Construction Definition and 254 Threads

I do not know if this is the proper rubric to ask this question, but I picked the one that seemed the most relevant. I have noticed some superficial resemblance between the tensor product and the ultraproduct definitions. Does this resemblance go any further? While I am on the subject of...

divide a circle into 9 parts with equal area

I have found a way to construct a pentagon using only the grid system. The internal angles are all within 99% accuracy and all the angles to the 3rd decimal add up exactly to 540 degrees. This is without the use of a compass and bearing in mind that the internal lines intersect at the ration of...

<< Disclaimer by PF -- You may need to get government permits to operate a reactor that produces neutrons and radiation, and this could potentially be a dangerous project >> Hello, I recently finished building a functioning IEC fusion reactor and posted a video of its construction and...

Hey folks. I've done a little bit of research into model rocketry and I'm stuck with the idea of designing and projecting a rocket to put into practice all the engineering I'm learning in college - I'm into MechE. I want to start simple, doing a few tests and learning the basics - types of...

I was helping with a disaster preparedness presentation at a local elementary school last night, and noticed this fence gate in front of the school. I'm not an ME, but it looks to me to have a small problem...?

Very basic issue here. Using: \frac{1}{1-x} = \sum_{i=0}^{\infty} x^{i} , |x|<0 Find the power series representation and interval of convergence for: f(x) = \frac{1}{(1-3x)^{2}} We have that: \frac{d}{dx}\left[\frac{1}{1-x}\right] = \frac{1}{(1-x)^{2}} = \sum_{i=0}^{\infty} ix^{i-1} ...

So, this is the old way in how AND and OR gates are constructed based on transistors, I want a revolutionary way that AND and OR gates can be constructed based on light without anything software like if and else statements. Thanks fellow engineers

Hello! (Wave) I want to construct the field $\mathbb{F}_{3^3}$ and find a generator of $\mathbb{F}_{3^3}^{\star}$. I thought to consider a $t \in \mathbb{F}_3[x]$ where $t$ is irreducible and $\deg t=3$. So we consider $t=x^3+x^2-x+1$. Let $b$ be a root of $t$. Then $b^3+b^2-b+1=0...

cool article on the progress of the JWST constructionhttp://www.space.com/31838-james-webb-space-telescope-mirror-assembled.html?cmpid=NL_SP_weekly_2016-2-05Dave

Homework Statement The familiar Mercator map of the world is obtained by transforming spherical coordinates θ , ϕ to coordinates x , y given by ##x = \frac{W}{2π} φ, y = -\frac{W}{2π} log (tan (\frac{Θ}{2}))## Show that ##ds^2 = Ω^2(x,y) (dx^2 + dy^2)## and find ##Ω## Homework Equations...

Homework Statement In En the quantities Bij are the components of an affine tensor of rank 2. Construct two affine tensors each of rank 4, with components Cijkl and Dijkl for which ∑k ∑l Cijkl Bkl = Bij + Bji ∑k ∑l Dijkl Bkl = Bij - Bji are identities. Homework Equations The Attempt at a...

I'm looking to find someone who can give me a quote on cost to make tracks and a motorized camera car that can run along the tracks at a specified speed. I can provide more details about the project if anyone is interested in putting together figures to give me an idea what this would cost, so I...

Homework Statement We have a slab with uniform distrubuted load on it W. All dimensions. [/B] I'm looking for the force on the bolts and force on the hook contact surface. The Attempt at a Solution My way to do it is to reduce the problem for 2D. But the problem is that I'm not sure how to...

Hi everybody, I am new in this forum, and i have to say that i am not the best in physics but, i always loved playing with paint, carbon fiber and fiberglass etc... I had an idea of trying to make a Helmet with a science-fiction look ( halo ) and make it legally to wear it ( In thailand ) I...

Hi all, first post here. I'm currently faced with an assignment in a class where we really haven't been taught anything and have to figure it out on our own. We've been asked to design an industrial lift system to raise approximately 3000 kg up 25 stories. I have done a lot of research and...

I'm looking to roof over my backyard deck. I have particular desires for it. It must - let in light - be rainproof - not reflect sound well - be bug-unfriendly (more on this) Most of the materials that are transparent and rainproof are also hard, and thus reflect sound efficiently, meaning it...

For a recent project, I would like to construct a small-scale HIFU system to be focused onto a small sample, ideally inducing an oscillation (velocity) of around ~1000 cm/sec. However, upon researching into this topic, I've only really found information on systems used for medical applications...

This is just a random thought, may be totally wrong. Euclidean geometry was originally described as a constructive theory in which the axioms state the existence (and implied uniqueness) of certain geometrical figures. These constructions are the ones that can be done with two concrete tools: a...

Hello to all, glad to be here. I have a sort of general question about the construction of a small, rod shaped, battery powered (2 9volts), heating element, that will keep approximately 4 ounces of fluid at a steady temperature between 95 and 100 degrees Farentheit. The heating rod will need to...

Would SS304 or SS316 be a better choice for a reactor containing 200 kg/hr sulphuric acid (97%), 2000 kg/hr methanol (98%) and 3500 kg/hr free fatty acids mixture? My initial choice was SS304 since the sulphuric acid amount was little, but upon reading more on methanol, I'm considering about 316...

I'm trying to build a high gain TV antenna. I'm looking to achieve a 75 mile minimum range under most weather conditions. I do have a signal amp board I striped from an OK antenna, that I plan to use as well. I'm trying to specialize the antenna for my viewing market, UHF channels 17-38 (489.25...

There is a general topic of boundary constructions, which means how to adjoin idealized points in a sensible way to a given spacetime. There is a menagerie of these methods, including the g-boundary (Geroch), b-boundary (Schmidt), c-boundary (Geroch, Kronheimer, and Penrose) and a-boundary...

I want to known the stator design of an indiction motor. How may turns required for each pole. For exmple if a single phase motors is designed to run at 230v ac, how may turns required in each pole. If the same motor is designed to be run in lower voltage (say 110v ac or 12v ac) what will be the...

what is the difference between the construction of a power transformer and a pulse transformer used in high frequency application and what about their core and copper losses?

Annals of Physics August 2015, Vol.359:80–96, doi:http://dx.doi.org/10.1016/j.aop.2015.04.016 Exact solutions of the Wheeler–DeWitt equation and the Yamabe construction Eyo Eyo Ita III Chopin Soo Show more Abstract Exact solutions of the Wheeler–DeWitt equation of the full theory of four...

Hello there, I again have a problem with programming in Fortran 90.1. Homework Statement I would like to construct an array with an implicit do loop. I know how to get the array I want to with usual do-loop but I would like to do it without do loops. So this is the array I want to construct...

I have some question about RICH detectors (in particular HERA-B RICH) and why are they constructed in such a way...I think all the RICH detectors though use the same construction that "confuses" me. In their case the particle of some unknown velocity ##\beta## enters the gas of known refractive...

I am reading about the construction of the path integral in which states that the propagator is given by: <qf l exp(-iHt/ħ l qi > = ∫Dq exp(i/ħ∫dt L(q,q')) and Dq is the integration measure given by limN→∞Πn=1N-1 dqn. Can someone help me understand this integration measure a bit better? I...

Consider an Ising model system where the total energy is ##E = −J \sum_{<ij>} S_iS_j ##, ##S_i = \pm 1## and ##< ij >## implies sum over nearest neighbours. For ##J < 0## the ground state of this system at ##T = 0## is antiferromagnetic. (All adjacent spins misaligned so net magnetisation zero...

Homework Statement State the null and alternative hypotheses. The decision to implement changes in the current math program at a junior high will be based on a sample of students' scores on a standardized math exam. If the average is less than the statewide average of 89, all math teachers...

Homework Statement Beams AC and BD are light (no mass) and they're conjoined at B. Points A and D are fixed but frictionless. The radius of the wheel is R and the weight hanging on the pulley has the mass m. Homework Equations Fx=0 Fy=0 M=0 The Attempt at a Solution I'm stuck at the very...

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > I have to design similar bogie to one shown above. It's is used on straight rail. I am not sure what kind of construction I should use to connect body to axles. More simple solution -...

I need to construct a cauchy sequence ${r}_{n}$ such that its rational for all n belonging to set of natural numbers, but the limit of the sequence is not rational when n tends to infinity. I know that all convergent sequences are cauchy but I can't randomly conjure up a sequence that satisfies...

Hi, Right now I am in my 3rd year of a dual construction management and environmental engineering degree. I have an interest in building things (both design & construction), but more important to me is a career with a high income and quality of life. I am debating between a structural...

Hi there, i am currently working in an airline industry but unfortunately do not have enough facilities to carry out my research on the HPT Blades and its cooling holes of an Engine. Would anybody help me on this matter? Thanks

Hello Big Minds, In the following analysis...It is said that D_2 contains three subgroups Z_2...why did he choose a mathematical constuction contains only two of the the three subgroups? shouldn't he use the three in his construction? what will happen if he used the three? [from the book of...

Hello, I have made a capacitor with two aluminium foils separated with paper dielectric with, dielectric constant (K) = 3.8 for paper material paper thickness, D = 0.1mm = 1e-4 m plate or foil area, A = (12.1 x 8.3)cm = 0.010043 m air permitivity, Eo = 8.85e-12 F/m Calculated capacitance = (K...

There is wet-bulb temperature of 69 centigrade in the picture which I cannot understand how it is placed there and what is the relation between it and saturation line (RH of % 100) Thank you

What's a suitable Material of construction for equipment handling hot brine (NaCl) solutions? Temperature is max approx. 100 C. I'm conflicted if or not SS316 works? I looked up an old handbook and it reported a corrosion rate of 0.2 mm/year (@80 C) which seems not too bad to me. But I've...

What do we mean by "there is no local construction for an action in terms of F^{\mu\nu}, or E and B"? So, I understand the construction "on-shell", once we solve Maxwell's equations to find F^{\mu\nu}=\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu}, and how we can then write an action which is both...

Evening, gentlemen! Just a quick question for you guys... maybe more, if anyone's seriously interested. I've got a project going on at the university that I hope to get funding for in the future, which is the construction of a relatively small Bitter electromagnet. I say 'relatively' because...

Homework Statement A construction worker attempts to lift a uniform beam off the floor and raise it to a vertical position. The beam is 2.26 m long and weighs 397 N. At a certain instant the worker holds the beam momentarily at rest with one end a distance d = 1.21 m above the floor, as shown...

Hello, I am constructing a clinostat for an Experimental biochemistry research project. Physics is not my forte, and as such I would like advice on what type of low torque motor I need to rotate an 85g cylinder at ~60rpm. A diagram of the design I am using can be found here...

I've worked that out in my Mathematica notebook "Lie-Algebra Matrices.nb" in directory "Extra Mma notebooks" in SemisimpleLieAlgebras.zip, but I must concede that some of my derivations seem rather inelegant, not using features of the algebras very well. The last comment in How should I show...

I often enjoyed how when you shape an object with clay and blast it with a furnace, you would be able to turn the soft material into one where you can store water and heavy objects inside, and be resistant to some external forces as well. Thus, it make me wonder if there are materials that...

Definition/Summary The Cayley-Dickson construction is a way of getting algebras from other algebras. The starting algebra must have addition, multiplication, and conjugation defined for it, and the new algebra has pairs of elements of the starting algebra with appropriately defined operations...

in Appendix D, pp. 179 ff, of Alain Conne's "Noncommutative Geometry", he outlines a process. He looks at Penrose tilings of the plane which are composed of two types of triangles L [with 2 longer sides of length \phin+1, and one shorter side of \phin) for integers n, whereby \phi is the...

1. Metallurgy. How much pure gold should be melted with 15 grams of 14-karat gold to produce 18-karat gold? 2. Road Construction. A new machine that deposits cement for a road requires 12 hours to complete a one-half mile section of road. An older machine requires 16 hours to pave the same...

I did a cursory search on the forum, and I browsed Wiki...but maybe I missed it. What is that big Flap/Door on the end of the scope.? Is it part of the optics, or is it a protection device, or a...? Thank You