Friday, 24 April 2009

Engineering comes to life at Heathfield

On 10th March I went to Heathfield School for girls to give a presentation about my research area and encourage the girls to study engineering. It was as a part of Mini INSPIRE project. It gives post-doctoral researchers, PhD students and MSc students at Imperial College the opportunity to communicate the excitements of their research to young pupils. Mini Inspire is available to all postgraduates at Imperial College.
This was highlighted in the school news on their website www.heathfield.gdst.net:

Agnieszka’s presentation included information on her field of study, Tribology, which is the study of the effects of Friction, Wear and Lubricants in everyday life – in gears, bearings, rail wheels, in nature and the designing of artificial joints, in foods where the question of why low-fat foods do not taste as good is being investigated, in sport and the designing of the equipment used and in cosmetics where research is being done to improve the properties of make-up and hair conditioners. She also hosted a question and answer session. Pupils Melissa, Year 11 and Tharshiya, Year 12, both agreed that the talk had provided them with an insight to a field that they had both wanted to study at University. Melissa said “I thoroughly enjoyed the talk. It gave me an insight into engineering, particularly for women, as I am thinking of studying this at University.”

Tuesday, 30 September 2008

Tribology T-shirts

Ever wanted to have a tribology T-shirt? Check out my online shop by clicking the image above. I don't earn anything on that so the prices depend on the manufacturer only.
The shop is based in Germany and delivers all over Europe. Check delivery charges for your country. Currency is Euro.
More designs to come. Let me know if you like the idea and/or have any comments.
Enjoy!

Monday, 29 September 2008

Tribology is surreal?


I found this video on YouTube while searching for tribology-connected clips. It was created by so called "TomorroVation Research Group- an independent organization of technology historians, who this past Thursday, has unveiled to the U.S. tax-paying public the recently declassified top secret inventions of a little known 1950s-60s U.S. scientific facility, the Los Argyle National Laboratory."

As this is obviously some kind of surreal artistic or marketing project, I have not much idea what purpose it is supposed to serve.

Anyway, would be nice to not be classified as peculiarities of science anymore, dear Tribologists. Let this clip be a warning.

Thursday, 25 September 2008

NBA tribology

In fall 2006 NBA started using basketballs made with synthetic material instead of leather. They made the switch because they wanted every basketball they use to feel and bounce the same. Not all leather balls are exactly alike in weight or how they bounce, but the synthetic balls are. However, some players complained right away that the new balls bounced differently and were actually harder to control than the leather ones. Dallas Mavericks owner, Mark Cuban, asked for help from the Department of Physics at the University of Texas in Arlington, Texas.

What was the result of research conducted? One of major reasons for the differences observed was frictional behaviour.

Research summary (fragment):

  1. The surface of the synthetic balls display a factor of two higher coefficient of static friction when both leather and synthetic balls are dry. This characteristic would make the synthetic balls easier to grip (stickier) than the leather balls, when dry.

  2. However, with a few drops of added moisture on the surface of each type of ball, the new synthetic balls have a coefficient of friction which is at least 30% smaller than similarly moistened leather balls. We have also measured the moisture absorption rate, which confirms that the synthetic ball absorbs moisture at a much slower rate, leaving more of the moisture on the surface. Therefore, when wet, the synthethic balls are much harder to grip and handle (slippery). By contrast, our measurements indicate that the grip of the leather ball improves after similar moistening.

Details of Measurements (fragment):

  1. The synthetic balls absorb water at a much slower rate, averaging 8.6 grams per minute. The conditioned leather balls will absorb water more rapidly, about 70 grams within a minute. After quasi-saturation at these water masses, the leather balls absorb water at a much slower rate than the synthetic balls, averaging 3.3 grams per minute.

  2. Initial friction tests show a much higher coefficient of friction for the synthetic ball when dry. The coefficient of friction between the surface of the synthetic ball and a silicon surface (medical literature shows silicon to have a friction coefficient similar to the human palm) is about 3.2, for our experimental setup. The friction coefficient is 1.69 for the leather ball, using the same procedure.

  3. Friction tests with liquids such as Visine (which has viscosity higher than water, similar to human tear drop, possibly closer to sweat) applied to the silicon (one drop per 2"x2" area) show that the coefficient of friction increases for the leather ball. After repeated application of drops, the coefficient increased gradually by at least 30% for the leather ball, thereby making it more "gripable". After quasi-saturation. adding drops reduced the coefficient by 20%, relative to a dry ball. However, for the synthetic ball, the coefficient of friction reduces immediately by 55% with the first drop of liquid. A larger reduction is seen with repeated application of liquid. In conclusion, the wet synthetic ball is significantly more slippery compared to wet leather balls.

In January, the NBA went back to using the traditional leather balls. They aren’t perfect, but for now, that’s just the way the ball bounces.

Fast Facts:

  • It takes the hide of one whole cow to make four leather basketballs.
  • Leather balls absorb moisture eight times faster than the synthetic ones.
  • Because it absorbs so much sweat, a leather ball may increase its weight by 10 percent during a game, but a synthetic ball remains the same.

Sources:

National Geographic Kids
The University of Texas at Arlington

Wednesday, 24 September 2008

Have you heard of tribology?

In my search for any non-professional descriptions of what is tribology I found a blog Word Imperfect. Their motto is 'Have fun with a new word each day. I'll choose a word. You make up a meaning.' Apparently 'tribology' can be quite a riddle for those who try to figure out what it is.
Imagine a world where people hear the word 'tribology' and think of friction, lubrication, etc. instantly. Right....
Enjoy.

Tuesday, 23 September 2008

Call for Experiments!

Dear Tribologists,

I am asking for your help! I am planning to produce a leaflet for school science teachers with simple tribology experiments that can be shown to children and/or teenagers to help them understand basic concepts of tribology. To do so I would need some ideas from fellow tribologists.

Such experiments should:

  • be possible to conduct using simple, commonly available materials,-can’t be dangerous,
  • should have a clear aim,
  • should be possible to explain in simple terms,
  • can be your original idea or found online/in a book/somewhere else- if so, please give reference.
If you have no idea where to start from, there are some ideas available online, e.g.

http://www.thinkingfountain.org/f/friction/friction.html. Have a look and see how they should be designed (for more examples, Google ‘friction children experiments’, for instance). Friction force as such is quite well covered already, I would be really happy to hear some ideas about lubrication regimes, wear mechanisms, contact mechanics issues, etc.

I also plan in some undefined future to design some experiments that could be used for a museum exhibition. If you have an idea which can’t be used for a simple home/school experiment but still might be used in an exhibition, I’d also be glad to hear it.

Please let me know if you are interested in helping out. Tribology needs you!

Monday, 22 September 2008

Tribology is cool!

Tribology is the science and technology of interacting surfaces in relative motion. Its basic concepts such as wear, friction and lubrication are in general recognized, but the term „tribology” itself much less. It’s exotic to many and some tribologists seem to like it this way.

Science is cool, so is tribology. Let's share this knowledge with general public and children. Let's go out to schools, science museums and exhibitions, popular science literature and internet and show how fascinating it can be.

Tribology is everywhere. Not only in machines, vehicles, bearings, lubricants and train wheels. When you slip on the ice, light a match or slide in the water park, it's friction that you are experiencing... or missing. Your shoes or car tyres have worn out? Due to tribological processes. You don't like the texture of the fat-free yoghurt? Hey, that's tribology! In sports and cosmetics, inside your body and in the natural world. It's everywhere. Just look around.

Communicating with business, industry, university students, researchers from outside tribology and other tribologists- it's all very important. But we shouldn't forget- our responsibility as scientists is also education, especially to those who won't understand complicated formulas and jargon.

Let's share tribology.

This blog will try to show that tribology is important and cool. Wanna help?

A poster presented on Marie Curie Conference (Barcelona, 17-18 July 2008), satellite event of European Science Open Forum 2008.