What is Structure: Definition and 1000 Discussions

A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as biological organisms, minerals and chemicals. Abstract structures include data structures in computer science and musical form. Types of structure include a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space.

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  1. I

    Fine Structure Effects: Physical Interpretation

    I was just wondering what the physical interpretation is of 'fine structure effects'? (where alpha is the fine structure constant).
  2. Q

    Fascicle Arrangement & Muscle Structure: Videos & Info

    How is fascicle arrangement linked to muscle structure? Does anyone know where I can get videos on fascicles? Thanks
  3. N

    Validity of Direct Product Structure of Symmetry Group

    In short, if we consider the group of symmetries of a regular octahedron, we see (or at least, the author of "Groups, Graphs and Trees" saw...) that the group is isomoprhic to Z2\otimesZ2\otimesZ2\otimesS3 - particularly since if we break up the vertices into 3 groups of front-back, top-bottom...
  4. D

    Understanding Protein Structure: Levels Explained

    What is the difference between levels of protein structure ( Primary , Secondary , Motifis , Tertiary , Domain and Quaternary )
  5. A

    Problem For Structure of Nuclei - Enigmatic

    Problem For Structure of Nuclei -- Enigmatic ! Question :- calculate the distance of closest apprach for a head on collision between 5.30Mev alpha particle and nucleus of a copper atom? Answer The distance of closest approach is given by...
  6. S

    Methods for determination of structure of solid?

    Hi, just a basic question , what are the main methods of determining the structure of a solid in order to test its genuinety i.e. gold... if i were to be given a piece of gold, how would i check that it is genuine gold? could i use x ray diffraction (If so what measurements /tests would i...
  7. K

    Making free bodies of a static structure

    Homework Statement The problem is this. We have a structure (see the attached image) and need to make freebodies of all of the members. 150 lbs are applied to the platform being lowered by the strings. We also need to figure internal stresses, but I think I can get those if I can understand...
  8. 1

    Help: Planck Scale and Fine Structure Constant

    Could someone explain the relationship between the FSC and the Planck Scale? What are they in relation to each other. I know what the Planck Scale is, and I even have a loose understanding of the FSC, but what of them in contrast and comparison? And how does the FSC affect QM, if at all...
  9. T

    Band structure and fermi liquid

    Hi everyone! I wanted to ask if in your opinion is it right to say that band structure calculations (and hartree fock calculations) could live in a framework of the fermi liquid theory where quasiparticles are one-electron states (which could be or not could be the case)...
  10. R

    Understanding Structural Design Approximations: Weight vs. Load Analysis

    I don’t understand what our teacher means by this: " Analyze the correctness (or lack of it) of a common approximation made in structural design, which is that the weight of the structure can often be neglected when calculating the loads carried by the members in the structure."
  11. B

    A question in Lewis structure?

    a question in Lewis structure? I know that Lewis structure is so easy to discuss ..but I have this compound : SnCl2 when I drew the Lewis structure of its , I had to make Double bond between the Cl & Sn ..but a teacher told me once that when the Cl is not the central atom it can just make...
  12. A

    May i know is structure such as bcc, fcc depends on how it process?

    i study from some books that the properties of a materials depends on the structure of it, while the structure depends on how it being process..may i know what structure actually it means? i can't get its meaning..does it means the processing methods will influnce whether the materials will be...
  13. M

    Understanding NMOS & PMOS: Structure & Application

    Homework Statement Please tell me about NMOS and PMOS, What are their Structure and Application Homework Equations The Attempt at a Solution
  14. K

    Show the reflections over the line do not have group structure?

    hey, how can ı show the reflections over the line do not have group structure? --reflection of the real plane ------
  15. S

    Crystal Structure Lattice Problem

    1. Homework Statement Using the powder XRD data below, show that the substance has a face centred cubic structure. (xray lamda = 0.154056 nm) Peak No.------2(theta) 1 -------------38.06 2 -------------44.24 3 -------------64.34 4 -------------68.77 5 -------------73.07 2...
  16. S

    Determine crystal lattice structure from powder XRD

    Homework Statement Using the powder XRD data below, show that the substance has a face centred cubic structure. (xray lamda = 0.154056 nm) Peak No.------2(theta) 1 -------------38.06 2 -------------44.24 3 -------------64.34 4 -------------68.77 5 -------------73.07 Homework...
  17. S

    Resonance structure of nitrous oxide

    I was asked to draw the resonance structure of nitrous oxide and given some bond length. So i need to eliminate non-probable resonance structure for nitrous oxide. I was able to draw three structure but how do we use the bond length to liminate non-probable resonance structure for nitrous oxide?
  18. P

    Construct an Egg-Safe Structure with Newspaper and Masking Tape

    Alright. Um. We have 4 sheets of newspaper and 1 meter of masking tape. We have to design a structure to catch four eggs dropped one after another from a point at a height of 6 ft. What do you guys think? We've tried making just a simple 'basket' filled with crumpled paper and it doesn't...
  19. S

    Would Dinitroacetylene be more explosive with additional oxygen atoms?

    Would the structure of Dinitroacetylene be... NO2-C(triple bond)C-NO2? If the triple bond makes it prone to exploding then woud something like NO2-O-C(triple bond)C-O-NO2 be even more explosive?
  20. J

    PLEASE Help - interpreting an Atomic Structure question

    Homework Statement It commonly happens that the hyperfine structure in a transition is dominated by the contribution of an s-electron in one of the levels. What property of s-electrons could be responsible for this? A transition of this kind occurs at 494nm in singly ionised 133Cs between a...
  21. V

    All mathematical structure exist.

    Modal realism! 1. All mathematical structure exist necessarily. 2. Our universe/multiverse is a mathematical structure. ------------------------------------------------------- A) Our universe/multiverse exist necessarily. Consciousness 1'. All mathematical structure exist...
  22. D

    1H NMR & IR : unknown structure determination

    Hi all, I was struggling in solving this question which is a part of a practice exam, and I need you to be patient with me and teach me step by step how to figure out the structure and how to read and analyze the spectra. I attached the two 1H NMR & IR spectra so you will be able to know...
  23. S

    My misunderstandings about protein structure

    Ok as the title suggests I want to clear up my misunderstandings on protein structure. 1. When they say primary,secondary,tertiary and quarternary structure do they mean different stages of a protein. What I mean is do all proteins have a tertiary or quarternary structure and are...
  24. T

    Analytical Calculation/Optimization of Ironless Motor Structure

    I'm interested in calculating (followed by optimizing) the uniformity of a magnetic field generated by an array of neodymium magnets. Let us assume we have an array of neodymium bar magnets, -each with a constant depth (10mm) and height (2300mm). -Multiple segments (with alternating poles)...
  25. B

    Constructing Structures with Cardinality W2: A Puzzle in Model Theory

    I was reading Hodges' Model Theory when I came across this question in the first chapter: Specify a structure of cardinality w2 which has a substructure of cardinality w but no substructure of cardinality w1. (Working in ZFC) I am assuming w2 means 2w1 but I'm not sure. I haven't really...
  26. P

    Space station - tension of the structure

    There is a space station of the length L and uniformly distributed mass M on the low Earth orbit. One side of it always faces the Sun. Which tension will the structure experience? My attempt of the solution: bottom of the station is L/2 meters below the stable orbit at that velocity...
  27. D

    Just wondering about the structure of a determinant

    Just wondering about the "structure" of a determinant... How much can a determinant tell you about the entries of a matrix? How much more if you know the size of the aforementioned matrix? How much more if you know that the matrix is symmetric?(perhaps a silly question). How much more if you...
  28. M

    Choose those statements that are true for the most stable resonance structure

    Dont have to be mean?
  29. M

    Thank you!Lewis Structure Problems

    Lewis structure (Related! - Please Help!) I have 2 problems, please help me!please! thank you so much! Homework Statement Can you tell me if I am correct?Thank you so much!I tried acd and ac but it's wrong! :( 1. Which of the following are true about the correct Lewis structure of the SeF2...
  30. J

    Exploring Topology: How Can Local Theory Affect Global Structure?

    Many interesting proofs in GR (regarding black holes and singularities, etc.) involve topological methods. However, I don't understand how a theory embodied in Einstein's equations, which appear to me to be local rules of evolution, can ever change the topology since a patch of spacetime...
  31. N

    QFT Recipe: Outlining the Formal Structure

    I understand that the formal structure of QFT has resisted axiomatization (so far) and that what formal structure presently exists is really a set of recipes. Can somebody outline the recipe please.
  32. X

    Thermal Expansion of wires within a structure - see picture

    Homework Statement dB = 12mm (0.012m), dC = 20mm (0.02m), E = 140GPa and the coefficient of thermal expansion, α = 12e-6/°C. Homework Equations δ = (R*L)/(E*A) The Attempt at a Solution Please see picture for my attempt. I don't know how the thermal expansion, which...
  33. N

    Structure Factor for non-Integer miller indices

    Hi all. I am a PhD student in a condensed matter group. Consider: I observe superlattice reflections due to ferrimagnetic order that requires one cell parameter to be multiplied by M, the next by N and the third by O . In other words, the magnetic order is described by a magnetic unit...
  34. Helios

    Quark Physics: Nucleon Structure Explained

    Quark physics is completely out of my depths but I was wondering if, in a nucleon, they assume certain orbitals like s,p,d,f, ... Does one quark tend toward the center? Is there a valence quark? Do any symmetries form?
  35. U

    The structure of quantum geometry of spacetime at the Planck scale

    http://img233.imageshack.us/img233/5816/espaotempoquntico1.th.jpg Two pictures of quantum spacetimes... The theory of quantum gravity (LQG) can perform calculations and predictions on the concrete structure of space and time at the Planck scale. Equations formulas that describe...
  36. P

    Cis and Trans Isomers of 2-Butene

    Homework Statement CH3CH=CHCH3 What's the cis and trans structure name for this formula? Homework Equations The Attempt at a Solution I've drew the ciis and trans structure H\ /H C = C / \ CH3 CH3 this is the cis the tran is similar to...
  37. C

    Which structure is correct according to its name?

    HI, A chemical has a name of Bis(2-ethylhexyl) 1,6-hexan-1,6-diylbiscarbamate, I wonder which structure is correct (sorry it seems like I can only paste smile strings, You can see the structures by depicting them on http://www.daylight.com/daycgi_tutorials/depict.cgi)...
  38. P

    Lewis Structure: SOCl2 Solution

    Homework Statement write lewis structure for SOCl2. Homework Equations The Attempt at a Solution .. .. .. :Cl-S-Cl: .. | .. :O: .. what i did was put S in the middle with a single bond on both side for Cl, each Cl has six dot. S has two at the top. I...
  39. F

    Muon decay and internal structure of leptons.

    Hi, Could someone tell me please what is the scientific consensus(or some interesting theories) on why do muons decay and what is the mechanism of it? My understanding of particle decay is based on for example neutron wchich decays because a quark in it flips from down to up. But leptons, if...
  40. Q

    Determine if BCC or FCC structure

    Hey guys I've got a question and I am not sure how to go about answering it without looking up a table of characteristics of elements! Niobium has an atomic radius of 0.1430nm and a density of 8.57g/cm^3. Determine wheather it has an FCC or BCC crystal structure? Now i think you have to...
  41. A

    Designing a Flexible Structure to Hold 150kg Load

    Hi, I am searching for a structure that would take a load (150kg). The problem is that I want it not to break (Sigma=P/A) but I want it not to be stiff (K=AE/L). The only parameter I have is the area A but it is opposite in the equations (I can't really change the length and I did not...
  42. M

    Intersection-find Data Structure

    Is there a data structure like the union-find data structure, but for intersections (and the sets needn't be disjoint)? I'm looking for a data structure that stores an indexed set of sets A_1, A_2, ..., A_n, and supports the following operations: replace the sets A_i, A_j with their...
  43. L

    Why is linear algebra essential in understanding quantum mechanics?

    Hello! I have noticed that most advanced textbooks on QM start the development of the subject with a long review of linear algebra. In particular, they talk about pre-Banach, Banach, pre-Hilbert, Hilbert spaces and so on. Why is it necessary to invoke such abstract spaces in order to describe...
  44. G

    Upwards buoyancy pressure only acts on the surface of a structure that

    so with buoyancy and liquid pressure i am pretty sure i know the answer but i just want to confirm (please don't laugh if it's obvious) - upwards buoyancy pressure only acts on the surface of a structure that is faced down - the bottom of the structure that supports all the mass of the...
  45. N

    Structure of Minkowski Space

    In another thread Fredrik referenced THE RICH STRUCTURE OF MINKOWSKI SPACE at http://arxiv.org/abs/0802.4345..(The math is NOT simple!) But the introduction got me wondering... around page three is this statement: So what knowledge regarding more exact models of spacetime and the relativity...
  46. M

    Electrons' Angular Velocity in Atomic Structure: Examining the Same V?

    In special relativity the clock hands velocity is represented by: V = v0*(1-v2/c2)^1/2 then: What happen with electrons angular velocity in atomic structure? It may be the same?: V = v0*(1-v2/c2)^1/2 if this could be true what happen with matter?
  47. A

    Advice on stabilizing a tall wooden structure (just a fun/simple project)

    The structure in question is a diving (read: jumping) platform that my father and I built. Here are some pics: All measurements/approximations were made in feet or inches, so I'll present them in that form if it's not too much of a problem: The...
  48. A

    Electronic Structure (magnetic quantum number)

    Homework Statement Describe a possible set of quantum numbers for the 44th electron in mercury. The Attempt at a Solution I can't help but feel a bit embarrassed by some of the questions I ask on this forum. Nevertheless, I am having problems with figuring out what the magnetic...
  49. J

    Structure of Romantic and Sexual relationship

    ...from a sociological survey conducted in Jefferson High school. http://researchnews.osu.edu/archive/chainspix.htm Does the big circle represent their football team? :)
  50. H

    Is This Resonance Structure Valid?

    Is this valid: http://img197.imageshack.us/i/imagecct.jpg/
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