Cycles Definition and 158 Threads

  1. D

    What are the other types of geothermal cycles aside from dry, binary

    What are the other types of geothermal cycles aside from dry, binary and flash?
  2. H

    Mastering Cycle Conjugation: Essential Homework Tips and Strategies

    Homework Statement Homework Equations The Attempt at a Solution I honestly do not know how to start this.
  3. Y

    Where Can We Find Limit Cycles in Practical Machines?

    Where we can find Limit Cycles Phenomena in Practice, I mean in which class of machines?
  4. S

    Can an AC Water Well Pump Handle 50Hz Cycles for Use in Africa?

    I am new here and I am not really sure where to post this question. I am also not an Engineer, so general language would be appreciated. I sell Water Well Pumps at my location and on the Internet among other things. Today I had a call from a Man who wanted a Pump that was going to Africa. He...
  5. B

    Geometric Example of Torsion Cycles and Relative Cycles (in Homology)

    Hi, Everybody: I am trying to understand torsion and relative cycles in a more geometric way; I think I understand some of the machinery behind relative cycles (i.e., the LES, and the induced maps.), and I understand that by ,e .g., Poincare duality, in order to have torsion in...
  6. M

    Prove Odd Length Cycle u2 is Also a Cycle

    Homework Statement Show that for any cycle of odd length, u, then u2 is a cycle as well. Homework Equations The Attempt at a Solution I looked at examples of it and it does work them but I am unsure of how to generalize it.
  7. B

    How do I express an element in a matrix of s8 as a product of disjoint cycles?

    Homework Statement Express the element in matrix A= 1,2,3,4,5,6,7,8 4,1,3,2,8,5,6,7 of s8 as a product disjoint cycles [b]2. Homework Equations [/b The Attempt at a Solution I pick a number say the first 1 and pu it in parenthises. (1, I multiply by the number in th...
  8. D

    Why has the Holocene temperature cycle deviated from previous cycles?

    Reading a lot about climate change over the past few years has lead me to a question. From looking at the available temperature charts for the past 450K years I have become curious about the lack of comment on the deviation for the last 12K years from previous periodic 124K year peak...
  9. K

    Proving t a^-1 = b: Permutations & Cycles Homework

    Homework Statement Let t be an element of S be the cycle (1,2...k) of length k with k<=n. a) prove that if a is an element of S then ata^-1=(a(1),a(2),...,a(k)). Thus ata^-1 is a cycle of length k. b)let b be any cycle of length k. Prove there exists a permutation a an element of S such that...
  10. 1

    3-cycle or a product of three cycles permutations

    Homework Statement Show that every element in A(n)= set of even permutations, for n> or equal to 3 can be expressed as a 3-cycle or a product of three cycles. Homework Equations 3-cycle = (_ _ _). a permutation is a function from a set A to A that is bijective. The Attempt at a...
  11. marcus

    Cycles of time-Penrose says his cyclic cosmology obeys thermodynamics.

    Cycles of time--Penrose says his cyclic cosmology obeys thermodynamics. Roger Penrose has devised a cyclic cosmology which he sees as not violating the second law of thermodynamics. There are several online videos of him lecturing about it. I'll get some links. I'm curious to know if others...
  12. K

    Are There Quantum-Level Alternatives to Traditional Power Generation?

    I am plowing away through my ME curriculum and my intentions is to go into power engineering in some shape or form. I wanted to know if any research has gone into energy harvesting at a atomic level. I just wondered if any research has gone into alternative to a boiler and a turbine for...
  13. B

    Geometric description of (simplicial)homologous cycles

    Hi, everyone: I am trying to understand the geometric interpretation of two simplicial cycles being homologous to each other. Let C_k(X) be the k-th chain group in the simplicial complex X, and let c_k be a chain in C_k(X) The algebraic definition is clear: two...
  14. N

    Hamiltonian Systems: Showing Limit Cycles Impossible

    http://books.google.ca/books?id=Pd8-s6rOt_cC&pg=PA70&lpg=PA70&dq=%22show+that+in+a+hamiltonian+system+it+is+impossible+to+have+asymptotically%22&source=bl&ots=uJplwJKBPB&sig=4HBlny5uGifky2zfdNtWxDi-Uuo&hl=en&ei=yk6tS47hJJTssQOPvJmEDA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA...
  15. K

    How Do You Calculate the Efficiency of a Heat Cycle in Thermodynamics?

    Homework Statement One mole of an ideal monatamic gas at an initial volume of 25L follows the cycle shown below. All the processes are quasistatic. Find the efficiency of the cycle. Homework Equations PV = nRT dQ (at constant volume) = Cv*dT dQ (at constant pressure) = Cp*dT W(isothermal)...
  16. K

    Permutations and cycles - linear algebra

    Homework Statement Let \rho \inSym(n), p be prime, r be the remainder when n is divided by p (so 0\leqr<p and n=qp+r for some integer q). 1. Show that \rho^p = \iota iff the cycles of \rho all have lengths 1 or p. 2. Show that if \rho^p = \iota then |Supp(\rho)| is a multiple of p and...
  17. F

    How Does Conjugation Affect Cycles in Permutations?

    Homework Statement Let P be a permutation of a set. Show that P(i1i2...ir)P-1 = (P(i1)P(i2)...P(ir))Homework Equations N/A The Attempt at a Solution Since P is a permutation, it can be written as the product of cycles. So I figured that showing that the above equation holds for cycles will...
  18. F

    Does the Product of Cycles Hold for Permutations?

    Homework Statement Let P be a permutation of a set. Show that P(i1i2...ir)B-1 = (P(i1)P(i2)...P(ir)) Homework Equations N/A The Attempt at a Solution Since P is a permutation, it can be written as the product of cycles. So I figured that showing that the above equation holds...
  19. R

    Supergalactic cluster waves and geological cycles

    In large scale surveys of the Universe there are found to be huge megawalls of galaxies. A 128 Mpc/h periodicity in galaxy redshifts is observed by Tom Broadhurst, Richard Ellis, David Koo and Alex Szalay, in Nature vol 343 p726. Some cosmologists have suggested that this might be some sort of...
  20. K

    At the end of these 100,000 year cycles of temperature, what causes

    at the end of these 100,000 year cycles of temperature, what causes the peak temperature to fall?
  21. C

    Hello. Needs help with disjoint cycles.

    Express as the product of disjoint cycles: a. (1,2,3)(4,5)(1,6,7,8,9)(1,5) b. (1,2)(1,2,3)(1,2) I now how to do in 2 row permutations, with right to - left. can anyone tell me , how to express it without transfer it into 2 row permutations. One more question, How do we find out it's...
  22. T

    Isobarric, Isochoric, Adiabatic cycles

    Homework Statement Ok, i have a cycle that goes from "a to b", via isobaric expansion, than from "b to c" vis isochoric decrease in pressure, and "c to a" via a adiabatic compression. Each occur under quasistatic conditions I just want to double check I've got the, changes in work, heat...
  23. D

    Representing products as disjoint cycles

    Homework Statement Represent the following products as products of disjoint cycle. find the order of each product. Homework Equations a) (1234)(567)(261)(47) b) (12345)(67)(1357)(163) c) (14)(123)(45)(14) The Attempt at a Solution I've only attempted a) because I'm not sure...
  24. Mk

    Supernovae and solar cycles found in Ice Cores

    http://arxiv.org/abs/0902.3446 So apparently gamma rays from nearby supernovae produce nitrogen oxide in the atmosphere. The team took 122-meter-long cores from Dome Fuji station in Antarctica and found three nitrogen oxide spikes in the 11th century. They think they know what two of them are...
  25. C

    Entropy for reversible and irreversible cycles.

    I am confused about the entropy change for reversible and irreversible cycles. I know entropy is a state function, so for cycles, the entropy change within the system should be 0, since the process ends up in the same state as the beginning. So does this mean that the entropy change for the...
  26. N

    Continental drift: effect on climate cycles

    I'd be interested in any ideas or theories or references on how the location of the continents is thought to affect global warming and cooling cycles. I previously read somewhere that the current position of the continents would cause different net solar heat absorption/reflection than prior...
  27. X

    Question about permutation cycles

    If A is a cycle, and A=(1 4 5) (2 3 6). Is there a B such that BAB^-1=A^2. I found A^2=(1 5 4) (2 6 3), but I'm not really sure where to go from there.
  28. A

    How Can I Compare the Efficiencies of Ideal Diesel, Otto, and Dual Cycles?

    I want to compare the Ideal Diesel, Otto and Dual cycles with constant specific heats. I am interested in knowing the relationship between r (compression) and nth (efficiency). I am unable to determine the common inputs to all three which can give me the efficiency for all the cycles. r with...
  29. D

    Two Closed Thermodynamic Cycles Conceptual Question

    Imagine processing the gas clockwise through Cycle 1 and then counterclockwise through Cycle 1. Compare these two processes on the basis of the heat energy transferred to the gas in the entire cycle. Choose the correct comparison symbol. Q_clockwise for Cycle 1 <,=,> Q_counterclockwise for...
  30. P

    Can a permutation with non-disjoint cycles still be used to find its order?

    i am pretty sure it's true that to find the order of a permutation, you can find LCM of the length of the disjoint cycles... if you have a permutation that doesn't have disjoint cycles (i.e. like one with (1,3,6,8)(4,6)), then can you use the same method to find the order? I feel like I am...
  31. S

    Counting cycles in a permutation

    I'm trying to show that for two permutations f ang g in Sn, the number of disjoint cycles in fg is the same as the number of disjoint cycles in gf. I know that in general fg does not equal gf, but by working examples it seems like they always decompose into the same number of disjoint cycles...
  32. A

    Expressing as Product of Disjoint Cycles

    Homework Statement Express as the product of disjoint cycles: a. (1,2,3)(4,5)(1,6,7,8,9)(1,5) b. (1,2)(1,2,3)(1,2) The Attempt at a Solution a. (1, 2, 3) ( 4, 5, 6, 7, 8, 9) b. (1, 2, 3) These are the answers I got directly through the product. Would anybody be willing to check...
  33. D

    Sleep cycles, circadian rythms, etc

    On all those studies which took people and placed them in caves/prolonged darkness, it's known the body goes into a 25 hour "day/night cycle". But is that cycle itself roughly synced with the actual day and night (even when the person can't tell whether it's day or night outside), and if so, how...
  34. R

    Problem Dealing with Digit Cycles

    Not sure if cycle is the best word here.. Let k and b (both > 1) be such that b does not divide k-1 (with the exception that b may equal k-1). If n is the smallest power so that k^n is equivalent to 1 mod b (so n is the length of the digit cycle of 1/b in base k), then bn is the...
  35. Andre

    What Causes 430,000 Year Cycles in Paleocene Sea Level?

    We have discussed sea level yoyo's from the Pleistocene ice age of which it is suggested that it balances with the ice volume paced on the poles. So all of a sudden a study pops up (courtesy of the author), Dr Madeleine Briskin...
  36. C

    What are the approximate costs for operations on common x86 chips?

    As a first step to optimizing code, I like to think about faster ways to do things. Algorithmic improvements are far better than minute improvements to code, or even use of inline assembly, in general. But most optimizations beyond common subroutine elimination and its ilk substitute...
  37. S

    Multiplying non-disjoint permutation cycles

    Maybe I'm just being dense, but I've been having issues with the multiplying non-disjoint permutation cycles (as you may have guessed from the topic title). Simple products like (1, 4, 5, 6)(2, 1, 5) [an example from my textbook], as well as in the opposite order. Mayhap that I'm tired...
  38. R

    What Are the Pros and Cons of Using Nitrogen vs Helium in PBMR Cooling?

    I would need help, if there is someone willing to help... Q: ·What are advantages and disadvantages of nitrogen as cooling gas in PBMR comparing with helium? ·On witch way is possible to increase power of Brayton cycle to act on compressor side and in the same time greatest pressure...
  39. M

    Cycles per instruction question, why different CPI when I change for loop order?

    Hello everyone, this is a computer science/computer engineering problem... I had the following file that multiplies 2 matrices together, with 100 elements and puts it into a 3rd 100 element matrix. Well I used Simple Scalar to anlayize the CPI generated by the code and it also records the miss...
  40. 0

    Check for Cycles in Undirected Graphs: O(|V|) Algorithm

    I'm just posting a random graph algorithm problem for discussion fodder, since another interesting graph algorithm post was removed due to a threatening-sounding title and lead-up. This is from Cormen, Leiserson, Rivest, & Stein, 22.4-3 (not a homework problem of any kind, just for fun--I had...
  41. E

    What is the significance of the sopfr function in these cycles?

    I posted this in another math forum, but have received no response: Let sopfr(n) be the sum of prime factors of n (see http://mathworld.wolfram.com/SumofPrimeFactors.html ). There have been observations that certain iterations involving the sopfr function seem to lead invariably to cycles...
  42. S

    What Are the Expansive and Contractive Cycles of the Universe?

    Hi guys, I've been working on a theory for a bit and am wondering what you guys think. So here it is: Summary The universe expands through the expansive era. Then it contracts through the contracton era. The universe contracts until it finally collides in the center of the universe. This...
  43. R

    Earth's Rotation: Day & Year Cycles

    Which way does the Earth rotate and why? I am talking about both of the rotations. Rotation for a day and a rotation for an year.
  44. R

    Is Cp Used Only for Processes with Flow Work in Power Cycles?

    do we use Cp just for processes with flow work or ther is anything more related with this, is my question thanks for ur help..
  45. B

    How to Quickly Converge to a Limit Cycle in Higher Order Systems?

    Help. If anybody knows them beyond introductory level... i have a higher order system with a single fixed point. i chose such parameters that the fixed point is unstable. so it should either oscillate to infinity, or in this case it actually has a limit cycle. when running this system on the...
  46. C

    Powers of cycles? Orders of elements?

    When calculating powers of cycles, are there any easy steps to use in doing so? I mean...is there a typical relationship when calculating (123)^n? Also, is it safe to say that a ceratin n-cycle should have order n or n-1? I guess any explanation of orders for group elements would be...
  47. A

    Cycles of Matter: Carbon-Oxygen Cycle & Photosynthesis/Respiration

    In the carbon-oxygen cycle how does the process of photosynthesis and respiration interconnect? what pathways does a carbon atom go tom a fossil fuel to becoming a part of air that a person can exhale?
  48. Chi Meson

    Unbelievable Rainbow Phenomenon: 4 Cycles of Color!

    Last evening there was the perfect rainbow condition: A bright evening sun shining into a rainstorm just overhead. I went outside to see both complete arcs from horizon to horizon . THen... the inner rainbow (the most commonly seen rainbow, with red on the outside of the bow) looked odd...
  49. I

    Efficiency of an infinite series of Carnot cycles

    Dear people of Physics Forums, I would like to have your opinion about the following problem: Suppose we are interested to evaluate the average efficiency ( e ) of an infinite series of carnot cycles. The temperature of the hot reservoir of each carnot Cycle of the series, Ta, is at 990K, but...
  50. Oxymoron

    How Do Permutations and Conjugacy Classes Operate in Symmetric Groups?

    Question Let S_n be the symmetric group on n letters. (i) Show that if \sigma = (x_1,\dots,x_k) is a cycle and \phi \in S_n then \phi\sigma\phi^{-1} = (\phi(x_1),\dots,\phi(x_k)) (ii) Show that the congujacy class of a permutation \sigma \in S_n consists of all permutations in S_n...
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