Questions tagged [radiation]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0 votes
2 answers
59 views

Why is infrared used in thermal imaging and not microwave or radio wave or ultraviolet?

In my company, we use IR Thermography. But I was thinking, why IR? Why not microwave or radio wave or ultraviolet even. Is it because of some unique property of infrared or the cost-effectiveness? Or ...
user avatar
1 vote
2 answers
37 views

Strange units with UV water disinfection systems

When retrieving information about UV systems for water disinfection I frequently encounter minimum intensity values. e.g. here: Basics of UV disinfection, page 23 All those I find are given in a unit ...
user avatar
  • 344
1 vote
0 answers
27 views

How much would Jupiter heat up if you accelerate Jupiter out of orbit around the sun using fusion candles? [closed]

So, I responded to a post of someone saying that you could turn Jupiter into a spaceship using fusion candles. I mentioned that doing so would dramatically heat up the planet, especially if you were ...
user avatar
0 votes
2 answers
44 views

Why do we consider a wavelength range when defining spectral emissive power of a blackbody?

The spectral hemispherical emissive power of a blackbody is the amount of thermal energy emitted in the form of EMW lying in the wavelength range of $\lambda$ to $\lambda + d\lambda$ via thermal ...
user avatar
1 vote
4 answers
792 views

Can cables and wires for home internet emit harmful radiation?

I am installing internet services in my home and need to run wires (Ethernet, modem, router related) along the lower part of the wall near some beds. Can people sleeping in the beds be exposed to ...
user avatar
1 vote
0 answers
36 views

Where do I start with learning how to transfer data via RF

So I literally have no idea where to start but I know what I want to make. The goal is to somehow transmit 25mb/s of data across 15km with high penetration. Acceptable for reaching through trees and ...
user avatar
3 votes
1 answer
134 views

Trapping sun heat the most - greenhouse

Greenhouse have recently caught my attention lately, which yesterday I posted in Why greenhouse's inside temperature never been infinitely hot? From what I understand recently, greenhouse gases traps ...
user avatar
  • 93
2 votes
1 answer
49 views

Can air be ionized using microwaves?

I have been doing a good bit of research lately into a new form of electric "jet engine" developed by researchers in Wuhan, China; in the article summarizing the technologies used to produce ...
user avatar
  • 21
1 vote
0 answers
111 views

UV radiation simulation in ANSYS

I am setting up a simulation in fluent to estimate the UV radiation dosage of an air stream passing through a cylindrical duct with the UV source in line with its main axis. It is a very simple system,...
user avatar
  • 160
-1 votes
1 answer
135 views

How are the electronics and chips inside the microwave protected from the microwave radiation/energy?

Let's say I put in an endoscope like camera with the lens at the inside edge of the box and the wire behind metal sheet. Here's a mockup: Could use microwave reflecting or absorbing wrap to wrap the ...
user avatar
1 vote
1 answer
23 views

Melt plastic powder bed with radiant heat?

I want to melt a bed of plastic powder so that the powder bed once melted and then cooled forms a solid sheet of plastic. In order to melt the powder I'm thinking of passing a nichrome (Ni80/Cr20) ...
user avatar
  • 169
1 vote
1 answer
25 views

How to consider the dimension of a cylinder when computing its radiative budget?

I am trying to derive a heat budget model to estimate the temprature of very small a stationary vertical cylinder (1mm) under environmental conditions. Imagine a wooden stick. Simply put, I have R = ...
user avatar
1 vote
1 answer
46 views

Protect equipment against electromagnetic radiation [closed]

They say that in the near future high cosmic radiation is possible. In addition, the Earth’s magnetic field is likely to weaken. I want to create something like a camera that would protect against ...
user avatar
  • 121
2 votes
1 answer
33 views

Calculate FTIR-system response functions from measurements of a calibrated black body

I need to find the response of my FTIR spectrometer. I do have a calibrated black-body source (area-emitter) which I measured at various temperatures. The system operates in inverse cm, cm-1. My ...
user avatar
0 votes
0 answers
29 views

How good are graphene layers at shielding against ionizing radiation?

I assume every materials laboratory has ways to test properties of new materials. Has anyone ever tested graphene's properties at shielding ionizing radiations? I guess It could be a good candidate ...
user avatar
-1 votes
1 answer
64 views

What emits more radiation, cell network or wifi?

I've researched in the Internet but can't find any conclusive answer. When will your phone emit more radiation, downloading 1 Mb of data from a cell network (3G, 4G) or downloading the same amount of ...
user avatar
0 votes
1 answer
1k views

calculating the efficiency of a microwave oven

If I want to calculate the efficiency of a microwave oven, I have the input Energy (= power (watts) x time (s)) and the output which I measured using temperature difference (q=mct). So do I divide ...
user avatar
  • 1
1 vote
0 answers
139 views

Method to simulate a dipole antenna in salt water?

I am looking to simulate the radiation pattern of a 2.7Ghz half-wavelength dipole antenna immersed in salt water. I've been using Altair FEKO software to try and accomplish this. I've tried two ...
user avatar
1 vote
2 answers
162 views

Epoxy that can withstand up to 800C and is optically transparent?

I'm looking to use an epoxy in a high-temp environment like 800C, and one that is optically transparent at 450nm (not below 90% transmission). But i'm having trouble finding one. It can be made of any ...
user avatar
  • 11
0 votes
2 answers
97 views

Blackbody radiation

If we are able to see an object in a certain color,that means it reflects the color.A blackbody is one which has zero reflectivity.Then how come it is not black always?
user avatar
  • 129
1 vote
0 answers
28 views

Dose rate through shielding from Co-60 to verify Monte Carlo result?

I need to calculate the dose rate leaking from sealed Co-60 sources. Let's say the activity of a source is 7 TBq. The source is tube shaped, 2 mm radius and 10 mm in height. There is 5 cm of tungsten ...
user avatar
1 vote
0 answers
4k views

What is the gray-body emissivity value of air

Wonder if anyone would know what is the average thermal emissivity value of air relative to blackbody at near room temperatures? I am looking for that magical number between 0 and 1. Looked everywhere ...
user avatar
1 vote
1 answer
189 views

What is the inuition behind the radiation view factor reciprocity?

I have known that the view factor reciprosity is that Ai x Fij = Aj x Fji But i can't intuitively explain the logic behind this, i do know that the view factor Fij is the portion of the radiation ...
user avatar
  • 11
1 vote
3 answers
91 views

Radioactive Materials to Energy AT HOME

Is there a way to use a radioactive elements (Americium in my case, but for demo, any radioactive material) to create a usable amount of energy (Power small LED?) AT HOME! Using materials that can be ...
user avatar
-2 votes
1 answer
132 views

What thing will make phone emit more radiation? [closed]

I am looking about things will make phone emit more radiation and I found some case Bad mobile network signal Turn on Bluetooth and Wifi Moving fast When start dial When start send message Battery (...
user avatar
  • 107
2 votes
2 answers
635 views

Do smoke alarms become more sensitive as they get older?

From what I understand a smoke alarm works by emitting some sort of radioactive particle and then counting how many of these particles hit a receiver. When there is smoke in between, it blocks some of ...
user avatar
  • 121
0 votes
1 answer
428 views

Surface in the sun vs. surface in the shade [closed]

What is the difference in temperature between a surface in the sun as supposed to one in the shade and how is it calculated? For instance: What will the temperature be if a metal sheet lies in the ...
user avatar
4 votes
1 answer
1k views

Heat Transfer coefficient calculation for hot air flow inside rectangular duct

I am working on modeling of air-heater component. A simplified representation of system is as follows: Cold air flow enters steel duct at one end. Inside duct is Calrod heating element shaped as ...
user avatar