Specimen Definition and 23 Threads

Archaeopteryx fossils from the quarries of Solnhofen limestone represent the most famous and well-known fossils from this area. They are highly significant to paleontology and avian evolution in that they document the fossil record's oldest-known birds.Over the years, twelve body fossil specimens of Archaeopteryx and a feather that may belong to it have been found, though the Haarlem specimen was reassigned to another genus by two researchers in 2017. All of the fossils come from the upper Jurassic lithographic limestone deposits, quarried for centuries, near Solnhofen, Germany.

View More On Wikipedia.org
Recent contents Top users
  1. blueboo33

    Find the force while lapping a specimen

  2. Y

    Notched specimen under constant K and temperature gradient

    Hello all, It seems like a fairly straightforward question but I cannot find any information in the literature. Let's suppose we apply a crack driving force K1=45 MPa.m^0.5 to a notched specimen with an upper shelf fracture toughness K_mat = 50 MPa.m^0.5 at room temperature T0=20 oC. Under a...
  3. A

    Can mammals be cleared and stained?

    On the internet, I've only seen examples of fish and some amphibians being cleared and stained. If mammals can be cleared and stained, what is the difference in procedure?
  4. 1

    Deriving the magnetic moment of a specimen in a given magnetic field

    Homework Statement I'm working on a problem that says that >If $\varepsilon_{\pm}=\mp (\mu \mu_0 H + k \theta \frac{M}{\mu N} )$ is the energy of the atom of a specimen that can orient itself either parallel or antiparallel in a magnetic field, show that $ \frac{M}{\mu N}= tanh(\frac{1}{kT}(...
  5. ichabodgrant

    Size of specimen and compressive strength of concrete

    Hello everyone. I have a question about compressive strength of concrete. It is said that (in my country) 150 mm x 150 mm x 150 mm concrete cube is used for concrete testing. Someone asks me why 100 mm x 100 mm x 100 mm is not used. In fact, I know that sometimes it is allowed or even preferred...
  6. B

    Tensile Test Specimen Point of Failure

    I am a part C Mechanical Engineering student and have been undertaking a project investigating the strain sensitivity of a particular glass filled composite. From my quasi-static results, the stress-strain curves seem to be reasonable and match that of the mechanical material properties...
  7. 1

    The strain of a dog-bone specimen

    Homework Statement A dog-bone specimen made by aluminum alloy is used for tensile testing by a force of 4000N via two steel pins. The dimension of the specimen is shown in the following picture; the thickness of specimen and the length of pins are 4mm and 8mm, respectively. The mechanical...
  8. D

    Determine freq of AC that induces stress in the specimen

    Homework Statement An electromagnetic fatigue-testing machine has an alternating force is applied to the specimen by passing an alternating current of frequency ##f## through the armature. If the weight of the armature is ##40## lb, the stiffness of the spring ##k_1## is ##10217.0296## lb/in...
  9. B

    Flexural Modulus of a Test Specimen (3-point bending)

    Hello everyone, I need to work out the flexural modulus (Ef) of a test specimen that is subjected to a 3-point bend test. I know that: Ef = L3m/4bd3. I have: Support Span(L)= 0.1m width(b)= 0.01m depth(d) = 0.01m Max normal stress σf= 98.1 MPa Strain (εf) = 0.0525 Max force (applied...
  10. 1

    Radius of Specimen from Flexural Strength

    Homework Statement A circular specimen of glass is loaded using the three-point bending method. Compute the minimum possible radius of the specimen without fracture, given that the applied load is 4000 N the flexural strength is 65 MPa, and the separation between load points is 35mm...
  11. S

    Stiffness of specimen under tension

    Hello, I am conducting FE modelling on specimen of steel surrounded by concrete, and i obtain curve which have stiffness similar to experiment(all assume linear behaviour for all materials) but the start of curve is not convenient displacement -0.0071033 0.0123265 0.0310888...
  12. M

    Young's Modulus of a single crystal specimen?

    Does a single crystal specimen have a smaller Young's Modulus than a polycrystalline specimen? I think a single crystal would have a lower elastic mudolus since it has less grain boundaries and probably less dislocations than a polycrystalline specimen. I'd appreciate any ideas thanks
  13. T

    How do I calculate the illuminated spot on specimen in optical microscope?

    Hi, When we use an optical microscope, how do we roughly calculate the illuminated spot size on the sample ? Also what is the light power on that spot? And what if I change to fluorescence microscope(epi illumination)? Cause the illuminating light go through the rear side of objective to...
  14. J

    How is 100 W produced over 24 hours in Edexcel Unit 4 Specimen Paper?

    Homework Statement Please can someone look at the attached question (I have extracted MS and relevant previous pieces of information) Where do they get the idea that 100 W is produced over 24 hours ?? Homework Equations The Attempt at a SolutionI know power = work done / time but if power...
  15. J

    Electric field - multiple choice - Physics Unit 4 Specimen

    Homework Statement see attached file Homework Equations The Attempt at a Solution ok so I get that the answer is B but is it because they have the same q/m ratio?
  16. B

    Radioactvity - Specimen CCEA papers

    Homework Statement - 3c(i) A radioactive source is known to emit two types of radation. To find out which types, the apparatus shown below was set up. Three different materials were, in turn, places between the source and the detector. Here it shows source, absorber, detector and...
  17. J

    Physics Edexcel Specimen question

    Homework Statement http://www.edexcel.com/migrationdocuments/GCE%20New%20GCE/sam-gce-physics.pdf Unit 4 Q18) "A do-it-yourself..." could someone please explain to me ci) and cii) Homework Equations I cannot think of any equation to help meThe Attempt at a Solution I looked at the...
  18. T

    Help with curved specimen and mechanical loading.

    Background: Rib fractures in infants are highly suggestive of child abuse. I am performing mechanical testing and finite element analysis on pig ribs with the aim of characterising the behaviour of ribs under anterior-posterior (from end to end rather from the side) loading. Help needed: I...
  19. B

    Erosion Corrosion of Titanium Specimen

    Homework Statement Seawater at 13m/s containing 1750mg/L sand impinges on a 8cm^{}2 titanium specimen. I'm given a polarisation curve (which I'm unable to reproduce here for the moment) and the data that without cathodic protection a weight loss of 4.0mg is measured in 16 hours and with CP...
  20. H

    How large is specimen under microscope?

    Hello, I thought I help my nice with her microscope. We want to know how large some plant cells are that we're looking at. Hoe do we do that? There is no scale inside the microscope so I wonder if it possible to work out how large the field of view is with a certain lense. What do we have...
  21. S

    Carbon Dating: Calculating the Age of a Specimen

    1. An archeological specimen containing 8.7 g of carbon has an activity of 1.6 Bq. How old (in years) is the specimen? 2. Decay constant for Carbon= 0.693 / 5730 yr = 1.21 x 10^-4 1.6/8.7= 0.1839 activity per gram of C 0.23 is Activity of C at t=0 3. ln(0.1839/.23) =...
  22. L

    Are there any places that will pay you to become a lab rat?

    I want to know about having tests done on you. Are there any places that will pay you to become a labrat? Enough that you can live off of it and make a career out of it.
  23. G

    Notched specimen and brittleness

    How would you explain the fact that a notched specimen* of a ductile metal becomes brittle when tested uniaxially? The notch produces three axial tensions. But why does three axial tension cause brittleness? And how does the tension distribution look like in the notched area? Thanks...
Back
Top