Recent content by damightytom

Hello. I was wondering if anyone could give me their perspective on my problem. I know it's a bit tabu doing the maths and calculations for other people but I am at a loss here. I lack the textbooks and therefore the basics i need to understand what you guys are trying to tell me.

Thanks a lot for that picture. Unfortunately your kind efforts have been in vain. I don't understand how that picture can help me.

Hi again, yes this really got me into the ballpark. I helped me a lot to understand my problem, at the time you answered i don't think i really understood what happened. since i have the U-values for both materials and their thickness, 3mm i can calculate R with the U= 1/R formula. U...

I have been ill for the last couple of days so haven't been at work, but I'm ready to tackle this problem again. I'll study your link and the ones above yours and I'll will probably come back with questions if I don't understand it. Thank you for the assistance.

Really could use some guidance on how I can calculate the Heat flow rate without knowing the temperature inside the enclosure.

I'm having trouble wrapping my head around the Heat flow rate. If the outside temperature is 20 °C the temperature inside the enclosure is very likely to be higher. Which results in a Delta Temperature of a positive inside the enclosure. The heat "wants" to go out to the coocler ambient...

Thank you! Alright I have the heat transfer coefficiants for Aluminium = 5,882 W/m^2 and Some plastic that's similar to the one I am planning to use = 3,448W/m^2 It does not have any fans it's a fully enclosed system. It's an IP-classified electronic box. The aluminium one is a cylinder shape...

Thank you. I see now that now. I use a nominal value of specific heat now on air witch is around 1.0 KJ/Kg.K With a volume of 0,0026m^3 and a weight of 0.00338kg of air in that volume I get a temperature rise of 1,5 Kelvin from applying 5W. Does that sound reasonable? And now when I want to...

This is a new field for me so its a struggle. Care to explain steady state and how I could use it? deltaT = Q/ (mass*CP) deltaT = (5w*t) / ((density*volume)*CP) Am I getting that right or am I still missunderstanding it?

Im trying to compare two enclosures, one is plastic and one is aluminium. So I figured I would calculate the air temperature inside the enclosure. For the plastic enclosure with an volume of 0,00097m3 (to simplify I make the assumption that the enclosure is empty and filled with air. That has a...

Hi I have an enclosure with an electrical heater that runs on 5W. Im trying to figuring out how warm the enclosure gets after a set amount of time. I need help with the strategy on how to tacle this problem. The heater warms up the air inside the enclosure (Specific heat) then the enclosure...

Homework Statement A fair coin is tossed 491 times. The total number of heads or tails is then even or uneven. Is the probability that the head will result in an even result equal to 1/2 Motivate your answer with a strict mathematical proof. Homework Equations I am having some trouble...

Homework Statement Hi I could use some help getting an explanation that kinda twists my head a bit. I want to know what I'm missunderstanding so I can get this right from the beginning. ^c = complement U = union I want to simplify this set A U (A U B^c)^c intersect (A U C ) to...

d2z/dx2 = -(z – y) z''=-(z-y) q=[y';y''] y(1)=z'' y(2)=z' Can I do something like that so I have ekv=y(2); -(z-y) for the second equation? I'm out in very deep water, I would kinda know what to do if I saw dy/dx in the equations, but now I don't so I'm pretty much guessing.

Do I have to find the antiderivitive for d2y/dx2 in order to get dy/dx and then solve it? Or is there some kind of trick into getting dy/dx in the equation?