What is the best method for tracking the sun position, is-it by solar position calculation along the day of the year or by other method?

In solar energy application, often we should know the sun position at each instant. With the sun position calculation, I think we can establish a database for this purpose. Then we can use-it for...

31 December 2014 7,264 12 View

In multilayer PV solar cells, how can I choose the materials (gap and contact type) in order to increase efficiency ?

When the PV solar cell is used in a multi layer form, the goal is to benefit of a large interval of solar radiations. I think that the gap and the contact of different layers must have certain...

31 December 2014 3,584 4 View

Why we use the term of "optical constants" of a material in spite of their variations ? is-it by misnomer ?

Optical constants as well as the gap, represent the signing of a material. They must be specific for this material. However, optical constants depend of the size of the crystallites which form the...

11 December 2014 5,742 3 View

Can we predict barrier potential in a contact metal-semiconductor or semiconductor-semiconductor using a theoretical approach ?

From band structure obtained with an existing calculation method , can we reach the result relating to the contact barrier between two materials ?

11 December 2014 5,487 13 View

There are much old films which are colored later. How we proceed to retrieve the suitable color for original picture ?

There are much old films which are colored later. The obtained result seems to be satisfactory. The colors can be different from the originals but it is sufficient for mistaking the human eyes....

11 December 2014 8,546 1 View

The IR radiations are harmful for the performances of photovoltaic solar cells; how is-it possible to eliminate these kind of radiations ?

Among the parameters which decrease the efficiency of the photovoltaic solar cells, we can note the solar IR radiations. This kind of radiation increases the temperature and then disturbs often...

11 December 2014 447 17 View

Is it possible to obtain a natural colored image using electron microscopy or ecography ?

Until today, a good colored image is obtained using exclusively light. Electron microscope uses electrons and echograph uses ultrason. That gives only gray images.

10 November 2014 7,733 11 View

What kind of chemical products are generally used in order to target a given thin film by the CBD technique?

08 September 2014 9,211 2 View

What is the best chemical solution which can be used to obtain tungsten oxide in the framework of chemical bath deposition (CBD)?

Especially to target the WO3 oxide.

02 March 2014 2,843 2 View

Why does the energy gap of a quantum dot vary with its dimension?

Because of the gap of each material represents a signature of this material, why is it not the case for a quantum dot made with the given material.

01 February 2014 8,339 3 View

Physics: Why do we describe light by referring to its wavelength, but microwaves and radar pulses by referring to their frequency?

In physics, the description of the properties of light generally refers to its wavelength (nm), while in the range of microwaves and radio waves we refer to the frequency of a signal (e.g. kHz or...

03 March 2021 1,682 3 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

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

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View

What is the density for pva electrospining?

I'm Juan Carlos, a high school student who is working with electropinning, I made an electropinning machine with a 21g needle and a 30kv high voltage source and the distance between my needle is...

28 February 2021 298 3 View

What is Flat Lens Antenna?

28 February 2021 5,433 3 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

Should we reduce the standard unit of length to 0.31951540592 meter ?

The reasoning behind this question is to align the ratios of the proton potential in energy per charge to the speed of light in distance per time. As these two dimensions appear to be related,...

27 February 2021 947 7 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