What is Separation: Definition and 475 Discussions

A separation process is a method that converts a mixture or solution of chemical substances into two or more distinct product mixtures. At least one of results of the separation is enriched in one or more of the source mixture's constituents. In some cases, a separation may fully divide the mixture into pure constituents. Separations exploit differences in chemical properties or physical properties (such as size, shape, mass, density, or chemical affinity) between the constituents of a mixture.
Processes are often classified according to the particular differences they use to achieve separation. If no single difference can be used to accomplish the desired separation, multiple operations can often be combined to achieve the desired end.
With a few exceptions, elements or compounds exist in nature in an impure state. Often these raw materials must go through a separation before they can be put to productive use, making separation techniques essential for the modern industrial economy.
The purpose of separation may be analytical, can be used as a lie component in the original mixture without any attempt to save the fractions, or maybe preparative, i.e. to "prepare" fractions or samples of the components that can be saved. The separation can be done on a small scale, effectively a laboratory scale for analytical or preparative purposes, or on a large scale, effectively an industrial scale for preparative purposes, or on some intermediate scale.

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  1. K

    Finding Highest Order Node & Antinode: Source Separation d & λ

    Homework Statement if i have source separation between 2 light sources, d, and wavelength, λ, what is the highest order node and antinode? Homework Equations The Attempt at a Solution im not sure where to start for this question I am leaning towards division to cancel out the meters
  2. B

    How to Solve a Differential Equation Using Separation of Variables

    Homework Statement use separation of variables to solve the differential equation x^2dy/dx=y-xy with the initial condition of y(-1)=-1 Homework Equations The Attempt at a Solution after i separated and integrated i got the answer y=e^(-1/x-lnx+c) the answer in the book is y=e^-(1+1/x)/x i...
  3. D

    Modeling Population Growth Using Separation of Variables

    \displaystyle\frac{dN}{dt} = rN\left(1-\frac{N}{K}\right)\displaystyle\int\frac{KdN}{N\left(K-N\right)} = \int rdt \displaystyle K\int\frac{dN}{N}-K\int\frac{dN}{K-N}=r\int dt Now, I obtain: K\ln\left(\frac{N}{K-N}\right) = rt+c \left(\frac{N}{K-N}\right)^K=C_0r^{rt} The final solution is...
  4. N

    [topology] new kind of separation axiom? where does it fit in?

    Hello, Just out of curiosity, where would following "seperation axiom" fit in? So far I'm only acquainted with the T1, T2, T3 and T4 axioms (and the notion of completely regular in relation to the Urysohn theorem).
  5. I

    Amplitude and inter atomic separation

    Homework Statement The question goes something like this: What % of inter atomic separation is the root mean amplitude. The data given is: Inter atomic separation : 0.29nm , T =300k , D = 20 N/m , Aluminium atomic weight 27 g/mole. How do I proceed I have no idea on how to relate mean...
  6. L

    Linear Programming - Separation of points

    This semester while taking Linear Programming (Linear Optimization Models), we talked about using a linear program to separate two sets of points A and B. The general program is: Max d s.t. yA ≥ axA+b+d yB ≤ axB+b-d It can be expanded into finding a polynomial that passes between the...
  7. L

    Linear Programming - Separation of Points

    Homework Statement I made this problem up as an example for a bigger problem I have to do. P = {(-2,4),(1,3)} and Q = {(-1,1),(0,0)}. I need to use linear programming to find the best line to go between them. Homework Equations Max d subject to: y_{i}≥ax_{i}+b+d (for all points above...
  8. W

    How does induced charge separation work and why can it be confusing?

    Homework Statement I am having trouble understanding the concept of induced charge separation. In my textbook, there is a diagram that demonstrates the procedure, but it gets confusing because the first image is normal, and then it gets inverted? I don't understand in the second set-up if it...
  9. F

    News Constitutionality and the separation of church and state

    I was just wondering if there are any written documents which give the views of the United States founding fathers' views towards separation of church and state. The constitution reads, "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof"...
  10. G

    Minimum separation between pucks

    Two frictionless pucks are placed on a level surface at an initial distance of 20.0 m. The mass of puck 1 is 0.80 kg and it has a charge of +3.0 X 10^-4 C., while puck 2 is 0.40 kg with a charge of +3.0 X 10^-4 C. the initial velocity of puck 1 is 12.0 m/s (E) and the initial velocity of puck 2...
  11. G

    Angular Separation of Stars: Min Resolved w/ Diffraction Effects

    Homework Statement What is the minimum angular separation an eye could resolve when viewing two stars, considering only diffraction effects? Homework Equations θ=(1.22*λ)/D The Attempt at a Solution I tried estimating with λ=550 nm and D=5.0 mm (pupil diameter) which appeared in...
  12. B

    Flow separation in diffuser section of wind tunnel

    For my research purpose, I made a wind tunnel which has 0.6m rectangular section [0.2X0.2sq. meter] and 1.4m long diffuser section having porous top [top wall angle is 20deg] as follows: Wind tunnel speed is 15m/s. Even using 20deg inclination of porous top wall, there is no flow...
  13. G

    Minimum angular separation for viewing stars

    Homework Statement What is the minimum angular separation an eye could resolve when viewing two stars, considering only diffraction effects? Homework Equations Rayleigh criterion: θ=(1.22*λ)/D The Attempt at a Solution This problem doesn't give very much to go on so I think...
  14. J

    Nickel - Meteorite Separation

    Hi everyone! I'm looking to separate nickel from a meteorite sample and I have a pretty solid plan... however I'd like to know if there are any disadvantages of using the following methods: Quinoxoline Complexation with Spectrophotometric Determination (using pre-separation to remove...
  15. J

    PDE separation of variable problem

    Homework Statement Using the method of separation of variables, obtain a solution of the following PDE subject to the given conditions \frac{du}{dx}+y\frac{du}{dy}=(2x+y)u u(x,1)=5e^{x^{2}-x} Homework Equations The Attempt at a Solution See my attached working the...
  16. jinksys

    QM- Why is the separation constant +/-l(l+1) ?

    This isn't a HW problem, it's more of a general question. I'm reading Griffith's Intro to QM 3rd Edition. On page 134 he uses separation of variables, of which I'm familiar (but by no means an expert). Could someone explain why the separation constant in equations 4.16 and 4.17 changes sign...
  17. T

    Is there a lower limit to the separation between capacitor plates?

    Let's say I build a parallel plate capacitor using two metal plates with perfectly smooth surfaces. They are separated by some small distance d, with only vacuum between them. I then apply some AC voltage across the plates. Is there some effect which causes loss in the capacitor (equivalent...
  18. M

    Separation of Variables for a Rocket Launched in a Gravitational Field

    Homework Statement Taking the equation of motion for a rocket launched from rest in a gravitational field g, m\dot{v} = -\dot{m}v_{ex} - mg , and knowing that the rocket ejects mass (fuel) at a constant rate \dot{m} = -k (where k is a positive constant), so that m = m_{o} - kt . Solve...
  19. mishima

    Rate of change of separation distance

    Homework Statement This is from Calculus for the Practical Man, by J.E. Thompson, 1962 edition. "Two automobiles are moving along straight level roads which cross at an angle of 60 degrees, one approaching the crossing at 25 mph, and the other leaving at 30 mph on the same side. How fast...
  20. D

    Separation of variables for non-central potentials

    Dear Everyone, I have a question about the separation of variables for non-central potentials (r, \theta, \phi). In spherical coordinates, such a potential V(r,\theta)=u(r)+f(\theta)/r^2 can be separated. Who knows it could also be separated in other coordinates? Many thanks.
  21. D

    Does spacelike separation have anything to do with non-locality?

    The cause-effect relationship of timelike events is fairly self-evident. But I was wondering, do non-local effects of QM "synchronise" events that are separated along spacelike intervals? Could there be some kind of co-dependent arising, such that if event X happens in one region of the...
  22. N

    Solving Poissons Eqn w/ Delta Fn in RHS using Separation of Vars

    Hi Everyone, I am trying to solve the partial differential equation given below: \Delta^2\phi(x,y,z)=\frac{qf(x,y,z)}{\epsilon} where f(x,y,z)=1 at one point and zero elsewhere. This is the poisons equation for a point charge inside a conducting box. Can this be solved using the...
  23. J

    Separation of variables question

    Homework Statement Solve the following separable equation \frac{dy}{dx} = \frac{y}{x(x-1)} Homework Equations \int\frac{1}{x}dx=ln(x) The Attempt at a Solution See attachment Im getting y=(\frac{x-1}{x})^{c} as my answer when in fact the answer the tutor gave is...
  24. C

    Diffraction grating angular separation

    Homework Statement Light consisting of two nearly equal wavelengths L and L+dL, where dL << L, is incident on a diffraction grating. The slit separation of the grating is D. Show that the angular separation of these two wavelengths in the m'th order is dTheta = dL / ((D/m)2+L2)0.5...
  25. A

    Jordan-Brouwer Separation Theorem and Invariance of Domain

    So I'm having trouble understanding how these two are related, i.e., how one proves the other. I understand the ideas behind both of them: For J-B, you're basically taking R^n and throwing in a sphere, so the inside of the sphere is bounded and everything outside the sphere is unbounded. For...
  26. B

    Effect of suction flow rate over flow separation

    Dear all, Take my best wishes. I am facing a problem designing my experimental setup for my research. I want to produce flow separation over a flat plate. Here is my experimental setup: Diffuser angle is 16deg. I need some documentation/text book regarding the effect of suction flow rate...
  27. B

    Rotational and vibrating energy levels - find energy separation

    Homework Statement The equilibrium separation of the atoms in H35CI equals 1.27 x 10-10m. Calculate the energy separation between adjacent lines in the rotational-vibrational spectrum Homework Equations E = (n + 1/2)h\omega + h2/ 2I * l(l+1) I = \mur02 \mu = m1m2/ m1 + m2 The...
  28. B

    Unravelling the Separation of 35CI19F Atoms: A Problem Solved

    Problem: The adjacent lines in the pure rotational spectrum of 35CI19F are separated by a frequency of 1.12 x 1010 Hz. What is the equilibrium separation of the atoms in this molecule? The attempt at a solution So, the equation I think I need to use to find the equilibrium separation...
  29. J

    Proof of Jordan-Brouwer Separation Theorem Using Homotopy Theory?

    The other day I found an article which proved the Jordan Curve Theorem using the van Kampen Theorem for the fundamental groupoid of a space. I was wondering if this technique could be extended to prove the more general Jordan-Brouwer Separation Theorem, using higher homotopy groupoids, the "van...
  30. F

    Minimum Separation of Two Frictionless Pucks

    two frictionless pucks are placed on a level surface, as shown, at an initial distance of 20.0 m. the mass of puck 1 is 0.80 kg and it has a charge of +3.0 X 10^-4 C., while puck 2 is 0.40 kg with a charge of +3.0 X 10^-4 C. the initial velocity of puck 1 is 12.0 m/s (E) and the initial velocity...
  31. S

    Homogenous PDE with separation of variables

    Homework Statement Sorry don't know how to use the partial symbol, bear with me partial u wrt t=2*(2nd partial u wrt x) Boundary conditions: partial u wrt x (0,t)=partial u wrt x (1,t)=0 Initial conditions u(x,0)=x(1-x) Homework Equations I get an answer that is different...
  32. P

    Steam vs Fuly saturated air: Separation

    For water separation purposes, what's the difference between steam and fully saturated air? I was looking at a certain product: http://www.nciweb.net/combinat.htm And I'm not sure if such a thing would be suitable for separating the water from a fully saturated air stream at about 60degC...
  33. P

    Separation of water from air at high temperature

    How might one try to separate water from air at high temperature (say, 75degC) - if the gas if fully saturated? I understand that you should try to cool it down first to do so, but other than putting it though a heat exchanger is there any other approach you can take? Thanks
  34. V

    HELP Finding Initial Separation

    One particle has a mass of 3.00 10-3 kg and a charge of +7.50 µC. A second particle has a mass of 6.00 10-3 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.100 m, the speed of the 3.00...
  35. T

    Can I use Separation of Variables like this? (3 terms)

    \frac{\partial z}{\partial t}=\frac{\partial z}{\partial x}+\frac{\partial z}{\partial y} \mbox{Let }z=T(t)X(x)Y(y) T'(t)X(x)Y(y)=T(t)X'(x)Y(y)+T(t)X(x)Y'(y) \Rightarrow \frac{T'(t)}{T(t)}=\frac{X'(x)}{X(x)}+\frac{Y'(y)}{Y(y)} \Rightarrow \frac{T'(t)}{T(t)}=A \wedge...
  36. S

    Separation distance between wires - Magnetic fields

    Homework Statement http://i.imgur.com/mgIkS.png Two long parallel wires carry currents of 2.03 A and 8.83 A. The magnitude of the force per unit length acting on each wire is 4.49*10^5 N/m. Find the separation distance of the wires expressed in millimeters. Homework Equations I'm not...
  37. C

    Do I Need to Divide the Constant and Term in Separation of Variables?

    Im doing separation of variables now and I am stuck...ive come up to this stage -5 ln 2-3i = t^2/2 + C my problem is do i need to divide the C and t^2/2 by -5? or don't divide the C? please help me.. thnks
  38. M

    Solving ODE via Separation Method: Need Assistance

    Can anyone help me solve this ODE: ..in other words, find a general solution? dy/dx = e^(x+y) I use a separation method, but i can't take the natural log of -e^(-y). So, help?
  39. V

    Double slits separation & electron field size

    Supposed you want to send an electron to a double slit. What must be the separation of the slits if they are say 1 meter away? What is the size of the initial electron field? When it travels to the slits, does the electron field expand in size? Why? I'm asking this because I'd like to know...
  40. S

    Possible webpage title: Finding Solutions to ODEs with Separation of Variables

    a) Derive a formula for solutions of the ode equation b) If (t0, x0) lies in the subset of the (t,x)-plane given by x>1 write down a formula for the unique solution of the equation below through this point. c)Give a formula for two solutions to equation below through the point (0,1) in the...
  41. S

    Vertical double slit experiment separation of bright spots in air and water

    Homework Statement A scientist decides to do the double-slit experiment in a ver- tical tube, with the slits at the top and a viewing screen at the bottom as shown. With red light from a HeNe laser (632 nm) a nice pattern forms on the viewing screen, with the bright spots 1.50 cm apart...
  42. J

    Separation of Variables for Solving PDEs

    See attached image for the question and my working. Hopefully you can read it OK, I had to resize it to fit to the allowed dimensions. I'm unsure how to proceed or if I have done something wrong previously - the initial and boundary conditions are tripping me up. The boundary conditions in red...
  43. A

    Solving PDEs: Separation of Vars., Method of Characteristics

    I've taken a first semester course on PDEs. Basically all we learned was separation of variables and method of characteristics. I understand that there are transforms out there, such as laplace and fourier. However, it looks like there aren't many analytical ways of solving PDEs. Mind you, I'm...
  44. A

    PDEs separation of variables

    Just quick question about sep of variables.. say have function U(x,y)=X(x)Y(y) when do separation of variables end up with some generic case that looks like: X''/X=Y'/Y=lamda my question is (and I think I know now the answer but would like confirmation), is what sign should the lamda...
  45. A

    Potential energy and separation graph

    http://img835.imageshack.us/i/anmol.png/ the graph is as per the link but my question is that at a particular point the potential energy becomes zero...is thre any significance for it?
  46. S

    Separation of Variables for a PDE

    Homework Statement Use separation of variables to find a general series solution of u_t + 4tu = u_{xx} for 0 < x < 1, t> 0 and u(0,t) = u(1,t)=0. Homework Equations The Attempt at a Solution Looking for a solution of the form u(x,t) = X(x)T(t) implies that \frac{T'}{kt} - \frac{X''}{X} = 0...
  47. R

    Separation of Variables: Solving M(dv/dt) = [k*(v^2)] - Mg

    Homework Statement Help solving this separation of variables. M(dv/dt) = [k*(v^2)] - Mg Homework Equations As above The Attempt at a Solution dv/(kv^2-Mg)= dt/M Intregrate both sides; (1/2kv) ln |kv^2-Mg|= t/m + c? Then what to do..? Something to do with with Ae^(-kt/M)..?
  48. R

    A free-falling sky-diver. Using ODE and Variable Separation

    Homework Statement A free-falling sky-diver of mass M jumps from an aeroplane and beforen he opens his parachute experiences air resistance which is proportional to the square of the magnitude of his velocity. a) Show that the equation of motion for the sky-diver can be written as dv/dt = -g...
  49. A

    Will separation of variables work in solving this PDE?

    Homework Statement As part of the solution to a HW problem of mine, I have to solve the PDE p_t = -vk^2 p - k \delta p_k, where p = p(k,t) and v,\delta are known constants. Homework Equations I tried to look for a solution of the form p(k,t) = K(k)T(t) and found one, but I'm not sure if I...
  50. V

    Forced Vibrating Membranes and Resonance - Separation of Variables

    Homework Statement In the midst of Forced Vibrating Membranes and Resonance Utt = c^2*delsquared(U) + Q(heat source) Arrive at eigenfunction series solution where the coefficients are given by d^2/dt^2 (A_n) + c^2*lambda_n*A_n = q_n Homework Equations according to the book, I am supposed to...
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