Thermal Definition and 1000 Threads

I have a cylinder that is separated with an insulator. In the internal cylinder there is a thermal source, while outside the insulator we have a thermal sink. The power of the internal cylinder is positive, while of the external one in total is negative. How I should interpet the results. Like...

I often think thermal fluctuations as random changes in the temperature but when it is said in the context "thermally fluctuate over the energy barrier" does it mean to classically overcome the barrier?

So I read that lithium hydroxide made from Li-7 is used as an anti-corrosion additive in light water reactors purely for the "longevity" and "well being" of the vessel and structural auxiliary elements like steam pipes etc. Lithium separation is a rather chemically "nasty" task if using the...

At first, I tried to calculate the heat energy required by doing this: I realized I should calculate heat energy separately instead of grouping glass and water together so I did this: But the answer is supposed to be 6.29 x 10^4. I don't know how to solve this. Can anyone help please? Thank you

Hi, The solution for this question is thermal energy lost= thermal energy gained 0.200x450x(300-T)=1.0x4200x(T-20) T=26 degrees celcius. However, I am struggling to grasp why (300-T) is used. I have always known a change in something to be final - initial. Therefore change in T= Final-...

Hello, I am not sure if this is the right place but I would appreciate some help. Basically I have been trying to accelerate the fading of the ink on thermally printer paper. “Receipts are typically printed on thermal paper, a chemically coated paper that produces text and image when the...

What materials would be suitable for a cylinder and piston that is thermally insulating, reasonably durable for low speeds and very slow cycle rates, and not be a carbon or silicon based polymer? I've been looking at manual lever operated espresso machines lately. Particularly ones that are...

Suppose a square shaped object has an initial length of L1 and final length (after thermal expansion) of L2. Initial temperature is T1 and final temperature is T2. Suppose it has an area of A. So initial area is A1 and final area is A2 (after thermal expansion). Here A1 = (L1)^2 and A2 = (L2)^2...

Hello, I'm trying to build a custom made fridge made by a cube by 120cm on each side. The material used to isolate the cube will be some polystyrene panels, with thickness s=4cm. Let's imagine to cool the dry air inside in order to reach the internal temperature of 8 degree Celsius, while the...

I am looking to approximately calculate the temperature change of a sample that was exposed to a laser pulse. Experimentally, we know the optical absorption, reflection, and transmission, as well as the source parameters for our laser system. I realize that I will have to make approximations...

Hi Guys, I am doing a Maxwell 3D&Icepak thermal simulation for a air coil. I want to get its temperature when loading 1.6A current. So I use Eddy Current type in Maxwell 3D and Temperature and Flow type in Icepak. Then I load 1.6A solid current and adaptive frequency of 800 MHz for the coil...

I am simulating a hot forging process in LS-Dyna. A tool is contacting a hot workpiece for 2 sec every 10 sec (--0 sec--contact--2 sec--no contact---10 sec--) in a factory. Since this is a continuous process, the tool should, at some point, attain steady temperature. I have tried to recreate it...

I'm trying to use my rudimentary understanding of material physics to understand a simple problem, and am getting stuck - I hope you can help! My idealized case involves a sheet of infinite extent in length and width direction, to which a linear thermal gradient in the depth dimension is...

We have the area of incandescence. Using that we can find the radius and subsequently the diameter. A=π* r^2 -----> r= 0.0025m so d=0.005m Using the formula (given by Clausius as we are not specified in question whether it's a Maxwellian distribution or not) Mean Free Path λ=...

<Using the hint, I tried to find the van der Waal constants in molar form. Since STP is mentioned, I used the unitary method relationship- 22.4 L=22400cm^3=1 molar V <To find a possible conversion standard between cm^3 and mol; which turned out to be 1cm^3= 4.46*10^-5 mol. <Then I used the...

I would like to be able to determine the current through a device for a given junction temperature. I am looking at a datasheet and notice that it gives the device power dissipation with different case temperatures. Since the maximum junction temperature is 175 C, I believe that means that lower...

This is a fluid dynamic simulation. The top area has 100 degrees Celsius. The bottom area has 0 degrees Celsius. And both are filled with an ideal gas which is 1-atmosphere pressure. Two areas are connected through the left small line. Another part is blocked. So heat transfer can only happen...

It is claimed 2D Graphene sheets can be used to harvest thermal energy while being at the same temperature as the surroundings in seeming contradiction to Feynman's *argument (in the popular accounts). However, the academic papers referenced below make the claim everything is well within known...

I know k is thermal conductivity but my teacher never told me about effective coefficient of thermal conductivity. I tried googling and found: $$k_{effective}=\frac{\Sigma{k.A}}{\Sigma A}$$ But I don't know the area to used that information. Is there another approach to do this question? Thanks

Suppose each side has initial length ##l##. The solution taught to me is as follows. Considering the lengths of the rods after expansion, we write $$\dfrac{3l^2}{4}\left(1+\mu\theta\right)^2+\dfrac{l^2}{4}\left(1+\alpha\theta\right)^2=l^2\left(1+\lambda\theta\right)^2$$ according to the...

Hello folks, I have a bit of a time sensitive question, if anyone happens to read this soon. A computer box consumes 80W power constantly. Outside temperature T= 290 Kelvin. Ambient pressure 10^5. If all the heat generated is expelled at 5 litres per second, estimate the inside...

Hello friends! We are installing a future provision for a Rocket Mass-type woodstove in our home. This is a future project but realized that we could take advantage of the open area between the footing and finished floor by adding an insulated block of concrete with PEX pipes for Heating and...

I'm trying to figure out how to relate expected thermal expansion of a uv cured polymer within a rigid cylinder to a modulus specification. The issue is the expected change in refractive index due to thermal expansion. The expansion coefficients are not available. Anybody have an idea. Do...

So if I have a tubular reactor for nanoparticle synthesis (PTFE tubes ID:2mm). The tubes are heated in a furnace. liquid Reagents at room temperature are pumped by a syringe pump and directed toward the furnace. The reagents decompose to form nanoparticles once they reach the steady-state...

I've tried to explicitly solve the Fourier's equation in cylindrical coordinates but I'm getting some messy integrals which cannot be solved analytically. Additionally my instructor said that there's a neat trick for this problem and it's possible to obtain the answer in a rather elementary...

Hello! Below is a figure of the thermal noise spectrum of an RLC circuit from a certain experiment. I am not sure I understand the shape. The spectrum is peaked around the resonant frequency. However, in thermal equilibrium, I would expect that the electrons to have random motions, so for a...

The total noise from other sources and thermal is ##N = N_{other} + N_{thermal}## ##N_{175}/ N_{275} = (N_{other} + \sqrt{2k(175)R\Delta f})/( N_{other} + \sqrt{2k(275)R\Delta f})## I'm not sure how to simplify the expression as ##N_{other} ## is unknown. If I assume ##N_{total} =...

I know that the Sun is at a very far distance from the lens, so I assume the rays are parallel and the image is formed at the focus (500mm away from the centre of the lens). How do I calculate the diameter of the image? The hint to solving this problem says that "The angular diameters of...

Good afternoon everyone! I've learned that thermal conductivity has a form of second-rank tensor. As you know, diagonal components of stress tensor mean normal stress and other components mean shear stress and like that do off-diagonal components of thermal conductivity tensor have some special...

Hi all, I am having trouble getting repeatable results from a linear regression formula that simply uses temperature vs load cell output especially with rapidly increasing/decreasing temperatures. This appears to be a result of the thermal co-efficient of our temperature sensor being almost...

Ca(HCO3)2 -> CaCO3 + H2O + CO2 First I evaluate the moles of calcium carbonate (don't mind the units, just to save time) ##\frac {80.0}{40,00+12.01+3*16,00}= 0,799 mol## From the equation, correct me if I am wrong , one mole of CaCO3 is proportional to one mole of CO2, so from this I can...

Hello everyone, Once I got through the VDW state equation I came to the expression of the thermal expansion coefficient. When I place the values I get an illogical answer. Is there a problem with the units? (Please ignore the values) Thanks. This is the unit equation I get to and get stuck:

Could I put this on here for answers please ? If produced a solid glass beam with a spiral column thorough the middle of it would the core be hotter or cooler than the surrounding air? If colder could it be use in conjunction with ground source technology to produce hot water? I not sure how to...

Frankly, i don't even know how to start this. I deducted from the solution, that they must have used power/(specific heat capacity x temperautre), however i don't understand how that will give the rate of flow of air. Could anybody help, please?

I tried using U=3/2 NKbT, but i don't seem to get the correct answer..

1-->2 (adiabatic) $$P_1V_1^γ=P_2V_2^γ$$ $$P_2=18,4.10^5Pa$$ $$T_1V_1^{1-\gamma}=T_2V_2^{1-\gamma}$$ $$T_2=429,32K$$ 2-->3 (isochoric) $$\frac{P_2}{T_2}=\frac{P_3}{T_3}$$ $$\frac{18,4.10^5}{429,32}=\frac{P_3}{T_3}$$ 3--> 4 (adiabatic) $$P_3V_3^{\gamma}=P_4V_4^{\gamma}$$...

Hi, in the Timoshenko’s book "Theory of elastic stability" one can find a case of simply supported rectangular plate uniformly compressed in one direction (compressive load is applied to shorter edges). The formula for critical load is: $$N_{cr}=\frac{\pi^{2} D}{b^{2}} \left( \frac{b}{a} +...

My idea is this: tensor stress is directly related to the internal pressure of a solid. That is to the force that the neighboring atoms exert each other in relation to a unit of surface. When I heat a solid we can have the phenomenon of thermal expansion: this is connected to the fact that a...

Hey guys, I have Thermal as a course in this (undergrad) semester and the teacher is very bad. Any book recommendations for me to study entirely on my own? This is what we have to cover in the course:

In a parallel connection heat is produced. R1 = 5 Ohm R2 = 10 Ohm What is the relation of W1/W2? 1:4 1:2 2:1 1:8 3:1 I’d tend to say 1:2, but I am not really sure…

The two volume treatise Bryce DeWitt, The global approach to quantum field theory, Oxford Univ. Press 2003. which discusses the canonical approach to dynamical quantum gravity, is probably responsible for the fact that the many worlds interpretation (MWI) of quantum mechanics has a sizable...

This is probably a common questions, but I can't find it answered anywhere... It is of course well known that the average number of thermal photons in a mode can be calculate from from the B-E distribution: <n>=\frac{1}{e^{hf/k_BT}-1} The usual understanding of this is that what we are...

I doing an experiment that involves thermal penetration of copper. Please advise me where to post if I choose the wrong spot. This experiment is being done with what I have on hand and my ability to work the materials. Materials 2.75 gal pot of water 6qt pressure cooker 100+lb of stripped...

I can only find papers relating to how they've used the model but nothing about the model.

We know that, Conduction Heat Transfer Q = KA(t2-t1)/thickness K is the coefficient of thermal conductivity. If T2 = 1020°C and T1= 22°C also consider we know A and thickness value. K depends on temperature. K varies with temperature. For all the materials we have a tabular data of K for...

So guys I had physics lab where we used Steam Generator, Pasco interface and Capstone. In a nutshell there is graph attached below and formula, please write the solution with this formula.

I have two bodies, one at a higher temperature say 1000°C (Body A) and the other is at 22°C (Body B). Body A emits Radiation (Surface to Surface interaction). The temperature of Body A is maintained by a constant supply of Energy. The Body B will absorb the Radiation Energy from Body A, and its...

First, I calculated the heat required for the ice to melt: Q=mLf Q=0.150×330 Q=49.5 J Then, I calculated the final temperature of the water by forming the following equation: Q=mcΔT −49.5=(0.15+0.35)×4200×(Tf −80) Tf=80.0 degrees Celcius But the answer says 32 degrees Celsius.

Hello, I'm searching for how magnetic field affects the thermal conductivity of the metal (such as steel in solid form). If someone suggests any article about it will be very helpful.