percentile difference comparable at the computerized programs. (Author)
Artificial Boundary Method for Calculating Ship Wave Resistance
Institute of Scientific and Technical Information of China (English)
文新; 韩厚德
2003-01-01
The calculation of wave resistance for a ship moving at constant speed near a free surface is considered. This wave resistance is calculated with a linearized steady potential model. To deal with the unboundedness of the physical domain in the potential flow problem, we introduce one vertical side as an artificial upstream boundary and two vertical sides as the artificial downstream boundaries. On the artificial boundaries, a sequence of high-order global artificial boundary conditions are given. Then the potential flow problem is reduced to a problem defined on a finite computational domain, which is equivalent to a variational problem. The solution of the variational problem by the finite element method gives the numerical approximation of the potential flow around the ship, which was used to calculate the wave resistance. The numerical examples show the accuracy and efficiency of the proposed numerical scheme.
The application of advanced rotor (performance) methods for design calculations
Energy Technology Data Exchange (ETDEWEB)
Bussel, G.J.W. van [Delft Univ. of Technology, Inst. for Wind Energy, Delft (Netherlands)
1997-08-01
The calculation of loads and performance of wind turbine rotors has been a topic for research over the last century. The principles for the calculation of loads on rotor blades with a given specific geometry, as well as the development of optimal shaped rotor blades have been published in the decades that significant aircraft development took place. Nowadays advanced computer codes are used for specific problems regarding modern aircraft, and application to wind turbine rotors has also been performed occasionally. The engineers designing rotor blades for wind turbines still use methods based upon global principles developed in the beginning of the century. The question what to expect in terms of the type of methods to be applied in a design environment for the near future is addressed here. (EG) 14 refs.
Implicit calculations of transonic flows using monotone methods
Goorjian, P. M.; van Buskirk, R.
1981-01-01
Implicit approximate-factorization algorithms have been developed that use monotone methods for the calculation of steady and unsteady transonic flows governed by the small-disturbance-potential equation. These algorithms use the new Engquist-Osher switch in the type-dependent differencing in place of the standard Murman-Cole switch. The resulting algorithms are more stable; hence, calculations can be done more efficiently. For steady flows, the convergence rate is about 35% faster, and for unsteady flows the allowable time step is about 10 times larger. These improvements are achieved with no increase in computer storage and with only minor modifications in codes that use the Murman-Cole switch. Also an implicit algorithm has been developed for the steady full-potential equation in one-dimension, which uses monotone methods.
Methods and computer codes for nuclear systems calculations
Indian Academy of Sciences (India)
B P Kochurov; A P Knyazev; A Yu Kwaretzkheli
2007-02-01
Some numerical methods for reactor cell, sub-critical systems and 3D models of nuclear reactors are presented. The methods are developed for steady states and space–time calculations. Computer code TRIFON solves space-energy problem in (, ) systems of finite height and calculates heterogeneous few-group matrix parameters of reactor cells. These parameters are used as input data in the computer code SHERHAN solving the 3D heterogeneous reactor equation for steady states and 3D space–time neutron processes simulation. Modification of TRIFON was developed for the simulation of space–time processes in sub-critical systems with external sources. An option of SHERHAN code for the system with external sources is under development.
Problems in radiation shielding calculations with Monte Carlo methods
International Nuclear Information System (INIS)
The Monte Carlo method is a very useful tool for solving a large class of radiation transport problem. In contrast with deterministic method, geometric complexity is a much less significant problem for Monte Carlo calculations. However, the accuracy of Monte Carlo calculations is of course, limited by statistical error of the quantities to be estimated. In this report, we point out some typical problems to solve a large shielding system including radiation streaming. The Monte Carlo coupling technique was developed to settle such a shielding problem accurately. However, the variance of the Monte Carlo results using the coupling technique of which detectors were located outside the radiation streaming, was still not enough. So as to bring on more accurate results for the detectors located outside the streaming and also for a multi-legged-duct streaming problem, a practicable way of ''Prism Scattering technique'' is proposed in the study. (author)
Helicity methods in LO and NLO QCD calculations
International Nuclear Information System (INIS)
The goal of this thesis is the acceleration of numerical calculations of QCD observables, both at leading order and next-to-leading order in the coupling constant. In particular, the optimization of helicity and spin summation in the context of VEGAS Monte Carlo algorithms is investigated. In the literature, two such methods are mentioned but without detailed analyses. Only one of these methods can be used at next-to-leading order. This work presents a total of five different methods that replace the helicity sums with a Monte Carlo integration. This integration can be combined with the existing phase space integral, in the hope that this causes less overhead than the complete summation. For three of these methods, an extension to existing subtraction terms is developed which is required to enable next-to-leading order calculations. All methods are analyzed with respect to efficiency, accuracy, and ease of implementation before they are compared with each other. In this process, one method shows clear advantages in relation to all others.
Benchmark calculations for evaluation methods of gas volumetric leakage rate
International Nuclear Information System (INIS)
A containment function of radioactive materials transport casks is essential for safe transportation to prevent the radioactive materials from being released into environment. Regulations such as IAEA standard determined the limit of radioactivity to be released. Since is not practical for the leakage tests to measure directly the radioactivity release from a package, as gas volumetric leakages rates are proposed in ANSI N14.5 and ISO standards. In our previous works, gas volumetric leakage rates for several kinds of gas from various leaks were measured and two evaluation methods, 'a simple evaluation method' and 'a strict evaluation method', were proposed based on the results. The simple evaluation method considers the friction loss of laminar flow with expansion effect. The strict evaluating method considers an exit loss in addition to the friction loss. In this study, four worked examples were completed for on assumed large spent fuel transport cask (Type B Package) with wet or dry capacity and at three transport conditions; normal transport with intact fuels or failed fuels, and an accident in transport. The standard leakage rates and criteria for two kinds of leak test were calculated for each example by each evaluation method. The following observations are made based upon the calculations and evaluations: the choked flow model of ANSI method greatly overestimates the criteria for tests ; the laminar flow models of both ANSI and ISO methods slightly overestimate the criteria for tests; the above two results are within the design margin for ordinary transport condition and all methods are useful for the evaluation; for severe condition such as failed fuel transportation, it should pay attention to apply a choked flow model of ANSI method. (authors)
Testing the QA Method for Calculating Jet v_{2}
Mueller, Jason
2014-01-01
For the summer, I was assigned to work on the ALICE experiment with Alice Ohlson. I wrote several programs throughout the summer that were used to calculate jet v 2 using a non-standard method described by my supervisor in her Ph.D. thesis. Though the project is not yet complete, significant progress has been made, and the results so far seem promising.
Calculations of pair production by Monte Carlo methods
International Nuclear Information System (INIS)
We describe some of the technical design issues associated with the production of particle-antiparticle pairs in very large accelerators. To answer these questions requires extensive calculation of Feynman diagrams, in effect multi-dimensional integrals, which we evaluate by Monte Carlo methods on a variety of supercomputers. We present some portable algorithms for generating random numbers on vector and parallel architecture machines. 12 refs., 14 figs
Calculations of pair production by Monte Carlo methods
Energy Technology Data Exchange (ETDEWEB)
Bottcher, C.; Strayer, M.R.
1991-01-01
We describe some of the technical design issues associated with the production of particle-antiparticle pairs in very large accelerators. To answer these questions requires extensive calculation of Feynman diagrams, in effect multi-dimensional integrals, which we evaluate by Monte Carlo methods on a variety of supercomputers. We present some portable algorithms for generating random numbers on vector and parallel architecture machines. 12 refs., 14 figs.
The New Performance Calculation Method of Fouled Axial Flow Compressor
Huadong Yang; Hong Xu
2014-01-01
Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section in...
Fast Stiffness Matrix Calculation for Nonlinear Finite Element Method
Directory of Open Access Journals (Sweden)
Emir Gülümser
2014-01-01
Full Text Available We propose a fast stiffness matrix calculation technique for nonlinear finite element method (FEM. Nonlinear stiffness matrices are constructed using Green-Lagrange strains, which are derived from infinitesimal strains by adding the nonlinear terms discarded from small deformations. We implemented a linear and a nonlinear finite element method with the same material properties to examine the differences between them. We verified our nonlinear formulation with different applications and achieved considerable speedups in solving the system of equations using our nonlinear FEM compared to a state-of-the-art nonlinear FEM.
Methods for calculating conjugate problems of heat transfer
Kalinin, E. K.; Dreitser, G. A.; Kostiuk, V. V.; Berlin, I. I.
Methods are examined for calculating various conjugate problems of heat transfer in channels and closed vessels in cases of single-phase and two-phase flow in steady and unsteady conditions. The single-phase-flow studies involve the investigation of gaseous and liquid heat-carriers in pipes, annular and plane channels, and pipe bundles in cases of cooling and heating. General relationships are presented for heat transfer in cases of film, transition, and nucleate boiling, as well as for boiling crises. Attention is given to methods for analyzing the filling and cooling of conduits and tanks by cryogenic liquids; and ways to intensify heat transfer in these conditions are examined.
Unfolding method for first-principles LCAO electronic structure calculations
Lee, Chi-Cheng; Yamada-Takamura, Yukiko; Ozaki, Taisuke
2013-08-01
Unfolding the band structure of a supercell to a normal cell enables us to investigate how symmetry breakers such as surfaces and impurities perturb the band structure of the normal cell. We generalize the unfolding method, originally developed based on Wannier functions, to the linear combination of atomic orbitals (LCAO) method, and present a general formula to calculate the unfolded spectral weight. The LCAO basis set is ideal for the unfolding method because the basis functions allocated to each atomic species are invariant regardless of the existence of surface and impurity. The unfolded spectral weight is well defined by the property of the LCAO basis functions. In exchange for the property, the non-orthogonality of the LCAO basis functions has to be taken into account. We show how the non-orthogonality can be properly incorporated in the general formula. As an illustration of the method, we calculate the dispersive quantized spectral weight of a ZrB2 slab and show strong spectral broadening in the out-of-plane direction, demonstrating the usefulness of the unfolding method.
Unfolding method for first-principles LCAO electronic structure calculations
International Nuclear Information System (INIS)
Unfolding the band structure of a supercell to a normal cell enables us to investigate how symmetry breakers such as surfaces and impurities perturb the band structure of the normal cell. We generalize the unfolding method, originally developed based on Wannier functions, to the linear combination of atomic orbitals (LCAO) method, and present a general formula to calculate the unfolded spectral weight. The LCAO basis set is ideal for the unfolding method because the basis functions allocated to each atomic species are invariant regardless of the existence of surface and impurity. The unfolded spectral weight is well defined by the property of the LCAO basis functions. In exchange for the property, the non-orthogonality of the LCAO basis functions has to be taken into account. We show how the non-orthogonality can be properly incorporated in the general formula. As an illustration of the method, we calculate the dispersive quantized spectral weight of a ZrB2 slab and show strong spectral broadening in the out-of-plane direction, demonstrating the usefulness of the unfolding method. (paper)
Comparison of dose calculation methods for brachytherapy of intraocular tumors
Energy Technology Data Exchange (ETDEWEB)
Rivard, Mark J.; Chiu-Tsao, Sou-Tung; Finger, Paul T.; Meigooni, Ali S.; Melhus, Christopher S.; Mourtada, Firas; Napolitano, Mary E.; Rogers, D. W. O.; Thomson, Rowan M.; Nath, Ravinder [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Quality MediPhys LLC, Denville, New Jersey 07834 (United States); New York Eye Cancer Center, New York, New York 10065 (United States); Department of Radiation Oncology, Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Department of Radiation Physics, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States) and Department of Experimental Diagnostic Imaging, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Physics, Elekta Inc., Norcross, Georgia 30092 (United States); Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520 (United States)
2011-01-15
Purpose: To investigate dosimetric differences among several clinical treatment planning systems (TPS) and Monte Carlo (MC) codes for brachytherapy of intraocular tumors using {sup 125}I or {sup 103}Pd plaques, and to evaluate the impact on the prescription dose of the adoption of MC codes and certain versions of a TPS (Plaque Simulator with optional modules). Methods: Three clinical brachytherapy TPS capable of intraocular brachytherapy treatment planning and two MC codes were compared. The TPS investigated were Pinnacle v8.0dp1, BrachyVision v8.1, and Plaque Simulator v5.3.9, all of which use the AAPM TG-43 formalism in water. The Plaque Simulator software can also handle some correction factors from MC simulations. The MC codes used are MCNP5 v1.40 and BrachyDose/EGSnrc. Using these TPS and MC codes, three types of calculations were performed: homogeneous medium with point sources (for the TPS only, using the 1D TG-43 dose calculation formalism); homogeneous medium with line sources (TPS with 2D TG-43 dose calculation formalism and MC codes); and plaque heterogeneity-corrected line sources (Plaque Simulator with modified 2D TG-43 dose calculation formalism and MC codes). Comparisons were made of doses calculated at points-of-interest on the plaque central-axis and at off-axis points of clinical interest within a standardized model of the right eye. Results: For the homogeneous water medium case, agreement was within {approx}2% for the point- and line-source models when comparing between TPS and between TPS and MC codes, respectively. For the heterogeneous medium case, dose differences (as calculated using the MC codes and Plaque Simulator) differ by up to 37% on the central-axis in comparison to the homogeneous water calculations. A prescription dose of 85 Gy at 5 mm depth based on calculations in a homogeneous medium delivers 76 Gy and 67 Gy for specific {sup 125}I and {sup 103}Pd sources, respectively, when accounting for COMS-plaque heterogeneities. For off
Solar Opacity Calculations Using the Super-transition-array Method
Krief, M.; Feigel, A.; Gazit, D.
2016-04-01
A new opacity model has been developed based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of plasmas in local thermodynamic equilibrium. The atomic code, named STAR (STA-Revised), is described and used to calculate spectral opacities for a solar model implementing the recent AGSS09 composition. Calculations are carried out throughout the solar radiative zone. The relative contributions of different chemical elements and atomic processes to the total Rosseland mean opacity are analyzed in detail. Monochromatic opacities and charge-state distributions are compared with the widely used Opacity Project (OP) code, for several elements near the radiation–convection interface. STAR Rosseland opacities for the solar mixture show a very good agreement with OP and the OPAL opacity code throughout the radiation zone. Finally, an explicit STA calculation was performed of the full AGSS09 photospheric mixture, including all heavy metals. It was shown that, due to their extremely low abundance, and despite being very good photon absorbers, the heavy elements do not affect the Rosseland opacity.
Investigations on the Migration Mode Method (MMM) for reactor calculations
International Nuclear Information System (INIS)
Current calculation codes for reactor analysis are based on the multi-group method to evaluate energy distribution of neutron flux. Usually a two energy group diffusion equation is adopted. This choice is adequate for PWRs associated to cross sections libraries tabulated versus fuel exposure and other state parameters as moderator density, fuel temperature, boron concentration. An improvement of this approach is represented by the Migration Mode Method (MMM) by which the neutron spectrum is expanded in terms of base functions corresponding to the different modes of migration of the neutrons in the energy dimension. For a thermal reactor, three such functions may be easily identified: the Maxwellian distribution of the neutrons at thermal equilibrium with the moderator, the 1/E slowing down distribution (corrected to take into account resonance absorption effects) and the fission neutron spectrum. The (space-dependent) coefficients of the expansion are calculated by solving a differential equation which results having a structure similar to the one relevant to multi-group theory. The method can therefore be easily implemented adopting existing diffusion theory codes. With the present work, some investigations on the MMM are described relevant to UO2 fuelled PWR systems. Demonstrative results are given to validate the potentiality of the method. (authors)
Investigations on the migration mode method (MMM) for reactor calculations
International Nuclear Information System (INIS)
Current calculation codes for reactor analysis are based on the multi-group method to evaluate energy distribution of neutron flux. Usually a two energy group diffusion equation is adopted. This choice is adequate for PWRs associated to cross sections libraries tabulated versus fuel exposure and other state parameters as moderator density, fuel temperature, boron concentration. An improvement of this approach is represented by the migration mode method (MMM) by which the neutron spectrum is expanded in terms of base functions corresponding to the different modes of migration of the neutrons in the energy dimension. For a thermal reactor, three such functions may be easily identified: the Maxwellian distribution of the neutrons at thermal equilibrium with the moderator, the 1/E slowing down distribution (corrected to take into account resonance absorption effects) and the fission neutron spectrum. The (space-dependent) coefficients of the expansion are calculated by solving a differential equation which results having a structure similar to the one relevant to multi-group theory. The method can therefore be easily implemented adopting existing diffusion theory codes. With the present work, some investigations on the MMM are described relevant to UO2 fuelled PWR systems. Demonstrative results are given to validate the potentiality of the method
The new performance calculation method of fouled axial flow compressor.
Yang, Huadong; Xu, Hong
2014-01-01
Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds' law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail. PMID:25197717
The New Performance Calculation Method of Fouled Axial Flow Compressor
Directory of Open Access Journals (Sweden)
Huadong Yang
2014-01-01
Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.
Investigations on the migration mode method (MMM) for reactor calculations
Energy Technology Data Exchange (ETDEWEB)
Dall' Osso, Aldo [AREVA NP, Tour Areva, 92084 Paris La Defense Cedex (France); Gandini, Augusto [DINCE, University of Rome ' La Sapienza' , Piazzale Aldo Moro 5, 00185 Rome (Italy)], E-mail: augusto.gandini@uniroma1.it; Rotella, Rossella [S.R.S. GROUP S.r.l., Via dei Prefetti 26, 00186 Rome (Italy)
2008-07-15
Current calculation codes for reactor analysis are based on the multi-group method to evaluate energy distribution of neutron flux. Usually a two energy group diffusion equation is adopted. This choice is adequate for PWRs associated to cross sections libraries tabulated versus fuel exposure and other state parameters as moderator density, fuel temperature, boron concentration. An improvement of this approach is represented by the migration mode method (MMM) by which the neutron spectrum is expanded in terms of base functions corresponding to the different modes of migration of the neutrons in the energy dimension. For a thermal reactor, three such functions may be easily identified: the Maxwellian distribution of the neutrons at thermal equilibrium with the moderator, the 1/E slowing down distribution (corrected to take into account resonance absorption effects) and the fission neutron spectrum. The (space-dependent) coefficients of the expansion are calculated by solving a differential equation which results having a structure similar to the one relevant to multi-group theory. The method can therefore be easily implemented adopting existing diffusion theory codes. With the present work, some investigations on the MMM are described relevant to UO{sub 2} fuelled PWR systems. Demonstrative results are given to validate the potentiality of the method.
Convergence and accuracy of numerical methods for trajectory calculations
International Nuclear Information System (INIS)
Computation of trajectories by a kinematic method requires the numerical solution of the differential equation by which the trajectory is defined. A widely used method is the iterative scheme of Petterssen which has second-order accuracy. The convergence and accuracy of this scheme is investigated for some simple flow types where analytical solutions are available. The results are discussed in comparison to other methods, especially a method similar to the Patterssen scheme, which has been recommended for use in semi-Lagrangian advection schemes. The truncation error in trajectory calculations should be kept about one order of magnitude smaller than the total uncertainty, which is mainly due to analysis errors and limited resolution of the wind data. It is shown that for trajectory calculations based on the typical output of current numerical weather prediction models or comparable data, this requires a time step 15% of the time step necessary to achieve convergence. If a fixed time step is used, it should not exceed about 0.5 h. Flexible time steps, based on the estimate of the truncation error which is provided by the difference between the first and the second iteration, are an attractive alternative. 26 refs., 8 figs
Calculation of VPP basing on functional analyzing method
Institute of Scientific and Technical Information of China (English)
Bai Kaixiang; Wang Dexun; Han Jiurui
2007-01-01
The establishment and realization of the VPP calucation's model for the functional analytic theory are discussed in this paper. Functional analyzing method is a theoretical model of the VPP calculation which can eliminate the influence of the sail and board's size skillfully, so it can be regarded as a brief standard of the sailboard's VPP results. As a brief watery dynamical model, resistance on board can be regarded as a direct proportion to the square of the boat-velocity. The boat-velocities at the state of six wind-velocities (3 m/s-8 m/s) with angles of 25°-180° are obtained by calculating, which provides an important gist of the sailing-route's selection in upwind-sailing.
Calculation method of solar radiation incident upon slopes considering topography
International Nuclear Information System (INIS)
When radiation in a basin is calculated, slope inclination, slope orientation and topography of surroundings have to be taken into account. The method of approximation to topography by triangles proposed by Miura et al. is employed to take slope characteristics and topography of surroundings into account. Authors prepared 360 directions' shades altitudes, i.e. every degree of angle, for each triangle in advance, and used these shades' altitudes to calculate both direct radiation on a slope diffuse radiation taking topography of surroundings into account. And authors show how to estimate hourly direct and diffuse solar radiation from hourly horizontal global radiation and synthesize hourly slope global radiation on slopes
Large-scale atomic calculations using variational methods
Energy Technology Data Exchange (ETDEWEB)
Joensson, Per
1995-01-01
Atomic properties, such as radiative lifetimes, hyperfine structures and isotope shift, have been studied both theoretically and experimentally. Computer programs which calculate these properties from multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) wave functions have been developed and tested. To study relativistic effects, a program which calculates hyperfine structures from multiconfiguration Dirac-Fock (MCDF) wave functions has also been written. A new method of dealing with radial non-orthogonalities in transition matrix elements has been investigated. This method allows two separate orbital sets to be used for the initial and final states, respectively. It is shown that, once the usual orthogonality restrictions have been overcome, systematic MCHF calculations are able to predict oscillator strengths in light atoms with high accuracy. In connection with recent high-power laser experiments, time-dependent calculations of the atomic response to intense laser fields have been performed. Using the frozen-core approximation, where the atom is modeled as an active electron moving in the average field of the core electrons and the nucleus, the active electron has been propagated in time under the influence of the laser field. Radiative lifetimes and hyperfine structures of excited states in sodium and silver have been experimentally determined using time-resolved laser spectroscopy. By recording the fluorescence light decay following laser excitation in the vacuum ultraviolet spectral region, the radiative lifetimes and hyperfine structures of the 7p{sup 2}P states in silver have been measured. The delayed-coincidence technique has been used to make very accurate measurements of the radiative lifetimes and hyperfine structures of the lowest 2P states in sodium and silver. 77 refs, 2 figs, 14 tabs.
Large-scale atomic calculations using variational methods
International Nuclear Information System (INIS)
Atomic properties, such as radiative lifetimes, hyperfine structures and isotope shift, have been studied both theoretically and experimentally. Computer programs which calculate these properties from multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) wave functions have been developed and tested. To study relativistic effects, a program which calculates hyperfine structures from multiconfiguration Dirac-Fock (MCDF) wave functions has also been written. A new method of dealing with radial non-orthogonalities in transition matrix elements has been investigated. This method allows two separate orbital sets to be used for the initial and final states, respectively. It is shown that, once the usual orthogonality restrictions have been overcome, systematic MCHF calculations are able to predict oscillator strengths in light atoms with high accuracy. In connection with recent high-power laser experiments, time-dependent calculations of the atomic response to intense laser fields have been performed. Using the frozen-core approximation, where the atom is modeled as an active electron moving in the average field of the core electrons and the nucleus, the active electron has been propagated in time under the influence of the laser field. Radiative lifetimes and hyperfine structures of excited states in sodium and silver have been experimentally determined using time-resolved laser spectroscopy. By recording the fluorescence light decay following laser excitation in the vacuum ultraviolet spectral region, the radiative lifetimes and hyperfine structures of the 7p2P states in silver have been measured. The delayed-coincidence technique has been used to make very accurate measurements of the radiative lifetimes and hyperfine structures of the lowest 2P states in sodium and silver. 77 refs, 2 figs, 14 tabs
A unique manual method for emergency offsite dose calculations
International Nuclear Information System (INIS)
This paper describes a manual method developed for performance of emergency offsite dose calculations for PP and L's Susquehanna Steam Electric Station. The method is based on a three-part carbonless form. The front page guides the user through selection of the appropriate accident case and inclusion of meteorological and effluent data data. By circling the applicable accident descriptors, the user circles the dose factors on pages 2 and 3 which are then simply multiplied to yield the whole body and thyroid dose rates at the plant boundary, two, five, and ten miles. The process used to generate the worksheet is discussed, including the method used to incorporate the observed terrain effects on airflow patterns caused by the Susquehanna River Valley topography
Nested element method in multidimensional neutron diffusion calculations
International Nuclear Information System (INIS)
A new numerical method is developed that is particularly efficient in solving the multidimensional neutron diffusion equation in geometrically complex systems. The needs for a generally applicable and fast running computer code have stimulated, here presented, the inroad of a nonclassical (R-function) numerical method into the nuclear field. By using the R-functions, the geometrical components of the diffusion problem are a priory analytically implemented into the approximate solution. The class of functions, to which the approximate solution belongs, is chosen as close to the exact solution class as practically acceptable from the time consumption point of view. That implies a drastic reduction of the number of degrees of freedom, compared to the other methods. Furthermore, the reduced number of degrees of freedom enables calculation of large multidimensional problems on small computers
Nested element method in multidimensional neutron diffusion calculations
International Nuclear Information System (INIS)
A new numerical method is developed that is particularly efficient in solving the multidimensional neutron diffusion equation in geometrically complex systems. The needs for a generally applicable and fast running computer code have stimulated the inroad of a nonclassical (R-function) numerical method into the nuclear field. By using the R-functions, the geometrical components of the diffusion problem are a priori analytically implemented into the approximate solution. The class of functions, to which the approximate solution belongs, is chosen as close to the exact solution class as practically acceptable from the time consumption point of view. That implies a drastic reduction of the number of degrees of freedom, compared to the other methods. Furthermore, the reduced number of degrees of freedom enables calculation of large multidimensional problems on small computers
Large Scale Electronic Structure Calculations using Quantum Chemistry Methods
Scuseria, Gustavo E.
1998-03-01
This talk will address our recent efforts in developing fast, linear scaling electronic structure methods for large scale applications. Of special importance is our fast multipole method( M. C. Strain, G. E. Scuseria, and M. J. Frisch, Science 271), 51 (1996). (FMM) for achieving linear scaling for the quantum Coulomb problem (GvFMM), the traditional bottleneck in quantum chemistry calculations based on Gaussian orbitals. Fast quadratures(R. E. Stratmann, G. E. Scuseria, and M. J. Frisch, Chem. Phys. Lett. 257), 213 (1996). combined with methods that avoid the Hamiltonian diagonalization( J. M. Millam and G. E. Scuseria, J. Chem. Phys. 106), 5569 (1997) have resulted in density functional theory (DFT) programs that can be applied to systems containing many hundreds of atoms and ---depending on computational resources or level of theory-- to many thousands of atoms.( A. D. Daniels, J. M. Millam and G. E. Scuseria, J. Chem. Phys. 107), 425 (1997). Three solutions for the diagonalization bottleneck will be analyzed and compared: a conjugate gradient density matrix search (CGDMS), a Hamiltonian polynomial expansion of the density matrix, and a pseudo-diagonalization method. Besides DFT, our near-field exchange method( J. C. Burant, G. E. Scuseria, and M. J. Frisch, J. Chem. Phys. 105), 8969 (1996). for linear scaling Hartree-Fock calculations will be discussed. Based on these improved capabilities, we have also developed programs to obtain vibrational frequencies (via analytic energy second derivatives) and excitation energies (through time-dependent DFT) of large molecules like porphyn or C_70. Our GvFMM has been extended to periodic systems( K. N. Kudin and G. E. Scuseria, Chem. Phys. Lett., in press.) and progress towards a Gaussian-based DFT and HF program for polymers and solids will be reported. Last, we will discuss our progress on a Laplace-transformed \\cal O(N^2) second-order pertubation theory (MP2) method.
Score Calculation in Informatics Contests Using Multiple Criteria Decision Methods
Directory of Open Access Journals (Sweden)
Jurate SKUPIENE
2011-04-01
Full Text Available The Lithuanian Informatics Olympiad is a problem solving contest for high school students. The work of each contestant is evaluated in terms of several criteria, where each criterion is measured according to its own scale (but the same scale for each contestant. Several jury members are involved in the evaluation. This paper analyses the problem how to calculate the aggregated score for whole submission in the above mentioned situation. The chosen methodology for solving this problem is Multiple Criteria Decision Analysis (MCDA. The outcome of this paper is the score aggregation method proposed to be applied in LitIO developed using MCDA approaches.
Dose calculation of 6 MV Truebeam using Monte Carlo method
International Nuclear Information System (INIS)
The purpose of this work is to simulate 6 MV Varian Truebeam linac dosimeter characteristics using Monte Carlo method and to investigate the availability of phase space file and the accuracy of the simulation. With the phase space file at linac window supplied by Varian to be a source, the patient-dependent part was simulated. Dose distributions in a water phantom with a 10 cm × 10 cm field were calculated and compared with measured data for validation. Evident time reduction was obtained from 4-5 h which a whole simulation cost on the same computer to around 48 minutes. Good agreement between simulations and measurements in water was observed. Dose differences are less than 3% for depth doses in build-up region and also for dose profiles inside the 80% field size, and the effect in penumbra is good. It demonstrate that the simulation using existing phase space file as the EGSnrc source is efficient. Dose differences between calculated data and measured data could meet the requirements for dose calculation. (authors)
A CNS calculation line based on a Monte Carlo method
International Nuclear Information System (INIS)
Full text: The design of the moderator cell of a Cold Neutron Source (CNS) involves many different considerations regarding geometry, location, and materials. Decisions taken in this sense affect not only the neutron flux in the source neighborhood, which can be evaluated by a standard empirical method, but also the neutron flux values in experimental positions far away of the neutron source. At long distances from the neutron source, very time consuming 3D deterministic methods or Monte Carlo transport methods are necessary in order to get accurate figures. Standard and typical terminology such as average neutron flux, neutron current, angular flux, luminosity, are magnitudes very difficult to evaluate in positions located several meters away from the neutron source. The Monte Carlo method is a unique and powerful tool to transport neutrons. Its use in a bootstrap scheme appears to be an appropriate solution for this type of systems. The proper use of MCNP as the main tool leads to a fast and reliable method to perform calculations in a relatively short time with low statistical errors. The design goal is to evaluate the performance of the neutron sources, their beam tubes and neutron guides at specific experimental locations in the reactor hall as well as in the neutron or experimental hall. In this work, the calculation methodology used to design Cold, Thermal and Hot Neutron Sources and their associated Neutron Beam Transport Systems, based on the use of the MCNP code, is presented. This work also presents some changes made to the cross section libraries in order to cope with cryogenic moderators such as liquid hydrogen and liquid deuterium. (author)
Study on calculation methods for the effective delayed neutron fraction
International Nuclear Information System (INIS)
The effective delayed neutron fraction βeff is one of the important neutronic parameters from a view point of a reactor kinetics. Several Monte-Carlo-based methods to estimate βeff have been proposed to date. In order to quantify the accuracy of these methods, we study calculation methods for βeff by analyzing various fast neutron systems including the bare spherical systems (Godiva, Jezebel, Skidoo, Jezebel-240), the reflective spherical systems (Popsy, Topsy, Flattop-23), MASURCA-R2 and MASURCA-ZONA2, and FCA XIX-1, XIX-2 and XIX-3. These analyses are performed by using SLAROM-UF and CBG for the deterministic method and MVP-II for the Monte Carlo method. We calculate βeff with various definitions such as the fundamental value β0, the standard definition, Nauchi's definition and Meulekamp's definition, and compare these results with each other. Through the present study, we find the following: The largest difference among the standard definition of βeff , Nauchi's βeff and Meulekamp's βeff is approximately 10%. The fundamental value β0 is quite larger than the others in several cases. For all the cases, Meulekamp's βeff is always higher than Nauchi's βeff. This is because Nauchi's βeff considers the average neutron multiplicity value per fission which is large in the high energy range (1MeV-10MeV), while the definition of Meulekamp's βeff does not include this parameter. Furthermore, we evaluate the multi-generation effect on βeff values and demonstrate that this effect should be considered to obtain the standard definition values of βeff. (author)
Method for calculating annual energy efficiency improvement of TV sets
Energy Technology Data Exchange (ETDEWEB)
Varman, M. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mahlia, T.M.I. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)]. E-mail: indra@um.edu.my; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)
2006-10-15
The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification.
Method for calculating annual energy efficiency improvement of TV sets
International Nuclear Information System (INIS)
The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification
A new method for calculation of an air quality index
Energy Technology Data Exchange (ETDEWEB)
Ilvessalo, P. [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.
1995-12-31
Air quality measurement programs in Finnish towns have expanded during the last few years. As a result of this it is more and more difficult to make use of all the measured concentration data. Citizens of Finnish towns are nowadays taking more of an interest in the air quality of their surroundings. The need to describe air quality in a simplified form has increased. Air quality indices permit the presentation of air quality data in such a way that prevailing conditions are more easily understandable than when using concentration data as such. Using an air quality index always means that some of the information about concentrations of contaminants in the air will be lost. How much information is possible to extract from a single index number depends on the calculation method. A new method for the calculation of an air quality index has been developed. This index always indicates the overstepping of an air quality guideline level. The calculation of this air quality index is performed using the concentrations of all the contaminants measured. The index gives information both about the prevailing air quality and also the short-term trend. It can also warn about the expected exceeding of guidelines due to one or several contaminants. The new index is especially suitable for the real-time monitoring and notification of air quality values. The behaviour of the index was studied using material from a measurement period in the spring of 1994 in Kaepylae, Helsinki. Material from a pre-operational period in the town of Oulu was also available. (author)
An accurate δf method for neoclassical transport calculation
International Nuclear Information System (INIS)
A δf method, solving drift kinetic equation, for neoclassical transport calculation is presented in detail. It is demonstrated that valid results essentially rely on the correct evaluation of marker density g in weight calculation. A general and accurate weighting scheme is developed without using some assumed g in weight equation for advancing particle weights, unlike the previous schemes. This scheme employs an additional weight function to directly solve g from its kinetic equation using the idea of δf method. Therefore the severe constraint that the real marker distribution must be consistent with the initially assumed g during a simulation is relaxed. An improved like-particle collision scheme is presented. By performing compensation for momentum, energy and particle losses arising from numerical errors, the conservations of all the three quantities are greatly improved during collisions. Ion neoclassical transport due to self-collisions is examined under finite banana case as well as zero banana limit. A solution with zero particle and zero energy flux (in case of no temperature gradient) over whole poloidal section is obtained. With the improvement in both like-particle collision scheme and weighting scheme, the δf simulation shows a significantly upgraded performance for neoclassical transport study. (author)
Simulation of FEL pulse length calculation with THz streaking method.
Gorgisyan, I; Ischebeck, R; Prat, E; Reiche, S; Rivkin, L; Juranić, P
2016-05-01
Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump-probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision. PMID:27140142
An accurate {delta}f method for neoclassical transport calculation
Energy Technology Data Exchange (ETDEWEB)
Wang, W.X.; Nakajima, N.; Murakami, S.; Okamoto, M. [National Inst. for Fusion Science, Toki, Gifu (Japan)
1999-03-01
A {delta}f method, solving drift kinetic equation, for neoclassical transport calculation is presented in detail. It is demonstrated that valid results essentially rely on the correct evaluation of marker density g in weight calculation. A general and accurate weighting scheme is developed without using some assumed g in weight equation for advancing particle weights, unlike the previous schemes. This scheme employs an additional weight function to directly solve g from its kinetic equation using the idea of {delta}f method. Therefore the severe constraint that the real marker distribution must be consistent with the initially assumed g during a simulation is relaxed. An improved like-particle collision scheme is presented. By performing compensation for momentum, energy and particle losses arising from numerical errors, the conservations of all the three quantities are greatly improved during collisions. Ion neoclassical transport due to self-collisions is examined under finite banana case as well as zero banana limit. A solution with zero particle and zero energy flux (in case of no temperature gradient) over whole poloidal section is obtained. With the improvement in both like-particle collision scheme and weighting scheme, the {delta}f simulation shows a significantly upgraded performance for neoclassical transport study. (author)
An improved method for calculation of interface pressure force in PLIC-VOF methods
International Nuclear Information System (INIS)
Conventional methods for the modeling of surface tension force in Piecewise Linear Interface Calculation-Volume of Fluid (PLIC-VOF) methods, such as Continuum Surface Force (CSF), Continuum Surface Stress (CSS) and also Meier's method, convert the surface tension force into a body force. Not only do they include the force in the interfacial cells but also in the neighboring cells. Thus they produce spurious currents. Also the pressure jump, due to the surface tension, is not calculated accurately in these methods. In this paper a more accurate method for the application of interface force in the computational modeling of free surfaces and interfaces which use PLIC-VOF methods is developed. This method is based on the evaluation of the surface tension force only in the interfacial cells and not the neighboring cells. Also the normal and the interface surface area needed for the calculation of the surface tension force is calculated more accurately. The present method is applied to a two-dimensional motionless drop of liquid and a bubble of gas as well as a non-circular two-dimensional drop, which oscillates due to the surface tension force, in an initially stagnant fluid with no gravity force. The results are compared with the results of the cases when CSF, CSS and Meier's methods are used. It is shown that the present method calculates pressure jump at the interface more accurately and produces less spurious currents comparing to CSS an CSF models. (author)
Present HTR physics calculational methods at the Paul Scherrer Institute
International Nuclear Information System (INIS)
In this paper a general description of HTR related calculational methods and data available at the Paul Scherrer Institute (PSI) is given. The cell codes used are MICROX-2, WIMS-D, and TRAMIX. MICROX-2 is an integral transport theory spectrum code which solves the neutron slowing down and thermalization equations on a detailed energy grid for a two region lattice cell. A second level of heterogeneity can be treated, i.e. the inner region may include two different types of grains (particles). WIMS-D contains tabulations of temperature dependent resonance integrals accurately evaluated for homogeneous mixtures of moderator and absorber at many energy points. Equivalence theorems are utilized to obtain few-group effective cross sections in heterogeneous problems. The intermediate resonance absorption shielding (IR) method of resolved resonances is employed. The spherical geometry of the pebble can be converted into an equivalent cylindrical geometry, and the double heterogeneity can be treated using the available cluster option with a method developed by Segev. TRAMIX is a flexible computer (cell) code which reads fine group nuclear data from a library in the Los Alamos National Laboratory (LANL) format MATXS and produces fine group cross sections using the IR methods. Self-shielded multigroup cross sections produced with these cell codes can be used in connection with the one- and two-dimensional discrete-ordinates finite difference transport codes ONEDANT and TWODANT from LANL for full reactor calculations. Additional interface modules which are available include a BN module for leakage calculations and some library management codes plus the PERT-V diffusion perturbation theory code. Most of the nuclear data libraries for the cell codes are based on the JEF-1 (Joint European File) evaluation. They were processed using the NJOY nuclear data processing system from LANL with additional PSI developments. These libraries include the fast, thermal and resonance data tapes
About possibilities using of theoretical calculation methods in radioecology
International Nuclear Information System (INIS)
Full text: Increasing the radiation level into environment is accompanied by accumulation of radioactive compounds into organism and/or their migration into biosphere. Radiotoxins are accumulated into irradiated plants and animals in result of violation of exchanging processes. The are play an important role at the pathogenesis of irradiation. To date, there is well known that even small quantity of the pesticides capable intensified the radiation effect. To understand the mechanism of radiation effect on physiologically active compounds and their complexes, the knowledge of such molecules three-dimensional organization and electron structure is essential. This work is devoted to study the pesticides of carbamate range, i.e. 'sevin' and its derivatives the physiological activity of which has been connected with cholinesterase degradation. Spatial organization and conformational possibilities of the pesticides has been studied using a method of the theoretical conformational analysis on the base of computational program worked out in laboratory of Molecular Biophysics at the Baku State University. Quantum-chemical methods CNDO/2, AM1 and PM3 and complex programs 'LEV' were used in studies of electronic structures of 'sevin' and number of its analogues. Charge distribution on the atoms, optimization of geometrical electrooptic parameters, as well as molecular electrostatic potentials, electron density and nuclear forces were calculated. Visual maps and surface of valence electron density distribution in the given plane and surface of electron-nuclear forces distribution projection were constructed. The geometrical and energetic characteristics, charges on the atoms of investigated pesticides, as well as the maps and relief of the valence electron density distribution on the atoms have been received. According to calculation results, the changing of charge distribution in naphthalene ring is observed. The conclusion was made that the carbonyl group is essential for
METHOD FOR CALCULATION OF STRESSED STATE SUBSTANTIATED BY DYNAMIC MICROTWIN
Directory of Open Access Journals (Sweden)
V. V. Vlashevich
2015-01-01
Full Text Available Method for calculation of the stressed state in a dynamic twin has been developed on the basis of a non-thin non-coherent micro-twin model with continuous distribution of twinning dislocations at twin boundaries. In this case there is no additional generation with the help of twinning dislocation source. The model takes into account that the twin has coherent and noncoherent boundary sections. The developed model has made it possible to take into consideration a form of non-coherent sections of twinning boundaries in calculations of stressed and deformed state at dynamic twins. It has been established that localized stresses are migrating together with non-coherent sections of the twin. Normal stresses σxx change their sign in relation to direction of the twin development. Shear stresses σxy are alternating in signs in relation to an axis which is perpendicular to the direction of the twin development and which is passing through a mid-point of non-coherent twin section. Distribution of stresses σyy и σyz has similar configuration. Stresses σzx in the second and fourth quarters of XOY plane are negative and the stresses in the first and third quarters are positive. Distribution of stresses σzz practically does not differ from distribution of stresses σyy according to configuration but numerical values of stress tensor component data are different.The results have been obtained without thin twin model that permits to consider only elastic stage of the twinning process. The executed stress calculations at dynamic twin are important for forecasting at the accumulation stage of damage origination which is caused by twinning destruction and permit to improve forecasting accuracy of technical system resources on the basis of twinning materials such as alloys based on iron, copper, zinc, aluminium, titanium.
Gradient type optimization methods for electronic structure calculations
Zhang, Xin; Wen, Zaiwen; Zhou, Aihui
2013-01-01
The density functional theory (DFT) in electronic structure calculations can be formulated as either a nonlinear eigenvalue or direct minimization problem. The most widely used approach for solving the former is the so-called self-consistent field (SCF) iteration. A common observation is that the convergence of SCF is not clear theoretically while approaches with convergence guarantee for solving the latter are often not competitive to SCF numerically. In this paper, we study gradient type methods for solving the direct minimization problem by constructing new iterations along the gradient on the Stiefel manifold. Global convergence (i.e., convergence to a stationary point from any initial solution) as well as local convergence rate follows from the standard theory for optimization on manifold directly. A major computational advantage is that the computation of linear eigenvalue problems is no longer needed. The main costs of our approaches arise from the assembling of the total energy functional and its grad...
NEW METHOD FOR CALCULATION OF STATISTIC MISTAKE IN MARKETING INVESTIGATIONS
Directory of Open Access Journals (Sweden)
V. A. Koldachiov
2015-01-01
Full Text Available An idea of a new method is that while breaking-down analysis sample in some sub-samples there is a probability that an actual value for general body will be inside the interval between the highest and lowest average meaning of sub-sample is much higher of the probability that the given value will be beyond the limits of the indicated interval. In this case a size of the interval appears to be less than analogous parameter while making calculation with the help of the Stewdent formula.Thus, it is possible to reach high accuracy in results of marketing investigations while preserving analysis sample size or reducing the necessary size of analysis sample while preserving level of statistical mistake.
Hamiltonian lattice field theory: Computer calculations using variational methods
International Nuclear Information System (INIS)
A variational method is developed for systematic numerical computation of physical quantities-bound state energies and scattering amplitudes-in quantum field theory. An infinite-volume, continuum theory is approximated by a theory on a finite spatial lattice, which is amenable to numerical computation. An algorithm is presented for computing approximate energy eigenvalues and eigenstates in the lattice theory and for bounding the resulting errors. It is shown how to select basis states and choose variational parameters in order to minimize errors. The algorithm is based on the Rayleigh-Ritz principle and Kato's generalizations of Temple's formula. The algorithm could be adapted to systems such as atoms and molecules. It is shown how to compute Green's functions from energy eigenvalues and eigenstates in the lattice theory, and relate these to physical (renormalized) coupling constants, bound state energies and Green's functions. Thus one can compute approximate physical quantities in a lattice theory that approximates a quantum field theory with specified physical coupling constants. The author discusses the errors in both approximations. In principle, the errors can be made arbitrarily small by increasing the size of the lattice, decreasing the lattice spacing and computing sufficiently long. Unfortunately, the author does not understand the infinite-volume and continuum limits well enough to quantify errors due to the lattice approximation. Thus the method is currently incomplete. The method is applied to real scalar field theories using a Fock basis of free particle states. All needed quantities can be calculated efficiently with this basis. The generalization to more complicated theories is straightforward. The author describes a computer implementation of the method and present numerical results for simple quantum mechanical systems
Hamiltonian lattice field theory: Computer calculations using variational methods
International Nuclear Information System (INIS)
I develop a variational method for systematic numerical computation of physical quantities -- bound state energies and scattering amplitudes -- in quantum field theory. An infinite-volume, continuum theory is approximated by a theory on a finite spatial lattice, which is amenable to numerical computation. I present an algorithm for computing approximate energy eigenvalues and eigenstates in the lattice theory and for bounding the resulting errors. I also show how to select basis states and choose variational parameters in order to minimize errors. The algorithm is based on the Rayleigh-Ritz principle and Kato's generalizations of Temple's formula. The algorithm could be adapted to systems such as atoms and molecules. I show how to compute Green's functions from energy eigenvalues and eigenstates in the lattice theory, and relate these to physical (renormalized) coupling constants, bound state energies and Green's functions. Thus one can compute approximate physical quantities in a lattice theory that approximates a quantum field theory with specified physical coupling constants. I discuss the errors in both approximations. In principle, the errors can be made arbitrarily small by increasing the size of the lattice, decreasing the lattice spacing and computing sufficiently long. Unfortunately, I do not understand the infinite-volume and continuum limits well enough to quantify errors due to the lattice approximation. Thus the method is currently incomplete. I apply the method to real scalar field theories using a Fock basis of free particle states. All needed quantities can be calculated efficiently with this basis. The generalization to more complicated theories is straightforward. I describe a computer implementation of the method and present numerical results for simple quantum mechanical systems
Improved Numerical Method for Calculation of 4-Body Transition Amplitudes
Harris, A. L.
2013-01-01
In order to study 4-body atomic collisions such as excitation-ionization, transfer with target excitation, and double electron capture, the calculation of a nine-dimensional numerical integral is often required. This calculation can become computationally expensive, especially when calculating fully differential cross sections (FDCS), where the positions and momenta of all the particles are known. We have developed a new technique for calculating FDCS using fewer computing hours, but more mem...
Reactor calculation in coarse mesh by finite element method applied to matrix response method
International Nuclear Information System (INIS)
The finite element method is applied to the solution of the modified formulation of the matrix-response method aiming to do reactor calculations in coarse mesh. Good results are obtained with a short running time. The method is applicable to problems where the heterogeneity is predominant and to problems of evolution in coarse meshes where the burnup is variable in one same coarse mesh, making the cross section vary spatially with the evolution. (E.G.)
CALCULATION OF MILL RIGIDITY BY THREE DIMENSION CONTACT BOUNDARY ELEMENT METHOD
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Vertical rigidity of the space self-adaptive 530 high rigidity mill is calculated by applying the boundary element method (BEM) of three-dimension elastic contact problem,which can update the existed deforming separation calculating theory and corresponding methods of material mechanics,elastic mechanics and finite element method.The method has less hypotheses and stronger synthesis in contact-type calculating model.The advantages of the method are high calculating rate,high calculating accuracy,etc..
Dynamic Calculation Method of Beam System Under Low Velocity Impact
Institute of Scientific and Technical Information of China (English)
LI Wen-pei; WANG De-rong; SONG Chun-ming; WANG Ming-yang
2008-01-01
The beating beams and the supporting beams under low velocity impact may be in four different strain stages of deformation depending on the impact intensity and beam structure strength. Based on the different judging conditions of deformation stages, the corresponding calculation models are proposed, the calculation formulae for the determination of the impact force and the beam's lateral displacement are obtained. Calculation shows that the beam's total deflection is small when the flexibility of the supporting component is high and the effect of diminishing deflection disappears almost when the stiffness of the supporting component is high.
Measurement and Calculation Methods of a Stem Image Information
Institute of Scientific and Technical Information of China (English)
Yang Hua; Meng Xianyu; Liu Yan; Cheng Jun
2006-01-01
The paper shows a study on 2-D stem image information collected by a digital camera.Information on a single stem is obtained through calculations after the application of the direct linear transformation model of close-range photogrammetry and binocular stereo vision technology,so that the calculating problem between stem image information and its 2-D coordinate can be solved.Furthermore,the 2-D processing methodology for measuring tree image information simplifies calculating equations and increases calculating speed.Although computer stereo vision techniques for collecting parameters of a single stem shape are comparative,complicated,and expensive,research indicates the efficiently and feasibility of closerange photogrammetry for stem image information.
Estonian oil shale resources calculated by GIS method
International Nuclear Information System (INIS)
A digital map of Estonian oil shale mining was created for joining the data about technological, environmental, and social limitations in the deposit. For evaluating potential resource of oil shale, based on borehole database, its amount, tonnage and energy were calculated. Thereafter the quantity of economical oil shale for power plants and shale oil resource were calculated. Energy rating is the most important factor for determining oil shale reserves in the case of using it for electricity generation. In the case of oil production, data on oil yield and potential resources in oil shale are the most important figures to determine the value of the deposit. Basing on the models, oil resource has been calculated. Resource data can be used for composing master plans for the deposit considering both power generation and oil production. The data can be also used for composing development plans of mines and for logistics calculations. (author)
Comparison of Methods for Calculating Radiative Heat Transfer
Energy Technology Data Exchange (ETDEWEB)
Schock, Alfred; Abbate, M J
2012-01-19
Various approximations for calculating radioactive heat transfer between parallel surfaces are evaluated. This is done by applying the approximations based on total emissivities to a special case of known spectral emissivities, for which exact heat transfer calculations are possible. Comparison of results indicates that the best approximation is obtained by basing the emissivity of the receiving surface primarily on the temperature of the emitter. A specific model is shown to give excellent agreement over a very wide range of values.
An approximate method for calculating the deformation of rotating nuclei
International Nuclear Information System (INIS)
The author presents as a collective model where the potential surface at spin I=0 is calculated in the Nilsson-Strutinsky model, an analytical expression for the moment of inertia is used which depends on the deformation and the pairing gaps for protons and neutrons, and the energy is minimized with respect to these gaps. Calculations in this model are performed for 16Oyb. (HSI)
A mathematical method to calculate efficiency of BF3 detectors
Institute of Scientific and Technical Information of China (English)
SI Fenni; HU Qingyuan; PENG Taiping
2009-01-01
In order to calculate absolute efficiency of the BF3 detector, MCNP/4C code is applied to calculate rela-tive efficiency of the BF3 detector first, and then absolute efficiency is figured out through mathematical techniques. Finally an energy response curve of the BF3 detector for 1~20 MeV neutrons is derived. It turns out that efficiency of BF3 detector are relatively uniform for 2~16 MeV neutrons.
International Nuclear Information System (INIS)
Computer development has a bearing on the choice of methods and their possible uses. The authors discuss the possible uses of the diffusion and transport theories and their limitations. Most of the problems encountered in regard to criticality involve fissile materials in simple or multiple assemblies. These entail the use of methods of calculation based on different principles. There are approximate methods of calculation, but very often, for economic reasons or with a view to practical application, a high degree of accuracy is required in determining the reactivity of the assemblies in question, and the methods based on the Monte Carlo principle are then the most valid. When these methods are used, accuracy is linked with the calculation time, so that the usefulness of the codes derives from their speed. With a view to carrying out the work in the best conditions, depending on the geometry and the nature of the materials involved, various codes must be used. Four principal codes are described, as are their variants; some typical possibilities and certain fundamental results are presented. Finally the accuracies of the various methods are compared. (author)
Benchmark calculations for hexagonal lattices with different methods
International Nuclear Information System (INIS)
Necessity to increase the safety conditions of exploitation of recently designed core of modern nuclear reactors causes stronger requirements to the precision of neutron-physical analysis. To get more precise characteristics of nuclear reactor cells and assembly one can increase the accuracy of neutron-physical calculation analysis by taking account the spectral effects. This paper deals with the analysis of the ZR-6 series of experiments using some components of the KARATE code system. The goal of our investigations is the comparison of measured and calculated parameters of perturbed hexagonal lattices containing Gd2O3 in Al2O3 matrix or water holes/ The quoted results include: the critical y parameters Hcr, dρ/dh and the absorber rod efficiency: Δρ. The experiments are based on doubling time measurements. The calculations have been compared not only to the measured data but to the Monte Carlo code results, too (Authors)
Methods for calculating SEU rates for bipolar and NMOS circuits
McNulty, P. J.; Abdel-Kader, W. G.; Bisgrove, J. M.
1985-12-01
Computer codes developed at Clarkson for simulating charge generation by proton-induced nuclear reactions in well-defined silicon microstructures can be used to calculate SEU rates for specific devices when the critical charge and the dimensions of all SEU sensitive junctions on the device are known, provided one can estimate the contribution from externally-generated charge which enters the sensitive junction by drift and diffusion. Calculations for two important bipolar devices, the AMD 2901B bit slice and the Fairchild 93L422 RAM, for which the dimensions of the sensitive volumes were estimated from available heavy-ion test data, have been found to be in agreement with experimental data. Circuit data for the Intel 2164A, an alpha sensitive dRAM, was provided by the manufacturer. Calculations based on crude assumptions regarding which nuclear recoils and which alphas trigger upsets in the 2164A were found to agree with experimental data.
Calculation of VPP basing on functional analyzing method
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
VPP can be used to deter mine the maxi mumvelocities of a sailboard at various sailing-routes,byestablishing the forces and moments balance-equa-tions on the sail and board in accordance with theprinciple of the maxi mal drive-force.Selectingroute is the most i mportant issue in upwind-sailing,and VPP calculations could provide the basis for de-ter mining the opti mal routes.VPP calculation of the sailboard perfor mance isa complex and difficult research task,and there arefew projects in this research-field...
Comparison of hardenability calculation methods of the heat-treatable constructional steels
International Nuclear Information System (INIS)
Evaluation has been made of the consistency of calculation of the hardenability curves of the selected heat-treatable alloyed constructional steels with the experimental data. The study has been conducted basing on the analysis of present state of knowledge on hardenability calculation employing the neural network methods. Several calculation examples and comparison of the consistency of calculation methods employed are included. (author)
The correlated-k method and related methods for broadband radiation calculations
International Nuclear Information System (INIS)
The fundamentals of radiation calculations in planetary atmospheres have been known for a long time, but the practical problems of calculating radiation over a broad spectral range both efficiently and accurately remain an area of active research. The Goody et al. paper of 1989 established a milestone in that long effort. Goody et al. highlighted attempts to formulate the problem in terms of a few absorption coefficients that could represent typically tens of thousands of coefficients in a rigorous line-by-line calculation. Here we provide a brief background, point out that the correlated-k method is a special case of a broader spectral mapping concept, and mention some new ideas that have emerged recently.
Comparison between ASHRAE and ISO thermal transmittance calculation methods
DEFF Research Database (Denmark)
Blanusa, Petar; Goss, William P.; Roth, Hartwig;
2007-01-01
The intent of this paper is to describe and compare the two different two-dimensional frame/spacer heat transfer calculation methodologies used in North America (FRAME [EEL. The FRAMEplus Toolkit for Heat Transfer Assessment of Building Components, Version 3.0, Enermodal Engineering, Kichener, On...
Classification of methods for annual energy harvesting calculations of photovoltaic generators
International Nuclear Information System (INIS)
Highlights: • The paper presents a novel classification of methods for annual energy harvesting calculation of grid-connected PV systems. • The methods are classified in direct and indirect methods. • Direct methods directly calculate the energy. Indirect methods calculate the energy from the power. • The classification can help the PV professionals in order to choose the most suitable method for each application. - Abstract: Estimating the energy provided by the generators of grid-connected photovoltaic systems is important in order to analyze their economic viability and supervise their operation. The energy harvesting calculation of a photovoltaic generator is not trivial; there are a lot of methods for this calculation. The aim of this paper is to develop a novel classification of methods for annual energy harvesting calculation of a generator of a grid-connected photovoltaic system. The methods are classified in two groups: (1) those that indirectly calculate the energy, i.e. they first calculate the power and from this, they calculate the energy, and (2) those that directly calculate the energy. Furthermore, the indirect methods are grouped in two categories: those that first calculate the I–V curve of the generator and from this, they calculate the power, and those that directly calculate the power. The study has shown that the existing methods differ in simplicity and accuracy, so that the proposed classification is useful in order to choose the most suitable method for each specific application
Analysis of some splitting and roulette algorithms in shield calculations by the Monte Carlo method
International Nuclear Information System (INIS)
Different schemes of using the splitting and roulette methods in calculation of radiation transport in nuclear facility shields by the Monte Carlo method are considered. Efficiency of the considered schemes is estimated on the example of test calculations
Calculations of NMR chemical shifts with APW-based methods
Laskowski, Robert; Blaha, Peter
2012-01-01
We present a full potential, all electron augmented plane wave (APW) implementation of first-principles calculations of NMR chemical shifts. In order to obtain the induced current we follow a perturbation approach [Pickard and Mauri, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.63.245101 63, 245101 (2001)] and extended the common APW + local orbital (LO) basis by several LOs at higher energies. The calculated all-electron current is represented in traditional APW manner as Fourier series in the interstitial region and with a spherical harmonics representation inside the nonoverlapping atomic spheres. The current is integrated using a “pseudocharge” technique. The implementation is validated by comparison of the computed chemical shifts with some “exact” results for spherical atoms and for a set of solids and molecules with available published data.
Calculation of gamma-ray families by Monte Carlo method
International Nuclear Information System (INIS)
Extensive Monte Carlo calculation on gamma-ray families was carried out under appropriate model parameters which are currently used in high energy cosmic ray phenomenology. Characteristics of gamma-ray families are systematically investigated by the comparison of calculated results with experimental data obtained at mountain altitudes. The main point of discussion is devoted to examine the validity of Feynman scaling in the fragmentation region of the multiple meson production. It is concluded that experimental data cannot be reproduced under the assumption of scaling law when primary cosmic rays are dominated by protons. Other possibilities on primary composition and increase of interaction cross section are also examined. These assumptions are consistent with experimental data only when we introduce intense dominance of heavy primaries in E0>1015 eV region and very strong increase of interaction cross section (say sigma varies as Esub(0)sup(0.06)) simultaneously
Score Calculation in Informatics Contests Using Multiple Criteria Decision Methods
Jurate SKUPIENE
2011-01-01
The Lithuanian Informatics Olympiad is a problem solving contest for high school students. The work of each contestant is evaluated in terms of several criteria, where each criterion is measured according to its own scale (but the same scale for each contestant). Several jury members are involved in the evaluation. This paper analyses the problem how to calculate the aggregated score for whole submission in the above mentioned situation. The chosen methodology for solving this problem is Mult...
Multi CPU clusters and calculations by molecular dynamics method
International Nuclear Information System (INIS)
The technical characteristics of multi CPU (Central Processor Unit) clusters in Institute of Ion-Plasma and Laser Technologies AS RUz and Institute of Mathematics and Information Technologies AS RUz are described. There is detail information about cluster s architecture, installed programs and their productivity for decision of molecular dynamics tasks. Molecular dynamics program packages GROMACS, OPENMX and AutoDock-4.2.3 are described. The results of calculations using these program packages are presented. (author)
Hargreaves and other reduced-set methods for calculating evapotranspiration
Shahidian, Shakib; Serralheiro, Ricardo; Serrano, João; Teixeira, José; Haie, Naim; Santos, Francisco
2012-01-01
Globally, irrigation is the main user of fresh water, and with the growing scarcity of this essential natural resource, it is becoming increasingly important to maximize efficiency of water usage. This implies proper management of irrigation and control of application depths in order to apply water effectively according to crop needs. Daily calculation of the Reference Potential Evapotranspiration (ETo) is an important tool in determining the water needs of different crops. The United Nations...
Experiences with leak rate calculations methods for LBB application
Energy Technology Data Exchange (ETDEWEB)
Grebner, H.; Kastner, W.; Hoefler, A.; Maussner, G. [and others
1997-04-01
In this paper, three leak rate computer programs for the application of leak before break analysis are described and compared. The programs are compared to each other and to results of an HDR Reactor experiment and two real crack cases. The programs analyzed are PIPELEAK, FLORA, and PICEP. Generally, the different leak rate models are in agreement. To obtain reasonable agreement between measured and calculated leak rates, it was necessary to also use data from detailed crack investigations.
Cost Accounting Methods and Calculation Agricultural Products` Cost
Saule B. Spatayeva
2015-01-01
In the condition of the current market the effective manage of expenses and calculation accountancy of cost production in agriculture must be aimed to control for resources usage at any level of technology process and getting the accountancy database needed for gaining the management targets.The improving the technologies and set up aspects of business entity activity, taken place for the last decades, which caused a significant influence on condition and structure expenses but could not prov...
7 CFR 51.308 - Methods of sampling and calculation of percentages.
2010-01-01
... 7 Agriculture 2 2010-01-01 2010-01-01 false Methods of sampling and calculation of percentages. 51..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Methods of Sampling and Calculation of Percentages § 51.308 Methods of sampling and calculation of percentages. (a) When the...
Recently developed methods in neutral-particle transport calculations: overview
International Nuclear Information System (INIS)
It has become increasingly apparent that successful, general methods for the solution of the neutral particle transport equation involve a close connection between the spatial-discretization method used and the source-acceleration method chosen. The first form of the transport equation, angular discretization which is discrete ordinates is considered as well as spatial discretization based upon a mesh arrangement. Characteristic methods are considered briefly in the context of future, desirable developments. The ideal spatial-discretization method is described as having the following attributes: (1) positive-positive boundary data yields a positive angular flux within the mesh including its boundaries; (2) satisfies the particle balance equation over the mesh, that is, the method is conservative; (3) possesses the diffusion limit independent of spatial mesh size, that is, for a linearly isotropic flux assumption, the transport differencing reduces to a suitable diffusion equation differencing; (4) the method is unconditionally acceleratable, i.e., for each mesh size, the method is unconditionally convergent with a source iteration acceleration. It is doubtful that a single method possesses all these attributes for a general problem. Some commonly used methods are outlined and their computational performance and usefulness are compared; recommendations for future development are detailed, which include practical computational considerations
Single-Sweep Methods for Free Energy Calculations
Maragliano, Luca; Vanden-Eijnden, Eric
2007-01-01
A simple, efficient, and accurate method is proposed to map multi-dimensional free energy landscapes. The method combines the temperature-accelerated molecular dynamics (TAMD) proposed in [Maragliano & Vanden-Eijnden, Chem. Phys. Lett. 426, 168 (2006)] with a variational reconstruction method using radial-basis functions for the representation of the free energy. TAMD is used to rapidly sweep through the important regions of the free energy landscape and compute the gradient of the free energ...
Methods of parameters calculation for wastes hightemperature plasma processing
Kolesnyk, Vasyl; Orlyk, Volodymyr
2015-01-01
The article presents the methodology of plasma parameters calculation for different ratios of its constituents and taking into account that plasma jet is both a source of thermal energy and a part of initial reaction mixture for various physical and chemical transformations, in particular, those associated with processing of different solid wastes. As the methodology application example carbon conversion by steam-and-air plasma jet is investigated. У роботі запропоновано методику розрах...
Cost Accounting Methods and Calculation Agricultural Products` Cost
Directory of Open Access Journals (Sweden)
Saule B. Spatayeva
2015-04-01
Full Text Available In the condition of the current market the effective manage of expenses and calculation accountancy of cost production in agriculture must be aimed to control for resources usage at any level of technology process and getting the accountancy database needed for gaining the management targets.The improving the technologies and set up aspects of business entity activity, taken place for the last decades, which caused a significant influence on condition and structure expenses but could not provide the increase of economic effectiveness in agriculture.
Projection methods for the calculation of incompressible or dilatable flows
International Nuclear Information System (INIS)
This thesis treats of time resolution methods for the Navier-Stokes equations. Based on the well-known projection method of Chorin and Temam, an original pressure correction method, named 'projection-penalty' is developed. Its specificity concerns the addition of a penalty term in the prediction step, which constrains the predicted velocity to fit with the mass balance. The precision improvements added by this method are demonstrated by some analysis results and by some numerical experiments of incompressible or dilatable flows. Finally, the potentialities offered by the use of the joint finite elements method in this type of fractionary step scheme is studied. Two applications are presented, one for local refinement purpose, the other for the resolution of a multi-physics problem. (J.S.)
A method for the calculation of annual limits on intake
International Nuclear Information System (INIS)
The German Radiation Protection Ordinance issued in 1989 - as well as ICRP Publication 30 - included tables of annual limits on intake (ALIs). These are secondary limits derived to indicate those intake values which are not allowed to be exceeded within a year to meet the primary annual dose limits. The latest ICRP Publications dealing with doses for workers give no ALIs any more and also the IAEA Basic Safety Standards and the Council Directive of the European Commission do not list such values. And also the new Radiation Protection Ordinance as well as the federal gazette with dose coefficients do not include such values any more. However, it may be that they will be included as guiding levels in the calculation principles for the assessment of internal doses. This paper will give reasons why there are no ALIs given any more, it will show how ALIs could be calculated, it will show the influence of additional dose restrictions for female workers of child-bearing age, and it will discuss if radiation protection for the unborn child would be fulfilled if the dose limits of the radiation protection ordinance are met. (orig.)
Godunov Method for Calculating Multicomponent Heterogeneous Medium Flows
Surov, V. S.
2014-03-01
The modified Godunov method intended for integrating the nondivergent systems that describe a multivelocity heterogeneous mixture flow is presented. The linearized Riemann solver has been used in solving the Riemann problems.
A nonlinear analytic function expansion nodal method for transient calculations
Energy Technology Data Exchange (ETDEWEB)
Joo, Han Gyn; Park, Sang Yoon; Cho, Byung Oh; Zee, Sung Quun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1998-12-31
The nonlinear analytic function expansion nodal (AFEN) method is applied to the solution of the time-dependent neutron diffusion equation. Since the AFEN method requires both the particular solution and the homogeneous solution to the transient fixed source problem, the derivation of the solution method is focused on finding the particular solution efficiently. To avoid complicated particular solutions, the source distribution is approximated by quadratic polynomials and the transient source is constructed such that the error due to the quadratic approximation is minimized, In addition, this paper presents a new two-node solution scheme that is derived by imposing the constraint of current continuity at the interface corner points. The method is verified through a series of application to the NEACRP PWR rod ejection benchmark problems. 6 refs., 2 figs., 1 tab. (Author)
A Green's function nodal expansion method for LWR diffusion calculation
International Nuclear Information System (INIS)
A Green's Function Nodal Expansion Method (GNEM) has been developed for the efficient numerical solution of the LWR multi-dimensional neutron diffusion equation. It is an improved version of Nodal Expansion Method (NEM) and Nodal Green's Function Method (NGFM). The code interior fluxes are approximated by a high order polynomial expansion as in NEM. The nodal surface fluxes are coupled with the net currents by using the Green's function method to improve the accuracy. A computer code GNEM has been developed and tested. The numerical results demonstrate that GNEM has the same accuracy as NGFM, while it is twice as fast as NGFM. Especially, the numerical results of TMI-1 core depletion cycles 1 and 6 demonstrate that GNEM is about two times faster than ADMARC and possesses better accuracy
Hourly Calculation Method of Air Source Heat Pump Behavior
Ludovico Danza; Lorenzo Belussi; Italo Meroni; Michele Mililli; Francesco Salamone
2016-01-01
The paper describes an hourly simplified model for the evaluation of the energy performance of heat pumps in cooling mode maintaining a high accuracy and low computational cost. This approach differs from the methods used for the assessment of the overall energy consumption of the building, normally placed in the so-called white or black box models, where the transient conduction equation is deterministically and stochastically solved, respectively. The present method wants to be the expressi...
International Nuclear Information System (INIS)
Uranyl minerals form by oxidation and alteration of uraninite, UO2+x, and the UO2 in used nuclear fuels. The thermodynamic database for these phases is extremely limited. However, the Gibbs free energies and enthalpies for uranyl phases may be estimated based on a method that sums polyhedral contributions. The molar contributions of the structural components to Δf Gm0 and Δf Hm0 are derived by multiple regression using the thermodynamic data of phases for which the crystal structures are known. In comparison with experimentally determined values, the average residuals associated with the predicted Δf Gm0 and Δf Hm0 for the uranyl phases used in the model are 0.08 and 0.10%, respectively. There is also good agreement between the predicted mineral stability relations and field occurrences, thus providing confidence in this method for the estimation of Δf Gm0 and Δf Hm0 of the U(VI) phases. This approach provides a means of generating estimated thermodynamic data for performance assessment calcination and a basic for making bounding calcination of phase stabilities and solubilities. (author)
A New Pseudospectral Method for Calculations of Hydrogen Atom in Arbitrary External Fields
Institute of Scientific and Technical Information of China (English)
QIAO Hao-Xue; LI Bai-Wen1
2002-01-01
A new pseudospectral method was introduced to calculate wavefunctions and energy levels of hydrogen atom in arbitrary potential. Some results of hydrogen atom in uniform magnetic fields were presented, high accuracy of results was obtained with simple calculations, and our calculations show very fast convergence. It suggests a new methodfor calculations of hydrogen atom in external fields.
[Calculating method for crop water requirement based on air temperature].
Tao, Guo-Tong; Wang, Jing-Lei; Nan, Ji-Qin; Gao, Yang; Chen, Zhi-Fang; Song, Ni
2014-07-01
The importance of accurately estimating crop water requirement for irrigation forecast and agricultural water management has been widely recognized. Although it has been broadly adopted to determine crop evapotranspiration (ETc) via meteorological data and crop coefficient, most of the data in whether forecast are qualitative rather than quantitative except air temperature. Therefore, in this study, how to estimate ETc precisely only using air temperature data in forecast was explored, the accuracy of estimation based on different time scales was also investigated, which was believed to be beneficial to local irrigation forecast as well as optimal management of water and soil resources. Three parameters of Hargreaves equation and two parameters of McClound equation were corrected by using meteorological data of Xinxiang from 1970 to 2010, and Hargreaves equation was selected to calculate reference evapotranspiration (ET0) during the growth period of winter wheat. A model of calculating crop water requirement was developed to predict ETc at time scales of 1, 3, and 7 d intervals through combining Hargreaves equation and crop coefficient model based on air temperature. Results showed that the correlation coefficients between measured and predicted values of ETc reached 0.883 (1 d), 0.933 (3 d), and 0.959 (7 d), respectively. The consistency indexes were 0.94, 0.95 and 0.97, respectively, which showed that forecast error decreased with the increasing time scales. Forecasted accuracy with an error less than 1 mm x d(-1) was more than 80%, and that less than 2 mm x d(-1) was greater than 90%. This study provided sound basis for irrigation forecast and agricultural management in irrigated areas since the forecasted accuracy at each time scale was relatively high. PMID:25345053
International Nuclear Information System (INIS)
The paper aims to present the main physical principles for selection of design characteristics of the fast reactor control rods (CR) system. The brief analysis of problems of CR physical calculations is given. Four components are described for the correction to the control rod worth calculated by the routine method based on the few - group three - dimensional diffusion code (TRIGEX) in hexagonal geometry. Principle considerations are given for the choice of the original task discretization methods implemented in this code to minimize the total error. Brief information is given about methods and codes used for the evaluation of error components of control rod worths calculated in a standard way. The results of experimental and calculational investigations of control rod physical characteristics are presented. These results were obtained at BFS critical assemblies simulating LMFBR cores. The investigations have been carried out for different types of core configurations. The experimental and calculated values are given on the distortion of power distribution due to the control rod insertion in the core. (author). 51 refs, 9 figs, 5 tabs
International Nuclear Information System (INIS)
Many methods are used to calculate the positron lifetime, these methods could be divided into two main types. The first method is atomic superposition approximation method and the second one is the so called energy band calculation method. They are also known as the non-self-consistent field method and self-consistent field method respectively. In this paper, we first introduce the two basic methods and then, we take Si as an example and give our calculation results, these results coincide with our latest experimental results, finally, we discuss the advantages and disadvantages of the two methods
Transport survey calculations using the spectral collocation method
International Nuclear Information System (INIS)
A novel transport survey code has been developed and is being used to study the sensitivity of stellarator reactor performance to various transport assumptions. Instead of following one of the usual approaches, the steady-state transport equation are solved in integral form using the spectral collocation method. This approach effectively combine the computational efficiency of global models with the general nature of 1-D solutions. A compact torsatron reactor test case was used to study the convergence properties and flexibility of the new method. The heat transport model combined Shaing's model for ripple-induced neoclassical transport, the Chang-Hinton model for axisymmetric neoclassical transport, and neoalcator scaling for anomalous electron heat flux. Alpha particle heating, radiation losses, classical electron-ion heat flow, and external heating were included. For the test problem, the method exhibited some remarkable convergence properties. As the number of basis functions was increased, the maximum, pointwise error in the integrated power balance decayed exponentially until the numerical noise level as reached. Better than 10% accuracy in the globally-averaged quantities was achieved with only 5 basis functions; better than 1% accuracy was achieved with 10 basis functions. The numerical method was also found to be very general. Extreme temperature gradients at the plasma edge which sometimes arise from the neoclassical models and are difficult to resolve with finite-difference methods were easily resolved. 8 refs., 6 figs
Comparison of methods for numerical calculation of continuum damping
Bowden, George; Hole, Matthew; Gorelenkov, Nikolai; Dennis, Graham
2014-01-01
Continuum resonance damping is an important factor in determining the stability of certain global modes in fusion plasmas. A number of analytic and numerical approaches have been developed to compute this damping, particularly in the case of the toroidicity-induced shear Alfv\\'en eigenmode. This paper compares results obtained using an analytical perturbative approach with those found using resistive and complex contour numerical approaches. It is found that the perturbative method does not provide accurate agreement with reliable numerical methods for the range of parameters examined. This discrepancy exists even in the limit where damping approaches zero. When the perturbative technique is implemented using a standard finite element method, the damping estimate fails to converge with radial grid resolution. The finite elements used cannot accurately represent the eigenmode in the region of the continuum resonance, regardless of the number of radial grid points used.
Analytical method of spectra calculations in the Bargmann representation
International Nuclear Information System (INIS)
We formulate a universal method for solving an arbitrary quantum system which, in the Bargmann representation, is described by a system of linear equations with one independent variable, such as one- and multi-photon Rabi models, or N level systems interacting with a single mode of the electromagnetic field and their various generalizations. We explain three types of conditions that determine the spectrum and show their usage for two deformations of the Rabi model. We prove that the spectra of both models are just zeros of transcendental functions, which in one case are given explicitly in terms of confluent Heun functions. - Highlights: • Analytical method of spectrum determination in Bargmann representation is proposed. • Three types of conditions determining spectrum are identified. • Method to two generalizations of the Rabi system is applied
Three-dimensional calculations using the quiet implicit PIC method
International Nuclear Information System (INIS)
Solution of the time-implicit moment equations for electron and ion species, combined with Maxwell's equations, is the kernel of the moment-implicit particle method and of the quiet implicit PIC method, a generalized δf method for electromagnetic plasma simulation. Previous implementations have used a variety of direct and iterative approaches for obtaining solutions to large sparse linear systems. These methods suffer from both excessive computational cost, sometimes negating the advantage of implicit time differencing; and from lack of convergence in some regimes of interest, rendering the method inapplicable. We describe a new formulation of the coupled problem, leading to a symmetric, positive definite system. We also show that this symmetric problem may be efficiently and reliably solved by a conjugate gradient method. A three-dimensional algorithm has been constructed, using a pseudospectral Fourier treatment of the poloidal and toroidal directions, and a finite difference treatment of the radial direction. The radially-dependent, poloidal and toroidal averaged operator is used as a preconditioner. Convergence is rapid, with a typical iteration count of 10 for 10-5 convergence. New results of the two-fluid form of this code to an internal m = 1 internal kink mode will be presented. The algorithm's ability to reproduce kinetic properties of plasmas is being tested with a one-dimensional code, which has recently been modified to permit periodic boundary conditions. When a nonuniform temperature distribution is imposed as an initial condition, the gradients axe reduced by long mean-free-path particles that stream parallel to the magnetic field. Tests of collisionless wave damping have also been conducted for the ion-cyclotron range of frequencies, and results axe compared with analytic predictions
Ab initio calculations of mechanical properties: Methods and applications
Czech Academy of Sciences Publication Activity Database
Pokluda, J.; Černý, Miroslav; Šob, Mojmír; Umeno, Y.
2015-01-01
Roč. 73, AUG (2015), s. 127-158. ISSN 0079-6425 R&D Projects: GA ČR(CZ) GAP108/12/0311 Institutional support: RVO:68081723 Keywords : Ab initio methods * Elastic moduli * Intrinsic hardness * Stability analysis * Theoretical strength * Intrinsic brittleness/ductility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 27.417, year: 2014
Hourly Calculation Method of Air Source Heat Pump Behavior
Directory of Open Access Journals (Sweden)
Ludovico Danza
2016-04-01
Full Text Available The paper describes an hourly simplified model for the evaluation of the energy performance of heat pumps in cooling mode maintaining a high accuracy and low computational cost. This approach differs from the methods used for the assessment of the overall energy consumption of the building, normally placed in the so-called white or black box models, where the transient conduction equation is deterministically and stochastically solved, respectively. The present method wants to be the expression of the grey box model, taking place between the previous approaches. The building envelope is defined using a building thermal model realized with a 3 Resistance 1 Capacitance (3R1C thermal network based on the solution of the lumped capacitance method. The simplified model evaluates the energy efficiency ratio (EER of a heat pump through the determination of the hourly second law efficiency of a reversed Carnot cycle. The results of the simplified method were finally compared with those provided by EnergyPlus, a dynamic building energy simulation program, and those collected from an outdoor test cell in real working conditions. The results are presented in temperatures and energy consumptions profiles and are validated using the Bland-Altman test.
International Nuclear Information System (INIS)
A new method for the calculation of sensitivity coefficients is developed. The new method is a combination of two methodologies used for calculating theses coefficients, which are the differential and the generalized perturbation theory methods. The method utilizes as integral parameter the average flux in an arbitrary region of the system. Thus, the sensitivity coefficient contains only the component corresponding to the neutron flux. To obtain the new sensitivity coefficient, the derivatives of the integral parameter, Φ, with respect to σ are calculated using the perturbation method and the functional derivatives of this generic integral parameter with respect to σ and Φ are calculated using the differential method. (author)
A Direct Iteration Method using Resonance Integral Table for the Self-Shielding Calculations
International Nuclear Information System (INIS)
In this paper, a direct iteration method using the resonance integral table is introduced for the self-shielding calculations. The basic purpose of this paper is to show the possibility that the HELIOS subgroup method can be replaced with this method. This method doesn't use the subgroup data but only the resonance integral tables given in library. The basic idea of this method is to use the Bondarenko's iteration in order to obtain the self-shielded effective cross sections with the background cross sections which are calculated by the heterogeneous transport calculation. This method is implemented in the KARMA lattice calculation code and tested
A Direct Iteration Method using Resonance Integral Table for the Self-Shielding Calculations
Energy Technology Data Exchange (ETDEWEB)
Hong, Ser Gi; Kim, Kang Seog; Song, Jae Seung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2009-10-15
In this paper, a direct iteration method using the resonance integral table is introduced for the self-shielding calculations. The basic purpose of this paper is to show the possibility that the HELIOS subgroup method can be replaced with this method. This method doesn't use the subgroup data but only the resonance integral tables given in library. The basic idea of this method is to use the Bondarenko's iteration in order to obtain the self-shielded effective cross sections with the background cross sections which are calculated by the heterogeneous transport calculation. This method is implemented in the KARMA lattice calculation code and tested.
Comparison of methods for numerical calculation of continuum damping
Bowden, George; Könies, Axel; Hole, Matthew; Gorelenkov, Nikolai; Dennis, Graham
2014-01-01
Continuum resonance damping is an important factor in determining the stability of certain global modes in fusion plasmas. A number of analytic and numerical approaches have been developed to compute this damping, particularly in the case of the toroidicity-induced shear Alfv\\'en eigenmode. This paper compares results obtained using an analytical perturbative approach with those found using resistive and complex contour numerical approaches. It is found that the perturbative method does not p...
Relief valve discharge piping calculational methods and results
International Nuclear Information System (INIS)
The analysis of a safety relief valve and its connecting discharge pipe is an important parameter in the design of a light water reactor plant. This paper addresses the computer modelling techniques and methods used for this analysis and presents guidelines, cautions and improvements which should be used for design. Specific discussions include considerations for loop seal design, heat transfer effects, pipe submergence, reflood effects and vacuum breaker design. (orig.)
Free-energy calculation methods for collective phenomena in membranes
Smirnova, Yuliya G.; Fuhrmans, Marc; Barragan Vidal, Israel A.; Müller, Marcus
2015-09-01
Collective phenomena in membranes are those which involve the co-operative reorganization of many molecules. Examples of these are membrane fusion, pore formation, bending, adhesion or fission. The time and length scales, on which these processes occur, pose a challenge for atomistic simulations. Therefore, in order to solve the length scale problem it is popular to introduce a coarse-grained representation. To facilitate sampling of the relevant states additional computational techniques, which encourage the system to explore the free-energy landscape far from equilibrium and visit transition states, are needed. These computational techniques provide insights about the free-energy changes involved in collective transformations of membranes, yielding information about the rate limiting states, the transformation mechanism and the influence of architectural, compositional and interaction parameters. A common approach is to identify an order parameter (or reaction coordinate), which characterizes the pathway of membrane reorganization. However, no general strategy exists to define such an order parameter that can properly describe cooperative reorganizations in membranes. Recently developed methods can overcome this problem of the order-parameter choice and allow us to study collective phenomena in membranes. We will discuss such methods as thermodynamic integration, umbrella sampling, and the string method and results provided by their applications to particle-based simulations, particularly focusing on membrane fusion and pore formation.
Free-energy calculation methods for collective phenomena in membranes
International Nuclear Information System (INIS)
Collective phenomena in membranes are those which involve the co-operative reorganization of many molecules. Examples of these are membrane fusion, pore formation, bending, adhesion or fission. The time and length scales, on which these processes occur, pose a challenge for atomistic simulations. Therefore, in order to solve the length scale problem it is popular to introduce a coarse-grained representation. To facilitate sampling of the relevant states additional computational techniques, which encourage the system to explore the free-energy landscape far from equilibrium and visit transition states, are needed. These computational techniques provide insights about the free-energy changes involved in collective transformations of membranes, yielding information about the rate limiting states, the transformation mechanism and the influence of architectural, compositional and interaction parameters. A common approach is to identify an order parameter (or reaction coordinate), which characterizes the pathway of membrane reorganization. However, no general strategy exists to define such an order parameter that can properly describe cooperative reorganizations in membranes. Recently developed methods can overcome this problem of the order-parameter choice and allow us to study collective phenomena in membranes. We will discuss such methods as thermodynamic integration, umbrella sampling, and the string method and results provided by their applications to particle-based simulations, particularly focusing on membrane fusion and pore formation. (topical review)
Rate Constant Calculation for Thermal Reactions Methods and Applications
DaCosta, Herbert
2011-01-01
Providing an overview of the latest computational approaches to estimate rate constants for thermal reactions, this book addresses the theories behind various first-principle and approximation methods that have emerged in the last twenty years with validation examples. It presents in-depth applications of those theories to a wide range of basic and applied research areas. When doing modeling and simulation of chemical reactions (as in many other cases), one often has to compromise between higher-accuracy/higher-precision approaches (which are usually time-consuming) and approximate/lower-preci
Visual Method for Spectral Energy Distribution Calculation of Blazars
Indian Academy of Sciences (India)
Y. Huang; J. H. Fan
2014-09-01
In this work, we propose to use `The Geometer’s Sketchpad’ to the fitting of a spectral energy distribution of blazar based on three effective spectral indices, RO, OX, and RX and the flux density in the radio band. It can make us to see the fitting in detail with both the peak frequency and peak luminosity given immediately. We used our method to those sources whose peak frequency and peak luminosity are given and found that our results are consistent with those given in the work of Sambruna et al. (1996).
New nuclear medicine method of calculating left ventricular stroke volume
Energy Technology Data Exchange (ETDEWEB)
Gieschke, R.; Luig, H.; Reuter, R.; Figulla, H.R.
1983-12-01
A new non-invasive nuclear medicine procedure for determining the left ventricular stroke volume is described. The procedure exhibits the following features: 1. individual calibration of scintigraphic counts in activity by first-pass evaluation; 2. no need for a delta-shaped bolus injection; and 3. determination of different stroke volumes, e.g. during different grades of exercise, by only one injection and by only one blood sample. 36 results obtained at rest and during exercise are compared with corresponding results of the thermodilution method (r = 0.86).
Study on increasing calculation precision and convergence speed of streamline strip element method
Institute of Scientific and Technical Information of China (English)
彭艳; 刘宏民
2004-01-01
The calculation precision and convergence speed of streamline strip element method are increased by using the method whose initial value of the exit lateral displacement is determined with strip element variation method, and the accurate tension lateral distribution model is adopted based on the original third power spline function streamline strip element method. The basic theory of the strip element method is developed. The calculated results by the improved streamline strip element method and the original streamline strip element method are compared with the measured results, showing that the calculated results of the improved method are in good agreement with the measured results.
Comparison of hardenability calculation methods of the heat-treatable constructional steels
Energy Technology Data Exchange (ETDEWEB)
Dobrzanski, L.A.; Sitek, W. [Division of Tool Materials and Computer Techniques in Metal Science, Silesian Technical University, Gliwice (Poland)
1995-12-31
Evaluation has been made of the consistency of calculation of the hardenability curves of the selected heat-treatable alloyed constructional steels with the experimental data. The study has been conducted basing on the analysis of present state of knowledge on hardenability calculation employing the neural network methods. Several calculation examples and comparison of the consistency of calculation methods employed are included. (author). 35 refs, 2 figs, 3 tabs.
Finite element method in density functional theory electronic structure calculations
Czech Academy of Sciences Publication Activity Database
Vackář, Jiří; Čertík, Ondřej; Cimrman, R.; Novák, M.; Šipr, Ondřej; Plešek, Jiří
Berlin : Springer, 2012 - (Hoggan, P.; Brändas, E.; Maruani, J.; Piecuch, P.; Delgado- Barrio , G.), s. 199-217 ISBN 978-94-007-2075-6. - (Progress in Theoretical Chemistry and Physics. vol. 12) R&D Projects: GA ČR GA101/09/1630; GA ČR(CZ) GAP108/11/0853; GA MŠk(CZ) LC06040 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521; CEZ:AV0Z20760514 Keywords : finite-element method * pseudopotentials * density functional theory Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.springerlink.com/content/p7k3j7047720270r/
A numerical method for calculating resonant-state wave functions
International Nuclear Information System (INIS)
An initial-value method of numerical solving of Sturm-Liouville problems is applied to find the solution to the Schroedinger equation which corresponds to a resonance situation. The depth of the nuclear potential is regarded as an eigenvalue, which is obtained by iteration. Having established the nuclear potential, the resonant wavefunction is generated by integrating numerically the Schroedinger differential equation inwards from larger radii using the initial conditions of G(r), where G is the irregular Coulomb function. Because the solution is exactly on resonance, nosearching for the phase shift is required. Consequently, the suggested procedure may be employed even if the resonance widths are extremely narrow (e.g., 10-16 MeV)
Study on the Processing Method for Resonance Self-shielding Calculations
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
We investigate a new approach for resonance self-shielding calculations, based on a straightforward subgroup method, used in association with characteristics method. Subgroup method is actually the subdivision of cross section range for resonance energy range.
A high-precision calculation method for interface normal and curvature on an unstructured grid
Ito, Kei; Kunugi, Tomoaki; Ohno, Shuji; Kamide, Hideki; Ohshima, Hiroyuki
2014-09-01
In the volume-of-fluid algorithm, the calculations of the interface normal and curvature are crucially important for accurately simulating interfacial flows. However, few methods have been proposed for the high-precision interface calculation on an unstructured grid. In this paper, the authors develop a height function method that works appropriately on an unstructured grid. In the process, the definition of the height function is discussed, and the high-precision calculation method of the interface normal is developed to meet the necessary condition for a second-order method. This new method has highly reduced computational cost compared with a conventional high-precision method because the interface normal calculation is completed by solving relatively simple algebraic equations. The curvature calculation method is also discussed and the approximated quadric curve of an interface is employed to calculate the curvature. Following a basic verification, the developed height function method is shown to successfully provide superior calculation accuracy and highly reduced computational cost compared with conventional calculation methods in terms of the interface normal and curvature. In addition, the height function method succeeds in calculating accurately the slotted-disk revolution problem and the oscillating drop on unstructured grids. Therefore, the developed height function method is confirmed to be an efficient technique for the high-precision numerical simulation of interfacial flows on an unstructured grid.
Theories and calculation methods for regional objective ET
Institute of Scientific and Technical Information of China (English)
QIN DaYong; LO JinYan; LIU JiaHong; WANG MingNa
2009-01-01
The regional objective ET (Evapotranspiration) is a new concept in water resources research, which refers to the total amount of water that could be exhausted from a region in the form of vapor per year. The objective-ET based water resources management allocates water to different regions in terms of ET. It controls the water exhausted from a region to meet the objective ET. The regional objective ET must be adapted to fit the region's local available water resources. By improving the water utilization effi-ciency and reducing the unrecoverable water in the social water circle, it is saved so that water related production is maintained or even increased under the same water consumption conditions. Regional water balance is realized by rationally deploying the available water among different industries, adjusting industrial structures, and adopting new water-saving technologies, therefore to meeting the requirements for groundwater conservation, agricultural income stability, and avoiding environmental damages. Furthermore, water competition among various departments and industries (including envi-ronmental and ecological water use) may be avoided. This paper proposes an innovative definition of objective ET, and its principles, sub-index systems. Besides, a computational method for regional ob-jective ET is developed by combining the distributed hydrological model and the soil moisture model.
Comparison of organ dosimetry methods and effective dose calculation methods for paediatric CT
International Nuclear Information System (INIS)
Computed tomography (CT) is the single biggest ionising radiation risk from anthropogenic exposure. Reducing unnecessary carcinogenic risks from this source requires the determination of organ and tissue absorbed doses to estimate detrimental stochastic effects. In addition, effective dose can be used to assess comparative risk between exposure situations and facilitate dose reduction through optimisation. Children are at the highest risk from radiation induced carcinogenesis and therefore dosimetry for paediatric CT recipients is essential in addressing the ionising radiation health risks of CT scanning. However, there is no well-defined method in the clinical environment for routinely and reliably performing paediatric CT organ dosimetry and there are numerous methods utilised for estimating paediatric CT effective dose. Therefore, in this study, eleven computational methods for organ dosimetry and/or effective dose calculation were investigated and compared with absorbed doses measured using thermoluminescent dosemeters placed in a physical anthropomorphic phantom representing a 10 year old child. Three common clinical paediatric CT protocols including brain, chest and abdomen/pelvis examinations were evaluated. Overall, computed absorbed doses to organs and tissues fully and directly irradiated demonstrated better agreement (within approximately 50 %) with the measured absorbed doses than absorbed doses to distributed organs or to those located on the periphery of the scan volume, which showed up to a 15-fold dose variation. The disparities predominantly arose from differences in the phantoms used. While the ability to estimate CT dose is essential for risk assessment and radiation protection, identifying a simple, practical dosimetry method remains challenging.
Preconditioned Conjugate Gradient methods for low speed flow calculations
Ajmani, Kumud; Ng, Wing-Fai; Liou, Meng-Sing
1993-01-01
An investigation is conducted into the viability of using a generalized Conjugate Gradient-like method as an iterative solver to obtain steady-state solutions of very low-speed fluid flow problems. Low-speed flow at Mach 0.1 over a backward-facing step is chosen as a representative test problem. The unsteady form of the two dimensional, compressible Navier-Stokes equations are integrated in time using discrete time-steps. The Navier-Stokes equations are cast in an implicit, upwind finite-volume, flux split formulation. The new iterative solver is used to solve a linear system of equations at each step of the time-integration. Preconditioning techniques are used with the new solver to enhance the stability and the convergence rate of the solver and are found to be critical to the overall success of the solver. A study of various preconditioners reveals that a preconditioner based on the lower-upper (L-U)-successive symmetric over-relaxation iterative scheme is more efficient than a preconditioner based on incomplete L-U factorizations of the iteration matrix. The performance of the new preconditioned solver is compared with a conventional line Gauss-Seidel relaxation (LGSR) solver. Overall speed-up factors of 28 (in terms of global time-steps required to converge to a steady-state solution) and 20 (in terms of total CPU time on one processor of a CRAY-YMP) are found in favor of the new preconditioned solver, when compared with the LGSR solver.
Directory of Open Access Journals (Sweden)
Odru P.
2006-11-01
Full Text Available Cet article présente une méthode de calcul des structures composites fibres-résine appliquée aux cas des tubes minces. Outre l'établissement des relations contraintes - déformations généralisées des tubes à partir des caractéristiques des matériaux de base et de leur orientation, on pose les relations permettant de calculer leur comportement et leur dimensionnement sous des charges axisymétriques combinées de traction, pression et flexion. Une méthode simplifiée applicable au cas des composites microfissurés est aussi présentée. On montre ensuite, à travers quelques exemples concrets d'applications, les propriétés intéressantes ou inhabituelles que le matériau permet de conférer aux structures. This article presents a method of calculation of composite structures applied to thin-walled tubes. Starting from the characteristics and orientation of the basic materials, the generalized stress-strain equations of the tubes are determined ; then the relationship allowing the calculation of their design and behavior under combined axisymmetrical loads of tension, pressure and bending are established. A simplified method applicable to microcracked composite materials is also described. Several complete examples of applications illustrate the interesting or unusual properties that this material can impart to structures
Lesniak, Joseph; Behrman, Elizabeth; Zandler, Melvin; Kumar, Preethika
2008-03-01
Very few quantum algorithms are currently useable today. When calculating molecular energies, using a quantum algorithm takes advantage of the quantum nature of the algorithm and calculation. A few small molecules have been used to show that this method is possible. This method will be applied to larger molecules and compared to classical computer methods.
DEFF Research Database (Denmark)
Zhang, Wen-juan; Huang, Shou-dao; Chen, Zhe
2013-01-01
An analytic electromagnetic calculation method for doubly fed induction generator (DFIG) in wind turbine system was presented. Based on the operation principles, steady state equivalent circuit and basic equations of DFIG, the modeling for electromagnetic calculation of DFIG was proposed. The...... electromagnetic calculation of DFIG was divided into three steps: the magnetic flux calculation, parameters derivation and performance checks. For each step, the detailed numeric calculation formulas were all derived. Combining the calculation formulas, the whole electromagnetic calculation procedure was...... established, which consisted of three iterative calculation loops, including magnetic saturation coefficient, electromotive force and total output power. All of the electromagnetic and performance data of DIFG can be calculated conveniently by the established calculation procedure, which can be used to...
International Nuclear Information System (INIS)
To calculate total dose effect on semi-conductor devices in satellite for a period of space mission effectively, two approximate calculation models for a comic radiation shielding were proposed. They are a sectoring method and a chord-length distribution method. When an approximate method was applied in this study, complex structure of satellite was described into multiple 1-dimensional slabs, structural materials were converted to reference material(aluminum), and the pre-calculated dose-depth conversion function was introduced to simplify the calculation process. Verification calculation was performed for orbit location and structure geometry of KITSAT-1 and compared with detailed 3-dimensional calculation results and experimental values. The calculation results from approximate method were estimated conservatively with acceptable error. However, results for satellite mission simulation were underestimated in total dose rate compared with experimental values
Perturbation method for calculation of narrow-band impedance and trapped modes
International Nuclear Information System (INIS)
An iterative method for calculation of the narrow-band impedance is described for a system with a small variation in boundary conditions, so that the variation can be considered as a perturbation. The results are compared with numeric calculations. The method is used to relate the origin of the trapped modes with the degeneracy of the spectrum of an unperturbed system. The method also can be applied to transverse impedance calculations. 6 refs., 6 figs., 1 tab
International Nuclear Information System (INIS)
A matrix non-iterative method to calculate the periodical distribution in reactors with thermal regeneration is presented. In case of exothermic reaction, a source term will be included. A computer code was developed to calculate the final temperature distribution in solids and in the outlet temperatures of the gases. The results obtained from ethane oxidation calculation in air, using the Dietrich kinetic data are presented. This method is more advantageous than iterative methods. (E.G.)
Energy Technology Data Exchange (ETDEWEB)
Perfetti, Christopher M [ORNL; Rearden, Bradley T [ORNL
2014-01-01
This work introduces a new approach for calculating sensitivity coefficients for generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The approach presented in this paper, known as the GEAR-MC method, allows for the calculation of generalized sensitivity coefficients for multiple responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here, and proof of principle is demonstrated by using the GEAR-MC method to calculate sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications.
THE PARTICULARITIES OF THE COST CALCULATION METHOD ON COMMANDS IN FURNITURE INDUSTRY
Felicia Sabou
2014-01-01
The paper present the importance of the method on commands in cost calculation and the particularities of the cost calculation method on commands in the furniture industry. This paper presents a hypotetical study on the method on commands, considering the observations made during 2013-2014, on how it is organized and managed accounts management using method on commands.By presenting this hypothetical model about the accounting in management accounting using the method on commands, the pape...
Energy Technology Data Exchange (ETDEWEB)
Perfetti, Christopher M [ORNL; Martin, William R [University of Michigan; Rearden, Bradley T [ORNL; Williams, Mark L [ORNL
2012-01-01
Three methods for calculating continuous-energy eigenvalue sensitivity coefficients were developed and implemented into the SHIFT Monte Carlo code within the Scale code package. The methods were used for several simple test problems and were evaluated in terms of speed, accuracy, efficiency, and memory requirements. A promising new method for calculating eigenvalue sensitivity coefficients, known as the CLUTCH method, was developed and produced accurate sensitivity coefficients with figures of merit that were several orders of magnitude larger than those from existing methods.
A new method for calculating the activity of stable compound from binary phase diagram
Institute of Scientific and Technical Information of China (English)
CHEN Dengfu; DONG Lingyan; BAI Chenguang; LIU Qingcai; WANG Chuanjun
2006-01-01
A new method to calculate the activity of a stable compound in a binary phase diagram was presented and dis cussed. According to the formula for calculating activity from the binary phase diagram, the equilibrium constant can be calculated through the mass action principle after the activities of two pure components were computed respectively. Based on that, the activity of a stable compound can be easily obtained at last. The activity of the stable compound InSb is calculated in the In-Sb binary system by using this method. The result is well consistent with another calculation value.
Shan Yang; Xiangqian Tong
2016-01-01
Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverte...
Comparison of the methods for calculating the interfacial heat transfer coefficient in hot stamping
International Nuclear Information System (INIS)
This paper presents a hot stamping experimentation and three methods for calculating the Interfacial Heat Transfer Coefficient (IHTC) of 22MnB5 boron steel. Comparison of the calculation results shows an average error of 7.5% for the heat balance method, 3.7% for the Beck's nonlinear inverse estimation method (the Beck's method), and 10.3% for the finite-element-analysis-based optimization method (the FEA method). The Beck's method is a robust and accurate method for identifying the IHTC in hot stamping applications. The numerical simulation using the IHTC identified by the Beck's method can predict the temperature field with a high accuracy. - Highlights: • A theoretical formula was derived for direct calculation of IHTC. • The Beck's method is a robust and accurate method for identifying IHTC. • Finite element method can be used to identify an overall equivalent IHTC
JM-ECS: A hybrid method combining the $J$-matrix and ECS methods for scattering calculations
Bidasyuk, Y; Broeckhove, J; Arickx, F; Vasilevsky, V
2010-01-01
The paper proposes a hybrid method for calculating scattering processes that combines the $J$-matrix method with exterior complex scaling as an absorbing boundary condition. It represents the wave function as a finite sum of oscillator eigenstates in the inner region and on grid in the outer region. The method is validated for one and two dimensional model partial wave equation equations. Finally, the method calculates nuclear $p$-shell scattering.
International Nuclear Information System (INIS)
The shell model Monte Carlo (SMMC) method enables calculations in model spaces that are many orders of magnitude larger than those that can be treated by conventional methods, and is particularly suitable for the calculation of level densities in the presence of correlations. We review recent advances and applications of SMMC for the microscopic calculation of level densities. Recent developments include (1) a method to calculate accurately the ground-state energy of an odd-mass nucleus, circumventing a sign problem that originates in the projection on an odd number of particles, and (2) a method to calculate directly level densities, which, unlike state densities, do not include the spin degeneracy of the levels. We calculated the level densities of a family of nickel isotopes 59-64Ni and of a heavy deformed rare-earth nucleus 162Dy and found them to be in close agreement with various experimental data sets. (author)
Alhassid, Y; Liu, S; Mukherjee, A; Nakada, H
2014-01-01
The shell model Monte Carlo (SMMC) method enables calculations in model spaces that are many orders of magnitude larger than those that can be treated by conventional methods, and is particularly suitable for the calculation of level densities in the presence of correlations. We review recent advances and applications of SMMC for the microscopic calculation of level densities. Recent developments include (i) a method to calculate accurately the ground-state energy of an odd-mass nucleus, circumventing a sign problem that originates in the projection on an odd number of particles, and (ii) a method to calculate directly level densities, which, unlike state densities, do not include the spin degeneracy of the levels. We calculated the level densities of a family of nickel isotopes $^{59-64}$Ni and of a heavy deformed rare-earth nucleus $^{162}$Dy and found them to be in close agreement with various experimental data sets.
Efficient method for the calculation of dissipative quantum transport in quantum cascade lasers.
Greck, Peter; Birner, Stefan; Huber, Bernhard; Vogl, Peter
2015-03-01
We present a novel and very efficient method for calculating quantum transport in quantum cascade lasers (QCLs). It follows the nonequilibrium Green's function (NEGF) framework but sidesteps the calculation of lesser self-energies by replacing them by a quasi-equilibrium expression. This method generalizes the phenomenological Büttiker probe model by taking into account individual scattering mechanisms. It is orders of magnitude more efficient than a fully self-consistent NEGF calculation for realistic devices. We apply this method to a new THz QCL design which works up to 250 K - according to our calculations. PMID:25836876
International Nuclear Information System (INIS)
This work introduces a new approach for calculating the sensitivity of generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The GEneralized Adjoint Responses in Monte Carlo (GEAR-MC) method has enabled the calculation of high resolution sensitivity coefficients for multiple, generalized neutronic responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here and proof of principle is demonstrated by calculating sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications. (author)
Ebru Ermis, Elif; Celiktas, Cuneyt
2015-07-01
Calculations of gamma-ray mass attenuation coefficients of various detector materials (crystals) were carried out by means of FLUKA Monte Carlo (MC) method at different gamma-ray energies. NaI, PVT, GSO, GaAs and CdWO4 detector materials were chosen in the calculations. Calculated coefficients were also compared with the National Institute of Standards and Technology (NIST) values. Obtained results through this method were highly in accordance with those of the NIST values. It was concluded from the study that FLUKA MC method can be an alternative way to calculate the gamma-ray mass attenuation coefficients of the detector materials.
Energy Technology Data Exchange (ETDEWEB)
Maita, S.; Nakashima, A.; Ando, J.; Nakatake, K. [Kyushu University, Fukuoka (Japan)
1998-09-04
Based on a simple surface panel method named SQCM, we develop a method to calculate nonlinear cavity on 2-D wing by introducing the four kinds of cavity models, i.e. closed model, semi-closed model, open model and supercavitating model. This method gives pressure distribution, lift and drag of the wing. Then, by combining the QCM program, the concept of the equivalent 2-D wing and the present cavity calculation method, we obtain the characteristics of two cavitating propellers. Comparisons between calculated results and experimental ones confirm the usefulness of our method. 11 refs., 15 figs., 1 tab.
Approximate method for calculating the lifetime of positrons trapped by lattice defects
International Nuclear Information System (INIS)
A method which takes account of core as well as valence electrons is presented for theoretically estimating the life-time of positrons trapped in lattice defects. The method is illustrated by calculations for vacancies and divacancies in aluminum
Hubbell rectangular source integral calculation using a fast Chebyshev wavelets method.
Manai, K; Belkadhi, K
2016-07-01
An integration method based on Chebyshev wavelets is presented and used to calculate the Hubbell rectangular source integral. A study of the convergence and the accuracy of the method was carried out by comparing it to previous studies. PMID:27152913
International Nuclear Information System (INIS)
The band structure of metallic sodium is calculated, using for the first time the self-consistent field variational cellular method. In order to implement the self-consistency in the variational cellular theory, the crystal electronic charge density was calculated within the muffin-tin approximation. The comparison between our results and those derived from other calculations leads to the conclusion that the proposed self-consistent version of the variational cellular method is fast and accurate. (author)
A New Optimization Method for Centrifugal Compressors Based on 1D Calculations and Analyses
Pei-Yuan Li; Chu-Wei Gu; Yin Song
2015-01-01
This paper presents an optimization design method for centrifugal compressors based on one-dimensional calculations and analyses. It consists of two parts: (1) centrifugal compressor geometry optimization based on one-dimensional calculations and (2) matching optimization of the vaned diffuser with an impeller based on the required throat area. A low pressure stage centrifugal compressor in a MW level gas turbine is optimized by this method. One-dimensional calculation results show that D3/D...
A hybrid Monte Carlo and response matrix Monte Carlo method in criticality calculation
International Nuclear Information System (INIS)
Full core calculations are very useful and important in reactor physics analysis, especially in computing the full core power distributions, optimizing the refueling strategies and analyzing the depletion of fuels. To reduce the computing time and accelerate the convergence, a method named Response Matrix Monte Carlo (RMMC) method based on analog Monte Carlo simulation was used to calculate the fixed source neutron transport problems in repeated structures. To make more accurate calculations, we put forward the RMMC method based on non-analog Monte Carlo simulation and investigate the way to use RMMC method in criticality calculations. Then a new hybrid RMMC and MC (RMMC+MC) method is put forward to solve the criticality problems with combined repeated and flexible geometries. This new RMMC+MC method, having the advantages of both MC method and RMMC method, can not only increase the efficiency of calculations, also simulate more complex geometries rather than repeated structures. Several 1-D numerical problems are constructed to test the new RMMC and RMMC+MC method. The results show that RMMC method and RMMC+MC method can efficiently reduce the computing time and variations in the calculations. Finally, the future research directions are mentioned and discussed at the end of this paper to make RMMC method and RMMC+MC method more powerful. (authors)
Method of Time-Delay Calculating and Correcting to Control Spin-Stabilized Satellite Synchronously
Institute of Scientific and Technical Information of China (English)
YangTianshe; LiJisheng; HuangYongxuan
2005-01-01
The key to control Spin-Stabilized Satellites Synchronously is to determine the models for calculating and correcting of time-delay at the different situations. Based on the principle of Synchronous-Control mode, the methods of determining the models of calculating and correcting of time-delay are proposed. The methods have been proved to be effective in real satellite control engineering.
Smit, W.M.A.; Bode, J.H.G.; Straten, A.J. van
1979-01-01
A general method for the calculation of absolute rotational corrections for the dipole moment derivatives is given based on the definition of pure geometrical distortions. The method is generally valid and allows the rotational contributions to be calculated for all modes of any molecule. The relati
THE COST CALCULATION AND ANALYSIS BY MEANS OF THE STANDARD COST METHOD
Directory of Open Access Journals (Sweden)
ADRIANA MONICAŢEGLEDI
2014-05-01
Full Text Available Originally known as the Estimated Cost System, it has evolved, nowadays being called Standard Cost Accounting. Standard cost calculation method is based on scheduled cost, pre-calculated, set before the start of the manufacturing process itself. This method allows the determination of the elements that influence the amount of costs and their deviations from the predetermined costs.
Self-consistent cluster-embedding calculation method and the calculated electronic structure of NiO
International Nuclear Information System (INIS)
The self-consistent cluster-embedding method is discussed theoretically. A definition of the total energy for an embedded cluster has been introduced. The method has two advantages. (i) It can describe both localized and band properties, including their excitations. (ii) It can give a good description of the magnetic properties for both spin-ordered and spin-disordered states. The electronic structure of NiO is studied using a high-quality basis set to calculate the electronic structure of a small embedded cluster and an antiferromagnetic insulating ground state is obtained. The picture has both localized and band properties. A small energy gap separates the unoccupied and occupied nickel 3d orbitals which are well localized. Each 3d orbital is attached to a particular nickel ion. Below the 3d levels are two diffuse oxygen 2p bands, and above the 3d levels are oxygen 3s, nickel 4s, and oxygen 3p bands. Experimental data concerning photoemission and optical absorption can be interpreted naturally. The spin magnetic moment of the nickel ion is calculated correctly. The simulation of the spin-disordered state shows that NiO remains as an insulator in the paramagnetic state. The Neel temperature of NiO is calculated directly to give a reasonable result. The Hubbard U parameter for nickel 3d electrons is estimated. The calculation shows that the excited nickel 3d electrons are also well localized and the overlaps are less than 4.5%. We propose the following: The overlap of the excited 3d electrons is too small to form a metallic band, but the overlap is sufficient for the ''hole'' to migrate through the crystal. In this sense, NiO is a charge-transfer insulator with a gap of about 4 eV (mostly from oxygen to nickel)
DEFF Research Database (Denmark)
Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug
2014-01-01
Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed.......Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed....
DEFF Research Database (Denmark)
Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug
Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed.......Four different numerical methods for calculating the quality factor and resonance wavelength of a nano or micro photonic cavity are compared. Good agreement was found for a wide range of quality factors. Advantages and limitations of the different methods are discussed....
Stiffeners in variational-difference method for calculating shells with complex geometry
Ivanov Vyacheslav Nikolaevich; Kushnarenko Ivan Valer'evich
2014-01-01
We have already considered an introduction of reinforcements in the variational-difference method (VDM) of shells analysis with complex shape. At the moment only ribbed shells of revolution and shallow shells can be calculated with the help of developed analytical and finite-difference methods. Ribbed shells of arbitrary shape can be calculated only using the finite element method (FEM). However there are problems, when using FEM, which are absent in finite- and variational-difference methods...
Efficient calculation method for realistic deep 3D scene hologram using orthographic projection
Igarashi, Shunsuke; Nakamura, Tomoya; Matsushima, Kyoji; Yamaguchi, Masahiro
2016-03-01
We propose a fast calculation method to synthesize a computer-generated hologram (CGH) of realistic deep three-dimensional (3D) scene. In our previous study, we have proposed a calculation method of CGH for reproducing such scene called ray-sampling-plane (RSP) method, in which light-ray information of a scene is converted to wavefront, and the wavefront is numerically propagated based on diffraction theory. In this paper, we introduce orthographic projection to the RSP method for accelerating calculation time. By numerical experiments, we verified the accelerated calculation with the ratio of 28-times compared to the conventional RSP method. The calculated CGH was fabricated by the printing system using laser lithography and demonstrated deep 3D image reconstruction in 52mm×52mm with realistic appearance effect such as gloss and translucent effect.
Energy Technology Data Exchange (ETDEWEB)
NONE
2002-05-01
A working group driven by Electricite de France (EdF), Chauffage Fioul and Gaz de France (GdF) companies has been built with the sustain of several building engineering companies in order to clarify the use of the method of calculation of the global energy cost of buildings. This global cost is an economical decision help criterion among others. This press kit presents, first, the content of the method (input data, calculation of annual expenses, calculation of the global energy cost, display of results and limitations of the method). Then it fully describes the method and its appendixes necessary for its implementation: economical and financial context, general data of the project in progress, environmental data, occupation and comfort level, variants, investment cost of energy systems, investment cost for the structure linked with the energy system, investment cost for other invariant elements of the structure, calculation of consumptions (space heating, hot water, ventilation), maintenance costs (energy systems, structure), operation and exploitation costs, tariffs and consumption costs and taxes, actualized global cost, annualized global cost, comparison between variants. The method is applied to a council building of 23 flats taken as an example. (J.S.)
International Nuclear Information System (INIS)
As an effort to achieve efficient yet accurate transport transient calculations for power reactors, the conditional transport update scheme in method of characteristics (MOC) based coarse mesh finite difference (CMFD) transient calculation is developed. In this scheme, the transport calculations serves as an online group constant generator for the 3-D CMFD transient calculation and the solution of 3-D transient problem is mainly obtained from the 3-D CMFD transient calculation. In order to reduce the computational burden of the intensive transport calculation, the transport updates is conditionally performed by monitoring change of composition and core condition. This efficient transient transport method is applied to 3x3 assembly rod ejection problem to examine the effectiveness and accuracy of the conditional transport calculation scheme. (author)
Institute of Scientific and Technical Information of China (English)
张文娟; 黄守道; 高剑; CHEN; Zhe
2013-01-01
An analytic electromagnetic calculation method for doubly fed induction generator(DFIG) in wind turbine system was presented. Based on the operation principles, steady state equivalent circuit and basic equations of DFIG, the modeling for electromagnetic calculation of DFIG was proposed. The electromagnetic calculation of DFIG was divided into three steps: the magnetic flux calculation, parameters derivation and performance checks. For each step, the detailed numeric calculation formulas were all derived. Combining the calculation formulas, the whole electromagnetic calculation procedure was established, which consisted of three iterative calculation loops, including magnetic saturation coefficient, electromotive force and total output power. All of the electromagnetic and performance data of DIFG can be calculated conveniently by the established calculation procedure, which can be used to evaluate the new designed machine. A 1.5 MW DFIG designed by the proposed procedure was built, for which the whole type tests including no-load test, load test and temperature rising test were carried out. The test results have shown that the DFIG satisfies technical requirements and the test data fit well with the calculation results which prove the correctness of the presented calculation method.
A Discussion about Reducing the Amount of Calculation of Direct Method
Institute of Scientific and Technical Information of China (English)
DUTai-sheng; XIAOZe-chang
2003-01-01
The general interpolation mentioned in this article provides an effective way for reducing the amount of calculation of direct optimal exploration. It has been testified by real case calculations that the interpolation is not only reliable but also can save the amount of calculation by nearly 36 %. Large amount of calculation and lacking strict theoretical basis has been the two disadvantage of direct method by new. If this defect is not overcome, they will not only seriously affect the application of this meth-od, but also hinder its further research. Based on sufficient calculation practice, this article has made a primary discussion about the theory and method of reducing the amount of calculation, and has achieved some satisfactory results.
The method of calculation of radiation stimulated diffusion coefficients of impurities in silicon
International Nuclear Information System (INIS)
The simplified method of calculation of radiation stimulated diffusion coefficients of impurities in semiconductors like calculation method of 'dilution' of lithium diffusion profile in silicon because of drift at 400 K is proposed. The diffusion coefficients of lithium and zinc in silicon under the action of cobalt-60 gamma-rays and gamma-neutron irradiation were determined. The method developed can be applied also in the case of electron and proton irradiation. With the use of this method the change of p-n junction level because of irradiation and correspondingly the degradation of main characteristics of photoelectrical converters can be calculated. (A.D. Avezov). 7 refs.; 2 figs.; 1 tab
Monte Carlo simulation in the reaction rate's calculation with neutron-activation method
International Nuclear Information System (INIS)
With MCNP/4B code, the influence of cut-off energy, flux tallies, nuclear databases and perturbation on the reaction rate's calculation with neutron-activation method are analysed. When the effective reaction threshold is chosen as the cut-off energy, calculation time is considerably reduced and yet the results are not changed. Comparing calculations with cell tallies (F4) with those performed with detector tallies (F5), the counting efficiency of cell tallies is higher and the results are slightly higher, but still credible. With different nuclear databases, calculated results can be different. The perturbation among the detectors doesn't effect on the calculated results. (authors)
Hamming method for solving the delayed neutron precursor concentration for reactivity calculation
International Nuclear Information System (INIS)
Highlights: ► We present a new formulation to calculate the reactivity using the Hamming method. ► This method shows better accuracy than existing methods for reactivity calculation. ► The reactivity is calculated without limitation of the nuclear power form. ► The method can be implemented in reactivity meters with time step of up to 0.1 s. - Abstract: We propose a new method for numerically solving the inverse point kinetic equation for a nuclear reactor using the Hamming method, without requiring the nuclear power history and without using the Laplace transform. This new method converges with accuracy of order h5, where h is the step in the computation time. The procedure is validated for different forms of the nuclear power and with different time steps. The results indicate that this method has a better accuracy and lower computational effort compared with other conventional methods that use the nuclear power history.
Maskew, B.
1976-01-01
A discrete singularity method has been developed for calculating the potential flow around two-dimensional airfoils. The objective was to calculate velocities at any arbitrary point in the flow field, including points that approach the airfoil surface. That objective was achieved and is demonstrated here on a Joukowski airfoil. The method used combined vortices and sources ''submerged'' a small distance below the airfoil surface and incorporated a near-field subvortex technique developed earlier. When a velocity calculation point approached the airfoil surface, the number of discrete singularities effectively increased (but only locally) to keep the point just outside the error region of the submerged singularity discretization. The method could be extended to three dimensions, and should improve nonlinear methods, which calculate interference effects between multiple wings, and which include the effects of force-free trailing vortex sheets. The capability demonstrated here would extend the scope of such calculations to allow the close approach of wings and vortex sheets (or vortices).
Simple energy-calculation method for solar industrial-process-heat steam systems
Gee, R. C.
1983-01-01
Designing a solar industrial process heat (IPH) system, sizing its components and predicting its annual energy delivery requires a method for calculating solar system performance. A calculation method that is accurate, easy to use, accounts for the impact of all important system parameters, and does not require use of a computer is described. Only simple graphs and a hand calculator are required to predict annual collector field performance and annual system losses. The energy calculation method is applicable to a variety of solar system configurations. The calculation method applied only to parabolic trough steam generation systems that do not employ thermal storage is described. Both flash tank and unfired boiler steam systems are covered.
Xie, Hang; Sha, Wei E I
2015-01-01
Numerical methods are developed in the quantum transport calculations for electron in the waveguides with spin-orbital (Rashba) interaction. The methods are based on a hybrid mode-matching scheme in which the wavefunctions are expressed as the superposition of eigenmodes in the lead regions and in the device region the wavefunction is expressed on the discrete basis. Two versions are presented for the lead without and with the Rashba interaction. In the latter case the eigenmodes are obtained from a quadratic eigenproblem calculation. These methods are suitable for the systems with variable geometries or arbitrary potential profiles. The computation can be effectively accelerated by the sparse matrix technique. We also investigate the Fano-Rashba bound states in the Rashba waveguides by some nonlinear eigenstate calculation. This calculation is based on a mode-matching method and self-consistent results are obtained in our calculations.
Presentation of an in-operation failure rate calculation method from an event data bank
International Nuclear Information System (INIS)
This paper shortly describes a calculation method of a component failure rate during operation, from an event data bank. This method is validated by comparing the results obtained with those issued from a reliability data bank. The main interest of this method is to permit an enrichment of reliability data. Further development required needs to take account of ageing effects in this method. (orig.)
Methods of Cost Accounting and Production Costs Calculation: Merits and Demerits
Alla Pohosova; Olena Yarmolyuk
2012-01-01
The methods of cost accounting and calculation of production costs, including standard-cost, direct-costing, re-distribution and customized ones, their advantages and disadvantages have been analyzed. The proposals on the implementation of methods of cost accounting and production cost calculation in agricultural enterprises have been given. In addition, the application of the combined method of cost accounting of dairy cattle-breeding output has been accentuated
A new finite cloud method for calculating external exposure dose in a nuclear emergency
International Nuclear Information System (INIS)
A new finite cloud method (5/μ method) for calculating external exposure dose in a nuclear emergency is presented in this paper. The method calculates external exposure dose over a specially constructed three-dimensional columned space, whose underside center is the location of the receptor and underside radius and height are both five times mean free path of a gamma-photon. Then, the space is divided into many grid cells for integral to calculate external exposure dose (or dose rate). The calculation values of air external exposure dose rate conversion factors and air-absorbed dose rate conversion factors by the 5/μ method are accordant with the values presented in related references. Comparing with the discrete point approximation method (DPA) [USNRC, The MESORAD Dose Assessment Model. NUREG/CR-4000 Vol. 1, 1986] and the Nomogram method [USNRC, Nomogram for Evaluation of Doses from Finite Noble Gas Clouds, NUREG-0851, 1983], which are two traditional finite cloud methods for calculating external exposure dose, the 5/μ method has a distinct advantage of more fast calculation speed, which is very important in a nuclear emergency. What is more, the 5/μ method can be applied together with three-dimensional atmospheric dispersion models
A new finite cloud method for calculating external exposure dose in a nuclear emergency
Energy Technology Data Exchange (ETDEWEB)
Wang, X.Y.; Ling, Y.S. E-mail: lingyongsheng00@mails.tsinghua.edu.cn; Shi, Z.Q
2004-06-01
A new finite cloud method (5/{mu} method) for calculating external exposure dose in a nuclear emergency is presented in this paper. The method calculates external exposure dose over a specially constructed three-dimensional columned space, whose underside center is the location of the receptor and underside radius and height are both five times mean free path of a gamma-photon. Then, the space is divided into many grid cells for integral to calculate external exposure dose (or dose rate). The calculation values of air external exposure dose rate conversion factors and air-absorbed dose rate conversion factors by the 5/{mu} method are accordant with the values presented in related references. Comparing with the discrete point approximation method (DPA) [USNRC, The MESORAD Dose Assessment Model. NUREG/CR-4000 Vol. 1, 1986] and the Nomogram method [USNRC, Nomogram for Evaluation of Doses from Finite Noble Gas Clouds, NUREG-0851, 1983], which are two traditional finite cloud methods for calculating external exposure dose, the 5/{mu} method has a distinct advantage of more fast calculation speed, which is very important in a nuclear emergency. What is more, the 5/{mu} method can be applied together with three-dimensional atmospheric dispersion models.
A New Power Calculation Method for Single-Phase Grid-Connected Systems
DEFF Research Database (Denmark)
Yang, Yongheng; Blaabjerg, Frede
2013-01-01
A new method to calculate average active power and reactive power for single-phase systems is proposed in this paper. It can be used in different applications where the output active power and reactive power need to be calculated accurately and fast. For example, a grid-connected photovoltaic...... system in low voltage ride through operation mode requires a power feedback for the power control loop. Commonly, a Discrete Fourier Transform (DFT) based power calculation method can be adopted in such systems. However, the DFT method introduces at least a one-cycle time delay. The new power calculation...... method, which is based on the adaptive filtering technique, can achieve a faster response. The performance of the proposed method is verified by experiments and demonstrated in a 1 kW single-phase grid-connected system operating under different conditions.Experimental results show the effectiveness of...
Improvement of accuracy of resonance self-shielding calculation based on subgroup method
International Nuclear Information System (INIS)
Based on the neutron self-shielding calculation code SGMOC, which is the combination of subgroup method and characteristics method that developed by ourselves, we studied the two techniques to improve the SGMOC calculation accuracy. The numerical results prove that both techniques have the capability to improve the resonance self-shielding calculation accuracy. The resonance interference effect treatment which uses a new method to obtain the conditional probabilities, has a correction effect about 20∼230 pcm. When the impact of the resonance scattering is considered, the correction effect is about 100 Dcm. When utilizing the above two techniques simultaneously, the correction effect is about 30∼270 pcm. (authors)
Calculation methods for SPF for heat pump systems for comparison, system choice and dimensioning
Energy Technology Data Exchange (ETDEWEB)
Nordman, Roger; Andersson, Kajsa; Axell, Monica; Lindahl, Markus
2010-09-15
In this project, results from field measurements of heat pumps have been collected and summarised. Also existing calculation methods have been compared and summarised. Analyses have been made on how the field measurements compare to existing calculation models for heat pumps Seasonal Performance Factor (SPF), and what deviations may depend on. Recommendations for new calculation models are proposed, which include combined systems (e.g. solar - HP), capacity controlled heat pumps and combined DHW and heating operation
Directory of Open Access Journals (Sweden)
Shan Yang
2016-01-01
Full Text Available Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverter based distributed generation is proposed. The proposed method let the inverter based distributed generation be equivalent to Iθ bus, which makes it suitable to calculate the power flow of distribution network with a current limited inverter based distributed generation. And the low voltage ride through capability of inverter based distributed generation can be considered as well in this paper. Finally, some tests of power flow and short circuit current calculation are performed on a 33-bus distribution network. The calculated results from the proposed method in this paper are contrasted with those by the traditional method and the simulation method, whose results have verified the effectiveness of the integrated method suggested in this paper.
Calculation of neutron importance function in fissionable assemblies using Monte Carlo method
International Nuclear Information System (INIS)
The purpose of the present work is to develop an efficient solution method to calculate neutron importance function in fissionable assemblies for all criticality conditions, using Monte Carlo Method. The neutron importance function has a well important role in perturbation theory and reactor dynamic calculations. Usually this function can be determined by calculating adjoint flux through out solving the Adjoint weighted transport equation with deterministic methods. However, in complex geometries these calculations are very difficult. In this article, considering the capabilities of MCNP code in solving problems with complex geometries and its closeness to physical concepts, a comprehensive method based on physical concept of neutron importance has been introduced for calculating neutron importance function in sub-critical, critical and supercritical conditions. For this means a computer program has been developed. The results of the method has been benchmarked with ANISN code calculations in 1 and 2 group modes for simple geometries and their correctness has been approved for all three criticality conditions. Ultimately, the efficiency of the method for complex geometries has been shown by calculation of neutron importance in MNSR research reactor
A method for numerical calculation of propeller hydrodynamics in unsteady inflow
Institute of Scientific and Technical Information of China (English)
HUANG Sheng; WANG Pei-sheng; HU Jian
2007-01-01
The hydrodynamic performance of a propeller in unsteady inflow was calculated using the surface panel method. The surfaces of blades and hub were discreted by a number of hyperboloidal quadrilateral panels with constant source and doublet distribution. Each panel's comer coordinates were calculated by spline interpolation between the main parameter and the blade geometry of the propeller.The integral equation was derived using the Green Formula.The influence coefficient of the matrix was calculated by the Morino analytic formula. The tangential velocity distribution was calculated with the Yanagizawa method, and the pressure coefficient was calculated using the Bonuli equation. The pressure Kutta condition was satisfied at the trailing edge of the propeller blade using the Newton-Raphson iterative procedure, so as to make the pressure coefficients of the suction and pressure faces of the blade equal at the trailing edge. Calculated results for the propeller in steady inflow were taken as initialization values for the unsteady inflow calculation process. Calculations were carried out from the moment the propeller achieved steady rotation. At each time interval, a linear algebraic equation combined with Kutta condition was established on a key blade and solved numerically. Comparison between calculated results and experimental results indicates that this method is correct and effective.
Applying Activity Based Costing (ABC Method to Calculate Cost Price in Hospital and Remedy Services
Directory of Open Access Journals (Sweden)
A Dabiri
2012-04-01
Full Text Available Background: Activity Based Costing (ABC is one of the new methods began appearing as a costing methodology in the 1990. It calculates cost price by determining the usage of resources. In this study, ABC method was used for calculating cost price of remedial services in hospitals.Methods: To apply ABC method, Shahid Faghihi Hospital was selected. First, hospital units were divided into three main departments: administrative, diagnostic, and hospitalized. Second, activity centers were defined by the activity analysis method. Third, costs of administrative activity centers were allocated into diagnostic and operational departments based on the cost driver. Finally, with regard to the usage of cost objectives from services of activity centers, the cost price of medical services was calculated.Results: The cost price from ABC method significantly differs from tariff method. In addition, high amount of indirect costs in the hospital indicates that capacities of resources are not used properly.Conclusion: Cost price of remedial services with tariff method is not properly calculated when compared with ABC method. ABC calculates cost price by applying suitable mechanisms but tariff method is based on the fixed price. In addition, ABC represents useful information about the amount and combination of cost price services.
Four Methods for Calculating Blood-loss after Total Knee Arthroplasty
Institute of Scientific and Technical Information of China (English)
Fu-Qiang Gao; Zi-Jian Li; Ke Zhang; Wei Sun; Hong Zhang
2015-01-01
Background:Currently,various calculation methods for evaluating blood-loss in patients with total knee arthroplasty (TKA) are applied in clinical practice.However,different methods may yield different results.The purpose of this study was to determine the most reliable method for calculating blood-loss after primary TKA.Methods:We compared blood-loss in 245 patients who underwent primary unilateral TKA from February 2010 to August 2011.We calculated blood-loss using four methods:Gross equation,hemoglobin (Hb) balance,the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula,and Hb-dilution.We determined Pearson's correlation coefficients for the four methods.Results:There were large differences in the calculated blood-loss obtained by the four methods.In descending order of combined correlation coefficient based on calculated blood-loss,the methods were Hb-balance,OSTHEO formula,Hb-dilution,and Gross equation.Conclusions:The Hb-balance method may be the most reliable method of estimating blood-loss after TKA.
International Nuclear Information System (INIS)
This report documents the research and development goals reached within the reactor safety research project RS1503 ''Development and Application of Neutron Transport Methods and Uncertainty Analyses for Reactor Core Calculations''. The superordinate goal of the project is the development, validation, and application of neutron transport methods and uncertainty analyses for reactor core calculations. These calculation methods will mainly be applied to problems related to the core behaviour of light water reactors and innovative reactor concepts. The contributions of this project towards achieving this goal are the further development, validation, and application of deterministic and stochastic calculation programmes and of methods for uncertainty and sensitivity analyses, as well as the assessment of artificial neutral networks, for providing a complete nuclear calculation chain. This comprises processing nuclear basis data, creating multi-group data for diffusion and transport codes, obtaining reference solutions for stationary states with Monte Carlo codes, performing coupled 3D full core analyses in diffusion approximation and with other deterministic and also Monte Carlo transport codes, and implementing uncertainty and sensitivity analyses with the aim of propagating uncertainties through the whole calculation chain from fuel assembly, spectral and depletion calculations to coupled transient analyses. This calculation chain shall be applicable to light water reactors and also to innovative reactor concepts, and therefore has to be extensively validated with the help of benchmarks and critical experiments.
A modified Gaussian integration method for thermal reaction rate calculation in U- and Pu-isotopes
International Nuclear Information System (INIS)
An advanced multi-group cell calculations a lot of data information is very often necessary, and hence the data administration will be elaborate, and the spectrum calculation will be time consuming. We think it is possible to reduce the necessary data information by using an effective reaction rate integration method well suited for U- and Pu-absorptions (author)
The ion exchange and its connection the industry II.- Calculation methods for installations
International Nuclear Information System (INIS)
An exposure is made of calculation methods for ion exchange installations based on kinetic considerations and similarity with other unitary operations. Factors to be experimentally obtained as well as difficulties which may occur in its determination are also given. Calculation procedures most commonly used in industry are enclosed and explained with numerical resolution of a problem of water demineralization. (Author) 22 refs
A Simple and Convenient Method of Multiple Linear Regression to Calculate Iodine Molecular Constants
Cooper, Paul D.
2010-01-01
A new procedure using a student-friendly least-squares multiple linear-regression technique utilizing a function within Microsoft Excel is described that enables students to calculate molecular constants from the vibronic spectrum of iodine. This method is advantageous pedagogically as it calculates molecular constants for ground and excited…
Energy Technology Data Exchange (ETDEWEB)
Perfetti, C.; Martin, W. [Univ. of Michigan, Dept. of Nuclear Engineering and Radiological Sciences, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104 (United States); Rearden, B.; Williams, M. [Oak Ridge National Laboratory, Reactor and Nuclear Systems Div., Bldg. 5700, P.O. Box 2008, Oak Ridge, TN 37831-6170 (United States)
2012-07-01
Three methods for calculating continuous-energy eigenvalue sensitivity coefficients were developed and implemented into the Shift Monte Carlo code within the SCALE code package. The methods were used for two small-scale test problems and were evaluated in terms of speed, accuracy, efficiency, and memory requirements. A promising new method for calculating eigenvalue sensitivity coefficients, known as the CLUTCH method, was developed and produced accurate sensitivity coefficients with figures of merit that were several orders of magnitude larger than those from existing methods. (authors)
Integral method for the calculation of three-dimensional, laminar and turbulent boundary layers
Stock, H. W.
1978-01-01
The method for turbulent flows is a further development of an existing method; profile families with two parameters and a lag entrainment method replace the simple entrainment method and power profiles with one parameter. The method for laminar flows is a new development. Moment of momentum equations were used for the solution of the problem, the profile families were derived from similar solutions of boundary layer equations. Laminar and turbulent flows at the wings were calculated. The influence of wing tapering on the boundary layer development was shown. The turbulent boundary layer for a revolution ellipsoid is calculated for 0 deg and 10 deg incidence angles.
International Nuclear Information System (INIS)
Highlights: • A GPT-based method is applied to resonance cross sections sensitivity calculation. • The subgroup resonance-calculation method is employed. • The method is validated against DP method for two different cases. • The impact of implicit sensitivity on eigenvalue uncertainty is investigated. - Abstract: Response sensitivity coefficients with respect to nuclide cross sections consist of two parts, explicit sensitivity coefficients and implicit sensitivity coefficients. The explicit sensitivity coefficients, which account the direct impact of cross sections on the responses through neutron transport equation, can be calculated efficiently with the classical Perturbation Theory. The implicit sensitivity coefficients, which account the indirect impact of cross sections on the responses through resonance self-shielding, are either omitted in most sensitivity analysis codes, or accounted for based on simple resonance-calculation methods which are not applicable for complex fuel designs. In order to expand the implicit sensitivity analysis method to wider application domain, a method based on the Generalized Perturbation Theory (GPT) is proposed in this paper to calculate the implicit sensitivity coefficients by using the subgroup method in the resonance self-shielding calculation. Based on the in-house-developed 2-D general-geometry method-of-characteristic neutron-transport code AutoMOC and subgroup resonance self-shielding code SUGAR, the proposed method has been implemented in the COLEUS code for the sensitivity and uncertainty analysis. Numerical analysis is then performed to investigate the impact of the implicit sensitivity coefficients of eigenvalue on non-resonance nuclide cross sections in two single-cell cases with different enrichments. The eigenvalue sensitivity coefficients predicted by the COLEUS code are consistent with those calculated by the direct-perturbation method, the reference solution. The results show that the implicit
Universal method of strictly calculating self-consistent fields of realistic plasma particles
H. Lin
2010-01-01
A universal method of strictly calculating self-consistent fields of realistic plasma particles could be strictly derived from three basic tools in theoretical plasma physics: particle simulation, Vlasov-Maxwell theory and fluid theory.
Improved method of generating bit reversed numbers for calculating fast fourier transform
Digital Repository Service at National Institute of Oceanography (India)
Suresh, T.
Fast Fourier Transform (FFT) is an important tool required for signal processing in defence applications. This paper reports an improved method for generating bit reversed numbers needed in calculating FFT using radix-2. The refined algorithm takes...
The adaptation of methods in multilayer optics for the calculation of specular neutron reflection
International Nuclear Information System (INIS)
The adaptation of standard methods in multilayer optics to the calculation of specular neutron reflection is described. Their application is illustrated with examples which include a glass optical flat and a deuterated Langmuir-Blodgett film. (author)
Calculation of neutron transport in plane geometry by invariant imbedding method
International Nuclear Information System (INIS)
A practical combination of invariant imbedding and transfer matrix methods was displayed in this paper. A very simple scheme for neutron transport analysis was obtained for slab materials and some results of numerical calculations are presented. (author)
International Nuclear Information System (INIS)
Sensitivity and uncertainty calculations methods of neutronics parameters in pressurized light water reactors have been developed. The sensitivity is composed of three terms; the first is the sensitivity of cell-averaged multi-group cross-sections relative to multi-group infinite dilution cross-sections, the second is the sensitivity of assembly averaged few-group macroscopic cross-sections relative to cell-averaged multi-group cross-sections, and the third is the sensitivity of neutronics parameters in PWR cores relative to few-group macroscopic cross-sections. Combining the three sensitivities, the sensitivity of neutronics parameters in PWR cores relative to multi-group infinite dilution cross-sections is obtained. The discussion of this method will be presented in two papers; the present paper is part I, where the theory and some numerical results for typical pin cells, fuel assemblies and a simple PWR core are shown. The present method gives us multi-group sensitivities for individual nuclides in each reaction type, and wide ranges of applications are possible to the fields such as cross-section adjustment and uncertainty reduction. (author)
A FINITE-DIFFERENCE, DISCRETE-WAVENUMBER METHOD FOR CALCULATING RADAR TRACES
A hybrid of the finite-difference method and the discrete-wavenumber method is developed to calculate radar traces. The method is based on a three-dimensional model defined in the Cartesian coordinate system; the electromagnetic properties of the model are symmetric with respect ...
Investigation of light propagation methods used to calculate wave-optical PSF
Horiuchi, Shuma; Yoshida, Shuhei; Yamamoto, Manabu
2015-09-01
In this study, we investigated the suitability of various light propagation methods and their usefulness in terms of calculating the wave-optical point spread function (PSF) of an optical imaging system. To analyze an aberration in an optical imaging system in order to obtain its PSF, light propagation methods are widely used to obtain the light intensity distribution on the observation plane. Both the Fresnel-Kirchhoff and Rayleigh-Sommerfeld diffraction formulae are commonly used in light propagation simulations. Recently, there have been many reports concerning light propagation methods in the field of digital holography. These methods are based on the Rayleigh-Sommerfeld diffraction formula and use discrete Fourier transformation. These methods are referred to as the angular spectrum and Fresnel diffraction methods. In this study, these propagation methods are evaluated in terms of the degree of accuracy offered and their associated calculation costs. In order to demonstrate and investigate the features of these propagation methods, we employed a Tessar lens system, which is composed of four lenses. The wavefront aberration of the lens system is obtained by a ray tracing simulation and is used to generate the generalized pupil function. Next, the Rayleigh- Sommerfeld diffraction formula and the light propagation method based on this formula are used to calculate the waveoptical PSF using the pupil function. We applied these simulation methods to various recently proposed propagation methods and discussed the suitability of the various light propagation methods under consideration for calculating the wave-optical PSF.
Calculation of isotopic mass and energy production by a matrix operator method
International Nuclear Information System (INIS)
The Volterra method of the multiplicative integral is used to determine the isotopic density, mass, and energy production in linear systems. The solution method, assumptions, and limitations are discussed. The method allows a rapid accurate calculation of the change in isotopic density, mass, and energy production independent of the magnitude of the time steps, production or decay rates, or flux levels
COMPLEX INNER PRODUCT AVERAGING METHOD FOR CALCULATING NORMAL FORM OF ODE
Institute of Scientific and Technical Information of China (English)
陈予恕; 孙洪军
2001-01-01
This paper puts forward a complex inner product averaging method for calculating normal form of ODE. Compared with conventional averaging method, the theoretic analytical process has such simple forms as to realize computer program easily.Results can be applied in both autonomous and non-autonomous systems. At last, an example is resolved to verify the method.
International Nuclear Information System (INIS)
Applicability of the cross section adjustment method based on random sampling (RS) technique to burnup calculations is investigated. The cross section adjustment method is a technique for reduction of prediction uncertainties in reactor core analysis and has been widely applied to fast reactors. As a practical method, the cross section adjustment method based on RS technique is newly developed for application to light water reactors (LWRs). In this method, covariance among cross sections and neutronics parameters are statistically estimated by the RS technique and cross sections are adjusted without calculation of sensitivity coefficients of neutronics parameters, which are necessary in the conventional cross section adjustment method. Since sensitivity coefficients are not used, the RS-based method is expected to be practically applied to LWR core analysis, in which considerable computational costs are required for estimation of sensitivity coefficients. Through a simple pin-cell burnup calculation, applicability of the present method to burnup calculations is investigated. The calculation results indicate that the present method can adequately adjust cross sections including burnup characteristics. (author)
Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy
International Nuclear Information System (INIS)
The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.
Energy Technology Data Exchange (ETDEWEB)
Cheng-Yang Tan
2001-07-30
We will show in this paper a method for calculating the longitudinal phase space distribution when the time profile of the bunch as measured by a wall current monitor is given. The key to this method is the assumption that the bunch is matched to the bucket. With this assumption, we will show that the method boils down to solving a simple upper triangular matrix equation. We will also illustrate the method with two examples and show the method's shortcomings.
Assessment of formulas for calculating critical concentration by the agar diffusion method.
Drugeon, H.B.; Juvin, M E; Caillon, J.; Courtieu, A L
1987-01-01
The critical concentration of antibiotic was calculated by using the agar diffusion method with disks containing different charges of antibiotic. It is currently possible to use different calculation formulas (based on Fick's law) devised by Cooper and Woodman (the best known) and by Vesterdal. The results obtained with the formulas were compared with the MIC results (obtained by the agar dilution method). A total of 91 strains and two cephalosporins (cefotaxime and ceftriaxone) were studied....
Sørensen, R.; Zinko, U.; Seibert, J.
2005-01-01
The topographic wetness index (TWI, ln(a/tanβ)), which combines local upslope contributing area and slope, is commonly used to quantify topographic control on hydrological processes. Methods of computing this index differ primarily in the way the upslope contributing area is calculated. In this study we compared a number of calculation methods for TWI and evaluated them in terms of their correlation with the following measured variables: vascular plant species richness, soil pH, groundwa...
Analytical method for calculation of navigational data for the position of a satellite
Lala, P.
1975-01-01
A method is described for calculating the position of a satellite at the instants when measurements are made on board. The initial conditions used were the mean orbital elements of the satellite and their time derivatives in one orbit. The results of the calculation are compared with those obtained by numerical integration, and it is found that results are identical at the beginning of an orbit, but change as the orbit progresses. The advantages and disadvantages of the analytical method are presented.
Excited States Calculated by Means of the Linear Muffin-Tin Orbital Method
Alouani, M.; Wills, J M
1999-01-01
The most popular electronic structure method, the linear muffin-tin orbital method (LMTO), in its full-potential (FP) and relativistic forms has been extended to calculate the spectroscopic properties of materials form first principles, i.e, optical spectra, x-ray magnetic circular dichroism (XMCD) and magneto-optical kerr effect (MOKE). The paper describes an overview of the FP-LMTO basis set and the calculation of the momentum matrix elements. Some applications concerning the computation of...
Saeed Hatamzadeh-Varmazyar; Zahra Masouri
2014-01-01
The focus of this article is on calculation of electrostatic charge distribution induced on conducting surfaces. For this purpose, the integral equation concept is used for mathematical modeling of the problem. A special set of exponential basis functions is introduced and defined to be used in formulation of a numerical method for solving the integral equation to obtain the charge distribution. The method is numerically evaluated via calculation of charge density for some structures by which...
New method for calculation of the Vander-Walls interaction constants
International Nuclear Information System (INIS)
A new method is proposed for calculating dispersion coefficients. The method is based on a qualitative idea of quasiclassic system of N particles within the limit of large d-dimensions of space. Pade-approximation enables to sum up efficiently the series of 1/d-decomposition and derive expressions for Van-der-Walls coefficients. Corrections related to nuclear mass finiteness are also calculated
Comparison of forest machine cost calculation methods on the case of a cableway
Klun, Jaka; Košir, Boštjan; Krč, Janez; Medved, Mirko
2007-01-01
The paper presents results of a comparison of seven different machine cost calculation methods presently used mainly in forest operations cost calculations. The compared methods have a common basis structure, but differ in methodology and item consideration. From the premise of equal inputs and byconsidering yearly productive time on the case of a cableway, the comparisonshows differences in machine costs and thus lesser comparability of machine economy per product unit. Input data for the co...
An altenative pseudo-harmonics method: application to two-dimensional reactor calculations
International Nuclear Information System (INIS)
An alternative to the pseudo-harmonics method of computing two-dimensional perturbed states of nuclear reactors is presented, together with some results of neutron flux reconstruction and eigenvalue calculation. These results refer to intense localized perturbations, where a significant imbalance between production and destruction rates exists. Previous methods have presented convergence problems. The alternative described was able to overcome these problems and is thus considered to be very promising for two-dimensional calculations. (author)
International Nuclear Information System (INIS)
Highlights: • The stiffness confinement method is combined with multigroup CMFD with SENM nodal kernel. • The systematic methods for determining the shape and amplitude frequencies are established. • Eigenvalue problems instead of fixed source problems are solved in the transient calculation. • It is demonstrated that much larger time step sizes can be used with the SCM–CMFD method. - Abstract: An improved Stiffness Confinement Method (SCM) is formulated within the framework of the coarse mesh finite difference (CMFD) formulation for efficient multigroup spatial kinetics calculation. The algorithm for searching for the amplitude frequency that makes the dynamic eigenvalue unity is developed in a systematic way along with the methods for determining the shape and precursor frequencies. A nodal calculation scheme is established within the CMFD framework to incorporate the cross section changes due to thermal feedback and dynamic frequency update. The conditional nodal update scheme is employed such that the transient calculation is performed mostly with the CMFD formulation and the CMFD parameters are conditionally updated by intermittent nodal calculations. A quadratic representation of amplitude frequency is introduced as another improvement. The performance of the improved SCM within the CMFD framework is assessed by comparing the solution accuracy and computing times for the NEACRP control rod ejection benchmark problems with those obtained with the Crank–Nicholson method with exponential transform (CNET). It is demonstrated that the improved SCM is beneficial for large time step size calculations with stability and accuracy enhancement
Directory of Open Access Journals (Sweden)
R. Sørensen
2006-01-01
Full Text Available The topographic wetness index (TWI, ln(a/tanβ, which combines local upslope contributing area and slope, is commonly used to quantify topographic control on hydrological processes. Methods of computing this index differ primarily in the way the upslope contributing area is calculated. In this study we compared a number of calculation methods for TWI and evaluated them in terms of their correlation with the following measured variables: vascular plant species richness, soil pH, groundwater level, soil moisture, and a constructed wetness degree. The TWI was calculated by varying six parameters affecting the distribution of accumulated area among downslope cells and by varying the way the slope was calculated. All possible combinations of these parameters were calculated for two separate boreal forest sites in northern Sweden. We did not find a calculation method that performed best for all measured variables; rather the best methods seemed to be variable and site specific. However, we were able to identify some general characteristics of the best methods for different groups of measured variables. The results provide guiding principles for choosing the best method for estimating species richness, soil pH, groundwater level, and soil moisture by the TWI derived from digital elevation models.
International Nuclear Information System (INIS)
This document serves as a guide to Hanford contractors for obtaining or performing Hanford-related environmental dose calculations. Because environmental dose estimation techniques are state-of-the-art and are continually evolving, the data and standard methods presented herein will require periodic revision. This document is scheduled to be updated annually, but actual changes to the program will be made more frequently if required. For this reason, PNL's Occupational and Environmental Protection Department should be contacted before any Hanford-related environmental dose calculation is performed. This revision of the Hanford Dose Overview Program Report primarily reflects changes made to the data and models used in calculating atmospheric dispersion of airborne effluents at Hanford. The modified data and models are described in detail. In addition, discussions of dose calculation methods and the review of calculation results have been expanded to provide more explicit guidance to the Hanford contractors. 19 references, 30 tables
Calculation reduction method for color computer-generated hologram using color space conversion
Shimobaba, Tomoyoshi; Oikawa, Minoru; Takada, Naoki; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Ito, Tomoyoshi
2013-01-01
We report a calculation reduction method for color computer-generated holograms (CGHs) using color space conversion. Color CGHs are generally calculated on RGB space. In this paper, we calculate color CGHs in other color spaces: for example, YCbCr color space. In YCbCr color space, a RGB image is converted to the luminance component (Y), blue-difference chroma (Cb) and red-difference chroma (Cr) components. In terms of the human eye, although the negligible difference of the luminance component is well-recognized, the difference of the other components is not. In this method, the luminance component is normal sampled and the chroma components are down-sampled. The down-sampling allows us to accelerate the calculation of the color CGHs. We compute diffraction calculations from the components, and then we convert the diffracted results in YCbCr color space to RGB color space.
Structural system reliability calculation using a probabilistic fault tree analysis method
Torng, T. Y.; Wu, Y.-T.; Millwater, H. R.
1992-01-01
The development of a new probabilistic fault tree analysis (PFTA) method for calculating structural system reliability is summarized. The proposed PFTA procedure includes: developing a fault tree to represent the complex structural system, constructing an approximation function for each bottom event, determining a dominant sampling sequence for all bottom events, and calculating the system reliability using an adaptive importance sampling method. PFTA is suitable for complicated structural problems that require computer-intensive computer calculations. A computer program has been developed to implement the PFTA.
International Nuclear Information System (INIS)
Calculation of the vibrational spectral for the large molecule of fullerene. C60, has been carried out by the efficient quantum mechanical methods. In this work the ab initio selected calculation methods were Gaussian 98 program with the STO-3G basis set and HYPER 7 program with PM3 and AM1. The heat capacity, at constant volume has been calculated based on the separation of the vibrational spectrum into group and molecular vibrations. Besides the heat capacity, at constant pressure was obtained by the Nernst-Lindemann modified equation
Ermis Elif Ebru; Celiktas Cuneyt
2015-01-01
Calculations of gamma-ray mass attenuation coefficients of various detector materials (crystals) were carried out by means of FLUKA Monte Carlo (MC) method at different gamma-ray energies. NaI, PVT, GSO, GaAs and CdWO4 detector materials were chosen in the calculations. Calculated coefficients were also compared with the National Institute of Standards and Technology (NIST) values. Obtained results through this method were highly in accordance with those of the NIST values. It was concluded f...
An improved method for calculating control rod reactivity worths in fast sodium cooled reactor cores
International Nuclear Information System (INIS)
An improved method is presented to determine the reactivities of strongly inhomogeneous control rod arrangements in fast sodium cooled reactor cores. The method is based on a detailed evaluation of the multiplication constants for the rods embedded in a large surrounding of fuel material. These calculations are performed using two-dimensional transport theory, with an accurate representation of the actual geometry in RΘ coordinates and with fine discretizations in coordinate space and energy. Three-dimensional whole core calculations are carried out in diffusion approximation, with a coarse spatial hexagonal-Z mesh and few energy groups, replacing the individual reactor cells by homogeneous arrangements. The homogenized macroscopic group cross sections are generated with standard methods, however using reduced boron contents of the absorber pins as compared with their actual values. The appropriate boron concentrations are found by comparing the control rod reactivity worths resulting from the two-dimensional transport calculations with those determined from corresponding diffusion calculations with homogenized compositions for the corresponding regions, which possess as many features of the final whole core calculations as possible. In this way, the corrections necessitated by the heterogeneity, transport, mesh, and condensation effects are incorporated in the macroscopic cross sections. With these as input, the computed rod worths of the secondary shutdown system of the SUPERPHENIX-1 (SPX-1) power production core are essentially improved as compared with results of earlier calculations. This progress of the calculational method is clearly demonstrated by a comparison with measured reactivity worths. (orig.)
A new method for the calculation of diffusion coefficients with Monte Carlo
International Nuclear Information System (INIS)
This paper presents a new Monte Carlo-based method for the calculation of diffusion coefficients. One distinctive feature of this method is that it does not resort to the computation of transport cross sections directly, although their functional form is retained. Instead, a special type of tally derived from a deterministic estimate of Fick's Law is used for tallying the total cross section, which is then combined with a set of other standard Monte Carlo tallies. Some properties of this method are presented by means of numerical examples for a multi-group 1-D implementation. Calculated diffusion coefficients are in general good agreement with values obtained by other methods. (author)
Resources calculation of cobalt-rich crusts with the grid subdivision and integral method
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
On the basis of three geological models and several orebody boundaries, a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the central Pacific Ocean. The formulas of this method are deduced and the interface of program module is designed. The method is carried out in the software "Auto mapping system of submarine topography and geomorphology MBChart". This method and program will possibly become a potential tool to calculate the resources of seamounts and determine the target diggings for China's next Five-year Plan.
A New Method for Calculating the Transfer Functions in Quasiresonant Converters
Directory of Open Access Journals (Sweden)
LASCU, M.
2013-08-01
Full Text Available A matrix method for deriving the audiosusceptibility and the control to output transfer functions in quasiresonant converters (QRCs is presented. The method is based on the state-space description of the parent converter and it has the advantage of generality in the sense it can be applied to any topology. Moreover, it can be easily absorbed in MATLAB under Symbolic Toolbox, substantially reducing the calculation effort and time. Using this method the control to output transfer function of the QRC Cuk converter is calculated for the first time. The method is verified compared to other tools and perfect agreement is observed for second order classical converters.
A New Method for the Calculation of Diffusion Coefficients with Monte Carlo
Dorval, Eric
2014-06-01
This paper presents a new Monte Carlo-based method for the calculation of diffusion coefficients. One distinctive feature of this method is that it does not resort to the computation of transport cross sections directly, although their functional form is retained. Instead, a special type of tally derived from a deterministic estimate of Fick's Law is used for tallying the total cross section, which is then combined with a set of other standard Monte Carlo tallies. Some properties of this method are presented by means of numerical examples for a multi-group 1-D implementation. Calculated diffusion coefficients are in general good agreement with values obtained by other methods.
International Nuclear Information System (INIS)
Estimating uncertainties on doses from bioassay data is of interest in epidemiology studies that estimate cancer risk from occupational exposures to radionuclides. Bayesian methods provide a logical framework to calculate these uncertainties. However, occupational exposures often consist of many intakes, and this can make the Bayesian calculation computationally intractable. This paper describes a novel strategy for increasing the computational speed of the calculation by simplifying the intake pattern to a single composite intake, termed as complex intake regime (CIR). In order to assess whether this approximation is accurate and fast enough for practical purposes, the method is implemented by the Weighted Likelihood Monte Carlo Sampling (WeLMoS) method and evaluated by comparing its performance with a Markov Chain Monte Carlo (MCMC) method. The MCMC method gives the full solution (all intakes are independent), but is very computationally intensive to apply routinely. Posterior distributions of model parameter values, intakes and doses are calculated for a representative sample of plutonium workers from the United Kingdom Atomic Energy cohort using the WeLMoS method with the CIR and the MCMC method. The distributions are in good agreement: posterior means and Q 0.025 and Q 0.975 quantiles are typically within 20 %. Furthermore, the WeLMoS method using the CIR converges quickly: a typical case history takes around 10-20 min on a fast workstation, whereas the MCMC method took around 12-hr. The advantages and disadvantages of the method are discussed. (authors)
Calculation Method for Flight Limit Load of V-band Clamp Separation Shock
Iwasa, Takashi; Shi, Qinzhong
A simplified calculation method for estimating a flight limit load of the V-band clamp separation shock was established. With this method, the flight limit load is estimated through addition of an appropriate envelope margin to the results acquired with the simplified analysis method proposed in our previous paper. The envelope margin used in the method was calculated based on the reviews on the differences observed between the results of a pyroshock test and the analysis. Using the derived envelope margin, a calculating formula of the flight limit load, which envelopes the actual pyroshock responses with a certain probability, was developed. Based on the formula, flight limit loads for several actual satellites were estimated and compared to the test results. The comparative results showed that the estimated flight limit loads appropriately envelope the test results, which confirmed the effectiveness of the proposed method.
Digital Breast Tomosynthesis: Comparison of Different Methods to Calculate Patient Doses
International Nuclear Information System (INIS)
Different methods have been proposed in the literature to calculate the dose to the patient's breast in 3-D mammography. The methods described by Dance et al. and Sechopoulos et al. have been compared in this study using the two tomosynthesis systems available in the authors' hospitals (Siemens and Hologic). There is a small but significant difference of 23% for the first X ray system and 13% for the second system between dose calculations performed with Dance's method and Sechopoulos' method. These differences are mainly due to the fact that the two sets of authors used different breast models for their Monte Carlo calculations. For each system, the calculated breast doses were compared with the dose values indicated on the system console. Good agreement was found when the method of Dance et al. was used for a breast glandularity based on the patient age. For the Siemens system, the calculated doses were 5% lower than the indicated dose and for the Hologic system, the calculated doses were 12% higher. Finally, the 3-D dose values were compared with the doses found in a large 2-D dosimetry study. The dose values for tomosynthesis on the Siemens system were almost double the doses in one view 2-D digital mammography. For a typical breast of thickness 45 mm, the dose of one 2-D view was 0.83 mGy and for one 3-D view 1.79 mGy. (author)
Ajiki, Hiroshi
2013-05-01
A new method for calculating exciton wavefunctions in the presence of a long-range electron--hole (e--h) exchange interaction (EXI) is presented. The e--h EXI arises, for example, for cross-polarized excitons in a single-walled carbon nanotube (SWNT). Cross-polarized excitons have previously been calculated as an eigenvalue problem of a Bethe--Salpeter equation (BSE) within the Tamm--Dancoff-type approximation (TDA). The resulting wavefunctions provide quite different absorption spectra in comparison with those calculated in the self-consistent-field method [S. Uryu and T. Ando, J. Phys.: Conf. Ser. 302 (2011) 012004]. Although the self-consistent-field method is more reliable, exciton wavefunctions cannot be obtained from this method. A general method is derived here to obtain exciton wavefunctions that take the e--h EXI into account within the TDA, and the method is applied to the cross-polarized excitons of a SWNT. The absorption spectra calculated from the resulting exciton wavefunctions agree well with the spectra calculated from the self-consistent-field method within a rotating-wave approximation.
Comparison of calculation methods for the tunnel splitting at excited states of biaxial spin models
Institute of Scientific and Technical Information of China (English)
Cui Xiao-Bo; Chen Zhi-De
2004-01-01
We present the calculation and comparison of tunnel splitting at excited levels of biaxial spin models by various methods, including the generalized instanton method, the generalized path integral method for coherent spin states,the perturbation method, and the exact method by numerical diagonalization of the Hamiltonian. It is found that,for integer spin with spin number around 10, tunnel splitting predicted by the generalized path integral for coherent spin states is about 10-n times of the exact numerical result for the nth excited level, while the ratio of the results of the perturbation method and the exact numerical method diverges in the large spin limit. We thus conclude that the generalized instanton method is the best approximate way for calculating tunnel splitting in spin models.
Ovchinnikov, Victor; Cecchini, Marco; Karplus, Martin
2013-01-01
A simple and robust formulation of the path-independent confinement method for the calculation of free energies is presented. The simplified confinement method (SCM) does not require matrix diagonalization or switching off the molecular force field, and has a simple convergence criterion. The method can be readily implemented in molecular dynamics programs with minimal or no code modifications. Because the confinement method is a special case of thermodynamic integration, it is trivially para...
Chock, Jeffrey Mun Kong
1999-01-01
Blast profiles and two primary methods of determining them were reviewed for use in the creation of a computer program for calculating blast pressures which serves as a design tool to aid engineers or analysts in the study of structures subjected to explosive air blast. These methods were integrated into a computer program, BLAST.F, to generate air blast pressure profiles by one of these two differing methods. These two methods were compared after the creation of the program and can conserv...
THE PARTICULARITIES OF THE COST CALCULATION METHOD ON COMMANDS IN FURNITURE INDUSTRY
Directory of Open Access Journals (Sweden)
Felicia Sabou
2014-10-01
Full Text Available The paper present the importance of the method on commands in cost calculation and the particularities of the cost calculation method on commands in the furniture industry. This paper presents a hypotetical study on the method on commands, considering the observations made during 2013-2014, on how it is organized and managed accounts management using method on commands.By presenting this hypothetical model about the accounting in management accounting using the method on commands, the paper contributes to the correct application of this method in practice, specifically in management accounting in companies from the furniture industry. In my opinion the method on commands is an appropriate method for achieving management accounting for companies that have as main activity the production of furniture. When applying the method on commands in cost calculation and in management accounting, the companies must to consider the particularities of the cost calculation, in the furniture industry, like: technical and economic factors from this sector, the technical details of each command, the codification of the commands, planning materials and labor costs for each command, monitoring and recording production costs, registration of the direct costs, distribution of the indirect costs on commands, registration of the indirect costs and registration in management accounting.
Fast neutron fluence calculation benchmark analysis based on 3D MC-SN bidirectional coupling method
International Nuclear Information System (INIS)
The Monte Carlo (MC)-discrete ordinates (SN) bidirectional coupling method is an efficient approach to solve shielding calculation of the large complex nuclear facility. The test calculation was taken by the application of the MC-SN bidirectional coupling method on the shielding calculation of the large PWR nuclear facility. Based on the characteristics of NUREG/CR-6115 PWR benchmark model issued by the NRC, 3D Monte Carlo code was employed to accurately simulate the structure from the core to the thermal shield and the dedicated model of the calculation parts locating in the pressure vessel, while the TORT was used for the calculation from the thermal shield to the second down-comer region. The transform between particle probability distribution of MC and angular flux density of SN was realized by the interface program to achieve the coupling calculation. The calculation results were compared with MCNP and DORT solutions of benchmark report and satisfactory agreements were obtained. The preliminary validity of feasibility by using the method to solve shielding problem of a large complex nuclear device was proved. (authors)
International Nuclear Information System (INIS)
A modified code system based on the point kernel method was developed to use in evaluation of shielding performance for maritime transport of radioactive material. For evaluation of shielding performance accurately in the case of accident, it is required to preciously model the structure of transport casks and shipping vessel, and source term. To achieve accurate modelling of the geometry and source term condition, we aimed to develop the code system by using equivalent information regarding structure and source term used in the Monte Carlo calculation code, MCNP. Therefore, adding an option to use point kernel method to the existing Monte Carlo code, MCNP4C, the code system was developed. To verify the developed code system, dose rate distribution in an exclusive shipping vessel to transport the low level radioactive wastes were calculated by the developed code and the calculated results were compared with measurements and Monte Carlo calculations. It was confirmed that the developed simple calculation method can obtain calculation results very quickly with enough accuracy comparing with the Monte Carlo calculation code MCNP4C
An assessment of methods of calculating sodium voiding reactivity in plutonium fuelled fast reactors
International Nuclear Information System (INIS)
After a survey of the requirements an assessment of the accuracy of calculations of the sodium void effect using UK methods and data is made on the basis of the following work. First, the analysis of small and large sodium voids in the MOZART and Zebra 13 small (300 MW(E)) fast reactor mock-ups and the BIZET large fast reactor mock-ups, all of conventional design. The analysis was carried out using the UK FGL5 fine group nuclear data library, the MURAL cell code, whole reactor diffusion theory calculations of the neutron flux and perturbation theory methods. Exact perturbation theory was used in many cases, otherwise first order perturbation theory calculations were adjusted to give results equivalent to exact perturbation theory. Second, theoretical studies of some effects, including, the effects of extrapolating to fuel operating temperatures, fuel cycle and burn-up effects, and the heterogeneity effects of large fuelled subassemblies in pin geometry. Third, theoretical studies of approximations in the calculational methods including, the importance in the whole reactor calculation of the energy group structure and the spatial mesh, the importance of reactor material boundaries in the calculation of resonance shielding effects, and the use of neutron fluxes calculated using neutron diffusion theory rather than transport theory. (U.K.)
Elastic constants of Al and TiN calculated by ab initio method
Institute of Scientific and Technical Information of China (English)
张铭; 申江; 何家文
2001-01-01
The elastic constants of Al single crystal were calculated by ab initio method for calibration. Three deformation directions were selected in order to obtain the different constants of c11, c12 and c44. The cohesion energy curves of the three deformation directions were calculated. The results of the second order partial differential at the equilibrium point of the cohesion energy curve provide the elastic constants of the Al single crystal. The changes of crystal symmetry and lattice can lead to the deviations of the calculated cohesion energy curves and the accurate elastic constants can not be obtained, but when the correction is taken into calculation, the calculated results are very close to the literature data. It is very difficult to obtain the elastic constants of thin films by experiment and the data from the handbook are scattered in a large scale. However, the elastic constants calculated by this method can be served as a standard. Though the errors of TiN elastic constants calculated by this method are a little higher than that for Al, the results are acceptable.
Zimmermann, Anke; Kuhn, Sandra; Richter, Marten
2016-01-01
Often, the calculation of Coulomb coupling elements for quantum dynamical treatments, e.g., in cluster or correlation expansion schemes, requires the evaluation of a six dimensional spatial integral. Therefore, it represents a significant limiting factor in quantum mechanical calculations. If the size or the complexity of the investigated system increases, many coupling elements need to be determined. The resulting computational constraints require an efficient method for a fast numerical calculation of the Coulomb coupling. We present a computational method to reduce the numerical complexity by decreasing the number of spatial integrals for arbitrary geometries. We use a Green's function formulation of the Coulomb coupling and introduce a generalized scalar potential as solution of a generalized Poisson equation with a generalized charge density as the inhomogeneity. That enables a fast calculation of Coulomb coupling elements and, additionally, a straightforward inclusion of boundary conditions and arbitrarily spatially dependent dielectrics through the Coulomb Green's function. Particularly, if many coupling elements are included, the presented method, which is not restricted to specific symmetries of the model, presents a promising approach for increasing the efficiency of numerical calculations of the Coulomb interaction. To demonstrate the wide range of applications, we calculate internanostructure couplings, such as the Förster coupling, and illustrate the inclusion of symmetry considerations in the method for the Coulomb coupling between bound quantum dot states and unbound continuum states.
Hybrid finite-element/boundary-element method to calculate Oersted fields
International Nuclear Information System (INIS)
The article presents a general-purpose hybrid finite-element/boundary-element method (FEM/BEM) to calculate magnetostatic fields generated by stationary electric currents. The efficiency of this code lies in its ability to simulate Oersted fields in complex geometries with non-uniform current density distributions. As a precursor to the calculation of the Oersted field, an FEM algorithm is employed to calculate the electric current density distribution. The accuracy of the code is confirmed by comparison with analytic results. Two examples show how this method provides important numerical data that can be directly plugged into micromagnetic simulations: The current density distribution in a thin magnetic strip with a notch, and the Oersted field in a three-dimensional contact geometry; similar to the type commonly used in spin-torque driven nano-oscillators. It is argued that a precise calculation of both, the Oersted field and the current density distribution, is essential for a reliable simulation of current-driven micromagnetic processes. - Highlights: • We present a numerical method to calculate Oersted fields for arbitrary geometries. • Description of a FEM algorithm to calculate current density distributions. • It is argued that these methods are valuable for micromagnetic STT-simulations. • Several examples are shown, highlighting the methods’ importance and accuracy
International Nuclear Information System (INIS)
More and more MOX fuels are used in all over the world in the past several decades. Compared with UO2 fuel, it contains some new features. For example, the neutron spectrum is harder and more resonance interference effects within the resonance energy range are introduced because of more resonant nuclides contained in the MOX fuel. In this paper, the wavelets scaling function expansion method is applied to study the resonance behavior of plutonium isotopes within MOX fuel. Wavelets scaling function expansion continuous-energy self-shielding method is developed recently. It has been validated and verified by comparison to Monte Carlo calculations. In this method, the continuous-energy cross-sections are utilized within resonance energy, which means that it's capable to solve problems with serious resonance interference effects without iteration calculations. Therefore, this method adapts to treat the MOX fuel resonance calculation problem natively. Furthermore, plutonium isotopes have fierce oscillations of total cross-section within thermal energy range, especially for 240Pu and 242Pu. To take thermal resonance effect of plutonium isotopes into consideration the wavelet scaling function expansion continuous-energy resonance calculation code WAVERESON is enhanced by applying the free gas scattering kernel to obtain the continuous-energy scattering source within thermal energy range (2.1 eV to 4.0 eV) contrasting against the resonance energy range in which the elastic scattering kernel is utilized. Finally, all of the calculation results of WAVERESON are compared with MCNP calculation. (authors)
The effective atomic numbers of some biomolecules calculated by two methods: A comparative study
DEFF Research Database (Denmark)
Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif
2009-01-01
The effective atomic numbers Z(eff) of some fatty acids and amino acids have been calculated by two numerical methods, a direct method and an interpolation method, in the energy range of 1 keV-20 MeV. The notion of Z(eff) is given a new meaning by using a modern database of photon interaction cross...... constant and equal to the mean atomic number of the material. Wherever possible, the calculated values of Z(eff) are compared with experimental data....
Calculation of U, Ra, Th and K contents in uranium ore by multiple linear regression method
International Nuclear Information System (INIS)
A multiple linear regression method was used to compute γ spectra of uranium ore samples and to calculate contents of U, Ra, Th, and K. In comparison with the inverse matrix method, its advantage is that no standard samples of pure U, Ra, Th and K are needed for obtaining response coefficients
Roundtrip matrix method for calculating the leaky resonant modes of open nanophotonic structures
DEFF Research Database (Denmark)
de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper;
2014-01-01
We present a numerical method for calculating quasi-normal modes of open nanophotonic structures. The method is based on scattering matrices and a unity eigenvalue of the roundtrip matrix of an internal cavity, and we develop it in detail with electromagnetic fields expanded on Bloch modes of...
Polarizable Embedded RI-CC2 Method for Two-Photon Absorption Calculations
DEFF Research Database (Denmark)
Hršak, Dalibor; Khah, Alireza Marefat; Christiansen, Ove;
2015-01-01
We present a novel polarizable embedded resolution-of-identity coupled cluster singles and approximate doubles (PERI-CC2) method for calculation of two-photon absorption (TPA) spectra of large molecular systems. The method was benchmarked for three types of systems: a water-solvated molecule of...
Heat production in growing pigs calculated according to the RQ and CN methods
DEFF Research Database (Denmark)
Christensen, K; Chwalibog, André; Henckel, S;
1988-01-01
1. Heat production, calculated according to the respiratory quotient methods, HE(RQ), and the carbon nitrogen balance method, HE(CN), was compared using the results from a total of 326 balance trials with 56 castrated male pigs fed different dietary composition and variable feed levels during the...
Comparison of Two Methods for Speeding Up Flash Calculations in Compositional Simulations
DEFF Research Database (Denmark)
Belkadi, Abdelkrim; Yan, Wei; Michelsen, Michael Locht;
2011-01-01
Flash calculation is the most time consuming part in compositional reservoir simulations and several approaches have been proposed to speed it up. Two recent approaches proposed in the literature are the shadow region method and the Compositional Space Adaptive Tabulation (CSAT) method. The shado...
Calculation method for the energy loss in the pneumatic mining networks
Petrilean, Dan Codrut; Irimie, Sabin Ioan; Munteanu, Rares
2013-01-01
We popose a calculation method by which we can estimate the value of the loss of pressure along the pipeline, the loss of pressure per length meter of network and the cost of the pneumatic energy loss in the case of the horizontal and vertical pneumatic network. The proposed method is validated by a study case.
DEFF Research Database (Denmark)
Sauer, Stephan P. A.; Pitzner-Frydendahl, Henrik Frank; Buse, Mogens;
2015-01-01
methods, the original SOPPA method as well as SOPPA(CCSD) and RPA(D) in the calculation of vertical electronic excitation energies and oscillator strengths is investigated for a large benchmark set of 28 medium-size molecules with 139 singlet and 71 triplet excited states. The results are compared with...
Methods for calculating CO2 intensity of power generation and consumption: A global perspective
Graus, W.H.J.; Worrell, E.
2011-01-01
This paper compares five methods to calculate CO2 intensity (g/kWh) of power generation, based on different ways to take into account combined heat and power generation. It was found that the method chosen can have a large impact on the CO2 intensity for countries with relatively large amounts of co
A Method of Calculating Motion Error in a Linear Motion Bearing Stage
Directory of Open Access Journals (Sweden)
Gyungho Khim
2015-01-01
Full Text Available We report a method of calculating the motion error of a linear motion bearing stage. The transfer function method, which exploits reaction forces of individual bearings, is effective for estimating motion errors; however, it requires the rail-form errors. This is not suitable for a linear motion bearing stage because obtaining the rail-form errors is not straightforward. In the method described here, we use the straightness errors of a bearing block to calculate the reaction forces on the bearing block. The reaction forces were compared with those of the transfer function method. Parallelism errors between two rails were considered, and the motion errors of the linear motion bearing stage were measured and compared with the results of the calculations, revealing good agreement.
Precise integration method without inverse matrix calculation for structural dynamic equations
Institute of Scientific and Technical Information of China (English)
Wang Mengfu; F. T. K. Au
2007-01-01
The precise integration method proposed for linear time-invariant homogeneous dynamic systems can provide accurate numerical results that approach an exact solution at integration points. However, difficulties arise when the algorithm is used for non-homogeneous dynamic systems due to the inverse matrix calculation required. In this paper, the structural dynamic equalibrium equations are converted into a special form, the inverse matrix calculation is replaced by the Crout decomposition method to solve the dynamic equilibrium equations, and the precise integration method without the inverse matrix calculation is obtained. The new algorithm enhances the present precise integration method by improving both the computational accuracy and efficiency. Two numerical examples are given to demonstrate the validity and efficiency of the proposed algorithm.
Calculation method of load distribution on pipe threaded connections under tension load
Chen, Shoujun; Gao, Lianxin; An, Qi
2011-06-01
This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.
Method of tallying adjoint fluence and calculating kinetics parameters in Monte Carlo codes
International Nuclear Information System (INIS)
A method of using iterated fission probability to estimate the adjoint fluence during particles simulation, and using it as the weighting function to calculate kinetics parameters βeff and A in Monte Carlo codes, was introduced in this paper. Implements of this method in continuous energy Monte Carlo code MCNP and multi-group Monte Carlo code MCMG are both elaborated. Verification results show that, with regardless additional computing cost, using this method, the adjoint fluence accounted by MCMG matches well with the result computed by ANISN, and the kinetics parameters calculated by MCNP agree very well with benchmarks. This method is proved to be reliable, and the function of calculating kinetics parameters in Monte Carlo codes is carried out effectively, which could be the basement for Monte Carlo codes' utility in the analysis of nuclear reactors' transient behavior. (authors)
International Nuclear Information System (INIS)
The Hanford Dose Overview Program is a Hanford site-wide service established to provide a method of assuring the consistency of Hanford-related environmental dose assessments. This document serves as a guide to the Hanford contractors for obtaining or performing Hanford-related environmental dose calculations. The program serves as a focal point for Hanford environmental dose calculation activities and provides a number of services for Hanford contractors involved in calculation of environmental doses. Site specific input data and assumptions have been compiled and are maintained for use by the contractors in calculating Hanford environmental doses. The data and assumptions, to the extent they apply, should be used in Hanford calculations. These data are not all inclusive and will be modified should additional or more appropriate information become available
Guideline of Monte Carlo calculation. Neutron/gamma ray transport simulation by Monte Carlo method
2002-01-01
This report condenses basic theories and advanced applications of neutron/gamma ray transport calculations in many fields of nuclear energy research. Chapters 1 through 5 treat historical progress of Monte Carlo methods, general issues of variance reduction technique, cross section libraries used in continuous energy Monte Carlo codes. In chapter 6, the following issues are discussed: fusion benchmark experiments, design of ITER, experiment analyses of fast critical assembly, core analyses of JMTR, simulation of pulsed neutron experiment, core analyses of HTTR, duct streaming calculations, bulk shielding calculations, neutron/gamma ray transport calculations of the Hiroshima atomic bomb. Chapters 8 and 9 treat function enhancements of MCNP and MVP codes, and a parallel processing of Monte Carlo calculation, respectively. An important references are attached at the end of this report.
Shielding calculations for the Gothenburg Pulsed Neutron Generator by the discrete ordinates method
International Nuclear Information System (INIS)
The discrete ordinates method has been used to calculate a proper shield to be placed around the target of the Gothenburg Pulsed Neutron Generator (PUNGGO) to minimize the dose rate outside the laboratory building. Simple calculations for slab of different materials were performed to study the effectiveness of different shielding materials. Final calculations were performed for a spherical geometry approximating the whole experimental hall to include the effect of neutron scattering from the walls and from the air. An ANISN code with a 22-group coupled neutron-gamma cross section library has been used throughout this work. The adequacy of the ANISN code for dose rate calculation has also been tested through some simple benchmark calculations. (Auth.)
Rodný, Marek; Nolz, Reinhard; Novák, Viliam; Hlaváčiková, Hana; Loiskandl, Willibald; Himmelbauer, Margarita
2016-04-01
The aim of this study was to present and validate an alternative evapotranspiration calculation procedure that includes specific expression for the aerodynamic resistance. Calculated daily potential evapotranspiration totals were compared to the results of FAO56 procedure application and to the results of measurements taken with a precision weighing lysimeter permanently grown with irrigated, short grass. For the examination period from March 17 through October 31, 2011, it was found that daily potential evapotranspiration estimates obtained by both calculation procedures fitted well to the lysimeter measurements. Potential evapotranspiration daily totals calculated with the use of the proposed aerodynamic resistance calculation procedure gave better results for days with higher evapotranspiration, compared to the FAO56 method. The most important is that the approach based on the proposed alternative aerodynamic resistance could be effectively used even for a wide variety of crops, because it is not limited to any particular crop.
Ding, E. J.
2015-06-01
The time-independent lattice Boltzmann algorithm (TILBA) is developed to calculate the hydrodynamic interactions between two particles in a Stokes flow. The TILBA is distinguished from the traditional lattice Boltzmann method in that a background matrix (BGM) is generated prior to the calculation. The BGM, once prepared, can be reused for calculations for different scenarios, and the computational cost for each such calculation will be significantly reduced. The advantage of the TILBA is that it is easy to code and can be applied to any particle shape without complicated implementation, and the computational cost is independent of the shape of the particle. The TILBA is validated and shown to be accurate by comparing calculation results obtained from the TILBA to analytical or numerical solutions for certain problems.
Electromagnetically induced nuclear beta decay calculated by a Green's function method
International Nuclear Information System (INIS)
The transition probability for enhancement of forbidden nuclear beta decay by an applied plane-wave electromagnetic field is calculated in a nonrelativistic spinless approximation by a Green's function method. The calculation involves a stationary-phase approximation. The stationary phase points in the presence of an intense field are located in very different positions than they are in the field-free case. In order-of-magnitude terms, the results are completely consistent with an earlier, much more complete wave-function calculation which includes spin and relativistic effects. Both the present Green's function calculation and the earlier wave function calculation give electromagnetic contributions in first-forbidden nuclear beta decay matrix elements which are of order (R0/lambda-dash-bar/sub C/)2 with respect to allowed decays, where R0 is the nuclear radius and lambda-dash-bar/sub C/ is the electron Compton wavelength
International Nuclear Information System (INIS)
The problem of calculating the frequency difference caused by a perturbing spheroidal-shaped body in the quasistatic field of an arbitrary configuration is being considered when studying the RF cavity parameter with the small perturbation method. The calculations are made with an account of the perturbing body formfactor only for the electrostatic component of the field taken in the electrostatic approximation. The general calculation technique, some formulas and approximated calculational algorithms for a number of particular cases are given. For a more complicated case, i.e., an accelerator with spatial periodic RF quadrupole focusing, the results obtained with the general methods are compared with those obtained experimentally for a body of the metalic ball shape. The technique is assigned for precise tuning of the fields in linear resonance ion accelerators. 15 refs.; 8 figs
An improved method for calculating force distributions in moment-stiff timber connections
DEFF Research Database (Denmark)
Ormarsson, Sigurdur; Blond, Mette
2012-01-01
An improved method for calculating force distributions in moment-stiff metal dowel-type timber connections is presented, a method based on use of three-dimensional finite element simulations of timber connections subjected to moment action. The study that was carried out aimed at determining how...... the slip modulus varies with the angle between the direction of the dowel forces and the fibres in question, as well as how the orthotropic stiffness behaviour of the wood material affects the direction and the size of the forces. It was assumed that the force distribution generated by the moment...... action taking place strives to minimize the slip rotation between the separate members of a given timber connection. The results of modified hand calculations based on the finite element calculations carried out were found to differ appreciably from the results of conventional hand calculations....
International Nuclear Information System (INIS)
The equivalence theorem providing a relation between a homogeneous and a heterogeneous medium has been used in the resonance calculation for the heterogeneous system. The accuracy of the resonance calculation based on the equivalence theorem depends on how accurately the fuel collision probability is expressed by the rational terms. The fuel collision probability is related to the Dancoff factor in closely packed lattices. The calculation of the Dancoff factor is one of the most difficult problems in the core analysis because the actual configuration of fuel elements in the lattice is very complex. Most reactor physics codes currently used are based on the roughly calculated black Dancoff factor, where total cross section of the fuel is assumed to be infinite. Even the black Dancoff factors have not been calculated accurately though many methods have been proposed. The equivalence theorem based on the black Dancoff factor causes some errors inevitably due to the approximations involved in the Dancoff factor calculation and the derivation of the fuel collision probability, but they have not been evaluated seriously before. In this study, a Monte Carlo program - G-DANCOFF - was developed to calculate not only the traditional black Dancoff factor but also grey Dancoff factor where the medium is described realistically. G-DANCOFF calculates the Dancoff factor based on its collision probability definition in an arbitrary arrangement of cylindrical fuel pins in full three-dimensional fashion. G-DANCOFF was verified by comparing the black Dancoff factors calculated for the geometries where accurate solutions are available. With 100,000 neutron histories, the calculated results by G-DANCOFF were matched within maximum 1% and in most cases less than 0.2% with previous results. G-DANCOFF also provides graphical information on particle tracks which makes it possible to calculate the Dancoff factor independently. The effects of the Dancoff factor on the criticality calculation
International Nuclear Information System (INIS)
In this paper we present a primitive variable Newton-based solution method with a block-line linear equation solver for the calculation of reacting flows. The present approach is compared with the stream function-vorticity Newton's method and the SIMPLER algorithm on the calculation of a system of fully elliptic equations governing an axisymmetric methane-air laminar diffusion flame. The chemical reaction is modeled by the flame sheet approximation. The numerical solution agrees well with experimental data in the major chemical species. The comparison of three sets of numerical results indicates that the stream function-vorticity solution using the approximate boundary conditions reported in the previous calculations predicts a longer flame length and a broader flame shape. With a new set of modified vorticity boundary conditions, we obtain agreement between the primitive variable and stream function-vorticity solutions. The primitive variable Newton's method converges much faster than the other two methods. Because of much less computer memory required for the block-line tridiagonal solver compared to a direct solver, the present approach makes it possible to calculate multidimensional flames with detailed reaction mechanisms. The SIMPLER algorithm shows a slow convergence rate compared to the other two methods in the present calculation
Formula calculation methods of water content in sweet natural gas and their adaptability analysis
Directory of Open Access Journals (Sweden)
Zhu Lin
2014-12-01
Full Text Available Estimation of water content is the foundation of natural gas processing and designing, and a formula calculation method provides a solution simple and easy to be programmed by computers. In this regard, several main formula calculation methods of water content in sweet natural gas were reviewed and evaluated individually. There are formulas fitted with nomographic data (e.g. Sloan formula, Ning Yingnan formula, Khaled formula and Bahadori formula, empirical formulas fitted with experimental data (e.g. Zhu Lin formula, Behr formula and Kazim formula and formulas generated based on water-hydrocarbon phases equilibrium (e.g. Saturated Vapor Pressure Model, Modified Ideal Model, Simplified Thermodynamic Model and Bukacek formula. The comparison of calculated and experimental values of each above formula calculation method indicates that, the Khaled formula provided the minimum average absolute deviation (AAD – 2.524 0%, while the Behr method achieved the maximum AAD – 19.255%. After the analysis of the AAD results calculated by the methods at different temperature ranges, the Zhu Lin formula is recommended for −50 to −40 °C, the Sloan formula for −40 to 0 °C, the Simplified Thermodynamic Model for 0 to 37.78 °C, the Khaled formula for 37.78 to 171.11 °C, and the Bukacek formula for 171.11 to 237.78 °C.
Moore, Stan G; Crozier, Paul S
2014-06-21
Several extensions and improvements have been made to the multilevel summation method (MSM) of computing long-range electrostatic interactions. These include pressure calculation, an improved error estimator, faster direct part calculation, extension to non-orthogonal (triclinic) systems, and parallelization using the domain decomposition method. MSM also allows fully non-periodic long-range electrostatics calculations which are not possible using traditional Ewald-based methods. In spite of these significant improvements to the MSM algorithm, the particle-particle particle-mesh (PPPM) method was still found to be faster for the periodic systems we tested on a single processor. However, the fast Fourier transforms (FFTs) that PPPM relies on represent a major scaling bottleneck for the method when running on many cores (because the many-to-many communication pattern of the FFT becomes expensive) and MSM scales better than PPPM when using a large core count for two test problems on Sandia's Redsky machine. This FFT bottleneck can be reduced by running PPPM on only a subset of the total processors. MSM is most competitive for relatively low accuracy calculations. On Sandia's Chama machine, however, PPPM is found to scale better than MSM for all core counts that we tested. These results suggest that PPPM is usually more efficient than MSM for typical problems running on current high performance computers. However, further improvements to MSM algorithm could increase its competitiveness for calculation of long-range electrostatic interactions. PMID:24952528
Progress on burnup calculation methods coupling Monte Carlo and depletion codes
Energy Technology Data Exchange (ETDEWEB)
Leszczynski, Francisco [Comision Nacional de Energia Atomica, San Carlos de Bariloche, RN (Argentina). Centro Atomico Bariloche]. E-mail: lesinki@cab.cnea.gob.ar
2005-07-01
Several methods of burnup calculations coupling Monte Carlo and depletion codes that were investigated and applied for the author last years are described. here. Some benchmark results and future possibilities are analyzed also. The methods are: depletion calculations at cell level with WIMS or other cell codes, and use of the resulting concentrations of fission products, poisons and actinides on Monte Carlo calculation for fixed burnup distributions obtained from diffusion codes; same as the first but using a method o coupling Monte Carlo (MCNP) and a depletion code (ORIGEN) at a cell level for obtaining the concentrations of nuclides, to be used on full reactor calculation with Monte Carlo code; and full calculation of the system with Monte Carlo and depletion codes, on several steps. All these methods were used for different problems for research reactors and some comparisons with experimental results of regular lattices were performed. On this work, a resume of all these works is presented and discussion of advantages and problems found are included. Also, a brief description of the methods adopted and MCQ system for coupling MCNP and ORIGEN codes is included. (author)
Methods and programs of thermal hydraulic calculations of fast reactor fuel assemblies
International Nuclear Information System (INIS)
The methods and computer codes for calculating the velocity and temperature distributions in fast reactor fuel assemblies are described and analyzed. Three levels of thermal hydraulic analysis of fuel element bundles can be distinguished, viz.: analysis of local characteristics (finite element method, finite difference method), subchannel analysis (lumped parameter method), and analysis of characteristics averaged over volumes (porous body model). The possibilities of the existing computer codes and methods are demonstrated and conclusions regarding the future development of methods of and codes for thermal hydraulic analysis of fuel assemblies are presented. (author). 102 figs., 17 tabs., 256 refs
Meng, Qing-Xin; Pan, He-Ping; Luo, Miao
2015-12-01
We conducted a study on the numerical calculation and response analysis of a transient electromagnetic field generated by a ground source in geological media. One solution method, the traditional discrete image method, involves complex operation, and its digital filtering algorithm requires a large number of calculations. To solve these problems, we proposed an improved discrete image method, where the following are realized: the real number of the electromagnetic field solution based on the Gaver-Stehfest algorithm for approximate inversion, the exponential approximation of the objective kernel function using the Prony method, the transient electromagnetic field according to discrete image theory, and closed-form solution of the approximate coefficients. To verify the method, we tentatively calculated the transient electromagnetic field in a homogeneous model and compared it with the results obtained from the Hankel transform digital filtering method. The results show that the method has considerable accuracy and good applicability. We then used this method to calculate the transient electromagnetic field generated by a ground magnetic dipole source in a typical geoelectric model and analyzed the horizontal component response of the induced magnetic field obtained from the "ground excitation-stratum measurement" method. We reached the conclusion that the horizontal component response of a transient field is related to the geoelectric structure, observation time, spatial location, and others. The horizontal component response of the induced magnetic field reflects the eddy current field distribution and its vertical gradient variation. During the detection of abnormal objects, positions with a zero or comparatively large offset were selected for the drillhole measurements or a comparatively long observation delay was adopted to reduce the influence of the ambient field on the survey results. The discrete image method and forward calculation results in this paper
3-D Whole-Core Transport Calculation with 3D/2D Rotational Plane Slicing Method
International Nuclear Information System (INIS)
Use of the method of characteristics (MOC) is very popular due to its capability of heterogeneous geometry treatment and widely used for 2-D core calculation, but direct extension of MOC to 3-D core is not so attractive due to huge calculational cost. 2-D/1-D fusion method was very successful for 3-D calculation of current generation reactor types (highly heterogeneous in radial direction but piece-wise homogeneous in axial direction). In this paper, 2-D MOC concept is extended to 3-D core calculation with little modification of an existing 2-D MOC code. The key idea is to suppose 3-D geometry as a set of many 2-D planes like a phone-directory book. Dividing 3-D structure into a large number of 2-D planes and solving each plane with a simple 2-D SN transport method would give the solution of a 3-D structure. This method was developed independently at KAIST but it is found that this concept is similar with that of 'plane tracing' in the MCCG-3D code. The method developed was tested on the 3-D C5G7 OECD/NEA benchmark problem and compared with the 2-D/1-D fusion method. Results show that the proposed method is worth investigating further. A new approach to 3-D whole-core transport calculation is described and tested. By slicing 3-D structure along characteristic planes and solving each 2-D plane problem, we can get 3-D solution. The numerical test results indicate that the new method is comparable with the 2D/1D fusion method and outperforms other existing methods. But more fair comparison should be done in similar discretization level
Improved Method of Generating Bit Reserved Numbers for Calculating Fast Fourier Transform
Directory of Open Access Journals (Sweden)
T. Suresh
1996-10-01
Full Text Available Fast Fourier Transform (FFT is an important tool required for signal processing in defence applications. This paper reports an improved method for generating bit reversed numbers needed in calculating FFT using radix-2. The refined algorithm takes advantage of some features of the bit reversed numbers, using intermediate array for storage and improved procedure for calculating base values required when generating bit reversed numbers.
Method of heating regime change calculation due to the pollution of TPP surface condensers
International Nuclear Information System (INIS)
A method for defining the heating regime change of TPP condensers due to the scale formation on cooling its surfaces is proposed. The cooling water velocity change and its influence on condensers heat transfer coefficient is calculated. The calculation of the K-200-130 TPP condenser is realized. As a result of it the change of electric power due to the thickness of scale formation and the primary temperature of cooling water is determined
A simple method for evaluation of uncertainties in fission product decay heat summation calculations
International Nuclear Information System (INIS)
The present precision of nuclear data for the aggregate decay heat evaluation is analyzed quantitatively for 50 fissioning systems. In the practical calculation, a simple approximate method is proposed in order to avoid complication of the calculation and to point out easily the main causal nuclei of the uncertainties in decay heat calculations. As for the independent yield, the correlation among the values is taken into account. For this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library. (author)
Methods for calculating phase angle from measured whole body bioimpedance modulus
Nordbotten, Bernt J.; Martinsen, Ørjan G.; Grimnes, Sverre
2010-04-01
Assuming the Cole equation we have developed a method to calculate the Cole parameters (R0, R∞, α, τZ) and the phase angle from four frequency measurements of impedance modulus values. The values obtained compare well with impedance measurements obtained using the Solatron 1294/1260 as obtained when making whole body measurements on five persons. We have also performed calculations using an algorithm based on the Kramers-Kronig approach. The results which are presented show that it is possible to obtain complete body impedance data combining relatively simple measurements with advanced calculation using a laptop. This extends the potential of portable equipment, since the measurements will require less instrumentation.
Institute of Scientific and Technical Information of China (English)
CHEN Yan; TANG Weilin; FAN Wei; FAN Jun
2012-01-01
A geometrical acoustic method based on image-source method and physicM acoustic method was developed to calculate the echo of targets submerged in the shallow water waveguide. The incident rays and the scattering rays are reflected by two boundaries for many times, and then the back rays become countless. The total backscattering field is obtained through summing up the scattering field produced by each combination of incident rays and back rays. The echo of the 10m-radius pressure release sphere in Pekeris waveguide with the range is calculated by the geometrical acoustic method. Compared with the results calculated by the wave acoustic method in the available literature, it shows that both are in accordance on average value and descend trend. The following results indicate that the difference between Effective Target Strength （ETS） in shallow water and the Target Strength （TS） in free space for spheres and certain other rounded objects is small. However, the ETS of some targets such as cone-shaped is quite different from TS in free space, which can lead to large errors in estimating a target＇s scattering property using traditional sonar equation. Compared with the method of wave acoustics, the geometrical acoustic method not only has the definite physical meaning but also can calculate the echo of complex objects in shallow water waveguide.
On the application of Runge-Kutta methods to transport calculations
International Nuclear Information System (INIS)
Under a definition suitable to the transport equation, it is shown that the (two-stage explicit) Runge-Kutta (RK) methods having order at least two, and requiring essentially only one source evaluation per cell, consist of a one-parameter family, plus two additional methods. Two of these, the midpoint corrector and improved Euler methods, are selected for detailed computational comparison with the classical diamond-difference and step-characteristic methods. Extensive monodirectional calculations reveal that the RK methods display A-instability for cell pathlengths exceeding two mean free paths, but that they are nearly competitive with the classical methods for small cell widths. It is shown how the two subject RK methods can be augmented by closure approximations, so as to permit their use in source iteration for multiple direction calculations. The results of such calculations show that: for small cell widths, the RK methods again are nearly competitive as regards accuracy, although the A-stability requirement can impose a stringent upper bound on the acceptable cell widths; the RK methods interact well with source iteration, even though they do not conserve particles; the particular closure approximations selected retain the second-order accuracy of the basic underlying methods
On the application of runge-kutta methods to transport calculations
International Nuclear Information System (INIS)
Under a definition suitable to the transport equation, it is shown that the (two-stage explicit) Runge-Kutta (RK) methods having order of at least 2, and requiring essentially only one source evaluation per cell, consist of a one-parameter family, plus two additional methods. Two of these, the midpoint corrector and improved Euler methods, are selected for detailed computational comparison with the classical diamond-difference and step characteristic methods. Extensive monodirectional calculations reveal that the RK methods display absolute instability for cell path lengths exceeding 2 mfp, but that they are nearly competitive with the classical methods for small cell widths. It is shown how the two subject RK methods can be augmented by closure approximations, so as to permit their use in source iteration for multiple-direction calculations. The results of such calculations show that for small cell widths, the RK methods again are nearly competitive in accuracy, although the absolute stability requirement can impose a stringent upper bound on the acceptable cell widths; the RK methods interact well with source iteration, even though they do not conserve particles; and the particular closure approximations selected retain the second-order accuracy of the basic underlying methods
Introducing and validating a new method for coupling neutronic and thermal-hydraulic calculations
Energy Technology Data Exchange (ETDEWEB)
Zare, Nafiseh [Department of Nuclear Engineering, Faculty of Engineering, Azad Islamic University, Science and Research- Branch, Punak Square, Tehran (Iran, Islamic Republic of); Fadaei, Amir Hosein, E-mail: Fadaei_amir@aut.ac.i [Faculty of Nuclear Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnique), Hafez Street, Tehran (Iran, Islamic Republic of); Rahgoshay, Mohammad [Department of Nuclear Engineering, Faculty of Engineering, Azad Islamic University, Science and Research- Branch, Punak Square, Tehran (Iran, Islamic Republic of); Fadaei, Mohammad Mehdi [Department of Electrical Engineering, Faculty of Engineering, Central Tehran Branch, Islamic Azad University, Punak Square, Tehran (Iran, Islamic Republic of); Kia, Shabnam [Department of Nuclear Engineering, Faculty of Engineering, Azad Islamic University, Science and Research- Branch, Punak Square, Tehran (Iran, Islamic Republic of)
2010-11-15
Research highlights: {yields} Reactor behavior affects from reciprocal effects between neutronic and thermo-hydraulic. {yields} Reliable reactor analysis requires coupling of neutronic and thermal-hydraulic calculation. {yields} Iterative process can be used to perform neutronic and thermal-hydraulic calculation. - Abstract: In this study, a new and innovative method is introduced for analyzing neutronic and thermal-hydraulic calculation. For this aim, VVR-S research reactor was selected, and the calculation procedure was performed for it. WIMS, CITATION and COBRA-EN codes were used for investigation. Calculation model consists of two sub-models: neutronic and thermo-hydraulic. The neutronic model uses WIMS and CITATION codes for neutronic simulation of the reactor core and calculating flux and power distribution over it. WIMS code simulates the fuel assemblies and CITATION models the core. The thermal-hydraulic model uses COBRA-EN code for performing the relative calculation. In this study, FORTRAN 90 program is used for linking two sub-models and performing the calculation. The proposed procedure is performed for VVR-S analysis and finally, the obtained results are compared with the experimental results that show good agreement with it.
Introducing and validating a new method for coupling neutronic and thermal-hydraulic calculations
International Nuclear Information System (INIS)
Research highlights: → Reactor behavior affects from reciprocal effects between neutronic and thermo-hydraulic. → Reliable reactor analysis requires coupling of neutronic and thermal-hydraulic calculation. → Iterative process can be used to perform neutronic and thermal-hydraulic calculation. - Abstract: In this study, a new and innovative method is introduced for analyzing neutronic and thermal-hydraulic calculation. For this aim, VVR-S research reactor was selected, and the calculation procedure was performed for it. WIMS, CITATION and COBRA-EN codes were used for investigation. Calculation model consists of two sub-models: neutronic and thermo-hydraulic. The neutronic model uses WIMS and CITATION codes for neutronic simulation of the reactor core and calculating flux and power distribution over it. WIMS code simulates the fuel assemblies and CITATION models the core. The thermal-hydraulic model uses COBRA-EN code for performing the relative calculation. In this study, FORTRAN 90 program is used for linking two sub-models and performing the calculation. The proposed procedure is performed for VVR-S analysis and finally, the obtained results are compared with the experimental results that show good agreement with it.
International Nuclear Information System (INIS)
Development of the SUHAM-U code for burnup calculations of VVER-1000 fuel assemblies with uranium and MOX fuel is described. Developed SUHAM-U code has capacity to calculate burnup in each fuel or poison zone of each cell of VVER-1000 fuel assembly. In so doing Surface Harmonics Method is used for calculation of the detail neutron spectra in fuel assembly at separated burnup values. Verification of SUHAM-U code by burnup calculations of VVER-1000 fuel assemblies with uranium and MOX fuel has been carried out. Comparisons were carried out with calculations by UNK and RECOL codes. UNK code uses the first collisions probabilities method for solution of the neutron transport equation and RECOL code uses Monte-Carlo method with point-wise continues energy presentation of cross-sections. The main conclusion of all comparisons is the SUHAM-U code calculates the fuel burnup of VVER-1000 fuel assemblies with uranium and MOX fuel with enough high accuracy. Time expenditures are adduced. (authors)
Energy Technology Data Exchange (ETDEWEB)
Boyarinov, V. F.; Davidenko, V. D.; Polismakov, A. A.; Tsibulsky, V. F. [Russian Research Center Kurchatov Inst., Nuclear Reactor Inst., 123182, Moscow (Russian Federation)
2006-07-01
Development of the SUHAM-U code for burnup calculations of VVER-1000 fuel assemblies with uranium and MOX fuel is described. Developed SUHAM-U code has capacity to calculate burnup in each fuel or poison zone of each cell of VVER-1000 fuel assembly. In so doing Surface Harmonics Method is used for calculation of the detail neutron spectra in fuel assembly at separated burnup values. Verification of SUHAM-U code by burnup calculations of VVER-1000 fuel assemblies with uranium and MOX fuel has been carried out. Comparisons were carried out with calculations by UNK and RECOL codes. UNK code uses the first collisions probabilities method for solution of the neutron transport equation and RECOL code uses Monte-Carlo method with point-wise continues energy presentation of cross-sections. The main conclusion of all comparisons is the SUHAM-U code calculates the fuel burnup of VVER-1000 fuel assemblies with uranium and MOX fuel with enough high accuracy. Time expenditures are adduced. (authors)
Stabilizing Canonical-Ensemble Calculations in the Auxiliary-Field Monte Carlo Method
Gilbreth, C N
2014-01-01
Quantum Monte Carlo methods are powerful techniques for studying strongly interacting Fermi systems. However, implementing these methods on computers with finite-precision arithmetic requires careful attention to numerical stability. In the auxiliary-field Monte Carlo (AFMC) method, low-temperature or large-model-space calculations require numerically stabilized matrix multiplication. When adapting methods used in the grand-canonical ensemble to the canonical ensemble of fixed particle number, the numerical stabilization increases the number of required floating-point operations for computing observables by a factor of the size of the single-particle model space, and thus can greatly limit the systems that can be studied. We describe an improved method for stabilizing canonical-ensemble calculations in AFMC that exhibits better scaling, and present numerical tests that demonstrate the accuracy and improved performance of the method.
Realistic methods for calculating the releases and consequences of a large LOCA
International Nuclear Information System (INIS)
This report describes a calculational route to predict realistic radiological consequences for a successfully terminated large-loss-of-coolant accident (LOCA) at a pressurized-water reactor (PWR). All steps in the calculational route are considered. For each one, a brief comment is made on the significant differences between the methods of calculation that were identified in the benchmark studies and recommendations are made for the methods and data for carrying out realistic calculations. These are based on the best supportable methods and data and the technical basis for each recommendation is given. Where the lack of well-validated methods or data means that the most realistic method that can be justified is considered to be very conservative, the need for further research is identified. The behaviour of inorganic iodine and the removal of aerosols from the atmosphere of the reactor building are identified as areas of particular importance. Where the retention of radioactivity is sensitive to design features, these are identified and, for the most importance features, the impact of different designs on the release of activity is indicated. The predictions of the proposed model are calculated for each stage and compared with the releases of activity predicted by the licensing methods that were used in the earlier benchmark studies. The conservative nature of the latter is confirmed. Methods and data are also presented for calculating the resulting doses to members of the public of the National Radiological Protection Boards as a result of work carried out by several national bodies in the UK. Other, equally acceptable, models are used in other countries of the Community and some examples are given
Calculation of the one-dimension two energy groups lambda modes, using the boundary functions method
International Nuclear Information System (INIS)
Using parameters and cross sections of SIMULATE-III code, a method to obtain the lambda modes was developed. In order to validate the method, eigenvalues and eigenfunctions obtained with this method were compared with those obtained using SIMULATE III and VENTURE codes. For superior order modes, the results were compared with those calculated by General Electric, for the Cofrentes Nuclear Power Plant-Spain. (author)
Exploration of Local Force Calculations Using the Methods of Regularized Stokeslets
Thompson, Terese
2015-01-01
We analyze the performance of the Method of Regularized Stokeslets (MRS) and the Method of Auxiliary Regularized Stokeslets (MARS) in computing the forces necessary to translate a sphere with unit velocity in Stokes ﬂow. In particular, we explore the dependence of local and global force calculations on various parameters associated with each method. The parameters we varied include the regularization parameter, the discretization of the sphere, and the spread and placement of the auxiliary St...
Fast nodal core-wise green's function method for neutron diffusion calculations
International Nuclear Information System (INIS)
A fast nodal core-wise Green's function method for neutron diffusion calculations was developed. A new idea of building core-wise Green's function library was proposed, and the computer code CGFM was encoded. It was qualified by some benchmark problems and the Qinshan Nuclear Power Plant problem. The numerical results demonstrated that this method is 10 times faster than nodal Green's function method (NGFM) with idea precision
An energy transfer method for 4D Monte Carlo dose calculation
Siebers, Jeffrey V; Zhong, Hualiang
2008-01-01
This article presents a new method for four-dimensional Monte Carlo dose calculations which properly addresses dose mapping for deforming anatomy. The method, called the energy transfer method (ETM), separates the particle transport and particle scoring geometries: Particle transport takes place in the typical rectilinear coordinate system of the source image, while energy deposition scoring takes place in a desired reference image via use of deformable image registration. Dose is the energy ...
A superposition method to calculate the interaction effect between bodies in diffusion theory
International Nuclear Information System (INIS)
We introduce a method for calculating the neutron flux around a finite number of spheres arranged in-line. The method uses the concept of superposition in which the solution for a group of spheres is composed of a sum of solutions for the individual spheres. We illustrate the method by a simple example based on a chain of highly absorbing spheres in a non-absorbing moderator and show that it converges rapidly to the exact solution
Unfolding method for the first-principles LCAO electronic structure calculations
Lee, Chi-Cheng; Yamada-Takamura, Yukiko; Ozaki, Taisuke
2012-01-01
Unfolding the band structure of a supercell to a normal cell enables us to investigate how symmetry breakers such as surfaces and impurities perturb the band structure of the normal cell. We generalize the unfolding method, originally developed based on Wannier functions, to the linear combination of atomic orbitals (LCAO) method, and present a general formula to calculate the unfolded spectral weight. The LCAO basis set is ideal for the unfolding method because of the invariance that basis f...
A fast high-order method to calculate wakefield forces in an electron beam
Energy Technology Data Exchange (ETDEWEB)
Qiang, Ji; Mitchell, Chad; Ryne, Robert D.
2012-03-22
In this paper we report on a high-order fast method to numerically calculate wakefield forces in an electron beam given a wake function model. This method is based on a Newton-Cotes quadrature rule for integral approximation and an FFT method for discrete summation that results in an O(Nlog(N)) computational cost, where N is the number of grid points. Using the Simpson quadrature rule with an accuracy of O(h4), where h is the grid size, we present numerical calculation of the wakefields from a resonator wake function model and from a one-dimensional coherent synchrotron radiation (CSR) wake model. Besides the fast speed and high numerical accuracy, the calculation using the direct line density instead of the first derivative of the line density avoids numerical filtering of the electron density function for computing the CSR wakefield force. I. INTRODUCTION
A fast high-order method to calculate wakefields in an electron beam
Qiang, Ji; Mitchell, Chad; Ryne, Robert D.
2012-08-01
In this paper, we report on a high-order fast method to numerically calculate wakefields in an electron beam given a wake function model. This method is based on a Newton-Cotes quadrature rule for integral approximation and an FFT method for discrete summation that results in an O(N log(N)) computational cost, where N is the number of grid points. Using the Simpson quadrature rule with an accuracy of O(h4), where h is the grid size, we present numerical calculation of the wakefields from a resonator wake function model and from a one-dimensional coherent synchrotron radiation (CSR) wake model. Besides the fast speed and high numerical accuracy, the calculation using the direct line density instead of the first derivative of the line density avoids numerical filtering of the electron density function for computing the CSR wakefield.
Calculation methods for single-sided natural ventilation - simplified or detailed?
DEFF Research Database (Denmark)
Larsen, Tine Steen; Plesner, Christoffer; Leprince, Valérie
2016-01-01
) airflow. The predicted airflow rate from the new and three existing design expressions are compared to full-scale wind tunnel measurements. The new proposed calculation method for single-sided ventilation shows results, limiting the overestimation of air flow rates at especially low driving pressures...... handled. This paper presents a newly developed simplified calculation method for single-sided natural ventilation, which is proposed for the revised standard FprEN 16798-7 (earlier EN 15242:2007) for design of ventilative cooling. The aim for predicting ventilative cooling is to find the most suitable......, while maintaining an acceptable correlation with measurements on average and the authors consider the simplified calculation method well suited for the use in standards such as FprEN 16798-7 for the ventilative cooling effects from single-sided natural ventilation The comparison of different design...
A fast high-order method to calculate wakefields in an electron beam
International Nuclear Information System (INIS)
In this paper, we report on a high-order fast method to numerically calculate wakefields in an electron beam given a wake function model. This method is based on a Newton–Cotes quadrature rule for integral approximation and an FFT method for discrete summation that results in an O(Nlog(N)) computational cost, where N is the number of grid points. Using the Simpson quadrature rule with an accuracy of O(h4), where h is the grid size, we present numerical calculation of the wakefields from a resonator wake function model and from a one-dimensional coherent synchrotron radiation (CSR) wake model. Besides the fast speed and high numerical accuracy, the calculation using the direct line density instead of the first derivative of the line density avoids numerical filtering of the electron density function for computing the CSR wakefield.
A fast high-order method to calculate wakefield forces in an electron beam
Qiang, Ji; Ryne, Robert D
2012-01-01
In this paper we report on a high-order fast method to numerically calculate wakefield forces in an electron beam given a wake function model. This method is based on a Newton-Cotes quadrature rule for integral approximation and an FFT method for discrete summation that results in an $O(Nlog(N))$ computational cost, where $N$ is the number of grid points. Using the Simpson quadrature rule with an accuracy of $O(h^4)$, where $h$ is the grid size, we present numerical calculation of the wakefields from a resonator wake function model and from a one-dimensional coherent synchrotron radiation (CSR) wake model. Besides the fast speed and high numerical accuracy, the calculation using the direct line density instead of the first derivative of the line density avoids numerical filtering of the electron density function for computing the CSR wakefield force.
[The calculation of the intraocular lens power based on raytracing methods: a systematic review].
Steiner, Deborah; Hoffmann, Peter; Goldblum, David
2013-04-01
A problem in cataract surgery consists in the preoperative identification of the appropriate intraocular lens (IOL) power. Different calculation approaches have been developed for this purpose; raytracing methods represent one of the most exact but also mathematically more challenging methods. This article gives a systematic overview of the different raytracing calculations available and described in the literature and compares their results. It has been shown that raytracing includes physical measurements and IOL manufacturing data but no approximations. The prediction error is close to zero and an essential advantage is the applicability to different conditions without the need of modifications. Compared to the classical formulae the raytracing methods are more precise overall, but due to the various data and property situations they are hardly comparable yet. The raytracing calculations represent a good alternative to the 3rd generation formulae. They minimize refractive errors, are wider applicable and provide better results overall, particularly in eyes with preconditions. PMID:23629771
A new calculation method for the number of radial slots of a Terfenol rod
Institute of Scientific and Technical Information of China (English)
HE XiPing; ZHANG Pin
2009-01-01
Terfenol is an ideal choice for medium to high power low frequency sonar. It can offer the transducer designer higher strain, higher power density, but the designer must be aware of the eddy current. To enhance efficiency of the barrel-stave transducer powered by a Terfenol rod, radial slots rather than laminations were used to control eddy currents in the Terfenol drive rod, and the effectiveness and the number of these slots were studied experimentally and calculated by finite element modeling. Based on the characteristic of vortex path, a new simple geometrical method to calculate the number of the radial slots of a Terfenol rod at the operating frequency is put forward in this paper. Moreover, the calculated results are in good agreement with those of using the finite element method (FEM) for the slotted Ter-fenol rod given by the literature. The method will save much cost to design Terfenol rod transducers.
Analysis of shielding calculation methods for 16- and 64-slice computed tomography facilities
Energy Technology Data Exchange (ETDEWEB)
Moreno, C; Cenizo, E; Bodineau, C; Mateo, B; Ortega, E M, E-mail: c_morenosaiz@yahoo.e [Servicio de RadiofIsica Hospitalaria, Hospital Regional Universitario Carlos Haya, Malaga (Spain)
2010-09-15
The new multislice computed tomography (CT) machines require some new methods of shielding calculation, which need to be analysed. NCRP Report No. 147 proposes three shielding calculation methods based on the following dosimetric parameters: weighted CT dose index for the peripheral axis (CTDI{sub w,per}), dose-length product (DLP) and isodose maps. A survey of these three methods has been carried out. For this analysis, we have used measured values of the dosimetric quantities involved and also those provided by the manufacturer, making a comparison between the results obtained. The barrier thicknesses when setting up two different multislice CT instruments, a Philips Brilliance 16 or a Philips Brilliance 64, in the same room, are also compared. Shielding calculation from isodose maps provides more reliable results than the other two methods, since it is the only method that takes the actual scattered radiation distribution into account. It is concluded therefore that the most suitable method for calculating the barrier thicknesses of the CT facility is the one based on isodose maps. This study also shows that for different multislice CT machines the barrier thicknesses do not necessarily become bigger as the number of slices increases, because of the great dependence on technique used in CT protocols for different anatomical regions.
Methods for reactor physics calculations for control rods in fast reactors
International Nuclear Information System (INIS)
The IAEA Specialists' Meeting on ''Methods for Reactor Physics Calculations for Control Rods in Fast Reactors'' was held in Winfrith, United Kingdom, on 6-8 December, 1988. The meeting was attended by 23 participants from nine countries. The purpose of the meeting was to review the current calculational methods and their accuracy as assessed by theoretical studies and comparisons with measurements, and then to identify the requirements for improved methods or additional studies and comparisons. The control rod properties or effects to be considered were their reactivity worths, their effect on the power distribution through the core, and the reaction rates and energy deposition both within and adjacent to the rods. The meeting was divided into five sessions, in the first of which each national delegation presented a brief overview of their programme of work on calculational methods for fast reactor control rods. In the next three sessions a total of seventeen papers were presented describing calculational methods and assessments of their accuracy. The final session was a discussion to draw conclusions regarding the current status of methods and the further developments and validation work required. A separate abstract was prepared for each of the 23 papers presented at the meeting. Refs, figs and tabs
Method for Calculating Performance of Three-Phase Line-Start Permanent-Magnet Synchronous Motor
Takegami, Tsuneo; Tsuboi, Kazuo; Hirotsuka, Isao; Nakamura, Masanori
A three-phase line-start permanent-magnet synchronous motor (three-phase LSPMM) is expected to operate with ultrahigh efficiency because it can start as an induction motor and can then operate as a permanent-magnet synchronous motor. In a previous study, we developed a practical analytical theory for a three-phase LSPMM on the basis of a tensor analysis. Then, we developed (1) a method for calculating the asynchronous starting characteristics and synchronous operating characteristics of the three-phase LSPMM on the basis of the developed analytical theory and (2) a method for determining the constants of the three-phase LSPMM. Herein, we report the results of a comparison between the calculated and measured asynchronous starting characteristics and synchronous operating characteristics of a test three-phase LSPMM. The comparison results show that the developed calculation method is highly efficient and that the results obtained by using it are sufficiently precise, and therefore, the method is suitable for practical use. Furthermore, we propose a method for improving the starting performance of the three-phase LSPMM, on the basis of simulations performed using the calculation method.
Improved method for calculating neoclassical transport coefficients in the banana regime
Energy Technology Data Exchange (ETDEWEB)
Taguchi, M., E-mail: taguchi.masayoshi@nihon-u.ac.jp [College of Industrial Technology, Nihon University, Narashino 275-8576 (Japan)
2014-05-15
The conventional neoclassical moment method in the banana regime is improved by increasing the accuracy of approximation to the linearized Fokker-Planck collision operator. This improved method is formulated for a multiple ion plasma in general tokamak equilibria. The explicit computation in a model magnetic field shows that the neoclassical transport coefficients can be accurately calculated in the full range of aspect ratio by the improved method. The some neoclassical transport coefficients for the intermediate aspect ratio are found to appreciably deviate from those obtained by the conventional moment method. The differences between the transport coefficients with these two methods are up to about 20%.
Integrating The Abc Method Of Costs Calculation And Cash Value Added
Marius Sorin DINCA; Gheorghita DINCA
2010-01-01
In our paper we intend to explore the possibility of integrating the ABC method of cost calcula-tion with cash based value measure, i.e. the Cash Value Added. Our purpose is to develop an instrument for the management of productive companies that will allow them to administrate the proc-ess of value creation at the level of individual products or services. The activity based costing (ABC) method of cost calculation can be extended to the way of allo-cating the capital costs to individual prod...
A Simple and Accurate Method for Calculating the Gaussian Beam Expansion Coefficients
Institute of Scientific and Technical Information of China (English)
LIU Wei; YANG Jun
2010-01-01
@@ The calculation of the diffraction field radiated from the ultrasonic transducer can be simplified by using the Gaussian beam expansion technique.The key problem of this technique is how to determine the coefficients of Gaussian functions.We present a simple and accurate optimization method to calculate the Gaussian beam expansion Coefficients.Half of the coefficients are obtained by solving linear equations.The other half are derived from the Fourier series expansion.Wave field simulation results demonstrate the validity of the new method.
A New Method to Calculate Centrifugal Pump Performance Parameters for Industrial Oils
Directory of Open Access Journals (Sweden)
mohammad hassan shojaeefard
2015-01-01
Full Text Available Pumping of oil instead of water using centrifugal pumps causes rapid increase in the hydraulic losses which results significant reduction in head and efficiency. Therefore, deriving analytical methods to calculate variation of pump performance parameters versus working fluid viscosity is very important. In the present study, a novel method is proposed to calculate the head (H, efficiency ( and input power ( in P based on the loss analysis for pumps using industrial oils. A computer code is developed based on represented method and the results of this method are compared with experimental results for a centrifugal pump of type KWP KBloc65- 200. The results show good agreement between analytical and experimental methods. Finally, using such computer code, diagrams of head, efficiency and input power versus working fluid viscosity are plotted.The results show an interesting point known as “sudden rising head” which is observed experimentally and numerically in literatures.
Calculations of Neutron Flux Distributions by Means of Integral Transport Methods
International Nuclear Information System (INIS)
Flux distributions have been calculated mainly in one energy group, for a number of systems representing geometries interesting for reactor calculations. Integral transport methods of two kinds were utilised, collision probabilities (CP) and the discrete method (DIT). The geometries considered comprise the three one-dimensional geometries, planes, sphericals and annular, and further a square cell with a circular fuel rod and a rod cluster cell with a circular outer boundary. For the annular cells both methods (CP and DIT) were used and the results were compared. The purpose of the work is twofold, firstly to demonstrate the versatility and efficacy of integral transport methods and secondly to serve as a guide for anybody who wants to use the methods
An improved projected predictor-corrector method for Gd-bearing fuel burnup calculations
International Nuclear Information System (INIS)
The accuracy of the conventional predictor-corrector (PC) fuel depletion method breaks down for the Gd-bearing fuel when coarse time step is adopted. To resolve this issue, the projected predictor-corrector (PPC) method which assumes the reaction rates are linear functions of the nuclide's atom density, was proposed by Yamamoto and significant accuracy gain was achieved for Gd-bearing fuel depletion calculation. This paper proposes an improved PPC method, which assumes a linear relation between the microscopic reaction rate and the natural logarithm of the nuclide's atom density for nuclides 155Gd and 157Gd. Verification calculations are performed against a 17 × 17 PWR Gd-bearing fuel assembly test problem, numerical results demonstrate that once the time step is coarser than 25 days the new PPC method is better than the original PPC method. (authors)
An adjusted energy-saving quantity calculation method for building energy-efficient retrofit
Institute of Scientific and Technical Information of China (English)
王清勤; 孟冲
2009-01-01
Aiming at a comprehensive assessment of energy-saving retrofitting effect on existing buildings,a calculation method is developed to adjust energy-saving quantity in standard condition for comparison under the same conditions. A mathematical model,method theory and calculation steps are given. Error analysis results show that this method can be applied accurately to practical engineering projects. In a case study of energy-saving quantity assessment before and after retrofitting on a certain hospital in Shanghai,with energy simulation software TRNSYS,detailed application of this method is introduced and analyzed. The method is applied to the case of energy-saving quantity assessment to a hospital in Shanghai before and after retrofitting with the energy simulation software TRNSYS.
Application Of WIMS Code To Calculation Kartini Reactor Parameters By Pin-Cell And Cluster Method
International Nuclear Information System (INIS)
Analysis UZrH fuel element parameters calculation in Kartini Reactor by WIMS Code has been done. The analysis is done by pin cell and cluster method. The pin cell method is done as a function percent burn-up and by 8 group 3 region analysis and cluster method by 8 group 12 region analysis. From analysis and calculation resulted K∼ = 1.3687 by pin cell method and K∼ = 1.3162 by cluster method and so deviation is 3.83%. By pin cell analysis as a function percent burn-up at the percent burn-up greater than 59.50%, the multiplication factor is less than one (k∼ < 1) it is mean that the fuel element reactivity is negative
Electronic structure of Co-phthalocyanine calculated by GGA+U and hybrid functional methods
International Nuclear Information System (INIS)
Graphical abstract: Electronic structure of Co-phthalocyanine molecule has been calculated using GGA+U and B3LYP methods. The results are in good agreement with experimental observations. Abstract: Electronic structure calculations have been performed for the Co-phthalocyanine molecule using density functional theory (DFT) within the framework of Generalized Gradient Approximation (GGA). The electronic correlation in Co 3d orbitals is treated in terms of the GGA+U method in the framework of the Hubbard model. We find that for U = 6 eV, the calculated structural parameters as well as the spectral features are in good agreement with the experimental findings. From our calculation both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are dominated by the pyrrole carbon, with a HOMO-LUMO gap of about 1.4 eV. The GGA+U results obtained with U = 6 eV compare reasonably well with the calculations performed using Gaussian basis set and hybrid functionals in terms of ground state geometry, spin state and spectral features. The calculated valence band photoemission spectrum is in quite good agreement with the recently published experimental results.
International Nuclear Information System (INIS)
In order to calculate the more accurate top event probability from cutsets or minimal cut sets (MCSs) than the conventional method that adopts the rare event approximation (REA) or min cut upper bound (MCUB) calculation, advanced cutset upper bound estimator (ACUBE) software had been developed several years ago and shortly became a vital tool for calculating the accurate core damage frequency of nuclear power plants in probabilistic safety assessment (PSA). Usually, the whole cutsets in the industry PSA models cannot be converted into a Binary decision diagram (BDD) due to the limited computational memory. So, the ACUBE selects the major cutsets whose probabilities are larger than the others, and then converts the major cutsets into a BDD in order to calculate more accurate top event probability from cutsets. This study (1) suggests when and where the ACUBE should be employed by predicting the amount of overestimation of the top event probability depending on the cutset structure, (2) explains the details of the ACUBE algorithm, and (3) demonstrates the efficiency of the ACUBE by calculating the top event probability of some PSA cutsets. - Highlights: • EPRI report [32] introduces many successful events in the seismic PSA cutsets. • This results in drastically overestimated top event probability. • In order to overcome this problem, the author developed ACUBE software. • ACUBE calculation can be determined according to the cutset structure (Section 4). • ACUBE calculation removes unnecessary conservatism in the top event probability
Study of the embedded atom method of atomistic calculations for metals and alloys
International Nuclear Information System (INIS)
Two projects were completed in the past year. The stability of a series of binary alloys was calculated using the embedded-atom method (EAM) with an analytic form for two-body potentials derived previously. Both disordered alloys and intermetallic compounds with the L10 and L12 structures were studied. The calculated heats of solution of alloys of Cu, Ag, Au, Ni, and Pt were satisfactory, while results for alloys containing Pd were too high. Atomistic calculations using the EAM were also carried out for point defects in hcp metals. By comparison with results in the literature, it was found that many body effects from the EAM significantly alter predicted physical properties of hcp metals. For example, the EAM calculations yield anisotropic vacancy diffusion with greater vacancy mobility in the basal plane, and imply that diffusion will start at a lower fraction of the melting temperature
Cdiaph: Program for calculating reinforced concrete diaphragm with finite difference method
Directory of Open Access Journals (Sweden)
Lukić Predrag
2014-01-01
Full Text Available Works in soil requires making of supporting structures to ensure the stability of the field. Reinforced concrete diaphragms allow you to perform the most complex works in a safe manner. The current calculation practice of the effect and movement of diaphragms implied the manual approach to the calculation that requires a serious time commitment of engineers or the use of complex commercial software packages. This paper presents the program automation and acceleration of the process of calculating the effect, movement and rotation of reinforced concrete diaphragms. A software package Cdiaph has been developed, which with the finite difference method calculates and draws diagrams of force impact at the intersection (M and V, movement and rotation of the intersection (x and f and the recommended depth of foundation (D of reinforced concrete diaphragms.
Calculation method of quantum efficiency to TiO2 nanocrystal photocatalysis reaction
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The quantum yield is an important factor to evaluate the efficiency of photoreactor. This article gives an overall calculation method of the quantum efficiency(ф) and the apparent quantum efficiency(ф2) to the TiO2/UV photocatalysis system. Furthermore, for the immobility system (IS), the formulation of the faction of light absorbed by the TiO2 thin film is proposed so as to calculate the quantum efficiency by using the measured value and theoretic calculated value of transmissivity (T). For the suspension system(SS), due to the difficulty to obtain the absorption coefficient (α) of TiO2 particulates, the quantum efficiency is calculated by means of the relative photonic efficiency (ξr) and the standard quantum yield (фstandard).
Experimental tests and calculation methods for missile crashing effects on a reactor containment
International Nuclear Information System (INIS)
In the analysis of missile crashing on a reactor containment there are two main effects to be taken into account: the overall behaviour of the building; the local perforation. The overall behaviour of the building is easily calculated when the applied force as a function of time is known. Two calculation examples are presented. The local perforation is a much more difficult problem and experimental work is necessary. The report presents a series of perforation tests of concrete plates by cylindrical missiles with a flat nose. The aim of these tests is to extrapolate for the lower speeds the existing experimental correlations and to check the calculation methods. The calculations are made with the PASTEL code (Finite elements, implicit integration), with elastoplasticity of the reinforcing steel bars and the concrete. Various plastification and fracturation laws are tested. (Auth.)
An Efficient numerical method to calculate the conductivity tensor for disordered topological matter
Garcia, Jose H.; Covaci, Lucian; Rappoport, Tatiana G.
2015-03-01
We propose a new efficient numerical approach to calculate the conductivity tensor in solids. We use a real-space implementation of the Kubo formalism where both diagonal and off-diagonal conductivities are treated in the same footing. We adopt a formulation of the Kubo theory that is known as Bastin formula and expand the Green's functions involved in terms of Chebyshev polynomials using the kernel polynomial method. Within this method, all the computational effort is on the calculation of the expansion coefficients. It also has the advantage of obtaining both conductivities in a single calculation step and for various values of temperature and chemical potential, capturing the topology of the band-structure. Our numerical technique is very general and is suitable for the calculation of transport properties of disordered systems. We analyze how the method's accuracy varies with the number of moments used in the expansion and illustrate our approach by calculating the transverse conductivity of different topological systems. T.G.R, J.H.G and L.C. acknowledge Brazilian agencies CNPq, FAPERJ and INCT de Nanoestruturas de Carbono, Flemish Science Foundation for financial support.
Method for calculating required shielding in medical x-ray rooms
International Nuclear Information System (INIS)
The new annual radiation dose limits - 20 mSv (previously 50 mSv) for radiation workers and 1 mSv (previously 5 mSv) for other persons - implies that the adequacy of existing radiation shielding must be re-evaluated. In principle, one could assume that the thicknesses of old radiation shields should be increased by about one or two half-value layers in order to comply with the new dose limits. However, the assumptions made in the earlier shielding calculations are highly conservative; the required shielding was often determined by applying the maximum high-voltage of the x-ray tube for the whole workload. A more realistic calculation shows that increased shielding is typically not necessary if more practical x-ray tube voltages are used in the evaluation. We have developed a PC-based calculation method for calculating the x-ray shielding which is more realistic than the highly conservative method formerly used. The method may be used to evaluate an existing shield for compliance with new regulations. As examples of these calculations, typical x-ray rooms are considered. The lead and concrete thickness requirements as a function of x-ray tube voltage and workload are also given in tables. (author)
A CT-based analytical dose calculation method for HDR 192Ir brachytherapy
International Nuclear Information System (INIS)
Purpose: This article presents an analytical dose calculation method for high-dose-rate 192Ir brachytherapy, taking into account the effects of inhomogeneities and reduced photon backscatter near the skin. The adequacy of the Task Group 43 (TG-43) two-dimensional formalism for treatment planning is also assessed. Methods: The proposed method uses material composition and density data derived from computed tomography images. The primary and scatter dose distributions for each dwell position are calculated first as if the patient is an infinite water phantom. This is done using either TG-43 or a database of Monte Carlo (MC) dose distributions. The latter can be used to account for the effects of shielding in water. Subsequently, corrections for photon attenuation, scatter, and spectral variations along medium- or low-Z inhomogeneities are made according to the radiological paths determined by ray tracing. The scatter dose is then scaled by a correction factor that depends on the distances between the point of interest, the body contour, and the source position. Dose calculations are done for phantoms with tissue and lead inserts, as well as patient plans for head-and-neck, esophagus, and MammoSite balloon breast brachytherapy treatments. Gamma indices are evaluated using a dose-difference criterion of 3% and a distance-to-agreement criterion of 2 mm. PTRANCT MC calculations are used as the reference dose distributions. Results: For the phantom with tissue and lead inserts, the percentages of the voxels of interest passing the gamma criteria (Pγ≥1) are 100% for the analytical calculation and 91% for TG-43. For the breast patient plan, TG-43 overestimates the target volume receiving the prescribed dose by 4% and the dose to the hottest 0.1 cm3 of the skin by 9%, whereas the analytical and MC results agree within 0.4%. Pγ≥1 are 100% and 48% for the analytical and TG-43 calculations, respectively. For the head-and-neck and esophagus patient plans, Pγ≥1 are ≥99
Advanced numerical methods for three dimensional two-phase flow calculations
Energy Technology Data Exchange (ETDEWEB)
Toumi, I. [Laboratoire d`Etudes Thermiques des Reacteurs, Gif sur Yvette (France); Caruge, D. [Institut de Protection et de Surete Nucleaire, Fontenay aux Roses (France)
1997-07-01
This paper is devoted to new numerical methods developed for both one and three dimensional two-phase flow calculations. These methods are finite volume numerical methods and are based on the use of Approximate Riemann Solvers concepts to define convective fluxes versus mean cell quantities. The first part of the paper presents the numerical method for a one dimensional hyperbolic two-fluid model including differential terms as added mass and interface pressure. This numerical solution scheme makes use of the Riemann problem solution to define backward and forward differencing to approximate spatial derivatives. The construction of this approximate Riemann solver uses an extension of Roe`s method that has been successfully used to solve gas dynamic equations. As far as the two-fluid model is hyperbolic, this numerical method seems very efficient for the numerical solution of two-phase flow problems. The scheme was applied both to shock tube problems and to standard tests for two-fluid computer codes. The second part describes the numerical method in the three dimensional case. The authors discuss also some improvements performed to obtain a fully implicit solution method that provides fast running steady state calculations. Such a scheme is not implemented in a thermal-hydraulic computer code devoted to 3-D steady-state and transient computations. Some results obtained for Pressurised Water Reactors concerning upper plenum calculations and a steady state flow in the core with rod bow effect evaluation are presented. In practice these new numerical methods have proved to be stable on non staggered grids and capable of generating accurate non oscillating solutions for two-phase flow calculations.
International Nuclear Information System (INIS)
The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared
McKechnie, Scott; Booth, George H; Cohen, Aron J; Cole, Jacqueline M
2015-05-21
The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared. PMID:26001454
Directory of Open Access Journals (Sweden)
A. I. Antonov
2012-02-01
Full Text Available Problem statement. Power objects (heat and power plants, district heat plants, and boiler plantsare located within the precincts of the settlements and are sources of elevated noise levels. Thereuponthere is a necessity of estimation of a noise conditions in the premises of thermal power stationsand in the territories adjoining to them. The process of formation of noise conditions in thethermal power station premises is a difficult multiple process, which requires sophisticated mathematicalmodels for its description. The existing methods do not provide obligatory accuracy ofcalculations. The development of the new methods is required.Results. The new combined method of noise calculation in industrial premises of the thermalpower stations is proposed. The method is based on the principles of division of glassy and diffusivecomponents of the reflected energy and their calculation, accordingly, with the help of a methodof tracing and a statistical energy method. The total condensation of sound energy in imputedpoints is determined by the power summation of all the components. For the method implementationa computer model is elaborated.Conclusions. The method proposed and the computer model of its implementation provide the solutionof problems of noise estimation in the premises of the thermal power stations and in the adjoiningareas. The accuracy of the calculations is sufficient for an objective estimation of noise andfor development of the measures on its reduction.
A new method for the calculation of Sommerfeld screening parameter 1 in x-ray spectra
Indian Academy of Sciences (India)
U D Misra; S Chaturvedi
2001-06-01
The paper describes a new method for the calculation of the Sommerfeld screening parameter 1. It requires neither the knowledge of the energy separations of spin doublet levels nor is it based on the application of the Hertz law. The only data required for the calculation are the experimental energy values of the level concerned for the series of elements belonging to the same subshell in which the element in the question is situated. As an illustration the values of 1 are calculated for the 1, 2 and 3 levels for elements belonging to the 4 subshell and these are found to be in excellent agreement with those published earlier by Gokhale and Misra. The method brings out the constancy of 1(23)-1(1) in a natural way and may thus be regarded as providing theoretical explanation of the Hertz law.
Doppler reactivity of thermal reactor cells calculated by space-dependent multiband method
International Nuclear Information System (INIS)
The Doppler reactivity worth is usually calculated using self-shielded cross section averaged over a fuel rod. In thermal reactor fuel cells, the approximation of constant cross section is not satisfactory because the self-shielding effect has space dependence within a fuel rod. We have calculated the Doppler reactivity by taking into account the space-dependent self-shielding and temperature distribution based on multiband and compared with the Doppler reactivity calculated by using average self-shielded cross section. It is found that the conventional method overestimates the Doppler reactivity worth by 15-18% for UO2 and MOX fuel cells, because the conventional method overestimates the difference between the 238U microscopic capture cross section for two different linear heat-generation rates. (author)
A calculation method of plant similarity giving consideration to different plant features.
Ding, Wei-long; Wu, Shui-sheng; Max, Nelson; Wu, Fu-li; Xu, Li-feng
2015-12-21
A method to compute the similarity between different plants is proposed, using features of a plant׳s topological structure and peripheral contour, as well as its geometry. The topological structures are described using tree graphs, and their similarity can be calculated based on the edit distance of these graphs. The peripheral contour of a plant is abstracted by its three-dimensional convex hull, which is projected in several directions. The similarity of the different projections is calculated by an algorithm to compute the similarity of two-dimensional shapes. The similarity of the geometrical detail is computed by considering the geometrical properties of different level branches. Finally the overall similarity between different plants is calculated by combining these different similarity measures. The validity of proposed method is evaluated by detailed experiments. PMID:26408336
International Nuclear Information System (INIS)
We report the calculation of preliminary potential surfaces necessary to treat dissociative recombination (DR) of electrons with N2H+. We performed multi-reference, configuration interaction calculations with a large active space for N2H+ and N2H, using the GAMESS electronic structure code. Rydberg-valence coupling is strong in N2H, and a systematic procedure is desirable to isolate the appropriate dissociating, autoionizing states. We used the block diagonalization method, which requires only modest additional effort beyond the standard methodology. We treated both linear and bent geometries of the molecules, with N2 fixed at its equilibrium separation. The results indicate that the crossing between the dissociating neutral curve and the initial ion potential is not favorably located, suggesting that the direct mechanism for DR will be small. Dynamics calculations using the multi-configuration, time-dependent Hartree (MCTDH) method confirm this conclusion.
Optimization Method for Indoor Thermal Comfort Based on Interactive Numerical Calculation
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In order to implement the optimal design of the indoor thermal comfort based on the numerical modeling method, the numerical calculation platform is combined seamlessly with the data-processing platform, and an interactive numerical calculation platform which includes the functions of numerical simulation and optimization is established. The artificial neural network (ANN) and the greedy strategy are introduced into the hill-climbing pattern heuristic search process, and the optimizing search direction can be predicted by using small samples; when searching along the direction using the greedy strategy, the optimal values can be quickly approached. Therefore, excessive external calling of the numerical modeling process can be avoided,and the optimization time is decreased obviously. The experimental results indicate that the satisfied output parameters of air conditioning can be quickly given out based on the interactive numerical calculation platform and the improved search method, and the optimization for indoor thermal comfort can be completed.
A New Optimization Method for Centrifugal Compressors Based on 1D Calculations and Analyses
Directory of Open Access Journals (Sweden)
Pei-Yuan Li
2015-05-01
Full Text Available This paper presents an optimization design method for centrifugal compressors based on one-dimensional calculations and analyses. It consists of two parts: (1 centrifugal compressor geometry optimization based on one-dimensional calculations and (2 matching optimization of the vaned diffuser with an impeller based on the required throat area. A low pressure stage centrifugal compressor in a MW level gas turbine is optimized by this method. One-dimensional calculation results show that D3/D2 is too large in the original design, resulting in the low efficiency of the entire stage. Based on the one-dimensional optimization results, the geometry of the diffuser has been redesigned. The outlet diameter of the vaneless diffuser has been reduced, and the original single stage diffuser has been replaced by a tandem vaned diffuser. After optimization, the entire stage pressure ratio is increased by approximately 4%, and the efficiency is increased by approximately 2%.
International Nuclear Information System (INIS)
This report provides absorbed dose rate and photon fluence rate distributions in rock salt around 30 testwise emplaced canisters containing high-level radioactive material (HAW project) and around a single canister containing radioactive material of a lower activity level (INHAW experiment). The site of this test emplacement was located in test galleries at the 800-m-level in the Asse salt mine. The data given were calculated using a Monte Carlo method simulating photon transport in complex geometries of differently composed materials. The aim of these calculations was to enable determination of the dose absorbed in any arbitrary sample of salt to be further examined in the future with sufficient reliability. The geometry of the test arrangement, the materials involved and the calculational method are characterised and the results are shortly described and some figures presenting selected results are shown. In the appendices, the results for emplacement of the highly radioactive canisters are given in tabular form. (orig.)
International Nuclear Information System (INIS)
In view of the problems of SDR and Tim-Coates models in calculating permeability using nuclear magnetic resonance logging data, based on the fact that nuclear magnetic resonance T2 distribution and capillary pressure curves reflect the reservoir pore structure, a method was presented to calculate reservoir permeability using nuclear magnetic resonance logging and capillary pressure data. The correlation between Swanson parameter and permeability was established by comparing 31 core samples which were measured by mercury penetration and nuclear magnetic resonance logging. Considering the problem that capillary pressure data are limited by their quantity, the good correlativity between T2 geometric mean value of lateral relaxation time of nuclear magnetic resonance and Swanson parameter can be used to determine the Swanson parameter and to calculate reservoir permeability consecutively. The processing of the data in well A yields a permeability closer to the result of core analysis, and this indicates the accuracy of the method. (authors)
An improved method for calculating force distributions in moment-stiff timber connections
DEFF Research Database (Denmark)
Ormarsson, Sigurdur; Blond, Mette
2012-01-01
An improved method for calculating force distributions in moment-stiff multi-dowel timber connections is presented, a method based on use of three-dimensional finite element simulations of timber connections subjected to moment action. The study that was carried out aimed at determining how the...... slip modulus varies with the angle between the direction of the dowel forces and the fibres in question, as well as how the orthotropic stiffness behaviour of the wood material affects the direction and the size of the forces. It was assumed that the force distribution generated by the moment action...... taking place strives to minimize the slip rotation between the separate members of a given timber connection. The results of modified hand calculations and of the corresponding finite element calculations that were performed were found to agree rather closely, and to differ remarkably from the results of...
Calculation Method for the Projection of Future Spent Nuclear Fuel Discharges
International Nuclear Information System (INIS)
This report describes the calculation method developed for the projection of future utility spent nuclear fuel (SNF) discharges in regard to their timing, quantity, burnup, and initial enrichment. This projection method complements the utility-supplied RW-859 data on historic discharges and short-term projections of SNF discharges by providing long-term projections that complete the total life cycle of discharges for each of the current U.S. nuclear power reactors. The method was initially developed in mid-1999 to update the SNF discharge projection associated with the 1995 RW-859 utility survey (CRWMS M and O 1996). and was further developed as described in Rev. 00 of this report (CRWMS M and O 2001a). Primary input to the projection of SNF discharges is the utility projection of the next five discharges from each nuclear unit, which is provided via the revised final version of the Energy Information Administration (EIA) 1998 RW-859 utility survey (EIA 2000a). The projection calculation method is implemented via a set of Excel 97 spreadsheets. These calculations provide the interface between receipt of the utility five-discharge projections that are provided in the RW-859 survey, and the delivery of projected life-cycle SNF discharge quantities and characteristics in the format requisite for performing logistics analysis to support design of the Civilian Radioactive Waste Management System (CRWMS). Calculation method improvements described in this report include the addition of a reactor-specific maximum enrichment-based discharge burnup limit. This limit is the consequence of the enrichment limit, currently 5 percent. which is imposed as a Nuclear Regulatory Commission (NRC) license condition on nuclear fuel fabrication plants. In addition, the calculation method now includes the capability for projecting future nuclear plant power upratings, consistent with many such recent plant uprates and the prospect of additional future uprates. Finally. this report
Directory of Open Access Journals (Sweden)
A. Yu. Zhuravlev
2016-04-01
Full Text Available Purpose. The work is intended to investigate the electromagnetic processes in impedance bond in order to improve noise immunity of track circuits (TC for safe railway operation. Methodology. To achieve this purpose the methods of scientific analysis, mathematical modelling, experimental study, a large-scale simulation were used. Findings. The work examined the interference affecting the normal performance of track circuits. To a large extent, part of track circuit damages account for failures in track circuit equipment. Track circuit equipment is connected directly to the track line susceptible to traction current interference, which causes changes in its electrical characteristics and electromagnetic properties. Normal operability, performance of the main operating modes of the track circuit is determined by previous calculation of its performance and compilation of regulatory tables. The classical method for determination of track circuit parameters was analysed. The classical calculation method assumes representation of individual sections of the electrical track circuit using the quadripole network with known coefficients, usually in the A-form. Determining the coefficients of linear element circuit creates no metrological or mathematical difficulties. However, in circuits containing nonlinear ferromagnets (FM, obtaining the coefficients on the entire induction change range in the cores is quite a difficult task because the classical methods of idling (I and short circuit (SC are not acceptable. This leads to complicated methods for determining both the module and the arguments of quadripole network coefficients. Instead of the classical method, the work proposed the method for calculating the track circuit dependent on nonlinear properties of ferromagnets. Originality. The article examines a new approach to the calculation of TC taking into account the losses in ferromagnets (FM, without determination of equivalent circuit quadripole
Strong, Stuart L.; Meade, Andrew J., Jr.
1992-01-01
Preliminary results are presented of a finite element/finite difference method (semidiscrete Galerkin method) used to calculate compressible boundary layer flow about airfoils, in which the group finite element scheme is applied to the Dorodnitsyn formulation of the boundary layer equations. The semidiscrete Galerkin (SDG) method promises to be fast, accurate and computationally efficient. The SDG method can also be applied to any smoothly connected airfoil shape without modification and possesses the potential capability of calculating boundary layer solutions beyond flow separation. Results are presented for low speed laminar flow past a circular cylinder and past a NACA 0012 airfoil at zero angle of attack at a Mach number of 0.5. Also shown are results for compressible flow past a flat plate for a Mach number range of 0 to 10 and results for incompressible turbulent flow past a flat plate. All numerical solutions assume an attached boundary layer.
International Nuclear Information System (INIS)
High spatial resolution tomographic reconstructions with several thousand pixels were performed by three different reconstruction algorithms. To overcome the increased ill posedness due to the use of a large number of pixels, the fast maximum entropy method (MEM) and the Phillips-Tikhonov method were used without any biasing information. The developed spatially resolved fast tomography codes were tested with the KSTAR plasma-like emissivity phantom and the TCV soft x-ray data. The reconstruction results were compared with those by the minimum Fisher information method, and these three methods shows the reliable reconstruction results. Speedup of the calculation was attempted by implementing the parallel computing technique via MATHLINK in the fast MEM code written in the MATHEMATICA language. The calculation speed of the fast MEM code was improved by about ten times without loss of accuracy despite the large number of pixels (2700 and 3500 pixels)
Comparison of Different Methods for Calculating Gyrotron Quasi-Optical Mode Converters
Gashturi, A. P.; Chirkov, A. V.; Denisov, G. G.; Paveliev, A. B.
2013-01-01
This paper presents the use of combination of three methods for calculation and synthesis of high-efficiency microwave mode converters, such as radiators of gyrotrons. The analytical method yields immediate estimates of mode converter dimensions, the Scalar Integral Equation (SIE) allows one to synthesize efficiently the optimal profile of the mode converter, and the most accurate Electric Field Integral Equation (EFIE) is used to check all transmission characteristics of the converter including calculations of reflection and cross-polarization. The combination of these three methods is an optimal for the mode converter design. Just so the launcher was designed for a quasi-optical mode converter used in the 60 GHz gyrotron in the TE7,3 operating mode. The simulation results agree well with the measured data. The paper also presents for the first time an accurate derivation of the SIE method.
A calculation method of cracking moment for the high strength concrete beams under pure torsion
Indian Academy of Sciences (India)
Metin Husem; Ertekin Oztekin; Selim Pul
2011-02-01
In this study, a method is given to calculate cracking moments of high strength reinforced concrete beams under the effect of pure torsion. To determine the method, both elastic and plastic theories were used. In this method, dimensions of beam cross-section were considered besides stirrup and longitudinal reinforcements. Two plain high strength concrete (without reinforcement) and eight high strength reinforced concrete beams which have two different cross-sections (150 × 250 mm and 150 × 300 mm) were produced to examine the validity of the proposed method. The predictions of the proposed approach for the calculation of the cracking moment of beams under pure torsion were compared with the experimental and the analytical results of previous studies. From these comparisons it is concluded that the predictions of the proposed equations for the cracking moment of plain and reinforced high strength concrete beams under pure torsion are closer to the experimental data compared to the analytical results of previous theories.
Comparison of three methods for calculation of electron transfer probability in H+ + Ne
International Nuclear Information System (INIS)
We have developed a theoretical model of ion-atom collisions where we described electron dynamics by the time-dependent density-functional theory (TDDFT) and the ion dynamics by classical mechanics through the Ehrenfest method. We have compared three methods to calculate the probability of electron transfer during H+ + Ne collision. By discussing these issues we shall be able to understand how these methods work, what their limitations are and whether they admit of any improvements. -- Highlights: ► We have developed a theoretical model of ion-atom collisions based on TDDFT. ► We have compared three methods to calculate the probability of electron transfer in H+ + Ne. ► Electron transfer cross sections showed a good agreement with available experimental data.
Applying Upwind Godunov Methods to Calculate Two—Phase Mixture Conservation Laws
Zeidan, D.
2010-09-01
This paper continues a previous work (ICNAAM 2009; AIP Conference Proceedings, 1168, 601-604) on solving a hyperbolic conservative model for compressible gas—solid mixture flow using upwind Godunov methods. The numerical resolution of the model from Godunov first—order upwind and MUSCL—Hancock methods are reported. Both methods are based on the HLL Riemann solver in the framework of finite volume techniques. Calculation results are presented for a series of one—dimensional test problems. The results show that upwind Godunov methods are accurate and robust enough for two—phase mixture conservation laws.
A contribution to the method of fast reactor thermal output calculation
International Nuclear Information System (INIS)
The method of stating the heat sources is discussed as being one of the factors influencing the accuracy of the thermal output calculation of fast reactors. The distribution of heat sources in the core and in other inner parts of the fast reactor is described using the least square fit method. Relations are derived of outputs of both individual components of fuel elements and of whole inner parts of the reactor. A comparison is made of various methods used for obtaining source integrals. The optimum integration method was found. (author)
Prying Force Calculation and Design Method for T-shaped Tensile Connector with High Strength Bolt
Institute of Scientific and Technical Information of China (English)
Zhaoxin Hou; Guohong Huang; Chao Gong
2015-01-01
In order to establish the design method for T⁃shaped tensile connector with high strength bolt, the theoretical analysis is carried out. Firstly, it analyzes the performance of the connector and establishes prying force calculation model. Based on the model, prying force equation and function between bolt prying force and flange thickness is derived, and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally, two simplified design methods of the connector are proposed, which are bolt pulling capacity method and flange plate bending capacity method.
A coupling method of subgroup and wavelet expansion for the resonance parameter calculation
International Nuclear Information System (INIS)
Owing to their geometric flexibility, subgroup method and wavelet expansion method have become attractive approaches to obtain effective self-shielding microscopic cross sections within resonance energy groups for geometrically complex problems. However, the subgroup method is good in the dense resonance range, while the wavelet expansion method is good in the sparse resonance range. In order to get the resonance parameter in the whole resonance energy range more accurately and effectively, this paper developed a new coupling resonance calculation model based on subgroup method and wavelet expansion method. In this coupling model, the subgroup method is employed to handle the higher resonance energy groups, and the wavelet expansion method is employed to handle the lower resonance energy groups. At the coupling interface, they are coupled by transferring scattering source. In order to verify the coupling model, a series of benchmark problems are calculated in this paper. It is demonstrated that compared with subgroup method and wavelet expansion method respectively, this coupling resonance model has the ability to provide more exactly self-shielding microscopic cross sections in the whole resonance energy range while keeping enough efficiency. (author)
A simple method using MAFIA to calculate external Q values of waveguide-loaded cavities
Kageyama, Tatsuya
1989-06-01
A fundamental theory on waveguide-loaded cavities in the book of Microwave Electronics by Slater was applied to numerical calculation with MAFIA of the external Q value of a klystron output cavity. This method is also applicable to accelerating structures with slots for damping out higher modes as proposed for future linear colliders.
International Nuclear Information System (INIS)
We discuss an improved technique for handling the Coulomb singularity in the momentum space Hartree-Fock equations. This method improves the quality of numerical orbitals by significantly reducing the integration error. We also examine a number of ways of reducing truncation error in these calculations. copyright 1988 Academic Press, Inc
Energy Technology Data Exchange (ETDEWEB)
Alexander, S.A.; Coldwell, R.L.; Monkhorst, H.J.
1988-06-01
We discuss an improved technique for handling the Coulomb singularity in the momentum space Hartree-Fock equations. This method improves the quality of numerical orbitals by significantly reducing the integration error. We also examine a number of ways of reducing truncation error in these calculations. copyright 1988 Academic Press, Inc.
The background cross section method for calculating the epithermal neutron spectra
International Nuclear Information System (INIS)
We have developed a new methodology to the multigroup constants calculations, for thermal and fast reactors. The method to obtain the constants is extremely fast and simple, and it avoid repeated computations of the detailed neutron spectrum for different cell configurations (composition, geometry and temperature). (author)
Calculating magnetic shielding effectiveness for high-power dc comparator by magnetic circuit method
Institute of Scientific and Technical Information of China (English)
WANG Xiao-wei; REN Shi-yan
2007-01-01
Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comparators when an external radial magnetic field is added. The mathematical relationship between the magnetic shielding effectiveness and the parameters of the magnetic shielding body were obtained. To verify the validity of the calculation method, we developped a procedure to measure the magnetic shielding effectiveness of the magnetic body by measuring the induction voltage of the detection winding instead of the magnetic intensity at a point in the magnetic shielding body, making the manipulation much easier. The result calculated with the magnetic circuit method turns out to be closer to the measured one compared with that calculated with a conventional algorithm proposed by Ren, suggesting that the magnetic circuit method is an applicable tool for estimating the toroidal cavity magnetic shielding effectiveness of a heavy current comparator when a radial magnetic field is added.
Comparison of different mass transport calculation methods for wind erosion quantification purposes
Quantitative estimation of the material transported by the wind is essential in the study and control of wind erosion, although methods for its calculation are still controversial. Sampling the dust cloud at discrete heights, fitting an equation to the data, and integrating this equation from the so...
A 'hybrid' method for calculating the topological susceptibility in lattice QCD
International Nuclear Information System (INIS)
We propose a method for calculating the topological susceptibility in lattice QCD, based on the use of a smearing procedure before the actual determination of the geometrical topological charge. We also present very preliminary results: they are consistent with the hypothesis that a 'soft' smearing is sufficient to avoid the contribution of 'unphysical' fluctuations to the topological susceptibility. (orig.)
A computer program for unilateral renal clearance calculation by a modified Oberhausen method
International Nuclear Information System (INIS)
A FORTAN program is presented which, on the basis of data obtained with NUKLEOPAN M, calculates the glomerular filtration rate with sup(99m)Tc-DTPA, the unilateral effective renal plasma flow with 131I-hippuran, and the parameters for describing the isotope rephrogram (ING) with 131I-hippuran. The results are calculated fully automatically upon entry of the data, and the results are processed and printed out. The theoretical fundamentals of ING and whole-body clearance calculation are presented as well as the methods available for unilateral clearance calculation, and the FORTAN program is described in detail. The standard values of the method are documented, as well as a comparative gamma camera study of 48 patients in order to determine the accuracy of unilateral imaging with the NUKLEOPAN M instrument, a comparison of unilateral clearances by the Oberhausen and Taplin methods, and a comparison between 7/17' plasma clearance and whole-body clearance. Problems and findings of the method are discussed. (orig./MG)
Hagedorn, Linda Serra
1998-01-01
A study explored two distinct methods of calculating a precise measure of gender-based wage differentials among college faculty. The first estimation considered wage differences using a formula based on human capital; the second included compensation for past discriminatory practices. Both measures were used to predict three specific aspects of…
Heat Conduction Analysis in a Tissue Phantom Calculated by FDTD and HCE Method
Endoh, Nobuyuki; Tsuchiya, Takenobu; Saito, Yoshikazu; Ishizeki, Takahiro
2005-03-01
In order to study hyperthermia in tissue, it is important to predict accurately the heat distribution. This paper describes a preliminary study of the comparison between simulation and experiment for heat conduction in a simple tissue phantom. Since it is well known that the heat increase in tissue depends on the sound intensity and the absorption coefficient, the sound pressure distribution is calculated using a Finite Difference Time Domain (FDTD) method. The thermal diffusion profile in tissue generated by the energy of the sound pulse is also simulated using the Heat Conduction Equation (HCE) method. The calculation area is 100 × 40 [mm]. The simple tissue phantom is made of agar, water and graphite. The phantom whose attenuation coefficient is 1.1 dB/cm/MHz is placed in a temperature controlled water bath. This is kept at 37 degrees [C] while sound pulses of 1 MHz are emitted over 10 minutes. Temperatures at six points on the acoustic axis are measured in the phantom. The calculation and experiment results are compared to confirm the accuracy of the proposed method. As a result, the calculation results show the validity of the combined FDTD-HCE method for thermal conduction analysis.
Heat Conduction Analysis in a Tissue Phantom Calculated by FDTD and HCE Method
International Nuclear Information System (INIS)
In order to study hyperthermia in tissue, it is important to predict accurately the heat distribution. This paper describes a preliminary study of the comparison between simulation and experiment for heat conduction in a simple tissue phantom. Since it is well known that the heat increase in tissue depends on the sound intensity and the absorption coefficient, the sound pressure distribution is calculated using a Finite Difference Time Domain (FDTD) method. The thermal diffusion profile in tissue generated by the energy of the sound pulse is also simulated using the Heat Conduction Equation (HCE) method. The calculation area is 100 x 40 [mm]. The simple tissue phantom is made of agar, water and graphite. The phantom whose attenuation coefficient is 1.1 dB/cm/MHz is placed in a temperature controlled water bath. This is kept at 37 deg. [C] while sound pulses of 1 MHz are emitted over 10 minutes. Temperatures at six points on the acoustic axis are measured in the phantom. The calculation and experiment results are compared to confirm the accuracy of the proposed method. As a result, the calculation results show the validity of the combined FDTD-HCE method for thermal conduction analysis
Sareni, Bruno; Krähenbühl, Laurent; Beroual, Abderrahmane; Nicolas, Alain; Brosseau, C.
1997-01-01
We present a numerical method based upon the resolution of boundary integral equations for the calculation of the effective permittivity of a lossless composite structure consisting of a two component mixture, each with its own dielectric anti shape characteristics. The topological arrangements considered are periodic lattices inhomogeneities. Our numerical simulations are compared to the effective medium approach and with results of previous works.
A collocation method for surface tension calculations with the density gradient theory
DEFF Research Database (Denmark)
Larsen, Peter Mahler; Maribo-Mogensen, Bjørn; Kontogeorgis, Georgios M.
2016-01-01
Surface tension calculations are important in many industrial applications and over a wide range of temperatures, pressures and compositions. Empirical parachor methods are not suitable over a wide condition range and the combined use of density gradient theory with equations of state has been pr...
A Method to Calculate the Surface Tension of a Cylindrical Droplet
Wang, Xiaosong; Zhu, Ruzeng
2010-01-01
The history of Laplace's equations for spherical and cylindrical droplets and the concept of dividing surface in Gibbs' thermodynamic theory of capillary phenomena are briefly reviewed. The existing theories of surface tensions of cylindrical droplets are briefly reviewed too. For cylindrical droplets, a new method to calculate the radius and the…
Three-dimensional whole core transport calculation method and performance of the DeCART code
International Nuclear Information System (INIS)
The three-dimensional (3D) transport calculation method implemented in a whole core neutron transport code DeCART is presented and its performance is examined in terms of solution accuracy and execution speed. The 3D flux calculation in DeCART is based on a transverse-integration method in which the radial and axial dependencies are handled separately. The radial dependence is resolved by the elaborated two-dimensional method of characteristics (MOC) whereas the axial dependence is dealt with the simple one-dimensional diffusion model. The global balance of the 3D flux distribution is incorporated by the coarse mesh finite difference (CMFD) formulation. It is shown that the CMFD formulation enables the approximate three-dimensional transport calculation through the transverse-integration, and furthermore it is very effective in achieving rapid convergence. The accuracy of the approximate 3D whole-core transport calculation method is proved by analyzing rodded variations of the C5G7 MOX heterogeneous core benchmark problem for which Monte Carlo solutions are generated as the reference
Energy Savings Calculation Methods under Article 7 of the Energy Efficiency Directive
LABANCA NICOLA; BERTOLDI PAOLO
2015-01-01
The present report aims to provide an overview of the main issues at stake with the calculation methods for energy savings generated by measures implemented by EU Member States under Article 7 of the Directive 2012/27/EU on Energy Efficiency (EED).
An Increment Method of Calculation of Melting Temperatures of Ionic Crystals
International Nuclear Information System (INIS)
A new increment method for calculation of melting temperatures (Tm) of binary inorganic ionic crystalline compounds has been suggested. On the basis of rather simple mathematic relationship the Tm for the majority of these compounds can be defined by the accuracy of no less than 10%. (author)
Calculation of the Centre of Gravity of the Cone Utilizing the Method of Archimedes
Magnaghi, C. P.; Assis, A. K. T.
2012-01-01
Archimedes calculated the centre of gravity of the cone but the proof of this theorem is not extant in his works. Knorr made a reconstruction of this proof utilizing geometrical arguments. This paper proves this theorem by means of a physical demonstration utilizing the law of the lever, and by adapting from Archimedes the method of mechanical…
Jia, L. Y.; Zelevinsky, V. G.
2012-01-01
Recently a procedure by generalized density matrix (GDM) is proposed for calculating a collective/bosonic Hamiltonian microscopically from the shell-model Hamiltonian. In this work we examine the validity of the method by comparing the GDM results with that of the exact shell-model diagonalization in a number of models. It is shown that the GDM method reproduces the low-lying collective states quite well, both for energies and transition rates, across the whole region going from vibrational t...
A New Method with General Diagnostic Utility for the Calculation of Immunoglobulin G Avidity
Korhonen, Maria H.; Brunstein, John; Haario, Heikki; Katnikov, Alexei; Rescaldani, Roberto; Hedman, Klaus
1999-01-01
The reference method for immunoglobulin G (IgG) avidity determination includes reagent-consuming serum titration. Aiming at better IgG avidity diagnostics, we applied a logistic model for the reproduction of antibody titration curves. This method was tested with well-characterized serum panels for cytomegalovirus, Epstein-Barr virus, rubella virus, parvovirus B19, and Toxoplasma gondii. This approach for IgG avidity calculation is generally applicable and attains t...
A Simple Method for Calculating a Planet's Mean Annual Insolation by Latitude
Nadeau, Alice
2015-01-01
Common methods for calculating a planet's annual insolation by latitude have relied on computationally heavy or complex computer algorithms. In this paper, we show that mean annual insolation by latitude of a planet with obliquity angle $\\beta$ can be found by taking the definite integral of a function of longitude. This leads to faster computations and more accurate results. We discuss differences between our method and selected computational results for insolation found in the literature.
Eberle, A.
1978-01-01
Analysis of the pressure minimum integral in the calculation of three-dimensional potential flow around wings makes it possible to use non-rectangular mesh networks for distributing the three-dimensional potential into discrete points. The method is comparatively easily expanded to the treatment of realistic airplane configurations. Shock-pressure affected pressure distributions on any wings are determined with accuracy using this method.
Beam-chamber interaction in accelerators. Methods for calculating coupling impedances
International Nuclear Information System (INIS)
A review of methods for calculating the coupling impedances of the vacuum chamber of accelerators is given. The definitions of the coupling impedances, their properties and relations to the wake potentials are discussed in detail. The main attention is paid to the techniques applied at low frequencies and in the resonant region. An attempt to classify these methods is made. The paper presents a collection of formulae and can be used as a reference guide. 126 refs.; 1 fig.; 1 tab
Star sub-pixel centroid calculation based on multi-step minimum energy difference method
Wang, Duo; Han, YanLi; Sun, Tengfei
2013-09-01
The star's centroid plays a vital role in celestial navigation, star images which be gotten during daytime, due to the strong sky background, have a low SNR, and the star objectives are nearly submerged in the background, takes a great trouble to the centroid localization. Traditional methods, such as a moment method, weighted centroid calculation method is simple but has a big error, especially in the condition of a low SNR. Gaussian method has a high positioning accuracy, but the computational complexity. Analysis of the energy distribution in star image, a location method for star target centroids based on multi-step minimum energy difference is proposed. This method uses the linear superposition to narrow the centroid area, in the certain narrow area uses a certain number of interpolation to pixels for the pixels' segmentation, and then using the symmetry of the stellar energy distribution, tentatively to get the centroid position: assume that the current pixel is the star centroid position, and then calculates and gets the difference of the sum of the energy which in the symmetric direction(in this paper we take the two directions of transverse and longitudinal) and the equal step length(which can be decided through different conditions, the paper takes 9 as the step length) of the current pixel, and obtain the centroid position in this direction when the minimum difference appears, and so do the other directions, then the validation comparison of simulated star images, and compare with several traditional methods, experiments shows that the positioning accuracy of the method up to 0.001 pixel, has good effect to calculate the centroid of low SNR conditions; at the same time, uses this method on a star map which got at the fixed observation site during daytime in near-infrared band, compare the results of the paper's method with the position messages which were known of the star, it shows that :the multi-step minimum energy difference method achieves a better
International Nuclear Information System (INIS)
Collisions between complex nuclei are described variationally in terms of the GCM with the aim to provide an evidence that it is a manageable calculational procedure. The variational principle of Kohn and Kato is used to derive the expression for the K matrix. The space of scattering states is spanned entirely by antisymmetrized products of shell model wave functions describing separate clusters; the generator coordinate is the separation between the two shell model potentials. Scattering boundary conditions are enforced by solving an integral equation for the channel GC amplitude in each open channel separately. The main part of evaluation of collision parameters is performed by calculating double integrals of a form factor between channel GC amplitudes. A theorem about a property of the form factors is proved which allows reduction of the amount of work needed to calculate double integrals. The application of the method to the elastic 3H to 4He scattering has shown the feasibility of the calculation. It is shown how an analysis of calculated scattering parameters and corresponding scattering states in terms of quasibound states enables one to make a consistent comparison with experiment and to extract some knowledge of the reaction mechanism. Finally a comparative list of the calculational procedures of the GCM and RGM for reactions is made. (author)
Calculation of nuclear parameters with the generator coordinate method and their interpretation
International Nuclear Information System (INIS)
Collisions between complex nuclei are described variationally in terms of the GCM with the aim of providing evidence that it is a manageable calculational procedure. The variational principle of Kohn and Kato is used to derive the expression for the K-matrix. The space of scattering states is spanned entirely by antisymmetrized products of shell-model wave functions describing separate clusters; the generator coordinate is the separation between the two shell-model potentials. Scattering boundary conditions are enforced by solving an integral equation for the channel GC amplitude in each open channel separately. The main part of evaluation of collision parameters is performed by calculating double integrals of a form factor between channel GC amplitudes. A theorem about a property of the form factors is proved which allows one to reduce the amount of work needed to calculate double integrals. Application of the method to elastic 3H to 4He scattering has shown the feasibility of the calculation. It is shown how an analysis of calculated scattering parameters and corresponding scattering states in terms of quasibound states enables one to make a consistent comparison with experiment and to extract some knowledge of the reaction mechanism. Finally a comparative list of the calculational procedures of the GCM and RGM for reactions is made. (orig.)
On the Calculation of Reactor Time Constants Using the Monte Carlo Method
International Nuclear Information System (INIS)
Full-core reactor dynamics calculation involves the coupled modelling of thermal hydraulics and the time-dependent behaviour of core neutronics. The reactor time constants include prompt neutron lifetimes, neutron reproduction times, effective delayed neutron fractions and the corresponding decay constants, typically divided into six or eight precursor groups. The calculation of these parameters is traditionally carried out using deterministic lattice transport codes, which also produce the homogenised few-group constants needed for resolving the spatial dependence of neutron flux. In recent years, there has been a growing interest in the production of simulator input parameters using the stochastic Monte Carlo method, which has several advantages over deterministic transport calculation. This paper reviews the methodology used for the calculation of reactor time constants. The calculation techniques are put to practice using two codes, the PSG continuous-energy Monte Carlo reactor physics code and MORA, a new full-core Monte Carlo neutron transport code entirely based on homogenisation. Both codes are being developed at the VTT Technical Research Centre of Finland. The results are compared to other codes and experimental reference data in the CROCUS reactor kinetics benchmark calculation. (author)
International Nuclear Information System (INIS)
Verification of calculated lung dose in an anthropomorphic phantom is performed using two dosimetry media. Dosimetry is complicated by factors such as variations in density at slice interfaces and appropriate position on CT scanning slice to accommodate these factors. Dose in lung for a 6 MV and 10 MV anterior-posterior field was calculated with a collapsed cone convolution method using an ADAC Pinnacle, 3D planning system. Up to 5% variations between doses calculated at the centre and near the edge of the 2 cm phantom slice positioned at the beam central axis were seen, due to the composition of each phantom slice. Validation of dose was performed with LiF thermoluminescent dosimeters (TLDs) and X-Omat V radiographic film. Both dosimetry media produced dose results which agreed closely with calculated results nearest their physical positioning in the phantom. The collapsed cone convolution method accurately calculates dose within inhomogeneous lung regions at 6 MV and 10 MV x-ray energy. (author)
International Nuclear Information System (INIS)
In the design of the reactor room for a fusion reactor, the cost of the room strongly depends on the thickness of the roof because the area of the roof is generally large. The roof thickness is mostly determined by the requirement to reduce the skyshine dose rate level at the site boundary below the assigned value. Therefore the accurate evaluation of the skyshine dose becomes important for the design of the reactor room. Skyshine dose for a D-T fusion reactor has been evaluated by a number of researchers but the agreement is not so good. In this report, the first collision source is used with two-dimensional SN transport method to form DOT3.5-GRTUNCL-DOT3.5 coupled calculation flow. The validity of the methodology was first shown by calculating the skyshine dose from a 14 MeV neutron source and comparing the calculated results with the measured results. This methodology was then used to calculate the skyshine dose for the Fusion Experimental Reactor (FER). The calculated results were compared with those from several other methods to clarify the mutual difference. (author)
Energy Technology Data Exchange (ETDEWEB)
Kraus, Terrence D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hunt, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2014-02-01
This report reviews the method recommended by the U.S. Food and Drug Administration for calculating Derived Intervention Levels (DILs) and identifies potential improvements to the DIL calculation method to support more accurate ingestion pathway analyses and protective action decisions. Further, this report proposes an alternate method for use by the Federal Emergency Radiological Assessment Center (FRMAC) to calculate FRMAC Intervention Levels (FILs). The default approach of the FRMAC during an emergency response is to use the FDA recommended methods. However, FRMAC recommends implementing the FIL method because we believe it to be more technically accurate. FRMAC will only implement the FIL method when approved by the FDA representative on the Federal Advisory Team for Environment, Food, and Health.
Diggs, Angela; Balachandar, S.
2016-05-01
The present work addresses numerical methods required to compute particle volume fraction or number density. Local volume fraction of the lth particle, αl, is the quantity of foremost importance in calculating the gas-mediated particle-particle interaction effect in multiphase flows. A general multiphase flow with a distribution of Lagrangian particles inside a fluid flow discretized on an Eulerian grid is considered. Particle volume fraction is needed both as a Lagrangian quantity associated with each particle and also as an Eulerian quantity associated with the grid cell for Eulerian-Lagrangian simulations. In Grid-Based (GB) methods the particle volume fraction is first obtained within each grid cell as an Eulerian quantity and then the local particle volume fraction associated with any Lagrangian particle can be obtained from interpolation. The second class of methods presented are Particle-Based (PB) methods, where particle volume fraction will first be obtained at each particle as a Lagrangian quantity, which then can be projected onto the Eulerian grid. Traditionally, the GB methods are used in multiphase flow, but sub-grid resolution can be obtained through use of the PB methods. By evaluating the total error, and its discretization, bias and statistical error components, the performance of the different PB methods is compared against several common GB methods of calculating volume fraction. The standard von Neumann error analysis technique has been adapted for evaluation of rate of convergence of the different methods. The discussion and error analysis presented focus on the volume fraction calculation, but the methods can be extended to obtain field representations of other Lagrangian quantities, such as particle velocity and temperature.
Output calculation of electron therapy at extended SSD using an improved LBR method
Energy Technology Data Exchange (ETDEWEB)
Alkhatib, Hassaan A.; Gebreamlak, Wondesen T., E-mail: wondtassew@gmail.com; Wright, Ben W.; Neglia, William J. [South Carolina Oncology Associates, Columbia, South Carolina 29210 (United States); Tedeschi, David J. [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States); Mihailidis, Dimitris [CAMC Cancer Center and Alliance Oncology, Charleston, West Virginia 25304 (United States); Sobash, Philip T. [The Medical University of South Carolina, Charleston, South Carolina 29425 (United States); Fontenot, Jonas D. [Department of Physics, Mary Bird Perkins Cancer Center, Baton Rouge, Louisiana 70809 (United States)
2015-02-15
Purpose: To calculate the output factor (OPF) of any irregularly shaped electron beam at extended SSD. Methods: Circular cutouts were prepared from 2.0 cm diameter to the maximum possible size for 15 × 15 applicator cone. In addition, two irregular cutouts were prepared. For each cutout, percentage depth dose (PDD) at the standard SSD and doses at different SSD values were measured using 6, 9, 12, and 16 MeV electron beam energies on a Varian 2100C LINAC and the distance at which the central axis electron fluence becomes independent of cutout size was determined. The measurements were repeated with an ELEKTA Synergy LINAC using 14 × 14 applicator cone and electron beam energies of 6, 9, 12, and 15 MeV. The PDD measurements were performed using a scanning system and two diodes—one for the signal and the other a stationary reference outside the tank. The doses of the circular cutouts at different SSDs were measured using PTW 0.125 cm{sup 3} Semiflex ion-chamber and EDR2 films. The electron fluence was measured using EDR2 films. Results: For each circular cutout, the lateral buildup ratio (LBR) was calculated from the measured PDD curve using the open applicator cone as the reference field. The effective SSD (SSD{sub eff}) of each circular cutout was calculated from the measured doses at different SSD values. Using the LBR value and the radius of the circular cutout, the corresponding lateral spread parameter [σ{sub R}(z)] was calculated. Taking the cutout size dependence of σ{sub R}(z) into account, the PDD curves of the irregularly shaped cutouts at the standard SSD were calculated. Using the calculated PDD curve of the irregularly shaped cutout along with the LBR and SSD{sub eff} values of the circular cutouts, the output factor of the irregularly shaped cutout at extended SSD was calculated. Finally, both the calculated PDD curves and output factor values were compared with the measured values. Conclusions: The improved LBR method has been generalized to
Output calculation of electron therapy at extended SSD using an improved LBR method
International Nuclear Information System (INIS)
Purpose: To calculate the output factor (OPF) of any irregularly shaped electron beam at extended SSD. Methods: Circular cutouts were prepared from 2.0 cm diameter to the maximum possible size for 15 × 15 applicator cone. In addition, two irregular cutouts were prepared. For each cutout, percentage depth dose (PDD) at the standard SSD and doses at different SSD values were measured using 6, 9, 12, and 16 MeV electron beam energies on a Varian 2100C LINAC and the distance at which the central axis electron fluence becomes independent of cutout size was determined. The measurements were repeated with an ELEKTA Synergy LINAC using 14 × 14 applicator cone and electron beam energies of 6, 9, 12, and 15 MeV. The PDD measurements were performed using a scanning system and two diodes—one for the signal and the other a stationary reference outside the tank. The doses of the circular cutouts at different SSDs were measured using PTW 0.125 cm3 Semiflex ion-chamber and EDR2 films. The electron fluence was measured using EDR2 films. Results: For each circular cutout, the lateral buildup ratio (LBR) was calculated from the measured PDD curve using the open applicator cone as the reference field. The effective SSD (SSDeff) of each circular cutout was calculated from the measured doses at different SSD values. Using the LBR value and the radius of the circular cutout, the corresponding lateral spread parameter [σR(z)] was calculated. Taking the cutout size dependence of σR(z) into account, the PDD curves of the irregularly shaped cutouts at the standard SSD were calculated. Using the calculated PDD curve of the irregularly shaped cutout along with the LBR and SSDeff values of the circular cutouts, the output factor of the irregularly shaped cutout at extended SSD was calculated. Finally, both the calculated PDD curves and output factor values were compared with the measured values. Conclusions: The improved LBR method has been generalized to calculate the output factor of
A method for three-dimensional multizone reactor calculations based on Nordheim-Scalettar approach
International Nuclear Information System (INIS)
A two-group diffusion procedure is proposed in this report as a contribution to the three-dimensional heterogeneous formalism for the multizone reactor criticality calculation. This method is based on Nordheim-Scalettar approach as well as on the procedure for three-dimensional analysis proposed by Chermak. The formalism presented here may be used for the calculations of the effect of absorber rods partly inserted in any zone of the multizone reactor system. The absorber rods may be divided in segments having various properties (author)
Preliminary Study on the Calculation Method of “Carbon Footprint”
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
At present, greenhouse effect has become a severe challenge of international society. In order to cope with this challenge, countries all over the world reached an agreement to develop low-carbon economy and create low-carbon society. As a new concept, "carbon footprint" emerged with the vigorous development of low-carbon economy, and its calculation method is related to the evaluation system of low carbon economy. In order to calculate "carbon footprint", "carbon subject" in the study was divided into ener...
Calculation of transition probabilities using the multiconfiguration Dirac-Fock method
International Nuclear Information System (INIS)
The performance of the multiconfiguration Dirac-Fock (MCDF) method in calculating transition probabilities of atoms is reviewed. In general, the MCDF wave functions will lead to transition probabilities accurate to ∼ 10% or better for strong, electric-dipole allowed transitions for small atoms. However, it is more difficult to get reliable transition probabilities for weak transitions. Also, some MCDF wave functions for a specific J quantum number may not reduce to the appropriate L and S quantum numbers in the nonrelativistic limit. Transition probabilities calculated from such MCDF wave functions for nonrelativistically forbidden transitions are unreliable. Remedies for such cases are discussed
Calculation of transition probabilities using the multiconfiguration Dirac-Fock method
International Nuclear Information System (INIS)
The performance of the multiconfiguration Dirac-Fock (MCDF) method in calculating transition probabilities of atoms is reviewed. In general, the MCDF wave functions will lead to transition probabilities accurate to ∼10% or better for strong, electric-dipole allowed transitions for small atoms. However, it is more difficult to get reliable transition probabilities for weak transitions. Also, some MCDF wave functions for specific J quantum number may not reduce to the appropriate L and S quantum numbers in the nonrelativistic limit. Transition probabilities calculation from such MCDF wave functions for nonrelativistically forbidden transitions are unreliable. Remedies for such cases are discussed.
Calculation of NMR chemical shifts. 7. Gauge-invariant INDO method
Fukui, H.; Miura, K.; Hirai, A.
A gauge-invariant INDO method based on the coupled Hartree-Fuck perturbation theory is presented and applied to the calculation of 1H and 13C chemical shifts of hydrocarbons including ring compounds. Invariance of the diamagnetic and paramagnetic shieldings with respect to displacement of the coordinate origin is discussed. Comparison between calculated and experimental results exhibits fairly good agreement, provided that the INDO parameters of Ellis et al. (J. Am. Chem. Soc.94, 4069 (1972)) are used with the inclusion of all multicenter one-electron integrals.
International Nuclear Information System (INIS)
The simplest method for the calculation of retention indices in temperature programmed gas chromatography consists in using a polygonal interpolation (IL). Irregularities in the shape of the curve thus sketched out are attenuated while processing calibration data with B-splines (iBSI), or Bezier curves (I'mBe), of different orders (i; m). Whereas Bezier smoothing yields retention indices more consistent with the scheme of this parameter, it results in higher scattering of the calculated data. The best quality of fit is observed for the interpolation by B-spline of order 2. (author)
Pennec, Fabienne; Alzina, Arnaud; Tessier-Doyen, Nicolas; Naitali, Benoit; Smith, David S.
2012-11-01
This work is about the calculation of thermal conductivity of insulating building materials made from plant particles. To determine the type of raw materials, the particle sizes or the volume fractions of plant and binder, a tool dedicated to calculate the thermal conductivity of heterogeneous materials has been developped, using the discrete element method to generate the volume element and the finite element method to calculate the homogenized properties. A 3D optical scanner has been used to capture plant particle shapes and convert them into a cluster of discret elements. These aggregates are initially randomly distributed but without any overlap, and then fall down in a container due to the gravity force and collide with neighbour particles according to a velocity Verlet algorithm. Once the RVE is built, the geometry is exported in the open-source Salome-Meca platform to be meshed. The calculation of the effective thermal conductivity of the heterogeneous volume is then performed using a homogenization technique, based on an energy method. To validate the numerical tool, thermal conductivity measurements have been performed on sunflower pith aggregates and on packed beds of the same particles. The experimental values have been compared satisfactorily with a batch of numerical simulations.
International Nuclear Information System (INIS)
Highlights: • A method for handling external feed in depletion calculations with CRAM. • Source term can have polynomial or exponentially decaying time-dependence. • CRAM with source term and adjoint capability implemented to ORIGEN in SCALE. • The new solver is faster and more accurate than the original solver of ORIGEN. - Abstract: A method for including external feed with polynomial time dependence in depletion calculations with the Chebyshev Rational Approximation Method (CRAM) is presented and the implementation of CRAM to the ORIGEN module of the SCALE suite is described. In addition to being able to handle time-dependent feed rates, the new solver also adds the capability to perform adjoint calculations. Results obtained with the new CRAM solver and the original depletion solver of ORIGEN are compared to high precision reference calculations, which shows the new solver to be orders of magnitude more accurate. Furthermore, in most cases, the new solver is up to several times faster due to not requiring similar substepping as the original one
Refinement of the sub-structure method for integral transport calculations
International Nuclear Information System (INIS)
A new generalization of the interface-current method for coupling two-dimensional heterogeneous assemblies, called sub-structures, has been developed. The method has been designed for fine-structure burn-up calculations in very heterogeneous media of large size. For the calculations the medium is divided into rectangular sub-structures, which can have internal symmetries, containing rectangular and/or cylindrical structure elements, divided into homogeneous zones. A zone-wise flat or linear expansion is used to formulate a direct collision-probability problem within each sub-structure. The sub-structures are coupled by making a piece-wise uniform or linear expansion for the partial currents entering and leaving the sub-structures. The method has also been used to implement an approximate piece-wise isotropic reflexion for two dimensional x-y collision probabilities calculations. The accuracies and computing times achieved are illustrated by one-group fixed source numerical calculations for a typical 7x7 pin PWR assembly as well as for a set of fuel slabs imbedded in water moderator
International Nuclear Information System (INIS)
This work is about the calculation of thermal conductivity of insulating building materials made from plant particles. To determine the type of raw materials, the particle sizes or the volume fractions of plant and binder, a tool dedicated to calculate the thermal conductivity of heterogeneous materials has been developped, using the discrete element method to generate the volume element and the finite element method to calculate the homogenized properties. A 3D optical scanner has been used to capture plant particle shapes and convert them into a cluster of discret elements. These aggregates are initially randomly distributed but without any overlap, and then fall down in a container due to the gravity force and collide with neighbour particles according to a velocity Verlet algorithm. Once the RVE is built, the geometry is exported in the open-source Salome-Meca platform to be meshed. The calculation of the effective thermal conductivity of the heterogeneous volume is then performed using a homogenization technique, based on an energy method. To validate the numerical tool, thermal conductivity measurements have been performed on sunflower pith aggregates and on packed beds of the same particles. The experimental values have been compared satisfactorily with a batch of numerical simulations.
A finite field method for calculating molecular polarizability tensors for arbitrary multipole rank.
Elking, Dennis M; Perera, Lalith; Duke, Robert; Darden, Thomas; Pedersen, Lee G
2011-11-30
A finite field method for calculating spherical tensor molecular polarizability tensors α(lm;l'm') = ∂Δ(lm)/∂ϕ(l'm')* by numerical derivatives of induced molecular multipole Δ(lm) with respect to gradients of electrostatic potential ϕ(l'm')* is described for arbitrary multipole ranks l and l'. Interconversion formulae for transforming multipole moments and polarizability tensors between spherical and traceless Cartesian tensor conventions are derived. As an example, molecular polarizability tensors up to the hexadecapole-hexadecapole level are calculated for water using the following ab initio methods: Hartree-Fock (HF), Becke three-parameter Lee-Yang-Parr exchange-correlation functional (B3LYP), Møller-Plesset perturbation theory up to second order (MP2), and Coupled Cluster theory with single and double excitations (CCSD). In addition, intermolecular electrostatic and polarization energies calculated by molecular multipoles and polarizability tensors are compared with ab initio reference values calculated by the Reduced Variation Space method for several randomly oriented small molecule dimers separated by a large distance. It is discussed how higher order molecular polarizability tensors can be used as a tool for testing and developing new polarization models for future force fields. PMID:21915883
Advanced calculational methods for power reactors and LWR core design parameters
International Nuclear Information System (INIS)
The purpose of the Specialists Meeting on Advanced Calculational Methods for Power Reactors, held in Cadarache, France, 10-14 September 1990, was to provide a forum for reviewing and discussing selected core physics of water cooled reactors (including high convertors). New methods of advanced calculation for advanced fuels and complex geometries of next generation reactors with a high level of accuracy were discussed and the importance of supercomputing and on-line monitoring was also acknowledged. The meeting was attended by about 60 participants from 20 countries who presented 30 papers. The Technical Committee Meeting on LWR Core Design Parameters, held in Rez, former Czechoslovakia, 7-11 October 1991, provided an opportunity for participants to exchange their experience on reactor physics aspects of benchmark calculations of various lattices, methods for core parameter calculations, core monitoring and in-core fuel management. At the Workshop there were further discussions related to the benchmark problems, homogenization techniques and cross-section representations. Thirty-five papers were presented by about 43 participants from 19 countries. A separate abstract was prepared for each of the mentioned papers. Refs, figs and tabs
Refinement of the sub-structure method for integral transport calculations
International Nuclear Information System (INIS)
A new generalization of the interface-current method for coupling two-dimensional heterogeneous assemblies, called sub-structures, has been developed. The method has been designed for fine-structure burn-up calculations in very heterogeneous media of large size. For the calculations the medium is divided into rectangular sub-structures, which can have internal symmetries, containing rectangular and/or cylindrical structure elements, divided into homogeneous zones. A zone-wise flat or linear expansion is used to formulate a direct collision-probability problem within each sub-structure. The sub-structures are coupled by making a piece-wise uniform or linear expansion for the partial currents entering and leaving the sub-structures. The method has also been used to implement an approximate piece-wise isotropic reflection for two dimensional x-y collision probabilities calculations. The accuracies and computing times achieved are illustrated by one-group fixed source numerical calculations for a typical 7x7 pin PWR assembly as well as for a set of fuel slabs imbedded in water moderator
A CNS calculation line based on a Monte-Carlo method
International Nuclear Information System (INIS)
The neutronic design of the moderator cell of a Cold Neutron Source (CNS) involves many different considerations regarding geometry, location, and materials. The decisions taken in this sense affect not only the neutron flux in the source neighbourhood, which can be evaluated by a standard deterministic method, but also the neutron flux values in experimental positions far away from the neutron source. At long distances from the CNS, very time consuming 3D deterministic methods or Monte Carlo transport methods are necessary in order to get accurate figures of standard and typical magnitudes such as average neutron flux, neutron current, angular flux, and luminosity. The Monte Carlo method is a unique and powerful tool to calculate the transport of neutrons and photons. Its use in a bootstrap scheme appears to be an appropriate solution for this type of systems. The use of MCNP as the main neutronic design tool leads to a fast and reliable method to perform calculations in a relatively short time with low statistical errors, if the proper scheme is applied. The design goal is to evaluate the performance of the CNS, its beam tubes and neutron guides, at specific experimental locations in the reactor hall and in the neutron or experimental hall. In this work, the calculation methodology used to design a CNS and its associated Neutron Beam Transport Systems (NBTS), based on the use of the MCNP code, is presented. (author)
Inverse dispersion method for calculation of complex photonic band diagram and PT symmetry
Rybin, Mikhail V.; Limonov, Mikhail F.
2016-04-01
We suggest an inverse dispersion method for calculating a photonic band diagram for materials with arbitrary frequency-dependent dielectric functions. The method is able to calculate the complex wave vector for a given frequency by solving the eigenvalue problem with a non-Hermitian operator. The analogy with PT -symmetric Hamiltonians reveals that the operator corresponds to the momentum as a physical quantity, and the singularities at the band edges are related to the branch points and responses for the features on the band edges. The method is realized using a plane wave expansion technique for a two-dimensional periodic structure in the case of TE and TM polarizations. We illustrate the applicability of the method by the calculation of the photonic band diagrams of an infinite two-dimensional square lattice composed of dielectric cylinders using the measured frequency-dependent dielectric functions of different materials (amorphous hydrogenated carbon, silicon, and chalcogenide glass). We show that the method allows one to distinguish unambiguously between Bragg and Mie gaps in the spectra.
International Nuclear Information System (INIS)
An improved collision probability method for thermal-neutron-flux calculation in a cylindrical reactor cell has been developed. Expanding the neutron flux and source into a series of even powers of the radius, one' gets a convenient method for integration of the one-energy group integral transport equation. It is shown that it is possible to perform an analytical integration in the x-y plane in one variable and to use the effective Gaussian integration over another one. Choosing a convenient distribution of space points in fuel and moderator the transport matrix calculation and cell reaction rate integration were condensed. On the basis of the proposed method, the computer program DISKRET for the ZUSE-Z 23 K computer has been written. The suitability of the proposed method for the calculation of the thermal-neutron-flux distribution in a reactor cell can be seen from the test results obtained. Compared with the other collision probability methods, the proposed treatment excels with a mathematical simplicity and a faster convergence. (author)
Leal, Allan; Saar, Martin
2016-04-01
Computational methods for geochemical and reactive transport modeling are essential for the understanding of many natural and industrial processes. Most of these processes involve several phases and components, and quite often requires chemical equilibrium and kinetics calculations. We present an overview of novel methods for multiphase equilibrium calculations, based on both the Gibbs energy minimization (GEM) approach and on the solution of the law of mass-action (LMA) equations. We also employ kinetics calculations, assuming partial equilibrium (e.g., fluid species in equilibrium while minerals are in disequilibrium) using automatic time stepping to improve simulation efficiency and robustness. These methods are developed specifically for applications that are computationally expensive, such as reactive transport simulations. We show how efficient the new methods are, compared to other algorithms, and how easy it is to use them for geochemical modeling via a simple script language. All methods are available in Reaktoro, a unified open-source framework for modeling chemically reactive systems, which we also briefly describe.
Determination of the size of a radiation source by the method of calculation of diffraction patterns
Tilikin, I. N.; Shelkovenko, T. A.; Pikuz, S. A.; Hammer, D. A.
2013-07-01
In traditional X-ray radiography, which has been used for various purposes since the discovery of X-ray radiation, the shadow image of an object under study is constructed based on the difference in the absorption of the X-ray radiation by different parts of the object. The main method that ensures a high spatial resolution is the method of point projection X-ray radiography, i.e., radiography from a point and bright radiation source. For projection radiography, the small size of the source is the most important characteristic of the source, which mainly determines the spatial resolution of the method. In this work, as a point source of soft X-ray radiation for radiography with a high spatial and temporal resolution, radiation from a hot spot of X-pinches is used. The size of the radiation source in different setups and configurations can be different. For four different high-current generators, we have calculated the sizes of sources of soft X-ray radiation from X-ray patterns of corresponding objects using Fresnel-Kirchhoff integrals. Our calculations show that the size of the source is in the range 0.7-2.8 μm. The method of the determination of the size of a radiation source from calculations of Fresnel-Kirchhoff integrals makes it possible to determine the size with an accuracy that exceeds the diffraction limit, which frequently restricts the resolution of standard methods.
A new method to calculate the time delay of the Pi2 pulsations
Ghamry, Essam; Fathy, Adel
2016-01-01
The time delay determination of the Pi2 pulsations could provide more understanding of the propagation characteristics of the Pi2. Few studies have concerned with the time delay of Pi2 pulsation. We present a new method to calculate the time delay of Pi2 pulsations using cross wavelet technique. We study 48 events occurred in March 2008 and February-May 2009 at Carson City (CCNV), McGrath (MCGR), The Pas (TPAS) and Kuujjuarapik (KUUJ) stations which belong to the ground magnetometer network of the Time History of Events and Macroscale Interactions during Substorms (THEMIS). The cross wavelet spectrum showed a comparable time with that obtained using cross correlation method. We suggest that the cross wavelet technique can be effectively used to calculate the time delay of Pi2 pulsation and further used as a substitute for cross correlation method.
Pavanello, Michele; Visscher, Lucas; Neugebauer, Johannes
2012-01-01
Quantum--Mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those charge transfer excitations that take place between non-covalently bound molecules. In particular, we present a method that scales linearly with the number of non-covalently bound molecules in the system and is based on a two-pronged approach: The molecular electronic structure of broken-symmetry charge-localized states is obtained with the Frozen Density Embedding formulation of subsystem Density-Functional Theory; subsequently, in a post-SCF calculation, the full-electron Hamiltonian and overlap matrix elements among the charge-localized states are evaluated with an algorithm which takes full advantage of the subsystem DFT density partitioning technique. The method is benchmarked against Coupled-Cluster calculations and achieves chemical accuracy for the systems considered...
Calculation of gamma ray buildup factors for a very thick slab with angular eigenvalue method
International Nuclear Information System (INIS)
The buildup factors of gamma rays are still widely used in the practical shielding calculations. Although the early compilation of buildup factors was published back to 50's, it is still a tedious, though straightforward, task even for state-of-the-art computers. The most recent database of buildup factors covers the distance up to 40 mean free paths. The angular eigenvalue method, which was proposed by one of the author (A.S.) to calculate the transmission of gamma rays through a homogeneous slab, is based fundamentally on the invariant embedding method. This method has been applied to obtain the gamma ray buildup factors in homogeneous medium. It was found that the buildup factors were easily obtained for the distance over 40 mean free paths. (author)
Fu, L.; Zhong, W. Y.; Qiao, H. H.; Liu, G. X.; Qian, H. L.
2015-07-01
The methods of ideal reflector surface, two-parameter, five-parameter, and six-parameter best-fit paraboloid are presented in this paper. Based on these methods, the adjustment values of gravity deformations are calculated for the main reflector of large-scale Cassegrain antenna. Accordingly, the positions of subreflector are corrected, and the effects of offset-focus on electric performance are also analyzed. Taking Shanghai 65 m antenna as a research object, the adjustment values of actuator and hexapod, the accuracy of the main reflector surface, and the pointing error after offsetting the focus are contrasted. As a result, the method of six-parameter best-fit paraboloid is ideal to calculate active control value for antenna panels after the effects of feed defocus have been adjusted and modified. The results offer data for the active control of antenna.
The new high resolution method of Godunov`s type for 3D viscous flow calculations
Energy Technology Data Exchange (ETDEWEB)
Yershov, S.V.; Rusanov, A.V. [Ukranian National Academy of Sciences, Kahrkov (Ukraine)
1996-12-31
The numerical method is suggested for the calculations of the 3D viscous compressible flows described by the thin-layer Reynolds-averaged Navier-Stokes equations. The method is based on the Godunov`s finite-difference scheme and it uses the ENO reconstruction suggested by Harten to achieve the uniformly high-order accuracy. The computational efficiency is provided with the simplified multi grid approach and the implicit step written in {delta} -form. The turbulent effects are simulated with the Baldwin - Lomax turbulence model. The application package FlowER is developed to calculate the 3D turbulent flows within complex-shape channels. The numerical results for the 3D flow around a cylinder and through the complex-shaped channels show the accuracy and the reliability of the suggested method. (author)
A general, efficient and robust method to calculate free energy difference between systems
Farhi, Asaf
2013-01-01
Calculating free energy differences is a topic of substantial interest and has many applications including molecular docking and hydration, solvation, and binding free energies which is used in computational drug discovery. However, in equilibrium methods the compared molecules are required to have large phase space overlap, which is usually not satisfied for two random systems, and there remain the challenges of robustness and automation. Here a highly efficient and robust method, that enables a wide range of comparisons, will be introduced, demonstrated and compared. In this method instead of transforming between one system into the other to perform the calculation each system is transformed into its replica with the different long range energy terms relaxed, which is inherently correlated with the original one, in order to eliminate the partition function difference arising from these terms. Then, since each transformed system can be treated as non interacting systems, the remaining difference in the (orig...
Li, Yongxiu; Zhang, Saiqun; Zhang, John Z. H.; He, Xiao
2016-05-01
Accurate description of the conformational energies of the amino acids is essential for molecular dynamics simulation of protein structures. In this study, we compute the relative energies at 51 conformations for a trialanine tetrapeptide at different levels of theory. The computed energies at various theoretical levels, including the semiempirical DFTB method, HF, DFT, MP2 and CCSD(T), are compared with each other. The calculated energies from density-fitting local CCSD(T)/CBS (complete basis set) calculations are taken as the benchmark. The accuracy of the theoretical methods is highly dependent on the electronic correlation and dispersion corrections as well as the size of the basis sets. The involvement of the empirical dispersion energies in HF and DFT methods consistently improves their performance. Considering both the accuracy and computational efficiency, the Minnesota density functional M06-L-D and M06-2X-D are efficient and accurate for modeling of trialanine structures.
Accurate calculation of computer-generated holograms using angular-spectrum layer-oriented method.
Zhao, Yan; Cao, Liangcai; Zhang, Hao; Kong, Dezhao; Jin, Guofan
2015-10-01
Fast calculation and correct depth cue are crucial issues in the calculation of computer-generated hologram (CGH) for high quality three-dimensional (3-D) display. An angular-spectrum based algorithm for layer-oriented CGH is proposed. Angular spectra from each layer are synthesized as a layer-corresponded sub-hologram based on the fast Fourier transform without paraxial approximation. The proposed method can avoid the huge computational cost of the point-oriented method and yield accurate predictions of the whole diffracted field compared with other layer-oriented methods. CGHs of versatile formats of 3-D digital scenes, including computed tomography and 3-D digital models, are demonstrated with precise depth performance and advanced image quality. PMID:26480062
Improvement of flux distribution calculation using the extrapolation method of Richardson
International Nuclear Information System (INIS)
Richardson have advanced a method for increasing the accuracy in numerical solving of linear differential equations. So, he proposed several schemes for performing algorythms, in which various approximtion parameters are used. It has been proved that a linear combination of this solution under certain circumstances gives a higher accuracy. Starting from these facts the present paper descpibes the application of the Richardson's method in improving the neutron flux calculation by using the EXTERMINATOR-2-INPR code. The considered benchmark problem has been conceived by D.R.Vondy from ORNL-USA. It consists of solving the multigroup diffusion equations for homogeneous two-dimensional slab. The results obtained show the efficiency of the Richardson method in improving the neutron flux calculation and constitutes a basis for achieving algorythms for other categories of problems. (authors)