parts Definition and 838 Threads

In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, 10−6), parts-per-billion (ppb, 10−9), parts-per-trillion (ppt, 10−12) and parts-per-quadrillion (ppq, 10−15). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous.

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  1. T

    I Vector Triple Product Identity and Jacobi Identity for Deriving 4B.10 and 4B.11

    I was trying to derive the following results from 4B.8 as suggested by using the vector triple product identity but have been unsuccessful in deriving ##\vec{L_R}## and ##\vec{S_R}## in the end. After using the identity and finding the integrand to be ## \vec{E}(\vec{r}\cdot\vec{B}) - \vec{B}...
  2. Z

    Multibody Parts in Ansys Workbench

    Hello, can I have one simple question? I need create a Multibody Parts in Ansys Workbench. But I haven´t a Design Modeller. How do I create it? Thanks you. Pavel
  3. kostoglotov

    Buck regulator design, which parts can be slightly different?

    I want to build http://www.hobby-hour.com/electronics/lm2576hv-adj-buck-regulator-schematic.png From http://www.hobby-hour.com/electronics/lm2576-step-down-switching-regulator.php I might not be able to source exactly the same parts. I assume I have to use the same IC, but could I use a, say...
  4. Greg Bernhardt

    Who is donating body parts to science after death?

    I've been hearing of many athletes coming forward to donate their brains to science when they die. Curious with most of us being involved in science and its progress has anyone here made plans to donate their body or an organ to science after they die? Why not? Let's do it!
  5. G

    Find Parts for OrCAD Capture | Simple Diagrams

    Hi All, I am trying to make a simple diagram that uses some basic parts like switches, light bulbs, fuse holders, but I am having a difficulty finding these parts in OrCad Capture. Not sure if those parts are part of their libraries, or I need another program from that. The reason I am using...
  6. Lucas94

    Make a circle in square that is split 8x8 parts?

    Sorry if i may sound little unclear, english is not my first langue. I I am looking for a way to create a circle that is in a square cut in 8x8 in matlab. I would be glad if someone could give me a hand. Thanks!
  7. Guest312

    Optimizing Movable Joint Parts for Slider Crank Mechanisms

    I want to make a simple slider crank mechanism. I don't know what type of bolts or whatever is used for movable arms. I've heard online so far that using a carage bolt and nylon lock nut will work, but I bet there's probably other ways to make a movable joint. Something more secure. I'm sure...
  8. kyphysics

    News Good Lord, Lead Poisoning in Other Parts of Michigan Too

    https://www.yahoo.com/health/lead-poisoning-other-parts-michigan-222900551.html First, I actually lived in Michigan for 3.5 years (in Ann Arbor, Jackson and Ypsilanti), so I wonder if I could have been affected! Secondly, does lead poisoning only affect children? No teens/YA to full adults...
  9. E

    Integrate Laplacian operator by parts

    This is the key step to transform from position space Schrodinger equation to its counterpart in momentum space. How is the first equation transformed into 3.21? To be more specific, how to integral Laplacian term by parts?
  10. j3dwards

    Splitting function into odd and even parts

    Homework Statement Split the function f(x) = ex + πe−x into odd and even parts, and express your result in terms of cosh x and sinh x. Homework Equations f(x) = 0.5[f(x) + f(-x)] +0.5[f(x) - f(-x)] The Attempt at a Solution So i know that: ex = 0.5[ex - e-x] + 0.5[ex + e-x] = sinh(x) +...
  11. M

    MHB Integration by parts with absolute function

    Hi all, I have the average value of a function between limits of 7.3826 and 0 which equals 0.4453. I have used the formula for average value function and attached the equation I need solving as I don't know how to use the Latex commands. P is what I am trying to work out. Unfortunately I have...
  12. C

    Possible integration by parts?

    Homework Statement Integrate $$\int_0^1 dw \frac{w^{\epsilon+1} \ln((r+1-w)/r)}{1+r(1+w)}$$ for ##\epsilon## not necessarily an integer but positive and r is negative (<-1). The argument of the log is positive. Homework Equations Integration by parts The Attempt at a Solution [/B] I can...
  13. naima

    Integration by parts in curved space time

    In this thread, ramparts asked how integration by parts could be used in general relativity. suppose you have ##\int_M (\nabla^a \nabla_a f) g .Vol## Can it be written like ##\int_M (\nabla^a \nabla_a g) f .Vol## plus a boundary integration term (by integrating twice by parts)? I think thay it...
  14. naima

    Integration by parts in spacetime

    In this paper we have p18 an integral on space time M. The author takes a 3 dimensional space like Cauchy surface ##\Sigma## which separates M in two regions, the future and the past of ##\Sigma##. He gets so the sum of two integrals on these regions. He writes then let us integrate each of them...
  15. Philosophaie

    Integration by Parts: \int{\sin{(\theta)}*\cos{(\theta)}*d\theta}

    The Integral: \int{\sin{(\theta)}*\cos{(\theta)}*d\theta} Attempt to solve by Integration by Parts: \int{u*dv} = u*v - \int{v*du} u = \sin{(\theta)} du = \cos{(\theta)}*d\theta v = \sin{(\theta)} dv = \cos{(\theta)}*d\theta Bringing back to the beginning.
  16. Katiesunkissed

    Cell Parts: Understanding the Basic Components for Biology | Homework Help

    1. Homework Statement Homework EquationsThe Attempt at a Solution
  17. B

    Projectile Launching Question(multiple parts)

    Heres the Problem... A 2.0 kg object is launched from a 100 m tall cliff with an initial velocity of Vo=40m/s @ 30 degrees. There is a 40 m tall obstacle 200m from the base of the cliff. a)write initial velocity in "i,j" notation -I found this to be 34.64m/s i + 20m/s j = Vo b) how far above...
  18. Jabran Shakil

    Kinematics 1-D Problem. Stuck on specific parts.

    Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.1 m/s2 for 3.7 seconds. It then continues at a constant speed for 12.5 seconds, before applying the brakes such that the car’s speed decreases...
  19. Engineerbrah

    How Do You Integrate (x^(1/2))/ln(x) Using Integration by Parts?

    QUESTION: The question is to find the improper integral of (x^1/2)/lnx dx. MY ATTEMPT: 1)I tried it byparts, by taking 1/ln x as 'u' or the first function but i got stuck. 2)Alternatively, I tried substituting x=e^2t in hopes to eliminate ln for a simpler byparts integration, but that didn't...
  20. praveena

    How the satellite parts get damaged

    Hai PF, After a long time, I have again got a question now.The Mars rovers or other satellite body which is made of metal. My question is, when the rover or satellite land on the surface of Mars or moon does the metal experience any force on the body of the metal? Is there any...
  21. J

    Solving Parts E & F of Math Problem: Step-by-Step Guide

    Can someone help me how can I solve parts E and F ?
  22. MidgetDwarf

    Integration by parts Theory Problem?

    Find the second degree polynomial P(x) that has the following properties: (a) P(0)=1, (b) P'(0)=0, (c) the indefinite integral ∫P(x)dx/(x^3(x-1)^2). Note: the the indefinite integral is a rational function. Cannot have Log terms occurring in solution. first. I use the generic polynomial...
  23. Suraj M

    Integration by parts question help

    Homework Statement While integrating by parts( by the formula) why don't we consider the contant of integration for every integral in the equation. Homework Equations $$∫uv = u∫v - ∫ ∫v . d/dx(u) $$ The Attempt at a Solution [/B] example. $$∫x \sin(x) dx = ?? $$ this is can be done like...
  24. K

    Distance between surfaces in an assembly of sliding parts

    I have been working on designing something in SolidWorks for the first time, which involves several parts with surfaces that slide into one another. I am wondering if there is a table or a standardization in terms of the distance that should be left between metal surfaces with sliding parts. I...
  25. james gander

    How do we know quarks aren't just parts of broken-up protons

    Please be esy on me for asking what seems a very silly question but i have only just started reading about this sort of thing very recently. I can only learn by asking so please bear with me. thanks My question is, how do we know when we have found a new particle, for example when physicists...
  26. B

    MHB Integration by Parts: $\int u\cos(u)\,\mathrm{d}u$

    I have the following integral \int e(2x) cos(ex). Let u = ex Do integration by parts: \int u2cos(u) du = u2sin(u) - \int (2usin(u) du Do integration by parts again for \int (2usin(u) du: \int (2usin(u) du = -2ucos(u) - \int -2cos(u) du Putting it all together: \int e(2x) cos(ex) =...
  27. T

    Multi slot holder for milling round shaped parts

    Hello. I am a student and I got a task to design a 3D model for multi-slot holder for round shaped parts for milling operation. In the picture I attached there is shown a device that I should design, maybe improve it, but the problem is that a drawing is a bit unclear and I can't fully...
  28. S

    Integration by parts, just need a small hand

    Homework Statement I'm going to cut from the initial part of the problem, which I am confident is good to go, and cut straight to the antiderivatives. Homework Equations All antiderivatives are to be integrated on the interval from 0 to π/18 (I1) = -1/9 cos 9x - (I2) (-2/27 * cos3(9x)) + (I3)...
  29. Physics-UG

    Indefinite Integral with integration by parts

    Homework Statement Evaluate ∫e-θcos2θ dθ Homework Equations Integration by parts formula ∫udv = uv -∫vdu The Attempt at a Solution So in calc II we just started integration by parts and I'm doing one of the assignment problems. I know I need to do the integration by parts twice, but I've hit...
  30. T

    MHB Integrating $\cos(mx)$ with Two Variables

    \int x^2\cos(mx)\,dx When integrating this by parts, the $x^2$ will become the $u$ and the $\cos(mx)\,dx$ will become $dv$. How is the $\cos(mx)$ integrated if there are two variables?
  31. D

    How to integrate this by parts?

    Hey guys, So here's the issue I'm faced with. I need to integrate the following by parts (twice): \int d^{3}y\, e^{ik(\hat{n}_{0}-\hat{n})\cdot\vec{y}}\left[ \nabla\times\nabla\times\hat{\epsilon}_{0} \right] And I have absolutely no clue how to approach this. The result I'm meant to reach is...
  32. M

    Lathes - fits between different parts of a lathe

    Homework Statement Hey, so I've got an assignment for one of my MECH classes at uni where i am required to find the class of fit (clearance, transition or interference) between different parts of a lathe (i.e. spindle and spindle bearing, hand wheel and spindle etc.)I was wondering if anyone...
  33. karush

    MHB Integration by Parts with Domain Warning

    $\int x\ \cot^2\left({x}\right) dx $ $u=x$ $dv=\cot^2\left({x}\right) dx $ $du=\frac{x^2}{2}$ $v=\frac{-\cos\left({x}\right)+x\sin\left({x}\right)}{\sin\left({x}\right)}$
  34. Abtinnn

    A problem with Integration by Parts in Hartle's "Gravity"

    Hi guys! I am reading the book "Gravity" by Hartle. I came across this scary-looking integral. The author does integration by parts and I don't get how he does it. Could someone guide me please? Relevant equations: ∫u dv = uv - ∫v du
  35. DEvens

    What CAD program for complicated parts?

    What CAD program do people use and like? What programs use a standard data file format? It's ok if it requires me to pay. I have budget. But suggested good free programs are appreciated. What I am looking for is a CAD program to do 3D design of complicated parts. In particular, I am a nuclear...
  36. A

    Need Help Doing Integation by Parts

    Homework Statement Find the integral of z^3 e^z^2 Homework Equations The integration by part formula The Attempt at a Solution I have no idea what to do, I'm just turning in circles
  37. Peeter

    Integration by parts, changing vector to moment & divergence

    In Jackson's 'classical electrodynamics' he re-expresses a volume integral of a vector in terms of a moment like divergence: \begin{align}\int \mathbf{J} d^3 x = - \int \mathbf{x} ( \boldsymbol{\nabla} \cdot \mathbf{J} ) d^3 x\end{align} He calls this change "integration by parts". If this...
  38. J

    MHB Integration by Parts for Cosine Squared: Is My Approach Correct?

    Greetings :) Well I wanted to seek help if my solution is on the right path, given as follows: 1) \int cos ^2x dx So my solution follows like this: u = cos^2x du = 1/2 (1+cos(2x)) v = x dv = dx but I've stuck when its in the u.v - \int v.du cos^2 (x) - \int...
  39. C

    Can Plastic Gears Replace Metal in Industrial Machinery?

    Hello, I wonder whether I can replace the Metal gears and other parts with Plastic material? If so, what kind of plastic material should I use? There is no heat and the force is also not that great but the speed is. This is not for toy but industrial machinery, with gear diameter of about 10...
  40. M

    Integration by Parts: Does the Choice of u and dv Matter?

    Homework Statement $$ \int x^{3}cos(x^{2})dx$$ The attempt at a solution OK, so I am aware that there is a way in which to do this problem where you do a substitution (let $$u=x^{2}$$ to do a substitution before you integrate by parts), and I was able to get the answer right using this method...
  41. Filip Kierzek

    Probabilistic particle-scale valve with no moving parts

    Hi, Smoluchowski's trap door was proven to fail to obtaining work in a system without heat difference. The problem turns is random movement of trap door due to random particle movements. However I could not find any discussions of such system where the "trap door" did not involve moving parts...
  42. D

    Can a Stationary Alternator Generate Current Like a Transformer?

    will an alternator produce current when both its field and armature windings are stationary(like transformer action), as ac current produces a changing magnetic field.is the field rotated for making more output?
  43. B

    Which Integral Calculation is Correct?

    Homework Statement Which one is correct? ##\int (3x+2) (2x+1)^{\frac{1}{2}} dx = \frac{1}{3} (3x+2)(2x+1)^{\frac{3}{2}} - \frac{1}{15} (2x+1)^{\frac{5}{2}} + C## or ##\int (3x+2) (2x+1)^{\frac{1}{2}} dx = \frac{1}{3} (3x+2)(2x+1)^{\frac{3}{2}} - \frac{1}{5} (2x+1)^{\frac{5}{2}} + C## ...
  44. DivergentSpectrum

    Is the Alternative Method for Integration by Parts Simpler?

    I have a question why everyone says ∫uv' dx=uv-∫u'v dx why don't they replace v' with v and v with ∫vdx and say ∫uv dx=u∫vdx-∫(u'∫vdx) dx i think this form is a lot simpler because you can just plug in and calculate, the other form forces you to think backwards and is unnecessarily complicated.
  45. F

    MHB Integrate by making substitution and by parts

    I don't understand the question: "First make a substitution and then use integration by parts to evaluate the integral" \int sin \sqrt{x} dx What does it have in mind by "substitution"?
  46. M

    A space vehicle splitting into two parts (velocity question)

    Hi, so i have finished this question but I am not sure if I did it right. Could you guys check it and tell me if its right or show me where i went wrong. This is the question: A space vehicle traveling At a velocity of 1400m/s separates by a controlled explosion into two sections of mass 859kg...
  47. T

    Exploring Real & Imaginary Parts of Delbruck Scattering

    My question here involves Delbruck Scattering specifically but my curiosity is more general. Delbruck Scattering is the scattering of a photon off of the Coulomb field of a nucleus via the creation and annihilation of real and virtual electron-positron pairs. The process can occur at energies...
  48. L

    Is Integration by Parts Incorrect for ∫(x2 + 7x) cosx dx?

    ∫(x2 + 7x) cosx dx If I make v = (x2 + 7x) and du = cosx dx I get ((x2 + 7x) sinx)/2 If I make v = cosx and du = (x2 + 7x) dx I get ((x3/3 + 7x2/2) cosx)/2 using the form X=Y-X to X=Y/2 Neither are correct, what did I do wrong?
  49. M

    Compute causal function using integration by parts

    Homework Statement I stuck on, when the question as for integration by parts method. Need advice
  50. 8

    Integration by Parts: Solve ∫cos(x)cos(kx)dx

    Homework Statement Hello! I am having some trouble solving this integral by parts. I hope someone can help me. ##\int \cos(x)cos(kx) dx## It is need for a Fourier seriesHomework Equations I am using this definition: ##\int f(x)g(x) dx = f(x)G(x)-\int f'(x)G(x) dx## since its an even...
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