Cycle Definition and 617 Threads

Homework Statement Hi all I'm a little confused about work in gases. I thought I knew it now I'm not so sure. Basically I'm answering a question about work done on the gas in a reversible cycle where a change in temperature (T1 -T2)at constant volume (V1) is followed by a change in volume at...

greetings, consider a wire which is subjected to AC supply.now consider a point X anywhere on wire. now what will be the potential of that point during the positive and negative halfcycle of sinusoidal AC?what will be the direction of current? thanks

Homework Statement Find (classify) all graphs with n vertices who's Euler's path is the same as their Hamiltonian cycle. The Attempt at a Solution I'd say that any regular graphs with a degree greater than n/2 (Dirac's Theorem) with and n divisible by 2 has both and Euler's path and a...

Hi all, long time reader first time poster! Just need a hand on this problem I've been stuck on for a few days Homework Statement Let r=(a_1,a_2...a_k) be in S_n. Suppose that ß is in S_n. Show that: ßrß^-1=(ß(a_1), ß(a_2)...ß(a_k)). Homework Equations The Attempt at a...

I am really struggling to get to grips with this question, ( struggling with material balance overall!) I can do dimple material balance however for things with a recycle stream or purge stream, really confuses me. I have the solution which I will post up, but I still don't get 'why' it...

I am wondering why water is used instead of air for the cold temperature source for a thermo cycle. My guess is the higher specific heat, which means the condenser unit can be smaller, and the mass flow rate less, which reduces the overall cost. Are there any other reasons to choose water...

so what book is the best when dealing with rankine cycle? i hope it has tons of problems with solution manual (for self-study purposes) pls. thanks

Just wondering if an idea I've had for a few years would actually work. If I had an engine where compression took place externally and the engine was only used for combustion for example. This engine would be direct injected. The fuel would be injected a very high pressures (common rail)...

Homework Statement How much heat is added over this cycle? During which processes? What is the heat expelled from d to a? Homework Equations http://img838.imageshack.us/img838/6270/29494670.png (Goes clockwise, abcda) The Attempt at a Solution I'm just generally confused...

Not sure if I've posted it on the correct thread but I don't think this classifies as advanced physics! I'm currently doing a physics assignment where we have to choose an energy source for a town in Australia (Broome). I am choosing to use a combined cycle gas turbine with natural gas as...

Hey all. I'm going through my textbook at the moment and struggling to figure out something. Here is the ideal Brayton cycle (same as in my text). Now I want to find q in, so: The first law of thermodynamics can be written as (neglecting changes in ke and pe): h_in - h_out + q_in - q_out +...

I am a 2nd year mech engg student. I have a basic doubt in condensers. The steam from turbine exhaust enters the condenser & gets condensed during which its specific volume decreases resulting in formation of partial vacuum. Now according to rankine cycle the process in a condenser is a isobaric...

Homework Statement A possible ideal-gas cycle operates as follows: (i) from an initial state (p1,V1) the gas is cooled at constant pressure to (p1,V2); (ii) the gas is heated at constant volume to (p2,V2); (iii) the gas expands adiabatically back to (p1,V1). Assuming constant heat...

Hello, I'm working on designing a rankine cycle steam power plant for a class and am trying to incorporate both reheat and a direct contact feedwater heater for regen. I've attempted to read up on this online but beyond some basic information it's hard to find anything. My question is should I...

This is a graph theory related question. Let G be a simple graph with min. degree k, where k>=2. Prove that G contains a cycle of length at least k+1. Am I suppose to use induction to prove G has a path length at least k first, then try to prove that G has a cycle of length at least k+1...

Homework Statement A reversible hear engine, operating in a cycle, withdraws heat from a high temperature reservoir (temperature consequently decreases). It performs work w, and rejects heat into a low-temperature reservoir(temperature consequently increases). The 2 reservoirs are...

Homework Statement An ideal Brayton cycle has a pressure ratio of 15 and can be analysed using air standard cycle assumptions. The gas temperature is 300K at the compressor inlet and 1500K at the turbine inlet. The compressor and turbine can be considered to be isentropic. For an...

Hey all! I'm trying to drive 5 speakers, each at a different preset frequency. I had been using the timer in my microcontroller to drive one, but it would get very messy to drive 5 simultaneously in software using just the 1 available timer. I've decided to drive each with a...

How to choose thermodynamic cycle for designing new jet engine? While designing new jet engine what parameters are important for choosing thermodynamic cycle? what other parameters are important for jet engine designing?

in a carnot cycle the gas expands adiabatically from 200 degrees to 500 degrees. what is the efficecy? and what is the entropy change of the gas during the expansion? sorry - i got the efficiency to be: 38.8% however I am unsure how to work out the entropy chance? any hints?

Is it possible (at least theoretically) to construct engine which uses Carnot cycle and two reservoirs with temperatures T_1<0<T_2 (one of them has negative temperature which is possible e.g. in case of two-state paramagnet). Such cycle would have efficiency greater then 1. (of course the...

Homework Statement Given the first cycle of a waveform: f(t)=2u(t)-2u(t-1)+u(t-2)-u(t-3) -- Plot the first cycle of the wave form -- Find the Fourier Coefficients Homework Equations Given above The Attempt at a Solution No idea yet. Will appreciate any help.

Homework Statement What is the total yield of ATP in the Krebs cycle for each glucose molecule that enters glycolysis? Homework Equations The Attempt at a Solution Not sure if the correct answer is 2 ATP or 24 ATP due to 6 NADH (= 18 ATP) oxidative phosphorylation 2 FADH2 (= 4...

Homework Statement A working substance goes through a cycle within which the absolute temperature varies n-fold, and the shape of the cycle is , where T is the absolute temperature, and S the entropy. Find the efficiency cycle. Homework Equations \frac{\delta Q_R}{T}=dS...

The Attempt at a Solution For a) I imagine it is easier to control the temperature of the hot reservoir because you could use a constant heat source e.g. bunsen burner. c) melting/freezing water. d) Entropy of the environment increases and the entropy of the universe always increases...

[SOLVED] Quick question about ''Cut-off ratio'' in the Diesel Cycle. So I've been studying the Diesel Cycle, and I've come up with something called the ''cut-off ratio'', which is simply a name for the ratio of expansion r_E. But I'm getting different definitions for this ratio. For example...

Homework Statement A monatomic gas has V1 P1 and T1 (volume pressure and temp) at state 1 The gas then goes through the following process adiabatic expansion to stage 2 (exapands to twice its volume) isovolumetric heating so it gets back to T1; stage 3 isothermal compression back to...

Homework Statement Why are the permutations (1 4 2 6)(2 3 4 5) and (1 4 5 6)(2 3) equal? It seems to me as if the first pair of 4-cycles want to permute 4->2 and 4->5, yielding a contradiction, but I suspect I've misunderstood something about composite cycles. I suspect it has something...

-------------------------------------------------------------------------------- The origin of life and humans is unknown.That is to say that humans do not know how they came into being and why humans come to this world. We only know that life and humanity is the product of natural...

Homework Statement i have an mechanical engineering problem. A gas taken thru a 4-process cycle has 1-2 isothermal volume ratio rv,2-3 isobaric constant pressure,3-4 isentropic reversable adiabatic and 4-1 isochocric constant volume. How do i formulate the thermal efficiency equation for it...

Would someone be kind enough to explain what happens to the operation of both transistors in both the positive cycle and the negative cycle of the input signal please? I'm having a hard time understanding how this works exactly. What I know is that with no input signal, both transistors have a...

Alright, I'm confused about why thermodynamic cycles can never have 100% efficiency. There reversible processes right? And a reversible process has zero change in entropy, so then why can't they achieve 100% efficiency. I thought entropy was the measure of energy that cannot be used. How would...

Homework Statement A breeder reactor is designed to work on a thorium fuel cycle. If the reactor generates a constant thermal power of 2.5GW and a production rate of 233U is 52kg per year. Find the breeding Ratio [You may assume the capture to fission ratio of 233U is 0.09 and the energy...

Homework Statement Sorry about the basic question, I haven't takena course on graph theory yet but need this for a course in computer science. The problem: Write a program whose input is an adjecancy matrix and whose output is the number of cycles of length 3 and 4. The Attempt at a...

Hey guys, I need to get some feedbacks from all of you here. Do you guys think it is possible for an engine to have a very low exhaust gas temperature and does not need any coolant radiator? The aim is simple, with lesser heat rejected through exhaust gas and radiator, there will be more...

Homework Statement An illuminated suspension of chloroplasts is actively carrying out photosynthesis. What would happen to the levels of 3-phosphoglycerate and Ribulose 1,5-Bisphosphate if the light was suddenly switched off? Homework Equations The Attempt at a Solution I...

Homework Statement 5.4: If sigma in S_n has cycle type n_1,...,n_r, what is sgn(sig)? (sgn is the sign homomorphism)Homework Equations sgn(sigma) = 1 if sigma is even. sgn(sigma) = -1 is sigma is odd cycle type is the length of the cycle type. If n_2 = 2, sigma has two 2-cycles.The Attempt at a...

Alright. So I have an idea, and I'm not sure if it has been thought up yet. So, We all know what the Big Bang is. I'm going to assume that you've heard of the big "Crunch", I believe it was called. Well, What if when the Universe comes together, or "crunch's" a big bang happens. All of...

Homework Statement 21. A heat engine operates in a cycle between temperatures 700 K and 400 K. The heat input to the engine during each cycle is 2800 J. What is the maximum possible work done by the engine in each cycle? (A) 1200 J (B) 1600 J (C) 2100 J (D) 2800 J (E) 4400 J I...

Homework Statement A monatomic ideal gas has pressure p_1 and temperature T_1. It is contained in a cylinder of volume V_1 with a movable piston, so that it can do work on the outside world. Consider the following three-step transformation of the gas: 1. The gas is heated at constant volume...

Hi guys, I want to run a for cycle with ode45 inside. However, some parameters that I define in odefun (the differential equation in order to dy/dt, for instance) assume different values in each iteration of that cycle. I find help examples showing odefun only receiving t and y... Is...

My textbook says, I checked the whole citric acid cycle, and only the conversion of succinyl coA requires ADP or GDP. I don't understand how a lack of this would make NADH accumulate. Could anyone explain this. Thanks a lot :smile:

Hi all, I wish to build a triggerable circuit that gives out a single-cycle, such as the one given in the pic attached (the middle one, with magenta and blue colours). While square/trapeziod/ramp cycles are good, even an exponential fall in the beginning and rise in the end would be fine (the...

An infinite line charge l is located along the z axis. A mass m that carries a charge q whose sign is opposite to that of l is in a circular orbit in the xy plane about the line charge. If m = 0.28 kg, q = 1.1 mC, l = 3.3 nC/m, and R = 0.25 m (the radius of the orbit), find the period. Help...

Homework Statement Given: A reheat Rankine cycle - Steams enter the high-pressure turbine at 12.5 MPa and 550C - It leaves at 2 MPa - Steam is reheated at constant pressure to 450C before it expands in the low pressure turbine - Isentropic efficiency of turbine = 85% - Isentropic...

(maybe it fits better in this forum) Hello, I have been asked an advice about waste heat to power systems (say wh2p). The available waste heat to be considered is a (dirty) gas in a temperature range between 250°C and 450°C. The useful power that could be generated would range between...

The fingerprint of the new solar cycle http://sidc.oma.be/news/119/welcome.html A Long Filament Erupts (December 14, 2009) http://soho.nascom.nasa.gov/pickoftheweek/old/11dec2009/ Solar Cycle 24 is off to a slow start...

Let A be the adjacency matrix of some graph G. I am aware that A^n counts paths of length n between vertices of G, and that for graphs without cycles and non-singular A, (I-A)^-1 counts the total number of paths between vertices of G (correct me if any of this is wrong).This is a very...

Hello all, I have recently been wondering whether there is a way to determine a fraction for which the decimal expansion is a cycle of n numbers? I would like to be able to work this out myself, but I can't wait until I start my mathematics degree. So any help would be greatly appreciated...

I've been trying to wrap my head around this one for a while. What are the drawbacks to using a brayton cycle solar generation setup? Here's the setup. It seems a car turbo is the cheapest and best suited so that's what I'll prototype if the idea gets that far. Atmosphere => Compressor =>...