Recent content by Imolopa

Thanks for the input! I editted the main question now to make it clearer. Yes I mean time over water.

When the total lifetime of an extratropical cyclone over the ocean in the Northern Atlantic-region gets longer (within the same season): - Do the total precipitation sums increase? - Does the precipitation intensities increase? - Does the intensity of the cyclone increase? For example what...

Yes I have had a subject in thermodynamics at university last year. However we havn't gone through combustion in that course, just barely. The equation from my thermodynamics book that we used in the course from a chapter that we did not go through is: W_cv - Q_cv = HV + delta H_r - delta H p +...

Homework Statement [/B] Im trying to find the efficiency of a gasoline engine regarded as a control volume. Am I right to use the HV as total energy input into the system? Assuming the enthalpy of formation of the fuel can't be found. I am really wondering if enthalpy of formation equals the...

Ok so as I can see you are adding and subtracting Zm twice, for simplicity we can say that it is the same as adding 1 and removing 1, and as a result not actually changing anything when it comes to the total sum/quantity as it remains the same. This leads me to guess that the method is used so...

Thanks for the explanation, I tried reading the linked document, but can't seem to find an explanation/understand the reasoning for the lowermost question in this post. However it's not intuitively clear to me yet. As I understand it so far: - During β- decay a neutron n from the nucleus is...

When dealing with a beta ^+ decay in the calculation of the disintegration energy Q, one includes the mass of 2 electrons. But the output result is 1 electron in the fundamental reaction: p => n + ( e^+ ) + v Where the neutron n has a neutral charge and the neutrino v has Z = 0. So why does...

I believe I found the answer: when the difference in volume and pressure is zero the difference in internal energy will equal the difference in enthalpies

Yes I am wondering why one equation uses enthalpy and the other internal energy. I'm not sure I'm answering some of your questions, but as I understand it: The first equation is the energy equation that refers to an instantaneous process, where the mass flow is steady state, the whole equation...

I believe my edit in orginal post describes the situation a bit better now. I can't edit the original post anymore, so adding here: subindex e denotes the exit point at the control volume CV (where the working fluid exits, or more precisely the exit state of the working fluid in terms of...

I've been given the following relations where as I understand it subindex 2 equals subindex e and subindex 1 equals subindex i: ***EDIT*** More accurately subindex 1; initial state of a control mass subindex 2: end state of a control mass (end state is simply state 2 in the problem at hand)...

Thanks corrected the units. Interesting, so the critical factor here is the roughness length z_0. As we can see the results are highly sensitive to its value: z0= 1 => z0e3 = 20 m z0= 2.5 => z0e3 = 50 m z0 = 5 => z0e3 = 100 m z0 = 10 => z0e3 = 200 m z0 = 20 => z0e3 = 402 m And it seems like...

To approximate windspeeds we normally use the natural logarithm relation: u_air = V ln [ (z-d) / z_0 ]Where: V - Characteristic speed, constant z - height from the ground z_0 - roughness length, constant d - zero plane displacement, constant The Betz limit tells us that in theory that the max...

Thank you! So to conclude we can say that it is more accurate to use enthalpies instead of constant specific heats, right?

Let's get back to my initial question, and now let's assume that we don't have the values for enthalpy h available. Given the following relation that is approximately true: h2 - h1 = Cp(T2-T1) Now given that Cp is a function of the temperature T by the formula: Cp0 = C0 + C1θ + C2θ2 + C3θ3...