Does gravitational repulsion exist according to the Schwarzschild field?

There has been much speculation that the Schwarzschild field harbors regions of gravitational repulsion, witnessed by a positive acceleration. The criterion is that the radial velocity should be...

05 June 2018 7,728 19 View

Are the Renyi and Havdra-Charvat (aka Tsallis) entropies real entropies?

These 'entropies' depend upon a parameter, which can be varied between two limits. In those limits they reduce to the Shannon-Gibbs and Hartley-Boltzmann entropies. If such entropies did exist...

04 May 2013 9,739 9 View

How can the Schwarzschild metric predict that the circumference of a circle is 2pi r and yet the distance along the radius is greater than the difference?

It is impossible that the radial distance between any two points be greater than their difference. Also the appeal to Newton's law at large distances and a weak field forms part of the concept of...

04 May 2013 2,321 13 View

Does inflationary cosmology violate Einstein's equation?

The zero-divergence property of the Einstein field equation gives the condition for an adiabatic expansion. Hence there can be no entropy increase due to reheating at the end of the inflationary...

03 April 2013 8,679 94 View

Does the Robertson-Walker metric coincide with any of the known metrics of constant curvature of non-Euclidean geometry?

In every textbook on cosmology, with the exception of Robertson and Noonan, "Relativity and Cosmology" and "A New Perspective in Relativity", the square of the radial coordinate is taken to be...

03 April 2013 8,420 23 View

How can black holes emit black body radiation when the only things that emits black body radiation are black bodies?

The conclusion is based upon a look-a-like appearance between the frequency spectrum of an exponential frequency shift due to acceleration. Although the frequency shift should be due to a uniform...

03 April 2013 5,723 28 View

What is the energy density that appears in the energy-momentum tensor in Einstein's equations?

The thermal equation of state p=w e, where w is the ratio of the pressure, p, to the internal energy density, e, would identify it as the latter. If that were the case w would vary between 1/3 for...

03 April 2013 8,285 1 View

How can a negative pressure drive inflation, and where did all the entropy come from during inflation?

From its thermodynamic definition, a negative pressure would cause the volume to contract in order for the entropy to increase.

02 March 2013 9,398 15 View

How can absolute temperature ever be proportional to acceleration?

The so-called Unruh temperature follows from an incorrect equivalence between the phase of the wave function as being given by the ratio of the classical action to Planck's constant and the...

02 March 2013 5,840 11 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

i have some problem with chtMultiRegionSimpleFoam

--> FOAM FATAL ERROR: Maximum number of iterations exceeded From function Foam::scalar Foam::species::thermo::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar) const) const [with Thermo = Foam::hConstThermo >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo = Foam::species::thermo >, Foam::sensibleEnthalpy>] in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66. FOAM aborting #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::error::abort() at ??:? #2 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::calculate() at ??:? #3 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::correct() at ??:? #4 ? at ??:? #5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #6 ? at ??:?

24 March 2021 0 0 View

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10? Since, the growth curve from day 2 to 10 won't be like the "Logistic curve" it might not follow logistic...

03 March 2021 1,401 3 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View

What techniques can I use to determine the miscibility of polymer blends?

The term miscibility refers to the single-phase state in thermodynamics. I do not mean the compatibility of different components. To determine the miscibility I know several techniques such as...

03 March 2021 4,107 4 View

Resistor definition in Piezoelectric bimorph with ANSYS workbench

Hello, good day! I am trying to simulate similar bimorph piezoelectric harvester with below commands. However, the output power doesn't change with resistor value. Please help to find the reason. ET,10,CIRCU94,0 !SET UP RESISTOR R,1,100000 !RESISTANCE VALUE TYPE,10 !SET ELEMENT TYPE E,1,2 !CREATE RESISTOR BETWEEN NODES 1 AND 2 Thanks in advance Regards,

02 March 2021 0 0 View

Why are the velocities so high in my Boussinesq approximation Fluent simulation?

Hello, I have a mechanism where air rises due to convective flows. In this simulation, nothing is driving the air except this. I understand that the Boussinesq approximation only works for small...

02 March 2021 4,910 3 View

What is the characteristic length to determine the Reynolds number for the scattered turbulent fluid flow?

Dear all, I just saw this example in FB on the difference between laminar flow and turbulent flow. The flow from a pipe hits the sink and scattered. The flow from the pipe is characterized as...

02 March 2021 1,999 5 View