Category Archives: Politics and science

Today is the 115th anniversary of the discovery of X-rays

X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have awavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3 × 1016 Hz to 3 × 1019 Hz) and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma rays. In many languages, X-radiation is called Röntgen radiation, after Wilhelm Conrad Röntgen, who is generally credited as their discoverer, and who had named them X-rays to signify an unknown type of radiation.[1]:1–2 Correct spelling of X-ray(s) in the English language includes the variants x-ray(s) and X ray(s).[2] XRAY is used as the phonetic pronunciation for the letter x.[3]

 

X-rays from about 0.12 to 12 keV (10 to 0.10 nm wavelength) are classified as “soft” X-rays, and from about 12 to 120 keV (0.10 to 0.01 nm wavelength) as “hard” X-rays, due to their penetrating abilities.

Hard X-rays can penetrate solid objects, and their most common use is to take images of the inside of objects in diagnostic radiography and crystallography. As a result, the term X-ray ismetonymically used to refer to a radiographic image produced using this method, in addition to the method itself. By contrast, soft X-rays can hardly be said to penetrate matter at all; for instance, the attenuation length of 600 eV (~ 2 nm) x-rays in water is less than 1 micrometer.[4] X-rays are a form of ionizing radiation, and exposure to them can be a health hazard.

The distinction between X-rays and gamma rays has changed in recent decades. Originally, the electromagnetic radiation emitted by X-ray tubes had a longer wavelength than the radiation emitted by radioactive nuclei (gamma rays).[5] Older literature distinguished between X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m, defined as gamma rays.[6] However, as shorter wavelength continuous spectrum “X-ray” sources such as linear accelerators and longer wavelength “gamma ray” emitters were discovered, the wavelength bands largely overlapped. The two types of radiation are now usually distinguished by their origin: X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

(From Wikipedia’s article, X-rays)

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Ethanol won’t catch on in the US

I was just reading Carlos’s blog, and it says that the US will want to import their “alcool” (ethanol in English) fuel. I don’t believe we have such intentions. If we were to consume ethanol in mass quantities, it would be from corn growers, and through government subsidies before we rely on another country.

The U.S., potentially the largest market for the Brazilian ethanol, currently imposes trade restrictions on Brazilian ethanol in order to encourage domestic ethanol production, most of which has so far been based on processing corn instead of sugar cane or soybeans, which is much less efficient. There is concern that to allowing the heavily subsidized Brazilian ethanol to enter the U.S. market without taxation will undercut the budding ethanol industry in the United States (see a letter from six Democratic Senators to President Bush at http://harkin.senate.gov/news.cfm?id=255348 ). Others argue that rather than impose trade restrictions on the import of the Brazilian product, that the U.S. should make subsidies of its own available to support its fledgling domestic producers.

Well, I did a little research on this, and found out about ethanol in the US. I don’t know that it will really work in the near future. I lifted this off USA Today’s website, and I just wanted to quote some of the pertinent information here about why ethanol probably won’t catch on, at least for a number of years-

Why the USA might not embrace E85

Despite Brazil’s experience, don’t expect the USA to embrace E85 fuel, because:

You can’t find it. Where the ethanol is, people aren’t. Only 500 fuel stations sell E85 and most of those are in the lightly populated Midwest, which grows the corn to make the alcohol. The heavily populated coasts have only a few E85 outlets, and most are reserved for private fleets.

You’d probably have to buy a new car or truck to use it. The FFVs already out there are roughly 2% of all vehicles on the road, leaving Americans to replace the other 98% with new vehicles that have the corrosion-resistant fuel systems, special fuel injectors, sensors and computer controls, and hardened and coated engine parts necessary to survive alcohol’s corrosive onslaught and compensate for lower energy content.

You’d have to fill up more often. You’d be at the pump every four or five days instead of once a week. Ethanol contains about two-thirds as much energy as gasoline. The higher the concentration of alcohol in fuel, the more fuel you have to use to go the same distance. A vehicle would burn 1.4 times as much E85 as straight gasoline, the U.S. Department of Energy says.

A survey by luxury automaker Lexus found that the biggest reason people said they’d consider a fuel-saving Lexus hybrid vehicle was that its improved mileage meant fewer stops at the filling station. Environmental benefits and reducing petroleum use were secondary. E85 vehicles could have a big marketing challenge against that kind of attitude.

Your vehicle wouldn’t make the most of the fuel. FFVs are able to burn E85 but are tuned for best performance on gasoline because it’s abundant and E85 isn’t. An engine would have to be designed from scratch to fully exploit E85’s higher octane and overcome its inferior energy content.

“If you were using 100% E85, you could tune the engine and … maybe get 2% more power,” says Ken Kridner, the GM engineer who helped adapt GM V-6s to E85 capability. The Energy Department is more optimistic, suggesting gains of 3% to 5%.

Despite the barriers, the ethanol and auto industries are keen on E85’s promise. “E85 is going to be a much more significant market for us down the road,” RFA’s Dinneen says. “But you have to get more vehicles on the road that can use E85, and you need more outlets.”

“E85 holds great promise for fuel diversity, but we need to move from hundreds of fuel stations to thousands,” says Curt Magleby, manager of public policy for Ford Motor. Ford and ethanol producer VeraSun are offering to help pay the $3,000 to $5,000 it would cost a fuel-station owner, in the simplest case, to convert a gasoline pump to one that dispenses E85. Even so, a station owner might have to fight his gasoline supplier.

Some major oil companies refuse to allow alternative-fuel pumps near the regular gasoline pumps, if they allow them at all. The oil companies don’t have control over the quality and consistency of E85 so don’t want it sold under the big service station canopies that carry the oil company brand names and logos, they say.

“Alternatives to gasoline can succeed,” the California Energy Commission says in an analysis of ethanol and other non-petroleum fuels. “Unfortunately, a chicken-and-egg situation exists. Public acceptance and a healthy level of consumer demand are needed to make alternative-fuel vehicles viable, but a network of refueling facilities must also be in place. Oil companies are reluctant to build such facilities when vehicles themselves are not abundant. It is difficult to compete with tens of thousands of gasoline pumps and tens of millions of gasoline vehicles.”