The main criteria of failure:

Tresca (The Maximum Shear Stress)
Von Mises (Shear Strain Energy)

These are used for ductile materials but for brittle materials;

Maximum Principal Stress (Rankine)
Mohr Fracture Criterion
are used.

(Reference: `Mechanics of Engineering Materials` by P.P. Benham andR.J. Crawford provide a good introduction.)

Whitechapel Bell Foundry is Britain`s oldest manufacturing company. The company produced the Liberty Bell for the Philadelphia State House in 1752 and produced a replica of the Liberty Bell in 2001. A Bicentennial bell was also produced in 1976.
The Whitechapel business has been operating since 1570 and has produced some of the most famous bells in the world. Last year the firm cast in it`s foundry a new peal of twelve bells for the church of St Magnus the Martyr at London Bridge and if you are interested in this special company then look at the website www.whitechapelbellfoundry.co.uk

Recycling! Can we do better?

My workplace decided to start a collection of plastic bottles, cans and paper in order to recycle this waste. A very good idea however I get the feeling that this enthusiasm to recycle does stop people thinking of other possibilities. Reuse of products is a preferable option that doesn`t require a huge infrastructure to make it work. the waste hierarchy looks like this:
Re-use
Recycle
Dispose

Recycling is often the best solution but if we take a moment to ask is a product`s life can be increased by re-use then perhaps we can do better.

Bernoulli`s Equation

In Fluid Mechanics the energy equation is called Bernoulli`s but it is similar to the equation used in Thermodynamics. There are differences in Fluids when compared to Thermodynamics, Potential energy is important in fluids as is Kinetic energy.

1) What other energies are important in the Bernoulli equation?

2) State the equation when the units are:
(i) metres (ii) J/kg (iii) J

3) State the mass continuity equation.

Thermofluids The Gas Laws

The combination Gas law of pV/T = C can be used to solve most problems because it combines Boyle`s, Charles` and the pressure law. It`s normally used in the form p1V1/T1=p2V2/T2.

A variation is one where the Characteristic Gas Constant `R` is used. For example, R for AIR is 0.287 kJ/kg K.

Question: What are the units for each component of the pV=mRT equation?

The combined Gas Law allows us to do all calculations.

(p1V1)/ T1 = (p2V2)/T2

and pV =mRT where R is the characteristic gas constant.

For AIR, R= 0.287 kJ/kg K

Question: What are the units for all the components of the pV = mRT equation?
Also, prove the units for R = kJ/kg K.

The combined Gas Law allows us to do all calculations.

(p1V1)/ T1 = (p2V2)/T2

and pV =mRT where R is the characteristic gas constant.

For AIR, R= 0.287 kJ/kg K

Question: What are the units for all the components of the pV = mRT equation?
Also, prove the units for R = kJ/kg K.

KEVLAR is a modern material with many applications, particularly in the aerospace industry but an interesting fact about it is that is was invented by a woman.

1) What is the history of this material?

2) Find examples of successful applications of Kevlar.

3) State the important properties of Kevlar.

4) What is the origin of the name?

5) In which of the materials groups does Kevlar belong and how is it bonded?

In Jesi

The Palio di San Floriano

29th and 30th April 2006 and 4th, 5th, 6th and 7th May 2006.

Look at www.paliodisanfloriano.com for the programme.

The Corteo Storico through the town begins at 16.30 on Sunday, 7th May.
Let`s hope for good weather.