What is Correction: Definition and 202 Discussions

A correction fluid is an opaque, usually white fluid applied to paper to mask errors in text. Once dried, it can be handwritten or typed upon. It is typically packaged in small bottles, lids attached to brushes (or triangular pieces of foam) that dip into the fluid. The brush applies the fluid to the paper.
Less commonly, the fluid's fumes are inhaled to create dizziness, tachycardia and euphoria, sometimes producing adverse effects.
Before the invention of word processors, correction fluid greatly facilitated the production of typewritten documents. One of the first forms of correction fluid was invented in 1956 by American secretary Bette Nesmith Graham, founder of Liquid Paper. With the advent of colored paper stocks for office use, manufacturers began producing their fluids in various matching colors, particularly reds, blues and yellows.

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  1. K

    A Consistency check for Doppler correction calculations

    Hello! This should be an easy calculation, but I want to make sure as the result seems a bit weird. Say I have an individual atom, for which I know the energy with a given uncertainty. In my case say I have ##1000 \pm 2.5## eV. Lets say that I perform collinear spectroscopy on this atom (for...
  2. S

    I 1-loop Fermion mass correction in toy EFT

    Where does the ##m## in ##(3.2)## come from? It doesn’t seem to enter anywhere in Feynman rules for the given diagram
  3. dextercioby

    A First order electroweak correction to the g-2 magnetic moment

    We know that we need to go to 5th order in perturbation theory to match 10 decimals of g-2 for electron, theory vs. experiment. But let us not assume QED is pure and independent, but it's a lower energy limit of GSW (not Green-Schwartz-Witten from superstrings) electroweak theory. Has anyone...
  4. S

    A Why do we need a quantum correction for black hole entropy?

    Hey to all,... It is now generally believed that information is preserved in black-hole evaporation. This means that the predictions of quantum mechanics are correct whereas Hawking's original argument that relied on general relativity must be corrected. However, views differ as to how...
  5. F

    Engineering Find the reactive power before power factor correction

    Relevant Equations: My solution: Could someone please verify my answer?
  6. S

    Relativistic correction to Coulomb Potential in SQED

    I have derived the Coulombian potential as an effective potential between two spinless charged particle taking the non-relativitic approach on the scattering amplitude obtained in terms of the Feynman rules in SQED. The scattering amplitudes are: I'm using the gauge in which xi = 1. How could...
  7. Kaguro

    A Degenerate Perturbation Theory: Correction to the eigenstates

    Given the unperturbed Hamiltonian ##H^0## and a small perturbating potential V. We have solved the original problem and have gotten a set of eigenvectors and eigenvalues of ##H^0##, and, say, two are degenerate: $$ H^0 \ket a = E^0 \ket a$$ $$ H^0 \ket b = E^0 \ket b$$ Let's make them...
  8. Leo Liu

    Fixed gear ratio and correction tape

    I recently got a new correction tape. When I was staring at it today (ya I knew I should be studying for calc2), I noticed that the gear ratio between the two gears was notable and fixed. In particular, the bigger gear that unrolls the tape has more teeth than the smaller gear that rolls up the...
  9. S

    B Continuity correction when using normal as approximation for binomial

    What if the value of X is not integer, such as P(X < 1.2)? a) Will the continuity correction be P(X < 1.2 - 0.5) = P(X < 0.7)? or b) Will the continuity correction be P(X < 1.2 - 0.05) = P(X < 1.15)? or c) Something else? Thanks
  10. M

    Mass correction in ##\phi^4##-theory

    Before I start, let me say that I have looked into textbooks and I know this is a standard problem, but I just can't get the result right... My attempt goes as follows: We notice that the amplitude of this diagram is given by $$\begin{align*}K_2(p) &= \frac{i(-i...
  11. T

    Correction of horizontal astigmatism in an anamorphic lens

    Hello, I need advice which lens should I use for correction of horizontal astigmatism in anamorphics lens which contains two prisms. Focal length which I need to be focused is about 3 meters. I am using this prisms pair with projector. When I display grid horizontal lines are not focused...
  12. L

    Extinction correction (photometry)

    For example suppose the uncorrected extinction instrumental magnitude is ##v^A_V = 9.00##, will the corrected extinction instrumental magnitude always be greater than ##9##?
  13. S

    X error correction code in ProjectQ Python

    I have been trying write a code in for error correction. I am new to programming and am unable to understand what is not alright. Can anyone please suggest some explanation? from projectq.ops import All, CNOT, H, Measure, Rz, X, Z from projectq import MainEngine from projectq.meta import...
  14. electrogeek

    I 2nd Order Perturbation Theory Energy Correction

    Hi everyone, I'm struggling with the proof for the second order energy correction for perturbation theory when substituting in the first order wavefunction. I have attached an image of my current proof for it below, but I'm not sure whether this is the correct approach for it (the H's in the...
  15. Ennio

    I Velocity correction´ formula for the rotation of the Earth

    Let´s suppose we are observing the sun and measuring some spectral lines. Does the velocity correction´s formula for the Earth include the rotational velocity components of the Sun as well? or rather are we basically measuring both velocity contributes of Earth and of Sun together (receeding...
  16. N

    Calculation of g-factor correction in Peskin p. 196

    I'm reading peskin QFT textbook. In page 196 eq. (6.58) it says $$F_2(q^2=0)=\frac{\alpha}{2\pi}\int ^1_0 dx dy dz \delta (x+y+z-1) \frac{2m^2z(1-z)}{m^2(1-z)^2}\\=\frac{\alpha}{\pi}\int ^1_0 dz\int ^{1-z}_0 dy \frac{z}{1-z}=\frac{\alpha}{2\pi}$$ I confirmed the conversion from the first line...
  17. B

    Open pipe end correction distance for waves

    Struggling on how to do this Q I have tried drawing a sketch of it and had come up with this This is probably not right, as the speed of sound is not given here as well the length of the open pipe tube? Any help would be really great! Thanks
  18. AbdullahS

    Is Replacing a 25 kVAr Unit with Two 12.5 kVAr Units More Efficient?

    Hi all, The power factor correction unit for one of the buildings that I am working on needs maintenance. The service report recommends replacing the existing 25 kVAr unit with 2 x 12.5 kVAr units as "the demand on your site according to the data supplied shows us that at most there is only...
  19. Kaushik

    B Understanding Laplace's Correction and the Adiabatic Process

    Laplace pointed out that the variation in pressure happens continuously and quickly. As it happens quickly, there is no time for heat exchange. This makes it adiabatic. But Newton believed it to be isothermal. Why isn't it isothermal but adiabatic? Why is there a change in temperature?
  20. T

    Quantum 3-Qubit Error Correction Circuit

    Hello! I have this problem regarding the analysis of an error correction circuit. This problem set has been set for hand-in before the lectures regarding error-correction take place, so I am struggling. With that in mind I have read about the initialisation of the first qubit with two others...
  21. F

    A Computing sig8 for correction in non-linear regime

    I need to apply, with CAMB code, a correction on ##\sigma_{8}## between linear and non-linear regime to keep it fixed (I make change the values of cosmological parameters at each iteration). I have to compute ##\sigma_{8}## from the ##P_{k}## and found the following relation (I put also the text...
  22. Haorong Wu

    Second-order correction to energy in degenerate purturbation

    Let's focus on the degenerate case. Since in the subspace of the denegerate eigenvectors, ##H^{'}=\begin{pmatrix} -a & 0 \\ 0 &a \end{pmatrix}## is diagonal, then I treat ##\psi _2## and ##\psi _3## with the undegenerate perturbation theory. And I got ##E_2=E_2^0+\left < 2 \right | H^{'} \left...
  23. J

    Can Vector Analysis Help Find Replacement Weights for Spin Balance?

    I had a test article go through a spin balance service. The mass-radius and angular location of the correction weight, to achieve static and dynamic balance, interferes with another component on the test article (I'm unable to place the correction weight at the specified location). Using vector...
  24. Q

    A One Loop Correction to a 4 pt. function in 3 dimensions

    If I have a Lagrangian of the form \mathcal{L}=-\frac{1}{2} (\partial \phi)^2 - \frac{1}{2} m^2 \phi^2 - \frac{\lambda}{3!} \phi^6, in 3 dimensions, what is the one-loop correction to the 4-point function? Am I correct in thinking that the following Feynman diagram is the representation of the...
  25. C

    MHB What are the correcting words for matrices with equal integral entries?

    Dear Everyone, I am trying to figure what is the correct phrase in the bolden phrase. The article, where I am doing my research on, states: Let S be the set of all 2x2 matrices with equal positive integral entries. Let T be the set of all 2x2 matrices with equal integral entries. My professors...
  26. E

    First order perturbation energy correction to H-like atom

    Homework Statement Real atomic nuclei are not point charges, but can be approximated as a spherical distribution with radius ##R##, giving the potential $$ \phi(r) = \begin{cases} \frac{Ze}{R}(\frac{3}{2}-\frac{1}{2}\frac{r^2}{R^2}) &\quad r<R\\ \frac{Ze}{r} &\quad r>R \\...
  27. scottdave

    Other Correction to a book (magnetic compass)

    This article (in the picture) states that the end of a compass needle which points toward North is its south pole since the Earth's "magnet" has a North magnet at the North. But in reality, there is a south magnet pole (not sure about that terminology) near Earth's North Pole, attracting all...
  28. J

    A Is it possible that a particle is much heavier through a loop correction

    Let's assume, we have standard model singlet particle s that mixes after electroweak symmetry breaking with an exotic, vectorlike neutral lepton N The relevant part of the Lagrangian reads $$ L \supset h^c s N + h s N^c + M N N^c, $$ where h is the standard model higgs and M is a superheavy...
  29. S

    Correction to the field energy due to the existence of discrete charges

    In the classical electromagnetic field theory, the field density of energy is given by: $$u = (\epsilon/2)E^2 + (\mu/2)H^2$$ One of the differences between the classical electromagnetic theory and the real world is that in classical EM all charge and current density, (ρ(r), J(r)), is...
  30. C

    I (QED) The initial mass and the correction cancelling out

    The prefix is a bit irrelevant This is on renormalisation. How do they cancel out? Isn't it adding? So the mass experimental = m + (c2correction) so how do you cancel out the m and correction? I'm new to this area (just finished watching lectures by Richard Feynman, specifically a 4 lecture...
  31. T

    B Why does end correction in pipes change with radius

    This being WRT resonating pipes. Apparently the acoustical length of the pipe is different to the physical length due to the vibration of the sound particles moving the particles at the opening so that the physical length is no longer the length of resonance. I've found many sources on the...
  32. Leechie

    Using perturbation to calculate first order correction

    Homework Statement I'm trying to evaluate the following integral to calculate a first-order correction: $$\int_0^\infty R_{nl}(r)^* \delta \hat {\mathbf H} R_{nl}(r) r^2 dr$$ The problem states that ##b## is small compared to the Bohr radius ##a_o## Homework Equations I've been given...
  33. V

    Anharmonic oscillator first-order correction to energy

    Homework Statement I have ##H'=ax^3+bx^4##, and wish to find the general perturbed wave-functions. Homework Equations First-order correction to the wave-function is given by, $$\psi_n^{(1)}=\Sigma_{m\neq n}\frac{\langle\psi_m^{(0)}|H'|\psi_n^{(0)}\rangle}{n-m}|\psi_m^{(0)}\rangle.$$ The...
  34. P

    Extended or bit based Reed-Solomon error correction

    I am trying to find or develop an algorithm that can take a 1024 (lets assume random) bit array (so 128 bytes) and, by adding some redundancy (making the final code more than 1024 bits long), make it capable of decoding the data with up to n random bits flipped. Important point is that it has...
  35. T

    I Understanding Yates' correction

    I was studying Biostatistics by Zar, the Yates' correction part and stumbled upon this: My doubts: The conculsions are not taking place exactly at the level of alpha- what does this mean? Do the values of Chi square mentioned in table not correspond to the alpha(probability) indicated? Is...
  36. T

    I What is Yates' correction of contingency?

    I can't understand a word of https://en.wikipedia.org/wiki/Yates's_correction_for_continuity']Wikipedia.[/PLAIN] P.S. What I know so far is subtracting 0.5 from O-E if df=1 in Goodness of fit (?) is Yates' correction.
  37. R

    Power Factor Correction (open leg on a floating wye)

    We had a switch fail to close on the A phase of a floating wye connected capacitor bank. The C phase fuse was found to be bad and was replaced, however the B phase fuse then blew. The bad switch was then found and replaced. After that the system operated normally. The contractor said the...
  38. F

    A A question about the electron self-energy correction

    In QED, 'electron self energy' to first order results from an electron emitting and reabsorbing a photon. But surely the emitted photon can be absorbed by any other electron in the universe, not just the emitting electron? Indeed it makes no sense to say the photon is absorbed by the same...
  39. Mihai_B

    A Kerr-Newman Metric Correction from Einstein-Rosen

    Einstein (+Rosen) came to the conclusion that they have to change the sign for the energy tensor Tik : "if we had taken the usual sign for Tik, the solution would involve +ε2 instead of -ε2. It would then not be possible, by making a coordinate transformation, to obtain a solution free from...
  40. F

    Power factor correction (capacitor in parallel with inductive load)

    Why we must install capacitor in parallel to inductive load? Why not install it in series?
  41. R

    How Do You Calculate Capacitance for Unity Power Factor in a Single-Phase Motor?

    Homework Statement Not sure if this is the correct place for Electrical Engineering Homework help but here goes A single-phased motor connected across a 240-V source at 50Hz as shown in the figure has a power factor of 1.0, I = 20A, I1 = 25 A. Find the capacitance required to give a unity...
  42. saybrook1

    Bragg's Law with Refractive Correction

    Hi guys, the x-ray data booklet gives a modified Bragg's Law that seems to be a combination of Snell's and Braggs. I'll post a picture of what this looks like. I've tried combining the two equations and coming up with their answer but can't get a solid derivation. Any help or a point toward a...
  43. Schwarzschild90

    ND Pertubation theory: Second order correction

    Homework Statement Calculate the second-order correction to the ground-state energy of the stationary states of the system. The perturbed Hamiltonian is: H' =- (/gamma /hbar m /omega)/2 (a+ - a-) ^2 2 & 3. Relevant equatio and the attempt at a solution This is not right. I follow the same...
  44. JulienB

    Buoyancy correction in a Kater's pendulum

    Homework Statement Hi everybody! While preparing my next experiment (Kater's pendulum), I was given for homework to derive an equation to correct the buoyancy when calculating ##g##. I am given the result: ##g_c = (\frac{2 \pi}{T(\varphi_0)})^2 l_r (1 + \frac{\varphi_0^2}{8} +...
  45. W

    Hardy Cross method correction problem

    Homework Statement I have problem with the flow rate (Q) in junction that join 2 loops together , where k = 4 , Why in the second correction , the corrected Q in first and second loop = 21 clcockwise for left loop , and for 21 anticlockiwise for right loop ? Homework EquationsThe Attempt at a...
  46. Ali Durrani

    Is Using an Oxygen Rotameter for Propane Flow Measurement Accurate?

    Hello Dear friends i was doing tests to evaluate the performance of my Engine Test bench, (197/225cc engine 12.6kW IC SI engine, Propane) For mass flow rate i have used a rota meter to find the Volume flow rate and convert it to mass flow rate, i couldn't find a rotameter for propane so i...
  47. DjMadness

    Power Factor Correction for a small 60W AC Induction motor

    Hello, I have a light AC fan, that I wish to correct its power factor. According to my measurements, it has around 0.7 LAG power factor. Here are my digital measurements: Vsupply = 204VAC I(load) = 0.237Amps phi = 43 , pf = 0.7 LAG My target power factor (pf) is to be 0.85 , and to...
  48. astrof

    I De Broglie wavelength - relativistic correction

    According to the wiki page: http://en.wikipedia.org/wiki/Matter_wave the generalised form for the de Broglie wave is simply: \lambda = h/p I suppose this not correct, because there is no trasform which can change only one side of the equation. In this case we have two variables: 1. a momentum...