Core Definition and 469 Threads

Hello everyone. I am glad I came across this science oriented Forum site. I actually get there from Google and what I am deeply curious to know about is the amount of Maximum Voltage my 3.5kg Air Core Electromagnet can bear. The Core of the Solenoid is 120mm in height and 13inches in...

Dear PF Forum, Does the Earth core produces its own energy? If it is true, how? Radioactive decay? Gravity? Earth core temperature is around 4000 Celcius. Almost like the sun surface temperature. How can that temperature kept for 4 billions of year? Can the temperature heat the mantle and Earth...

Hi, I'm just curious why we model the ideal inductor as having the leakage inductance as being in series with the ideal core, rather than in parallel to it? Because it would seem to me that the flux goes in two parallel directions, one through the core, and one through the air around the core...

Core being Thermal, Mechanics, E&M, Quantum? Say I graduate with a average 3.4 gap, but ace these courses, would Grad admissions care about a rough first year including Cs in Calc I and II and Bs in General Physics?

Hi everybody i want to simulate, low frequency ferrite core receiving antenna . but i can't find a good and complete software or method to do this. what is your suggestion or experience? thanks for your attention.

Suppose you have a pure DC supply with a constant current to an inductor. And you change the core of the inductor from air to iron, leaving the current remain the same. You may try changing to other materials. Does the voltage drop across the inductor will remain the same for any core? Anyone...

Where are the world's Established core routers situated? On which major protocols do they run?

I have a question that I can't figure out , there is a toroidal transformer , and the core has an attached part on which another coil is wound. the main coil of the toroidal transformer is connected to a DC source. which creates a static magnetic field in the torus core. the other coil at the...

Over the years I've learned a lot about TXs etc. But I'm a bit rusty. Any thoughts on general reminders about core saturation. I know there are huge issues, but the specifics I can't remember that well. I vaguely remember hearing something like when there is a DC component on a transformer the...

1) Is there any evidence that the Earth's magnetic field originates in the core rather than elsewhere? 2) Is there a compelling physical model?

Hello everyone, I read somewhere that it is preferable to use insulated iron wires instead of a single iron core inside an electromagnet. Anybody has an idea on why is that and what difference does it make to use each? Thanks in advance.

47 x 62 = ? (40+7) x (60 + 2) 40 x 60 + 40 x 2 + 7 x 60 + 7 x 2 2400 + 80 + 420 + 14 2480 + 434 2914 Consider a rectangle with dimensions 47 units by 62 units. The rectangle can be subdivided into four smaller rectangles: 40 x 60, 40 x 2, 7 x 60, 7 x 2. So when kids multiply two...

I'm using a U-Shaped Ferrite Core with coils in both legs of the U. I've calculated it's inductance using an analogy between electric/magnetic circuits. L = N2/Rtotal where: N = number of turns of coil in both legs of the U; Rtotal is the total reluctance of my circuit = R1 + R2 R1 =...

Hello everyone, I'm not sure if the title makes sense, but I'll try to explain it a bit better here. So, if we have a transformer with an open iron core (U shaped iron core, with coils wrapped around each side, same number of coils, same thickness), why is the electromagnetically induced emf in...

Hi, I am planning to conduct an experiment using electromagnet but I could not find the soft iron core. My school lab doesn't have it, and I tried asking around in shops which sell electrical appliances and shops which sell science apparatus but nobody seems to sell it. Does anyone know where...

Homework Statement Jupiter has a core of liquid metallic hydrogen, with uniform density $\rho_c$, with radius $R_c$. This is surrounded by a gaseous cloud $R_g$, where $R_g>R_c$. Assume the cloud is of uniform density $\rho_g$. The problem also specifies that we are to assume both regions of...

What would happen if the core of the Earth suddenly disappeared? Would the gravitational field it emitted immediately disappear because the mass at the center disappeared. Would the surrounding Earth collapse into where the core used to be because of it being pulled there or would a new center...

Hi, I'm trying to make a simple model of stellar evolution for a game project of mine, but I'm not sure how to predict the radius of a star's core without reference to its surface radius. I am trying to derive the surface radius from the amount of energy being released by the core. The goal is...

Hi everyone, I have to build a simple Joule thief circuit for school. Here it is :(http://upload.wikimedia.org/wikipedia/commons/8/83/Joule_thief.png). The resistance of the resistor is fixed to 1 kOhms, the voltage across the "dead battery" is about 1.5V, the transistor needs about 0.7V to...

I am currently working on thermal-hydraulics of a small PWR. The configurations are: Thermal power (MWth) 333 Core height is 1.8 m Pressure (MPa) 15.5 Total rod diameter (mm) 9.50 pin pitch (mm) 12.65 Pitch/diameter ratio 1.33 Flow Area (m2) 8.92E-05 Intlet mass flow/area (kg/m2/s)...

Thanks to a novel application of earthquake-reading technology, researchers have found that the Earth's inner core has an inner core of its own, which has surprising properties that could reveal information about our planet. http://www.sciencedaily.com/releases/2015/02/150209113222.htm The...

Hello Engineers, while simulating transformer core losses in transient Maxwell sollution, I have got an error: Current leak to the air. does anyone ahev idea to solve this problem Thank you

Let H be a subgroup of G, then: Core H = {a in G | a is an element of gHg^(-1) for all g in G} = The intersection of all conjugates of H in G My book goes on to say that every element of Core H is in H itself because H is a conjugate to itself. Previously, I understood that H was a conjugate to...

Milky Way core drives wind at 2 million miles per hour -- ScienceDaily http://www.sciencedaily.com/releases/2015/01/150105182525.htmThe article graphic shows three distinct flows of material... One moving towards earth One moving away from earth And One with no net motion along the line of...

Hi , When DC is applied to a transformer there is no secondary induction because DC current creates no changing flux in the Core. If I could change the reluctance, or permeability is another word I guess, of the transformer core while still having DC applied to the...

An air core circular coil of n turns produced a magnetic field of (for eg) 0.5 tesla at a point in space (not within the coil nor along the axis of coil). If a ferrite core of μr (relative permeability)=200 and of the same length of the coil is inserted into the coil what happens to the magnetic...

Hi, I was wondering if anyone knew if you could use a magnetic amplifier: http://en.wikipedia.org/wiki/File:Magnetic_amplifier.svg as like a variable resistor for controlling current from the source to the load? I imagine there would be a large voltage imposed across it when it is a high...

hello! is it possible to heat the core of an object or a specific point inside the object? or are there specific objects we can do that? obviously after heating a specific point inside the object, the rest of the object will conductively heat up too, but I wonder if there is a way to...

For dealing with different types of loss of coolant accident (LOCA), pressurized water reactors (PWR) have emergency core cooling system (ECCS). ECCS are simply redundant pumps to inject water into core to cool fuel, thus preventing fuel melting in case of an accident (hypothetical) that involve...

Homework Statement Explain why stage 1 and 2 of the triple alpha process will not being until the core Temp of the star is around 10^8K. Homework Equations 4He+4He = 8Be (step 1) 8Be+4He = 12C (Step 2) The Attempt at a Solution I "think" I need to work out the nuclear energies... However I...

I'm curious about something I read comparing the power released in the core of the Sun being comparable to a compost pile (~276 W/m^3). This seems very low (Wikipedia confirms this value). The value I find for power in the core is on the order of 10^26 W, and using the volume of the core of...

How would you approximately describe matter in the core of underlying neutron star? I am asking for really fundamental properties. No strange matter, consider just n,e,p. A ratio, can we describe particles as free? Gas x fluid x superfluid? etc.

Given the increase in geophysical phenomena (such as earthquakes and volcanic eruptions), it is obvious "something" IS going on with our planet. I have no trouble believing in this theory that a reversal of the Earth's magnetic field may be included -- sooner as opposed to later. However, no...

Hi All, I'm trying to create something which has a solid, cylindrical, non-reflective core (assume the core is made out of a black rubber similar to that of a car tyre for instance and 20m in length, but only 1cm in diameter), which has a translucent or transparent plastic layer (or several...

A normal star's core consists of Hydrogen but a white dwarf is itself the core and it consists of stellar ash. So the degeneracy pressure is exerted when this stellar ash becomes very dense (In other words when the white dwarf becomes very dense). Am I right? The density of a white dwarf is so...

How long before our magnetic field disappeared and how long after that would we be dead due to radiation?

hello. I'm designing a 100w 4Mhz class E amplifier. I need a ferrite core transformer for impedance transformation and load isolation but unfortunately I lack the knowledge required for designing it. if anyone could guide me to a good book or a web page, or simply give me some formulas I would...

It was estimated that the heat inside the core of the Sun inside around 15 000 000 °C - this value is extremely enormous. How did scientists estimate this value?

So at some point nuclear fusion in a star becomes unable to sustain the core against its own gravity pressure, then the core collapses and the surface explodes in supernova explosion. What actually happens when the core collapse that makes the surface explode, and why would the core not explode...

I'm attempting to build an alternating current electromagnetic coil and want to maximize its potential field. My initial query was to find the very best core material for the electromagnet. I found an older post (2005) on the subject and saw some very interesting answers there. Being new here...

Is it true that a pinhead size if the Sun's core if materialised on the Earth would be too dangerous to go within 90 miles of it? I read from Wikipedia that the energy produced in the Sun's core is about 270 watts/m3. About the same as an active compost heap. I know the pinhead of core matter...

So I want to fire a magnetic ball through a solenoid coil but want to know if core material can enhance the performance. Would wire wrapped around soft Iron tube core work better then say a thin copper tube? The aim is to increase efficiency so less power needs to be used to fire the magnetic...

A laminated iron core was inserted into a coil with an AC current flowing in the coil. 1.The current in the circuit decreased after inserting the core. 2.Also the magnetic field was found to be stronger on the outer edge than in the center of the laminated iron core. How to explain the fall...

water as coil "core" How much a coil inductance of 0.1 mH (3 cm long, some 50 turns wound around 5 cm diameter empty plastic pipe) may change when water enters the pipe ?

I bought a Stainless Steel soap bar and it works, it just does. It was from China and hollow inside and I would like to know if that's either a cost cutting measure or how the bar works? What would happen if it were solid? Another thing would be if it had a magnetic core, or made from a metal...

Homework Statement A coil is connected in series with a bulb and this combination is connected to a DC source. When an iron core is inserted in the coil, what will happen to the brightness of the bulb? The Attempt at a Solution When the iron core is inserted, the magnetic field...

Hi, I'm currently writing a lab report on single phase transformers and I need to determine the equivalent circuit with respect to the secondary side. I have already found the parameters with respect to the primary side so it is just a matter of referring them to the secondary side. What I would...

Homework Statement Imagine standing on a scale and riding in an elevator at constant speed in a radial direction from the center of the Earth to a distance 3RE above the surface- I'm supposed to plot weight vs time so what I'm looking for an equation(s) I can use to find weight. *Assuming...

If I was going to build a fusion device for energy production I would build a cylinder filled with fusion fuel and the fusion would happened in the center. First it would be hard to start the fusion with relatively cold fuel. After a while of heating, the surrounding fuel would be hotter even if...

Falling matter of supernova does "work" heating the core? A supernova core collapses and the rest of the star follows, inner layers arrive first, a shock wave wave forms? As outer layers continue to collapse and slow down is there a large radial time rate change in momentum as rapidly...