Grid Definition and 222 Threads

Circuler grid need to be solved by Finite difference method! pls help me... hi this is the picture of the problem.. i have studied the rectangular grid but not the circular grid... now pls someone help me to find out the way to solve a heat conduction problem for circle using finite difference...

[b]1. I have not seen IEEE 1547-2003 as this question pertains to it. They say that small PV systems are tied into the grid, if the wave sign of a PV inverter is a square wave how does that marry to the wave of electricity flowing on the existing grid? Does this current just get gobbled up so to...

Hi, this might be a stupid question, but I was wondering how to computer the gradient of a quantity on a grid. I mean I have a grid made of cells (not necessarily of the same size) where the variable \rho is defined at the center of every cell. How can I compute the gradient of this quantity? It...

First, my apologies ... my last math class back in high school, sophomore year geometry, many years ago. I am a graphic designer, but have discovered an interesting math problem and would like some help identifying what it is and how to better express and use it. Thanks for any help! And...

In North America, awareness of smart grid/smart meters remains low. Mainstream media doesn't discuss much about this technology. People who protest against it get arrested. So, I got curious. Could you describe your biggest concern relative to smart grid/smart meters? I was told to search...

Hi, I need help with simply starting to prove this. I'm terrible with proofs and even the easy ones are hard for me. Any tips to get started in the right direction would be appreciated. A city represented by an infinite square grid of blocks is on fire. Every day, the status of city block is...

Hey all - this is my first post on the forum but I've browsed for help for a really long time on other topics. Any help would be greatly appreciated! So I have a function, called stability.m that takes in two independent variables, say x and y, as input and outputs either a 1 or a 0 for each...

Greetings, How far apart should the wires be on a 2.4 GHz parabolic grid antenna? Is it determined by the frequency? Thanks

Hi all, i would like to know if there is anything working on power grid simulation or other related work. I'm currently working on power grid simulation and would like to talk to people with experience in it. Any idea how to simulate the power grid with distribution generations like solar...

I'm reading The Lightness of Being by Frank Wilczek and I'm trying to work out what credence I should give the idea of "The Grid". Several questions. Isn't his "Grid" just the same as the old fashioned idea of ether? If not, how does it differ from "ether"? How does this idea stand...

Wanted: video by Wilczek on "The Grid" Does anyone know of a video lecture on the WWW by Prof Wilczek describing his theory of the Grid? (Suitable for someone with a basic science knowledge.) Thanks.

Homework Statement What is the resistance between A i B if resistance is proportional to length, and the resistance of a side of the largest square is R? Homework Equations This is nothing more than a bunch of serial (parallel) resistors. The Attempt at a Solution n=1 => R=1 n=2...

Hi, Not sure if this is the correct sub-forum or not. Perhaps, general math is better. Anyways.. In the following, a simple reference covering what I am after would be very helpful. Let's say you have a 4x4 grid of cells each cell contains either a 1 or 0. Let's say it is this...

You can chart the square roots relative to each other starting with a quarter-circle, a square, and a diagonal line. Where the circle intersects with the diagonal, the next square root is found. http://www.perspectiveinfinity.com/images/rgsteps_w.png More here...

1) What's the voltage in the overhead power lines in residential areas? Basically how many volts is it before it gets stepped down to 120 for your house? 2) What's the typical primary inductance of a distribution transformer that does the stepping down?

Hi, I'm a newbie here, i joined just now purely to ask this question that's been on my mind recently. Now i apologise if this question is fundamentally wrong (which it probably is), but I'm only the average person with an amateur interest in physics :P So don't laugh. Firstly, as you know, we...

can anyone tell me if it is possible to run a asynchronous generator from a capacitor bank and what it may entail.

What would happen if I hooked up a generator at my house (voltage and frequency identical) to the power grid and it was 180 degrees out of phase?

Hey all, Well for my senior project my class has to construct a mini grid. It will be connected to 3 renewable energy sources. My team is in charge of the connections to the grid and the energy sources. My team has decided to use a PIC micro controller to interface to the other groups. I am...

Hello. I want to build an electron accelerator grid in vacuum. The grid, which has the purpose of accelerating or decelerating electrons produced by a nearby filament has to be electrically charged at +500V or -500V. The switching frequency between the voltages +500V to -500V has to be...

All about smart grid, New ideas and news about what's happening now in this area. Including Smart meters, Renewable Energy (Solar and Wind), Green Cars and Green IT. Lets start from the beginning What is the definition of Smart Grid?

How many possible games of "go" are there? I realize this is a ridiculous question, but what strategies would you take to solve it? A sure-fire but incredibly tedious one would be to create a giant tree diagram. And before anyone says it, the answer is not just the factorial of (19*19)...

Hi, I have a problem (1) where I need to compute the ratio of probabilities of hitting and stopping at a positive vertical barrier x vs hitting and stopping at a negative horizontal barrier y after starting from (0,0). I feel that by symmetry, the answer to this would be the same as...

I want a projection of Earth where distances are undistorted. i.e. 10 degrees of latitude at the equator is exactly the same map distance as 10 degrees of latitude at the Arctic Circle. As a disqualified example, the Mercator Projection has map distance increasing with increasing latitude...

Hi, I'm here for help and hope somebody could give a hand on this because I'm noob in this. I'm now constructing a MATLAB program to find Electrical field and potential within a square grid mesh with square cavity inside. like the picture above. I only manage up to this...

I am trying to find out how many possible puzzles can be created out of the standard 9x9 grid. I was never very good at permutations and combinations, so I won't get very far here... All I can think of at the moment is that while there are 9^{81} ways to fill all the boxes with numbers from...

Guys, I have a Lister generator that is capable of producing approx 5KW of power from an attached ST alternator. I am in australia so our standard power is 240v at 50hz I have a grid tie inverter for my solar panels - this unit accepts between 150v dc into 500vdc It has a single input...

I know, I know. I didn't fill out the thing. But I don't really have a 'problem' to solve, I'm just looking for some vague theoretical speculation... I'm a new media art student and I'd like to use a grid of electromagnets to undulate a layer of low-lying fog (which would be glycerin +...

I'm doing some classic research into the possibility of replacing copper core power transmission lines in the United States power grid with tubes designed to contain low temperature plasma. The idea is that one would be able to transmit power more efficiently and effectively in plasma opposed...

Through our research we discover that an AC induction motor can act as a DC amplifier, as long as there is torque making it turns. Applying the process we are able to build RPM independent grid tie induction generator. Tested with variable US grid at consumer configuration. Similar to PMA...

"Evolving grid" simulation? I'm not quite sure what to call this problem, but basically, I am trying to solve a puzzle. It works as follows: There is a 9x9 grid Each square can either be "on" or "off" At the beginning of the puzzle, the 9 squares dead center of the grid are "on", the...

Place the letters A, B, C, D, E, F, G, H and I into a 3x3 square grid with each square containing a different letter, using the following information: (i) I is in the same column as E which is not in the center column. (ii) D is in the row below the row which contains F. (iii) A is in...

I'm working in matlab, and looking for help on how to do the following. (answers in any language or pseudocode will be fine) I have an nxn matrix, with each cell containing a 1 or a 0. The border cells are all 1's. Is there an efficient algorithm to determine if there are any "islands" of 1's...

Hello everyone: I am a C++ newbie; I am interesting in using C++ in my work on coupled fluid flow-chemical reaction problems. I apologize in advance for what is probably a very simple question. I would very much appreciate any help to get me on the right track! My goal is to come up with...

The Grid, dark energy not created at BB ? In his book “The lightness of being” page 105, Frank Wilczek says: “The concept of Grid density is essentially the same as Einstein’s cosmological term, which is essentially the same as “dark energy” “. Dark energy, contrary to the other energy...

I always have difficulty with logic puzzles. Usually, I miss making inferences that really make the puzzle's solution flow out. Are there any good books/resources that train people on logic puzzles? (I moved this from the brain teaser forum) The kind of puzzle I'm talking about would go...

http://www.xkcd.com/356/ Thoughts on the problem?

Homework Statement Microwave oven I. The glass window isn't important to the microwave oven's operation, but the metal grid associated with that window certainly is. The grid forms the sixth side of the metal box that traps the microwaves so they cook food effectively. What is the approximate...

Hi there, I am plotting some data onto a hammer plot using ipy- matplotlib. The axes on the plot range from alpha= -pi:pi and beta=-pi/2:pi/2. I have a value (lets call it delta) for each point on the plot where (alpha=integer,beta=integer). I have arranged the delta values in ascending order...

Hey iam trying to place some text in each grid in a grid field and also to fill each one with different color can anyone please help me out...

Short Circuit Current Hi, I am reviewing a ground grid study of a substation for a wind farm that is being built. The ground grid will be for a substation with a low side of 34.5kV and two transformers that step the high side voltage up to 345kV. There are six distribution feeders on the...

By now we have heard of all of these fascinating new technologies "just around the corner" that will "remove our energy dependence on corporate and foreign resources." In nearly every cable news interview, researchers claim that this new technology is "only five to ten years away." As a nation...

Hi I'm trying to deepen my conceptual knowledge about electrical systems. I'm definitely a lay level, tradesman level user here. I'm lucky if I can do some simple algebra, so I don't want a lot of math (though I might get into that later if I want to get deeper into engineering). I have...

I have an interesting finding in spacetime diagram - The area of the square grid for the rest frame O, is the same as the area of the rhombus grid for the inertial frame O'. More specifically, the area of the square for frame O (0, 0), (0, 1), (1, 1) and (1, 0) is 1 The area for the...

Homework Statement Hi, I need to calculate the voltage drop in an n by m grid. There are resistors 4 resistors connected to a square; R1 for horizontals and R2 for verticals. There's a voltage applied at point B and point A is grounded. I need to create a MATLAB function that will solve for...

1. Question Statement: Create a 40 mm by 40 mm two-dimensional grid centered on point (0,0) (grid size 1mm by 1mm so the grid is 41 points by 41 points). On this grid, put four circular electrodes, one centered on each corner, each with radius 15 mm. Fix the electrodes on the upper left and...

Frank Wilczek has presented a way of looking at the world which is curiously consonant with Lattice Quantum Gravity approaches a la Renate Loll, John Barrett, Lee Smolin, Carlo Rovelli and others. The world as lattice---what Wilczek calls the Grid. It is oddly reminiscent of spin networks...

I have made a Solar collector out of a 10' diameter satelight dish and lexan mirrors. I have a collector that converts water to steam ( 20lb propane tank) at a rather frightening rate I must add. Now i have a dilema. Where can I buy a turbine that i can bolt onto this scary steam source...

Is it possible to use an image as a background to a function graph in Geometer's Sketchpad, so that I could superimpose a grid over a map? Does anybody have an alternative suggestion if that's not possible in GSP? Thanks, -tubegeek

Homework Statement In a 6 x 4 grid (6 rows, 4 columns), 12 of the 24 squares are to be shaded so that there are two shaded squares in each row and three shaded squares in each column. Let be the number of shadings with this property. Find the remainder when is divided by 1000. There is a...