Archive for December, 2009

Wolfram Alpha

30/12/2009 Leave a comment

Wolfram Alpha Logo

Wolfram Alpha Logo

Wolfram Alpha is not a threat to Google, yet, but it certainly is an alternative way of accessing data on the Internet.  It is described as an ‘answer engine’.  It does not return a list of web pages, when it is queried with some keywords.  The days of using this technique are, in any case, numbered as the Semantic Web becomes a reality.

Wolfram Alpha responds to factual queries.  It uses as its source a range of structured data, from which the answer is computed.  Access to the system was granted to the public in May 2009, and in the same year Popular Science voted it as the greatest computer innovation of the year.  The key difference between it and Google, is that to a query Wolfram Alpha returns a single definitive answer (if it can), rather than references to hundreds of thousands of web pages which may contain what you are looking for.

The system has been written in five million lines of Mathematica code, and is run across ten thousand CPUs.  It runs using the more recent versions  of  internet browsers (older versions have some difficulty in displaying the text, especially symbols), and an iPhone app gives some of the mobile community access.

So what does it do?  After a few minutes of exploration it is surprising what it can do, even including elements in the response which may be relevant to your query.  For example, if you ask “What is the GDP of Sri Lanka?” it will provide the answer together with other data which is deemed as appropriate, such as the unemployment rate, the current exchange rates with other currencies and a graph showing the GDP over the last thirty years.

It will respond to queries on a number of topics, click on the ‘Examples’ link on the home page, but to give you a flavour here is a small sample:

  • How old was Winston Churchill in 1955?
  • Try typing your first name, or the town where you were born
  • Enter any year
  • How far is Cape Town from Rome?
  • integrate sin x dx from x=0 to pi
  • time to fall 1000ft
  • house prices New York, Boston, San Francisco
  • weather London July 24, 1982
  • true airspeed p0=22inHg, 20000ft
  • life expectancy UK female age 21
  • skychart cambridge,uk
  • _al__la__
  • Ain’t No Sunshine
  • mortgage £150,000, 6.5%, 25 years
  • what is the meaning of everything?
Categories: Internet

Silicon Nanotubes – one-dimensional objects

27/12/2009 Leave a comment



The world of physics became very excited with the advent of silicon nanotubes (also known as nanowires) – describing them as wonderful, but what do we do with them?

Well, two uses are of real interest to us.  The first is the ability to turn waste heat in to energy and the second is a new generation of very efficient batteries. However, what is a one-dimensional object?  Well the prefix of the word Nanotubes tells you that these are microscopic objects. They are one-dimensional structures: that means that the nanotubes have length but no width or height from a physical standpoint. One-dimensional objects (like carbon nanotubes) are ideal for conducting heat or power because it is difficult to scatter or deflect whatever is being transported. It’s like a maglev train for molecules.

The Lawrence Berkeley National Labs is California estimate that some 55%-60% of all energy consumed in the USA is dissipated, much of it as waste heat.  The concept of converting heat to electricity is not new Approximately 90 per cent of the world’s power is generated by heat engines that use fossil fuel combustion as a heat source and typically operate at only 30–40 per cent efficiency, releasing roughly 15 terawatts of heat to the environment. If this “wasted heat” could be recycled at even the 5% level, the impact globally would be enormous.  The first attempts to produce nanotubes resulted in tubes with a ‘rough’ surface – initially disappointing researchers.  However, thermoelectric testing showed that rough nanowires allowed current to flow from a heat source toward a cold source but, astonishingly, the heat did not flow. By optimizing the roughness of the wires they were able to reduce the room temperature thermal conductivity by a factor of 100. While the physics behind the effect is not completely understood at this time, it maybe that thermal transport is impeded as heat waves simply bounce off the rough contours on the surface of the nanowires, but current flow is not impeded, as electrons are not similarly slowed down.  One can imagine recharging a mobile phone with electricity produced by the user’s body heat or reclaiming the heat that is released through a car’s exhaust system to power electronic devices.

The other area of excitement is in a new generation of batteries. The new technology produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop that now runs on a  battery for two hours could operate for 20 hours, a boon to all of us who love our mobile devices.  This has been described not as a small improvement, but a revolutionary development.  Material scientists are already very familiar with silicon, and therefore it should not be long (it is predicted within five years) that we see electric vehicles whose new silican nanotube-based batteries give them the kind of performance we have come to expect from their fossil-fuelled cousins.

Categories: Energy, Quantum Physics

Beam me up Scotty !

26/12/2009 Leave a comment



Apart from this being a mis-quote, ie no character ever said these words on Star Trek, these emotive words conjure a vision of ease of transport, or if you understand the principles, a fear of having your body destroyed by ripping all the atoms in a body and converting them to energy and then recreating a new version of the body in a different place.  One has also to consider that quantum mechanics, especially Heisenberg’s Uncertainty Principle, have a lot to say as to why it is not possible.  To overcome this the producers of Star Trek invented the ‘Heisenberg Uncertainty Compensator’ as a key component in their transporter.  One physics-savvy reporter was curious and asked a producer how the Heisenberg compensators worked, to which the reply was ‘they work very well, thank you’.

However, a giant leap (a quantum jump ?) has been taken in the development of quantum computers with some very excited about the possibility of a teleportation device becoming a reality as a result.   A team from the Joint Quantum Institute (JQI) at the University of Maryland (UMD) and the University of Michigan has succeeded in teleporting a quantum state directly from one atom to another over a substantial distance (1 metre).  The previous efforts have only succeeded over distances of micrometres.  Other attempts have transferred the quantum information of photons over very large distances.   The newest attempt has not actually moved matter over a distance, but provides a feasible means of holding and managing quantum information over long distances (the data stream in Star Trek).  The report claims that it works 90% of the time, so some way to go before 100% reliability is achieved.

Quantum teleportation depends on entanglement, one of the strangest of the many strange aspects of quantum mechanics. Two particles can become “entangled” into a single entity, and a change in one instantaneously changes the other even if it is far away.  This theory was well known by Einstein who described it as “spooky action at a distance”.  However, for the moment I think I’ll stick to Emirates Airline to transport me from one location to another distant one.

Categories: Quantum Physics, Transport

Space Elevators

26/12/2009 3 comments

Thanks to Jos Walker for suggesting this topic.  In 1895 the Eiffel Tower, a technological marvel of its time, inspired Konstantin Tsiolkovsky to ponder what would happen if it had been built tall enough to reach in to space.  He suggested a height of 35 790 kilometres, and that a ‘celestial castle’ be built at the top.  This castle, obviously, would constantly remain over the same spot on the surface – a geostationary orbit.  The idea was ahead of the materials science of the day, as no substance existed which would be able to support its own weight in such a massive structure.  In 1959, as the space race began, it was another Russian scientist, Yuri Artsutanov, who suggested a variation on the idea. His idea was to have a satellite which would lower a cable to the surface of the earth, whilst at the same time deploying a counter-weight on a cable in to a higher orbit.  He also proposed tapering the cable thickness so that the tension in the cable was constant—this gives a thin cable at ground level, thickening up towards geostationary orbit.

Space Elevator

Space Elevator

In 1965 four American physicists proposed a very similar idea in the journal Nature, but even then it was decided that no substance existed which would be strong enough to build the required cable of over 35 000 kilometres.   It was not until the development of carbon nanotubes in the 1990s that materials science was able to support the concept, which could become a reality in the 21st century.  It has been suggested that the establishment of a prize, along the lines of the Asari X-prize, may speed up development.  As recently as 2008 a book, titled “Leaving the Planet by Space Elevator”, was published in Japanese and became a best-seller in Japan.  As a result the Japanese government have committed to building a space-elevator at an estimated cost of some £5 billion. 

In a conventional elevator the car is raised by pulling on cables.  The space elevator would use a cable that would remain stationary, and the elevator would ‘climb’ up the cable.  Several power sources have been suggested, but the emerging favourite is to use a megawatt laser in conjunction with 10m wide mirrors at various heights on the cable.  If the counterwight was at a distance of 144 000 Km,then ‘firing’ a vessel from that distance would impart enough velocity to escape Earth’s gravitational pull.  The concept is very much in vogue, and Nasa are considering the viability of a space elevator, and even building one on Mars to aid the colonisation of the planet.

Categories: Space, Transport