Construction Definition and 243 Threads

Understanding the construction of vector spherical wave functions! Hi guys, I'm looking at electromagnetic scattering just now, and in particular, how multipole fields are constructed and then how the wavefunctions are represented as the incident, internal and scattered fields. When you...

What is the best material to use for the bobbin (spool) to wind the copper wire around. I know plastic is used, but is aluminum any good for this? How do you determine which direction the rod will tavel through the coil without testing it first?

Can you prove that \mathbf{R} and \mathbf{R}-\mathbf{Q} have same cardinality? One way would be to say that \mathbf{R}-\mathbf{Q} is not countable and must have cardinality <= \mathbf{R} and invoke the Continuum Hypothesis to conclude that its cardinality is aleph-1 same as that of...

Hi, we often come across certain constructions in algebra that make use of some "formal" sum or "formal" linear combination or "formal" string of elements. Because this term is never defined, I have always been a little uncomfortable when it comes up. For a specific example, consider the...

Hi all! I am currently preparing for an oral exam in quantum field theory and particle physics and I have some problems with the SU(3)-Hadron Multipletts and the relation to the Gell-Mann-Nishijima equation: First, for SU(2) Multipletts you take your Casimir-Operator J, some commuting...

So I am trying to estimate blood velocity using Doppler ultrasound. We have a complex signal y(t)= i (t) + j* q(t). i(t) and q(t) contain unwanted high frequency components created by the demodulation process and low frequency signals that are reflections from stationary tissues. I need to...

The builders are here to renew my roof and chimney, so it is going to be two weeks or more of hell, heck knows if i will ever get any sleep while they are banging around, luckily a friend has offered a place to keep my bikes in safety.

can mankind do like the ISS and launch many sections of a orbital space-dock into the orbit and use these as a platform to build large ships required to transport people to other solar systems?

I'm watching a NOVA documentary "Secrets of the Parthenon", and the storyteller tries really hard to hype the ancient engineering technology, by saying our modern technology isn't capable of understanding/replicating what the greeks did. Is it me, or are they just suffering from the "garden...

Homework Statement A segment of interstate highwya under consideration lies in a vertical plane. A segment with a grade of -5% is to be joined smoothly to a segment with a grade of 3%. The vetical parabolic curve which will accomplish this transition is to begin at a point with elevation...

Suppose we had the technology to produce artificial diamond beams and carbon nanotube rope cheaply enough to use in large quantities. If we use the diamond for compressive load, and the CNT ropes for tensile load, how tall a skyscraper could we build using these materials, in theory? Is there...

Homework Statement A car starts from rest at time t=0 and accelerates at -0.6t+4 meters/sec^2 for 0\leqt\leq12. How long does it talke for the car to go 100 meters? The Attempt at a Solution Since it says the acceleration is -0.6t+4 I integrated it and ended up with v(t)=-0.3t^2 + 4t...

Homework Statement A 4m long, 500 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 70kg construction worker stands at the far end of the beam Homework Equations What is the magnitude of the torque about...

http://www.math.caltech.edu/classes/ma1a/Fa07Ma1aHW2.pdf Problem 2 (note, I'm not a Caltech student, so this is not a violation of the Honor Code - also, solutions have been posted) The solution to problem 2 is at http://www.math.caltech.edu/classes/ma1a/07Ma1aSol2.pdf The question with the...

I learned that given a vector space we can construct a basis for it. Can anyone give me an example of this thing (except the trivial example of 2-D and 3-D euclidean space.)

Does anyone have any information whatsoever about freeware or any other software that I might be able to use. I essentially need to input coordinates, and would love to have some program construct a visual representation for me to see. That would be swell! Thanks everyone!

Hi, I'm not really good at physics, that's why I truly appreciate your help on this one. I'm doing a project about optics, and I've never studied optics at school before, and because my time is limited, I had to skim through the materials so I'm not really sure if what I do is right...

The fractal sequence http://www.research.att.com/~njas/sequences/A054065 is of interest because it provides permutations of the numbers 1-n such that the decimal part of k*tau (k = {1,2,3,...n} is ordered from the lowest possible value to the highest. For instance if n = 3 the permutation...

1. Would it be true to say that everything of substance in the Universe is made up of various combinations of hydrogen atoms, with neutrons thrown into everything except hydrogen itself? 2. Are all protons, neutrons, and electrons made of the same material, and what is it called?? Atomic...

Oh my, this does change history quite a bit. The limestone blocks for the pyramids were formed onsite and not dragged by slaves or teleported by aliens? This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation. "A year and a half...

I know this is an engineering/physics forum but I was wondering if some of you could tell me more about this field. Although, I have frequently thought about civil engineering but after months and months of mulling over a decision, I decided not to pursue it (though I still go back and forth)...

Hi all, I'm trying to compute the axis forces in the construction I put to attachment. I already have computed the R forces, but I don't know where should I start computing the axis forces from, from which point. Could please someone give me some advice? Thank you very much, best regards.

I am having trouble figuring out how "heavy" to build a stand for a large aquarium. I have tried calculating "moments of inertia" and "section modulus" values, but frankly find myself lacking in the ability to work out my problem, this is quite frustrating for me. I like to think of myself as...

Hi, me and a friend of mine decided to construct a Roman Onager for school. This is because of some kind of (practical) exam every student has to undertake here in the Netherlands. For example.. some people study the effects of alcohol on the human body and others build a rocket and try to...

Homework Statement How is the construction of an ac ammeter different from that of a dc ammeter? Homework Equations The Attempt at a Solution

Constructions are or aren't able to hold? (tutorial) Hi everyone I have searched on google already and also on yahoo but couldn't find the tutorials which I am searching for, they are for mechanic - solidity (machine design of mechanical engineering - how much, what dimensions of specific...

(I am not sure whether I'm posting in the right forum. I apologize if I do) Does anyone have an alrorithm or a code (in any language) that constructs a Poincare surface of section? I want to do so for a Hamiltonian model: A mass under the influense of the Henon-Heiles potential. It has to...

Hi I am trying to figure out reactions in the mechanic construction which is here http://img.photobucket.com/albums/v309/Andreii/nalogca.jpg" . Datas of construction are: L1 = 7.1m L2 = 1m L3 = 0.2m F = 2.8 kN = 2800N M = 1.3 kNm = 1300Nm (this is torque) p = 2.5 kN/m = 2500 N/m p...

Hi all! It's me again. I asked about how the wing of a design car should be designed before. Thanks for all your replies. I would like to have a good reference book for me to start from scratch learning how to build a race car, do you guys have any recommendation? p.s. I major in...

Why is the GM tube polarised? What benefit comes from having the anode at the centre of the tube? What happens if you reverse the polarity?

for the construction of buildings which one is the best titanium aluminium iron cosider all properties DO NOT CONSIDER COST

Hurray for an alliterative title. I guess I'll have to apologize in advance if you don't like logic-type stuff, but I thought these were pretty cool! A Q-sequence is basically a formal-logic-like thing you can do in any category. The basic example is that of a diagrammatic definition...

Everyone knows (or does now) that gender is another socially constructed category. It is based on biological differences (which are real) such as differences in DNA, hormones, genitalia, sexual orientation, and overall appearance. Even the idea of what sex a person is is not always certain. A...

The other day, I (once again) decided that I simply don't understand natural transformations. (Or functor valued functors, for that matter... which greatly disturbs me because I'm usually quite comfortable with function valued functions) So, I sat down to try and figure them out, and I...

Does anyone have an idea of an innovation i could design to assist astronauts in the contruction of a space station? I really have no ideas, and am looking for something simple but really clever and effective. Help will be extremely appreciated :smile:

"Construction" of "number system" Hi everybody, How is the number system created and defined? I am talking about the natural numbers, but I am not actually asking about the definition and properties of N (Peano) but for the way that we have agreed to produce numbers. I mean, we have defined...

I can't seem to find much information on the construction of nanoshells. If anyone can post a link or briefly explain how nanoshells are generally created in a lab today, I would be very thankful. I'm supposed to write a paper on nanoshells and their impact on medical science. So any further...

I am trying to construct a wood platform that rotates both clockwise and counter - clockwise. It needs to be able to hold an adult and be propelled by an electric motor that can be operated from a short distance from the platform. It doesn't need to be fancy, I just need it to rotate people at a...

i'd like to know about the materials that were used to build the hull of the titanic?...i'v googled it,,, but i suck at finding info so bad, can anyone help?

For each ordinal number i, recurisively define: \begin{equation*}\begin{split} Z_0 = \{ \varnothing \} \\ Z_i = (\bigcup_{j < i} Z_j) \cup \mathcal{P}(\bigcup_{j < i} Z_j) \end{split}\end{equation*} Definition: A set S is a Z-set iff there is an ordinal i such that S \in Z_i...

hii I'm in grade 11 and this is regarding an improtant physics projectwhere i need to build a device/ transporter ( I'm GUESSING thst it should be something like a car)this device has to move and have a displacement of 5m north at least and it can obtain its energy to move only form a rubber...

Hello, I am having trouble understanding the solution to a problem. It should be straightforward but as usual it is not straightforward to me. Question: Construct a triangle ABC given side a, angle B, and the length of the median from C. Now, I first construct the side a (side BC). I...

There is the hydrogen bomb and there is the nuclear weapon that uses plutonium. As far as I know the atomic structure of hydrogen versus plutonium are at the opposite ends of the chemical chart spectrum. Hydrogen having the least atomic weight of all elements and plutonium having a very high...