What is a relation between relaxation time and mean free path for ideal gas?

These two values should be interconnected throufg integral of collisions. But I can not find a clear formula.

10 November 2018 233 1 View

What do You think about the articles which quotation index on RG is high and reading index is low?

Is h-index really important when compared with the number of downloads for the researcher? How to tell fair h-index from the artifical one made through personal contacts&links and social...

04 May 2018 3,179 1 View

Any example of a quantum particle in unstable state and driven by harmonic force?

May be anyone may bring an example of such kind particle taking place in nuclear physics or solid state or smth else. For example an electron in disordered semiconducter situated at maximum point...

04 May 2016 6,060 6 View

Klein- Gordon equation for the spinless particle in potential field, how does it look?

I didn't find in literature K-G eq. for non-free particle. Anybody who knows please write me down it. Thanks in advance Viktor

01 February 2016 1,935 5 View

May exist the force upon point mass directed along its velocity?

The opposite directed one is e.g. the drag force. T here should be a fundamental reason for this non-existing. What is?

04 May 2015 227 0 View

Mechanics

Has anybody got a Simple explaination of the Rattleback behaviour?

08 September 2014 4,894 1 View

Mechanical effort depending on acceleration - any thoughts?

In Newtons II law the force F acting on a body may depend on time, position and velocity but not acceleration. Otherwise the parallelogram principle doesn't operate for partial accelerations. And...

07 August 2014 9,527 9 View

Could you recommend any books about Number Theory?

Beginner level books. High level books. Analytical Number Theory. Algebraic Number Theory. Combinatorical Number Theory. Books about partitions. Books about primes.

03 March 2021 7,174 5 View

Arena simulation - how do i model the following model in ARENA (see description) (new to ARENA)?

Hello, I'm fairly new to ARENA and I have the following problem: I have two queues in which, in each queue, a different order type arrives (both having an arrival rate of exponential 10). Order...

02 March 2021 2,431 3 View

What is Flat Lens Antenna?

28 February 2021 5,433 3 View

Any specific pipeline or parameter to analyse total transcriptomics study of brain tissue samples?

I have two groups of brain samples, control and treated for example. It was total RNA nova seq sequencing. I tried all the available pipeline like: star+rsem+deseq2, Hista+stringtie+cuffdiff,...

27 February 2021 356 6 View

Can impedance of antenna be less than 50 ohms?

I am simulating helix antenna in hfss, right now, giving excitation with 50 ohms port. When I see the results of Z parameter (real). It shows lower than 50 ohms. Do not understand, if it can be...

27 February 2021 4,218 7 View

High aspect ratio hexahedral mesh optimization solver?

I am interested in evaluating mesh optimization solvers that converge to high aspect ratio unstructured hexahedral grids. In other words, I am interested in a solver that optimizes warpage,...

26 February 2021 7,279 2 View

What are the application of Fixed points thoery in Chemistry.?

It is said that fixed point theory has lot of applications not in the field of mathematics only but also in various areas. So I am looking for applications in Chemistry only..

26 February 2021 3,533 1 View

How to interpolate from a time-series database ?

Hi, I am having trouble with a problem, in the field of Optimal Control and the generation of optimal time-series. Let's consider a system, whose dynamics are represented by dx/dt =...

24 February 2021 9,105 2 View

How to constrain genetic algorithm input u?

My real system (buck converter) can only take an input of 0 to 1 (duty ratio) and I need to constrain the system so the controller action keeps within this bounds. How can I do this? The code for...

22 February 2021 2,125 3 View

Helix antenna coupling problem?

Dealing with a helix antenna, made with flexible material and not rigid like using a PCB board or wire. At the beginning of the helix is too close to the ground plane, causing coupling. How can I...

21 February 2021 4,453 3 View