Structures Definition and 324 Threads

A chain hanging from its ends forms a shape called a "catenary". This shape is perfect for a self-supporting arch, because the bending moment is zero at each joint. (If there was any bending moment on any joint to start with, it would have changed shape until there was no more any bending...

Greetings, I am almost 70 years old now, and have retired from formal employment. This was no my decision, but Company policy. I've been making stuff since I was knee-high to a grasshopper. Not everything worked out first time... I love hydraulics, and structures with triangulation. I have built...

I'm waiting for PADME run 3 and MEG II from Russia not Hungry could someone review arXiv:2311.18632 (hep-ex) [Submitted on 30 Nov 2023] Observation of structures at ∼17 and ∼38 MeV/c2 in the γγ invariant mass spectra in pC, dC, and dCu collisions at plab of a few GeV/c per nucleon Kh.U...

Do you know any such good resources? I want to improve my problem solving skills. I also want to practice competitive programming, so any good courses for that? I want to practice pointers any good courses for that?

Concerning cosmological structures (like galaxies, clusters of galaxies, gas bodies, superclusters...etc) if the elements that make them are close enough they will be attracted towards each other by gravity. Contrarily, if they are sufficiently far apart they will get further away following the...

I have tried to calculate the safe load with the equation of maximum shear stress, A = 4*6*10^-4, and the given shear stress 5MPa, but I couldn't seem to get the right answer which is 18kN.

Figure: My attempt at a Solution: We calculate REACTIONS: $$\sum F_x=0\rightarrow \boxed{Bx=0}\qquad \sum F_y=0\rightarrow By+A=50$$ $$\sum M_B=0\rightarrow \boxed{A=25\, \textrm{kN}}\quad \boxed{B=25\, \textrm{kN}}$$ KNOT B: $$\alpha \rightarrow \alpha =90-40=50\, \textrm{º}$$ $$\beta...

[Moderator's note: Spin off from previous thread due to more advanced level of discussion.] The above is true even on an ordinary position-vs-time graph in PHY 101, when "distance" is appropriately defined. OOPS (Thanks @PeterDonis ) This turns out to be true only in the Galilean/Newtonian...

I am learning about 3 V's of big data. I am learning about variety at the moment. They say variety represents variety of formats, data sources and structures. I understand format might be txt, audio, video files etc. Sources might be different sources of data. But what is structures of data? I...

Summary:: Please see picture below The dotted line at Test 3 means to continue using the above solution, and add NaOH with the teat pipette. The dotted line separating tests 3 and 4 should be a hard line, which means to use a fresh sample of FA10 and perform the test. It is also known that...

Summary:: I would like to know if my answers of each resonance structure of the eight questions is correct or not. I think the Inductive effect (induction) attracts electrons and affects up to three bonds as electron attracting group. And the Mesomeric effect affects Pi- bonds as long as there...

Can a compound have multiple structures? For example, I found two different versions of Sodium dichloride (Cl2Na-). https://pubchem.ncbi.nlm.nih.gov/compound/22590707 https://pubchem.ncbi.nlm.nih.gov/compound/57736105 What makes the difference between which of these compound structures is...

Hi all, I have the following situation: I need to determine the minimum force needed for a motor to move the load (75 N) at the end of the beam. I added the forces in a FBD and did the sum of forces and moment calculations (see below). Is this calculation correct and what would be the next...

This questions is hovering on my mind from a long time. Why would something which does not have life would want to be in such a beautiful neighborhood, while the world is so much disordered. What causes them to be in that regular array and how they choose which crystal structure is suitable for...

Is there a general rule for a crystal structure how many bonds each atom in the crystal lattice will make ?For example Si has a face centered cubic structure so it makes 4 bonds regardless of the fact Si has 4 valence electrons?

What is a boundary and how can boundary interactions be used in echolocation and examining internal body structures?

The adjective "finite" applied to many algebraic structures (e.g. groups, fields) indicates a set with a finite number of elements. However, (as I understand it) "finite algebra" refers to a finitely generated algebra. Are there other examples where "finite" means finite in some respect but...

How would I name the following two compounds? My guess is that the first one would be 3-bromophenyl 1-chloro ketone and the second one (4Z)-3-sec butyl-hex-4-en-1-yne. Am I correct? Thank you

Here's a nice video which is a size comparion of a great number of fictional structures from science fiction novels, movies and games. The video is called "FICTIONAL STARSHIPS Size COMPARISON" but it includes some structures I personally wouldn't call starships, but anyway... Enjoy...

Hello, In Python and other programming languages, data can be of different types: integer, float, string, Boolean. On the other hand, Data structures are containers of data items which can (or not) have the same data type. A variable, when created, has: a) name (a piece of data stored in...

Hi, I'm new to PF, but was hoping that there might be people on this forum with an interest in Taxicab numbers, particular on the "structure" of such integer sequences. If yes, would be delighted to hear from you.

Summary:: I have recently started with data structures in java and I tried doing this Program .But I have few confusions. 1.How do I write the main() of the program? 2.What are we supposed to do with the value returned by function pop()? If anyone could point out if there are any errors and...

I have been watching lately many YouTube videos on megalithic structures. I am talking about the most ancient stonework in South America where the stones are cut and fit almost perfectly. These stones have many common features. They are cut to fit almost perfectly. They are all beveled at their...

For organic chemistry, what is important to memorize when I am reading a textbook? Should I memorize the structures and names of different organic compounds when they are described as examples? Or is it more important to memorize the organic reactions? Also, does anyone have any tips on how to...

Hello! In the context of Python, indentation is very important and mandatory. The entire code is separated into blocks and each block has its own indentation. Two blocks with the same indentation belong are the same block unless the blocks are separated by a block with less indentation...

Hi all, Trying to right a program in Python asking user to guess a number ( integer in finite range) until they make a correct guess, though I want to warn user when guess is too high --asking that they choose a lower number ,and same for when the guess is low, asking them to choose a higher...

I have drawn structure of purines and pyrimidines literally 14 times but still I am not able to recall the structures of these tiny monsters after few days of learning them. Can you please tell me how you remembered these structures. Thanks😃.

If you do the sum of vertical forces and sum of moments, you're always left with an unknown. Vertical Forces: Ray + Rby + Rcy = 59kN + 45kN (1) Sum of Moments about A: (59 x 1.85) - (Rby x 3.7) - (Rcy x 4.8) + (45 x 6.5) = 0...

I've been looking over precedents for a design project and I noticed that the most commonly used systems are either steel or reinforced concrete structural systems. Is it possible for a steel structural system to be connected to a reinforced concrete structural system? If so, how does it work...

Hey guys basically why are copper crystals more conductive then the corresponding amorphous structure? I know generally that electrical conductivity is reliant on: σ = (e2 * (vf)2 n τ)/3 My attempt of understanding is that the crystal structures are made up of unit cells which implies every...

I have a quesrion about forming the eqaution of moment equilibrium. As shown in the picture at cut 1 there are 2 vertical forces and a bending moment. I expect V=A. If I apply moment equilibrium about the point where the bending moment is, we get that Ay*x = M(1). But how about if I take moment...

What's the best software to use when designing 2D floor plans for structures?

As in constructions that consist of a membrane of some textile and are sustained by pressurized air bombs. A paragraph mentions that in the face of strong winds or snowfall the internal pressure rises... but i don´t understand exactly why is that. I´m just curious and would like to know. pd...

I can't understand how dark matter can form structures from the initial near uniform distribution as shown in simulation like those of the Eagle project http://icc.dur.ac.uk/Eagle/index.php. I understand how the initial density fluctuation are amplified and dark (and ordinary) matter start to...

We were asked to label the vasculature structures of a cucumber cross section (complex tissue). I just wanted to know if my labels were accurate. Image attached 1. Xylem 2.— 3. Sieve elements 4. Phloem

Summary: Could a hierarchical structure of protons, muons and positrons be stable without the weak interaction? This discussion started here, I quote the relevant previous comments and then reply: @Vanadium 50: (mu- e+) is muonium, not true muonium - it is hydrogen-like where the muon...

I know that direct interaction of opposite chirality(?) particles results in annihilation(eg. proton and antiproton). And I have read that proximity of quark and antiquark, even if in separate subatomic particles, results in at least partial annihilation(eg. Antineutron and proton). But I am...

Imagine a 400-meter-long pipe with a 1600-meter diameter, floating in inter-planetary space. It is spinning at 0.5 gravity along its major axis and there are no secondary-axes spins. We need to increase rotation to 0.85 g. Its density is a uniform 2.3 kg/m³ and it weighs 49,120,056 kg. Thanks to...

Hello All, I have a question regarding a MATLAB homework problem. I am learning about logical functions and selection structures. Here is the question: The height of a rocket (in meters) can be represented by the following equation: height=(2.13*t^2)-(0.0013*t^4)+((0.000034*t^(4.751)) create a...

Hello everybody, I am stuck with drawing resonance structures for different types of compounds. Do you know any tutorials or any methods to master drawing resonance structures? If yes, please be kind enough to drop some links and statements below. Thank you very much in advance.

Why do we have to memorize the structures of all the nitrogen oxides? Isn't there any way to understand about the Lewis structures of all the nitrogen oxides and their weird ways of making bonds?

Lie algebra theory is to a large extend the classification of the semisimple Lie algebras which are direct sums of the simple algebras listed in the previous paragraph, i.e. to show that those are all simple Lie algebras there are. Their counterpart are solvable Lie algebras, e.g. the Heisenberg...

Greg Bernhardt submitted a new blog post Intro to Data Structures for Programming Continue reading the Original Blog Post.

Homework Statement Which molecule is more acidic H2F+ or CH3SH2+ Homework Equations None The Attempt at a Solution H2F is more acidic as the answer. However, I was told in class that there were several factors affecting acidity, with some having more weight such as resonance>atomic radius>...

Suppose that there exists a rotating water planet, i.e. a planet with a fairly deep ocean, which contains a large structure of a particular geometry submerged within the ocean. If this structure was assembled within the ocean will it, once it reaches a steady state, rotate at the same rate as...

Dear experts, How should I compute the wind loads for a Shukhow tower, i.e. a circular cross-section steel lattice structure? The structural members should be rectangular or circular. I´ve been checking EUROCODEs EN 1991-1-4 (2005) and EN 1993-3-1 (2006) without success. Is there any other...

I am trying to understand diffraction on periodic structured in solid state physics.Q is the source of the spherical wave. R the vector to the object and R+r the vector to the scattering centre P, which gives us a another spherical wave. All spherical waves are considered as plane waves due to...

I am 2nd year physics undergrad. Just want to study a bit about materials in my free time. I have no idea about engineering books. Please suggest some good books. Thanks.

I have uploaded the picture of the structures because I couldn't figure out how to type. Its vinyl chloride. According to me the order should be I>III>II because I has no charge so it must be most stable in II we have Cl an electronegative element bearing positive charge which makes it...

Hello, The problem I came up with deals with the structures that can be obtained by joining squares side to side or corner to corner. Specifically to this problem, structures, that are symmetrical to each other, are regarded the same. Ideally, I am looking for a formula that will tell how many...