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1 "Smogmobile" : a jovo autoja? (mind)  125 sor     (cikkei)
2 Gentechnologia (mind)  98 sor     (cikkei)

+ - "Smogmobile" : a jovo autoja? (mind) VÁLASZ  Feladó: (cikkei)


SEATTLE, Washington, August 7, 1997 (ENS) - The technology of alternative
fuel vehicles is leapfrogging quickly over electric cars, and it has left
conventional gasoline powered vehicles far behind in the dust. Liquid
nitrogen is the newest alternative fuel - used to power the "smogmobile."

When engineers at the University of Washington (UW) set out to create a
vehicle that is cleaner and safer to operate than gas or electric cars,
they jokingly named it the smogmobile after a L'il Abner cartoon depicting
a car fueled by air pollution. But the vehicle developed by the UW team
almost lives up to its name. Running on liquid nitrogen, the smogmobile
generates no harmful emissions and actually creates an opportunity for
pollutants to be removed from the air as its fuel is produced.

"If you're going to talk about a truly non-polluting car, you have to do
something different than gas or electric," explains Abe Hertzberg,
professor emeritus of aeronautics and astronautics at the UW and head of
the smogmobile project. "We believe a liquid nitrogen vehicle can match the
performance and range of an electric car, while still being affordable and
easy to maintain and operate. And ecologically, it's a dream come true."

Carl Knowlen, a UW research scientist working on the project, will present
a paper on the smogmobile at the Society of Automotive Engineers Future
Transportation & Technology conference and exposition today in San Diego.

The smogmobile is powered by energy from pressure built up when
super-cooled liquid nitrogen is heated by ambient air and converts to a
gas. The nitrogen gas turns an air motor, which propels the car, then exits
the tailpipe. Since the atmosphere already is 78 percent nitrogen, the
environmental effect of driving smogmobiles - even millions of them - would
be virtually undetectable, Hertzberg says.

What really excites this veteran researcher is the potential of liquid
nitrogen production to actually reduce air pollution. To make liquid
nitrogen, Hertzberg explains, a plant would simply run air through a large
refrigeration system and collect the liquid nitrogen as it condenses. In
the process, pollutants such as carbon dioxide also are removed from the
air and could be disposed of in a benign manner.

Hertzberg pursued the smogmobile project in part to pull the plug on the
electric car bandwagon being propelled by laws in California and elsewhere
that require 10 percent of all cars sold to be zero-emission vehicles.
Heralded as the most environmentally friendly alternative to smog-belching,
gas-powered vehicles, electric cars offer chronically poor performance and
present pollution and safety problems of their own, UW researchers contend.

Lead-acid batteries, which are used in General Motors' EV1 electric car,
have a limited 70 to 90-mile range and threaten to increase heavy-metal
pollution. Newer nickel-metal hydride and lithium-ion batteries offer
better range and performance, but they are prohibitively expensive and
potentially dangerous.

"The safe batteries are an ecological mess and can't go anywhere,"
Hertzberg explains. "The ones that can go anywhere are incredibly expensive
and quite dangerous. As the amount of stored energy increases in these
batteries, they become like bombs and could do a lot of damage in a traffic
accident. You'd have to work really hard to hurt yourself with a liquid
nitrogen vehicle. Liquid nitrogen isn't combustible, corrosive or toxic.
It's just cold."

Ironically, Hertzberg says, the cold temperature is precisely what stalled
previous efforts to develop a liquid nitrogen vehicle. Researchers have
known for decades that pressure built up when super-cooled liquid nitrogen
is converted to a gas could power a car. But the UW group was the first to
develop a heat exchanger system that prevents frost build-up from impeding
the conversion process.

The smogmobile's heat exchanger pulls liquid nitrogen from an insulated
fuel tank through a series of aluminum tubing coils and specially designed
pipes. Engine exhaust and outside air are circulated around the coils and
pipes to gradually warm up the nitrogen from a minus-320 F liquid to an
ambient-temperature gas. The conversion from liquid to gas expands the
volume of the nitrogen 700 times, building sufficient pressure to turn an
air motor much like pressure from burning gasoline drives an internal
combustion engine.

One major difference is that gasoline is a non-renewable resource so
internal combustion engines have become more efficient over the years. With
the abundance of air, there hasn't been the same motivation to make air
motors use compressed air more efficiently. The motor employed in the
smogmobile prototype was built to power a winch for raising ship anchors.
It has the high torque needed to propel a vehicle but consumes the
converted nitrogen gas fuel as if it, too, was as abundant as air.

"This motor operates at about 20 percent of the efficiency we think is
possible, so it greatly reduces the mileage we can achieve on a tank of
fuel," explains John Williams, a master's student in the department of
aeronautics and astronautics who has worked on the smogmobile project for
two years.

Under a $360,000 U.S. Department of Energy grant, Knowlen, Williams and
fellow students Peter Vitt and Helene DeParis have built a smogmobile
prototype from a converted mail truck. The prototype musters only a fifth
of a mile per gallon using the inefficient winch motor.

But Hertzberg is seeking a follow-on grant to design a more efficient motor
that could achieve two to three miles per gallon in an optimally designed
vehicle. This would enable the smogmobile, using a 100-gallon tank, to
match the average range for gas-powered vehicles of 250 miles between
fill-ups. As large as the 100-gallon tank sounds, Williams said it would
still weigh less than the batteries used in electric cars.

The liquid nitrogen vehicle also has the potential to be more economical to
operate than either electric or gas powered vehicles, according to the UW
researchers. Assuming an 8-cent-per-gallon price for mass produced liquid
nitrogen, they predict the smogmobile would cost 3.8 cents per mile to
drive. This compares favorably with the 6.2-cent-per-mile cost of operating
gas-powered vehicles and electric cars (including the cost of battery
replacement every two to three years).

Despite the environmental and economic benefits of liquid nitrogen
vehicles, Hertzberg realizes it will be difficult to attract the interest
of an automotive industry and public already committed to gas-and
electric-powered cars. But he hasn't let that stop him.

"I don't expect any trouble in proving that a liquid nitrogen vehicle can
work, I expect trouble in selling the idea," he said. "But this has become
a bit of a holy grail for me because it's the right thing to do. This is a
car that will work with the environment instead of against it."

The EnviroNews Service              | E-Mail: 
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+ - Gentechnologia (mind) VÁLASZ  Feladó: (cikkei)

Tisztelt KORNYESZ!

	A kovetkezokban megprobalkozom azzal, amire Diana 
nemregiben rakerdezett. Elsosroban Dananak a cikk vegen 
felsorolt problemaira probalok meg valaszolni.

>.  Akkor atadom Dananak
> a szot -- bevallom, engem elegge meggyozott.  Megprobalkozik valaki
> megcafolni vagy tompitani az erveit?

> 1. Food safety.  When I spray Bt on my potatoes, its poison gets made only
> within beetles.  It barely touches the potato leaves, and it quickly washes
> away.  The Monsanto potato has the toxin everywhere, even in the tubers we
> eat.
> We can't wash it out.  Everything we know says that toxin harms only beetles.
> But we don't know everything.

	A permetezoszerek (biologiaiak is) szinten behatolhatnak a 
novenybe es mergezok lehetnek. 
> 2. Pest resistance.  Whenever a pest comes in contact 
with a poison, it's
> possible that a few of its multiferous, fast-breeding number can survive.
> Those resistant pests are the ones that produce the next generation.  The
> more
> exposure, the faster the whole pest population will develop resistance.  The
> Colorado potato beetle is second only to the green peach aphid in its
> acquired
> resistance to hard-core pesticides.  But it is not yet resistant to Bt.
> Exposing the beetle to fields of potatoes carrying Bt toxin in every leaf
> during the whole growing season is just asking for widescale resistance.
> Monsanto's potato will destroy both itself and a good organic crop protection
> tool.

	Rezisztancia permetezoszereknel is kialakulhat (sot 
szerintem ott konnyebben, ugyanis ott a karokozok 
nehezebben szedik ossze a halalos dozist (nagyobb az eselye 
a tulelesnek.

> 3. Company goofs.  Monsanto revealed recently (and quietly) that another of
> its
> biotech products, a gene-spliced canola seed, had been mistakenly sold with
> the
> WRONG GENE in it, a gene that had not been tested or licensed.  The problem
> here is not that companies make mistakes -- of course they do.  The problem
> is
> that genetic engineering, like nuclear power, is not an arena where we want
> mistakes to be made.

	Valo igaz, hogy vigyazni kell a genetikaval, de megfelelo 
kontroll mellett eppoly veszetelen es biztonsagos, mint az 
atomenergia (bar nem hiszem hogy ezzel a megjegyzesemmel a 
vad kornyezetvedok egyetertenek).
> 4. Further consequences in nature.  We don't know what ecosystems will do
> with
> genetically altered species.  Will the ability to make beetle toxin suddenly
> show up in, say, wild nightshade, which is a relative of the potato?  (A
> gene-spliced cultivated mustard has recently been shown to transfer its
> bioengineered gene to wild mustards.)  Or could resistant beetles, no longer
> held in check by wild Bt, wipe out the whole nightshade family (which
> includes
> tomatoes and eggplants)?  The worst nightmare of genetic engineering is the
> gene that gets loose.  That isn't likely.  But it isn't impossible.

	A jovobeli kovetkezmenyek: ki tudja, hogy milyen 
kovetkezmenyei vannak annak, hogy valaki cikkeket irogat az 
Internetre. Lehet, hogy valamikor emiatt robban majd ki a 
harmadik vilaghaboru (lepkeszarny effektus).  Fogalmunk 
sincs, hogy akar mindennapi cselekedeteink milyen 
valtozast hoznak letre a termeszetben, de ennek ellenere 
csinaljuk a dolgainkat. Ha csak a negativ valtozasokra 
gondolunk, amiket eloidezhetunk, akkor legjobb ha mar ma 
ongyilkosok leszunk. Miert baj az, ha valtozik a vilag?
(Az  elszabadult gen pedig inkabb egy fantasztikus filmbe 
valo otlet).	

	Kivancsi vagyok, hogy a gentechnologia ellenzoi 
tiltakoznak-e vajon a keresztezesek (novenynemesites) ellen 
is. Mondjuk, amikor olyan fajtak kifejleszteserol van szo, 
amelyek jobban illeszkednek a biokerteszet igenyeihez.
	Ha nem akkor, nem ertem, hogy miert tiltakoznak a 
gentechnologia ellen. Vegul is mindket esetben a genetikai 
allomanyt manipulaljak csak az egyik esetben kromoszoma 
szinten, mig a masikban gen szinten. (Megjegyzem szerintem 
kromoszoma szinten a rendszer osszetettebb volta miatt meg 
nehezbb elore megjosolni az eredmenyt.)
	Az ember mar regota beavatkozott a "termeszetes 
kivalasztodasba" (lasd a tenyesztest). Most csinaljuk ezt 
	Van egy filozofiai termeszetu problemam is ezzel 
kapcsolatban: miert nem lehet az ember altal letrehozott 
valtozasokat is termeszetesnek tartani? Vegul is az ember 
is resze a termeszetnek, nem?

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