Poles Definition and 240 Threads

The Poles (Polish: Polacy, pronounced [pɔˈlat͡sɨ]; singular masculine: Polak, singular feminine: Polka), also referred to as the Polish people, are a West Slavic ethnic group and a nation that shares a common history, culture, the Polish language and is identified with the country of Poland in Central Europe.
The population of self-declared Poles in Poland is estimated at 37,394,000 out of an overall population of 38,538,000 (based on the 2011 census), of whom 36,522,000 declared Polish alone. A wide-ranging Polish diaspora (the Polonia) exists throughout Europe, the Americas, and in Australasia. Today, the largest urban concentrations of Poles are within the Warsaw and Silesian metropolitan areas.
Ethnic Poles are considered to be the descendants of the ancient West Slavic Lechites and other tribes that inhabited the Polish territories during the late antiquity period. Poland's recorded history dates back over a thousand years to c. 930–960 AD, when the Western Polans – an influential tribe in the Greater Poland region – united various Lechitic clans under what became the Piast dynasty, thus creating the first Polish state. The subsequent Christianization of Poland by the Catholic Church, in 966 CE, marked Poland's advent to the community of Western Christendom. However, throughout its existence, the Polish state followed a tolerant policy towards minorities resulting in numerous ethnic and religious identities of the Poles, such as Polish Jews.
Poles have made important contributions to the world in every major field of human endeavor, among them Copernicus, Marie Curie, Joseph Conrad, Fryderyk Chopin and Pope John Paul II. Notable Polish émigrés – many of them forced from their homeland by historic vicissitudes – have included physicist Joseph Rotblat, mathematician Stanisław Ulam, pianist Arthur Rubinstein, actresses Helena Modjeska and Pola Negri, military leaders Tadeusz Kościuszko and Casimir Pulaski, U.S. National Security Advisor Zbigniew Brzezinski, politician Rosa Luxemburg, painter Tamara de Lempicka, filmmakers Samuel Goldwyn and the Warner Brothers, cartoonist Max Fleischer, and cosmeticians Helena Rubinstein and Max Factor.

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  1. bnich

    I Getting zeros and poles for Laplace transform

    I'm following the intuition behind getting the zero's and poles of a damped cosine function with this video At around 11:50, he shows some graphics pertaining to multiplying the probing function with the impulse response, but the graphics don't seem correct. For example, in the B+B' graphic...
  2. R

    Induction motor windings, number of turns per phase and per pole

    Hi, I have some question regarding windings on induction motors, if anybody can help. Reviewing some literature (*), the usual formulae to get the number of turns per phase of a induction motor winding is Eph= RMS phase voltage [V] Nph= number of turns of phase winding f= frequency [Hz]...
  3. S

    A Atmospheric Density Required for Mercury´s Polar Regions to be Warm?

    Venus has a dense atmosphere (about 90 bar). Although Venus has a low axial inclination and the poles of Venus are therefore always in twilight, the day side atmosphere heats to about +460 C and the heat transport at the 90 bar atmosphere is so efficient that the poles are no more than 10 C...
  4. M

    Force between poles of two magnets

    The Biot-Savart law gives us the magnetic field created by an electric current. We can calculate the force exerted on a moving charge by this magnetic field using Lorentz's force formula. But my textbook doesn't address the repulsive or attractive force between like or unlike poles...
  5. vdance

    How are the poles of a tapered magnet distributed?

    How are the poles of a tapered magnet distributed? Is there any way to calculate its magnetic force?
  6. V

    B Magnetic generator multiple poles. Cancel out or short circuit?

    Science project. Real generator. But self made generator multiple magnets. What happens if I spin bar magnets inside a copper wire ring? Instead of rotating 2 separate copper rings inside a magnet that will split different flowing current on to different wires where a brush can join them...
  7. J

    B Radiation Levels at Earth's Poles

    Given that the magnetosphere plays a major role in protecting life here on Earth, how hazardous is the incoming space radiation at the poles? Here I mean at ground level, as opposed to being in an airplane. I'm thinking especially about solar flares, coronal mass ejections, and the like, but...
  8. P

    A Carnot engine between the Earth's poles and equator

    Earth absorbs and releases a massive amount of energy as a part of the day night cycles.(~100 Peta watts of solar radiation received) And the temperature difference between the poles and equator drive weather phenomenon, which happens at an energy scale beyond technology. I am wondering if one...
  9. Brian1776

    PID - Root Locus (Sisotool) for Transfer Function with Zeros and Poles

    Hi everyone! I have a 8th order transfer function, you can see it in the first image: % Transfer function num = [2.091,0,203.3,0,-2151,0,-1.072e05]; den = [1,0,-830.4,0,-1.036e05,0,-5.767e05,0,2.412e07]; tf = tf(num, den) I need to use a PID, so I'm trying to use a compensator, adding poles...
  10. V

    BLDC Motor - Finding out how many Pairs of Poles and the difference with PMSM

    Hello Community, i have BLDC motor with General parameters are 3 Phase motor with 4 Poles, 36V, 7.3A rated current, 4000RPM rated speed. you can check datasheet on link below The first question is how many Pair of Poles does this motor have? 2 or 4? For example the motor bellow...
  11. K

    Magnetism -- Clarification about North and South magnetic poles

    When I look at images of the pattern of iron filings around a magnet I cannot see any difference between the Pattern at the 'North' and 'South' poles. The present model also says that the field 'flows' from North to South but if this were the case it would not be necessary to move a magnet near...
  12. AN630078

    Gravitational Field Strength at the equator and poles

    1. The centripetal force is equal to F= mv^2/r. The velocity of the Earth can be found by: V=2πr/T T=1 day = 24 hr*60min*60sec=86400 s v=2π*6.4 x 10^6/86400 s v=465.4211 ... ~465 ms^-1 to 3.s.f Therefore, F=1*465/6.4 x 10^6 F=98/1280000=7.265626 *10^-5 ~7.3 *10^-5 N Would this be correct since...
  13. johnboyman

    Building a three phase motor -- figuring out how many poles

    Hello. I am building a three phase motor for a science project of mine. I am trying to match my motor with an inverter so i need to count how many poles I have in this motor. The problem is that I have read about this and some people say that this...
  14. tworitdash

    A Integrating a function of which poles appear on the branch cut

    I have a complicated function to integrate from -\infty to \infty . I = \int_{-\infty}^{\infty}\frac{(2k^2 - \Omega^2)(I_0^2(\Omega) + I_2(\Omega)^2) - \Omega^2 I_0(\Omega) I_2(\Omega)}{\sqrt{k^2 - \Omega^2}} \Omega d\Omega Where I0I0 and I2I2 are functions containing Hankel functions as...
  15. tworitdash

    A Spectral domain double integral with singularities

    The integral looks like Y_{mut, mn} = -j^{m+n}nm \int_{-\infty}^{\infty}\int_{-\infty}^{\infty} \frac{2 ab (k^2 - k_x^2) \sin^2(\frac{k_yb}{2}) \cos^2(\frac{k_xa}{2})}{\omega \mu k_z (\frac{k_yb}{2})^2 [(n\pi)^2 - (k_xa)^2][(m\pi)^2 - (k_xa)^2]} dk_x dk_y Here, k_z = -1j \sqrt{(-(k_0^2 -...
  16. J

    Conventional current, magnetic fields and magnetic poles of different diagrams

    I need to do question 1. I understand the right hand rules but am lost on what to do here.
  17. starstruck_

    Determine the singularity type of the given function (Theo. Phys)

    NOTE: Was not sure where to post this as it is a math question, but a part of my "Theoretical Physics" course. I have no idea where to start this and am probably doing this mathematically incorrect. given the function f(z) = cos(z+1/z) there should exist a singular point at z=0 as at z = 0...
  18. D

    I What is the Topological Interpretation of Orders of Poles in Rational Functions?

    Hi. If I look at the function ## (z^2+z-2)/(z-1)^2## it appears to have a double pole at z=1 but if I factorise the numerator I get ##z^2+z-2 = (z+2)(z-1)## and it is a simple pole. Is it wrong to say it is a double pole ? If I overestimate the order of the pole in this case as 2 and...
  19. L

    Poles of the self-energy in atoms and molecules

    We can use the method of the Green functions to calculate ioniation potentials and electron affinities of atoms and molecules. These quantities can be determined if we know the self-energy ##\Sigma(E)##, that is a function of the energy ##E##. A matrix element of the self-energy in the basis of...
  20. S

    I Poles in Casimir force as function of frequency & mode

    In Numerical methods for computing Casimir interactions, we have this expression for the Casimir force between two plates: where I am trying to interpret this physically on a per-frequency and per-mode basis, before actually looking at the complete integral. If we focus on a single...
  21. Baibhab Bose

    A Understanding the Order of Poles in Complex Functions

    When The denominator is checked, the poles seem to be at Sin(πz²)=0, Which means πz²=nπ ⇒z=√n for (n=0,±1,±2...) but in the solution of this problem, it says that, for n=0 it would be simple pole since in the Laurent expansion of (z∕Sin(πz²)) about z=0 contains the highest negative power to be...
  22. L

    Finding the torque on a wire between two poles

    Homework Statement [/B] A rectangular wire of length 3 cm and width 2 cm is suspended vertically between two poles producing a uniform field of 2 T. Calculate the maximum torque acting on the wire.Homework Equations Torque = AIB sin(Θ) Maximum torque is when sin(Θ) = 1, so Maximum Torque = AIB...
  23. sophiecentaur

    B North and South poles of Mars are at different temperatures?

    The images I have seen of Mars seem to show a more pronounced polar 'ice' cap on the South Pole than at the North. Could that be something to do with the times in the Martian year that the images are all taken (relative orbital positions vs winter and summer) or something else? Earth's South...
  24. A

    B Why are aurora always in the vicinity of Earth's poles?

    Why aurora happen near north or south pole more easily? I mean why charged particles can escape the Van Allen belts more easily to have collisions with particles in the atmosphere? Why are they harder to escape near equator? Isn't it supposed to have weaker magnetic field near the equator?
  25. J

    Residue at poles of complex function

    Homework Statement Homework Equations First find poles and then use residue theorem. The Attempt at a Solution Book answer is A. But there's no way I'm getting A. The 81 in numerator doesn't cancel off.
  26. kyphysics

    What's w/ the news of Earth's magnetics poles about to flip?

    Anyone else seen lots of recent news articles on this? Is it as scary as some portray?
  27. CAT 2

    Magnetic poles and field problems

    Homework Statement Draw this diagram: Now do the following: find the unknown poles labelled with a question mark draw the magnetic field around the conductor shown determine the direction of the force acting on the conductor Homework Equations Using the right-hand rule can help to solve...
  28. A

    I Optimizing Lunar Power: North vs. South Poles for Mining and Moonbase Sites

    North or South? Which is better for prospecting, mining, a site for a Moonbase and solar power. This could be quite a crucial question. The first solar array in permanent (ish) sunlight will stake a claim, because the next one will threaten to put it into shadow at certain times in the Lunar day.
  29. binbagsss

    Product of modular forms: poles, zeros expansion

    Homework Statement question concerning part c. Homework Equations The question is pretty simple if there is no zero of order ##N## at infinity, such that it does not cancel the pole of ##f(t)## at infinity of order ##N##. In this case it follows that ## f(t) g(t) \in M^{!}_2 ## and so we...
  30. W

    Determining the Poles of a Magnet Using a Hall Probe and Lab Equipment

    Homework Statement Determine the direction of the dipole moment of a magnet with unknown poles. You are given a Hall probe and can use other devices commonly found in a lab. Homework EquationsThe Attempt at a Solution I was thinking since the Hall probe uses voltage to determine the strength...
  31. J

    Exponential forcing function to an RL circuit -- poles & zeros

    For reference: Engineering Circuit Analysis, Hayt & Kemmerly, 4th ed, 1986, page 345. Given a series RL circuit, the phasor current is I(s) = Vm/(R+sigma L), where S = sigma, w (omega) = 0. Thus we are dealing with only a exponential forcing function. Obviously I(s) goes to zero as sigma...
  32. S

    Chemistry Determining the positive and negative poles of a molecule

    Homework Statement For the molecule CHCl3, a) Draw the electron dot diagram and structural formula b) predict the shape c) predict whether it is polar or non-polar, and justify your prediction. Indicate the positive and negative poles. Homework Equations none The Attempt at a Solution [/B]...
  33. Noisy Rhysling

    Specifications for elephant-resistant steel poles

    Reposted to help a guy out... Specifications for elephant-resistant steel poles http://www.skepticforum.com/viewtopic.php?p=584279#p584279by Williamhdc » Tue Jun 20, 2017 5:17 am This is probably simple for an engineer, but I’m a zoologist and analytical chemist and so I would rather ask those...
  34. Chatterton

    Figuring out which stars an exoplanet's poles point to

    I know Earth's north pole points to Polaris and during the 26,000-year precession cycle, it will also point to Demeb, Vega, and Alpha Draconis. But... Is there a reference that'll help me figure out what Proxima Centauri b's most likely pole star candidates would be? I know, so many variables...
  35. J

    2D Integrating With Quadratic Arg. of Delta Function

    Homework Statement I have a 2D integral that contains a delta function: ##\int_{-\infty}^{\infty}\int_{-\infty}^{\infty}\exp{-((x_2-x_1)^2)+(a x_2^2+b x_1^2-c x_2+d x_1+e))}\delta(p x_1^2-q x_2^2) dx_1 dx_2##, where ##x_1## and ##x_2## are variables, and a,b,c,d,e,p and q are some real...
  36. J

    A Analytical Integration of a Difficult Function

    Is it possible to integrate the following function analytically? ##\int_{0}^{\infty} \frac{\exp{-(\frac{A}{\tau}+B\tau+\frac{A}{\beta-\tau})}}{\sqrt{\tau(\beta-\tau)}}d\tau,## where ##A##, ##B## and ##\beta## are real numbers. What sort of coordinate transformation makes the integral bounded...
  37. J

    A Is the pole in this integrand integrable?

    I am trying to numerically integrate the following complicated expression: $$\frac{-2\exp{\frac{-4m(u^2+v^2+vw+w^2+u(v+w))}{\hbar^2\beta}-\frac{\hbar\beta(16\epsilon^2-8m\epsilon(-uv+uw+vw+w^2-4(u+w)\xi...
  38. binbagsss

    Elliptic functions, residue computation, same zeros and poles

    Homework Statement Hi, I am trying to understand the attached: I know that if two functions have zeros and poles at the same point and of the same order then they differ only by a multiplicative constant, so that is fine, as both have a double zero at ##z=w_j/2## and a double pole at...
  39. P

    Specifications for elephant-resistant steel poles

    This is probably simple for an engineer, but I’m a zoologist and analytical chemist and so I would rather ask those who know. I have camera traps out on the African bush, that are monitoring the responses of leopards to artificial scents. The cameras are in steel boxes to protect them from...
  40. C

    Control Systems - How to find dominant poles *without* MATLAB?

    Homework Statement Design a lag-lead compensator for the system of Figure 9.37 so that the system will operate with 20% overshoot and a twofold reduction in settling time. Further, the compensated system will exhibit a tenfold improvement in steady-state error for a ramp input. Homework...
  41. F

    I Deformation of contour of integration or shifting poles

    As I understand it, in order to compute a contour integral one can deform the contour of integration, such that it doesn't pass through any poles of the integrand, and the result is identical to that found using the original contour of integration considered. However, I have seen applications...
  42. binbagsss

    Elliptic functions proof - finitely many zeros and poles

    Homework Statement Hi I have questions on the attached lemma and proof. ##f(z)## is an elliptic function here, and non-consant ##\Omega## is a period lattice. So the idea behind the proof is this is a contradiction because the function was assumed to be non-constant but by the theorem that...
  43. J

    I Inhibit repulsion between two like poles

    Please excuse the lay terms that will follow. I have been doing some reading on "magnetic shielding" and have come across alloys such as MuMetal which have high permeability and so can block interaction between two magnets. My question; Is this inhibition of interaction between the two...
  44. G

    Rigorous definition of magnetic poles?

    Hi. Since there haven't been observed magnetic monopoles so far, what exactly do we mean when we talk about the north/south pole of a magnet? Is it something like "north is where the field lines exit a solid body" and "south is where they enter" or is there a more rigorous definition?
  45. DaveC426913

    Graphic: a global grid but not emanating from poles

    This is for a fictional project, but the tools I need will more likely be found here in Earth forum, I think. Move to fiction if necessary. I want to render a map of Earth with the "poles" of the grid in a different place. Say, the South "pole" of the grid is at Tierra del Fuego (ish) in S...
  46. M

    Plotting magnetic field lines between two adjacent NS poles

    This question is regarding the magnetic field lines around two abutting alternating poles. Take two axially magnetised disc magnets and place them next to each other (like tangent circles), so on each side the adjacent or neighboring magnet is of the opposite pole. By sprinkling iron filings...
  47. R

    Calculating Poles in a 3-Phase Induction Motor

    how many poles does 3 phase, 60 hertz induction motor which runs at 715 r/min at no load and at 670 r/min at full load have and how is it calculated?
  48. Liam A

    I Understanding the Polar and Equatorial Temperature Differences on Planets

    on earth, we have the poles being very cold and mostly frozen, while the equator is very warm and humid. i would like to know specifically what causes this. i know it is partially because of their exposure to the sun, but i'd like to know some of the details and factors involved. i'd also like...
  49. R

    2nd order RC filter with two equal poles

    Is it possible to make a 2nd order CR LPF or HPF where the cut off frequencies for each pole are equal? Here is a calculator for this system which includes the transfer function.http://sim.okawa-denshi.jp/en/CRCRkeisan.htm I figured that I need to try to solve the denominator of the transfer...
  50. DarkMatter5

    Coriolis Force Across the Equator

    Homework Statement A fast sprinter with a mass of 80 kg runs across the equator. What is the value of the Coriolis force he experiences? Homework Equations F=ma a=2ωVradial ω=7.27 x10-5 rads-1 Earth rotates from west to east. The Attempt at a Solution I pick a direction of travel - South to...
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