Cycle Definition and 617 Threads

Homework Statement One mole of an ideal gas is used as the working substance of an engine that operates on the cycle shown in the figure. B-C and D-A are reversible adiabatic processes. 1) Is the gas monoatomic or polyatomic? 2)What is the efficiency of the engine? Homework Equations None...

I have a general question about otto cycle. If we heat a gas with constant volume its temperature rise according to PV=mRT. However during Isentropic compression(delta Q and delta S is zero), the volume is becoming less and pressure is increasing but i don't know why the temperature should...

Homework Statement Consider an ideal gas whose volume is initially V_0=1cm^3 that is initially at P_0=1 atmosphere. It goes through a cycle a-b-c-a where b-c is at constant temperature. 1)According to the sketch, does the system absorb or release heat? 2)Calculate the heat exchange in a...

hey guys, just wanted to know, in the graph of the OTTO cycle in the link http://www.qrg.northwestern.edu/ther...Pv-diagram.gif are stage (2-3) and (1-4) adiabatic or not, if so why are they the reason i ask is that i have a graph showing that these stages are adiabatic, however...

hey guys, just wanted to know, in the graph of the OTTO cycle in the link http://www.qrg.northwestern.edu/thermo/design-library/otto/Otto-Pv-diagram.gif are stage (2-3) and (1-4) adiabatic or not, if so why are they the reason i ask is that i have a graph showing that these stages are...

Just over half-way down this page:- http://www.embedded.com/columns/technicalinsights/220301380?cid=RSSfeed_embedded_news it says:- "These sunspot counts show variation on a cycle of roughly 11 years. By overlaying Oulu neutron measurements with sunspot count data since 1964, we see that...

Hi! I have trouble with the following: 1) Consider an ericsson cycle. It is easy to calculate the change of entropy of the working substance during the isothermal parts. But assuming that all the heat transferred/removed from the working substance during the isobaric processes is done by...

Homework Statement Write down cycle decompositions of all 24 of the rigid motions of the cube by regarding each rigid motion as a permutation of the 6 faces. Then, this is a subgroup of S_{6}, called S_{CUBE}. Prove or disprove that S_{CUBE} is a subgroup of A_{6} Homework Equations...

Ok bear with me as this sounds a bit bizarre, especially for a first post. For a while I have been thinking of how to take advantage of the fact that a black passive solar collector can collect low temp BTU's at low costs, but due to the low temperature it can not be utilized in a steam cycle...

The positive powers of 2 mod 5^m cycle with period 4*5^(m-1), which you can prove by showing that 2 is a primitive root mod powers of 5. I want to prove that the positive powers of two, mod 10^m, also cycle with this same period. How do I go from this powers of 5 result to powers of 10...

I discovered an eclipse cycle. It will be called the Wells cycle ( Garrick Wells ). It is simply a cycle of 51649 days. I believe that if you see an eclipse, then 51649 days later, another will likely be seen from your same location. I've have indeed found an example of this while probing the...

Homework Statement A power cycle has a thermal efficiency of 40% and generates electricity at a rate of 100 MW. The electricity is valued at $0.08 per kW * h. Based on the cost of fuel, the cost to supply Qin is $4.50 per GJ. For 8000 hours of operation annually, determine, in $. a. The...

I have been interested in atmospheric CO2 variance on geological time scales for sometime. There are multiple paradoxes associated with trying to explain what could cause massive cyclic rapid CO2 changes in the atmosphere. There appears to be multiple fundamental errors in terms of what is the...

THE PROBLEM: A three step-cycle of an ideal monoatomic gas (3.40 mol) undergoes an (1) increase in temperature from 200 to 500K at a constant volume, is then (2) adiabatically expanded back to it's original pressure, then is (3) contracted at a constant pressure back to it's original volume...

Hello all As anyone with a front-loading washing machine knows, watching them in action can be great entertainment. Well, I was bored tonight and did just that. During the final spin cycle, the drum spins really, really fast (not too sure how many rpm) to wring most of the water out of the...

Homework Statement General questions about how cancer affects the cell cycle... 1) Does cancer actually speed up the individual phases of mitosis (prophase, metaphase, anaphase, telophase) ... ie metaphase occurs 100x sooner following prophase in a cancer cell compared to a normal cell...

Hey. I'm supposed to calculate the work done in an adiabatic process, B-C, and I only know the values of the temperatures and the volume in the first point (point B). It is not known if it is a mono or diatomic gas, therefore i don't know the value of gamma. I've tried T*V^(gamma-1)=K and the...

Theoretically, we can have reversible isochoric expansion and isochoric compression. Is Otto Cycle reversible then? I read that the efficiency of all reversible engine between two heat reservoir would have the same efficiency. However, since the efficiency of an Otto Cycle is lower than...

the mud flies off the tyre of a moving motor cycle in the direction: -------------------------------------------------------------------------------- 1)towards the center of the wheel 2)towards the circular motion of the wheel 3)along the tangent to the wheel 4)away from the radius of...

Is it true that if \sigma \in S_n is a cycle of length k \leq n, then \sigma^k = \varepsilon, where \varepsilon is the identity permutation, and that k is the least nonzero integer having this property?

I found http://www.uoguelph.ca/~antoon/circ/wailing.htm" schematic for creating a siren sound, but I can't figure out which component could be altered to change the cycle time of 6 seconds. If I had to guess, I'd say either C1 or C4, but I'm really lost as to how this schematic works, so I...

When looking at a brayton cycle, how do you find enthalpies when your only given temperatures? This is not a homework question, just reading through the textbook and cannot see where got the value from? Thanks

I need to know how can I increase the duty cycle of a pwm. Thank you very much :)

A practical question about that cycle: I've just bought a new fridge and looked at the refrigeration cycle for the first time in 5 or so years. Now, i feel that the condenser at the back is quite warm (as it should be) and is being cooled by my room. All good and well. But how does the...

URGENT HELP NEED ! Engine cycle Question ! Q: Data on an engine cycle is presented.if the gas has a compression/expansion index of 1.4, determine the work done(KJ) in the cycle by theoratical and graphical means. compare your results. Given: Pressure in (Pa) p1= 1 X 105 p2= 11.764 X...

Homework Statement Here is the cycle: I am to assume cold-air standard applies. I need to: a)Draw a T-s diagram b)Find where heat is transferred and work is done c)Calculate the coefficient of performanceHomework Equations COP = 1 / (TH/TL - 1) The Attempt at a Solution For the T-s...

i want to ask why heat transfer is considered ti be an irreversibility and why in carnot carnot cycle heat addititon is at constant temperature to make this process reversible

Hey guys, can someone make things clear for me? Does the heart goes atrial systole followed by ventricle systole then followed by both the atrial and ventricle diastole (at once) or atrial systole, ventricle systole (at the same time atrial diastole) then only ventricle systole?

I am wondering where the phosphate needed to carry out the ATP cycle is derived from. Is it produced by our bodies, to we get it from the food we eat, or is eat based on a particular chemical reaction?

Homework Statement A heat engine takes 4.0 moles of an ideal gas through the reversible cycle abca, on the pV diagram, as shown. The path bc is an isothermal process. The temperature at c is 600 K and the volumes at a and c are 0.04 m^3 and 0.10m^3, respectively. The molar heat capacity at...

Homework Statement Analyze an air-standard Otto cycle assuming it is a cold cycle with properties evaluated at 300 K. Air intake and exhaust are at 300 K, 1 bar. After the combustion (heat in) process, the temperature is 2500K. The compression ratio is 9. The volume at bottom dead center...

Homework Statement Statement 1: Average value of AC over a complete cycle is always zero. Statement 2: Average value of AC is always defined over half cycle. We need to tell whether these two statements are right, and if 1 is right then whether 2 is its explanation. Homework...

Does anybody know what the pdf of a sine wave cycle is? Or perhaps how to derive it? The problem can be done numerically, but surely there is an analytic expression for this function? There is a numerical solution available at...

Is an ideal cycle possible? In a lab experiment that I have carried out, my enthalpy values for the cycle and the cycle assuming isentropic compression look like they are the same. I thought this was impossible but I am doubting myself now? Thanks Will

Homework Statement An ideal diatomic gas, in a cylinder with a moveable piston undergoes the rectangular cyclic process shown below. Assume that the temperature is always such that the translational and rotational degrees of freedom are active but the vibrational modes are "frozen out". Also...

The 1-2 ky climate cycle is clearly evident in the paleoclimate records and is of primary importance in future predictions. But what actually is the driving mechanism of this cycle? http://www.sciencemag.org/cgi/content/abstract/278/5341/1257

I was slightly exasperated with this http://www.sciencemag.org/cgi/content/abstract/289/5486/1897 report: "It is difficult to explain this predominant cycle in terms of orbital eccentricity because the 100,000-year radiation cycle (arising from eccentricity variations) is much too small in...

Hi posted the question/cry for help in a regular thread but thought it might fit in here as well. Hello All, I am currently trying to optimize a steam power plant cycle and I am stuck... What I am unable to figure out is how to use a Mollier chart/diagram in order to determine the amount of...

In the textbook, it reads: the reverse of carnot cycle is just a refrigerator or heat pump. In this sense, except for the direction of carnot cycle is reverse, could I say the way to calculate the efficiency of the carnot refrigerator is the same? That is, could be still use \eta = 1 -...

Homework Statement I must find temperature at each state, for starters. This is a Diesel cycle with a non-isentropic compression process, but standard the rest of the way. The specific heat is variable with temperature. Fluid is air Givens: compression efficiency (\eta_{c}), initial...

At what point in either beta-oxidation or citric acid cycle is ATP used? I see where ATP is produced in citric acid cycle (originally as GTP) as when succinyl CoA is converted to Succinate, but I can't find any part where ATP is required. Apparently according to my lecture notes, it is...

Where does the second water come from ? I get that the first one comes in the conversion of citrate to isocitrate, but where does 2nd one come in? thanks

Citric Acid Cycle --matching carbons Which glucose carbons are pyruvate carbons from? I've been trying to get this for hours. please help.. Also how do you trace carbons along the ciric acid cycle?

The idealized cycle shown is known as the Otto cycle. (Intro 1 figure) Suppose an engine is executing this Otto cycle, using a gas (not necessarily ideal) as its working substance. From state A to state B, the gas is allowed to expand adiabatically. (An adiabatic process is one in which no...

Bridging Step of Krebs Cycle...oxidatiion or reduction? I am told that the following reaction is a oxidative decarboxylation: pyruvate +CoA + NAD+ ---> acetyl CoA + CO2 + NADH but NAD+ is reduced to form NADH... Do we call it an oxidation because we are interested in what...

Homework Statement Set up thermodynamic cycle for determining the enthalpy of hydration of Mg2+ ions The following enthalpies are given Sublimation of Mg ionization energies of Mg dissociation enthalpy of Cl2 electron gain enthalpy of Cl enthalpy of solution of MgCl2(s) enhalpy of...

Hi All, I need some basic info of He closed cycle cryos..(like working principle, etc).. I have a compressor, which compress He gas and passed into a cryo's coldhead. So He gas expands in side the coldhead and cools the coldhead..then it again passes into compressor..so the cycle repeats.. I...

Homework Statement let a=(b_1,...,b_n) n-cycle in the permutation group S_n . prove that the cycle decomposition of a^k consist of gcd(n,k) cycles of n/gcd(n,k) size. The Attempt at a Solution I know that a^k(b_i)=b_{i+k (mod n)} how can it help me ?

A twin- spool turbojet powered aircraft flies at 600(ms-1) at an altitude where the temperature and pressure are 0.116bar and 216K. The air mass flow rate into the engine intake is 20kgs-1. The isentropic efficiences of the components are: intake (diffuser) 0.95; low pressure compressor: 0.92...

I am trying to come up with a design for a steam power cycle with a 40% thermal efficiency under the conditions that all turbines have isentropic efficiencies of 85% and all pumps have isentropic efficiencies of 60%. I have tried superheat, reheat, playing around with pressures/temperatures...