Questions tagged [radiation]

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1answer
15 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 ...
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0answers
45 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,...
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1answer
68 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 ...
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1answer
12 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) ...
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1answer
22 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 = ...
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1answer
38 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 ...
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1answer
26 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 ...
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0answers
16 views

Thermal radiation measurements: Looking for ~100 Hz BW, broadband (1-20 um) NIR/MIR detector

I am looking for a detector with about 100 Hz bandwidth, that has broad and ideally uniform absorbtance in the 1-20 um range. I need to be able to pickup signals in the 1 uW range with SNR >10, ...
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0answers
19 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 ...
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1answer
48 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 ...
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1answer
480 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 ...
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0answers
93 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 ...
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1answer
68 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 ...
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2answers
77 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?
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0answers
24 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 ...
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0answers
2k 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 ...
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1answer
162 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 ...
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3answers
84 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 ...
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1answer
128 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 (...
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2answers
526 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 ...
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1answer
273 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 ...
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1answer
939 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 ...