Scale Definition and 743 Threads

The Southern California Linux Expo (SCALE) is an annual Linux, open source and free software conference held in Los Angeles, California, since 2002. Despite having Linux in its name, SCALE covers all open source operating systems and software. It is a volunteer-run event.
The event features an expo floor with both commercial and non-profit exhibitors, as well as 4 days of seminars on the topic of Linux and Open Source software. Sessions and presentations cover a broad spectrum of topics and technical levels.
SCALE grew out of a series of LUGFests put on by the Simi Conejo Linux Users Group in the late 90s. There were four of them, held every 6 months at the Nortel development facility in Simi Valley, California. They ended when Nortel closed that facility in 2001. Subsequently, members from SCLUG, USCLUG and UCLALUG organized to create a more regional event, which they named the Southern California Linux Expo.
Companies, organizations and projects represented at SCALE include Linux-based projects such as Debian, Gentoo Linux, the Fedora Project, KDE and GNOME, other open-source operating systems including NetBSD and FreeBSD, software projects such as Django, open-source database systems such as MySQL and PostgreSQL, other open-source applications such as Drupal, Inkscape, MythTV and The Document Foundation, activist organizations such as Software Freedom Law Center and the Electronic Frontier Foundation, major technology companies such as IBM, HP and Sharp, web companies including Google, Facebook and eHarmony, and internet projects including OpenStreetMap.

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  1. C

    Intuition Behind Scale Invariance Power Spectrum

    In the book "Statistical physics for cosmic structures" at p. 171 a read a definition of scale invariance (leading to the so called scale invariant power spectrum) given as the requirement that ##\sigma^2_M(R=R_H(t)) = constant##, where ##R_H(t)## is the horizon, i.e. the maximal distance that...
  2. M

    MHB Calculate % Increase from Scale Factor: Stumped? Help Here!

    Hi guys, This question has me a bit stumped and I can't seem to find any methods on Google that would help me solve this: The last part of the question asks me to find the value of the scale factor, which in this equation I believe is 1.8. I know how to calculate percentage increases the...
  3. marcus

    The naturalness of the zeon length scale

    Wabbit had an interesting comment in the "Aeon to Zeon" cosmology thread. Here's an excerpt, for more follow the link. I replied saying I'd start a separate thread.
  4. B

    What is the concept of scale invariance in quantum field theory?

    Hey guys! I was reading the following paper http://arxiv.org/abs/hep-ph/0703260 for Georgi and I have a conceptual question about it. Howard Georgi was talking about this Unparticle Physics theory and at the base of his analysis is the principle of scale invariance. So Georgi is saying what if...
  5. L

    Object sliding down a block on a scale

    Homework Statement A 200g hamster sits on an 800 g wedge shaped block which in turn rests on a spring scale. An extra fine lubricating oil is sprayed on the top surface of the block, rendering it entirely frictionless, causing the hamster to slide down. Friction between the block and the scale...
  6. U

    How do I find the scale factor of cosmological constant?

    Homework Statement (a)Sketch how the contributions change with time (b)For no cosmological constant, how long will this universe exist? (c)How far would a photon travel in this metric? (d)Find particular density ##\rho_E## and scale factor (e)How would this universe evolve?[/B] Homework...
  7. Rajkovic

    Touching at atomic and macro scale

    I asked a question here in the forum, in the topic "Many Worlds Interpretation", things do touch in atomic scale? and in the macro scale? what defines "touching" ? Some members answered me.. Rodrigo Cesar said: in this video: watch?v=P0TNJrTlbBQ Professor Philip Moriarty explains it perfectly...
  8. M

    How Is the Scale Factor R(t)/R(0) Calculated in Cosmology?

    Homework Statement The energy density of the universe for radiation, matter and cosmological constant have changed over the years and there was a time (t), when it was equal for matter and radiation. Assuming the universe is 13.7 billion years old, estimate R(t) / R(0) where R(0) is the...
  9. maboomba

    Quantum Bose Einstein effects on a macro scale?

    If say a hundred or more objects, at a human scale, are connected by a string, and they can be made to synchronize in an oscillation, could that be considered a bose einstein condensate?
  10. ognik

    Orthogonal coordinate systems - scale factors

    Homework Statement Start from the 'relevant equation' below and derive $$ (1) \frac{\partial{\bf{\hat{q}}_{i}}}{{\partial{q}}_{j}}={\hat{q}}_{i}\frac{1}{{h}_{i}} \frac{\partial{h}_{i}}{{\partial{q}}_{j}}, {i}\ne{j}$$ $$ (2) \frac{\partial{\bf{\hat{q}}_{i}}}{{\partial{q}}_{i}}= -\sum...
  11. R

    Is Faraday's law applicable on a lesser scale?

    Farraday's law tells us a magnet traveling through a solenoid will induce a current. It is understood electromagnetic properties and magnetic properties are somewhat interchangeable, and this allows magnets to move electrons in the wire. Can it then be inferred that an electron moving through a...
  12. Evo

    Indian parents scale new heights to help kids cheat

    Unbelievable cheating in Indian schools. http://www.cnn.com/videos/world/2015/03/20/pkg-walker-india-student-cheating-scandal.cnn
  13. ognik

    MHB General orthogonal scale factor identity

    Please be patient as I struggle with latex here ... Part 1 of the problem says to start with: $ \frac{\partial\bar{r}}{\partial{q}_{1}} ={h}_{1} \hat{q}_{1} $ and then to find an expression for $ {h}_{1} $ that agrees with $ {g}_{ij}=\sum_{l}...
  14. slatts

    Scale of perturbations re entropy, in quantum bounce

    In Bojowald's 2010 popularization of Loop Quantum Cosmology Once Before Time, there's a sketchy diagram (on his p.125) showing quantum perturbations in a transitional phase between contracting and expanding universes as widest at earlier times of decreasing volume, narrowing at the...
  15. M

    Graph Scale Confusion: Estimating Values from Plots

    Hello, I have to estimate some values from a plot (shown in the attachment). The trouble is I'm not sure how to read one of the scales could someone please explain the nature of the scale along the top frame, the angular scale, i.e how it is spaced. One of my aims is to estimate which angle...
  16. A

    Does a scale *display* weight or mass?

    I know that scales measure weight (a force) via displacement of a spring. I also know the difference between a force and a mass. I know that, on the moon, the numbers on a scale might be different (depending on the answer to this question). I've read through the few threads on this matter here...
  17. P

    Calibration cosmic distance scale on age globular clusters

    Hi, Could someone enlighten me in this matter? . how the calibration of cosmic distance scale affects the determination of the age of globular star clusters? thanks a lot :)
  18. Manta173

    Small scale application of structural cross sections

    I am working on fixing a heavy walnut cedar chest lid that has bowed convexly from the chest. It is about 1/4" high in the center of a 24" deep lid. The lid is ~2' x 5'. It is made from 3/4" walnut with 3/4" x 3" ribbing on the top. I thought that adding in some C-channel or square tubing would...
  19. Einj

    Fixed point and scale invariance

    Hello everyone. I'm studying the fixed point of theory in the context of QFT. First of all, let me say what I think I understood about fixed points and then I'll state my question. Suppose we have a theory with a certain running coupling ##\lambda(\mu)##. If we have, for example, an UV fixed...
  20. P

    Weighing with A 400 N Scale and 80 N Spring Dynamometer

    Homework Statement A former student of mechanics wishes to weigh himself but has access only to a scale A with capacity limited to 400 N and a small 80 N spring dynamometer B. With the rig shown he discovers that when he exerts a pull on the rope so that B registers 76 N, the scale A reads 268...
  21. Digitalism

    Scale Symmetry: Resources, People, History

    Hello, I am looking for resources on scale symmetry including the persons who are at the forefront, arxiv preprints, history of the development of the idea, and any other sources you can think of. Thank you.
  22. G

    Chain Falling on a Scale: What is the Reading?

    Homework Statement A chain of mass M and length l is suspended vertically with its lowest end touching a scale. The chain is released and falls onto the scale. What is the reading of the scale when a length of chain, x, has fallen? (Neglect the size of individual links.) Homework Equations...
  23. J

    The elevator, the scale, and the wrong answer: Solving the Puzzle

    You walk into an elevator, step on a scale, and push the "up" button. You recall that your normal weight is 625N. If the elevator has an acceleration of magnitude 2.50 m/s^2, what does the scale read? I know how to solve this problem, but I don't know why I'm getting the wrong answer. I first...
  24. P

    Velocity of receding galaxies. Hubble <-> scale factor

    Hi there, This is my first post but I've been a spectator for a long time now. So I've been working on some of the basics of cosmic expansion and there is one contradiction that I came upon that I can't seem to resolve. I've looked around some of the similar threads but I couldn't find anything...
  25. Sivasakthi

    Choosing appropriate length scale in condensed matter

    Hi.. I was reading some papers on continuum dynamics and its application to various material dynamics. The determination of macroscopic behavior is being studied , considering phononic interactions. As a material consists of phonons of various wavelengths, it is necessary to account for various...
  26. F

    Exploring the Potential of Quantum Tunneling Composites for Load Cell Technology

    Is it possible to build a fast, accurate scale using QTC? If so, could someone explain the basics or point me toward a good resource? Thanks!
  27. binbagsss

    GR: FRW Metric relation between the scale factor & curvature

    Mod note: OP warned about not using the homework template. I have read that 'a(t) determines the value of the constant spatial curvature'.. Where a(t) is the scale factor, and we must have constant spatial curvature - this can be deduced from the isotropic at every point assumption. I'm trying...
  28. S

    Scale invaraince of renormalisation theory

    Hi, I was wondering if anyone could refer me to a journal article that talks about the scale symmetric properties of renormalisation theory in the context of simple quantum-mechanical system governed by a delta function potential.
  29. A

    Matching Reynolds Number in Scale Model Wind Tunnel Testing

    For my senior design project, I have to reduce the aerodynamic drag of a truck and trailer. I am doing CFD simulations and wind tunnel testing. The dimensions of the wind tunnel (test section) are 94 in long, 13.5 in tall and 20 in wide and a cross-sectional area of 270 in^2 and it could go up...
  30. T

    Parity violation on macroscopic scale

    a question which is bugging me... Yes, I know that parity is violated only by the Weak Interaction, which is very short range. So I would answer "no, there is no P violation on macroscopic scale" However, many macroscopic properties are the results of what happens on the microscopic level. So...
  31. TrickyDicky

    The scale factor in flat FRW model

    In the FRW model with Euclidean 3-space, k=0 in the first Friedmann equation makes the density(times a constant) directly related to the Hubble parameter. The Hubble parameter is the time derivative of the scale factor divided by the scale factor itself. My question is: does a Euclidean...
  32. Y

    Calibrate Scale: Sliding Weights Not Springs

    I have a scale, the kind for weighing people, and I'm trying to calibrate it. It uses sliding weights, not springs. You step on the scale and then slide the two weights along the beam until it balances. Suppose I keep the smaller weight at zero and slide the larger weight to the 50-pound mark...
  33. V

    Understanding Planck Scale Derivation: Energy, Length, and Uncertainty

    I see that Planck scale of mass-energy is related to the corresponding length scale by application of the uncertainty principle. What is not clear for me is how we find either energy or length scale to compute the other one? What goes wrong if we assume a higher energy level than the Planck...
  34. R

    Difference between the absolute thermodynamic temperature scale and ITS-90

    Homework Statement What is the difference between the absolute thermodynamic temperature scale and the practical temperature scale: ITS-90? Homework EquationsThe Attempt at a Solution
  35. J

    A Large scale eigenvalue problem solver

    Hi, I'm wondering what eigenvalue problem solver you are using? I'm looking for an one which could solve a very large eigenvalue problem, the matrices being ~ 100,000*100,000. Do you have any advices? Thanks.
  36. B

    Scale in an elevator, time, mass, and velocity function given

    Homework Statement You are standing on a bathroom scale in an elevator in a small building. The elevator starts from rest and moves with a velocity given by v(t) = (3 m/s^2)t + (0.2 m/s^3)t^2. If your mass is 64 kg what is your weight at t=4.0 s as recorded by the scale (in N) Homework...
  37. nomadreid

    Assigning a Size to Particles and Strings: From Planck Scale to the Universe

    Except for associating a statistical mean to a large number of measurements, how can one assign a single point to a particle ? Indeed, how can one assign a size of anything less than the Planck scale? A similar question about strings: how can one talk about one-dimensional objects? A similar...
  38. C

    What Are Characteristic Scale Arguments in Physics?

    In physics one often invokes arguments about a characteristic scale. For example at distances much larger than the Compton wavelength (a characteristic length scale) one might ignore quantum phenomena and calculate classically. I would like to read up some more on the thinking behind such...
  39. minimario

    Child, Chair, and Spring Scale on Pulley: Forces

    Homework Statement Homework Equations $F=ma$ The Attempt at a Solution (a) Because the spring scale weighs 250 N, the effective weight on the child's side is 230 N. Therefore, $T-230 = \frac{230}{9.8} a$ and $T-250 = -\frac{250}{9.8} a$, so $a = 0.408$. This is correct, but is the...
  40. C

    Validity of the Pauling Scale of Electronegativity?

    I propose the Pauling Scale is not valid in all circumstances, and other scales of electronegativity would do better to predict the behavior of electron density in molecules: Electronegativity seems to be poorly defined for such a widely used chemical property: a 'tendency' of an atom or...
  41. B0b-A

    What's the scale on Mars rover "Microscopic Imager" images ?

    What's the scale on Mars rover Opportunity's "Microscopic Imager" images ? I'm trying to work out if the Martian "fossil" shown could be the impression of a cross-head-screw ... http://mars.jpl.nasa.gov/mer/gallery/all/1/m/3720/1M458433044EFFCEQKP2955M2M1.HTML
  42. T

    Digital scale > laptop data transfer help?

    I wonder how can I get the data recorded on a scale be transferred onto a laptop directly? forexample, I need a curve in the change in weight of something in the past minute, I am looking forward to at least one measurement per second, preferably 10 per second or much higher. The recorded data...
  43. A

    Automotive How to calculat fronatl area of scale car

    Hello guys, I am doing a wind tunnel and I want to calculate the aerodynamic coefficient of some cars. To calculate this I need the frontal area of the car and I don't know how to calculate it manual. Is there any pc program to do it or any formula? Thank you very much.
  44. I_am_learning

    Finding a Precise Scale for Measuring Human Body Weight Fluctuations

    I was lately interested in learning how the human body weight changes through out the day. Like, how much weight (may be in just 10s of grams) is lost during sleeping, after bathing, after workout and like that. For that I would require a highly precise scale. But most commercially available...
  45. S

    Are Small-Scale Fusion Reactors the Future of Electric Power?

    Do you know of any promising concepts for small scale fusion reactors (for electric power production)? I'm thinking of something the size of, say, a train car or even smaller.
  46. M

    How to scale a logistic equation to become dimensionless?

    Homework Statement I have an equation: dN/dt = N(r-a(N-b)^2) where r,a,b>0 are constants and I need to scale it to the dimensionless form dn/dtao=n(1-a(n-1)^2), however, I tried many ways and I am still unable to get it into the form. The question also suggests using n=N/c and tao=t/d as a...
  47. D

    Converting Pressure to Power in a Scale Model Boat

    I have built a model boat, ( http://schoolroad.weebly.com/rpgmodel_11.html ) and am trying to find out the amount of Power - maybe in Watts, that it takes to propel it at different speeds while it is running on the water. I have a rough sketch of the mechanism principle attached. When the...
  48. TrickyDicky

    Renormalization and scale dependence

    Since Wilson work in the 70s, the renormalization technique in QFT is physically justified with the concept of scale dependence(scale anomaly) of the parameters. This apparently is akin to a universal version of the characteristic length usually applied to specific physical systems to define...
  49. jdawg

    What Went Wrong with This Linear Temperature Scale Problem?

    Homework Statement I'm not sure what I'm doing wrong on this problem! Please help :) Suppose that on a linear temperature scale X, water boils at -40.0°X and freezes at -174°X. What is a temperature of 146 K on the X scale? (Approximate water's boiling point as 373 K.) Homework...
  50. C

    Ph Scale Logarithms: Calculating Acidity Difference

    How do I work out how many times more acidic a ph value of 6.8 is compared to 8.6? For example.
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