scholarly journals ELECTRIC FORCE LINES OF THE DOUBLE REISSNER–NORDSTROM EXACT SOLUTION

2008 ◽  
Vol 17 (08) ◽  
pp. 1159-1177 ◽  
Author(s):  
ARMANDO PAOLINO ◽  
MARCO PIZZI
Keyword(s):  
Exact Solution ◽  
Black Hole ◽  
Electric Fields ◽  
Maxwell Equation ◽  
Naked Singularity ◽  
Extreme Case ◽  
The Other ◽  
Electric Force ◽  
Coordinate Systems ◽  
Equal Sign

Recently Alekseev and Belinski have presented a new exact solution to the Einstein–Maxwell equation which describes two Reissner–Nordstrom (RN) sources in reciprocal equilibrium (no struts or strings); one source is a naked singularity, the other is a black hole: this is the only possible configuration for two separable objects, apart from the well-known extreme case (mi = ei). In the present paper, after a brief summary of this solution, we study in some detail the coordinate systems used and the main features of the gravitational and electric fields. In particular, we graph the plots of the electric force lines in three qualitatively different situations: equal-sign charges, opposite charges and the case of a naked singularity near a neutral black hole.

EQUILIBRIUM CONFIGURATIONS IN THE DOUBLE REISSNER-NORDSTROM EXACT SOLUTION

2008 ◽  
Vol 23 (08) ◽  
pp. 1222-1225 ◽  
Author(s):  
MARCO PIZZI ◽  
ARMANDO PAOLINO
Keyword(s):  
Exact Solution ◽  
Black Hole ◽  
Naked Singularity ◽  
Electric Force ◽  
Equilibrium Configurations

The double Reissner-Nordstrom (RN) solution without strings nor struts, recently found by Alekseev and Belinski, shows that classically-forbidden equilibria are allowed for a naked singularity near a black hole. In the following we shows the plots of the electric force lines in three qualitatively different situations: equal-signed charges, opposite charges and the case of a naked singularity near a neutral black hole.

scholarly journals Solutions of Kerr Black Holes subject to Naked Singularity and Wormholes

2020 ◽  
Author(s):  
Deep Bhattacharjee
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Kerr Black Hole ◽  
Naked Singularity ◽  
The Other ◽  
Cauchy Horizon ◽  
White Hole ◽  
Kerr Black Holes ◽  
The Way

The existence of the “Naked Singularity" has been shown taking the advantage of the Ring Singularity of the Kerr Black Hole and thereby making the way to manipulate the mathematics by taking the larger root of Δ as zero and thereby vanishing the ergosphere and event horizon making the way for the naked ring singularity which can be easily connected via a cylindrical wormhole and as ‘a wormhole is a black hole without an event horizon’ therefore, this cylindrical connection paved the way for the Einstein-Rosen Bridge allowing particles or null rays to travel from one universe to another ending up in a future directed Cauchy horizon while changing constantly from spatial to temporal and again spatial paving the entrance to another Kerr Black hole (which would act as a white hole) in the other universes.

scholarly journals On small black holes, KK monopoles and solitonic 5-branes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Pablo A. Cano ◽  
Ángel Murcia ◽  
Pedro F. Ramírez ◽  
Alejandro Ruipérez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Compact Space ◽  
Naked Singularity ◽  
General System ◽  
Low Energy ◽  
The Other ◽  
Heterotic Strings ◽  
Similar Construction ◽  
Other Hand

Abstract We review and extend results on higher-curvature corrections to different configurations describing a superposition of heterotic strings, KK monopoles, solitonic 5-branes and momentum waves. Depending on which sources are present, the low-energy fields describe a black hole, a soliton or a naked singularity. We show that this property is unaltered when perturbative higher-curvature corrections are included, provided the sources are fixed. On the other hand, this character may be changed by appropriate introduction (or removal) of sources regardless of the presence of curvature corrections, which constitutes a non-perturbative modification of the departing system. The general system of multicenter KK monopoles and their 5-brane charge induced by higher-curvature corrections is discussed in some detail, with special attention paid to the possibility of merging monopoles. Our results are particularly relevant for small black holes (Dabholkar-Harvey states, DH), which remain singular after quadratic curvature corrections are taken into account. When there are four non-compact dimensions, we notice the existence of a black hole with regular horizon whose entropy coincides with that of the DH states, but the charges and supersymmetry preserved by both configurations are different. A similar construction with five non-compact dimensions is possible, in this case with the same charges as DH, although it fails to reproduce the DH entropy and supersymmetry. No such configuration exists if d > 5, which we interpret as reflecting the necessity of having a 5-brane wrapping the compact space.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

scholarly journals Black Hole Algorithm for Sustainable Design of Counterfort Retaining Walls

2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García
Keyword(s):  
Black Hole ◽  
Sustainable Design ◽  
Retaining Walls ◽  
The Other ◽  
Trade Off ◽  
Construction Company ◽  
Geometric Variables ◽  
The Stability ◽  
The Cost ◽  
Black Hole Algorithm

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.

scholarly journals Pulsed Electric Fields to Improve the Use of Non-Saccharomyces Starters in Red Wines

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1472
Author(s):  
Cristian Vaquero ◽  
Iris Loira ◽  
Javier Raso ◽  
Ignacio Álvarez ◽  
Carlota Delso ◽  
...  
Keyword(s):  
Electric Fields ◽  
Pulsed Electric Fields ◽  
The Other ◽  
Red Wines ◽  
Torulaspora Delbrueckii ◽  
Wild Yeast ◽  
Wild Yeasts ◽  
Natural Foods ◽  
Saccharomyces Yeasts ◽  
Lachancea Thermotolerans

New nonthermal technologies, including pulsed electric fields (PEF), open a new way to generate more natural foods while respecting their organoleptic qualities. PEF can reduce wild yeasts to improve the implantation of other yeasts and generate more desired metabolites. Two PEF treatments were applied; one with an intensity of 5 kV/cm was applied continuously to the must for further colour extraction, and a second treatment only to the must (without skins) after a 24-hour maceration of 17.5 kV/cm intensity, reducing its wild yeast load by up to 2 log CFU/mL, thus comparing the implantation and fermentation of inoculated non-Saccharomyces yeasts. In general, those treated with PEF preserved more total esters and formed more anthocyanins, including vitisin A, due to better implantation of the inoculated yeasts. It should be noted that the yeast Lachancea thermotolerans that had received PEF treatment produced four-fold more lactic acid (3.62 ± 0.84 g/L) than the control of the same yeast, and Hanseniaspora vineae with PEF produced almost three-fold more 2-phenylethyl acetate than the rest. On the other hand, 3-ethoxy-1-propanol was not observed at the end of the fermentation with a Torulaspora delbrueckii (Td) control but in the Td PEF, it was observed (3.17 ± 0.58 mg/L).

Study of Oscillating Flow of Viscoelastic Fluid With the Fractional Maxwell Model

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Jiu-hong Jia ◽  
Hong-xing Hua
Keyword(s):  
Exact Solution ◽  
Petroleum Chemistry ◽  
Viscoelastic Fluid ◽  
Maxwell Model ◽  
The Other ◽  
Oscillating Flow ◽  
Model Parameters ◽  
Series Approximation ◽  
Phase Lags ◽  
Annular Effect

The oscillating flow of the viscoelastic fluid in cylindrical pipes has been applied in many fields, such as industries of petroleum, chemistry, and bioengineering. It is studied using the fractional derivative Maxwell model in this paper. The exact solution is obtained utilizing a simpler and more reasonable technique. According to this velocity solution, the time-velocity profile of one kind of viscoelastic fluid is analyzed. From analysis, it is found that the flow behaves like the Newton fluid when the oscillating frequency is low, and the flow reversal occurs when the oscillating frequency is high. Moreover, two series approximations for the velocity are obtained and analyzed for different model parameters. In one series approximation, the velocity is parabolic in profile, while in the other series approximation, the velocity presents three characteristics: (1) it is independent of radius and at the centerline is smaller than that of steady Poiseuille flow, (2) the phase lags about 90deg with respect to the imposed pressure gradient, and (3) the Richardson annular effect is found near the wall.

Correlations of substituent effects on proton and fluorine chemical shifts with inverse ionization potentials

1967 ◽  
Vol 45 (24) ◽  
pp. 3143-3151 ◽  
Author(s):  
T. Schaefer ◽  
F. Hruska ◽  
H. M. Hutton
Keyword(s):  
Electric Fields ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Group Iv ◽  
The Other ◽  
Ionization Potentials ◽  
Time Dependent ◽  
Practical Application ◽  
Methyl Proton ◽  
Proton Chemical Shifts

The fluorine and proton chemical shifts in some geminally disubstituted vinylidene fluorides and ethylenes are discussed. For these compounds, at least, there are difficulties with an interpretation based on intramolecular time-dependent electric fields. On the other hand, the shifts correlate with the inverse ionization potentials of the substituents, indicating a paramagnetic effect arising from the second term in Ramsey's expression. It is suggested that the effect operates via the bonds and not across space. Methyl proton shifts in a series of substituted methyl compounds of group IV, V, and VI elements show similar correlations. A practical application of the correlation to spectral analysis problems is given.

TWO FAMILIES OF EXACT DISKS WITH A CENTRAL BLACK HOLE

1996 ◽  
Vol 05 (01) ◽  
pp. 53-63 ◽  
Author(s):  
JOSÉ P.S. LEMOS ◽  
PATRICIO S. LETELIER
Keyword(s):  
Black Hole ◽  
Topological Defect ◽  
Rotational Velocity ◽  
The Other ◽  
Central Black Hole ◽  
Counter Rotation ◽  
Infinite Extent ◽  
Self Similar ◽  
Physical Effects ◽  
Many Particles

The gravitational field of a configuration formed by a static disk and a Schwarzschild black hole is analysed for two families of disks. The matter of the disks is made of counter-rotating particles with as many particles rotating to one side as to the other, in such a way that the net angular momentum is zero and the disk is static. The first family consists of peculiar disks, in the sense that they are generated by two opposite dipoles. The particles of the disk have no pressure or centrifugal support. However, when there is a central black hole, centrifugal balance in the form of counter-rotation appears. The second family is a one parameter family of self-similar disks which includes at one end a Newtonian disk, and at the other a topological defect of spacetime. The presence of the black hole impresses more rotational velocity to the particles. These two families are of infinite extent. Some interesting physical effects are studied.

scholarly journals The thermodynamic theory of black holes

1977 ◽  
Vol 353 (1675) ◽  
pp. 499-521 ◽  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Energy Momentum Tensor ◽  
Heat Bath ◽  
Naked Singularity ◽  
Momentum Tensor ◽  
Thermodynamic Theory ◽  
Model Systems ◽  
Quantum Energy ◽  
Third Law Of Thermodynamics

The thermodynamic theory underlying black hole processes is developed in detail and applied to model systems. I t is found that Kerr-Newman black holes undergo a phase transition at a = 0.68 M or Q = 0.86 M , where the heat capacity has an infinite discontinuity. Above the transition values the specific heat is positive, permitting isothermal equilibrium with a surrounding heat bath. Simple processes and stability criteria for various black hole situations are investigated. The limits for entropieally favoured black hole formation are found. The Nernst conditions for the third law of thermodynamics are not satisfied fully for black holes. There is no obvious thermodynamic reason why a black hole may not be cooled down below absolute zero and converted into a naked singularity. Quantum energy-momentum tensor calculations for uncharged black holes are extended to the Reissner-Nordstrom case, and found to be fully consistent with the thermodynamic picture for Q < M . For Q > M the model predicts that ‘naked’ collapse also produces radiation, with such intensity that the collapsing matter is entirely evaporated away before a naked singularity can form.

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