In DFT or HF, is it more expensive to calculate the H matrix or to diagonalize it?

I was wondering: in common DFT (or Hartree-Fock) algorithms/codes, and in particular in solving the Roothan equation, what is the most computationally expensive part: 1- evaluate all the terms of...

01 February 2021 396 2 View

Warning in Lavaan, variance-covariance not positive definite!, model is not identified?

Dear colleagues, I am new to R, I have been using Amos for conducting CFA but came to learn that when dealing with Likert scale, Lavaan in R is a better tool to do such analysis. I started using...

30 December 2020 5,608 3 View

How can i figure out whether nanoparticles in my synthesis crosslinked or not?

i prepare protein nanoparticles. in one of my synthesis i use trifle amount of crosslinker and the nanoparticles stick in the bottom of plate. how can i understand that nanoparticles become...

03 December 2020 559 8 View

What is the best solver in OpenFOAM to study melt-water interaction?

During a severe accident in a nuclear reactor an energetic molten fuel/coolant interaction could happen, where a multiphase flow of a steam-water mixture in a region which contain drops of a...

29 November 2020 8,376 2 View

How can we define columns in 3D PLAXIS model for buildings existing near the excavation?

I started by a model using 3D PLAXIS to study the effect of deep excavations on existing buildings. The building was simulated as a surface plate with a surface load. Now I'm trying to do it as a...

29 November 2020 3,198 4 View

How to read forces from a file and apply them to a specified nodes in ANSYS APDL?

I want to apply different forces for every node. These force values are saved in .txt or .csv file. Can anybody help me to do that using APDL command. I attached Ansys input file for my model and...

15 November 2020 2,883 1 View

Where can I find off targets for Apis mellifera?

I would like to find off target sites for my sgRNA, however the more commonly used off target finders do not include apis meliifera, is there an application or website that would allow me to do...

09 November 2020 3,463 1 View

What is the best method to sterilize hydroxyapatite nanoparticles?

Powder insoluble

08 November 2020 509 3 View

Wrong cell dimension (cosAB)?

All input files with bravais lattice that contains an angle doesnt run in my Quantum espresso. i even tried running them in my friends laptop but the crash file displays the same problem. i hope...

03 November 2020 2,722 1 View

How Abaqus can generate lumped mass matrix with non zero values only at the diagonal ?

Hi everybody I generated mass matrix by Abaqus, but it has nonzero off diagonal values. I need to get lumped mass matrix with nonzero values only at the diagonal. In Ansys I can turn Lump on...

28 October 2020 5,960 4 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

flexibility of polymers chain

effect of double bond on the flexibility of polymers

07 April 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

Formulation of polymer color flakes

I am writing to request some information for making polymer color flakes. I would appreciate the help.

17 March 2021 0 0 View

How to compare two groups with only two measurements?

Hiiiii everyone! I have an enquiry on statistical analysis. I was looking for many forum and it's still cannot solve my problem. I want to compare means of two groups of data but only with two...

03 March 2021 8,796 3 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