Institute of Scientific and Technical Information of China (English)
YAN Rui; CHEN Yong; GAO Fu-wang; HUANG Fu-qiong
2008-01-01
Based on linear poroelastic theory of ideal poroelastic media, we apply the mathematic expression between pore pressure and volume strain for well-aquifer system to analyzing the observed data of water level and volume strain changes aroused by Sumatra Ms8.7 (determined by China Seismic Networks Center) seismic waves at Changping, Beijing, station on December 26, 2004 from both time and frequency domain. The response coefficients of water level fluctuation to volume strain are also calculated when seismic waves were passing through confined aquifer. A method for estimating Skempton constant B is put forward, which provide an approach for understanding of the characteristics of aquifer.
Analysis of the chemical equilibrium of combustion at constant volume
Marius BREBENEL
2014-01-01
Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant ...
International Nuclear Information System (INIS)
As of February 3, 1975, 175 neutron group constants had been derived from the Evaluated Nuclear Data Library (ENDL) at LLL. In this volume, tables and graphs of the constants are presented along with the conventions used in their preparation. (U.S.)
Analysis of the chemical equilibrium of combustion at constant volume
Directory of Open Access Journals (Sweden)
Marius BREBENEL
2014-04-01
Full Text Available Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant volume is next considered as example of application, observing the changes occurring in the composition of the combustion gases depending on temperature.
GRUCAL, a computer program for calculating macroscopic group constants
International Nuclear Information System (INIS)
Nuclear reactor calculations require material- and composition-dependent, energy averaged nuclear data to describe the interaction of neutrons with individual isotopes in material compositions of reactor zones. The code GRUCAL calculates these macroscopic group constants for given compositions from the material-dependent data of the group constant library GRUBA. The instructions for calculating group constants are not fixed in the program, but will be read at the actual execution time from a separate instruction file. This allows to accomodate GRUCAL to various problems or different group constant concepts. (orig.)
Osmosis at constant volume. Negative pressure
Zupanovic, Pasko; Brumen, Milan; Fajmut, Ales; Juretic, Davor
2009-01-01
A thermodynamic state of solvent and solution separated with an elastic semipermeable membrane, in the box with a fixed volume, is considered. It is shown that the minimum of the free energy is accompanied by the compression of the solution and tension of the solvent caused by the transfer of solvent molecules into compartment with solution. The tensile state of the solvent is described in terms of negative pressure. It is found that the negative pressure as well as compression pressure is of the order of osmotic pressure given by van't Hoff equation. It is proposed that this mechanism could be responsible for the water uptake in tall trees.
A code to calculate multigroup constants for fast neutron reactor
International Nuclear Information System (INIS)
KQCS-2 code is a new improved version of KQCS code, which was designed to calculate multigroup constants for fast neutron reactor. The changes and improvements on KQCS are described in this paper. (author)
Calculated Atomic Volumes of the Actinide Metals
DEFF Research Database (Denmark)
Skriver, H.; Andersen, O. K.; Johansson, B.
1979-01-01
The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium.......The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium....
Calculation of local elastic constants at a metallic grain boundary
International Nuclear Information System (INIS)
A new atomistic-simulation method for calculating the full local elastic-constant tensor in terms of local stress and local strain for inhomogeneous systems is described. Results of simulations of an isolated high-angle twist grain boundary are presented. A dramatic reduction in resistance to shear parallel to the grain boundary is observed, and its relation to structural disorder is discussed
Benchmark calculations of the shielding constants in the water dimer
Pecul, Magdalena; Lewandowski, Józef; Sadlej, Joanna
2001-01-01
The NMR shielding constants in (H 2O) 2 have been calculated using GIAO-SCF, MP2, MP4 and CCSD methods and for a range of basis sets. According to the obtained results the 6-311++G ** or aug-cc-pVDZ basis sets are recommended for SCF calculations, and the aug-cc-pVXZ series is suggested for correlated calculations of the interaction-induced changes in the shielding constants. The counterpoise correction improves the results towards the basis set limit and is essential in the case of 17O shielding. Correlation effects are substantial for the changes in 17O shielding, less so for 1H shielding. They are overestimated by the MP2 method.
Heating pulse tests under constant volume on natural Boom clay
Lima, Analice; Romero Morales, Enrique Edgar; Gens Solé, Antonio; Muñoz, Juan Jorge; Li, X. L.
2009-01-01
Boom clay formation is a potential natural host rock for geological disposal of High Level Nuclear Waste in Belgium. Heating pulse tests with controlled power supply (maximum temperature was limited to 85ºC) and controlled hydraulic boundary conditions were performed under nearly constant volume conditions to study the impact of thermal loads on this clay formation. Selected test results on impact borehole samples retrieved in horizontal direction are presented and discussed. Attention is foc...
Chemistry of tributyl phosphate and nitric acid at constant volume
International Nuclear Information System (INIS)
This paper addresses the reaction of tributyl phosphate (TBP) with nitric acid (HNO3). The reaction pressure of TBP/HNO3 mixtures as a function of time was measured under constant volume. A simplified model, which parametrically includes autocatalysis, was used to plot the total gas production of the reaction as a function of time. Comparison of the functions shows a rough equivalence in the induction time, reaction time, and total gas production. Predictions of the amounts of reaction products as a function of time were made based on assumptions regarding autocatalysis and using rate constants from experimental data. The derived reaction mechanisms and experimental results have several implications. Tests with a large amount of venting and high surface to volume ratio will show very different behavior than tests with increasing confinement and low surface to volume ratios. The amount alkyl nitrate, carbon monoxide, or hydrogen that reacts within the organic phase is limited by their solubilities and volatilities. The overall yield of both heat and gas per mol of nitric acid or TBP will vary significantly depending on the amount of solution, free volume, and vessel vent capacity
Macroscopic multigroup constants for accelerator driven system core calculation
International Nuclear Information System (INIS)
The high-level wastes stored in facilities above ground or shallow repositories, in close connection with its nuclear power plant, can take almost 106 years before the radiotoxicity became of the order of the background. While the disposal issue is not urgent from a technical viewpoint, it is recognized that extended storage in the facilities is not acceptable since these ones cannot provide sufficient isolation in the long term and neither is it ethical to leave the waste problem to future generations. A technique to diminish this time is to transmute these long-lived elements into short-lived elements. The approach is to use an Accelerator Driven System (ADS), a sub-critical arrangement which uses a Spallation Neutron Source (SNS), after separation the minor actinides and the long-lived fission products (LLFP), to convert them to short-lived isotopes. As an advanced reactor fuel, still today, there is a few data around these type of core systems. In this paper we generate macroscopic multigroup constants for use in calculations of a typical ADS fuel, take into consideration, the ENDF/BVI data file. Four energy groups are chosen to collapse the data from ENDF/B-VI data file by PREPRO code. A typical MOX fuel cell is used to validate the methodology. The results are used to calculate one typical subcritical ADS core. (author)
International Nuclear Information System (INIS)
Maxwell-averaged reaction rates (sigma v-bar) are presented for 24 interactions between 1H, 2H, 3H, 3He, 4He, 6Li, 7Li, 10B, and 11B ions. The reactions rates are calculated by use of the evaluated data of the LLL Evaluated Nuclear Data Library (ENDL). 5 figures, 5 tables
Premixed combustion under electric field in a constant volume chamber
Cha, Min Suk
2012-12-01
The effects of electric fields on outwardly propagating premixed flames in a constant volume chamber were experimentally investigated. An electric plug, subjected to high electrical voltages, was used to generate electric fields inside the chamber. To minimize directional ionic wind effects, alternating current with frequency of 1 kHz was employed. Lean and rich fuel/air mixtures for both methane and propane were tested to investigate various preferential diffusion conditions. As a result, electrically induced instability showing cracked structure on the flame surface could be observed. This cracked structure enhanced flame propagation speed for the initial period of combustion and led to reduction in flame initiation and overall combustion duration times. However, by analyzing pressure data, it was found that overall burning rates are not much affected from the electric field for the pressurized combustion period. The reduction of overall combustion time is less sensitive to equivalence ratio for methane/air mixtures, whereas the results demonstrate pronounced effects on a lean mixture for propane. The improvement of combustion characteristics in lean mixtures will be beneficial to the design of lean burn engines. Two hypothetical mechanisms to explain the electrically induced instability were proposed: 1) ionic wind initiated hydrodynamic instability and 2) thermodiffusive instability through the modification of transport property such as mass diffusivity. © 2012 IEEE.
46 CFR 69.65 - Calculation of volumes.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Calculation of volumes. 69.65 Section 69.65 Shipping... MEASUREMENT OF VESSELS Convention Measurement System § 69.65 Calculation of volumes. (a) Volumes V and Vc used... other calculations which relate to the form of the vessel (such as displacement volumes and center...
International Nuclear Information System (INIS)
A diagnostic method has been developed to interpret the results of basic combustion studies with diesel-like fuels performed in a constant volume reactor originally conceived for cetane number measurements. The main target of the method is to calculate the instantaneous heat release over time from the chamber pressure experimental signal. The method incorporates filtering of the raw data to eliminate the oscillations recorded as a consequence of the location of the pressure sensor. It considers homogeneity of the gaseous mixture (single zone model) and change in its composition due to the combustion process. A semi-empirical heat transfer model was also proposed and its coefficients were fitted from experimental results obtained in the constant volume chamber using diesel fuel. -- Highlights: • A diagnostic model for constant volume reactors has been developed and tested. • Updating the gas composition after combustion improves accuracy of the method. • Heat transfer coefficients are used for the fulfillment of boundary conditions. • The model provides a deeper insight than the apparent heat release analysis
Hashimoto, Hiroyoshi; Kawano, Tomohiko; Momma, Toshiyuki; Uesaka, Katsumi
Ministry of Land, Infrastructure, Transport and Tourism of Japan is going to make maximum use of vehicle detectors installed at national roads around the country and efficiently gather traffic volume data from wide areas by estimating traffic volumes within adjacent road sections based on the constant observation data obtained from the vehicle detectors. Efficient processing of outliers and missing values in constant observation data are needed in this process. Focusing on the processing of singular and missing values, the authors have developed a series of algorithms to calculate hourly traffic volumes in which a required accuracy is secured based on measurement data obtained from vehicle detectors. The algorithms have been put to practical uses. The main characteristic of these algorithms is that they use data accumulated in the past as well as data from constant observation devices in adjacent road sections. This paper describes the contents of the developed algorithms and clarifies their accuracy using actual observation data and by making comparis on with other methods.
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
International Nuclear Information System (INIS)
The KIVA code developed at the Los Alamos Scientific Laboratory was used to model the flow and heat transfer in a constant volume bomb. Good agreement was obtained between calculated results and experimental measurements for both the swirl velocity and temperature fields. Correlations are presented which relate the instantaneous Nusselt number and dimensionless decay rate of angular momentum with an instantaneous Reynold's number
Efficiency characteristics of a new quasi-constant volume combustion spark ignition engine
Directory of Open Access Journals (Sweden)
Dorić Jovan Ž.
2013-01-01
Full Text Available A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI engine concept is the realization of quasi-constant volume (QCV during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC engines. These advantages over standard engine are achieved through synthesis of unconventional piston mechanism. The numerical calculation was performed for several cases of different piston mechanism parameters, compression ratio and engine speed. Calculated efficiency and power diagrams are plotted and compared with performance of ordinary SI engine. The results show that combustion during quasi-constant volume has significant impact on improvement of efficiency. The main aim of this paper is to find a proper kinematics parameter of unconventional piston mechanism for most efficient heat addition in SI engines.[Acknowledgment. This research was done as a part of project TR31046 "Improvement of the quality of tractors and mobile systems with the aim of increasing competitiveness and preserving soil and environment", supported by Serbian Ministry of Science and Technological Development.
PHAST, Calculation of isotope equilibrium constants for geochemical models
International Nuclear Information System (INIS)
1 - Description of program or function: The geochemical part of the program has the capability to perform a wide range of chemical reaction calculations that include aqueous complexation, mineral equilibria, surface complexation, ion exchange, solid-solution equilibria, gas-phase equilibration, and general kinetic reactions. In addition, geochemical simulations, which include all of these types of reaction calculations plus mixing, irreversible reactions, and temperature variation, may be used to define initial and chemical boundary conditions for the reaction-transport simulations. Essentially, any modeling capability available in PHREEQC may be used to establish initial and boundary conditions for the reactive-transport simulation of PHAST. All spatially distributed properties are defined by zones that are rectangular prisms. Zones may overlap, in which case the order of definition is important because the last specification of a property for a cell or element will be the one used in the simulation. The units for input of properties may be a mixture of English and SI metric, however, all output data are SI metric with a user-selected time unit. The transport part of PHAST is written in Fortran 90 and the geochemical part is written in C. Both parts dynamically allocate any computer memory necessary for program execution. Little effort has been expended to minimize storage requirements. Consequently, depending on the size of the domain, the program may require relatively large amounts of memory for execution. In the application of PHAST, it is advisable to progress from simple to increasingly complicated simulations. First, the geochemical model PHREEQC should be used to evaluate chemical reactions by the use of reaction-path and then 1D-transport calculations. Second, PHAST should be used in flow-only mode to obtain an acceptable model of the flow system. Finally, PHAST should be used for reaction-transport calculations that combine the flow simulation with
Considerations on the calculation of volumes in two planning systems
International Nuclear Information System (INIS)
The discrepancies in the calculation of the same volume between different planning systems impact on dose-volume histograms and therefore clinical assessment of dosimetry for patients. The transfer, by a local network, tomographic study (CT) and contours of critical organs of patients, between our two planning systems allows us to evaluate the calculation of identical volumes.
Interactions between molecules in screening constants calculations by CHF-GIAO method
International Nuclear Information System (INIS)
Solid ammonia and methyl cyanide has been used as model substances for study of intermolecular effects in screening constants calculation. The NMR gas-to-liquid shift effects have been measured and correlated with theoretical calculations
Elastic constants and thermodynamic properties of Mg2SixSn1-x from first-principles calculations
Institute of Scientific and Technical Information of China (English)
Liu Na-Na; Song Ren-Bo; Du Da-Wei
2009-01-01
This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x (x = 0, 0.25, 0.5, 0.75, 1) compounds by first-principles total energy calculations using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation for the exchange and correlation potential. The elastic constants of Mg2SixSn1-x were calculated. It shows that, at 273 K, the elastic constants of Mg2Si and Mg2Sn are well consistent with previous experimental data. The isotropy decreases with increasing Sn content. The dependences of the elastic constants, the bulk modulus, the shear modulus and the Debye temperatures of Mg2Si and Mg2Si0.5Sn0.5 on pressure were discussed. Through the quasi-harmonic Debye model, in which phononic effects were considered, the specific heat capacities of Mg2SixSn1-x at constant volume and constant pressure were calculated. The calculated specific heat capacities are well consistent with the previous experimental data.
GRUCAL: a program system for the calculation of macroscopic group constants
International Nuclear Information System (INIS)
Nuclear reactor calculations require material- and composition-dependent, energy-averaged neutron physical data in order to decribe the interaction between neutrons and isotopes. The multigroup cross section code GRUCAL calculates these macroscopic group constants for given material compositions from the material-dependent data of the group constant library GRUBA. The instructions for calculating group constants are not fixed in the program, but are read in from an instruction file. This makes it possible to adapt GRUCAL to various problems or different group constant concepts
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…
Calculation Method of Kinetic Constants for the Mathematical Model Peat Pyrolysis
Directory of Open Access Journals (Sweden)
Plakhova Tatyana
2014-01-01
Full Text Available Relevance of the work is related to necessity to simplify the calculation of kinetic constants for the mathematical model peat pyrolysis. Execute transformations of formula Arrhenius law. Degree of conversion is expressed in terms mass changes of sample. The obtained formulas help to calculate the kinetic constants for any type of solid organic fuels
NUMERICAL INTEGRATION IN VOLUME CALCULATION OF IRREGULAR ANTICLINES
Tomislav Malvić; Rajna Rajić; Petra Slavinić; Kristina Novak Zelenika
2014-01-01
The volume of geological structures is often calculated by using the definite integral. Though in some cases the integral can be solved analytically, in practice we usually approximate its value by numerical integration techniques. The application of definite integral in volume calculation is illustrated by two examples. The volume of Mount Fuji, the world-known “conic” geomorphological structure, is calculated by analytical integration. Two basic numerical integration methods, that is, the t...
NUMERICAL INTEGRATION IN VOLUME CALCULATION OF IRREGULAR ANTICLINES
Directory of Open Access Journals (Sweden)
Tomislav Malvić
2014-12-01
Full Text Available The volume of geological structures is often calculated by using the definite integral. Though in some cases the integral can be solved analytically, in practice we usually approximate its value by numerical integration techniques. The application of definite integral in volume calculation is illustrated by two examples. The volume of Mount Fuji, the world-known “conic” geomorphological structure, is calculated by analytical integration. Two basic numerical integration methods, that is, the trapezoidal and Simpson’s rule are applied to subsurface hydrocarbon reservoir volume calculation, where irregular anticline is approximated by a frustum of a right circular cone.
Calculations on the hyperfine constants of the ground states for lithium-like system
Institute of Scientific and Technical Information of China (English)
Wu Xiao-Li; Yu Kai-Zhi; Gou Bing-Cong; Zhang Meng
2007-01-01
In this paper a relativistic many-body perturbation calculation is performed to calculate the hyperfine constants of the ground states for lithium-like isoelectronic sequence. Zeroth-order hyperfine constants are calculated with Dirac-Fock wavefunctions, and the finite basis sets of the Dirac-Fock equations are constructed by B splines. With the finite basis sets, the core polarization and the correlation effect are evaluated.
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.
Developing a program for calculating the volume of earthwork
Žuber, Iztok
2015-01-01
When constructing a facility, earthworks have a great impact on the cost of the project. Calculating the volume of earthwork is therefore a common procedure in the field of Geodesy. Because of the frequency of the procedure it is smart to make it as efficient and automated as possible. This bachelor thesis deals with calculating volumes of excavations and volumes of embankments. The emphasis of the thesis is in the practical case study where we developed a computer program for cal...
Vargas, Francisco M.
2014-01-01
The temperature dependence of the Gibbs energy and important quantities such as Henry's law constants, activity coefficients, and chemical equilibrium constants is usually calculated by using the Gibbs-Helmholtz equation. Although, this is a well-known approach and traditionally covered as part of any physical chemistry course, the required…
Calculation of Henry constant on the base of critical parameters of adsorbable gas
International Nuclear Information System (INIS)
Calculation of Henry constant using correlation between critical parameters Psub(c), Tsub(c) and adsorption energy, determined by the value of internal pressure in molecular field of adsorbent, has been made. The calculated Henry constants for Ar, Kr and Xe, adsorbed by MoS2 and zeolite NaX, are compared with the experimental ones. The state of the molecules adsorbed is evaluated
Small volume of balls, large volume entropy and the Margulis constant
Sabourau, Stéphane
2016-01-01
In his seminal work about bounded cohomology, M. Gromov showed that, under some topological conditions, every closed Riemannian manifold of small volume has large volume entropy. In this article, we strengthen some aspects of this result using an alternative approach. More precisely, we prove that, under some similar, yet different, topological assumptions, every closed Riemannian manifold whose volume of balls is small has large volume entropy. Along the proof of this result, we establish a ...
Teale, Andrew M.; Lutnæs, Ola B.; Helgaker, Trygve; Tozer, David J.; Gauss, Jürgen
2013-01-01
Accurate sets of benchmark nuclear-magnetic-resonance shielding constants and spin-rotation constants are calculated using coupled-cluster singles-doubles (CCSD) theory and coupled-cluster singles-doubles-perturbative-triples [CCSD(T)] theory, in a variety of basis sets consisting of (rotational) London atomic orbitals. The accuracy of the calculated coupled-cluster constants is established by a careful comparison with experimental data, taking into account zero-point vibrational corrections. Coupled-cluster basis-set convergence is analyzed and extrapolation techniques are employed to estimate basis-set-limit quantities, thereby establishing an accurate benchmark data set. Together with the set provided for rotational g-tensors and magnetizabilities in our previous work [O. B. Lutnæs, A. M. Teale, T. Helgaker, D. J. Tozer, K. Ruud, and J. Gauss, J. Chem. Phys. 131, 144104 (2009)], 10.1063/1.3242081, it provides a substantial source of consistently calculated high-accuracy data on second-order magnetic response properties. The utility of this benchmark data set is demonstrated by examining a wide variety of Kohn-Sham exchange-correlation functionals for the calculation of these properties. None of the existing approximate functionals provide an accuracy competitive with that provided by CCSD or CCSD(T) theory. The need for a careful consideration of vibrational effects is clearly illustrated. Finally, the pure coupled-cluster results are compared with the results of Kohn-Sham calculations constrained to give the same electronic density. Routes to future improvements are discussed in light of this comparison.
Effective technique for thermal constants calculation for uranium-water lattices
International Nuclear Information System (INIS)
In paper method of one-group thermal constants calculation for uranium-water lattices is suggested. According to the method neutron thermalization is taken into account without regard for cell multigroup fluxes. Numerical calculations of absorption and fission cross-sections are made for a typical uranium-water lattice with various enrichment and show that method is suitable for use in many variant calculations
Comment on 'The vacuum field energy in a constant volume cavity'
International Nuclear Information System (INIS)
Full text: As a member of the Editorial Board of this journal, I have been urged to respond to an article I have found to be wrong. This is the paper 'The vacuum field energy in a constant volume cavity' by Weigand and Guerra. These authors have investigated the Casimir effect (i.e. the force due to the zero-point energy of the electromagnetic radiation) for a prismatic cavity with perfectly conducting walls. Unfortunately the authors do not seem to have been aware of previous work on this subject, in particular by Lukosz and by Balian and Duplantier. It had been found that in the case of a cavity with wedges, such as a prismatic one, infinite Casimir forces are obtained if the walls are assumed to remain ideal conductors up to arbitrarily high frequencies; for obtaining physically relevant results, it is necessary to take into account that any material becomes transparent to electromagnetic radiations at high enough frequency. The correct Casimir energy has, as its leading term, a contribution proportional to the total length of the wedges. Thus, contrary to the claim, there is no phase transition when the shape of the prismatic cavity is varied. The calculations and results are not valid because the starting point is incorrect. In a cavity of finite volume V the density of modes cannot be approximated by 8πVν2/c3, even cut at the minimum eigenfrequency. The actual density of modes has corrections which are the very source of the Casimir effect. Furthermore, it is necessary to take into account the forces on both sides of the cavity walls. (After having been shown a draft of this Comment, the authors wrote to the Managing Editor that 'the aim of [their] paper is not the calculation of the true Casimir forces'). (author). Letter-to-the-editor
A Calculation Approach to Elastic Constants of Crystallines at High Pressure and Finite Temperature
Institute of Scientific and Technical Information of China (English)
向士凯; 蔡灵仓; 张林; 经福谦
2002-01-01
Elastic constants of Na and Li metals are calculated successfully for temperatures up to 350K and pressures up to 30 GPa using a scheme without involving any adjustable parameter. Elastic constants are assumed to depend only on an effective pair potential that is only determined by the average interatomic distance. Temperature has an effect on elastic constants by way of charging the equilibrium. The elastic constants can be obtained by fitting the relationship between total energy and strain tensor using the new set of lattice parameters obtained by calculating displacement of atoms at the finite temperature and at a fixed pressure. The relationship between the effective pair potential and the interatomic distance is fitted by using a series of data of cohesive energy corresponding to lattice parameters.
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)
Calculation of cell volumes and surface areas in MCNP
International Nuclear Information System (INIS)
MCNP is a general Monte Carlo neutron-photon particle transport code which treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces, and some special fourth-degree surfaces. It is necessary to calculate cell volumes and surface areas so that cell masses, fluxes, and other important information can be determined. The volume/area calculation in MCNP computes cell volumes and surface areas for cells and surfaces rotationally symmetric about any arbitrary axis. 5 figures, 1 table
Buryak, Ilya; Vigasin, Andrey A.
2015-12-01
The present paper aims at deriving classical expressions which permit calculation of the equilibrium constant for weakly interacting molecular pairs using a complete multidimensional potential energy surface. The latter is often available nowadays as a result of the more and more sophisticated and accurate ab initio calculations. The water dimer formation is considered as an example. It is shown that even in case of a rather strongly bound dimer the suggested expression permits obtaining quite reliable estimate for the equilibrium constant. The reliability of our obtained water dimer equilibrium constant is briefly discussed by comparison with the available data based on experimental observations, quantum calculations, and the use of RRHO approximation, provided the latter is restricted to formation of true bound states only.
Energy Technology Data Exchange (ETDEWEB)
Buryak, Ilya; Vigasin, Andrey A., E-mail: vigasin@ifaran.ru [Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, 3 Pyzhevsky per., 119017 Moscow (Russian Federation)
2015-12-21
The present paper aims at deriving classical expressions which permit calculation of the equilibrium constant for weakly interacting molecular pairs using a complete multidimensional potential energy surface. The latter is often available nowadays as a result of the more and more sophisticated and accurate ab initio calculations. The water dimer formation is considered as an example. It is shown that even in case of a rather strongly bound dimer the suggested expression permits obtaining quite reliable estimate for the equilibrium constant. The reliability of our obtained water dimer equilibrium constant is briefly discussed by comparison with the available data based on experimental observations, quantum calculations, and the use of RRHO approximation, provided the latter is restricted to formation of true bound states only.
Ab Initio Calculation of Rate Constants for Molecule-Surface Reactions with Chemical Accuracy.
Piccini, GiovanniMaria; Alessio, Maristella; Sauer, Joachim
2016-04-18
The ab initio prediction of reaction rate constants for systems with hundreds of atoms with an accuracy that is comparable to experiment is a challenge for computational quantum chemistry. We present a divide-and-conquer strategy that departs from the potential energy surfaces obtained by standard density functional theory with inclusion of dispersion. The energies of the reactant and transition structures are refined by wavefunction-type calculations for the reaction site. Thermal effects and entropies are calculated from vibrational partition functions, and the anharmonic frequencies are calculated separately for each vibrational mode. This method is applied to a key reaction of an industrially relevant catalytic process, the methylation of small alkenes over zeolites. The calculated reaction rate constants (free energies), pre-exponential factors (entropies), and enthalpy barriers show that our computational strategy yields results that agree with experiment within chemical accuracy limits (less than one order of magnitude). PMID:27008460
Elastic Constants of Na and K from Non-parameter Perturbation Calculation
Institute of Scientific and Technical Information of China (English)
陈军; 经福谦; 陈栋泉; 张景琳; 段素清
2001-01-01
Combining a linear muffin-tin orbital method, which can be used to calculate the total energy and pressure of solids in a self-consistent manner, with a generalized elastic energy equation, a non-parameter perturbation method has been proposed to compute the elastic constant for cubic metals. The pressure dependence of the shear modulus and bulk modulus forNa and K was calculated. It was found that the computed results agree well with experiments.
Quantum Chemical Calculations of EPR-Hyperfine Coupling Constants for Transition Metal Complex
International Nuclear Information System (INIS)
In this this study the performance of various density functional approaches for calculation of electron paramagnetic resonance hyperfine coupling constants in transition metal complexes was studied. Several gradient-corrected as well as hybrid functionals have been validated by comparison with experimental data and high-level coupled-cluster calculation for 21 systems, representing a variety of bonding situations. Second part of this work represents an analysis and interpretation of spin-polarization effects in first transition metal complexes
Accommodating volume-constant age-dependent optical (AVOCADO) model of the crystalline GRIN lens.
Sheil, Conor J; Goncharov, Alexander V
2016-05-01
The purpose of this manuscript is to introduce a new age-dependent model of the human lens with two GRIN power distributions (axial and radial) that allow decoupling of its refractive power and axial optical path length. The aspect ratio of the lens core can be held constant under accommodation, as well as the lens volume by varying the asphericity of the lens external surfaces. The spherical aberration calculated by exact raytracing is shown to be in line with experimental data. The proposed model is compared to previous GRIN models from the literature, and it is concluded that the features of the new model will be useful for GRIN reconstruction in future experimental studies; in particular, studies of the accommodation-dependent properties of the ageing human eye. A proposed logarithmic model of the lens core enables decoupling of three fundamental optical characteristics of the lens, namely axial optical path length, optical power and third-order spherical aberration, without changing the external shape of the lens. Conversely, the near-surface GRIN structure conforms to the external shape of the lens, which is necessary for accommodation modelling. PMID:27231637
Calculation of the connective constant for self-avoiding walks via the pivot algorithm
Clisby, Nathan
2013-01-01
We calculate the connective constant for self-avoiding walks on the simple cubic lattice to unprecedented accuracy, using a novel application of the pivot algorithm. We estimate that \\mu = 4.684 039 931(27). Our method also provides accurate estimates of the number of self-avoiding walks, even for walks with millions of steps.
Calculating the Thermal Rate Constant with Exponential Speed-Up on a Quantum Computer
Lidar, D A; Lidar, Daniel A.; Wang, Haobin
1999-01-01
It is shown how to formulate the ubiquitous quantum chemistry problem of calculating the thermal rate constant on a quantum computer. The resulting exact algorithm scales exponentially faster with the dimensionality of the system than all known ``classical'' algorithms for this problem.
International Nuclear Information System (INIS)
Temperature-dependent elastic stiffness constants (cijs), including both the isothermal and isoentropic ones, have been predicted for rhombohedral α-Al2O3 and monoclinic θ-Al2O3 in terms of a quasistatic approach, i.e., a combination of volume-dependent cijs determined by a first-principles strain versus stress method and direction-dependent thermal expansions obtained by first-principles phonon calculations. A good agreement is observed between the predictions and the available experiments for α-Al2O3, especially for the off-diagonal elastic constants. In addition, the temperature-dependent cijs predicted herein, in particular the ones for metastable θ-Al2O3, enable the stress analysis at elevated temperatures in thermally grown oxides containing α- and θ-Al2O3, which are crucial to understand the failure of thermal barrier coatings in gas-turbine engines.
Energy Technology Data Exchange (ETDEWEB)
Elsharkawy, A.M.; Foda, S.G. [Kuwait University, Safat (Kuwait). Petroleum Engineering Dept.
1998-03-01
Currently, two approaches are being used to predict the changes in retrograde gas condensate composition and estimate the pressure depletion behavior of gas condensate reservoirs. The first approach uses the equation of states whereas the second uses empirical correlations. Equations of states (EOS) are poor predictive tools for complex hydrocarbon systems. The EOS needs adjustment against phase behavior data of reservoir fluid of known composition. The empirical correlation does not involve numerous numerical computations but their accuracy is limited. This study presents two general regression neural network (GRNN) models. The first model, GRNNM1, is developed to predict dew point pressure and gas compressibility at dew point using initial composition of numerous samples while the second model, GRNNM2, is developed to predict the changes in well stream effluent composition at any stages of pressure depletion. GRNNM2 can also be used to determine the initial reservoir fluid composition using dew point pressure, gas compressibility at dew point, and reservoir temperature. These models are based on analysis of 142 sample of laboratory studies of constant volume depletion (CVD) for gas condensate systems forming a total of 1082 depletion stages. The database represents a wide range of gas condensate systems obtained worldwide. The performance of the GRNN models has been compared to simulation results of the equation of state. The study shows that the proposed general regression neural network models are accurate, valid, and reliable. These models can be used to forecast CVD data needed for many reservoir engineering calculations in case laboratory data is unavailable. The GRNN models save computer time involved in EOS calculations. The study also show that once these models are properly trained they can be used to cut expenses of frequent sampling and laborious experimental CVD tests required for gas condensate reservoirs. 55 refs., 13 figs., 6 tabs.
Dzuba, V. A.; Flambaum, V. V.
A brief review of the search for variation of the fine structure constant in quasar absorption spectra is presented. Special consideration is given to the role of atomic calculations in the analysis of the observed data. A range of methods which allow to perform calculations for atoms or ions with different electron structure and which cover practically all periodic table of elements is discussed. Critical compilation of the results of the calculations as well as a review of the most recent results of the analysis are presented.
Dzuba, V A
2008-01-01
A brief review of the search for variation of the fine structure constant in quasar absorption spectra is presented. Special consideration is given to the role of atomic calculations in the analysis of the observed data. A range of methods which allow to perform calculations for atoms or ions with different electron structure and which cover practically all periodic table of elements is discussed. Critical compilation of the results of the calculations as well as a review of the most recent results of the analysis are presented.
A simple van’t Hoff law for calculating Langmuir constants in clathrate hydrates
International Nuclear Information System (INIS)
Highlights: • Tabulated Langmuir constants of simple gas hydrates for several molecules. • A van’t Hoff law in the 50–300 K temperature range is given for each case. • Practical form of van’t Hoff parameters for planetologists. • Fractional occupancies of guest species can be easily calculated. • An anisotropic guest-water atom–atom potential is used for numerical calculations. - Abstract: This work gives a van’t Hoff law expression of Langmuir constants of different species for determining their occupancy in clathrate hydrates. First, a pairwise site–site interaction potential energy model is used to calculate the Langmuir constants in an otherwise anisotropic potential environment, as a function of temperature. The results are then fitted to a van’t Hoff law expression to give a set of parameters that can be used for calculating clathrates compositions. The van’t Hoff law’s parameters are given for eighteen gas species trapped in the small and large cavities of structure types I and II. The accuracy of this approach is based on a detailed comparison with available experimental and/or previously calculated data for ethane, cyclo-propane, methane and carbon dioxide clathrate hydrates. A comparison with the analytical cell method is also carried out to better understand the importance of asymmetry and possible limitations of the van’t Hoff temperature dependence
Sicilia, E.; de Luca, G.; Chiodo, S.; Russo, N.; Calaminici, P.; Koster, A. M.; Jug, K.
Density functional calculations of the electric field gradient tensor at the nitrogen nucleus in 13 test molecules, containing 14 nitrogen sites, have been performed using the linear combination of Gaussian-type orbital Kohn-Sham density functional theory (LCGTO-KSDFT) approach. Local and gradient corrected functionals were used for all-electron calculations. All the molecular structures were optimized at their respective levels of theory with extended basis sets. Calibrated 14N nuclear quadrupole moments were obtained through a fitting procedure between calculated electric field gradients and experimental nuclear quadrupole coupling constants of the test set of molecules for each basis set and functional considered. With these calibrated 14N nuclear quadrupole moments, the nuclear quadrupole coupling constants of the following selected systems were determined: fluoromethylisonitrile, pyridine, pyrrole, imadazole, pyrazole, 1,8-bis(dimethyl-amino)naphthalene, cyclotetramethylenetetranitramine, cocaine and heroin.
Calculation of nuclear spin-spin coupling constants using frozen density embedding
International Nuclear Information System (INIS)
We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between 199Hg and 13C upon coordination of dimethylsulfoxide solvent molecules
Calculation of nuclear spin-spin coupling constants using frozen density embedding
Energy Technology Data Exchange (ETDEWEB)
Götz, Andreas W., E-mail: agoetz@sdsc.edu [San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Dr MC 0505, La Jolla, California 92093-0505 (United States); Autschbach, Jochen [Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000 (United States); Visscher, Lucas, E-mail: visscher@chem.vu.nl [Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, Theoretical Chemistry, De Boelelaan 1083, 1081 HV Amsterdam (Netherlands)
2014-03-14
We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between {sup 199}Hg and {sup 13}C upon coordination of dimethylsulfoxide solvent molecules.
Calculation of nuclear spin-spin coupling constants using frozen density embedding
Götz, Andreas W.; Autschbach, Jochen; Visscher, Lucas
2014-03-01
We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between 199Hg and 13C upon coordination of dimethylsulfoxide solvent molecules.
Calculation of the connective constant for self-avoiding walks via the pivot algorithm
Clisby, Nathan
2013-06-01
We calculate the connective constant for self-avoiding walks on the simple cubic lattice to unprecedented accuracy, using a novel application of the pivot algorithm. We estimate that μ = 4.684 039 931 ± 0.000 000 027. Our method also provides accurate estimates of the number of self-avoiding walks, even for walks with millions of steps.
Calculation of the connective constant for self-avoiding walks via the pivot algorithm
International Nuclear Information System (INIS)
We calculate the connective constant for self-avoiding walks on the simple cubic lattice to unprecedented accuracy, using a novel application of the pivot algorithm. We estimate that μ = 4.684 039 931 ± 0.000 000 027. Our method also provides accurate estimates of the number of self-avoiding walks, even for walks with millions of steps. (paper)
Lima, Analice; Romero Morales, Enrique Edgar; Vaunat, Jean; Gens Solé, Antonio; Li, X. L.
2009-01-01
Boom clay is a potential geological host formation for High Level Nuclear Waste in Belgium. Impact of thermal loads may play an important role on this clay formation. To this aim, heating pulse tests on intact borehole samples were carried out using an axi-symmetric heating cell. Heating tests under nearly constant volume conditions and different target temperatures (maximum 85°C) were performed under controlled hydraulic boundary conditions. Selected test result are presented and afterwards ...
Efficiency characteristics of a new quasi-constant volume combustion spark ignition engine
Dorić Jovan Ž.; Klinar Ivan J.
2013-01-01
A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI) engine concept is the realization of quasi-constant volume (QCV) during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC) engines. These advantages over standard engine are achieved through sy...
Rusakova, I. L.; Rusakov, Yu Yu; Krivdin, L. B.
2016-04-01
The theoretical grounds of the modern relativistic methods for quantum chemical calculation of spin–spin coupling constants in nuclear magnetic resonance spectra are considered. Examples and prospects of application of relativistic calculations of these constants in the structural studies of organic and heteroorganic compounds are discussed. Practical recommendations on relativistic calculations of spin–spin coupling constants using the available software are given. The bibliography includes 622 references.
Quantum Monte Carlo calculations of two neutrons in finite volume
Klos, P; Tews, I; Gandolfi, S; Gezerlis, A; Hammer, H -W; Hoferichter, M; Schwenk, A
2016-01-01
Ab initio calculations provide direct access to the properties of pure neutron systems that are challenging to study experimentally. In addition to their importance for fundamental physics, their properties are required as input for effective field theories of the strong interaction. In this work, we perform auxiliary-field diffusion Monte Carlo calculations of the ground and first excited state of two neutrons in a finite box, considering a simple contact potential as well as chiral effective field theory interactions. We compare the results against exact diagonalizations and present a detailed analysis of the finite-volume effects, whose understanding is crucial for determining observables from the calculated energies. Using the L\\"uscher formula, we extract the low-energy S-wave scattering parameters from ground- and excited-state energies for different box sizes.
Calculations on the Fundamental Time-Decay Constant of Water and Polyethylene
International Nuclear Information System (INIS)
The computed time-decay spectrum of the Nelkin, GIN, and MR scattering kernels for water are compared. The spectrum for the Nelkin and GIN kernels were found to be nearly the same. However, the two discrete higher time eigenvalues of the MR kernel, which is in closer agreement with the experimental data on the partial-differential cross-section, are more closely spaced and smaller m magnitude than the corresponding eigenvalues for the other two kernels. In addition, the limit of the discrete spectrum as given by (vΣS)min is approximately 0.22 μsec-1 for the MR kernel and 0.32 μsec-1 for the other scattering kernels. Deviations of less than one percent were found between the calculated and experimental results for the fundamental time-decay constant of water in spherical geometry. The experiments were done by Gon, who made measurements on various-sized systems with bucklings ranging from 0.09 to approximately 3.0 cm-2. The magnitude of the computed fundamental time-decay constant was found not to be particularly sensitive to the kernel used. Comparisons of the calculated and experimentally observed fundamental time-decay constant for polyethylene in cylindrical geometry were also made. For bucklings less than 0.15 cm-2, deviations of less than one percent were noted. For larger bucklings, deviations of approximately two percent were found,except for the largest buckling of approximately 1.5 cm-2 which deviated by six percent. The McMurry scattering kernel was used in the computations on polyethylene. (author)
Efficient Error Calculation for Multiresolution Texture-Based Volume Visualization
Energy Technology Data Exchange (ETDEWEB)
LaMar, E; Hamann, B; Joy, K I
2001-10-16
Multiresolution texture-based volume visualization is an excellent technique to enable interactive rendering of massive data sets. Interactive manipulation of a transfer function is necessary for proper exploration of a data set. However, multiresolution techniques require assessing the accuracy of the resulting images, and re-computing the error after each change in a transfer function is very expensive. They extend their existing multiresolution volume visualization method by introducing a method for accelerating error calculations for multiresolution volume approximations. Computing the error for an approximation requires adding individual error terms. One error value must be computed once for each original voxel and its corresponding approximating voxel. For byte data, i.e., data sets where integer function values between 0 and 255 are given, they observe that the set of error pairs can be quite large, yet the set of unique error pairs is small. instead of evaluating the error function for each original voxel, they construct a table of the unique combinations and the number of their occurrences. To evaluate the error, they add the products of the error function for each unique error pair and the frequency of each error pair. This approach dramatically reduces the amount of computation time involved and allows them to re-compute the error associated with a new transfer function quickly.
First principles calculations of the structure and elastic constants of α, β and γ uranium
International Nuclear Information System (INIS)
This study analyzes structural and elastic properties of five uranium crystal structures: the face centered orthorhombic A20 (α phase), the tetragonal D8b (β phase), body centered tetragonal (bct), body centered cubic (γ phase) and face centered cubic structures. Calculations are performed within the density functional theory framework employing the Projector Augmented Wave method and the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE–GGA) of the exchange correlation. The elastic constants are used to compute polycrystalline elastic moduli, Poisson’s ratio and the Debye temperature for all five structures. The α and γ phase properties are compared with theoretical and experimental results. The complex tetragonal 30 atom beta phase is examined in detail. Representation of the β phase by a bct structure is examined; we find that the structure of the β phase is significantly different from the bct phase but exhibits similar elastic properties. This is the first comprehensive investigation into the elastic constants of uranium utilizing the PBE–GGA
A lattice calculation of the decay constants of heavy-light pseudoscalars
International Nuclear Information System (INIS)
A lattice calculation of the decay constants for D and B mesons is described. Results are obtained (in the quenched approximation) from wall-source lattices in Coulomb gauge at β = 6.3, through a procedure that interpolates smoothly between the static approximation of Eichten and the conventional (''heavy'' Wilson fermion) method. The previously observed discrepancy between these two approaches has been understood, and we discuss the resolution and its limitations. We find fD = 206(9) ± 37 MeV, fDs = 231(7) ± 39 MeV, fB = 179(10) ± 39 MeV, and fBs = 203(8) ± 42 MeV. The first error in each result is statistical, resulting from the jackknife procedure applied to the full analysis. The second is our estimate of systematic errors due to scale-breaking, axial current renormalization, and fitting or extrapolation uncertainties
Calculations of the indirect nuclear spin-spin coupling constants of PbH_{4}
DEFF Research Database (Denmark)
Kirpekar, Sheela; Sauer, Stephan P. A.
1999-01-01
approximation and the second-order polarization propagator approximation with coupled-cluster singles and doubles amplitudes. The effects of nuclear motion were investigated by calculating the coupling constants as a function of the totally symmetric stretching coordinate. We find that the Fermi contact term......We report ab initio calculations of the indirect nuclear spin-spin coupling constants of PbH4 using a basis set which was specially optimized for correlated calculations of spin-spin coupling constants. All nonrelativistic contributions and the most important part of the spin-orbit correction were...
Grenev, I. V.; Gavrilov, V. Yu.
2014-01-01
Adsorption isotherms of molecular hydrogen are measured at 77 K in a series of AlPO alumophosphate zeolites with different microchannel sizes. The potential of the intermolecular interaction of H2 is calculated within the model of a cylindrical channel of variable size. Henry constants are calculated for this model for arbitrary orientations of the adsorbate molecules in microchannels. The experimental and calculated values of the Henry adsorption constant of H2 are compared at 77 K on AlPO zeolites. The constants of intermolecular interaction are determined for the H2-AlPO system.
Quantum chemical and conventional TST calculations of rate constants for the OH + alkane reaction
International Nuclear Information System (INIS)
Reactions of OH with methane, ethane, propane, i-butane, and n-butane have been modeled using ab initio (MP2) and hybrid DFT (BHandHLYP) methods, and the 6-311G(d,p) basis set. Furthermore, single-point calculations at the CCSD(T) level were carried out at the optimized geometries. The rate constants have been calculated using the conventional transition-state theory (CTST). Arrhenius equations are proposed in the temperature range of 250-650 K. Hindered Internal Rotation partition functions calculations were explicitly carried out and included in the total partition functions. These corrections showed to be relevant in the determination of the pre-exponential parameters, although not so important as in the NO3 + alkane reactions [G. Bravo-Perez, J.R. Alvarez-Idaboy, A. Cruz-Torres, M.E. Ruiz, J. Phys. Chem. A 106 (2002) 4645]. The explicit participation of the tunnel effect has been taken into account. The calculated rate coefficients provide a very good agreement with the experimental data. The best agreement for the overall alkane + OH reactions seemed to occur when the BHandHLYP geometries and partition functions are used. For propane and i-butane, in addition to the respective secondary and tertiary H-abstraction channels, the primary one has been considered. These pathways are confirmed to be significant in spite of the large differences in activation energies between primary and secondary or primary and tertiary channels, respectively of propane and i-butane reactions and should not be disregarded
Gas permeation measurement under defined humidity via constant volume/variable pressure method
Jan Roman, Pauls
2012-02-01
Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO 2-separation from flue gas in carbon capture and storage (CCS), or in biogas/natural gas processing. Studying the effect of water vapour on gas permeability through polymeric membranes is essential for materials design and optimization of these membrane applications. In particular, for amine-based CO 2 selective facilitated transport membranes, water vapour is necessary for carrier-complex formation (Matsuyama et al., 1996; Deng and Hägg, 2010; Liu et al., 2008; Shishatskiy et al., 2010) [1-4]. But also conventional polymeric membrane materials can vary their permeation behaviour due to water-induced swelling (Potreck, 2009) [5]. Here we describe a simple approach to gas permeability measurement in the presence of water vapour, in the form of a modified constant volume/variable pressure method (pressure increase method). © 2011 Elsevier B.V.
Zhu, Dongming; Fox, Dennis S.; Miller, Robert A.; Ghosn, Louis J.; Kalluri, Sreeramesh
2004-01-01
The development of advanced high performance constant-volume-combustion-cycle engines (CVCCE) requires robust design of the engine components that are capable of enduring harsh combustion environments under high frequency thermal and mechanical fatigue conditions. In this study, a simulated engine test rig has been established to evaluate thermal fatigue behavior of a candidate engine combustor material, Haynes 188, under superimposed CO2 laser surface impulsive thermal loads (30 to 100 Hz) in conjunction with the mechanical fatigue loads (10 Hz). The mechanical high cycle fatigue (HCF) testing of some laser pre-exposed specimens has also been conducted under a frequency of 100 Hz to determine the laser surface damage effect. The test results have indicated that material surface oxidation and creep-enhanced fatigue is an important mechanism for the surface crack initiation and propagation under the simulated CVCCE engine conditions.
Hall normalization constants for the Bures volumes of the n-state quantum systems
Slater, Paul B.
1999-11-01
We report the results of certain integrations of quantum-theoretic interest, relying, in this regard, upon recently developed parametrizations of Boya et al (1998 Preprint quant-ph/9810084) of the n × n density matrices, in terms of squared components of the unit (n - 1)-sphere and the n × n unitary matrices. Firstly, we express the normalized volume elements of the Bures (minimal monotone) metric for n = 2 and 3, thereby obtaining `Bures prior probability distributions' over the two- and three-state systems. Then, as a first step in extending these results to n>3, we determine that the `Hall normalization constant' (Cn) for the marginal Bures prior probablity distribution over the (n - 1)-dimensional simplex of the n eigenvalues of the n × n density matrices is, for n = 4, equal to 71 680/icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/>2. Since we also find that C3 = 35/icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/>, it follows that C4 is simply equal to 211C3/icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/>. (C2 itself is known to equal 2/icons/Journals/Common/pi" ALT="pi" ALIGN="TOP"/>.) The constant C5 is also found. It too is associated with a remarkably simple decomposition, involving the product of the eight consecutive prime numbers from 3 to 23. We also preliminarily investigate several cases n>5, with the use of quasi-Monte Carlo integration. We hope that the various analyses reported will prove useful in deriving a general formula (which evidence suggests will involve the Bernoulli numbers) for the Hall normalization constant for arbitrary n. This would have diverse applications, including quantum inference and universal quantum coding.
Hall normalization constants for the Bures volumes of the n-state quantum systems
International Nuclear Information System (INIS)
We report the results of certain integrations of quantum-theoretic interest, relying, in this regard, upon recently developed parametrizations of Boya et al (1998 Preprint quant-ph/9810084) of the nxn density matrices, in terms of squared components of the unit (n-1)-sphere and the nxn unitary matrices. Firstly, we express the normalized volume elements of the Bures (minimal monotone) metric for n=2 and 3, thereby obtaining 'Bures prior probability distributions' over the two- and three-state systems. Then, as a first step in extending these results to n>3, we determine that the 'Hall normalization constant' (Cn) for the marginal Bures prior probability distribution over the (n-1)-dimensional simplex of the n eigenvalues of the nxn density matrices is, for n=4, equal to 71 680/π2. Since we also find that C3=35/π, it follows that C4 is simply equal to 211C3/π. (C2 itself is known to equal 2/π.) The constant C5 is also found. It too is associated with a remarkably simple decomposition, involving the product of the eight consecutive prime numbers from 3 to 23. We also preliminarily investigate several cases n>5, with the use of quasi-Monte Carlo integration. We hope that the various analyses reported will prove useful in deriving a general formula (which evidence suggests will involve the Bernoulli numbers) for the Hall normalization constant for arbitrary n. This would have diverse applications, including quantum inference and universal quantum coding. (author)
Energy Technology Data Exchange (ETDEWEB)
Hajlaoui, C., E-mail: hajlaouic@yahoo.fr; Pedesseau, L. [Université Européenne de Bretagne (France); Raouafi, F.; Ben Cheikh Larbi, F. [Université de Carthage, Laboratoire de Physico-Chimie, des Microstructures et des Microsystémes, Institut Préparatoire aux Études Scientifiques et Techniques (Tunisia); Even, J.; Jancu, J.-M. [Université Européenne de Bretagne (France)
2015-08-15
We report first-principle density functional calculations of the spontaneous polarization, piezoelectric stress constants, and elastic constants for the III–V wurtzite structure semiconductors InAs and InP. Using the density functional theory implemented in the VASP code, we obtain polarization values–0.011 and–0.013 C/m{sup 2}, and piezoelectric constants e{sub 33} (e{sub 31}) equal to 0.091 (–0.026) and 0.012 (–0.081) C/m{sup 2} for structurally relaxed InP and InAs respectively. These values are consistently smaller than those of nitrides. Therefore, we predict a smaller built-in electric field in such structures.
Institute of Scientific and Technical Information of China (English)
GAO Ning; LAI Wen-Sheng
2006-01-01
@@ The calculation of elastic constants of Ag/Pd superlattice thin films by molecular dynamics simulations with many-body potentials is presented. It reveals that the elastic constants C11 and C55 increase with decreasing modulation wavelength A of the films, which is consistent with experiments. However, the change of C11 and C55 with A is found to be around the values determined by a rule of mixture using bulk elastic constants of metals.No supermodulus effect is observed and it is due to cancellation between enhanced and reduced contributions to elastic constants from Ag and Pd layers subjected to compressive and tensile strains, respectively.
Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory
International Nuclear Information System (INIS)
The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H12C–12CH–DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated
Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory
Energy Technology Data Exchange (ETDEWEB)
Zuniga-Gutierrez, Bernardo, E-mail: bzuniga.51@gmail.com [Departamento de Ciencias Computacionales, Universidad de Guadalajara, Blvd. Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Camacho-Gonzalez, Monica [Universidad Tecnológica de Tecámac, División A2, Procesos Industriales, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Bendana-Castillo, Alfonso [Universidad Tecnológica de Tecámac, División A3, Tecnologías de la Información y Comunicaciones, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Simon-Bastida, Patricia [Universidad Tecnlógica de Tulancingo, División Electromecánica, Camino a Ahuehuetitla No. 301, Col. Las Presas, C.P. 43642 Tulancingo, Hidalgo (Mexico); Calaminici, Patrizia; Köster, Andreas M. [Departamento de Química, CINVESTAV, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000 (Mexico)
2015-09-14
The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H{sup 12}C–{sup 12}CH–DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated.
DEFF Research Database (Denmark)
Steinmann, Casper; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob
2014-01-01
We present NMR shielding constants obtained through quantum mechanical/molecular mechanical (QM/MM) embedding calculations. Contrary to previous reports, we show that a relatively small QM region is sufficient, provided that a high-quality embedding potential is used. The calculated averaged NMR...
Ab-initio calculation of the pressure dependence of phonons and elastic constants for Al and Li
Vázquez, G.J.; Magaña, L.F.
1988-01-01
We calculated the interionic potentials for aluminium and lithium from first principle pseudopotentials. We constructed these pseudopotentials from the induced electron densities around an aluminium nucleus and around a lithium nucleus respectively. Then we calculated the phonon dispersion curves and the elastic constants. We repeated the whole calculation for several values of pressure by changing, each time, the value of the electron gas density parameter rs. The induced electron densities ...
International Nuclear Information System (INIS)
The temperature dependences of thermal expansion and isothermal compression of (TiGaSe3)0.9(TiInS3)0.1 and (TiGaSe2)0.8(TiInS2)0.2 are investigated. The heat capacity difference at constant pressure and volume is calculated on the base of experimental data. It is established that interactions which are connected with the increase of defect number and weakening of chemical bond in lattice, increases with temperature increase and increase of tiInS2 content in composition
Wolk, Benjamin
2013-07-01
The enhancement of laminar flame development using microwave-assisted spark ignition has been investigated for methane-air mixtures at a range of initial pressures and equivalence ratios in a 1.45. l constant volume combustion chamber. Microwave enhancement was evaluated on the basis of several parameters including flame development time (FDT) (time for 0-10% of total net heat release), flame rise time (FRT) (time for 10-90% of total net heat release), total net heat release, flame kernel growth rate, flame kernel size, and ignitability limit extension. Compared to a capacitive discharge spark, microwave-assisted spark ignition extended the lean and rich ignition limits at all pressures investigated (1.08-7.22. bar). The addition of microwaves to a capacitive discharge spark reduced FDT and increased the flame kernel size for all equivalence ratios tested and resulted in increases in the spatial flame speed for sufficiently lean flames. Flame enhancement is believed to be caused by (1) a non-thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure of the mixture increases, with negligible flame enhancement observed above 3. bar. © 2013 The Combustion Institute.
In situ X-ray diffraction observation of smectite hydration under constant volume
International Nuclear Information System (INIS)
Smectite (especially, montmorillonite) is the major clay mineral constituent of bentonite, which is designed to play a key role as a buffer material in geological repositories for the final disposal of radioactive waste in Japan. It is therefore crucial to understand the hydration behavior of smectite in terms of swelling during hydration and saturation processes. Against such a background, the authors simultaneously observed behaviors of smectite swelling at the micro-level (i.e., both the generation of swelling pressure and the change of hydration state). In the experiments, deionized water was allowed to permeate into a dried specimen of smectite (named Kunipia-F®) with different dry densities (ρd: 0.97, 1.23, 1.43, 1.64 and 1.88 Mg/m3) under conditions of constant temperature and volume. The swelling pressure was measured using an in situ uniaxial consolidation apparatus during the water feeding process. Changes in local hydration states (i.e., one-molecular-layer hydration states to three-molecular-layer hydration states) were also simultaneously observed. Hydration among these different states propagated from the inlet side to the outlet side of the specimen. The authors discussed the relationships governing the hydration state, swelling pressure, the number of hydration moles, dry density, equilibrium final pressure, and then the dynamic mechanism behind pressure propagation. (author)
Non-constant volume exponential solutions in higher-dimensional Lovelock cosmologies
Chirkov, Dmitry; Toporensky, Alexey
2015-01-01
In this paper we propose a scheme which allows one to find all possible exponential solutions of special class -- non-constant volume solutions -- in Lovelock gravity in arbitrary number of dimensions and with arbitrate combinations of Lovelock terms. We apply this scheme to (6+1)- and (7+1)-dimensional flat anisotropic cosmologies in Einstein-Gauss-Bonnet and third-order Lovelock gravity to demonstrate how our scheme does work. In course of this demonstration we derive all possible solutions in (6+1) and (7+1) dimensions and compare solutions and their abundance between cases with different Lovelock terms present. As a special but more "physical" case we consider spaces which allow three-dimensional isotropic subspace for they could be viewed as examples of compactification schemes. Our results suggest that the same solution with three-dimensional isotropic subspace is more "probable" to occur in the model with most possible Lovelock terms taken into account, which could be used as kind of anthropic argument...
Non-constant volume exponential solutions in higher-dimensional Lovelock cosmologies
Chirkov, Dmitry; Pavluchenko, Sergey A.; Toporensky, Alexey
2015-11-01
In this paper we propose a scheme which allows one to find all possible exponential solutions of special class—non-constant volume solutions—in Lovelock gravity in arbitrary number of dimensions and with arbitrate combinations of Lovelock terms. We apply this scheme to (6+1)- and (7+1)-dimensional flat anisotropic cosmologies in Einstein-Gauss-Bonnet and third-order Lovelock gravity to demonstrate how our scheme does work. In course of this demonstration we derive all possible solutions in (6+1) and (7+1) dimensions and compare solutions and their abundance between cases with different Lovelock terms present. As a special but more "physical" case we consider spaces which allow three-dimensional isotropic subspace for they could be viewed as examples of compactification schemes. Our results suggest that the same solution with three-dimensional isotropic subspace is more "probable" to occur in the model with most possible Lovelock terms taken into account, which could be used as kind of anthropic argument for consideration of Lovelock and other higher-order gravity models in multidimensional cosmologies.
International Nuclear Information System (INIS)
The geodesic equations resulting from the Schwarzschild gravitational metric element are solved exactly including the contribution from the cosmological constant. The exact solution is given by genus-2 Siegelsche modular forms. For zero cosmological constant the hyperelliptic curve degenerates into an elliptic curve and the resulting geodesic is solved by the Weierstrass Jacobi modular form. The solution is applied to the precise calculation of the perihelion precession of the orbit of the planet Mercury around the Sun
Mozafari, Elham; Shulumba, Nina; Steneteg, Peter; Alling, Björn; Abrikosov, Igor A.
2016-01-01
We present a theoretical scheme to calculate the elastic constants of magnetic materials in the high-temperature paramagnetic state. Our approach is based on a combination of disordered local moments picture and ab initio molecular dynamics (DLM-MD). Moreover, we investigate a possibility to enhance the efficiency of the simulations using recently introduced method: symmetry imposed force constant temperature dependent effective potential (SIFC-TDEP). We have chosen cubic paramagnetic CrN as ...
Directory of Open Access Journals (Sweden)
Naser Samadi
2013-04-01
Full Text Available In traditional spectrophotometric determination of stability constants of complexation, it is necessary to find a wavelength at which only one of the components has absorbance without any spectroscopic interference of the other reaction components. In the present work, a simple multi-wavelength model-based method has been developed to determine stability constants for complexation reaction regardless of the spectra overlapping of components. Also, pure spectra and concentration profiles of all components are extracted using multi-wavelength model based method. In the present work spectrophotometric titration of several cationic metal ions with new synthetic ligand were studied in order to calculate the formation constant(s. In order to estimate the formation constants a chemometrics method, model based analysis was applied.
Impact of pore-pressure cycling on bentonite in constant volume experiments
International Nuclear Information System (INIS)
Document available in extended abstract form only. The SKB safety case for a KBS-3 repository highlights the potential importance of future successive glaciation events on repository functions. One particular uncertainty is the likely affect of elevated pore-water pressures on barrier safety functions. Over the repository lifetime such changes in pore-water pressure are likely to be cyclic in nature, as successive glacial episodes lead to loading and unloading of the engineered barrier. For a clay-water system with the pore-water in thermodynamic equilibrium with an external reservoir of water at pressure, pw, the total stress acting on the surrounding vessel can be expressed as: (1) σ = Π + αpw where Π is the swelling pressure and α is a proportionality constant. We present results from a series of laboratory experiments designed to investigate this relationship, in the context of glacial loading. Blocks of pre-compacted Mx80 bentonite were manufactured by Clay Technology AB (Lund, Sweden), by rapidly compacting bentonite granules in a mould under a one dimensionally applied stress (Johannesson et al., 1995). The blocks were then sub-sampled and cylindrical specimens prepared for testing (120 mm in length and 60 mm in diameter). The experiments were conducted using a specially designed constant volume cell, which allows the evolution of the total stresses acting on the surrounding vessel to be monitored during clay swelling (at three radial and two axial locations). A high precision syringe pump was used to maintain a constant applied pore pressure within the bentonite, while the rate of hydraulic inflow, and consequent stress development, were monitored to determine the point at which hydraulic equilibrium was reached. During the tests each sample was subjected to an incremental series of constant pore-pressure steps, with all samples experiencing at least one loading and unloading cycle. The resulting average total stress data yield alpha values in the
Hmiel, A.; Winey, J. M.; Gupta, Y. M.; Desjarlais, M. P.
2016-05-01
Accurate theoretical calculations of the nonlinear elastic response of strong solids (e.g., diamond) constitute a fundamental and important scientific need for understanding the response of such materials and for exploring the potential synthesis and design of novel solids. However, without corresponding experimental data, it is difficult to select between predictions from different theoretical methods. Recently the complete set of third-order elastic constants (TOECs) for diamond was determined experimentally, and the validity of various theoretical approaches to calculate the same may now be assessed. We report on the use of density functional theory (DFT) methods to calculate the six third-order elastic constants of diamond. Two different approaches based on homogeneous deformations were used: (1) an energy-strain fitting approach using a prescribed set of deformations, and (2) a longitudinal stress-strain fitting approach using uniaxial compressive strains along the [100], [110], and [111] directions, together with calculated pressure derivatives of the second-order elastic constants. The latter approach provides a direct comparison to the experimental results. The TOECs calculated using the energy-strain approach differ significantly from the measured TOECs. In contrast, calculations using the longitudinal stress-uniaxial strain approach show good agreement with the measured TOECs and match the experimental values significantly better than the TOECs reported in previous theoretical studies. Our results on diamond have demonstrated that, with proper analysis procedures, first-principles calculations can indeed be used to accurately calculate the TOECs of strong solids.
International Nuclear Information System (INIS)
Graphical abstract: The performance of the SOPPA(CC2) method for the calculation of indirect nuclear carbon-carbon spin-spin coupling constants is tested on 197 coupling constants in 41 carbocycles. Research highlights: → Benchmarking of SOPPA(CC2) for carbon-carbon coupling constants in carbocycles. → SOPPA(CC2) scales as SOPPA. → SOPPA(CC2) performs well for indirect carbon-carbon coupling constants. → SOPPA(CC2) gives mean absolute errors of 1.11 Hz relative to experimental values. → SOPPA(CC2) performs better than SOPPA for couplings across more than one bond. - Abstract: We investigate the performance of the newly implemented SOPPA(CC2) method for the calculation of indirect carbon-carbon spin-spin coupling constants. SOPPA(CC2) scales as SOPPA, but has previously been shown to improve the accuracy of spin-spin coupling constants relative to CCSD. We compare the results of SOPPA(CC2) with SOPPA, SOPPA(CCSD), and available experimental values for a wide range of saturated carbocycles (in total 41 carbocycles and 197 coupling constants). It follows that SOPPA(CC2) performs better than SOPPA for couplings across more than one bond, while the two methods performs equally well for the one-bond couplings relatively to SOPPA(CCSD).
Ab Initio Calculations of Elastic Constants of Li2O under Pressure
Institute of Scientific and Technical Information of China (English)
LI Xiao-Feng; CHEN Xiang-Rong; JI Guang-Fu; MENG Chuan-Min
2006-01-01
@@ We investigate the equilibrium lattice constant, bulk modulus, elastic constants and Debye temperature of Li2 O under pressure by using ab initio unrestricted Hartree-Fock (HF) linear combination of atomic orbital (LCAO) periodic approach. The obtained results at zero pressure are well consistent with the available experimental data and other theoretical results. It is found that the elastic constants C11, C12 and C44 and bulk modulus B increase monotonously as pressure increases. Also, the anisotropy will weaken and the Debye temperature will rise with pressure increasing.
A fluctuation method to calculate the third order elastic constants in crystalline solids
Energy Technology Data Exchange (ETDEWEB)
Chen, Zimu [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Qu, Jianmin, E-mail: j-qu@northwestern.edu [Department of Civil and Environmental Engineering, Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208 (United States)
2015-05-28
This paper derives exact expressions of the isothermal third order elastic constants (TOE) in crystalline solids in terms of the kinetic and potential energies of the system. These expressions reveal that the TOE constants consist of a Born component and a relaxation component. The Born component is simply the third derivative of the system's potential energy with respect to the deformation, while the relaxation component is related to the non-uniform rearrangements of the atoms when the system is subject to a macroscopic deformation. Further, based on the general expressions derived here, a direct (fluctuation) method of computing the isothermal TOE constants is developed. Numerical examples of using this fluctuation method are given to compute the TOE constants of single crystal iron.
International Nuclear Information System (INIS)
The ignition and combustion behaviour of vegetable oils to be used as fuel in combustion engines was researched using a constant volume combustion chamber. The chosen vegetable oils were characterised using the two structure indices average number of carbon atoms AC and average number of double bonds ADB. The structure indices were derived from the composition of the analysed fatty acids. The performance of these two structure indices in estimating differences in fuel properties, such as density, net calorific value, elementary composition and surface tension, was shown. The structure indices were also used to explain ignition and combustion behaviour. Differences in ignition and combustion behaviour were primarily recognised in the ignition delay and the first phase of combustion (premixed combustion). No differences were observed between the vegetable oils in subsequent phases of combustion. The longer the ignition delay, the higher the share was of premixed combustion. Models for the prediction of the ignition delay were developed using ADB. The ignition delay rises with increasing ADB. Differences in AC had no significant impact on the ignition delay. Hence, vegetable oils with a high ignition quality are characterised by a low amount of double bonds. The developed models can be used for estimation of the ignition quality and combustion behaviour of unknown vegetable oils. - Highlights: • Ten vegetable oils and two vegetable oil mixtures were tested. • Two suitable structure indices were developed from the fatty acid composition to predict fuel properties. • Differences were detected in the ignition behaviour and in the first combustion phase. • Vegetable oils with short ignition delay are characterised by a low number of double bonds
Witzel, Oliver
2012-01-01
We calculate B-physics quantities using the RBC/UKQCD 2+1 flavor domain-wall plus Iwasaki lattices and the relativistic heavy quark action developed by Christ, Li and Lin. After tuning these parameters nonperturbatively, we present our preliminary results for the calculation of the decay constants f_B and f_{B_s} analyzing data at two lattice spacings of a ~ 0.11 fm and a ~ 0.08 fm.
Nuclear group constant set FUSION-J3 for fusion reactor nuclear calculations based on JENDL-3
International Nuclear Information System (INIS)
Based on evaluated nuclear data file JENDL-3, published in April 1990, we produced a nuclear group constant set 'FUSION-J3' for fusion reactor nuclear calculation by ANISN code instead of GICX40 produced in 1977. The set FUSION-J3 is the coupled group constant set with neutron 125 and gamma-ray 40 group structure, and has the maximum order of 5 as Legendre expansion in scattering cross section. Forty nuclides included in FUSION-J3 can be used in fusion reactor nuclear calculations. Considering mobility in two-dimensional calculations and fixed group structure in induced activity calculation code system as the GICX40 structure, we composed also FUSION-40 group constant set with neutron 42 group and gamma-ray 21 group structure. The set FUSION-40 includes the same maximum order of the Legendre expansion and the same nuclides as FUSION-J3. From the results in experimental analysis and benchmark calculations, it became proved that JENDL-3 is at higher level of accuracy than ENDF/B-IV and -V. The set FUSION-J3 can be clear applicable to fusion reactor nuclear calculations. (author)
Directory of Open Access Journals (Sweden)
Chufeng Hu
2014-01-01
Full Text Available The morphology of vegetation greatly impacts propagation of polarized electromagnetic wave. In order to validate this phenomenon, the mathematical relation between the differential propagation constant of forest vegetation and of its polarized echo is quantitatively derived by using backscattering power profile. The fluctuation of differential propagation constant with frequency is analyzed by combining the morphological characteristics of vegetation. The accurate copolarized data of 3–10 GHz frequency-domain of small trees are obtained by indoor wideband polarimetric measurement system. The results show that morphological characteristics of vegetation at different frequencies can be obtained by the differential propagation constant of polarized electromagnetic wave. At low frequencies, the plants with structural features presented oriented distribution. However, the plants show random distribution of the echoes at higher frequencies, which is mainly from the canopy. The research provides important information to choose the coherence models employed in the parameters retrieval of vegetations.
International Nuclear Information System (INIS)
In multigroup calculations of reactivity and sensitivity coefficients, methodical errors can appear if the interdependence of multigroup constants is not taken into account. For this effect to be taken into account, so-called implicit components of the aforementioned values are introduced. A simple technique for computing these values is proposed. It is based on the use of subgroup parameters.
On the calculation of resonances by means of analytic continuation in coupling constant
Czech Academy of Sciences Publication Activity Database
Horáček, J.; Paidarová, Ivana
2010-01-01
Roč. 257, č. 1 (2010), 012002. E-ISSN 1742-6596 R&D Projects: GA MŠk(CZ) LC06014; GA MŠk OC09079 Institutional research plan: CEZ:AV0Z40400503 Keywords : electron collisions * Dissociation * coupling constant Subject RIV: CF - Physical ; Theoretical Chemistry
Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber
International Nuclear Information System (INIS)
This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O2 concentrations were used, spanning 10–21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH∗ with the increase of ambient temperature and O2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O2 concentration conditions by the
Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber
Jing, Wei
2015-01-01
This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O2 concentrations were used, spanning 10-21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH∗ with the increase of ambient temperature and O2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O2 concentration conditions by the
First-Principles Calculations of Elastic Constants of Superconducting MgB2
Institute of Scientific and Technical Information of China (English)
GUO Hua-Zhong; CHEN Xiang-Rong; ZHU Jun; CAI Ling-Cang; GAO Jie
2005-01-01
@@ The five independent elastic constants of superconducting MgB2 are obtained using the first-principles plane wave method with the new relativistic analytic pseudopotential of the Hartwigsen-Goedecker-Hutter (HGH) scheme in the frame of local density approximation. The dependences of bulk modulus on temperature and pressure are also obtained. It is suggested that the HGH-type pseudopotentials are successful in investigating the ground-state mechanical properties of any solids.
Calculation of anisotropic few-group constants in asymptotic cells: the code ANICELL
International Nuclear Information System (INIS)
The theoretical background of the ANICELL computer program together with a user's manual is presented. ANICELL is a nuclear reactor neutron transport code which solves the traditional asymptotic and the so-called tilted flux transport problems in one-dimensional cylindrical geometry using linearly anisotropic scattering. The method of solution used is the first flight collision probability technique. Few-group constants including radial and axial diffusion coefficients for the cell are also prepared by the program. (author)
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).
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
Selected articles translated from Jadernye Konstanty (Nuclear Constants) volume 1, 1996
International Nuclear Information System (INIS)
This report contains selected articles translated from Jedernye Konstanty (Nuclear Constants). Eight papers are included and each one is separately indexed. Nuclear data libraries, Neutron Reactions, Low energy Photofission etc. are dealt with. Refs, figs, tabs
Design window calculations for a constant q' lithium blanket comparing lithium and sodium coolants
International Nuclear Information System (INIS)
In previous work, a design window approach has been applied to a liquid metal cooled, stagnant lithium breeding blanket, where the cooling tubes are spaced such that they all have the same heat flux per unit length (constant q'). This report is partly supplemental in that is is a detailed clarification of the equations and assumptions used, including several refinements. However, it also includes documentation for a revised version of the WINDOW code used to generate the design windows, and (as an example of the usefulness of the design window approach) a comparison of lithium cooling to sodium cooling of this blanket. The results confirm the desirability of lithium as a coolant
Quantum Monte Carlo calculations of two neutrons in finite volume
Klos, P.; Lynn, J. E.; Tews, I.; Gandolfi, S.; Gezerlis, A.; Hammer, H. -W.; Hoferichter, M.; Schwenk, A.
2016-01-01
Ab initio calculations provide direct access to the properties of pure neutron systems that are challenging to study experimentally. In addition to their importance for fundamental physics, their properties are required as input for effective field theories of the strong interaction. In this work, we perform auxiliary-field diffusion Monte Carlo calculations of the ground and first excited state of two neutrons in a finite box, considering a simple contact potential as well as chiral effectiv...
Energy Technology Data Exchange (ETDEWEB)
Anon.
1999-10-18
The Electronically Commutated Motor operated with 24 volt is the core piece of the new radial van produced by Helutech. Vertical parameters promise a permanently constant volume flow with this kind of drive. (orig.) [German] Der 'Electronically Commutated Motor', betrieben mit 24 Volt, ist das Herzstueck des neuen Radialventilators von Helutech. Senkrechte Kennlinien versprechen mit diesem Antrieb allzeit konstanten Volumenstrom. (orig.)
Takara, L.S.; Cunha, T M; Barbosa, P.; M.K. Rodrigues; Oliveira, M. F.; Nery, L E; J.A. Neder
2012-01-01
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinf...
Takara, L.S.; Cunha, T M; Barbosa, P.; M.K. Rodrigues; Oliveira, M. F.; Nery, L E; J.A. Neder
2012-01-01
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW) = rib cage (V RC) + abdomen (V AB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyper...
International Nuclear Information System (INIS)
The multiconfiguration Dirac-Hartree-Fock model has been employed to calculate the expectation values for the hyperfine splittings of the 5d96s22D3/2 and 5d96s22D5/2 levels of atomic gold. One-, two-, and three-body electron correlation effects involving all 79 electrons have been included in a systematic manner. The approximation employed in this study is equivalent to a complete-active-space approach. Calculated electric field gradients, together with experimental values of the electric quadrupole hyperfine-structure constants, allow us to extract a nuclear electric quadrupole moment Q(197Au)=521.5(5.0) mb.
International Nuclear Information System (INIS)
The structure of the SADKO-2 program system, providing for calculations of radiation transport by the group methods for protons, π-mesons within the energy range from 20 MeV to 10 TeV; for neutrons-from the thermal one to 10 TeV; for photons-from 0.01 up to 15 MeV. The SADKO system containing the program for calculation of complete and twice-differential cross section of inelastic hA-interaction, the program for calculation of group microcross sections for particles with energy above 20 MeV and the program for calculation of group microcross sections for isotope mixtures. The file of the group cross sections in a predetermined format, prepared with an account of the components composition of the shielding and detector substance, constitute the result of the SADKO-2 constant system operation. 25 refs., 7 figs
Sunaga, A.; Abe, M.; Hada, M.; Das, B. P.
2016-04-01
The scalar-pseudoscalar (S-PS) interaction, which has been predicted between the electrons and nuclei of atoms and molecules, violates parity- (P -) and time- (T -) reversal symmetries. The electric dipole moment of the electron (eEDM) and the S-PS interaction together give rise to an energy shift in paramagnetic polar molecules, which in principle can be measured. The determination of the S-PS interaction constant, ks ,A, for an atom A could be a sensitive probe of physics beyond the standard model. The upper limit for it can be obtained by combining the results of the measured energy shift mentioned above and the accurate quantum chemical calculation of the S-PS coefficient, Ws ,A. In this work, we use a method based on the four-component relativistic coupled-cluster singles and doubles (RCCSD) method to calculate this coefficient for YbF, one of the most promising candidates for the search of the eEDM and the S-PS interaction. We obtain Ws ,Yb=-40.5 (kHz ) with an estimated error of less than 10% for YbF. We also calculate the effective electric field (Eeff), the molecular dipole moment, and the parallel component of the hyperfine coupling constant (A∥) by the RCCSD method. The discrepancies in the results of these calculations with those of accurate measurements are used to estimate the accuracy of our calculation of Ws ,Yb.
Semi-empirical calculations of oscillator strengths and hyperfine constants for Ti II
International Nuclear Information System (INIS)
As the result of our studies on the atomic structure of complex atoms we produced high quality wave functions for both the even and odd systems of configurations. The quality of wave functions was proved via comparison of the expected and experimental hyperfine structure constants and gJ-factors. These wave functions were used for the parametrization of the oscillator strengths for electromagnetic transitions in Ti II, where reliable experimental data were available. The least squares fit to experimental values for some transitions, published in the NIST Atomic Spectra Database, allowed us to obtain the values of transition integrals and parametrize the oscillator strengths. - Highlights: • The method of simultaneous determination of all the attributes of atomic structure. • The semi-empirical method of parameterization of oscillator strengths. • Illustration of the method application for the example of Ti II data
International Nuclear Information System (INIS)
The ability of simple levels of ab initio molecular orbital theory to describe with reasonable accuracy the energetics of isotopic exchange processes is demonstrated. Three levels of ab initio molecular orbital theory have been surveyed. The first two levels are single-determinant Hartree-Foch methods utilizing the 3-21G split-valence and 6-31G* polarization basis sets. The third level, which is computationally the most complex, uses the 6-31G* basis set but allows for partial account of electron correlation by way of Moller-Plesset perturbation theory terminated at second order. Theoretical and spectroscopic equilibrium constants for reactions XH + XD reversible XD + H2 where XD is a hydride of the first row of the periodic table are tabulated
Energy Technology Data Exchange (ETDEWEB)
Marieen, A., E-mail: amarien@sckcen.be [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Mokni, N., E-mail: Nadia.mokni@upc.edu [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Valcke, E. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Olivella, S. [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Smets, S. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Li, X., E-mail: xli@sckcen.be [EIG EURIDICE, Boeretang 200, 2400 Mol (Belgium)
2013-01-15
Highlights: Black-Right-Pointing-Pointer The water uptake by Eurobitum is studied to judge the safety of geological disposal. Black-Right-Pointing-Pointer High pressures of up to 20 MPa are measured in constant volume water uptake tests. Black-Right-Pointing-Pointer The morphology of leached Eurobitum samples is studied with {mu}CT and ESEM. Black-Right-Pointing-Pointer The observations are reproduced by an existing CHM formulation for Eurobitum. - Abstract: The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at Belgian Nuclear Research Center SCK-CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluna, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO{sub 3} leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography ({mu}CT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to
International Nuclear Information System (INIS)
The importance of accounting for resonance self-screening effects in multigroup cross sections when calculating fast reactors and neutron shields is considered. Formulae for averaging cross sections over resonance features with the account of anisotropy for scattering with large energy losses are derived. The model calculations of neutron fluxes have been performed for a U-H mixture (rhosub(H)/rhosub(U)=0.1), a U-Fe-H mixture and for the latter with rhosub(5)/rhosub(Fe)=0.01-0.5. It is concluded that in hydrogen-containing reactors the effect may be significant if the core contains iron in large quantities. The cross section averaging is considered for 3 systems: the KBR-2 critical assembly, spherical model of a large breeder, critical sphere of UO2 with 30% enrichment. The scattering anisotropy changes the multiplication factors of the first two systems by about 0.3%
International Nuclear Information System (INIS)
We present data for the axial coupling constant gA of the nucleon obtained in lattice QCD with two degenerate flavors of dynamical nonperturbatively improved Wilson quarks. The renormalization is also performed nonperturbatively. For the analysis we give a chiral extrapolation formula for gA based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavors. Applying this formalism in a finite volume, we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume, we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point
International Nuclear Information System (INIS)
We present data for the axial coupling constant gA of the nucleon obtained in lattice QCD with two degenerate flavours of dynamical non-perturbatively improved Wilson quarks. The renormalisation is also performed non-perturbatively. For the analysis we give a chiral extrapolation formula for gA based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavours. Applying this formalism in a finite volume we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point. (Orig.)
ZZ DLC-14 AIR, Group Constant Library of Secondary Gamma Transport in Air for ANISN Calculation
International Nuclear Information System (INIS)
1 - Nature of physical problem solved: Format: ANISN, DOT, MORSE (FIDO format); Number of groups: 22 neutron / 18 gamma-ray; Nuclides: air; Origin: ENDF/B for neutron cross sections, DLC-4/HPIC for gamma-ray and DLC-12/POPLIB for secondary gamma-ray production. Weighting spectrum: 1/E for neutron cross sections. The basic idea behind the distribution of this ANISN input data is to allow potential users to repeat the ANISN calculations reported in ref. (1). It is felt that it will be more economical to repeat the calculations rather than to distribute the results of the Straker-Gritzner (1) calculations. However, the cross section part of the data can actually be used in DOT or MORSE or any transport code which will accept input cross section in the FIDO format. 2 - Method of solution: The sample input data for ANISN are for a P5, S16 calculation of the transport of neutrons and secondary gamma-rays from a 12.2 to 15 MeV point neutron source in an infinite air medium. The source is actually uniformly distributed in the first interval (500 cm radius) of a spherical medium of air with radius 3005 meters. The problem is set up for calculating various 'detector responses' by means of the 'activity' option available with ANISN. This is accomplished by providing a cross section table for a 'material' which has detector responses in certain table positions. Then the inclusion of appropriate input data for 22$ and 23$ arrays causes the group fluxes to be multiplied by the group response function values to give the desired answer. The neutron detector responses calculated by this sample problem are Henderson tissue dose, Snyder-Neufeld dose, tissue kerma, and air kerma. The gamma-ray response functions calculated are Henderson tissue dose and air kerma. The neutron cross sections were first reduced from point data from ENDF/B to a 104 fine group structure with a modified version of CSP, assuming a 1/E weighting factor. The gamma-ray data were reduced from point data from DLC
International Nuclear Information System (INIS)
Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent
Energy Technology Data Exchange (ETDEWEB)
Lunt, A. J. G., E-mail: alexander.lunt@eng.ox.ac.uk; Xie, M. Y.; Baimpas, N.; Korsunsky, A. M. [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom); Zhang, S. Y.; Kabra, S.; Kelleher, J. [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxford OX11 0QX (United Kingdom); Neo, T. K. [Specialist Dental Group, Mount Elizabeth Orchard, 3 Mount Elizabeth, #08-03/08-08/08-10, Singapore 228510 (Singapore)
2014-08-07
Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.
Lunt, A. J. G.; Xie, M. Y.; Baimpas, N.; Zhang, S. Y.; Kabra, S.; Kelleher, J.; Neo, T. K.; Korsunsky, A. M.
2014-08-01
Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.
Selected articles translated from Jadernye Konstanty (Nuclear Constants) volumes 1-2, 1995
International Nuclear Information System (INIS)
This report contains selected articles translated from Russian language which are dealing with nuclear constants. The MENDL-2 cross section library, universal library of fission products, evaluation of fission cross section for 237Np, evaluation of the photoneutron reaction cross sections, analysis of reaction rate measurements for determination of neutron energy spectra are specially dealt with. It contains five articles and each one is separately indexed. Refs, figs, tabs
Wijdeven, S.M.J.; Vaessen, O.H.B.; Hees, van A.F.M.; Olsthoorn, A.F.M.
2005-01-01
Dead wood is recognized as one of the key indicators for sustainable forest management and biodiversity. Accurate assessments of dead wood volume are thus necessary. In this study New volume models were designed based on actual volume measurements of coarse woody debris. The New generic model accura
Mariën, A.; Mokni, N.; Valcke, E.; Olivella, S.; Smets, S.; Li, X.
2013-01-01
The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at the Belgian Nuclear Research Center SCK•CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (μCT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO3 solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1-2 mm were hydrated (as derived from μCT and ESEM analyses), and only about 10-20% of the initial NaNO3 content was released by the samples. In the studied test
Energy Technology Data Exchange (ETDEWEB)
Debreczeny, M.P.; Sauer, K. [Lawrence Berkeley Lab., CA (United States); Zhou, J.; Bryant, D.A. [Pennsylvania State Univ., University Park, PA (United States)
1995-05-18
Rate constants for excitation energy transfer in light-harvesting protein, C-phycocyanin (PC), in the monomeric aggregation state, isolated from the cyanobacterium cynechococcus sp. PCC 7002, are calculated, using Foerster theory and compared with the results of time-resolved fluorescence measurements. The assignments of the energy-transfer rate constants in PC monomers are confirmed here by time-resolved fluorescence anisotropy measurements of the PC monomers isolated from both the wild-type and a mutant strain (cpcB/C155S) whose PC is missing the {beta}{sub 155} chromophore. It is concluded that the Foerster model of resonant energy transfer in the weak coupling limit successfully describes the dominant energy-transfer processes in this protein in the monomeric state. 31 refs., 3 figs., 4 tabs.
Energy Technology Data Exchange (ETDEWEB)
Debreczeny, M.F.; Sauer, K. [Lawrence Berkeley Lab., CA (United States); Zhou, J.; Bryant, D.A. [Pennsylvania State Univ., University Park, PA (United States)
1995-05-18
Resolution of the absorption spectrum of the {beta}{sub 155} chromophore in C-phycocyanin (PC) trimers is achieved by comparison of the steady state absorption spectra of ({alpha}{sup PC}{beta}{sup PC}){sub 3} and ({alpha}{sup PC}{beta}{sup *}){sub 3}. Comparison of the anisotropy decays of ({alpha}{sup PC}{beta}{sup PC}){sub 3} and ({alpha}{sup PC}{beta}{sup *}){sub 3} also greatly aids in the assignment of the dominant kinetic processes in PC trimers. A comparison is made of calculated Foerster rate constants for energy transfer with those rate constants resolved experimentally in the PC trimers. 35 refs.., 10 figs., 2 tabs.
Lattice Calculation of Heavy-Light Decay Constants with Two Flavors of Dynamical Quarks
Bernard, C; DeGrand, T A; DeTar, C E; Gottlieb, S; Heller, U M; McNeile, C; Orginos, K; Sugar, R; Toussaint, D; Gottlieb, Steven; Heller, Urs M.
2002-01-01
We present results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios in the presence of two flavors of light sea quarks ($N_f=2$). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us to improve our control of the continuum extrapolation. For our central values the masses of the sea quarks are not extrapolated to the physical $u$, $d$ masses; that is, the central values are "partially quenched." We find, for example, $f_B = 190 (7) (^{+24}_{-17}) (^{+11}_{-2})$ MeV, $f_{B_s}/f_B = 1.16 (1) (2) (2)$, $f_{D_s} = 241 (5) (^{+27}_{-26}) (^{+9}_{-4})$ MeV, and $f_{B}/f_{D_s} = 0.79 (2) (^{+5}_{-4}) (3)$, where the errors are statistical, systematic (within the partially quenched $N_f=2$ approximation), and systematic (due to the missing strange sea quark and to partial quenching), respectively. A calculation using "fat-link clover" valence fe...
Element-specific and constant parameters used for dose calculations in SR-Site
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Norden, Sara (Svensk Kaernbraenslehantering AB (Sweden)); Avila, Rodolfo; De la Cruz, Idalmis; Stenberg, Kristofer; Grolander, Sara (Facilia AB (Sweden))
2010-12-15
The report presents Best Estimate (BE) values and Probability Distribution Functions (PDFs) of Concentration Ratios (CR) for different types of terrestrial and aquatic biota and distribution coefficients (K{sub d}) for organic and inorganic deposits, as well as for suspended matter in freshwater and marine ecosystems. The BE values have been used in deterministic simulations for derivation of Landscape Dose Factors (LDF) applied for dose assessments in SR-Site. The PDFs have been used in probabilistic simulations for uncertainty and sensitivity analysis of the LDFs. The derivation of LDFs for SR-Site is described in /Avila et al. 2010/. The CR and K{sub d} values have been derived using both site-specific data measured at Laxemar and Forsmark during the site investigation program and literature data. These two data sources have been combined using Bayesian updating methods, which are described in detail in an Appendix, along with the input data used in the statistical analyses and the results obtained. The report also describes a kinetic-allometric model that was applied for deriving values of CR for terrestrial herbivores in cases when site and literature data for an element were missing. In addition, the report presents values for a number of other parameters used in the SR-Site Radionuclide Model for the biosphere: radionuclide decay-ingrowth data, elemental diffusivities, fractions of element content released during decomposition processes, ingestion of food, water and soil by cattle, elements retention fraction on plant surfaces during irrigation. The report also presents parameter values used in calculation of doses to a reference man: dose coefficients for inhalation, ingestion and external exposure, inhalation rates, ingestion rates of food and water
Element-specific and constant parameters used for dose calculations in SR-Site
International Nuclear Information System (INIS)
The report presents Best Estimate (BE) values and Probability Distribution Functions (PDFs) of Concentration Ratios (CR) for different types of terrestrial and aquatic biota and distribution coefficients (Kd) for organic and inorganic deposits, as well as for suspended matter in freshwater and marine ecosystems. The BE values have been used in deterministic simulations for derivation of Landscape Dose Factors (LDF) applied for dose assessments in SR-Site. The PDFs have been used in probabilistic simulations for uncertainty and sensitivity analysis of the LDFs. The derivation of LDFs for SR-Site is described in /Avila et al. 2010/. The CR and Kd values have been derived using both site-specific data measured at Laxemar and Forsmark during the site investigation program and literature data. These two data sources have been combined using Bayesian updating methods, which are described in detail in an Appendix, along with the input data used in the statistical analyses and the results obtained. The report also describes a kinetic-allometric model that was applied for deriving values of CR for terrestrial herbivores in cases when site and literature data for an element were missing. In addition, the report presents values for a number of other parameters used in the SR-Site Radionuclide Model for the biosphere: radionuclide decay-ingrowth data, elemental diffusivities, fractions of element content released during decomposition processes, ingestion of food, water and soil by cattle, elements retention fraction on plant surfaces during irrigation. The report also presents parameter values used in calculation of doses to a reference man: dose coefficients for inhalation, ingestion and external exposure, inhalation rates, ingestion rates of food and water
International Nuclear Information System (INIS)
The effect of orbital instabilities is investigated for spin-symmetry breaking perturbations, namely the Fermi-contact (FC) and spin-dipole (SD) contributions to the indirect nuclear spin-spin coupling constants. For the CO and N2 molecules the FC and SD contributions have been calculated and orbital-stability analyses for various interatomic distances have been carried out. This includes calculations at the Hartree-Fock self-consistent field (HF-SCF), coupled-cluster (CC) singles and doubles (CCSD), CC3, CCSD(T), CCSDT-4, CC singles, doubles, and triples (CCSDT) levels, and for the first time also at the CC singles, doubles, triples, and quadruples (CCSDTQ) level of theory. For calculations with relaxation of the reference orbitals in the presence of the perturbation, unphysical results are obtained over a wide range of the potential curve. This is due to a triplet instability of the Hartree-Fock reference determinant which leads to a pronounced pole in the FC and SD contributions. The effect of orbital instabilities in the relaxed methods is most dramatic for perturbative approaches like CCSD(T), while it is less pronounced for methods of the classical CC hierarchy. CC calculations without relaxation of the orbitals, i.e., so-called 'unrelaxed' calculations, do not show any of these effects
DEFF Research Database (Denmark)
Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus
The aim of this paper was to compare the indoor climate and the energy performance of a Constant Air Volume (CAV) system of 0.5h-1 with a Demand Controlled Ventilation (DCV) system controlled by occupancy and relative humidity for a studio apartment. Furthermore the impact of building materials...... hygroscopic properties on indoor climate and energy consumption was investigated for the two systems. Dynamic simulations of the studio apartment were carried out in the program WUFI+ with weather data from Copenhagen including outside temperature end relative humidity. For the non-hygroscopic case it was...
. Hussain. J. Al-Alkawi; Dhafir S. Al-Fattal; Abdul-Jabar H. Ali
2012-01-01
The aim of this work is to study the influence of the type of fiber glass mat on fatigue behavior of composite material which is manufactured from polyester and E-glass (woven roving, chopped strand mat (CSM)) as a laminate with a constant fiber volume fraction (VF) of 33%. The results showed that the laminates reinforced with E-glass (woven roving) [0/90, ±45.0/90] and [0/90, CSM, 0/90] have lower fatigue strength than the laminates reinforced with E-glass [0/90]3,[CSM]3 and [CSM, 0/90, CSM]...
Calculated Specific Volumes and Magnetic Moments of the 3d Transition Metal Monoxides
DEFF Research Database (Denmark)
Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.
We have performed self-consistent, spin-polarized band structure calculations as a function of the lattice spacing for the 3d metal monoxides in order to obtain the equilibrium lattice constants. The calculated binding from the 3d electrons and the occurrence of antiferromagnetism account...
International Nuclear Information System (INIS)
The code MIGROS-3 was developed from MIGROS-2. The main advantage of MIGROS-3 is its compatibility with the new conventions of the latest version of the Karlsruhe nuclear data library, KEDAK-3. Moreover, to some extent refined physical models were used and numerical methods were improved. MIGROS-3 allows the calculation of microscopic group cross sections of the ABBN type from isotopic neutron data given in KEDAK-format. All group constants, necessary for diffusion-, consistent P1- and Ssub(N)-calculations can be generated. Anisotropy of elastic scattering can be taken into account up to P5. A description of the code and the underlying theory is given. The input and output description, a sample problem and the program lists are provided. (orig.)
Bierón, Jacek; Indelicato, Paul; Jönsson, Per; Pyykkö, Pekka
2009-01-01
The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the expectation values for the hyperfine splittings of the 5d96s2 2D3/2 and 5d96s2 2D5/2 levels of atomic gold. One-, two-, and three-body electron correlation effects involving all 79 electrons have been included in a systematic manner. The approximation employed in this study is equivalent to a Complete Active Space (CAS) approach. Calculated electric field gradients, together with experimental values of the electric quadrupole hyperfine structure constants, allow us to extract a nuclear electric quadrupole moment Q(197Au)=521.5(5.0) mb.
Energy Technology Data Exchange (ETDEWEB)
Wander, Matthew C.; Shuford, Kevin L.; Rustad, James R.; Casey, William H.
2013-03-01
Aluminium possesses significant and diverse chemistry. Numerous compounds have been defined, and the elucidation of their chemistry is of significant geochemical interest. In this paper, a brucite-like, eight-aluminium aqueous cluster is modelled with density functional theory to identify its primary site of deprotonation and the associated pK(a) constant using both explicit (a full first solvent shell) and implicit solvent. Two methods for calculating the pK(a) are compared. We found that a bond density approach is better than a direct energy calculation for ions with large charge and high symmetry. The terminal aluminium atoms have equatorial ligated waters that in solvent have one long O-H bond. This site is more reactive than any of the other protons on the particle. Insights into the experimental crystal structure and Bader's Atoms in Molecules density analysis are presented as routes to reduce the computational time required for the identification of protonation sites.
Shanes, Fredrick Charles
1990-01-01
We have calculated the radius of gyration for a three dimensional linear flexible polymer chain with excluded volume interaction. The resulting is written as a perturbation series in the dimensionless excluded volume parameter z, and the series is written to O(z ^4) as = (Ll/6)(1 + 1.276190476z - 2.081948603z^2 + 6.564897382z^3 - 26.70629003z^4 + ...) where z = (3/2pil) ^{3/2}omegaL^ {1/2} with l the effective segment length, L the contour length, and omegal^2 the effective binary cluster integral for a pair of segments. The perturbation theory used to calculate has recently been applied to the mean square end-to-end distance for a linear flexible polymer chain by Muthukumar and Nickel. The theory essentially uses the continuum limit of the two -parameter model, Laplace transforms, and a diagrammatic expansion in conjunction with field theory methods. The perturbation theory was found to be much simpler to implement than the usual cluster expansion method, and thus we were able to extend the series from the previously known O(z^2) to O(z^4 ). The perturbation series for and are divergent, and are only valid for small z values. However, the most interesting information about these properties occurs for large z values. The large z limit of the and series were extracted by using the direct renormalization method, and estimates for the critical exponents and scaling amplitudes were obtained. A quantity that is of theoretical interest is the large z limit of the ratio 6/, since it is believed to be a universal constant (i.e., independent of the model). We calculated the ratio by applying four different renormalization schemes to the perturbation series for and , and we obtained a final estimate of 6 / = 0.9631 +/- 0.0003. We also analysed the Monte Carlo self-avoiding walk data for the ratio and found the large chain limit of 6 / = 0.9602 +/- 0.0002. The discrepancy between the two results could be due to the averaging procedure that we used to obtain the two
The calculation of volume and mass of the 14x14 type KOFA components
International Nuclear Information System (INIS)
A Systematic procedure for the calculation of the mass and volume of the 14x14 type KOFA components has been established in this report. And also the mass for the fuel assembly components from the commercial products has been measured and compared with the calculation results. (Author)
The calculation of volume and mass of the 16x16 type KOFA components
International Nuclear Information System (INIS)
A systematic procedure for the calculation of the mass and volume of the 16x16 type KOFA components has been established in this report. In addition the mass for the fuel assembly components from the commercial products has been measured and compared with the calculation results. (Author)
Directory of Open Access Journals (Sweden)
Chao Hu
2015-04-01
Full Text Available Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak, cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laser-scanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation project quality assessment with the laser scanning technology can be reduced by 70%−90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.
Directory of Open Access Journals (Sweden)
Hongzhan Xie
2015-06-01
Full Text Available The objective of this study was to investigate the macroscopic spray characteristics of different 0%–100% blends of biodiesel derived from drainage oil and diesel (BD0, BD20, BD50, BD80, BD100, such as spray tip penetration, average tip velocity at penetration, spray angle, average spray angle, spray evolution process, spray area and spray volume under different injection pressures (60, 70, 80, 90, 100 MPa and ambient pressures (0.1, 0.3, 0.5, 0.7, 0.9 MPa using a common rail system equipped with a constant volume chamber. The characteristic data was extracted from spray images grabbed by a high speed visualization system. The results showed that the ambient pressure and injection pressure had significant effects on the spray characteristics. As the ambient pressure increased, the spray angle increased, while the spray tip penetration and the peak of average tip velocity decreased. As the injection pressure increased, the spray tip penetration, spray angle, spray area and spray volume increased. The increasing blend ratio of biodiesel brought about a shorter spray tip penetration and a smaller spray angle compared with those of diesel. This is due to the comparatively higher viscosity and surface tension of biodiesel, which enhanced the friction effect between fuel and the injector nozzle surface and inhibited the breakup of the liquid jet.
Energy Technology Data Exchange (ETDEWEB)
Den, Takuya S.; Frey, Hans-Martin; Leutwyler, Samuel, E-mail: leutwyler@dcb.unibe.ch [Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3000 Bern 9 (Switzerland)
2014-11-21
The gas-phase rotational motion of hexafluorobenzene has been measured in real time using femtosecond (fs) time-resolved rotational Raman coherence spectroscopy (RR-RCS) at T = 100 and 295 K. This four-wave mixing method allows to probe the rotation of non-polar gas-phase molecules with fs time resolution over times up to ∼5 ns. The ground state rotational constant of hexafluorobenzene is determined as B{sub 0} = 1029.740(28) MHz (2σ uncertainty) from RR-RCS transients measured in a pulsed seeded supersonic jet, where essentially only the v = 0 state is populated. Using this B{sub 0} value, RR-RCS measurements in a room temperature gas cell give the rotational constants B{sub v} of the five lowest-lying thermally populated vibrationally excited states ν{sub 7/8}, ν{sub 9}, ν{sub 11/12}, ν{sub 13}, and ν{sub 14/15}. Their B{sub v} constants differ from B{sub 0} by between −1.02 MHz and +2.23 MHz. Combining the B{sub 0} with the results of all-electron coupled-cluster CCSD(T) calculations of Demaison et al. [Mol. Phys. 111, 1539 (2013)] and of our own allow to determine the C-C and C-F semi-experimental equilibrium bond lengths r{sub e}(C-C) = 1.3866(3) Å and r{sub e}(C-F) = 1.3244(4) Å. These agree with the CCSD(T)/wCVQZ r{sub e} bond lengths calculated by Demaison et al. within ±0.0005 Å. We also calculate the semi-experimental thermally averaged bond lengths r{sub g}(C-C)=1.3907(3) Å and r{sub g}(C-F)=1.3250(4) Å. These are at least ten times more accurate than two sets of experimental gas-phase electron diffraction r{sub g} bond lengths measured in the 1960s.
International Nuclear Information System (INIS)
We consider geodesic motion on three-dimensional Riemannian manifolds of constant negative curvature, topologically equivalent to S x ]0,1[, S a compact surface of genus two. To those trajectories which are recurrent in both directions of the time evolution t → +∞, t → -∞ a fractal limit set is associated whose Hausdorff dimension is intimately connected with the quantum mechanical energy ground state, determined by the Schroedinger operator on the manifold. We give a rather detailed and pictorial description of the hyperbolic spaces we have in mind, discuss various aspects of classical and quantum mechanical motion on them as far as they are needed to establish the connection between energy ground state and Hausdorff dimension and give finally some examples of ground state calculations in terms of Hausdorff dimensions of limit sets of classical trajectories. (orig.)
A simple and efficient GIS tool for volume calculations of submarine landslides
Völker, David Julius
2010-10-01
A numeric tool is presented for calculating volumes of topographic voids such as slump scars of landslides, canyons or craters (negative/concave morphology), or alternatively, bumps and hills (positive/convex morphology) by means of digital elevation models embedded within a geographical information system (GIS). In this study, it has been used to calculate landslide volumes. The basic idea is that a (singular) event (landslide, meteorite impact, volcanic eruption) has disturbed an intact surface such that it is still possible to distinguish between the former (undisturbed) landscape and the disturbance (crater, slide scar, debris avalanche). In such cases, it is possible to reconstruct the paleo-surface and to calculate the volume difference between both surfaces, thereby approximating the volume gain or loss caused by the event. I tested the approach using synthetically generated land surfaces that were created on the basis of Shuttle Radar Topography Mission data. Also, I show the application to two real cases, (1) the calculation of the volume of the Masaya Slide, a submarine landslide on the Pacific continental slope of Nicaragua, and (2) the calculation of the void of a segment of the Fish River Canyon, Namibia. The tool is provided as a script file for the free GIS GRASS. It performs with little effort, and offers a range of interpolation parameters. Testing with different sets of interpolation parameters results in a small range of uncertainty. This tool should prove useful in surface studies not exclusively on earth.
Cui, Yu-Jun; Loiseau, Cyril; Delage, Pierre; 10.1016/j.pce.2008.10.017
2008-01-01
Highly compacted sand-bentonite mixtures are often considered as possible engineered barriers in deep high-level radioactive waste disposals. In-situ, the saturation of these barriers from their initially unsaturated state is a complex hydro-mechanical coupled process in which temperature effects also play a role. The key parameter of this process is the unsaturated hydraulic conductivity of the barrier. In this paper, isothermal infiltration experiments were conducted to determine the unsaturated hydraulic conductivity according to the instantaneous profile method. To do so, total suction changes were monitored at different locations along the soil specimen by using resistivity relative humidity probes. Three constant volume infiltration tests were conducted showing, unexpectedly, a decrease of the hydraulic conductivity during infiltration. One test performed under free-swell conditions showed the opposite and standard trend. These observations were interpreted in terms of microstructure changes during wett...
Safronova, U I; Johnson, W R
2016-01-01
Energy levels of 30 low-lying states of Lu2+ and allowed electric-dipole matrix elements between these states are evaluated using a relativistic all-order method in which all single, double and partial triple excitations of Dirac-Fock wave functions are included to all orders of perturbation theory. Matrix elements are critically evaluated for their accuracy and recommended values of the matrix elements are given together with uncertainty estimates. Line strengths, transition rates and lifetimes of the metastable 5d(3/2) and 5d(5/2) states are calculated. Recommended values are given for static polarizabilities of the 6s, 5d and 6p states and tensor polarizabilities of the 5d and 6p(3/2) states. Uncertainties of the polarizability values are estimated in all cases. The blackbody radiation shift of the 6s(1/2)-5d(5/2) transition frequency of the Lu2+ ion is calculated with the aid of the recommended scalar polarizabilities of the 6s(1/2) and 5d(5/2) states. Finally, A and B hyperfine constants are determined f...
Fast near-field calculation for volume integral equations for layered media
Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav
2005-01-01
An efficient technique based on the Fast Fourier Transform (FFT) for calculating near-field scattering by dielectric objects in layered media is presented. A higher or-der method of moments technique is employed to solve the volume integral equation for the unknown induced volume current density. Afterwards, the scattered electric field can be easily computed at a regular rectangular grid on any horizontal plane us-ing a 2-dimensional FFT. This approach provides significant speedup in the nea...
Energy Technology Data Exchange (ETDEWEB)
Koponen, B.L.; Hampel, V.E.
1982-10-21
This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains - in chronological order - the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41.
International Nuclear Information System (INIS)
This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains - in chronological order - the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41
International Nuclear Information System (INIS)
The aim of this study was to evaluate a software tool for non-invasive preoperative volumetric assessment of potential donors in living donated liver transplantation (LDLT). Biphasic helical CT was performed in 56 potential donors. Data sets were post-processed using a non-commercial software tool for segmentation, volumetric analysis and visualisation of liver segments. Semi-automatic definition of liver margins allowed the segmentation of parenchyma. Hepatic vessels were delineated using a region-growing algorithm with automatically determined thresholds. Volumes and shapes of liver segments were calculated automatically based on individual portal-venous branches. Results were visualised three-dimensionally and statistically compared with conventional volumetry and the intraoperative findings in 27 transplanted cases. Image processing was easy to perform within 23 min. Of the 56 potential donors, 27 were excluded from LDLT because of inappropriate liver parenchyma or vascular architecture. Two recipients were not transplanted due to poor clinical conditions. In the 27 transplanted cases, preoperatively visualised vessels were confirmed, and only one undetected accessory hepatic vein was revealed. Calculated graft volumes were 1110±180 ml for right lobes, 820 ml for the left lobe and 270±30 ml for segments II+III. The calculated volumes and intraoperatively measured graft volumes correlated significantly. No significant differences between the presented automatic volumetry and the conventional volumetry were observed. A novel image processing technique was evaluated which allows a semi-automatic volume calculation and 3D visualisation of the different liver segments. (orig.)
Fast Near-Field Calculation for Volume Integral Equations for Layered Media
DEFF Research Database (Denmark)
Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav
An efficient technique based on the Fast Fourier Transform (FFT) for calculating near-field scattering by dielectric objects in layered media is presented. A higher or-der method of moments technique is employed to solve the volume integral equation for the unknown induced volume current density....... Afterwards, the scattered electric field can be easily computed at a regular rectangular grid on any horizontal plane us-ing a 2-dimensional FFT. This approach provides significant speedup in the near-field calculation in comparison to a straightforward numerical evaluation of the ra-diation integral since...
Directory of Open Access Journals (Sweden)
Robert Rietjens
2015-10-01
Full Text Available Introduction: It is unknown whether resistance training intensity or total volume of work affects the acute testosterone response to a greater extent. Purpose: Therefore, the circulating testosterone response was investigated following four resistance training protocols where total volume of work was held constant: moderate intensity (70% 1RM upper body (bench press, bent barbell row, and military press, moderate intensity lower body (squat and deadlift, high intensity (90% 1RM upper body, high intensity lower body. Methods: Total volume of work performed by each participant between protocols was maintained by adjusting the number of sets and or repetitions performed. Ten healthy, resistance trained men volunteered, and performed exercise protocols on separate days in a counterbalanced order. Capillary blood was obtained via finger stick at baseline (pre, immediately following the exercise session (post, and 1h post for the determination of testosterone concentration. Data were analyzed using a factorial ANOVA and significance was accepted at p≤ 0.05. Results: Both moderate intensity resistance protocols (upper and lower body significantly increased testosterone concentration (p=0.026, and p=0.024 respectively, whereas the high intensity protocols elevated testosterone but failed to achieve significance (upper p=0.272, lower p=0.658. No difference was noted in post session testosterone concentration between upper and lower body protocols for either moderate (p=0.248 or high intensity (p=0.990. Conclusion: This may be useful for novice resistance trained individuals because it provides evidence that moderate intensity is sufficient to increase testosterone compared to high intensity protocols that could be associated with a greater risk of injury.Keywords: hormone response, equal total work, high intensity protocol
Directory of Open Access Journals (Sweden)
L.S. Takara
2012-12-01
Full Text Available This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW = rib cage (V RC + abdomen (V AB] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE V CW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V CW regulation as EEV CW increased non-linearly in 17/30 "hyperinflators" and decreased in 13/30 "non-hyperinflators" (P < 0.05. EEV AB decreased slightly in 8 of the "hyperinflators", thereby reducing and slowing the rate of increase in end-inspiratory (EI V CW (P < 0.05. In contrast, decreases in EEV CW in the "non-hyperinflators" were due to the combination of stable EEV RC with marked reductions in EEV AB. These patients showed lower EIV CW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05. Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV CW regardless of the presence or absence of dynamic hyperinflation (P < 0.001. However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.
Energy Technology Data Exchange (ETDEWEB)
Takara, L.S.; Cunha, T.M.; Barbosa, P.; Rodrigues, M.K.; Oliveira, M.F.; Nery, L.E. [Setor de Função Pulmonar e Fisiologia Clínica do Exercício, Disciplina de Pneumologia, Departamento de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Neder, J.A. [Setor de Função Pulmonar e Fisiologia Clínica do Exercício, Disciplina de Pneumologia, Departamento de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen' s University, Kingston, ON (Canada)
2012-10-15
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V{sub CW}) = rib cage (V{sub RC}) + abdomen (V{sub AB})] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) V{sub CW} increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V{sub CW} regulation as EEV{sub CW} increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEV{sub AB} decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) V{sub CW} (P < 0.05). In contrast, decreases in EEV{sub CW} in the “non-hyperinflators” were due to the combination of stable EEV{sub RC} with marked reductions in EEV{sub AB}. These patients showed lower EIV{sub CW} and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV{sub CW} regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.
International Nuclear Information System (INIS)
This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) VCW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of VCW regulation as EEVCW increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEVAB decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) VCW (P < 0.05). In contrast, decreases in EEVCW in the “non-hyperinflators” were due to the combination of stable EEVRC with marked reductions in EEVAB. These patients showed lower EIVCW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIVCW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment
Oh, Won Sup; Chon, Sung-Bin
2016-01-01
Fluid resuscitation, hemostasis, and transfusion is essential in care of hemorrhagic shock. Although estimation of the residual blood volume is crucial, the standard measuring methods are impractical or unsafe. Vital signs, central venous or pulmonary artery pressures are inaccurate. We hypothesized that the residual blood volume for acute, non-ongoing hemorrhage was calculable using serial hematocrit measurements and the volume of isotonic solution infused. Blood volume is the sum of volumes...
Slavinić Petra; Cvetković Marko
2016-01-01
The volume calculation of geological structures is one of the primary goals of interest when dealing with exploration or production of oil and gas in general. Most of those calculations are done using advanced software packages but still the mathematical workflow (equations) has to be used and understood for the initial volume calculation process. In this paper a comparison is given between bulk volume calculations of geological structures using trapezoidal and Simpson’s rule and the ones obt...
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.
International Nuclear Information System (INIS)
Thermally induced displacements and stresses have been calculated by finite element analysis to guide the design, operation, and data interpretation of the in situ heating experiments in a granite formation at Stripa, Sweden. There are two full-scale tests with electrical heater canisters comparable in size and power to those envisaged for reprocessed high level waste canisters and a time-scaled test. To provide a simple theoretical basis for data analysis, linear thermoelasticity was assumed. Constant (temperature-independent) thermal and mechanical rock properties were used in the calculations. These properties were determined by conventional laboratory testing on small intact core specimens recovered from the Stripa test site. Two-dimensional axisymmetric models were used for the full-scale experiments, and three-dimensional models for the time-scaled experiment. Highest compressive axial and tangential stresses are expected at the wall of the heater borehole. For the 3.6 kW full-scale heated experiment, maximum compressive tangential stress was predicted to be below the unconfined compressive strength of Stripa granite, while for the 5 kW experiment, the maximum was approximately equal to the compressive strength before the concentric ring of eight 1 kW peripheral heaters was activated, but would exceed that soon afterwards. Three zones of tensile thermomechanical stresses will occur in each full-scale experiment. Maximum vertical displacements range from a fraction of a millimeter over most of the instrumented area of the time-scaled experiment to a few millimeters in the higher-power full-scale experiment. Radial displacements are typically half or less than vertical displacements. The predicted thermomechanical displacements and stresses have been stored in an on-site computer to facilitate instant graphic comparison with field data as the latter are collected
International Nuclear Information System (INIS)
Irradiation tests have shown that U-Mo dispersion fuel suffers from interaction between the fuel and the aluminum matrix at higher temperature. A potential solution to mitigate these phenomena is to use a fuel alloy foil in place of the fuel-aluminum dispersion. This monolithic fuel provides a lower fuel-matrix interfacial surface area and a much higher uranium density than dispersion type fuel. Internal stresses will arise, during fabrication and operating conditions, in the interface between fuel and cladding materials due to the difference in the thermal expansion coefficients and elastic constants. Our aim is to ascertain these properties for the gamma phase in the U-Mo alloy from the knowledge of its internal energy as a function of deformation. Internal energy of the disordered phase is obtained as a cluster expansion from AB initio calculated interaction parameters in each of three deportation modes: Hydrostatic, tetragonal and trigonal. Preliminary results are presented that have served as a proof of method suitability. (author)
Energy Technology Data Exchange (ETDEWEB)
Jackowski, K. [Faculty of Chemistry, Warsaw Univ. (Poland)
1994-12-31
Solid ammonia and methyl cyanide has been used as model substances for study of intermolecular effects in screening constants calculation. The NMR gas-to-liquid shift effects have been measured and correlated with theoretical calculations. 26 refs, 1 fig., 2 tabs.
Dielectric Constant of Suspensions
Mendelson, Kenneth S.; Ackmann, James J.
1997-03-01
We have used a finite element method to calculate the dielectric constant of a cubic array of spheres. Extensive calculations support preliminary conclusions reported previously (K. Mendelson and J. Ackmann, Bull. Am. Phys. Soc. 41), 657 (1996).. At frequencies below 100 kHz the real part of the dielectric constant (ɛ') shows oscillations as a function of the volume fraction of suspension. These oscillations disappear at low conductivities of the suspending fluid. Measurements of the dielectric constant (J. Ackmann, et al., Ann. Biomed. Eng. 24), 58 (1996). (H. Fricke and H. Curtis, J. Phys. Chem. 41), 729 (1937). are not sufficiently sensitive to show oscillations but appear to be consistent with the theoretical results.
Directory of Open Access Journals (Sweden)
Hong-Meng Li
2014-07-01
Full Text Available An experimental study of the intrinsic instabilities of H2/CO lean (φ = 0.4 to φ = 1.0 premixed flames at different hydrogen fractions ranging from 0% to 100% at elevated pressure and room temperature was performed in a constant volume vessel using a Schlieren system. The unstretched laminar burning velocities were compared with data from the previous literature and simulated results. The results indicate that excellent agreements are obtained. The cellular instabilities of syngas-air flames were discussed and critical flame radii were measured. When hydrogen fractions are above 50%, the flame tends to be more stable as the equivalence ratio increases; however, the instability increases for flames of lower hydrogen fractions. For the premixed syngas flame with hydrogen fractions greater than 50%, the decline in cellular instabilities induced by the increase in equivalence ratio can be attributed to a reduction of diffusive-thermal instabilities rather than increased hydrodynamic instabilities. For premixed syngas flames with hydrogen fractions lower than 50%, as the equivalence ratio increases, the cellular instabilities become more evident because the enhanced hydrodynamic instabilities become the dominant effect. For premixed syngas flames, the enhancement of cellular instabilities induced by the increase in hydrogen fraction is the result of both increasing diffusive-thermal and hydrodynamic instabilities.
Investigations on the necessity of dose calculations for several planes of the target volume
International Nuclear Information System (INIS)
In radiotherapy planning, the shape of a target volume can at present be exactly delimited by means of computed tomography. A method often applied is to project the largest target volume scan on the plane of the central ray and to calculate the dose in this plane. This method does not allow to take into account any change of the target volume scan which will be mainly due to the body contours of the patient. The results of dose calculations made in several planes for pharyngeal and laryngeal tumors are presented. With this procedure, 33 out of 60 irradiation techniques for nine tumor sites meet the requirements with regard to the central ray plane. If several planes are regarded, this is only true for ten irradiation plans. If is therefore absolutely necessary to calculate the doses of several planes if the target volume has an irregular shape or if the body contours vary considerably. This is the only way to prevent a false treatment caused by possibly severe dose excesses or dose insufficiencies in radiotherapy. (orig.)
Institute of Scientific and Technical Information of China (English)
Song Weiming; Hu Qilin; Chang Xuan; Chen Sanping; Xie Gang; Gao Shengli
2006-01-01
A ternary solid complex Yb(Et2dtc)3(phen) was obtained from the reaction of hydrous ytterbium chloride with sodium diethyldithiocarbamate (NaEt2dtc), and 1, 10-phenanthroline (o-phen·H2O) in absolute ethanol.The bonding characteristics of the complex were characterized by IR.The result shows Yb3+ bands with two sulfur atoms in the Na(Et2dtc)3 and two nitrogen atoms in the o-phen.The enthalpy change of liquid-phase reaction of formation of the complex ΔrHθm (l), was determined as being (-24.838±0.114) kJ·mol-1 at 298.15 K, by an RD-496 Ⅲ type heat conduction microcalormeter.The enthalpy change of the solid-phase reaction of formation of the complex ΔrHθm (s), was calculated as being (108.015±0.479) kJ·mol-1 on the basis of an appropriate thermochemistry cycle.The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature during the liquid-phase reaction.Fundamental parameters, the activation enthalpy, ΔHθ≠, the activation entropy, ΔSθ≠, the activation free energy, ΔGθ≠, the apparent reaction rate constant k, the apparent activation energy E, the pre-exponential constant A, and the reaction order n, were obtained by a combination of the reaction thermodynamic and kinetic equations with the data from the thermokinetic experiments.At the same time, the molar heat capacity of the complex cm, p, was determined to be (86.34±1.74) J·mol-1·K-1 by the same microcalormeter.The constant-volume combustion energy of the complex, ΔcU, was determined to be (-17954.08±8.11) kJ·mol-1 by an RBC-Ⅱ type rotating-bomb calorimeter at 298.15 K.Its standard enthalpy of combustion, ΔcHθm, and standard enthalpy of formation, ΔfHθm, were calculated to be (-17973.29±8.11) kJ·mol-1 and (-770.36±9.02) kJ·mol-1, respectively.
International Nuclear Information System (INIS)
Examples of calculation of the rate constants for outersphere electron-transfer reactions with participation of transition metal (V, Ru) complexes characterized by an essential reorganization of intramolecular degree of freedom corresponding to the metal-ligand bond oscillation. Experimental and theoretical values of the rate constants, of activation energies and transemission coefficients are given, as well as thermodynamic characteristics (δH0, δS0). Five out of considered six reactions permit to obtain a satisfactory agreement between theory and experiment both with respext to the rate constants and the activation energies
Calculation of mean dose deposited in expended volume around an ion path
Institute of Scientific and Technical Information of China (English)
LiuXiao－Wei; ZhangChun－Xiang
1998-01-01
Using the relation of radial dose distributioin which is inverse proportion to suqare of radial distance,and considering angular distribution of secondary electrons,an analytical formula of mean dose deposited in extended volume around an ion is given and the inactivation cross sections of heavy ions are calculated.The results are in reasonable agreement with experimental data.Compared to the numerical integral methods,the method using analytical formulae is straightforward and simple.
International Nuclear Information System (INIS)
The normal tissue complication probability (NTCP) is a predictor of radiobiological effect for organs at risk (OAR). The calculation of the NTCP is based on the dose-volume-histogram (DVH) which is generated by the treatment planning system after calculation of the 3D dose distribution. Including the NTCP in the objective function for intensity modulated radiation therapy (IMRT) plan optimization would make the planning more effective in reducing the postradiation effects. However, doing so would lengthen the total planning time. The purpose of this work is to establish a method for NTCP determination, independent of a DVH calculation, as a quality assurance check and also as a mean of improving the treatment planning efficiency. In the study, the CTs of ten randomly selected prostate patients were used. IMRT optimization was performed with a PINNACLE3 V 6.2b planning system, using planning target volume (PTV) with margins in the range of 2 to 10 mm. The DVH control points of the PTV and OAR were adapted from the prescriptions of Radiation Therapy Oncology Group protocol P-0126 for an escalated prescribed dose of 82 Gy. This paper presents a new model for the determination of the rectal NTCP (RNTCP). The method uses a special function, named GVN (from Gy, Volume, NTCP), which describes the RNTCP if 1 cm3 of the volume of intersection of the PTV and rectum (Rint) is irradiated uniformly by a dose of 1 Gy. The function was 'geometrically' normalized using a prostate-prostate ratio (PPR) of the patients' prostates. A correction of the RNTCP for different prescribed doses, ranging from 70 to 82 Gy, was employed in our model. The argument of the normalized function is the Rint, and parameters are the prescribed dose, prostate volume, PTV margin, and PPR. The RNTCPs of another group of patients were calculated by the new method and the resulting difference was <±5% in comparison to the NTCP calculated by the PINNACLE3 software where Kutcher's dose-response model for
International Nuclear Information System (INIS)
Method is proposed for calculating the constants of acid-base equilibria at the oxide-electrolyte interface. The method is based on the electrokinetic potential dependence on ph value at different electrolyte concentrations. It is shown that the calculated constant values for La2O3 and ZrO2 equal correspondingly 7.3 and 3.9 (pK10); 11.9 and 9.1 (pK20); 9.2 and 5.8 (pK30); 10.0 and 7.2 (pK40) agree well with literature data. 21 refs.; 3 figs.; 3 tabs
DEFF Research Database (Denmark)
Enevoldsen, Thomas; Oddershede, Jens; Sauer, Stephan P. A.
1998-01-01
We present correlated calculations of the indirect nuclear spin-spin coupling constants of HD, HF, H2O, CH4, C2H2, BH, AlH, CO and N2 at the level of the second-order polarization propagator approximation (SOPPA) and the second-order polarization propagator approximation with coupled......-cluster singles and doubles amplitudes - SOPPA(CCSD). Attention is given to the effect of the so-called W 4 term, which has not been included in previous SOPPA spin-spin coupling constant studies of these molecules. Large sets of Gaussian basis functions, optimized for the calculation of indirect nuclear spin...
Zhang, Ji
2013-07-01
This paper presents measurements of the soot temperature and KL factor for biodiesel and diesel combustion in a constant volume chamber using a two-color technique. This technique uses a high-speed camera coupled with two narrowband filters (550. nm and 650. nm, 10. nm FWHM). After calibration, statistical analysis shows that the uncertainty of the two-color temperature is less than 5%, while it is about 50% for the KL factor. This technique is then applied to the spray combustion of biodiesel and diesel fuels under an ambient oxygen concentration of 21% and ambient temperatures of 800, 1000 and 1200. K. The heat release result shows higher energy utilization efficiency for biodiesel compared to diesel under all conditions; meanwhile, diesel shows a higher pressure increase due to its higher heating value. Biodiesel yields a lower temperature inside the flame area, a longer soot lift-off length, and a smaller soot area compared to diesel. Both the KL factor and the total soot with biodiesel are lower than with diesel throughout the entire combustion process, and this difference becomes larger as the ambient temperature decreases. Biodiesel shows approximately 50-100. K lower temperatures than diesel at the quasi-steady stage for 1000 and 1200. K ambient temperature, while diesel shows a lower temperature than biodiesel at 800. K ambient. This result may raise the question of how important the flame temperature is in explaining the higher NO. x emissions often observed during biodiesel combustion. Other factors may also play an important role in controlling NO. x emissions. Both biodiesel and diesel temperature measurements show a monotonic dependence on the ambient temperature. However, the ambient temperature appears to have a more significant effect on the soot formation and oxidation in diesel combustion, while biodiesel combustion soot characteristics shows relative insensitivity to the ambient temperature. © 2013 Elsevier Ltd.
Naser Samadi; Mina Salamati; Abdolhossein Naseri
2013-01-01
In traditional spectrophotometric determination of stability constants of complexation, it is necessary to find a wavelength at which only one of the components has absorbance without any spectroscopic interference of the other reaction components. In the present work, a simple multi-wavelength model-based method has been developed to determine stability constants for complexation reaction regardless of the spectra overlapping of components. Also, pure spectra and concentration profiles of al...
KANOUN-BOUAYED, Nawel; Kanoun, Mohammed Benali; Goumri-Said, Souraya
2011-01-01
We report plane-wave pseudo-potential ab initio calculations using density functional theory in order to investigate the structural parameters, elastic constants, bonding properties and polycrystalline parameters of copper nitrides in zincblende, rocksalt and fluorite structures. Total and partial densities of states indicate a metallic character of these copper nitrides. We estimate bond strengths and types of atomic bonds using Mulliken charge density population analysis and by calculating ...
International Nuclear Information System (INIS)
We have employed the framework of Bethe-Salpeter equation under Covariant Instantaneous Ansatz to calculate the leptonic decay constants of unequal mass pseudoscalar mesons. In the Dirac structure of BS wave function, the covariants are incorporated from their complete set in accordance with a recently proposed power counting rule, order-by-order in powers of inverse of meson mass. The decay constants are calculated incorporating both Leading Order (LO) as well as Next-to-leading Order (NLO) Dirac covariants. The contribution of both LO as well as NLO covariants to decay constants are studied in detail in this paper. The results are found to improve dramatically, and hence validating the power counting rule which also provides a practical means of incorporating Dirac covariants in the BS wave function of a hadron. (author)
International Nuclear Information System (INIS)
New values of the indirect spin-spin coupling constants in CH4, SiH4 and GeH4, derived from experiment and ab initio calculations, are reported. The new experimental values of 1J(CH), 1J(SiH) and 1J(GeH) are obtained from gas-phase NMR spectra. The dependence of the measured one-bond coupling constants on the density is analysed and the results are extrapolated to zero-density point to eliminate the effects due to intermolecular forces. In the calculation of the coupling constants, at the nonrelativistic level coupled cluster singles and doubles (CCSD) perturbation theory is used and the basis set convergence of the results is discussed. The relativistic corrections are estimated from Dirac-Hartree-Fock (DHF) calculations. The final theoretical values are obtained adding available estimates of the vibrational and temperature corrections. The agreement of the calculated and experimental 1J(XH), X = C, Si, Ge, constants is very satisfying, the differences are approximately 1-3%
DEFF Research Database (Denmark)
Provasi, Patricio F.; Caputo, María Cristina; Sauer, Stephan P. A.; Alkorta, Ibon; Elguero, José
2012-01-01
A theoretical study of FCCF:(HF)n complexes, with n = 1 and 2, has been carried out by means of ab initio computational methods. Two types of complexes are formed: those with FH···p interactions and those with FH···FC hydrogen bonds. The indirect spin–spin coupling constants have been calculated ...
Czech Academy of Sciences Publication Activity Database
Heimdal, J.; Kaukonen, M.; Srnec, Martin; Rulíšek, Lubomír; Ryde, U.
2011-01-01
Roč. 12, č. 17 (2011), s. 3337-3347. ISSN 1439-4235 R&D Projects: GA MŠk LC512 Institutional research plan: CEZ:AV0Z40550506 Keywords : acidity constants * enzymes * free-energy * perturbation * molecular modelling * reduction potentials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.412, year: 2011
Variations on calculating left-ventricular volume with the radionuclide count-based method
International Nuclear Information System (INIS)
Various methods for the calculation of left-ventricular volume by the count-based method utilizing red-blood-cell labeling with /sup 99m/Tc and a parallel-hole collimator are evaluated. Attenuation correction, linked to an additional left posterior oblique view, is utilized for all 26 patients. The authors examine (1) two methods of calculating depth, (2) the use of a pair of attenuation coefficients, (3) the optimization of attenuation coefficients, and (4) the employment of an automated program for expansion of the region of interest. The standard error of the estimate (SEE) from the correlation of the radionuclide volumes with the contrast-angiography volumes, and the root-mean-square difference between the two volume sets at the minimum SEE are computed. It is found that optimizing a single linear attenuation coefficient assumed for attenuation correction best reduces the value of the SEE. The average of the optimum value from the end-diastolic data and that from the end-systolic data is 0.11 cm-1. This value agrees with the mean minus one standard deviation value determined independently from computed tomography scans (0.13-0.02 cm-1). It is also found that expansion of the region of interest beyond the second-derivative edge with an automated program, in order to correctly include more counts, does not lower the SEE as hoped. This result is in contrast to the results of others with different data and a manual method. Possible causes for the difference are given
International Nuclear Information System (INIS)
The diffusion of pollutants in gaseous or liquid media is investigated. At first, the molecular diffusion is studied using the continuous point source model. Pollutant concentration is determined by means of Green's function. Then follows the investigation of turbulent diffusion in a flowing medium. The K-theory is applied in order to calculate the pollutant concentrations for short-time or continuous point source, line source, large-area source, or volume source in a flow field of an anisotropic medium. The extensive differential equations and their analytical solutions are explained in detail. (KW)
Zhou, Fuyang; Li, Jiguang; Wang, Jianguo
2015-01-01
The multi-configuration Dirac-Hartree-Fock method was employed to calculate the total and excitation energies, oscillator strengths and hyperfine structure constants for low-lying levels of Sm I. In the first-order perturbation approximation, we systematically analyzed correlation effects from each electrons and electron pairs. It was found that the core correlations are of importance for physical quantities concerned. Based on the analysis, the important configuration state wave functions were selected to constitute atomic state wave functions. By using this computational model, our excitation energies, oscillator strengths, and hyperfine structure constants are in better agreement with experimental values than earlier theoretical works.
International Nuclear Information System (INIS)
Aim: To compare left ventricular ejection fraction (LVEF), end-diastolic volumes (EDV) and end-systolic volumes (ESV) measured by quantitative gated SPECT (QGSPECT) in studies acquired with and without magnification factor (zoom). Material and Methods: We studied 30 consecutive patients (17 men, ages 61±14 years) referred for myocardial perfusion evaluation with a 2-day protocol. Studies were performed after injection of 925 MBq (25 mCi) of 99mTc-MIBI in the resting state. Gated SPECT was first acquired using a x2 zoom factor and immediately repeated with x1 zoom (no magnification), using a 64x64 matrix and 8 frames/cardiac cycle. Patients with arrhythmia were not included in the investigation. According to the median EDV calculated with the x2 zoom acquisition, the population was further divided in two sub-groups regarding the size of the LV cavity. Average LVEF, EDV, ESV and difference between values (delta) were then calculated for the total population and for each sub-group (a and b). Results: For the total population, results are expressed.Pearson correlation showed r=0.954 between LVEF with and without zoom (p<0.0001), but linear regression analysis did not fit a specific model (p=0.18). Median EDV with zoom was 92.5 ml, allowing to separate 15 cases with EDV above (a) and 15 below that value (b). Results for both sub-groups are presented. Conclusion: Calculated LVEF is higher with no zoom, at the expense of decreasing both EDV and ESV. Although differences were very significant for all parameters, ESV changes were specially relevant with no zoom, particularly in patients with smaller hearts. Although good correlation was found between LVEF with and without zoom, no specific correction factor was found to convert one value into the other. Magnification factor should be kept constant in gated SPECT if calculated LVEF values QGSPECT are expected to be reliable, and validation of the method using different zoom factors should be considered
Recording and Calculating Gunshot Sound—Change of the Volume in Reference to the Distance
Nikolaos, Tsiatis E.
2010-01-01
An experiment was conducted in an open practice ground (shooting range) regarding the recording of the sound of gunshots. Shots were fired using various types of firearms (seven pistols, five revolvers, two submachine guns, one rifle, and one shotgun) in different calibers, from several various distances with reference to the recording sources. Both, a conventional sound level meter (device) and a measurement microphone were used, having been placed in a fixed point behind the shooting line. The sound of each shot was recorded (from the device). At the same time the signal received by the microphone was transferred to a connected computer through an appropriate audio interface with a pre-amplifier. Each sound wave was stored and depicted as a wave function. After the physic-mathematical analysis of these depictions, the volume was calculated in the accepted engineering units(Decibels or dB) of Sound Pressure Level (SPL). The distances from the recording sources were 9.60 meters, 14.40 m, 19.20 m, and 38.40 m. The experiment was carried out by using the following calibers: .22 LR, 6.35 mm(.25 AUTO), 7.62 mm Tokarev(7,62×25), 7.65 mm(.32 AUTO), 9 mm Parabellum(9×19), 9 mm Short(9×17), 9 mm Makarov(9×18), .45 AUTO, .32 S&W, .38 S&W, .38 SPECIAL, .357 Magnum, 7,62 mm Kalashnikov(7,62×39) and 12 GA. Tables are given for the environmental conditions (temperature, humidity, altitude & barometric pressure), the length of the barrel of each gun, technical characteristics of the used ammunition, as well as for the volume taken from the SLM. The data for the sound intensity were collected after 168 gunshots (158 single shot & 10 bursts). According to the results, a decreasing of the volume, equivalent to the increasing of the distance, was remarked, as it was expected. Values seem to follow the Inverse square Law. For every doubling of the distance from the sound source, the sound intensity diminishes by 5.9904±0.2325 decibels (on average). In addition, we have the
Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations
Albright, M.; Kapusta, J.; Young, C.
2014-08-01
We match three hadronic equations of state at low energy densities to a perturbatively computed equation of state of quarks and gluons at high energy densities. One of them includes all known hadrons treated as point particles, which approximates attractive interactions among hadrons. The other two include, in addition, repulsive interactions in the form of excluded volumes occupied by the hadrons. A switching function is employed to make the crossover transition from one phase to another without introducing a thermodynamic phase transition. A χ2 fit to accurate lattice calculations with temperature 100physically reasonable models include the excluded-volume effect. Not only do they include the effects of attractive and repulsive interactions among hadrons, but they also achieve better agreement with lattice QCD calculations of the equation of state. The equations of state constructed in this paper do not result in a phase transition, at least not for the temperatures and baryon chemical potentials investigated. It remains to be seen how well these equations of state will represent experimental data on high-energy heavy-ion collisions when implemented in hydrodynamic simulations.
Finite Volume Numerical Methods for Aeroheating Rate Calculations from Infrared Thermographic Data
Daryabeigi, Kamran; Berry, Scott A.; Horvath, Thomas J.; Nowak, Robert J.
2006-01-01
The use of multi-dimensional finite volume heat conduction techniques for calculating aeroheating rates from measured global surface temperatures on hypersonic wind tunnel models was investigated. Both direct and inverse finite volume techniques were investigated and compared with the standard one-dimensional semi-infinite technique. Global transient surface temperatures were measured using an infrared thermographic technique on a 0.333-scale model of the Hyper-X forebody in the NASA Langley Research Center 20-Inch Mach 6 Air tunnel. In these tests the effectiveness of vortices generated via gas injection for initiating hypersonic transition on the Hyper-X forebody was investigated. An array of streamwise-orientated heating striations was generated and visualized downstream of the gas injection sites. In regions without significant spatial temperature gradients, one-dimensional techniques provided accurate aeroheating rates. In regions with sharp temperature gradients caused by striation patterns multi-dimensional heat transfer techniques were necessary to obtain more accurate heating rates. The use of the one-dimensional technique resulted in differences of 20% in the calculated heating rates compared to 2-D analysis because it did not account for lateral heat conduction in the model.
Directory of Open Access Journals (Sweden)
Hamit Yurtseven
2012-01-01
Full Text Available The temperature dependence of the static dielectric constant ( is calculated close to the smectic A-smectic B ( transition ( = 71.3°C for the liquid crystal compound B5. By expanding the free energy in terms of the order parameter in the mean field theory, the expression for the dielectric susceptibility (dielectric constant is derived and is fitted to the experimental data for which was obtained at the field strengths of 0 and 67 kV/cm from literature. Coefficients in the free energy expansion are determined from our fit for the transition of B5. Our results show that the observed behaviour of the dielectric constant close to the transition in B5 can be described satisfactorily by our mean field model.
Mathews, Alyssa
Emissions from the combustion of fossil fuels are a growing pollution concern throughout the global community, as they have been linked to numerous health issues. The freight transportation sector is a large source of these emissions and is expected to continue growing as globalization persists. Within the US, the expanding development of the natural gas industry is helping to support many industries and leading to increased transportation. The process of High Volume Hydraulic Fracturing (HVHF) is one of the newer advanced extraction techniques that is increasing natural gas and oil reserves dramatically within the US, however the technique is very resource intensive. HVHF requires large volumes of water and sand per well, which is primarily transported by trucks in rural areas. Trucks are also used to transport waste away from HVHF well sites. This study focused on the emissions generated from the transportation of HVHF materials to remote well sites, dispersion, and subsequent health impacts. The Geospatial Intermodal Freight Transport (GIFT) model was used in this analysis within ArcGIS to identify roadways with high volume traffic and emissions. High traffic road segments were used as emissions sources to determine the atmospheric dispersion of particulate matter using AERMOD, an EPA model that calculates geographic dispersion and concentrations of pollutants. Output from AERMOD was overlaid with census data to determine which communities may be impacted by increased emissions from HVHF transport. The anticipated number of mortalities within the impacted communities was calculated, and mortality rates from these additional emissions were computed to be 1 in 10 million people for a simulated truck fleet meeting stricter 2007 emission standards, representing a best case scenario. Mortality rates due to increased truck emissions from average, in-use vehicles, which represent a mixed age truck fleet, are expected to be higher (1 death per 341,000 people annually).
Melguizo-Gavilanes, J.; Bauwens, L.
2013-05-01
The induction time measured in shock tube experiments is typically converted into kinetic data assuming that the reaction takes place in a constant volume process, thus neglecting spatial gradients. The actual process of shock ignition is, however, both time- and space-dependent; ignition takes place at a well-defined location, and subsequently a front travels, which may couple with the pressure wave that it created and forms a detonation wave behind the shock that reflects off the wall. To assess how different the actual processes are compared with the constant volume assumption, a numerical study was performed using a simplified three step chain-branching kinetic scheme. To overcome the difficulties that arise when simulating shock-induced ignition due to the initial absence of a domain filled with shocked reactive mixture, the problem is solved in a transformed frame of reference. Furthermore, initial conditions are derived from short-time asymptotics, which resolves the initial singularity. The induction times obtained using the full unsteady formulation with those of the homogeneous explosion are compared for various values of the heat release. Results for the spatially dependent formulation show that the evolution of the post-shock flow is complex, and that it leads to a gradient in induction times, after the passage of the reflected shock. For all cases simulated, thermal explosion initially occurs very close to the wall, and the corresponding induction time is found to be larger than that predicted under the constant volume assumption. As the measurement is made further away however, the actual time interval between passage of the reflected shock, and the specified pressure increase denoting ignition, decreases to a value close to zero, corresponding to that obtained along a Rayleigh line matching that of a steady ZND process (assuming a long enough tube). In situations where the constant volume assumption is expected to be weak, more accurate kinetic data
Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Demissie, Taye B; Ruud, Kenneth
2015-08-11
We present an implementation of the nuclear spin-rotation (SR) constants based on the relativistic four-component Dirac-Coulomb Hamiltonian. This formalism has been implemented in the framework of the Hartree-Fock and Kohn-Sham theory, allowing assessment of both pure and hybrid exchange-correlation functionals. In the density-functional theory (DFT) implementation of the response equations, a noncollinear generalized gradient approximation (GGA) has been used. The present approach enforces a restricted kinetic balance condition for the small-component basis at the integral level, leading to very efficient calculations of the property. We apply the methodology to study relativistic effects on the spin-rotation constants by performing calculations on XHn (n = 1-4) for all elements X in the p-block of the periodic table and comparing the effects of relativity on the nuclear SR tensors to that observed for the nuclear magnetic shielding tensors. Correlation effects as described by the density-functional theory are shown to be significant for the spin-rotation constants, whereas the differences between the use of GGA and hybrid density functionals are much smaller. Our calculated relativistic spin-rotation constants at the DFT level of theory are only in fair agreement with available experimental data. It is shown that the scaling of the relativistic effects for the spin-rotation constants (varying between Z(3.8) and Z(4.5)) is as strong as for the chemical shieldings but with a much smaller prefactor. PMID:26574455
System of constants to calculate neutron transport with energy 10-2-4x108 eV
International Nuclear Information System (INIS)
A description of the library of nuclear data to calculate neutron transport in the energy range 10-2 eV-4x102 MeV (BND-400) is presented. The library contains a seven-group system of data for neutrons of E>10.5 MeV and a standard 26-group system for neutrons with E10.5 MeV, and those for matching with the file of data for neutrons with E<10.5 MeV are briefly described. In the BND-400 complex there are subroutines, which allow one to calculate the cross sections for neutron interaction with nuclei of matter with the help of various methods and models as well as to calculate group cross sections. It also provides output files in the form convenient for work. A brief instruction for BND-400 explotation on the computer BESM-6 is given
Bierón, Jacek; Froese Fischer, Charlotte; Indelicato, Paul; Jönsson, Per; Pyykkö, Pekka
2009-01-01
The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the expectation values for the hyperfine splittings of the 5d96s2 2D3/2 and 5d96s2 2D5/2 levels of atomic gold. One-, two-, and three-body electron correlation effects involving all 79 electrons have been included in a systematic manner. The approximation employed in this study is equivalent to a Complete Active Space (CAS) approach. Calculated electric field gradients, together with experimental values of ...
Stoll, M.H C; Rommets, J.W.; H. J. W. de Baar
1993-01-01
During the 1989 and 1990 JGOFS North Atlantic Pilot Study a comparison was made between the Coulometric and the acid titration method for determination of total carbon dioxide (TCO2) in seawater. TCO2 and alkalinity have been calculated from acid titration using either the modified Gran plot or the curve-fitting routine. Depth profiles showed fair agreement (on average 0.6% or about 12.5 μmol l−1) between the TCO2 calculated from the acid titration method and the TCO2 measured independently b...
International Nuclear Information System (INIS)
Volume one contains calculations for: embankment design--embankment material properties; Union Carbide site--bedrock contours; vicinity properties--origin of contamination; North Continent and Union Carbide sites contaminated materials--excavation quantities; and demolition debris--quantity estimate
National Oceanic and Atmospheric Administration, Department of Commerce — The dataset consists of calculated annual and monthly mean ocean volume transport stream function on 1 degree resolution using the WOA13 (T, S) and corresponding...
Energy Technology Data Exchange (ETDEWEB)
Santos, Cesar A.G.; Correa, Jorge E. [Para Univ., Belem (Brazil). Centro Tecnologico. Dept. de Engenharia Mecanica]. E-mails: gsantos@ufpa.br; jecorrea@amazon.com.br
2000-07-01
This work performs a comparative analysis among the constant and variable air volume multi zones acclimation systems, used for provide the thermal comfort in buildings. The work used the simulation HVAC2KIT computer program. The results of sensible and latent heats transfer rates on the cooling and dehumidification, inflating fan capacity, and heat transfer on the final heating condenser were obtained and analysed for the climate conditions of the Brazilian city of Belem from Para State, presenting hot and humid climate during all the year.
A method of calculating a lung clinical target volume DVH for IMRT with intrafractional motion.
Kung, J H; Zygmanski, P; Choi, N; Chen, G T Y
2003-06-01
The motion of lung tumors from respiration has been reported in the literature to be as large as 1-2 cm. This motion requires an additional margin between the Clinical Target Volume (CTV) and the Planning Target Volume (PTV). In Intensity Modulated Radiotherapy (IMRT), while such a margin is necessary, the margin may not be sufficient to avoid unintended high and low dose regions to the interior on moving CTV. Gated treatment has been proposed to improve normal tissues sparing as well as to ensure accurate dose coverage of the tumor volume. The following questions have not been addressed in the literature: (a) what is the dose error to a target volume without a gated IMRT treatment? (b) What is an acceptable gating window for such a treatment. In this study, we address these questions by proposing a novel technique for calculating the three-dimensional (3-D) dose error that would result if a lung IMRT plan were delivered without a gated linac beam. The method is also generalized for gated treatment with an arbitrary triggering window. IMRT plans for three patients with lung tumors were studied. The treatment plans were generated with HELIOS for delivery with 6 MV on a CL2100 Varian linear accelerator with a 26 pair MLC. A CTV to PTV margin of 1 cm was used. An IMRT planning system searches for an optimized fluence map phi(x,y) for each port, which is then converted into a dynamic MLC file (DMLC). The DMLC file contains information about MLC subfield shapes and the fractional Monitor Units (MUs) to be delivered for each subfield. With a lung tumor, a CTV that executes a quasiperiodic motion z(t) does not receive phi(x,y), but rather an Effective Incident Fluence EIF(x,y). We numerically evaluate the EIF(x,y) from a given DMLC file by a coordinate transformation to the Target's Eye View (TEV). In the TEV coordinate system, the CTV itself is stationary, and the MLC is seen to execute a motion -z(t) that is superimposed on the DMLC motion. The resulting EIF(x,y) is
A method of calculating a lung clinical target volume DVH for IMRT with intrafractional motion
International Nuclear Information System (INIS)
The motion of lung tumors from respiration has been reported in the literature to be as large as 1-2 cm. This motion requires an additional margin between the Clinical Target Volume (CTV) and the Planning Target Volume (PTV). In Intensity Modulated Radiotherapy (IMRT), while such a margin is necessary, the margin may not be sufficient to avoid unintended high and low dose regions to the interior on moving CTV. Gated treatment has been proposed to improve normal tissues sparing as well as to ensure accurate dose coverage of the tumor volume. The following questions have not been addressed in the literature: (a) what is the dose error to a target volume without a gated IMRT treatment? (b) What is an acceptable gating window for such a treatment. In this study, we address these questions by proposing a novel technique for calculating the three-dimensional (3-D) dose error that would result if a lung IMRT plan were delivered without a gated linac beam. The method is also generalized for gated treatment with an arbitrary triggering window. IMRT plans for three patients with lung tumors were studied. The treatment plans were generated with HELIOS for delivery with 6 MV on a CL2100 Varian linear accelerator with a 26 pair MLC. A CTV to PTV margin of 1 cm was used. An IMRT planning system searches for an optimized fluence map Φ(x,y) for each port, which is then converted into a dynamic MLC file (DMLC). The DMLC file contains information about MLC subfield shapes and the fractional Monitor Units (MUs) to be delivered for each subfield. With a lung tumor, a CTV that executes a quasiperiodic motion z(t) does not receive Φ(x,y), but rather an Effective Incident Fluence EIF(x,y). We numerically evaluate the EIF(x,y) from a given DMLC file by a coordinate transformation to the Target's Eye View (TEV). In the TEV coordinate system, the CTV itself is stationary, and the MLC is seen to execute a motion -z(t) that is superimposed on the DMLC motion. The resulting EIF(x,y) is input
Exact calculation of the overlap volume of spheres and mesh elements
Strobl, Severin; Formella, Arno; Pöschel, Thorsten
2016-04-01
An algorithm for the exact calculation of the overlap volume of a sphere and a tetrahedron, wedge, or hexahedron is described. The method can be used to determine the exact local solid fractions for a system of spherical, non-overlapping particles contained in a complex mesh, a question of significant relevance for the numerical solution of many fluid-solid interaction problems. While challenging due to the limited machine precision, a numerically robust version of the calculation maintaining high computational efficiency is devised. The method is evaluated with respect to the numerical precision and computational cost. It is shown that the exact calculation is only limited by the machine precision and can be applied to a wide range of size ratios, contrary to previously published methods. Eliminating this constraint enables the usage of meshes with higher resolution near the system boundaries for coupled CFD-DEM simulations. The numerical robustness is further illustrated by applying the method to highly deformed mesh elements. The full source code of the reference implementation is made available under an open-source license.
International Nuclear Information System (INIS)
This report (vol. 8) presents graphs of supplemental neutron-induced cross sections in the Experimental Cross Section Information Library (ECSIL) as of July 4, 1976. It consists of interactions where more than one data set is needed to show cross-section behavior. In contrast, vol. 7 of this UCRL-50400 series consists primarily of interactions where a single data set contains enough points to show cross-section behavior. Vol. 7 contains total, elastic, capture, and fission cross sections (along with the parameters anti ν, α, and eta). Volume 8 contains all other reactions. Data are plotted with associated cross-section error bars (when given) and compared with the Evaluated Nuclear Data Library (ENDL) as of July 4, 1976. The plots are arranged in ascending order of atomic number (Z) and atomic weight (A). Part A contains the plots for Z = 1 to 35; Part B contains the plots for Z greater than 35
International Nuclear Information System (INIS)
Highlights: • ΔG and Keq for NO2 dimerization and NH3 synthesis calculated via ab-initio methods. • Vis-á-vis experiments, W1 and CCSD(T) are accurate and G3B3 also does quite well. • CBS-APNO most accurate for NH3 reaction but shows limitations in modeling NO2. • Temperature dependence of ΔG and Keq is calculated for the NH3 reaction. • Good agreement of calculated Keq with experiments and the van’t Hoff approximation. -- Abstract: Standard quantum chemical methods are used for accurate calculation of thermochemical properties such as enthalpies of formation, entropies and Gibbs energies of formation. Equilibrium reactions are widely investigated and experimental measurements often lead to a range of reaction Gibbs energies and equilibrium constants. It is useful to calculate these equilibrium properties from quantum chemical methods in order to address the experimental differences. Furthermore, most standard calculation methods differ in accuracy and feasibility of the system size. Hence, a systematic comparison of equilibrium properties calculated with different numerical algorithms would provide a useful reference. We select two well-known gas phase equilibrium reactions with small molecules: covalent dimer formation of NO2 (2NO2 ⇌ N2O4) and the synthesis of NH3 (N2 + 3 H2 ⇌ 2NH3). We test four quantum chemical methods denoted by G3B3, CBS-APNO, W1 and CCSD(T) with aug-cc-pVXZ basis sets (X = 2, 3, and 4), to obtain thermochemical data for NO2, N2O4, and NH3. The calculated standard formation Gibbs energies ΔfG° are used to calculate standard reaction Gibbs energies ΔrG° and standard equilibrium constants Keq for the two reactions. Standard formation enthalpies ΔfH° are calculated in a more reliable way using high-level methods such as W1 and CCSD(T). Standard entropies S° for the molecules are calculated well within the range of experiments for all methods, however, the values of standard formation Gibbs energies ΔfG° show some
Slavinić, Petra; Cvetković, Marko
2016-01-01
The volume calculation of geological structures is one of the primary goals of interest when dealing with exploration or production of oil and gas in general. Most of those calculations are done using advanced software packages but still the mathematical workflow (equations) has to be used and understood for the initial volume calculation process. In this paper a comparison is given between bulk volume calculations of geological structures using trapezoidal and Simpson's rule and the ones obtained from cell-based models. Comparison in calculation is illustrated with four models; dome - 1/2 of ball/sphere, elongated anticline, stratigraphic trap due to lateral facies change and faulted anticline trap. Results show that Simpson's and trapezoidal rules give a very accurate volume calculation even with a few inputs(isopach areas - ordinates). A test of cell based model volume calculation precision against grid resolution is presented for various cases. For high accuracy, less the 1% of an error from coarsening, a cell area has to be 0.0008% of the reservoir area
Matching Excluded Volume Hadron Resonance Gas Models and Perturbative QCD to Lattice Calculations
Albright, M; Young, C
2014-01-01
We match three hadronic equations of state at low energy densities to a perturbatively computed equation of state of quarks and gluons at high energy densities. One of them includes all known hadrons treated as point particles, which approximates attractive interactions among hadrons. The other two include, in addition, repulsive interactions in the form of excluded volumes occupied by the hadrons. A switching function is employed to make the crossover transition from one phase to another without introducing a thermodynamic phase transition. A chi-square fit to accurate lattice calculations with temperature $100 < T < 1000$ MeV determines the parameters. These parameters quantify the behavior of the QCD running gauge coupling and the hard core radius of protons and neutrons, which turns out to be $0.62 \\pm 0.04$ fm. The most physically reasonable models include the excluded volume effect. Not only do they include the effects of attractive and repulsive interactions among hadrons, but they also achieve b...
Harbers, Jasper V; Huijbregts, Mark A J; Posthuma, Leo; Van de Meent, Dik
2006-03-01
Although many chemicals are in use, the environmental impacts of only a few have been established, usually on per-chemical basis. Uncertainty remains about the overall impact of chemicals. This paper estimates combined toxic pressure on coastal North Sea ecosystems from 343 high-production-volume chemicals used within the catchment of rivers Rhine, Meuse, and Scheldt. Multimedia fate modeling and species sensitivity distribution-based effects estimation are applied. Calculations start from production volumes and emission rates and use physicochemical substance properties and aquatic ecotoxicity data. Parameter uncertainty is addressed by Monte Carlo simulations. Results suggest that the procedure is technically feasible. Combined toxic pressure of all 343 chemicals in coastal North Seawater is 0.025 (2.5% of the species are exposed to concentration levels above EC50 values), with a wide confidence interval of nearly 0-1. This uncertainty appears to be largely due to uncertainties in interspecies variances of aquatic toxicities and, to a lesser extent, to uncertainties in emissions and degradation rates. Due to these uncertainties, the results support gross ranking of chemicals in categories: negligible and possibly relevant contributions only. With 95% confidence, 283 of the 343 chemicals (83%) contribute negligibly (less than 0.1%) to overall toxic pressure, and only 60 (17%) need further consideration. PMID:16568772
Institute of Scientific and Technical Information of China (English)
张敏革; 张吕鸿; 姜斌; 尹玉国; 李鑫钢
2008-01-01
Using the multiple reference frames(MRF)impeller method,the three-dimensional non-Newtonian flow field generated by a double helical ribbon(DHR)impeller has been simulated.The velocity field calculated by thc numerical simulation was similar to the previous studies and the power constant agreed well with the experi-mental data.Three computational fluid dynamic(CFD)methods,labeled Ⅰ,Ⅱ and Ⅲ,were used to compute the Metzner constant ks.The results showed that the calculated value from the slop method(method I)was consistent with the experimental data.Method Ⅱ.which took the maximal circumference-average shear rate around the impel-ler as the effective shear rate to compute ks,also showed good agreement with the experiment.However,both methods SUgcr from the complexity of calculation procedures.A new method(method III)was devised in this papcr to use the area.weighted average viscosity around the impeller as the effective viscosity for calculating ks.Method Ⅲ showed both good accuracy and ease of use.
Sasmal, Sudip; Nayak, Malaya K; Vaval, Nayana; Pal, Sourav
2015-01-01
The effective electric field experienced by the unpaired electron in the ground state of PbF, which is a potential candidate in the search of electron electric dipole moment due to some special characteristics, is calculated using Z-vector method in the coupled cluster single- and double- excitation approximation with four component Dirac spinor. This is an important quantity to set the upper bound limit of the electron electric dipole moment. Further, we have calculated molecular dipole moment and parallel magnetic hyperfine structure constant (A$_\\|$) of $^{207}$Pb in PbF to test the accuracy of the wave function obtained in the Z-vector method. The outcome of our calculations clearly suggests that the core electrons have significant contribution to the "atom in compound (AIC)" properties.
Sasmal, Sudip; Pathak, Himadri; Nayak, Malaya K; Vaval, Nayana; Pal, Sourav
2015-08-28
The effective electric field experienced by the unpaired electron in the ground state of PbF, which is a potential candidate in the search of electron electric dipole moment due to some special characteristics, is calculated using Z-vector method in the coupled cluster single- and double- excitation approximation with four component Dirac spinor. This is an important quantity to set the upper bound limit of the electron electric dipole moment. Further, we have calculated molecular dipole moment and parallel magnetic hyperfine structure constant (A‖) of (207)Pb in PbF to test the accuracy of the wavefunction obtained in the Z-vector method. The outcome of our calculations clearly suggests that the core electrons have significant contribution to the "atom in compound" properties. PMID:26328830
Rhodes, Charles Kirkham
2010-01-01
The fine-structure constant {\\alpha}, the dimensionless number that represents the strength of electromagnetic coupling in the limit of sufficiently low energy interactions, is the crucial fundamental physical parameter that governs a nearly limitless range of phenomena involving the interaction of radiation with materials. Ideally, the apparatus of physical theory should be competent to provide a calculational procedure that yields a quantitatively correct value for {\\alpha} and the physical basis for its computation. This study presents the first demonstration of an observationally anchored theoretical procedure that predicts a unique value for {\\alpha} that stands in full agreement with the best (~370 ppt) high-precision experimental determinations. In a directly connected cryptographic computation, the method that gives these results also yields the magnitude of the cosmological constant {\\Omega}{\\Lambda} in conformance with the observational data and the condition of perfect flatness ({\\Omega}{\\Lambda} +...
International Nuclear Information System (INIS)
A method is presented for the calculation of association constants and the concentration of binding sites in a reaction of a ligand with a heterogeneous system of binding sites. The Scatchard plot for such a system is curvelinear and the method employs previously established relationships between the parameters of the limiting slopes to such a curve and the above mentioned association constants and concentrations of binding sites. The special case of a system with two different and non-interacting groups of binding sites was solved. The expressions thus obtained were used to characterize the reaction of a polypeptide neurotoxin with its specific binding sites in a membranal preparation from insect central nervous system. Moreover it is evident from these expressions that the widely accepted method to analyze such system, by an intuitive generalization of the method applicable to homogeneous systems, is erroneous and should be avoided. (author)
ZZ ORYX-E/38B, Group Constant Library from ENDF/B Fission Product Data for ORIGEN Calculation
International Nuclear Information System (INIS)
1 - Nature of physical problem solved: Format: ORIGEN; Number of groups: 124 energy groups; Nuclides: H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po. Origin: ENDF/B-IV; Weighting spectrum: Maxwellian (1/E) fission spectrum with a one percent tolerance. ORYX-E increases the versatility of the program ORIGEN , the isotope generation and depletion code package by providing basic cross section and decay information for light element, fission-product, and actinide nuclides. This data library package results from data compiled for ORNL Chemical Technology Division's work with ORIGEN and from a 2-year effort of the cross section evaluation working group (CSEWG) fission product task force. 2 - Method of solution: The data is generated from ENDF/B-IV and is formatted for input to the ORIGEN code. Applications include calculations for waste projection, decay heat, nuclear safeguards, and fuel cycle economics. The data library is generated from the ENDF/B-IV fission product data. The capture cross section of all fission product nuclides for which capture cross section information is given (about 180 nuclides) were processed into 124 energy groups using MINX. Multigroup cross sections were generated at 0 degrees with infinite dilution and one broad thermal group. Fine group data was generated using a Maxwellian (1/E) fission spectrum with a one percent tolerance
Jing, Wei
2013-09-02
This work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2
Xie, Hongzhan; Song, Lanbo; Xie, Yizhi; Pi, Dong; Shao, Chunyu; Lin, Qizhao
2015-01-01
The objective of this study was to investigate the macroscopic spray characteristics of different 0%–100% blends of biodiesel derived from drainage oil and diesel (BD0, BD20, BD50, BD80, BD100), such as spray tip penetration, average tip velocity at penetration, spray angle, average spray angle, spray evolution process, spray area and spray volume under different injection pressures (60, 70, 80, 90, 100 MPa) and ambient pressures (0.1, 0.3, 0.5, 0.7, 0.9 MPa) using a common rail system equipp...
Hongzhan Xie; Lanbo Song; Yizhi Xie; Dong Pi; Chunyu Shao; Qizhao Lin
2015-01-01
The objective of this study was to investigate the macroscopic spray characteristics of different 0%â€“100% blends of biodiesel derived from drainage oil and diesel (BD0, BD20, BD50, BD80, BD100), such as spray tip penetration, average tip velocity at penetration, spray angle, average spray angle, spray evolution process, spray area and spray volume under different injection pressures (60, 70, 80, 90, 100 MPa) and ambient pressures (0.1, 0.3, 0.5, 0.7, 0.9 MPa) using a common rail system equi...
Min, Stephen K; Samaranayake, Chaminda P; Sastry, Sudhir K
2011-05-26
Direct measurements of reaction volume, so far, have been limited to atmospheric pressure. This study describes a method for in situ reaction volume measurements under pressure using a variable volume piezometer. Reaction volumes for protonic ionization of weak acid buffering agents (MES, citric acid, sulfanilic acid, and phosphoric acid) were measured in situ under pressure up to 400 MPa at 25 °C. The methodology involved initial separation of buffering agents within the piezometer using gelatin capsules. Under pressure, the volume of the reactants was measured at 25 °C, and the contents were heated to 40 °C to dissolve the gelatin and allow the reaction to occur, and cooled to 25 °C, where the volume of products was measured. Reaction volumes were used to calculate pH of the buffer solutions as a function of pressure. The results show that the measured reaction volumes as well as the calculated pH values generally quite agree with their respective theoretically predicted values up to 100 MPa. The results of this study highlight the need for a comprehensive theory to describe the pressure behavior of ionization reactions in realistic systems especially at higher pressures. PMID:21542618
Institute of Scientific and Technical Information of China (English)
Liu Yu-Fang; Sun Jin-Feng; Ma Heng; Zhu Zun-Lue
2007-01-01
The accurate dissociation energy and harmonic frequency for the highly excited 21 Πu state of dimer 7Li2 have been calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space.The calculated results are in excellent agreement with experimental measurements.The potential energy curves at numerous basis sets for this state are obtained over a wide internuclear separation range from about 2.4ao to 37.0ao.And the conclusion is gained that the basis set 6-311++G(d,p) is a most suitable one.The calculated spectroscopic constants De,Re,ωe,ωeχe,αe and Be at 6-311++G(d,p) are 0.9670 eV,0.3125 nm,238.6 cm-1,1.3705cm-1,0.0039 cm-1 and 0.4921 cm-1.respectively.The vibrational levels are calculated by solving the radial Schr(o)dinger equation of nuclear motion.A total of 53 vibrational levels are found and reported for the first time.The classical turning points have been computed.Comparing with the measurements,in which only the first nine vibrational levels have been obtained so far,the present calculations are very encouraging.A careful comparison of the present results of the parameters De and ωe with those obtained from previous theories clearly shows that the present calculations are much closer to the measurements than previous theoretical results,thus representing an improvement on the accuracy of the ab initio calculations of the potentials for this state.
Energy Technology Data Exchange (ETDEWEB)
Zarycz, M. Natalia C., E-mail: mnzarycz@gmail.com; Provasi, Patricio F., E-mail: patricio@unne.edu.ar [Department of Physics, University of Northeastern - CONICET, Av. Libertad 5500, Corrientes W3404AAS (Argentina); Sauer, Stephan P. A., E-mail: sauer@kiku.dk [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark)
2015-12-28
It is investigated, whether the number of excited (pseudo)states can be truncated in the sum-over-states expression for indirect spin-spin coupling constants (SSCCs), which is used in the Contributions from Localized Orbitals within the Polarization Propagator Approach and Inner Projections of the Polarization Propagator (IPPP-CLOPPA) approach to analyzing SSCCs in terms of localized orbitals. As a test set we have studied the nine simple compounds, CH{sub 4}, NH{sub 3}, H{sub 2}O, SiH{sub 4}, PH{sub 3}, SH{sub 2}, C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}. The excited (pseudo)states were obtained from time-dependent density functional theory (TD-DFT) calculations with the B3LYP exchange-correlation functional and the specialized core-property basis set, aug-cc-pVTZ-J. We investigated both how the calculated coupling constants depend on the number of (pseudo)states included in the summation and whether the summation can be truncated in a systematic way at a smaller number of states and extrapolated to the total number of (pseudo)states for the given one-electron basis set. We find that this is possible and that for some of the couplings it is sufficient to include only about 30% of the excited (pseudo)states.
International Nuclear Information System (INIS)
It is investigated, whether the number of excited (pseudo)states can be truncated in the sum-over-states expression for indirect spin-spin coupling constants (SSCCs), which is used in the Contributions from Localized Orbitals within the Polarization Propagator Approach and Inner Projections of the Polarization Propagator (IPPP-CLOPPA) approach to analyzing SSCCs in terms of localized orbitals. As a test set we have studied the nine simple compounds, CH4, NH3, H2O, SiH4, PH3, SH2, C2H2, C2H4, and C2H6. The excited (pseudo)states were obtained from time-dependent density functional theory (TD-DFT) calculations with the B3LYP exchange-correlation functional and the specialized core-property basis set, aug-cc-pVTZ-J. We investigated both how the calculated coupling constants depend on the number of (pseudo)states included in the summation and whether the summation can be truncated in a systematic way at a smaller number of states and extrapolated to the total number of (pseudo)states for the given one-electron basis set. We find that this is possible and that for some of the couplings it is sufficient to include only about 30% of the excited (pseudo)states
Greives, Nicholas; Zhou, Huan-Xiang
2012-10-01
A method developed by Northrup et al. [J. Chem. Phys. 80, 1517 (1984)], 10.1063/1.446900 for calculating protein-ligand binding rate constants (ka) from Brownian dynamics (BD) simulations has been widely used for rigid molecules. Application to flexible molecules is limited by the formidable computational cost to treat conformational fluctuations during the long BD simulations necessary for ka calculation. Here, we propose a new method called BDflex for ka calculation that circumvents this problem. The basic idea is to separate the whole space into an outer region and an inner region, and formulate ka as the product of kE and bar η _d, which are obtained by separately solving exterior and interior problems. kE is the diffusion-controlled rate constant for the ligand in the outer region to reach the dividing surface between the outer and inner regions; in this exterior problem conformational fluctuations can be neglected. bar η _d is the probability that the ligand, starting from the dividing surface, will react at the binding site rather than escape to infinity. The crucial step in reducing the determination of bar η _d to a problem confined to the inner region is a radiation boundary condition imposed on the dividing surface; the reactivity on this boundary is proportional to kE. By confining the ligand to the inner region and imposing the radiation boundary condition, we avoid multiple-crossing of the dividing surface before reaction at the binding site and hence dramatically cut down the total simulation time, making the treatment of conformational fluctuations affordable. BDflex is expected to have wide applications in problems where conformational fluctuations of the molecules are crucial for productive ligand binding, such as in cases where transient widening of a bottleneck allows the ligand to access the binding pocket, or the binding site is properly formed only after ligand entrance induces the closure of a lid.
Energy Technology Data Exchange (ETDEWEB)
Gomez-Tenedor Alonso, S.; Rincon Perez, M.; Penedo Cobos, J. M.; Garcia Castejon, M. A.
2011-07-01
The discrepancies in the calculation of the same volume between different planning systems impact on dose-volume histograms and therefore clinical assessment of dosimetry for patients. The transfer, by a local network, tomographic study (CT) and contours of critical organs of patients, between our two planning systems allows us to evaluate the calculation of identical volumes.
Rusakova, Irina L; Rusakov, Yury Yu; Krivdin, Leonid B
2016-06-01
This work reports on the comprehensive calculation of the NMR one-bond spin-spin coupling constants (SSCCs) involving carbon and tellurium, (1) J((125) Te,(13) C), in four representative compounds: Te(CH3 )2 , Te(CF3 )2 , Te(CCH)2 , and tellurophene. A high-level computational treatment of (1) J((125) Te,(13) C) included calculations at the SOPPA level taking into account relativistic effects evaluated at the 4-component RPA and DFT levels of theory, vibrational corrections, and solvent effects. The consistency of different computational approaches including the level of theory of the geometry optimization of tellurium-containing compounds, basis sets, and methods used for obtainig spin-spin coupling values have also been discussed in view of reproducing the experimental values of the tellurium-carbon SSCCs. Relativistic corrections were found to play a major role in the calculation of (1) J((125) Te,(13) C) reaching as much as almost 50% of the total value of (1) J((125) Te,(13) C) while relativistic geometrical effects are of minor importance. The vibrational and solvent corrections account for accordingly about 3-6% and 0-4% of the total value. It is shown that taking into account relativistic corrections, vibrational corrections and solvent effects at the DFT level essentially improves the agreement of the non-relativistic theoretical SOPPA results with experiment. © 2016 Wiley Periodicals, Inc. PMID:26931355
International Nuclear Information System (INIS)
Volume four contains calculations for: Borrow areas--site evaluation; temporary facilities--material quantities; embankment quantities--excavation and cover materials; Burro Canyon site excavation quantities--rippable and unrippable materials; site restoration--earthwork quantities and seeding; and bid schedule quantities and material balance
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-09-01
Volume two contains calculations for: embankment design--slope stability analysis; embankment design--excavation stability; embankment design--settlement and cover cracking analysis; radon barrier design--statistical analysis of ra-226 concentrations for North Continent and Union Carbide sites; radon barrier design--RAECOM input data; radon barrier design--design thickness; and cover design--frost penetration depth.
International Nuclear Information System (INIS)
Volume two contains calculations for: embankment design--slope stability analysis; embankment design--excavation stability; embankment design--settlement and cover cracking analysis; radon barrier design--statistical analysis of ra-226 concentrations for North Continent and Union Carbide sites; radon barrier design--RAECOM input data; radon barrier design--design thickness; and cover design--frost penetration depth
Energy Technology Data Exchange (ETDEWEB)
Yoshizaki, T.; Imanishi, H.; Nishida, K.; Yamashita, H.; Hiroyasu, H.; Kaneda, K. [Hiroshima University, Hiroshima (Japan)
1997-10-01
Three dimensional visualization technique based on volume rendering method has been developed in order to translate calculated results of diesel combustion simulation into realistically spray and flame images. This paper presents an overview of diesel combustion model which has been developed at Hiroshima University, a description of the three dimensional visualization technique, and some examples of spray and flame image generated by this visualization technique. 8 refs., 8 figs., 1 tab.
40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?
2010-07-01
..., or the transmix blended into gasoline by a transmix blender, under 40 CFR 80.84. ... gasoline volume for a refiner, blender, or importer for a given year, GVi, specified in paragraph (a) of... the RFS program under § 80.1143. (6) For blenders, the volume of finished gasoline, RBOB, or CBOB...
Energy Technology Data Exchange (ETDEWEB)
Papp, P., E-mail: papp@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Matejčík, Š. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Mach, P.; Urban, J. [Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 84248 Bratislava (Slovakia); Paidarová, I. [J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, CZ-182 23 Praha 8 (Czech Republic); Horáček, J., E-mail: horacek@mbox.troja.mff.cuni.cz [Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, CZ-180 00 Praha 8 (Czech Republic)
2013-06-03
Highlights: • The anions are stabilized by additional charges on the nuclei. • The energy dependence of anions and neutrals on nuclear charges are calculated by ab initio methods. • Resonance energies and widths are obtained from the energy data by analytical continuation with Padé approximation. • The resonance energies and widths of amino acids are compared with Nestmann–Peyerimhoff’s method and with experiment. • The resonance energies and (widths) of formic acid monomer and dimer are 2.09 (0.33) eV and 1.7 (0.13) eV, respectively. - Abstract: The method of analytic continuation in the coupling constant (ACCC) in combination with use of the statistical Padé approximation is applied to the determination of resonance energy and width of some amino acids and formic acid dimer. Standard quantum chemistry codes provide accurate data which can be used for analytic continuation in the coupling constant to obtain the resonance energy and width of organic molecules with a good accuracy. The obtained results are compared with the existing experimental ones.
Dossett, Jason; Ishak, M.; Rindler, W.; Moldenhauer, J.; Allison, C.
2008-05-01
Recently, Rindler and Ishak (2007) made a breakthrough in the field of gravitational lensing showing that a cosmological constant, Λ, will indeed contribute to the bending angle of light by a concentric mass, in fact, by decreasing it. Then Ishak et al. (2007) showed that the effect can be applied to observations of Einstein radii around clusters of galaxies. We present here various higher-order calculations and results for the bending angle and the Lambda contribution. Surprisingly, we find that the Lambda term is the next largest term after the Einstein first-order term for many cluster lens systems. For those lens systems, the Lambda contribution is larger than the second-order term and may be the next targeted term by future high precision experiments.
Wang, Wenji; Zhao, Yi
2012-12-01
Thermal rate constants for the title reaction are calculated by using the quantum instanton approximation within the full dimensional Cartesian coordinates. The results reveal that the quantum effect is remarkable for the reaction at both low and high temperatures, and the obtained rates are in good agreement with experimental measurements at high temperatures. Compared to the harmonic approximation, the torsional anharmonic effect of the internal rotation has a little influence on the rates at low temperatures, however, it enhances the rate by about 20% at 1000 K. In addition, the free energy barriers for the isotopic reactions and the temperature dependence of kinetic isotope effects are also investigated. Generally speaking, for the title reaction, the replacement of OH with OD will reduce the free energy barrier, while substituting D for H (connected to C) will increase the free energy barrier.
Balankina, E. S.
2016-06-01
Analytical dependences of a volume's properties on the differences between the geometric structures of initial monosystems are obtained for binary systems simulated by a grain medium. The effect of microstructural parameter k (the ratio of volumes of molecules of mixed components) on the concentration behavior of the relative excess molar volume of different types of real binary solutions is analyzed. It is established that the contribution due to differences between the volumes of molecules and coefficients of the packing density of mixed components is ~80-100% for mutual solutions of n-alkanes and ~55-80% of the experimental value of the relative excess molar volume for water solutions of n-alcohols.
Lei, Xuanwei; Huang, Jihua; Chen, Shuhai; Zhao, Xingke
2016-06-01
The principle of the lever rule on the dilatation curve and its application to the corresponding differential dilatation curve were introduced in a nonoverlapped two-phase continuous cooling process. The lever rule was further expanded in the case of an overlapped two-phase process. The application of the expanded lever rule was based on the approximate symmetry treatment on the differential dilatation curve, which shows reasonably both on the theoretical calculation and in the experimental results. High-strength low-alloy steels were thermal simulated with Gleeble 3500. The transformed phase volume fractions in different cooling processes were calculated by the expanded lever rule and metallography analysis. The results showed the expanded lever rule could calculate reliable phase volume fractions as metallography analysis.
Postoperative lung volume calculated by chest computed tomography in patients with esophageal cancer
International Nuclear Information System (INIS)
It has been reported that, due to the severe surgical stress of thoracotomy, respiratory function after esophagectomy under thoracotomy worsened as late as a month after surgery. To investigate the mechanism of the reduction of the respiratory function, we utilized chest CT to analyze separately the changes in the lung volume of the thoracotomized side and the other side. Here, we reported the results of our comparative study of lung volume and respiratory function, which was performed by spirogram before esophagectomy and 6 months afterwards. We selected twenty-three patients who had undergone esophagectomy under right thoracotomy. Fourteen of the selectees received standard thoracotomy, while the other nine had the anterior serratus muscle and the latissimus dorsi muscle preserved. Total lung volume was found to have decreased from a preoperative value of 4077±674 ml (mean±SD) to a postoperative value of 3964±774 ml, and right-lung volume significantly decreased from 2229±397 to 2023±397 ml, while left-lung volume tended to increase. While right-lung volume in standard thoracotomy displayed a significant decrease from 2264±334 to 1949±424 ml, that in muscle-preserving thoracotomy showed almost no change. Spirogram revealed that vital capacity had decreased from 3574±601 to 2666±576 ml, and forced expiratory volume in the first second showed a significant decrease from 2680±500 to 2249±485 ml. Comparing the decreasing rate, the correlation coefficients between right-lung volume and % VC was 0.58. These results suggested that a change of lung volume in the thoracotomized side could play a role in the post-operative decrease of vital capacity and that muscle-preserving thoracotomy might induce less surgical stress than standard thoracotomy. (author)
Postoperative lung volume calculated by chest computed tomography in patients with esophageal cancer
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Kiyotomi; Kitamura, Michihiko; Izumi, Keiichi; Suzuki, Hiroyuki; Minamiya, Yoshihiro; Saito, Reijiro; Ogawa, Junichi [Akita Univ. (Japan). School of Medicine
1999-05-01
It has been reported that, due to the severe surgical stress of thoracotomy, respiratory function after esophagectomy under thoracotomy worsened as late as a month after surgery. To investigate the mechanism of the reduction of the respiratory function, we utilized chest CT to analyze separately the changes in the lung volume of the thoracotomized side and the other side. Here, we reported the results of our comparative study of lung volume and respiratory function, which was performed by spirogram before esophagectomy and 6 months afterwards. We selected twenty-three patients who had undergone esophagectomy under right thoracotomy. Fourteen of the selectees received standard thoracotomy, while the other nine had the anterior serratus muscle and the latissimus dorsi muscle preserved. Total lung volume was found to have decreased from a preoperative value of 4077{+-}674 ml (mean{+-}SD) to a postoperative value of 3964{+-}774 ml, and right-lung volume significantly decreased from 2229{+-}397 to 2023{+-}397 ml, while left-lung volume tended to increase. While right-lung volume in standard thoracotomy displayed a significant decrease from 2264{+-}334 to 1949{+-}424 ml, that in muscle-preserving thoracotomy showed almost no change. Spirogram revealed that vital capacity had decreased from 3574{+-}601 to 2666{+-}576 ml, and forced expiratory volume in the first second showed a significant decrease from 2680{+-}500 to 2249{+-}485 ml. Comparing the decreasing rate, the correlation coefficients between right-lung volume and % VC was 0.58. These results suggested that a change of lung volume in the thoracotomized side could play a role in the post-operative decrease of vital capacity and that muscle-preserving thoracotomy might induce less surgical stress than standard thoracotomy. (author)
International Nuclear Information System (INIS)
Volume three contains calculations for: site hydrology--rainfall intensity, duration, and frequency relations; site hydrology-- probable maximum precipitation; erosion protection--rock quality evaluation; erosion protection--embankment top and side slope; erosion protection--embankment toe apron; erosion protection-- gradations and layer thicknesses; Union Carbide site--temporary drainage ditch design; Union Carbide site--retention basin sediment volume; Union Carbide site--retention basin sizing; Burro Canyon site temporary drainage--temporary drainage facilities; and Union Carbide site temporary drainage--water balance
Directory of Open Access Journals (Sweden)
Guez F.
2006-11-01
Full Text Available La recherche des conditions optimales d'exploitation d'un gisement fissuré repose sur une bonne description de la fissuration. En conséquence il est nécessaire de définir les dimensions et volumes des blocs matriciels en chaque point d'une structure. Or la géométrie du milieu (juxtaposition et formes des blocs est généralement trop complexe pour se prêter au calcul. Aussi, dans une précédente communication, avons-nous dû tourner cette difficulté par un raisonnement sur des moyennes (pendages, azimuts, espacement des fissures qui nous a conduits à un ordre de grandeur des volumes. Cependant un volume moyen ne peut pas rendre compte d'une loi de répartition des volumes des blocs. Or c'est cette répartition qui conditionne le choix d'une ou plusieurs méthodes successives de récupération. Aussi présentons-nous ici une méthode originale de calcul statistique de la loi de distribution des volumes des blocs matriciels, applicable en tout point d'un gisement. La part de gisement concernée par les blocs de volume donné en est déduite. La connaissance générale du phénomène de la fracturation sert de base au modèle. Les observations de subsurface sur la fracturation du gisement en fournissent les données (histogramme d'orientation et d'espacement des fissures.Une application au gisement d'Eschau (Alsace, France est rapportée ici pour illustrer la méthode. The search for optimum production conditions for a fissured reservoir depends on having a good description of the fissure pattern. Hence the sizes and volumes of the matrix blocks must be defined at all points in a structure. However, the geometry of the medium (juxtaposition and shapes of blocks in usually too complex for such computation. This is why, in a previous paper, we got around this problem by reasoning on the bases of averages (clips, azimuths, fissure spacing, and thot led us to an order of magnitude of the volumes. Yet a mean volume cannot be used to explain
Fu, Yuwei; Rong, Mingzhe; Yang, Kang; Yang, Aijun; Wang, Xiaohua; Gao, Qingqing; Liu, Dingxin; Murphy, Anthony B.
2016-04-01
SF6 is widely used in electrical equipment as an insulating gas. In the presence of an electric arc, partial discharge (PD) or spark, SF6 dissociation products (such as SF2, SF3 and SF4) react with the unavoidable gas impurities (such as water vapor and oxygen), electrodes and surrounding solid insulation materials, forming several toxic and corrosive byproducts. The main stable decomposition products are SO2F, SO2F2 and SOF2, which have been confirmed experimentally to have a direct relationship with discharge faults, and are thus expected to be useful in the fault diagnosis of power equipment. Various studies have been performed of the main SF6 decomposition species and their concentrations under different types of faults. However, most of the experiments focused on the qualitative analysis of the relationship between the stable products and discharge faults. Although some theoretical research on the formation of main SF6 derivatives have been carried out using chemical kinetics models, the basic data (chemical reactions and their rate constants) adopted in the model are inaccurate and incomplete. The complex chemical reactions of SF6 with the impurities are ignored in most cases. The rate constants of some reactions obtained at ambient temperature or in a narrow temperature range are adopted in the models over a far greater range, for example up to 12 000 K, due to the difficulty in the experimental measurement and theoretical estimation of rate coefficients, particularly at high temperatures. Therefore, improved theoretical models require not only the consideration of additional SF6 decomposition reactions in the presence of impurities but also on improved values of rate constants. This paper is devoted to determining the rate constants of the chemical reactions relating to the main byproducts of SF6 decomposition in SF6 gas-insulated power equipment: SO2F, SOF2 and SO2F2. Quantum chemistry calculations with density functional theory, conventional
Project W-320, 241-C-106 sluicing: Piping calculations. Volume 8
International Nuclear Information System (INIS)
This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the hydraulic analysis on the slurry line and the supernate line for W-320. This calculation will use the As-Built conditions of the slurry line and the supernate line. Booster Pump Curves vs System Curves shall be generated for the supernate system and the slurry system
The cosmological constant and black-hole thermodynamic potentials
Dolan, Brian P.
2011-01-01
Abstract The thermodynamics of black holes in various dimensions are described in the presence of a negative cosmological constant which is treated as a thermodynamic variable, interpreted as a pressure in the equation of state. The black hole mass is then identified with the enthalpy, rather than the internal energy, and heat capacities are calculated at constant pressure not at constant volume. The Euclidean action is associated with a bridge equation for the Gibbs free energy and not th...
Institute of Scientific and Technical Information of China (English)
S. C. Choi; D. I. Jung; C. H. Won; J. M. Rim
2006-01-01
The authors discovered large differences in the characteristics of overflows by the calculation of 1) intercepting volume of overflows for sewer systems using SWMM model which takes into consideration the runoff and pollutants from rainfalls and 2) the intercepted volume in the total flow at an investigation site. The intercepting rate at the investigation point of CSOs showed higher values than the SSDs. Based on the modeling of the receiving water quality after calculating the intercepting amount of overflows by considering the characteristics of outflows for a proper management of the overflow of sewer systems with rainfalls, it is clear that the BOD decreased by 82.9%-94.0% for the discharge after intercepting a specific amount of flows compared to the discharge from unprocessed overflows.
Project W-320, 241-C-106 sluicing HVAC calculations, Volume 4
Energy Technology Data Exchange (ETDEWEB)
Bailey, J.W.
1998-07-30
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. The report contains the following design calculations: Cooling load in pump pit 241-AY-102; Pressure relief seal loop design; Process building piping stress analysis; Exhaust skid maximum allowable leakage criteria; and Recirculation heat, N509 duct requirements.
Project W-320, 241-C-106 sluicing HVAC calculations, Volume 4
International Nuclear Information System (INIS)
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. The report contains the following design calculations: Cooling load in pump pit 241-AY-102; Pressure relief seal loop design; Process building piping stress analysis; Exhaust skid maximum allowable leakage criteria; and Recirculation heat, N509 duct requirements
International Nuclear Information System (INIS)
The objective of this study is to investigate the changes observed in the absorbed doses in mammary gland tissue when irradiated with a equipment of high dose rate known as Mammosite and introducing material resources contrary to the tissue that constitutes the mammary gland. The modeling study is performed with the code MCNPX, 2005 version, the equipment and the mammary gland and calculating the absorbed doses in tissue when introduced small volumes of air or calcium in the system. (Author)
Volume fraction calculation in multiphase system such as oil-water-gas using neutron
International Nuclear Information System (INIS)
Multi-phase flows are common in diverse industrial sectors and the attainment of the volume fraction of each element that composes the flow system presents difficulties for the engineering process, therefore, to determine them is very important. In this work is presented methodology for determination of volume fractions in annular three-phase flow systems, such as oil-water-gas, based on the use of nuclear techniques and artificial intelligence. Using the principle of the fast-neutron transmission/scattering, come from an isotopic 241Am-Be source, and two point detectors, is gotten measured that they are influenced by the variations of the volume fractions of each phase present in the flow. An artificial neural network is trained to correlate such measures with the respective volume fractions. In order to get the data for training of the artificial neural network without necessity to carry through experiments, MCNP-X code is used, that simulates computational of the neutrons transport. The methodology is sufficiently advantageous, therefore, allows to develop a measurement system capable to determine the fractions of the phases (oil-water-gas), with proper requirements of each petroliferous installation and with national technology contributing, possibly, with reduction of costs and increase of productivity. (author)
Project W-320, 241-C-106 sluicing HVAC calculations, Volume 1
Energy Technology Data Exchange (ETDEWEB)
Bailey, J.W.
1998-08-07
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. The report contains the following calculations: Exhaust airflow sizing for Tank 241-C-106; Equipment sizing and selection recirculation fan; Sizing high efficiency mist eliminator; Sizing electric heating coil; Equipment sizing and selection of recirculation condenser; Chiller skid system sizing and selection; High efficiency metal filter shielding input and flushing frequency; and Exhaust skid stack sizing and fan sizing.
Project W-320, 241-C-106 sluicing HVAC calculations, Volume 1
International Nuclear Information System (INIS)
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. The report contains the following calculations: Exhaust airflow sizing for Tank 241-C-106; Equipment sizing and selection recirculation fan; Sizing high efficiency mist eliminator; Sizing electric heating coil; Equipment sizing and selection of recirculation condenser; Chiller skid system sizing and selection; High efficiency metal filter shielding input and flushing frequency; and Exhaust skid stack sizing and fan sizing
Project W-320, 241-C-106 sluicing: Piping calculations. Volume 4
International Nuclear Information System (INIS)
This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the structural analysis of the Pipe Supports designed for Slurry and Supernate transfer pipe lines in order to meet the requirements of applicable ASME codes. The pipe support design loads are obtained from the piping stress calculations W320-27-I-4 and W320-27-I-5. These loads are the total summation of the gravity, pressure, thermal and seismic loads. Since standard typical designs are used for each type of pipe support such as Y-Stop, Guide and Anchors, each type of support is evaluated for the maximum loads to which this type of supports are subjected. These loads are obtained from the AutoPipe analysis and used to check the structural adequacy of these supports
Project W-320, 241-C-106 sluicing: Piping calculations. Volume 4
Energy Technology Data Exchange (ETDEWEB)
Bailey, J.W.
1998-07-24
This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the structural analysis of the Pipe Supports designed for Slurry and Supernate transfer pipe lines in order to meet the requirements of applicable ASME codes. The pipe support design loads are obtained from the piping stress calculations W320-27-I-4 and W320-27-I-5. These loads are the total summation of the gravity, pressure, thermal and seismic loads. Since standard typical designs are used for each type of pipe support such as Y-Stop, Guide and Anchors, each type of support is evaluated for the maximum loads to which this type of supports are subjected. These loads are obtained from the AutoPipe analysis and used to check the structural adequacy of these supports.
Project W-320, 241-C-106 sluicing piping calculations, Volume 7
International Nuclear Information System (INIS)
The object of this report is to calculate the hydraulic forces imposed at the sluicer nozzle. This is required by Project W-320 waste retrieval for tank 241-C-106. The method of analysis used is Bernoulli's momentum equation for stead flow
Project W-320, 241-C-106 sluicing piping calculations, Volume 7
Energy Technology Data Exchange (ETDEWEB)
Bailey, J.W.
1998-07-29
The object of this report is to calculate the hydraulic forces imposed at the sluicer nozzle. This is required by Project W-320 waste retrieval for tank 241-C-106. The method of analysis used is Bernoulli`s momentum equation for stead flow.
[Cotyla quid? On the early history of late medieval medical volume calculations].
Bergmann, Axel
2005-01-01
As can be made evident chiefly by their comparative numerical examination, the Egyptian pyramids (the step pyramids being excluded for the present purpose) have been, from the beginning up to the Egyptian fashion in early Imperial Rome, designed and built with the additional intention of physically manifesting a volume of pi x 10k x (average value) 0.96824 cm3, where k is either a positive integer or zero, and where pi is a short product, following very restrictive formation rules which to some extent are traceable in the papyrus Rhind, of prime numbers. Conceptually (but not really as to the Hin at least) this establishes the capacity units 1 [2]Heqat = 9682.4 cm3 and 1 Hin = 484.12 cm3 already for the Old Kingdom. It is shown further that the Attic Medimnos as introduced in the course of finishing Solon's reforms is identical with the Egyptian volume system's standard unification: pisigma = 2 x 3 x 5 x 7 x 11 x 23, and k = 0, so that 1 Medimnos = about 51443 cm3. Accordingly and by means of some adjacent considerations a Kotyle / Cotyla of 269 cm3 +/- 1 cm3 is established for the Hellenistic, early Arabic, and Medieval Latin medicine. PMID:16425844
Project W-320, 241-C-106 sluicing electrical calculations, Volume 2
International Nuclear Information System (INIS)
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. These calculations are required: To determine the power requirements needed to power electrical heat tracing segments contained within three manufactured insulated tubing assemblies; To verify thermal adequacy of tubing assembly selection by others; To size the heat tracing feeder and branch circuit conductors and conduits; To size protective circuit breaker and fuses; and To accomplish thermal design for two electrical heat tracing segments: One at C-106 tank riser 7 (CCTV) and one at the exhaust hatchway (condensate drain). Contents include: C-Farm electrical heat tracing; Cable ampacity, lighting, conduit fill and voltage drop; and Control circuit sizing and voltage drop analysis for the seismic shutdown system
Project W-320, 241-C-106 sluicing electrical calculations, Volume 2
Energy Technology Data Exchange (ETDEWEB)
Bailey, J.W.
1998-08-07
This supporting document has been prepared to make the FDNW calculations for Project W-320, readily retrievable. These calculations are required: To determine the power requirements needed to power electrical heat tracing segments contained within three manufactured insulated tubing assemblies; To verify thermal adequacy of tubing assembly selection by others; To size the heat tracing feeder and branch circuit conductors and conduits; To size protective circuit breaker and fuses; and To accomplish thermal design for two electrical heat tracing segments: One at C-106 tank riser 7 (CCTV) and one at the exhaust hatchway (condensate drain). Contents include: C-Farm electrical heat tracing; Cable ampacity, lighting, conduit fill and voltage drop; and Control circuit sizing and voltage drop analysis for the seismic shutdown system.
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.
Calculated neutron KERMA factors based on the LLNL ENDL data file. Volume 27
International Nuclear Information System (INIS)
Neutron KERMA factors calculated from the LLNL ENDL data file are tabulated for 15 composite materials and for the isotopes or elements in the ENDL file from Z = 1 to Z = 29. The incident neutron energies range from 1.882 x 10-5 to 20. MeV for the composite materials and from 1.30 x 10-9 to 20. MeV for the isotopes and elements
Johnson, Kenneth L.; White, K. Preston, Jr.
2012-01-01
The NASA Engineering and Safety Center was requested to improve on the Best Practices document produced for the NESC assessment, Verification of Probabilistic Requirements for the Constellation Program, by giving a recommended procedure for using acceptance sampling by variables techniques as an alternative to the potentially resource-intensive acceptance sampling by attributes method given in the document. In this paper, the results of empirical tests intended to assess the accuracy of acceptance sampling plan calculators implemented for six variable distributions are presented.
Energy Technology Data Exchange (ETDEWEB)
Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R
1982-09-01
Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.
Calculation of Void Volume Fraction in the Subcooled and Quality Boiling Regions
International Nuclear Information System (INIS)
The complex problem of void calculation in the different regions of flow boiling is divided in two parts. The first part includes only the description of the mechanisms and the calculation of the rates of heat transfer for vapour and liquid. It is assumed that heat is removed by vapour generation, heating of the liquid that replaces the detached bubbles, and in some parts, by single phase heat transfer. By considering the rate of vapour condensation in liquid, an equation for the differential changes in the true steam quality throughout the boiling regions is obtained. Integration of this equation yields the vapour weight fraction at any position. The second part of the problem concerns the determination of the void fractions corresponding to the calculated steam qualities. For this purpose we use the derivations of Zuber and Findlay. This model is compared with data from different geometries including small rectangular channels and large rod bundles. The data covered pressures from 19 to 138 bars, heat fluxes from 18 to 120 W/cm2 with many different subcoolings and mass velocities. The agreement is generally very good
Owen, Albert K.
1987-01-01
A computer code was written which utilizes ray tracing techniques to predict the changes in position and geometry of a laser Doppler velocimeter probe volume resulting from refraction effects. The code predicts the position change, changes in beam crossing angle, and the amount of uncrossing that occur when the beams traverse a region with a changed index of refraction, such as a glass window. The code calculates the changes for flat plate, cylinder, general axisymmetric and general surface windows and is currently operational on a VAX 8600 computer system.
Jing, Wei
2014-04-01
The measurement of the two-color line of sight soot and KL factor for NO.2 diesel and jet-A fuels was conducted in an optical constant volume combustion chamber by using a high speed camera under 1000 K ambient temperature and varied oxygen concentration conditions. The ambient conditions were set as follows: four oxygen cases including 10%, 15%, 18% and 21% at 1000 K ambient temperature. KL factor and soot temperature were determined based on the two-color pyrometry technique using two band-pass filters with wavelengths of 650 nm and 550 nm. The results show that low soot temperature is observed in the upstream inner flame along the centerline, which is surrounded by high soot temperature regions, and a high KL factor is found in the same region with a low soot temperature. The results under different times suggest that soot temperature is higher for high O2 conditions during the entire flame development; meanwhile, both integrated KL factor and soot area decrease with the increase of O2 concentration. The two fuels share a similar trend of soot temperature and KL factor, however, diesel flame has a higher soot temperature and a larger high soot temperature area compared to jet-A flame. On the other hand, diesel flame shows a lower soot level during the quasi-steady state with a higher total soot level at the end of the combustion under low O2 conditions. A lower O2 concentration range from 10% to 15% is expected to have the possibility to achieve a simultaneous reduction of soot and NOx in sooting flames under the 1000 K ambient temperature condition. Copyright © 2014 SAE International.
Weather data for simplified energy calculation methods. Volume II. Middle United States: TRY data
Energy Technology Data Exchange (ETDEWEB)
Olsen, A.R.; Moreno, S.; Deringer, J.; Watson, C.R.
1984-08-01
The objective of this report is to provide a source of weather data for direct use with a number of simplified energy calculation methods available today. Complete weather data for a number of cities in the United States are provided for use in the following methods: degree hour, modified degree hour, bin, modified bin, and variable degree day. This report contains sets of weather data for 22 cities in the continental United States using Test Reference Year (TRY) source weather data. The weather data at each city has been summarized in a number of ways to provide differing levels of detail necessary for alternative simplified energy calculation methods. Weather variables summarized include dry bulb and wet bulb temperature, percent relative humidity, humidity ratio, wind speed, percent possible sunshine, percent diffuse solar radiation, total solar radiation on horizontal and vertical surfaces, and solar heat gain through standard DSA glass. Monthly and annual summaries, in some cases by time of day, are available. These summaries are produced in a series of nine computer generated tables.
Energy Technology Data Exchange (ETDEWEB)
Lewis, M.W.; Kashiwa, B.A.; Meier, R.W. [Los Alamos National Lab., NM (United States); Bishop, S. [US Army Night Vision and Electronic Sensors Directorate, Fort Belvoir, VA (United States)
1994-08-01
Two- and three-dimensional fluid-structure interaction computer programs for the simulation of nonlinear dynamics were developed and applied to a number of problems. The programs were created by coupling Arbitrary Lagrangian-Eulerian finite volume fluid dynamics programs with strictly Lagrangian finite element structural dynamics programs. The resulting coupled programs can use either fully explicit or implicit time integration. The implicit time integration is accomplished by iterations of the fluid dynamics pressure solver and the structural dynamics system solver. The coupled programs have been used to solve problems involving incompressible fluids, membrane and shell elements, compressible multiphase flows, explosions in both air and water, and large displacements. In this paper, we present the approach used for the coupling and describe test problems that verify the two-dimensional programs against an experiment and an analytical linear problem. The experiment involves an explosion underwater near an instrumented thin steel plate. The analytical linear problem is the vibration of an infinite cylinder surrounded by an incompressible fluid to a given radius.
International Nuclear Information System (INIS)
A new concept called 1 cm dose equivalent rate constant with shielding effect is introduced for estimation of radiation dose. This new concept represents an expansion of the former standard 1 cm dose equivalent rate constant (defined as μSv·m2·MBq-1·h-1) adjusted attenuation for any given thickness of shielding material (iron, lead and concrete). The 1 cm dose equivalent rate constant with shielding effect for various shielding conditions can be rapidly computed with a free-software application, KINGS-B621, which may be easily downloaded from the internet. The computed rate constants can be put out as text files which are compatible with commercially available spread-sheet software, so it is easy for users to apply the data to creation of documents concerning radiation dose. (author)
Papp, P.; Matejčík, Š.; Mach, P.; Urban, J.; Paidarová, I.; Horáček, J.
2013-06-01
The method of analytic continuation in the coupling constant (ACCC) in combination with use of the statistical Padé approximation is applied to the determination of resonance energy and width of some amino acids and formic acid dimer. Standard quantum chemistry codes provide accurate data which can be used for analytic continuation in the coupling constant to obtain the resonance energy and width of organic molecules with a good accuracy. The obtained results are compared with the existing experimental ones.
Directory of Open Access Journals (Sweden)
Beeckman H
2011-08-01
Full Text Available Wood specific gravity (WSG is an important biometric variable for aboveground biomass calculations in tropical forests. Sampling a sufficient number of trees in remote tropical forests to represent the species and size distribution of a forest to generate information on WSG can be logistically challenging. Several thousands of wood samples exist in xylaria around the world that are easily accessible to researchers. We propose the use of wood samples held in xylaria as a valid and overlooked option. Due to the nature of xylarium samples, determining wood volume to calculate WSG presents several challenges. A description and assessment is provided of five different methods to measure wood sample volume: two solid displacement methods and three liquid displacement methods (hydrostatic methods. Two methods were specifically developed for this paper: the use of laboratory parafilm to wrap the wood samples for the hydrostatic method and two glass microbeads devices for the solid displacement method. We find that the hydrostatic method with samples not wrapped in laboratory parafilm is the most accurate and preferred method. The two methods developed for this study give close agreement with the preferred method (r 2 > 0.95. We show that volume can be estimated accurately for xylarium samples with the proposed methods. Additionally, the WSG for 53 species was measured using the preferred method. Significant differences exist between the WSG means of the measured species and the WSG means in an existing density database. Finally, for 4 genera in our dataset, the genus-level WSG average is representative of the species-level WSG average.
Volume 1: Calculating potential to emit releases and doses for FEMP's and NOCs
International Nuclear Information System (INIS)
The purpose of this document is to provide Hanford Site facilities a handbook for estimating potential emissions and the subsequent offsite doses. General guidelines and information are provided to assist personnel in estimating emissions for use with U.S. Department of Energy (DOE) facility effluent monitoring plans (FEMPs) and regulatory notices of construction (NOCs), per 40 Code of Federal Regulations (CFR) Part 61, Subpart H, and Washington Administrative Code (WAC) Chapter 246-247 requirements. This document replaces Unit Dose Calculation Methods and Summary of Facility Effluent Monitoring Plan Determinations (WHC-EP-0498). Meteorological data from 1983 through 1996, 13-year data set, was used to develop the unit dose factors provided by this document, with the exception of two meteorological stations. Meteorological stations 23 and 24, located at Gable Mountain and the 100-F Area, only have data from 1986 through 1996, 10-year data set. The scope of this document includes the following: Estimating emissions and resulting effective dose equivalents (EDE) to a facility's nearest offsite receptor (NOR) for use with NOCs under 40 CFR Part 61, Subpart H, requirements Estimating emissions and resulting EDEs to a facility's or emission unit's NOR for use with NOCs under the WAC Chapter 246-247 requirements Estimating emissions and resulting EDEs to a facility's or emission unit's NOR for use with FEMPs and FEMP determinations under DOE Orders 5400.1 and 5400.5 requirements
Vidot, Kévin; Achir, Nawel; Mertz, Christian; Sinela, André; Rawat, Nadirah; Prades, Alexia; Dangles, Olivier; Fulcrand, Hélène; Dornier, Manuel
2016-05-25
Delphinidin-3-O-sambubioside and cyanidin-3-O-sambubioside are the main anthocyanins of Hibiscus sabdariffa calyces, traditionally used to make a bright red beverage by decoction in water. At natural pH, these anthocyanins are mainly in their flavylium form (red) in equilibrium with the quinonoid base (purple) and the hemiketal (colorless). For the first time, their acidity and hydration equilibrium constants were obtained from a pH-jump method followed by UV-vis spectroscopy as a function of temperature from 4 to 37 °C. Equilibrium constant determination was also performed by multivariate curve resolution (MCR). Acidity and hydration constants of cyanidin-3-O-sambubioside at 25 °C were 4.12 × 10(-5) and 7.74 × 10(-4), respectively, and were significantly higher for delphinidin-3-O-sambubioside (4.95 × 10(-5) and 1.21 × 10(-3), respectively). MCR enabled the obtaining of concentration and spectrum of each form but led to overestimated values for the equilibrium constants. However, both methods showed that formations of the quinonoid base and hemiketal were endothermic reactions. Equilibrium constants of anthocyanins in the hibiscus extract showed comparable values as for the isolated anthocyanins. PMID:27124576
International Nuclear Information System (INIS)
Highlights: • Improved soot model reproduced soot formation/oxidation at various O2 concentrations. • C2H2, precursor and soot mass increased with decreasing O2 but decreased at 12% O2. • The total area of soot reaction zone shrank remarkably at 12% oxygen. • Higher soot was from stronger formation at 18% O2 but from weaker oxidation at 15%. • The suppressed soot inception at lower O2 led to the retarded and reduced soot mass. - Abstract: The study on effects of exhaust gas recirculation (EGR) on soot behavior is very important to reduce soot emissions and control the low temperature combustion process in diesel engines. In this work, high time-resolved quantitative soot measurements were experimented on a constant volume chamber by using European low-sulfur diesel fuel at three ambient oxygen concentrations (21%, 18%, 15%). Meanwhile, an improved semi-empirical soot model was coupled into computational fluid dynamics (KIVA-3V Release 2) code for in-depth understanding the soot formation and oxidation processes. Results demonstrated that numerical results of the improved semi-empirical soot model showed good agreement with experimental data in the whole processes of soot formation/oxidation and soot distribution under different oxygen concentrations. The mass concentration of acetylene, soot precursor species and soot mass initially increased with decreasing ambient oxygen concentrations from 21% to 15% and then began to decrease at 12% oxygen, while OH radicals reduced monotonically from 21% oxygen to 12%. At 12% oxygen, the concentrations of local rich sooty zone, acetylene and soot precursor species were as high as those under higher oxygen concentrations, but the total area of soot zone shrank remarkably at 12% oxygen. Compared to 21% ambient oxygen concentration, both soot formation and oxidation rates were increased under 18% oxygen, while the higher soot mass under 18% oxygen was the result of stronger soot formation mechanism. At 15% oxygen, both
Barrow, J D
2005-01-01
We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying-alpha cosmologies is outlined in the light of all the observational constraints.
Microscopic group constants determination
International Nuclear Information System (INIS)
The method of microscopic group constants determination for nuclear reactor calculations is described in this paper. The principle of this method is group averaging of microscopic cross sections with respect to the standard spectrum. The group cross sections obtained are used for the calculation of fast critical assembly Jezebel. (author)
International Nuclear Information System (INIS)
The Experimental Cross-Section Information Library (ECSIL) as of September 1, 1976 is presented with its associated formats, conventions, and supporting programs. This volume also includes forms (i.e., plots, indexes, and listings) and the order in which data and bibliographic information may be obtained
International Nuclear Information System (INIS)
Two methods of quantitating cerebral blood flow (CBF) with iodine-123-labeled N-isopropyl-p-iodoamphetamine (I-123 IMP) and a two-compartment model had been proposed; one is the table look-up (TLU) method and the other is the autoradiographic (ARG) method. The TLU method provides values of the cerebral blood flow (CBF) values and distribution volume of I-123 IMP (Vd) independently. In the ARG method, a fixed Vd is applied for the entire brain to calculate CBF. Our purpose was to evaluate regional differences in Vd in the human brain, or possible effects of regional differences in Vd on CBF calculated by the ARG method. In the present study, two SPECT scans were acquired from each of eight normal subjects (aged 44.0±16.7) at 40 min and 180 min of mid-scan-time after intravenous 1 min infusion of 111 MBq IMP. A single arterial blood sampling was performed 10 min after the IMP infusion. All images were anatomically normalized and analyzed with SPM99 and Matlab. We generated CBF and Vd images for each subject by the TLU method and evaluated differences in Vd among brain structures. We subsequently generated another set of CBF images by the ARG method and examined differences between CBF calculated by the TLU method and that by the ARG method. Significant main effects of subject and brain structure in Vd were observed (two-way ANOVA). Vd values were higher in the deep gray matter than in the cerebral cortical regions. Among the cerebral cortical regions, no significant difference in Vd was observed. In spite of the significant differences in Vd among the brain structures, the voxel-by-voxel analyses as well as the ROI analyses revealed no statistically significant difference between CBF calculated by the TLU method and that by the ARG method. Although regional differences in Vd were observed, the present results support the assumption that a fixed Vd does not cause significant error in the calculation of CBF by the ARG method. (author)
International Nuclear Information System (INIS)
Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.
International Nuclear Information System (INIS)
A new, completely rewritten version of the FEDGROUP program system is presented in this report. The formulae and the algorithm underlying the calculation are revised. The FEDGROUP-3 is able to calculate group averaged infinite diluted and screened cross-sections, elastic and inelastic transfer matrices, point-wise cross-section sets from evaluated data in ENDF/B, KEDAK and UKNDL format. The program system is written mainly in FORTRAN-IV of IBM-OS but it can be adapted relatively easily to other type of computers. (author)
International Nuclear Information System (INIS)
Lanthanide shifting reagent (LSR) on the basis of β-diketone of asymmetric structure, containing heteroatom-oxygen in fluorinated radical, has been synthesized. Adduct formation of LSR synthesized with 4-picoline has been studied by the method of NMR spectroscopy. The composition of the adduct formed, being 1:2, is determined. Stability constant of the adduct considered is calculated by previously suggested method, which consists in taking into account of equilibrium concentrations of the substrate in two experiments. Possibilities of computer graphics for the evaluation of paramters of the mathematical model suggested are demonstrated. The values of stability stepped constants of the adduct are calculated: lg K1=3.4±0.1; lg K2=2.0±0.1
Loginov, A. V.
2015-03-01
The probabilities of the electric-dipole transitions 3 d 94 p, 3 d 94 f-3 d 10, 3 d 94 s, and 3 d 94 d in the spectra of nickel-like ions Kr IX, Sr XI, Y XII, Ru XVII, Pd XIX, and Ag XX are calculated semiempirically with the use of published energy levels.
International Nuclear Information System (INIS)
This paper is a part of documentation for the MCU-3 computer code intended to perform high precision reactor calculations with the Mote Carlo method. A description of the neutron data libraries used by the MCU-3 code is presented. The codes which provide for applying the libraries are also described, as well as the codes intended for updating the libraries
International Nuclear Information System (INIS)
Accurate quantum total reaction probabilities for the collinear reaction X + F2 (upsilon = 0.1) → XF + F (X = Mu, H, D, T) have been used to calculate collinear rate constants and activation energies. Comparison is made with collinear quasi-classical trajectory calculations and transition state theory assuming classical motion along a separable reaction coordinate and vibrational adiabaticity. Considerable differences between the quantum and quasi-classical and transition state theory results are found only for the Mu reaction at low temperatures. 5 figures, 35 references, 6 tables
Sparavigna, Amelia Carolina
2012-01-01
As proposed in a previous paper, the decorations of ancient objects can provide some information on the approximate evaluations of constant {\\pi}, the ratio of circumference to diameter. Here we discuss some disks found in the tomb of Hemaka, the chancellor of a king of the First Dynasty of Egypt, about 3000 BC. The discussion is based on measurements of the dimensionless ratio of lengths.
Energy Technology Data Exchange (ETDEWEB)
Robinson, H.P.; Potter, Elinor
1971-03-01
This collection of mathematical data consists of two tables of decimal constants arranged according to size rather than function, a third table of integers from 1 to 1000, giving some of their properties, and a fourth table listing some infinite series arranged according to increasing size of the coefficients of the terms. The decimal values of Tables I and II are given to 20 D.
Energy Technology Data Exchange (ETDEWEB)
Ilakovac, A.; Tadic-acute-accent, D.D.; Coutinho, F.A.B.; Krmpotic-acute-accent, F.
1986-04-15
We study the introduction of the internal dynamical variables for consituent quarks. These variables are related to the center-of-mass of a nucleon. The problem is connected with the description of spinorial properties of the quarks. The spinors must be artificially introduced in a harmonic oscillator (HO) model. Experimental values of the magnetic moment and the axial-vector coupling constant of a nucleon can be easily reproduced. The theoretical results are not sensitive to the theoretical details; they follow from the general properties of the quark structure of baryons. The connections with the relativistic HO models are also discussed. The case of a very small confinement radius is explored in the Appendix.
International Nuclear Information System (INIS)
We study the introduction of the internal dynamical variables for consituent quarks. These variables are related to the center-of-mass of a nucleon. The problem is connected with the description of spinorial properties of the quarks. The spinors must be artificially introduced in a harmonic oscillator (HO) model. Experimental values of the magnetic moment and the axial-vector coupling constant of a nucleon can be easily reproduced. The theoretical results are not sensitive to the theoretical details; they follow from the general properties of the quark structure of baryons. The connections with the relativistic HO models are also discussed. The case of a very small confinement radius is explored in the Appendix
Indian Academy of Sciences (India)
Samira Shoeibi Mohsenabadi; Mohammad Ebrahim Zomorrodian
2013-11-01
The next-to-next-to-leading order (NNLO) quantum chromodynamics (QCD) correction to the first three moments of the four event-shape variables in electron–positron annihilation, the thrust, heavy jet mass, wide, and total jet broadening, is computed. It is observed that the NNLO correction gives a better agreement between the theory and the experimental data. Also, by using the above observables, the strong coupling constant () is determined and how much its value is affected by the NNLO correction is demonstrated. By combining the results for all variables at different centre-of-mass energies $(M_{Z^{°}})$ = 0.1248 ± 0.0009 $({\\text{exp.}})_{-0.0144}^{+0.0283} ({\\text{theo.}})$ is obtained.
Walter Borzani
2008-01-01
The volume of biomass in the fermenting medium may significantly affect the values of fermentation parameters calculated from the measured concentrations of the substrates and/or products. The corrections proposed in this paper should be evaluated and, depending on their magnitude, considered in order to obtain more representative results. A numerical example is presented.O volume da biomassa no meio em fermentação pode afetar significativamente os parâmetros do processo calculados a partir d...
Energy Technology Data Exchange (ETDEWEB)
Koponen, B.L.; Hampel, V.E.
1982-10-21
This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains-in chronological order-the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41.
Institute of Scientific and Technical Information of China (English)
王渊旭; 王春雷
2003-01-01
Electronic structure of ferroelectric PbTiO3 and BaTiO3 is calculated by the full potential linearized augmented plane wave method. The total energy as a function of the displacement of Ti-cation is obtained for PbTiO3 and BaTiO3 at different cell volumes. At experimental cell volume, Ti-displacement lowers the total energy and the ferroelectricity is stable. When the cell volume is reduced to 90%, total energy is increased with Ti-displacement and ferroelectricity will disappear. The cell volume effect is also confirmed by comparison of the density of states of Ti and O at different cell volumes.
International Nuclear Information System (INIS)
This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains-in chronological order-the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41
Directory of Open Access Journals (Sweden)
Etienne Garin
2011-01-01
Full Text Available Objectives. The aim of this study was to assess the effectiveness of SPECT/CT for volume measurements and to report a case illustrating the major impact of SPECT/CT in calculating the vascularized liver volume and dosimetry prior to injecting radiolabelled yttrium-90 microspheres (Therasphere. Materials and Methods. This was a phantom study, involving volume measurements carried out by two operators using SPECT and SPECT/CT images. The percentage of error for each method was calculated, and interobserver reproducibility was evaluated. A treatment using Therasphere was planned in a patient with three hepatic arteries, and the quantitative analysis of SPECT/CT for this patient is provided. Results. SPECT/CT volume measurements proved to be accurate (mean error <6% for volumes ≥16 cm3 and reproductive (interobserver agreement = 0.9. In the case report, 99mTc-MAA SPECT/CT identified a large liver volume, not previously identified with angiography, which was shown to be vascularized after selective MAA injection into an arterial branch, resulting in a large modification in the activity of Therasphere used. Conclusions. MAA SPECT/CT is accurate for vascularized liver volume measurements, providing a valuable contribution to the therapeutic planning of patients with complex hepatic vascularization.
International Nuclear Information System (INIS)
In this paper a new method using the combination of Neural Networks and the Newton-Raphson algorithm is developped. The technique consists of the use of the solution obtained by Newton-Raphson algorithm between 0.5 and 2.1eV for pure manganese (Mn) and for the amorphous metallic alloy Al88Mn12, to construct two parts of datasets; the first one is used for training the neural network and the second one for the validation tests. The validated neural network model is applied to the determination of optical constants of the two materials Mn and Al88Mn12 in the range of 0.5 and 6.2eV (IR-VIS-UV). The results obtained over all the studied energy range are used to trace back to dielectric function, optical absorption and electronic structure of the same material. By using the partial solution obtained by Newton-Raphson as a database of the neural network prediction model, it is shown that the obtained results are in accordance with those of the literature which consolidate the efficiency of the suggested approach.
Rayne, Sierra; Forest, Kaya
2016-05-11
The SPARC software program was used to estimate the acid-catalyzed, neutral, and base-catalyzed hydrolysis rate constants for the polymeric brominated flame retardants BC-58 and FR-1025. Relatively rapid hydrolysis of BC-58, producing 2,4,6-tribromophenol-and ultimately tetrabromobisphenol A-as the hydrolytically stable end products from all potential hydrolysis reactions, is expected in both environmental and biological systems with starting material hydrolytic half-lives (t1/2,hydr) ranging from less than 1 h in marine systems, several hours in cellular environments, and up to several weeks in slightly acid fresh waters. Hydrolysis of FR-1025 to give 2,3,4,5,6-pentabromobenzyl alcohol is expected to be slower (t1/2,hydr less than 0.5 years in marine systems up to several years in fresh waters) than BC-58, but is also expected to occur at rates that will contribute significantly to environmental and in vivo loadings of this compound. PMID:26889790
International Nuclear Information System (INIS)
A surprisingly simple relationship for particle and quark masses is given as m = x*y*me. Thereby y = 1 and x = 1/α, β and β/α for a hypothetic mass m0, the nucleon and the Higgs boson. With y = 4/3 instead y = 1 one obtains the masses of the strange-, charm-, and top quark, with x = β/α and y = 2/π the Z boson and with the π-2 fold thereof the W boson. The aforementioned m0 is the building block for calculating, as integer multiples, all other meson- and baryon masses with better than 2 % accuracy.
International Nuclear Information System (INIS)
The aim of this study was to measure the volume of each pulmonary segment by volumetric computed tomography (CT) data using a newly developed three-dimensional software application and to identify the differences between those with chronic obstructive pulmonary disease (COPD) and controls. CT scans of 11 COPD patients and 16 controls were included. The volume of each pulmonary segment was measured by each of two operators to evaluate the reproducibility of the software. This measured volume was then divided by the total lung volume to revise individual variations. Volumes of the right (rt) S2, rt S5, left (lt) S1+S2, lt S3, and lt S5 were significantly larger in COPD patients than in controls (P<0.05). Regarding the ratio of the volume of each pulmonary segment per total lung volume, the areas of rt S2 and lt S1+S2 were significantly larger in COPD patients than in controls (P<0.05), whereas lt S10 was significantly smaller in COPD patients than in controls (P<0.05). We measured the volume of each pulmonary segment based on volumetric CT data using this software. In addition, we demonstrated that the upper lung volume of COPD subjects was larger than that of controls, whereas the lower lung volumes were almost the same. (author)
A first-principles approach to finite temperature elastic constants
Energy Technology Data Exchange (ETDEWEB)
Wang, Y; Wang, J J; Zhang, H; Manga, V R; Shang, S L; Chen, L-Q; Liu, Z-K [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)
2010-06-09
A first-principles approach to calculating the elastic stiffness coefficients at finite temperatures was proposed. It is based on the assumption that the temperature dependence of elastic stiffness coefficients mainly results from volume change as a function of temperature; it combines the first-principles calculations of elastic constants at 0 K and the first-principles phonon theory of thermal expansion. Its applications to elastic constants of Al, Cu, Ni, Mo, Ta, NiAl, and Ni{sub 3}Al from 0 K up to their respective melting points show excellent agreement between the predicted values and existing experimental measurements.
Formulas for determining rotational constants
Guelachvili, G.
This document is part of Subvolume B `Linear Triatomic Molecules', Part 9, of Volume 20 `Molecular Constants mostly from Infrared Spectroscopy' of Landolt-Börnstein Group II `Molecules and Radicals'. Part of the introduction, it states formulas for determining rotational constants, band center, band origin, and quadrupole coupling. Specific comments relate to BHO (HBO) and COS (OCS).
Negahdar, M J; Kadbi, Mo; Cha, J; Cebral, J; Amini, A
2013-01-01
Use of phase-contrast (PC) MRI in assessment of hemodynamics has significant clinical importance. In this paper we develop a novel approach to determination of hemodynamic pressures. 3D gradients of pressure obtained from Navier-Stokes equation are expanded into a series of orthogonal basis functions, and are subsequently projected onto an integrable subspace. Before the projection step however, a scheme is devised to eliminate the discontinuity at the vessel and image boundaries. In terms of the computation time, the proposed approach significantly improves on previous iterative methods for pressure calculations. The method has been validated using computational fluid dynamic simulations and in-vitro MRI studies of stenotic flows. PMID:24110706
球积术案例及其分析%Cases and analysis of calculating the volume of the sphere
Institute of Scientific and Technical Information of China (English)
曲安京; 冯振举; 赵继伟
2011-01-01
目的 以数学史上的4种球积术为例,说明数学史在中学数学教学中应用的意义.方法 案例研究和比较分析.结果 4种历史上的球积术方法体现出两种数学传统下数学家对相同问题的不同处理,对其在数学课堂的适当应用既可以更好地增进学生对具体知识的理解,也可以提高学生的数学修养.结论 开发数学史的教学案例,并将其有效地应用于数学教学中,对于数学教育目标的实现具有重要帮助.%Aim To illustrate the effect and significance of the application of the history of mathematics to mathematical class of middle schools. Methods Case study and comparative analysis. Results The 4 historical methods of calculating the volume of the sphere indicate mathematician's different treatment to a same problem under two different mathematical traditions. The proper application of these methods to mathematical class will not only strengthen students' understanding of concrete knowledge, but also improve their mathematical accomplishment.Conclusion It will be greatly helpful for realizing the target of mathematical education that HPM cases are constructed and applied effectively to mathematical class.
International Nuclear Information System (INIS)
Volume property is the necessary thermodynamic property in the design and operation of the CO2 capture and storage system (CCS). Because of their simple structures, cubic equations of state (EOS) are preferable to be applied in predicting volumes for engineering applications. This paper evaluates the reliabilities of seven cubic EOS, including PR, PT, RK, SRK, MPR, MSRK and ISRK for predicting volumes of binary CO2 mixtures containing CH4, H2S, SO2, Ar and N2, based on the comparisons with the collected experimental data. Results show that for calculations on the volume properties of binary CO2 mixtures, PR and PT are generally superior to others for all of the studied mixtures. In addition, it was found that the binary interaction parameter has clear effects on the calculating accuracy of an EOS in the volume calculations of CO2 mixtures. In order to improve the accuracy, kij was calibrated for all of the EOS regarding the gas and liquid phases of all the studied binary CO2 mixtures, respectively.
Tekin-Sitrava, Reyhan; Isiksal-Bostan, Mine
2014-01-01
This qualitative study examined middle school students' performance, solution strategies, difficulties and the underlying reasons for their difficulties in calculating the volume of a rectangular prism. The data was collected from 35 middle school students (6th, 7th and 8th grade students) enrolled in a private school in Istanbul, Turkey. The…
Energy Technology Data Exchange (ETDEWEB)
Frericks, Bernd B.J. [Hanover Medical School, Departments of Radiology and Surgery, Hannover (Germany); University of Berlin, Department of Radiology, Berlin (Germany); Charite - University Medicine Berlin, Department of Radiology and Nuclear Medicine, Berlin (Germany); Kirchhoff, Timm D.; Shin, Hoen-Oh; Stamm, Georg; Merkesdal, Sonja; Abe, Takehiko; Galanski, Michael [Hanover Medical School, Departments of Radiology and Surgery, Hannover (Germany); Hanover Medical School, Department of Diagnostic Radiology, Hannover (Germany); Schenk, Andrea; Peitgen, Heinz-Otto [Hanover Medical School, Departments of Radiology and Surgery, Hannover (Germany); MeVis - Center for Medical Diagnostic Systems and Visualization, Bremen (Germany); Klempnauer, Juergen [Hanover Medical School, Departments of Radiology and Surgery, Hannover (Germany); Hanover Medical School, Department of Visceral- and Transplantation Surgery, Hannover (Germany); Nashan, Bjoern [Hanover Medical School, Departments of Radiology and Surgery, Hannover (Germany); Hanover Medical School, Department of Visceral- and Transplantation Surgery, Hannover (Germany); Dalhousie University, Multi Organ Transplant Program, Halifax, Nova Scotia (Canada)
2006-12-15
The purpose was to assess the volumes of the different hepatic territories and especially the drainage of the right paramedian sector in adult living donor liver transplantation (ALDLT). CT was performed in 40 potential donors of whom 28 underwent partial living donation. Data sets of all potential donors were postprocessed using dedicated software for segmentation, volumetric analysis and visualization of liver territories. During an initial period, volumes and shapes of liver parts were calculated based on the individual portal venous perfusion areas. After partial hepatic congestion occurring in three grafts, drainage territories with special regard to MHV tributaries from the right paramedian sector, and the IRHV were calculated additionally. Results were visualized three-dimensionally and compared to the intraoperative findings. Calculated graft volumes based on hepatic venous drainage and graft weights correlated significantly (r=0.86,P<0.001). Mean virtual graft volume was 930 ml and drained as follows: RHV: 680 ml, IRHV: 170 ml (n=11); segment 5 MHV tributaries: 100 ml (n=16); segment 8 MHV tributaries: 110 ml (n=20). When present, the mean aberrant venous drainage fraction of the right liver lobe was 28%. The evaluated protocol allowed a reliable calculation of the hepatic venous draining areas and led to a change in the hepatic venous reconstruction strategy at our institution. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hussain, Raihan [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)], E-mail: raihan_h@yahoo.com; Kudo, Takashi [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)], E-mail: tkudo@u-fukui.ac.jp; Tsujikawa, Testuya; Kobayashi, Masato; Fujibayashi, Yasuhisa; Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)
2009-11-15
Introduction: The purpose of this study was to validate the calculation of myocardial oxidative metabolism rate using a parametric clearance rate constant (k{sub mono}) image. Methods: Fifteen subjects (seven volunteers, eight patients) were studied. Dynamic PET was acquired after intravenous injection of 700 MBq of [{sup 11}C]acetate. The clearance rate constant of [{sup 11}C]acetate (k{sub mono}) was calculated pixel by pixel to generate the parametric k{sub mono} image. The k{sub mono} values from this image and those calculated from the dynamic image were compared in the same regions of interest (ROIs). Results: Two different methods showed an excellent correlation except in the very low range. Regression equations were y=0.99x+0.0034 (r{sup 2}=0.86, P<.001) and y=1.16x-0.0077 (r{sup 2}=0.87, P<.001) in normal volunteer and patient groups, respectively, and y=1.07x-0.0019 (r{sup 2}=0.87, P<.001) when combined. Conclusions: Both methods exhibited similar values of k{sub mono}. Parametric k{sub mono} image may result in better visual understanding of regional myocardial oxidative metabolism.
Algorithm for structure constants
Paiva, F M
2011-01-01
In a $n$-dimensional Lie algebra, random numerical values are assigned by computer to $n(n-1)$ especially selected structure constants. An algorithm is then created, which calculates without ambiguity the remaining constants, obeying the Jacobi conditions. Differently from others, this algorithm is suitable even for poor personal computer. ------------- En $n$-dimensia algebro de Lie, hazardaj numeraj valoroj estas asignitaj per komputilo al $n(n-1)$ speciale elektitaj konstantoj de strukturo. Tiam algoritmo estas kreita, kalkulante senambigue la ceterajn konstantojn, obeante kondicxojn de Jacobi. Malsimile al aliaj algoritmoj, tiu cxi tauxgas ecx por malpotenca komputilo.
Directory of Open Access Journals (Sweden)
Inseon Ryoo
Full Text Available PURPOSE: To evaluate the usefulness of dynamic susceptibility contrast (DSC enhanced perfusion MR imaging in predicting major genetic alterations in glioblastomas. MATERIALS AND METHODS: Twenty-five patients (M:F = 13∶12, mean age: 52.1±15.2 years with pathologically proven glioblastoma who underwent DSC MR imaging before surgery were included. On DSC MR imaging, the normalized relative tumor blood volume (nTBV of the enhancing solid portion of each tumor was calculated by using dedicated software (Nordic TumorEX, NordicNeuroLab, Bergen, Norway that enabled semi-automatic segmentation for each tumor. Five major glioblastoma genetic alterations (epidermal growth factor receptor (EGFR, phosphatase and tensin homologue (PTEN, Ki-67, O6-methylguanine-DNA methyltransferase (MGMT and p53 were confirmed by immunohistochemistry and analyzed for correlation with the nTBV of each tumor. Statistical analysis was performed using the unpaired Student t test, ROC (receiver operating characteristic curve analysis and Pearson correlation analysis. RESULTS: The nTBVs of the MGMT methylation-negative group (mean 9.5±7.5 were significantly higher than those of the MGMT methylation-positive group (mean 5.4±1.8 (p = .046. In the analysis of EGFR expression-positive group, the nTBVs of the subgroup with loss of PTEN gene expression (mean: 10.3±8.1 were also significantly higher than those of the subgroup without loss of PTEN gene expression (mean: 5.6±2.3 (p = .046. Ki-67 labeling index indicated significant positive correlation with the nTBV of the tumor (p = .01. CONCLUSION: We found that glioblastomas with aggressive genetic alterations tended to have a high nTBV in the present study. Thus, we believe that DSC-enhanced perfusion MR imaging could be helpful in predicting genetic alterations that are crucial in predicting the prognosis of and selecting tailored treatment for glioblastoma patients.
Deridder, Sander; Desmet, Gert
2012-02-01
Using computational fluid dynamics (CFD), the effective B-term diffusion constant γ(eff) has been calculated for four different random sphere packings with different particle size distributions and packing geometries. Both fully porous and porous-shell sphere packings are considered. The obtained γ(eff)-values have subsequently been used to determine the value of the three-point geometrical constant (ζ₂) appearing in the 2nd-order accurate effective medium theory expression for γ(eff). It was found that, whereas the 1st-order accurate effective medium theory expression is accurate to within 5% over most part of the retention factor range, the 2nd-order accurate expression is accurate to within 1% when calculated with the best-fit ζ₂-value. Depending on the exact microscopic geometry, the best-fit ζ₂-values typically lie in the range of 0.20-0.30, holding over the entire range of intra-particle diffusion coefficients typically encountered for small molecules (0.1 ≤ D(pz)/D(m) ≤ 0.5). These values are in agreement with the ζ₂-value proposed by Thovert et al. for the random packing they considered. PMID:22236565
Institute of Scientific and Technical Information of China (English)
朱丽; 杨旭武; 陈三平; 高胜利; 史启祯
2004-01-01
Four ternary solid complexes were synthesized with sodium diethyldithiocarbamate (NaEt2dtc) (b), 1,10-phenanthroline (o-phen) (c) and hydrated lanthanide chlorides in absolute ethanol by an improved reported method. The complexes were identified as the general formula of RE(Et2dtc)3(phen) (RE=La, Pr, Nd, Sm) by chemical and elemental analyses. IR spectra of the complexes showed that the RE3+ was coordinated with sulfur atoms of NaEt2dtc and nitrogen atoms of o-phen. The constant-volume combustion energies of complexes, △cU,were determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion,(△cH-m), and standard enthalpies of formation, (△fH-m), were calculated for these complexes, respectively.
Molecular dynamics at constant temperature and pressure
Toxvaerd, S.
1993-01-01
Algorithms for molecular dynamics (MD) at constant temperature and pressure are investigated. The ability to remain in a regular orbit in an intermittent chaotic regime is used as a criterion for long-time stability. A simple time-centered algorithm (leap frog) is found to be the most stable of the commonly used algorithms in MD. A model of N one-dimensional dimers with a double-well intermolecular potential, for which the distribution functions at constant temperature T and pressure P can be calculated, is used to investigate MD-NPT dynamics. A time-centered NPT algorithm is found to sample correctly and to be very robust with respect to volume scaling.
Adibi, Atoosa; Mortazavi, Mojgan; Shayganfar, Azin; Kamal, Sima; Azad, Roya; Aalinezhad, Marzieh
2016-01-01
It is essential to ascertain the state of health and renal function of potential kidney donors before organ removal. In this regard, one of the primary steps is to estimate the donor's glomerular filtration rate (GFR). For this purpose, the modification of diet in renal disease (MDRD) and the Cockcroft-Gault (CG) formulas has been used. However, these two formulas produce different results and finding new techniques with greater accuracy is required. Measuring the renal volume from computed tomography (CT) scan may be a valuable index to assess the renal function. This study was conducted to investigate the correlation between renal volume and the GFR values in potential living kidney donors referred to the multislice imaging center at Alzahra Hospital during 2014. The study comprised 66 subjects whose GFR was calculated using the two aforementioned formulas. Their kidney volumes were measured by using 64-slice CT angiography and the correlation between renal volume and GFR values were analyzed using the Statistical Package for the Social Science software. There was no correlation between the volume of the left and right kidneys and the MDRD-based estimates of GFR (P = 0.772, r = 0.036, P = 0.251, r = 0.143, respectively). A direct linear correlation was found between the volume of the left and right kidneys and the CG-based GFR values (P = 0.001, r = 0.397, P kidney volume derived from multislice CT scan can help predict the GFR value in kidney donors with normal renal function. The limitations of our study include the small sample size and the medium resolution of 64-slice multislice scanners. Further studies with larger sample size and using higher resolution scanners are warranted to determine the accuracy of this method in potential kidney donors. PMID:27424682
International Nuclear Information System (INIS)
Purpose: We have analyzed the dose volume histogram of 140 CT based HDR brachytherapy plans and evaluated the dose received to OAR ; rectum, bladder and sigmoid colon based on recommendations from ICRU and Image guided brachytherapy working group for cervical cancer . Methods: Our treatment protocol consist of XRT to whole pelvis with 45 Gy at 1.8Gy/fraction followed by 30 Gy at 6 Gy per fraction by HDR brachytherapy in 2 weeks . The CT compatible tandem and ovoid applicators were used and stabilized with radio opaque packing material. The patient was stabilized using special re-locatable implant table and stirrups for reproducibility of the geometry during treatment. The CT scan images were taken at 3mm slice thickness and exported to the treatment planning computer. The OAR structures, bladder, rectum and sigmoid colon were outlined on the images along with the applicators. The prescription dose was targeted to A left and A right as defined in Manchester system and optimized on geometry . The dosimetry was compared on all plans using the parameter Ci.sec.cGy-1 . Using the Dose Volume Histogram (DVH) obtained from the plans the doses to rectum, sigmoid colon and bladder for ICRU defined points and 2cc volume were analyzed and reported. The following criteria were used for limiting the tolerance dose by volume (D2cc) were calculated. The rectum and sigmoid colon doses were limited to <75Gy. The bladder dose was limited to < 90Gy from both XRT and HDR brachytherapy. Results: The average total (XRT+HDRBT) BED values to prescription volume was 120 Gy. Dose 2cc to rectum was 70Gy +/− 17Gy, dose to 2cc bladder was 82+/−32 Gy. The average Ci.sec.cGy-1 calculated for the HDR plans was 6.99 +/− 0.5 Conclusion: The image based treatment planning enabled to evaluati volume based dose to critical structures for clinical interpretation
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Nair, M; Li, C; White, M; Davis, J [Joe Arrington Cancer Center, Lubbock, TX (United States)
2014-06-15
Purpose: We have analyzed the dose volume histogram of 140 CT based HDR brachytherapy plans and evaluated the dose received to OAR ; rectum, bladder and sigmoid colon based on recommendations from ICRU and Image guided brachytherapy working group for cervical cancer . Methods: Our treatment protocol consist of XRT to whole pelvis with 45 Gy at 1.8Gy/fraction followed by 30 Gy at 6 Gy per fraction by HDR brachytherapy in 2 weeks . The CT compatible tandem and ovoid applicators were used and stabilized with radio opaque packing material. The patient was stabilized using special re-locatable implant table and stirrups for reproducibility of the geometry during treatment. The CT scan images were taken at 3mm slice thickness and exported to the treatment planning computer. The OAR structures, bladder, rectum and sigmoid colon were outlined on the images along with the applicators. The prescription dose was targeted to A left and A right as defined in Manchester system and optimized on geometry . The dosimetry was compared on all plans using the parameter Ci.sec.cGy-1 . Using the Dose Volume Histogram (DVH) obtained from the plans the doses to rectum, sigmoid colon and bladder for ICRU defined points and 2cc volume were analyzed and reported. The following criteria were used for limiting the tolerance dose by volume (D2cc) were calculated. The rectum and sigmoid colon doses were limited to <75Gy. The bladder dose was limited to < 90Gy from both XRT and HDR brachytherapy. Results: The average total (XRT+HDRBT) BED values to prescription volume was 120 Gy. Dose 2cc to rectum was 70Gy +/− 17Gy, dose to 2cc bladder was 82+/−32 Gy. The average Ci.sec.cGy-1 calculated for the HDR plans was 6.99 +/− 0.5 Conclusion: The image based treatment planning enabled to evaluati volume based dose to critical structures for clinical interpretation.
Brumby, Paul E; Haslam, Andrew J.; de Miguel, Enrique; Jackson, George
2010-01-01
Abstract An effcient and versatile method to calculate the components of the pressure tensor for hard-body fluids of generic shape from the perspective of molecular simulation is presented. After due consideration of all the possible repulsive contributions exerted by molecules upon their surroundings during an anisotropic system expansion, it is observed that such a volume changevcan, for non-spherical molecules, give rise to configurations where overlaps occur. This feature of an...
International Nuclear Information System (INIS)
A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme
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De Neve, W.; Derycke, S.; De Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde
1995-12-01
A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme.
International Nuclear Information System (INIS)
Multiphase flows, type oil-water-gas are very common among different industrial activities, such as chemical industries and petroleum extraction, and its measurements show some difficulties to be taken. Precisely determining the volume fraction of each one of the elements that composes a multiphase flow is very important in chemical plants and petroleum industries. This work presents a methodology able to determine volume fraction on Annular and Stratified multiphase flow system with the use of neutrons and artificial intelligence, using the principles of transmission/scattering of fast neutrons from a 241Am-Be source and measurements of point flow that are influenced by variations of volume fractions. The proposed geometries used on the mathematical model was used to obtain a data set where the thicknesses referred of each material had been changed in order to obtain volume fraction of each phase providing 119 compositions that were used in the simulation with MCNP-X -computer code based on Monte Carlo Method that simulates the radiation transport. An artificial neural network (ANN) was trained with data obtained using the MCNP-X, and used to correlate such measurements with the respective real fractions. The ANN was able to correlate the data obtained on the simulation with MCNP-X with the volume fractions of the multiphase flows (oil-water-gas), both in the pattern of annular flow as stratified, resulting in a average relative error (%) for each production set of: annular (air = 3.85; water = 4.31; oil=1.08); stratified (air = 3.10, water 2.01, oil = 1.45). The method demonstrated good efficiency in the determination of each material that composes the phases, thus demonstrating the feasibility of the technique. (author)
Meson decay constants from Nf=2 clover fermions
International Nuclear Information System (INIS)
We present recent results for meson decay constants calculated on configurations with two flavours of O(a)-improved Wilson fermions. Non-perturbative renormalisation is applied and quark mass dependencies as well as finite volume and discretisation effects are investigated. In this work we also present the first computation of the coupling of the light vector mesons to the tensor current using dynamical fermions. (orig.)
Kilburn, K H; Warshaw, R H; Thornton, J C; Thornton, K.; Miller, A
1992-01-01
BACKGROUND: Published predicted values for total lung capacity and residual volume are often based on a small number of subjects and derive from different populations from predicted spirometric values. Equations from the only two large studies gave smaller predicted values for total lung capacity than the smaller studies. A large number of subjects have been studied from a population which has already provided predicted values for spirometry and transfer factor for carbon monoxide. METHODS: T...
Institute of Scientific and Technical Information of China (English)
邓东阁; 武新军
2015-01-01
It is of great significance to research on methods for obtaining the initial magnetization curve, the important magnetic property of ferromagnetic materials. In the existing methods, a time-varying magnetic field is adopted as the excitation field. To obtain the initial magnetization curve, magnetic field and induced magnetic flux density in the specimen have to be measured step-by-step as the excitation field changes, and this is ineﬃcient. Thus, a calculation method for initial magnetization curve based on time-space transformation is proposed in this paper. In this method, an elongated rod or a circular ring is used as the specimen. A spatially varying magnetic field generated by constant magnetization is utilized as the excitation field. The strength of the excitation field changes with the spatial positions of the specimen. Under the action of the excitation field, the magnetic field strength within the specimen is calculated by means of the responding magnetic field strength on the surface of the specimen according to the continuity of the tangential magnetic field strength. While, based on the Gauss’ law for magnetism, the law of approach to saturation and the basic equation of magnetization curve in Rayleigh region, the induced magnetic flux density within the specimen can be calculated from the responding magnetic flux density on the surface of the specimen. After obtaining the magnetic field strength and magnetic flux density in the specimen, the initial magnetization curve can be obtained. To verify theoretically the correctness of the method, simulations are carried out with an elongated rod and a circular ring. In experiments, a spatially varying magnetic field generated by DC coils is applied on the specimen as the excitation field. The initial magnetization curve calculated from the magnetic field strength and magnetic flux density on the surface of the specimen is similar to the known initial magnetization curve. Experimental results also show
Lazarev, V.; Geidmanis, D.
2016-02-01
The theoretical problem solved in this article is the calculation of thermodynamic parameters such as final temperature, distribution of the liquid and dry saturated vapour phases of the substance that are considered to be in thermodynamic equilibrium, and pressure of the system of several reaction products after adding to the system a certain amount of heat or the thermal effect released during rapid exothermic reaction in a closed volume that occurs so fast that it can be considered to be adiabatic, and when the volume of liquid reagents is several orders of magnitude less than the volume of the reactor. The general multi-substance problem is reduced to a theoretical problem for one substance of calculation thermodynamic parameters of system after adding a certain amount of heat that gives theoretically rigorous isochoric calculation. In this article, we substantiate our view that isochoric pass of calculation is more robust compared to seemingly more natural isobaric pass of calculation, if the later involves quite not trivial calculation of the adiabatic compression of a two-phase system (liquid - dry saturated vapour) that can pass itself into another kind of state (liquid - wet saturated vapour), which requires, apparently, more complex descriptions compared with isochoric calculation because the specific heat capacity of wet saturated vapour can be negative. The solved theoretical problem relates to a practical problem that has been a driver for our research as part of a design of the reactor of the titanium reduction from magnesium and titanium tetrachloride supplied into atmosphere of the reactor at high temperatures when both reagents are in gaseous state. The reaction is known to be exothermic with a high thermal effect, and estimate of the final temperature and pressure of the products of reaction, for instance, designing the reactor allows eliminating the possibility of the reaction products to penetrate backwards into supply tracts of the reagents
Kerma constant of gamma radiation
International Nuclear Information System (INIS)
The values are tabulated of the gamma kerma constant for 106 radionuclides and an energy threshold of δ=0, 10, 20 and 30 keV. The calculated values will be useful in gamma radiation protection for ease of calculation of the kerma rate from a point radiation source. The study was required in view of the consistent introduction of SI units. (author)
Directory of Open Access Journals (Sweden)
Walter Borzani
2008-06-01
Full Text Available The volume of biomass in the fermenting medium may significantly affect the values of fermentation parameters calculated from the measured concentrations of the substrates and/or products. The corrections proposed in this paper should be evaluated and, depending on their magnitude, considered in order to obtain more representative results. A numerical example is presented.O volume da biomassa no meio em fermentação pode afetar significativamente os parâmetros do processo calculados a partir das medidas das concentrações de substratos e/ou produtos. Correções propostas neste trabalho deveriam ser avaliadas e, dependendo de seus valores, consideradas a fim de obter resultados mais representativos. Apresenta-se um exemplo numérico.
Viscosity calculation of polydisperse branching polymers near gel point
Sievers, D.
1980-01-01
The viscosity of randomly branched polymers has been calculated based on an interpolation formula by Marrinan and Hermans, which contains dependent on certain constants both the so called excluded-volume-effect and the free-draining limit. Closer inspection of the constants used shows that the first choice is better direct near the gel point and yields a logarithmic divergence of the viscosity or a finite limit depending on the gelation theory used. The theoretical calculated values for the i...
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-06-01
This volume of the progress report provides documentation of reactor physics and criticality safety studies conducted in the Russian Federation during fiscal year 1997 and sponsored by the Fissile Materials Disposition Program of the US Department of Energy. Descriptions of computational and experimental benchmarks for the verification and validation of computer programs for neutron physics analyses are included. All benchmarks include either plutonium, uranium, or mixed uranium and plutonium fuels. Calculated physics parameters are reported for all of the contaminated benchmarks that the United States and Russia mutually agreed in November 1996 were applicable to mixed-oxide fuel cycles for light-water reactors.
International Nuclear Information System (INIS)
This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15±9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256±80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses. (orig.)
Cosmological Constant, Fine Structure Constant and Beyond
Wei, Hao; Zou, Xiao-Bo; Li, Hong-Yu; Xue, Dong-Ze
2016-01-01
In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view...
ZEMO system for generating group constants
International Nuclear Information System (INIS)
The code system ZEMO for generating 26 group and 140-group constant sets for fast breeder reactors neutronics is considered. Group constant libraries, calculational techniques, formats of generated group constant sets and code control parameters are described. Results of one-dimensional model calculations for some critical assemblies and results of investigation of sodium void reactivity effect calculational error caused by 26-group approximation for two-dimensional model of BN-800 are presented. 14 refs.; 1 fig.; 3 tabs
Directory of Open Access Journals (Sweden)
Andreas Kaiser
2014-07-01
Full Text Available This study presents a computer vision application of the structure from motion (SfM technique in three dimensional high resolution gully monitoring in southern Morocco. Due to impractical use of terrestrial Light Detection and Ranging (LiDAR in difficult to access gully systems, the inexpensive SfM is a promising tool for analyzing and monitoring soil loss, gully head retreat and plunge pool development following heavy rain events. Objects with known dimensions were placed around the gully scenes for scaling purposes as a workaround for ground control point (GCP placement. Additionally, the free scaling with objects was compared to terrestrial laser scanner (TLS data in a field laboratory in Germany. Results of the latter showed discrepancies of 5.6% in volume difference for erosion and 1.7% for accumulation between SfM and TLS. In the Moroccan research area soil loss varied between 0.58 t in an 18.65 m2 narrowly stretched gully incision and 5.25 t for 17.45 m2 in a widely expanded headcut area following two heavy rain events. Different techniques of data preparation were applied and the advantages of SfM for soil erosion monitoring under complex surface conditions were demonstrated.
封冻期流量推求方法的探讨%Exploration for volume calculation method in the freezing period
Institute of Scientific and Technical Information of China (English)
刘国锋; 李周明; 苍学深
2001-01-01
封冻期径流成分按补给来源分主要以地下水补给为主。根据地下水退水的一般规律，提出了针对天然河道封冻期流量推求方法的建议。在一般情况下，中小河流稳定封冻期流量推求应以实测流量过程线法为主。%Based on the supplying resources,ground water was considered as the primary resource to the main runoff in the freezing period.According to the general pattern of ground water lowering,this paper suggested a volume calculation method in the natural river courses in the freezing period.The result showed that the measured volume“Course Line” method should be generally taken as the primary one in calculation of the stable volume of the medium-and small-size rivers during the freezing period.
International Nuclear Information System (INIS)
Radiation induced normal tissue complication probability is calculated for three different organs: brain, liver and kidney. The model applied is a reliability model where the volume effect of the tissue is described by the structural parameter, k, which reflects the architecture of the functional subunits of the organ. The complication probability depends on k, the inactivation probability of the functional subunits (p) and the irradiated volume fraction (n). For partial, homogeneous irradiation of the brain, a k-value close to unity was found, and the respective values for liver and kidney were 0.92 and 0.77. An extension of the reliability model to account for individual inactivation probability of the subunits allows calculation of complication probability for inhomogeneous dose distributions. For the brain, intercomparisons of a three-field and a two-field technique demonstrated a small reduction in complication probability for the former at low total doses. At high total doses a minimum complication probability was achieved applying a three-field technique, being three times less than that associated with the two-field technique. (author)
Jalbout, Abraham F.; Li, Xin-Hua; Abou-Rachid, Hakima
The molecular spectroscopic constants for the chalcogenide complexes MX (M dbond Ge, Sn, Pb; X dbond O, S, Se, Te, Po) and their corresponding MX- anions are presented with the LSDA/SDD, B1LYP/SDD, and B3LYP/SDD methods. Although many methods were attempted, only the most promising results are reported. We show that the best results are obtained by LSDA/SDD calculations, and thus this method is emphasized as an illustrative example of our methodology. The potential energy curves and physical property characterizations for X1 ?+ state of LuH and LuF are presented with a variety of density functional theory (DFT) methods. Comparisons with wave function-based treatments (HF, MP2, CCSD, QCISD) are made in addition to experimental correlations. We show that the best results are obtained by the B3LYP/SDD method for LuH, and the MPW1PW91/SDD method for LuF.
Dielectric Constant of Suspensions of Blood Cells
Mendelson, Kenneth; Ackmann, James
1996-03-01
Measurements of the complex dielectric constant of suspensions of blood cells have recently been reported by Ackmann, et al.(J. J. Ackmann, et al., Ann. Biomed. Eng. 24), 58 (1996). At frequencies below 100 kHz, the real part of the dielectric constant (ɛ') goes through a maximum at a blood cell volume fraction of about 70%. Effective medium approximations do not agree well with this behavior. As a more realistic model, we are studying the grain consolidation model of Roberts and Schwartz(J. N. Roberts and L. M. Schwartz, Phys. Rev. B 31), 5990 (1985). We have used a finite element method to calculate the dielectric constant of this model for a cubic array of spheres. The simulations agree remarkably well with experiment. They suggest, however, that ɛ' may be showing oscillations rather than a simple maximum. Comparison of the simulated and experimental points suggests that this is not an artifact of the periodic array used in the model. Furthermore the simulations indicate that the maximum (or oscillations) disappears at low conductivities of the suspending fluid.
Pressure Dependence of Molar Volume near the Melting Point in Benzene
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.
Jincai Wang
2007-01-01
We introduce the \\(J\\)-convexity constants on Banach spaces and give some properties of the constants. We give the relations between the \\(J\\)-convexity constants and the \\(n\\)-th von Neumann-Jordan constants. Using the quantitative indices we estimate the value of \\(J\\)-convexity constants in Orlicz spaces.
Stresses and elastic constants of crystalline sodium, from molecular dynamics
International Nuclear Information System (INIS)
The stresses and the elastic constants of bcc sodium are calculated by molecular dynamics (MD) for temperatures to T = 340K. The total adiabatic potential of a system of sodium atoms is represented by pseudopotential model. The resulting expression has two terms: a large, strictly volume-dependent potential, plus a sum over ion pairs of a small, volume-dependent two-body potential. The stresses and the elastic constants are given as strain derivatives of the Helmholtz free energy. The resulting expressions involve canonical ensemble averages (and fluctuation averages) of the position and volume derivatives of the potential. An ensemble correction relates the results to MD equilibrium averages. Evaluation of the potential and its derivatives requires the calculation of integrals with infinite upper limits of integration, and integrand singularities. Methods for calculating these integrals and estimating the effects of integration errors are developed. A method is given for choosing initial conditions that relax quickly to a desired equilibrium state. Statistical methods developed earlier for MD data are extended to evaluate uncertainties in fluctuation averages, and to test for symmetry. 45 refs., 10 figs., 4 tabs
MAHRAMANLIOĞLU, Mehmet; Ş. İsmail KIRBAŞLAR
2000-01-01
Densities, and refractive indices were measured for the binary system ethanol + 1-nonanol and ternary system ethanol + 1-nonanol + water at 293.15 K. The excess molar volumes, and the deviations molar refraction were calculated for binary and ternary system. Redlich-Kister type equation was fitted to the excess molar volumes and, the deviations from a mole fraction average of the molar refraction, and the values of coefficients were calculated
Institute of Scientific and Technical Information of China (English)
葛红光; 陈三平; 谢钢; 扬旭武; 高胜利; 史启祯
2006-01-01
A ternary solid complex Lu(Et2dtc)3(phen) has been obtained from the reaction of hydrated lutetiumchloride with sodium diethyldithiocarbamate (NaEt2dtc), and 1,10-phenanthroline (o-phen·H2O) in absolute ethanol. IR spectrum of the complex indicates that Lu3+ binds with sulfur atom in the Na (Et2dtc)3 and nitrogen atom in the o-phen. The enthalpy change of liquid-phase reaction of formation of the complex, △rHm(-)(1), was determined to be (-32.821 ± 0.147 ) Kj·mol-1 at 298.15 K by an RD-496 Ⅲ type heat conduction microcalormeter. The enthalpy change of the solid-phase reaction of formation of the complex, △rHm(-) (s), was calculated to be (104.160 ± 0.168) Kj · mol-1 on the basis of an appropriate thermochemistry cycle. The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature of liquid-phase reaction. Fundamental parameters, such as the activation enthalpy (△H(-)≠), the activation entropy (△S(-)≠), the activation free energy (△G≠(-)), the apparent reaction rate constant (k), the apparent activation energy (E), the pre-exponential constant (A) and the reaction order (n), were obtained by combination the reaction thermodynamic and kinetic equations with the data of thermokinetic experiments. The molar heat capacity of the complex, cm, was determined to be (82.23 ± 1.47) J·mol-1·K-1 by the same microcalormeter. The constant-volume combustion energy of the complex, △Cu, was determined as (-17 898.228 ± 8.59) Kj·mol-1 by an RBC-Ⅱ type rotating-bomb calorimeter at 298.15 K. Its standard enthalpy of combustion, △cHm(-), and standard enthalpy of formation, △fHm(-), were calculated to be (-17 917.43 ± 8.11) Kj·mol-1 and (-859.95 ±10.12) Kj·mol-1, respectively.
International Nuclear Information System (INIS)
Isothermal-isobaric Monte Carlo calculations were used to obtain predictions of the elastic coefficients and derived engineering moduli and Poisson ratios for crystalline hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The elastic coefficients were computed using the strain fluctuation formula due to Rahman and Parrinello [J. Chem. Phys. 76, 2662 (1982)]. Calculations were performed as a function of temperature (218 K≤T≤333 K) and hydrostatic pressure (0 GPa≤p≤4 GPa). The predicted values of the moduli and Poisson ratios under ambient conditions are in accord with general expectations for molecular crystals and with a very recent, unpublished determination for RDX. The moduli exhibit a sensitive pressure dependence whereas the Poisson ratios are relatively independent of pressure. The temperature dependence of the moduli is comparable to the precision of the results. However, the crystal does exhibit thermal softening for most pressures. An additional product of the calculations is information about the pressure-volume-temperature (pVT) equation of state. We obtain near-quantitative agreement with experiment for the case of hydrostatic compression and reasonable, but not quantitative, correspondence for thermal expansion. The results indicate a significant dependence of the thermal expansion coefficients on hydrostatic pressure. (c) 2000 American Institute of Physics
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Reinhardt, Michael J.; Joe, Alexius Y.; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger [Department of Nuclear Medicine, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Brink, Ingo [Department of Nuclear Medicine, University Hospital of Freiburg (Germany); Krause, Thomas M. [Department of Nuclear Medicine, Inselspital Bern (Switzerland)
2002-09-01
This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15{+-}9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256{+-}80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses
International Nuclear Information System (INIS)
On the basis of correct Hounsfield unit to electron density calibration, cone-beam computed tomography (CBCT) data provide the opportunity for retrospective dose recalculation in the patient. Therefore, the consequences of translational positioning corrections and of morphological changes in the patient anatomy can be quantified for prostate cancer patients. The organs at risk were newly contoured on the CBCT data sets of 7 patients so as to evaluate the actual applied dose. The daily dose to the planning target volume (PTV) was recalculated with and without the translation data, which result from the real patient repositioning. A CBCT-based dose recalculation with uncertainties less than 3 % is possible. The deviations between the planning CT and the CBCT without the translational positioning correction vector show an average dose difference of - 8 % inside the PTV. An inverse proportional relation between the mean bladder dose and the actual volume of the bladder could be established. The daily applied dose to the rectum is about 1-54 % higher than predicted by the planning CT. A dose calculation based on CBCT data is possible. The daily positioning correction of the patient is necessary to avoid an underdosage in the PTV. The new contouring of the organs at risk - the bladder and rectum - allows a better appraisal to be made of the total applied dose to these organs. (orig.)
THEORY OF PHYSICAL CONSTANTS AND SUPERGRAVITY IN 112D
Directory of Open Access Journals (Sweden)
Trunev A. P.
2016-04-01
Full Text Available In this article we discuss a version of the metric theory of the fundamental interactions in which it is assumed that the physical constants due to the presence of extra dimensions of space-time. The estimation of the number of physical constants based on the theory of supergravity in 112D is that the minimum number of constants is equal to 222, and the maximum number - 1404928. At present, the number of parameters that characterize the elementary particles, isotopes and chemical elements is about 150920. This number is 9.3 less than the maximum possible number of parameters that indicate still great potential of modern science. Functions describing the area and volume of a unit hypersphere, embedded in a Riemannian space of arbitrary dimension, were used to find the fundamental physical constants. A satisfactory agreement with a relative error of 0.03% calculated and experimental values of the fine structure constant found out. For the ratio of the average mass of a nucleon to the electron mass is obtained coincidence with the experimental value with an accuracy of 0.002%. The proposed theory of physical constants different from that Bartini theory that established the optimal dimension of the space is a hypersphere 5 and 7, rather than 6 as in Bartini theory. The problems of the compactification of extra dimensions in describing the motion in fourdimensional space-time are discussed
Energy Technology Data Exchange (ETDEWEB)
Fogt, H. [Technikum Joanneum, Fachhochschule-Studiengang Fahrzeugtechnik, Graz (Austria); Kneer, A. [Battelle Ingenieurtechnik GmbH, Eschborn (Germany); Seidel, V. [ICCM Inst. of Computational Continuum Mechanics GmbH, Hamburg (Germany)
1997-12-01
Apart from experimental and empirical methods, numerical calculations are increasingly being used for the examination and judging of two-phase flows and for the design of flow mechanics systems and components. Typical examples are injection systems, atomisers, mixers, steam-raising units and plants for smoke and exhaust gas cleaning. One frequently counteracts the long calculation times that occur in the numerical solution of two- or multi-phase equations by simplifying the assumptions. In energy and process technology, one often falls back on one-dimensional calculation procedures. This has the advantage that the behaviour of whole plants can be described by them the spatial and temporal resolution down to detecting small sale detail phenomena is only successful up to a point with these methods. Due to the constantly rising performance of the computers and by applying new mathematical/information methods, CFD methods make detailed numerical investigations of two-phase flow processes possible with reasonable computing times. The possibilities and limits are shown in the article by some examples. [Deutsch] Zur Untersuchung und Beurteilung von Zweiphasenstroemungen und fuer die Auslegung stroemungsmechanischer Systeme und Komponenten werden neben experimentellen und empirischen Methoden zunehmend numerische Rechenverfahren eingesetzt. Typische Beispiele sind Einspritzsysteme, Zerstaeuber, Mischer, Dampferzeuger und Anlagen zur Rauch- bzw. Abgasreinigung. Den hohen Rechenzeiten, die bei der numerischen Loesung der zwei- und mehrphasigen Erhaltungsgleichungen anfallen, wird haeufig durch Vereinfachung der Ansaetze entgegengewirkt. In der Enegie- und Verfahrenstechnik wird oft auf eindimensionale Rechenverfahren zurueckgegriffen. Sie bieten den Vorteil, dass mit ihnen das Verhalten ganzer Anlagen beschrieben werden kann. Die raeumliche und zeitliche Aufloesung bis hin zur Erfassung kleinskaliger Detailerscheinungen gelingt mit diesen Methoden nur bedingt. CFD Methoden
Cosmological Hubble constant and nuclear Hubble constant
International Nuclear Information System (INIS)
The evolution of the Universe after the Big Bang and the evolution of the dense and highly excited nuclear matter formed by relativistic nuclear collisions are investigated and compared. Values of the Hubble constants for cosmological and nuclear processes are obtained. For nucleus-nucleus collisions at high energies the nuclear Hubble constant is obtained in the frame of different models involving the hydrodynamic flow of the nuclear matter. Significant difference in the values of the two Hubble constant - cosmological and nuclear - is observed
Thickness and electric-field-dependent polarizability and dielectric constant in phosphorene
Kumar, Piyush; Bhadoria, B. S.; Kumar, Sanjay; Bhowmick, Somnath; Chauhan, Yogesh Singh; Agarwal, Amit
2016-05-01
Based on extensive first-principles calculations, we explore the thickness-dependent effective dielectric constant and slab polarizability of few-layer black phosphorene. We find that the dielectric constant in ultrathin phosphorene is thickness-dependent and it can be further tuned by applying an out-of-plane electric field. The decreasing dielectric constant with reducing number of layers of phosphorene is a direct consequence of the lower permittivity of the outer layers and the increasing surface-to-volume ratio. We also show that the slab polarizability depends linearly on the number of layers, implying a nearly constant polarizability per phosphorus atom. Our calculation of the thickness- and electric-field-dependent dielectric properties will be useful for designing and interpreting transport experiments in gated phosphorene devices, wherever electrostatic effects such as capacitance and charge screening are important.
Frequency Dependence of Attenuation Constant of Dielectric Materials
Directory of Open Access Journals (Sweden)
A. S. Zadgaonkar
1975-01-01
Full Text Available Different dielectric materials have been studied for frequency dependence of attenuation constant. The sensitive cathode ray oscillograph method has been used to evaluate to the dielectric constant and loss factor, and from these attenuation constants have been calculated. The temperature remaining constant, a regular increase has been observed in attenuation constant, at higher frequencies of electro-magnetic propagating wave.
International Nuclear Information System (INIS)
Aim: The fraction of ejection is one of the predictions factors more important after a acute heart attack and is essential its calculation in these patients. On the other hand the existence of residue ischemia is a basic information to predict the evolution and to decide the treatment about this pathology. The use of the Gated-Spect can contribute of simultaneous form both information. Our aim was to evaluate the utility of the fraction of ejection and of the volume end-diastolic of the left ventricle calculated by means of Gated-Spect as well as the relation that exists with the fact of the existence of scar in this images. Materials and Methods: 34 patients were studied (27 men and 7 women) sent to our service for accomplishment of Spect of myocardium perfusion for suspicion it diagnoses of heart attack of myocardium for present at least 2 of 3 clinical classic criteria (typical clinic, alterations ECG and increase enzymatic), to that was realized heart Gated-Spect with 925 MBq of Tc99-tetrofosmin after pharmacological stimulation with adenosine and 2 days later Spect with 333 MBq of the same tracer for acquisition of base images. Results: All the patients presented faults of perfusion fixed assimilable to zones of scar, finding in 13 of them certain degree of reversibility that was indicating existence of residue ischemia. The average of fraction of ejection was of 36.62% . Dividing by groups the fraction of ejection in the scar without ischemia ensued from 32.33% and in the scar with ischemia from 43.54%, being the difference between both groups significant statistically (P=0.003). For the volume end-diastolic the average belonged to 141.97 ml being divided in 157.90 ml for the pure scar and 116.23 ml for the scar with ischemia being this difference also significant (P=0.04) the relation is verified likewise between fraction of ejection and volume telediastolico with Pearson's coefficient between both variables of-0.79. Conclusion: According to our results the
Anderegg, G
2013-01-01
Critical Survey of Stability Constants of EDTA Complexes focuses on the computations, values, and characteristics of stability constants. The book emphasizes that for a critical discussion of experimentally determined stability constants, it is important to consider the precision of the values that manifests the self-consistency of the constant, taking into consideration the random errors. The publication reviews the stability constants of metal complexes. The numerical calculations affirm the reactions and transformations of metal ions when exposed to varying conditions. The text also present
一种预混燃烧加热式定容燃烧弹的研发%Development of a constant volume combustion bomb heated by premixed burning
Institute of Scientific and Technical Information of China (English)
邓鹏; 黄荣华; 张永林; 马寅杰
2013-01-01
An optical accessible constant volume combustion bomb was developed by the modular design concept to improve its adaptability and capability.This combustion bomb can meet the requirements for premixed combustion,spray evaporation,spray combustion,etc.To simulate the high pressure,high temperature and oxygen lean conditions occurred in advanced diesel engines,the ambient gas in the combustion bomb was heated by preburning of acetylene+oxygen mixture.Experiments show that this apparatus can simulate different spray combustion environments conveniently,the oxygen concentration ranges from 0％ to 21％,the ambient pressure ranges from 0.04 to 10.00 MPa and the ambient tempreature ranges from 300 to 1300 K.Spray atomization,evaporation and combustion process were studied in the apparatus using high speed schlieren method.Results show that this apparatus provides an essential prerequisite for studying issues related to vaporizing and combustion fuel spray in internal combustion engines.%为提高定容燃烧弹的适应性,增强其功能扩展潜力,采用模块化设计思想,研制出可满足预混燃烧、喷雾蒸发与燃烧等多种类型研究需求的可视化定容燃烧弹.为模拟内燃机缸内高温高压和氧体积分数可调的喷雾燃烧环境,采用乙炔+氧气预混合燃烧加热法,试验结果表明:该方法可方便快速地模拟出氧体积分数为0％～21％、环境压力为0.04～10.00MPa和环境温度为300～1300 K的喷雾燃烧环境;结合高速数字纹影法光学诊断系统,实现了对喷雾雾化过程、油气蒸发混合过程和喷雾着火燃烧过程的高速观测与记录;该试验平台为深入研究内燃机喷雾蒸发与燃烧过程提供了必要条件.
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
Energy Technology Data Exchange (ETDEWEB)
Debreczeny, M.P.
1994-05-01
We have measured and assigned rate constants for energy transfer between chromophores in the light-harvesting protein C-phycocyanin (PC), in the monomeric and trimeric aggregation states, isolated from Synechococcus sp. PCC 7002. In order to compare the measured rate constants with those predicted by Fdrster`s theory of inductive resonance in the weak coupling limit, we have experimentally resolved several properties of the three chromophore types ({beta}{sub 155} {alpha}{sub 84}, {beta}{sub 84}) found in PC monomers, including absorption and fluorescence spectra, extinction coefficients, fluorescence quantum yields, and fluorescence lifetimes. The cpcB/C155S mutant, whose PC is missing the {beta}{sub 155} chromophore, was, useful in effecting the resolution of the chromophore properties and in assigning the experimentally observed rate constants for energy transfer to specific pathways.
Energy Technology Data Exchange (ETDEWEB)
Kvinnsland, Y.; Skretting, A.; Bruland, Oe.S. [Department of Nuclear Medicine, The Norwegian Radium Hospital, 0310 Oslo (Norway)
2001-04-01
The purpose of the present work was to investigate how haematopoietic stem cell survival is affected by the differences in the dose distribution that arise from different radionuclides contained in bone-seeking radiopharmaceuticals. This was carried out in three steps: (a) calculations of representative dose distributions in individual bone marrow cavities that are irradiated by sources of {sup 89}Sr, {sup 186}Re, {sup 117}mSn or {sup 153}Sm, uniformly distributed on the bone surfaces; (b) assessment of the corresponding haematopoietic stem cell survival and (c) a comparison of these results with results obtained using the assumption of a uniform dose distribution. Two different idealized models of the geometry of trabecular bone were formulated, each consisting of an infinite array of identical elements. Monte Carlo simulations were used to generate dose-volume histograms that were used to assess haematopoietic stem cell survival with two different assumptions about spatial cell distributions. Compared with a homogeneous dose distribution, the estimated cell survival was markedly higher for {sup 117}mSn and {sup 153}Sm, and only slightly different for {sup 89}Sr and {sup 186}Re. The quantitative results differed between the two geometric models and the assumptions about spatial cell distribution, but the trends were the same. The results imply that it is necessary to include dose distributions for individual bone marrow cavities in considerations concerning bone marrow toxicity. (author)
First Principles Calculation of Elastic Constants of Monoclinic HfO2 Thin Film%单斜相HfO2薄膜弹性常数的第一性原理计算
Institute of Scientific and Technical Information of China (English)
蔺玲; 邵淑英; 李静平
2013-01-01
用电子束蒸发沉积在K9玻璃基底上镀制HfO2薄膜,沉积温度为200℃,蒸发速率为0.03 nm/s.由X射线衍射谱可知薄膜出现明显结晶,且为单斜相和正交相混合结构,其中单斜相占明显优势.用Jade5软件分析得到单斜相HfO2的晶格常数a,b,c以及晶格矢量a和c之间的夹角β.基于得到的晶格常数建立了单斜相HfO2薄膜的晶体结构模型.同时建立固态单斜相HfO2的晶体结构模型进行对比.通过密度泛函理论(DFT)框架下的平面超软赝势法,采用两种不同的交换关联函数:局域密度近似(LDA)中的CA-PZ和广义梯度近似(GGA)中的质子平衡方程(PBE),计算了薄膜态和固态单斜晶相HfO2的弹性刚度系数矩阵Gij和弹性柔度系数矩阵Sij,Reuss模型、Voigt模型和Hill理论下的体积模量和剪切模量,材料平均杨氏模量和泊松比.此外还计算得到薄膜态和固态单斜晶相HfO2在不同方向上的杨氏模量.%HfO2 films are deposited by electron beam evaporation at a deposition rate of 0.03 nm/s and deposition temperature of 200 ℃ on K9 glass substrates. The films are observed to show a mixed structure of monoclinic and orthorhombic phase through X-ray diffraction and monoclinic phase is of obvious advantages. The structure parameters a, b, c and angel β of monoclinic HfO2 films are obtained using Jade5 software, based on which the crystal structure model is built. While solid crystal monoclinic HfO2 model is built to compare with the thin film one. Elastic stiffness constants of monoclinic HfO2 thin film and solid crystal are investigated using the plane waves ultrasoft pseudopotential technique based on the density functional theory (DFT) under two different exchange correlation functions of local density approximation (LDA) CA-PZ and generalized gradient approximation (GGA) PBE. Reuss, Voigt and Hill theories are used to estimate the bulk, shear and average Young's moduli and Possion ratio for polycrystalline HfO2
Cosmological Constant, Fine Structure Constant and Beyond
Wei, Hao; Li, Hong-Yu; Xue, Dong-Ze
2016-01-01
In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. We propose two types of models to describe the evolutions of $\\Lambda$ and $\\alpha$. Then, we consider the observational constraints on these models, by using the 293 $\\Delta\\alpha/\\alpha$ data from the absorption systems in the spectra of distant quasars, and the data of type Ia supernovae (SNIa), cosmic microwave background (CMB), baryon acoustic oscillation (BAO). We find that the model parameters can be tightly constrained to the narrow ranges of ${\\cal O}(10^{-5})$ t...
Cosmological Constant and Soft Terms in Supergravity
Choi, Kiwoon; Kim, Jihn E.; Nilles, Hans Peter, Ramos-S\\xe1nchez, Sa\\xfal
1994-01-01
Some of the soft SUSY breaking parameters in hidden sector supergravity model depend on the expectation value of the hidden sector scalar potential, $$, whose tree level value is equal to the tree level cosmological constant. The current practice of calculating soft parameters assumes that $=0$. Quantum correction to the cosmological constant can differ from the correction to $$ by an amount of order $m^2_{3/2}M_{Pl}^2/8\\pi$. This implies that, for the vanishing cosmological constant, the $$-...
Physics without physical constants
International Nuclear Information System (INIS)
Following the general principles of both Newton's mechanics and Maxwell's electrodynamics, a new approach to basic equations of physics is presented. The new basic equations express fundamental laws of physics and are free from any physical constants. The necessary constants appear only through some kind of constitutive relations and by considering special solutions of the basic equations. The presented approach admits a new interpretation of fundamental physical constants, such as the Planck gravitational ones. 4 refs. (author)
Hydrolysis and formation constants at 250C
International Nuclear Information System (INIS)
A database consisting of hydrolysis and formation constants for about 20 metals associated with the disposal of nuclear waste is given. Complexing ligands for the various ionic species of these metals include OH, F, Cl, SO4, PO4 and CO3. Table 1 consists of tabulated calculated and experimental values of log K/sub xy/, mainly at 250C and various ionic strengths together with references to the origin of the data. Table 2 consists of a column of recommended stability constants at 250C and zero ionic strength tabulated in the column headed log K/sub xy/(0); other columns contain coefficients for an extended Debye-Huckel equation to permit calculations of stability constants up to 3 ionic strength, and up to 0.7 ionic strength using the Davies equation. Selected stability constants calculated with these coefficients for various ionic strengths agree to an average of +- 2% when compared with published experimental and calculated values
Directory of Open Access Journals (Sweden)
Carroll Sean M.
2001-01-01
Full Text Available This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero vacuum energy.
MUTLU, Reşat
2015-01-01
The memristor is a new-found circuit element and its applications in programmable circuits are also under study. Analysis of most of its combinations with other circuit elements such as resistors, capacitors, and inductors does not exist. In this work, a TiO$_{2}$ memristor model with linear dopant drift speed is used and the solution of a TiO$_{2}$ memristor and capacitor series circuit driven by a constant voltage source is given. It is then used to analyze a novel M-C oscillator circuit. I...
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The main problem,in determining the shear displacement of a general shear zone with volume change using the available formula,is that it is hard to know the initial angle between the planes (or lines) in the plane of shear.A planar deformation analysis of this kind of ductile shear zone is carried out with the polar Mohr diagram.If the volume change is induced by homogeneous contraction in the Z direction of the shear zone,there are sufficient conditions for constructing a polar Mohr diagram regardless of sequence of the simple shear and volume change.Therefore,the angle between a line and the shear direction before and after the deformation can be measured.Making use of these lines the shear strain and the volume change can be calculated and the shear displacement can be determined.
Institute of Scientific and Technical Information of China (English)
李海; 郭召杰; 刘瑞洵; 刘树文; 张志诚
2000-01-01
The main problem, in determining the shear displacement of a general shear zone with volume change using the available formula, is that it is hard to know the initial angle between the planes (or lines) in the plane of shear. A planar deformation analysis of this kind of ductile shear zone is carried out with the polar Mohr diagram. If the volume change is induced by homogeneous contraction in the Z direction of the shear zone, there are sufficient conditions for constructing a polar Mohr diagram regardless of sequence of the simple shear and volume change. Therefore, the angle between a line and the shear direction before and after the deformation can be measured. Making use of these lines the shear strain and the volume change can be calculated and the shear displacement can be determined.
Elastic Constants of Superconducting MgB2 from Molecular Dynamics Simulations with Shell Model
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
The elastic constants of superconducting MgB2 are calculated using a molecular dynamics method (MD)with shell model. The lattice parameters, five independent elastic constants, equations of state (EOS), Debye temperature, and bulk modulus of MgB2 are obtained. Meanwhile, the dependence of the bulk modulus B, the lattice parameters a and c, and the unit cell volume V on the applied pressure are presented. It is demonstrated that the method introduced here can well reproduce the experimental results with a reasonable accuracy.
Reactor group constants and benchmark test
International Nuclear Information System (INIS)
The evaluated nuclear data files such as JENDL, ENDF/B-VI and JEF-2 are validated by analyzing critical mock-up experiments for various type reactors and assessing applicability for nuclear characteristics such as criticality, reaction rates, reactivities, etc. This is called Benchmark Testing. In the nuclear calculations, the diffusion and transport codes use the group constant library which is generated by processing the nuclear data files. In this paper, the calculation methods of the reactor group constants and benchmark test are described. Finally, a new group constants scheme is proposed. (author)
Kapelner, Adam; Krieger, Abba; Blanford, William J.
2016-01-01
When measuring Henry's Law constants ($k_H$) using the phase ratio method via headspace gas chromatography (GC), the value of $k_H$ of the compound under investigation is calculated from the ratio of the slope to the intercept of a linear regression of the the inverse GC response versus the ratio of gas to liquid volumes of a series of vials drawn from the same parent solution. Thus, an experimenter will collect measurements consisting of the independent variable (the gas/liquid volume ratio)...
Volume of ionic sites in silicate glasses
International Nuclear Information System (INIS)
Molar volume data of alkali and alkaline earth silicate glasses have been used to calculate the free volume associated with the bridging and nonbridging oxygen and modifier ions. The free volume associated with the bridging oxygen is constant (15.39 x 10-24 cm3) for all modifier ions up to 33.3 mol% modifier oxide. It decreases (in alkali or alkaline earth silicate glasses) with increasing number of nonbridging oxygen ions per structural unit and/or radius of the modifier ion. The nonbridging oxygen ion is associated with a constant free volume (6.50 x 10-24 cm3) in all cases. Modifier ions are associated with free volume that increases with increasing number of nonbridging oxygen ions per structural unit and/or radius of the modifier ion. The used model explores the change in the free volume due to changing the concentration of alkali oxides in mixed alkali silicate glasses. The results show that, in such glasses, the free volume related to a certain type of alkali oxide increases with increasing content
International Nuclear Information System (INIS)
We investigated whether right atrial (RA) volume could be used to predict the recurrence of atrial fibrillation (AF) after pulmonary vein catheter ablation (CA). We evaluated 65 patients with paroxysmal AF (mean age, 60+10 years, 81.5% male) and normal volunteers (57±14 years, 41.7% male). Sixty-four-slice multi-detector computed tomography was performed for left atrial (LA) and RA volume estimations before CA. The recurrence of AF was assessed for 6 months after the ablation. Both left and right atrial volumes were larger in the AF patients than the normal volunteers (LA: 99.7+33.2 ml vs. 59.7+17.4 ml; RA: 82.9+35.7 ml vs. 43.9+12 ml; P100 ml) for predicting the recurrence of AF was 81.3% in 13 of 16 patients with AF recurrence, and the specificity was 69.4% in 34 of 49 patients without recurrence. The sensitivity with large RA volumes (>87 ml) was 81.3% in 13 of 16 patients with AF recurrence, and the specificity was 75.5% in 37 of 49 patients without recurrence. RA volume is a useful predictor of the recurrence of AF, similar to LA volume. (author)
Institute of Scientific and Technical Information of China (English)
田爱琴; 孙洪博; 陈文涛; 王琳
2012-01-01
Based on vapor-liquid phase equilibria data for CO2+2-butanol binary system from 323K to 353K by constant-volume visual high-pressure cell, the solubility model of CO2 in 2-butanol was established with Krichevsky-Kasarnovsky equation. Henry's coefficients and partial molar volumes of CO2 at infinite dilution were calculated. Meanwhile, Partial molar volumes of CO2 and 2-butanol at equilibrium were calculated from partial molar volumes properties together with Peng-Robinson equation of state and Van der Waals-2 mixed rule. The results showed that Henry's coefficients and partial molar volumes of CO2 at infinite dilution were both the function of temperature, and Henry's coefficients decreased with temperature. The partial molar volumes of CO2 at infinite dilution were negative and the magnitudes decreased with temperature. The calculated effects of partial molar volumes of vapor and liquid phase at equilibrium showed that the partial molar volumes of CO2 and 2-butanol in liquid phase were positive, but in vapor the partial molar volumes of CO2 were negative and the partial molar volumes of 2-butanol were positive. The research provided theoretical basis for deciding supercritical extraction conditions and instructing industrial production.%利用固定体积可视高压釜测量出的在323 K～353 K温度范围内的CO2与2-丁醇二元体系在高压下的汽液相平衡数据,根据Krichevsky-Kasarnovsky方程建立了CO2在液相中的溶解度模型,得到了该二元体系在高压下的亨利系数和CO2在无限稀释溶液中的偏摩尔体积等性质.同时根据偏摩尔体积性质和Peng-Robinson状态方程及Van der Waals-2混合规则来计算该体系在平衡状态下的气、液相的偏摩尔体积.结果表明CO2在2-丁醇中的亨利系数和CO2在无限稀释溶液中的偏摩尔体积均为温度的函数,CO2在2-丁醇中的亨利系数随温度的升高而降低.CO2在无限稀释溶液中的偏摩尔体积(V)1∞在研究温度下均为
The Alpha Constant from Relativistic Groups
González-Martin, G R
2000-01-01
The value of the alpha constant, known to be equal to an algebraic expression in terms of pi and entire numbers related to certain group volumes, is derived from the relativistic structure group of a geometric unified theory, its subgroups and corresponding symmetric space quotients.
Institute of Scientific and Technical Information of China (English)
张文明
2011-01-01
To solve the problem of torque decrease at low or high speed,a new three-phase hybrid stepper motor drive was developed. All the hardware circuit and software program of the drive were presented. With the new device,the hardware circuit parameters,critical data and software design were analyzed in detail. Meanwhile a comprehesive explanation of the PLC,logic control,constant cruuent control,high voltage drive,current sampling,over current protection and power supply ciruit was put forward, which is of a certain reference value.%针对步进电动机在低速和高速转矩下降的问题,开发出一种新型三相混合式步进电动机驱动器.给出驱动器全部硬件电路和软件程序,结合新器件应用,对硬件电路参数、关键数据、软件设计进行详实分析,全面剖析了单片机、逻辑控制、恒流控制、高压驱动、电流采样、过压保护、供电电源电路等,具有一定参考价值.
1995-08-01
about the distances to galaxies and thereby about the expansion rate of the Universe. A simple way to determine the distance to a remote galaxy is by measuring its redshift, calculate its velocity from the redshift and divide this by the Hubble constant, H0. For instance, the measured redshift of the parent galaxy of SN 1995K (0.478) yields a velocity of 116,000 km/sec, somewhat more than one-third of the speed of light (300,000 km/sec). From the universal expansion rate, described by the Hubble constant (H0 = 20 km/sec per million lightyears as found by some studies), this velocity would indicate a distance to the supernova and its parent galaxy of about 5,800 million lightyears. The explosion of the supernova would thus have taken place 5,800 million years ago, i.e. about 1,000 million years before the solar system was formed. However, such a simple calculation works only for relatively ``nearby'' objects, perhaps out to some hundred million lightyears. When we look much further into space, we also look far back in time and it is not excluded that the universal expansion rate, i.e. the Hubble constant, may have been different at earlier epochs. This means that unless we know the change of the Hubble constant with time, we cannot determine reliable distances of distant galaxies from their measured redshifts and velocities. At the same time, knowledge about such change or lack of the same will provide unique information about the time elapsed since the Universe began to expand (the ``Big Bang''), that is, the age of the Universe and also its ultimate fate. The Deceleration Parameter q0 Cosmologists are therefore eager to determine not only the current expansion rate (i.e., the Hubble constant, H0) but also its possible change with time (known as the deceleration parameter, q0). Although a highly accurate value of H0 has still not become available, increasing attention is now given to the observational determination of the second parameter, cf. also the Appendix at the
Energy Technology Data Exchange (ETDEWEB)
Howerton, R.J.; MacGregor, M.H.
1978-05-17
Descriptions of evaluated nuclear data sets for 86 isotopes in the range Z = 0 to 98 are presented. The evaluation procedures that were used are discussed. At the beginning of the discussion for each individual isotope, a computer-generated listing is given which summarizes the main properties of the data sets that are contained in the evaluation.
Indian Academy of Sciences (India)
B P Pandey; V Kumar; Eduardo Menendez Proupin
2014-09-01
First-principles calculations were performed to study the elastic stiffness constants ($C_{ij}$) and Debye temperature ($_D$) of wurzite (wz) AlN and GaN binary semiconductors at high pressure. The lattice constants were calculated from the optimized structure of these materials. The band gaps were calculated at point using local density approximation (LDA) approach. The unit cell volume, lattice parameters, /, internal parameter (), elastic constant ($C_{ij}$), Debye temperature ($_D$), Hubbard parameter () and band gap ($E_g$) were studied under different pressures. The bulk modulus ($B_0$), reduced bulk modulus ($B'_0$) and Poisson ratio ($\\vee$) were also calculated. The calculated values of these parameters are in fair agreement with the available experimental and reported values.
Energy Technology Data Exchange (ETDEWEB)
Rojas C, E. L. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)
2008-07-01
The objective of this study is to investigate the changes observed in the absorbed doses in mammary gland tissue when irradiated with a equipment of high dose rate known as Mammosite and introducing material resources contrary to the tissue that constitutes the mammary gland. The modeling study is performed with the code MCNPX, 2005 version, the equipment and the mammary gland and calculating the absorbed doses in tissue when introduced small volumes of air or calcium in the system. (Author)
International Nuclear Information System (INIS)
Statistical shape fluctuations can be calculated with two alternative assumptions: (a) the temperature remains constant as the shape fluctuates, or (b) the energy remains constant as the shape fluctuates. These two possibilities are compared for a simple model, the Landau theory, and the finite-temperature HFB cranking theory. Average electric quadrupole moments are compared for these two constraints. (orig.)
International Nuclear Information System (INIS)
The method of homogeneous deformation has been applied to obtain theoretical expressions for the second order elastic (SOE) and third order elastic (TOE) constants of an ideal dhcp lattice. Two body interactions alone have been considered between the origin atom and six other kinds of atoms. The expressions obtained for the TOE constants have been employed to calculate the TOE constants for the metals Pr and Nd whose c to a ratio is very nearly equal to the ideal value. The Anderson-Grueneisen parameter for the two metals is calculated using their respective TOE constants. Anderson's theory is used to calculate the temperature dependence of the bulk modulus Bsub(S) for these two metals and is compared with the experimental values. The agreement is good. The low temperature limit of the volume Grueneisen function has been obtained using the respective theoretical TOE constants of these two metals. The variation of a/a0 and v/v0 with hydrostatic pressure up to 100 kbar has been calculated using the theoretical TOE constants and Thurston's extrapolation formula for both Pr and Nd. (Auth.)
The relative volume growth of minimal submanifolds
DEFF Research Database (Denmark)
Markvorsen, Steen; Palmer, V.
2002-01-01
The volume growth of certain well-defined subsets of minimal submanifolds in riemannian spaces are compared with the volume growth of balls and spheres ill space forms of constant curvature.......The volume growth of certain well-defined subsets of minimal submanifolds in riemannian spaces are compared with the volume growth of balls and spheres ill space forms of constant curvature....
Owen, A. K.
1994-01-01
The laser anemometer has provided the fluid dynamicist with a powerful tool for nonintrusively measuring fluid velocities. One of the more common types of laser anemometers, the laser fringe anemometer, divides a single laser beam into two parallel beams and then focuses them on a point in space called the "probe volume" (PV) where the fluid velocity is measured. Many applications using this method for measuring fluid velocities require the observation of fluids through a window. The passage of the laser beams through materials having different indices of refraction has the following effects: 1) the position of the probe volume will change; 2) the beams will uncross, i.e., no longer lie in the same plane at the probe volume location; and 3) for nonflat plate windows, the crossing angle of the two beams will change. OPTMAIN uses a ray tracing technique, which is not restricted to special cases, to study the changes in probe volume geometry and position due to refraction effects caused by both flat and general smooth windows. Input parameters are the indices of refraction on both sides of the window and of the window itself, the window shape, the assumed position of the probe volume and the actual position of the focusing lens relative to the window, the orientation of the plane which contains the laser beams, the beam crossing angle, and the laser beam wavelength. OPTMAIN is written in FORTRAN 77 for interactive execution. It has been implemented on a DEC VAX 11/780 under VMS 5.0 with a virtual memory requirement of 50K. OPTMAIN was developed in 1987.
Anderson, L. R.; Miller, R. D.
1979-01-01
The LOADS computer program L218 which calculates dynamic load coefficient matrices utilizing the force summation method is described. The load equations are derived for a flight vehicle in straight and level flight and excited by gusts and/or control motions. In addition, sensor equations are calculated for use with an active control system. The load coefficient matrices are calculated for the following types of loads: (1) translational and rotational accelerations, velocities, and displacements; (2) panel aerodynamic forces; (3) net panel forces; and (4) shears, bending moments, and torsions.
Elastic constants of layers in isotropic laminates.
Heyliger, Paul R; Ledbetter, Hassel; Kim, Sudook; Reimanis, Ivar
2003-11-01
The individual laminae elastic constants in multilayer laminates composed of dissimilar isotropic layers were determined using ultrasonic-resonance spectroscopy and the linear theory of elasticity. Ultrasonic resonance allows one to measure the free-vibration response spectrum of a traction-free solid under periodic vibration. These frequencies depend on pointwise density, laminate dimensions, layer thickness, and layer elastic constants. Given a material with known mass but unknown constitution, this method allows one to extract the elastic constants and density of the constituent layers. This is accomplished by measuring the frequencies and then minimizing the differences between these and those calculated using the theory of elasticity for layered media to select the constants that best replicate the frequency-response spectrum. This approach is applied to a three-layer, unsymmetric laminate of WpCu, and very good agreement is found with the elastic constants of the two constituent materials. PMID:14649998
International Nuclear Information System (INIS)
According to improvement of SPECT system, ECG-gated SPECT with 201TlCl have been applied to the left ventricular volumetry. In this study 24 patients without ischemia demonstrated by stress (99mTc-TF) and rest (201TlCl) dual-isotope ECG-gated myocardial SPECT were enrolled. To evaluate left ventricular volumetry using 201Tl ECG-gated SPECT data, the left ventricular end diastolic volumes (EDV) were compared between Quantitative Gated SPECT (QGS) and Emory Cardiac Toolbox (ECT) as well as between dual-isotopes based on the same ECG-gated data. The EDV values with 99mTc data (EDVTc) using QGS were well correlated with those using ECT (r=0.96, pTc (r=0.98, p201Tl (EDVTl) (r=0.93, pTl compared with EDVTc. In contrast, EDVTl were significantly higher than EDVTc in ECT performance. The QGS errors subtracting EDVTl from EDVTc were more evident according to the left ventricular volume increase. On the other hand, ECT error showed no tendency associated with the left ventricular volume. From these results, a careful strategy for selection of tracers and softwares should be necessary to assessment of quantitative values derived from ECG-gated SPECT data because of interaction with softwares, tracers, and subjects. (author)
Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher
Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie
2015-01-01
Purpose To determine if the lens volume changes during accommodation. Methods The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. Results The mean (±SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were −0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Conclusions Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule. PMID:26161985
Perdomo, Oscar M
2013-01-01
In this paper we show all possible ramps where an object can move with constant speed under the effect of gravity and friction. The planar ramp are very easy to describe, just rotate a curve with velocity vector (tanh(as),sech(as)). Recall that tanh(as)^2+sech^2(as) = 1. Therefore, the solution of the planar constant speed problem is connected with easy to describe examples of curves with arc-length parameter. For ramps in the space, we show that there are as many ramps as tangent unit vector fields in the south hemisphere. A video explaining these results can be found at http://www.youtube.com/watch?v=iBrvbb0efVk
Variation of fundamental constants
Flambaum, V V
2006-01-01
We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.
The cosmological constant puzzle
Bass, Steven D.
2011-01-01
Abstract The accelerating expansion of the Universe points to a small positive vacuum energy density and negative vacuum pressure. A strong candidate is the cosmological constant in Einstein's equations of General Relativity. Possible contributions are zero-point energies and the condensates associated with spontaneous symmetry breaking. The vacuum energy density extracted from astrophysics is 10 56 times smaller than the value expected from quantum fields and Standard Model particle physi...
International Nuclear Information System (INIS)
Small fluctuations in the solar constant can occur on timescales much shorter than the Kelvin time. Changes in the ability of convection to transmit energy through the superadiabatic and transition regions of the convection zone cause structure adjustments which can occur on a time scale of days. The bulk of the convection zone reacts to maintain hydrostatic equilibrium (though not thermal equilibrium) and causes a luminosity change. While small radius variations will occur, most of the change will be seen in temperature
Energy Technology Data Exchange (ETDEWEB)
Beres, D.A.; Hull, A.P.
1991-12-01
DEPDOSE is an interactive, menu driven, microcomputer based program designed to rapidly calculate committed dose from radionuclides deposited on the ground. The program is designed to require little or no computer expertise on the part of the user. The program consisting of a dose calculation section and a library maintenance section. These selections are available to the user from the main menu. The dose calculation section provides the user with the ability to calculate committed doses, determine the decay time needed to reach a particular dose, cross compare deposition data from separate locations, and approximate a committed dose based on a measured exposure rate. The library maintenance section allows the user to review and update dose modifier data as well as to build and maintain libraries of radionuclide data, dose conversion factors, and default deposition data. The program is structured to provide the user easy access for reviewing data prior to running the calculation. Deposition data can either be entered by the user or imported from other databases. Results can either be displayed on the screen or sent to the printer.
Exact marginals and normalizing constant for Gibbs distributions
Hardouin, Cécile; Guyon, Xavier
2010-01-01
International audience We present a recursive algorithm for the calculation of the marginal of a Gibbs distribution $\\pi$. A direct consequence is the calculation of the normalizing constant of$\\pi$.
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
Energy Technology Data Exchange (ETDEWEB)
Isambert, A.; Lefkopoulos, D. [Institut Gustave-Roussy, Medical Physics Dept., 94 - Villejuif (France); Brualla, L. [NCTeam, Strahlenklinik, Universitatsklinikum Essen (Germany); Benkebil, M. [DOSIsoft, 94 - Cachan (France)
2010-04-15
Purpose of study Monte Carlo based treatment planning system are known to be more accurate than analytical methods for performing absorbed dose estimation, particularly in and near heterogeneities. However, the required computation time can still be an issue. The present study focused on the determination of the optimum statistical uncertainty in order to minimise computation time while keeping the reliability of the absorbed dose estimation in treatments planned with electron-beams. Materials and methods Three radiotherapy plans (medulloblastoma, breast and gynaecological) were used to investigate the influence of the statistical uncertainty of the absorbed dose on the target volume dose-volume histograms (spinal cord, intra-mammary nodes and pelvic lymph nodes, respectively). Results The study of the dose-volume histograms showed that for statistical uncertainty levels (1 S.D.) above 2 to 3%, the standard deviation of the mean dose in the target volume calculated from the dose-volume histograms increases by at least 6%, reflecting the gradual flattening of the dose-volume histograms. Conclusions This work suggests that, in clinical context, Monte Carlo based absorbed dose estimations should be performed with a maximum statistical uncertainty of 2 to 3%. (authors)
Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide
DEFF Research Database (Denmark)
Kjær, Hanna; Nielsen, Monia R.; Pagola, Gabriel I.;
2012-01-01
In this paper we present the so far most extended investigation of the calculation of the coupling constant polarizability of a molecule. The components of the coupling constant polarizability are derivatives of the NMR indirect nuclear spin-spin coupling constant with respect to an external elec...
Giordano, Guido; De Benedetti, Arnaldo Angelo; Bonamico, Andrea; Ramazzotti, Paolo; Mattei, Massimo
2014-01-01
The Quaternary Roman Volcanic Province extends for over 200 km along the Tyrrhenian margin of the Italian peninsula and is composed of several caldera complexes with significant associated geothermal potential. In spite of the massive programs of explorations conducted by the then state-owned ENEL and AGIP companies between the 1970s and 1990s, and the identification of several high enthalpy fields, this resource remains so far unexploited, although it occurs right below the densely populated metropolitan area of Roma capital city. The main reason for this failure is that deep geothermal reservoirs are associated with fractured rocks, the secondary permeability of which has been difficult to predict making the identification of the most productive volumes of the reservoirs and the localisation of productive wells uncertain. As a consequence, almost half of the many exploration deep bore-holes drilled in the area reached a dry target. This work reviews available data and re-assesses the geothermal potential of caldera-related systems in Central Italy, by analysing in detail the case of the Colli Albani caldera system, the closest to Roma capital city. A GIS based approach identifies the most promising reservoir volumes for geothermal exploitation and uses an improved volume method approach for the evaluation of geothermal potential. The approach is based on a three dimensional matrix of georeferenced spatial data; the A axis accounts for the modelling of the depth of the top of the reservoirs based on geophysical and direct data; the B axis accounts for the thermal modelling of the crust (i.e. T with depth) based on measured thermal gradients. Both A and B data are necessary but not sufficient to identify rock volumes actually permeated by geothermal fluids in fractured reservoirs. We discuss the implementation of a C axis that evaluates all surface data indicating permeability in the reservoir and actual geothermal fluid circulation. We consider datasets on: i
Directory of Open Access Journals (Sweden)
Neal Jackson
2015-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
Approximations to Euler's constant
International Nuclear Information System (INIS)
We study a problem of finding good approximations to Euler's constant γ=lim→∞ Sn, where Sn = Σk=Ln (1)/k-log(n+1), by linear forms in logarithms and harmonic numbers. In 1995, C. Elsner showed that slow convergence of the sequence Sn can be significantly improved if Sn is replaced by linear combinations of Sn with integer coefficients. In this paper, considering more general linear transformations of the sequence Sn we establish new accelerating convergence formulae for γ. Our estimates sharpen and generalize recent Elsner's, Rivoal's and author's results. (author)
Kepler's Constant and WDS Orbit
Siregar, S
2012-01-01
The aim of this work are to find a Kepler's constant by using polynomial regression of the angular separation \\rho = \\rho(t) and the position angle \\theta = \\theta(t). The Kepler's constant obtained is used to derive the element of orbit. As a case study the angular separation and the position angle of the WDS 00063 +5826 and the WDS 04403-5857 were investigated. For calculating the element of orbit the Thiele-Innes van den Bos method is used. The rough data of the angular separation \\rho(t) and the position angle \\theta(t) are taken from the US Naval Observatory, Washington. This work also presents the masses and absolute bolometric magnitudes of each star.These stars include into the main-sequence stars with the spectral class G5V for WDS04403-5857and the type of spectrum G3V for WDS 00063+5826. The life time of the primary star and the secondary star of WDS 04403-5857 nearly equal to 20 Gyr. The life time of the primary star and the secondary star of WDS 00063+5826 are 20 Gyr and 19 Gyr, respectively.
DEFF Research Database (Denmark)
Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.
2013-01-01
A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power...
Institute of Scientific and Technical Information of China (English)
李云春; 李敬民; 马文杰; 王瑞; 陈双红
2013-01-01
在工程造价工作中，有关钢筋工程量的枯燥的平法表示法和繁琐的计算往往令初学者望而生畏，甚至失去了学习的兴趣。本文主要通过 Flash 强大的动画演示功能和内置的 AcionScript 脚本语言，以一根框架梁为例，将平淡无奇的钢筋平法图形像动画一样生动、形象地展示出来，并配以文字说明与计算方法，让钢筋工程量计算的学习变得简单易学，并较大程度地增强学习者的学习兴趣。%In the administration of engineering cost, students often have difficulties in P -method expression and cumbersome calculations of reinforced concrete construction volume, even lost interest in learning. Taking a frame girder as an example, the paper shows the P-method figure through Flashi and built-in AcionScript scripting language, with a text description and calculation methods; it makes calculation of reinforced concrete construction volume simply and easy, and enhances students ' interest in learning.
Big bang nucleosynthesis constraints on universal extra dimensions and varying fundamental constants
International Nuclear Information System (INIS)
The successful prediction of light element abundances from big bang nucleosynthesis (BBN) has been a pillar of the standard model of cosmology. Because many of the relevant reaction rates are sensitive to the values of fundamental constants, such as the fine structure constant and the strong coupling constant, BBN is a useful tool to probe and to put constraints on possible cosmological variations of these constants, which arise naturally from many versions of extra-dimensional theories. In this paper, we study the dependences of fundamental constants on the radion field of the universal extra-dimension model, and calculate the effects of such varying constants on BBN. We also discuss the possibility that the discrepancy between BBN and the Wilkinson Microwave Anisotropy Probe (WMAP) data on the baryon-to-photon ratio can be reduced if the volume of the extra dimensions was slightly larger--by O(10-3)--at the BBN era compared to its present value, which would result in smaller gauge couplings at BBN by the same factor
De Beni, E.; Behncke, B.; Branca, S.; Nicolosi, I.; Carluccio, R.; D'Ajello Caracciolo, F.; Chiappini, M.
2015-09-01
During the years 2013-2014, the New Southeast Crater (NSEC) at the summit of Mount Etna produced frequent episodes of lava fountaining (paroxysms), and its cone continued to grow at unprecedented rates. Many of the episodes were of rather brief duration and violently explosive, producing mostly pyroclastic material and minor volumes of lava. Other episodes, especially those since mid-December 2013, were characterized by violent Strombolian activity without producing sustained lava fountains and significant amounts of tephra, but emitting more voluminous lava flows. One episode of intense Strombolian and effusive activity that was possibly fed from the NSEC conduit occurred from vents located approximately 1 km north of the crater, on the east flank of the Northeast Crater, in July-August 2014. The evolution of the NSEC cone between 2012 and 2014 was documented by repeated GPS surveys carried out both from a distance and on the cone itself, by the acquisition of comparison photographs, and by two aerophotogrammetric surveys. From these surveys the highest point of the NSEC results to have grown from 190 m (May 2012) to ̴215 m (October 2014) above the pre-cone surface reaching an elevation of 3290 m, and its volume more than doubled to ̴ 50.0 ± 6.5 × 106 m3, representing the 40% of the total (bulk) volume of the volcanic products including pyroclastic fallout erupted in 2011-2014, which is 147.2 × 106 m3 (101.3 × 106 m3 dense-rock equivalent). The whole of the 2011-2014 NSEC activity marks an unusually high frequency of rather explosive, tephra-rich eruptive episodes compared to Etna's activity in past decades and centuries, although the average magma production rate in this interval is close to the supposed long-term output rate of the volcano. The latest eruptive episodes show a tendency of the NSEC coalescing with the old Southeast Crater cone, which therefore represents a miniature example of a growing compound volcano at the summit of Etna.
Directory of Open Access Journals (Sweden)
Ayman A. Lawama
2008-01-01
Full Text Available Flight safety is of a major concern in aircrafts since the beginning of air traffic. One of the problems threatening the safety is the in-flight icing of the aircraft. This research deals with a problem arises in the context of weather aviation maintenance. Methods of aircraft icing are based on the difference in behavior of the polarization of radar signal in case of water clouds, ice clouds and their mixed ensembles. The study investigates the mathematical models for some effects on wave propagation in cloudy atmosphere. They are used to calculate the polarimetric measurable variables as an indicator of remote sensing of clouds and precipitation. The differential reflectivity (ZDR and Linear depolarization ratio (LDR both are essential to calculate the Radar Cross Section (RCS at different polarization and hydrometeors parameters. The results give the basis for development of algorithms for detection of zones in clouds where aircraft icing is characterized by high probability.
Experimental determination of the effective strong coupling constant
Energy Technology Data Exchange (ETDEWEB)
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2005-09-15
We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
International Nuclear Information System (INIS)
We examine some novel physical consequences of the general structure of moduli spaces of string vacua. These include (1) finiteness of the volume of the moduli space and (2) chaotic motion of the moduli in the early universe. To fix ideas we examine in detail the example of the (conjectural) dilaton-axion ''S-duality'' of four-dimensional string compactifications. The facts (1) and (2) together might help to solve some problems with the standard scenarios for supersymmetry breaking and vacuum selection in string theory. ((orig.))
Energy Technology Data Exchange (ETDEWEB)
Primm III, RT
2002-05-29
This volume of the progress report provides documentation of reactor physics and criticality safety studies conducted in the US during fiscal year 1997 and sponsored by the Fissile Materials Disposition Program of the US Department of Energy. Descriptions of computational and experimental benchmarks for the verification and validation of computer programs for neutron physics analyses are included. All benchmarks include either plutonium, uranium, or mixed uranium and plutonium fuels. Calculated physics parameters are reported for all of the computational benchmarks and for those experimental benchmarks that the US and Russia mutually agreed in November 1996 were applicable to mixed-oxide fuel cycles for light-water reactors.
Calculating Henry’s Constants of Charged Molecules Using SPARC
SPARC Performs Automated Reasoning in Chemistry is a computer program designed to model physical and chemical properties of molecules solely based on thier chemical structure. SPARC uses a toolbox of mechanistic perturbation models to model intermolecular interactions. SPARC has ...
Constant Proportion Portfolio Insurance
DEFF Research Database (Denmark)
Jessen, Cathrine
2014-01-01
Portfolio insurance, as practiced in 1987, consisted of trading between an underlying stock portfolio and cash, using option theory to place a floor on the value of the position, as if it included a protective put. Constant Proportion Portfolio Insurance (CPPI) is an option-free variation on the...... theme, originally proposed by Fischer Black. In CPPI, a financial institution guarantees a floor value for the “insured” portfolio and adjusts the stock/bond mix to produce a leveraged exposure to the risky assets, which depends on how far the portfolio value is above the floor. Plain-vanilla portfolio...... insurance largely died with the crash of 1987, but CPPI is still going strong. In the frictionless markets of finance theory, the issuer’s strategy to hedge its liability under the contract is clear, but in the real world with transactions costs and stochastic jump risk, the optimal strategy is less obvious...
Energy Technology Data Exchange (ETDEWEB)
Beiu, V.
1997-04-01
In this paper the authors discuss several complexity aspects pertaining to neural networks, commonly known as the curse of dimensionality. The focus will be on: (1) size complexity and depth-size tradeoffs; (2) complexity of learning; and (3) precision and limited interconnectivity. Results have been obtained for each of these problems when dealt with separately, but few things are known as to the links among them. They start by presenting known results and try to establish connections between them. These show that they are facing very difficult problems--exponential growth in either space (i.e. precision and size) and/or time (i.e., learning and depth)--when resorting to neural networks for solving general problems. The paper will present a solution for lowering some constants, by playing on the depth-size tradeoff.
Decay constants in geochronology
Institute of Scientific and Technical Information of China (English)
IgorM.Villa; PaulR.Renne
2005-01-01
Geologic time is fundamental to the Earth Sciences, and progress in many disciplines depends critically on our ability to measure time with increasing accuracy and precision. Isotopic geochronology makes use of the decay of radioactive nuclides as a help to quantify the histories of rock, minerals, and other materials. Both accuracy and precision of radioisotopic ages are, at present, limited by those of radioactive decay constants. Modem mass spectrometers can measure isotope ratios with a precision of 10-4 or better. On the other hand, the uncertainties associated with direct half-life determinations are, in most cases, still at the percent level. The present short note briefly summarizes progress and problems that have been encountered during the Working Group's activity.
Directory of Open Access Journals (Sweden)
Jackson Neal
2007-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. In the last 20 years, much progress has been made and estimates now range between 60 and 75 km s^-1 Mpc^-1, with most now between 70 and 75 km s^-1 Mpc^-1, a huge improvement over the factor-of-2 uncertainty which used to prevail. Further improvements which gave a generally agreed margin of error of a few percent rather than the current 10% would be vital input to much other interesting cosmology. There are several programmes which are likely to lead us to this point in the next 10 years.
Marconi, F.; Salas, M.; Yaeger, L.
1976-01-01
A numerical procedure has been developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second order accurate finite difference scheme is used to integrate the three dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool.
Massa, Enrico; Nicolaus, Arnold
2011-04-01
This issue of Metrologia collects papers about the results of an international research project aimed at the determination of the Avogadro constant, NA, by counting the atoms in a silicon crystal highly enriched with the isotope 28Si. Fifty years ago, Egidi [1] thought about realizing an atomic mass standard. In 1965, Bonse and Hart [2] operated the first x-ray interferometer, thus paving the way to the achievement of Egidi's dream, and soon Deslattes et al [3] completed the first counting of the atoms in a natural silicon crystal. The present project, outlined by Zosi [4] in 1983, began in 2004 by combining the experiences and capabilities of the BIPM, INRIM, IRMM, NIST, NPL, NMIA, NMIJ and PTB. The start signal, ratified by a memorandum of understanding, was a contract for the production of a silicon crystal highly enriched with 28Si. The enrichment process was undertaken by the Central Design Bureau of Machine Building in St Petersburg. Subsequently, a polycrystal was grown in the Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences in Nizhny Novgorod and a 28Si boule was grown and purified by the Leibniz-Institut für Kristallzüchtung in Berlin. Isotope enrichment made it possible to apply isotope dilution mass spectroscopy, to determine the Avogadro constant with unprecedented accuracy, and to fulfil Egidi's dream. To convey Egidi's 'fantasy' into practice, two 28Si kilogram prototypes shaped as quasi-perfect spheres were manufactured by the Australian Centre for Precision Optics; their isotopic composition, molar mass, mass, volume, density and lattice parameter were accurately determined and their surfaces were chemically and physically characterized at the atomic scale. The paper by Andreas et al reviews the work carried out; it collates all the findings and illustrates how Avogadro's constant was obtained. Impurity concentration and gradients in the enriched crystal were measured by infrared spectroscopy and taken into
Hyperfine Constants for Low-Lying States in 137Ba+
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Relativistic many-body perturbation calculation is applied to calculate the hyperfine constants for the low-lying states 6S1/2, 6P1/2, 6P3/2, 5D3/2, and 5D5/2 in the alkaline earth ion 137Ba+. The zeroth-order hyperfine constants are calculated with Dirac-Fock wave functions, and the finite basis sets of the Dirac-Fock equation are constructed by B splines. With the finite basis sets, the core polarization and the correlation effect are calculated. The final results for magnetic dipole hyperfine a constants are obtained.
Conjugate Acid-Base Pairs, Free Energy, and the Equilibrium Constant
Beach, Darrell H.
1969-01-01
Describes a method of calculating the equilibrium constant from free energy data. Values of the equilibrium constants of six Bronsted-Lowry reactions calculated by the author's method and by a conventional textbook method are compared. (LC)
International Nuclear Information System (INIS)
Motivated by new energetic constraints and the interest of biomass, the authors report a bibliographical survey of studies concerning the evaluation of the available forest biomass. They comment the geographical and time distribution of the identified and compiled studies. They analyse their different topics. Then, they discuss the various field hypotheses, discuss and comments various resource assessment methodologies. They comment the resource the French forest can be, present a synthesis of the available resource at the regional level according to the different studies. They propose a review of some technical-economical aspects (costs, energy cost, price evolutions, improvement of the wood-energy mobilization). The second part proposes a whole set of volume calculations for different forest types (clusters or plantations of trees, copses, sawmills products), for industry and household consumption. It discusses the available volumes with respect to accessibility, additional available volumes, and possible improvements. The third part analyses, comments and discusses the wood market and wood energetic uses, and the possible supply curves for wood energetic uses by 2016
Marconi, F.; Yaeger, L.
1976-01-01
A numerical procedure was developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second-order accurate finite difference scheme is used to integrate the three-dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine-Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool.
Estimation of Stability Constants of Complex Compounds
Directory of Open Access Journals (Sweden)
Raos, N.
Full Text Available The stability constant of a complex generally depends on the electronic, stereochemical and steric factors, as well as on the chelate effect and interaction of the complex, metal and ligand with water. In the first part of the paper we discuss the Irving-Williams order of stability of bivalent transition metal ion complexes from Mn2+ to Zn2+, along with the HSAB model (hard and soft acids and bases of stability. The second part describes three kinds of models for the estimation of the stability constants of complex compounds. First are those based on molecular mechanics, which were used mainly for the estimation of the enantioselectivity effect, i. e. Gibbs energy differences between MLL and MDL isomers. The second kind of models are mechanistic, that rest on the presumption of linear dependence of measured stability constants of the complexes with the same ligand (stability constants of mono- and bis-complexes, protonation constants, etc.. The third kind of models are heuristic (QSPR, which encompass molecular descriptors calculated by the method of overlapping spheres (OS, as well as topological indices. Among the variety of topological indices, connectivity indices proved best. They were calculated for the ligand and various representations of the coordination compound structure.
Optical properties of fly ash. Volume 2, Final report
Energy Technology Data Exchange (ETDEWEB)
Self, S.A.
1994-12-01
Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executive summary of the whole program followed by the dissertation of Ghosal and Ebert. Volume 2 contains the dissertation of Ebert which covers the measurements of the optical constants of slags, and calculations of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.
Energy Technology Data Exchange (ETDEWEB)
Fujimoto, M.; Nishida, K.; Hiroyasu, H. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering; Tabata, M. [Mazda Motor Corp., Hiroshima (Japan)
1996-06-25
Laser-induced fluorescence from nitrogen dioxide (NO2) as gas fuel tracer was applied to determine mixture stratification in a pancake-type constant-volume combustion chamber using propane and hydrogen fuels. The second-harmonic output of a pulsed Nd: YAG laser was used as a light source for fluorescence excitation. The fluorescence images were corrected by a gated image-intensified CCD camera. The quantitative analysis of fuel concentration was made possible by the application of linearity between fluorescence intensity and NO2 concentration at a low trace level. The stratified mixture (center-rich or center-lean) was concentrically formed in the central region of the chamber by a jet flow from a tangentially oriented port. The concentration difference in the radial direction of the chamber decreased with time from the start of injection. The rate of decrease was faster for hydrogen than for propane. After 300 ms from start of injection, however, the time histories of the concentration difference were nearly constant for both fuels regardless of overall concentration. 10 refs., 16 figs., 1 tab.
RNA structure and scalar coupling constants
Energy Technology Data Exchange (ETDEWEB)
Tinoco, I. Jr.; Cai, Z.; Hines, J.V.; Landry, S.M.; SantaLucia, J. Jr.; Shen, L.X.; Varani, G. [Univ. of California, Berkeley, CA (United States)
1994-12-01
Signs and magnitudes of scalar coupling constants-spin-spin splittings-comprise a very large amount of data that can be used to establish the conformations of RNA molecules. Proton-proton and proton-phosphorus splittings have been used the most, but the availability of {sup 13}C-and {sup 15}N-labeled molecules allow many more coupling constants to be used for determining conformation. We will systematically consider the torsion angles that characterize a nucleotide unit and the coupling constants that depend on the values of these torsion angles. Karplus-type equations have been established relating many three-bond coupling constants to torsion angles. However, one- and two-bond coupling constants can also depend on conformation. Serianni and coworkers measured carbon-proton coupling constants in ribonucleosides and have calculated their values as a function of conformation. The signs of two-bond coupling can be very useful because it is easier to measure a sign than an accurate magnitude.
The interacting and non-constant cosmological constant
International Nuclear Information System (INIS)
We propose a time-varying cosmological constant with a fixed equation of state, which evolves mainly through its interaction with the background during most of the long history of the universe. However, such interaction does not exist in the very early and the late-time universe and produces the acceleration during these eras when it becomes very nearly a constant. It is found that after the initial inflationary phase, the cosmological constant, which we call as lambda parameter, rolls down from a large constant value to another but very small constant value and further dominates the present epoch showing up in the form of the dark energy driving the acceleration. (author)
Adelic Universe and Cosmological Constant
Makhaldiani, Nugzar
2003-01-01
In the quantum adelic field (string) theory models, vacuum energy -- cosmological constant vanish. The other (alternative ?) mechanism is given by supersymmetric theories. Some observations on prime numbers, zeta -- function and fine structure constant are also considered.
Raos, Nenad
2005-01-01
The method of overlapping spheres (OS) was applied to the estimation of stability constants of mono- (log β110) and bis-complexes (log β120) of α-amino acids and their N-alkyl and N,Ndialkyl derivatives with copper(II). The central sphere, with a 0.3 or 0.4 nm radius, was placed at the central (Cu), equatorial (N) or apical (X) position of the coordination polyhedron. The overlapping volume of the central sphere and the van der Waals spheres of neighbouring atoms was calculated and correlated...
Dyes with high dielectric constants
Langhals, Heinz
1988-01-01
The dielectric constants of perylene dyes, perylene-3,4: 9,10-tetracarboxylic bisimides, are reported. With aromatic substituents, dielectric constants up to 110 are obtained. With polymeric dyes, the dielectric constants rise to 260. Mechanisms and applications are discussed.
40 CFR 86.519-90 - Constant volume sampler calibration.
2010-07-01
... in. Hg) Ambient temperature TA °C ( °F) ±0.3 °C (±0.54 °F) Air Temperature into LFE ETI °C ( °F) ±0..., the system verification may be performed using either propane or carbon monoxide. If the CVS and... orifice devices.) (1) Obtain a small cylinder that has been charged with pure propane or carbon...
Theoretical and experimental investigation of methanol combustion under constant volume
Energy Technology Data Exchange (ETDEWEB)
Tatem, P.A.F.
1984-01-01
This work advances the area of zone modeling through the development of a five-zone theoretical model with time-incrementing capabilities to predict the results of burning liquid pool methanol fires in a gastight enclosure. The model consists of a liquid fuel bed, a developed flame above the fuel bed, a plume sitting on top of the flame, the enclosure walls, and an ambient gaseous medium existing between the enclosure walls and flame-plume boundaries. The model assumes chemical equilibrium to determine the energy available from the combusting fuel, and temperature-dependent equilibrium concentrations of the combustion products. Once the available energy has been dictated by the chemical equilibrium, the energy feedback occurring within each defined zone makes possible the prediction of the temperatures (ambient gas, flame, and plume), the mass evaporation rate of the fuel, and the total pressure and oxygen concentration within the enclosure. The physical effects of the oxygen concentration on a confined methanol fire were well established in this work through a comparison of the results from the enclosed model with model results from the same fire in the open.
High Duty Cycle, Extended Operation Constant Volume Combustion Engine Project
National Aeronautics and Space Administration — The Science Mission Directorate is chartered with answering fundamental questions requiring the view from and into space. Its future direction will be moving away...
Constant Volume Combustion Engine for Planetary Ascent Vehicles Project
National Aeronautics and Space Administration — The Mars Sample Return mission is being planned to return samples of Martian rock, regolith, and atmosphere to Earth for scientific analysis. The Martian sample...
Stability constants for silicate adsorbed to ferrihydrite
DEFF Research Database (Denmark)
Hansen, Hans Christian Bruun; Wetche, T.P.; Raulund-Rasmussen, Karsten;
1994-01-01
Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption...... experiments in 0.01 m NaNO3 electrolyte (pH 3-6). The surface equilibrium constants were calculated according to the two-layer model by Dzombak & Morel (1990). Near equilibrium between protons/hydroxyls in solution and the ferrihydrite surface was obtained within minutes while equilibration with silicate...
Bao, Junwei Lucas; Sripa, Pattrawan; Truhlar, Donald G
2016-01-14
Multi-path variational transition state theory (MP-VTST) provides a conformationally complete framework for calculating gas-phase rate constants. For reactions in which the transition state has distinguishable torsional minima (which include most reactions), there are multiple possible reaction paths. In principle MP-VTST includes the contributions from all the reaction paths, and it should explicitly treat the variational and tunneling effects of each path, but in practice one may need to truncate the number of paths included in MP-VTST calculations in order to achieve a balance between computational cost and accuracy. In this work, we present calculations including all paths for two prototype combustion reactions, namely the two hydrogen abstraction reactions from tert-butanol by HO2 radical. For both reactions we included all the reaction paths. Since abstraction at C has 46 paths, it provided a good opportunity to carry out a case study in which we investigated the errors introduced by truncating the number of paths. For the reaction studied, we found that the variational and multidimensional tunneling transmission coefficients are very different for different reaction paths, which provides new evidence that MP-VTST is necessary for treating path-dependent variational effects and multidimensional tunneling. We found that tunneling transmission coefficients can be much larger for higher-energy paths than for lower-energy ones. Interestingly, the simple hypothesis that higher barriers are narrower does not explain this finding in the present case; we found instead that the effect is due to higher-energy barriers having the possibility of tunneling at energies farther below the barrier top. We also show that a previously applied criterion for judging convergence with respect to the number of paths may not be reliable at low temperature. PMID:26658549
Curvature induced running of the cosmological constant
Markkanen, Tommi
2014-01-01
In this work we investigate the renormalization group flow of the cosmological constant $\\Lambda$ induced by the change in space-time curvature in the electroweak vacuum. We calculate the generic magnitude resulting from running in the standard model in a subtraction scheme that respects the Appelquist-Carazzone decoupling theorem. Interestingly, we find in this prescription that for a non-minimal coupling $\\xi\\lesssim 10^4$ the magnitude of the generated contribution remains below the value consistent with observations.
String coupling constant seems to be 1
Yoon, Youngsub
2016-01-01
We present a reasoning that the string coupling constant should be 1 from the assumption that the area spectrum derived from loop quantum gravity must be equal to the area spectrum calculated from "stringy differential geometry." To this end, we will use the loop quantum gravity area spectrum constructions proposed by Brian Kong and us, and stringy differential geometry based on double field theory recently proposed by Imtak Jeon, Kanghoon Lee and Jeong-Hyuck Park.
Comoving suppression mechanism and cosmological constant problem
Shen, Jian Qi
2004-01-01
In this paper, we assume that the observer is fixed in a comoving frame of reference with $g_{00}=\\frac{\\lambda}{\\Lambda}$, where $\\lambda$ and $\\Lambda$ denote the comoving parameter and the cosmological constant, respectively. By using the {\\it comoving suppression mechanism} and {\\it Mach's principle} (the latter of which is used to determine the comoving parameter $\\lambda$), we calculate the vacuum energy density of quantum fluctuation field in the above-mentioned comoving frame of refer...
Pseudoscalar mesons in a finite cubic volume with twisted boundary conditions
Colangelo, Gilberto
2016-01-01
We study the effects of a finite cubic volume with twisted boundary conditions on pseudoscalar mesons. We first apply chiral perturbation theory in the p-regime and calculate the corrections for masses, decay constants, pseudoscalar coupling constants and form factors at next-to-leading order. We show that the Feynman-Hellmann theorem and the relevant Ward-Takahashi identity are satisfied. We then derive asymptotic formulae a la Luscher for twisted boundary conditions. We show that chiral Ward identities for masses and decay constants are satisfied by the asymptotic formulae in finite volume as a consequence of infinite-volume Ward identities. Applying asymptotic formulae in combination with chiral perturbation theory we estimate corrections beyond next-to-leading order for twisted boundary conditions.
Fine Structure Constant: Theme With Variations
Bezerra, V B; Muniz, C R; Tahim, M O; Vieira, H S
2016-01-01
In this paper, we study the spatial variation of the fine structure constant $\\alpha$ due to the presence of a static and spherically symmetric gravitational source. The procedure consists of calculating the solution including the energy eigenvalues of a massive scalar field around that source, considering the weak-field regimen, which yields the gravitational analog of the atomic Bohr levels. From this result, we obtain several values for the effective $\\alpha$ by considering some scenarios of semi-classical and quantum gravities. Constraints on the parameters of the involved theories are calculated from astrophysical observations of the white dwarf emission spectra. Such constraints are compared with those ones obtained in the literature.
Institute of Scientific and Technical Information of China (English)
吴福飞; 董双快; 宫经伟; 陈亮亮; 李东生; 侍克斌
2016-01-01
Powers theory proposes calculation method for the pure volume of cement hydration products, which does not apply to calculate the volume of cementitious materials with mineral admixture. The formula of cementitious materials volume was proposed that based on the basic principles of cement and mineral admixture hydration, and the proposed method of reliability was verified by the results of Powers theoretical model and volume fraction of cement hydration products. On this basis, the factor such as water-cement ratio, the ratio of admixture and types was further researched for the volumes of cementitious materials hydration products. Mixture in test were designed 2 water-cement ratio (0.30 and 0.40, respectively), two content (20% and 60%, respectively) of mineral admixture, and 3 kinds of mineral admixture (lithium slag, fly ash and steel slag, respectively), forming paste that was stirred according with the designed ratio in 5 mL centrifuge tube in a blender and curing to 1, 7, 14, 28, 60 and 90 d in curing room (temperature was (20±1)℃, humidity was not less than 95%), and then testing reaction extent of cement and mineral admixture (such as fly ash, steel slag. lithium slag) according with the chemical bound water and HCl dissolution method. The results showed that hydration extent of lithium slag, fly ash and steel slag at 28d decreased by 46.63%, 69.56% and 74.82% (P<0.05) when mineral admixture content varied from 20% to 60% and water-cement ratio was 0.30. Hydration extent of cement at 28 d was increased by 7.25% when water-cement ratio increased from 0.30 to 0.40. When mineral admixture content varied from 20% to 60%, hydration extent of lithium slag, fly ash and steel slag at 28 d increased by 24.14% 18.56%, 17.61% and 8.84%, 12.21%, and 29.37% (P<0.05), respectively. In contrast, the influence of the mineral admixture content was bigger than water-cement ratio for the hydration extent of composite cementitious materials. In different water-cement ratio
Computing the dielectric constant of liquid water at constant dielectric displacement
Zhang, Chao
2015-01-01
The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement D. The method to constrain the electric displacement is the finite temperature classical variant of the constant-D method developed by Stengel, Spaldin and Vanderbilt (Nat. Phys. 2009, 5: 304). There is also a modification of this scheme imposing fixed values of the macroscopic field E. The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at D = 0 and E = 0 and two from the variation of polarization with finite D and E. It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies however, with constant D calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polar...
Forward recursions and normalizing constant
Guyon, Xavier; Hardouin, Cécile
2009-01-01
Maximum likelihood parameter estimation is frequently replaced by various techniques because of its intractable normalizing constant. In the same way, the literature displays various alternatives for distributions involving such unreachable constants. In this paper, we consider a Gibbs distribution $\\pi $ and present a recurrence formula allowing a recursive calculus of the marginals of $\\pi $ and in the same time its normalizing constant$.$ The numerical performance of this algorithm is eval...
Basic constant of matter world
International Nuclear Information System (INIS)
It was analysed how to gain constant 46 hidden among elementary units of matter world, which is divided into, 1, 2, 4, 8, 16, 8, 4, 2, 1. Here it shows the unity of opposites on philosophy and simple symmetric beauty of mathphysics. The constant specifically shows that scope constant 44 in nuclides layer of matter world and chromosome number of mankind is 23 pairs, which is the highest form of matter motion, the basic cause of existing constant 46 is that matter exists in space-time with 4-dimensions, and it obeys the principle of the most lower energy
Bubble growth constants for liquid hydrogen and liquid helium
International Nuclear Information System (INIS)
Bubble growth constants are calculated for liquid H2 and liquid He at various pressures and liquid superheats for spherically symmetric growth using Scrivens' solution (Chem. Eng. Sci.; 10 (1959)). The constants are shown to be applicable to bubble growth at a heated wall during boiling of cryogenic liquids. (author)
Essential nature of Newton's constant in unimodular gravity
Benedetti, Dario
2016-05-01
We point out that in unimodular gravity Newton's constant is an essential coupling, i.e. it is independent of field redefinitions. We illustrate the consequences of this fact by a calculation in a standard simple approximation, showing that in this case the renormalization group flow of Newton's constant is gauge and parametrization independent.
Graviton mass and cosmological constant: a toy model
Metaxas, Dimitrios
2010-01-01
I consider a simple model where the graviton mass and the cosmological constant depend on a scalar field with appropriate couplings and I calculate the graviton propagator and the induced effective action for the scalar field.
Graviton mass and cosmological constant: a toy model
Metaxas, Dimitrios
2010-01-01
I consider a simple model where the graviton mass and the cosmological constant depend on a scalar field with appropriate couplings and I calculate the graviton propagator and the resulting effective action for the scalar field.
Pion Decay Constant, ZA and Chiral Log from Overlap Fermions
International Nuclear Information System (INIS)
We report our calculation of the pion decay constant fπ, the axial renormalization constant ZA, and the quenched chiral logarithms from the overlap fermions. The calculation is done on a quenched 204 lattice at a=0.148 fm using tree level tadpole improved gauge action. The smallest pion mass we reach is about 280 MeV. The lattice size is about 4 times the Compton wavelength of the lowest mass pion
Fundamental Nature of the Fine-Structure Constant
Sherbon, Michael A.
2014-01-01
Arnold Sommerfeld introduced the fine-structure constant that determines the strength of the electromagnetic interaction. Following Sommerfeld, Wolfgang Pauli left several clues to calculating the fine-structure constant with his research on Johannes Kepler's view of nature and Pythagorean geometry. The Laplace limit of Kepler's equation in classical mechanics, the Bohr-Sommerfeld model of the hydrogen atom and Julian Schwinger's research enable a calculation of the electron magne...
Critical experiments analysis by ABBN-90 constant system
International Nuclear Information System (INIS)
The ABBN-90 is a new version of the well-known Russian group-constant system ABBN. Included constants were calculated based on files of evaluated nuclear data from the BROND-2, ENDF/B-VI, and JENDL-3 libraries. The ABBN-90 is intended for the calculation of different types of nuclear reactors and radiation shielding. Calculations of criticality safety and reactivity accidents are also provided by using this constant set. Validation of the ABBN-90 set was made by using a computerized bank of evaluated critical experiments. This bank includes the results of experiments conducted in Russia and abroad of compact spherical assemblies with different reflectors, fast critical assemblies, and fuel/water-solution criticalities. This report presents the results of the calculational analysis of the whole collection of critical experiments. All calculations were produced with the ABBN-90 group-constant system. Revealed discrepancies between experimental and calculational results and their possible reasons are discussed. The codes and archives INDECS system is also described. This system includes three computerized banks: LEMEX, which consists of evaluated experiments and their calculational results; LSENS, which consists of sensitivity coefficients; and LUND, which consists of group-constant covariance matrices. The INDECS system permits us to estimate the accuracy of neutronics calculations. A discussion of the reliability of such estimations is finally presented. 16 figs
Critical experiments analysis by ABBN-90 constant system
Energy Technology Data Exchange (ETDEWEB)
Tsiboulia, A.; Nikolaev, M.N.; Golubev, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)] [and others
1997-06-01
The ABBN-90 is a new version of the well-known Russian group-constant system ABBN. Included constants were calculated based on files of evaluated nuclear data from the BROND-2, ENDF/B-VI, and JENDL-3 libraries. The ABBN-90 is intended for the calculation of different types of nuclear reactors and radiation shielding. Calculations of criticality safety and reactivity accidents are also provided by using this constant set. Validation of the ABBN-90 set was made by using a computerized bank of evaluated critical experiments. This bank includes the results of experiments conducted in Russia and abroad of compact spherical assemblies with different reflectors, fast critical assemblies, and fuel/water-solution criticalities. This report presents the results of the calculational analysis of the whole collection of critical experiments. All calculations were produced with the ABBN-90 group-constant system. Revealed discrepancies between experimental and calculational results and their possible reasons are discussed. The codes and archives INDECS system is also described. This system includes three computerized banks: LEMEX, which consists of evaluated experiments and their calculational results; LSENS, which consists of sensitivity coefficients; and LUND, which consists of group-constant covariance matrices. The INDECS system permits us to estimate the accuracy of neutronics calculations. A discussion of the reliability of such estimations is finally presented. 16 figs.
Spectrophotometric determination of association constant
DEFF Research Database (Denmark)
Spanget-Larsen, Jens
2016-01-01
Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charg...
The stability of fundamental constants
International Nuclear Information System (INIS)
The tests of the constancy of fundamental constants are tests of the local position invariance and thus of the equivalence principle, at the heart of general relativity. After summarising the links between fundamental constants, gravity, cosmology and metrology, a brief overview of the observational and experimental constraints on their variation is proposed. (authors)
Optical diffraction by inhomogeneous volume objects
Forte, Gustavo; Lencina, Alberto; Tebaldi, Myrian; Bolognini, Nestor
2008-08-01
Electromagnetic waves propagation research in volume media increases considerably in the last years. The study evolved from thick hologram gratings, Bragg and Raman-Nath diffraction regimes up to current research in photonics materials. Usually differential methods are employed to account for the light transmitted for volume media. In our proposal, we develop a simple and versatile integral method to calculate the diffracted field provided the media refractive index has low variations in a wavelength scale. In fact, starting from first principles, we obtain a modified version of the Fresnel propagator of the scalar diffraction theory. Our method is valid for some kind of magnetic, dielectric and absorbent inhomogeneous media. In particular, for TE (TM) fields, we can study media where the permittivity (permeability) gradient is perpendicular to the electric (magnetic) field and its permeability (permittivity) is constant. To validate the approach, we applied it to (in) homogeneous media having well known diffraction properties.
Directory of Open Access Journals (Sweden)
Pieprzyca J.
2015-04-01
Full Text Available A common method used in identification of hydrodynamics phenomena occurring in Continuous Casting (CC device's tundish is to determine the RTD curves of time. These curves allows to determine the way of the liquid steel flowing and mixing in the tundish. These can be identified either as the result of numerical simulation or by the experiments - as the result of researching the physical models. Special problem is to objectify it while conducting physical research. It is necessary to precisely determine the time constants which characterize researched phenomena basing on the data acquired in the measured change of the concentration of the tracer in model liquid's volume. The mathematical description of determined curves is based on the approximate differential equations formulated in the theory of fluid mechanics. Solving these equations to calculate the time constants requires a special software and it is very time-consuming. To improve the process a method was created to calculate the time constants with use of automation elements. It allows to solve problems using algebraic method, which improves interpretation of the research results of physical modeling.
Experimental determination of the effective strong coupling constant
Energy Technology Data Exchange (ETDEWEB)
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2007-07-01
We extract an effective strong coupling constant from low Q{sup 2} data on the Bjorken sum. Using sum rules, we establish its Q{sup 2}-behavior over the complete Q{sup 2}-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Variation of the fine structure constant
Lipovka, Anton A
2016-01-01
In present paper we evaluate the fine structure constant variation which should take place as the Universe is expanded and its curvature is changed adiabatically. This changing of the fine structure constant is attributed to the energy lost by physical system (consist of baryonic component and electromagnetic field) due to expansion of our Universe. Obtained ratio (d alpha)/alpha = 1. 10{-18} (per second) is only five times smaller than actually reported experimental limit on this value. For this reason this variation can probably be measured within a couple of years. To argue the correctness of our approach we calculate the Planck constant as adiabatic invariant of electromagnetic field, from geometry of our Universe in the framework of the pseudo- Riemannian geometry. Finally we discuss the double clock experiment based on Al+ and Hg+ clocks carried out by T. Rosenband et al. (Science 2008). We show that in this particular case there is an error in method and this way the fine structure constant variation c...
Pion decay constants in dense skyrmion matter
Directory of Open Access Journals (Sweden)
Lee H.-J.
2010-10-01
Full Text Available According to the QCD, the hadronic matter can have various phases with matter density and temperature. In general, when there is phase transition in a matter, it is known that a symmetry in the matter changes. In case of the hadronic matter, the chiral symmetry in the matter is expected to be restored when the matter density (or temperature increases. The actual order parameter with respect to the chiral symmetry in the hadronic matter is known as the quark condensate from the QCD, but the pion decay constant, corresponding to the radius of the chiral circle, plays the role of the order parameter in an eﬀective ﬁeld theoretical approach to the QCD. In this paper, by using the skyrmion model which is an eﬀective theory to the QCD, we construct the skyrmion matter as a model of the hadronic matter (nuclear matter and calculate the pion decay constant in the matter. Because of presence of the matter, the pion decay constant is split into the two components, the temporal component and the spatial component. We discuss the phase transition in the skyrmion matter and behavior of the two components of the decay constant for massless pion with density of the skyrmion matter.
PWR refill-reflood analysis with experimental loop and calculation model. Pt. 2
International Nuclear Information System (INIS)
Equations for control volumes varying in the time have been applied. The bottom and length of the bubble and film boiling region in the core are specified by a correlation and time constant based on our measurements. The boiling volume is divided into two parts, saturated water and steam volume. The hydraulic processes are calculated to the average fuel rod, but for the temperatures also the hot rod is calculated. Some parameters have been determined by comparison of measured and calculated results. Sensitivity analyses were made for a PWR, and the hydraulic resistance of the pump (and water stopper evtl. in the loop) was found as the most important factor to ensure a sufficient reflood. (orig.)
Computing the Gromov hyperbolicity constant of a discrete metric space
Ismail, Anas
2012-07-01
Although it was invented by Mikhail Gromov, in 1987, to describe some family of groups[1], the notion of Gromov hyperbolicity has many applications and interpretations in different fields. It has applications in Biology, Networking, Graph Theory, and many other areas of research. The Gromov hyperbolicity constant of several families of graphs and geometric spaces has been determined. However, so far, the only known algorithm for calculating the Gromov hyperbolicity constant of a discrete metric space is the brute force algorithm with running time O (n4) using the four- point condition. In this thesis, we first introduce an approximation algorithm which calculates a O (log n)-approximation of the hyperbolicity constant , based on a layering approach, in time O (n2), where n is the number of points in the metric space. We also calculate the fixed base point hyperbolicity constant r for a fixed point r using a (max; min)matrix multiplication algorithm by Duan in time O (n2:688) [2]. We use this result to present a 2-approximation algorithm for calculating the hyperbolicity constant in time O (n2:688). We also provide an exact algorithm to compute the hyperbolicity constant in time O (n3:688) for a discrete metric space. We then present some partial results we obtained for designing some approximation algorithms to compute the hyperbolicity constant.
Cichy, Krzysztof; Korcyl, Piotr
2016-01-01
Working in a quenched setup with Wilson twisted mass valence fermions, we explore the possibility to compute non-perturbatively the step scaling function using the coordinate (X-space) renormalization scheme. This scheme has the advantage of being on-shell and gauge invariant. The step scaling method allows us to calculate the running of the renormalization constants of quark bilinear operators. We describe here the details of this calculation. The aim of this exploratory study is to identify the feasibility of the X-space scheme when used in small volume simulations required by the step scaling technique. Eventually, we translate our final results to the continuum MSbar scheme and compare against four-loop analytic formulae finding satisfactory agreement.
Electrical installation calculations
Watkins, AJ
2006-01-01
Designed to provide a step by step guide to successful application of the electrical installation calculations required in day to day electrical engineering practice, the Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike.Now in its seventh edition, Volume 1 has been fully updated to meet the requirements of the 2330 Level 2 Certificate in Electrotechnical Technology from City & Guilds, and will also prove a vi
Constant Communities in Complex Networks
Chakraborty, Tanmoy; Ganguly, Niloy; Bhowmick, Sanjukta; Mukherjee, Animesh
2013-01-01
Identifying community structure is a fundamental problem in network analysis. Most community detection algorithms are based on optimizing a combinatorial parameter, for example modularity. This optimization is generally NP-hard, thus merely changing the vertex order can alter their assignments to the community. However, there has been very less study on how vertex ordering influences the results of the community detection algorithms. Here we identify and study the properties of invariant groups of vertices (constant communities) whose assignment to communities are, quite remarkably, not affected by vertex ordering. The percentage of constant communities can vary across different applications and based on empirical results we propose metrics to evaluate these communities. Using constant communities as a pre-processing step, one can significantly reduce the variation of the results. Finally, we present a case study on phoneme network and illustrate that constant communities, quite strikingly, form the core func...
Energy Technology Data Exchange (ETDEWEB)
Gomez T, A. M.; Xolocostli M, V. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Lopez M, R.; Filio L, C. [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico); Royl, P., E-mail: armando.gomez@inin.gob.mx [Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz I, D-76344 Eggenstein-Leopoldshafen (Germany)
2014-10-15
In 2012 was modeled of primary and secondary container of the nuclear power plant of Laguna Verde (NPP-L V) for the CFD Gas-Flow code. These models were used to calculate hydrogen volume concentrations run release the reactor building in case of a severe accident. The results showed that the venting would produce detonation conditions in the venting level (level 33) and flammability at ground level of reload. One of the solutions to avoid reaching critical concentrations (flammable or detonable) inside the reactor building and thus safeguard the contentions is to make a rigid venting. The rigid vent is a pipe connected to the primary container could go to the level 33 of the secondary container and style fireplace climb to the top of the reactor building. The analysis of hydrogen transport inside the vent pipe can be influenced by various environmental criteria and factors vent, so a logical consequence of the 2012 analysis is the analysis of the gases transport within said pipe to define vent ideal conditions. For these evaluations the vent pipe was modeled with a fine mesh of 32 radial interior nodes and a coarse mesh of 4 radial interior nodes. With three-dimensional models were realized calculations that allow observing the influence of heat transfer in the long term, i.e. a complete analysis of exhaust (approx. 700 seconds). However, the most interesting results focus on the first milliseconds, when the H{sub 2} coming from the atmosphere of the primary container faces the air in the vent pipe. These first milliseconds besides allowing evaluating the detonation criteria in great detail in the different tubular sections similarly allow evaluating the pressure wave that occurs in the pipe and that at some point slows to the fluid on the last tubular section and could produce a detonation inside the pipe. Results are presented for venting fixed conditions, showing possible detonations into the pipe. (Author)
Fundamental Constants and Conservation Laws
Roh, Heui-Seol
2001-01-01
This work describes underlying features of the universe such as fundamental constants and cosmological parameters, conservation laws, baryon and lepton asymmetries, etc. in the context of local gauge theories for fundamental forces under the constraint of the flat universe. Conservation laws for fundamental forces are related to gauge theories for fundamental forces, their resulting fundamental constants are quantitatively analyzed, and their possible violations at different energy scales are...
Varying Constants, Gravitation and Cosmology
Directory of Open Access Journals (Sweden)
Jean-Philippe Uzan
2011-03-01
Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
From the Rydberg constant to the fundamental constants metrology
International Nuclear Information System (INIS)
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
de Cesare, Marco; Sakellariadou, Mairi
2016-01-01
We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
de Cesare, Marco; Lizzi, Fedele; Sakellariadou, Mairi
2016-09-01
We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Astuti, Valerio; Christodoulou, Marios; Rovelli, Carlo
2016-01-01
Building on a technical result by Brunnemann and Rideout on the spectrum of the Volume operator in Loop Quantum Gravity, we show that the dimension of the space of the quadrivalent states --with finite-volume individual nodes-- describing a region with total volume smaller than $V$, has \\emph{finite} dimension, bounded by $V \\log V$. This allows us to introduce the notion of "volume entropy": the von Neumann entropy associated to the measurement of volume.
How fundamental are fundamental constants?
Duff, M. J.
2015-01-01
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, ?. For example, the standard model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers or scales? they use to measure them. Dimensional constants, on the other hand, such as ?, c, G, e and k ?, are merely human constructs whose number and values differ from one choice of units to the next. In this sense, only dimensionless constants are 'fundamental'. Similarly, the possible time variation of dimensionless fundamental 'constants' of nature is operationally well defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as ? or ? on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might disagree depending on their apparatus. All these confusions disappear if one asks only unit-independent questions. We provide a selection of opposing opinions in the literature and respond accordingly.
How fundamental are fundamental constants?
Duff, M J
2014-01-01
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, alpha. For example, the Standard Model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers, scales... they use to measure them. Dimensional constants, on the other hand, such as h, c, G, e, k..., are merely human constructs whose number and values differ from one choice of units to the next. In this sense only dimensionless constants are "fundamental". Similarly, the possible time variation of dimensionless fundamental "constants" of nature is operationally well-defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might...
The 1% concordance Hubble constant
International Nuclear Information System (INIS)
The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s–1 Mpc–1. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H 0/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.
Calculation and Analysis of Lumped Parameter of Volume Conduction Model%体导电能量传递模型集总参数的计算与分析
Institute of Scientific and Technical Information of China (English)
刘海龙; 唐治德; 谢小慧; 陈小梅
2012-01-01
研究生物医学体内植入器件能量供应优化方法,为了优化体导电系统效能,利用皮肤电特性高效地向体内植入器件提高能量.提出体导电能量传递系统体外采用圆形柱体阵列电极,将皮肤电极单元等效为多导体系统,建立了流经各电极的电流与电压的导纳矩阵关系,并用欧姆定律与电磁场原理相结合的方法计算出皮肤电极单元的集总参数.通过比较集总参数,得到圆形柱体阵列电极较圆形柱体电极具有更优的阻抗分配,能够提高体导电电流传递效率.利用有限元软件仿真了圆形柱体阵列电极皮肤单元的电流传递,证明效率能达50％以上.%In order to optimize Volume Conduction system, we used the electrical characteristics of skin to transfer energy to the implanted device efficiently, treated the skin-electrodes of volume conductive as multi-conductor sys-tem , and established the admittance matrix to show the relationship between voltage and current. Ohm's law and elec-tromagnetic field theory were used to calculate the lumped parameter of skin-electrodes unit. Through comparing cir-cular cylinder electrode with circular cylinder arrenging-electrodes' lumped parameter, it can be concluded that cir-cular cylinder arranging-electrodes has better impedance distribution, higher energy transfer efficiency. Finally, fi-nite element software FEMlab3.3 was used to simulate the efficiency of circular cylinder array electrode-skin unit, and it can reach above 50%.
Learning Read-constant Polynomials of Constant Degree modulo Composites
DEFF Research Database (Denmark)
Chattopadhyay, Arkadev; Gavaldá, Richard; Hansen, Kristoffer Arnsfelt;
2011-01-01
known to be learnable in any reasonable learning model. In this paper, we provide a deterministic polynomial time algorithm for learning Boolean functions represented by polynomials of constant degree over arbitrary finite rings from membership queries, with the additional constraint that each variable...
Energy Technology Data Exchange (ETDEWEB)
Nez, F
2005-06-15
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Explosive helium burning at constant pressures
Hashimoto, M.-A.; Hanawa, T.; Sugimoto, D.
The results of numerical calculations of nucleosynthesis under adiabatic conditions, i.e., when the only heat exchange with the external regions takes place through neutrinos, are reported. Attention is focused on explosive burning associated with shell flashes, assuming that nuclear energy is deposited in a mass element, followed by expansion and density decrease. Consideration is given to three cases, the shell flash near the surface of a degenerate star, to nuclear burning concentrated in a small region of a star, and to the heat energy being deposited in intermediate layers. A reaction network of 181 nuclear species was constructed and the thermodynamic evolution was calculated assuming constant pressure and adiabatic conditions. The final products of the reactions of H-1 to Cu-62 were projected to by O-16, Mg-24, Si-28, S-32, Ca-40, Ti-44, Cr-48, and Fe-52.
PREFACE: Fundamental Constants in Physics and Metrology
Klose, Volkmar; Kramer, Bernhard
1986-01-01
This volume contains the papers presented at the 70th PTB Seminar which, the second on the subject "Fundamental Constants in Physics and Metrology", was held at the Physikalisch-Technische Bundesanstalt in Braunschweig from October 21 to 22, 1985. About 100 participants from the universities and various research institutes of the Federal Republic of Germany participated in the meeting. Besides a number of review lectures on various broader subjects there was a poster session which contained a variety of topical contributed papers ranging from the theory of the quantum Hall effect to reports on the status of the metrological experiments at the PTB. In addition, the participants were also offered the possibility to visit the PTB laboratories during the course of the seminar. During the preparation of the meeting we noticed that even most of the general subjects which were going to be discussed in the lectures are of great importance in connection with metrological experiments and should be made accessible to the scientific community. This eventually resulted in the idea of the publication of the papers in a regular journal. We are grateful to the editor of Metrologia for providing this opportunity. We have included quite a number of papers from basic physical research. For example, certain aspects of high-energy physics and quantum optics, as well as the many-faceted role of Sommerfeld's fine-structure constant, are covered. We think that questions such as "What are the intrinsic fundamental parameters of nature?" or "What are we doing when we perform an experiment?" can shed new light on the art of metrology, and do, potentially, lead to new ideas. This appears to be especially necessary when we notice the increasing importance of the role of the fundamental constants and macroscopic quantum effects for the definition and the realization of the physical units. In some cases we have reached a point where the limitations of our knowledge of a fundamental constant and
Institute of Scientific and Technical Information of China (English)
林加兴
2011-01-01
针对山美水库库区污染物问题，对库区2011年污染物入库量进行初步计算得出流域污染物入库量及主要污染源，建议采取工程治理措施和非工程措施相结合的方法削减入库污染负荷，供山美水库流域水源地水污染防治实施参考。并能通过实施水生态系统保护与修复技术工程的建设，解决目前危害水源地安全的重大问题，推动山美水库水源地保护工作的全面开展。%Aimed at the pollutant discharge status of Shanmei Reservoir, the pollutant volume into the reservoir area in 2011 is calculated primarily, and some problems about the basin pollution are put forward, then the suggestions are proposed that the methods combining the engineering measures with non-engineering measures are used for reducing the pollution load into the reservoir, which could provide references for the reservoir＇s water resource pollution controlling. At the same time, through carrying out the aquatic ecosystem protection and remedying project, the serious problems of harming the security of water sources could be solved, and the water source protection job for Shamnei Reservoir could be promoted comprehensively.
International Nuclear Information System (INIS)
To gain a better understanding of the risk significance of low power and shutdown modes of operation, the Office of Nuclear Regulatory Research at the NRC established programs to investigate the likelihood and severity of postulated accidents that could occur during low power and shutdown (LP ampersand S) modes of operation at commercial nuclear power plants. To investigate the likelihood of severe core damage accidents during off power conditions, probabilistic risk assessments (PRAs) were performed for two nuclear plants: Unit 1 of the Grand Gulf Nuclear Station, which is a BWR-6 Mark III boiling water reactor (BWR), and Unit 1 of the Surry Power Station, which is a three-loop, subatmospheric, pressurized water reactor (PWR). The analysis of the BWR was conducted at Sandia National Laboratories while the analysis of the PWR was performed at Brookhaven National Laboratory. This multi-volume report presents and discusses the results of the BWR analysis. The subject of this part presents the deterministic code calculations, performed with the MELCOR code, that were used to support the development and quantification of the PRA models. The background for the work documented in this report is summarized, including how deterministic codes are used in PRAS, why the MELCOR code is used, what the capabilities and features of MELCOR are, and how the code has been used by others in the past. Brief descriptions of the Grand Gulf plant and its configuration during LP ampersand S operation and of the MELCOR input model developed for the Grand Gulf plant in its LP ampersand S configuration are given
Energy Technology Data Exchange (ETDEWEB)
Kmetyk, L.N.; Brown, T.D. [Sandia National Labs., Albuquerque, NM (United States)
1995-03-01
To gain a better understanding of the risk significance of low power and shutdown modes of operation, the Office of Nuclear Regulatory Research at the NRC established programs to investigate the likelihood and severity of postulated accidents that could occur during low power and shutdown (LP&S) modes of operation at commercial nuclear power plants. To investigate the likelihood of severe core damage accidents during off power conditions, probabilistic risk assessments (PRAs) were performed for two nuclear plants: Unit 1 of the Grand Gulf Nuclear Station, which is a BWR-6 Mark III boiling water reactor (BWR), and Unit 1 of the Surry Power Station, which is a three-loop, subatmospheric, pressurized water reactor (PWR). The analysis of the BWR was conducted at Sandia National Laboratories while the analysis of the PWR was performed at Brookhaven National Laboratory. This multi-volume report presents and discusses the results of the BWR analysis. The subject of this part presents the deterministic code calculations, performed with the MELCOR code, that were used to support the development and quantification of the PRA models. The background for the work documented in this report is summarized, including how deterministic codes are used in PRAS, why the MELCOR code is used, what the capabilities and features of MELCOR are, and how the code has been used by others in the past. Brief descriptions of the Grand Gulf plant and its configuration during LP&S operation and of the MELCOR input model developed for the Grand Gulf plant in its LP&S configuration are given.
Dlubek, G; Shaikh, M Q; Krause-Rehberg, R; Paluch, M
2007-01-14
The microstructure of the free volume and its temperature dependence in polymethylphenylsiloxane (PMPS) have been examined using positron annihilation lifetime spectroscopy (PALS) and pressure-volume-temperature experiments. The hole-free volume fraction h and the specific hole-free and occupied volumes, Vf=hV and Vocc=(1-h)V, were estimated employing the Simha-Somcynsky (SS) lattice-hole theory. From the PALS spectra analyzed with the new routine LT9.0 the hole size distribution, its mean, , and mean dispersion, sigmah, were calculated. A comparison of with V and Vf delivered a constant specific hole number Nh'. Using a fluctuation approach the temperature dependency of the volume of the smallest representative freely fluctuating subsystem, , is estimated to vary from approximately 8.5 nm3 at Tg to approximately 3 nm3 at T/Tg>or=1.15. Unlike other polymers, the segmental relaxation from dielectric spectroscopy of PMPS follows the Cohen-Turnbull free volume theory almost perfectly in the temperature and pressure ranges between 243 and 279 K and 0 and approximately 100 MPa. This behavior correlates with the small mass of the SS lattice mer which indicates the high flexibility of the PMPS chain. Above 293 K and approximately 150 MPa, the free volume prediction gives relaxation times that are too small, which indicates that effects of thermal energy must be included in the analysis. To quantify the degree to which volume and thermal energy govern the structural dynamics the ratio of the activation enthalpies, Ei=R[(d ln taudT1)]i (tau-relaxation time of alpha relaxation), at constant volume V and constant pressure P, EV/EP, is frequently determined. The authors present arguments for necessity to substitute EV with EVf, the activation enthalpy at constant (hole) free volume, and show that EVf/EP changes as expected: increasing with increasing free volume, i.e., with increasing temperature and decreasing pressure. EVf/EP (=0.04-0.1) exhibits remarkably smaller values
Directory of Open Access Journals (Sweden)
Francisco Mauad Filho
2003-01-01
Full Text Available OBJETIVO: avaliar o volume uterino de mulheres entre 10 e 40 anos, verificando-se se o volume uterino de adolescentes é menor que o volume uterino de mulheres entre 20 e 40 anos. Procuram-se enfatizar as diferenças entre o volume uterino de adolescentes e mulheres adultas correlacionando-as com a imaturidade do trato genital de adolescentes para a gravidez e o parto. MÉTODOS: estudo transversal, no qual 828 pacientes entre 10 e 40 anos foram divididas em dois grupos e avaliadas por meio da ultra-sonografia transabdominal para aferição do volume uterino. O primeiro grupo (Ad foi formado por 477 (57,7% adolescentes e o segundo grupo (Ma por 351 (42,3% mulheres adultas entre 20 e 40 anos. No grupo Ad, os exames ultra-sonográficos foram realizados por um único observador e no grupo Ma, por um grupo de médicos que seguiram a mesma metodologia utilizada no grupo Ad. Os aparelhos ultra-sonográficos utilizados foram Image Point HX (Hewlett Packard e Hitachi 525, com transdutor convexo multifreqüencial. O cálculo do volume uterino foi obtido pelos diâmetros longitudinal (DL, ântero-posterior (DAP e transverso (DT, multiplicados pela constante 0,45. RESULTADOS: o volume uterino de adolescentes entre 10 e 17 anos foi menor que o volume uterino de mulheres entre 20 e 40 anos (p0,05. CONCLUSÃO: o volume uterino de adolescentes com menos de 18 anos ou primíparas é menor que o volume uterino de mulheres entre 20 e 40 anos. Entretanto, adolescentes com 18 anos ou mais, ou secundíparas, têm volume uterino similar ao volume uterino de mulheres entre 20 e 40 anos.PURPOSE: to evaluate the uterine volume in women between 10 and 40 years in order to observe if the uterine volume in adolescents is smaller than the uterine volume in women between 20 and 40 years. We intend to emphasize the differences between the uterine volume of adolescents and that of adult women and to correlate with the immaturity of the genital tract of adolescents regarding
On constant elasticities of demand
Andrés Vázquez
1998-01-01
While the Slutsky matrix and duality theory have been used to establish that constant elasticity demand functions imply unitary income elasticities, zero cross price elasticities and own price elasticities equal to minus one, this note shows that these results can also be straightforwardly derived from the simple assumption that demand functions satisfy the budget constraint with strict equality.
Constant Proportion Debt Obligations (CPDOs)
DEFF Research Database (Denmark)
Cont, Rama; Jessen, Cathrine
2012-01-01
Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from the...
Exponential Decay of Expansive Constants
Sun, Peng
2011-01-01
A map $f$ on a compact metric space is expansive if and only if $f^n$ is expansive. We study the exponential rate of decay of the expansive constant of $f^n$. A major result is that this rate times box dimension bounds topological entropy.
The spectroscopic constants and anharmonic force field of AgSH: An ab initio study.
Zhao, Yanliang; Wang, Meishan; Yang, Chuanlu; Ma, Xiaoguang; Zhu, Ziliang
2016-07-01
The equilibrium structure, spectroscopy constants, and anharmonic force field of silver hydrosulfide (AgSH) have been calculated at B3P86, B3PW91 and MP2 methods employing two basis sets, TZP and QZP, respectively. The calculated geometries, ground state rotational constants, harmonic vibrational wave numbers, and quartic and sextic centrifugal distortion constants are compared with the available experimental and theoretical data. The equilibrium rotational constants, fundamental frequencies, anharmonic constants, and vibration-rotation interaction constants, Coriolis coupling constants, cubic and quartic force constants are predicted. The calculated results show that the MP2/TZP results are in good agreement with experiment observation and are also an advisable choice to study the anharmonic force field of AgSH. PMID:27085293
The 1% concordance Hubble constant
Energy Technology Data Exchange (ETDEWEB)
Bennett, C. L.; Larson, D.; Weiland, J. L. [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Hinshaw, G., E-mail: cbennett@jhu.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)
2014-10-20
The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s{sup –1} Mpc{sup –1}. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H {sub 0}/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.
WHY IS THE SOLAR CONSTANT NOT A CONSTANT?
International Nuclear Information System (INIS)
In order to probe the mechanism of variations of the solar constant on the inter-solar-cycle scale, the total solar irradiance (TSI; the so-called solar constant) in the time interval of 1978 November 7 to 2010 September 20 is decomposed into three components through empirical mode decomposition and time-frequency analyses. The first component is the rotation signal, counting up to 42.31% of the total variation of TSI, which is understood to be mainly caused by large magnetic structures, including sunspot groups. The second is an annual-variation signal, counting up to 15.17% of the total variation, the origin of which is not known at this point in time. Finally, the third is the inter-solar-cycle signal, counting up to 42.52%, which is inferred to be caused by the network magnetic elements in quiet regions, whose magnetic flux ranges from (4.27-38.01) × 1019 Mx.
Production in constant evolution; Produccion en constante evolucion
Energy Technology Data Exchange (ETDEWEB)
Lozano, T.
2009-07-01
The Cofrentes Nuclear Power Plant now has 25 years of operation behind it: a quarter century adding value and demonstrating the reasons why it is one of the most important energy producing facilities in the Spanish power market. Particularly noteworthy is the enterprising spirit of the plant, which has strived to continuously improve with the large number of modernization projects that it has undertaken over the past 25 years. The plant has constantly evolved thanks to the amount of investments made to improve safety and reliability and the perseverance to stay technologically up to date. Efficiency, training and teamwork have been key to the success of the plant over these 25 years of constant change and progress. (Author)
Lattice constant in diluted magnetic semiconductors (Ga,Mn)As
J. Masek; Kudrnovsky, J.; Maca, F.
2003-01-01
We use the density-functional calculations to investigate the compositional dependence of the lattice constant of (Ga,Mn)As containing various native defects. The lattice constant of perfect mixed crystals does not depend much on the concentration of Mn. The lattice parameter increases if some Mn atoms occupy interstitial positions. The same happens if As antisite defects are present. A quantitative agreement with the observed compositional dependence is obtained for materials close to a comp...
Fundamental Physics and the Fine-Structure Constant
Sherbon, Michael A.
2016-01-01
From the exponential function of Euler’s equation to the geometry of a fundamental form, a calculation of the fine-structure constant and its relationship to the proton electron mass ratio is given. Equations are found for the fundamental constants of the four forces of nature: electromagnetism, the weak force, the strong force and the force of gravitation. Symmetry principles are then associated with traditional physical measures.
A new version of the unified constant system package
International Nuclear Information System (INIS)
A unified constant retrieval system called OKS has been developed for convenient access to the constant systems ARAMAKO-2F, ARAMAKO-G, DENSTY, TERMAC and others, in calculating radiation transport, value functions and various functionals. Since the system was first developed in 1980 both its language and its functional contents have been improved and added to. In this paper the input language and performance of the new version are described. (author)
One-group constant libraries for nuclear equilibrium state
Energy Technology Data Exchange (ETDEWEB)
Mizutani, Akihiko; Sekimoto, Hiroshi [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors
1997-03-01
One-group constant libraries for the nuclear equilibrium state were generated for both liquid sodium cooled MOX fuel type fast reactor and PWR type thermal reactor with Equilibrium Cell Iterative Calculation System (ECICS) using JENDL-3.2, -3, -2 and ENDF/B-VI nuclear data libraries. ECICS produced one-group constant sets for 129 heavy metal nuclides and 1238 fission products. (author)
An N-tropic Solution to the Cosmological Constant Problem
Sheikh-Jabbari, M M
2008-01-01
Based on the assertion that the cosmological constant problem is essentially a quantum gravity problem, the framework which addresses the cosmological constant problem should also bear a picture for the ``quantum space-time''. In this talk in an attempt to address the cosmological constant problem I suggest to start with noncommutative fuzzy spheres as the toy model for the quantum space-time. In this setting, we show that the cosmological constant problem may be resolved due to the noncommutativity and ``fuzziness'' of the space and the fact that the smallest volume which could be measured in the a quantum space-time is much larger than the naively expected Planckian size. This talk is based on Ref.[1] which has appeared on the arXiv as hep-th/0605110.
Proceedings of the specialists' meeting on reactor group constants
International Nuclear Information System (INIS)
This report is the Proceedings of the Specialists' Meeting on Reactor Group Constants. The meeting was held on February 22-23, 2001 at Tokai Research Establishment of Japan Atomic Energy Research Institute with the participation of 59 specialists. The evaluation work for JENDL-3.3 is going on for the publication in a short time. The processing JENDL-3.3 file to make reactor group constants is needed when it is used in application fields. In the meeting, the present status of the reactor group constants was reviewed and the issues relating to them were discussed in such fields as thermal reactor, criticality safety, fast reactor, high energy region, burn-up calculation and radiation shielding. At the final session in the meeting, standardization of reactor group constants was discussed and the need of the reference group constants was confirmed by the participants. The 11 of the presented papers are indexed individually. (J.P.N.)
Energy Technology Data Exchange (ETDEWEB)
Abdollahi, Arash, E-mail: arash_abdollahi60@yahoo.com [Department of Physics, Faculty of Science, Urmia Branch, Islamic Azad University, Urmia (Iran, Islamic Republic of)
2013-02-01
Ab initio calculations for the thermal properties of ZrC and ZrN have been performed by using the projector augmented-wave (PAW) method within the generalized gradient approximation (GGA). Pressure-temperature-dependent thermodynamic properties including the bulk modulus, thermal expansion, thermal expansion coefficient, heat capacity at constant volume and constant pressure were calculated using three different models based on the quasi-harmonic approximation (QHA): the Debye-Slater model, Debye-Grueneisen model and full quasi-harmonic model (that requires the phonon density of states at each calculated volume). Also the empirical energy corrections are applied to the results of three models. The calculated values are in good agreement with experimental results. It is found that the full quasi-harmonic model provides more accurate estimates in comparison with the other models.
International Nuclear Information System (INIS)
Ab initio calculations for the thermal properties of ZrC and ZrN have been performed by using the projector augmented-wave (PAW) method within the generalized gradient approximation (GGA). Pressure-temperature-dependent thermodynamic properties including the bulk modulus, thermal expansion, thermal expansion coefficient, heat capacity at constant volume and constant pressure were calculated using three different models based on the quasi-harmonic approximation (QHA): the Debye-Slater model, Debye-Grüneisen model and full quasi-harmonic model (that requires the phonon density of states at each calculated volume). Also the empirical energy corrections are applied to the results of three models. The calculated values are in good agreement with experimental results. It is found that the full quasi-harmonic model provides more accurate estimates in comparison with the other models.
Maris, P; Tandy, P C
1998-01-01
Independent of assumptions about the form of the quark-antiquark scattering kernel we derive the explicit relation between the pion Bethe-Salpeter amplitude, Gamma_pi, and the quark propagator in the chiral limit; Gamma_pi necessarily involves a non-negligible gamma_5 gamma.P term (P is the pion four-momentum). We also obtain exact expressions for the pion decay constant, f_pi, and mass, both of which depend on Gamma_pi; and demonstrate the equivalence between f_pi and the pion Bethe-Salpeter normalisation constant in the chiral limit. We stress the importance of preserving the axial-vector Ward-Takahashi identity in any study of the pion itself, and in any study whose goal is a unified understanding of the properties of the pion and other hadronic bound states.
Wormholes and the cosmological constant
International Nuclear Information System (INIS)
We review Coleman's wormhole mechanism for the vanishing of the cosmological constant. We show that in a minisuperspace model wormhole-connected universes dominate the path integral. We also provide evidence that the euclidean path integral over geometries with spherical topology is unstable with respect to formation of infinitely many wormhole-connected 4-spheres. Consistency is restored by summing over all topologies, which leads to Coleman's result. Coleman's argument for determination of other parameters is reviewed and applied to the mass of the pion. A discouraging result is found that the pion mass is driven to zero. We also consider qualitatively the implications of the wormhole theory for cosmology. We argue that a small number of universes containing matter and energy may exist in contact with infinitely many cold and empty universes. Contact with the cold universes insures that the cosmological constant in the warm ones is zero. (orig.)
Three pion nucleon coupling constants
Arriola, E Ruiz; Perez, R Navarro
2016-01-01
There exist four pion nucleon coupling constants, $f_{\\pi^0, pp}$, $-f_{\\pi^0, nn}$, $f_{\\pi^+, pn} /\\sqrt{2}$ and $ f_{\\pi^-, np} /\\sqrt{2}$ which coincide when up and down quark masses are identical and the electron charge is zero. While there is no reason why the pion-nucleon-nucleon coupling constants should be identical in the real world, one expects that the small differences might be pinned down from a sufficiently large number of independent and mutually consistent data. Our discussion provides a rationale for our recent determination $$f_p^2 = 0.0759(4) \\, , \\quad f_{0}^2 = 0.079(1) \\,, \\quad f_{c}^2 = 0.0763(6) \\, , $$ based on a partial wave analysis of the $3\\sigma$ self-consistent nucleon-nucleon Granada-2013 database comprising 6713 published data in the period 1950-2013.
Quaternions as astrometric plate constants
Jefferys, William H.
1987-01-01
A new method for solving problems in relative astrometry is proposed. In it, the relationship between the measured quantities and the components of the position vector of a star is modeled using quaternions, in effect replacing the plate constants of a standard four-plate-constant solution with the four components of a quaternion. The method allows a direct solution for the position vectors of the stars, and hence for the equatorial coordinates. Distortions, magnitude, and color effects are readily incorporated into the formalism, and the method is directly applicable to overlapping-plate problems. The advantages of the method include the simplicity of the resulting equations, their freedom from singularities, and the fact that trigonometric functions and tangential point transformations are not needed to model the plate material. A global solution over the entire sky is possible.
Ostwald ripening in a system with a high volume fraction of coarsening phase
Hardy, S. C.; Voorhees, P. W.
1988-01-01
The coarsening of Sn-rich and Pb-rich solid phases in contact with eutectic liquid in the volume fraction solid range above approximately 0.6, where the development of a solid skeletal structure inhibits sedimentation, is investigated. Particle intercept distributions are shown to be time independent when scaled by the average intercept. It is noted that the coarsening rate constants obtained exceed the values calculated from theory by factors ranging from about 2 to 5.
Henry's law constants of polyols
Compernolle, S.; J.-F. Müller
2014-01-01
Henry's law constants (HLC) are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. While deriving HLC and depending on the case, also infinite dilution activity coefficients (IDACs), solid state vapour pressures or activity coefficient ratios are obtained as intermediate results. An error analysis on the intermediate quantities and the obtained HLC is included....
Henry's law constants of polyols
Compernolle, S.; J.-F. Müller
2014-01-01
Henry's law constants (HLC) are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. Depending on the case, infinite dilution activity coefficients (IDACs), solid state pressures or activity coefficient ratios are obtained as intermediary results. For most compounds, these are the first values reported, while others compare favourably with literature data in most ...
Planck's constant measurement for dummies
Damyanov, Desislav S; Ilieva, Simona I; Gourev, Vassil N; Yordanov, Vasil G; Mishonov, Todor M
2015-01-01
A simple experimental setup for measuring the Planck's constant, using Landauer quantization of the conductance of touching gold wires, is described. It consists of two gold wires with thickness of 500 micron and 1.5cm length, and a fast operational amplifier. The setup costs less than \\$30 and can be realized in every teaching laboratory in 10 days. The usage of oscilloscope is required.
First-Principles Calculations of Elastic and Thermal Properties of Molybdenum Disilicide
Institute of Scientific and Technical Information of China (English)
ZHU Zun-Lue; FU Hong-Zhi; SUN Jin-Feng; LIU Yu-Fang; SHI De-Heng; XU Guo-Liang
2009-01-01
The first-principles plane-wave pseudopotential method using the generalized gradient approximation within the framework of density functional theory is applied to anaylse the equilibrium lattice parameters,six independent elastic constants,bulk moduli,thermal expansions and heat capacities of MoSi2.The quasi-harmonic Debye model,using a set of total energy versus cell volume obtained with the plane-wave pseudopotential method,is applied to the study of the elastic properties,thermodynamic properties and vibrational effects.The calculated zero pressure elastic constants are in overall good agreement with the experimental data.The calculated heat capacities and the thermal expansions agree well with the observed values under ambient conditions and those calculated by others.The results show that the temperature has hardly any effect under high pressure.
Neutron Scattering and Elastic Constants
International Nuclear Information System (INIS)
Elastic constants of crystals obtained from neutron scattering techniques at frequencies, ω, of the order of 1012 cps, are frequently compared with those obtained with ultrasonic techniques for which ω 10 cps. If the normal modes of vibration of the crystal did not interact with each other or with other excitations in the crystal, these elastic constants would be identical. In a real crystal, however, interactions exist, and these lead to different behaviour, depending on whether the elastic wave propagates in a collision-free, ωτ >> 1, mode or a collision-dominated ωτ 3 have demonstrated this difference. In piezoelectric crystals τ is related to the time required for the electric polarization to follow the elastic wave. At frequencies so high that the electric polarization cannot follow the elastic wave, experiments on DKDP have shown that the elastic constants do not exhibit the anormaly present at low frequencies. Similar behaviour is expected to occur near many phase transitions which show anomalous elastic behaviour. Analogous, but probably smaller, effects occur through the interactions of elastic waves with conduction electrons in metals and with the spins in magnetic materials. (author)
Cosmology with New Astrophysical Constants
Alfonso-Faus, Antonio
2008-01-01
It is shown that Einstein field equations give two solutions for cosmology. The first one is the standard well known representative of the present status of cosmology. We identify it with the local point of view of a flat Universe with the values for the cosmological omega parameters (k = 0, lambda = 2/3, m = 1/3). The second one is a new one that we identify with a cosmic point of view, as given by free photons, neutrinos, tachyons and gravity quanta. We apply a wave to particle technique to find the matter propagation equation. Then we prove that all gravitational radii are constant, regardless of the possible time variations of the physical properties like the speed of light c, the gravitational constant G or the mass m of fundamental particles. We find two cosmological constants, c^3 /G and mc, with the condition that the field equations be derived from the action principle. With this result, and the integration of the Bianchi identity, we prove the existence of the two solutions for cosmology. We then va...
Harg, Erik
2005-01-01
Implementation of automated volume-to-volume registration applications for three separate registration steps desired in enhancing neurosurgical navigation is considered. Prototype implementations for MRI-to-MRI registration, MRI-to-US registration and US-to-US registration have been made using registration methods available in the Insight Toolkit, with variants of the Mutual Information similarity metric. The obtained results indicate that automatic volume-to-volume registration using Normali...
Computational study on Kerr constants of neutral and ionized gases
Sato, M.; Kumada, A.; Hidaka, K.
2015-08-01
In order to quantitatively examine the measurement capability of Poisson's field using electro-optic Kerr-effect (EOKE), Kerr constants of neutral molecules and ions are examined by means of first principle calculations. We have systematically computed Kerr constants of neutral molecules and ions of several molecular symmetry groups, with consistent theory level and basis sets. Computed Kerr constants of neutral molecules (N2, CO2, SF6, and CF3I) ranging across two orders of magnitudes are within 50% error of the experimental values, which are comparable to the scattering between experimental values itself. The results show that SF6 has smaller Kerr constant due to its high molecular symmetry compared to those of N2 and CO2. In contrast, CF3I has large Kerr constant due to its permanent dipole. Computed Kerr constants for anions are larger by two orders of magnitude than those of neutral molecules, probably due to the shielding effect. For cations, the opposite holds true; however, due to anisotropic polarizability, computed Kerr constants for some cations are comparable to neutral molecules, while others show smaller values. The ratio of Kerr constants of ions to those of neutral molecules are at most 102; EOKE is valid for measuring electric field in weakly ionized gas whose ionization degree is smaller than 10-3.