Skylon – Sci-advent – Day 2


skylonThe image shows the flow of hot air passing through the piping in a cooler for a new engine that is able to lower the temperature of the air lower than -140C in just 1/100th of a second.

The cooler is part of a new type of spaceplane engine demonstrated bye Reaction Engines Ltd (REL), Oxfordshire. The company ran a series of tests on key elements of its Sabre propulsion system under the independent eye of the European Space Agency (Esa).

REL’s idea is for an 84m-long vehicle called Skylon that would do the job of a big rocket but operate like an airliner, taking off and landing at a conventional runway. The vehicle would burn a mixture of hydrogen and oxygen but in the low atmosphere the oxygen would be taken from the air, in the same way that a jet engine breathes air.

Taking its oxygen from the air in the initial flight phase would mean Skylon could fly lighter from the outset with a higher thrust-to-weight ratio, enabling it to make a single leap to orbit, rather than using and dumping propellant stages on the ascent – as is the case with current expendable rockets. A key element is the engine’s ability to manage the hot air entering its intakes at a high speed. These gases have to be cooled prior to being compressed and burnt with the onboard hydrogen.

REL’s solution is a module containing arrays of extremely fine piping that can extract the heat and plunge the inrushing air to about -140C in just 1/100th of a second. Ordinarily, the moisture in the air would be expected to freeze out rapidly, covering the piping in a blanket of frost and dislocating their operation.

It is the innovative helium cooling loop with its pre-cooler heat-exchanger that REL has been validating on an experimental rig.

Working Collaboratively Online: Wunderkit and Hojoki

Working collaboratively is nothing new… The challenge of continuing doing so with an ever-increasing use of online tools could definitely make life much easier. However, should you not be careful, you can quickly get a large number of new accounts in services that only a few people use.

You can tackle collaborative work using things such as email, but I am sure that you can agree with me that by the second iteration of doing and undoing tracked changes (once you have managed to convince other to track them that is…) becomes a bit tiring. In that respect, tools such as google docs have a distinctive advantage.

More recently I have come across a couple of new takes on the subject, one is Wunderkit and the other one is Hojoki. I started having a look at both of them, so this post is more about first impressions rather than fixed recommendations. Should you have any views on this, please do let me know.


This platform is brought to us by 6 Wunderkinder, a Berlin startup that also created Wunderlist (which is a good to-do application). Wunderkit lets you create projects that then can be shared with other people. The application lets you connect to Twitter and Facebook. Your contacts are treated in a similar way to followers in Twitter and you can invite contacts to your projects. You are supposed to be able to discover other people, but I must admit that the process was a bit cumbersome.

Once you have created a project and invited some people, your followers can post messages, comment on tasks, setup discussions and send status updates. A very interesting aspect of Wunderkit us that it includes some applications that can be very useful:

  • A progress tracker: You can easily see that is the status of the project and can easily see what peopler have been discussing as well as the activities that your collaborators have been working on.
  • A to-do list: The to-do list lets you set up tasks and lists. You can assign these tasks to specific members and setup due dates. I wish they could synchronise these lists with Wunderlist…. but never mind.
  • A notepad: This is a useful addition to the task lists ass you can add ideas, notes, scripts, etc, to your project.

Another useful thing about this application is the fact that not only does it live in the web, but the 6 Wunderkinder have created mobile applications that let you take your projects and lists with you. They also have a desktop application, but it seems that currently these additions are only for Apple devices. The accounts are free and should you need more support you can get a pro account. So far so good.


Tho other tool I wanted to talk about is Hojoki. Hojoki is also the creation of a German team and the prospect is a very interesting one. The main premise of the application is the accessibility, in a single place, of a number of existing outlets you already use: Dropbox, Google Docs, Github, Highrise, Mendeley, etc… Once you connect your different services, Hojoki creates a single feed that gets updated as soon as team members create actions such as saving or creating files, submitting updates, etc. It also integrated with Twitter, but should you be following a lot of people, this can be a bit too much! You can also setup workspaces and

It is a good idea and it exploits the cloud features of many applications. Currently it only works from a web browser although they say that a mobile app is a bit of a work in progress. Accounts are also free.

Well, all you have to do now is give them a go and let me know what you think. We might even be able to start a project using one of these tools.

SOPA blackout


Wikipedia is opposed to the US Stop Online Piracy Act aka SOPA and Protect Intellectual Property Act aka PIPA.
Other websites are also taking part in the blackout, such as Reddit and WordPress. For the full list of websites taking action against SOPA and PIPA today, check out the SOPA Strike website.

Mathematically inclined CAPTCHA

Early CAPTCHAs such as these, generated by the...
Image via Wikipedia

I’m sure you have encountered CAPTCHAS before. You might not know them with that name, but they have become a familiar feature of many websites. So, you want to book some tickets for a gig of your favourite band? Do you want to sign up to a new social network? Or simply interested in recovering your lost password? Well, you are more than likely to have used a CAPTCHA.

A CAPTCHA is a way to identify that the request to the services mentioned above (and many others) is not generated by a computer. This usually asking the user to complete a simple test for a human being but harder to replicate by a computer. One such task is character recognition. The text is supposed to be so distorted that a computer might have trouble identifying them, nonetheless a human being would be able to solve the problem in a very straightforward manner.

Recently this has been put to a good use with the use of reCAPTCHA, which is a service that helps digitise printed material. In many occasions the quality of some words is not good and therefore OCR (Optical Character Recognition) software struggles. However, many CAPTCHAS are solved by humans every single day and this is a resource that reCAPTCHA is chanelling. The idea is to send words that the computer is having problems identifying. So, if the computer cannot do it, how does the system know that you have given the correct answer???

Well, you are provided with two words one known and the other one is the word that needs resolving. If the answer for the known one is correct the system assumes that the second one is also correct. The key is that you don’t know which word is which. If many people are providing the same answer to that unknown word, then it is highly likely that it has been identified.

All of this is great, but what is the connection with the mathematically inclined CAPTCHA. Well, recently a friend of mine came across the following CAPTCHA. That is an excellent way to prove that you are not a bot, and that you are definitely a geek! Well done!

Maths Captcha


Technology of the past

PC DOS Command LineIt is amazing how much we take for granted when it comes to technology. I am still surprised that some youngsters do not know for example how to list the files in a folder using a command line, and cannot do much without a graphical interface.

This video is a great example of what how children try to make sense out of technology of the (not so remote) past. Enjoy!