How are excitons real when 'hole' itself is an abstract, theoretical concept?

As the explanation goes, hole is a figment to the absence of electron as it moves to some different energy state as a result of absorption of energy of some kind. That is, I think of holes as...

10 November 2018 3,801 11 View

Can philosophy be called as a science in itself? If not, what is the difference between the two?

If philosophy provides logical and rational explanations, how is it different from the subject of science?

11 December 2013 1,693 61 View

Why do the sharp interior and exterior corners of a product act as stress raisers or stress concentration points?

A hole, sharp corner, crack etc. act as points of high stress concentration. Is it just because of the lower surface area they provide, or is there another explanation?

02 March 2013 6,665 11 View

In power cycles, what does back work exactly mean? What are the advantages?

In power cycles, some of the output work of the turbine is fed back to drive the compressor, which is often quoted as back work. If we simply provide work input to the compressor by a separate...

31 December 2012 1,403 3 View

Justify how can process of temperature rise of an ideal substance be isentropic.

By Third Law of thermodynamics; s = k ln(p) where; s = entropy k=Boltzmann constant p= Probability of finding a molecule at a particular point When temperature rises, anyhow, Internal energy and...

11 December 2012 5,901 6 View

Why does the specific heat ratio decrease with an increase in temperature?

Specific heat ratio = Specific heat at constant pressure / Specific heat at constant volume

10 November 2012 2,208 13 View

"Entropy of the universe is ever-increasing"....my question is upto what point will it continue to rise???

In nature, processes and changes occur till they attain equilibrium or some maximum value. However, this term, Entropy, seems to defy this well established fact. If every process causes entropy to...

08 September 2012 7,105 13 View

What is the difference between grains and crystals? They are interchangeably used in a few texts I came across.

A text I read had this line: "finer crystal structure for better performance". After a lot of thinking it seemed as if the author meant about the finer grain structure. How should this confusion...

07 August 2012 6,452 5 View

Do the brittle materials have lower tensile strength than the ductile ones?

It is well known that brittle materials absorb lesser energy to fracture than the ductile materials. Does this imply that the brittle materials have lower tensile strength than the ductile...

07 August 2012 2,903 16 View

What is the reason that we say that the "Quasi-static" or equilibrium processes are most work efficient?

I haven't found any reasonable explanation to why we say that most work is delivered in quasi-static operations. Is it just that because they are frictionless or are there any other plausible...

07 August 2012 4,557 7 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

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 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

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 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

How the parameters (such as Mw, Chemical bonds, polymer bland and so on) affect the mechanic property of polymer (such as storage, loss modulus) ?

Anyone can recommend any books on such topics? Thanks in advance.

02 March 2021 8,457 2 View