Strain Definition and 462 Threads

In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are substantially smaller than the idealized value of approximately 109°. Because of their high strain, the heat of combustion for these small rings is elevated.Ring strain results from a combination of angle strain, conformational strain or Pitzer strain (torsional eclipsing interactions), and transannular strain, also known as van der Waals strain or Prelog strain. The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane.

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  1. Tsu

    News On Capitol Hill, Military Warns of Being under Strain

    http://www.latimes.com/news/nationworld/iraq/la-fg-troops18nov18,0,6045845,print.story Getting ready for the draft?
  2. C

    Find Radial & Circumferential Strain in Incompressible Vessel

    here's the question...the inner radius of a blood vessel with circular cylindrical cross section is distended during pressure elevation from radius a to a+∆a. assume the wall of the vessel is incompressible and the length of the vessel is constant. find the radial and circumferential...
  3. T

    Calculating Strain in a Slowing Elevator Cable

    A 1260kg freight elevator is supported by a steel cable of diameter 34.9mm. It is loaded with a crowd of people collectively having a mass of 2850kg and it is descending. What is the strain in the cable when it is brought to a stop in 0.600s? I'm not really sure how to figure in the fact...
  4. T

    Calculating Strain in a Steel Cable Supporting a Freight Elevator

    A 1260kg freight elevator is supported by a steel cable of diameter 34.9mm. It is loaded with a crowd of people collectively having a mass of 2850kg and it is descending. a) What is the strain on the cable while the elevator is descending at the constant speed of 2.30 m/s? b) What is the...
  5. T

    Help with Strain: Moving Elevator & Cable Stress Questions

    I'm having a real problem with this question, could someone please give me a hand? A 1260kg freight elevator is supported by a steel cable of diameter 34.9mm. It is loaded with a crowd of people collectively having a mass of 2850kg and it is descending. a) What is the strain on the cable...
  6. M

    LCD Monitors & Eye Strain: How Can I Reduce It?

    I have an LCD monitor for my computer and It seems to me that when up late a night and only having my monitor on no other lights it strains my eyes more. If I turn on a backround light would that help things, It seems to be less strain but I am not sure.
  7. E

    What Factors Influence the Design of a Strain Gauge?

    Hello. I am currently working on a project which requires me to deisgn a strain gauge. However, even though I have done quite a lot of research, I am still unable to find the answers to the questions that I have. They are: 1) How to decide the resistance (decided by the grid length as...
  8. J

    (-Planning Exercise - Strain gauge Coursework Help -)

    (--Planning Exercise - Strain gauge Coursework Help!--) Hi I've been stuck for several days in the early stages of my coursework i would have asked my tutor but I have been forced to stay home due to a very bad chest infection :frown: I will first provide a full transcript of the question...
  9. himanshu121

    Selling Eggs: Duck or Hen x2 for 1 Basket

    A salesman has 6 baskets containing eggs. There are 5,6,12,14,23,29 eggs in 6 baskets respectively. They are either ducks or Hens eggs. The salesman says if I sell one out of the six baskets containing eggs, then I would have chiken eggs twice the no. of duck eggs which basket was Salesman...
  10. $

    A very quick query about strain gauges

    I am doing a project on strain gauges. I have the thing set up in a half-wheatstone bridge. Using a pair of strain gauges I am trying to measure the weight!(attaching each one to a side of a ruler/cantilever and bending it by attaching weight to the end) So here's a confusing bit. I no when...
  11. K

    How does temperature affect the accuracy of a grandfather clock?

    A grandfather's clock is calibrated at a temperature of 20 degrees celcius. The pendulum is a thin brass rod with a heavy mass attached to the end. on a hot day, when the temperature is 30 degrees celcius does the clock 'run' fast or slow? how much time does it gain or lose in a 24 hour period...
  12. B

    Understanding Engineering Shear Strain: Formulas, Graphs, and Errors Explained

    Hello, I have problems with the "Engineering Shear Strain" formulas from the following website : http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/strain.cfm I agree with the formulas and the graph on the left, but I don't with it on the right. On the left graph du/dy and...
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