Einstein proved in 1905 that a photon of light can activate metal oxide (photocatalytic oxidation or PCO). Studies in the US have shown the process can create toxic side-effects, yet a company in the Czech Republic says they have created a powerful air-cleansing paint for indoor use

In a small, rather dilapidated factory on the outskirts of Prague, a company called Advanced Materials is putting titanium dioxide to use in something called photocatalytic paint, an incredibly clever, virtually translucent paint that actually cleans the air in your living room of everything from bacteria to cigarette smoke.

“Even in a concentration of one cigarette per cubic metre, you see very high degradation rate,” said Jan Prochazka, Advanced Materials’ co-owner. In one hour, he said, a cubic meter box used to test the paint is clean of cigarette smoke.

“We say [the paint will oxidize] ninety percent of all contaminants in 24 hours, but it’s much faster. It’s just to stay on the safe side,” Prochazka added.

There are two risks to this kind of solution. First, the paint has to sit on a base that can resist it and second, the byproduct of the paint has to be non-toxic.

Air-Cleansing cement for outside use has been available for nearly ten years and paint was introduced five years ago.

In 2002, after 7000 square metres of road surface in Milan, Italy, were covered with a catalytic cement, residents reported that it was noticeably easier to breathe – with the concentration of nitrogen oxides at street level cut by up to 60 per cent. […] The paint could cover a much greater surface area than cement, since every building and piece of street furniture could be painted with it. Photocatalytic cements and paving slabs are already used in Japan, where the market for such building materials is growing.

These outdoor solutions have proven the first risk has been controlled. The second risk, however, is not settled. Science labs in the US report increases in formaldehyde and acetaldehyde. They propose air-ducts or standalone units be setup with PCO, instead of used as an indoor paint, so the flow of air is controlled and then filtered with “chemisorbent oxidizer—sodium permanganate—downstream of the PCO device”.

Small, stand-alone active PCO units are available commercially, but Destaillats warns buyers that the performance of current products is uncertain. It is possible that some units produce harmful aldehydes and that catalysts become deactivated.

Berkeley Lab’s current research addresses only the large systems that can be incorporated into a building’s HVAC system. These systems are still in the experimental phase. Ideally, in-duct air cleaners should include several stages (such as the use of a chemisorbent after the PCO), but the cost of a multi-stage system may be cost-prohibitive for some.

The BBC has an interesting look at how Columbia has changed to a safe and prosperous country. They call it “Colombian rebel comes in from the jungle”

You may have heard of [Medellin] as one of the most dangerous cities in the world, the former stronghold of the notorious drugs lord Pablo Escobar.

But Pablo Escobar was shot dead by police back in 1993, and that was when the tide of violence began to turn.

Today, Medellin is a very different place.

It is a bustling city, with a population of 2.5 million and it is now said to be one of the safest cities anywhere in Latin America.

Seventeen years is a whole new generation. With opportunities and even equality comes a good life in the city, which makes it hard for rebels and terrorists to recruit into a high risk and tough life in the mountains.

The problem with a jet that has no wings is that it has to be in contact with a rough surface. Even the flat, smooth lake bed for speed trials is extremely rough compared with debris in the air. Taking the Bloodhound car up to 1,000mph means the car will need impervious wheels

The 97kg aluminium discs that will act as its wheels will have to resist being blasted by a stream of grit thrown up from underneath the vehicle as it races across a dry lake bed at over 1,000mph.

Researchers are trying to identify the best alloy for the task.

This has resulted in them firing pieces of grit at samples of metal using a gas gun at Cambridge University.

Or they could attach wings, get a little lift to retract the main wheels and just use one little wheel dragging along to say it was still on the ground…

Symantec is calling recent help with their Stuxnet analysis, from a Dutch Profibus expert, a breakthrough

The new information confirmed that Stuxnet is looking for very specific types of industrial control systems to modify. More importantly it revealed that the code would very carefully check to see if it was on the right type of device and then alter speeds over an extended period by slightly changing output frequencies.

Once operation at those frequencies occurs for a period of time, Stuxnet then hijacks the PLC code and begins modifying the behavior of the frequency converter drives. In addition to other parameters, over a period of months, Stuxnet changes the output frequency for short periods of time to 1410Hz and then to 2Hz and then to 1064Hz. Modification of the output frequency essentially sabotages the automation system from operating properly. Other parameter changes may also cause unexpected effects.

This sounds very much like an attempt to cause quality control failures or even process disruption. Uranium enrichment is mentioned again. Given the effort to create Stuxnet the target would have to be something that would be seriously affected by minor changes over several months time.

I know nothing about uranium enrichment other than anecdotal bits from the Manhattan Project. Assuming the target actually was Iran, this does seem to fit the bill. Wikipedia describes a process most likely to be used in the Iranian plants as a long and very careful one.

The gas centrifugation process utilizes a unique design that allows gas to constantly flow in and out of the centrifuge. Unlike most centrifuges which rely on batch processing, the gas centrifuge utilizes continuous processing, allowing cascading, in which multiple identical processes occur in succession. The gas centrifuge consists of a cylindrical rotor, a casing, an electric motor, and three lines for material to travel.

Would the PLC changes introduced by Stuxnet be subtle enough to run without detection when such a system has to run with very low tolerance? Did someone know that the quality monitoring was so poor it would not pick up the changes, even over several months time? It sounds more and more like an inside job like the Maroochy Shire sewage control failure.

The Maroochydore District Court heard that 49-year-old Vitek Boden had conducted a series of electronic attacks on the Maroochy Shire sewage control system after a job application he had made was rejected by the area’s Council. At the time he was employed by the company that had installed the system. Boden made at least 46 attempts to take control of the sewage system during March and April 2000.

Utilities can not say they have been unaware of this threat type. Boden used remote access to modify controls but the more important point is that he knew where and how to make changes that would not be detected in time to prevent a failure.