Oberflächenspannung und Thermodynamik des perfekten Gases

1970 ◽  
Vol 25 (8-9) ◽  
pp. 1190-1202 ◽  
Author(s):  
Eberhard Hilf
Keyword(s):  
Particle Density ◽  
Level Density ◽  
Thermodynamic System ◽  
Particle Energy ◽  
External Potential ◽  
Additional Contribution ◽  
Quantum Gas ◽  
Surface Phenomena ◽  
Perfect Gas ◽  
Thermodynamic Variable

Abstract A thermodynamic system of N Fermions or Bosons, bound by an external potential but with almost no additional contribution of the interaction energy between the particles to the binding of the system is called a bound perfect quantum gas. Its single particle energy level density ρ (ε) depends on the properties of the external potential. This is chosen to be zero inside and infinite outside a given arbitrary simple connected closed shape. Within the leptodermous assumption A N1/3 ≫ 1 then ρ (ε) can be written explicitly as a sum of three terms which are proportional to the volume, surface, curvature tension. Its thermodynamics is developed: 1) one thermodynamic variable can be eliminated, reducing the phase space dimensions; 2) the Gibbs - Duhem relation is disfigured only by surface - and curvature terms, stating that the system is still makroscopically homogenious except in the surface area, where e.g. the particle density falls down to zero smoothly; 3) the Landsberg-definition p · V = ⅔ U still holds, confirming that our microscopically defined system is macroscopically a perfect gas in the sense of Landsberg, despite the surface phenomena. In the appendix the advantages of an operatorlike shortwriting of the partial derivative notation are demonstrated.

Thermodynamics and geometrothermodynamics of Born–Infeld black holes with cosmological constant

2015 ◽  
Vol 24 (11) ◽  
pp. 1550092
Author(s):  
Hernando Quevedo ◽  
María N. Quevedo ◽  
Alberto Sánchez
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Cosmological Constant ◽  
Thermodynamic System ◽  
Physical Parameters ◽  
Spherically Symmetric ◽  
Transition Structure ◽  
Thermodynamic Variable ◽  
Thermodynamic Variables ◽  
Range Of Values

In this paper, we investigate a class of spherically symmetric Born–Infeld black holes which contains the mass, electric charge, Born–Infeld parameter and the cosmological constant as physical parameters. We show that for the mass to be an extensive thermodynamic variable, it is necessary to consider the cosmological constant and the Born–Infeld parameter as thermodynamic variables as well. We analyze the properties of such a thermodynamic system, explore the range of values where the system is thermodynamically well-defined, and the phase transition structure. In addition, we show that the equilibrium manifold in the context of geometrothermodynamics reproduces correctly the thermodynamic properties of this black hole class.

scholarly journals Solar cosmic rays during the extremely high ground level enhancement on 23 February 1956

2005 ◽  
Vol 23 (6) ◽  
pp. 2281-2291 ◽  
Author(s):  
A. Belov ◽  
E. Eroshenko ◽  
H. Mavromichalaki ◽  
C. Plainaki ◽  
V. Yanke
Keyword(s):  
Cosmic Rays ◽  
Particle Density ◽  
Cosmic Ray ◽  
Ground Level ◽  
Particle Energy ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Solar Particle ◽  
Small Width ◽  
Standard Design

Abstract. The 23 February 1956 ground level enhancement of the solar cosmic ray intensity (GLE05) is the most famous among the proton events observed since 1942. But we do not have a great deal of information on this event due to the absence of solar wind and interplanetary magnetic field measurements at that time. Furthermore, there were no X-Ray or gamma observations and the information on the associated flare is limited. Cosmic ray data was obtained exclusively by ground level detectors of small size and in some cases of a non-standard design. In the present work all available data from neutron monitors operating in 1956 were analyzed, in order to develop a model of the solar cosmic ray behavior during the event. The time-dependent characteristics of the cosmic ray energy spectrum, cosmic ray anisotropy, and differential and integral fluxes have been evaluated utilizing different isotropic and anisotropic models. It is shown that the most outstanding features of this proton enhancement were a narrow and extremely intense beam of ultra-relativistic particles arriving at Earth just after the onset and the unusually high maximum solar particle energy. However, the contribution of this beam to the overall solar particle density and fluency was not significant because of its very short duration and small width. Our estimate of the integral flux for particles with energies over 100 MeV places this event above all subsequent. Perhaps the number of accelerated low energy particles was closer to a record value, but these particles passed mainly to the west of Earth. Many features of this GLE are apparently explained by the peculiarity of the particle interplanetary propagation from a remote (near the limb) source. The quality of the available neutron monitor data does not allow us to be certain of some details; these may be cleared up by the incorporation into the analysis of data from muonic telescopes and ionization chambers operating at that time. Keywords. Interplanatary physics (Cosmic rays; Energetic particles) – Solar physics, astrophysics and astronomy (Flares and mass injections)

NUCLEAR LEVEL DENSITIES CORRECTED FOR FINITE SIZE EFFECTS

1992 ◽  
Vol 07 (17) ◽  
pp. 1503-1507 ◽  
Author(s):  
G.D. YEN ◽  
H.G. MILLER
Keyword(s):  
Density Of States ◽  
Size Effects ◽  
Particle Density ◽  
Level Density ◽  
Finite Size ◽  
Nuclear Level Density ◽  
Nuclear Level ◽  
Finite Size Effects ◽  
Level Densities ◽  
Single Particle Density

Finite size corrections in the calculation of nuclear level densities are considered within the framework of a Fermi gas model. A simple geometrical correction to the single particle density of states leads to an increase in the Fermi energy which drastically reduces the many body density of states. For light nuclei such as 24Mg, the nuclear level density at T≡3 MeVis reduced by roughly an order of magnitude when finite size effects are taken into account and the reduction is more pronounced in heavier systems such as 208Pb.

Perfect Gas

2017 ◽  
Author(s):  
Jochen Rau
Keyword(s):  
Low Temperature ◽  
Black Body ◽  
Black Body Radiation ◽  
Einstein Condensation ◽  
Quantum Gas ◽  
Perfect Gas ◽  
Special Cases ◽  
Planck Distribution ◽  
Bose Einstein ◽  
Boltzmann Law

The perfect gas is perhaps the most prominent application of statistical mechanics and for this reason merits a chapter of its own. This chapter briefly reviews the quantum theory of many identical particles, in particular the distinction between bosons and fermions, and then develops the general theory of the perfect quantum gas. It considers a number of limits and special cases: the classical limit; the Fermi gas at low temperature; the Bose gas at low temperature which undergoes Bose–Einstein condensation; as well as black-body radiation. For the latter we derive the Stefan–Boltzmann law, the Planck distribution, and Wien’s displacement law. This chapter also discusses the effects of a possible internal dynamics of the constituent molecules on the thermodynamic properties of a gas. Finally, it extends the theory of the perfect gas to dilute solutions.

scholarly journals Detailed structure of the X-ray jet in 4C 19.44 (PKS1354+195)

2006 ◽  
Vol 2 (S238) ◽  
pp. 443-444
Author(s):  
D. A. Schwartz ◽  
D. E. Harris ◽  
H. Landt ◽  
A. Siemiginowska ◽  
E. S. Perlman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Density ◽  
Relativistic Particle ◽  
Particle Energy ◽  
Microwave Background ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Doppler Factor ◽  
The Magnetic Field

AbstractWe investigate the variations of the magnetic field, Doppler factor, and relativistic particle density along the jet of a quasar at z=0.72. We chose 4C 19.44 for this study because of its length and straight morphology. The 18 arcsec length of the jet provides many independent resolution elements in the Chandra X-ray image. The straightness suggests that geometry factors, although uncertain, are almost constant along the jet. We assume the X-ray emission is from inverse Compton scattering of the cosmic microwave background. With the aid of assumptions about jet alignment, equipartition between magnetic-field and relativistic-particle energy, and filling factors, we find that the jet is in bulk relativistic motion with a Doppler factor ≈ 6 at an angle no more than 10∘ to the line of sight over de-projected distances ≈ 150–600 kpc from the quasar, and with a magnetic field ≈10 μGauss.

scholarly journals Implementation of higher-order velocity mapping between marker particles and grid in the particle-in-cell code XGC

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Albert Mollén ◽  
M. F. Adams ◽  
M. G. Knepley ◽  
R. Hager ◽  
C. S. Chang
Keyword(s):  
Distribution Function ◽  
Particle Density ◽  
Particle Energy ◽  
Mapping Technique ◽  
Fusion Plasmas ◽  
Velocity Mapping ◽  
Bilinear Mapping ◽  
Particle In Cell ◽  
Function Information ◽  
Pseudo Inverse

The global total- $f$ gyrokinetic particle-in-cell code XGC, used to study transport in magnetic fusion plasmas or to couple with a core gyrokinetic code while functioning as an edge gyrokinetic code, implements a five-dimensional continuum grid to perform the dissipative operations, such as plasma collisions, or to exchange the particle distribution function information with a core code. To transfer the distribution function between marker particles and a rectangular two-dimensional velocity-space grid, XGC employs a bilinear mapping. The conservation of particle density and momentum is accurate enough in this bilinear operation, but the error in the particle energy conservation can become undesirably large and cause non-negligible numerical heating in a steep edge pedestal. In the present work we update XGC to use a novel mapping technique, based on the calculation of a pseudo-inverse, to exactly preserve moments up to the order of the discretization space. We describe the details of the implementation and we demonstrate the reduced interpolation error for a tokamak test plasma using first- and second-order elements with the pseudo-inverse method and comparing with the bilinear mapping.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

Sem/X-Ray Applications to the Forensic Science Field

1976 ◽  
Vol 34 ◽  
pp. 390-391
Author(s):  
K. Culbreth
Keyword(s):  
Forensic Science ◽  
Depth Of Field ◽  
Surface Phenomena ◽  
Criminal Cases ◽  
Forensic Evidence ◽  
Science Field ◽  
X Ray ◽  
Hit And Run ◽  
Evaluation Of Evidence ◽  
Scanning Electron

The introduction of scanning electron microscopy and energy dispersive x-ray analysis to forensic science has provided additional methods by which investigative evidence can be analyzed. The importance of evidence from the scene of a crime or from the personal belongings of a victim and suspect has resulted in the development and evaluation of SEM/x-ray analysis applications to various types of forensic evidence. The intent of this paper is to describe some of these applications and to relate their importance to the investigation of criminal cases.The depth of field and high resolution of the SEM are an asset to the evaluation of evidence with respect to surface phenomena and physical matches (1). Fig. 1 shows a Phillips screw which has been reconstructed after the head and shank were separated during a hit-and-run accident.

Depletion of coating color components in the blade coating process circulation

TAPPI Journal ◽  
2011 ◽  
Vol 10 (9) ◽  
pp. 17-23 ◽  
Author(s):  
ANNE RUTANEN ◽  
MARTTI TOIVAKKA
Keyword(s):  
Fine Particles ◽  
Particle Density ◽  
Stable Process ◽  
Size Fraction ◽  
Color Stability ◽  
Strong Interactions ◽  
Coating Process ◽  
Size Segregation ◽  
Coating Color ◽  
Average Size

Coating color stability, as defined by changes in its solid particle fraction, is important for runnability, quality, and costs of a paper coating operation. This study sought to determine whether the size or density of particles is important in size segregation in a pigment coating process. We used a laboratory coater to study changes in coating color composition during coating operations. The results suggest that size segregation occurs for high and low density particles. Regardless of the particle density, the fine particle size fraction (<0.2 μm) was the most prone for depletion, causing an increase in the average size of the particles. Strong interactions between the fine particles and other components also were associated with a low depletion tendency of fine particles. A stable process and improved efficiency of fine particles and binders can be achieved by controlling the depletion of fine particles.

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