• ## Bainite

It's not pearlite or martensite. A blog written by Mathew Peet.

## Kinetic energy recovery for buses

Anyone who has watched formula one racing and experience a bus journey will appreciate the similarities, as buses repeatedly accelerate and decelerate for bus stops and junctions in the same way as the formula one car is repeatedly changing acceleration to allow it to be steered around corners.

A kinetic energy recovery system (KERS) usually stores energy during breaking in a device such as a flywheel, battery or capacitor.

Torotrak has recognised this too, and sees a good fit between capability of their kinetic energy recovery system and the service of London buses.

http://www.gizmag.com/torotrak-mechanical-kers-system-for-buses/13023/

I think this presents a good opportunity to remove pollution caused by stresses on engines as they try to move off from a stop. Just look at any place where a bus regularly stops (like rising bollards, junctions) and you will see how the smoke has built up on the road and surrounding street furniture.

Suppliers of kinetic energy recovery systems will emphasise the devices can often be retrofitted onto existing vehicles. However I think they could also enable vehicles to achieve the same accelerations or torques with lower powered engines. Heavy vehicles like a bus could be redesigned with smaller engines, not normally able to accelerate from a stop, by storing power in the KERS system while the bus is not moving, rather than only during braking.

Just to try out latex in wordpress (only included since 2007!)…
$\mathrm{K.E.} = \frac{1}{2} m v^2$

(extensive use of latex in wordpress can be seen here)

## How much is 1 tonne of carbon dioxide

I have a problem visualising 1 tonne of carbon dioxide. Firstly it is colourless, secondly it is usually a gas. So what sort of volume are we talking about?

Relative Molecular weight = 12 + 16 + 16 = 32 + 12 = 44 g / mol.
1 tonne of CO2 = 1000 × 1000 / 44 = 22727.27 moles

One mole of an ideal gas at STP occupies 22.4 litres (US liters).
Assuming CO2 is an ideal gas, approximate volume of 1 tonne of CO2 is 509090.9 litres = 5.1 ML (Megalitre).
5.1 ML = 5.09×106 × 0.001 = 509 m3

An olympic swimming pool is 50 m × 25 m × 2 m (minimum depth) = 2500 m3, so it would take 5 tonnes of gaseous CO2 to fill one.

## Steelmakers to challenge EU over emmissions

The FT is reporting that Steelmakers back challenge to EU rules (Peter Marsh) ArcelorMittal, ThyssenKrupp and Tata Steel are throwing their weight behind action by trade body Eurofer. Head of Eurofer and CEO of Voestalpine said that the way the EU commission has interpreted rules around carbon dioxide trading will give an unfair advantage to steelmakers in other regions.

According to Eurofer’s the commission’s interpretation of the regulations threaten to push the benchmarks for steelmaking too high. They say correct interpretation of the rules would result in an increase of 7 Euro/tonne of steel, and that the commissions interpretation will result in a cost of 12 Euro/tonne. This compares with the stated operating profit of 50 Euro/tonne.

12 Euro/tonne is equivalent to 1.4bn Euros (1.24bn UK pounds) and might be difficult to pass on to customers such as in the car industry. Figures above suggest a total profit of 5.83bn Euros (5.2bn pounds, 8.4bn US dollars, 55bn Chinese Yuan) for steel production in the EU, and a total steel production of 117 Mt.

## Boeing 787 Dreamliner Launch

The Boeing Dreamliner was launched for the first test flight yesterday.

The Boeing 787 is around the same size as 767-300. However the 787 is planned to be 20% more fuel-efficient than the 767. The efficiency comes equally from improvements in the engines, aerodynamics and reduced weight by use of composite materials, and the use of improved systems.

20% improvement in efficiency should translate into a 15% saving in operational efficiency.

Each plane can interchangeably use either the General Electric GEnx or Rolls-Royce Trent 1000, due to the design of a common interface. The Rolls-Royce engine was used for the test-flight.

## Saving Energy

Energy Reduction

If we all make a small saving it will make a large difference.

No, that will make a small difference

Small changes could only make large changes is we thought that Chaos theory could be applied. In that case “making a small saving may make a large difference” could have been used.

For a more rational assessment of energy policy you can look at David MacKays book, in which he uses numbers to examine the problems of supplying sustainable energy to the UK. The book can be found online at http://www.withouthotair.com/.

One way to save a little energy may be to use LED lighting as developed by Prof. Colin Humphreys. Which you can read about in the EPSRC press release
Low–Cost LEDs to Slash Household Electric Bills
. This can save energy in cases where household heating is supplied by Gas, or perhaps by heat exchangers (tungsten filament light bulbs also provide heating which may or may not be regarded as wasteful).