scholarly journals NADA-FLD: a general relativistic, multidimensional neutrino-hydrodynamics code employing flux-limited diffusion

2019 ◽  
Vol 490 (3) ◽  
pp. 3545-3572 ◽  
Author(s):  
N Rahman ◽  
O Just ◽  
H-T Janka
Keyword(s):  
Operator Splitting ◽  
Lateral Diffusion ◽  
Neutrino Energy ◽  
Two Dimensions ◽  
Polar Coordinates ◽  
General Relativistic ◽  
Energy Dependent ◽  
Main Effects ◽  
Limited Diffusion ◽  
Good Agreement

ABSTRACT We present the new code NADA-FLD to solve multidimensional neutrino-hydrodynamics in full general relativity (GR) in spherical polar coordinates. The energy-dependent neutrino transport assumes the flux-limited diffusion approximation and evolves the neutrino energy densities measured in the frame comoving with the fluid. Operator splitting is used to avoid multidimensional coupling of grid cells in implicit integration steps involving matrix inversions. Terms describing lateral diffusion and advection are integrated explicitly using the Allen–Cheng or the Runge–Kutta–Legendre method, which remain stable even in the optically thin regime. We discuss several toy-model problems in one and two dimensions to test the basic functionality and individual components of the transport scheme. We also perform fully dynamic core-collapse supernova (CCSN) simulations in spherical symmetry. For a Newtonian model, we find good agreement with the M1 code ALCAR, and for a GR model, we reproduce the main effects of GR in CCSNe already found by previous works.

scholarly journals Deconvolution in Measurements of Muon Neutrino Energy Spectra with IceCube

2019 ◽  
Vol 207 ◽  
pp. 05006
Author(s):  
Tim Ruhe
Keyword(s):  
Neutrino Energy ◽  
Neutrino Telescope ◽  
Muon Neutrino ◽  
Energy Spectra ◽  
Spectral Measurements ◽  
Energy Dependent

As the energy of an incident neutrino cannot be accessed experimentally, muon neutrino energy spectra have to be inferred from energy-dependent observables, using deconvolution algorithms. This paper discusses the challenges associated with the application of deconvolution algorithms and presents two examples of spectral measurements obtained using the IceCube neutrino telescope in the 59- and 79-string configuration.

Does Wrongdoer Reputation Matter? Impact of Auditor-Wrongdoer Performance and Likeability Reputations on Fellow Auditors' Intention to Take Action and Choice of Reporting Outlet

2011 ◽  
Vol 23 (2) ◽  
pp. 207-234 ◽  
Author(s):  
Jesse C. Robertson ◽  
Chad M. Stefaniak ◽  
Mary B. Curtis
Keyword(s):  
Two Dimensions ◽  
Data Availability ◽  
Good Performer ◽  
Reporting Decisions ◽  
Prior Literature ◽  
Reporting Channel ◽  
Channel Preferences ◽  
Main Effects ◽  
The Impact ◽  
Selection Of

ABSTRACT We investigate the effects of auditor-wrongdoer reputations for performance and likeability on fellow auditors' intentions to take action in response to a questionable audit act. We also use this context to explore auditor selection of reporting outlets, when they do choose to take action. In an experiment with 181 auditors, main effects suggest that likeability reputation is a significant determinant of intention to take action, while performance reputation is marginally significant. As expected, interaction results indicate that auditors have the greatest intention to take action against less likeable, poor performers. Contrary to expectations, intention to take action against a more likeable, good performer is no lower than the mixed conditions. Thus, the influence of the two dimensions of reputation is complex. Additionally, we find auditors are more likely to whistle-blow internally than externally, and through non-anonymous outlets than anonymous outlets. Our contributions include exploring the impact of reputation on the actions of third parties, and advancing prior literature by considering the influence of wrongdoer attributes on reporting decisions and auditors' reporting channel preferences. Data Availability: Data are available from the first author upon request.

scholarly journals Variation in rms charge radii of deuteron and helium nuclei with s\sqrt s

Nukleonika ◽  
2020 ◽  
Vol 65 (4) ◽  
pp. 211-215
Author(s):  
Sarwat Zahra ◽  
Bushra Shafaq ◽  
Bushra Kanwal ◽  
Nosheen Akbar
Keyword(s):  
Center Of Mass ◽  
Form Factors ◽  
Mass Energy ◽  
Charge Radii ◽  
Center Of Mass Energy ◽  
Theoretical Predictions ◽  
Dependent Form ◽  
Energy Dependent ◽  
The Relationship ◽  
Good Agreement

AbstractBy considering energy-dependent form factors extracted from generalized Chou–Yang model, root mean square (rms) charge radii of deuteron and helium nuclei (alpha) are predicted at different values of center of mass energy which are in good agreement with theoretical predictions and experimental results. The rms radius is inversely proportional to mass of nuclei. Besides, the relationship between radii and energy are also derived.

The Effects of Not-for-Profit Hospital Reported Profits and Charitable Care on Perceptions of Tax-Exempt Status

2001 ◽  
Vol 23 (2) ◽  
pp. 50-58 ◽  
Author(s):  
Kathryn J. Jervis Wilkicki
Keyword(s):  
Local Property ◽  
Two Dimensions ◽  
Accounting Firms ◽  
For Profit ◽  
Not For Profit ◽  
Tax Practitioners ◽  
State Income Tax ◽  
Tax Exempt ◽  
State Income ◽  
Main Effects

I investigate whether the hospital tax-exemption decision is a function of (1) reported profits and (2) the amount of charitable care provided. Tax practitioners from public accounting firms made decisions about whether the hospital should maintain federal and state income tax and local property tax exemptions. A between-subject design was used with cases at two dimensions: reported profits (high and low) and level of charitable care (high and low). Findings revealed that the main effects of reported profits and charitable care do not independently appear to affect respondents' perceptions about tax exemption. However, when charitable care is low, respondents' perceptions about tax exemption were negatively influenced by high reported profits.

scholarly journals Dynamics of Type-II Supernovae

1996 ◽  
Vol 145 ◽  
pp. 109-117 ◽  
Author(s):  
H.-Th. Janka ◽  
E. M. Müller
Keyword(s):  
Large Scale ◽  
Energy Deposition ◽  
Supernova Explosion ◽  
Threshold Value ◽  
Neutrino Energy ◽  
Two Dimensions ◽  
Iron Core ◽  
Type Ii ◽  
Convective Processes ◽  
Hydrodynamical Simulations

Hydrodynamical simulations of type-II supernovae in one and two dimensions are performed for the revival phase of the delayed shock by neutrino energy deposition. Starting with a post-collapse model of the 1.31 Mʘ iron core of a 15 Mʘ star immediately after the stagnation of the prompt shock about 10 ms after core bounce, the models are followed for several hundred milliseconds with varied neutrino fluxes from the neutrino sphere. The variation of the neutrino luminosities is motivated by the considerable increase of the neutrino emission due to convective processes inside and close to the neutrino sphere (see Janka 1993), which are driven by negative gradients of entropy and electron concentration left behind by the prompt shock (Burrows & Fryxell 1992, Janka & Müller 1992). The size of this luminosity increase remains to be quantitatively analyzed yet and may require multi-dimensional neutrino transport. However, in the presented simulations the region below the neutrino sphere is cut out and replaced by an inner boundary condition, so that the convective zone is only partially included and the neutrino flows are treated as a freely changeable energy source.For small neutrino luminosities the energy transfer to the matter is insufficient to revive the stalled shock. However, there is a sharp transition to successful explosions, when the neutrino luminosities lie above some ‘threshold value’. Once the shock is driven out and the density and temperature of the matter between neutrino sphere and shock start to decrease during the expansion, suitable conditions for further neutrino energy deposition are maintained, and an explosion results. With the neutrino energy deposition the entropy per nucleon in the region between neutrino sphere and shock grows, and convective overturn will set in. Multi-dimensional simulations show that due to the large pressure scale height a large-scale pattern of up-flows and down-flows with velocities close to the local speed of sound develops. Consequently, cold, postshock material is advected down into the neutrino heating layer close to the neutrino sphere and hot material is transported outwards, thus reducing energy losses by re-emission of neutrinos and increasing the pressure behind the shock. Therefore these convective processes are found to be a very important aid to the delayed supernova explosion. In fact, two-dimensional models explode even in cases where spherically symmetrical computations fail.

Path integrals in polar coordinates

1969 ◽  
Vol 313 (1514) ◽  
pp. 445-452 ◽  
Keyword(s):  
Path Integrals ◽  
Free Particle ◽  
Two Dimensions ◽  
Polar Coordinates ◽  
Hamiltonian Approach

The problem of summation over Feynman histories in polar coordinates is discussed. Ordinary rules of calculus are used in conjunction with a Hamiltonian approach to the summation over histories. The procedure is checked by evaluating the propagator for a free particle in two dimensions.

Nanoscale Heat Transfer Modeling in Solids: Data Storage and Electronic Devices

2003 ◽  
Author(s):  
Sartaj S. Ghai ◽  
Myung S. Jhon ◽  
Cristina H. Amon ◽  
Yiao-Tee Hsia
Keyword(s):  
Heat Transfer ◽  
Data Storage ◽  
Electronic Devices ◽  
Internal Heat ◽  
Numerical Data ◽  
Computational Effort ◽  
Two Dimensions ◽  
Boltzmann Transport ◽  
Boltzmann Method ◽  
Good Agreement

Lattice Boltzmann method (LBM), is used to examine multi-length scale, confined heat conduction phenomena in solids for which sub-continuum regime is important. This paper describes the implementation of the method and its application to cases pertinent to data storage and electronic devices. Thin solid films with internal heat generation and with temperature difference across the boundaries are used as case studies to illustrate the benefits of the LBM. We compare our results with various hierarchical equations of heat transfer such as Fourier, Cattaneo, and Boltzmann transport equations, as well as with experimental and numerical data from the literature. Our results exhibit a good agreement with other methodologies in one and two dimensions, at a much lower computational effort.

Viscous flow over a cone at moderate incidence. Part 2. Supersonic boundary layer

1973 ◽  
Vol 59 (3) ◽  
pp. 593-620 ◽  
Author(s):  
T. C. Lin ◽  
S. G. Rubin
Keyword(s):  
Boundary Layer ◽  
Viscous Flow ◽  
Three Dimensional ◽  
Cross Flow ◽  
Lateral Diffusion ◽  
Supersonic Boundary Layer ◽  
Half Angle ◽  
Local Shear ◽  
Sharp Cone ◽  
Good Agreement

A finite-difference method recently developed to study three-dimensional viscous flow is applied here to the supersonic boundary layer on a sharp cone at moderate angles of incidence (α/θ [les ] 2, angle of attack α, cone half-angle θ). The present analysis differs from previous investigations of this region in that (i) boundary-layer similarity is not assumed, (ii) the system of governing equations incorporates lateral diffusion and centrifugal force effects, and (iii) an improved numerical scheme for three-dimensional viscous flows of the type considered here is used. Solutions are shown to be non-similar at the separation streamline with local shear-layer formation. Detailed flow structure, including surface heat transfer, boundary-layer profiles and thickness, and the formation of swirling pairwise symmetric vortices, associated with cross-flow separation, are obtained. Good agreement is obtained between the present theoretical results and the existing experimental data.

scholarly journals Modeling Electric Field and Potential Distribution of an Model of Insulator in Two Dimensions by the Finite Element Method

2018 ◽  
Vol 3 (1) ◽  
pp. 01
Author(s):  
Nassima M ziou ◽  
Hani Benguesmia ◽  
Hilal Rahali
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
Potential Distribution ◽  
Two Dimensions ◽  
Comsol Multiphysics ◽  
The Finite Element Method ◽  
Good Agreement ◽  
Element Method

The electrical effects can be written by two magnitudes the field and the electrostatic potential, for the determination of the distribution of the field and the electric potential along the leakage distance of the polluted insulator, the comsol multiphysics software based on the finite element method will be used. The objective of this paper is the modeling electric field and potential distribution in Two Dimensions by the Finite Element Method on a model of insulator simulating the 1512L outdoor insulator used by the Algerian company of electricity and gas (SONELGAZ). This model is under different conductivity, applied voltage, position of clean layer and width of clean layer. The computer simulations are carried out by using the COMSOL multiphysics software. This paper describes how Comsol Multiphysics have been used for modeling of the insulator using electrostatic 2D simulations in the AC/DC module. Numerical results showed a good agreement.

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