Collett, David
2002-01-01
INTRODUCTION Some Examples The Scope of this Book Use of Statistical Software STATISTICAL INFERENCE FOR BINARY DATA The Binomial Distribution Inference about the Success Probability Comparison of Two Proportions Comparison of Two or More Proportions MODELS FOR BINARY AND BINOMIAL DATA Statistical Modelling Linear Models Methods of Estimation Fitting Linear Models to Binomial Data Models for Binomial Response Data The Linear Logistic Model Fitting the Linear Logistic Model to Binomial Data Goodness of Fit of a Linear Logistic Model Comparing Linear Logistic Models Linear Trend in Proportions Comparing Stimulus-Response Relationships Non-Convergence and Overfitting Some other Goodness of Fit Statistics Strategy for Model Selection Predicting a Binary Response Probability BIOASSAY AND SOME OTHER APPLICATIONS The Tolerance Distribution Estimating an Effective Dose Relative Potency Natural Response Non-Linear Logistic Regression Models Applications of the Complementary Log-Log Model MODEL CHECKING Definition of Re...
Mesoscopic model for binary fluids
Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.
2017-10-01
We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.
Misclassification in binary choice models
Czech Academy of Sciences Publication Activity Database
Meyer, B. D.; Mittag, Nikolas
2017-01-01
Roč. 200, č. 2 (2017), s. 295-311 ISSN 0304-4076 R&D Projects: GA ČR(CZ) GJ16-07603Y Institutional support: Progres-Q24 Keywords : measurement error * binary choice models * program take-up Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 1.633, year: 2016
Misclassification in binary choice models
Czech Academy of Sciences Publication Activity Database
Meyer, B. D.; Mittag, Nikolas
2017-01-01
Roč. 200, č. 2 (2017), s. 295-311 ISSN 0304-4076 Institutional support: RVO:67985998 Keywords : measurement error * binary choice models * program take-up Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 1.633, year: 2016
A simple model for binary star evolution
International Nuclear Information System (INIS)
Whyte, C.A.; Eggleton, P.P.
1985-01-01
A simple model for calculating the evolution of binary stars is presented. Detailed stellar evolution calculations of stars undergoing mass and energy transfer at various rates are reported and used to identify the dominant physical processes which determine the type of evolution. These detailed calculations are used to calibrate the simple model and a comparison of calculations using the detailed stellar evolution equations and the simple model is made. Results of the evolution of a few binary systems are reported and compared with previously published calculations using normal stellar evolution programs. (author)
A Bayesian model for binary Markov chains
Directory of Open Access Journals (Sweden)
Belkheir Essebbar
2004-02-01
Full Text Available This note is concerned with Bayesian estimation of the transition probabilities of a binary Markov chain observed from heterogeneous individuals. The model is founded on the Jeffreys' prior which allows for transition probabilities to be correlated. The Bayesian estimator is approximated by means of Monte Carlo Markov chain (MCMC techniques. The performance of the Bayesian estimates is illustrated by analyzing a small simulated data set.
ACOUSTIC EFFECTS ON BINARY AEROELASTICITY MODEL
Directory of Open Access Journals (Sweden)
Kok Hwa Yu
2011-10-01
Full Text Available Acoustics is the science concerned with the study of sound. The effects of sound on structures attract overwhelm interests and numerous studies were carried out in this particular area. Many of the preliminary investigations show that acoustic pressure produces significant influences on structures such as thin plate, membrane and also high-impedance medium like water (and other similar fluids. Thus, it is useful to investigate the structure response with the presence of acoustics on aircraft, especially on aircraft wings, tails and control surfaces which are vulnerable to flutter phenomena. The present paper describes the modeling of structural-acoustic interactions to simulate the external acoustic effect on binary flutter model. Here, the binary flutter model which illustrated as a rectangular wing is constructed using strip theory with simplified unsteady aerodynamics involving flap and pitch degree of freedom terms. The external acoustic excitation, on the other hand, is modeled using four-node quadrilateral isoparametric element via finite element approach. Both equations then carefully coupled and solved using eigenvalue solution. The mentioned approach is implemented in MATLAB and the outcome of the simulated result are later described, analyzed and illustrated in this paper.
A binary neutron star GRB model
International Nuclear Information System (INIS)
Wilson, J.R.; Salmonson, J.D.; Wilson, J.R.; Mathews, G.J.
1998-01-01
In this paper we present the preliminary results of a model for the production of gamma-ray bursts (GRBs) through the compressional heating of binary neutron stars near their last stable orbit prior to merger. Recent numerical studies of the general relativistic (GR) hydrodynamics in three spatial dimensions of close neutron star binaries (NSBs) have uncovered evidence for the compression and heating of the individual neutron stars (NSs) prior to merger 12. This effect will have significant effect on the production of gravitational waves, neutrinos and, ultimately, energetic photons. The study of the production of these photons in close NSBs and, in particular, its correspondence to observed GRBs is the subject of this paper. The gamma-rays arise as follows. Compressional heating causes the neutron stars to emit neutrino pairs which, in turn, annihilate to produce a hot electron-positron pair plasma. This pair-photon plasma expands rapidly until it becomes optically thin, at which point the photons are released. We show that this process can indeed satisfy three basic requirements of a model for cosmological gamma-ray bursts: (1) sufficient gamma-ray energy release (>10 51 ergs) to produce observed fluxes, (2) a time-scale of the primary burst duration consistent with that of a 'classical' GRB (∼10 seconds), and (3) the peak of the photon number spectrum matches that of 'classical' GRB (∼300 keV). copyright 1998 American Institute of Physics
Modeling and analysis of advanced binary cycles
Energy Technology Data Exchange (ETDEWEB)
Gawlik, K.
1997-12-31
A computer model (Cycle Analysis Simulation Tool, CAST) and a methodology have been developed to perform value analysis for small, low- to moderate-temperature binary geothermal power plants. The value analysis method allows for incremental changes in the levelized electricity cost (LEC) to be determined between a baseline plant and a modified plant. Thermodynamic cycle analyses and component sizing are carried out in the model followed by economic analysis which provides LEC results. The emphasis of the present work is on evaluating the effect of mixed working fluids instead of pure fluids on the LEC of a geothermal binary plant that uses a simple Organic Rankine Cycle. Four resources were studied spanning the range of 265{degrees}F to 375{degrees}F. A variety of isobutane and propane based mixtures, in addition to pure fluids, were used as working fluids. This study shows that the use of propane mixtures at a 265{degrees}F resource can reduce the LEC by 24% when compared to a base case value that utilizes commercial isobutane as its working fluid. The cost savings drop to 6% for a 375{degrees}F resource, where an isobutane mixture is favored. Supercritical cycles were found to have the lowest cost at all resources.
Accuracy of binary black hole waveform models for aligned-spin binaries
Kumar, Prayush; Chu, Tony; Fong, Heather; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela
2016-05-01
Coalescing binary black holes are among the primary science targets for second generation ground-based gravitational wave detectors. Reliable gravitational waveform models are central to detection of such systems and subsequent parameter estimation. This paper performs a comprehensive analysis of the accuracy of recent waveform models for binary black holes with aligned spins, utilizing a new set of 84 high-accuracy numerical relativity simulations. Our analysis covers comparable mass binaries (mass-ratio 1 ≤q ≤3 ), and samples independently both black hole spins up to a dimensionless spin magnitude of 0.9 for equal-mass binaries and 0.85 for unequal mass binaries. Furthermore, we focus on the high-mass regime (total mass ≳50 M⊙ ). The two most recent waveform models considered (PhenomD and SEOBNRv2) both perform very well for signal detection, losing less than 0.5% of the recoverable signal-to-noise ratio ρ , except that SEOBNRv2's efficiency drops slightly for both black hole spins aligned at large magnitude. For parameter estimation, modeling inaccuracies of the SEOBNRv2 model are found to be smaller than systematic uncertainties for moderately strong GW events up to roughly ρ ≲15 . PhenomD's modeling errors are found to be smaller than SEOBNRv2's, and are generally irrelevant for ρ ≲20 . Both models' accuracy deteriorates with increased mass ratio, and when at least one black hole spin is large and aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical relativity simulation in the merger phase, for unequal masses and simultaneously both black hole spins very large and aligned. Two older waveform models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected from all four waveform models during parameter estimation for several recovered binary parameters: chirp mass, mass ratio, and effective spin.
Star formation history: Modeling of visual binaries
Gebrehiwot, Y. M.; Tessema, S. B.; Malkov, O. Yu.; Kovaleva, D. A.; Sytov, A. Yu.; Tutukov, A. V.
2018-05-01
Most stars form in binary or multiple systems. Their evolution is defined by masses of components, orbital separation and eccentricity. In order to understand star formation and evolutionary processes, it is vital to find distributions of physical parameters of binaries. We have carried out Monte Carlo simulations in which we simulate different pairing scenarios: random pairing, primary-constrained pairing, split-core pairing, and total and primary pairing in order to get distributions of binaries over physical parameters at birth. Next, for comparison with observations, we account for stellar evolution and selection effects. Brightness, radius, temperature, and other parameters of components are assigned or calculated according to approximate relations for stars in different evolutionary stages (main-sequence stars, red giants, white dwarfs, relativistic objects). Evolutionary stage is defined as a function of system age and component masses. We compare our results with the observed IMF, binarity rate, and binary mass-ratio distributions for field visual binaries to find initial distributions and pairing scenarios that produce observed distributions.
Physics Of Eclipsing Binaries. II. Towards the Increased Model Fidelity
Prša, Andrej; Conroy, Kyle E.; Horvat, Martin; Pablo, Herbert; Kochoska, Angela; Bloemen, Steven; Giammarco, Joseph; Hambleton, Kelly M.; Degroote, Pieter
2016-01-01
The precision of photometric and spectroscopic observations has been systematically improved in the last decade, mostly thanks to space-borne photometric missions and ground-based spectrographs dedicated to finding exoplanets. The field of eclipsing binary stars strongly benefited from this development. Eclipsing binaries serve as critical tools for determining fundamental stellar properties (masses, radii, temperatures and luminosities), yet the models are not capable of reproducing observed...
Modeling AGN outbursts from supermassive black hole binaries
Directory of Open Access Journals (Sweden)
Tanaka T.
2012-12-01
Full Text Available When galaxies merge to assemble more massive galaxies, their nuclear supermassive black holes (SMBHs should form bound binaries. As these interact with their stellar and gaseous environments, they will become increasingly compact, culminating in inspiral and coalescence through the emission of gravitational radiation. Because galaxy mergers and interactions are also thought to fuel star formation and nuclear black hole activity, it is plausible that such binaries would lie in gas-rich environments and power active galactic nuclei (AGN. The primary difference is that these binaries have gravitational potentials that vary – through their orbital motion as well as their orbital evolution – on humanly tractable timescales, and are thus excellent candidates to give rise to coherent AGN variability in the form of outbursts and recurrent transients. Although such electromagnetic signatures would be ideally observed concomitantly with the binary’s gravitational-wave signatures, they are also likely to be discovered serendipitously in wide-field, high-cadence surveys; some may even be confused for stellar tidal disruption events. I discuss several types of possible “smoking gun” AGN signatures caused by the peculiar geometry predicted for accretion disks around SMBH binaries.
Radio emission from symbiotic stars: a binary model
International Nuclear Information System (INIS)
Taylor, A.R.; Seaquist, E.R.
1985-01-01
The authors examine a binary model for symbiotic stars to account for their radio properties. The system is comprised of a cool, mass-losing star and a hot companion. Radio emission arises in the portion of the stellar wind photo-ionized by the hot star. Computer simulations for the case of uniform mass loss at constant velocity show that when less than half the wind is ionized, optically thick spectral indices greater than +0.6 are produced. Model fits to radio spectra allow the binary separation, wind density and ionizing photon luminosity to be calculated. They apply the model to the symbiotic star H1-36. (orig.)
Modeling the effects of binary mixtures on survival in time.
Baas, J.; van Houte, B.P.P.; van Gestel, C.A.M.; Kooijman, S.A.L.M.
2007-01-01
In general, effects of mixtures are difficult to describe, and most of the models in use are descriptive in nature and lack a strong mechanistic basis. The aim of this experiment was to develop a process-based model for the interpretation of mixture toxicity measurements, with effects of binary
Evolutionary models of early-type contact binary SV Centauri
Energy Technology Data Exchange (ETDEWEB)
Nakamura, Y; Saio, H [Tohoku Univ., Sendai (Japan). Faculty of Science; Sugimoto, Daiichiro
1978-12-01
Models of the early-type contact binary system SV Centauri are computed with a binary-star evolution program. The effects of mass exchange, i.e., the effects of mass acceptance as well as mass loss, are properly included. With the initial masses of the component stars as 12.4 and 8.0 M sub(solar mass), the following observed configurations are well reproduced; the component stars are definitely in contact and the rate of mass exchange is 4 x 10/sup -4/ M sub(solar mass)yr/sup -1/. The more massive component is less luminous and has a lower effective temperature. Such features are also reproduced quantitatively. Agreement of the computed models with observation indicates that the binary system SV Cen is actually in the phase of rapid mass exchange preceding the mass-ratio reversal.
Accuracy of Binary Black Hole Waveform Models for Advanced LIGO
Kumar, Prayush; Fong, Heather; Barkett, Kevin; Bhagwat, Swetha; Afshari, Nousha; Chu, Tony; Brown, Duncan; Lovelace, Geoffrey; Pfeiffer, Harald; Scheel, Mark; Szilagyi, Bela; Simulating Extreme Spacetimes (SXS) Team
2016-03-01
Coalescing binaries of compact objects, such as black holes and neutron stars, are the primary targets for gravitational-wave (GW) detection with Advanced LIGO. Accurate modeling of the emitted GWs is required to extract information about the binary source. The most accurate solution to the general relativistic two-body problem is available in numerical relativity (NR), which is however limited in application due to computational cost. Current searches use semi-analytic models that are based in post-Newtonian (PN) theory and calibrated to NR. In this talk, I will present comparisons between contemporary models and high-accuracy numerical simulations performed using the Spectral Einstein Code (SpEC), focusing at the questions: (i) How well do models capture binary's late-inspiral where they lack a-priori accurate information from PN or NR, and (ii) How accurately do they model binaries with parameters outside their range of calibration. These results guide the choice of templates for future GW searches, and motivate future modeling efforts.
Evolutionary model of the subdwarf binary system LB3459
International Nuclear Information System (INIS)
Paczynski, B.; Dearborn, D.S.
1980-01-01
An evolutionary model is proposed for the eclipsing binary system LB 3459 (=CPD-60 0 389 = HDE 269696). The two stars are hot subdwarfs with degenerate helium cores, hydrogen burning shell sources and low mass hydrogen rich envelopes. The system probably evolved through two common envelope phases. After the first such phase it might look like the semi-detached binary AS Eri. Soon after the second common envelope phase the system might look like UU Sge, an eclipsing binary nucleus of a planetary nebula. The present mass of the optical (spectroscopic) primary is probably close to 0.24 solar mass, and the predicted radial velocity amplitude of the primary is about 150 km/s. The optical secondary should be hotter and bolometrically brighter, with a mass of 0.32 solar mass. The primary eclipse is an occultation. (author)
A binary logistic regression model with complex sampling design of ...
African Journals Online (AJOL)
2017-09-03
Sep 3, 2017 ... Bi-variable and multi-variable binary logistic regression model with complex sampling design was fitted. .... Data was entered into STATA-12 and analyzed using. SPSS-21. .... lack of access/too far or costs too much. 35. 1.2.
PHYSICS OF ECLIPSING BINARIES. II. TOWARD THE INCREASED MODEL FIDELITY
Energy Technology Data Exchange (ETDEWEB)
Prša, A.; Conroy, K. E.; Horvat, M.; Kochoska, A.; Hambleton, K. M. [Villanova University, Dept. of Astrophysics and Planetary Sciences, 800 E Lancaster Avenue, Villanova PA 19085 (United States); Pablo, H. [Université de Montréal, Pavillon Roger-Gaudry, 2900, boul. Édouard-Montpetit Montréal QC H3T 1J4 (Canada); Bloemen, S. [Radboud University Nijmegen, Department of Astrophysics, IMAPP, P.O. Box 9010, 6500 GL, Nijmegen (Netherlands); Giammarco, J. [Eastern University, Dept. of Astronomy and Physics, 1300 Eagle Road, St. Davids, PA 19087 (United States); Degroote, P. [KU Leuven, Instituut voor Sterrenkunde, Celestijnenlaan 200D, B-3001 Heverlee (Belgium)
2016-12-01
The precision of photometric and spectroscopic observations has been systematically improved in the last decade, mostly thanks to space-borne photometric missions and ground-based spectrographs dedicated to finding exoplanets. The field of eclipsing binary stars strongly benefited from this development. Eclipsing binaries serve as critical tools for determining fundamental stellar properties (masses, radii, temperatures, and luminosities), yet the models are not capable of reproducing observed data well, either because of the missing physics or because of insufficient precision. This led to a predicament where radiative and dynamical effects, insofar buried in noise, started showing up routinely in the data, but were not accounted for in the models. PHOEBE (PHysics Of Eclipsing BinariEs; http://phoebe-project.org) is an open source modeling code for computing theoretical light and radial velocity curves that addresses both problems by incorporating missing physics and by increasing the computational fidelity. In particular, we discuss triangulation as a superior surface discretization algorithm, meshing of rotating single stars, light travel time effects, advanced phase computation, volume conservation in eccentric orbits, and improved computation of local intensity across the stellar surfaces that includes the photon-weighted mode, the enhanced limb darkening treatment, the better reflection treatment, and Doppler boosting. Here we present the concepts on which PHOEBE is built and proofs of concept that demonstrate the increased model fidelity.
Latent Classification Models for Binary Data
DEFF Research Database (Denmark)
Langseth, Helge; Nielsen, Thomas Dyhre
2009-01-01
One of the simplest, and yet most consistently well-performing set of classifiers is the naive Bayes models (a special class of Bayesian network models). However, these models rely on the (naive) assumption that all the attributes used to describe an instance are conditionally independent given t...
A complete waveform model for compact binaries on eccentric orbits
George, Daniel; Huerta, Eliu; Kumar, Prayush; Agarwal, Bhanu; Schive, Hsi-Yu; Pfeiffer, Harald; Chu, Tony; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela
2017-01-01
We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are non-spinning, and which evolve on orbits with low to moderate eccentricity. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model for black hole binaries with mass-ratios between 1 to 15 in the zero eccentricity limit over a wide range of the parameter space under consideration. We use this model to show that the gravitational wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e0 of these systems when they enter the aLIGO band at a gravitational wave frequency of 14 Hz satisfies e0GW 150914 <= 0 . 15 and e0GW 151226 <= 0 . 1 .
Modelling binary black-hole coalescence
International Nuclear Information System (INIS)
Baker, John
2003-01-01
The final burst of radiation from the coalescence of two supermassive black holes produces extraordinary gravitational wave luminosity making these events visible to LISA even out to large redshift. Interpreting such observations will require detailed theoretical models, based on general relativity. The effort to construct these models is just beginning to produce results. I describe the Lazarus approach to modelling these radiation bursts, and present recent results which indicate that the system loses, in the last few wave cycles, about 3% of its mass-energy as strongly polarized gravitational radiation
Confounding of three binary-variables counterfactual model
Liu, Jingwei; Hu, Shuang
2011-01-01
Confounding of three binary-variables counterfactual model is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate three counterfactual models: the control variable is independent of the covariate variable, the control variable has the effect on the covariate variable and the covariate variable affects the control variable. Using the ancillary information based on conditional independence hypotheses, the sufficient conditions...
Binary model for the coma cluster of galaxies
International Nuclear Information System (INIS)
Valtonen, M.J.; Byrd, G.G.
1979-01-01
We study the dynamics of galaxies in the Coma cluster and find that the cluster is probably dominated by a central binary of galaxies NGC 4874--NGC4889. We estimate their total mass to be about 3 x 10 14 M/sub sun/ by two independent methods (assuming in Hubble constant of 100 km s -1 Mpc -1 ). This binary is efficient in dynamically ejecting smaller galaxies, some of of which are seen in projection against the inner 3 0 radius of the cluster and which, if erroneously considered as bound members, cause a serious overestimate of the mass of the entire cluster. Taking account of the ejected galaxies, we estimate the total cluster mass to be 4--9 x 10 14 M/sub sun/, with a corresponding mass-to-light ratio for a typical galaxy in the range of 20--120 solar units. The origin of the secondary maximum observed in the radial surface density profile is studied. We consider it to be a remnant of a shell of galaxies which formed around the central binary. This shell expanded, then collapsed into the binary, and is now reexpanding. This is supported by the coincidence of the minimum in the cluster eccentricity and radical velocity dispersion at the same radial distance as the secondary maximum. Numerical simulations of a cluster model with a massive central binary and a spherical shell of test particles are performed, and they reproduce the observed shape, galaxy density, and radial velocity distributions in the Coma cluster fairly well. Consequences of extending the model to other clusters are discussed
The Binary System Laboratory Activities Based on Students Mental Model
Albaiti, A.; Liliasari, S.; Sumarna, O.; Martoprawiro, M. A.
2017-09-01
Generic science skills (GSS) are required to develop student conception in learning binary system. The aim of this research was to know the improvement of students GSS through the binary system labotoratory activities based on their mental model using hypothetical-deductive learning cycle. It was a mixed methods embedded experimental model research design. This research involved 15 students of a university in Papua, Indonesia. Essay test of 7 items was used to analyze the improvement of students GSS. Each items was designed to interconnect macroscopic, sub-microscopic and symbolic levels. Students worksheet was used to explore students mental model during investigation in laboratory. The increase of students GSS could be seen in their N-Gain of each GSS indicators. The results were then analyzed descriptively. Students mental model and GSS have been improved from this study. They were interconnect macroscopic and symbolic levels to explain binary systems phenomena. Furthermore, they reconstructed their mental model with interconnecting the three levels of representation in Physical Chemistry. It necessary to integrate the Physical Chemistry Laboratory into a Physical Chemistry course for effectiveness and efficiency.
Complete waveform model for compact binaries on eccentric orbits
Huerta, E. A.; Kumar, Prayush; Agarwal, Bhanu; George, Daniel; Schive, Hsi-Yu; Pfeiffer, Harald P.; Haas, Roland; Ren, Wei; Chu, Tony; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela
2017-01-01
We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are nonspinning, and which evolve on orbits with low to moderate eccentricity. The inspiral evolution is described using third-order post-Newtonian equations both for the equations of motion of the binary, and its far-zone radiation field. This latter component also includes instantaneous, tails and tails-of-tails contributions, and a contribution due to nonlinear memory. This framework reduces to the post-Newtonian approximant TaylorT4 at third post-Newtonian order in the zero-eccentricity limit. To improve phase accuracy, we also incorporate higher-order post-Newtonian corrections for the energy flux of quasicircular binaries and gravitational self-force corrections to the binding energy of compact binaries. This enhanced prescription for the inspiral evolution is combined with a fully analytical prescription for the merger-ringdown evolution constructed using a catalog of numerical relativity simulations. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model of Ref. [Y. Pan et al., Phys. Rev. D 89, 061501 (2014)., 10.1103/PhysRevD.89.061501] for quasicircular black hole binaries with mass ratios between 1 to 15 in the zero-eccentricity limit over a wide range of the parameter space under consideration. Using a set of eccentric numerical relativity simulations, not used during calibration, we show that our new eccentric model reproduces the true features of eccentric compact binary coalescence throughout merger. We use this model to show that the gravitational-wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e0 of these systems when they enter the aLIGO band at a gravitational-wave frequency of 14 Hz satisfies e0GW 150914≤0.15 and e0GW 151226≤0.1 . We also find that varying the spin
A comparison of nuclear power systems for Brazil using plutonium and binary cycles
International Nuclear Information System (INIS)
Ishiguro, Y.; Fernandes, J.E.
1985-01-01
Nuclear power systems based on plutonium cycle and binary cycle are compared taking into account natural uranium demand and reactor combination. The systems start with PWR type reactors (U5/U8) and change to systems composed exclusively of FBR type reactors or PWR-FBR symbiotic systems. Four loading modes are considered for the PWR and two for the FBR. The FBR is either a LMFBR loaded with PU/U or a LMFBR loaded the binary way. A linear and a non-linear capacity growth and two different criteria for the FBR introduction are considered. The results show that a 100 GWe permanent system can be established in 50 years in all cases, based on 300000 t of natural uranium and in case of delay in the FBR introduction and if a thermal-fast symbiotic system is chosen, a binary cycle could be more advantageous than a plutonium cycle. (F.E.) [pt
Models for the formation of binary and millisecond radio pulsars
International Nuclear Information System (INIS)
van den Heuvel, E.P.J.
1984-01-01
The peculiar combination of a relatively short pulse period and a relatively weak surface dipole magnetic field strength of binary radio pulsars finds a consistent explanation in terms of: (i) decay of the surface dipole component of neutron star magnetic fields on a timescale of (2-5).10 6 yrs, in combination with: (ii) spin up of the rotation of the neutron star during a subsequent mass-transfer phase. The two observed classes of binary radio pulsars (very close and very wide systems, respectively) are expected to have been formed by the later evolution of binaries consisting of a neutron star and a normal companion star, in which the companion was (considerably) more massive than the neutron star, or less massive than the neutron star, respectively. In the first case the companion of the neutron star in the final system will be a fairly massive white dwarf, in a circular orbit, or a neutron star in an eccentric orbit. In the second case the final companion to the neutron star will be a low-mass (approx. 0.3 Msub solar) helium white dwarf in a wide and nearly circular orbit. In systems of the second type the neutron star was most probably formed by the accretion-induced collapse of a white dwarf. This explains why PSR 1953+29 has a millisecond rotation period and why PSR 0820+02 has not. Binary coalescence models for the formation of the 1.5 millisecond pulsar appear to be viable. The companion to the neutron star may have been a low-mass red dwarf, a neutron star, or a massive (> 0.7 Msub solar) white dwarf. In the red-dwarf case the progenitor system probably was a CV binary in which the white dwarf collapsed by accretion. 66 references, 6 figures, 1 table
Percolation of binary disk systems: Modeling and theory
International Nuclear Information System (INIS)
Meeks, Kelsey; Pantoya, Michelle L.
2017-01-01
The dispersion and connectivity of particles with a high degree of polydispersity is relevant to problems involving composite material properties and reaction decomposition prediction and has been the subject of much study in the literature. This paper utilizes Monte Carlo models to predict percolation thresholds for a two-dimensional systems containing disks of two different radii. Monte Carlo simulations and spanning probability are used to extend prior models into regions of higher polydispersity than those previously considered. A correlation to predict the percolation threshold for binary disk systems is proposed based on the extended dataset presented in this work and compared to previously published correlations. Finally, a set of boundary conditions necessary for a good fit is presented, and a condition for maximizing percolation threshold for binary disk systems is suggested.
Simple model of surface roughness for binary collision sputtering simulations
Energy Technology Data Exchange (ETDEWEB)
Lindsey, Sloan J. [Institute of Solid-State Electronics, TU Wien, Floragasse 7, A-1040 Wien (Austria); Hobler, Gerhard, E-mail: gerhard.hobler@tuwien.ac.at [Institute of Solid-State Electronics, TU Wien, Floragasse 7, A-1040 Wien (Austria); Maciążek, Dawid; Postawa, Zbigniew [Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30348 Kraków (Poland)
2017-02-15
Highlights: • A simple model of surface roughness is proposed. • Its key feature is a linearly varying target density at the surface. • The model can be used in 1D/2D/3D Monte Carlo binary collision simulations. • The model fits well experimental glancing incidence sputtering yield data. - Abstract: It has been shown that surface roughness can strongly influence the sputtering yield – especially at glancing incidence angles where the inclusion of surface roughness leads to an increase in sputtering yields. In this work, we propose a simple one-parameter model (the “density gradient model”) which imitates surface roughness effects. In the model, the target’s atomic density is assumed to vary linearly between the actual material density and zero. The layer width is the sole model parameter. The model has been implemented in the binary collision simulator IMSIL and has been evaluated against various geometric surface models for 5 keV Ga ions impinging an amorphous Si target. To aid the construction of a realistic rough surface topography, we have performed MD simulations of sequential 5 keV Ga impacts on an initially crystalline Si target. We show that our new model effectively reproduces the sputtering yield, with only minor variations in the energy and angular distributions of sputtered particles. The success of the density gradient model is attributed to a reduction of the reflection coefficient – leading to increased sputtering yields, similar in effect to surface roughness.
Simple model of surface roughness for binary collision sputtering simulations
International Nuclear Information System (INIS)
Lindsey, Sloan J.; Hobler, Gerhard; Maciążek, Dawid; Postawa, Zbigniew
2017-01-01
Highlights: • A simple model of surface roughness is proposed. • Its key feature is a linearly varying target density at the surface. • The model can be used in 1D/2D/3D Monte Carlo binary collision simulations. • The model fits well experimental glancing incidence sputtering yield data. - Abstract: It has been shown that surface roughness can strongly influence the sputtering yield – especially at glancing incidence angles where the inclusion of surface roughness leads to an increase in sputtering yields. In this work, we propose a simple one-parameter model (the “density gradient model”) which imitates surface roughness effects. In the model, the target’s atomic density is assumed to vary linearly between the actual material density and zero. The layer width is the sole model parameter. The model has been implemented in the binary collision simulator IMSIL and has been evaluated against various geometric surface models for 5 keV Ga ions impinging an amorphous Si target. To aid the construction of a realistic rough surface topography, we have performed MD simulations of sequential 5 keV Ga impacts on an initially crystalline Si target. We show that our new model effectively reproduces the sputtering yield, with only minor variations in the energy and angular distributions of sputtered particles. The success of the density gradient model is attributed to a reduction of the reflection coefficient – leading to increased sputtering yields, similar in effect to surface roughness.
Enhancement of nuclear reaction rates in asymmetric binary ionic mixtures
Energy Technology Data Exchange (ETDEWEB)
Clerouin, J.; Arnault, P.; Desbiens, N. [CEA, DAM, DIF, Arpajon (France); White, A.; Ticknor, C.; Kress, J.D.; Collins, L.A. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM (United States)
2017-11-15
Using orbital-free molecular dynamics simulations we study the structure and dynamics of increasingly asymmetric mixtures such as hydrogen-carbon, hydrogen-aluminium, hydrogen-copper, and hydrogen-silver. We show that, whereas the heavy component structure is close to an effective one-component plasma (OCP), the light component appears more structured than the corresponding OCP. This effect is related to the crossover towards a Lorentz-type diffusion triggered by strongly coupled, highly charged heavy ions, and witnessed by the change of temperature scaling laws of diffusion. This over-correlation translates into an enhancement of nuclear reaction rates much higher than its classical OCP counterpart. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Modeling binary correlated responses using SAS, SPSS and R
Wilson, Jeffrey R
2015-01-01
Statistical tools to analyze correlated binary data are spread out in the existing literature. This book makes these tools accessible to practitioners in a single volume. Chapters cover recently developed statistical tools and statistical packages that are tailored to analyzing correlated binary data. The authors showcase both traditional and new methods for application to health-related research. Data and computer programs will be publicly available in order for readers to replicate model development, but learning a new statistical language is not necessary with this book. The inclusion of code for R, SAS, and SPSS allows for easy implementation by readers. For readers interested in learning more about the languages, though, there are short tutorials in the appendix. Accompanying data sets are available for download through the book s website. Data analysis presented in each chapter will provide step-by-step instructions so these new methods can be readily applied to projects. Researchers and graduate stu...
A model for the massive binary V340 Muscae
Hauck, Norbert
2016-02-01
A synthetic light curve has been fitted to photometric data from the ASAS-3 database. The parameters of the best solution are well consistent with those derived from stellar models for both components for an initial metallicity Z=0.020 and a common age of 5 Myr. Therefore, we can reliably estimate the absolute dimensions of this close eclipsing binary system. Apparently, the O-type primary star has a mass of about 22.65 Msun and a radius of 10.35 Rsun. For the secondary star, likely a late B-type dwarf, we obtain about 3.1 Msun and 2.1 Rsun. Their mass ratio of about 0.138 might be the lowest found so far in O-type binaries. [English and German online-version of this paper available under www.bav-astro.eu/rb/rb2016-2/1.html].
A re-examination of thermodynamic modelling of U-Ru binary phase diagram
Energy Technology Data Exchange (ETDEWEB)
Wang, L.C.; Kaye, M.H., E-mail: matthew.kaye@uoit.ca [University of Ontario Institute of Technology, Oshawa, ON (Canada)
2015-07-01
Ruthenium (Ru) is one of the more abundant fission products (FPs) both in fast breeder reactors and thermal reactors. Post irradiation examinations (PIE) show that both 'the white metallic phase' (MoTc-Ru-Rh-Pd) and 'the other metallic phase' (U(Pd-Rh-Ru)3) are present in spent nuclear fuels. To describe this quaternary system, binary subsystems of uranium (U) with Pd, Rh, and Ru are necessary. Presently, only the U-Ru system has been thermodynamically described but with some problems. As part of research on U-Ru-Rh-Pd quaternary system, an improved consistent thermodynamic model describing the U-Ru binary phase diagram has been obtained. (author)
Marginal and Random Intercepts Models for Longitudinal Binary Data with Examples from Criminology
Long, Jeffrey D.; Loeber, Rolf; Farrington, David P.
2009-01-01
Two models for the analysis of longitudinal binary data are discussed: the marginal model and the random intercepts model. In contrast to the linear mixed model (LMM), the two models for binary data are not subsumed under a single hierarchical model. The marginal model provides group-level information whereas the random intercepts model provides…
Almog, Assaf; Garlaschelli, Diego
2014-09-01
The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information.
International Nuclear Information System (INIS)
Almog, Assaf; Garlaschelli, Diego
2014-01-01
The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information. (paper)
Structural classification and a binary structure model for superconductors
Institute of Scientific and Technical Information of China (English)
Dong Cheng
2006-01-01
Based on structural and bonding features, a new classification scheme of superconductors is proposed to classify conductors can be partitioned into two parts, a superconducting active component and a supplementary component.Partially metallic covalent bonding is found to be a common feature in all superconducting active components, and the electron states of the atoms in the active components usually make a dominant contribution to the energy band near the Fermi surface. Possible directions to explore new superconductors are discussed based on the structural classification and the binary structure model.
Modeling adsorption of binary and ternary mixtures on microporous media
DEFF Research Database (Denmark)
Monsalvo, Matias Alfonso; Shapiro, Alexander
2007-01-01
it possible using the same equation of state to describe the thermodynamic properties of the segregated and the bulk phases. For comparison, we also used the ideal adsorbed solution theory (IAST) to describe adsorption equilibria. The main advantage of these two models is their capabilities to predict......The goal of this work is to analyze the adsorption of binary and ternary mixtures on the basis of the multicomponent potential theory of adsorption (MPTA). In the MPTA, the adsorbate is considered as a segregated mixture in the external potential field emitted by the solid adsorbent. This makes...... multicomponent adsorption equilibria on the basis of single-component adsorption data. We compare the MPTA and IAST models to a large set of experimental data, obtaining reasonable good agreement with experimental data and high degree of predictability. Some limitations of both models are also discussed....
Simple model of surface roughness for binary collision sputtering simulations
Lindsey, Sloan J.; Hobler, Gerhard; Maciążek, Dawid; Postawa, Zbigniew
2017-02-01
It has been shown that surface roughness can strongly influence the sputtering yield - especially at glancing incidence angles where the inclusion of surface roughness leads to an increase in sputtering yields. In this work, we propose a simple one-parameter model (the "density gradient model") which imitates surface roughness effects. In the model, the target's atomic density is assumed to vary linearly between the actual material density and zero. The layer width is the sole model parameter. The model has been implemented in the binary collision simulator IMSIL and has been evaluated against various geometric surface models for 5 keV Ga ions impinging an amorphous Si target. To aid the construction of a realistic rough surface topography, we have performed MD simulations of sequential 5 keV Ga impacts on an initially crystalline Si target. We show that our new model effectively reproduces the sputtering yield, with only minor variations in the energy and angular distributions of sputtered particles. The success of the density gradient model is attributed to a reduction of the reflection coefficient - leading to increased sputtering yields, similar in effect to surface roughness.
Binary neutron star mergers: Dependence on the nuclear equation of state
International Nuclear Information System (INIS)
Hotokezaka, Kenta; Kyutoku, Koutarou; Okawa, Hirotada; Shibata, Masaru; Kiuchi, Kenta
2011-01-01
We perform a numerical-relativity simulation for the merger of binary neutron stars with 6 nuclear-theory-based equations of states (EOSs) described by piecewise polytropes. Our purpose is to explore the dependence of the dynamical behavior of the binary neutron star merger and resulting gravitational waveforms on the EOS of the supernuclear-density matter. The numerical results show that the merger process and the first outcome are classified into three types: (i) a black hole is promptly formed, (ii) a short-lived hypermassive neutron star (HMNS) is formed, (iii) a long-lived HMNS is formed. The type of the merger depends strongly on the EOS and on the total mass of the binaries. For the EOS with which the maximum mass is larger than 2M · , the lifetime of the HMNS is longer than 10 ms for a total mass m 0 =2.7M · . A recent radio observation suggests that the maximum mass of spherical neutron stars is M max ≥1.97±0.04M · in one σ level. This fact and our results support the possible existence of a HMNS soon after the onset of the merger for a typical binary neutron star with m 0 =2.7M · . We also show that the torus mass surrounding the remnant black hole is correlated with the type of the merger process; the torus mass could be large, ≥0.1M · , in the case that a long-lived HMNS is formed. We also show that gravitational waves carry information of the merger process, the remnant, and the torus mass surrounding a black hole.
Numerical model for dendritic solidification of binary alloys
Felicelli, S. D.; Heinrich, J. C.; Poirier, D. R.
1993-01-01
A finite element model capable of simulating solidification of binary alloys and the formation of freckles is presented. It uses a single system of equations to deal with the all-liquid region, the dendritic region, and the all-solid region. The dendritic region is treated as an anisotropic porous medium. The algorithm uses the bilinear isoparametric element, with a penalty function approximation and a Petrov-Galerkin formulation. Numerical simulations are shown in which an NH4Cl-H2O mixture and a Pb-Sn alloy melt are cooled. The solidification process is followed in time. Instabilities in the process can be clearly observed and the final compositions obtained.
Thermochemical modeling of nuclear waste glass
International Nuclear Information System (INIS)
Spear, K.E.; Besmann, T.M.; Beahm, E.C.
1998-06-01
The development of assessed and consistent phase equilibria and thermodynamic data for major glass constituents used to incorporate high-level nuclear waste is discussed in this paper. The initial research has included the binary Na 2 O-SiO 2 , Na 2 O-Al 2 O 3 , and SiO 2 -Al 2 O 3 systems. The nuclear waste glass is assumed to be a supercooled liquid containing the constituents in the glass at temperatures of interest for nuclear waste storage. Thermodynamic data for the liquid solutions were derived from mathematical comparisons of phase diagram information and the thermodynamic data available for crystalline solid phases. An associate model is used to describe the liquid solution phases. Utilizing phase diagram information provides very stringent limits on the relative thermodynamic stabilities of all phases which exist in a given system
Modeling of columnar and equiaxed solidification of binary mixtures
International Nuclear Information System (INIS)
Roux, P.
2005-12-01
This work deals with the modelling of dendritic solidification in binary mixtures. Large scale phenomena are represented by volume averaging of the local conservation equations. This method allows to rigorously derive the partial differential equations of averaged fields and the closure problems associated to the deviations. Such problems can be resolved numerically on periodic cells, representative of dendritic structures, in order to give a precise evaluation of macroscopic transfer coefficients (Drag coefficients, exchange coefficients, diffusion-dispersion tensors...). The method had already been applied for a model of columnar dendritic mushy zone and it is extended to the case of equiaxed dendritic solidification, where solid grains can move. The two-phase flow is modelled with an Eulerian-Eulerian approach and the novelty is to account for the dispersion of solid velocity through the kinetic agitation of the particles. A coupling of the two models is proposed thanks to an original adaptation of the columnar model, allowing for undercooling calculation: a solid-liquid interfacial area density is introduced and calculated. At last, direct numerical simulations of crystal growth are proposed with a diffuse interface method for a representation of local phenomena. (author)
Modeling of formation of binary-phase hollow nanospheres from metallic solid nanospheres
International Nuclear Information System (INIS)
Svoboda, J.; Fischer, F.D.; Vollath, D.
2009-01-01
Spontaneous formation of binary-phase hollow nanospheres by reaction of a metallic nanosphere with a non-metallic component in the surrounding atmosphere is observed for many systems. The kinetic model describing this phenomenon is derived by application of the thermodynamic extremal principle. The necessary condition of formation of the binary-phase hollow nanospheres is that the diffusion coefficient of the metallic component in the binary phase is higher than that of the non-metallic component (Kirkendall effect occurs in the correct direction). The model predictions of the time to formation of the binary-phase hollow nanospheres agree with the experimental observations
Observational properties of models of semidetached close binaries. Pt. 2
International Nuclear Information System (INIS)
Giannone, P.; Giannuzzi, M.A.; Pucillo, M.
1975-01-01
Binaries of Cases A and B with intermediate and small masses have been studied. Synthetic light curves are shown to be affected mainly by the assumption concerning the shape of the components. The comparison between synthetic light curves and observed data can give further information on the reliability of the hypotheses assumed in the computations of binary star evolution. The calculated properties lead to useful indications about the evolutionary stages of observed binaries. The detection of systems evolving according to Case A appears to be favoured in comparison with that of systems of Case B. Systems with undersize subgiants result comparatively difficult to observe. (orig./BJ) [de
Sparse Representation Based Binary Hypothesis Model for Hyperspectral Image Classification
Directory of Open Access Journals (Sweden)
Yidong Tang
2016-01-01
Full Text Available The sparse representation based classifier (SRC and its kernel version (KSRC have been employed for hyperspectral image (HSI classification. However, the state-of-the-art SRC often aims at extended surface objects with linear mixture in smooth scene and assumes that the number of classes is given. Considering the small target with complex background, a sparse representation based binary hypothesis (SRBBH model is established in this paper. In this model, a query pixel is represented in two ways, which are, respectively, by background dictionary and by union dictionary. The background dictionary is composed of samples selected from the local dual concentric window centered at the query pixel. Thus, for each pixel the classification issue becomes an adaptive multiclass classification problem, where only the number of desired classes is required. Furthermore, the kernel method is employed to improve the interclass separability. In kernel space, the coding vector is obtained by using kernel-based orthogonal matching pursuit (KOMP algorithm. Then the query pixel can be labeled by the characteristics of the coding vectors. Instead of directly using the reconstruction residuals, the different impacts the background dictionary and union dictionary have on reconstruction are used for validation and classification. It enhances the discrimination and hence improves the performance.
Symbiotic stars - a binary model with super-critical accretion
Energy Technology Data Exchange (ETDEWEB)
Bath, G T [National Radio Astronomy Observatory, Charlottesville, Va. (USA)
1977-01-01
The structure of symbiotic variables is discussed in terms of a binary model. Disc accretion by a main sequence star or white dwarf at rates close to the Eddington limit produces an ultraviolet continuum source near the accreting star surface. This generates a variable, radiatively-driven, out-flowing wind. The wind is optically thick and the disc luminosity is absorbed and scattered and thus degraded into the optical region. Variations in the rate of mass loss in the wind lead to optical eruptions through shifts in the position of, and conditions in, the last scattering surface. The behaviour of Z And determined by Boyarchuk is shown to be in agreement with such a model. The conditions in the out-flowing wind are discussed. Limits on the mass loss rate are derived from conditions at the surface of the accreting star. It is suggested that variable out-flow in the wind is generated by fluctuations in disc luminosity produced by changes in the giant companions rate of mass transfer. The relation between symbiotic variables and classical and dwarf novae is discussed.
Unobserved Heterogeneity in the Binary Logit Model with Cross-Sectional Data and Short Panels
DEFF Research Database (Denmark)
Holm, Anders; Jæger, Mads Meier; Pedersen, Morten
This paper proposes a new approach to dealing with unobserved heterogeneity in applied research using the binary logit model with cross-sectional data and short panels. Unobserved heterogeneity is particularly important in non-linear regression models such as the binary logit model because, unlike...... in linear regression models, estimates of the effects of observed independent variables are biased even when omitted independent variables are uncorrelated with the observed independent variables. We propose an extension of the binary logit model based on a finite mixture approach in which we conceptualize...
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Iona M.S. de; Schirru, Roberto, E-mail: ioliveira@con.ufrj.br, E-mail: schirru@lmp.ufrj.br [Coordenacoa dos Programas de Pos-Graduacao em Engenharia (UFRJ/PEN/COPPE), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear
2011-07-01
The identification of possible transients in a nuclear power plant is a highly relevant problem. This is mainly due to the fact that the operation of a nuclear power plant involves a large number of state variables whose behaviors are extremely dynamic. In risk situations, besides the huge cognitive overload that operators are submitted to, there is also the problem related with the considerable decrease in the effective time for correct decision making. To minimize these problems and help operators to make the corrective actions in due time, this paper presents a new contribution in this area and introduces an experimental transient identification system based exclusively on the abilities of the Discrete Binary Artificial Bee Colony (DBABC) algorithm to find the best centroid positions that correctly identifies a transient in a nuclear power plant. The DBABC is a reworking of the Artificial Bee Colony (ABC) algorithm which presents the advantage of operating in both continuous and discrete search spaces. Through the analysis of experimental results, the effective performance of the proposed DBABC algorithm is shown against some well known best performing algorithms from the literature. (author)
International Nuclear Information System (INIS)
Oliveira, Iona M.S. de; Schirru, Roberto
2011-01-01
The identification of possible transients in a nuclear power plant is a highly relevant problem. This is mainly due to the fact that the operation of a nuclear power plant involves a large number of state variables whose behaviors are extremely dynamic. In risk situations, besides the huge cognitive overload that operators are submitted to, there is also the problem related with the considerable decrease in the effective time for correct decision making. To minimize these problems and help operators to make the corrective actions in due time, this paper presents a new contribution in this area and introduces an experimental transient identification system based exclusively on the abilities of the Discrete Binary Artificial Bee Colony (DBABC) algorithm to find the best centroid positions that correctly identifies a transient in a nuclear power plant. The DBABC is a reworking of the Artificial Bee Colony (ABC) algorithm which presents the advantage of operating in both continuous and discrete search spaces. Through the analysis of experimental results, the effective performance of the proposed DBABC algorithm is shown against some well known best performing algorithms from the literature. (author)
Modeling and analysis of periodic orbits around a contact binary asteroid
Feng, J.; Noomen, R.; Visser, P.N.A.M.; Yuan, J.
2015-01-01
The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is
Thermodynamics Properties of Binary Gas Mixtures for Brayton Space Nuclear Power System
International Nuclear Information System (INIS)
You Ersheng; Shi Lei; Zhang Zuoyi
2014-01-01
Space nuclear power system with closed Brayton cycle has the potential advantages of high cycle efficiency. It can be achieved to limit the specific mass of the system with a competitive design scheme, so as to strengthen the advantage of the nuclear energy applying in space propulsion and electric generating compared to solar or chemical propellant. Whereby, the thermodynamic properties of working fluids have a significant influence on the performance of the plant. Therefore, two binary mixtures helium-nitrogen and helium-carbon dioxide are introduced to analysis the variation in the transport and heat transfer capacity of working fluids. Based on the parameters of pure gases, the heat transfer coefficient, pressure losses and aerodynamic loading are calculated as a function of mole fraction at the temperature of 400 K and 1200 K, as well as the typical operating pressure of 2 MPa. Results indicated that the mixture of helium-carbon dioxide with a mole fraction of 0.4 is a more attractive choice for the high heat transfer coefficient, low aerodynamic loading and acceptable pressure losses in contrast to helium-nitrogen and other mixing ratios of helium-carbon dioxide. Its heat transfer coefficient is almost 20% more than that of pure helium and the normalized aerodynamic loading is less than 34% at 1200 K. However; the pressure losses are a little higher with ~3.5 times those of pure helium. (author)
Massive Black Hole Binary Evolution
Directory of Open Access Journals (Sweden)
Merritt David
2005-11-01
Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.
Hybrid approach for the assessment of PSA models by means of binary decision diagrams
International Nuclear Information System (INIS)
Ibanez-Llano, Cristina; Rauzy, Antoine; Melendez, Enrique; Nieto, Francisco
2010-01-01
Binary decision diagrams are a well-known alternative to the minimal cutsets approach to assess the reliability Boolean models. They have been applied successfully to improve the fault trees models assessment. However, its application to solve large models, and in particular the event trees coming from the PSA studies of the nuclear industry, remains to date out of reach of an exact evaluation. For many real PSA models it may be not possible to compute the BDD within reasonable amount of time and memory without considering the truncation or simplification of the model. This paper presents a new approach to estimate the exact probabilistic quantification results (probability/frequency) based on combining the calculation of the MCS and the truncation limits, with the BDD approach, in order to have a better control on the reduction of the model and to properly account for the success branches. The added value of this methodology is that it is possible to ensure a real confidence interval of the exact value and therefore an explicit knowledge of the error bound. Moreover, it can be used to measure the acceptability of the results obtained with traditional techniques. The new method was applied to a real life PSA study and the results obtained confirm the applicability of the methodology and open a new viewpoint for further developments.
Hybrid approach for the assessment of PSA models by means of binary decision diagrams
Energy Technology Data Exchange (ETDEWEB)
Ibanez-Llano, Cristina, E-mail: cristina.ibanez@iit.upcomillas.e [Instituto de Investigacion Tecnologica (IIT), Escuela Tecnica Superior de Ingenieria ICAI, Universidad Pontificia Comillas, C/Santa Cruz de Marcenado 26, 28015 Madrid (Spain); Rauzy, Antoine, E-mail: Antoine.RAUZY@3ds.co [Dassault Systemes, 10 rue Marcel Dassault CS 40501, 78946 Velizy Villacoublay Cedex (France); Melendez, Enrique, E-mail: ema@csn.e [Consejo de Seguridad Nuclear (CSN), C/Justo Dorado 11, 28040 Madrid (Spain); Nieto, Francisco, E-mail: nieto@iit.upcomillas.e [Instituto de Investigacion Tecnologica (IIT), Escuela Tecnica Superior de Ingenieria ICAI, Universidad Pontificia Comillas, C/Santa Cruz de Marcenado 26, 28015 Madrid (Spain)
2010-10-15
Binary decision diagrams are a well-known alternative to the minimal cutsets approach to assess the reliability Boolean models. They have been applied successfully to improve the fault trees models assessment. However, its application to solve large models, and in particular the event trees coming from the PSA studies of the nuclear industry, remains to date out of reach of an exact evaluation. For many real PSA models it may be not possible to compute the BDD within reasonable amount of time and memory without considering the truncation or simplification of the model. This paper presents a new approach to estimate the exact probabilistic quantification results (probability/frequency) based on combining the calculation of the MCS and the truncation limits, with the BDD approach, in order to have a better control on the reduction of the model and to properly account for the success branches. The added value of this methodology is that it is possible to ensure a real confidence interval of the exact value and therefore an explicit knowledge of the error bound. Moreover, it can be used to measure the acceptability of the results obtained with traditional techniques. The new method was applied to a real life PSA study and the results obtained confirm the applicability of the methodology and open a new viewpoint for further developments.
International Nuclear Information System (INIS)
Binh, Do Quang; Huy, Ngo Quang; Hai, Nguyen Hoang
2014-01-01
This paper presents a new approach based on a binary mixed integer coded genetic algorithm in conjunction with the weighted sum method for multi-objective optimization of fuel loading patterns for nuclear research reactors. The proposed genetic algorithm works with two types of chromosomes: binary and integer chromosomes, and consists of two types of genetic operators: one working on binary chromosomes and the other working on integer chromosomes. The algorithm automatically searches for the most suitable weighting factors of the weighting function and the optimal fuel loading patterns in the search process. Illustrative calculations are implemented for a research reactor type TRIGA MARK II loaded with the Russian VVR-M2 fuels. Results show that the proposed genetic algorithm can successfully search for both the best weighting factors and a set of approximate optimal loading patterns that maximize the effective multiplication factor and minimize the power peaking factor while satisfying operational and safety constraints for the research reactor.
Energy Technology Data Exchange (ETDEWEB)
Binh, Do Quang [University of Technical Education Ho Chi Minh City (Viet Nam); Huy, Ngo Quang [University of Industry Ho Chi Minh City (Viet Nam); Hai, Nguyen Hoang [Centre for Research and Development of Radiation Technology, Ho Chi Minh City (Viet Nam)
2014-12-15
This paper presents a new approach based on a binary mixed integer coded genetic algorithm in conjunction with the weighted sum method for multi-objective optimization of fuel loading patterns for nuclear research reactors. The proposed genetic algorithm works with two types of chromosomes: binary and integer chromosomes, and consists of two types of genetic operators: one working on binary chromosomes and the other working on integer chromosomes. The algorithm automatically searches for the most suitable weighting factors of the weighting function and the optimal fuel loading patterns in the search process. Illustrative calculations are implemented for a research reactor type TRIGA MARK II loaded with the Russian VVR-M2 fuels. Results show that the proposed genetic algorithm can successfully search for both the best weighting factors and a set of approximate optimal loading patterns that maximize the effective multiplication factor and minimize the power peaking factor while satisfying operational and safety constraints for the research reactor.
International Nuclear Information System (INIS)
Santos, Ivan; Marques, Luis A.; Pelaz, Lourdes; Lopez, Pedro
2007-01-01
In this paper, we present classical molecular dynamics results about the formation of amorphous pockets in silicon for energy transfers below the displacement threshold. While in binary collision simulations ions with different masses generate the same number of Frenkel pairs for the same deposited nuclear energy, in molecular dynamics simulations the amount of damage and its complexity increase with ion mass. We demonstrate that low-energy transfers to target atoms are able to generate complex damage structures. We have determined the conditions that have to be fulfilled to produce amorphous pockets, showing that the order-disorder transition depends on the particular competition between melting and heat diffusion processes. We have incorporated these molecular dynamics results in an improved binary collision model that is able to provide a good description of damage with a very low computational cost
Kenyon, Amy; Gavriouchkina, Daria; Zorman, Jernej; Chong-Morrison, Vanessa; Napolitani, Giorgio; Cerundolo, Vincenzo; Sauka-Spengler, Tatjana
2018-04-06
A complex network of inflammatory genes is closely linked to somatic cell transformation and malignant disease. Immune cells and their associated molecules are responsible for detecting and eliminating cancer cells as they establish themselves as the precursors of a tumour. By the time a patient has a detectable solid tumour, cancer cells have escaped the initial immune response mechanisms. Here, we describe the development of a double binary zebrafish model that enables regulatory programming of the myeloid cells as they respond to oncogene-activated melanocytes to be explored, focussing on the initial phase when cells become the precursors of cancer. A hormone-inducible binary system allows for temporal control of expression of different Ras oncogenes ( NRas Q61K , HRas G12V and KRas G12V ) in melanocytes, leading to proliferation and changes in morphology of the melanocytes. This model was coupled to binary cell-specific biotagging models allowing in vivo biotinylation and subsequent isolation of macrophage or neutrophil nuclei for regulatory profiling of their active transcriptomes. Nuclear transcriptional profiling of neutrophils, performed as they respond to the earliest precursors of melanoma in vivo , revealed an intricate landscape of regulatory factors that may promote progression to melanoma, including Serpinb1l4, Fgf1, Fgf6, Cathepsin H, Galectin 1 and Galectin 3. The model presented here provides a powerful platform to study the myeloid response to the earliest precursors of melanoma. © 2018. Published by The Company of Biologists Ltd.
A model of two-stream non-radial accretion for binary X-ray pulsars
International Nuclear Information System (INIS)
Lipunov, V.M.
1982-01-01
The general case of non-radial accretion is assumed to occur in real binary systems containing X-ray pulsars. The structure and the stability of the magnetosphere, the interaction between the magnetosphere and accreted matter, as well as evolution of neutron star in close binary system are examined within the framework of the two-stream model of nonradial accretion onto a magnetized neutron star. Observable parameters of X-ray pulsars are explained in terms of the model considered. (orig.)
Unveiling the equation of state of nuclear matter with binary neutron stars
Energy Technology Data Exchange (ETDEWEB)
Galeazzi, F.; Rezzolla, L. [Frankfurt Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics
2016-11-01
2015 marked the hundred anniversary of Albert Einstein's lecture at the Prussian Academy of Science in which he introduced, for the first time, the famous field equations which became the core of his theory of general relativity. This masterpiece of 20th century science has proven extremely solid in all its predictions from the precession of the perihelion of Mercury to the observation of gravitational lensing in distant galaxies, to the more mundane time-delay corrections required by the global positioning system. One last piece of the puzzle is although still missing and comprise the direct measurement of the gravitational wave (GW) radiation emitted by any accelerating mass. These ripples in the spacetime fabric are extremely weak even when produced in the most extreme of the conditions as the ones present during the mergers of two black holes or neutron stars. For this reason they have eluded experimental scientists for almost four decades. But things are about to change, last year a new array of advanced gravitational wave detectors, namely advanced LIGO and Virgo came online in late September and they are expected to observe up to 40 events per year involving the mergers of two compact objects. Despite the high sensitivity of this generation of ground base interferometers, it is still necessary to use accurate gravitational waveforms models to extract all the information from the signal produced by the detector. In this project we focus on the merger of two neutron stars which orbit together in a binary system. The nonlinear nature of the Einstein equations coupled with the complex microphysics behind neutron star matter requires the use of sophisticated codes which uses advanced numerical techniques to produce accurate results. By using the GW signals calculated in our numerical simulations we will be able to strongly link the properties of neutron star matter to a precise set of observable frequencies from the detector. This information, together with
Lach, Theodore
2017-01-01
The Checkerboard model of the Nucleus has been in the public domain for over 20 years. Over those years it has been described by nuclear and particle physicists as; cute, ``the Bohr model of the nucleus'' and ``reminiscent of the Eightfold Way''. It has also been ridiculed as numerology, laughed at, and even worse. In 2000 the theory was taken to the next level by attempting to explain why the mass of the ``up'' and ``dn'' quarks were significantly heavier than the SM ``u'' and ``d'' quarks. This resulted in a paper published on arXiv.nucl-th/0008026 in 2000, predicting 5 generations of quarks, each quark and negative lepton particle related to each other by a simple geometric mean. The CBM predicts that the radii of the elementary particles are proportional to the cube root of their masses. This was realized Pythagorean musical intervals (octave, perfect 5th, perfect 4th plus two others). Therefore each generation can be explained by a simple right triangle and the height of the hypotenuse. Notice that the height of a right triangle breaks the hypotenuse into two line segments. The geometric mean of those two segments equals the length of the height of this characteristic triangle. Therefore the CBM theory now predicts that all the elementary particles mass are proportion to the cube of their radii. Therefore the mass density of all elementary particles (and perhaps black holes too) are a constant of nature.
Modeling nuclear processes by Simulink
Energy Technology Data Exchange (ETDEWEB)
Rashid, Nahrul Khair Alang Md, E-mail: nahrul@iium.edu.my [Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak, Selangor (Malaysia)
2015-04-29
Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox software that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples.
Modeling nuclear processes by Simulink
International Nuclear Information System (INIS)
Rashid, Nahrul Khair Alang Md
2015-01-01
Modelling and simulation are essential parts in the study of dynamic systems behaviours. In nuclear engineering, modelling and simulation are important to assess the expected results of an experiment before the actual experiment is conducted or in the design of nuclear facilities. In education, modelling can give insight into the dynamic of systems and processes. Most nuclear processes can be described by ordinary or partial differential equations. Efforts expended to solve the equations using analytical or numerical solutions consume time and distract attention from the objectives of modelling itself. This paper presents the use of Simulink, a MATLAB toolbox software that is widely used in control engineering, as a modelling platform for the study of nuclear processes including nuclear reactor behaviours. Starting from the describing equations, Simulink models for heat transfer, radionuclide decay process, delayed neutrons effect, reactor point kinetic equations with delayed neutron groups, and the effect of temperature feedback are used as examples
Global nuclear material control model
International Nuclear Information System (INIS)
Dreicer, J.S.; Rutherford, D.A.
1996-01-01
The nuclear danger can be reduced by a system for global management, protection, control, and accounting as part of a disposition program for special nuclear materials. The development of an international fissile material management and control regime requires conceptual research supported by an analytical and modeling tool that treats the nuclear fuel cycle as a complete system. Such a tool must represent the fundamental data, information, and capabilities of the fuel cycle including an assessment of the global distribution of military and civilian fissile material inventories, a representation of the proliferation pertinent physical processes, and a framework supportive of national or international perspective. They have developed a prototype global nuclear material management and control systems analysis capability, the Global Nuclear Material Control (GNMC) model. The GNMC model establishes the framework for evaluating the global production, disposition, and safeguards and security requirements for fissile nuclear material
Finite-element solidification modelling of metals and binary alloys
International Nuclear Information System (INIS)
Mathew, P.M.
1986-12-01
In the Canadian Nuclear Fuel Waste Management Program, cast metals and alloys are being evaluated for their ability to support a metallic fuel waste container shell under disposal vault conditions and to determine their performance as an additional barrier to radionuclide release. These materials would be cast to fill residual free space inside the container and allowed to solidify without major voids. To model their solidification characteristics following casting, a finite-element model, FAXMOD-3, was adopted. Input parameters were modified to account for the latent heat of fusion of the metals and alloys considered. This report describes the development of the solidification model and its theoretical verification. To model the solidification of pure metals and alloys that melt at a distinct temperature, the latent heat of fusion was incorporated as a double-ramp function in the specific heat-temperature relationship, within an interval of +- 1 K around the solidification temperature. Comparison of calculated results for lead, tin and lead-tin eutectic melts, unidirectionally cooled with and without superheat, showed good agreement with an alternative technique called the integral profile method. To model the solidification of alloys that melt over a temperature interval, the fraction of solid in the solid-liquid region, as calculated from the Scheil equation, was used to determine the fraction of latent heat to be liberated over a temperature interval within the solid-liquid zone. Comparison of calculated results for unidirectionally cooled aluminum-4 wt.% copper melt, with and without superheat, showed good agreement with alternative finite-difference techniques
International Nuclear Information System (INIS)
Babak, S; Balasubramanian, R; Churches, D; Cokelaer, T; Sathyaprakash, B S
2006-01-01
Gravitational waves from coalescing compact binaries are searched for using the matched filtering technique. As the model waveform depends on a number of parameters, it is necessary to filter the data through a template bank covering the astrophysically interesting region of the parameter space. The choice of templates is defined by the maximum allowed drop in signal-to-noise ratio due to the discreteness of the template bank. In this paper we describe the template-bank algorithm that was used in the analysis of data from the Laser Interferometer Gravitational Wave Observatory (LIGO) and GEO 600 detectors to search for signals from binaries consisting of non-spinning compact objects. Using Monte Carlo simulations, we study the efficiency of the bank and show that its performance is satisfactory for the design sensitivity curves of ground-based interferometric gravitational wave detectors GEO 600, initial LIGO, advanced LIGO and Virgo. The bank is efficient in searching for various compact binaries such as binary primordial black holes, binary neutron stars, binary black holes, as well as a mixed binary consisting of a non-spinning black hole and a neutron star
Spatio-kinematic modelling: Testing the link between planetary nebulae and close binaries
Jones, David; Tyndall, Amy A.; Huckvale, Leo; Prouse, Barnabas; Lloyd, Myfanwy
2011-01-01
It is widely believed that central star binarity plays an important role in the formation and evolution of aspherical planetary nebulae, however observational support for this hypothesis is lacking. Here, we present the most recent results of a continuing programme to model the morphologies of all planetary nebulae known to host a close binary central star. Initially, this programme allows us to compare the inclination of the nebular symmetry axis to that of the binary plane, testing the theo...
Physics of Eclipsing Binaries: Modelling in the new era of ultra-high precision photometry
Pavlovski, K.; Bloemen, S.; Degroote, P.; Conroy, K.; Hambleton, Kelly; Giammarco, J.M.; Pablo, H.; Prša, A.; Tkachenko, A.; Torres, G.
2013-01-01
Recent ultra-high precision observations of eclipsing binaries, especially data acquired by the Kepler satellite, have made accurate light curve modelling increasingly challenging but also more rewarding. In this contribution, we discuss low-amplitude signals in light curves that can now be used to derive physical information about eclipsing binaries but that were unaccessible before the Kepler era. A notable example is the detection of Doppler beaming, which leads to an increase in flux when...
Physics of Eclipsing Binaries: Motivation for the New-Age Modeling Suite
Pavlovski, K.; Prša, A.; Degroote, P.; Conroy, K.; Bloemen, S.; Hambleton, Kelly; Giammarco, J.; Pablo, H.; Tkachenko, A.; Torres, G.
2013-01-01
Recent ultra-high precision observations of eclipsing binaries, especially data acquired by the Kepler satellite, have made accurate light curve modelling increasingly challenging but also more rewarding. In this contribution, we discuss low-amplitude signals in light curves that can now be used to derive physical information about eclipsing binaries but that were unaccessible before the Kepler era. A notable example is the detection of Doppler beaming, which leads to an increase in flux when...
International Nuclear Information System (INIS)
Fang Zheng; Zhang Quanru
2006-01-01
A model has been derived to predict thermodynamic properties of ternary metallic systems from those of its three binaries. In the model, the excess Gibbs free energies and the interaction parameter ω 123 for three components of a ternary are expressed as a simple sum of those of the three sub-binaries, and the mole fractions of the components of the ternary are identical with the sub-binaries. This model is greatly simplified compared with the current symmetrical and asymmetrical models. It is able to overcome some shortcomings of the current models, such as the arrangement of the components in the Gibbs triangle, the conversion of mole fractions between ternary and corresponding binaries, and some necessary processes for optimizing the various parameters of these models. Two ternary systems, Mg-Cu-Ni and Cd-Bi-Pb are recalculated to demonstrate the validity and precision of the present model. The calculated results on the Mg-Cu-Ni system are better than those in the literature. New parameters in the Margules equations expressing the excess Gibbs free energies of three binary systems of the Cd-Bi-Pb ternary system are also given
Uncertainties in Nuclear Proliferation Modeling
International Nuclear Information System (INIS)
Kim, Chul Min; Yim, Man-Sung; Park, Hyeon Seok
2015-01-01
There have been various efforts in the research community to understand the determinants of nuclear proliferation and develop quantitative tools to predict nuclear proliferation events. Such systematic approaches have shown the possibility to provide warning for the international community to prevent nuclear proliferation activities. However, there are still large debates for the robustness of the actual effect of determinants and projection results. Some studies have shown that several factors can cause uncertainties in previous quantitative nuclear proliferation modeling works. This paper analyzes the uncertainties in the past approaches and suggests future works in the view of proliferation history, analysis methods, and variable selection. The research community still lacks the knowledge for the source of uncertainty in current models. Fundamental problems in modeling will remain even other advanced modeling method is developed. Before starting to develop fancy model based on the time dependent proliferation determinants' hypothesis, using graph theory, etc., it is important to analyze the uncertainty of current model to solve the fundamental problems of nuclear proliferation modeling. The uncertainty from different proliferation history coding is small. Serious problems are from limited analysis methods and correlation among the variables. Problems in regression analysis and survival analysis cause huge uncertainties when using the same dataset, which decreases the robustness of the result. Inaccurate variables for nuclear proliferation also increase the uncertainty. To overcome these problems, further quantitative research should focus on analyzing the knowledge suggested on the qualitative nuclear proliferation studies
Photometric Analysis and Modeling of Five Mass-Transferring Binary Systems
Geist, Emily; Beaky, Matthew; Jamison, Kate
2018-01-01
In overcontact eclipsing binary systems, both stellar components have overfilled their Roche lobes, resulting in a dumbbell-shaped shared envelope. Mass transfer is common in overcontact binaries, which can be observed as a slow change on the rotation period of the system.We studied five overcontact eclipsing binary systems with evidence of period change, and thus likely mass transfer between the components, identified by Nelson (2014): V0579 Lyr, KN Vul, V0406 Lyr, V2240 Cyg, and MS Her. We used the 31-inch NURO telescope at Lowell Observatory in Flagstaff, Arizona to obtain images in B,V,R, and I filters for V0579 Lyr, and the 16-inch Meade LX200GPS telescope with attached SBIG ST-8XME CCD camera at Juniata College in Huntingdon, Pennsylvania to image KN Vul, V0406 Lyr, V2240 Cyg, and MS Her, also in B,V,R, and I.After data reduction, we created light curves for each of the systems and modeled the eclipsing binaries using the BinaryMaker3 and PHOEBE programs to determine their fundamental physical parameters for the first time. Complete light curves and preliminary models for each of these neglected eclipsing binary systems will be presented.
Cao, Zhoujian; Han, Wen-Biao
2017-08-01
Binary black hole systems are among the most important sources for gravitational wave detection. They are also good objects for theoretical research for general relativity. A gravitational waveform template is important to data analysis. An effective-one-body-numerical-relativity (EOBNR) model has played an essential role in the LIGO data analysis. For future space-based gravitational wave detection, many binary systems will admit a somewhat orbit eccentricity. At the same time, the eccentric binary is also an interesting topic for theoretical study in general relativity. In this paper, we construct the first eccentric binary waveform model based on an effective-one-body-numerical-relativity framework. Our basic assumption in the model construction is that the involved eccentricity is small. We have compared our eccentric EOBNR model to the circular one used in the LIGO data analysis. We have also tested our eccentric EOBNR model against another recently proposed eccentric binary waveform model; against numerical relativity simulation results; and against perturbation approximation results for extreme mass ratio binary systems. Compared to numerical relativity simulations with an eccentricity as large as about 0.2, the overlap factor for our eccentric EOBNR model is better than 0.98 for all tested cases, including spinless binary and spinning binary, equal mass binary, and unequal mass binary. Hopefully, our eccentric model can be the starting point to develop a faithful template for future space-based gravitational wave detectors.
London, Lionel; Khan, Sebastian; Fauchon-Jones, Edward; García, Cecilio; Hannam, Mark; Husa, Sascha; Jiménez-Forteza, Xisco; Kalaghatgi, Chinmay; Ohme, Frank; Pannarale, Francesco
2018-04-20
Gravitational-wave observations of binary black holes currently rely on theoretical models that predict the dominant multipoles (ℓ=2,|m|=2) of the radiation during inspiral, merger, and ringdown. We introduce a simple method to include the subdominant multipoles to binary black hole gravitational waveforms, given a frequency-domain model for the dominant multipoles. The amplitude and phase of the original model are appropriately stretched and rescaled using post-Newtonian results (for the inspiral), perturbation theory (for the ringdown), and a smooth transition between the two. No additional tuning to numerical-relativity simulations is required. We apply a variant of this method to the nonprecessing PhenomD model. The result, PhenomHM, constitutes the first higher-multipole model of spinning and coalescing black-hole binaries, and currently includes the (ℓ,|m|)=(2,2),(3,3),(4,4),(2,1),(3,2),(4,3) radiative moments. Comparisons with numerical-relativity waveforms demonstrate that PhenomHM is more accurate than dominant-multipole-only models for all binary configurations, and typically improves the measurement of binary properties.
First Higher-Multipole Model of Gravitational Waves from Spinning and Coalescing Black-Hole Binaries
London, Lionel; Khan, Sebastian; Fauchon-Jones, Edward; García, Cecilio; Hannam, Mark; Husa, Sascha; Jiménez-Forteza, Xisco; Kalaghatgi, Chinmay; Ohme, Frank; Pannarale, Francesco
2018-04-01
Gravitational-wave observations of binary black holes currently rely on theoretical models that predict the dominant multipoles (ℓ=2 ,|m |=2 ) of the radiation during inspiral, merger, and ringdown. We introduce a simple method to include the subdominant multipoles to binary black hole gravitational waveforms, given a frequency-domain model for the dominant multipoles. The amplitude and phase of the original model are appropriately stretched and rescaled using post-Newtonian results (for the inspiral), perturbation theory (for the ringdown), and a smooth transition between the two. No additional tuning to numerical-relativity simulations is required. We apply a variant of this method to the nonprecessing PhenomD model. The result, PhenomHM, constitutes the first higher-multipole model of spinning and coalescing black-hole binaries, and currently includes the (ℓ,|m |)=(2 ,2 ),(3 ,3 ),(4 ,4 ),(2 ,1 ),(3 ,2 ),(4 ,3 ) radiative moments. Comparisons with numerical-relativity waveforms demonstrate that PhenomHM is more accurate than dominant-multipole-only models for all binary configurations, and typically improves the measurement of binary properties.
PREDICTION OF THE MIXING ENTHALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL
Institute of Scientific and Technical Information of China (English)
H.W.Yang; D.P.Tao; Z.H.Zhou
2008-01-01
The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model (MIVM), which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted values are in agreement with the experimental data and then indicate that the model is reliable and convenient.
A globally accurate theory for a class of binary mixture models
Dickman, Adriana G.; Stell, G.
The self-consistent Ornstein-Zernike approximation results for the 3D Ising model are used to obtain phase diagrams for binary mixtures described by decorated models, yielding the plait point, binodals, and closed-loop coexistence curves for the models proposed by Widom, Clark, Neece, and Wheeler. The results are in good agreement with series expansions and experiments.
A wide low-mass binary model for the origin of axially symmetric non-thermal radio sources
International Nuclear Information System (INIS)
Kool, M. de; Heuvel, E.P.J. van den
1985-01-01
An accreting binary model has been proposed by recent workers to account for the origin of the axially symmetric non-thermal radio sources. The authors show that the only type of binary system that can produce the observed structural properties, is a relatively wide neutron star binary, in which the companion of the neutron star is a low-mass giant. Binaries of this type are expected to resemble closely the eight brightest galactic bulge X-ray sources as well as the progenitors of the two wide radio pulsar binaries. (U.K.)
Model for competitive binary and ternary ion-molecule reactions
International Nuclear Information System (INIS)
Herbst, E.
1985-01-01
A mechanism by which competitive binary and ternary ion-molecule reactions can occur is proposed. Calculations are undertaken for the specific system CH3(+) + NH3 + He which has been studied in the laboratory by Smith and Adams (1978), and the potential surface of which has been studied theoretically by Nobes and Radom (1983). It is shown that a potential-energy barrier in the exit channel prevents the rapid dissociation of collision complexes with large amounts of angular momentum and thereby allows collisional stabilization of the complexes. The calculated ternary-reaction rate coefficient is in good agreement with the experimental value, but a plot of the effective two-body rate coefficient of the ternary channel vs helium density does not quite show the observed saturation. 21 references
Modeling diffusion coefficients in binary mixtures of polar and non-polar compounds
DEFF Research Database (Denmark)
Medvedev, Oleg; Shapiro, Alexander
2005-01-01
The theory of transport coefficients in liquids, developed previously, is tested on a description of the diffusion coefficients in binary polar/non-polar mixtures, by applying advanced thermodynamic models. Comparison to a large set of experimental data shows good performance of the model. Only f...
Nuclear models relevant to evaluation
International Nuclear Information System (INIS)
Arthur, E.D.; Chadwick, M.B.; Hale, G.M.; Young, P.G.
1991-01-01
The widespread use of nuclear models continues in the creation of data evaluations. The reasons include extension of data evaluations to higher energies, creation of data libraries for isotopic components of natural materials, and production of evaluations for radiative target species. In these cases, experimental data are often sparse or nonexistent. As this trend continues, the nuclear models employed in evaluation work move towards more microscopically-based theoretical methods, prompted in part by the availability of increasingly powerful computational resources. Advances in nuclear models applicable to evaluation will be reviewed. These include advances in optical model theory, microscopic and phenomenological state and level density theory, unified models that consistently describe both equilibrium and nonequilibrium reaction mechanism, and improved methodologies for calculation of prompt radiation from fission. 84 refs., 8 figs
International Nuclear Information System (INIS)
Sun Zhongguo; Xi Guang; Chen Xi
2009-01-01
The binary collision of liquid droplets is of both practical importance and fundamental value in computational fluid mechanics. We present a modified surface tension model within the moving particle semi-implicit (MPS) method, and carry out two-dimensional simulations to investigate the mechanisms of coalescence and separation of the droplets during binary collision. The modified surface tension model improves accuracy and convergence. A mechanism map is established for various possible deformation pathways encountered during binary collision, as the impact speed is varied; a new pathway is reported when the collision speed is critical. In addition, eccentric collisions are simulated and the effect of the rotation of coalesced particle is explored. The results qualitatively agree with experiments and the numerical protocol may find applications in studying free surface flows and interface deformation
Interfacing modeling suite Physics Of Eclipsing Binaries 2.0 with a Virtual Reality Platform
Harriett, Edward; Conroy, Kyle; Prša, Andrej; Klassner, Frank
2018-01-01
To explore alternate methods for modeling eclipsing binary stars, we extrapolate upon PHOEBE’s (PHysics Of Eclipsing BinariEs) capabilities in a virtual reality (VR) environment to create an immersive and interactive experience for users. The application used is Vizard, a python-scripted VR development platform for environments such as Cave Automatic Virtual Environment (CAVE) and other off-the-shelf VR headsets. Vizard allows the freedom for all modeling to be precompiled without compromising functionality or usage on its part. The system requires five arguments to be precomputed using PHOEBE’s python front-end: the effective temperature, flux, relative intensity, vertex coordinates, and orbits; the user can opt to implement other features from PHOEBE to be accessed within the simulation as well. Here we present the method for making the data observables accessible in real time. An Occulus Rift will be available for a live showcase of various cases of VR rendering of PHOEBE binary systems including detached and contact binary stars.
Noll, K. S.
2017-12-01
The Jupiter Trojans, in the context of giant planet migration models, can be thought of as an extension of the small body populations found beyond Neptune in the Kuiper Belt. Binaries are a distinctive feature of small body populations in the Kuiper Belt with an especially high fraction apparent among the brightest Cold Classicals. The binary fraction, relative sizes, and separations in the dynamically excited populations (Scattered, Resonant) reflects processes that may have eroded a more abundant initial population. This trend continues in the Centaurs and Trojans where few binaries have been found. We review new evidence including a third resolved Trojan binary and lightcurve studies to understand how the Trojans are related to the small body populations that originated in the outer protoplanetary disk.
Hanni, Matti; Lantto, Perttu; Runeberg, Nino; Jokisaari, Jukka; Vaara, Juha
2004-09-22
Quantum chemical calculations of the nuclear shielding tensor, the nuclear quadrupole coupling tensor, and the spin-rotation tensor are reported for the Xe dimer using ab initio quantum chemical methods. The binary chemical shift delta, the anisotropy of the shielding tensor Delta sigma, the nuclear quadrupole coupling tensor component along the internuclear axis chi( parallel ), and the spin-rotation constant C( perpendicular ) are presented as a function of internuclear distance. The basis set superposition error is approximately corrected for by using the counterpoise correction (CP) method. Electron correlation effects are systematically studied via the Hartree-Fock, complete active space self-consistent field, second-order Møller-Plesset many-body perturbation, and coupled-cluster singles and doubles (CCSD) theories, the last one without and with noniterative triples, at the nonrelativistic all-electron level. We also report a high-quality theoretical interatomic potential for the Xe dimer, gained using the relativistic effective potential/core polarization potential scheme. These calculations used valence basis set of cc-pVQZ quality supplemented with a set of midbond functions. The second virial coefficient of Xe nuclear shielding, which is probably the experimentally best-characterized intermolecular interaction effect in nuclear magnetic resonance spectroscopy, is computed as a function of temperature, and compared to experiment and earlier theoretical results. The best results for the second virial coefficient, obtained using the CCSD(CP) binary chemical shift curve and either our best theoretical potential or the empirical potentials from the literature, are in good agreement with experiment. Zero-point vibrational corrections of delta, Delta sigma, chi (parallel), and C (perpendicular) in the nu=0, J=0 rovibrational ground state of the xenon dimer are also reported.
Energy Technology Data Exchange (ETDEWEB)
Awe, O.E., E-mail: draweoe2004@yahoo.com; Oshakuade, O.M.
2016-04-15
A new method for calculating Infinite Dilute Activity Coefficients (γ{sup ∞}s) of binary liquid alloys has been developed. This method is basically computing γ{sup ∞}s from experimental thermodynamic integral free energy of mixing data using Complex formation model. The new method was first used to theoretically compute the γ{sup ∞}s of 10 binary alloys whose γ{sup ∞}s have been determined by experiments. The significant agreement between the computed values and the available experimental values served as impetus for applying the new method to 22 selected binary liquid alloys whose γ{sup ∞}s are either nonexistent or incomplete. In order to verify the reliability of the computed γ{sup ∞}s of the 22 selected alloys, we recomputed the γ{sup ∞}s using three other existing methods of computing or estimating γ{sup ∞}s and then used the γ{sup ∞}s obtained from each of the four methods (the new method inclusive) to compute thermodynamic activities of components of each of the binary systems. The computed activities were compared with available experimental activities. It is observed that the results from the method being proposed, in most of the selected alloys, showed better agreement with experimental activity data. Thus, the new method is an alternative and in certain instances, more reliable approach of computing γ{sup ∞}s of binary liquid alloys.
International Nuclear Information System (INIS)
Nusbaumer, O. P. M.
2007-01-01
This study is concerned with the quantification of Probabilistic Risk Assessment (PRA) using linked Fault Tree (FT) models. Probabilistic Risk assessment (PRA) of Nuclear Power Plants (NPPs) complements traditional deterministic analysis; it is widely recognized as a comprehensive and structured approach to identify accident scenarios and to derive numerical estimates of the associated risk levels. PRA models as found in the nuclear industry have evolved rapidly. Increasingly, they have been broadly applied to support numerous applications on various operational and regulatory matters. Regulatory bodies in many countries require that a PRA be performed for licensing purposes. PRA has reached the point where it can considerably influence the design and operation of nuclear power plants. However, most of the tools available for quantifying large PRA models are unable to produce analytically correct results. The algorithms of such quantifiers are designed to neglect sequences when their likelihood decreases below a predefined cutoff limit. In addition, the rare event approximation (e.g. Moivre's equation) is typically implemented for the first order, ignoring the success paths and the possibility that two or more events can occur simultaneously. This is only justified in assessments where the probabilities of the basic events are low. When the events in question are failures, the first order rare event approximation is always conservative, resulting in wrong interpretation of risk importance measures. Advanced NPP PRA models typically include human errors, common cause failure groups, seismic and phenomenological basic events, where the failure probabilities may approach unity, leading to questionable results. It is accepted that current quantification tools have reached their limits, and that new quantification techniques should be investigated. A novel approach using the mathematical concept of Binary Decision Diagram (BDD) is proposed to overcome these deficiencies
Gao, Feng-Yin; Kang, Yan-Mei; Chen, Xi; Chen, Guanrong
2018-05-01
This paper reveals the effect of fractional Gaussian noise with Hurst exponent H ∈(1 /2 ,1 ) on the information capacity of a general nonlinear neuron model with binary signal input. The fGn and its corresponding fractional Brownian motion exhibit long-range, strong-dependent increments. It extends standard Brownian motion to many types of fractional processes found in nature, such as the synaptic noise. In the paper, for the subthreshold binary signal, sufficient conditions are given based on the "forbidden interval" theorem to guarantee the occurrence of stochastic resonance, while for the suprathreshold binary signal, the simulated results show that additive fGn with Hurst exponent H ∈(1 /2 ,1 ) could increase the mutual information or bits count. The investigation indicated that the synaptic noise with the characters of long-range dependence and self-similarity might be the driving factor for the efficient encoding and decoding of the nervous system.
Optimization of binary breeder reactor. 1. Sodium void reactivity and Doppler effect in a new model
International Nuclear Information System (INIS)
Nascimento, J.A. do; Dias, A.F.; Ishiguro, Y.
1985-01-01
A model for the Binary Breeder Reactor (BBR) is examined for the inherent safety characteristics, sodium void reactivity and Doppler effect in the beginning of cycle and a hypothetical end of cycle. In addition to the standard fueling mode of the BBR, two others are considered: U 238 /U 233 -alternate fueling, and U 238 /PU-normal fueling of LMFBRs. (Author) [pt
Theoretical model of the density of states of random binary alloys
International Nuclear Information System (INIS)
Zekri, N.; Brezini, A.
1991-09-01
A theoretical formulation of the density of states for random binary alloys is examined based on a mean field treatment. The present model includes both diagonal and off-diagonal disorder and also short-range order. Extensive results are reported for various concentrations and compared to other calculations. (author). 22 refs, 6 figs
Economic modeling using evolutionary algorithms : the effect of binary encoding of strategies
Waltman, L.R.; Eck, van N.J.; Dekker, Rommert; Kaymak, U.
2011-01-01
We are concerned with evolutionary algorithms that are employed for economic modeling purposes. We focus in particular on evolutionary algorithms that use a binary encoding of strategies. These algorithms, commonly referred to as genetic algorithms, are popular in agent-based computational economics
Soot modeling of counterflow diffusion flames of ethylene-based binary mixture fuels
Wang, Yu; Raj, Abhijeet Dhayal; Chung, Suk-Ho
2015-01-01
of ethylene and its binary mixtures with methane, ethane and propane based on the method of moments. The soot model has 36 soot nucleation reactions from 8 PAH molecules including pyrene and larger PAHs. Soot surface growth reactions were based on a modified
A Statistical Model for Misreported Binary Outcomes in Clustered RCTs of Education Interventions
Schochet, Peter Z.
2013-01-01
In education randomized control trials (RCTs), the misreporting of student outcome data could lead to biased estimates of average treatment effects (ATEs) and their standard errors. This article discusses a statistical model that adjusts for misreported binary outcomes for two-level, school-based RCTs, where it is assumed that misreporting could…
(Liquid plus liquid) equilibria of binary polymer solutions using a free-volume UNIQUAC-NRF model
DEFF Research Database (Denmark)
Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.
2006-01-01
+ liquid) equilibria (LLE) for a number of binary polymer solutions at various temperatures. The values for the binary characteristic energy parameters for the proposed model and the FV-UNIQUAC model along with their average relative deviations from the experimental data were reported. It should be stated...
Two-dimensional model of laser alloying of binary alloy powder with interval of melting temperature
Knyzeva, A. G.; Sharkeev, Yu. P.
2017-10-01
The paper contains two-dimensional model of laser beam melting of powders from binary alloy. The model takes into consideration the melting of alloy in some temperature interval between solidus and liquidus temperatures. The external source corresponds to laser beam with energy density distributed by Gauss law. The source moves along the treated surface according to given trajectory. The model allows investigating the temperature distribution and thickness of powder layer depending on technological parameters.
Functionally unidimensional item response models for multivariate binary data
DEFF Research Database (Denmark)
Ip, Edward; Molenberghs, Geert; Chen, Shyh-Huei
2013-01-01
The problem of fitting unidimensional item response models to potentially multidimensional data has been extensively studied. The focus of this article is on response data that have a strong dimension but also contain minor nuisance dimensions. Fitting a unidimensional model to such multidimensio......The problem of fitting unidimensional item response models to potentially multidimensional data has been extensively studied. The focus of this article is on response data that have a strong dimension but also contain minor nuisance dimensions. Fitting a unidimensional model...... to such multidimensional data is believed to result in ability estimates that represent a combination of the major and minor dimensions. We conjecture that the underlying dimension for the fitted unidimensional model, which we call the functional dimension, represents a nonlinear projection. In this article we investigate...... tool. An example regarding a construct of desire for physical competency is used to illustrate the functional unidimensional approach....
MESA models of the evolutionary state of the interacting binary epsilon Aurigae
Gibson, Justus L.; Stencel, Robert E.
2018-06-01
Using MESA code (Modules for Experiments in Stellar Astrophysics, version 9575), an evaluation was made of the evolutionary state of the epsilon Aurigae binary system (HD 31964, F0Iap + disc). We sought to satisfy several observational constraints: (1) requiring evolutionary tracks to pass close to the current temperature and luminosity of the primary star; (2) obtaining a period near the observed value of 27.1 years; (3) matching a mass function of 3.0; (4) concurrent Roche lobe overflow and mass transfer; (5) an isotopic ratio 12C/13C = 5 and, (6) matching the interferometrically determined angular diameter. A MESA model starting with binary masses of 9.85 + 4.5 M⊙, with a 100 d initial period, produces a 1.2 + 10.6 M⊙ result having a 547 d period, and a single digit 12C/13C ratio. These values were reached near an age of 20 Myr, when the donor star comes close to the observed luminosity and temperature for epsilon Aurigae A, as a post-RGB/pre-AGB star. Contemporaneously, the accretor then appears as an upper main-sequence, early B-type star. This benchmark model can provide a basis for further exploration of this interacting binary, and other long-period binary stars.
Primer on nuclear exchange models
Energy Technology Data Exchange (ETDEWEB)
Hafemeister, David [Physics Department, Cal Poly University, San Luis Obispo, California (United States)
2014-05-09
Basic physics is applied to nuclear force exchange models between two nations. Ultimately, this scenario approach can be used to try and answer the age old question of 'how much is enough?' This work is based on Chapter 2 of Physics of Societal Issues: Calculations on National Security, Environment and Energy (Springer, 2007 and 2014)
Efficient and robust estimation for longitudinal mixed models for binary data
DEFF Research Database (Denmark)
Holst, René
2009-01-01
This paper proposes a longitudinal mixed model for binary data. The model extends the classical Poisson trick, in which a binomial regression is fitted by switching to a Poisson framework. A recent estimating equations method for generalized linear longitudinal mixed models, called GEEP, is used...... as a vehicle for fitting the conditional Poisson regressions, given a latent process of serial correlated Tweedie variables. The regression parameters are estimated using a quasi-score method, whereas the dispersion and correlation parameters are estimated by use of bias-corrected Pearson-type estimating...... equations, using second moments only. Random effects are predicted by BLUPs. The method provides a computationally efficient and robust approach to the estimation of longitudinal clustered binary data and accommodates linear and non-linear models. A simulation study is used for validation and finally...
Weber, Juliane; Zachow, Christopher; Witthaut, Dirk
2018-03-01
Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.
Weber, Juliane; Zachow, Christopher; Witthaut, Dirk
2018-03-01
Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.
Frequency-domain reduced order models for gravitational waves from aligned-spin compact binaries
International Nuclear Information System (INIS)
Pürrer, Michael
2014-01-01
Black-hole binary coalescences are one of the most promising sources for the first detection of gravitational waves. Fast and accurate theoretical models of the gravitational radiation emitted from these coalescences are highly important for the detection and extraction of physical parameters. Spinning effective-one-body models for binaries with aligned-spins have been shown to be highly faithful, but are slow to generate and thus have not yet been used for parameter estimation (PE) studies. I provide a frequency-domain singular value decomposition-based surrogate reduced order model that is thousands of times faster for typical system masses and has a faithfulness mismatch of better than ∼0.1% with the original SEOBNRv1 model for advanced LIGO detectors. This model enables PE studies up to signal-to-noise ratios (SNRs) of 20 and even up to 50 for total masses below 50 M ⊙ . This paper discusses various choices for approximations and interpolation over the parameter space that can be made for reduced order models of spinning compact binaries, provides a detailed discussion of errors arising in the construction and assesses the fidelity of such models. (paper)
MESA models for the evolutionary status of the epsilon Aurigae disk-eclipsed binary system
Stencel, Robert E.; Gibson, Justus
2018-06-01
The brightest member of the class of disk-eclipsed binary stars is the Algol-like long-period binary, epsilon Aurigae (HD 31964, F0Iap + disk, http://adsabs.harvard.edu/abs/2016SPIE.9907E..17S ). Using MESA (Modules for Experiments in Stellar Astrophysics, version 9575), we have made an evaluation of its evolutionary state. We sought to satisfy several observational constraints, including: (1) requiring evolutionary tracks to pass close to the current temperature and luminosity of the primary star; (2) obtaining a period near the observed value of 27.1 years; (3) matching a mass function of 3.0; (4) concurrent Roche lobe overflow and mass transfer; (5) an isotopic ratio 12C / 13C = 5 and, (6) matching the interferometrically determined angular diameter. A MESA model starting with binary masses of 9.85 + 4.5 solar masses, with a 100 day initial period, produces a 1.2 + 10.6 solar masses result having a 547 day period, plus a single digit 12C / 13C ratio. These values were reached near an age of 20 Myr, when the donor star comes close to the observed luminosity and temperature for epsilon Aurigae A, as a post-RGB/pre-AGB star. Contemporaneously, the accretor then appears as an upper main sequence, early B-type star. This benchmark model can provide a basis for further exploration of this interacting binary, and other long period binary stars. This report has been submitted to MNRAS, along with a parallel investigation of mass transfer stream and disk sub-structure. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver.
AN X-RAY AND OPTICAL LIGHT CURVE MODEL OF THE ECLIPSING SYMBIOTIC BINARY SMC3
International Nuclear Information System (INIS)
Kato, Mariko; Hachisu, Izumi; Mikołajewska, Joanna
2013-01-01
Some binary evolution scenarios for Type Ia supernovae (SNe Ia) include long-period binaries that evolve to symbiotic supersoft X-ray sources in their late stage of evolution. However, symbiotic stars with steady hydrogen burning on the white dwarf's (WD) surface are very rare, and the X-ray characteristics are not well known. SMC3 is one such rare example and a key object for understanding the evolution of symbiotic stars to SNe Ia. SMC3 is an eclipsing symbiotic binary, consisting of a massive WD and red giant (RG), with an orbital period of 4.5 years in the Small Magellanic Cloud. The long-term V light curve variations are reproduced as orbital variations in the irradiated RG, whose atmosphere fills its Roche lobe, thus supporting the idea that the RG supplies matter to the WD at rates high enough to maintain steady hydrogen burning on the WD. We also present an eclipse model in which an X-ray-emitting region around the WD is almost totally occulted by the RG swelling over the Roche lobe on the trailing side, although it is always partly obscured by a long spiral tail of neutral hydrogen surrounding the binary in the orbital plane.
3D Modeling of Accretion Disks and Circumbinary Envelopes in Close Binaries
Bisikalo, D.
2010-12-01
A number of observations prove the complex flow structure in close binary stars. The gas dynamic structure of the flow is governed by the stream of matter from the inner Lagrange point, the accretion disk, the circum-disk halo, and the circumbinary envelope. Observations reflect the current state of a binary system and for their interpretation one should consider the gas dynamics of flow patterns. Three-dimensional numerical gasdynamical modeling is used to study the gaseous flow structure and dynamics in close binaries. It is shown that the periodic variations of the positions of the disk and the bow shock formed when the inner parts of the circumbinary envelope flow around the disk result in variations in both the rate of angular-momentum transfer to the disk and the flow structure near the Lagrange point L3. All these factors lead to periodic ejections of matter from the accretion disk and circum-disk halo into the outer layers of the circumbinary envelope. The results of simulations are used to estimate the physical parameters of the circumbinary envelope, including 3D matter distribution in it, and the matter-flow configuration and dynamics. The envelope becomes optically thick for systems with high mass-exchange rates, M⊙=10-8 Msun/year, and has a significant influence on the binary's observed features. The uneven phase distributions of the matter and density variations due to periodic injections of matter into the envelope are important for interpretations of observations of CBSs.
International Nuclear Information System (INIS)
Hills, J.G.
1975-01-01
We use analytic models to compute the evolution of the core of a stellar system due simultaneously to stellar evaporation which causes the system (core) to contract and to its binaries which cause it to expand by progressively decreasing its binding energy. The evolution of the system is determined by two parameters: the initial number of stars in the system N 0 , and the fraction f/subb/ of its stars which are binaries. For a fixed f/subb/, stellar evaporation initially dominates the dynamical evolution if N 0 is sufficiently large due to the fact that the rate of evaporation is determined chiefly by long-range encounters which increase in importance as the number of stars in the system increases. If stellar evaporation initially dominates, the system first contracts, but as N/subc/, the number of remaining stars in the system, decreases by evaporation, the system reaches a minimum radius and a maximum density and then it expands monotonically as N/subc/ decreases further. Open clusters expand monotonically from the beginning if they have anything approaching average Population I binary frequencies. Globular clusters are highly deficient in binaries in order to have formed and retained the high-density stellar cores observed in most of them. We estimate that for these system f/subb/ < or = 0.15
A Conditional Curie-Weiss Model for Stylized Multi-group Binary Choice with Social Interaction
Opoku, Alex Akwasi; Edusei, Kwame Owusu; Ansah, Richard Kwame
2018-04-01
This paper proposes a conditional Curie-Weiss model as a model for decision making in a stylized society made up of binary decision makers that face a particular dichotomous choice between two options. Following Brock and Durlauf (Discrete choice with social interaction I: theory, 1955), we set-up both socio-economic and statistical mechanical models for the choice problem. We point out when both the socio-economic and statistical mechanical models give rise to the same self-consistent equilibrium mean choice level(s). Phase diagram of the associated statistical mechanical model and its socio-economic implications are discussed.
Human modeling in nuclear engineering
International Nuclear Information System (INIS)
Yoshikawa, Hidekazu; Furuta, Kazuo.
1994-01-01
Review on progress of research and development on human modeling methods is made from the viewpoint of its importance on total man-machine system reliability surrounding nuclear power plant operation. Basic notions on three different approaches of human modeling (behavioristics, cognitives and sociologistics) are firstly introduced, followed by the explanation of fundamental scheme to understand human cognitives at man-machine interface and the mechanisms of human error and its classification. Then, general methodologies on human cognitive model by AI are explained with the brief summary of various R and D activities now prevailing in the human modeling communities around the world. A new method of dealing with group human reliability is also introduced which is based on sociologistic mathematical model. Lastly, problems on human model validation are discussed, followed by the introduction of new experimental method to estimate human cognitive state by psycho-physiological measurement, which is a new methodology plausible for human model validation. (author)
Observational constraints from models of close binary evolution
International Nuclear Information System (INIS)
Greve, J.P. de; Packet, W.
1984-01-01
The evolution of a system of 9 solar masses + 5.4 solar masses is computed from Zero Age Main Sequence through an early case B of mass exchange, up to the second phase of mass transfer after core helium burning. Both components are calculated simultaneously. The evolution is divided into several physically different phases. The characteristics of the models in each of these phases are transformed into corresponding 'observable' quantities. The outlook of the system for photometric observations is discussed, for an idealized case. The influence of the mass of the loser and the initial mass ratio is considered. (Auth.)
Binary collisions in popovici’s photogravitational model
Directory of Open Access Journals (Sweden)
Mioc V.
2002-01-01
Full Text Available The dynamics of bodies under the combined action of the gravitational attraction and the radiative repelling force has large and deep implications in astronomy. In the 1920s, the Romanian astronomer Constantin Popovici proposed a modified photogravitational law (considered by other scientists too. This paper deals with the collisions of the two-body problem associated with Popovici’s model. Resorting to McGehee-type transformations of the second kind, we obtain regular equations of motion and define the collision manifold. The flow on this boundary manifold is wholly described. This allows to point out some important qualitative features of the collisional motion: existence of the black-hole effect, gradientlikeness of the flow on the collision manifold, regularizability of collisions under certain conditions. Some questions, coming from the comparison of Levi-Civita’s regularizing transformations and McGehee’s ones, are formulated.
Structural models for amorphous transition metal binary alloys
International Nuclear Information System (INIS)
Ching, W.Y.; Lin, C.C.
1976-01-01
A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys
No tension between assembly models of super massive black hole binaries and pulsar observations.
Middleton, Hannah; Chen, Siyuan; Del Pozzo, Walter; Sesana, Alberto; Vecchio, Alberto
2018-02-08
Pulsar timing arrays are presently the only means to search for the gravitational wave stochastic background from super massive black hole binary populations, considered to be within the grasp of current or near-future observations. The stringent upper limit from the Parkes Pulsar Timing Array has been interpreted as excluding (>90% confidence) the current paradigm of binary assembly through galaxy mergers and hardening via stellar interaction, suggesting evolution is accelerated or stalled. Using Bayesian hierarchical modelling we consider implications of this upper limit for a range of astrophysical scenarios, without invoking stalling, nor more exotic physical processes. All scenarios are fully consistent with the upper limit, but (weak) bounds on population parameters can be inferred. Recent upward revisions of the black hole-galaxy bulge mass relation are disfavoured at 1.6σ against lighter models. Once sensitivity improves by an order of magnitude, a non-detection will disfavour the most optimistic scenarios at 3.9σ.
The use of continuous data versus binary data in MTC models: a case study in rheumatoid arthritis.
Schmitz, Susanne; Adams, Roisin; Walsh, Cathal
2012-11-06
Estimates of relative efficacy between alternative treatments are crucial for decision making in health care. When sufficient head to head evidence is not available Bayesian mixed treatment comparison models provide a powerful methodology to obtain such estimates. While models can be fit to a broad range of efficacy measures, this paper illustrates the advantages of using continuous outcome measures compared to binary outcome measures. Using a case study in rheumatoid arthritis a Bayesian mixed treatment comparison model is fit to estimate the relative efficacy of five anti-TNF agents currently licensed in Europe. The model is fit for the continuous HAQ improvement outcome measure and a binary version thereof as well as for the binary ACR response measure and the underlying continuous effect. Results are compared regarding their power to detect differences between treatments. Sixteen randomized controlled trials were included for the analysis. For both analyses, based on the HAQ improvement as well as based on the ACR response, differences between treatments detected by the binary outcome measures are subsets of the differences detected by the underlying continuous effects. The information lost when transforming continuous data into a binary response measure translates into a loss of power to detect differences between treatments in mixed treatment comparison models. Binary outcome measures are therefore less sensitive to change than continuous measures. Furthermore the choice of cut-off point to construct the binary measure also impacts the relative efficacy estimates.
The use of continuous data versus binary data in MTC models: A case study in rheumatoid arthritis
Directory of Open Access Journals (Sweden)
Schmitz Susanne
2012-11-01
Full Text Available Abstract Background Estimates of relative efficacy between alternative treatments are crucial for decision making in health care. When sufficient head to head evidence is not available Bayesian mixed treatment comparison models provide a powerful methodology to obtain such estimates. While models can be fit to a broad range of efficacy measures, this paper illustrates the advantages of using continuous outcome measures compared to binary outcome measures. Methods Using a case study in rheumatoid arthritis a Bayesian mixed treatment comparison model is fit to estimate the relative efficacy of five anti-TNF agents currently licensed in Europe. The model is fit for the continuous HAQ improvement outcome measure and a binary version thereof as well as for the binary ACR response measure and the underlying continuous effect. Results are compared regarding their power to detect differences between treatments. Results Sixteen randomized controlled trials were included for the analysis. For both analyses, based on the HAQ improvement as well as based on the ACR response, differences between treatments detected by the binary outcome measures are subsets of the differences detected by the underlying continuous effects. Conclusions The information lost when transforming continuous data into a binary response measure translates into a loss of power to detect differences between treatments in mixed treatment comparison models. Binary outcome measures are therefore less sensitive to change than continuous measures. Furthermore the choice of cut-off point to construct the binary measure also impacts the relative efficacy estimates.
A 3D dynamical model of the colliding winds in binary systems
Parkin, E. R.; Pittard, J. M.
2008-08-01
We present a three-dimensional (3D) dynamical model of the orbital-induced curvature of the wind-wind collision region in binary star systems. Momentum balance equations are used to determine the position and shape of the contact discontinuity between the stars, while further downstream the gas is assumed to behave ballistically. An Archimedean spiral structure is formed by the motion of the stars, with clear resemblance to high-resolution images of the so-called `pinwheel nebulae'. A key advantage of this approach over grid or smoothed particle hydrodynamic models is its significantly reduced computational cost, while it also allows the study of the structure obtained in an eccentric orbit. The model is relevant to symbiotic systems and γ-ray binaries, as well as systems with O-type and Wolf-Rayet stars. As an example application, we simulate the X-ray emission from hypothetical O+O and WR+O star binaries, and describe a method of ray tracing through the 3D spiral structure to account for absorption by the circumstellar material in the system. Such calculations may be easily adapted to study observations at wavelengths ranging from the radio to γ-ray.
Time variability of X-ray binaries: observations with INTEGRAL. Modeling
International Nuclear Information System (INIS)
Cabanac, Clement
2007-01-01
The exact origin of the observed X and Gamma ray variability in X-ray binaries is still an open debate in high energy astrophysics. Among others, these objects are showing aperiodic and quasi-periodic luminosity variations on timescales as small as the millisecond. This erratic behavior must put constraints on the proposed emission processes occurring in the vicinity of the neutrons star or the stellar mass black-hole held by these objects. We propose here to study their behavior following 3 different ways: first we examine the evolution of a particular X-ray source discovered by INTEGRAL, IGR J19140+0951. Using timing and spectral data given by different instruments, we show that the source type is plausibly consistent with a High Mass X-ray Binary hosting a neutrons star. Subsequently, we propose a new method dedicated to the study of timing data coming from coded mask aperture instruments. Using it on INTEGRAL/ISGRI real data, we detect the presence of periodic and quasi-periodic features in some pulsars and micro-quasars at energies as high as a hundred keV. Finally, we suggest a model designed to describe the low frequency variability of X-ray binaries in their hardest state. This model is based on thermal comptonization of soft photons by a warm corona in which a pressure wave is propagating in cylindrical geometry. By computing both numerical simulations and analytical solution, we show that this model should be suitable to describe some of the typical features observed in X-ray binaries power spectra in their hard state and their evolution such as aperiodic noise and low frequency quasi-periodic oscillations. (author) [fr
Measurement and modelling of hydrogen bonding in 1-alkanol plus n-alkane binary mixtures
DEFF Research Database (Denmark)
von Solms, Nicolas; Jensen, Lars; Kofod, Jonas L.
2007-01-01
Two equations of state (simplified PC-SAFT and CPA) are used to predict the monomer fraction of 1-alkanols in binary mixtures with n-alkanes. It is found that the choice of parameters and association schemes significantly affects the ability of a model to predict hydrogen bonding in mixtures, eve...... studies, which is clarified in the present work. New hydrogen bonding data based on infrared spectroscopy are reported for seven binary mixtures of alcohols and alkanes. (C) 2007 Elsevier B.V. All rights reserved....... though pure-component liquid densities and vapour pressures are predicted equally accurately for the associating compound. As was the case in the study of pure components, there exists some confusion in the literature about the correct interpretation and comparison of experimental data and theoretical...
Quantifying relative importance: Computing standardized effects in models with binary outcomes
Grace, James B.; Johnson, Darren; Lefcheck, Jonathan S.; Byrnes, Jarrett E.K.
2018-01-01
Scientists commonly ask questions about the relative importances of processes, and then turn to statistical models for answers. Standardized coefficients are typically used in such situations, with the goal being to compare effects on a common scale. Traditional approaches to obtaining standardized coefficients were developed with idealized Gaussian variables in mind. When responses are binary, complications arise that impact standardization methods. In this paper, we review, evaluate, and propose new methods for standardizing coefficients from models that contain binary outcomes. We first consider the interpretability of unstandardized coefficients and then examine two main approaches to standardization. One approach, which we refer to as the Latent-Theoretical or LT method, assumes that underlying binary observations there exists a latent, continuous propensity linearly related to the coefficients. A second approach, which we refer to as the Observed-Empirical or OE method, assumes responses are purely discrete and estimates error variance empirically via reference to a classical R2 estimator. We also evaluate the standard formula for calculating standardized coefficients based on standard deviations. Criticisms of this practice have been persistent, leading us to propose an alternative formula that is based on user-defined “relevant ranges”. Finally, we implement all of the above in an open-source package for the statistical software R.
Casero-Alonso, V; López-Fidalgo, J; Torsney, B
2017-01-01
Binary response models are used in many real applications. For these models the Fisher information matrix (FIM) is proportional to the FIM of a weighted simple linear regression model. The same is also true when the weight function has a finite integral. Thus, optimal designs for one binary model are also optimal for the corresponding weighted linear regression model. The main objective of this paper is to provide a tool for the construction of MV-optimal designs, minimizing the maximum of the variances of the estimates, for a general design space. MV-optimality is a potentially difficult criterion because of its nondifferentiability at equal variance designs. A methodology for obtaining MV-optimal designs where the design space is a compact interval [a, b] will be given for several standard weight functions. The methodology will allow us to build a user-friendly computer tool based on Mathematica to compute MV-optimal designs. Some illustrative examples will show a representation of MV-optimal designs in the Euclidean plane, taking a and b as the axes. The applet will be explained using two relevant models. In the first one the case of a weighted linear regression model is considered, where the weight function is directly chosen from a typical family. In the second example a binary response model is assumed, where the probability of the outcome is given by a typical probability distribution. Practitioners can use the provided applet to identify the solution and to know the exact support points and design weights. Copyright Â© 2016 Elsevier Ireland Ltd. All rights reserved.
Quasiparticle-phonon nuclear model
International Nuclear Information System (INIS)
Soloviev, V.G.
1977-01-01
The general assumptions of the quasiparticle-phonon model of complex nuclei are given. The choice of the model hamiltonian as an average field and residual forces is discussed. The phonon description and quasiparticle-phonon interaction are presented. The system of basic equations and their approximate solutions are obtained. The approximation is chosen so as to obtain the most correct description of few-quasiparticle components rather than of the whole wave function. The method of strenght functions is presented, which plays a decisive role in practical realization of the quasiparticle-phonon model for the description of some properties of complex nuclei. The range of applicability of the quasiparticle-phonon nuclear model is determined as few-quasiparticle components of the wave functions at low, intermediate and high excitation energies averaged in a certain energy interval
Meta-analysis of studies with bivariate binary outcomes: a marginal beta-binomial model approach.
Chen, Yong; Hong, Chuan; Ning, Yang; Su, Xiao
2016-01-15
When conducting a meta-analysis of studies with bivariate binary outcomes, challenges arise when the within-study correlation and between-study heterogeneity should be taken into account. In this paper, we propose a marginal beta-binomial model for the meta-analysis of studies with binary outcomes. This model is based on the composite likelihood approach and has several attractive features compared with the existing models such as bivariate generalized linear mixed model (Chu and Cole, 2006) and Sarmanov beta-binomial model (Chen et al., 2012). The advantages of the proposed marginal model include modeling the probabilities in the original scale, not requiring any transformation of probabilities or any link function, having closed-form expression of likelihood function, and no constraints on the correlation parameter. More importantly, because the marginal beta-binomial model is only based on the marginal distributions, it does not suffer from potential misspecification of the joint distribution of bivariate study-specific probabilities. Such misspecification is difficult to detect and can lead to biased inference using currents methods. We compare the performance of the marginal beta-binomial model with the bivariate generalized linear mixed model and the Sarmanov beta-binomial model by simulation studies. Interestingly, the results show that the marginal beta-binomial model performs better than the Sarmanov beta-binomial model, whether or not the true model is Sarmanov beta-binomial, and the marginal beta-binomial model is more robust than the bivariate generalized linear mixed model under model misspecifications. Two meta-analyses of diagnostic accuracy studies and a meta-analysis of case-control studies are conducted for illustration. Copyright © 2015 John Wiley & Sons, Ltd.
International Nuclear Information System (INIS)
Fang Zheng; Qiu Guanzhou
2007-01-01
A metallic solution model with adjustable parameter k has been developed to predict thermodynamic properties of ternary systems from those of its constituent three binaries. In the present model, the excess Gibbs free energy for a ternary mixture is expressed as a weighted probability sum of those of binaries and the k value is determined based on an assumption that the ternary interaction generally strengthens the mixing effects for metallic solutions with weak interaction, making the Gibbs free energy of mixing of the ternary system more negative than that before considering the interaction. This point is never considered in the models currently reported, where the only difference in a geometrical definition of molar values of components is considered that do not involve thermodynamic principles but are completely empirical. The current model describes the results of experiments very well, and by adjusting the k value also agrees with those from models used widely in the literature. Three ternary systems, Mg-Cu-Ni, Zn-In-Cd, and Cd-Bi-Pb are recalculated to demonstrate the method of determining k and the precision of the model. The results of the calculations, especially those in Mg-Cu-Ni system, are better than those predicted by the current models in the literature
Directory of Open Access Journals (Sweden)
Hiekata Takashi
2006-01-01
Full Text Available A new two-stage blind source separation (BSS method for convolutive mixtures of speech is proposed, in which a single-input multiple-output (SIMO-model-based independent component analysis (ICA and a new SIMO-model-based binary masking are combined. SIMO-model-based ICA enables us to separate the mixed signals, not into monaural source signals but into SIMO-model-based signals from independent sources in their original form at the microphones. Thus, the separated signals of SIMO-model-based ICA can maintain the spatial qualities of each sound source. Owing to this attractive property, our novel SIMO-model-based binary masking can be applied to efficiently remove the residual interference components after SIMO-model-based ICA. The experimental results reveal that the separation performance can be considerably improved by the proposed method compared with that achieved by conventional BSS methods. In addition, the real-time implementation of the proposed BSS is illustrated.
New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions
Energy Technology Data Exchange (ETDEWEB)
Liu, Chang [College of Environmental Science and Engineering, Anhui Normal University, South Jiuhua Road, 189, 241002 Wuhu (China); Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Fiol, Núria [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Villaescusa, Isabel, E-mail: Isabel.Villaescusa@udg.edu [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Poch, Jordi [Applied Mathematics Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain)
2016-01-15
In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data.
New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions
International Nuclear Information System (INIS)
Liu, Chang; Fiol, Núria; Villaescusa, Isabel; Poch, Jordi
2016-01-01
In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data
Hadronic model for the non-thermal radiation from the binary system AR Scorpii
Bednarek, W.
2018-05-01
AR Scorpii is a close binary system containing a rotation powered white dwarf and a low-mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure hadronic models for the high energy non-thermal processes in this binary system. Relativistic electrons and hadrons are assumed to be accelerated in a strongly magnetised, turbulent region formed in collision of a rotating white dwarf magnetosphere and a magnetosphere/dense atmosphere of the M-dwarf star. We propose that the non-thermal X-ray emission is produced either by the primary electrons or the secondary e± pairs from decay of charged pions created in collisions of hadrons with the companion star atmosphere. We show that the accompanying γ-ray emission from decay of neutral pions, which are produced by these same protons, is expected to be on the detectability level of the present and/or the future satellite and Cherenkov telescopes. The γ-ray observations of the binary system AR Sco should allow us to constrain the efficiency of hadron and electron acceleration and also the details of the radiation processes.
Comparison of many bodied and binary collision cascade models up to 1 keV
International Nuclear Information System (INIS)
Schwartz, D.M.; Schiffgens, J.D.; Doran, D.G.; Odette, G.R.; Ariyasu, R.G.
1976-01-01
A quasi-dynamical code ADDES has been developed to model displacement cascades in copper for primary knockon atom energies up to several keV. ADDES is like a dynamical code in that it employs a many body treatment, yet similar to a binary collision code in that it incorporates the basic assumption that energy transfers below several eV can be ignored in describing cascade evolution. This paper is primarily concerned with (1) a continuing effort to validate the assumptions and specific parameters in the code by the comparison of ADDES results with experiment and with results from a dynamical code, and (2) comparisons of ADDES results with those from a binary collision code. The directional dependence of the displacement threshold is in reasonable agreement with the measurements of Jung et al. The behavior of focused replacement sequences is very similar to that obtained with the dynamical codes GRAPE and COMENT. Qualitative agreement was found between ADDES and COMENT for a higher energy (500 eV) defocused event while differences, still under study, are apparent in a 250 eV high index event. Comparisons of ADDES with the binary collision code MARLOWE show surprisingly good agreement in the 250 to 1000 eV range for both number and separation of Frenkel pairs. A preliminary observation, perhaps significant to displacement calculations utilizing the concept of a mean displacement energy, is the dissipation of 300 to 400 eV in a replacement sequence producing a single interstitial
The nuclear single particle model
International Nuclear Information System (INIS)
Mang, H.
1985-01-01
Twenty years ago in December 1963 one half of the Nobel prize in Physics was awarded to Maria Goeppert-Mayer and Johannes Daniel Jensen for their work on the nuclear shell model. They suggested independently that a strong spin-orbit force with the opposite sign of the one known from atomic physics should be added to the shell-model potential. This proved to be the crucial new idea, because then all the bits of and pieces of evidence that had accumulated over the years fell into place. The author begins with the basic assumption: In a nucleus nucleons move almost independently of each other in an average or shell-model potential. He then provides experimental evidence plausibility arguments and mathematical deductions
An odor interaction model of binary odorant mixtures by a partial differential equation method.
Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong
2014-07-09
A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.
Reconstruction of binary geological images using analytical edge and object models
Abdollahifard, Mohammad J.; Ahmadi, Sadegh
2016-04-01
Reconstruction of fields using partial measurements is of vital importance in different applications in geosciences. Solving such an ill-posed problem requires a well-chosen model. In recent years, training images (TI) are widely employed as strong prior models for solving these problems. However, in the absence of enough evidence it is difficult to find an adequate TI which is capable of describing the field behavior properly. In this paper a very simple and general model is introduced which is applicable to a fairly wide range of binary images without any modifications. The model is motivated by the fact that nearly all binary images are composed of simple linear edges in micro-scale. The analytic essence of this model allows us to formulate the template matching problem as a convex optimization problem having efficient and fast solutions. The model has the potential to incorporate the qualitative and quantitative information provided by geologists. The image reconstruction problem is also formulated as an optimization problem and solved using an iterative greedy approach. The proposed method is capable of recovering the image unknown values with accuracies about 90% given samples representing as few as 2% of the original image.
An Odor Interaction Model of Binary Odorant Mixtures by a Partial Differential Equation Method
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Luchun Yan
2014-07-01
Full Text Available A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE method. Based on the measurement method (tangent-intercept method of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture’s odor intensity to the individual odorant’s relative odor activity value (OAV. Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.
Blackman, Jonathan; Field, Scott E; Galley, Chad R; Szilágyi, Béla; Scheel, Mark A; Tiglio, Manuel; Hemberger, Daniel A
2015-09-18
Simulating a binary black hole coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. Using reduced order modeling techniques, we construct an accurate surrogate model, which is evaluated in a millisecond to a second, for numerical relativity (NR) waveforms from nonspinning binary black hole coalescences with mass ratios in [1, 10] and durations corresponding to about 15 orbits before merger. We assess the model's uncertainty and show that our modeling strategy predicts NR waveforms not used for the surrogate's training with errors nearly as small as the numerical error of the NR code. Our model includes all spherical-harmonic _{-2}Y_{ℓm} waveform modes resolved by the NR code up to ℓ=8. We compare our surrogate model to effective one body waveforms from 50M_{⊙} to 300M_{⊙} for advanced LIGO detectors and find that the surrogate is always more faithful (by at least an order of magnitude in most cases).
MODELLING OF NUCLEAR FUEL CLADDING TUBES CORROSION
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Miroslav Cech
2016-12-01
Full Text Available This paper describes materials made of zirconium-based alloys used for nuclear fuel cladding fabrication. It is focused on corrosion problems their theoretical description and modeling in nuclear engineering.
Nuclear fuel cycle modelling using MESSAGE
International Nuclear Information System (INIS)
Guiying Zhang; Dongsheng Niu; Guoliang Xu; Hui Zhang; Jue Li; Lei Cao; Zeqin Guo; Zhichao Wang; Yutong Qiu; Yanming Shi; Gaoliang Li
2017-01-01
In order to demonstrate the possibilities of application of MESSAGE tool for the modelling of a Nuclear Energy System at the national level, one of the possible open nuclear fuel cycle options based on thermal reactors has been modelled using MESSAGE. The steps of the front-end and back-end of nuclear fuel cycle and nuclear reactor operation are described. The optimal structure for Nuclear Power Development and optimal schedule for introducing various reactor technologies and fuel cycle options; infrastructure facilities, nuclear material flows and waste, investments and other costs are demonstrated. (author)
Theoretical Models of Protostellar Binary and Multiple Systems with AMR Simulations
Matsumoto, Tomoaki; Tokuda, Kazuki; Onishi, Toshikazu; Inutsuka, Shu-ichiro; Saigo, Kazuya; Takakuwa, Shigehisa
2017-05-01
We present theoretical models for protostellar binary and multiple systems based on the high-resolution numerical simulation with an adaptive mesh refinement (AMR) code, SFUMATO. The recent ALMA observations have revealed early phases of the binary and multiple star formation with high spatial resolutions. These observations should be compared with theoretical models with high spatial resolutions. We present two theoretical models for (1) a high density molecular cloud core, MC27/L1521F, and (2) a protobinary system, L1551 NE. For the model for MC27, we performed numerical simulations for gravitational collapse of a turbulent cloud core. The cloud core exhibits fragmentation during the collapse, and dynamical interaction between the fragments produces an arc-like structure, which is one of the prominent structures observed by ALMA. For the model for L1551 NE, we performed numerical simulations of gas accretion onto protobinary. The simulations exhibit asymmetry of a circumbinary disk. Such asymmetry has been also observed by ALMA in the circumbinary disk of L1551 NE.
Bain, Peter A; Kumar, Anu
2018-05-01
The widespread use of hydraulic fracturing (HF) in oil and gas extraction operations has led to concern over environmental risks posed by chemicals used in HF fluids. Here we employed a suite of stable luciferase reporter gene assays to investigate the potential for selected HF chemicals or geogenics to activate or antagonise nuclear receptor signalling. We screened three biocides (bronopol [BP], glutaraldehyde [GA], and tetrakis(hydroxymethyl)phosphonium sulfate [THPS]), a surfactant (2-butoxyethanol), a friction reducer (polyacrylamide), and a coal seam geogenic (o-cresol) for their potential to act as agonists or antagonists of the estrogen receptor, androgen receptor, progesterone receptor (PR), glucocorticoid receptor or peroxisome proliferator-activated receptor gamma (PPARγ). None of the chemicals induced luciferase activity in any of assays used in the study. In antagonistic mode, BP, GA and THPS caused reductions in luciferase activity in the reporter assays at higher concentrations (50-100 μM), while at low concentrations (2-10 μM) GA and THPS enhanced luciferase activity in some assays relative to controls. None of the other tested chemicals exhibited antagonism in the selected assays. In most cases, altered receptor signalling only occurred at concentrations exhibiting cytotoxicity. However, PPARγ activity, and to a lesser extent PR activity, were inhibited by THPS at sub-cytotoxic concentrations. The majority of binary combinations tested exhibited significantly less-than-additive cytotoxicity, and none of the combinations exhibited synergistic cytotoxicity. In summary, the results of the present study indicate that the selected chemicals are not likely to function as direct agonists of the nuclear receptors tested, and only one chemical, THPS was an apparent partial antagonist of two nuclear receptors. Copyright © 2017. Published by Elsevier Ltd.
New limb-darkening coefficients for modeling binary star light curves
Van Hamme, W.
1993-01-01
We present monochromatic, passband-specific, and bolometric limb-darkening coefficients for a linear as well as nonlinear logarithmic and square root limb-darkening laws. These coefficients, including the bolometric ones, are needed when modeling binary star light curves with the latest version of the Wilson-Devinney light curve progam. We base our calculations on the most recent ATLAS stellar atmosphere models for solar chemical composition stars with a wide range of effective temperatures and surface gravitites. We examine how well various limb-darkening approximations represent the variation of the emerging specific intensity across a stellar surface as computed according to the model. For binary star light curve modeling purposes, we propose the use of a logarithmic or a square root law. We design our tables in such a manner that the relative quality of either law with respect to another can be easily compared. Since the computation of bolometric limb-darkening coefficients first requires monochromatic coefficients, we also offer tables of these coefficients (at 1221 wavelength values between 9.09 nm and 160 micrometer) and tables of passband-specific coefficients for commonly used photometric filters.
International Nuclear Information System (INIS)
Hoh, Y.C.
1977-03-01
Chemically based thermodynamic models to predict the distribution coefficients and the separation factors for the liquid--liquid extraction of lanthanides-organophosphorus compounds were developed by assuming that the quotient of the activity coefficients of each species varies slightly with its concentrations, by using aqueous lanthanide or actinide complexes stoichiometric stability constants expressed as its degrees of formation, by making use of the extraction mechanism and the equilibrium constant for the extraction reaction. For a single component system, the thermodynamic model equations which predict the distribution coefficients, are dependent on the free organic concentration, the equilibrated ligand and hydrogen ion concentrations, the degree of formation, and on the extraction mechanism. For a binary component system, the thermodynamic model equation which predicts the separation factors is the same for all cases. This model equation is dependent on the degrees of formation of each species in their binary system and can be used in a ternary component system to predict the separation factors for the solutes relative to each other
Goal-oriented error estimation for Cahn-Hilliard models of binary phase transition
van der Zee, Kristoffer G.
2010-10-27
A posteriori estimates of errors in quantities of interest are developed for the nonlinear system of evolution equations embodied in the Cahn-Hilliard model of binary phase transition. These involve the analysis of wellposedness of dual backward-in-time problems and the calculation of residuals. Mixed finite element approximations are developed and used to deliver numerical solutions of representative problems in one- and two-dimensional domains. Estimated errors are shown to be quite accurate in these numerical examples. © 2010 Wiley Periodicals, Inc.
The potential energy landscape in the Lennard-Jones binary mixture model
International Nuclear Information System (INIS)
Sampoli, M; Benassi, P; Eramo, R; Angelani, L; Ruocco, G
2003-01-01
The potential energy landscape in the Kob-Andersen Lennard-Jones binary mixture model has been studied carefully from the liquid down to the supercooled regime, from T = 2 down to 0.46. One thousand independent configurations along the time evolution locus have been examined at each temperature investigated. From the starting configuration, we searched for the nearest saddle (or quasi-saddle) and minimum of the potential energy. The vibrational densities of states for the starting and the two derived configurations have been evaluated. Besides the number of negative eigenvalues of the saddles other quantities show some signature of the approach of the dynamical arrest temperature
Directory of Open Access Journals (Sweden)
Seong Hee Choea
1992-06-01
Full Text Available The reflection effect on three types of eclipsing binaries has been analyzed Wilson and Devinney's model and Russell and Merrill's model. The reflection effect was displayed on the theoretical light curves for the various conditions using the Wilson and Devinney's light curve program. Two models were compared after the rectifing the theoretical light curves including the reflection effect with the Russell and Merrill's method. The result shows that two models have an agreement on the reflection effect just in cases of the small difference in temperature and albedo between two stars in the system.
Modeling the rate of HIV testing from repeated binary data amidst potential never-testers.
Rice, John D; Johnson, Brent A; Strawderman, Robert L
2018-01-04
Many longitudinal studies with a binary outcome measure involve a fraction of subjects with a homogeneous response profile. In our motivating data set, a study on the rate of human immunodeficiency virus (HIV) self-testing in a population of men who have sex with men (MSM), a substantial proportion of the subjects did not self-test during the follow-up study. The observed data in this context consist of a binary sequence for each subject indicating whether or not that subject experienced any events between consecutive observation time points, so subjects who never self-tested were observed to have a response vector consisting entirely of zeros. Conventional longitudinal analysis is not equipped to handle questions regarding the rate of events (as opposed to the odds, as in the classical logistic regression model). With the exception of discrete mixture models, such methods are also not equipped to handle settings in which there may exist a group of subjects for whom no events will ever occur, i.e. a so-called "never-responder" group. In this article, we model the observed data assuming that events occur according to some unobserved continuous-time stochastic process. In particular, we consider the underlying subject-specific processes to be Poisson conditional on some unobserved frailty, leading to a natural focus on modeling event rates. Specifically, we propose to use the power variance function (PVF) family of frailty distributions, which contains both the gamma and inverse Gaussian distributions as special cases and allows for the existence of a class of subjects having zero frailty. We generalize a computational algorithm developed for a log-gamma random intercept model (Conaway, 1990. A random effects model for binary data. Biometrics46, 317-328) to compute the exact marginal likelihood, which is then maximized to obtain estimates of model parameters. We conduct simulation studies, exploring the performance of the proposed method in comparison with
International Nuclear Information System (INIS)
Mathews, G.J.; Wilson, J.R.; Evans, C.R.; Detweiler, S.L.
1987-12-01
The dynamics of the final stages of the coalescence of two neturon stars (such as the binary pulsar PSR 1913+16) is an unsolved problem in astrophysics. Such systems are probably efficient generators of gravitational radiation, and may be significant contributors to heavy-element nucleosynthesis. The input physics for the study of such systems is similar to that required for the strudy of heavy-ion collision hydrodynamics; e.g., a finite temperature nuclear equation of state, properties of nuclei away from stability, etc. We discuss the development of a relativistic hydrodynamics code in three spatial dimensions for the purpose of studying such neutron-star systems. The properties of the mass-radius relation (determined by the nuclear equation of state) may lead to a proposed mechanism by which hot, highly neutronized matter is ejected from the coalescing stars. This material is photodisintegrated into a free (mostly) neutron gas which may subsequently experience rapid-neutron capture (r-process) nucleosynthesis. 15 refs., 4 figs
International Nuclear Information System (INIS)
Ramirez-Ruiz, Enrico; MacLeod, Morgan; Trenti, Michele; Roberts, Luke F.; Lee, William H.; Saladino-Rosas, Martha I.
2015-01-01
Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that lived and died before them. The presence of r-process elements in a handful of carbon-enhanced metal-poor (CEMP-r) stars, which are assumed to be closely connected to the chemical yield from the first stars, is hard to reconcile with standard neutron star mergers. Here we show that the production rate of dynamically assembled compact binaries in high-z nuclear star clusters can attain a sufficient high value to be a potential viable source of heavy r-process material in CEMP-r stars. The predicted frequency of such events in the early Galaxy, much lower than the frequency of Type II supernovae but with significantly higher mass ejected per event, can naturally lead to a high level of scatter of Eu as observed in CEMP-r stars
Energy Technology Data Exchange (ETDEWEB)
Ramirez-Ruiz, Enrico; MacLeod, Morgan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Trenti, Michele [Kavli Institute for Cosmology and Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Roberts, Luke F. [TAPIR, California Institute of Technology, Pasadena, California 91125 (United States); Lee, William H.; Saladino-Rosas, Martha I. [Instituto de Astronomía, Universidad Nacional Autónoma de México, México DF 04510, México (Mexico)
2015-04-01
Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that lived and died before them. The presence of r-process elements in a handful of carbon-enhanced metal-poor (CEMP-r) stars, which are assumed to be closely connected to the chemical yield from the first stars, is hard to reconcile with standard neutron star mergers. Here we show that the production rate of dynamically assembled compact binaries in high-z nuclear star clusters can attain a sufficient high value to be a potential viable source of heavy r-process material in CEMP-r stars. The predicted frequency of such events in the early Galaxy, much lower than the frequency of Type II supernovae but with significantly higher mass ejected per event, can naturally lead to a high level of scatter of Eu as observed in CEMP-r stars.
Discussions on the non-equilibrium effects in the quantitative phase field model of binary alloys
International Nuclear Information System (INIS)
Zhi-Jun, Wang; Jin-Cheng, Wang; Gen-Cang, Yang
2010-01-01
All the quantitative phase field models try to get rid of the artificial factors of solutal drag, interface diffusion and interface stretch in the diffuse interface. These artificial non-equilibrium effects due to the introducing of diffuse interface are analysed based on the thermodynamic status across the diffuse interface in the quantitative phase field model of binary alloys. Results indicate that the non-equilibrium effects are related to the negative driving force in the local region of solid side across the diffuse interface. The negative driving force results from the fact that the phase field model is derived from equilibrium condition but used to simulate the non-equilibrium solidification process. The interface thickness dependence of the non-equilibrium effects and its restriction on the large scale simulation are also discussed. (cross-disciplinary physics and related areas of science and technology)
International Nuclear Information System (INIS)
Eggleton, P.P.; Pringle, J.E.
1985-01-01
This volume contains 15 review articles in the field of binary stars. The subjects reviewed span considerably, from the shortest period of interacting binaries to the longest, symbiotic stars. Also included are articles on Algols, X-ray binaries and Wolf-Rayet stars (single and binary). Contents: Preface. List of Participants. Activity of Contact Binary Systems. Wolf-Rayet Stars and Binarity. Symbiotic Stars. Massive X-ray Binaries. Stars that go Hump in the Night: The SU UMa Stars. Interacting Binaries - Summing Up
International Nuclear Information System (INIS)
Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J.; Mosser, B.; Guzik, J. A.
2013-01-01
Red giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, binaries provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in eclipsing binary systems is therefore an important goal that could potentially offer very robust characterization of these systems. Until recently, only one case has been discovered with Kepler. We cross-correlate the detected red giant and eclipsing-binary catalogs from Kepler data to find possible candidate systems. Light-curve modeling and mean properties measured from asteroseismology are combined to yield specific measurements of periods, masses, radii, temperatures, eclipse timing variations, core rotation rates, and red giant evolutionary state. After using three different techniques to eliminate false positives, out of the 70 systems common to the red giant and eclipsing-binary catalogs we find 13 strong candidates (12 previously unknown) to be eclipsing binaries, one to be a non-eclipsing binary with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. The systems span a range of orbital eccentricities, periods, and spectral types F, G, K, and M for the companion of the red giant. One case even suggests an eclipsing binary composed of two red giant stars and another of a red giant with a δ-Scuti star. The discovery of multiple pulsating red giants in eclipsing binaries provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many of the
Modeling and analysis of periodic orbits around a contact binary asteroid
Feng, Jinglang; Noomen, Ron; Visser, Pieter N. A. M.; Yuan, Jianping
2015-06-01
The existence and characteristics of periodic orbits (POs) in the vicinity of a contact binary asteroid are investigated with an averaged spherical harmonics model. A contact binary asteroid consists of two components connected to each other, resulting in a highly bifurcated shape. Here, it is represented by a combination of an ellipsoid and a sphere. The gravitational field of this configuration is for the first time expanded into a spherical harmonics model up to degree and order 8. Compared with the exact potential, the truncation at degree and order 4 is found to introduce an error of less than 10 % at the circumscribing sphere and less than 1 % at a distance of the double of the reference radius. The Hamiltonian taking into account harmonics up to degree and order 4 is developed. After double averaging of this Hamiltonian, the model is reduced to include zonal harmonics only and frozen orbits are obtained. The tesseral terms are found to introduce significant variations on the frozen orbits and distort the frozen situation. Applying the method of Poincaré sections, phase space structures of the single-averaged model are generated for different energy levels and rotation rates of the asteroid, from which the dynamics driven by the 4×4 harmonics model is identified and POs are found. It is found that the disturbing effect of the highly irregular gravitational field on orbital motion is weakened around the polar region, and also for an asteroid with a fast rotation rate. Starting with initial conditions from this averaged model, families of exact POs in the original non-averaged system are obtained employing a numerical search method and a continuation technique. Some of these POs are stable and are candidates for future missions.
Nuclear Physical Uncertainties in Modeling X-Ray Bursts
Regis, Eric; Amthor, A. Matthew
2017-09-01
Type I x-ray bursts occur when a neutron star accretes material from the surface of another star in a compact binary star system. For certain accretion rates and material compositions, much of the nuclear material is burned in short, explosive bursts. Using a one-dimensional stellar model, Kepler, and a comprehensive nuclear reaction rate library, ReacLib, we have simulated chains of type I x-ray bursts. Unfortunately, there are large remaining uncertainties in the nuclear reaction rates involved, since many of the isotopes reacting are unstable and have not yet been studied experimentally. Some individual reactions, when varied within their estimated uncertainty, alter the light curves dramatically. This limits our ability to understand the structure of the neutron star. Previous studies have looked at the effects of individual reaction rate uncertainties. We have applied a Monte Carlo method ``-simultaneously varying a set of reaction rates'' -in order to probe the expected uncertainty in x-ray burst behaviour due to the total uncertainty in all nuclear reaction rates. Furthermore, we aim to discover any nonlinear effects due to the coupling between different reaction rates. Early results show clear non-linear effects. This research was made possible by NSF-DUE Grant 1317446, BUScholars Program.
Tay, Richard
2016-03-01
The binary logistic model has been extensively used to analyze traffic collision and injury data where the outcome of interest has two categories. However, the assumption of a symmetric distribution may not be a desirable property in some cases, especially when there is a significant imbalance in the two categories of outcome. This study compares the standard binary logistic model with the skewed logistic model in two cases in which the symmetry assumption is violated in one but not the other case. The differences in the estimates, and thus the marginal effects obtained, are significant when the assumption of symmetry is violated. Copyright © 2015 Elsevier Ltd. All rights reserved.
Critical assessment of nuclear mass models
International Nuclear Information System (INIS)
Moeller, P.; Nix, J.R.
1992-01-01
Some of the physical assumptions underlying various nuclear mass models are discussed. The ability of different mass models to predict new masses that were not taken into account when the models were formulated and their parameters determined is analyzed. The models are also compared with respect to their ability to describe nuclear-structure properties in general. The analysis suggests future directions for mass-model development
Eckersall, A. J.; Vaughan, S.; Wynn, G. A.
2017-10-01
All observations of Galactic X-ray binaries are affected by absorption from gas and dust in the interstellar medium (ISM) which imprints narrow (line) and broad (photoelectric edges) features on the continuum emission spectrum of the binary. Any spectral model used to fit data from a Galactic X-ray binary must therefore take account of these features; when the absorption is strong (as for most Galactic sources) it becomes important to accurately model the ISM absorption in order to obtain unbiased estimates of the parameters of the (emission) spectrum of the binary system. In this paper, we present analysis of some of the best spectroscopic data from the XMM-Newton RGS instrument using the most up-to-date photoabsorption model of the gaseous ISM ISMabs. We calculate column densities for H, O, Ne and Fe for seven transient black hole X-ray binary systems. We find that the hydrogen column densities in particular can vary greatly from those presented elsewhere in the literature. We assess the impact of using inaccurate column densities and older X-ray absorption models on spectral analysis using simulated data. We find that poor treatment of absorption can lead to large biases in inferred disc properties and that an independent analysis of absorption parameters can be used to alleviate such issues.
Bayesian binary regression model: an application to in-hospital death after AMI prediction
Directory of Open Access Journals (Sweden)
Aparecida D. P. Souza
2004-08-01
Full Text Available A Bayesian binary regression model is developed to predict death of patients after acute myocardial infarction (AMI. Markov Chain Monte Carlo (MCMC methods are used to make inference and to evaluate Bayesian binary regression models. A model building strategy based on Bayes factor is proposed and aspects of model validation are extensively discussed in the paper, including the posterior distribution for the c-index and the analysis of residuals. Risk assessment, based on variables easily available within minutes of the patients' arrival at the hospital, is very important to decide the course of the treatment. The identified model reveals itself strongly reliable and accurate, with a rate of correct classification of 88% and a concordance index of 83%.Um modelo bayesiano de regressão binária é desenvolvido para predizer óbito hospitalar em pacientes acometidos por infarto agudo do miocárdio. Métodos de Monte Carlo via Cadeias de Markov (MCMC são usados para fazer inferência e validação. Uma estratégia para construção de modelos, baseada no uso do fator de Bayes, é proposta e aspectos de validação são extensivamente discutidos neste artigo, incluindo a distribuição a posteriori para o índice de concordância e análise de resíduos. A determinação de fatores de risco, baseados em variáveis disponíveis na chegada do paciente ao hospital, é muito importante para a tomada de decisão sobre o curso do tratamento. O modelo identificado se revela fortemente confiável e acurado, com uma taxa de classificação correta de 88% e um índice de concordância de 83%.
Wulandari, S. P.; Salamah, M.; Rositawati, A. F. D.
2018-04-01
Food security is the condition where the food fulfilment is managed well for the country till the individual. Indonesia is one of the country which has the commitment to create the food security becomes main priority. However, the food necessity becomes common thing means that it doesn’t care about nutrient standard and the health condition of family member, so in the fulfilment of food necessity also has to consider the disease suffered by the family member, one of them is pulmonary tuberculosa. From that reasons, this research is conducted to know the factors which influence on household food security status which suffered from pulmonary tuberculosis in the coastal area of Surabaya by using binary logistic regression method. The analysis result by using binary logistic regression shows that the variables wife latest education, house density and spacious house ventilation significantly affect on household food security status which suffered from pulmonary tuberculosis in the coastal area of Surabaya, where the wife education level is University/equivalent, the house density is eligible or 8 m2/person and spacious house ventilation 10% of the floor area has the opportunity to become food secure households amounted to 0.911089. While the chance of becoming food insecure households amounted to 0.088911. The model household food security status which suffered from pulmonary tuberculosis in the coastal area of Surabaya has been conformable, and the overall percentages of those classifications are at 71.8%.
Fundamentals of nuclear science and engineering
Shultis, J Kenneth
2007-01-01
FUNDAMENTAL CONCEPTS Modern Units The Atom Chart of Nuclides MODERN PHYSICS CONCEPTS The Special Theory of Relativity Radiation as Waves and Particles Quantum Mechanics Derivation of Some Special Relativity Results Solutions to Schrodinger's Wave Equation ATOMIC/NUCLEAR MODELS Development of the Modern Atom Model Models of the Nucleus NUCLEAR ENERGETICS Binding Energy Nucleon Separation Energy Nuclear Reactions Examples of Binary Nuclear Reactions Q-Value for a Reaction Conservation of Charge and the Calculation of Q-values Q-Value for reactions Producing Excited Nuclei RADIOACTIVITY Overview Types of Radioactive Decay Radioactive Decay Diagrams Energetics of Radioactive Decay Characteristics of Radioactive Decay Decay Dynamics Naturally Occurring Radionuclides Radiodating Radioactive Decay Data BINARY NUCLEAR REACTIONS Types of Binary Reactions Kinematics of Binary Two-Product Nuclear Reactions Reaction Threshold Energy Applications of Binary Kinematics Reactions...
Three-particle forces and nuclear models
International Nuclear Information System (INIS)
Krutov, V.A.
1980-01-01
Different nuclear models accounting and unaccounting for three-particle internucleon forces (TIF) are reviewed. At present only two nuclear models use manifestly TIP: the Vautherin-Brink-Skyrme (VBS) model and the model proposed by the author of the review and called the semiphenomenological (SP) nuclear model. There is a short discussion of major drawbacks of models unaccounting for TIF: multiparticle shell model, ''superfluid model'', Harty-Fock calculations with two-particle forces, Bruckner-Hartry-Fock calculations, the relativistic self-consistent nuclear model. The VBS and SP models are discussed in detail. It is concluded, that the employment of TIF even in a very simplified form (extremely short-range) puts away a lot of problems characteristic to models limited by two-particle forces (collapse at iteratious in Hartry-Fock, simultaneous fitting of the binding energy of a nucleus and the binding energy of a nucleon, etc.) and makes it possible to obtain in a rather simple way such nuclear characteristics as nuclear binding energy, nuclear mean square root radii, nucleon density of a nucleus
Molecular dynamics and binary collisions modeling of the primary damage state of collision cascades
International Nuclear Information System (INIS)
Heinisch, H.L.; Singh, B.N.
1992-01-01
The objective of this work is to determine the spectral dependence of defect production and microstructure evolution for the development of fission-fusion correlations. Quantitative information on defect production in cascades in copper obtained from recent molecular dynamics (MD) simulations is compared to defect production information determined earlier with a model based on the binary collision approximation (BCA). The total numbers of residual defects, the fractions of them that are mobile, and the sizes of immobile clusters compare favorably, especially when the termination conditions of the two simulations are taken into account. A strategy is laid out for integrating the details of the cascade quenching phase determined by MD into a BCA-based model that is practical for simulating much higher energies and longer times than MD alone can achieve. The extraction of collisional phase information from MD simulations and the correspondence of MD and BCA versions of the collisional phase demonstrated at low energy
Molecular dynamics and binary collision modeling of the primary damage state of collision cascades
DEFF Research Database (Denmark)
Heinisch, H.L.; Singh, B.N.
1992-01-01
Quantitative information on defect production in cascades in copper obtained from recent molecular dynamics simulations is compared to defect production information determined earlier with a model based on the binary collision approximation (BCA). The total numbers of residual defects......, the fractions of them that are mobile, and the sizes of immobile clusters compare favorably, especially when the termination conditions of the two simulations are taken into account. A strategy is laid out for integrating the details of the cascade quenching phase determined by MD into a BCA-based model...... that is practical for simulating much higher energies and longer times than MD alone can achieve. The extraction of collisional phase information from MD simulations and the correspondence of MD and BCA versions of the collisional phase is demonstrated at low energy....
Sequence selection by dynamical symmetry breaking in an autocatalytic binary polymer model
DEFF Research Database (Denmark)
Fellermann, Harold; Tanaka, Shinpei; Rasmussen, Steen
2017-01-01
Template-directed replication of nucleic acids is at the essence of all living beings and a major milestone for any origin of life scenario. We present an idealized model of prebiotic sequence replication, where binary polymers act as templates for their autocatalytic replication, thereby serving...... as each others reactants and products in an intertwined molecular ecology. Our model demonstrates how autocatalysis alters the qualitative and quantitative system dynamics in counterintuitive ways. Most notably, numerical simulations reveal a very strong intrinsic selection mechanism that favors...... the appearance of a few population structures with highly ordered and repetitive sequence patterns when starting from a pool of monomers. We demonstrate both analytically and through simulation how this "selection of the dullest" is caused by continued symmetry breaking through random fluctuations...
Relativistic models of nuclear structure
International Nuclear Information System (INIS)
Gillet, V.; Kim, E.J.; Cauvin, M.; Kohmura, T.; Ohnaka, S.
1991-01-01
The introduction of the relativistic field formalism for the description of nuclear structure has improved our understanding of fundamental nuclear mechanisms such as saturation or many body forces. We discuss some of these progresses, both in the semi-classical mean field approximation and in a quantized meson field approach. (author)
Bi-dimensional null model analysis of presence-absence binary matrices.
Strona, Giovanni; Ulrich, Werner; Gotelli, Nicholas J
2018-01-01
Comparing the structure of presence/absence (i.e., binary) matrices with those of randomized counterparts is a common practice in ecology. However, differences in the randomization procedures (null models) can affect the results of the comparisons, leading matrix structural patterns to appear either "random" or not. Subjectivity in the choice of one particular null model over another makes it often advisable to compare the results obtained using several different approaches. Yet, available algorithms to randomize binary matrices differ substantially in respect to the constraints they impose on the discrepancy between observed and randomized row and column marginal totals, which complicates the interpretation of contrasting patterns. This calls for new strategies both to explore intermediate scenarios of restrictiveness in-between extreme constraint assumptions, and to properly synthesize the resulting information. Here we introduce a new modeling framework based on a flexible matrix randomization algorithm (named the "Tuning Peg" algorithm) that addresses both issues. The algorithm consists of a modified swap procedure in which the discrepancy between the row and column marginal totals of the target matrix and those of its randomized counterpart can be "tuned" in a continuous way by two parameters (controlling, respectively, row and column discrepancy). We show how combining the Tuning Peg with a wise random walk procedure makes it possible to explore the complete null space embraced by existing algorithms. This exploration allows researchers to visualize matrix structural patterns in an innovative bi-dimensional landscape of significance/effect size. We demonstrate the rational and potential of our approach with a set of simulated and real matrices, showing how the simultaneous investigation of a comprehensive and continuous portion of the null space can be extremely informative, and possibly key to resolving longstanding debates in the analysis of ecological
International Nuclear Information System (INIS)
Bayestehparvin, Bita; Nourozieh, Hossein; Kariznovi, Mohammad; Abedi, Jalal
2015-01-01
Highlights: • Phase behavior of the binary systems containing largely different components. • Equation of state modeling of binary polar and non-polar systems by utilizing different mixing rules. • Three different mixing rules (one-parameter, two-parameters and Wong–Sandler) coupled with Peng–Robinson equation of state. • Two-parameter mixing rule shows promoting results compared to one-parameter mixing rule. • Wong–Sandler mixing rule is unable to predict saturated liquid densities with sufficient accuracy. - Abstract: The present study mainly focuses on the phase behavior modeling of asymmetric binary mixtures. Capability of different mixing rules and volume shift in the prediction of solubility and saturated liquid density has been investigated. Different binary systems of (alkane + alkanol), (alkane + alkane), (carbon dioxide + alkanol), and (carbon dioxide + alkane) are considered. The composition and the density of saturated liquid phase at equilibrium condition are the properties of interest. Considering composition and saturated liquid density of different binary systems, three main objectives are investigated. First, three different mixing rules (one-parameter, two parameters and Wong–Sandler) coupled with Peng–Robinson equation of state were used to predict the equilibrium properties. The Wong–Sandler mixing rule was utilized with the non-random two-liquid (NRTL) model. Binary interaction coefficients and NRTL model parameters were optimized using the Levenberg–Marquardt algorithm. Second, to improve the density prediction, the volume translation technique was applied. Finally, Two different approaches were considered to tune the equation of state; regression of experimental equilibrium compositions and densities separately and spontaneously. The modeling results show that there is no superior mixing rule which can predict the equilibrium properties for different systems. Two-parameter and Wong–Sandler mixing rule show promoting
Multi-GPU hybrid programming accelerated three-dimensional phase-field model in binary alloy
Directory of Open Access Journals (Sweden)
Changsheng Zhu
2018-03-01
Full Text Available In the process of dendritic growth simulation, the computational efficiency and the problem scales have extremely important influence on simulation efficiency of three-dimensional phase-field model. Thus, seeking for high performance calculation method to improve the computational efficiency and to expand the problem scales has a great significance to the research of microstructure of the material. A high performance calculation method based on MPI+CUDA hybrid programming model is introduced. Multi-GPU is used to implement quantitative numerical simulations of three-dimensional phase-field model in binary alloy under the condition of multi-physical processes coupling. The acceleration effect of different GPU nodes on different calculation scales is explored. On the foundation of multi-GPU calculation model that has been introduced, two optimization schemes, Non-blocking communication optimization and overlap of MPI and GPU computing optimization, are proposed. The results of two optimization schemes and basic multi-GPU model are compared. The calculation results show that the use of multi-GPU calculation model can improve the computational efficiency of three-dimensional phase-field obviously, which is 13 times to single GPU, and the problem scales have been expanded to 8193. The feasibility of two optimization schemes is shown, and the overlap of MPI and GPU computing optimization has better performance, which is 1.7 times to basic multi-GPU model, when 21 GPUs are used.
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Liran Carmel
2010-01-01
Full Text Available Evolutionary binary characters are features of species or genes, indicating the absence (value zero or presence (value one of some property. Examples include eukaryotic gene architecture (the presence or absence of an intron in a particular locus, gene content, and morphological characters. In many studies, the acquisition of such binary characters is assumed to represent a rare evolutionary event, and consequently, their evolution is analyzed using various flavors of parsimony. However, when gain and loss of the character are not rare enough, a probabilistic analysis becomes essential. Here, we present a comprehensive probabilistic model to describe the evolution of binary characters on a bifurcating phylogenetic tree. A fast software tool, EREM, is provided, using maximum likelihood to estimate the parameters of the model and to reconstruct ancestral states (presence and absence in internal nodes and events (gain and loss events along branches.
Carmel, Liran; Wolf, Yuri I; Rogozin, Igor B; Koonin, Eugene V
2010-01-01
Evolutionary binary characters are features of species or genes, indicating the absence (value zero) or presence (value one) of some property. Examples include eukaryotic gene architecture (the presence or absence of an intron in a particular locus), gene content, and morphological characters. In many studies, the acquisition of such binary characters is assumed to represent a rare evolutionary event, and consequently, their evolution is analyzed using various flavors of parsimony. However, when gain and loss of the character are not rare enough, a probabilistic analysis becomes essential. Here, we present a comprehensive probabilistic model to describe the evolution of binary characters on a bifurcating phylogenetic tree. A fast software tool, EREM, is provided, using maximum likelihood to estimate the parameters of the model and to reconstruct ancestral states (presence and absence in internal nodes) and events (gain and loss events along branches).
Knee cartilage segmentation using active shape models and local binary patterns
González, Germán.; Escalante-Ramírez, Boris
2014-05-01
Segmentation of knee cartilage has been useful for opportune diagnosis and treatment of osteoarthritis (OA). This paper presents a semiautomatic segmentation technique based on Active Shape Models (ASM) combined with Local Binary Patterns (LBP) and its approaches to describe the surrounding texture of femoral cartilage. The proposed technique is tested on a 16-image database of different patients and it is validated through Leave- One-Out method. We compare different segmentation techniques: ASM-LBP, ASM-medianLBP, and ASM proposed by Cootes. The ASM-LBP approaches are tested with different ratios to decide which of them describes the cartilage texture better. The results show that ASM-medianLBP has better performance than ASM-LBP and ASM. Furthermore, we add a routine which improves the robustness versus two principal problems: oversegmentation and initialization.
Binary logistic regression modelling: Measuring the probability of relapse cases among drug addict
Ismail, Mohd Tahir; Alias, Siti Nor Shadila
2014-07-01
For many years Malaysia faced the drug addiction issues. The most serious case is relapse phenomenon among treated drug addict (drug addict who have under gone the rehabilitation programme at Narcotic Addiction Rehabilitation Centre, PUSPEN). Thus, the main objective of this study is to find the most significant factor that contributes to relapse to happen. The binary logistic regression analysis was employed to model the relationship between independent variables (predictors) and dependent variable. The dependent variable is the status of the drug addict either relapse, (Yes coded as 1) or not, (No coded as 0). Meanwhile the predictors involved are age, age at first taking drug, family history, education level, family crisis, community support and self motivation. The total of the sample is 200 which the data are provided by AADK (National Antidrug Agency). The finding of the study revealed that age and self motivation are statistically significant towards the relapse cases..
A Study of Precataclysmic Binaries Through Theoretic Modeling of Light Curves and Spectra
Mitrofanova, A. A.; Shimansky, V. V.; Borisov, N. V.
2017-06-01
The article presents results of three pre-cataclysmic binaries (PN G068.1+11.0, TW Crv and RE J2013+4002) investigation. Spectroscopic and photometric observations were obtained on BTA and Zeiss-1000 of SAO RAS and on RTT-150. We used the modeling of light curves and spectra to determine the fundamental parameters for all three systems. The PN G068.1+11.0 parameters were obtained with the use of the evolutionary tracks for the nuclei of planetary nebulae of different masses. According to the results of the study, it was found that the secondary components of PN G068.1+11.0 and TW Crv have luminosity excess, but secondary component of RE J2013+4002 doesn't have one.
Smith, J. E., Jr.
1983-01-01
Succinonitrile-water and diethylene glycol-ethyl salicylate are two transparent systems which have been studied as monotectic binary metallic alloy solidification models. Being transparent, these systems allow for the direct observations of phase transformations and solidification reactions. The objective was to develop a screening technique to find systems of interest and then experimentally measure those systems. The succinonitrile-water system was used to check the procedures. To simulate the phase diagram of the system, two computer programs which determine solid-liquid and liquid-liquid equilibria were obtained. These programs use the UNIFAC method to determine activity coefficients and together with several other programs were used to predict the phase diagram. An experimental apparatus was developed and the succinonitrile-water phase diagram measured. The diagram was compared to both the simulation and literature data. Substantial differences were found in the comparisons which serve to demonstrate the need for this procedure.
Kamaruddin, Ainur Amira; Ali, Zalila; Noor, Norlida Mohd.; Baharum, Adam; Ahmad, Wan Muhamad Amir W.
2014-07-01
Logistic regression analysis examines the influence of various factors on a dichotomous outcome by estimating the probability of the event's occurrence. Logistic regression, also called a logit model, is a statistical procedure used to model dichotomous outcomes. In the logit model the log odds of the dichotomous outcome is modeled as a linear combination of the predictor variables. The log odds ratio in logistic regression provides a description of the probabilistic relationship of the variables and the outcome. In conducting logistic regression, selection procedures are used in selecting important predictor variables, diagnostics are used to check that assumptions are valid which include independence of errors, linearity in the logit for continuous variables, absence of multicollinearity, and lack of strongly influential outliers and a test statistic is calculated to determine the aptness of the model. This study used the binary logistic regression model to investigate overweight and obesity among rural secondary school students on the basis of their demographics profile, medical history, diet and lifestyle. The results indicate that overweight and obesity of students are influenced by obesity in family and the interaction between a student's ethnicity and routine meals intake. The odds of a student being overweight and obese are higher for a student having a family history of obesity and for a non-Malay student who frequently takes routine meals as compared to a Malay student.
Risk of Recurrence in Operated Parasagittal Meningiomas: A Logistic Binary Regression Model.
Escribano Mesa, José Alberto; Alonso Morillejo, Enrique; Parrón Carreño, Tesifón; Huete Allut, Antonio; Narro Donate, José María; Méndez Román, Paddy; Contreras Jiménez, Ascensión; Pedrero García, Francisco; Masegosa González, José
2018-02-01
Parasagittal meningiomas arise from the arachnoid cells of the angle formed between the superior sagittal sinus (SSS) and the brain convexity. In this retrospective study, we focused on factors that predict early recurrence and recurrence times. We reviewed 125 patients with parasagittal meningiomas operated from 1985 to 2014. We studied the following variables: age, sex, location, laterality, histology, surgeons, invasion of the SSS, Simpson removal grade, follow-up time, angiography, embolization, radiotherapy, recurrence and recurrence time, reoperation, neurologic deficit, degree of dependency, and patient status at the end of follow-up. Patients ranged in age from 26 to 81 years (mean 57.86 years; median 60 years). There were 44 men (35.2%) and 81 women (64.8%). There were 57 patients with neurologic deficits (45.2%). The most common presenting symptom was motor deficit. World Health Organization grade I tumors were identified in 104 patients (84.6%), and the majority were the meningothelial type. Recurrence was detected in 34 cases. Time of recurrence was 9 to 336 months (mean: 84.4 months; median: 79.5 months). Male sex was identified as an independent risk for recurrence with relative risk 2.7 (95% confidence interval 1.21-6.15), P = 0.014. Kaplan-Meier curves for recurrence had statistically significant differences depending on sex, age, histologic type, and World Health Organization histologic grade. A binary logistic regression was made with the Hosmer-Lemeshow test with P > 0.05; sex, tumor size, and histologic type were used in this model. Male sex is an independent risk factor for recurrence that, associated with other factors such tumor size and histologic type, explains 74.5% of all cases in a binary regression model. Copyright © 2017 Elsevier Inc. All rights reserved.
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BOJAN D. DJORDJEVIC
2007-12-01
Full Text Available Although many cubic equations of state coupled with van der Waals-one fluid mixing rules including temperature dependent interaction parameters are sufficient for representing phase equilibria and excess properties (excess molar enthalpy HE, excess molar volume VE, etc., difficulties appear in the correlation and prediction of thermodynamic properties of complex mixtures at various temperature and pressure ranges. Great progress has been made by a new approach based on CEOS/GE models. This paper reviews the last six-year of progress achieved in modelling of the volumetric properties for complex binary and ternary systems of non-electrolytes by the CEOS and CEOS/GE approaches. In addition, the vdW1 and TCBT models were used to estimate the excess molar volume VE of ternary systems methanol + chloroform + benzene and 1-propanol + chloroform + benzene, as well as the corresponding binaries methanol + chloroform, chloroform + benzene, 1-propanol + chloroform and 1-propanol + benzene at 288.15–313.15 K and atmospheric pressure. Also, prediction of VE for both ternaries by empirical models (Radojković, Kohler, Jackob–Fitzner, Colinet, Tsao–Smith, Toop, Scatchard, Rastogi was performed.
The nuclear reaction model code MEDICUS
International Nuclear Information System (INIS)
Ibishia, A.I.
2008-01-01
The new computer code MEDICUS has been used to calculate cross sections of nuclear reactions. The code, implemented in MATLAB 6.5, Mathematica 5, and Fortran 95 programming languages, can be run in graphical and command line mode. Graphical User Interface (GUI) has been built that allows the user to perform calculations and to plot results just by mouse clicking. The MS Windows XP and Red Hat Linux platforms are supported. MEDICUS is a modern nuclear reaction code that can compute charged particle-, photon-, and neutron-induced reactions in the energy range from thresholds to about 200 MeV. The calculation of the cross sections of nuclear reactions are done in the framework of the Exact Many-Body Nuclear Cluster Model (EMBNCM), Direct Nuclear Reactions, Pre-equilibrium Reactions, Optical Model, DWBA, and Exciton Model with Cluster Emission. The code can be used also for the calculation of nuclear cluster structure of nuclei. We have calculated nuclear cluster models for some nuclei such as 177 Lu, 90 Y, and 27 Al. It has been found that nucleus 27 Al can be represented through the two different nuclear cluster models: 25 Mg + d and 24 Na + 3 He. Cross sections in function of energy for the reaction 27 Al( 3 He,x) 22 Na, established as a production method of 22 Na, are calculated by the code MEDICUS. Theoretical calculations of cross sections are in good agreement with experimental results. Reaction mechanisms are taken into account. (author)
Evaluation of Thermodynamic Models for Predicting Phase Equilibria of CO2 + Impurity Binary Mixture
Shin, Byeong Soo; Rho, Won Gu; You, Seong-Sik; Kang, Jeong Won; Lee, Chul Soo
2018-03-01
For the design and operation of CO2 capture and storage (CCS) processes, equation of state (EoS) models are used for phase equilibrium calculations. Reliability of an EoS model plays a crucial role, and many variations of EoS models have been reported and continue to be published. The prediction of phase equilibria for CO2 mixtures containing SO2, N2, NO, H2, O2, CH4, H2S, Ar, and H2O is important for CO2 transportation because the captured gas normally contains small amounts of impurities even though it is purified in advance. For the design of pipelines in deep sea or arctic conditions, flow assurance and safety are considered priority issues, and highly reliable calculations are required. In this work, predictive Soave-Redlich-Kwong, cubic plus association, Groupe Européen de Recherches Gazières (GERG-2008), perturbed-chain statistical associating fluid theory, and non-random lattice fluids hydrogen bond EoS models were compared regarding performance in calculating phase equilibria of CO2-impurity binary mixtures and with the collected literature data. No single EoS could cover the entire range of systems considered in this study. Weaknesses and strong points of each EoS model were analyzed, and recommendations are given as guidelines for safe design and operation of CCS processes.
Cook, James P; Mahajan, Anubha; Morris, Andrew P
2017-02-01
Linear mixed models are increasingly used for the analysis of genome-wide association studies (GWAS) of binary phenotypes because they can efficiently and robustly account for population stratification and relatedness through inclusion of random effects for a genetic relationship matrix. However, the utility of linear (mixed) models in the context of meta-analysis of GWAS of binary phenotypes has not been previously explored. In this investigation, we present simulations to compare the performance of linear and logistic regression models under alternative weighting schemes in a fixed-effects meta-analysis framework, considering designs that incorporate variable case-control imbalance, confounding factors and population stratification. Our results demonstrate that linear models can be used for meta-analysis of GWAS of binary phenotypes, without loss of power, even in the presence of extreme case-control imbalance, provided that one of the following schemes is used: (i) effective sample size weighting of Z-scores or (ii) inverse-variance weighting of allelic effect sizes after conversion onto the log-odds scale. Our conclusions thus provide essential recommendations for the development of robust protocols for meta-analysis of binary phenotypes with linear models.
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Claudia Pedroza
2016-08-01
Full Text Available Abstract Background Reporting of absolute risk difference (RD is recommended for clinical and epidemiological prospective studies. In analyses of multicenter studies, adjustment for center is necessary when randomization is stratified by center or when there is large variation in patients outcomes across centers. While regression methods are used to estimate RD adjusted for baseline predictors and clustering, no formal evaluation of their performance has been previously conducted. Methods We performed a simulation study to evaluate 6 regression methods fitted under a generalized estimating equation framework: binomial identity, Poisson identity, Normal identity, log binomial, log Poisson, and logistic regression model. We compared the model estimates to unadjusted estimates. We varied the true response function (identity or log, number of subjects per center, true risk difference, control outcome rate, effect of baseline predictor, and intracenter correlation. We compared the models in terms of convergence, absolute bias and coverage of 95 % confidence intervals for RD. Results The 6 models performed very similar to each other for the majority of scenarios. However, the log binomial model did not converge for a large portion of the scenarios including a baseline predictor. In scenarios with outcome rate close to the parameter boundary, the binomial and Poisson identity models had the best performance, but differences from other models were negligible. The unadjusted method introduced little bias to the RD estimates, but its coverage was larger than the nominal value in some scenarios with an identity response. Under the log response, coverage from the unadjusted method was well below the nominal value (<80 % for some scenarios. Conclusions We recommend the use of a binomial or Poisson GEE model with identity link to estimate RD for correlated binary outcome data. If these models fail to run, then either a logistic regression, log Poisson
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Zbisław Tabor
2011-05-01
Full Text Available In the study an algorithm based on a lattice gas model is proposed as a tool for enhancing quality of lowresolution images of binary structures. Analyzed low-resolution gray-level images are replaced with binary images, in which pixel size is decreased. The intensity in the pixels of these new images is determined by corresponding gray-level intensities in the original low-resolution images. Then the white phase pixels in the binary images are assumed to be particles interacting with one another, interacting with properly defined external field and allowed to diffuse. The evolution is driven towards a state with maximal energy by Metropolis algorithm. This state is used to estimate the imaged object. The performance of the proposed algorithm and local and global thresholding methods are compared.
Numerical modeling of two-phase binary fluid mixing using mixed finite elements
Sun, Shuyu
2012-07-27
Diffusion coefficients of dense gases in liquids can be measured by considering two-phase binary nonequilibrium fluid mixing in a closed cell with a fixed volume. This process is based on convection and diffusion in each phase. Numerical simulation of the mixing often requires accurate algorithms. In this paper, we design two efficient numerical methods for simulating the mixing of two-phase binary fluids in one-dimensional, highly permeable media. Mathematical model for isothermal compositional two-phase flow in porous media is established based on Darcy\\'s law, material balance, local thermodynamic equilibrium for the phases, and diffusion across the phases. The time-lag and operator-splitting techniques are used to decompose each convection-diffusion equation into two steps: diffusion step and convection step. The Mixed finite element (MFE) method is used for diffusion equation because it can achieve a high-order and stable approximation of both the scalar variable and the diffusive fluxes across grid-cell interfaces. We employ the characteristic finite element method with moving mesh to track the liquid-gas interface. Based on the above schemes, we propose two methods: single-domain and two-domain methods. The main difference between two methods is that the two-domain method utilizes the assumption of sharp interface between two fluid phases, while the single-domain method allows fractional saturation level. Two-domain method treats the gas domain and the liquid domain separately. Because liquid-gas interface moves with time, the two-domain method needs work with a moving mesh. On the other hand, the single-domain method allows the use of a fixed mesh. We derive the formulas to compute the diffusive flux for MFE in both methods. The single-domain method is extended to multiple dimensions. Numerical results indicate that both methods can accurately describe the evolution of the pressure and liquid level. © 2012 Springer Science+Business Media B.V.
Honda, Hidehito; Matsuka, Toshihiko; Ueda, Kazuhiro
2017-01-01
Some researchers on binary choice inference have argued that people make inferences based on simple heuristics, such as recognition, fluency, or familiarity. Others have argued that people make inferences based on available knowledge. To examine the boundary between heuristic and knowledge usage, we examine binary choice inference processes in…
Model many-body Stoner Hamiltonian for binary FeCr alloys
Nguyen-Manh, D.; Dudarev, S. L.
2009-09-01
We derive a model tight-binding many-body d -electron Stoner Hamiltonian for FeCr binary alloys and investigate the sensitivity of its mean-field solutions to the choice of hopping integrals and the Stoner exchange parameters. By applying the local charge-neutrality condition within a self-consistent treatment we show that the negative enthalpy-of-mixing anomaly characterizing the alloy in the low chromium concentration limit is due entirely to the presence of the on-site exchange Stoner terms and that the occurrence of this anomaly is not specifically related to the choice of hopping integrals describing conventional chemical bonding between atoms in the alloy. The Bain transformation pathway computed, using the proposed model Hamiltonian, for the Fe15Cr alloy configuration is in excellent agreement with ab initio total-energy calculations. Our investigation also shows how the parameters of a tight-binding many-body model Hamiltonian for a magnetic alloy can be derived from the comparison of its mean-field solutions with other, more accurate, mean-field approximations (e.g., density-functional calculations), hence stimulating the development of large-scale computational algorithms for modeling radiation damage effects in magnetic alloys and steels.
A magnetic model for low/hard state of black hole binaries
Ye, Yong-Chun; Wang, Ding-Xiong; Huang, Chang-Yin; Cao, Xiao-Feng
2016-03-01
A magnetic model for the low/hard state (LHS) of two black hole X-ray binaries (BHXBs), H1743-322 and GX 339-4, is proposed based on transport of the magnetic field from a companion into an accretion disk around a black hole (BH). This model consists of a truncated thin disk with an inner advection-dominated accretion flow (ADAF). The spectral profiles of the sources are fitted in agreement with the data observed at four different dates corresponding to the rising phase of the LHS. In addition, the association of the LHS with a quasi-steady jet is modeled based on transport of magnetic field, where the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes are invoked to drive the jets from BH and inner ADAF. It turns out that the steep radio/X-ray correlations observed in H1743-322 and GX 339-4 can be interpreted based on our model.
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Henrique Silva Furtado
2009-09-01
Full Text Available Numerical simulation of solute trapping during solidification, using two phase-field model for dilute binary alloys developed by Kim et al. [Phys. Rev. E, 60, 7186 (1999] and Ramirez et al. [Phys. Rev. E, 69, 05167 (2004] is presented here. The simulations on dilute Cu-Ni alloy are in good agreement with one dimensional analytic solution of sharp interface model. Simulation conducted under small solidification velocity using solid-liquid interface thickness (2λ of 8 nanometers reproduced the solute (Cu equilibrium partition coefficient. The spurious numerical solute trapping in solid phase, due to the interface thickness was negligible. A parameter used in analytical solute trapping model was determined by isothermal phase-field simulation of Ni-Cu alloy. Its application to Si-As and Si-Bi alloys reproduced results that agree reasonably well with experimental data. A comparison between the three models of solute trapping (Aziz, Sobolev and Galenko [Phys. Rev. E, 76, 031606 (2007] was performed. It resulted in large differences in predicting the solidification velocity for partition-less solidification, indicating the necessity for new and more acute experimental data.
International Nuclear Information System (INIS)
Olson, Gordon L.
2016-01-01
One-dimensional models for the transport of radiation through binary stochastic media do not work in multi-dimensions. Authors have attempted to modify or extend the 1D models to work in multidimensions without success. Analytic one-dimensional models are successful in 1D only when assuming greatly simplified physics. State of the art theories for stochastic media radiation transport do not address multi-dimensions and temperature-dependent physics coefficients. Here, the concept of effective opacities and effective heat capacities is found to well represent the ensemble averaged transport solutions in cases with gray or multigroup temperature-dependent opacities and constant or temperature-dependent heat capacities. In every case analyzed here, effective physics coefficients fit the transport solutions over a useful range of parameter space. The transport equation is solved with the spherical harmonics method with angle orders of n=1 and 5. Although the details depend on what order of solution is used, the general results are similar, independent of angular order. - Highlights: • Gray and multigroup radiation transport is done through 2D stochastic media. • Approximate models for the mean radiation field are found for all test problems. • Effective opacities are adjusted to fit the means of stochastic media transport. • Test problems include temperature dependent opacities and heat capacities • Transport solutions are done with angle orders n=1 and 5.
International Nuclear Information System (INIS)
Li, Tao; Deng, Renlun; Wu, Gang; Gu, Pengfei; Hu, Yonghong; Yang, Wenge; Yu, Yemin; Zhang, Yuhao; Yang, Chen
2017-01-01
Highlights: • The solubility increased with increasing temperature. • Data were fitted using the modified Apelblat equation and other models in pure solvents. • Data were fitted using the modified Apelblat equation and other models in binary solvent mixture. - Abstract: Data on corresponding solid–liquid equilibrium of 6-benzyladenine in different solvents are essential for a preliminary study of industrial applications. In this paper, the solid–liquid equilibrium of 6-benzyladenine in methanol, ethanol, 1-butanol, acetone, acetonitrile, ethyl acetate, dimethyl formamide and tetrahydrofuran pure solvents and (dimethyl formamide + actone) mixture solvents was explored within the temperature range from (278.15 to 333.15) K under 0.1 MPa. For the temperature range investigated, the solubility of 6-benzyladenine in the solvents increased with increasing temperature. The solubility of 6-benzyladenine in dimethyl formamide is superior to other selected pure solvents. The modified Apelblat model, the Buchowski-Ksiazaczak λh model, and the ideal model were adopted to describe and predict the change tendency of solubility. Computational results showed that the modified Apelblat model has more advantages than the other two models. The solubility results were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich-Kister (CNIBS/R-K) model, Jouyban-Acree model and Ma model in (dimethyl formamide + acetone) binary solvent mixture. Computational results showed that the modified Apelblat model is superior to the other equations.
DEFF Research Database (Denmark)
Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht
2011-01-01
In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid–liqu...
Chan, Jennifer S K
2016-05-01
Dropouts are common in longitudinal study. If the dropout probability depends on the missing observations at or after dropout, this type of dropout is called informative (or nonignorable) dropout (ID). Failure to accommodate such dropout mechanism into the model will bias the parameter estimates. We propose a conditional autoregressive model for longitudinal binary data with an ID model such that the probabilities of positive outcomes as well as the drop-out indicator in each occasion are logit linear in some covariates and outcomes. This model adopting a marginal model for outcomes and a conditional model for dropouts is called a selection model. To allow for the heterogeneity and clustering effects, the outcome model is extended to incorporate mixture and random effects. Lastly, the model is further extended to a novel model that models the outcome and dropout jointly such that their dependency is formulated through an odds ratio function. Parameters are estimated by a Bayesian approach implemented using the user-friendly Bayesian software WinBUGS. A methadone clinic dataset is analyzed to illustrate the proposed models. Result shows that the treatment time effect is still significant but weaker after allowing for an ID process in the data. Finally the effect of drop-out on parameter estimates is evaluated through simulation studies. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Model of cooling nuclear fuel rod in the nuclear reactor
International Nuclear Information System (INIS)
Lavicka, David; Polansky, Jiri
2010-01-01
The following topics are described: Some basic requirements for nuclear fuel rods; The VVER 1000 fuel rod; Classification of the two-phase flow in the vertical tube; Type of heat transfer crisis in the vertical tube; Experimental apparatus; Model of the nuclear fuel rod and spacers; Potential of the experimental apparatus (velocity profile measurement via PIV; thermal flow field measurement by the PLIF method; cooling graph in dependence on the fuel rod temperature; comparison of the hydrodynamic properties with respect to the design features of the spacers). (P.A.)
Soot modeling of counterflow diffusion flames of ethylene-based binary mixture fuels
Wang, Yu
2015-03-01
A soot model was developed based on the recently proposed PAH growth mechanism for C1-C4 gaseous fuels (KAUST PAH Mechanism 2, KM2) that included molecular growth up to coronene (A7) to simulate soot formation in counterflow diffusion flames of ethylene and its binary mixtures with methane, ethane and propane based on the method of moments. The soot model has 36 soot nucleation reactions from 8 PAH molecules including pyrene and larger PAHs. Soot surface growth reactions were based on a modified hydrogen-abstraction-acetylene-addition (HACA) mechanism in which CH3, C3H3 and C2H radicals were included in the hydrogen abstraction reactions in addition to H atoms. PAH condensation on soot particles was also considered. The experimentally measured profiles of soot volume fraction, number density, and particle size were well captured by the model for the baseline case of ethylene along with the cases involving mixtures of fuels. The simulation results, which were in qualitative agreement with the experimental data in the effects of binary fuel mixing on the sooting structures of the measured flames, showed in particular that 5% addition of propane (ethane) led to an increase in the soot volume fraction of the ethylene flame by 32% (6%), despite the fact that propane and ethane are less sooting fuels than is ethylene, which is in reasonable agreement with experiments of 37% (14%). The model revealed that with 5% addition of methane, there was an increase of 6% in the soot volume fraction. The average soot particle sizes were only minimally influenced while the soot number densities were increased by the fuel mixing. Further analysis of the numerical data indicated that the chemical cross-linking effect between ethylene and the dopant fuels resulted in an increase in PAH formation, which led to higher soot nucleation rates and therefore higher soot number densities. On the other hand, the rates of soot surface growth per unit surface area through the HACA mechanism were
Safety Cultural Competency Modeling in Nuclear Organizations
Energy Technology Data Exchange (ETDEWEB)
Kim, Sa Kil; Oh, Yeon Ju; Luo, Meiling; Lee, Yong Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2014-05-15
The nuclear safety cultural competency model should be supplemented through a bottom-up approach such as behavioral event interview. The developed model, however, is meaningful for determining what should be dealt for enhancing safety cultural competency of nuclear organizations. The more details of the developing process, results, and applications will be introduced later. Organizational culture include safety culture in terms of its organizational characteristics.
Nuclear fuel: modelling the advanced plutonium assembly
International Nuclear Information System (INIS)
Kaoua, Th.; Lenain, R.
2004-01-01
The benefits of modeling in the nuclear sector are illustrated by the example of the design study for a new plutonium fuel assembly, APA, capable of ensuring maximum consumption of this fuel in pressurized-water reactors. Beyond the physical design of the assembly and its integration into the reactor, this serves for the working out of a complete materials flow and assists in modeling production from the entire inventory of nuclear power stations. (authors)
Nuclear fuel: modelling the advanced plutonium assembly
International Nuclear Information System (INIS)
N'kaoua, Th.; Lenain, R.
2002-01-01
The benefits of modeling in the nuclear sector are illustrated by the example of the design study for a new plutonium fuel assembly, APA, capable of ensuring maximum consumption of this fuel in pressurized-water reactors. Beyond the physical design of the assembly and its integration into the reactor, this serves for the working out of a complete materials flow and assists in modeling production from the entire inventory of nuclear power stations. (authors)
The new business model for nuclear
International Nuclear Information System (INIS)
Galange, D.
2006-01-01
New nuclear development will require new business models that ensure maximum risk mitigation for the plant owner and rate payers. To deliver this model, AECL has joined with leading members of the nuclear industry to form Team CANDU. This presentation will introduce contracting structures that have been used by Team CANDU members to reduce plant delivery risk in an ongoing record of successful project completions over the last decade. (author)
Nuclear clustering - a cluster core model study
International Nuclear Information System (INIS)
Paul Selvi, G.; Nandhini, N.; Balasubramaniam, M.
2015-01-01
Nuclear clustering, similar to other clustering phenomenon in nature is a much warranted study, since it would help us in understanding the nature of binding of the nucleons inside the nucleus, closed shell behaviour when the system is highly deformed, dynamics and structure at extremes. Several models account for the clustering phenomenon of nuclei. We present in this work, a cluster core model study of nuclear clustering in light mass nuclei
Features of non-congruent phase transition in modified Coulomb model of the binary ionic mixture
International Nuclear Information System (INIS)
Stroev, N E; Iosilevskiy, I L
2016-01-01
Non-congruent gas-liquid phase transition (NCPT) have been studied previously in modified Coulomb model of a binary ionic mixture C(+6) + O(+8) on a uniformly compressible ideal electronic background /BIM(∼)/. The features of NCPT in improved version of the BIM(∼) model for the same mixture on background of non-ideal electronic Fermi-gas and comparison it with the previous calculations are the subject of present study. Analytical fits for Coulomb corrections to equation of state of electronic and ionic subsystems were used in present calculations within the Gibbs-Guggenheim conditions of non-congruent phase equilibrium. Parameters of critical point-line were calculated on the entire range of proportions of mixed ions 0 < X < 1. Strong “distillation” effect was found for NCPT in the present BIM(∼) model. Just similar distillation was obtained in the variant of NCPT in dense nuslear matter. The absence of azeotropic compositions was revealed in studied variants of BIM(∼) in contrast to an explicit existence of the azeotropic compositions for the NCPT in chemically reacting plasmas and in astrophysical applications. (paper)
Features of non-congruent phase transition in modified Coulomb model of the binary ionic mixture
Stroev, N. E.; Iosilevskiy, I. L.
2016-11-01
Non-congruent gas-liquid phase transition (NCPT) have been studied previously in modified Coulomb model of a binary ionic mixture C(+6) + O(+8) on a uniformly compressible ideal electronic background /BIM(∼)/. The features of NCPT in improved version of the BIM(∼) model for the same mixture on background of non-ideal electronic Fermi-gas and comparison it with the previous calculations are the subject of present study. Analytical fits for Coulomb corrections to equation of state of electronic and ionic subsystems were used in present calculations within the Gibbs-Guggenheim conditions of non-congruent phase equilibrium. Parameters of critical point-line were calculated on the entire range of proportions of mixed ions 0 distillation” effect was found for NCPT in the present BIM(∼) model. Just similar distillation was obtained in the variant of NCPT in dense nuslear matter. The absence of azeotropic compositions was revealed in studied variants of BIM(∼) in contrast to an explicit existence of the azeotropic compositions for the NCPT in chemically reacting plasmas and in astrophysical applications.
Calculating the Probability of Returning a Loan with Binary Probability Models
Directory of Open Access Journals (Sweden)
Julian Vasilev
2014-12-01
Full Text Available The purpose of this article is to give a new approach in calculating the probability of returning a loan. A lot of factors affect the value of the probability. In this article by using statistical and econometric models some influencing factors are proved. The main approach is concerned with applying probit and logit models in loan management institutions. A new aspect of the credit risk analysis is given. Calculating the probability of returning a loan is a difficult task. We assume that specific data fields concerning the contract (month of signing, year of signing, given sum and data fields concerning the borrower of the loan (month of birth, year of birth (age, gender, region, where he/she lives may be independent variables in a binary logistics model with a dependent variable “the probability of returning a loan”. It is proved that the month of signing a contract, the year of signing a contract, the gender and the age of the loan owner do not affect the probability of returning a loan. It is proved that the probability of returning a loan depends on the sum of contract, the remoteness of the loan owner and the month of birth. The probability of returning a loan increases with the increase of the given sum, decreases with the proximity of the customer, increases for people born in the beginning of the year and decreases for people born at the end of the year.
Dynamic modelling of nuclear steam generators
International Nuclear Information System (INIS)
Kerlin, T.W.; Katz, E.M.; Freels, J.; Thakkar, J.
1980-01-01
Moving boundary, nodal models with dynamic energy balances, dynamic mass balances, quasi-static momentum balances, and an equivalent single channel approach have been developed for steam generators used in nuclear power plants. The model for the U-tube recirculation type steam generator is described and comparisons are made of responses from models of different complexity; non-linear versus linear, high-order versus low order, detailed modeling of the control system versus a simple control assumption. The results of dynamic tests on nuclear power systems show that when this steam generator model is included in a system simulation there is good agreement with actual plant performance. (author)
Modeling news dissemination on nuclear issues
Energy Technology Data Exchange (ETDEWEB)
Reis Junior, Jose S.B.; Barroso, Antonio C.O.; Menezes, Mario O., E-mail: jsbrj@ime.usp.b, E-mail: barroso@ipen.b, E-mail: mario@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2011-07-01
Using a modified epidemiological model, the dissemination of news by media agents after the occurrence of large scale disasters was studied. A modified compartmented model was developed in a previous paper presented at INAC 2007. There it used to study to the Chernobyl's nuclear accident (1986) and the Concorde airplane crash (2000). Now the model has been applied to a larger and more diverse group of events - nuclear, non-nuclear and naturally caused disasters. To be comprehensive, old and recent events from various regions of the world were selected. A more robust news repository was used, and improved search techniques were developed to ensure that the scripts would not count false positive news. The same model was used but with improved non-linear embedded simulation optimization algorithms to generate the parameters of interest for our model. Individual parameters and some specific combination of them allow some interesting perceptions on how the nature of the accident / disaster gives rise to different profiles of growth and decay of the news. In our studies events involving nuclear causes generate news repercussion with more explosive / robust surge profiles and longer decaying tails than those of other natures. As a consequence of these differences, public opinion and policy makers are also much more sensitive to some issues than to others. The model, through its epidemiological parameters, shows in quantitative manner how 'nervous' the media content generators are with respect to nuclear installations and how resilient this negative feelings about nuclear is. (author)
Modeling news dissemination on nuclear issues
International Nuclear Information System (INIS)
Reis Junior, Jose S.B.; Barroso, Antonio C.O.; Menezes, Mario O.
2011-01-01
Using a modified epidemiological model, the dissemination of news by media agents after the occurrence of large scale disasters was studied. A modified compartmented model was developed in a previous paper presented at INAC 2007. There it used to study to the Chernobyl's nuclear accident (1986) and the Concorde airplane crash (2000). Now the model has been applied to a larger and more diverse group of events - nuclear, non-nuclear and naturally caused disasters. To be comprehensive, old and recent events from various regions of the world were selected. A more robust news repository was used, and improved search techniques were developed to ensure that the scripts would not count false positive news. The same model was used but with improved non-linear embedded simulation optimization algorithms to generate the parameters of interest for our model. Individual parameters and some specific combination of them allow some interesting perceptions on how the nature of the accident / disaster gives rise to different profiles of growth and decay of the news. In our studies events involving nuclear causes generate news repercussion with more explosive / robust surge profiles and longer decaying tails than those of other natures. As a consequence of these differences, public opinion and policy makers are also much more sensitive to some issues than to others. The model, through its epidemiological parameters, shows in quantitative manner how 'nervous' the media content generators are with respect to nuclear installations and how resilient this negative feelings about nuclear is. (author)
Energy Technology Data Exchange (ETDEWEB)
Pötzschner, B.; Mohamed, F.; Lichtinger, A.; Bock, D.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2015-10-21
We study a dynamically asymmetric binary glass former with the low-T{sub g} component m-tri-cresyl phosphate (m-TCP: T{sub g} = 206 K) and a spirobichroman derivative as a non-polymeric high-T{sub g} component (T{sub g} = 382 K) by means of {sup 1}H nuclear magnetic resonance (NMR), {sup 31}P NMR, and dielectric spectroscopy which allow component-selectively probing the dynamics. The entire concentration range is covered, and two main relaxation processes with two T{sub g} are identified, T{sub g1} and T{sub g2}. The slower one is attributed to the high-T{sub g} component (α{sub 1}-process), and the faster one is related to the m-TCP molecules (α{sub 2}-process). Yet, there are indications that a small fraction of m-TCP is associated also with the α{sub 1}-process. While the α{sub 1}-relaxation only weakly broadens upon adding m-TCP, the α{sub 2}-relaxation becomes extremely stretched leading to quasi-logarithmic correlation functions at low m-TCP concentrations—as probed by {sup 31}P NMR stimulated echo experiments. Frequency-temperature superposition does not apply for the α{sub 2}-process and it reflects an isotropic, liquid-like motion which is observed even below T{sub g1}, i.e., in the matrix of the arrested high-T{sub g} molecules. As proven by 2D {sup 31}P NMR, the corresponding dynamic heterogeneities are of transient nature, i.e., exchange occurs within the distribution G(lnτ{sub α2}). At T{sub g1} a crossover is found for the temperature dependence of (mean) τ{sub α2}(T) from non-Arrhenius above to Arrhenius below T{sub g1} which is attributed to intrinsic confinement effects. This “fragile-to-strong” transition also leads to a re-decrease of T{sub g2}(c{sub m−TCP}) at low concentration c{sub m−TCP}, i.e., a maximum is observed in T{sub g2}(c{sub m−TCP}) while T{sub g1}(c{sub m−TCP}) displays the well-known plasticizer effect. Although only non-polymeric components are involved, we re-discover essentially all features previously
World Integrated Nuclear Evaluation System: Model documentation
International Nuclear Information System (INIS)
1991-12-01
The World Integrated Nuclear Evaluation System (WINES) is an aggregate demand-based partial equilibrium model used by the Energy Information Administration (EIA) to project long-term domestic and international nuclear energy requirements. WINES follows a top-down approach in which economic growth rates, delivered energy demand growth rates, and electricity demand are projected successively to ultimately forecast total nuclear generation and nuclear capacity. WINES could be potentially used to produce forecasts for any country or region in the world. Presently, WINES is being used to generate long-term forecasts for the United States, and for all countries with commercial nuclear programs in the world, excluding countries located in centrally planned economic areas. Projections for the United States are developed for the period from 2010 through 2030, and for other countries for the period starting in 2000 or 2005 (depending on the country) through 2010. EIA uses a pipeline approach to project nuclear capacity for the period between 1990 and the starting year for which the WINES model is used. This approach involves a detailed accounting of existing nuclear generating units and units under construction, their capacities, their actual or estimated time of completion, and the estimated date of retirements. Further detail on this approach can be found in Appendix B of Commercial Nuclear Power 1991: Prospects for the United States and the World
A Application of WD Model to EB Type Contact Binary System
Directory of Open Access Journals (Sweden)
Su-Yeon Oh
2000-12-01
Full Text Available The EB type contact binaries show large temperature difference ( T 1,000K between two components. Thus we have modified the mode 3 of the WD program to adjust albedos, limb darkening coefficients and gravity darkening exponents for both components of such binaries, while the values for those parameters should be same for both components in the original WD program. Both of the modified and the original versions have been applied to the EB type contact binaries such as DO Cas, GO Cyg, and FS Lup. The computed light curves with modified version fit better to the observations.
International Nuclear Model. Volume 3. Program description
International Nuclear Information System (INIS)
Andress, D.
1985-01-01
This is Volume 3 of three volumes of documentation of the International Nuclear Model (INM). This volume presents the Program Description of the International Nuclear Model, which was developed for the Nuclear and Alternate Fuels Division (NAFD), Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA), US Department of Energy (DOE). The International Nuclear Model (INM) is a comprehensive model of the commercial nuclear power industry. It simulates economic decisions for reactor deployment and fuel management decision based on an input set of technical economic and scenario parameters. The technical parameters include reactor operating characteristics, fuel cycle timing and mass loss factors, and enrichment tails assays. Economic parameters include fuel cycle costs, financial data, and tax alternatives. INM has a broad range of scenario options covering, for example, process constraints, interregional activities, reprocessing, and fuel management selection. INM reports reactor deployment schedules, electricity generation, and fuel cycle requirements and costs. It also has specialized reports for extended burnup and permanent disposal. Companion volumes to Volume 3 are: Volume 1 - Model Overview, and Volume 2 - Data Base Relationships
Global nuclear material flow/control model
International Nuclear Information System (INIS)
Dreicer, J.S.; Rutherford, D.S.; Fasel, P.K.; Riese, J.M.
1997-01-01
This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The nuclear danger can be reduced by a system for global management, protection, control, and accounting as part of an international regime for nuclear materials. The development of an international fissile material management and control regime requires conceptual research supported by an analytical and modeling tool which treats the nuclear fuel cycle as a complete system. The prototype model developed visually represents the fundamental data, information, and capabilities related to the nuclear fuel cycle in a framework supportive of national or an international perspective. This includes an assessment of the global distribution of military and civilian fissile material inventories, a representation of the proliferation pertinent physical processes, facility specific geographic identification, and the capability to estimate resource requirements for the management and control of nuclear material. The model establishes the foundation for evaluating the global production, disposition, and safeguards and security requirements for fissile nuclear material and supports the development of other pertinent algorithmic capabilities necessary to undertake further global nuclear material related studies
THE BINARY BLACK HOLE MODEL FOR MRK 231 BITES THE DUST
Energy Technology Data Exchange (ETDEWEB)
Leighly, Karen M. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Terndrup, Donald M. [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Gallagher, Sarah C. [Department of Physics and Astronomy and Centre for Planetary and Space Exploration, The University of Western Ontario, London, ON N6A 3K7 (Canada); Lucy, Adrian B. [Department of Astronomy, Columbia University, 550 W. 120th Street, New York, NY 10027 (United States)
2016-09-20
Mrk 231 is a nearby quasar with an unusually red near-UV-to-optical continuum, generally explained as heavy reddening by dust. Yan et al. proposed that Mrk 231 is a milliparsec black hole binary with little intrinsic reddening. We show that if the observed FUV continuum is intrinsic, as assumed by Yan et al., it fails by a factor of about 100 in powering the observed strength of the near-infrared emission lines and the thermal near and mid-infrared continuum. In contrast, the line and continuum strengths are typical for a reddened AGN spectral energy distribution (SED). We find that the He i*/P β ratio is sensitive to the SED for a one-zone model. If this sensitivity is maintained in general broadline region models, then this ratio may prove a useful diagnostic for heavily reddened quasars. Analysis of archival Hubble Space Telescope STIS and Faint Object Camera data revealed evidence that the far-UV continuum emission is resolved on size scales of ∼40 pc. The lack of broad absorption lines in the far-UV continuum might be explained if it were not coincident with the central engine. One possibility is that it is the central engine continuum reflected from the receding wind on the far side of the quasar.
Predicting the "graduate on time (GOT)" of PhD students using binary logistics regression model
Shariff, S. Sarifah Radiah; Rodzi, Nur Atiqah Mohd; Rahman, Kahartini Abdul; Zahari, Siti Meriam; Deni, Sayang Mohd
2016-10-01
Malaysian government has recently set a new goal to produce 60,000 Malaysian PhD holders by the year 2023. As a Malaysia's largest institution of higher learning in terms of size and population which offers more than 500 academic programmes in a conducive and vibrant environment, UiTM has taken several initiatives to fill up the gap. Strategies to increase the numbers of graduates with PhD are a process that is challenging. In many occasions, many have already identified that the struggle to get into the target set is even more daunting, and that implementation is far too ideal. This has further being progressing slowly as the attrition rate increases. This study aims to apply the proposed models that incorporates several factors in predicting the number PhD students that will complete their PhD studies on time. Binary Logistic Regression model is proposed and used on the set of data to determine the number. The results show that only 6.8% of the 2014 PhD students are predicted to graduate on time and the results are compared wih the actual number for validation purpose.
Bond graph modeling of nuclear reactor dynamics
International Nuclear Information System (INIS)
Tylee, J.L.
1981-01-01
A tenth-order linear model of a pressurized water reactor (PWR) is developed using bond graph techniques. The model describes the nuclear heat generation process and the transfer of this heat to the reactor coolant. Comparisons between the calculated model response and test data from a small-scale PWR show the model to be an adequate representation of the actual plant dynamics. Possible application of the model in an advanced plant diagnostic system is discussed
Multifrequency Behaviour of the Gamma-Ray Binary System PSR B1259-63: Modelling the FERMI Flare
Directory of Open Access Journals (Sweden)
Brian van Soelen
2014-12-01
Full Text Available This paper presents a brief overview of the multifrequency properties of the gamma-ray binary system PSR B1259-63 from radio to very high energy gamma-rays. A summary is also presented of the various models put forward to explain the Fermi "flare" detected in 2011. Initial results are presented of a new turbulence driven model to explain the GeV observations.
Exact results in a lattice model of a binary reactant mixture
International Nuclear Information System (INIS)
Thomas, P.B.
1995-01-01
We study phase separation in a binary mixture of two particles, which can react with each other and form a third compound. We determine the exact phase boundaries for a restricted range of the interaction parameters
Energy Technology Data Exchange (ETDEWEB)
Nusbaumer, O. P. M
2007-07-01
This study is concerned with the quantification of Probabilistic Risk Assessment (PRA) using linked Fault Tree (FT) models. Probabilistic Risk assessment (PRA) of Nuclear Power Plants (NPPs) complements traditional deterministic analysis; it is widely recognized as a comprehensive and structured approach to identify accident scenarios and to derive numerical estimates of the associated risk levels. PRA models as found in the nuclear industry have evolved rapidly. Increasingly, they have been broadly applied to support numerous applications on various operational and regulatory matters. Regulatory bodies in many countries require that a PRA be performed for licensing purposes. PRA has reached the point where it can considerably influence the design and operation of nuclear power plants. However, most of the tools available for quantifying large PRA models are unable to produce analytically correct results. The algorithms of such quantifiers are designed to neglect sequences when their likelihood decreases below a predefined cutoff limit. In addition, the rare event approximation (e.g. Moivre's equation) is typically implemented for the first order, ignoring the success paths and the possibility that two or more events can occur simultaneously. This is only justified in assessments where the probabilities of the basic events are low. When the events in question are failures, the first order rare event approximation is always conservative, resulting in wrong interpretation of risk importance measures. Advanced NPP PRA models typically include human errors, common cause failure groups, seismic and phenomenological basic events, where the failure probabilities may approach unity, leading to questionable results. It is accepted that current quantification tools have reached their limits, and that new quantification techniques should be investigated. A novel approach using the mathematical concept of Binary Decision Diagram (BDD) is proposed to overcome these
DEPENDENCE OF X-RAY BURST MODELS ON NUCLEAR REACTION RATES
Energy Technology Data Exchange (ETDEWEB)
Cyburt, R. H.; Keek, L.; Schatz, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Amthor, A. M. [Department of Physics and Astronomy, Bucknell University, Lewisburg, PA 17837 (United States); Heger, A.; Meisel, Z.; Smith, K. [Joint Institute for Nuclear Astrophysics (JINA), Michigan State University, East Lansing, MI 48824 (United States); Johnson, E. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
2016-10-20
X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars, and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p, γ ), ( α , γ ), and ( α , p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the Kepler stellar evolution code. All relevant reaction rates on neutron-deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 changes in reaction rate with the highest impact were then repeated in the 1D multi-zone model. We find a number of uncertain reaction rates that affect predictions of light curves and burst ashes significantly. The results provide insights into the nuclear processes that shape observables from X-ray bursts, and guidance for future nuclear physics work to reduce nuclear uncertainties in X-ray burst models.
Jaubert, Jean-Noël; Privat, Romain
2014-01-01
The double-tangent construction of coexisting phases is an elegant approach to visualize all the multiphase binary systems that satisfy the equality of chemical potentials and to select the stable state. In this paper, we show how to perform the double-tangent construction of coexisting phases for binary systems modeled with the gamma-phi…
Canary, Jana D; Blizzard, Leigh; Barry, Ronald P; Hosmer, David W; Quinn, Stephen J
2016-05-01
Generalized linear models (GLM) with a canonical logit link function are the primary modeling technique used to relate a binary outcome to predictor variables. However, noncanonical links can offer more flexibility, producing convenient analytical quantities (e.g., probit GLMs in toxicology) and desired measures of effect (e.g., relative risk from log GLMs). Many summary goodness-of-fit (GOF) statistics exist for logistic GLM. Their properties make the development of GOF statistics relatively straightforward, but it can be more difficult under noncanonical links. Although GOF tests for logistic GLM with continuous covariates (GLMCC) have been applied to GLMCCs with log links, we know of no GOF tests in the literature specifically developed for GLMCCs that can be applied regardless of link function chosen. We generalize the Tsiatis GOF statistic originally developed for logistic GLMCCs, (TG), so that it can be applied under any link function. Further, we show that the algebraically related Hosmer-Lemeshow (HL) and Pigeon-Heyse (J(2) ) statistics can be applied directly. In a simulation study, TG, HL, and J(2) were used to evaluate the fit of probit, log-log, complementary log-log, and log models, all calculated with a common grouping method. The TG statistic consistently maintained Type I error rates, while those of HL and J(2) were often lower than expected if terms with little influence were included. Generally, the statistics had similar power to detect an incorrect model. An exception occurred when a log GLMCC was incorrectly fit to data generated from a logistic GLMCC. In this case, TG had more power than HL or J(2) . © 2015 John Wiley & Sons Ltd/London School of Economics.
Average Nuclear properties based on statistical model
International Nuclear Information System (INIS)
El-Jaick, L.J.
1974-01-01
The rough properties of nuclei were investigated by statistical model, in systems with the same and different number of protons and neutrons, separately, considering the Coulomb energy in the last system. Some average nuclear properties were calculated based on the energy density of nuclear matter, from Weizsscker-Beth mass semiempiric formulae, generalized for compressible nuclei. In the study of a s surface energy coefficient, the great influence exercised by Coulomb energy and nuclear compressibility was verified. For a good adjust of beta stability lines and mass excess, the surface symmetry energy were established. (M.C.K.) [pt
Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases
International Nuclear Information System (INIS)
Adjanor, G.
2007-11-01
Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)
A Neutron Star-White Dwarf Binary Model for Repeating Fast Radio Burst 121102
Gu, Wei-Min; Dong, Yi-Ze; Liu, Tong; Ma, Renyi; Wang, Junfeng
2016-06-01
We propose a compact binary model for the fast radio burst (FRB) repeaters, where the system consists of a magnetic white dwarf (WD) and a neutron star (NS) with strong bipolar magnetic fields. When the WD fills its Roche lobe, mass transfer will occur from the WD to the NS through the inner Lagrange point. The accreted magnetized materials may trigger magnetic reconnection when they approach the NS surface, and therefore the electrons can be accelerated to an ultra-relativistic speed. In this scenario, the curvature radiation of the electrons moving along the NS magnetic field lines can account for the characteristic frequency and the timescale of an FRB. Owing to the conservation of angular momentum, the WD may be kicked away after a burst, and the next burst may appear when the system becomes semi-detached again through the gravitational radiation. By comparing our analyses with the observations, we show that such an intermittent Roche-lobe overflow mechanism can be responsible for the observed repeating behavior of FRB 121102.
Tidal heating and mass loss in neutron star binaries - Implications for gamma-ray burst models
Meszaros, P.; Rees, M. J.
1992-01-01
A neutron star in a close binary orbit around another neutron star (or stellar-mass black hole) spirals inward owing to gravitational radiation. We discuss the effects of tidal dissipation during this process. Tidal energy dissipated in the neutron star's core escapes mainly as neutrinos, but heating of the crust, and outward diffusion of photons, blows off the outer layers of the star. This photon-driven mass loss precedes the final coalescence. The presence of this eject material impedes the escape of gamma-rays created via neutrino interactions. If an e(+) - e(-) fireball, created in the late stages of coalescence, were loaded with (or surrounded by) material with the mean column density of the ejecta, it could not be an efficient source of gamma-rays. Models for cosmologically distant gamma-rays burst that involve neutron stars must therefore be anisotropic, so that the fireball expands preferentially in directions where the column density of previously blown-off material is far below the spherically averaged value which we have calculated. Some possible 'scenarios' along these lines are briefly discussed.
Oktaviana, P. P.; Fithriasari, K.
2018-04-01
Mostly Indonesian citizen consume vannamei shrimp as their food. Vannamei shrimp also is one of Indonesian exports comodities mainstay. Vannamei shrimp in the ponds and markets could be contaminated by Salmonella sp bacteria. This bacteria will endanger human health. Salmonella sp bacterial contamination on vannamei shrimp could be affected by many factors. This study is intended to identify what factors that supposedly influence the Salmonella sp bacterial contamination on vannamei shrimp. The researchers used the testing result of Salmonella sp bacterial contamination on vannamei shrimp as response variable. This response variable has two categories: 0 = if testing result indicate that there is no Salmonella sp on vannamei shrimp; 1 = if testing result indicate that there is Salmonella sp on vannamei shrimp. There are four factors that supposedly influence the Salmonella sp bacterial contamination on vannamei shrimp, which are the testing result of Salmonella sp bacterial contamination on farmer hand swab; the subdistrict of vannamei shrimp ponds; the fish processing unit supplied by; and the pond are in hectare. This four factors used as predictor variables. The analysis used is Binary Logit Model Approach according to the response variable that has two categories. The analysis result indicates that the factors or predictor variables which is significantly affect the Salmonella sp bacterial contamination on vannamei shrimp are the testing result of Salmonella sp bacterial contamination on farmer hand swab and the subdistrict of vannamei shrimp ponds.
International Nuclear Information System (INIS)
Swaminathan, Srinivasan; Spiegel, Michael
2007-01-01
Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot dip galvanizing. In order to understand the influence of common alloying elements on the surface chemistry after annealing, model alloys of binary (Fe-2Si, Fe-2Mn and Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr and Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were investigated. The specimens were annealed for 60 s at 820 deg. C in N 2 -5% H 2 gas atmospheres with different dew points -80 and -40 deg. C, respectively. Surface chemistry of the annealed specimens was obtained by using X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) was used to view surface morphology. At low dew point -80 deg. C, apart from the thermodynamical calculations such as solubility product of oxides and their critical solute concentrations, kinetics play a decisive role on the selective oxidation, i.e. oxygen competition. As expected, the amount of external selective oxidation of alloying elements are well pronounced at higher dew point -40 deg. C. An attempt has been made to explain the dominant process of Si and Mn on Cr-oxidation and segregation. It is observed that annealing of quarternary system at higher dew point shifts the Cr-oxidation from external to internal
Sze, N N; Wong, S C; Lee, C Y
2014-12-01
In past several decades, many countries have set quantified road safety targets to motivate transport authorities to develop systematic road safety strategies and measures and facilitate the achievement of continuous road safety improvement. Studies have been conducted to evaluate the association between the setting of quantified road safety targets and road fatality reduction, in both the short and long run, by comparing road fatalities before and after the implementation of a quantified road safety target. However, not much work has been done to evaluate whether the quantified road safety targets are actually achieved. In this study, we used a binary logistic regression model to examine the factors - including vehicle ownership, fatality rate, and national income, in addition to level of ambition and duration of target - that contribute to a target's success. We analyzed 55 quantified road safety targets set by 29 countries from 1981 to 2009, and the results indicate that targets that are in progress and with lower level of ambitions had a higher likelihood of eventually being achieved. Moreover, possible interaction effects on the association between level of ambition and the likelihood of success are also revealed. Copyright © 2014 Elsevier Ltd. All rights reserved.
Revising the Model of Eclipsing Binary Stars for the Kepler Era
Prsa, Andrej
2010-01-01
The French-led mission CoRoT (Baglin et al. 2007) and NASA's Kepler mission (Borucki et al. 2007) have achieved unprecedented photometric accuracy, enabling us to glean stellar variability on scales that have yet to be understood. To employ the full power of eclipsing binary models requires substantial revision of the currently available codes such as WD (Wilson & Devinney 1971) or PHOEBE (Prsa & Zwitter 2005). One of the most important aspects of theoretical light curve computation is stellar surface discretization. Until now, surface elements were determined by equidistant partitioning along co-latitude and longitude; this scheme is inefficient and produces numerical artifacts when stellar distortion is significant (i.e. semi-detached and overcontact systems). In its place we propose a method that relies on equidistant partitioning along equipotentials. This way surface elements cover the stars most uniformly. We further propose two alternatives for the starting vertex of discretization: the stellar pole and the back radius. The partitioning method with both alternatives is explained in detail and differences from the original scheme are discussed.
Energy Technology Data Exchange (ETDEWEB)
Swaminathan, Srinivasan [High Temperature Reactions Group, Department of Interface Chemistry and Surface Engineering, Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany)]. E-mail: s.swaminathan@mpie.de; Spiegel, Michael [High Temperature Reactions Group, Department of Interface Chemistry and Surface Engineering, Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany)
2007-03-15
Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot dip galvanizing. In order to understand the influence of common alloying elements on the surface chemistry after annealing, model alloys of binary (Fe-2Si, Fe-2Mn and Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr and Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were investigated. The specimens were annealed for 60 s at 820 deg. C in N{sub 2}-5% H{sub 2} gas atmospheres with different dew points -80 and -40 deg. C, respectively. Surface chemistry of the annealed specimens was obtained by using X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) was used to view surface morphology. At low dew point -80 deg. C, apart from the thermodynamical calculations such as solubility product of oxides and their critical solute concentrations, kinetics play a decisive role on the selective oxidation, i.e. oxygen competition. As expected, the amount of external selective oxidation of alloying elements are well pronounced at higher dew point -40 deg. C. An attempt has been made to explain the dominant process of Si and Mn on Cr-oxidation and segregation. It is observed that annealing of quarternary system at higher dew point shifts the Cr-oxidation from external to internal.
A NEUTRON STAR–WHITE DWARF BINARY MODEL FOR REPEATING FAST RADIO BURST 121102
International Nuclear Information System (INIS)
Gu, Wei-Min; Dong, Yi-Ze; Liu, Tong; Ma, Renyi; Wang, Junfeng
2016-01-01
We propose a compact binary model for the fast radio burst (FRB) repeaters, where the system consists of a magnetic white dwarf (WD) and a neutron star (NS) with strong bipolar magnetic fields. When the WD fills its Roche lobe, mass transfer will occur from the WD to the NS through the inner Lagrange point. The accreted magnetized materials may trigger magnetic reconnection when they approach the NS surface, and therefore the electrons can be accelerated to an ultra-relativistic speed. In this scenario, the curvature radiation of the electrons moving along the NS magnetic field lines can account for the characteristic frequency and the timescale of an FRB. Owing to the conservation of angular momentum, the WD may be kicked away after a burst, and the next burst may appear when the system becomes semi-detached again through the gravitational radiation. By comparing our analyses with the observations, we show that such an intermittent Roche-lobe overflow mechanism can be responsible for the observed repeating behavior of FRB 121102.
A NEUTRON STAR–WHITE DWARF BINARY MODEL FOR REPEATING FAST RADIO BURST 121102
Energy Technology Data Exchange (ETDEWEB)
Gu, Wei-Min; Dong, Yi-Ze; Liu, Tong; Ma, Renyi; Wang, Junfeng, E-mail: guwm@xmu.edu.cn [Department of Astronomy, Xiamen University, Xiamen, Fujian 361005 (China)
2016-06-01
We propose a compact binary model for the fast radio burst (FRB) repeaters, where the system consists of a magnetic white dwarf (WD) and a neutron star (NS) with strong bipolar magnetic fields. When the WD fills its Roche lobe, mass transfer will occur from the WD to the NS through the inner Lagrange point. The accreted magnetized materials may trigger magnetic reconnection when they approach the NS surface, and therefore the electrons can be accelerated to an ultra-relativistic speed. In this scenario, the curvature radiation of the electrons moving along the NS magnetic field lines can account for the characteristic frequency and the timescale of an FRB. Owing to the conservation of angular momentum, the WD may be kicked away after a burst, and the next burst may appear when the system becomes semi-detached again through the gravitational radiation. By comparing our analyses with the observations, we show that such an intermittent Roche-lobe overflow mechanism can be responsible for the observed repeating behavior of FRB 121102.
Empirical tests of pre-main-sequence stellar evolution models with eclipsing binaries
Stassun, Keivan G.; Feiden, Gregory A.; Torres, Guillermo
2014-06-01
We examine the performance of standard pre-main-sequence (PMS) stellar evolution models against the accurately measured properties of a benchmark sample of 26 PMS stars in 13 eclipsing binary (EB) systems having masses 0.04-4.0 M⊙ and nominal ages ≈1-20 Myr. We provide a definitive compilation of all fundamental properties for the EBs, with a careful and consistent reassessment of observational uncertainties. We also provide a definitive compilation of the various PMS model sets, including physical ingredients and limits of applicability. No set of model isochrones is able to successfully reproduce all of the measured properties of all of the EBs. In the H-R diagram, the masses inferred for the individual stars by the models are accurate to better than 10% at ≳1 M⊙, but below 1 M⊙ they are discrepant by 50-100%. Adjusting the observed radii and temperatures using empirical relations for the effects of magnetic activity helps to resolve the discrepancies in a few cases, but fails as a general solution. We find evidence that the failure of the models to match the data is linked to the triples in the EB sample; at least half of the EBs possess tertiary companions. Excluding the triples, the models reproduce the stellar masses to better than ∼10% in the H-R diagram, down to 0.5 M⊙, below which the current sample is fully contaminated by tertiaries. We consider several mechanisms by which a tertiary might cause changes in the EB properties and thus corrupt the agreement with stellar model predictions. We show that the energies of the tertiary orbits are comparable to that needed to potentially explain the scatter in the EB properties through injection of heat, perhaps involving tidal interaction. It seems from the evidence at hand that this mechanism, however it operates in detail, has more influence on the surface properties of the stars than on their internal structure, as the lithium abundances are broadly in good agreement with model predictions. The
Modeling the Nuclear Fuel Cycle
International Nuclear Information System (INIS)
Jacobson, Jacob J.; Dunzik-Gougar, Mary Lou; Juchau, Christopher A.
2010-01-01
A review of existing nuclear fuel cycle systems analysis codes was performed to determine if any existing codes meet technical and functional requirements defined for a U.S. national program supporting the global and domestic assessment, development and deployment of nuclear energy systems. The program would be implemented using an interconnected architecture of different codes ranging from the fuel cycle analysis code, which is the subject of the review, to fundamental physical and mechanistic codes. Four main functions are defined for the code: (1) the ability to characterize and deploy individual fuel cycle facilities and reactors in a simulation, while discretely tracking material movements, (2) the capability to perform an uncertainty analysis for each element of the fuel cycle and an aggregate uncertainty analysis, (3) the inclusion of an optimization engine able to optimize simultaneously across multiple objective functions, and (4) open and accessible code software and documentation to aid in collaboration between multiple entities and facilitate software updates. Existing codes, categorized as annualized or discrete fuel tracking codes, were assessed according to the four functions and associated requirements. These codes were developed by various government, education and industrial entities to fulfill particular needs. In some cases, decisions were made during code development to limit the level of detail included in a code to ease its use or to focus on certain aspects of a fuel cycle to address specific questions. The review revealed that while no two of the codes are identical, they all perform many of the same basic functions. No code was able to perform defined function 2 or several requirements of functions 1 and 3. Based on this review, it was concluded that the functions and requirements will be met only with development of a new code, referred to as GENIUS.
International Nuclear Information System (INIS)
Almasi, Mohammad
2013-01-01
Densities and viscosities for binary mixtures of dimethyl carbonate with 2-propanol up to 2-heptanol were measured at various temperatures and ambient pressure. From experimental data, excess molar volumes, V m E . were calculated and correlated by the Redlich–Kister equation to obtain the binary coefficients and the standard deviations. Excess molar volumes, V m E , are positive for all studied mixtures over the entire range of the mole fraction. The ERAS-model has been applied for describing the binary excess molar volumes and also Peng–Robinson–Stryjek–Vera (PRSV) equation of state (EOS) has been used to predict the binary excess molar volumes and viscosities. Also several semi-empirical models were used to correlate the viscosity of binary mixtures
Time evolution of a quenched binary alloy: computer simulation of a three-dimensional model system
International Nuclear Information System (INIS)
Marro, J.; Bortz, A.B.; Kalos, M.H.; Lebowitz, J.L.; Sur, A.
1976-01-01
Results are presented of computer simulation of the time evolution for a model of a binary alloy, such as ZnAl, following quenching. The model system is a simple cubic lattice the sites of which are occupied either by A or B particles. There is a nearest neighbor interaction favoring segregation into an A rich and a B rich phase at low temperatures, T less than T/sub c/. Starting from a random configuration, T much greater than T/sub c/, the system is quenched to and evolves at a temperature T less than T/sub c/. The evolution takes place through exchanges between A and B atoms on nearest neighbor sites. The probability of such an exchange is assumed proportional to e/sup -βΔU/ [1 + e/sup -βΔU/] -1 where β = (k/sub B/T) -1 and ΔU is the change in energy resulting from the exchange. In the simulations either a 30 x 30 x 30 or a 50 x 50 x 50 lattice is used with various fractions of the sites occupied by A particles. The evolution of the Fourier transform of the spherically averaged structure function S(k,t), the energy, and the cluster distribution were computed. Comparison is made with various theories of this process and with some experiments. It is found in particular that the results disagree with the predictions of the linearized Cahn-Hilliard theory of spinodal decomposition. The qualitative form of the results appear to be unaffected if the change in the positions of the atoms takes place via a vacancy mechanism rather than through direct exchanges
Shore, S N; van den Heuvel, EPJ
1994-01-01
This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.
The nuclear Thomas-Fermi model
International Nuclear Information System (INIS)
Myers, W.D.; Swiatecki, W.J.
1994-08-01
The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from 82 Sn to 170 Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z 2 /A exceeds about 100
The Nuclear Thomas-Fermi Model
Myers, W. D.; Swiatecki, W. J.
1994-08-01
The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from {sup 82}Sn to {sup 170}Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z{sup 2}/A exceeds about 100.
Nuclear power investment risk economic model
International Nuclear Information System (INIS)
Postula, F.D.; Houghton, W.J.
1986-01-01
This paper describes the economic model which was developed to evaluate the net costs incurred by an owner due to an accident induced outage at a nuclear power plant. During such an outage, the portion of the plant operating costs associated with power production are saved; however the owner faces a sizable expense as fossil fuels are burned as a substitute for power from the incapacitated nuclear plant. Additional expenses are incurred by the owner for plant repair and, if necessary, decontamination cost. The model makes provision for mitigating these costs by sales of power, property damage insurance payments, tax write-offs and increased rates
Calculation models for a nuclear reactor
International Nuclear Information System (INIS)
Tashanii, Ahmed Ali
2010-01-01
Determination of different parameters of nuclear reactors requires neutron transport calculations. Due to complicity of geometry and material composition of the reactor core, neutron calculations were performed for simplified models of the real arrangement. In frame of the present work two models were used for calculations. First, an elementary cell model was used to prepare cross section data set for a homogenized-core reactor model. The homogenized-core reactor model was then used to perform neutron transport calculation. The nuclear reactor is a tank-shaped thermal reactor. The semi-cylindrical core arrangement consists of aluminum made fuel bundles immersed in water which acts as a moderator as well as a coolant. Each fuel bundle consists of aluminum cladded fuel rods arranged in square lattices. (author)
THE PERIOD VARIATION OF AND A SPOT MODEL FOR THE ECLIPSING BINARY AR BOOTIS
International Nuclear Information System (INIS)
Lee, Jae Woo; Youn, Jae-Hyuck; Lee, Chung-Uk; Kim, Seung-Lee; Koch, Robert H.
2009-01-01
New CCD photometric observations of the eclipsing system AR Boo were obtained from 2006 February to 2008 April. The star's photometric properties are derived from detailed studies of the period variability and of all available light curves. We find that over about 56 yr the orbital period of the system has varied due to a combination of an upward parabola and a sinusoid rather than in a monotonic fashion. Mass transfer from the less massive primary to the more massive secondary component is likely responsible for at least a significant part of the secular period change. The cyclical variation with a period of 7.57 yr and a semi-amplitude of 0.0015 d can be produced either by a light-travel-time effect due to an unseen companion with a scaled mass of M 3 sin i 3 = 0.081 M sun or by a magnetic period modulation in the secondary star. Historical light curves of AR Boo, as well as our own, display season-to-season light variability, which are best modeled by including both a cool spot and a hot one on the secondary star. We think that the spots express magnetic dynamo-related activity and offer limited support for preferring the magnetic interpretation of the 7.57 yr cycle over the third-body interpretation. Our solutions confirm that AR Boo belongs to the W-subtype contact binary class, consisting of a hotter, less massive primary star with a spectral type of G9 and a companion of spectral type K1.
The transition model test for serial dependence in mixed-effects models for binary data
DEFF Research Database (Denmark)
Breinegaard, Nina; Rabe-Hesketh, Sophia; Skrondal, Anders
2017-01-01
Generalized linear mixed models for longitudinal data assume that responses at different occasions are conditionally independent, given the random effects and covariates. Although this assumption is pivotal for consistent estimation, violation due to serial dependence is hard to assess by model...
Jana, Amiya Kumar; Ganguly, Saibal; Samanta, Amar Nath
2006-10-01
The work is devoted to design the globally linearizing control (GLC) strategy for a multicomponent distillation process. The control system is comprised with a nonlinear transformer, a nonlinear closed-loop state estimator [extended Kalman filter (EKF)], and a linear external controller [conventional proportional integral (PI) controller]. The model of a binary distillation column has been used as a state predictor to avoid huge design complexity of the EKF estimator. The binary components are the light key and the heavy key of the multicomponent system. The proposed GLC-EKF (GLC in conjunction with EKF) control algorithm has been compared with the GLC-ROOLE [GLC coupled with reduced-order open-loop estimator (ROOLE)] and the dual-loop PI controller based on set point tracking and disturbance rejection performance. Despite huge process/predictor mismatch, the superiority of the GLC-EKF has been inspected over the GLC-ROOLE control structure.
A new model for nuclear matter
International Nuclear Information System (INIS)
Skyrme, T.H.R.
1994-01-01
The different values obtained for nuclear radii from electromagnetic interactions as compared with specifically nuclear interactions suggested a model of nuclear matter in which the meson field is supposed to condense into an incompressible fluid and the nucleonic sources are confined to its interior by a strong interaction between the sources and the fluid as a whole. The sources are also coupled to spin and charge fluctuations in the fluid, whose exchange leads to further internucleonic forces. It is necessary to postulate that the fluid have a comparatively low density; as a result rotational levels of the fluid are high, leading to a small probability of exchange of angular momentum (and charge coupled to it) with the sources. The values of the anomalous electrical interactions of nucleons deduced are in rough agreement with the facts. The nuclear structure indicated is a shell model embedded in the mesic fluid whose oscillations, strongly coupled to the nucleons, give rise to the collective features of nuclear structure as in the theory of Bohr and Mottelson. It is suggested that this picture of the mesic field may indicate where to look for solutions of the meson field equations. (author). 9 refs
Organizational model of the nuclear sector
International Nuclear Information System (INIS)
Metri, Paulo
2015-01-01
The Brazilian Constitution prohibits private investment in many activities of the Nuclear Industry. Right now, it is in progress a constitutional amendment that allows private companies to build and operate nuclear power plants of its own. This work rescues the historical reasons that led the Congress of 1988 to choose the State owned model for this sector. In addition, the arguments that are used to propose the present changes are repeated here. As indicated in INAC 2015 website, 'sustainable development is supported by three pillars: social, economic and environmental'. Thus, the organizational model to be adopted for the Nuclear Sector must meet these requirements. The official objectives of the energy sector, as set out in the law 9,478, are remembered. New objectives, better established, and also adapted to the electrical subsector, are shown. Besides the use of these objectives to choose the sources and related technologies for the electric generation, they also can be used as evaluation criteria to help in the decision process of the organizational model for the Nuclear Sector. Acting in this way, it is ensured that social, economic and environmental requirements are being attended. Finally, if the developed evaluation criteria are applied, the impacts of each organizational model can be analyzed and preliminary conclusion and recommendation can be made. (author)
Transient analysis models for nuclear power plants
International Nuclear Information System (INIS)
Agapito, J.R.
1981-01-01
The modelling used for the simulation of the Angra-1 start-up reactor tests, using the RETRAN computer code is presented. Three tests are simulated: a)nuclear power plant trip from 100% of power; b)great power excursions tests and c)'load swing' tests.(E.G.) [pt
Organizational model of the nuclear sector
Energy Technology Data Exchange (ETDEWEB)
Metri, Paulo, E-mail: pmetri@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN/CGRC), Rio de Janeiro, RJ (Brazil)
2015-07-01
The Brazilian Constitution prohibits private investment in many activities of the Nuclear Industry. Right now, it is in progress a constitutional amendment that allows private companies to build and operate nuclear power plants of its own. This work rescues the historical reasons that led the Congress of 1988 to choose the State owned model for this sector. In addition, the arguments that are used to propose the present changes are repeated here. As indicated in INAC 2015 website, 'sustainable development is supported by three pillars: social, economic and environmental'. Thus, the organizational model to be adopted for the Nuclear Sector must meet these requirements. The official objectives of the energy sector, as set out in the law 9,478, are remembered. New objectives, better established, and also adapted to the electrical subsector, are shown. Besides the use of these objectives to choose the sources and related technologies for the electric generation, they also can be used as evaluation criteria to help in the decision process of the organizational model for the Nuclear Sector. Acting in this way, it is ensured that social, economic and environmental requirements are being attended. Finally, if the developed evaluation criteria are applied, the impacts of each organizational model can be analyzed and preliminary conclusion and recommendation can be made. (author)
Conservation laws and nuclear transport models
International Nuclear Information System (INIS)
Gale, C.; Das Gupta, S.
1990-01-01
We discuss the consequences of energy and angular momentum conservation for nucleon-nucleon scattering in a nuclear environment during high-energy heavy-ion collisions. We describe algorithms that ensure stricter enforcement of such conservation laws within popular microscopic models of intermediate-energy heavy-ion collisions. We find that the net effects on global observables are small
The True Ultracool Binary Fraction Using Spectral Binaries
Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Schmidt, Sarah J.; Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle; Gelino, Chris
2018-01-01
Brown dwarfs bridge the gap between stars and giant planets. While the essential mechanisms governing their formation are not well constrained, binary statistics are a direct outcome of the formation process, and thus provide a means to test formation theories. Observational constraints on the brown dwarf binary fraction place it at 10 ‑ 20%, dominated by imaging studies (85% of systems) with the most common separation at 4 AU. This coincides with the resolution limit of state-of-the-art imaging techniques, suggesting that the binary fraction is underestimated. We have developed a separation-independent method to identify and characterize tightly-separated (dwarfs as spectral binaries by identifying traces of methane in the spectra of late-M and early-L dwarfs. Imaging follow-up of 17 spectral binaries yielded 3 (18%) resolved systems, corroborating the observed binary fraction, but 5 (29%) known binaries were missed, reinforcing the hypothesis that the short-separation systems are undercounted. In order to find the true binary fraction of brown dwarfs, we have compiled a volume-limited, spectroscopic sample of M7-L5 dwarfs and searched for T dwarf companions. In the 25 pc volume, 4 candidates were found, three of which are already confirmed, leading to a spectral binary fraction of 0.95 ± 0.50%, albeit for a specific combination of spectral types. To extract the true binary fraction and determine the biases of the spectral binary method, we have produced a binary population simulation based on different assumptions of the mass function, age distribution, evolutionary models and mass ratio distribution. Applying the correction fraction resulting from this method to the observed spectral binary fraction yields a true binary fraction of 27 ± 4%, which is roughly within 1σ of the binary fraction obtained from high resolution imaging studies, radial velocity and astrometric monitoring. This method can be extended to identify giant planet companions to young brown
Modeling and optimization of geothermal power plants using the binary fluid cycle
Energy Technology Data Exchange (ETDEWEB)
Walter, R.A.
1976-09-01
A computer simulation of a binary fluid cycle power plant for use with geothermal energy sources, and the subsequent optimization of this power plant type over a range of geothermal source conditions are described. The optimization technique employed for this analysis was based upon the principle of maximum use of geothermal energy.
Czech Academy of Sciences Publication Activity Database
Svoboda, Jiří; Gamsjäger, E.
2011-01-01
Roč. 102, č. 6 (2011), s. 666-673 ISSN 1862-5282 R&D Projects: GA MŠk(CZ) OC10029 Institutional research plan: CEZ:AV0Z20410507 Keywords : modelling * phase transformation * ediffusion Subject RIV: BJ - Thermodynamics Impact factor: 0.830, year: 2011
Scaling laws for modeling nuclear reactor systems
International Nuclear Information System (INIS)
Nahavandi, A.N.; Castellana, F.S.; Moradkhanian, E.N.
1979-01-01
Scale models are used to predict the behavior of nuclear reactor systems during normal and abnormal operation as well as under accident conditions. Three types of scaling procedures are considered: time-reducing, time-preserving volumetric, and time-preserving idealized model/prototype. The necessary relations between the model and the full-scale unit are developed for each scaling type. Based on these relationships, it is shown that scaling procedures can lead to distortion in certain areas that are discussed. It is advised that, depending on the specific unit to be scaled, a suitable procedure be chosen to minimize model-prototype distortion
Experimental test of nuclear magnetization distribution and nuclear structure models
International Nuclear Information System (INIS)
Beirsdorfer, P; Crespo-Lopez-Urrutia, J R; Utter, S B.
1999-01-01
Models exist that ascribe the nuclear magnetic fields to the presence of a single nucleon whose spin is not neutralized by pairing it up with that of another nucleon; other models assume that the generation of the magnetic field is shared among some or all nucleons throughout the nucleus. All models predict the same magnetic field external to the nucleus since this is an anchor provided by experiments. The models differ, however, in their predictions of the magnetic field arrangement within the nucleus for which no data exist. The only way to distinguish which model gives the correct description of the nucleus would be to use a probe inserted into the nucleus. The goal of our project was to develop exactly such a probe and to use it to measure fundamental nuclear quantities that have eluded experimental scrutiny. The need for accurately knowing such quantities extends far beyond nuclear physics and has ramifications in parity violation experiments on atomic traps and the testing of the standard model in elementary particle physics. Unlike scattering experiments that employ streams of free particles, our technique to probe the internal magnetic field distribution of the nucleus rests on using a single bound electron. Quantum mechanics shows that an electron in the innermost orbital surrounding the nucleus constantly dives into the nucleus and thus samples the fields that exist inside. This sampling of the nucleus usually results in only minute shifts in the electron s average orbital, which would be difficult to detect. By studying two particular energy states of the electron, we can, however, dramatically enhance the effects of the distribution of the magnetic fields in the nucleus. In fact about 2% of the energy difference between the two states, dubbed the hyperfine splitting, is determined by the effects related to the distribution of magnetic fields in the nucleus, A precise measurement of this energy difference (better than 0.01%) would then allow us to place
Model Action Plan for Nuclear Forensics and Nuclear Attribution
International Nuclear Information System (INIS)
Dudder, G B; Niemeyer, S; Smith, D K; Kristo, M J
2004-01-01
Nuclear forensics and nuclear attribution have become increasingly important tools in the fight against illegal trafficking in nuclear and radiological materials. This technical report documents the field of nuclear forensics and nuclear attribution in a comprehensive manner, summarizing tools and procedures that have heretofore been described independently in the scientific literature. This report also provides national policy-makers, decision-makers, and technical managers with guidance for responding to incidents involving the interdiction of nuclear and radiological materials. However, due to the significant capital costs of the equipment and the specialized expertise of the personnel, work in the field of nuclear forensics has been restricted so far to a handful of national and international laboratories. In fact, there are a limited number of specialists who have experience working with interdicted nuclear materials and affiliated evidence. Most of the laboratories that have the requisite equipment, personnel, and experience to perform nuclear forensic analysis are participants in the Nuclear Smuggling International Technical Working Group or ITWG (see Section 1.8). Consequently, there is a need to disseminate information on an appropriate response to incidents of nuclear smuggling, including a comprehensive approach to gathering evidence that meets appropriate legal standards and to developing insights into the source and routes of nuclear and radiological contraband. Appendix A presents a ''Menu of Options'' for other Member States to request assistance from the ITWG Nuclear Forensics Laboratories (INFL) on nuclear forensic cases
Directory of Open Access Journals (Sweden)
A. C. D. Freitas
2013-03-01
Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.
International Nuclear Information System (INIS)
Bianchi, M.P.
1991-01-01
The discrete Boltzmann equation is a mathematical model in the kinetic theory of gases which defines the time and space evolution of a system of gas particles with a finite number of selected velocities. Discrete kinetic theory is an interesting field of research in mathematical physics and applied mathematics for several reasons. One of the relevant fields of application of the discrete Boltzmann equation is the analysis of nonlinear shock wave phenomena. Here, a new multiple collision regular plane model for binary gas mixtures is proposed within the discrete theory of gases and applied to the analysis of the classical problems of shock wave propagation
Samadi Ghadim, A.; Lampens, P.; Jassur, M.
2018-03-01
The A-F-type stars and pulsators (δ Scuti-γ Dor) are in a critical regime where they experience a transition from radiative to convective transport of energy in their envelopes. Such stars can pulsate in both gravity and acoustic modes. Hence, the knowledge of their fundamental parameters along with their observed pulsation characteristics can help in improving the stellar models. When residing in a binary system, these pulsators provide more accurate and less model-dependent stellar parameters than in the case of their single counterparts. We present a light-curve model for the eclipsing system KIC 6048106 based on the Kepler photometry and the code PHOEBE. We aim to obtain accurate physical parameters and tough constraints for the stellar modelling of this intermediate-mass hybrid pulsator. We performed a separate modelling of three light-curve segments which show a distinct behaviour due to a difference in activity. We also analysed the Kepler Eclipse Time Variations (ETVs). KIC 6048106 is an Algol-type binary with F5-K5 components, a near-circular orbit and a 1.56-d period undergoing variations of the order of Δ P/P˜eq 3.60× 10^{-7} in 287 ± 7 d. The primary component is a main-sequence star with M1 = 1.55 ± 0.11 M⊙, R1 = 1.57 ± 0.12 R⊙. The secondary is a much cooler subgiant with M2 = 0.33 ± 0.07 M⊙, R2 = 1.77 ± 0.16 R⊙. Many small near-polar spots are active on its surface. The second quadrature phase shows a brightness modulation on a time-scale 290 ± 7 d, in good agreement with the ETV modulation. This study reveals a stable binary configuration along with clear evidence of a long-term activity of the secondary star.
Picker, K M; Bikane, F
2001-08-01
The aim of the study is to use the 3D modeling technique of compaction cycles for analysis of binary and ternary mixtures. Three materials with very different deformation and densification characteristics [cellulose acetate (CAC), dicalcium phosphate dihydrate (EM) and theophylline monohydrate (TM)] have been tableted at graded maximum relative densities (rhorel, max) on an eccentric tableting machine. Following that, graded binary mixtures from CAC and EM have been compacted. Finally, the same ratios of CAC and EM have been tableted in a ternary mixture with 20 vol% TM. All compaction cycles have been analyzed by using different data analysis methods. Three-dimensional modeling, conventional determination of the slope of the Heckel function, determination of the elastic recovery during decompression, and calculations according to the pressure-time function were the methods of choice. The results show that the 3D model technique is able to gain the information in one step instead of three different approaches, which is an advantage for formulation development. The results show that this model enables one to better distinguish the compaction properties of mixtures and the interaction of the components in the tablet than 2D models. Furthermore, the information by 3D modeling is more precise since in the slope K of the Heckel-plot (in die) elasticity is included, and in the parameters of the pressure-time function beta and gamma plastic deformation due to pressure is included. The influence of time and pressure on the displacement can now be differentiated.
International Nuclear Information System (INIS)
Larsson-Leander, G.
1979-01-01
Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)
International Nuclear Information System (INIS)
Yang, Yaoyao; Yang, Peng; Du, Shichao; Li, Kangli; Zhao, Kaifei; Xu, Shijie; Hou, Baohong; Gong, Junbo
2016-01-01
Highlights: • The solubility of allisartan isoproxil in binary solvent mixtures were determined. • Apelblat, CNIBS/R-K and Jouyban-Acree models were used to correlate the solubility. • Solubility parameter theory was used to explain the co-solvency phenomenon. • Regular mixing rules were used to calculate solubility parameter of binary solvents. • The mixing thermodynamics were calculated and discussed based on NRTL model. - Abstract: In this work, the solubility of allisartan isoproxil in binary solvent mixtures, including (acetone + water), (acetonitrile + water) and (methanol + water), was determined by a gravimetric method with the temperature ranging from (278.15 to 313.15) K at atmospheric pressure (p = 0.1 MPa). The solubility of allisartan isoproxil in three binary solvent mixtures all increased with the rising of temperature at a constant solvent composition. For the binary solvent mixtures of (methanol + water), the solubility increased with the increasing of methanol fraction, while it appeared maximum value at a certain solvent composition in the other two binary solvent mixtures (acetone + water and acetonitrile + water). Based on the theory of solubility parameter, Fedors method and two mixing rules were employed to calculate the solubility parameters, by which the proximity of solubility parameters between allisartan isoproxil and binary solvent mixtures explained the co-solvent phenomenon. Additionally, the modified Apelblat equation, CNIBS/R-K model and Jouyban-Acree model were used to correlate the solubility data in binary solvent mixtures, and it turned out that all the three correlation models could give a satisfactory result. Furthermore, the mixing thermodynamic properties were calculated based on NRTL model, which indicated that the mixing process was spontaneous and exothermic.
Directory of Open Access Journals (Sweden)
Mounir Mahmoud Moghazy Abdel-Aal
2017-12-01
Full Text Available In the travel demand modeling field, mode choice is the most important decision that affects the resulted road congestion. The behavioral nature of the disaggregate models and the associated advantages of such models over aggregate models have led to their extensive use. This paper proposes a framework to determine the value of time (VoT for the city of Alexandria through calibrating a disaggregate linear-in parameter utility-based binary logit mode choice model of the city. The mode attributes (travel time and travel cost along with traveler attributes (car ownership and income were selected as the utility attributes of the basic model formulation which included 5 models. Three additional alternative utility formulations based on the transformation of the mode attributes including relative travel cost (cost divided by income and log (travel time and the combination of the two transformations together were introduced. The parameter estimation procedure was based on the likelihood maximization technique and was performed in EXCEL. Out of 20 models estimated, only 2 models are considered successful in terms of the parameters estimates correct signs and the magnitude of their significance (t-statistics value. The determination of the VoT serves also in the model validation. The best two models estimated the value of time at LE 11.30/hr and LE 14.50/hr with a relative error of +3.7% and +33.0%, respectively, of the hourly salary of LE 10.9/hr. The proposed two models prove to be sensitive to trip time and income levels as factors affecting the choice mechanism. The sensitivity analysis was performed and proved the model with higher relative error is marginally more robust. Keywords: Transportation modeling, Binary mode choice, Parameter estimation, Value of time, Likelihood maximization, Sensitivity analysis
Pressurizer model for Embalse nuclear power plant
International Nuclear Information System (INIS)
Parkansky, D.G.; Bedrossian, G.C.
1993-01-01
Since the models normally used for he simulation of eventual accidents at the Embalse nuclear power plant with the FIREBIRD III code did not work satisfactorily when the pressurizer becomes empty of liquid, a new model was developed. This report presents the governing equations as well as the calculation technique, for which a computer program was made. An example of application is also presented. The results show that this new model can easily solve the problem of lack of liquid in the pressurizer, as it lets the fluid enter and exit freely, according to the pressure transient at the reactor outlet headers. (author)
Aasi, J.; Abbott, B. P.; Abbott, R.; Abernathy, M. R.; Adhikari, Rana X.; Anderson, R.; Anderson, S. B.; Arai, K.; Araya, M. C.; Austin, L.; Barayoga, J. C.; Barish, B. C.; Billingsley, G.; Black, E.; Blackburn, J. K.
2014-01-01
The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave (GW) astrophysics communities. The purpose of NINJA is to study the ability to detect GWs emitted from merging binary black holes (BBH) and recover their parameters with next-generation GW observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete BBH hybrid waveforms consisting of a numerical portion mo...
International Nuclear Information System (INIS)
Cokelaer, T
2007-01-01
Matched filtering is used to search for gravitational waves emitted by inspiralling compact binaries in data from ground-based interferometers. One of the key aspects of the detection process is the deployment of a set of templates, also called a template bank, to cover the astrophysically interesting region of the parameter space. In a companion paper, we described the template bank algorithm used in the analysis of Laser Interferometer Gravitational-Wave Observatory (LIGO) data to search for signals from non-spinning binaries made of neutron star and/or stellar-mass black holes; this template bank is based upon physical template families. In this paper, we describe the phenomenological template bank that was used to search for gravitational waves from non-spinning black hole binaries (from stellar mass formation) in the second, third and fourth LIGO science runs. We briefly explain the design of the bank, whose templates are based on a phenomenological detection template family. We show that this template bank gives matches greater than 95% with the physical template families that are expected to be captured by the phenomenological templates
Relativistic nuclear physics with the spectator model
International Nuclear Information System (INIS)
Gross, F.
1988-01-01
The spectator model, a general approach to the relativistic treatment of nuclear physics problems in which spectators to nuclear interactions are put on their mass-shell, will be defined nd described. The approach grows out of the relativistic treatment of two and three body systems in which one particle is off-shell, and recent numerical results for the NN interaction will be presented. Two meson-exchange models, one with only 4 mesons (π, σ, /rho/, ω) but with a 25% admixture of γ 5 coupling for the pion, and a second with 6 mesons (π, σ, /rho/, ω, δ, and /eta/) but a pure γ 5 γ/sup mu/ pion coupling, are shown to give very good quantitative fits to NN scattering phase shifts below 400 MeV, and also a good description of the /rho/ 40 Cα elastic scattering observables. 19 refs., 6 figs., 1 tab
Nuclear security assessment with Markov model approach
International Nuclear Information System (INIS)
Suzuki, Mitsutoshi; Terao, Norichika
2013-01-01
Nuclear security risk assessment with the Markov model based on random event is performed to explore evaluation methodology for physical protection in nuclear facilities. Because the security incidences are initiated by malicious and intentional acts, expert judgment and Bayes updating are used to estimate scenario and initiation likelihood, and it is assumed that the Markov model derived from stochastic process can be applied to incidence sequence. Both an unauthorized intrusion as Design Based Threat (DBT) and a stand-off attack as beyond-DBT are assumed to hypothetical facilities, and performance of physical protection and mitigation and minimization of consequence are investigated to develop the assessment methodology in a semi-quantitative manner. It is shown that cooperation between facility operator and security authority is important to respond to the beyond-DBT incidence. (author)
Model wells for nuclear well logging
International Nuclear Information System (INIS)
Tittle, C.W.
1989-01-01
Considerations needed in the design and construction of model wells for nuclear log calibration are covered, with special attention to neutron porosity logging and total γ-ray logging. Pulsed neutron decay-time and spectral γ-ray logging are discussed briefly. The American Petroleum Institute calibration facility for nuclear logs is a good starting point for similar or expanded facilities. A few of its shortcomings are mentioned; they are minor. The problem of fluid saturation is emphasized. Attention is given to models made of consolidated rock and those containing unconsolidated material such as Ottawa sand. Needed precautions are listed. A similarity method is presented for estimating the porosity index of formations that are not fully saturated. (author)
Belmiloudi , Aziz; Rasheed , Amer
2015-01-01
In this paper we propose a numerical scheme and perform its numerical analysis devoted to an anisotropic phase-field model with convection under the influence of magnetic field for the isother-mal solidification of binary mixtures in two-dimensional geometry. Precisely, the numerical stability and error analysis of this approximation scheme which is based on mixed finite-element method are performed. The particular application of a nickelcopper (NiCu) binary alloy, with real physical paramete...
Benchmarking nuclear models of FLUKA and GEANT4 for carbon ion therapy
Bohlen, TT; Quesada, J M; Bohlen, T T; Cerutti, F; Gudowska, I; Ferrari, A; Mairani, A
2010-01-01
As carbon ions, at therapeutic energies, penetrate tissue, they undergo inelastic nuclear reactions and give rise to significant yields of secondary fragment fluences. Therefore, an accurate prediction of these fluences resulting from the primary carbon interactions is necessary in the patient's body in order to precisely simulate the spatial dose distribution and the resulting biological effect. In this paper, the performance of nuclear fragmentation models of the Monte Carlo transport codes, FLUKA and GEANT4, in tissue-like media and for an energy regime relevant for therapeutic carbon ions is investigated. The ability of these Monte Carlo codes to reproduce experimental data of charge-changing cross sections and integral and differential yields of secondary charged fragments is evaluated. For the fragment yields, the main focus is on the consideration of experimental approximations and uncertainties such as the energy measurement by time-of-flight. For GEANT4, the hadronic models G4BinaryLightIonReaction a...
Stochastic model of energetic nuclear reactor
International Nuclear Information System (INIS)
Bojko, R.V.; Ryazanov, V.V.
2002-01-01
Behaviour of nuclear reactor was treated using the theory of branching processes. As mathematical model descriptive the neutron number in time the Markov occasional process is proposed. Application of branching occasional processes with variable regime to the description of neutron behaviour in the reactor makes possible conducting strong description of critical operation regime and demonstrates the severity of the process. Three regimes of the critical behaviour depending on the sign of manipulated variables and feedbacks were discovered. Probability regularities peculiar to the behaviour of the reactor are embodied to the suggested stochastic model [ru
A phenomenological model for nuclear multifragmentation
International Nuclear Information System (INIS)
Souza, S.R.; Leray, S.; Paula, L. de; Nemeth, J.; Ngo, C.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette; Ngo, H.
1992-01-01
A phenomenological model for nuclear multifragmentation is presented. It is made up of two complementary parts: molecular dynamics and restructured aggregation. It is applied to study the multifragmentation of 16 O+ 80 Br system at several bombarding energies. The results turn out to be in good agreement with available emulsion data. The production of charged particles and IMF as a function of the bombarding energy is also studied. The results seem to agree quite well with experimental observations and with previous results of other model calculations. (author) 19 refs.; 5 figs.; 1 tab
International Nuclear Information System (INIS)
Aboufirassi, M; Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Meslin, C.; Metivier, V.; Nakagawa, T.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Wieloch, A.; Yuasa-Nakagawa, K.
1998-01-01
The binary character of the heavy ion collisions at intermediate energies in the exit channel has been observed under 30 MeV/n in medium and heavy systems. Measurements in light systems at energies approaching ∼ 100 MeV/nucleon as well as in very heavy systems have allowed to extend considerably the investigations of this binary process. Thus, the study of the Pb + Au system showed that the complete charge events indicated two distinct sources: the quasi-projectile and the quasi-target. The characteristics of these two sources are rather well reproduced by a trajectory computation which takes into account the Coulomb and nuclear forces and the friction appearing from the projectile-target interaction. The Wilczynski diagram is used to probe the correlation between the kinetic energy quenching and the deflecting angle. In case of the system Pb + Au at 29 MeV/nucleon the diagram indicate dissipative binary collisions typical for low energies. This binary aspect was also detected in the systems Xe + Ag at 44 MeV/nucleon, 36 Ar + 27 Al and 64 Zn + nat Ti. Thus, it was possible to reconstruct the quasi-projectile and to study its mass and excitation energy evolution as a function of the impact parameter. The dissipative binary collisions represent for the systems and energies under considerations the main contribution to the cross section. This does not implies that there are not other processes; particularly, the more or less complete fusion is also observed but with a low cross section which decreases with the increase of bombardment energy. More exclusive measurements with the INDRA detector on quasi-symmetric systems as Ar + KCl and Xe + Sn seem to confirm the importance of the binary collisions. The two source reconstruction of the Xe + Sn data at 50 MeV/nucleon reproduces the same behaviour as that observed in the system Pb + Au at 29 MeV/nucleon
Few-body models for nuclear astrophysics
Energy Technology Data Exchange (ETDEWEB)
Descouvemont, P., E-mail: pdesc@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Baye, D., E-mail: dbaye@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Physique Quantique, C.P. 165/82, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Suzuki, Y., E-mail: suzuki@nt.sc.niigata-u.ac.jp [Department of Physics, Niigata University, Niigata 950-2181 (Japan); RIKEN Nishina Center, Wako 351-0198 (Japan); Aoyama, S., E-mail: aoyama@cc.niigata-u.ac.jp [Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Arai, K., E-mail: arai@nagaoka-ct.ac.jp [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata 940-8532 (Japan)
2014-04-15
We present applications of microscopic models to nuclear reactions of astrophysical interest, and we essentially focus on few-body systems. The calculation of radiative-capture and transfer cross sections is outlined, and we discuss the corresponding reaction rates. Microscopic theories are briefly presented, and we emphasize on the matrix elements of four-body systems. The microscopic extension of the R-matrix theory to nuclear reactions is described. Applications to the {sup 2}H(d, γ){sup 4}He, {sup 2}H(d, p){sup 3}H and {sup 2}H(d, n){sup 3}He reactions are presented. We show the importance of the tensor force to reproduce the low-energy behaviour of the cross sections.
Combinatorial nuclear level-density model
International Nuclear Information System (INIS)
Uhrenholt, H.; Åberg, S.; Dobrowolski, A.; Døssing, Th.; Ichikawa, T.; Möller, P.
2013-01-01
A microscopic nuclear level-density model is presented. The model is a completely combinatorial (micro-canonical) model based on the folded-Yukawa single-particle potential and includes explicit treatment of pairing, rotational and vibrational states. The microscopic character of all states enables extraction of level-distribution functions with respect to pairing gaps, parity and angular momentum. The results of the model are compared to available experimental data: level spacings at neutron separation energy, data on total level-density functions from the Oslo method, cumulative level densities from low-lying discrete states, and data on parity ratios. Spherical and deformed nuclei follow basically different coupling schemes, and we focus on deformed nuclei
International Nuclear Information System (INIS)
Bejarano, Arturo; Gutierrez, Jorge E.; Araus, Karina A.; Fuente, Juan C. de la
2011-01-01
Research highlights: → (Vapor + liquid) equilibria of three (CO 2 + C 5 alcohol) binary systems were measured. → Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. → No liquid immiscibility was observed at the temperatures and pressures studied. → Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. → Correlation results showed relative deviations ≤8 % (liquid) and ≤2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO 2 + 3-methyl-2-butanol), (CO 2 + 2-pentanol), and (CO 2 + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO 2 + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.
Tarafder, Sumit; Toukir Ahmed, Md; Iqbal, Sumaiya; Tamjidul Hoque, Md; Sohel Rahman, M
2018-03-14
Accessible surface area (ASA) of a protein residue is an effective feature for protein structure prediction, binding region identification, fold recognition problems etc. Improving the prediction of ASA by the application of effective feature variables is a challenging but explorable task to consider, specially in the field of machine learning. Among the existing predictors of ASA, REGAd 3 p is a highly accurate ASA predictor which is based on regularized exact regression with polynomial kernel of degree 3. In this work, we present a new predictor RBSURFpred, which extends REGAd 3 p on several dimensions by incorporating 58 physicochemical, evolutionary and structural properties into 9-tuple peptides via Chou's general PseAAC, which allowed us to obtain higher accuracies in predicting both real-valued and binary ASA. We have compared RBSURFpred for both real and binary space predictions with state-of-the-art predictors, such as REGAd 3 p and SPIDER2. We also have carried out a rigorous analysis of the performance of RBSURFpred in terms of different amino acids and their properties, and also with biologically relevant case-studies. The performance of RBSURFpred establishes itself as a useful tool for the community. Copyright © 2018 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Del Pozzo, Walter; Veitch, John; Vecchio, Alberto
2011-01-01
Second-generation interferometric gravitational-wave detectors, such as Advanced LIGO and Advanced Virgo, are expected to begin operation by 2015. Such instruments plan to reach sensitivities that will offer the unique possibility to test general relativity in the dynamical, strong-field regime and investigate departures from its predictions, in particular, using the signal from coalescing binary systems. We introduce a statistical framework based on Bayesian model selection in which the Bayes factor between two competing hypotheses measures which theory is favored by the data. Probability density functions of the model parameters are then used to quantify the inference on individual parameters. We also develop a method to combine the information coming from multiple independent observations of gravitational waves, and show how much stronger inference could be. As an introduction and illustration of this framework-and a practical numerical implementation through the Monte Carlo integration technique of nested sampling-we apply it to gravitational waves from the inspiral phase of coalescing binary systems as predicted by general relativity and a very simple alternative theory in which the graviton has a nonzero mass. This method can (and should) be extended to more realistic and physically motivated theories.
Strassmeier, K. G.; Hall, D. S.; Henry, G. W.
1994-01-01
We present a time-dependent spot modeling analysis of 15 consecutive years of V-band photometry of the long-period (P(sub orb) = 28.6 days) RS CVn binary HR 7275. This baseline in time is one of the longest, uninterrupted intervals a spotted star has been observed. The spot modeling analysis yields a total of 20 different spots throughout the time span of our observations. The distribution of the observed spot migration rates is consistent with solar-type differential rotation and suggests a lower limit of the differential-rotation coefficient of 0.022 +/-0.004. The observed, maximum lifetime of a single spot (or spot group) is 4.5 years, the minimum lifetime is approximately one year, but an average spot lives for 2.2 years. If we assume that the mechanical shear by differential rotation sets the upper limit to the spot lifetime, the observed maximum lifetime in turn sets an upper limit to the differential-rotation coefficient, namely 0.04 +/- 0.01. This would be differential rotation just 5 to 8 times less than the solar value and one of the strongest among active binaries. We found no conclusive evidence for the existence of a periodic phenomenon that could be attributed to a stellar magnetic cycle.
International Nuclear Model personal computer (PCINM): Model documentation
International Nuclear Information System (INIS)
1992-08-01
The International Nuclear Model (INM) was developed to assist the Energy Information Administration (EIA), U.S. Department of Energy (DOE) in producing worldwide projections of electricity generation, fuel cycle requirements, capacities, and spent fuel discharges from commercial nuclear reactors. The original INM was developed, maintained, and operated on a mainframe computer system. In spring 1992, a streamlined version of INM was created for use on a microcomputer utilizing CLIPPER and PCSAS software. This new version is known as PCINM. This documentation is based on the new PCINM version. This document is designed to satisfy the requirements of several categories of users of the PCINM system including technical analysts, theoretical modelers, and industry observers. This document assumes the reader is familiar with the nuclear fuel cycle and each of its components. This model documentation contains four chapters and seven appendices. Chapter Two presents the model overview containing the PCINM structure and process flow, the areas for which projections are made, and input data and output reports. Chapter Three presents the model technical specifications showing all model equations, algorithms, and units of measure. Chapter Four presents an overview of all parameters, variables, and assumptions used in PCINM. The appendices present the following detailed information: variable and parameter listings, variable and equation cross reference tables, source code listings, file layouts, sample report outputs, and model run procedures. 2 figs
Urban meteorological modelling for nuclear emergency preparedness
International Nuclear Information System (INIS)
Baklanov, Alexander; Sorensen, Jens Havskov; Hoe, Steen Cordt; Amstrup, Bjarne
2006-01-01
The main objectives of the current EU project 'Integrated Systems for Forecasting Urban Meteorology, Air Pollution and Population Exposure' (FUMAPEX) are the improvement of meteorological forecasts for urban areas, the connection of numerical weather prediction (NWP) models to urban air pollution and population dose models, the building of improved urban air quality information and forecasting systems, and their application in cities in various European climates. In addition to the forecast of the worst air-pollution episodes in large cities, the potential use of improved weather forecasts for nuclear emergency management in urban areas, in case of hazardous releases from nuclear accidents or terror acts, is considered. Such use of NWP data is tested for the Copenhagen metropolitan area and the Oresund region. The Danish Meteorological Institute (DMI) is running an experimental version of the HIRLAM NWP model over Zealand including the Copenhagen metropolitan area with a horizontal resolution of 1.4 km, thus approaching the city-scale. This involves 1-km resolution physiographic data with implications for the urban surface parameters, e.g. surface fluxes, roughness length and albedo. For the city of Copenhagen, the enhanced high-resolution NWP forecasting will be provided to demonstrate the improved dispersion forecasting capabilities of the Danish nuclear emergency preparedness decision-support system, the Accident Reporting and Guidance Operational System (ARGOS), used by the Danish Emergency Management Agency (DEMA). Recently, ARGOS has been extended with a capability of real-time calculation of regional-scale atmospheric dispersion of radioactive material from accidental releases. This is effectuated through on-line interfacing with the Danish Emergency Response Model of the Atmosphere (DERMA), which is run at DMI. For local-scale modelling of atmospheric dispersion, ARGOS utilises the Local-Scale Model Chain (LSMC), which makes use of high-resolution DMI
Loganathan, Paripurnanda; Shim, Wang Geun; Sounthararajah, Danious Pratheep; Kalaruban, Mahatheva; Nur, Tanjina; Vigneswaran, Saravanamuthu
2018-03-30
Elevated concentrations of heavy metals in water can be toxic to humans, animals, and aquatic organisms. A study was conducted on the removal of Cu, Pb, and Zn by a commonly used water treatment adsorbent, granular activated carbon (GAC), from three single, three binary (Cu-Pb, Cu-Zn, Pb-Zn), and one ternary (Cu-Pb-Zn) combination of metals. It also investigated seven mathematical models on their suitability to predict the metals adsorption capacities. Adsorption of Cu, Pb, and Zn increased with pH with an abrupt increase in adsorption at around pH 5.5, 4.5, and 6.0, respectively. At all pHs tested (2.5-7.0), the adsorption capacity followed the order Pb > Cu > Zn. The Langmuir and Sips models fitted better than the Freundlich model to the data in the single-metal system at pH 5. The Langmuir maximum adsorption capacities of Pb, Cu, and Zn (mmol/g) obtained from the model's fits were 0.142, 0.094, and 0.058, respectively. The adsorption capacities (mmol/g) for these metals at 0.01 mmol/L equilibrium liquid concentration were 0.130, 0.085, and 0.040, respectively. Ideal Adsorbed Solution (IAS)-Langmuir and IAS-Sips models fitted well to the binary and ternary metals adsorption data, whereas the Extended Langmuir and Extended Sips models' fits to the data were poor. The selectivity of adsorption followed the same order as the metals' capacities and affinities of adsorption in the single-metal systems.
International Nuclear Information System (INIS)
Kang, Young-Mook; Oh, Kyunghwan; You, Hwan; No, Kyoung Tai; Jeon, Yukwon; Shul, Yong-Gun; Hwang, Sung Bo; Shin, Hyun Kil; Kim, Min Sung; Kim, Namseok; Son, Hyoungjun; Chu, Young Hwan; Cho, Kwang-Hwi
2016-01-01
Ethylbenzene (EB) and p-xylene (PX) are important chemicals for the production of industrial materials; accordingly, their efficient separation is desired, even though the difference in their boiling points is very small. This paper describes the efforts toward the identification of high-performance extractive agents for EB and PX separation by distillation. Most high-performance extractive agents contain halogen atoms, which present health hazards and are corrosive to distillation plates. To avoid this disadvantage of extractive agents, we developed a quantitative structure-relative volatility relationship (QSRVR) model for designing safe extractive agents. We have previously developed and reported QSRVR models for single extractive agents. In this study, we introduce extended QSRVR models for binary and ternary extractive agents. The QSRVR models accurately predict the relative volatilities of binary and ternary extractive agents. The service to predict the relative volatility for binary and ternary extractive agents is freely available from the Internet at http://qsrvr.o pengsi.org/.
Energy Technology Data Exchange (ETDEWEB)
Kang, Young-Mook; Oh, Kyunghwan; You, Hwan; No, Kyoung Tai [Bioinformatics and Molecular Design Research Center, Seoul (Korea, Republic of); Jeon, Yukwon; Shul, Yong-Gun; Hwang, Sung Bo; Shin, Hyun Kil; Kim, Min Sung; Kim, Namseok; Son, Hyoungjun [Yonsei University, Seoul (Korea, Republic of); Chu, Young Hwan [Sangji University, Wonju (Korea, Republic of); Cho, Kwang-Hwi [Soongsil University, Seoul (Korea, Republic of)
2016-04-15
Ethylbenzene (EB) and p-xylene (PX) are important chemicals for the production of industrial materials; accordingly, their efficient separation is desired, even though the difference in their boiling points is very small. This paper describes the efforts toward the identification of high-performance extractive agents for EB and PX separation by distillation. Most high-performance extractive agents contain halogen atoms, which present health hazards and are corrosive to distillation plates. To avoid this disadvantage of extractive agents, we developed a quantitative structure-relative volatility relationship (QSRVR) model for designing safe extractive agents. We have previously developed and reported QSRVR models for single extractive agents. In this study, we introduce extended QSRVR models for binary and ternary extractive agents. The QSRVR models accurately predict the relative volatilities of binary and ternary extractive agents. The service to predict the relative volatility for binary and ternary extractive agents is freely available from the Internet at http://qsrvr.o pengsi.org/.
Modeling closed nuclear fuel cycles processes
Energy Technology Data Exchange (ETDEWEB)
Shmidt, O.V. [A.A. Bochvar All-Russian Scientific Research Institute for Inorganic Materials, Rogova, 5a street, Moscow, 123098 (Russian Federation); Makeeva, I.R. [Zababakhin All-Russian Scientific Research Institute of Technical Physics, Vasiliev street 13, Snezhinsk, Chelyabinsk region, 456770 (Russian Federation); Liventsov, S.N. [Tomsk Polytechnic University, Tomsk, Lenin Avenue, 30, 634050 (Russian Federation)
2016-07-01
Computer models of processes are necessary for determination of optimal operating conditions for closed nuclear fuel cycle (NFC) processes. Computer models can be quickly changed in accordance with new and fresh data from experimental research. 3 kinds of process simulation are necessary. First, the VIZART software package is a balance model development used for calculating the material flow in technological processes. VIZART involves taking into account of equipment capacity, transport lines and storage volumes. Secondly, it is necessary to simulate the physico-chemical processes that are involved in the closure of NFC. The third kind of simulation is the development of software that allows the optimization, diagnostics and control of the processes which implies real-time simulation of product flows on the whole plant or on separate lines of the plant. (A.C.)
System model development for nuclear thermal propulsion
International Nuclear Information System (INIS)
Walton, J.T.; Perkins, K.R.; Buksa, J.J.; Worley, B.A.; Dobranich, D.
1992-01-01
A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented
Nuclear physics for applications. A model approach
International Nuclear Information System (INIS)
Prussin, S.G.
2007-01-01
Written by a researcher and teacher with experience at top institutes in the US and Europe, this textbook provides advanced undergraduates minoring in physics with working knowledge of the principles of nuclear physics. Simplifying models and approaches reveal the essence of the principles involved, with the mathematical and quantum mechanical background integrated in the text where it is needed and not relegated to the appendices. The practicality of the book is enhanced by numerous end-of-chapter problems and solutions available on the Wiley homepage. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Shi, Chang-Sheng; Zhang, Shuang-Nan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Li, Xiang-Dong, E-mail: zhangsn@ihep.ac.cn [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093 (China)
2015-11-10
We re-estimate the surface magnetic fields of neutron stars (NSs) in Be X-ray binaries (BeXBs) with different models of torque, improved beyond Klus et al. In particular, a new torque model is applied to three models of magnetosphere radius. Unlike the previous models, the new torque model does not lead to divergent results for any fastness parameter. The inferred surface magnetic fields of these NSs for the two compressed magnetosphere models are much higher than that for the uncompressed magnetosphere model. The new torque model using the compressed magnetosphere radius leads to unique solutions near spin equilibrium in all cases, unlike other models that usually give two branches of solutions. Although our conclusions are still affected by the simplistic assumptions about the magnetosphere radius calculations, we show several groups of possible surface magnetic field values with our new models when the interaction between the magnetosphere and the infalling accretion plasma is considered. The estimated surface magnetic fields for NSs BeXBs in the Large Magellanic Cloud, the Small Magellanic Cloud and the Milk Way are between the quantum critical field and the maximum “virial” value by the spin equilibrium condition.
Nuclear reactor core modelling in multifunctional simulators
International Nuclear Information System (INIS)
Puska, E.K.
1999-01-01
The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been
Nuclear reactor core modelling in multifunctional simulators
Energy Technology Data Exchange (ETDEWEB)
Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)
1999-06-01
The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been
Chen, Wansu; Shi, Jiaxiao; Qian, Lei; Azen, Stanley P
2014-06-26
To estimate relative risks or risk ratios for common binary outcomes, the most popular model-based methods are the robust (also known as modified) Poisson and the log-binomial regression. Of the two methods, it is believed that the log-binomial regression yields more efficient estimators because it is maximum likelihood based, while the robust Poisson model may be less affected by outliers. Evidence to support the robustness of robust Poisson models in comparison with log-binomial models is very limited. In this study a simulation was conducted to evaluate the performance of the two methods in several scenarios where outliers existed. The findings indicate that for data coming from a population where the relationship between the outcome and the covariate was in a simple form (e.g. log-linear), the two models yielded comparable biases and mean square errors. However, if the true relationship contained a higher order term, the robust Poisson models consistently outperformed the log-binomial models even when the level of contamination is low. The robust Poisson models are more robust (or less sensitive) to outliers compared to the log-binomial models when estimating relative risks or risk ratios for common binary outcomes. Users should be aware of the limitations when choosing appropriate models to estimate relative risks or risk ratios.
Analytical model of radiation-induced precipitation at the surface of dilute binary alloy
Pechenkin, V. A.; Stepanov, I. A.; Konobeev, Yu. V.
2002-12-01
Growth of precipitate layer at the foil surface of an undersaturated binary alloy under uniform irradiation is treated analytically. Analytical expressions for the layer growth rate, layer thickness limit and final component concentrations in the matrix are derived for coherent and incoherent precipitate-matrix interfaces. It is shown that the high temperature limit of radiation-induced precipitation is the same for both types of interfaces, whereas layer thickness limits are different. A parabolic law of the layer growth predicted for both types of interfaces is in agreement with experimental data on γ '-phase precipitation at the surface of Ni-Si dilute alloys under ion irradiation. Effect of sputtering on the precipitation rate and on the low temperature limit of precipitation under ion irradiation is discussed.
International Nuclear Information System (INIS)
Gutierrez, Jorge E.; Bejarano, Arturo; Fuente, Juan C. de la
2010-01-01
An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at 2 + 1-propanol), (CO 2 + 2-methyl-1-propanol), (CO 2 + 3-methyl-1-butanol), and (CO 2 + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO 2 + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively.
Bright, Jane; Torres, Guillermo
2018-01-01
We report new spectroscopic observations of the F-type triple system V2154 Cyg, in which two of the stars form an eclipsing binary with a period of 2.6306303 ± 0.0000038 days. We combine the results from our spectroscopic analysis with published light curves in the uvby Strömgren passbands to derive the first reported absolute dimensions of the stars in the eclipsing binary. The masses and radii are measured with high accuracy to better than 1.5% precision. For the primary and secondary respectively, we find that the masses are 1.269 ± 0.017 M⊙ and 0.7542 ± 0.0059 M⊙, the radii are 1.477 ± 0.012 R⊙ and 0.7232 ± 0.0091R⊙, and the temperatures are 6770 ± 150 K and 5020 ± 150 K. Current models of stellar evolution agree with the measured properties of the primary, but the secondary is larger than predicted. This may be due to activity in the secondary, as has been shown for other systems with a star of similar mass with this same discrepancy.The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution. GT acknowledges partial support for this work from NSF grant AST-1509375.
Pizzirusso, Antonio; Brasiello, Antonio; De Nicola, Antonio; Marangoni, Alejandro G.; Milano, Giuseppe
2015-12-01
The first simulation study of the crystallisation of a binary mixture of triglycerides using molecular dynamics simulations is reported. Coarse-grained models of tristearin (SSS) and tripalmitin (PPP) molecules have been considered. The models have been preliminarily tested in the crystallisation of pure SSS and PPP systems. Two different quenching procedures have been tested and their performances have been analysed. The structures obtained from the crystallisation procedures show a high orientation order and a high content of molecules in the tuning fork conformation, comparable with the crystalline α phase. The behaviour of melting temperatures for the α phase of the mixture SSS/PPP obtained from the simulations is in qualitative agreement with the behaviour that was experimentally determined.
International Nuclear Information System (INIS)
Pizzirusso, Antonio; De Nicola, Antonio; Milano, Giuseppe; Brasiello, Antonio; Marangoni, Alejandro G
2015-01-01
The first simulation study of the crystallisation of a binary mixture of triglycerides using molecular dynamics simulations is reported. Coarse-grained models of tristearin (SSS) and tripalmitin (PPP) molecules have been considered. The models have been preliminarily tested in the crystallisation of pure SSS and PPP systems. Two different quenching procedures have been tested and their performances have been analysed. The structures obtained from the crystallisation procedures show a high orientation order and a high content of molecules in the tuning fork conformation, comparable with the crystalline α phase. The behaviour of melting temperatures for the α phase of the mixture SSS/PPP obtained from the simulations is in qualitative agreement with the behaviour that was experimentally determined. (paper)
Energy Technology Data Exchange (ETDEWEB)
Chang, H.; Yuan, X.G.; Tian, H.; Zeng, A.W. [State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072 (China)
2006-04-15
The adsorption capacity of water and ethanol on cornmeal in an ethanol-water binary vapor system was investigated in a fixed-bed apparatus for ethanol dehydration. Experiments were performed at temperatures of 82-100 C for different relative humidities of ethanol-water vapor. Adsorption equilibrium models, including those based on the adsorption potential theory of Polanyi and Sircar's model, have been used to fit the experimental data for water adsorption on cornmeal, and all gave good fits. For ethanol adsorption, pseudo-equilibrium was defined as the mass adsorbed on the cornmeal within the time needed for the equilibrium for water on the same adsorbent. Based on this limiting condition, adsorption behaviors and mechanisms were analyzed. (Abstract Copyright [2006], Wiley Periodicals, Inc.)
DEFF Research Database (Denmark)
Keiding, Hans; Peleg, Bezalel
2006-01-01
is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...
International Nuclear Information System (INIS)
Schroeder, Joshua; Halpern, Jules
2014-01-01
We present observations of fields containing eight recently discovered binary millisecond pulsars using the telescopes at MDM Observatory. Optical counterparts to four of these systems are detected, one of which, PSR J2214+3000, is a novel detection. Additionally, we present the fully phase-resolved B, V, and R light curves of the optical counterparts to two objects, PSR J1810+1744 and PSR J2215+5135 for which we employ model fitting using the eclipsing light curve (ELC) model of Orosz and Hauschildt to measure the unknown system parameters. For PSR J1810+1744, we find that the system parameters cannot be fit even assuming that 100% of the spin-down luminosity of the pulsar is irradiating the secondary, and so radial velocity measurements of this object will be required for the complete solution. However, PSR J2215+5135 exhibits light curves that are extremely well constrained using the ELC model and we find that the mass of the neutron star is constrained by these and the radio observations to be M NS > 1.75 M ☉ at the 3σ level. We also find a discrepancy between the model temperature and the measured colors of this object, which we interpret as possible evidence for an additional high-temperature source such as a quiescent disk. Given this and the fact that PSR J2215+5135 contains a relatively high mass companion (M c > 0.1 M ☉ ), we propose that similar to the binary pulsar systems PSR J1023+0038 and IGR J18245–2452, the pulsar may transition between accretion- and rotation-powered modes.
Nuclear power investment risk economic model
International Nuclear Information System (INIS)
Houghton, W.J.; Postula, F.D.
1985-12-01
This paper describes an economic model which was developed to evaluate the net costs incurred by a utility due to an accident induced outage at a nuclear power plant. During such an outage the portion of the plant operating costs associated with power production are saved; however, the owning utility faces a sizable expense as fossil fuels are burned as a substitute for the incapacitated nuclear power. Additional expenses are incurred by the utility for plant repair and if necessary, decontamination costs. The model makes provision for mitigating these costs by sales of power, property damage insurance payments, tax write-offs and increased rates. Over 60 economic variables contribute to the net cost uncertainty. The values of these variables are treated as uncertainty distributions and are used in a Monte carlo computer program to evaluate the cost uncertainty (investment risk) associated with damage which could occur from various categories of initiating accidents. As an example, results of computations for various levels of damage associated with a loss of coolant accident are shown as a range of consequential plant downtime and unrecovered cost. A typical investment risk profile is shown for these types of accidents. Cost/revenue values for each economic factor are presented for a Three Mile Island - II type accident, e.g., uncontrolled core heatup. 4 refs., 6 figs., 3 tabs
The imagine of establishing China nuclear insurance model
International Nuclear Information System (INIS)
Wu Yimin
2010-01-01
Nuclear power Insurance is one important technique for risk managements of Nuclear power Enterprises. At present, nuclear risk of Nuclear power plants in China has been mainly supported by China Nuclear Insurance pool (hereinafter called CNP) to get coverage from International Nuclear Insurance pool (hereinafter called NIP). CNIP has several advantages to confirm low-cost. Operation, such as large underwriting capacity, international approval and cession, direct writing without agents. However, there are both deficiencies, first, can not get rid of dependence on International markets ; second, in the absence of competition in Self- insurance organizations , tough and opaque premium offer greatly restricted the enthusiasm for Nuclear power plants insuring .But the next ten year is a golden decade for China Nuclear industry development; Nuclear power market is demonstrating tremendous growth potential. With new units put into operation, all kinds of nuclear insurance demand will release when subject-matter insured substantially increase. So, breaking the current bottleneck of China Nuclear Insurance and establishing China Nuclear Insurance (hereinafter called: Nuclear insurance) model adapting to China national conditions will play an important role in Nuclear power development. I made the advice that both domestic nuclear enterprises and general insurance companies initiate a 'Nuclear insurance company'. (authors)
International Nuclear Information System (INIS)
Debón, A.; Carlos Garcia-Díaz, J.
2012-01-01
Advanced statistical models can help industry to design more economical and rational investment plans. Fault detection and diagnosis is an important problem in continuous hot dip galvanizing. Increasingly stringent quality requirements in the automotive industry also require ongoing efforts in process control to make processes more robust. Robust methods for estimating the quality of galvanized steel coils are an important tool for the comprehensive monitoring of the performance of the manufacturing process. This study applies different statistical regression models: generalized linear models, generalized additive models and classification trees to estimate the quality of galvanized steel coils on the basis of short time histories. The data, consisting of 48 galvanized steel coils, was divided into sets of conforming and nonconforming coils. Five variables were selected for monitoring the process: steel strip velocity and four bath temperatures. The present paper reports a comparative evaluation of statistical models for binary data using Receiver Operating Characteristic (ROC) curves. A ROC curve is a graph or a technique for visualizing, organizing and selecting classifiers based on their performance. The purpose of this paper is to examine their use in research to obtain the best model to predict defective steel coil probability. In relation to the work of other authors who only propose goodness of fit statistics, we should highlight one distinctive feature of the methodology presented here, which is the possibility of comparing the different models with ROC graphs which are based on model classification performance. Finally, the results are validated by bootstrap procedures.
DEFF Research Database (Denmark)
Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens
2013-01-01
The complex fluid phase behaviour, of the binary system comprised of water and tetrahydrofuran (THF) is modelled by use of the cubic-plus-association (CPA) equation of state. A total of seven modelling approaches are analysed, differing only in their way of describing THF and its interactions...
International Nuclear Information System (INIS)
Hillwig, Todd C.; Bond, Howard E.; Afsar, Melike; De Marco, Orsola
2010-01-01
Close-binary central stars of planetary nebulae (CSPNe) provide an opportunity to explore the evolution of PNe, their shaping, and the evolution of binary systems undergoing a common-envelope phase. Here, we present the results of time-resolved photometry of the binary central stars (CSs) of the PNe NGC 6026 and NGC 6337 as well as time-resolved spectroscopy of the CS of NGC 6026. The results of a period analysis give an orbital period of 0.528086(4) days for NGC 6026 and a photometric period of 0.1734742(5) days for NGC 6337. In the case of NGC 6337, it appears that the photometric period reflects the orbital period and that the variability is the result of the irradiated hemisphere of a cool companion. The inclination of the thin PN ring is nearly face-on. Our modeled inclination range for the close central binary includes nearly face-on alignments and provides evidence for a direct binary-nebular shaping connection. For NGC 6026, however, the radial-velocity curve shows that the orbital period is twice the photometric period. In this case, the photometric variability is due to an ellipsoidal effect in which the CS nearly fills its Roche lobe and the companion is most likely a hot white dwarf. NGC 6026 then is the third PN with a confirmed central binary where the companion is compact. Based on the data and modeling using a Wilson-Devinney code, we discuss the physical parameters of the two systems and how they relate to the known sample of close-binary CSs, which comprise 15%-20% of all PNe.
International Nuclear Information System (INIS)
Zheng Yi
2008-01-01
A simple dynamic rising nuclear cloud based model for atmospheric nuclear explosion radioactive prediction was presented. The deposition of particles and initial cloud radius changing with time before the cloud stabilization was considered. Large-scale relative diffusion theory was used after cloud stabilization. The model was considered reasonable and dependable in comparison with four U.S. nuclear test cases and DELFIC model results. (authors)
Complex models of nodal nuclear data
International Nuclear Information System (INIS)
Dufek, Jan
2011-01-01
During the core simulations, nuclear data are required at various nodal thermal-hydraulic and fuel burnup conditions. The nodal data are also partially affected by thermal-hydraulic and fuel burnup conditions in surrounding nodes as these change the neutron energy spectrum in the node. Therefore, the nodal data are functions of many parameters (state variables), and the more state variables are considered by the nodal data models the more accurate and flexible the models get. The existing table and polynomial regression models, however, cannot reflect the data dependences on many state variables. As for the table models, the number of mesh points (and necessary lattice calculations) grows exponentially with the number of variables. As for the polynomial regression models, the number of possible multivariate polynomials exceeds the limits of existing selection algorithms that should identify a few dozens of the most important polynomials. Also, the standard scheme of lattice calculations is not convenient for modelling the data dependences on various burnup conditions since it performs only a single or few burnup calculations at fixed nominal conditions. We suggest a new efficient algorithm for selecting the most important multivariate polynomials for the polynomial regression models so that dependences on many state variables can be considered. We also present a new scheme for lattice calculations where a large number of burnup histories are accomplished at varied nodal conditions. The number of lattice calculations being performed and the number of polynomials being analysed are controlled and minimised while building the nodal data models of a required accuracy. (author)
DEFF Research Database (Denmark)
Fraser, Diane P.; Zuckermann, Martin J.; Mouritsen, Ole G.
1991-01-01
A two-dimensional Monte Carlo simulation method based on the NpT ensemble and the Voronoi tesselation, which was previously developed for single-species hard-disk systems, is extended, along with a version of scaled-particle theory, to many-component mixtures. These systems are unusual in the sense...... and internal degrees of freedom leads to a rich phase structure that includes solid-liquid transitions (governed by the translational variables) as well as transitions involving changes in average disk size (governed by the internal variables). The relationship between these two types of transitions is studied...... by the method in the case of a binary mixture, and results are presented for varying disk-size ratios and degeneracies. The results are also compared with the predictions of the extended scaled-particle theory. Applications of the model are discussed in relation to lipid monolayers spread on air...
Analytical model of the binary multileaf collimator of tomotherapy for Monte Carlo simulations
International Nuclear Information System (INIS)
Sterpin, E; Vynckier, S; Salvat, F; Olivera, G H
2008-01-01
Helical Tomotherapy (HT) delivers intensity-modulated radiotherapy by the means of many configurations of the binary multi-leaf collimator (MLC). The aim of the present study was to devise a method, which we call the 'transfer function' (TF) method, to perform the transport of particles through the MLC much faster than the time consuming Monte Carlo (MC) simulation and with no significant loss of accuracy. The TF method consists of calculating, for each photon in the phase-space file, the attenuation factor for each leaf (up to three) that the photon passes, assuming straight propagation through closed leaves, and storing these factors in a modified phase-space file. To account for the transport through the MLC in a given configuration, the weight of a photon is simply multiplied by the attenuation factors of the leaves that are intersected by the photon ray and are closed. The TF method was combined with the PENELOPE MC code, and validated with measurements for the three static field sizes available (40x5, 40x2.5 and 40x1 cm 2 ) and for some MLC patterns. The TF method allows a large reduction in computation time, without introducing appreciable deviations from the result of full MC simulations
Persistent junk solutions in time-domain modeling of extreme mass ratio binaries
International Nuclear Information System (INIS)
Field, Scott E.; Hesthaven, Jan S.; Lau, Stephen R.
2010-01-01
In the context of metric perturbation theory for nonspinning black holes, extreme mass ratio binary systems are described by distributionally forced master wave equations. Numerical solution of a master wave equation as an initial boundary value problem requires initial data. However, because the correct initial data for generic-orbit systems is unknown, specification of trivial initial data is a common choice, despite being inconsistent and resulting in a solution which is initially discontinuous in time. As is well known, this choice leads to a burst of junk radiation which eventually propagates off the computational domain. We observe another potential consequence of trivial initial data: development of a persistent spurious solution, here referred to as the Jost junk solution, which contaminates the physical solution for long times. This work studies the influence of both types of junk on metric perturbations, waveforms, and self-force measurements, and it demonstrates that smooth modified source terms mollify the Jost solution and reduce junk radiation. Our concluding section discusses the applicability of these observations to other numerical schemes and techniques used to solve distributionally forced master wave equations.
Algebraic fermion models and nuclear structure physics
International Nuclear Information System (INIS)
Troltenier, Dirk; Blokhin, Andrey; Draayer, Jerry P.; Rompf, Dirk; Hirsch, Jorge G.
1996-01-01
Recent experimental and theoretical developments are generating renewed interest in the nuclear SU(3) shell model, and this extends to the symplectic model, with its Sp(6,R) symmetry, which is a natural multi-(ℎ/2π)ω extension of the SU(3) theory. First and foremost, an understanding of how the dynamics of a quantum rotor is embedded in the shell model has established it as the model of choice for describing strongly deformed systems. Second, the symplectic model extension of the 0-(ℎ/2π)ω theory can be used to probe additional degrees of freedom, like core polarization and vorticity modes that play a key role in providing a full description of quadrupole collectivity. Third, the discovery and understanding of pseudo-spin has allowed for an extension of the theory from light (A≤40) to heavy (A≥100) nuclei. Fourth, a user-friendly computer code for calculating reduced matrix elements of operators that couple SU(3) representations is now available. And finally, since the theory is designed to cope with deformation in a natural way, microscopic features of deformed systems can be probed; for example, the theory is now being employed to study double beta decay and thereby serves to probe the validity of the standard model of particles and their interactions. A subset of these topics will be considered in this course--examples cited include: a consideration of the origin of pseudo-spin symmetry; a SU(3)-based interpretation of the coupled-rotor model, early results of double beta decay studies; and some recent developments on the pseudo-SU(3) theory. Nothing will be said about other fermion-based theories; students are referred to reviews in the literature for reports on developments in these related areas
Lizotte, Todd E.; Ohar, Orest P.; Tuttle, Tracie
2006-04-01
Performance of diffractive optics is determined by high-quality design and a suitable fabrication process that can actually realize the design. Engineers who are tasked with developing or implementing a diffractive optic solution into a product need to take into consideration the risks of using grayscale versus binary fabrication processes. In many cases, grayscale design doesn't always provide the best solution or cost benefit during product development. This fabrication dilemma arises when the engineer has to select a source for design and/or fabrication. Engineers come face to face with reality in view of the fact that diffractive optic suppliers tend to provide their services on a "best effort basis". This can be very disheartening to an engineer who is trying to implement diffractive optics. This paper will compare and contrast the design and performance of a 1 to 24 beam, two dimensional; beam splitter fabricated using a fifty (50) phase level grayscale and a five (5) phase level binary fabrication methods. Optical modeling data will be presented showing both designs and the performance expected prior to fabrication. An overview of the optical testing methods used will be discussed including the specific test equipment and metrology techniques used to verify actual optical performance and fabricated dimensional stability of each optical element. Presentation of the two versions of the splitter will include data on fabrication dimensional errors, split beam-to-beam uniformity, split beam-to-beam spatial size uniformity and splitter efficiency as compared to the original intended design performance and models. This is a continuation of work from 2005, Laser Beam Shaping VI.
Astronomy of binary and multiple stars
International Nuclear Information System (INIS)
Tokovinin, A.A.
1984-01-01
Various types of binary stars and methods for their observation are described in a popular form. Some models of formation and evolution of binary and multiple star systems are presented. It is concluded that formation of binary and multiple stars is a regular stage in the process of star production
Comparison of models of high energy nuclear collisions
International Nuclear Information System (INIS)
Gyulassy, M.
1978-01-01
The treatment of high energy nuclear reaction models covers goals of such collisions, the choice of theoretical framework, the zoo of models (p inclusive), light composites, models versus experiment, conclusions drawn, needed experiments, and pion production. 30 diagrams
Microstructural modelling of nuclear graphite using multi-phase models
International Nuclear Information System (INIS)
Berre, C.; Fok, S.L.; Marsden, B.J.; Mummery, P.M.; Marrow, T.J.; Neighbour, G.B.
2008-01-01
This paper presents a new modelling technique using three-dimensional multi-phase finite element models in which meshes representing the microstructure of thermally oxidised nuclear graphite were generated from X-ray micro-tomography images. The density of the material was related to the image greyscale using Beer-Lambert's law, and multiple phases could thus be defined. The local elastic and non-linear properties of each phase were defined as a function of density and changes in Young's modulus, tensile and compressive strength with thermal oxidation were calculated. Numerical predictions compared well with experimental data and with other numerical results obtained using two-phase models. These models were found to be more representative of the actual microstructure of the scanned material than two-phase models and, possibly because of pore closure occurring during compression, compressive tests were also predicted to be less sensitive to the microstructure geometry than tensile tests
Danandeh Mehr, Ali; Nourani, Vahid; Hrnjica, Bahrudin; Molajou, Amir
2017-12-01
The effectiveness of genetic programming (GP) for solving regression problems in hydrology has been recognized in recent studies. However, its capability to solve classification problems has not been sufficiently explored so far. This study develops and applies a novel classification-forecasting model, namely Binary GP (BGP), for teleconnection studies between sea surface temperature (SST) variations and maximum monthly rainfall (MMR) events. The BGP integrates certain types of data pre-processing and post-processing methods with conventional GP engine to enhance its ability to solve both regression and classification problems simultaneously. The model was trained and tested using SST series of Black Sea, Mediterranean Sea, and Red Sea as potential predictors as well as classified MMR events at two locations in Iran as predictand. Skill of the model was measured in regard to different rainfall thresholds and SST lags and compared to that of the hybrid decision tree-association rule (DTAR) model available in the literature. The results indicated that the proposed model can identify potential teleconnection signals of surrounding seas beneficial to long-term forecasting of the occurrence of the classified MMR events.
Energy Technology Data Exchange (ETDEWEB)
Roux, P
2005-12-15
This work deals with the modelling of dendritic solidification in binary mixtures. Large scale phenomena are represented by volume averaging of the local conservation equations. This method allows to rigorously derive the partial differential equations of averaged fields and the closure problems associated to the deviations. Such problems can be resolved numerically on periodic cells, representative of dendritic structures, in order to give a precise evaluation of macroscopic transfer coefficients (Drag coefficients, exchange coefficients, diffusion-dispersion tensors...). The method had already been applied for a model of columnar dendritic mushy zone and it is extended to the case of equiaxed dendritic solidification, where solid grains can move. The two-phase flow is modelled with an Eulerian-Eulerian approach and the novelty is to account for the dispersion of solid velocity through the kinetic agitation of the particles. A coupling of the two models is proposed thanks to an original adaptation of the columnar model, allowing for undercooling calculation: a solid-liquid interfacial area density is introduced and calculated. At last, direct numerical simulations of crystal growth are proposed with a diffuse interface method for a representation of local phenomena. (author)
Theoretical modelling of nuclear waste flows - 16377
International Nuclear Information System (INIS)
Adams, J.F.; Biggs, S.R.; Fairweather, M.; Njobuenwu, D.; Yao, J.
2009-01-01
A large amount of nuclear waste is stored in tailings ponds as a solid-liquid slurry, and liquid flows containing suspensions of solid particles are encountered in the treatment and disposal of this waste. In processing this waste, it is important to understand the behaviour of particles within the flow in terms of their settling characteristics, their propensity to form solid beds, and the re-suspension characteristics of particles from a bed. A clearer understanding of such behaviour would allow the refinement of current approaches to waste management, potentially leading to reduced uncertainties in radiological impact assessments, smaller waste volumes and lower costs, accelerated clean-up, reduced worker doses, enhanced public confidence and diminished grounds for objection to waste disposal. Mathematical models are of significant value in nuclear waste processing since the extent of characterisation of wastes is in general low. Additionally, waste processing involves a diverse range of flows, within vessels, ponds and pipes. To investigate experimentally all waste form characteristics and potential flows of interest would be prohibitively expensive, whereas the use of mathematical models can help to focus experimental studies through the more efficient use of existing data, the identification of data requirements, and a reduction in the need for process optimisation in full-scale experimental trials. Validated models can also be used to predict waste transport behaviour to enable cost effective process design and continued operation, to provide input to process selection, and to allow the prediction of operational boundaries that account for the different types and compositions of particulate wastes. In this paper two mathematical modelling techniques, namely Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES), have been used to investigate particle-laden flows in a straight square duct and a duct with a bend. The flow solutions provided by
Modeling a nuclear reactor for experimental purposes
International Nuclear Information System (INIS)
Berta, V.T.
1980-01-01
The Loss-of-Fluid Test (LOFT) Facility is a scale model of a commercial PWR and is as fully functional and operational as the generic commercial counterpart. LOFT was designed and built for experimental purposes as part of the overall NRC reactor safety research program. The purpose of LOFT is to assess the capability of reactor safety systems to perform their intended functions during occurrences of off-normal conditions in a commercial nuclear reactor. Off-normal conditions arising from large and small break loss-of-coolant accidents (LOCA), operational transients, and anticipated transients without scram (ATWS) were to be investigated. This paper describes the LOFT model of the generic PWR and summarizes the experiments that have been conducted in the context of the significant findings involving the complex transient thermal-hydraulics and the consequent effects on the commercial reactor analytical licensing techniques. Through these techniques the validity of the LOFT model as a scaled counterpart of the generic PWR is shown
Relativistic Binaries in Globular Clusters
Directory of Open Access Journals (Sweden)
Matthew J. Benacquista
2013-03-01
Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Lamorgese, A.; Mauri, R.
2017-04-01
We simulate the mixing (demixing) process of a quiescent binary liquid mixture with a composition-dependent viscosity which is instantaneously brought from the two-phase (one-phase) to the one-phase (two-phase) region of its phase diagram. Our theoretical approach follows a standard diffuse-interface model of partially miscible regular binary mixtures wherein convection and diffusion are coupled via a nonequilibrium capillary force, expressing the tendency of the phase-separating system to minimize its free energy. Based on 2D simulation results, we discuss the influence of viscosity ratio on basic statistics of the mixing (segregation) process triggered by a rapid heating (quench), assuming that the ratio of capillary to viscous forces (a.k.a. the fluidity coefficient) is large. We show that, for a phase-separating system, at a fixed value of the fluidity coefficient (with the continuous phase viscosity taken as a reference), the separation depth and the characteristic length of single-phase microdomains decrease monotonically for increasing values of the viscosity of the dispersed phase. This variation, however, is quite small, in agreement with experimental results. On the other hand, as one might expect, at a fixed viscosity of the dispersed phase both of the above statistics increase monotonically as the viscosity of the continuous phase decreases. Finally, we show that for a mixing system the attainment of a single-phase equilibrium state by coalescence and diffusion is retarded by an increase in the viscosity ratio at a fixed fluidity for the dispersed phase. In fact, for large enough values of the viscosity ratio, a thin film of the continuous phase becomes apparent when two drops of the minority phase approach each other, which further retards coalescence.
Charlier, G.W.P.
1994-01-01
In a binary choice panel data model with individual effects and two time periods, Manski proposed the maximum score estimator, based on a discontinuous objective function, and proved its consistency under weak distributional assumptions. However, the rate of convergence of this estimator is low (N)
International Nuclear Information System (INIS)
Pereira, Luís M.C.; Chapoy, Antonin; Burgass, Rod; Tohidi, Bahman
2016-01-01
Highlights: • (Density + IFT) measurements are performed in synthetic reservoir fluids. • Measured systems include CO_2, CH_4 and N_2 with n-decane. • Novel data are reported for temperatures up to 443 K and pressures up to 69 MPa. • Predictive models are tested in 16 (gas + n-alkane) systems. • Best modelling results are achieved with the Density Gradient Theory. - Abstract: The deployment of more efficient and economical extraction methods and processing facilities of oil and gas requires the accurate knowledge of the interfacial tension (IFT) of fluid phases in contact. In this work, the capillary constant a of binary mixtures containing n-decane and common gases such as carbon dioxide, methane and nitrogen was measured. Experimental measurements were carried at four temperatures (313, 343, 393 and 442 K) and pressures up to 69 MPa, or near the complete vaporisation of the organic phase into the gas-rich phase. To determine accurate IFT values, the capillary constants were combined with saturated phase density data measured with an Anton Paar densitometer and correlated with a model based on the Peng–Robinson 1978 equation of state (PR78 EoS). Correlated density showed an overall percentage absolute deviation (%AAD) to measured data of (0.2 to 0.5)% for the liquid phase and (1.5 to 2.5)% for the vapour phase of the studied systems and P–T conditions. The predictive capability of models to accurately describe both the temperature and pressure dependence of the saturated phase density and IFT of 16 (gas + n-alkane) binary mixtures was assessed in this work by comparison with data gathered from the literature and measured in this work. The IFT models considered include the Parachor, the Linear Gradient Theory (LGT) and the Density Gradient Theory (DGT) approaches combined with the Volume-Translated Predictive Peng–Robinson 1978 EoS (VT-PPR78 EoS). With no adjustable parameters, the VT-PPR78 EoS allowed a good description of both solubility and
Energy Technology Data Exchange (ETDEWEB)
Timchalk, Chuck; Poet, Torka S.
2008-05-01
Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models have been developed and validated for the organophosphorus (OP) insecticides chlorpyrifos (CPF) and diazinon (DZN). Based on similar pharmacokinetic and mode of action properties it is anticipated that these OPs could interact at a number of important metabolic steps including: CYP450 mediated activation/detoxification, and blood/tissue cholinesterase (ChE) binding/inhibition. We developed a binary PBPK/PD model for CPF, DZN and their metabolites based on previously published models for the individual insecticides. The metabolic interactions (CYP450) between CPF and DZN were evaluated in vitro and suggests that CPF is more substantially metabolized to its oxon metabolite than is DZN. These data are consistent with their observed in vivo relative potency (CPF>DZN). Each insecticide inhibited the other’s in vitro metabolism in a concentration-dependent manner. The PBPK model code used to described the metabolism of CPF and DZN was modified to reflect the type of inhibition kinetics (i.e. competitive vs. non-competitive). The binary model was then evaluated against previously published rodent dosimetry and ChE inhibition data for the mixture. The PBPK/PD model simulations of the acute oral exposure to single- (15 mg/kg) vs. binary-mixtures (15+15 mg/kg) of CFP and DZN at this lower dose resulted in no differences in the predicted pharmacokinetics of either the parent OPs or their respective metabolites; whereas, a binary oral dose of CPF+DZN at 60+60 mg/kg did result in observable changes in the DZN pharmacokinetics. Cmax was more reasonably fit by modifying the absorption parameters. It is anticipated that at low environmentally relevant binary doses, most likely to be encountered in occupational or environmental related exposures, that the pharmacokinetics are expected to be linear, and ChE inhibition dose-additive.
Asymmetric nuclear matter in a modified quark meson coupling model
International Nuclear Information System (INIS)
Mishra, R.N.; Sahoo, H.S.; Panda, P.K.; Barik, N.
2014-01-01
In an earlier attempt we have successfully used this model in developing the nuclear equation of state and analysed various other bulk properties of symmetric nuclear matter with the dependence of quark masses. In the present work we want to apply the model to analyze asymmetric nuclear matter with the variation of the asymmetry parameter y p as well as analyze the effects of symmetry energy and the slope of the symmetry energy L
Chen, H.; Van der Zwaag, S.
2010-01-01
The soft impingement effect at the later stage of partitioning phase transformations has been modeled both for the diffusion-controlled growth model and for the mixed-mode model. Instead of the linear and exponential approximations for the concentration gradient in front of the interface used in the
Müller, Dirk K; Pampel, André; Möller, Harald E
2013-05-01
Quantification of magnetization-transfer (MT) experiments are typically based on the assumption of the binary spin-bath model. This model allows for the extraction of up to six parameters (relative pool sizes, relaxation times, and exchange rate constants) for the characterization of macromolecules, which are coupled via exchange processes to the water in tissues. Here, an approach is presented for estimating MT parameters acquired with arbitrary saturation schemes and imaging pulse sequences. It uses matrix algebra to solve the Bloch-McConnell equations without unwarranted simplifications, such as assuming steady-state conditions for pulsed saturation schemes or neglecting imaging pulses. The algorithm achieves sufficient efficiency for voxel-by-voxel MT parameter estimations by using a polynomial interpolation technique. Simulations, as well as experiments in agar gels with continuous-wave and pulsed MT preparation, were performed for validation and for assessing approximations in previous modeling approaches. In vivo experiments in the normal human brain yielded results that were consistent with published data. Copyright © 2013 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Rivas, M.A.; Buep, A.H.; Iglesias, T.P.
2015-01-01
Highlights: • Polarization of the real mixture is less than that of the ideal mixture. • Molar excess volume does not exert the dominant effect on the polarization of the mixture. • Similar influence of molecular interactions on the behaviour of excess permittivity. • Excess molar volume is more influenced by the interactions than excess permittivity. - Abstract: Excess molar volumes and excess permittivity of binary mixtures involving monoglyme and alkanes, such as n-hexane, cyclohexane, n-octane and n-dodecane, were calculated from density and relative permittivity measurements for the entire composition range at several temperatures (288.15, 298.15 and 308.15) K and atmospheric pressure. The excess permittivity was calculated on the basis of a recent definition considering the ideal volume fraction. Empirical equations for describing the experimental data in terms of temperature and concentration are given. The experimental values of permittivity have been compared with those estimated by well-known models from literature. The results have indicated that better predictions are obtained when the volume change on mixing is incorporated in these calculations. The contribution of interactions to the excess permittivity was analysed by means of the ECM-average model. The Prigogine–Flory–Patterson (PFP) theory of the thermodynamics of solutions was used to shed light on the contribution of interactions to the excess molar volume. The work concludes with an interpretation of the information given by the theoretical models and the behaviour of both excess magnitudes
Stochastic processes analysis in nuclear reactor using ARMA models
International Nuclear Information System (INIS)
Zavaljevski, N.
1990-01-01
The analysis of ARMA model derived from general stochastic state equations of nuclear reactor is given. The dependence of ARMA model parameters on the main physical characteristics of RB nuclear reactor in Vinca is presented. Preliminary identification results are presented, observed discrepancies between theory and experiment are explained and the possibilities of identification improvement are anticipated. (author)
International Nuclear Information System (INIS)
Fan, Jie-Ping; Zheng, Bing; Liao, Dan-Dan; Yu, Jia-Xin; Cao, Ya-Hui; Zhang, Xue-Hong; Zhu, Jian-Hang
2016-01-01
Highlights: • The solubilities of limonin were measured in the binary solvent mixtures methanol + water and acetone + water. • The solubility data were correlated by nine models. • The solubility of limonin had a maximum point at 0.9 mol fraction of acetone in acetone + water mixtures. - Abstract: The solubility of limonin in the binary solvent mixtures (methanol + water) and (acetone + water) with various initial mole fractions of methanol or acetone was measured by high-performance liquid chromatography (HPLC) at different temperatures ranging from 283.2 K to 318.2 K. The solubility of limonin increased with increasing initial mole fraction of methanol in (methanol + water) mixtures, whereas it had a maximum point at 0.9 mol fraction of acetone in (acetone + water) mixtures. The solubility of limonin increased with increasing temperature in the two binary solvent mixtures. The solubility of limonin was correlated with temperature by the van’t Hoff model and the modified Apelblat model, and the fitting results showed that the modified Apelblat model had better correlation. The CNIBS/Redlich–Kister model and the simplified CNIBS/Redlich–Kister model were used to correlate the solubility data with the initial solvent composition, the results show that the CNIBS/Redlich–Kister model reveals better agreement with the experimental values. Furthermore, to illustrate the effects of both temperature and initial solvent composition on the changes in the solubility of limonin, the solubility values were fitted by the Jouyban–Acree, van’t Hoff–Jouyban–Acree, modified Apelblat–Jouyban–Acree, Ma and Sun models. Among the five models, the Jouyban–Acree model give the best correlation results for (methanol + water) binary solvent mixtures, while the experimental solubility in the (acetone + water) system was most accurately correlated by the van’t Hoff–Jouyban–Acree model.
A fermionic molecular dynamics technique to model nuclear matter
International Nuclear Information System (INIS)
Vantournhout, K.; Jachowicz, N.; Ryckebusch, J.
2009-01-01
Full text: At sub-nuclear densities of about 10 14 g/cm 3 , nuclear matter arranges itself in a variety of complex shapes. This can be the case in the crust of neutron stars and in core-collapse supernovae. These slab like and rod like structures, designated as nuclear pasta, have been modelled with classical molecular dynamics techniques. We present a technique, based on fermionic molecular dynamics, to model nuclear matter at sub-nuclear densities in a semi classical framework. The dynamical evolution of an antisymmetric ground state is described making the assumption of periodic boundary conditions. Adding the concepts of antisymmetry, spin and probability distributions to classical molecular dynamics, brings the dynamical description of nuclear matter to a quantum mechanical level. Applications of this model vary from investigation of macroscopic observables and the equation of state to the study of fundamental interactions on the microscopic structure of the matter. (author)
Modelling human resource requirements for the nuclear industry in Europe
Energy Technology Data Exchange (ETDEWEB)
Roelofs, Ferry [Nuclear Research and Consultancy Group (NRG) (Netherlands); Flore, Massimo; Estorff, Ulrik von [Joint Research Center (JRC) (Netherlands)
2017-11-15
The European Human Resource Observatory for Nuclear (EHRO-N) provides the European Commission with essential data related to supply and demand for nuclear experts in the EU-28 and the enlargement and integration countries based on bottom-up information from the nuclear industry. The objective is to assess how the supply of experts for the nuclear industry responds to the needs for the same experts for present and future nuclear projects in the region. Complementary to the bottom-up approach taken by the EHRO-N team at JRC, a top-down modelling approach has been taken in a collaboration with NRG in the Netherlands. This top-down modelling approach focuses on the human resource requirements for operation, construction, decommissioning, and efforts for long term operation of nuclear power plants. This paper describes the top-down methodology, the model input, the main assumptions, and the results of the analyses.
Experiment research on cognition reliability model of nuclear power plant
International Nuclear Information System (INIS)
Zhao Bingquan; Fang Xiang
1999-01-01
The objective of the paper is to improve the reliability of operation on real nuclear power plant of operators through the simulation research to the cognition reliability of nuclear power plant operators. The research method of the paper is to make use of simulator of nuclear power plant as research platform, to take present international research model of reliability of human cognition based on three-parameter Weibull distribution for reference, to develop and get the research model of Chinese nuclear power plant operators based on two-parameter Weibull distribution. By making use of two-parameter Weibull distribution research model of cognition reliability, the experiments about the cognition reliability of nuclear power plant operators have been done. Compared with the results of other countries such USA and Hungary, the same results can be obtained, which can do good to the safety operation of nuclear power plant
Modelling human resource requirements for the nuclear industry in Europe
International Nuclear Information System (INIS)
Roelofs, Ferry; Flore, Massimo; Estorff, Ulrik von
2017-01-01
The European Human Resource Observatory for Nuclear (EHRO-N) provides the European Commission with essential data related to supply and demand for nuclear experts in the EU-28 and the enlargement and integration countries based on bottom-up information from the nuclear industry. The objective is to assess how the supply of experts for the nuclear industry responds to the needs for the same experts for present and future nuclear projects in the region. Complementary to the bottom-up approach taken by the EHRO-N team at JRC, a top-down modelling approach has been taken in a collaboration with NRG in the Netherlands. This top-down modelling approach focuses on the human resource requirements for operation, construction, decommissioning, and efforts for long term operation of nuclear power plants. This paper describes the top-down methodology, the model input, the main assumptions, and the results of the analyses.
International Nuclear Information System (INIS)
Hou, M.; Ortiz, C.J.; Becquart, C.S.; Domain, C.; Sarkar, U.; Debacker, A.
2010-01-01
It is important to develop an understanding of the evolution of W microstructure the conditions the International Thermonuclear Experimental Reactor (ITER) as well as the DEMOnstration Power Plan (DEMO), and modelling techniques can be very helpful. In this paper, the Binary Collision Approximation of Molecular Dynamics as implemented in the Marlowe code is used to model the slowing down of atomic helium and hydrogen on tungsten in the 1-100 keV range. The computed helium and Frenkel Pairs (FP) distributions are then used as input for the simulation of isochronal annealing experiments with an Object Kinetic Monte Carlo (OKMC) model. Parameterisation is discussed in a companion paper to this one. To model inelastic energy losses beyond the Lindhard regime, a new module has been implemented in the Marlowe code which is presented here, along with a discussion on various parameters of the model important in the modelling of channelled trajectories. For a given total inelastic stopping cross section, large differences in low energy channelling ranges are identified depending on whether inelastic energy loss is considered to be purely continuous or to also occur during the atomic collisions. In polycrystals, the channelling probability is shown to be significant over the whole range of slowing down energies considered. Channelling together with short replacement sequences has the effect of reducing the FP production efficiency by more than a factor two in polycrystalline as compared with an hypothetical structureless tungsten. This has a crucial effect on the helium isochronal desorption spectra predicted by the OKMC simulations. Those predicted with structureless tungsten are at variance with experiment, due to the overestimation of He trapping on the radiation induced defects.
Energy Technology Data Exchange (ETDEWEB)
Hou, M., E-mail: mhou@ulb.ac.b [Physique des Solides Irradies et des Nanostructures CP234, Universite Libre de Bruxelles, Bd du Triomphe, B-1050 Brussels (Belgium); Ortiz, C.J. [Laboratorio Nacional de Fusion por Confinamiento Magnetico, CIEMAT, E-28040 Madrid (Spain); Becquart, C.S. [Unite Materiaux Et Transformations (UMET), UMR 8207, Universite de Lille 1, F-59655 Villeneuve d' Ascq Cedex (France); Domain, C. [EDF-R and D Departement MMC, Les Renardieres, F-77818 Moret sur Loing Cedex (France); Sarkar, U. [Physics Department, Assam University, Silchar (India); Debacker, A. [Unite Materiaux Et Transformations (UMET), UMR 8207, Universite de Lille 1, F-59655 Villeneuve d' Ascq Cedex (France)
2010-08-15
It is important to develop an understanding of the evolution of W microstructure the conditions the International Thermonuclear Experimental Reactor (ITER) as well as the DEMOnstration Power Plan (DEMO), and modelling techniques can be very helpful. In this paper, the Binary Collision Approximation of Molecular Dynamics as implemented in the Marlowe code is used to model the slowing down of atomic helium and hydrogen on tungsten in the 1-100 keV range. The computed helium and Frenkel Pairs (FP) distributions are then used as input for the simulation of isochronal annealing experiments with an Object Kinetic Monte Carlo (OKMC) model. Parameterisation is discussed in a companion paper to this one. To model inelastic energy losses beyond the Lindhard regime, a new module has been implemented in the Marlowe code which is presented here, along with a discussion on various parameters of the model important in the modelling of channelled trajectories. For a given total inelastic stopping cross section, large differences in low energy channelling ranges are identified depending on whether inelastic energy loss is considered to be purely continuous or to also occur during the atomic collisions. In polycrystals, the channelling probability is shown to be significant over the whole range of slowing down energies considered. Channelling together with short replacement sequences has the effect of reducing the FP production efficiency by more than a factor two in polycrystalline as compared with an hypothetical structureless tungsten. This has a crucial effect on the helium isochronal desorption spectra predicted by the OKMC simulations. Those predicted with structureless tungsten are at variance with experiment, due to the overestimation of He trapping on the radiation induced defects.
A Nuclear Waste Management Cost Model for Policy Analysis
Barron, R. W.; Hill, M. C.
2017-12-01
Although integrated assessments of climate change policy have frequently identified nuclear energy as a promising alternative to fossil fuels, these studies have often treated nuclear waste disposal very simply. Simple assumptions about nuclear waste are problematic because they may not be adequate to capture relevant costs and uncertainties, which could result in suboptimal policy choices. Modeling nuclear waste management costs is a cross-disciplinary, multi-scale problem that involves economic, geologic and environmental processes that operate at vastly different temporal scales. Similarly, the climate-related costs and benefits of nuclear energy are dependent on environmental sensitivity to CO2 emissions and radiation, nuclear energy's ability to offset carbon emissions, and the risk of nuclear accidents, factors which are all deeply uncertain. Alternative value systems further complicate the problem by suggesting different approaches to valuing intergenerational impacts. Effective policy assessment of nuclear energy requires an integrated approach to modeling nuclear waste management that (1) bridges disciplinary and temporal gaps, (2) supports an iterative, adaptive process that responds to evolving understandings of uncertainties, and (3) supports a broad range of value systems. This work develops the Nuclear Waste Management Cost Model (NWMCM). NWMCM provides a flexible framework for evaluating the cost of nuclear waste management across a range of technology pathways and value systems. We illustrate how NWMCM can support policy analysis by estimating how different nuclear waste disposal scenarios developed using the NWMCM framework affect the results of a recent integrated assessment study of alternative energy futures and their effects on the cost of achieving carbon abatement targets. Results suggest that the optimism reflected in previous works is fragile: Plausible nuclear waste management costs and discount rates appropriate for intergenerational cost
MODELLING OF NUCLEAR POWER PLANT DECOMMISSIONING FINANCING
Czech Academy of Sciences Publication Activity Database
Bemš, J.; Knápek, J.; Králík, T.; Hejhal, M.; Kubančák, Ján; Vašíček, J.
2015-01-01
Roč. 164, č. 4 (2015), s. 519-522 ISSN 0144-8420 Institutional support: RVO:61389005 Keywords : nuclear power plant * methodology * future decommissioning costs Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.894, year: 2015
Aggregated systems model for nuclear safeguards decisions
International Nuclear Information System (INIS)
1979-03-01
This report summarizes a general analytical tool designed to assist nuclear safeguards decision-makers. The approach is based on decision analysis--a quantitative procedure for evaluating complex decision alternatives with uncertain outcomes. The report describes the general analytical approach in the context of safeguards decisions at a hypothetical nuclear fuel reprocessing plant
Modelling of nuclear power plant decommissioning financing.
Bemš, J; Knápek, J; Králík, T; Hejhal, M; Kubančák, J; Vašíček, J
2015-06-01
Costs related to the decommissioning of nuclear power plants create a significant financial burden for nuclear power plant operators. This article discusses the various methodologies employed by selected European countries for financing of the liabilities related to the nuclear power plant decommissioning. The article also presents methodology of allocation of future decommissioning costs to the running costs of nuclear power plant in the form of fee imposed on each megawatt hour generated. The application of the methodology is presented in the form of a case study on a new nuclear power plant with installed capacity 1000 MW. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
New Flexible Models and Design Construction Algorithms for Mixtures and Binary Dependent Variables
A. Ruseckaite (Aiste)
2017-01-01
markdownabstractThis thesis discusses new mixture(-amount) models, choice models and the optimal design of experiments. Two chapters of the thesis relate to the so-called mixture, which is a product or service whose ingredients’ proportions sum to one. The thesis begins by introducing mixture
Del Pozzo, W.; Berry, C. P. L.; Ghosh, A.; Haines, T. S. F.; Singer, L. P.; Vecchio, A.
2018-06-01
We reconstruct posterior distributions for the position (sky area and distance) of a simulated set of binary neutron-star gravitational-waves signals observed with Advanced LIGO and Advanced Virgo. We use a Dirichlet Process Gaussian-mixture model, a fully Bayesian non-parametric method that can be used to estimate probability density functions with a flexible set of assumptions. The ability to reliably reconstruct the source position is important for multimessenger astronomy, as recently demonstrated with GW170817. We show that for detector networks comparable to the early operation of Advanced LIGO and Advanced Virgo, typical localization volumes are ˜104-105 Mpc3 corresponding to ˜102-103 potential host galaxies. The localization volume is a strong function of the network signal-to-noise ratio, scaling roughly ∝ϱnet-6. Fractional localizations improve with the addition of further detectors to the network. Our Dirichlet Process Gaussian-mixture model can be adopted for localizing events detected during future gravitational-wave observing runs, and used to facilitate prompt multimessenger follow-up.
Kim, Y. W.; Cress, R. P.
2016-11-01
Disordered binary alloys are modeled as a randomly close-packed assembly of nanocrystallites intermixed with randomly positioned atoms, i.e., glassy-state matter. The nanocrystallite size distribution is measured in a simulated macroscopic medium in two dimensions. We have also defined, and measured, the degree of crystallinity as the probability of a particle being a member of nanocrystallites. Both the distribution function and the degree of crystallinity are found to be determined by alloy composition. When heated, the nanocrystallites become smaller in size due to increasing thermal fluctuation. We have modeled this phenomenon as a case of thermal dissociation by means of the law of mass action. The crystallite size distribution function is computed for AuCu3 as a function of temperature by solving some 12 000 coupled algebraic equations for the alloy. The results show that linear thermal expansion of the specimen has contributions from the temperature dependence of the degree of crystallinity, in addition to respective thermal expansions of the nanocrystallites and glassy-state matter.
Xie, Xianhong; Xue, Xiaonan; Strickler, Howard D
2018-01-15
Longitudinal measurement of biomarkers is important in determining risk factors for binary endpoints such as infection or disease. However, biomarkers are subject to measurement error, and some are also subject to left-censoring due to a lower limit of detection. Statistical methods to address these issues are few. We herein propose a generalized linear mixed model and estimate the model parameters using the Monte Carlo Newton-Raphson (MCNR) method. Inferences regarding the parameters are made by applying Louis's method and the delta method. Simulation studies were conducted to compare the proposed MCNR method with existing methods including the maximum likelihood (ML) method and the ad hoc approach of replacing the left-censored values with half of the detection limit (HDL). The results showed that the performance of the MCNR method is superior to ML and HDL with respect to the empirical standard error, as well as the coverage probability for the 95% confidence interval. The HDL method uses an incorrect imputation method, and the computation is constrained by the number of quadrature points; while the ML method also suffers from the constrain for the number of quadrature points, the MCNR method does not have this limitation and approximates the likelihood function better than the other methods. The improvement of the MCNR method is further illustrated with real-world data from a longitudinal study of local cervicovaginal HIV viral load and its effects on oncogenic HPV detection in HIV-positive women. Copyright © 2017 John Wiley & Sons, Ltd.
Zhu, Guangpu
2018-04-17
In this paper, we consider the numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow. The nonlinearly coupled model consists of two Cahn-Hilliard type equations and incompressible Navier-Stokes equations. Using the Invariant Energy Quadratization (IEQ) approach, the governing system is transformed into an equivalent form, which allows the nonlinear potentials to be treated efficiently and semi-explicitly. we construct a first and a second-order time marching schemes, which are extremely efficient and easy-to-implement, for the transformed governing system. At each time step, the schemes involve solving a sequence of linear elliptic equations, and computations of phase variables, velocity and pressure are totally decoupled. We further establish a rigorous proof of unconditional energy stability for the semi-implicit schemes. Numerical results in both two and three dimensions are obtained, which demonstrate that the proposed schemes are accurate, efficient and unconditionally energy stable. Using our schemes, we investigate the effect of surfactants on droplet deformation and collision under a shear flow. The increase of surfactant concentration can enhance droplet deformation and inhibit droplet coalescence.
Zhu, Guangpu; Kou, Jisheng; Sun, Shuyu; Yao, Jun; Li, Aifen
2018-01-01
In this paper, we consider the numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow. The nonlinearly coupled model consists of two Cahn-Hilliard type equations and incompressible Navier-Stokes equations. Using the Invariant Energy Quadratization (IEQ) approach, the governing system is transformed into an equivalent form, which allows the nonlinear potentials to be treated efficiently and semi-explicitly. we construct a first and a second-order time marching schemes, which are extremely efficient and easy-to-implement, for the transformed governing system. At each time step, the schemes involve solving a sequence of linear elliptic equations, and computations of phase variables, velocity and pressure are totally decoupled. We further establish a rigorous proof of unconditional energy stability for the semi-implicit schemes. Numerical results in both two and three dimensions are obtained, which demonstrate that the proposed schemes are accurate, efficient and unconditionally energy stable. Using our schemes, we investigate the effect of surfactants on droplet deformation and collision under a shear flow. The increase of surfactant concentration can enhance droplet deformation and inhibit droplet coalescence.
Directory of Open Access Journals (Sweden)
Di Fang
Full Text Available Recent advances in statistical methods enable the study of correlation among outcomes through joint modeling, thereby addressing spillover effects. By joint modeling, we refer to simultaneously analyzing two or more different response variables emanating from the same individual. Using the 2011 Bangladesh Demographic and Health Survey, we jointly address spillover effects between contraceptive use (CUC and knowledge of HIV and other sexually transmitted diseases. Jointly modeling these two outcomes is appropriate because certain types of contraceptive use contribute to the prevention of HIV and STDs and the knowledge and awareness of HIV and STDs typically lead to protection during sexual intercourse. In particular, we compared the differences as they pertained to the interpretive advantage of modeling the spillover effects of joint modeling HIV and CUC as opposed to addressing them separately. We also identified risk factors that determine contraceptive use and knowledge of HIV and STDs among women in Bangladesh. We found that by jointly modeling the correlation between HIV knowledge and contraceptive use, the importance of education decreased. The HIV prevention program had a spillover effect on CUC: what seemed to be impacted by education can be partially contributed to one's exposure to HIV knowledge. The joint model revealed a less significant impact of covariates as opposed to both separate models and standard models. Additionally, we found a spillover effect that would have otherwise been undiscovered if we did not jointly model. These findings further suggested that the simultaneous impact of correlated outcomes can be adequately addressed for the commonality between different responses and deflate, which is otherwise overestimated when examined separately.
Coevolution of Binaries and Circumbinary Gaseous Disks
Fleming, David; Quinn, Thomas R.
2018-04-01
The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.
Modeling fabrication of nuclear components: An integrative approach
Energy Technology Data Exchange (ETDEWEB)
Hench, K.W.
1996-08-01
Reduction of the nuclear weapons stockpile and the general downsizing of the nuclear weapons complex has presented challenges for Los Alamos. One is to design an optimized fabrication facility to manufacture nuclear weapon primary components in an environment of intense regulation and shrinking budgets. This dissertation presents an integrative two-stage approach to modeling the casting operation for fabrication of nuclear weapon primary components. The first stage optimizes personnel radiation exposure for the casting operation layout by modeling the operation as a facility layout problem formulated as a quadratic assignment problem. The solution procedure uses an evolutionary heuristic technique. The best solutions to the layout problem are used as input to the second stage - a simulation model that assesses the impact of competing layouts on operational performance. The focus of the simulation model is to determine the layout that minimizes personnel radiation exposures and nuclear material movement, and maximizes the utilization of capacity for finished units.
A sample application of nuclear power human resources model
International Nuclear Information System (INIS)
Gurgen, A.; Ergun, S.
2016-01-01
One of the most important issues for a new comer country initializing the nuclear power plant projects is to have both quantitative and qualitative models for the human resources development. For the quantitative model of human resources development for Turkey, “Nuclear Power Human Resources (NPHR) Model” developed by the Los Alamos National Laboratory was used to determine the number of people that will be required from different professional or occupational fields in the planning of human resources for Akkuyu, Sinop and the third nuclear power plant projects. The number of people required for different professions for the Nuclear Energy Project Implementation Department, the regulatory authority, project companies, construction, nuclear power plants and the academy were calculated. In this study, a sample application of the human resources model is presented. The results of the first tries to calculate the human resources needs of Turkey were obtained. Keywords: Human Resources Development, New Comer Country, NPHR Model
Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems
Czech Academy of Sciences Publication Activity Database
Svoboda, Jiří; Fischer, F. D.
2014-01-01
Roč. 22, č. 1 (2014), Art . No. 015013 ISSN 0965-0393 Institutional support: RVO:68081723 Keywords : grain boundary segregation * abnormal grain growth * theory * modelling * solute drag Subject RIV: BJ - Thermodynamics Impact factor: 2.167, year: 2014
Directory of Open Access Journals (Sweden)
Araceli Sanchis
2013-04-01
Full Text Available Activities of daily living are good indicators of elderly health status, and activity recognition in smart environments is a well-known problem that has been previously addressed by several studies. In this paper, we describe the use of two powerful machine learning schemes, ANN (Artificial Neural Network and SVM (Support Vector Machines, within the framework of HMM (Hidden Markov Model in order to tackle the task of activity recognition in a home setting. The output scores of the discriminative models, after processing, are used as observation probabilities of the hybrid approach. We evaluate our approach by comparing these hybrid models with other classical activity recognition methods using five real datasets. We show how the hybrid models achieve significantly better recognition performance, with significance level p < 0:05, proving that the hybrid approach is better suited for the addressed domain.
Modeling of Pu(IV) extraction and HNO3 speciation in nuclear fuel reprocessing
International Nuclear Information System (INIS)
De-Sio, S.
2012-01-01
The PUREX process is a solvent extraction method dedicated to the reprocessing of irradiated nuclear fuel in order to recover pure uranium and plutonium from aqueous solutions of concentrated nitric acid. The tri-n-butylphosphate (TBP) is used as the extractant in the organic phase. The aim of this thesis work was to improve the modeling of liquid-liquid extraction media in nuclear fuel reprocessing. First, Raman and 14 N NMR measurements, coupled with theoretical calculations based on simple solutions theory and BIMSA modeling, were performed in order to get a better understanding of nitric acid dissociation in binary and ternary solutions. Then, Pu(IV) speciation in TBP after extraction from low nitric acid concentrations was investigated by EXAFS and vis-NIR spectroscopies. We were able to show evidence of the extraction of Pu(IV) hydrolyzed species into the organic phase. A new structural study was conducted on An(VI)/TBP and An(IV)/TBP complexes by coupling EXAFS measurements with DFT calculations. Finally, extraction isotherms modeling was performed on the Pu(IV)/HNO 3 /H 2 O/TBP 30%/dodecane system (with Pu at tracer scale) by taking into account deviation from ideal behaviour in both organic and aqueous phases. The best modeling was obtained when considering three plutonium (IV) complexes in the organic phase: Pu(OH) 2 (NO 3 ) 2 (TBP) 2 , Pu(NO 3 ) 4 (TBP) 2 and Pu(NO 3 ) 4 (TBP) 3 . (author) [fr
Combining phase-field crystal methods with a Cahn-Hilliard model for binary alloys
Balakrishna, Ananya Renuka; Carter, W. Craig
2018-04-01
Diffusion-induced phase transitions typically change the lattice symmetry of the host material. In battery electrodes, for example, Li ions (diffusing species) are inserted between layers in a crystalline electrode material (host). This diffusion induces lattice distortions and defect formations in the electrode. The structural changes to the lattice symmetry affect the host material's properties. Here, we propose a 2D theoretical framework that couples a Cahn-Hilliard (CH) model, which describes the composition field of a diffusing species, with a phase-field crystal (PFC) model, which describes the host-material lattice symmetry. We couple the two continuum models via coordinate transformation coefficients. We introduce the transformation coefficients in the PFC method to describe affine lattice deformations. These transformation coefficients are modeled as functions of the composition field. Using this coupled approach, we explore the effects of coarse-grained lattice symmetry and distortions on a diffusion-induced phase transition process. In this paper, we demonstrate the working of the CH-PFC model through three representative examples: First, we describe base cases with hexagonal and square symmetries for two composition fields. Next, we illustrate how the CH-PFC method interpolates lattice symmetry across a diffuse phase boundary. Finally, we compute a Cahn-Hilliard type of diffusion and model the accompanying changes to lattice symmetry during a phase transition process.
Sedimentary modelling and nuclear-waste disposal
International Nuclear Information System (INIS)
Van Loon, A.J.
1982-01-01
Nuclear energy is an important source of energy. Recently a slow down is experienced in its growth rate, due to the following factors: a) the supposed shortage of uranium; b) the fear for the consequences of nuclear accident, and c) the problem of nuclear wastes. Two types of waste are distinguished: a) fission products and actinides, and b) operational waste. The United States have started a program that must lead in 1989 to the first final storage of such waste in salt. Open-pit mines and oil-well drilling are discussed as possible solutions for operational waste storage
The Nuclear Shell Model and its Relation with Other Nuclear Models
Energy Technology Data Exchange (ETDEWEB)
Elliott, J. P. [University of Sussex, Brighton (United Kingdom)
1963-01-15
The starting point of all versions of the shell model is the physical idea that the interaction between a given nucleon and all the others resembles that between a nucleon and a fixed field. From this starting point one might attempt to construct a field which is self-consistent but this approach is not followed in most shell-model calculations because of the complications that arise. The more usual approach has been to use the idea of an average field to provide a complete set of sin gle-particle wave functions. Then, if the parameters of the field (e.g. its size) are correctly chosen, we would expect to reach a good approximation to the nuclear-wave function by taking that configuration of single-particle wave functions which has lowest energy in this field. The wave functions could clearly be improved by allowing the mixing of excited configurations but this is rarely done because of the resulting complexity of the problem. Even in the lowest configuration there are in general many independent wave functions for a many-particle system which would all be degenerate in the average field. To find the nuclear energy levels and wave functions we must therefore build up the energy matrix in this degenerate set, using the inter-nucleon two-body forces, and then diagonalize this matrix. If the detailed form of the nuclear forces was known we might regard such calculations as the first step towards an exact calculation in which higher configurations were included but every indication is that the convergence would be extremely slow. It is more usual to treat an energy calculation in the lowest configuration unashamedly as a model calculation and to attempt to deduce, by comparisons with experimental data in the many-particle nuclei, the nature of the effective nuclear forces required in that configuration. If the model is realistic then we should not expect these effective forces to change very much in going from one nucleus to its neighbour and since there are many more
Influence of non-binary effects on intranuclear cascade method
International Nuclear Information System (INIS)
Gomes, E.H.C.
1985-01-01
The importance of non binary process effects in the intranuclear cascade method is analysed. It is shown that, in the higher density steps, the non binary collisions lead to baryon density distribution and rapidity differents from the one obtained using the usual intranuclear cascade method (limited to purely binary collisions). The validity of the applications of binary intranuclear cascade method to the simulation of the thermal equilibrium, nuclear transparency and particle production, is discussed. (M.C.K.) [pt
Development of Dynamic Spent Nuclear Fuel Environmental Effect Analysis Model
International Nuclear Information System (INIS)
Jeong, Chang Joon; Ko, Won Il; Lee, Ho Hee; Cho, Dong Keun; Park, Chang Je
2010-07-01
The dynamic environmental effect evaluation model for spent nuclear fuel has been developed and incorporated into the system dynamic DANESS code. First, the spent nuclear fuel isotope decay model was modeled. Then, the environmental effects were modeled through short-term decay heat model, short-term radioactivity model, and long-term heat load model. By using the developed model, the Korean once-through nuclear fuel cycles was analyzed. The once-through fuel cycle analysis was modeled based on the Korean 'National Energy Basic Plan' up to 2030 and a postulated nuclear demand growth rate until 2150. From the once-through results, it is shown that the nuclear power demand would be ∼70 GWe and the total amount of the spent fuel accumulated by 2150 would be ∼168000 t. If the disposal starts from 2060, the short-term decay heat of Cs-137 and Sr-90 isotopes are W and 1.8x10 6 W in 2100. Also, the total long-term heat load in 2100 will be 4415 MW-y. From the calculation results, it was found that the developed model is very convenient and simple for evaluation of the environmental effect of the spent nuclear fuel
International Nuclear Information System (INIS)
Amore, S.; Brillo, J.; Egry, I.; Novakovic, R.
2011-01-01
The surface tension of liquid Cu-Ti alloys has been measured by using the containerless technique of electromagnetic levitation and theoretically calculated in the framework of the compound formation model. Measurements have been carried out on alloys covering the entire range of composition and over the temperature range 1275-2050 K. For all investigated alloys the surface tension can be described by a linear function of the temperature with negative slope. Due to the presence of different intermetallic compounds in the solid state the surface properties of liquid Cu-Ti alloys are satisfactory described by the compound formation model.
The two bands model for the high temperature conductivity of the binary rare earth alloys
International Nuclear Information System (INIS)
Borgiel, W.
1983-09-01
The formula for the high temperature spin disorder resistivity for the concentrated Asub(1-x)Bsub(x)C alloys where A,B is an element of Rare Earth (RE) is determined on the basis of two bands model and the coherent potential approximation (CPA). The conductivity given by the 5d bands coming from the RE compounds has been taken into account
Thermophysical Modeling of Contact Binary Near-Earth Asteroid 1996 HW1
Magri, C.; Howell, E. S.; Nolan, M. C.; Taylor, P. A.; Fernández, Y. R.; Mueller, M.; Rivkin, A. S.; Vervack, R. J., Jr.
2011-01-01
Near-Earth asteroid (8567) 1996 HW1 was observed spectroscopically at 1.9-4.0 microns during August- October 2008 using the SpeX instrument at NASA's Infrared Telescope Facility (IRTF). These spectra are being modeled using a new thermophysical program that accounts for the object's spin orientation
A new self-consistent model for thermodynamics of binary solutions
Czech Academy of Sciences Publication Activity Database
Svoboda, Jiří; Shan, Y. V.; Fischer, F. D.
2015-01-01
Roč. 108, NOV (2015), s. 27-30 ISSN 1359-6462 R&D Projects: GA ČR(CZ) GA14-24252S Institutional support: RVO:68081723 Keywords : Thermodynamics * Analytical methods * CALPHAD * Phase diagram * Self-consistent model Subject RIV: BJ - Thermodynamics Impact factor: 3.305, year: 2015
Proof of concept and dose estimation with binary responses under model uncertainty.
Klingenberg, B
2009-01-30
This article suggests a unified framework for testing Proof of Concept (PoC) and estimating a target dose for the benefit of a more comprehensive, robust and powerful analysis in phase II or similar clinical trials. From a pre-specified set of candidate models, we choose the ones that best describe the observed dose-response. To decide which models, if any, significantly pick up a dose effect, we construct the permutation distribution of the minimum P-value over the candidate set. This allows us to find critical values and multiplicity adjusted P-values that control the familywise error rate of declaring any spurious effect in the candidate set as significant. Model averaging is then used to estimate a target dose. Popular single or multiple contrast tests for PoC, such as the Cochran-Armitage, Dunnett or Williams tests, are only optimal for specific dose-response shapes and do not provide target dose estimates with confidence limits. A thorough evaluation and comparison of our approach to these tests reveal that its power is as good or better in detecting a dose-response under various shapes with many more additional benefits: It incorporates model uncertainty in PoC decisions and target dose estimation, yields confidence intervals for target dose estimates and extends to more complicated data structures. We illustrate our method with the analysis of a Phase II clinical trial. Copyright (c) 2008 John Wiley & Sons, Ltd.
Binary classifiers and latent sequence models for emotion detection in suicide notes.
Cherry, Colin; Mohammad, Saif M; de Bruijn, Berry
2012-01-01
This paper describes the National Research Council of Canada's submission to the 2011 i2b2 NLP challenge on the detection of emotions in suicide notes. In this task, each sentence of a suicide note is annotated with zero or more emotions, making it a multi-label sentence classification task. We employ two distinct large-margin models capable of handling multiple labels. The first uses one classifier per emotion, and is built to simplify label balance issues and to allow extremely fast development. This approach is very effective, scoring an F-measure of 55.22 and placing fourth in the competition, making it the best system that does not use web-derived statistics or re-annotated training data. Second, we present a latent sequence model, which learns to segment the sentence into a number of emotion regions. This model is intended to gracefully handle sentences that convey multiple thoughts and emotions. Preliminary work with the latent sequence model shows promise, resulting in comparable performance using fewer features.
Nuclear spin noise in the central spin model
Fröhling, Nina; Anders, Frithjof B.; Glazov, Mikhail
2018-05-01
We study theoretically the fluctuations of the nuclear spins in quantum dots employing the central spin model which accounts for the hyperfine interaction of the nuclei with the electron spin. These fluctuations are calculated both with an analytical approach using homogeneous hyperfine couplings (box model) and with a numerical simulation using a distribution of hyperfine coupling constants. The approaches are in good agreement. The box model serves as a benchmark with low computational cost that explains the basic features of the nuclear spin noise well. We also demonstrate that the nuclear spin noise spectra comprise a two-peak structure centered at the nuclear Zeeman frequency in high magnetic fields with the shape of the spectrum controlled by the distribution of the hyperfine constants. This allows for direct access to this distribution function through nuclear spin noise spectroscopy.
The symbiotics as binary stars
International Nuclear Information System (INIS)
Plavec, M.J.
1982-01-01
The author envisages at least three models that can give a symbiotic object: He has called them, respectively, the PN symbiotic, the Algol symbiotic, and the novalike symbiotic. Their properties are briefly discussed. The most promising model is one of a binary system in the second stage of mass transfer, actually at the beginning of it: The cool component is a red giant ascending the asymptotic branch, expanding but not yet filling its critical lobe. The hot star is a subdwarf located in the same region of the Hertzsprung-Russell diagram as the central stars of planetary nebulae. It may be closely related to them, or it may be a helium star, actually a remnant of an Algol primary which underwent the first stage of mass transfer. In these cases, accretion on this star may not play a significant role (PN symbiotic). Perhaps more often, the subdwarf is a ''rejuvenated'' degenerate dwarf whose nuclear burning shells were ignited and are maintained by accretion of material coming from the red giant in the form of a stellar wind. Eruptions are often inevitable: this is the novalike symbiotic. A third alternative is a system in the first stage of mass transfer, where the photons needed for ionization of the nebula come from an accretion disk surrounding a main sequence star: an Algol symbiotic. In spite of considerable observational effort, the symbiotics are known so poorly that it is hard to decide between the models, or even decide if all three can actually exist. (Auth.)
International Nuclear Information System (INIS)
Morales, Juan Carlos; Torres, Guillermo; Marschall, Laurence A.; Brehm, William
2009-01-01
We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IM Vir, composed of a G7-type primary and a K7 secondary. With these observations, we derive accurate absolute masses and radii of M 1 = 0.981 ± 0.012 M sun , M 2 = 0.6644 ± 0.0048 M sun , R 1 = 1.061 ± 0.016 R sun , and R 2 = 0.681 ± 0.013 R sun for the primary and secondary, with relative errors under 2%. The effective temperatures are 5570 ± 100 K and 4250 ± 130 K, respectively. The significant difference in mass makes this a favorable case for comparison with stellar evolution theory. We find that both stars are larger than the models predict, by 3.7% for the primary and 7.5% for the secondary, as well as cooler than expected, by 100 K and 150 K, respectively. These discrepancies are in line with previously reported differences in low-mass stars, and are believed to be caused by chromospheric activity, which is not accounted for in current models. The effect is not confined to low-mass stars: the rapidly rotating primary of IM Vir joins the growing list of objects of near-solar mass (but still with convective envelopes) that show similar anomalies. The comparison with the models suggests an age of 2.4 Gyr for the system, and a metallicity of [Fe/H] ∼-0.3 that is consistent with other indications, but requires confirmation.
Directory of Open Access Journals (Sweden)
Irfan Hussain
2018-06-01
Full Text Available This research work aims at realizing a new compliant robotic actuator for safe human-robotic interaction. In this paper, we present the modeling, control, and numerical simulations of a novel Binary-Controlled Variable Stiffness Actuator (BcVSA aiming to be used for the development of a novel compliant robotic manipulator. BcVSA is the proof of concept of the active revolute joint with the variable recruitment of series-parallel elastic elements. We briefly recall the basic design principle which is based on a stiffness varying mechanism consisting of a motor, three inline clutches, and three torsional springs with stiffness values (K0, 2K0, 4K0 connected to the load shaft and the motor shaft through two planetary sun gear trains with ratios (4:1, 4:1 respectively. We present the design concept, stiffness and dynamic modeling, and control of our BcVSA. We implemented three kinds of Multiple Model Predictive Control (MPC to control our actuator. The main motivation of choosing this controller lies in the fact that working principle of multiple MPC and multiple states space representation (stiffness level of our actuator share similar interests. In particular, we implemented Multiple MPC, Multiple Explicit MPC, and Approximated Multiple Explicit MPC. Numerical simulations are performed in order to evaluate their effectiveness for the future experiments on the prototype of our actuator. The simulation results showed that the Multiple MPC, and the Multiple Explicit MPC have similar results from the robustness point of view. On the other hand, the robustness performance of Approximated Multiple Explicit MPC is not good as compared to other controllers but it works in the offline framework while having the capability to compute the sub-optimal results. We also performed the comparison of MPC based controllers with the Computed Torque Control (CTC, and Linear Quadratic Regulator (LQR. In future, we are planning to test the presented approach on the
GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE
Energy Technology Data Exchange (ETDEWEB)
Holley-Bockelmann, Kelly [Vanderbilt University, Nashville, TN (United States); Khan, Fazeel Mahmood, E-mail: k.holley@vanderbilt.edu [Institute of Space Technology (IST), Islamabad (Pakistan)
2015-09-10
Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.
GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE
International Nuclear Information System (INIS)
Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood
2015-01-01
Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy
Directory of Open Access Journals (Sweden)
Igor KOLESNIKOV
2016-12-01
Full Text Available Serviceability of metal-polymeric "dry-friction" sliding bearings depends on many parameters, including the rotational speed, friction coefficient, thermal and mechanical properties of the bearing system and, as a result, the value of contact temperature. The objective of this study is to develop a computational model for the metallic-polymer bearing, determination on the basis of this model temperature distribution, equivalent and contact stresses for elements of the bearing arrangement and selection of the optimal parameters for the bearing system to achieve thermal balance. Static problem for the combined sliding bearing with the account of heat generation due to friction has been studied in [1]; the dynamic thermoelastic problem of the shaft rotation in a single and double layer bronze bearings were investigated in [2, 3].
On weak solutions to a diffuse interface model of a binary mixture of compressible fluids
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard
2016-01-01
Roč. 9, č. 1 (2016), s. 173-183 ISSN 1937-1632 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : Euler-Cahn-Hilliard system * weak solution * diffuse interface model Subject RIV: BA - General Mathematics Impact factor: 0.781, year: 2016 http://aimsciences.org/journals/displayArticlesnew.jsp?paperID=12093
The glass model of Muelheim-Kaerlich nuclear power station
International Nuclear Information System (INIS)
Kuttruf, H.; Lemke, W.
1986-01-01
The glass model represents the nuclear steam generator system of Muelheim-Kaerlich nuclear power station on a scale of 1:25 and in simplified form, so that the thermohydraulic behaviour in both normal operational and fault conditions can be represented. A set-up time of about one hour results in a helpful aid to instruction. (orig.) [de
Chaotic behaviour of the nuclear shell-model hamiltonian
International Nuclear Information System (INIS)
Dias, H.; Hussein, M.S.; Oliveira, N.A. de; Wildenthal, B.H.
1987-11-01
Large scale nuclear shell-model calculations for several nuclear systems are discussed. In particular, the statistical baheviour of the energy eigenvalues and eigenstates, are discussed. The chaotic behaviour of the NSMH is then shown to be quite useful in calculating the spreading width of the highly collective multipole giant resonances. (author) [pt
Nuclear model codes available at the Nuclear Energy Agency Computer Program Library (NEA-CPL)
International Nuclear Information System (INIS)
Sartori, E.; Garcia Viedma, L. de
1976-01-01
This paper briefly outlines the objectives of the NEA-CPL and its activities in the field of Nuclear Model Computer Codes. A short description of the computer codes available from the CPL in this field is also presented. (author)
Maria Jose, Gonzalez Torres; Jürgen, Henniger
2018-01-01
In order to expand the Monte Carlo transport program AMOS to particle therapy applications, the ion module is being developed in the radiation physics group (ASP) at the TU Dresden. This module simulates the three main interactions of ions in matter for the therapy energy range: elastic scattering, inelastic collisions and nuclear reactions. The simulation of the elastic scattering is based on the Binary Collision Approximation and the inelastic collisions on the Bethe-Bloch theory. The nuclear reactions, which are the focus of the module, are implemented according to a probabilistic-based model developed in the group. The developed model uses probability density functions to sample the occurrence of a nuclear reaction given the initial energy of the projectile particle as well as the energy at which this reaction will take place. The particle is transported until the reaction energy is reached and then the nuclear reaction is simulated. This approach allows a fast evaluation of the nuclear reactions. The theory and application of the proposed model will be addressed in this presentation. The results of the simulation of a proton beam colliding with tissue will also be presented. Copyright © 2017.
Building better optical model potentials for nuclear astrophysics applications
International Nuclear Information System (INIS)
Bauge, Eric; Dupuis, Marc
2004-01-01
In nuclear astrophysics, optical model potentials play an important role, both in the nucleosynthesis models, and in the interpretation of astrophysics related nuclear physics measurements. The challenge of nuclear astrophysics resides in the fact that it involves many nuclei far from the stability line, implying than very few (if any) experimental results are available for these nuclei. The answer to this challenge is a heavy reliance on microscopic optical models with solid microscopic physics foundations that can predict the relevant physical quantities with good accuracy. This use of microscopic information limits the likelihood of the model failing spectacularly (except if some essential physics was omitted in the modeling) when extrapolating away from the stability line, in opposition to phenomenological models which are only suited for interpolation between measured data points and not for extrapolating towards unexplored areas of the chart of the nuclides.We will show how these microscopic optical models are built, how they link to our present knowledge of nuclear structure, and how they affect predictions of nuclear astrophysics models and the interpretation of some key nuclear physics measurements for astrophysics
Covariance matrices for nuclear cross sections derived from nuclear model calculations
International Nuclear Information System (INIS)
Smith, D. L.
2005-01-01
The growing need for covariance information to accompany the evaluated cross section data libraries utilized in contemporary nuclear applications is spurring the development of new methods to provide this information. Many of the current general purpose libraries of evaluated nuclear data used in applications are derived either almost entirely from nuclear model calculations or from nuclear model calculations benchmarked by available experimental data. Consequently, a consistent method for generating covariance information under these circumstances is required. This report discusses a new approach to producing covariance matrices for cross sections calculated using nuclear models. The present method involves establishing uncertainty information for the underlying parameters of nuclear models used in the calculations and then propagating these uncertainties through to the derived cross sections and related nuclear quantities by means of a Monte Carlo technique rather than the more conventional matrix error propagation approach used in some alternative methods. The formalism to be used in such analyses is discussed in this report along with various issues and caveats that need to be considered in order to proceed with a practical implementation of the methodology
Multiscale modeling of θ' precipitation in Al-Cu binary alloys
International Nuclear Information System (INIS)
Vaithyanathan, V.; Wolverton, C.; Chen, L.Q.
2004-01-01
We present a multiscale model for studying the growth and coarsening of θ' precipitates in Al-Cu alloys. Our approach utilizes a novel combination of the mesoscale phase-field method with atomistic approaches such as first-principles total energy and linear response calculations, as well as a mixed-space cluster expansion coupled with Monte Carlo simulations. We give quantitative first-principles predictions of: (i) bulk energetics of the Al-Cu solid solution and θ ' precipitate phases, (ii) interfacial energies of the coherent and semi-coherent θ ' /Al interfaces, and (iii) stress-free misfit strains and coherency strain energies of the θ ' /Al system. These first-principles data comprise all the necessary energetic information to construct our phase-field model of microstructural evolution. Using our multiscale approach, we elucidate the effects of various energetic contributions on the equilibrium shape of θ ' precipitates, finding that both the elastic energy and interfacial energy anisotropy contributions play critical roles in determining the aspect ratio of θ ' precipitates. Additionally, we have performed a quantitative study of the morphology of two-dimensional multi-precipitate microstructures during growth and coarsening, and compared the calculated results with experimentally observed morphologies. Our multiscale first-principles/phase-field method is completely general and should therefore be applicable to a wide variety of problems in microstructural evolution
Nuclear Hybrid Energy Systems FY16 Modeling Efforts at ORNL
Energy Technology Data Exchange (ETDEWEB)
Cetiner, Sacit M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guler Yigitoglu, Askin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2016-09-01
A nuclear hybrid system uses a nuclear reactor as the basic power generation unit. The power generated by the nuclear reactor is utilized by one or more power customers as either thermal power, electrical power, or both. In general, a nuclear hybrid system will couple the nuclear reactor to at least one thermal power user in addition to the power conversion system. The definition and architecture of a particular nuclear hybrid system is flexible depending on local markets needs and opportunities. For example, locations in need of potable water may be best served by coupling a desalination plant to the nuclear system. Similarly, an area near oil refineries may have a need for emission-free hydrogen production. A nuclear hybrid system expands the nuclear power plant from its more familiar central power station role by diversifying its immediately and directly connected customer base. The definition, design, analysis, and optimization work currently performed with respect to the nuclear hybrid systems represents the work of three national laboratories. Idaho National Laboratory (INL) is the lead lab working with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory. Each laboratory is providing modeling and simulation expertise for the integration of the hybrid system.
International Nuclear Information System (INIS)
Gomez, Elena; Calvar, Noelia; Dominguez, Angeles; Macedo, Eugenia A.
2011-01-01
Research highlights: → The osmotic coefficients of binary mixtures (alcohol + ionic liquid) were determined. → The measurements were carried out with a vapor pressure osmometer at 323.15 K. → The Pitzer-Archer, and the MNRTL models were used to correlate the experimental data. → Mean molal activity coefficients and excess Gibbs free energies were calculated. - Abstract: Measurement of osmotic coefficients of binary mixtures containing several primary and secondary alcohols (1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol) and the pyridinium-based ionic liquid 1,3-dimethylpyridinium methylsulfate were performed at T = 323.15 K using the vapor pressure osmometry technique, and from experimental data, vapor pressure, and activity coefficients were determined. The extended Pitzer model modified by Archer, and the NRTL model modified by Jaretun and Aly (MNRTL) were used to correlate the experimental osmotic coefficients, obtaining standard deviations lower than 0.017 and 0.054, respectively. From the parameters obtained with the extended Pitzer model modified by Archer, the mean molal activity coefficients and the excess Gibbs free energy for the studied binary mixtures were calculated. The effect of the cation is studied comparing the experimental results with those obtained for the ionic liquid 1,3-dimethylimidazolium methylsulfate.
The phase behavior of a hard sphere chain model of a binary n-alkane mixture
International Nuclear Information System (INIS)
Malanoski, A. P.; Monson, P. A.
2000-01-01
Monte Carlo computer simulations have been used to study the solid and fluid phase properties as well as phase equilibrium in a flexible, united atom, hard sphere chain model of n-heptane/n-octane mixtures. We describe a methodology for calculating the chemical potentials for the components in the mixture based on a technique used previously for atomic mixtures. The mixture was found to conform accurately to ideal solution behavior in the fluid phase. However, much greater nonidealities were seen in the solid phase. Phase equilibrium calculations indicate a phase diagram with solid-fluid phase equilibrium and a eutectic point. The components are only miscible in the solid phase for dilute solutions of the shorter chains in the longer chains. (c) 2000 American Institute of Physics
Concurrent algorithms for nuclear shell model calculations
International Nuclear Information System (INIS)
Mackenzie, L.M.; Macleod, A.M.; Berry, D.J.; Whitehead, R.R.
1988-01-01
The calculation of nuclear properties has proved very successful for light nuclei, but is limited by the power of the present generation of computers. Starting with an analysis of current techniques, this paper discusses how these can be modified to map parallelism inherent in the mathematics onto appropriate parallel machines. A prototype dedicated multiprocessor for nuclear structure calculations, designed and constructed by the authors, is described and evaluated. The approach adopted is discussed in the context of a number of generically similar algorithms. (orig.)
Light-front nuclear shell-model
International Nuclear Information System (INIS)
Johnson, M.B.
1990-01-01
I examine the effects of nuclear structure on high-energy, high-momentum transfer processes, specifically the EMC effect. For pedagogical reasons, a fictitious but simple two-body system consisting of two equal-mass particles interacting in a harmonic oscillator potential has been chosen. For this toy nucleus, I utilize a widely-used link between instant-form and light-front dynamics, formulating nuclear structure and deep-inelastic scattering consistently in the laboratory system. Binding effects are compared within conventional instant-form and light-front dynamical frameworks, with appreciable differences being found in the two cases. 20 refs
Power systems with nuclear-electric generators - Modelling methods
International Nuclear Information System (INIS)
Valeca, Serban Constantin
2002-01-01
This is a vast analysis on the issue of sustainable nuclear power development with direct conclusions regarding the Nuclear Programme of Romania. The work is targeting specialists and decision making boards. Specific to the nuclear power development is its public implication, the public being most often misinformed by non-professional media. The following problems are debated thoroughly: - safety, nuclear risk, respectively, is treated in chapter 1 and 7 aiming at highlighting the quality of nuclear power and consequently paving the way to public acceptance; - the environment considered both as resource of raw materials and medium essential for life continuation, which should be appropriately protected to ensure healthy and sustainable development of human society; its analysis is also presented in chapter 1 and 7, where the problem of safe management of radioactive waste is addressed too; - investigation methods based on information science of nuclear systems, applied in carrying out the nuclear strategy and planning are widely analyzed in the chapter 2, 3 and 6; - optimizing the processes by following up the structure of investment and operation costs, and, generally, the management of nuclear units is treated in the chapter 5 and 7; - nuclear weapon proliferation as a possible consequence of nuclear power generation is treated as a legal issue. The development of Romanian NPP at Cernavoda, practically, the core of the National Nuclear Programme, is described in chapter 8. Actually, the originality of the present work consists in the selection and adaptation from a multitude of mathematical models applicable to the local and specific conditions of nuclear power plant at Cernavoda. The Romanian economy development and power development oriented towards reduction of fossil fuel consumption and protection of environment, most reliably ensured by the nuclear power, is discussed in the frame of the world trends of the energy production. Various scenarios are
Operational characteristics of nuclear power plants - modelling of operational safety
International Nuclear Information System (INIS)
Studovic, M.
1984-01-01
By operational experience of nuclear power plants and realize dlevel of availability of plant, systems and componenst reliabiliuty, operational safety and public protection, as a source on nature of distrurbances in power plant systems and lessons drawn by the TMI-2, in th epaper are discussed: examination of design safety for ultimate ensuring of safe operational conditions of the nuclear power plant; significance of the adequate action for keeping proess parameters in prescribed limits and reactor cooling rquirements; developed systems for measurements detection and monitoring all critical parameters in the nuclear steam supply system; contents of theoretical investigation and mathematical modeling of the physical phenomena and process in nuclear power plant system and components as software, supporting for ensuring of operational safety and new access in staff education process; program and progress of the investigation of some physical phenomena and mathematical modeling of nuclear plant transients, prepared at faculty of mechanical Engineering in Belgrade. (author)
Seismic model of the nuclear boiler SPX2
International Nuclear Information System (INIS)
Christodoulou, K.
1982-01-01
A model of the nuclear boiler SPX2 is proposed in this paper enabling to carry out comparative calculations on the response to seismic effects. The calculations are made in CISE and SEPTEN departments of Electricite de France [fr
Ekki Syamsulhakim
2008-01-01
This paper aims to exercise a rather recent trend in applied microeconometrics, namely the effect of sampling design on statistical inference, especially on binary outcome model. Many theoretical research in econometrics have shown the inappropriateness of applying i.i.dassumed statistical analysis on non-i.i.d data. These research have provided proofs showing that applying the iid-assumed analysis on a non-iid observations would result in an inflated standard errors which could make the esti...
Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems
International Nuclear Information System (INIS)
Svoboda, J; Fischer, F D
2014-01-01
Abnormal grain growth as the abrupt growth of a group of the largest grains in a multi-grain system is treated within the context of unequal retardation of grain growth due to the segregation of solute atoms from the bulk of the grains into the grain boundaries. During grain boundary migration, the segregated solute atoms are dragged under a small driving force or left behind the migrating grain boundary under a large driving force. Thus, the solute atoms in the grain boundaries of large grains, exhibiting a large driving force, can be released from the grain boundary. The mobility of these grain boundaries becomes significantly higher and abnormal grain growth is spontaneously provoked. The mean-field model presented here assumes that each grain is described by its grain radius and by its individual segregation parameter. The thermodynamic extremal principle is engaged to obtain explicit evolution equations for the radius and segregation parameter of each grain. Simulations of grain growth kinetics for various conditions of segregation with the same initial setting (100 000 grains with a given radius distribution) are presented. Depending on the diffusion coefficients of the solute in the grain boundaries, abnormal grain growth may be strongly or marginally pronounced. Solute segregation and drag can also significantly contribute to the stabilization of the grain structure. Qualitative agreement with several experimental results is reported. (paper)
Liu, Michael C.; Dupuy, Trent J.; Leggett, S. K.
2010-10-01
Highly unequal-mass ratio binaries are rare among field brown dwarfs, with the mass ratio distribution of the known census described by q (4.9±0.7). However, such systems enable a unique test of the joint accuracy of evolutionary and atmospheric models, under the constraint of coevality for the individual components (the "isochrone test"). We carry out this test using two of the most extreme field substellar binaries currently known, the T1 + T6 epsilon Ind Bab binary and a newly discovered 0farcs14 T2.0 + T7.5 binary, 2MASS J12095613-1004008AB, identified with Keck laser guide star adaptive optics. The latter is the most extreme tight binary resolved to date (q ≈ 0.5). Based on the locations of the binary components on the Hertzsprung-Russell (H-R) diagram, current models successfully indicate that these two systems are coeval, with internal age differences of log(age) = -0.8 ± 1.3(-1.0+1.2 -1.3) dex and 0.5+0.4 -0.3(0.3+0.3 -0.4) dex for 2MASS J1209-1004AB and epsilon Ind Bab, respectively, as inferred from the Lyon (Tucson) models. However, the total mass of epsilon Ind Bab derived from the H-R diagram (≈ 80 M Jup using the Lyon models) is strongly discrepant with the reported dynamical mass. This problem, which is independent of the assumed age of the epsilon Ind Bab system, can be explained by a ≈ 50-100 K systematic error in the model atmosphere fitting, indicating slightly warmer temperatures for both components; bringing the mass determinations from the H-R diagram and the visual orbit into consistency leads to an inferred age of ≈ 6 Gyr for epsilon Ind Bab, older than previously assumed. Overall, the two T dwarf binaries studied here, along with recent results from T dwarfs in age and mass benchmark systems, yield evidence for small (≈100 K) errors in the evolutionary models and/or model atmospheres, but not significantly larger. Future parallax, resolved spectroscopy, and dynamical mass measurements for 2MASS J1209-1004AB will enable a more
International Nuclear Information System (INIS)
Adachi, T; Tanaka, S; Tazaki, M; Akiba, M; Takashima, R; Kuno, Y
2011-01-01
To construct suitable models for a reliable and sustainable international/regional framework in the fields of nuclear fuel cycle, it is essential to reflect recent political situations including such that 1) a certain number of emerging countries especially in south-east Asia want to introduce and develop nuclear power in the long-terms despite the accident of the Fukushima Daiichi NPP, and 2) exposition of nuclear proliferation threats provided by North Korea and Iran. It is also to be considered that Japan is an unique country having enrichment and reprocessing facilities on commercial base among non-nuclear weapon countries. Although many models presented for the internationalization have not been realized yet, studies at the University of Tokyo aim at multilateral nuclear approach (MNA) in Asian-Pacific countries balancing between nuclear non-proliferation and nuclear fuel supply/service and presenting specific examples such as prerequisites for participating countries, scope of cooperative activities, ownership of facilities and type of agreements/frameworks. We will present a model basic agreement and several bilateral and multi-lateral agreements for the combinations of industry or government led consortia including Japan and its neighboring countries and made a preliminary evaluation for the combination of processes/facilities based on the INFCIRC/640 report for MNA. (author)
Analytical solution of dispersion relations for the nuclear optical model
Energy Technology Data Exchange (ETDEWEB)
VanderKam, J.M. [Center for Communications Research, Thanet Road, Princeton, NJ 08540 (United States); Weisel, G.J. [Triangle Universities Nuclear Laboratory, and Duke University, Box 90308, Durham, NC 27708-0308 (United States); Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601-3760 (United States); Tornow, W. [Triangle Universities Nuclear Laboratory, and Duke University, Box 90308, Durham, NC 27708-0308 (United States)
2000-12-01
Analytical solutions of dispersion integral relations, linking the real and imaginary parts of the nuclear optical model, have been derived. These are displayed for some widely used forms of the volume- and surface-absorptive nuclear potentials. When the analytical solutions are incorporated into the optical-model search code GENOA, replacing a numerical integration, the code runs three and a half to seven times faster, greatly aiding the analysis of direct-reaction, elastic scattering data. (author)
Mayaud, C; Wagner, T; Benischke, R; Birk, S
2014-04-16
The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the
Energy Technology Data Exchange (ETDEWEB)
Das, N., E-mail: nirupamd@barc.gov.in [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Mittra, J. [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Murty, B.S. [Department of Metallurgical and Materials Engineering, IIT Madras, Chennai 600 036 (India); Pabi, S.K. [Department of Metallurgical and Materials Engineering, IIT Kharagpur, Kharagpur 721 302 (India); Kulkarni, U.D.; Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2013-02-15
Highlights: Black-Right-Pointing-Pointer A methodology was proposed to predict amorphous forming compositions (AFCs). Black-Right-Pointing-Pointer Chemical contribution to enthalpy of mixing {proportional_to} enthalpy of amorphous for AFCs. Black-Right-Pointing-Pointer Accuracy in the prediction of AFC-range was noticed in Al-Ni-Ti system. Black-Right-Pointing-Pointer Mechanical alloying (MA) results of Al-Ni-Ti followed the predicted AFC-range. Black-Right-Pointing-Pointer Earlier MA results of Al-Ni-Ti also conformed to the predicted AFC-range. - Abstract: From the earlier works on the prediction of amorphous forming composition range (AFCR) using Miedema based model and also, on mechanical alloying experiments it has been observed that all amorphous forming compositions of a given alloy system falls within a linear band when the chemical contribution to enthalpy of the solid solution ({Delta}H{sup ss}) is plotted against the enthalpy of mixing in the amorphous phase ({Delta}H{sup amor}). On the basis of this observation, a methodology has been proposed in this article to identify the AFCR of a ternary system that is likely to be more precise than what can be obtained using {Delta}H{sup amor} - {Delta}H{sup ss} < 0 criterion. MA experiments on various compositions of Al-Ni-Ti system, producing amorphous, crystalline, and mixture of amorphous plus crystalline phases have been carried out and the phases have been characterized using X-ray diffraction and transmission electron microscopy techniques. Data from the present MA experiments and, also, from the literature have been used to validate the proposed approach. Also, the proximity of compositions, producing a mixture of amorphous and crystalline phases to the boundary of AFCR in the Al-Ni-Ti ternary has been found useful to validate the effectiveness of the prediction.
Fire models for assessment of nuclear power plant fires
International Nuclear Information System (INIS)
Nicolette, V.F.; Nowlen, S.P.
1989-01-01
This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plants fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. 17 refs., 6 figs
Evaluating nuclear physics inputs in core-collapse supernova models
Lentz, E.; Hix, W. R.; Baird, M. L.; Messer, O. E. B.; Mezzacappa, A.
Core-collapse supernova models depend on the details of the nuclear and weak interaction physics inputs just as they depend on the details of the macroscopic physics (transport, hydrodynamics, etc.), numerical methods, and progenitors. We present preliminary results from our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions.
International Nuclear Information System (INIS)
Mahaki, Hanie; Memarpoor-Yazdi, Mina; Chamani, Jamshidkhan; Reza Saberi, Mohammad
2013-01-01
The aim of the present study was to describe the competition of ropinirole hydrochloride (RP) and aspirin (ASA) in binding to human serum albumin (HSA) in physiological buffer (pH=7.4) using multi-spectroscopic, molecular modeling and zeta-potential measurements. Fluorescence analysis was used to define the binding and quenching properties of drug-HSA complexes in binary and ternary systems. Fluorescence spectroscopy showed that in the presence of RP, the binding constant of HSA–ASA was increased. Static quenching was confirmed to result in the fluorescence quenching and FRET. The effect of drugs on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy, three-dimensional fluorescence spectra and circular dichroism (CD). The RLS method determined the critical aggregation concentration of drugs on HSA in binary and ternary systems that confirmed the zeta potential results. Structural modeling showed that the affinity of each of the drugs to HSA in binary and ternary systems confirms the spectroscopic results. - Highlights: ► We studied the interaction of ropinirole hydrochloride and aspirin with HSA. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We determined the critical induced aggregation concentration of both drugs on HSA. ► The binding mechanism of drugs as separate and simultaneous to HSA has been compared. ► The binding site of both drugs as simultaneous effects on HSA has been determined.
Energy Technology Data Exchange (ETDEWEB)
Mahaki, Hanie, E-mail: hanieh.mahaki@gmail.com [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Memarpoor-Yazdi, Mina; Chamani, Jamshidkhan [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Reza Saberi, Mohammad [Medical Chemistry Department, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)
2013-02-15
The aim of the present study was to describe the competition of ropinirole hydrochloride (RP) and aspirin (ASA) in binding to human serum albumin (HSA) in physiological buffer (pH=7.4) using multi-spectroscopic, molecular modeling and zeta-potential measurements. Fluorescence analysis was used to define the binding and quenching properties of drug-HSA complexes in binary and ternary systems. Fluorescence spectroscopy showed that in the presence of RP, the binding constant of HSA-ASA was increased. Static quenching was confirmed to result in the fluorescence quenching and FRET. The effect of drugs on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy, three-dimensional fluorescence spectra and circular dichroism (CD). The RLS method determined the critical aggregation concentration of drugs on HSA in binary and ternary systems that confirmed the zeta potential results. Structural modeling showed that the affinity of each of the drugs to HSA in binary and ternary systems confirms the spectroscopic results. - Highlights: Black-Right-Pointing-Pointer We studied the interaction of ropinirole hydrochloride and aspirin with HSA. Black-Right-Pointing-Pointer Molecular modeling and zeta-potential used to describe competitive interaction. Black-Right-Pointing-Pointer We determined the critical induced aggregation concentration of both drugs on HSA. Black-Right-Pointing-Pointer The binding mechanism of drugs as separate and simultaneous to HSA has been compared. Black-Right-Pointing-Pointer The binding site of both drugs as simultaneous effects on HSA has been determined.
Physical Structure of Four Symbiotic Binaries
Kenyon, Scott J. (Principal Investigator)
1997-01-01
Disk accretion powers many astronomical objects, including pre-main sequence stars, interacting binary systems, and active galactic nuclei. Unfortunately, models developed to explain the behavior of disks and their surroundings - boundary layers, jets, and winds - lack much predictive power, because the physical mechanism driving disk evolution - the viscosity - is not understood. Observations of many types of accreting systems are needed to constrain the basic physics of disks and provide input for improved models. Symbiotic stars are an attractive laboratory for studying physical phenomena associated with disk accretion. These long period binaries (P(sub orb) approx. 2-3 yr) contain an evolved red giant star, a hot companion, and an ionized nebula. The secondary star usually is a white dwarf accreting material from the wind of its red giant companion. A good example of this type of symbiotic is BF Cygni: our analysis shows that disk accretion powers the nuclear burning shell of the hot white dwarf and also manages to eject material perpendicular to the orbital plane (Mikolajewska, Kenyon, and Mikolajewski 1989). The hot components in other symbiotic binaries appear powered by tidal overflow from a very evolved red giant companion. We recently completed a study of CI Cygni and demonstrated that the accreting secondary is a solar-type main sequence star, rather than a white dwarf (Kenyon et aL 1991). This project continued our study of symbiotic binary systems. Our general plan was to combine archival ultraviolet and optical spectrophotometry with high quality optical radial velocity observations to determine the variation of line and continuum sources as functions of orbital phase. We were very successful in generating orbital solutions and phasing UV+optical spectra for five systems: AG Dra, V443 Her, RW Hya, AG Peg, and AX Per. Summaries of our main results for these systems appear below. A second goal of our project was to consider general models for the
Solving the nuclear shell model with an algebraic method
International Nuclear Information System (INIS)
Feng, D.H.; Pan, X.W.; Guidry, M.
1997-01-01
We illustrate algebraic methods in the nuclear shell model through a concrete example, the fermion dynamical symmetry model (FDSM). We use this model to introduce important concepts such as dynamical symmetry, symmetry breaking, effective symmetry, and diagonalization within a higher-symmetry basis. (orig.)
The string model of nuclear scattering: an introduction
International Nuclear Information System (INIS)
Werner, Klaus
1995-01-01
We discuss the string model of hadronic and nuclear scattering at ultrarelativistic energies. The man purpose is to treat theoretical concepts common to essentially all successful models: strings, Pomerons, and their marriage int he string model approach. We stay an introductory level without going into technical details. (author)
International Nuclear Information System (INIS)
Xie, Yong; Shi, Hongwei; Du, Cunbin; Cong, Yang; Wang, Jian; Zhao, Hongkun
2016-01-01
Highlights: • Solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents were determined. • Solubility data were correlated and calculated by five models. • The standard molar enthalpy for the dissolution processes were calculated. - Abstract: The solubility of 3-chloro-N-phenylphthalimide in binary mixed solvents of (acetone + methanol, ethyl acetate + methanol and 1,4-dioxane + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (288.15 to 323.15) K under atmosphere pressure. For the binary systems of (acetone + methanol) and (1,4-dioxane + methanol), the solubility of 3-chloro-N-phenylphthalimide increased with increasing temperature and mass fraction of acetone or 1,4-dioxane; and for the (ethyl acetate + methanol) system, at a given composition of ethyl acetate, the solubility of 3-chloro-N-phenylphthalimide increased with an increase in temperature; nevertheless at the same temperature, they increased at first and then decreased with increasing mass fraction of 1,4-dioxane. At the same temperature and mass fraction of acetone, ethyl acetate or 1,4-dioxane, the solubility of 3-chloro-N-phenylphthalimide was greater in (1,4-dioxane + methanol) than in the other two mixed solvents. The solubility values were correlated by employing the Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, Apelblat–Jouyban–Acree model, Ma model, and Sun model. On the whole, the Ma model and Sun model were proven to provide good representation of the experimental solubility results. Furthermore, the dissolution enthalpies of the dissolution process were calculated. The dissolution process of 3-chloro-N-phenylphthalimide in these mixed solvents is endothermic. The experimental solubility and the models in this study could be helpful in purifying 3-chloro-N-phenylphthalimide.
Monte Carlo Numerical Models for Nuclear Logging Applications
Directory of Open Access Journals (Sweden)
Fusheng Li
2012-06-01
Full Text Available Nuclear logging is one of most important logging services provided by many oil service companies. The main parameters of interest are formation porosity, bulk density, and natural radiation. Other services are also provided from using complex nuclear logging tools, such as formation lithology/mineralogy, etc. Some parameters can be measured by using neutron logging tools and some can only be measured by using a gamma ray tool. To understand the response of nuclear logging tools, the neutron transport/diffusion theory and photon diffusion theory are needed. Unfortunately, for most cases there are no analytical answers if complex tool geometry is involved. For many years, Monte Carlo numerical models have been used by nuclear scientists in the well logging industry to address these challenges. The models have been widely employed in the optimization of nuclear logging tool design, and the development of interpretation methods for nuclear logs. They have also been used to predict the response of nuclear logging systems for forward simulation problems. In this case, the system parameters including geometry, materials and nuclear sources, etc., are pre-defined and the transportation and interactions of nuclear particles (such as neutrons, photons and/or electrons in the regions of interest are simulated according to detailed nuclear physics theory and their nuclear cross-section data (probability of interacting. Then the deposited energies of particles entering the detectors are recorded and tallied and the tool responses to such a scenario are generated. A general-purpose code named Monte Carlo N– Particle (MCNP has been the industry-standard for some time. In this paper, we briefly introduce the fundamental principles of Monte Carlo numerical modeling and review the physics of MCNP. Some of the latest developments of Monte Carlo Models are also reviewed. A variety of examples are presented to illustrate the uses of Monte Carlo numerical models
Nuclear Hybrid Energy System Model Stability Testing
Energy Technology Data Exchange (ETDEWEB)
Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cetiner, Sacit M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2017-04-01
A Nuclear Hybrid Energy System (NHES) uses a nuclear reactor as the basic power generation unit, and the power generated is used by multiple customers as combinations of thermal power or electrical power. The definition and architecture of a particular NHES can be adapted based on the needs and opportunities of different localities and markets. For example, locations in need of potable water may be best served by coupling a desalination plant to the NHES. Similarly, a location near oil refineries may have a need for emission-free hydrogen production. Using the flexible, multi-domain capabilities of Modelica, Argonne National Laboratory, Idaho National Laboratory, and Oak Ridge National Laboratory are investigating the dynamics (e.g., thermal hydraulics and electrical generation/consumption) and cost of a hybrid system. This paper examines the NHES work underway, emphasizing the control system developed for individual subsystems and the overall supervisory control system.
Modified quark-meson coupling model for nuclear matter
International Nuclear Information System (INIS)
Jin, X.; Jennings, B.K.
1996-01-01
The quark-meson coupling model for nuclear matter, which describes nuclear matter as nonoverlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons, is modified by introducing medium modification of the bag constant. We model the density dependence of the bag constant in two different ways: One invokes a direct coupling of the bag constant to the scalar meson field, and the other relates the bag constant to the in-medium nucleon mass. Both models feature a decreasing bag constant with increasing density. We find that when the bag constant is significantly reduced in nuclear medium with respect to its free-space value, large canceling isoscalar Lorentz scalar and vector potentials for the nucleon in nuclear matter emerge naturally. Such potentials are comparable to those suggested by relativistic nuclear phenomenology and finite-density QCD sum rules. This suggests that the reduction of bag constant in nuclear medium may play an important role in low- and medium-energy nuclear physics. copyright 1996 The American Physical Society
Infrastructure development assistance modeling for nuclear power plant
International Nuclear Information System (INIS)
Park, J. H.; Hwang, K.; Park, K. M.; Kim, S. W.; Lee, S. M.
2012-01-01
The purpose of this paper is to develop a model, a general frame to be utilized in assisting newcomer countries to start a nuclear power program. A nuclear power plant project involves technical complexity and high level of investment with long duration. Considering newcomers are mostly developing countries that lack the national infrastructure, key infrastructure issues may constitute the principal constraints to the development of a nuclear power program. In this regard, it is important to provide guidance and support to set up an appropriate infrastructure when we help them with the first launch of nuclear power plant project. To date, as a sole nuclear power generation company, KHNP has been invited many times to mentor or assist newcomer countries for their successful start of a nuclear power program since Republic of Korea is an exemplary case of a developing country which began nuclear power program from scratch and became a major world nuclear energy country in a short period of time. Through hosting events organized to aid newcomer countries' initiation of nuclear power projects, difficulties have been recognized. Each event had different contents according to circumstances because they were held as an unstructured and one-off thing. By developing a general model, we can give more adequate and effective aid in an efficient way. In this paper, we created a model to identify necessary infrastructures at the right stage, which was mainly based on a case of Korea. Taking into account the assistance we received from foreign companies and our own efforts for technological self-reliance, we have developed a general time table and specified activities required to do at each stage. From a donor's perspective, we explored various ways to help nuclear infrastructure development including technical support programs, training courses, and participating in IAEA technical cooperation programs on a regular basis. If we further develop the model, the next task would be to
Infrastructure development assistance modeling for nuclear power plant
Energy Technology Data Exchange (ETDEWEB)
Park, J. H.; Hwang, K.; Park, K. M.; Kim, S. W.; Lee, S. M. [Korea Hydro and Nuclear Power Co., LTD, 23, 106 gil, Yeongdong-daero, Gangnam-gu, 153-791 (Korea, Republic of)
2012-07-01
The purpose of this paper is to develop a model, a general frame to be utilized in assisting newcomer countries to start a nuclear power program. A nuclear power plant project involves technical complexity and high level of investment with long duration. Considering newcomers are mostly developing countries that lack the national infrastructure, key infrastructure issues may constitute the principal constraints to the development of a nuclear power program. In this regard, it is important to provide guidance and support to set up an appropriate infrastructure when we help them with the first launch of nuclear power plant project. To date, as a sole nuclear power generation company, KHNP has been invited many times to mentor or assist newcomer countries for their successful start of a nuclear power program since Republic of Korea is an exemplary case of a developing country which began nuclear power program from scratch and became a major world nuclear energy country in a short period of time. Through hosting events organized to aid newcomer countries' initiation of nuclear power projects, difficulties have been recognized. Each event had different contents according to circumstances because they were held as an unstructured and one-off thing. By developing a general model, we can give more adequate and effective aid in an efficient way. In this paper, we created a model to identify necessary infrastructures at the right stage, which was mainly based on a case of Korea. Taking into account the assistance we received from foreign companies and our own efforts for technological self-reliance, we have developed a general time table and specified activities required to do at each stage. From a donor's perspective, we explored various ways to help nuclear infrastructure development including technical support programs, training courses, and participating in IAEA technical cooperation programs on a regular basis. If we further develop the model, the next task
Binary neutron star merger simulations
Energy Technology Data Exchange (ETDEWEB)
Bruegmann, Bernd [Jena Univ. (Germany)
2016-11-01
Our research focuses on the numerical tools necessary to solve Einstein's equations. In recent years we have been particularly interested in spacetimes consisting of two neutron stars in the final stages of their evolution. Because of the emission of gravitational radiation, the objects are driven together to merge; the emitted gravitational wave signal is visualized. This emitted gravitational radiation carries energy and momentum away from the system and contains information about the system. Late last year the Laser Interferometer Gravitational-wave Observatory (LIGO) began searches for these gravitational wave signals at a sensitivity at which detections are expected. Although such systems can radiate a significant amount of their total mass-energy in gravitational waves, the gravitational wave signals one expects to receive on Earth are not strong, since sources of gravitational waves are often many millions of light years away. Therefore one needs accurate templates for the radiation one expects from such systems in order to be able to extract them out of the detector's noise. Although analytical models exist for compact binary systems when the constituents are well separated, we need numerical simulation to investigate the last orbits before merger to obtain accurate templates and validate analytical approximations. Due to the strong nonlinearity of the equations and the large separation of length scales, these simulations are computationally demanding and need to be run on large supercomputers. When matter is present the computational cost as compared to pure black hole (vacuum) simulations increases even more due to the additional matter fields. But also more interesting astrophysical phenomena can happen. In fact, there is the possibility for a strong electromagnetic signal from the merger (e.g., a short gamma-ray burst or lower-energy electromagnetic signatures from the ejecta) and significant neutrino emission. Additionally, we can expect that
Directory of Open Access Journals (Sweden)
Paccaud Fred
2004-04-01
Full Text Available Abstract Background We sought to improve upon previously published statistical modeling strategies for binary classification of dyslipidemia for general population screening purposes based on the waist-to-hip circumference ratio and body mass index anthropometric measurements. Methods Study subjects were participants in WHO-MONICA population-based surveys conducted in two Swiss regions. Outcome variables were based on the total serum cholesterol to high density lipoprotein cholesterol ratio. The other potential predictor variables were gender, age, current cigarette smoking, and hypertension. The models investigated were: (i linear regression; (ii logistic classification; (iii regression trees; (iv classification trees (iii and iv are collectively known as "CART". Binary classification performance of the region-specific models was externally validated by classifying the subjects from the other region. Results Waist-to-hip circumference ratio and body mass index remained modest predictors of dyslipidemia. Correct classification rates for all models were 60–80%, with marked gender differences. Gender-specific models provided only small gains in classification. The external validations provided assurance about the stability of the models. Conclusions There were no striking differences between either the algebraic (i, ii vs. non-algebraic (iii, iv, or the regression (i, iii vs. classification (ii, iv modeling approaches. Anticipated advantages of the CART vs. simple additive linear and logistic models were less than expected in this particular application with a relatively small set of predictor variables. CART models may be more useful when considering main effects and interactions between larger sets of predictor variables.
Testing the predictive power of nuclear mass models
International Nuclear Information System (INIS)
Mendoza-Temis, J.; Morales, I.; Barea, J.; Frank, A.; Hirsch, J.G.; Vieyra, J.C. Lopez; Van Isacker, P.; Velazquez, V.
2008-01-01
A number of tests are introduced which probe the ability of nuclear mass models to extrapolate. Three models are analyzed in detail: the liquid drop model, the liquid drop model plus empirical shell corrections and the Duflo-Zuker mass formula. If predicted nuclei are close to the fitted ones, average errors in predicted and fitted masses are similar. However, the challenge of predicting nuclear masses in a region stabilized by shell effects (e.g., the lead region) is far more difficult. The Duflo-Zuker mass formula emerges as a powerful predictive tool
Development of real options model for nuclear power plants
International Nuclear Information System (INIS)
Ono, Kenji
2004-01-01
As the Japanese electricity market is deregulated, it becomes more important for electric utilities to recognize their financial risks and to adopt strategic and scientific decision making methodology. We have developed two models for valuation of Japanese nuclear power plants to support utilities' decision making. One is a net present value (NPV) model using discounted cash flow analysis method. Another is a real options model. This model is based on strict financial technology theory and can calculate value of early retirement, life extension and new unit addition options of nuclear units under electricity price uncertainty. This can also derive an optimal period for retirement, life extension and new unit addition. (author)
Siers, Shane R.; Reed, Robert N.; Savidge, Julie A.
2016-01-01
Roads are significant barriers to landscape-scale movements of individuals or populations of many wildlife taxa. The decision by an animal near a road to either cross or not cross may be influenced by characteristics of the road, environmental conditions, traits of the individual animal, and other aspects of the context within which the decision is made. We considered such factors in a mixed-effects logistic regression model describing the nightly road crossing probabilities of invasive nocturnal Brown Treesnakes (Boiga irregularis) through short-term radiotracking of 691 snakes within close proximity to 50 road segments across the island of Guam. All measures of road magnitude (traffic volume, gap width, surface type, etc.) were significantly negatively correlated with crossing probabilities. Snake body size was the only intrinsic factor associated with crossing rates, with larger snakes crossing roads more frequently. Humidity was the only environmental variable affecting crossing rate. The distance of the snake from the road at the start of nightly movement trials was the most significant predictor of crossings. The presence of snake traps with live mouse lures during a portion of the trials indicated that localized prey cues reduced the probability of a snake crossing the road away from the traps, suggesting that a snake's decision to cross roads is influenced by local foraging opportunities. Per capita road crossing rates of Brown Treesnakes were very low, and comparisons to historical records suggest that crossing rates have declined in the 60+ yr since introduction to Guam. We report a simplified model that will allow managers to predict road crossing rates based on snake, road, and contextual characteristics. Road crossing simulations based on actual snake size distributions demonstrate that populations with size distributions skewed toward larger snakes will result in a higher number of road crossings. Our method of modeling per capita road crossing
Modeling the degradation of nuclear components
International Nuclear Information System (INIS)
Stock, D.; Samanta, P.; Vesely, W.
1993-01-01
This paper describes component level reliability models that use information on degradation to predict component reliability, and which have been used to evaluate different maintenance and testing policies. The models are based on continuous time Markov processes, and are a generalization of reliability models currently used in Probabilistic Risk Assessment. An explanation of the models, the model parameters, and an example of how these models can be used to evaluate maintenance policies are discussed
Identification of a nuclear plant dynamics via ARMAX model
International Nuclear Information System (INIS)
Yamamoto, Shigeki; Otsuji, Tomoo; Muramatsu, Eiichi
2000-01-01
Dynamics of the reactor of nuclear ship 'Mutsu' is described by a linear time-invariant discrete-time model which is referred to as ARMAX (Auto-Regressive Moving Average eXogenious inputs) model. Applying system identification methods, parameters of the ARMAX model are determined from input-output data of the reactor. Accuracy of the model is examined in time and frequency domain. We show that the model can be a good approximation of the plant dynamics. (author)
Czech Academy of Sciences Publication Activity Database
Chadima, P.; Fiřt, R.; Harmanec, P.; Wolf, M.; Ruždjak, D.; Božić, H.; Koubský, Pavel
2011-01-01
Roč. 142, č. 1 (2011), 7/1-7/4 ISSN 0004-6256 Institutional research plan: CEZ:AV0Z10030501 Keywords : close binaries stars * circumstellar matter * emission-line Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.035, year: 2011
Large scale Bayesian nuclear data evaluation with consistent model defects
International Nuclear Information System (INIS)
Schnabel, G
2015-01-01
The aim of nuclear data evaluation is the reliable determination of cross sections and related quantities of the atomic nuclei. To this end, evaluation methods are applied which combine the information of experiments with the results of model calculations. The evaluated observables with their associated uncertainties and correlations are assembled into data sets, which are required for the development of novel nuclear facilities, such as fusion reactors for energy supply, and accelerator driven systems for nuclear waste incineration. The efficiency and safety of such future facilities is dependent on the quality of these data sets and thus also on the reliability of the applied evaluation methods. This work investigated the performance of the majority of available evaluation methods in two scenarios. The study indicated the importance of an essential component in these methods, which is the frequently ignored deficiency of nuclear models. Usually, nuclear models are based on approximations and thus their predictions may deviate from reliable experimental data. As demonstrated in this thesis, the neglect of this possibility in evaluation methods can lead to estimates of observables which are inconsistent with experimental data. Due to this finding, an extension of Bayesian evaluation methods is proposed to take into account the deficiency of the nuclear models. The deficiency is modeled as a random function in terms of a Gaussian process and combined with the model prediction. This novel formulation conserves sum rules and allows to explicitly estimate the magnitude of model deficiency. Both features are missing in available evaluation methods so far. Furthermore, two improvements of existing methods have been developed in the course of this thesis. The first improvement concerns methods relying on Monte Carlo sampling. A Metropolis-Hastings scheme with a specific proposal distribution is suggested, which proved to be more efficient in the studied scenarios than the
A probabilistic model for US nuclear power construction times
International Nuclear Information System (INIS)
Shash, A.A.H.
1988-01-01
Construction time for nuclear power plants is an important element in planning for resources to meet future load demands. Analysis of actual versus estimated construction times for past US nuclear power plants indicates that utilities have continuously underestimated their power plants' construction durations. The analysis also indicates that the actual average construction time has been increasing upward, and the actual durations of power plants permitted to construct in the same year varied substantially. This study presents two probabilistic models for nuclear power construction time for use by the nuclear industry as estimating tool. The study also presents a detailed explanation of the factors that are responsible for increasing and varying nuclear power construction times. Observations on 91 complete nuclear units were involved in three interdependent analyses in the process of explanation and derivation of the probabilistic models. The historical data was first utilized in the data envelopment analysis (DEA) for the purpose of obtaining frontier index measures for project management achievement in building nuclear power plants
A New Dynamic Model for Nuclear Fuel Cycle System Analysis
International Nuclear Information System (INIS)
Choi, Sungyeol; Ko, Won Il
2014-01-01
The evaluation of mass flow is a complex process where numerous parameters and their complex interaction are involved. Given that many nuclear power countries have light and heavy water reactors and associated fuel cycle technologies, the mass flow analysis has to consider a dynamic transition from the open fuel cycle to other cycles over decades or a century. Although an equilibrium analysis provides insight concerning the end-states of fuel cycle transitions, it cannot answer when we need specific management options, whether the current plan can deliver these options when needed, and how fast the equilibrium can be achieved. As a pilot application, the government brought several experts together to conduct preliminary evaluations for nuclear fuel cycle options in 2010. According to Table 1, they concluded that the closed nuclear fuel cycle has long-term advantages over the open fuel cycle. However, it is still necessary to assess these options in depth and to optimize transition paths of these long-term options with advanced dynamic fuel cycle models. A dynamic simulation model for nuclear fuel cycle systems was developed and its dynamic mass flow analysis capability was validated against the results of existing models. This model can reflects a complex combination of various fuel cycle processes and reactor types, from once-through to multiple recycling, within a single nuclear fuel cycle system. For the open fuel cycle, the results of the developed model are well matched with the results of other models
Thermohydraulic tests in nuclear fuel model
International Nuclear Information System (INIS)
Ladeira, L.C.D.; Navarro, M.A.
1984-01-01
The main experimental works performed in the Thermohydraulics Laboratory of the NUCLEBRAS Nuclear Technology Development Center, in the field of thermofluodynamics are briefly described. These works include the performing of steady-state flow tests in single tube test sections, and the design and construction of a rod bundle test section, which will be also used for those kind of testes. Mention is made of the works to be performed in the near future, related to steady-state and transient flow tests. (Author) [pt
Models of high energy nuclear collisions
International Nuclear Information System (INIS)
Glendenning, N.K.
1978-06-01
The discussion covers nuclear collisions at relativistic energies including classes of high energy nucleus--nucleus collisions, and the kinetics of a central collision; and the asymptotic hadron spectrum including known and unknown hadrons, the relevance of the spectrum and the means of its study, thermodynamics of hadronic matter, examples of hadronic spectra, the temperature, composition of the initial fireball and its expansion, isoergic expansion with no pre-freezeout radiation, isentropic expansion of the fireball, the quasi-dynamical expansion, and finally antinuclei, hypernuclei, and the quark phase. 28 references
Modeling of the core of Atucha II nuclear power plant
International Nuclear Information System (INIS)
Blanco, Anibal
2007-01-01
This work is part of a Nuclear Engineer degree thesis of the Instituto Balseiro and it is carried out under the development of an Argentinean Nuclear Power Plant Simulator. To obtain the best representation of the reactor physical behavior using the state of the art tools this Simulator should couple a 3D neutronics core calculation code with a thermal-hydraulics system code. Focused in the neutronic nature of this job, using PARCS, we modeled and performed calculations of the nuclear power plant Atucha 2 core. Whenever it is possible, we compare our results against results obtained with PUMA (the official core code for Atucha 2). (author) [es
Methodology and preliminary models for analyzing nuclear-safeguards decisions
International Nuclear Information System (INIS)
Judd, B.R.; Weissenberger, S.
1978-11-01
This report describes a general analytical tool designed with Lawrence Livermore Laboratory to assist the Nuclear Regulatory Commission in making nuclear safeguards decisions. The approach is based on decision analysis - a quantitative procedure for making decisions under uncertain conditions. The report: describes illustrative models that quantify the probability and consequences of diverted special nuclear material and the costs of safeguarding the material; demonstrates a methodology for using this information to set safeguards regulations (safeguards criteria); and summarizes insights gained in a very preliminary assessment of a hypothetical reprocessing plant
Choiri, S.; Ainurofiq, A.
2018-03-01
Drug release from a montmorillonite (MMT) matrix is a complex mechanism controlled by swelling mechanism of MMT and an interaction of drug and MMT. The aim of this research was to explain a suitable model of the drug release mechanism from MMT and its binary mixture with a hydrophilic polymer in the controlled release formulation based on a compartmental modelling approach. Theophylline was used as a drug model and incorporated into MMT and a binary mixture with hydroxyl propyl methyl cellulose (HPMC) as a hydrophilic polymer, by a kneading method. The dissolution test was performed and the modelling of drug release was assisted by a WinSAAM software. A 2 model was purposed based on the swelling capability and basal spacing of MMT compartments. The model evaluation was carried out to goodness of fit and statistical parameters and models were validated by a cross-validation technique. The drug release from MMT matrix regulated by a burst release mechanism of unloaded drug, swelling ability, basal spacing of MMT compartment, and equilibrium between basal spacing and swelling compartments. Furthermore, the addition of HPMC in MMT system altered the presence of swelling compartment and equilibrium between swelling and basal spacing compartment systems. In addition, a hydrophilic polymer reduced the burst release mechanism of unloaded drug.
International Nuclear Information System (INIS)
Rudzok, S.; Schlink, U.; Herbarth, O.; Bauer, M.
2010-01-01
The interaction of drugs and non-therapeutic xenobiotics constitutes a central role in human health risk assessment. Still, available data are rare. Two different models have been established to predict mixture toxicity from single dose data, namely, the concentration addition (CA) and independent action (IA) model. However, chemicals can also act synergistic or antagonistic or in dose level deviation, or in a dose ratio dependent deviation. In the present study we used the MIXTOX model (EU project ENV4-CT97-0507), which incorporates these algorithms, to assess effects of the binary mixtures in the human hepatoma cell line HepG2. These cells possess a liver-like enzyme pattern and a variety of xenobiotic-metabolizing enzymes (phases I and II). We tested binary mixtures of the metal nickel, the anti-inflammatory drug diclofenac, and the antibiotic agent irgasan and compared the experimental data to the mathematical models. Cell viability was determined by three different methods the MTT-, AlamarBlue (registered) and NRU assay. The compounds were tested separately and in combinations. We could show that the metal nickel is the dominant component in the mixture, affecting an antagonism at low-dose levels and a synergism at high-dose levels in combination with diclofenac or irgasan, when using the NRU and the AlamarBlue assay. The dose-response surface of irgasan and diclofenac indicated a concentration addition. The experimental data could be described by the algorithms with a regression of up to 90%, revealing the HepG2 cell line and the MIXTOX model as valuable tool for risk assessment of binary mixtures for cytotoxic endpoints. However the model failed to predict a specific mode of action, the CYP1A1 enzyme activity.
Young and Waltzing Binary Stars
2001-10-01
stars heat up enough to start nuclear burning. When infant stars in RXJ 0529.4+0041 eventually reach middle-age, their sizes will most likely also be quite similar to that of the Sun. The significance of RXJ 0529.4+0041 Few systems are known for which such precise determinations of the stellar parameters have ever been possible - and this binary system represents the first case where both the components are such young stars . A detailed comparison of the derived stellar parameters with current models for the evolution of young stars shows fairly good agreement for the primary component. However, there are certain discrepancies in the case of the secondary component, showing that the current models for the early stages of lower-mass stars must still be refined. More information Part of the results described in this press release are described in more detail in a scientific article ( "RXJ 0529.4+0041: a low-mass pre-main sequence eclipsing-spectroscopic binary" by E. Covino et al.) that has been published in the European research journal Astronomy & Astrophysics (Vol. 361, p. 49). Notes [1] The team consists of Elvira Covino (Principal Investigator), Juan M. Alcalá , Rosita Paladino (all Osservatorio Astronomico di Capodimonte, Napoli, Italy), Antonio Frasca , Santo Catalano , Ettore Marilli (all Osservatorio Astrofisico di Catania, Italy) and Michael Sterzik (ESO-Chile). [2] One solar mass corresponds to 1.99 10 30 kg, or about 330,000 times the mass of the Earth. The Sun is about 4500 million years old and its total lifetime is of the order of 12-13,000 million years. It is an interesting thought that if the Sun would have been somewhat heavier, its total lifetime might have been too short for living organisms to develop on the Earth. In fact, the biological evolution that ultimately lead to the emergence of human beings apparently lasted about 4 billion years; this corresponds to the total lifetime of a star that is only about 20 % heavier than the Sun. Note also the
A nuclear data acquisition system flow control model
International Nuclear Information System (INIS)
Hack, S.N.
1988-01-01
A general Petri Net representation of a nuclear data acquisition system model is presented. This model provides for the unique requirements of a nuclear data acquisition system including the capabilities of concurrently acquiring asynchronous and synchronous data, of providing multiple priority levels of flow control arbitration, and of permitting multiple input sources to reside at the same priority without the problem of channel lockout caused by a high rate data source. Finally, a previously implemented gamma camera/physiological signal data acquisition system is described using the models presented
DEFF Research Database (Denmark)
Cismondi, Martin; Mollerup, Jørgen M.; Zabaloy, Marcelo S.
2010-01-01
for a great diversity of mixtures. Nevertheless, the models for representing phase equilibria and physico-chemical properties of asymmetric systems may require more flexible mixing rules than the classical quadratic van der Waals (vdW) mixing rules or their equivalent (with regard to the number of available...... interaction parameters) in modern equations of state.In particular, the phase equilibria of binary mixtures containing CO2 and heavy n-alkanes have been studied by an important number of authors and using different types of models, achieving only partially accurate results and realizing the difficulties...
Development of ITER 3D neutronics model and nuclear analyses
International Nuclear Information System (INIS)
Zeng, Q.; Zheng, S.; Lu, L.; Li, Y.; Ding, A.; Hu, H.; Wu, Y.
2007-01-01
ITER nuclear analyses rely on the calculations with the three-dimensional (3D) Monte Carlo code e.g. the widely-used MCNP. However, continuous changes in the design of the components require the 3D neutronics model for nuclear analyses should be updated. Nevertheless, the modeling of a complex geometry with MCNP by hand is a very time-consuming task. It is an efficient way to develop CAD-based interface code for automatic conversion from CAD models to MCNP input files. Based on the latest CAD model and the available interface codes, the two approaches of updating 3D nuetronics model have been discussed by ITER IT (International Team): The first is to start with the existing MCNP model 'Brand' and update it through a combination of direct modification of the MCNP input file and generation of models for some components directly from the CAD data; The second is to start from the full CAD model, make the necessary simplifications, and generate the MCNP model by one of the interface codes. MCAM as an advanced CAD-based MCNP interface code developed by FDS Team in China has been successfully applied to update the ITER 3D neutronics model by adopting the above two approaches. The Brand model has been updated to generate portions of the geometry based on the newest CAD model by MCAM. MCAM has also successfully performed conversion to MCNP neutronics model from a full ITER CAD model which is simplified and issued by ITER IT to benchmark the above interface codes. Based on the two updated 3D neutronics models, the related nuclear analyses are performed. This paper presents the status of ITER 3D modeling by using MCAM and its nuclear analyses, as well as a brief introduction of advanced version of MCAM. (authors)
International Nuclear Information System (INIS)
Kermanpour, F.; Sharifi, T.
2012-01-01
Highlights: ► Densities and viscosities for binary mixture of {x 1 [C 6 mim][BF 4 ] + x 2 1-propanol} were measured at different temperatures. ► The excess molar functions were calculated from the obtained experimental data. ► These data were correlated with the Redlich–Kister equation and PFP model to obtain the coefficients and standard deviations. - Abstract: Densities, ρ, and viscosities, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoro borate ([C 6 mim][BF 4 ]) and 1-propanol, and their binary mixture {x 1 [C 6 mim][BF 4 ] + x 2 1-propanol} were measured at atmospheric pressure and in the temperature range of 293.15–333.15 K. The excess molar volumes, V m E , thermal expansion coefficients, α, and their excess values, α E , isothermal coefficient of excess molar enthalpy, (∂H m E /∂p) T,x and excess viscosities, η E , were calculated from the experimental values of densities and viscosities. The excess molar volumes of the binary mixture are negative over the entire mole fraction range and increase with increasing temperature. Excess viscosities are negative over the entire mole fraction range of the mixture and decrease with increasing temperature. The obtained excess molar volumes and excess viscosities were correlated with the Redlich–Kister equation. The experimental results have also been used to examine the applicability of Prigogine–Flory–Patterson (PFP) theory in predicting the excess molar volume of the binary mixture. It is indicated that agreement between excess molar volumes calculated via PFP theory and the experimental results is good in all temperatures.
Validating neural-network refinements of nuclear mass models
Utama, R.; Piekarewicz, J.
2018-01-01
Background: Nuclear astrophysics centers on the role of nuclear physics in the cosmos. In particular, nuclear masses at the limits of stability are critical in the development of stellar structure and the origin of the elements. Purpose: We aim to test and validate the predictions of recently refined nuclear mass models against the newly published AME2016 compilation. Methods: The basic paradigm underlining the recently refined nuclear mass models is based on existing state-of-the-art models that are subsequently refined through the training of an artificial neural network. Bayesian inference is used to determine the parameters of the neural network so that statistical uncertainties are provided for all model predictions. Results: We observe a significant improvement in the Bayesian neural network (BNN) predictions relative to the corresponding "bare" models when compared to the nearly 50 new masses reported in the AME2016 compilation. Further, AME2016 estimates for the handful of impactful isotopes in the determination of r -process abundances are found to be in fairly good agreement with our theoretical predictions. Indeed, the BNN-improved Duflo-Zuker model predicts a root-mean-square deviation relative to experiment of σrms≃400 keV. Conclusions: Given the excellent performance of the BNN refinement in confronting the recently published AME2016 compilation, we are confident of its critical role in our quest for mass models of the highest quality. Moreover, as uncertainty quantification is at the core of the BNN approach, the improved mass models are in a unique position to identify those nuclei that will have the strongest impact in resolving some of the outstanding questions in nuclear astrophysics.
Nuclear reactor power control system based on flexibility model
International Nuclear Information System (INIS)
Li Gang; Zhao Fuyu; Li Chong; Tai Yun
2011-01-01
Design the nuclear reactor power control system in this paper to cater to a nonlinear nuclear reactor. First, calculate linear power models at five power levels of the reactor as five local models and design controllers of the local models as local controllers. Every local controller consists of an optimal controller contrived by the toolbox of Optimal Controller Designer (OCD) and a proportion-integration-differentiation (PID) controller devised via Genetic Algorithm (GA) to set parameters of the PID controller. According to the local models and controllers, apply the principle of flexibility model developed in the paper to obtain the flexibility model and the flexibility controller at every power level. Second, the flexibility model and the flexibility controller at a level structure the power control system of this level. The set of the whole power control systems corresponding to global power levels is to approximately carry out the power control of the reactor. Finally, the nuclear reactor power control system is simulated. The simulation result shows that the idea of flexibility model is feasible and the nuclear reactor power control system is effective. (author)
Modeling the optimal management of spent nuclear fuel
International Nuclear Information System (INIS)
Nachlas, J.A.; Kurstedt, H.A. Jr.; Swindle, D.W. Jr.; Korcz, K.O.
1977-01-01
Recent governmental policy decisions dictate that strategies for managing spent nuclear fuel be developed. Two models are constructed to investigate the optimum residence time and the optimal inventory withdrawal policy for fuel material that presently must be stored. The mutual utility of the models is demonstrated through reference case application
ENVI Model Development for Korean Nuclear Spent Fuel Options Analysis
Energy Technology Data Exchange (ETDEWEB)
Chang, Sunyoung; Jeong, Yon Hong; Han, Jae-Jun; Lee, Aeri; Hwang, Yong-Soo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)
2015-10-15
The disposal facility of the spent nuclear fuel will be operated from 2051. This paper presents the ENVI code developed by GoldSim Software to simulate options for managing spent nuclear fuel (SNF) in South Korea. The ENVI is a simulator to allow decision-makers to assist to evaluate the performance for spent nuclear fuel management. The multiple options for managing the spent nuclear fuel including the storage and transportation are investigated into interim storage, permanent disposal in geological repositories and overseas and domestic reprocessing. The ENVI code uses the GoldSim software to simulate the logistics of the associated activities. The result by the ENVI model not only produces the total cost to compare among the multiple options but also predict the sizes and timings of different facilities required. In order to decide the policy for spent nuclear management this purpose of this paper is to draw the optimum management plan to solve the nuclear spent fuel issue in the economical aspects. This paper is focused on the development of the ENVI's logic and calculations to simulate four options(No Reprocessing, Overseas Reprocessing, Domestic Reprocessing, and Overseas and Domestic Reprocessing) for managing the spent nuclear fuel in South Korea. The time history of the spent nuclear fuel produced from both the existing and future NPP's can be predicted, based on the Goldsim software made available very user friendly model. The simulation result will be used to suggest the strategic plans for the spent nuclear fuel management.
ENVI Model Development for Korean Nuclear Spent Fuel Options Analysis
International Nuclear Information System (INIS)
Chang, Sunyoung; Jeong, Yon Hong; Han, Jae-Jun; Lee, Aeri; Hwang, Yong-Soo
2015-01-01
The disposal facility of the spent nuclear fuel will be operated from 2051. This paper presents the ENVI code developed by GoldSim Software to simulate options for managing spent nuclear fuel (SNF) in South Korea. The ENVI is a simulator to allow decision-makers to assist to evaluate the performance for spent nuclear fuel management. The multiple options for managing the spent nuclear fuel including the storage and transportation are investigated into interim storage, permanent disposal in geological repositories and overseas and domestic reprocessing. The ENVI code uses the GoldSim software to simulate the logistics of the associated activities. The result by the ENVI model not only produces the total cost to compare among the multiple options but also predict the sizes and timings of different facilities required. In order to decide the policy for spent nuclear management this purpose of this paper is to draw the optimum management plan to solve the nuclear spent fuel issue in the economical aspects. This paper is focused on the development of the ENVI's logic and calculations to simulate four options(No Reprocessing, Overseas Reprocessing, Domestic Reprocessing, and Overseas and Domestic Reprocessing) for managing the spent nuclear fuel in South Korea. The time history of the spent nuclear fuel produced from both the existing and future NPP's can be predicted, based on the Goldsim software made available very user friendly model. The simulation result will be used to suggest the strategic plans for the spent nuclear fuel management
International Nuclear Information System (INIS)
Sun, S.P.; Yi, D.Q.; Liu, H.Q.; Zang, B.; Jiang, Y.
2010-01-01
Research highlights: → A method based on semi-empirical Miedema's and Toop's model for predicting glass forming range of ternary alloy system has been systematically described. → The method is superior to conventional models by considering the effect of the thermodynamic asymmetric component when dealing with a ternary alloy system. → The glass forming ranges of Al-Ni-RE (Al-Ni-Ce, Al-Ni-Y and Al-Ni-La) systems and their sub-binaries have been successfully calculated. → The present calculations using the method are in well agreement with experiments. → This model is especially useful for predicting the glass forming range of ternary alloy system because the calculations do not require experimental data. - Abstract: A method based on the semi-empirical Miedema's and Toop's model for calculating the glass forming range of a ternary alloy system was systematically described. The method is superior to conventional models by considering the effect of the thermodynamic asymmetric component when dealing with a ternary alloy system. Using this method, the glass forming ranges of Al-Ni-RE (Ce, La, Y) systems and their sub-binaries were successfully predicted. The mixing enthalpy and mismatch entropy were calculated, and their effects on the glass forming abilities of Al-Ni-RE (Ce, La, Y) systems were also discussed. The glass forming abilities of Al-Ni-Ce, Al-Ni-La and Al-Ni-Y are found to be close. The calculated glass forming ranges agree with experiments well. Meanwhile, the enthalpy change from amorphous phase to solid solution in the glass forming ranges was calculated, and the results suggest that those alloys close to the Ni-RE sub-binary system have higher glass forming abilities.
Model integration and the economics of nuclear power
International Nuclear Information System (INIS)
Lundgren, S.
1985-01-01
The author proposes and applies a specific approach to model integration, i.e. the merger of two or several independently developed models. The approach is intended for integrations of activity analysis sector models and applied general equilibrium models. Model integration makes it possible to extend the range of applicability of applied general equilibrium models by exploiting the information contained in sector models. It also makes it possible to evaluate the validity of the partial equilibrium analyses in which sector models often are employed. The proposed approach is used to integrate a sector model of electricity and heat production with a general equilibrium model of the Swedish economy. Both models have been constructed within the research programme. The author uses the integrated model to look at two issues concerning the role of nuclear power on the Swedish electricity market: What are the likely consequences of a nuclear power discontinuation and how does the nuclear power investment programme of the 1970's and the early 1980's compare with a socially efficient one. (Author)
Nuclear surface vibrations in bag models
International Nuclear Information System (INIS)
Tomio, L.
1984-01-01
The main difficulties found in the hadron bag models are reviewed from the original version of the MIT bag model. Following, with the aim to answer two of the main difficulties in bag models, viz., the parity and the divergence illness, a dynamical model is presented. In the model, the confinement surface of the quarks (bag) is treated like a real physical object which interacts with the quarks and is exposed to vibrations. The model is applied to the nucleon, being observed that his spectrum, in the first excited levels, can be reproduced with resonable precision and obeying to the correct parity order. In the same way that in a similar work of Brown et al., it is observed to be instrumental the inclusion of the effect due to pions. (L.C.) [pt
Utomo, P.H.; Makarim, R.H.
2017-01-01
A Binary puzzle is a Sudoku-like puzzle with values in each cell taken from the set {0,1} {0,1}. Let n≥4 be an even integer, a solved binary puzzle is an n×n binary array that satisfies the following conditions: (1) no three consecutive ones and no three consecutive zeros in each row and each
Schematic model of nuclear spin excitations
International Nuclear Information System (INIS)
Boucher, P.M.
1990-01-01
A simple model to estimate the strength of spin and nonspin collective states is presented. The model was inspired by early schematic models based on energy-weighted sum rules and is a useful tool for interpreting experimental data without the complexities of realistic microscopic calculations. The strength of collective states is calculated by assuming that a single collective state completely exhausts the energy-weighted sum rule. 19 refs
Health effects models for nuclear power plant accident consequence analysis
International Nuclear Information System (INIS)
Abrahamson, S.; Bender, M.A.; Boecker, B.B.; Scott, B.R.
1993-05-01
The Nuclear Regulatory Commission (NRC) has sponsored several studies to identify and quantify, through the use of models, the potential health effects of accidental releases of radionuclides from nuclear power plants. The Reactor Safety Study provided the basis for most of the earlier estimates related to these health effects. Subsequent efforts by NRC-supported groups resulted in improved health effects models that were published in the report entitled open-quotes Health Effects Models for Nuclear Power Plant Consequence Analysisclose quotes, NUREG/CR-4214, 1985 and revised further in the 1989 report NUREG/CR-4214, Rev. 1, Part 2. The health effects models presented in the 1989 NUREG/CR-4214 report were developed for exposure to low-linear energy transfer (LET) (beta and gamma) radiation based on the best scientific information available at that time. Since the 1989 report was published, two addenda to that report have been prepared to (1) incorporate other scientific information related to low-LET health effects models and (2) extend the models to consider the possible health consequences of the addition of alpha-emitting radionuclides to the exposure source term. The first addendum report, entitled open-quotes Health Effects Models for Nuclear Power Plant Accident Consequence Analysis, Modifications of Models Resulting from Recent Reports on Health Effects of Ionizing Radiation, Low LET Radiation, Part 2: Scientific Bases for Health Effects Models,close quotes was published in 1991 as NUREG/CR-4214, Rev. 1, Part 2, Addendum 1. This second addendum addresses the possibility that some fraction of the accident source term from an operating nuclear power plant comprises alpha-emitting radionuclides. Consideration of chronic high-LET exposure from alpha radiation as well as acute and chronic exposure to low-LET beta and gamma radiations is a reasonable extension of the health effects model
Eclipsing binaries in open clusters
DEFF Research Database (Denmark)
Southworth, John; Clausen, J.V.
2006-01-01
Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...
Modeling of H- surface conversion sources; binary (H-Ba) and ternary (H-Cs/W) converter arrangements
International Nuclear Information System (INIS)
van Os, C.F.A.; Kunkel, W.B.; Leguijt, C.; Los, J.
1991-01-01
The production process for the formation of H - ions in a surface conversion source is sputtering of hydrogen atoms from the converter surface layers by incident positive ions, followed by electron attachment via resonant charge exchange with the converter surface. The sputtering process is in direct relation to the converter surface composition. New experimental data led us to identify two different classes of converters: metallic converters, like solid barium(binary) and adlayer converters, like cesium on tungsten (ternary). For a binary converter the hydrogen in the surface layers is directly sputtered by the incoming ions. Consequently, the negative ion yield scales with the hydrogen concentration in the surface layers. In the cesium/tungsten system (ternary) the hydrogen at the surface is believed to be sandwiched between the cesium adlayer and the tungsten surface. Hence, the negative ion yield scales with the sputter coefficient of hydrogen on adsorbed cesium. This is experimentally confirmed
International Nuclear Information System (INIS)
Majstorović, Divna M.; Živković, Emila M.; Matija, Lidija R.; Kijevčanin, Mirjana Lj.
2017-01-01
Highlights: • Densitis and viscosities of four ester + alcohol binary mixtures were measured. • Excess and deviation functions were calculated. • Fourier transform infrared (FT-IR) spectroscopy analysis was conducted. • Molecular interactions present in the mixture were analyzed. • Viscosity modelling was performed. - Abstract: Density, viscosity and refractive index of four binary mixtures consisting of diethyl succinate or ethyl octanoate + 2-methyl-1-propanol or 3-methyl-1-butanol have been measured at atmospheric pressure and over the temperature range from 288.15 K to 323.15 K. Excess and deviation functions have been calculated from these data and fitted to the Redlich-Kister equation. The values of excess molar volume and deviation functions, with FT-IR study, were further used in the analysis of molecular interactions present in the mixture as well as the temperature influence on them. Molar excess Gibbs free energies of activation of viscous flow were additionally calculated from measured density and viscosity data for better understanding of present molecular interactions. Viscosity modelling was done with two approaches, predictive by group contribution models (UNIFAC-VISCO and ASOG-VISCO), and correlative by one to three-parameter models (Teja-Rice, Grunberg–Nissan, McAlister, Eyring-UNIQUAC and Eyring-NRTL). The obtained results were compared with experimental data and conclusions about applied approaches and models were made.
International Nuclear Information System (INIS)
Browarzik, Dieter; Langenbach, Kai; Enders, Sabine; Browarzik, Christina
2013-01-01
Highlights: ► Liquid–liquid equilibrium (LLE) is calculated with the lattice–cluster theory (LCT). ► Equations of the LCT are reduced to only three geometrical parameters. ► Branching influence on the LLE is modeled for binary and ternary polymer solutions. ► Branched and linear solvents and polymers are compared in their influence on LLE. ► Solutions of branched polymers in branched solvents show the best miscibility. -- Abstract: The liquid–liquid equilibrium (LLE) of ternary model systems of the type solvent A + polymer B + solvent C is treated in the framework of lattice–cluster theory (LCT). There are a linear and a branched type of A-molecules as well as a linear and two types of strongly branched polymer molecules. The C-molecules are assumed to occupy only one lattice site. For nine binary and six ternary polymer solutions the branching influence on LLE is discussed. Currently, the LCT is the most useful model to take the architecture of the molecules into account. However, particularly for ternary systems the model is not comfortable because of the very numerous terms of the Gibbs energy. Using some relationships between the geometrical parameters of the model a considerable simplification is possible. In this paper the new and simpler equations of the LCT are presented. For comparison with experimental data critical temperatures of solutions of linear and branched polyethylene samples in diphenyl ether are calculated
Obeidat, Abdalla; Abu-Ghazleh, Hind
2018-06-01
Two intermolecular potential models of methanol (TraPPE-UA and OPLS-AA) have been used in order to examine their validity in reproducing the selected structural, dynamical, and thermodynamic properties in the unary and binary systems. These two models are combined with two water models (SPC/E and TIP4P). The temperature dependence of density, surface tension, diffusion and structural properties for the unary system has been computed over specific range of temperatures (200-300K). The very good performance of the TraPPE-UA potential model in predicting surface tension, diffusion, structure, and density of the unary system led us to examine its accuracy and performance in its aqueous solution. In the binary system the same properties were examined, using different mole fractions of methanol. The TraPPE-UA model combined with TIP4P-water shows a very good agreement with the experimental results for density and surface tension properties; whereas the OPLS-AA combined with SPCE-water shows a very agreement with experimental results regarding the diffusion coefficients. Two different approaches have been used in calculating the diffusion coefficient in the mixture, namely the Einstein equation (EE) and Green-Kubo (GK) method. Our results show the advantageous of applying GK over EE in reproducing the experimental results and in saving computer time.
Nuclear facility safeguards systems modeling using discrete event simulation
International Nuclear Information System (INIS)
Engi, D.
1977-01-01
The threat of theft or dispersal of special nuclear material at a nuclear facility is treated by studying the temporal relationships between adversaries having authorized access to the facility (insiders) and safeguards system events by using a GASP IV discrete event simulation. The safeguards system events--detection, assessment, delay, communications, and neutralization--are modeled for the general insider adversary strategy which includes degradation of the safeguards system elements followed by an attempt to steal or disperse special nuclear material. The performance measure used in the analysis is the estimated probability of safeguards system success in countering the adversary based upon a predetermined set of adversary actions. An exemplary problem which includes generated results is presented for a hypothetical nuclear facility. The results illustrate representative information that could be utilized by safeguards decision-makers
Numerical simulation of interior flow field of nuclear model pump
International Nuclear Information System (INIS)
Wang Chunlin; Peng Na; Kang Can; Zhao Baitong; Zhang Hao
2009-01-01
Reynolds time-averaged N-S equations and the standard k-ε turbulent model were adopted, and three-dimensional non-structural of tetrahedral mesh division was used for modeling. Multiple reference frame model of rotating fluid mechanical model was used, under the design condition, the three-dimensional incompressible turbulent flow of nuclear model pump was simulated, and the results preferably post the characteristics of the interior flow field. This paper first analyzes the total pressure and velocity distribution in the flow field, and then describes the interior flow field characteristics of each part such as the impeller, diffuser and spherical shell, and also discusses the reasons that cause these characteristics. The study results can be used to estimate the performance of nuclear model pump, and will provide some useful references for its hydraulic optimized design. (authors)
Self-consistent mean-field models for nuclear structure
International Nuclear Information System (INIS)
Bender, Michael; Heenen, Paul-Henri; Reinhard, Paul-Gerhard
2003-01-01
The authors review the present status of self-consistent mean-field (SCMF) models for describing nuclear structure and low-energy dynamics. These models are presented as effective energy-density functionals. The three most widely used variants of SCMF's based on a Skyrme energy functional, a Gogny force, and a relativistic mean-field Lagrangian are considered side by side. The crucial role of the treatment of pairing correlations is pointed out in each case. The authors discuss other related nuclear structure models and present several extensions beyond the mean-field model which are currently used. Phenomenological adjustment of the model parameters is discussed in detail. The performance quality of the SCMF model is demonstrated for a broad range of typical applications
Fuzzy model-based control of a nuclear reactor
International Nuclear Information System (INIS)
Van Den Durpel, L.; Ruan, D.
1994-01-01
The fuzzy model-based control of a nuclear power reactor is an emerging research topic world-wide. SCK-CEN is dealing with this research in a preliminary stage, including two aspects, namely fuzzy control and fuzzy modelling. The aim is to combine both methodologies in contrast to conventional model-based PID control techniques, and to state advantages of including fuzzy parameters as safety and operator feedback. This paper summarizes the general scheme of this new research project
Simulation model of nuclear power plant turbine
International Nuclear Information System (INIS)
Dutta, Anu; Thangamani, I.; Chakraborty, G.; Ghosh, A.K.
2006-04-01
A computer code TURDYN has been developed for prediction of HP and LP turbine torque under thermodynamic transient conditions. The model is based on the conservation laws of mass and energy. All the important components of turbine systems e.g. high pressure turbine, low pressure turbine, feed heaters, reheater, moisture separator have been considered. The details of the mathematical formulation of the model and open loop responses for specific disturbances are presented. (author)
A model for nuclear research reactor dynamics
Energy Technology Data Exchange (ETDEWEB)
Barati, Ramin, E-mail: Barati.ramin@aut.ac.ir; Setayeshi, Saeed, E-mail: setayesh@aut.ac.ir
2013-09-15
Highlights: • A thirty-fourth order model is used to simulate the dynamics of a research reactor. • We consider delayed neutrons fraction as a function of time. • Variable fuel and temperature reactivity coefficients are used. • WIMS, BORGES and CITVAP codes are used for initial condition calculations. • Results are in agreement with experimental data rather than common codes. -- Abstract: In this paper, a useful thirty-fourth order model is presented to simulate the kinetics and dynamics of a research reactor core. The model considers relevant physical phenomena that govern the core such as reactor kinetics, reactivity feedbacks due to coolant and fuel temperatures (Doppler effects) with variable reactivity coefficients, xenon, samarium, boron concentration, fuel burn up and thermal hydraulics. WIMS and CITVAP codes are used to extract neutron cross sections and calculate the initial neuron flux respectively. The purpose is to present a model with results similar to reality as much as possible with reducing common simplifications in reactor modeling to be used in different analyses such as reactor control, functional reliability and safety. The model predictions are qualified by comparing with experimental data, detailed simulations of reactivity insertion transients, and steady state for Tehran research reactor reported in the literature and satisfactory results have been obtained.
Hidden slow pulsars in binaries
Tavani, Marco; Brookshaw, Leigh
1993-01-01
The recent discovery of the binary containing the slow pulsar PSR 1718-19 orbiting around a low-mass companion star adds new light on the characteristics of binary pulsars. The properties of the radio eclipses of PSR 1718-19 are the most striking observational characteristics of this system. The surface of the companion star produces a mass outflow which leaves only a small 'window' in orbital phase for the detection of PSR 1718-19 around 400 MHz. At this observing frequency, PSR 1718-19 is clearly observable only for about 1 hr out of the total 6.2 hr orbital period. The aim of this Letter is twofold: (1) to model the hydrodynamical behavior of the eclipsing material from the companion star of PSR 1718-19 and (2) to argue that a population of binary slow pulsars might have escaped detection in pulsar surveys carried out at 400 MHz. The possible existence of a population of partially or totally hidden slow pulsars in binaries will have a strong impact on current theories of binary evolution of neutron stars.
Design of nuclear power generation plants adopting model engineering method
International Nuclear Information System (INIS)
Waki, Masato
1983-01-01
The utilization of model engineering as the method of design has begun about ten years ago in nuclear power generation plants. By this method, the result of design can be confirmed three-dimensionally before actual production, and it is the quick and sure method to meet the various needs in design promptly. The adoption of models aims mainly at the improvement of the quality of design since the high safety is required for nuclear power plants in spite of the complex structure. The layout of nuclear power plants and piping design require the model engineering to arrange rationally enormous quantity of things in a limited period. As the method of model engineering, there are the use of check models and of design models, and recently, the latter method has been mainly taken. The procedure of manufacturing models and engineering is explained. After model engineering has been completed, the model information must be expressed in drawings, and the automation of this process has been attempted by various methods. The computer processing of design is in progress, and its role is explained (CAD system). (Kako, I.)
Infinite nuclear matter model and mass formulae for nuclei
International Nuclear Information System (INIS)
Satpathy, L.
2016-01-01
The matter composed of the nucleus is a quantum-mechanical interacting many-fermionic system. However, the shell and classical liquid drop have been taken as the two main features of nuclear dynamics, which have guided the evolution of nuclear physics. These two features can be considered as the macroscopic manifestation of the microscopic dynamics of the nucleons at fundamental level. Various mass formulae have been developed based on either of these features over the years, resulting in many ambiguities and uncertainties posing many challenges in this field. Keeping this in view, Infinite Nuclear Matter (INM) model has been developed during last couple of decades with a many-body theoretical foundation employing the celebrated Hugenholtz-Van Hove theorem, quite appropriate for the interacting quantum-mechanical nuclear system. A mass formula called INM mass formula based on this model yields rms deviation of 342 keV being the lowest in literature. Some of the highlights of its result includes its determination of INM density in agreement with the electron scattering data leading to the resolution of the long standing 'r 0 -paradox' it predicts new magic numbers giving rise to new island of stability in the drip-line regions. This is the manifestation of a new phenomenon where shell-effect over comes the repulsive component of nucleon-nucleon force resulting in the broadening of the stability peninsula. Shell quenching in N= 82,and N= 126 shells, and several islands of inversion have been predicted. The model determines the empirical value of the nuclear compression modulus, using high precission 4500 data comprising nuclear masses, neutron and proton separation energies. The talk will give a critical review of the field of mass formula and our understanding of nuclear dynamics as a whole
Common modelling approaches for training simulators for nuclear power plants
International Nuclear Information System (INIS)
1990-02-01
Training simulators for nuclear power plant operating staff have gained increasing importance over the last twenty years. One of the recommendations of the 1983 IAEA Specialists' Meeting on Nuclear Power Plant Training Simulators in Helsinki was to organize a Co-ordinated Research Programme (CRP) on some aspects of training simulators. The goal statement was: ''To establish and maintain a common approach to modelling for nuclear training simulators based on defined training requirements''. Before adapting this goal statement, the participants considered many alternatives for defining the common aspects of training simulator models, such as the programming language used, the nature of the simulator computer system, the size of the simulation computers, the scope of simulation. The participants agreed that it was the training requirements that defined the need for a simulator, the scope of models and hence the type of computer complex that was required, the criteria for fidelity and verification, and was therefore the most appropriate basis for the commonality of modelling approaches. It should be noted that the Co-ordinated Research Programme was restricted, for a variety of reasons, to consider only a few aspects of training simulators. This report reflects these limitations, and covers only the topics considered within the scope of the programme. The information in this document is intended as an aid for operating organizations to identify possible modelling approaches for training simulators for nuclear power plants. 33 refs
Three-dimensional modeling of nuclear steam generator
International Nuclear Information System (INIS)
Bogdan, Z.; Afgan, N.
1985-01-01
In this paper mathematical model for steady-state simulation of thermodynamic and hydraulic behaviour of U-tube nuclear steam generator is described. The model predicts three-dimensional distribution of temperatures, pressures, steam qualities and velocities in the steam generator secondary loop. In this analysis homogeneous two phase flow model is utilized. Foe purpose of the computer implementation of the mathematical model, a special flow distribution code NUGEN was developed. Calculations are performed with the input data and geometrical characteristics related to the D-4 (westinghouse) model of U-tube nuclear steam generator built in Krsko, operating under 100% load conditions. Results are shown in diagrams giving spatial distribution of pertinent variables in the secondary loop. (author)
Relativistic nuclear matter with alternative derivative coupling models
International Nuclear Information System (INIS)
Delfino, A.; Coelho, C.T.; Malheiro, M.
1994-01-01
Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-field theory. The study presents the traditional Walecka model and different kinds of scalar derivative coupling suggested by Zimanyi and Moszkowski. The incompressibility (presented in an analytical form), scalar potential, and vector potential at the saturation point of nuclear matter are compared for these models. The real optical potential for the models are calculated and one of the models fits well the experimental curve from-50 to 400 MeV while also gives a soft equation of state. By varying the coupling constants and keeping the saturation point of nuclear matter approximately fixed, only the Walecka model presents a first order phase transition of finite temperature at zero density. (author)
Multiscale Modeling and Uncertainty Quantification for Nuclear Fuel Performance
Energy Technology Data Exchange (ETDEWEB)
Estep, Donald [Colorado State Univ., Fort Collins, CO (United States); El-Azab, Anter [Florida State Univ., Tallahassee, FL (United States); Pernice, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Peterson, John W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Polyakov, Peter [Univ. of Wyoming, Laramie, WY (United States); Tavener, Simon [Colorado State Univ., Fort Collins, CO (United States); Xiu, Dongbin [Purdue Univ., West Lafayette, IN (United States); Univ. of Utah, Salt Lake City, UT (United States)
2017-03-23
In this project, we will address the challenges associated with constructing high fidelity multiscale models of nuclear fuel performance. We (*) propose a novel approach for coupling mesoscale and macroscale models, (*) devise efficient numerical methods for simulating the coupled system, and (*) devise and analyze effective numerical approaches for error and uncertainty quantification for the coupled multiscale system. As an integral part of the project, we will carry out analysis of the effects of upscaling and downscaling, investigate efficient methods for stochastic sensitivity analysis of the individual macroscale and mesoscale models, and carry out a posteriori error analysis for computed results. We will pursue development and implementation of solutions in software used at Idaho National Laboratories on models of interest to the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program.
Application of 3-dimensional CAD modeling system in nuclear plants
International Nuclear Information System (INIS)
Suwa, Minoru; Saito, Shunji; Nobuhiro, Minoru
1990-01-01
Until now, the preliminary work for mutual components in nuclear plant were readied by using plastic models. Recently with the development of computer graphic techniques, we can display the components on the graphics terminal, better than with use of plastic model and actual plants. The computer model can be handled, both telescopically and microscopically. A computer technique called 3-dimensional CAD modeling system was used as the preliminary work and design system. Through application of this system, database for nuclear plants was completed in arrangement step. The data can be used for piping design, stress analysis, shop production, testing and site construction, in all steps. In addition, the data can be used for various planning works, even after starting operation of plant. This paper describes the outline of the 3-dimensional CAD modeling system. (author)
Nuclear reactor fuel rod behavior modelling and current trends
International Nuclear Information System (INIS)
Colak, Ue.
2001-01-01
Safety assessment of nuclear reactors is carried out by simulating the events to taking place in nuclear reactors by realistic computer codes. Such codes are developed in a way that each event is represented by differential equations derived based on physical laws. Nuclear fuel is an important barrier against radioactive fission gas release. The release of radioactivity to environment is the main concern and this can be avoided by preserving the integrity of fuel rod. Therefore, safety analyses should cover an assessment of fuel rod behavior with certain extent. In this study, common approaches for fuel behavior modeling are discussed. Methods utilized by widely accepted computer codes are reviewed. Shortcomings of these methods are explained. Current research topics to improve code reliability and problems encountered in fuel rod behavior modeling are presented
The Gogny-Hartree-Fock-Bogoliubov nuclear-mass model
Energy Technology Data Exchange (ETDEWEB)
Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium); Hilaire, S.; Girod, M.; Peru, S. [CEA, DAM, DIF, Arpajon (France)
2016-07-15
We present the Gogny-Hartree-Fock-Bogoliubov model which reproduces nuclear masses with an accuracy comparable with the best mass formulas. In contrast to the Skyrme-HFB nuclear-mass models, an explicit and self-consistent account of all the quadrupole correlation energies is included within the 5D collective Hamiltonian approach. The final rms deviation with respect to the 2353 measured masses is 789 keV in the 2012 atomic mass evaluation. In addition, the D1M Gogny force is shown to predict nuclear and neutron matter properties in agreement with microscopic calculations based on realistic two- and three-body forces. The D1M properties and its predictions of various observables are compared with those of D1S and D1N. (orig.)
Integrated multi-scale modelling and simulation of nuclear fuels
International Nuclear Information System (INIS)
Valot, C.; Bertolus, M.; Masson, R.; Malerba, L.; Rachid, J.; Besmann, T.; Phillpot, S.; Stan, M.
2015-01-01
This chapter aims at discussing the objectives, implementation and integration of multi-scale modelling approaches applied to nuclear fuel materials. We will first show why the multi-scale modelling approach is required, due to the nature of the materials and by the phenomena involved under irradiation. We will then present the multiple facets of multi-scale modelling approach, while giving some recommendations with regard to its application. We will also show that multi-scale modelling must be coupled with appropriate multi-scale experiments and characterisation. Finally, we will demonstrate how multi-scale modelling can contribute to solving technology issues. (authors)
Organization model and formalized description of nuclear enterprise information system
International Nuclear Information System (INIS)
Yuan Feng; Song Yafeng; Li Xudong
2012-01-01
Organization model is one of the most important models of Nuclear Enterprise Information System (NEIS). Scientific and reasonable organization model is the prerequisite that NEIS has robustness and extendibility, and is also the foundation of the integration of heterogeneous system. Firstly, the paper describes the conceptual model of the NEIS on ontology chart, which provides a consistent semantic framework of organization. Then it discusses the relations between the concepts in detail. Finally, it gives the formalized description of the organization model of NEIS based on six-tuple array. (authors)
Modeling issues in nuclear plant fire risk analysis
International Nuclear Information System (INIS)
Siu, N.
1989-01-01
This paper discusses various issues associated with current models for analyzing the risk due to fires in nuclear power plants. Particular emphasis is placed on the fire growth and suppression models, these being unique to the fire portion of the overall risk analysis. Potentially significant modeling improvements are identified; also discussed are a variety of modeling issues where improvements will help the credibility of the analysis, without necessarily changing the computed risk significantly. The mechanistic modeling of fire initiation is identified as a particularly promising improvement for reducing the uncertainties in the predicted risk. 17 refs., 5 figs. 2 tabs
Yu, Yang; Michel, Patrick; Schwartz, Stephen R.; Naidu, Shantanu P.; Benner, Lance A. M.
2017-01-01
An understanding of the post-impact dynamics of ejecta clouds are crucial to the planning of a kinetic impact mission to an asteroid, and also has great implications for the history of planetary formation. The purpose of this article is to track the evolution of ejecta produced by AIDA mission, which targets for kinetic impact the secondary of near-Earth binary asteroid (65803) Didymos on 2022, and to feedback essential informations to AIDA's ongoing phase-A study. We present a detailed dynamic model for the simulation of an ejecta cloud from a binary asteroid that synthesizes all relevant forces based on a previous analysis of the mechanical environment. We apply our method to gain insight into the expected response of Didymos to the AIDA impact, including the subsequent evolution of debris and dust. The crater scaling relations from laboratory experiments are employed to approximate the distributions of ejecta mass and launching speed. The size distribution of fragments is modeled with a power law fitted from observations of real asteroid surface. A full-scale demonstration is simulated using parameters specified by the mission. We report the results of the simulation, which include the computed spread of the ejecta cloud and the recorded history of ejecta accretion and escape. The violent period of the ejecta evolution is found to be short, and is followed by a stage where the remaining ejecta is gradually cleared. Solar radiation pressure proves to be efficient in cleaning dust-size ejecta, and the simulation results after two weeks shows that large debris on polar orbits (perpendicular to the binary orbital plane) has a survival advantage over smaller ejecta and ejecta that keeps to low latitudes.
Koley, Bijoy Laxmi; Dey, Debangshu
2014-01-01
This paper presents an online method for automatic detection of apnea/hypopnea events, with the help of oxygen saturation (SpO2) signal, measured at fingertip by Bluetooth nocturnal pulse oximeter. Event detection is performed by identifying abnormal data segments from the recorded SpO2 signal, employing a binary classifier model based on a support vector machine (SVM). Thereafter the abnormal segment is further analyzed to detect different states within the segment, i.e., steady, desaturation, and resaturation, with the help of another SVM-based binary ensemble classifier model. Finally, a heuristically obtained rule-based system is used to identify the apnea/hypopnea events from the time-sequenced decisions of these classifier models. In the developmental phase, a set of 34 time domain-based features was extracted from the segmented SpO2 signal using an overlapped windowing technique. Later, an optimal set of features was selected on the basis of recursive feature elimination technique. A total of 34 subjects were included in the study. The results show average event detection accuracies of 96.7% and 93.8% for the offline and the online tests, respectively. The proposed system provides direct estimation of the apnea/hypopnea index with the help of a relatively inexpensive and widely available pulse oximeter. Moreover, the system can be monitored and accessed by physicians through LAN/WAN/Internet and can be extended to deploy in Bluetooth-enabled mobile phones.
Nuclear anapole moment and tests of the standard model
International Nuclear Information System (INIS)
Flambaum, V. V.
1999-01-01
There are two sources of parity nonconservation (PNC) in atoms: the electron-nucleus weak interaction and the magnetic interaction of electrons with the nuclear anapole moment. A nuclear anapole moment has recently been observed. This is the first discovery of an electromagnetic moment violating fundamental symmetries--the anapole moment violates parity and charge-conjugation invariance. We describe the anapole moment and how it can be produced. The anapole moment creates a circular magnetic field inside the nucleus. The interesting point is that measurements of the anapole allow one to study parity violation inside the nucleus through atomic experiments. We use the experimental result for the nuclear anapole moment of 133 Cs to find the strengths of the parity violating proton-nucleus and meson-nucleon forces. Measurements of the weak charge characterizing the strength of the electron-nucleon weak interaction provide tests of the Standard Model and a way of searching for new physics beyond the Standard Model. Atomic experiments give limits on the extra Z-boson, leptoquarks, composite fermions, and radiative corrections produced by particles that are predicted by new theories. The weak charge and nuclear anapole moment can be measured in the same experiment. The weak charge gives the mean value of the PNC effect while the anapole gives the difference of the PNC effects for the different hyperfine components of an electromagnetic transition. The interaction between atomic electrons and the nuclear anapole moment may be called the ''PNC hyperfine interaction.''
Overview of geochemical modeling needs for nuclear waste management
International Nuclear Information System (INIS)
Isherwood, D.J.; Wolery, T.J.
1985-01-01
Geochemical modeling needs for nuclear waste management are discussed with an emphasis on data base development and computer code. Other areas for future research include: precipitation kinetics, fixed fugacity, sorption, glasslt. slashwater interactions, redox disequilibrium and kinetics, radiolysis, solid solutions, and isotopic fractionation. 15 references
A different interpretation of the nuclear shell model
International Nuclear Information System (INIS)
Fabre de la Ripelle, M.
1984-12-01
In the first order approximation the nucleons are moving into a collective well extracted from the two-body N-N interaction. The nuclear shell model is explained by the structure of the first order solution of the Schroedinger equation. In the next step the two-body correlations generated by the N-N potential are introduced in the wave function
Statistical properties of the nuclear shell-model Hamiltonian
International Nuclear Information System (INIS)
Dias, H.; Hussein, M.S.; Oliveira, N.A. de
1986-01-01
The statistical properties of realistic nuclear shell-model Hamiltonian are investigated in sd-shell nuclei. The probability distribution of the basic-vector amplitude is calculated and compared with the Porter-Thomas distribution. Relevance of the results to the calculation of the giant resonance mixing parameter is pointed out. (Author) [pt
EMPIRE-II statistical model code for nuclear reaction calculations
Energy Technology Data Exchange (ETDEWEB)
Herman, M [International Atomic Energy Agency, Vienna (Austria)
2001-12-15
EMPIRE II is a nuclear reaction code, comprising various nuclear models, and designed for calculations in the broad range of energies and incident particles. A projectile can be any nucleon or Heavy Ion. The energy range starts just above the resonance region, in the case of neutron projectile, and extends up to few hundreds of MeV for Heavy Ion induced reactions. The code accounts for the major nuclear reaction mechanisms, such as optical model (SCATB), Multistep Direct (ORION + TRISTAN), NVWY Multistep Compound, and the full featured Hauser-Feshbach model. Heavy Ion fusion cross section can be calculated within the simplified coupled channels approach (CCFUS). A comprehensive library of input parameters covers nuclear masses, optical model parameters, ground state deformations, discrete levels and decay schemes, level densities, fission barriers (BARFIT), moments of inertia (MOMFIT), and {gamma}-ray strength functions. Effects of the dynamic deformation of a fast rotating nucleus can be taken into account in the calculations. The results can be converted into the ENDF-VI format using the accompanying code EMPEND. The package contains the full EXFOR library of experimental data. Relevant EXFOR entries are automatically retrieved during the calculations. Plots comparing experimental results with the calculated ones can be produced using X4TOC4 and PLOTC4 codes linked to the rest of the system through bash-shell (UNIX) scripts. The graphic user interface written in Tcl/Tk is provided. (author)
Psychometric model for safety culture assessment in nuclear research facilities
International Nuclear Information System (INIS)
Nascimento, C.S. do; Andrade, D.A.; Mesquita, R.N. de
2017-01-01
Highlights: • A psychometric model to evaluate ‘safety climate’ at nuclear research facilities. • The model presented evidences of good psychometric qualities. • The model was applied to nuclear research facilities in Brazil. • Some ‘safety culture’ weaknesses were detected in the assessed organization. • A potential tool to develop safety management programs in nuclear facilities. - Abstract: A safe and reliable operation of nuclear power plants depends not only on technical performance, but also on the people and on the organization. Organizational factors have been recognized as the main causal mechanisms of accidents by research organizations through USA, Europe and Japan. Deficiencies related with these factors reveal weaknesses in the organization’s safety culture. A significant number of instruments to assess the safety culture based on psychometric models that evaluate safety climate through questionnaires, and which are based on reliability and validity evidences, have been published in health and ‘safety at work’ areas. However, there are few safety culture assessment instruments with these characteristics (reliability and validity) available on nuclear literature. Therefore, this work proposes an instrument to evaluate, with valid and reliable measures, the safety climate of nuclear research facilities. The instrument was developed based on methodological principles applied to research modeling and its psychometric properties were evaluated by a reliability analysis and validation of content, face and construct. The instrument was applied to an important nuclear research organization in Brazil. This organization comprises 4 research reactors and many nuclear laboratories. The survey results made possible a demographic characterization and the identification of some possible safety culture weaknesses and pointing out potential areas to be improved in the assessed organization. Good evidence of reliability with Cronbach's alpha
Psychometric model for safety culture assessment in nuclear research facilities
Energy Technology Data Exchange (ETDEWEB)
Nascimento, C.S. do, E-mail: claudio.souza@ctmsp.mar.mil.br [Centro Tecnológico da Marinha em São Paulo (CTMSP), Av. Professor Lineu Prestes 2468, 05508-000 São Paulo, SP (Brazil); Andrade, D.A., E-mail: delvonei@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN – SP), Av. Professor Lineu Prestes 2242, 05508-000 São Paulo, SP (Brazil); Mesquita, R.N. de, E-mail: rnavarro@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN – SP), Av. Professor Lineu Prestes 2242, 05508-000 São Paulo, SP (Brazil)
2017-04-01
Highlights: • A psychometric model to evaluate ‘safety climate’ at nuclear research facilities. • The model presented evidences of good psychometric qualities. • The model was applied to nuclear research facilities in Brazil. • Some ‘safety culture’ weaknesses were detected in the assessed organization. • A potential tool to develop safety management programs in nuclear facilities. - Abstract: A safe and reliable operation of nuclear power plants depends not only on technical performance, but also on the people and on the organization. Organizational factors have been recognized as the main causal mechanisms of accidents by research organizations through USA, Europe and Japan. Deficiencies related with these factors reveal weaknesses in the organization’s safety culture. A significant number of instruments to assess the safety culture based on psychometric models that evaluate safety climate through questionnaires, and which are based on reliability and validity evidences, have been published in health and ‘safety at work’ areas. However, there are few safety culture assessment instruments with these characteristics (reliability and validity) available on nuclear literature. Therefore, this work proposes an instrument to evaluate, with valid and reliable measures, the safety climate of nuclear research facilities. The instrument was developed based on methodological principles applied to research modeling and its psychometric properties were evaluated by a reliability analysis and validation of content, face and construct. The instrument was applied to an important nuclear research organization in Brazil. This organization comprises 4 research reactors and many nuclear laboratories. The survey results made possible a demographic characterization and the identification of some possible safety culture weaknesses and pointing out potential areas to be improved in the assessed organization. Good evidence of reliability with Cronbach's alpha
Variance in binary stellar population synthesis
Breivik, Katelyn; Larson, Shane L.
2016-03-01
In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.
International Nuclear Information System (INIS)
Domanska, Urszula; Lachwa, Joanna
2005-01-01
The (solid + liquid) equilibrium (SLE) of eight binary systems containing N-methyl-2-pyrrolidinone (NMP) with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) were carried out by using a dynamic method from T = 200 K to the melting point of the NMP. The isothermal (vapour + liquid) equilibrium data (VLE) have been measured for three binary mixtures of NMP with 2-propanone, 3-pentanone and 2-hexanone at pressure range from p = 0 kPa to p = 115 kPa. Data were obtained at the temperature T = 333.15 K for the first system and at T = 373.15 K for the second two systems. The experimental results of SLE have been correlated using the binary parameters Wilson, UNIQUAC ASM and two modified NRTL equations. The root-mean-square deviations of the solubility temperatures for all the calculated values vary from (0.32 K to 0.68 K) and depend on the particular equation used. The data of VLE were correlated with one to three parameters in the Redlich-Kister expansion. Binary mixtures of NMP with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) have been investigated in the framework of the modified UNIFAC (Do) model. The reported new interaction parameters for NMP-group (c-CONCH 3 ) and carbonyl group ( C=O) let the model consistently described a set of thermodynamic properties, including (solid + liquid) equilibrium (vapour + liquid) equilibrium, excess Gibbs energy and molar excess enthalpies of mixing. Our experimental and literature data of binary mixtures containing NMP and ketones were compared with the results of prediction with the modified UNIFAC (Do) model
Development of an integrated cost model for nuclear plant decommissioning
International Nuclear Information System (INIS)
Amos, G.; Roy, R.
2003-01-01
A need for an integrated cost estimating tool for nuclear decommissioning and associated waste processing and storage facilities for Intermediate Level Waste (ILW) was defined during the authors recent MSc studies. In order to close the defined gap a prototype tool was developed using logically derived CER's and cost driver variables. The challenge in developing this was to be able to produce a model that could produce realistic cost estimates from the limited levels of historic cost data that was available for analysis. The model is an excel based tool supported by 3 point risk estimating output and is suitable for producing estimates for strategic or optional cost estimates (±30%) early in the conceptual stage of a decommissioning project. The model was validated using minimal numbers of case studies supported by expert opinion discussion. The model provides an enhanced approach for integrated decommissioning estimates which will be produced concurrently with strategic options analysis on a nuclear site
Quantummechanical multi-step direct models for nuclear data applications
International Nuclear Information System (INIS)
Koning, A.J.
1992-10-01
Various multi-step direct models have been derived and compared on a theoretical level. Subsequently, these models have been implemented in the computer code system KAPSIES, enabling a consistent comparison on the basis of the same set of nuclear parameters and same set of numerical techniques. Continuum cross sections in the energy region between 10 and several hundreds of MeV have successfully been analysed. Both angular distributions and energy spectra can be predicted in an essentially parameter-free manner. It is demonstrated that the quantum-mechanical MSD models (in particular the FKK model) give an improved prediction of pre-equilibrium angular distributions as compared to the experiment-based systematics of Kalbach. This makes KAPSIES a reliable tool for nuclear data applications in the afore-mentioned energy region. (author). 10 refs., 2 figs
Summary of Numerical Modeling for Underground Nuclear Test Monitoring Symposium
International Nuclear Information System (INIS)
Taylor, S.R.; Kamm, J.R.
1993-01-01
This document contains the Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium held in Durango, Colorado on March 23-25, 1993. The symposium was sponsored by the Office of Arms Control and Nonproliferation of the United States Department of Energy and hosted by the Source Region Program of Los Alamos National Laboratory. The purpose of the meeting was to discuss state-of-the-art advances in numerical simulations of nuclear explosion phenomenology for the purpose of test ban monitoring. Another goal of the symposium was to promote discussion between seismologists and explosion source-code calculators. Presentation topics include the following: numerical model fits to data, measurement and characterization of material response models, applications of modeling to monitoring problems, explosion source phenomenology, numerical simulations and seismic sources
A study on the hierarchy model of nuclear reactions
International Nuclear Information System (INIS)
Kitazoe, Yasuhiro; Sekiya, Tamotsu
1975-01-01
The application of the hierarchy model of nuclear reaction is discussed, and the hierarchy model means that the compound nucleus state is formed after several steps, at least, one step of reaction. This model was applied to the analysis of the observed cross sections of 235 U and some other elements. Neglecting exchange scattering effect, the equations for the total neutron cross section of 235 U were obtained. One of these equations describes explicitly the hierarchy of the transition from intermediate reaction state Xm into the compound nucleus state Xs, and another one describes the cross section averaged over an energy interval larger than the average level spacing of compound nucleus eigenvalues. The hierarchy of reaction mechanism was investigated in more detail, and the hierarchy model was applied to the case of unresolved energy region. It was not tried to evaluate the strength function in the mass region (A>140), since the effect of nuclear deformation was neglected in the task. (Iwase, T.)
Thermohydraulic modeling of nuclear thermal rockets: The KLAXON code
International Nuclear Information System (INIS)
Hall, M.L.; Rider, W.J.; Cappiello, M.W.
1992-01-01
The hydrogen flow from the storage tanks, through the reactor core, and out the nozzle of a Nuclear Thermal Rocket is an integral design consideration. To provide an analysis and design tool for this phenomenon, the KLAXON code is being developed. A shock-capturing numerical methodology is used to model the gas flow (the Harten, Lax, and van Leer method, as implemented by Einfeldt). Preliminary results of modeling the flow through the reactor core and nozzle are given in this paper
On some recent developments in microscopic nuclear models
International Nuclear Information System (INIS)
Piepenbring, R.
1987-01-01
An overview of the status of development of some microscopic nuclear models is presented. A special attention is paid to the recent calculations starting from the effective nucleon-nucleon force, to the angular momentum projection method before variation, to the multiphonon method and to the selfconsistent coordinate method. The success and the limitations of the three last mentioned models are illustrated in the example of 168 Er
MMSNF 2005. Materials models and simulations for nuclear fuels
Energy Technology Data Exchange (ETDEWEB)
Freyss, M.; Durinck, J.; Carlot, G.; Sabathier, C.; Martin, P.; Garcia, P.; Ripert, M.; Blanpain, P.; Lippens, M.; Schut, H.; Federov, A.V.; Bakker, K.; Osaka, M.; Miwa, S.; Sato, I.; Tanaka, K.; Kurosaki, K.; Uno, M.; Yamanaka, S.; Govers, K.; Verwerft, M.; Hou, M.; Lemehov, S.E.; Terentyev, D.; Govers, K.; Kotomin, E.A.; Ashley, N.J.; Grimes, R.W.; Van Uffelen, P.; Mastrikov, Y.; Zhukovskii, Y.; Rondinella, V.V.; Kurosaki, K.; Uno, M.; Yamanaka, S.; Minato, K.; Phillpot, S.; Watanabe, T.; Shukla, P.; Sinnott, S.; Nino, J.; Grimes, R.; Staicu, D.; Hiernaut, J.P.; Wiss, T.; Rondinella, V.V.; Ronchi, C.; Yakub, E.; Kaye, M.H.; Morrison, C.; Higgs, J.D.; Akbari, F.; Lewis, B.J.; Thompson, W.T.; Gueneau, C.; Gosse, S.; Chatain, S.; Dumas, J.C.; Sundman, B.; Dupin, N.; Konings, R.; Noel, H.; Veshchunov, M.; Dubourg, R.; Ozrin, C.V.; Veshchunov, M.S.; Welland, M.T.; Blanc, V.; Michel, B.; Ricaud, J.M.; Calabrese, R.; Vettraino, F.; Tverberg, T.; Kissane, M.; Tulenko, J.; Stan, M.; Ramirez, J.C.; Cristea, P.; Rachid, J.; Kotomin, E.; Ciriello, A.; Rondinella, V.V.; Staicu, D.; Wiss, T.; Konings, R.; Somers, J.; Killeen, J
2006-07-01
The MMSNF Workshop series aims at stimulating research and discussions on models and simulations of nuclear fuels and coupling the results into fuel performance codes.This edition was focused on materials science and engineering for fuel performance codes. The presentations were grouped in three technical sessions: fundamental modelling of fuel properties; integral fuel performance codes and their validation; collaborations and integration of activities. (A.L.B.)
MMSNF 2005. Materials models and simulations for nuclear fuels
International Nuclear Information System (INIS)
Freyss, M.; Durinck, J.; Carlot, G.; Sabathier, C.; Martin, P.; Garcia, P.; Ripert, M.; Blanpain, P.; Lippens, M.; Schut, H.; Federov, A.V.; Bakker, K.; Osaka, M.; Miwa, S.; Sato, I.; Tanaka, K.; Kurosaki, K.; Uno, M.; Yamanaka, S.; Govers, K.; Verwerft, M.; Hou, M.; Lemehov, S.E.; Terentyev, D.; Govers, K.; Kotomin, E.A.; Ashley, N.J.; Grimes, R.W.; Van Uffelen, P.; Mastrikov, Y.; Zhukovskii, Y.; Rondinella, V.V.; Kurosaki, K.; Uno, M.; Yamanaka, S.; Minato, K.; Phillpot, S.; Watanabe, T.; Shukla, P.; Sinnott, S.; Nino, J.; Grimes, R.; Staicu, D.; Hiernaut, J.P.; Wiss, T.; Rondinella, V.V.; Ronchi, C.; Yakub, E.; Kaye, M.H.; Morrison, C.; Higgs, J.D.; Akbari, F.; Lewis, B.J.; Thompson, W.T.; Gueneau, C.; Gosse, S.; Chatain, S.; Dumas, J.C.; Sundman, B.; Dupin, N.; Konings, R.; Noel, H.; Veshchunov, M.; Dubourg, R.; Ozrin, C.V.; Veshchunov, M.S.; Welland, M.T.; Blanc, V.; Michel, B.; Ricaud, J.M.; Calabrese, R.; Vettraino, F.; Tverberg, T.; Kissane, M.; Tulenko, J.; Stan, M.; Ramirez, J.C.; Cristea, P.; Rachid, J.; Kotomin, E.; Ciriello, A.; Rondinella, V.V.; Staicu, D.; Wiss, T.; Konings, R.; Somers, J.; Killeen, J.
2006-01-01
The MMSNF Workshop series aims at stimulating research and discussions on models and simulations of nuclear fuels and coupling the results into fuel performance codes.This edition was focused on materials science and engineering for fuel performance codes. The presentations were grouped in three technical sessions: fundamental modelling of fuel properties; integral fuel performance codes and their validation; collaborations and integration of activities. (A.L.B.)
Soliton matter as a model of dense nuclear matter
International Nuclear Information System (INIS)
Glendenning, N.K.
1985-01-01
We employ the hybrid soliton model of the nucleon consisting of a topological meson field and deeply bound quarks to investigate the behavior of the quarks in soliton matter as a function of density. To organize the calculation, we place the solitons on a spatial lattice. The model suggests the transition of matter from a color insulator to a color conductor above a critical density of a few times normal nuclear density. 9 references, 5 figures
Methodology and preliminary models for analyzing nuclear safeguards decisions
International Nuclear Information System (INIS)
1978-11-01
This report describes a general analytical tool designed to assist the NRC in making nuclear safeguards decisions. The approach is based on decision analysis--a quantitative procedure for making decisions under uncertain conditions. The report: describes illustrative models that quantify the probability and consequences of diverted special nuclear material and the costs of safeguarding the material, demonstrates a methodology for using this information to set safeguards regulations (safeguards criteria), and summarizes insights gained in a very preliminary assessment of a hypothetical reprocessing plant
Nuclear security culture: a generic model for universal application
International Nuclear Information System (INIS)
Khripunov, I.
2005-01-01
Full text: Nuclear security culture found its way into professional parlance several years ago, but still lacks an agreed-upon definition and description. The February 2005 U.S.-Russian Joint Statement, issued at the presidential summit meeting in Bratislava, referred specifically to security culture, focusing renewed attention on the concept. Numerous speakers at the March 2005 International Atomic Energy Agency's (IAEA) international conference on nuclear security referred to security culture, but their visions and interpretations were often at odds with one another. Clearly, there is a need for a generic model of nuclear security culture with universal applicability. Internationally acceptable standards in this area would be invaluable for evaluation, comparison, cooperation, and assistance. They would also help international bodies better manage their relations with the nuclear sectors in various countries. This paper will develop such a model. It will use the IAEA definition of nuclear security, and then apply Edgar Schein's model of organizational culture to security culture at a generic nuclear facility. A cultural approach to physical protection involves determining what attitudes and beliefs need to be established in an organization, how these attitudes and beliefs manifest themselves in the behavior of assigned personnel, and how desirable attitudes and beliefs can be transcribed into formal working methods to produce good outcomes, i.e., effective protection. The security-culture mechanism I will propose is broken into four major units: facility leadership, proactive policies and procedures, personnel performance, and learning and professional improvement. The paper will amplify on the specific traits characteristic of each of these units. Security culture is not a panacea. In a time of mounting terrorist threats, it should nonetheless be looked upon as a necessary organizational tool that enhances the skills of nuclear personnel and ensures that
Three-Body Nuclear Forces from a Matrix Model
Hashimoto, Koji
2010-01-01
We compute three-body nuclear forces at short distances by using the nuclear matrix model of holographic QCD proposed in our previous paper with P. Yi. We find that the three-body forces at short distances are repulsive for (a) aligned three neutrons with averaged spins, and (b) aligned proton-proton-neutron / proton-neutron-neutron. These indicate that in dense states of neutrons such as cores of neutron stars, or in Helium-3 / tritium nucleus, the repulsive forces are larger than the ones estimated from two-body forces only.
Energy Technology Data Exchange (ETDEWEB)
Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)
2011-05-15
Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.
INTEGRATION OF FACILITY MODELING CAPABILITIES FOR NUCLEAR NONPROLIFERATION ANALYSIS
Energy Technology Data Exchange (ETDEWEB)
Gorensek, M.; Hamm, L.; Garcia, H.; Burr, T.; Coles, G.; Edmunds, T.; Garrett, A.; Krebs, J.; Kress, R.; Lamberti, V.; Schoenwald, D.; Tzanos, C.; Ward, R.
2011-07-18
Developing automated methods for data collection and analysis that can facilitate nuclear nonproliferation assessment is an important research area with significant consequences for the effective global deployment of nuclear energy. Facility modeling that can integrate and interpret observations collected from monitored facilities in order to ascertain their functional details will be a critical element of these methods. Although improvements are continually sought, existing facility modeling tools can characterize all aspects of reactor operations and the majority of nuclear fuel cycle processing steps, and include algorithms for data processing and interpretation. Assessing nonproliferation status is challenging because observations can come from many sources, including local and remote sensors that monitor facility operations, as well as open sources that provide specific business information about the monitored facilities, and can be of many different types. Although many current facility models are capable of analyzing large amounts of information, they have not been integrated in an analyst-friendly manner. This paper addresses some of these facility modeling capabilities and illustrates how they could be integrated and utilized for nonproliferation analysis. The inverse problem of inferring facility conditions based on collected observations is described, along with a proposed architecture and computer framework for utilizing facility modeling tools. After considering a representative sampling of key facility modeling capabilities, the proposed integration framework is illustrated with several examples.
Integration of facility modeling capabilities for nuclear nonproliferation analysis
International Nuclear Information System (INIS)
Garcia, Humberto; Burr, Tom; Coles, Garill A.; Edmunds, Thomas A.; Garrett, Alfred; Gorensek, Maximilian; Hamm, Luther; Krebs, John; Kress, Reid L.; Lamberti, Vincent; Schoenwald, David; Tzanos, Constantine P.; Ward, Richard C.
2012-01-01
Developing automated methods for data collection and analysis that can facilitate nuclear nonproliferation assessment is an important research area with significant consequences for the effective global deployment of nuclear energy. Facility modeling that can integrate and interpret observations collected from monitored facilities in order to ascertain their functional details will be a critical element of these methods. Although improvements are continually sought, existing facility modeling tools can characterize all aspects of reactor operations and the majority of nuclear fuel cycle processing steps, and include algorithms for data processing and interpretation. Assessing nonproliferation status is challenging because observations can come from many sources, including local and remote sensors that monitor facility operations, as well as open sources that provide specific business information about the monitored facilities, and can be of many different types. Although many current facility models are capable of analyzing large amounts of information, they have not been integrated in an analyst-friendly manner. This paper addresses some of these facility modeling capabilities and illustrates how they could be integrated and utilized for nonproliferation analysis. The inverse problem of inferring facility conditions based on collected observations is described, along with a proposed architecture and computer framework for utilizing facility modeling tools. After considering a representative sampling of key facility modeling capabilities, the proposed integration framework is illustrated with several examples.
Integration Of Facility Modeling Capabilities For Nuclear Nonproliferation Analysis
International Nuclear Information System (INIS)
Gorensek, M.; Hamm, L.; Garcia, H.; Burr, T.; Coles, G.; Edmunds, T.; Garrett, A.; Krebs, J.; Kress, R.; Lamberti, V.; Schoenwald, D.; Tzanos, C.; Ward, R.
2011-01-01
Developing automated methods for data collection and analysis that can facilitate nuclear nonproliferation assessment is an important research area with significant consequences for the effective global deployment of nuclear energy. Facility modeling that can integrate and interpret observations collected from monitored facilities in order to ascertain their functional details will be a critical element of these methods. Although improvements are continually sought, existing facility modeling tools can characterize all aspects of reactor operations and the majority of nuclear fuel cycle processing steps, and include algorithms for data processing and interpretation. Assessing nonproliferation status is challenging because observations can come from many sources, including local and remote sensors that monitor facility operations, as well as open sources that provide specific business information about the monitored facilities, and can be of many different types. Although many current facility models are capable of analyzing large amounts of information, they have not been integrated in an analyst-friendly manner. This paper addresses some of these facility modeling capabilities and illustrates how they could be integrated and utilized for nonproliferation analysis. The inverse problem of inferring facility conditions based on collected observations is described, along with a proposed architecture and computer framework for utilizing facility modeling tools. After considering a representative sampling of key facility modeling capabilities, the proposed integration framework is illustrated with several examples.
Role of conceptual models in nuclear power plant operation
International Nuclear Information System (INIS)
Williams, M.D.; Moran, T.P.; Brown, J.S.
1982-01-01
A crucial objective in plant operation (and perhaps licensing) ought to be to explicitly train operators to develop, perhaps with computer aids, robust conceptual models of the plants they control. The question is whether we are actually able to develop robust conceptual models and validate their robustness. Cognitive science is just beginning to come to grips with this problem. This paper describes some of the evolving technology for building conceptual models of physical mechanisms and some of the implications of such models in the context of nuclear power plant operation
Nuclear spectroscopy in large shell model spaces: recent advances
International Nuclear Information System (INIS)
Kota, V.K.B.
1995-01-01
Three different approaches are now available for carrying out nuclear spectroscopy studies in large shell model spaces and they are: (i) the conventional shell model diagonalization approach but taking into account new advances in computer technology; (ii) the recently introduced Monte Carlo method for the shell model; (iii) the spectral averaging theory, based on central limit theorems, in indefinitely large shell model spaces. The various principles, recent applications and possibilities of these three methods are described and the similarity between the Monte Carlo method and the spectral averaging theory is emphasized. (author). 28 refs., 1 fig., 5 tabs
Cash flow forecasting model for nuclear power projects
International Nuclear Information System (INIS)
Liu Wei; Guo Jilin
2002-01-01
Cash flow forecasting is very important for owners and contractors of nuclear power projects to arrange the capital and to decrease the capital cost. The factors related to contractor cash flow forecasting are analyzed and a cash flow forecasting model is presented which is suitable for both contractors and owners. The model is efficiently solved using a cost-schedule data integration scheme described. A program is developed based on the model and verified with real project data. The result indicates that the model is efficient and effective
K- nuclear potentials from in-medium chirally motivated models
International Nuclear Information System (INIS)
Cieply, A.; Gazda, D.; Mares, J.; Friedman, E.; Gal, A.
2011-01-01
A self-consistent scheme for constructing K - nuclear optical potentials from subthreshold in-medium KN s-wave scattering amplitudes is presented and applied to analysis of kaonic atoms data and to calculations of K - quasibound nuclear states. The amplitudes are taken from a chirally motivated meson-baryon coupled-channel model, both at the Tomozawa-Weinberg leading order and at the next to leading order. Typical kaonic atoms potentials are characterized by a real part -Re V K - chiral =85±5 MeV at nuclear matter density, in contrast to half this depth obtained in some derivations based on in-medium KN threshold amplitudes. The moderate agreement with data is much improved by adding complex ρ- and ρ 2 -dependent phenomenological terms, found to be dominated by ρ 2 contributions that could represent KNN→YN absorption and dispersion, outside the scope of meson-baryon chiral models. Depths of the real potentials are then near 180 MeV. The effects of p-wave interactions are studied and found secondary to those of the dominant s-wave contributions. The in-medium dynamics of the coupled-channel model is discussed and systematic studies of K - quasibound nuclear states are presented.
Penetration Testing Model for Web sites Hosted in Nuclear Malaysia
International Nuclear Information System (INIS)
Mohd Dzul Aiman Aslan; Mohamad Safuan Sulaiman; Siti Nurbahyah Hamdan; Saaidi Ismail; Mohd Fauzi Haris; Norzalina Nasiruddin; Raja Murzaferi Mokhtar
2012-01-01
Nuclear Malaysia web sites has been very crucial in providing important and useful information and services to the clients as well as the users worldwide. Furthermore, a web site is important as it reflects the organisation image. To ensure the integrity of the content of web site, a study has been made and a penetration testing model has been implemented to test the security of several web sites hosted at Nuclear Malaysia for malicious attempts. This study will explain how the security was tested in the detailed condition and measured. The result determined the security level and the vulnerability of several web sites. This result is important for improving and hardening the security of web sites in Nuclear Malaysia. (author)
International Nuclear Information System (INIS)
Lin, Yanhui
2016-01-01
Components of nuclear safety systems are in general highly reliable, which leads to a difficulty in modeling their degradation and failure behaviors due to the limited amount of data available. Besides, the complexity of such modeling task is increased by the fact that these systems are often subject to multiple competing degradation processes and that these can be dependent under certain circumstances, and influenced by a number of external factors (e.g. temperature, stress, mechanical shocks, etc.). In this complicated problem setting, this PhD work aims to develop a holistic framework of models and computational methods for the reliability-based analysis and maintenance optimization of nuclear safety systems taking into account the available knowledge on the systems, degradation and failure behaviors, their dependencies, the external influencing factors and the associated uncertainties.The original scientific contributions of the work are: (1) For single components, we integrate random shocks into multi-state physics models for component reliability analysis, considering general dependencies between the degradation and two types of random shocks. (2) For multi-component systems (with a limited number of components):(a) a piecewise-deterministic Markov process modeling framework is developed to treat degradation dependency in a system whose degradation processes are modeled by physics-based models and multi-state models; (b) epistemic uncertainty due to incomplete or imprecise knowledge is considered and a finite-volume scheme is extended to assess the (fuzzy) system reliability; (c) the mean absolute deviation importance measures are extended for components with multiple dependent competing degradation processes and subject to maintenance; (d) the optimal maintenance policy considering epistemic uncertainty and degradation dependency is derived by combining finite-volume scheme, differential evolution and non-dominated sorting differential evolution; (e) the
Teiji, KUNIHIRO; Tatsuyuki, TAKATSUKA; Ryozo, TAMAGAKI; Department of National Sciences, Ryukoku University; College of Humanities and Social Sciences, Iwate University; Department of Physics, Kyoto University
1985-01-01
Pion condensation in the symmetric nuclear matter is investigated on the basis of the ALS (alternating-layer-spin) model which provides a good description for the π^0 condensation. We perform energy calculations in a realistic way where the isobar (Δ)-mixing, the short range effects and the exchange energy of the interaction are taken into account. The Δ-mixing effect is built in the model state as previously done in the neutron matter. We preferentially employ G-0 force of Sprung and Banerje...
Validation of nuclear models used in space radiation shielding applications
International Nuclear Information System (INIS)
Norman, Ryan B.; Blattnig, Steve R.
2013-01-01
A program of verification and validation has been undertaken to assess the applicability of models to space radiation shielding applications and to track progress as these models are developed over time. In this work, simple validation metrics applicable to testing both model accuracy and consistency with experimental data are developed. The developed metrics treat experimental measurement uncertainty as an interval and are therefore applicable to cases in which epistemic uncertainty dominates the experimental data. To demonstrate the applicability of the metrics, nuclear physics models used by NASA for space radiation shielding applications are compared to an experimental database consisting of over 3600 experimental cross sections. A cumulative uncertainty metric is applied to the question of overall model accuracy, while a metric based on the median uncertainty is used to analyze the models from the perspective of model development by examining subsets of the model parameter space.
Semantic Technologies for Nuclear Knowledge Modelling and Applications
International Nuclear Information System (INIS)
Beraha, D.; Gladyshev, M.
2016-01-01
Full text: The IAEA has been engaged in working with Member States to preserve and enhance nuclear knowledge, and in supporting wide dissemination of safety related technical and technological information enhancing nuclear safety. The knowledge organization systems (ontologies, taxonomies, thesauri, etc.) provide one of the means to model and structure a given knowledge domain. The significance of knowledge organization systems (KOS) has been greatly enhanced by the evolution of the semantic technologies, enabling machines to “understand” the concepts described in a KOS, and to use them in a variety of applications. Over recent years semantic technologies have emerged as efficient means to improve access to information and knowledge. The Semantic Web Standards play an important role in creating an infrastructure of interoperable data sources based on principles of Linked Data. The status of utilizing semantic technologies in the nuclear domain is shortly reviewed, noting that such technologies are in their early stage of adoption, and considering some aspects which are specific to nuclear knowledge management. Several areas are described where semantic technologies are already deployed, and other areas are indicated where applications based on semantic technologies will have a strong impact on nuclear knowledge management in the near future. (author
Finite element modeling of AP1000 nuclear island
International Nuclear Information System (INIS)
Tinic, S.; Orr, R.
2003-01-01
The AP1000 is a standard design developed by Westinghouse and its partners for an advanced nuclear power plant utilizing passive safety features. It is based on the certified design of the AP600 and has been uprated to 1000 MWe. The plant has five principal building structures; the nuclear island, the turbine building; the annex building; the diesel generator building and the radwaste building. The nuclear island consists of the containment building (the steel containment vessel and the containment internal structures), the shield building, and the auxiliary building. These structures are founded on a common basemat and are collectively known as the nuclear island. This paper describes use of the general purpose finite element program ANSYS [2] in structural analyses and qualification of the AP1000 nuclear island buildings. It describes the modeling of the shield building and the auxiliary building and the series of analyses and the flow of information from the global analyses to the detailed analyses and building qualification. (author)
The appliance of graphics modeling in nuclear plant information system
International Nuclear Information System (INIS)
Bai Zhe; Li Guofang
2010-01-01
The nuclear plants contain a lot of sub-system, such as operation management, manufacture system, inventory system, human resource system and so forth. The standardized data graphics modeling technology can ensure the data interaction, compress the design cycle, avoid the replicated design, ensure the data integrity and consistent. The standardized data format which is on the basis of STEP standard and complied with XML is competent tool in different sub-system of nuclear plants. In order to meet this demand, a data graphics modeling standard is proposed. It is shown the relationship between systems, in system, between data by the standard. The graphic modeling effectively improves the performance between systems, designers, engineers, operations, supports department. It also provides the reliable and available data source for data mining and business intelligence. (authors)
Atomic scale modelling of materials of the nuclear fuel cycle
International Nuclear Information System (INIS)
Bertolus, M.
2011-10-01
This document written to obtain the French accreditation to supervise research presents the research I conducted at CEA Cadarache since 1999 on the atomic scale modelling of non-metallic materials involved in the nuclear fuel cycle: host materials for radionuclides from nuclear waste (apatites), fuel (in particular uranium dioxide) and ceramic cladding materials (silicon carbide). These are complex materials at the frontier of modelling capabilities since they contain heavy elements (rare earths or actinides), exhibit complex structures or chemical compositions and/or are subjected to irradiation effects: creation of point defects and fission products, amorphization. The objective of my studies is to bring further insight into the physics and chemistry of the elementary processes involved using atomic scale modelling and its coupling with higher scale models and experimental studies. This work is organised in two parts: on the one hand the development, adaptation and implementation of atomic scale modelling methods and validation of the approximations used; on the other hand the application of these methods to the investigation of nuclear materials under irradiation. This document contains a synthesis of the studies performed, orientations for future research, a detailed resume and a list of publications and communications. (author)
Model for the determination of the nuclear fuel
International Nuclear Information System (INIS)
Azevedo, J.B.L. de.
1979-09-01
The Nuclear Fuel Cost Determination Model, MDCN, is a computer program written in FORTRAN IV, meant to calculate the nuclear fuel cost employed in nuclear power plants for heat or electrical energy generation. The economic principles employed are: capital recovery proportional to the energy generation, present worth method for the equivalence of costs and levelized fuel cost calculation. This model presents some inovations in comparasion with other models already in use, since it takes into account refueling and maintenance outages and it does not fix the fuel cycle steps (industrial processes and services). The first inovation leads to a more realistic cost determination and permits the model to be employed together with hydrothermal power system simulators; the second permits a more flexible use of the model, like economical comparison of fuel cycles. Complementing the main body of the work, where the theoretical fundamentals and methodology necessary to the calculation developments are discussed, annexes are included treating in greater detail some specific itens; the more important ones refer to the FORTRAN program, input data preparation and example. (Author) [pt