Archives for July 2005

Here is another cool idea that I’d like to try out. It has to do with an Israeli inventor who has developed a system that may allow people to breathe underwater without tanks.

“There are a number of limitations to the existing compressed air tank underwater breathing method. The first is the amount of time a diver can stay underwater, which is the result of the tank capacity. Another limitation is the dependence on oxygen refueling facilities near the diving site which are costly to operate and are used to compress the gas into the tanks which might be dangerous if not handled properly.

The final problem has to do with the actual use of air tanks underwater. When these tanks are in use they empty out and change the balance of the diver in the water.

Engineers have tried to overcome these limitations for many years now. Nuclear submarines and the international space station use systems that generate Oxygen from water by performing ‘Electrolysis’, which is electrical separation of hydrogen and oxygen from water. These systems require very large amounts of energy to operate. For this reason, smaller, diesel fueled submarines cannot use these systems and are required to resurface to re-supply their airtanks every so often. Divers can’t even consider carrying such large machines not to mention supplying them with energy.

To overcome this limitation an Israeli inventor, Alon Bodner, turned to fish. Fish do not perform chemical separation of oxygen from water; instead they use the dissolved air that exists in the water in order to breathe. In the ocean the wind, waves and underwater currents help spread small amounts of air inside the water.

Studies have shown that in a depth of 200m below the sea there is still about 1.5% of dissolved air. This might not sound like much but it is enough to allow both small and large fish to breathe comfortably underwater.

Bodner’s idea was to create an artificial system that will mimic the way fish use the air in the water thus allowing both smaller submarines and divers to get rid of the large, cumbersome air tanks.

The system developed by Bodner uses a well known physical law called the “Henry Law” which describes gas absorption in liquids. This law states that the amount of gas that can be dissolved in a liquid body is proportional to the pressure on the liquid body.

The law works in both directions – lowering the pressure will release more gas out of the liquid. This is done by a centrifuge which rotates rapidly thus creating under pressure inside a small sealed chamber containing sea water. The system will be powered by rechargeable batteries. Calculations showed that a one kilo Lithium battery can provide a diver with about one hour of diving time.”“

I found this story in the New York Times to be very interesting. I won’t post it in its entirety but will include a couple of excerpts.

High Tech in the 70’s, Shuttles Feel Their Age

“Until just a few years ago, some of the computers used in testing the shuttle’s boosters still contained Intel 8086 microprocessors, which are from the family that powered the first I.B.M. personal computers in the early 1980’s. That microprocessor has 29,000 transistors and operates at a speed of 10 million cycles per second. Today’s microprocessors tend to have 55 million transistors and run at a speed of 3.4 billion cycles per second.

The sensor system is far from the only shuttle component with potential problems.

Age-related complaints abound. Workers have sweated over the shuttle’s main engines, which endure some of the most pronounced stress of any component. Documents for the Discovery’s flight readiness review in June showed that engineers had found and dealt with tiny cracks along seals in the main engines and ruptures in some of the engines’ nozzle tubes.

In the solid rocket boosters, corroded bolts have been discovered in the motors’ nozzle joints. Elsewhere, a leak was discovered in a flexible hose used to deliver oxygen to the crew before the launching of the shuttle Endeavour in 2002; corrosion was later found in similar hoses.”

You wouldn’t think that the shuttle would be better equipped, but the article does show some reasons why they might be like this.

“And while the shuttle undergoes the kind of stresses that no conventional aircraft endures – the bone-rattling launching, the extreme cold of orbit and the fiery re-entry – Mr. Readdy, a former astronaut and pilot, said the high-stress periods were relatively brief for the shuttles, which might fly just dozens of times. By comparison, the average fighter jet undergoes far more wear and tear over its lifetime, he said.

NASA and others involved in the space program also note that older technologies, like the transistors hand-soldered onto circuit boards in the controller box for the fuel level sensors, may be more reliable than the delicate microprocessors found on newer craft.

“Sometimes high-tech doesn’t go with robust,” said Jeffrey Carr, a spokesman for United Space Alliance, the main contractor for the space shuttle.”

Ok, I lied, you have received most of the article, but it is just so interesting to me.

“The space agency has regularly upgraded aspects of the shuttles as well, as when it replaced the instrument panels and dials in the cockpits with modern flat-panel displays. Still, examples of the problems of an aging shuttle come up frequently. Just last week, the agency’s inspector general issued a report describing continuing problems with a kind of wiring used throughout the shuttles as a “safety risk.”

The document, which was first reported on nasawatch.com., said the wires were coated with an insulator known as Kapton that tended to break down over time, causing short circuits and, potentially, fires.

In a 1999 flight of the Columbia, a short circuit occurred five seconds after liftoff and caused two of the six computers that control the shuttle’s main engines to shut down.

NASA grounded the shuttle fleet for five months, and inspected and repaired some 1,300 problems it found with Kapton wiring on the Columbia alone. Many areas of wire that were inaccessible were not checked, and the accident investigation board recommended that the agency “develop a state-of-the-art means to inspect all orbiter wiring, including that which is inaccessible.”

But the agency has quietly dropped plans to comply fully with the recommendation to develop new nondestructive testing technologies, largely because of the Bush administration’s decision to retire the shuttle fleet by 2010.

The report assumed that the shuttles would be flying until 2020, as NASA had previously stated. The agency said the new system could not be ready before 2009 and would cost too much.

The inspector general’s report said that because no good alternative to Kapton had been found, any next-generation vehicle might also use it, and so the testing method would not be wasted. The report concluded that NASA was not following its own rules for managing risks.

Mr. Readdy said that the new procedures for inspection and documentation of all work done on the vehicles has greatly reduced the risk from Kapton wiring, and that even inaccessible wiring could be tested indirectly by monitoring either end of the inaccessible areas.

Dr. Griffin has compared the shuttle to a clipper ship, which he referred to as an amazing technological achievement now past its time. Of the shuttle, he said in a news conference this month, “I am in awe of the brilliant engineering that has gone into developing it maintaining it and sustaining it.” But, he added, “It’s time to move on.”

From a cave located somewhere on the East Coast DovBear has launched a rant about the decision to allow the NYPD to conduct random searches of the people who wish to ride the subway. Paul and Miriam have also issued their own responses to DB. You can find them here and here.

Let me preface this by saying that I do not like this at all. I agree that we are dancing on raindrops here and that there is potential for abuse but let us take a look at what the plan calls for:

NEW YORK (AP) — Police will begin random searches of bags and packages carried by people entering city subways, officials announced Thursday after a new series of bomb attacks in London.

Passengers carrying bags will be selected at random before they pass through turnstiles, and those who refuse the police request won’t be allowed to ride, Police Commissioner Raymond Kelly said.

He said officers posted at subway entrances would not engage in racial profiling, and that passengers are free to “turn around and leave.”

Within the comments thread DB boils down his concern with these words:

Ok, so let’s break it down:

1) Is being searched a viloation of your right to privacy?

No. But (a) it has to be truly random, and there is no such thing and (b) it opens the door to other intrusions.
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2) Do ramdom searches increase oue security in amy meaningful way?

No. Especially if you’re premitting people to decline the searches and try again in another station.
DovBear | 07.25.05 – 10:29 am | #

There is no doubt that are some civil liberties that are tied into this. One of my biggest concerns about the war on terror is what kind of balance we are going to be able to strike between protecting ourselves and the need to do so by eroding some of the freedom we take for granted.

It is not an easy thing to do and not something that should be allowed without careful thought. But careful thought also requires a mandate to look at ways that we can deter and prevent acts of terror. It is clear that without establishing additional security measures it would be really easy for a terrorist to do this kind of thing over and over. It would be negligent not to come up with something and I happen to think that random searches are a decent measure.

If people are willing to blow themselves up you have to expect that at some point in time someone is going to get around the measures and pull the trigger. I don’t expect it to be fullproof but I do expect that it could have benefits.

Part of fighting terrorism is establishing deterrents and preventative measures.

It is almost four years since 9/11 and we haven’t seen a succcessful attack within the US. I have to believe that the terrorists have tried and that they have been stopped from succeeding. But you don’t read stories like that. You only read about how the current admin is responsible for all of the ills within the world.

The sad reality is that the world is not the same place it used to be and if we do not take steps we will be punished for not doing so. And the truth of the matter is that is not impossible now for a cop to stop you on the street. You can scream about a lack of probable cause and fight it after the fact if you think that it was unfair.

But in the end I think that we are going to face a hard compromise with giving law enforcement some more tools to work with.