Scientists Discover Heavy New Element By
JAMES GLANZ
A team of Russian and American scientists
has discovered a new element that has long stood as a missing link among the
heaviest bits of atomic matter ever produced. The element, still nameless,
appears to point the way toward a brew of still more massive elements with
chemical properties no one can predict.
The team produced six atoms of the element
by smashing together isotopes of calcium and a radioactive element called
berkelium in a particle accelerator about 75 miles north of Moscow on the
Volga River, according to a paper that has been accepted for publication at
the journal Physical Review Letters.
Data collected by the team seem to support
what theorists have long suspected: that as newly created elements become
heavier and heavier they will eventually become much more stable and
longer-lived than the fleeting bits of artificially produced matter seen so
far.
If the trend continues toward a theorized
“island of stability” at higher masses, said Dawn A. Shaughnessy, a chemist at
Lawrence Livermore National Laboratory in California who is on the team, the
work could generate an array of strange new materials with as yet unimagined
scientific and practical uses.
By scientific custom, if the latest
discovery is confirmed elsewhere, the element will receive an official name
and take its place in the periodic table of the elements, the checkerboard
that begins with hydrogen, helium and lithium and hangs on the walls of
science classrooms and research labs the world over.
“For a chemist, it’s so fundamentally cool”
to fill a square in that table, said Dr. Shaughnessy, who was much less
forthcoming about what the element might eventually be called. A name based on
a laboratory or someone involved in the find is considered one of the highest
honors in science. Berkelium, for example, was first synthesized at the
University of California, Berkeley.
“We’ve never discussed names because it’s
sort of like bad karma,” she said. “It’s like talking about a no-hitter during
the no-hitter. We’ve never spoken of it aloud.”
Other researchers were equally circumspect,
even when invited to suggest a whimsical temporary moniker for the element.
“Naming elements is a serious question, in fact,” said Yuri Oganessian, a
nuclear physicist at the Joint Institute for Nuclear Research in Dubna,
Russia, and the lead author on the paper. “This takes years.”
Various aspects of the work were done at the
particle accelerator in Dubna; the Livermore lab; Oak Ridge National
Laboratory and Vanderbilt University in Tennessee; the University of Nevada,
Las Vegas; and the Research Institute of Atomic Reactors in Dimitrovgrad,
Russia.
For the moment, the discovery will be known
as ununseptium, a very unwhimsical Latinate placeholder that refers to the
element’s atomic number, 117.
“I think they have an excellent convincing
case for the first observation of element 117; most everything has fallen into
line very well,” said Walter D. Loveland, a professor of chemistry at Oregon
State University who was not involved in the work.
Elements are assigned an atomic number
according to the number of protons — comparatively heavy particles with a
positive electric charge — in their nuclei. Hydrogen has one proton, helium
has two, and uranium has 92, the most in any atom known to occur naturally.
Various numbers of charge-free neutrons add to the nuclear mass of atoms but
do not affect the atomic number.
As researchers have artificially created
heavier and heavier elements, those elements have had briefer and briefer
lifetimes — the time it takes for unstable elements to decay by processes like
spontaneous fission of the nucleus. Then, as the elements got still heavier,
the lifetimes started climbing again, said Joseph Hamilton, a physicist at
Vanderbilt who is on the team.
The reason may be that the elements are
approaching a theorized “island of stability” at still higher masses, where
the lifetimes could go from fractions of a second to days or even years, Dr.
Hamilton said.
In recent years, scientists have created
several new elements at the Dubna accelerator, called a cyclotron, by smacking
calcium into targets containing heavier radioactive elements that are rich in
neutrons — a technique developed by Dr. Oganessian.
Because calcium contains 20 protons, simple
math indicates scientists would have to fire the calcium at something with 97
protons — berkelium — to produce ununseptium, element 117.
Berkelium is mighty hard to come by, but a
research nuclear reactor at Oak Ridge produced about 20 milligrams of highly
purified berkelium and sent it to Russia, where the substance was bombarded
for five months late last year and early this year.
Fuel for deep space exploration running on empty
By SETH BORENSTEIN, AP Science Writer Seth Borenstein, Ap Science Writer
Thu May 7, 11:00 am ET
WASHINGTON – NASA is running out of nuclear fuel needed for its deep space exploration.
The end of the Cold War's nuclear weapons buildup means that the U.S. space agency does not have enough plutonium for future faraway space probes — except for a few missions already scheduled — according to a new study released Thursday by the National Academy of Sciences.
Deep space probes beyond Jupiter can't use solar power because they're too far from the sun. So they rely on a certain type of plutonium, plutonium-238. It powers these spacecraft with the heat of its natural decay. But plutonium-238 isn't found in nature; it's a byproduct of nuclear weaponry.
The United States stopped making it about 20 years ago and NASA has been relying on the Russians. But now the Russian supply is running dry because they stopped making it, too.
The Department of Energy announced on Thursday that it will restart its program to make plutonium-238. Spokeswoman Jen Stutsman said the agency has proposed $30 million in next year's budget for preliminary design and engineering. The National Academy's study shows why it is needed, she said.
"If you don't have this material, we're just not going to do" deep space missions, said Johns Hopkins University senior scientist Ralph McNutt, who has had experiments aboard several of NASA's deep space missions.
So far only NASA undertakes these missions, so the shortage limits the world's look at deep space, added Doug Allen, a satellite power expert and member of the National Academy's study panel.
By law, only the Department of Energy can make the plutonium. Last year then-NASA administrator Michael Griffin wrote to then-Energy Secretary Samuel Bodman saying the agency needed more plutonium.
The National Academy report says it would cost the Energy Department at least $150 million to resume making it for the 11 pounds a year that NASA needs for its space probes.
Without that material "a lot of things will be shut down and they will stay shut down for a long time," McNutt said.
Upcoming NASA missions using plutonium include the overbudget and delayed Mars Science Laboratory, set to launch in 2011, and a mission to tour the solar system's outer planets scheduled for launch in 2020.
The last two missions to use plutonium were the New Horizons probe headed for Pluto and the Cassini space probe that is circling Saturn. Plutonium-powered probes last a long time. The twin Voyager spacecraft headed beyond our solar system and launched in 1977 are expected to keep working until about 2020, McNutt said.
Solar power is preferable to plutonium because it is cheaper and has fewer safety concerns, McNutt and Allen said. But solar power just doesn't work in the darkest areas of space, including deep craters of the moon.
Some have protested past nuclear-powered missions, such as Cassini, worrying about potential accidents.
Some bright researchers say they've created the world's
smallest incandescent lamp,
so teeny it's invisible except when lit.
The lamp's filament is just 100 atoms wide. It is made from a
single carbon nanotube.
When lit, the
itty bitty bulb can be seen with the unaided eye as a point of light,
the scientists say.
Thomas Edison's light bulbs also used carbon filaments. But
the new filament, created at UCLA, is 100,000 times narrower and 10,000 times
shorter than those made by
Edison.
But why?
The breakthrough comes at a time when inventors are moving
away from incandescents, even looking beyond the green-leaning
compact fluorescent bulbs
(CFLs), and trying to figure out how to make
LED lights cheap
enough to take over the job of lighting homes and offices.
So why does this miniscule feat matter?
The filament is big enough to apply the
statistical assumptions
of thermodynamics, which are longstanding rules about how stuff works when
lots of particles are involved, the researchers explained. Yet it is also
small enough to be considered molecular, meaning the laws of
quantum mechanics -
involving very few particles - apply.
Big picture
In lay terms, the invention is aimed at helping the scientists
better understand how the physics of large things and the physics of invisible
things are, perhaps, related. Or, as they put it:
"Our goal is to understand how
Planck's law gets
modified at small length scales,"
said Chris Regan,
assistant professor of physics and astronomy at the university. "Because both
the topic (black-body radiation)
and the size scale (nano) are on the boundary between the two theories, we
think this is a very promising system to explore."
If no lights went on for you there, be comforted by the
thought that all this bears on the hoped-for "theory
of everything" that, if discovered, would help
explain gravity and
how the universe works and also probably put a lot of physicists out of work.
The work, funded by the
National Science Foundation,
is explained in the May 5 in the online edition of the journal
Physical Review Letters.
. Hydroxide in water forms an ionic compound with the
iron ions:
Fe3+(aq) + 3 OH-(aq)
Fe(OH)3(s) (Another form)
When iron hydroxide dry:
Fe(OH)2
→
FeO + H2O
Fe(OH)3
→
FeO(OH) + H2O
2 FeO(OH)
→
Fe2O3 + H2O
.
Rust: Fe2O3 (a dry powder)
Also, FeCl3 (s)
What is a "Galvanized Nail?"
A zinc coated surface--zinc metal will oxidize to ZnO--a rather transparent
coating. The term "sacrificial anion" is sometimes used to describe the
use of this thin coating.
ΔS = (-)
What’s Lurking in Your Countertop?
By KATE MURPHY
SHORTLY before Lynn Sugarman of Teaneck, N.J., bought her
summer home in Lake George, N.Y., two years ago, a routine inspection
revealed it had elevated levels of radon, a radioactive gas that can cause
lung
cancer. So she called a radon measurement and mitigation technician to
find the source.
“He went from room to room,” said Dr. Sugarman, a
pediatrician. But he stopped in his tracks in the kitchen, which had richly
grained cream, brown and burgundy granite countertops. His Geiger counter
indicated that the granite was emitting radiation at levels 10 times higher
than those he had measured elsewhere in the house.
“My first thought was, my pregnant daughter was coming for
the weekend,” Dr. Sugarman said. When the technician told her to keep her
daughter several feet from the countertops just to be safe, she said, “I had
them ripped out that very day,” and sent to the state Department of Health
for analysis. The granite, it turned out, contained high levels of uranium,
which is not only radioactive but releases radon gas as it decays. “The
health risk to me and my family was probably small,” Dr. Sugarman said, “but
I felt it was an unnecessary risk.”
As the popularity of granite countertops has grown in the
last decade — demand for them has increased tenfold, according to the Marble
Institute of America, a trade group representing granite fabricators — so
have the types of granite available. For example, one source, Graniteland (graniteland.com)
offers more than 900 kinds of granite from 63 countries. And with increased
sales volume and variety, there have been more reports of “hot” or
potentially hazardous countertops, particularly among the more exotic and
striated varieties from Brazil and Namibia.
“It’s not that all granite is dangerous,” said Stanley
Liebert, the quality assurance director at CMT Laboratories in Clifton Park,
N.Y., who took radiation measurements at Dr. Sugarman’s house. “But I’ve
seen a few that might heat up your Cheerios a little.”
Allegations that granite countertops may emit dangerous
levels of radon and radiation have been raised periodically over the past
decade, mostly by makers and distributors of competing countertop materials.
The Marble Institute of America has said such claims are “ludicrous” because
although granite is known to contain uranium and other radioactive materials
like thorium and potassium, the amounts in countertops are not enough to
pose a health threat.
Indeed, health physicists and radiation experts agree that
most granite countertops emit radiation and radon at extremely low levels.
They say these emissions are insignificant compared with so-called
background radiation that is constantly raining down from outer space or
seeping up from the earth’s crust, not to mention emanating from manmade
sources like X-rays, luminous watches and smoke detectors.
But with increasing regularity in recent months, the
Environmental Protection Agency has been receiving calls from radon
inspectors as well as from concerned homeowners about granite countertops
with radiation measurements several times above background levels. “We’ve
been hearing from people all over the country concerned about high
readings,” said Lou Witt, a program analyst with the agency’s Indoor
Environments Division.
Last month, Suzanne Zick, who lives in Magnolia, Tex., a
small town northwest of Houston, called the E.P.A. and her state’s health
department to find out what she should do about the salmon-colored granite
she had installed in her foyer a year and a half ago. A geology instructor
at a community college, she realized belatedly that it could contain
radioactive material and had it tested. The technician sent her a report
indicating that the granite was emitting low to moderately high levels of
both radon and radiation, depending on where along the stone the measurement
was taken.
“I don’t really know what the numbers are telling me about
my risk,” Ms. Zick said. “I don’t want to tear it out, but I don’t want
cancer either.”
The E.P.A. recommends taking action if radon gas levels in
the home exceeds 4 picocuries per liter of air (a measure of radioactive
emission); about the same risk for cancer as
smoking a half a pack of
cigarettes per day. In Dr. Sugarman’s kitchen, the readings were 100
picocuries per liter. In her basement, where radon readings are expected to
be higher because the gas usually seeps into homes from decaying uranium
underground, the readings were 6 picocuries per liter.
The average person is subjected to radiation from natural
and manmade sources at an annual level of 360 millirem (a measure of energy
absorbed by the body), according to government agencies like the E.P.A. and
the
Nuclear Regulatory Commission. The limit of additional exposure set by
the commission for people living near nuclear reactors is 100 millirem per
year. To put this in perspective, passengers get 3 millirem of cosmic
radiation on a flight from New York to Los Angeles.
A “hot” granite countertop like Dr. Sugarman’s might add a
fraction of a millirem per hour and that is if you were a few inches from it
or touching it the entire time.
Nevertheless, Mr. Witt said, “There is no known safe level
of radon or radiation.” Moreover, he said, scientists agree that “any
exposure increases your health risk.” A granite countertop that emits an
extremely high level of radiation, as a small number of commercially
available samples have in recent tests, could conceivably expose body parts
that were in close proximity to it for two hours a day to a localized dose
of 100 millirem over just a few months.
David J. Brenner, director of the Center for Radiological
Research at
Columbia University in New York, said the cancer risk from granite
countertops, even those emitting radiation above background levels, is “on
the order of one in a million.” Being struck by lightning is more likely.
Nonetheless, Dr. Brenner said, “It makes sense. If you can choose another
counter that doesn’t elevate your risk, however slightly, why wouldn’t you?”
Radon is the second leading cause of lung cancer after
smoking and is considered especially dangerous to smokers, whose lungs are
already compromised. Children and developing fetuses are vulnerable to
radiation, which can cause other forms of cancer. Mr. Witt said the E.P.A.
is not studying health risks associated with granite countertops because of
a “lack of resources.”
The Marble Institute of America plans to develop a testing
protocol for granite. “We want to reassure the public that their granite
countertops are safe,” Jim Hogan, the group’s president, said earlier this
month “We know the vast majority of granites are safe, but there are some
new exotic varieties coming in now that we’ve never seen before, and we need
to use sound science to evaluate them.”
Research scientists at
Rice University in Houston and at the New York State Department of
Health are currently conducting studies of granite widely used in kitchen
counters. William J. Llope, a professor of physics at Rice, said his
preliminary results show that of the 55 samples he has collected from nearby
fabricators and wholesalers, all of which emit radiation at
higher-than-background levels, a handful have tested at levels 100 times or
more above background.
Personal injury lawyers are already advertising on the Web
for clients who think they may have been injured by countertops. “I think it
will be like the mold litigation a few years back, where some cases were
legitimate and a whole lot were not,” said Ernest P. Chiodo, a physician and
lawyer in Detroit who specializes in toxic tort law. His kitchen counters
are granite, he said, “but I don’t spend much time in the kitchen.”
As for Dr. Sugarman, the contractor of the house she bought
in Lake George paid for the removal of her “hot” countertops. She replaced
them with another type of granite. “But I had them tested first,” she said.
Where to Find Tests and Testers
TO find a certified technician to determine whether
radiation or radon is emanating from a granite countertop, homeowners can
contact the American Association of Radon Scientists and Technologists (aarst.org).
Testing costs between $100 to $300.
Information on certified technicians and do-it-yourself
radon testing kits is available from the
Environmental Protection Agency’s Web site at
epa.gov/radon, as well as from state or
regional indoor air environment offices, which can be found at
epa.gov/iaq/whereyoulive.html.
Kits test for radon, not radiation, and cost $20 to $30. They are sold at
hardware stores and online.
Speaking recently at an energy
conference in Houston, Alan Greenspan said that in the national debate about
breaking our reliance on oil, one solution could make a real difference:
automakers' adoption of plug-in electric vehicles along with the
infrastructure to power them.
Asked how plug-in vehicles should be
fueled, the former Federal Reserve chief said, "No question about it — nuclear
power."
A combination of plug-in vehicles and
nuclear power needs to be part of the low-carbon pathway to America's energy
future. But government policy at both the state and federal levels must be the
driver.
Like hybrid vehicles already on the
market, plug-in vehicles use battery power in addition to an internal
combustion engine. But the plug-in vehicle does not require gasoline to
recharge its batteries. It can be plugged into an ordinary outlet found in
homes, enabling owners to recharge the batteries overnight.
While the market for plug-in vehicles
is improving, the electric-only driving range of the vehicles — typically 30
miles — is limited. Improvements in battery technology are crucial. Government
tax incentives for consumers and manufacturers would help spur mass production
of plug-in vehicles, which would bring down their cost and lead to the
development of smaller and more efficient batteries.
As with all clean-energy technologies,
including solar energy and wind turbines, the challenge is to provide
government support in a way that ensures they get off the drawing board and
are able to wean themselves from support as they become commercially viable on
their own.
With plug-in vehicles, that day may not
be too far off. Detroit's Big Three and several foreign automakers are moving
to commercialize plug-in vehicles. Toyota's plug-in vehicle is expected to go
into production next year, and General Motors, Ford and Daimler Chrysler are
testing their versions.
Meanwhile, there are compelling reasons
— energy security and the environment — for making greater use of nuclear
power. Its revival in the United States is under way, with 17 new nuclear
plants expected to go online by 2016. Innovative and standardized designs for
the new plants will make them more efficient and even safer than nuclear
plants currently operating.
In his recent book, "The Age of
Turbulence: Adventures in a New World," Greenspan writes that nuclear power is
an "obvious alternative" to coal in electric power generation. "Given the
steps that have been taken over the years to make nuclear energy safer and the
obvious environmental advantages it offers in reducing carbon dioxide
emissions, there is no longer a persuasive case against increasing nuclear
generation at the expense of coal."
"Nuclear power is a major means to
combat global warming," Greenspan said. "Its use should be avoided only if it
constitutes a threat to life expectancy that outweighs the gains it can give
us. By that criterion, I believe we significantly under-use nuclear power."
The growing danger from climate change
and threats to our energy security should concern all of us. It is clear that
if nuclear power and plug-in vehicles meet the conditions for expanded
production, they can be a big part of our salvation.
John C. Ringle of Corvallis is
professor emeritus, nuclear engineering at Oregon State University. He can be
reached at ringlejc@ne.orst.edu.
Molecule of the Week
January 14, 2008
Cisplatin
Cisplatin was first identified in 1845; it was
originally of interest during the development of coordination theory. At
that time, it was called Peyrone’s salt or Peyrone’s chloride, after its
discoverer, Michel Peyrone. In the mid-1960s, Cisplatin’s antitumor activity
was demonstrated, and it has served as the gold standard (should that be
“platinum standard”?) against which newer drugs are compared. Cisplatin is
probably best known for its role in helping Tour de France winner Lance
Armstrong fight testicular cancer. The trans isomer does not exhibit a
similar pharmacological effect.
The Radura is the international symbol indicating a food
product has been irradiated. All irradiated products sold in the United States
since 1986 must carry the Radura. The Radura is usually green and resembles a
plant in circle. The top half of the circle is dashed. As part of its
approval, the FDA requires that irradiated foods include labeling with either
the statement “treated with radiation” or “treated by irradiation,” along with
the Radura. Irradiation labeling requirements apply only to foods sold in
stores. For example, irradiated spices or fresh strawberries should be
labeled. Irradiation labeling does not apply to restaurant foods or processed
foods. The requirement is seen by consumer groups as a helpful warning to
consumers concerned about food irradiation. The food industry, on the other
hand sees the labeling requirement as a barrier to bring cheaper, safer foods
to consumers. Both groups agree the Radura labeling requirement is the primary
reason very few food products are irradiated.
The international radiation symbol (also known as trefoil)
first appeared in 1946, at the University of California, Berkeley Radiation
Laboratory. At the time, it was rendered as magenta, and was set on a blue
background. It is drawn with a central circle of radius R, an internal radius
of 1.5R and an external radius of 5R for the blades, which are separated from
each other by 60°.
A daughter product of 95Zr
is 95Nb (t1/2 = 35 days) which is released from
reprocessing plants and nuclear weapons tests. An indication of 95Nb
chemistry in soil is provided by zirconium, although uptake of niobium to
terrestrial plants occurs more readily than with zirconium. The behaviour of
95Nb in water resembles that of 95Zr but with a higher
proportion bound by particulates, colloids and soluble organic complexes. The
accumulation factor for sediment is higher for niobium than for zirconium.
As the staff at Los Alamos began research in the spring of 1943, the most
formidable problems it confronted were related to the new materials that would
be used in atomic bombs. These materials, uranium-235 and plutonium, were
largely unknown. Uranium-235 formed only a tiny fraction of natural uranium
(less than 1 percent) and plutonium had been discovered only two years earlier
at the University of California, Berkeley, Radiation Laboratory by chemistry
professor Glenn Seaborg and his associates. One of Seaborg's associates was
Emilio Segre', who had been a member of Enrico Fermi's team at the University
of Rome. Fermi and his colleagues originally thought that their bombardment of
uranium by slow neutrons in the mid-1930s had produced elements heavier than
uranium, or transuranic elements.
Further investigations by Otto Hahn and Fritz Strassman, German chemists at
the Kaiser Wilhelm Institute for Chemistry in Berlin, however, had revealed
that the uranium fissioned instead. The discovery of fission led in turn to
the discovery of the chain reaction that, if sustained, would provide the
energy for atomic weapons. Segre', who had fled the anti-Semitic laws imposed
by the fascist regime of Benito Mussolini in Italy, had found a job as a
research associate in UC's Radiation Laboratory. There, he investigated the
products of the bombardment of uranium by the cyclotron, then the most
powerful "atom-smasher" in the world.
After plutonium was discovered by Seaborg at the beginning of 1941, Segre'
established that the new element fissioned when struck by fast neutrons,
opening the way to its use in an atomic bomb. As Los Alamos was being set up
in the spring of 1943, he and his associates at Berkeley turned their
attention to spontaneous fission in uranium and plutonium. This process, if
proved, might cause an atomic weapon to predetonate, blowing the fissile
material apart before it had a chance to undergo an efficient chain reaction.
The possibility of spontaneous fission was real. After Fermi suggested it
and UC Berkeley chemist Willard F. Libby sought in vain for it in 1939, the
Russian physicists G.N. Flerov and K.A. Petrzhak discovered it in natural
uranium in 1940. Segre' had, consequently, to ensure that plutonium and
uranium-235 would not have a spontaneous fission rate large enough to cause
predetonation in the gun-assembled fission weapon planned.
Working with his graduate students -Owen Chamberlain, George Farwell,
Gustave Linenberger and Clyde Wiegand - Segre' and two UC chemists, Arthur
Wahl and Joseph Kennedy, measured rates of spontaneous fission in natural
uranium and plutonium in 1942 and 1943. The plutonium was made by the 60-inch
Crocker medical cyclotron at the UC Radiation Laboratory by the bombardment of
uranium-238 by deuterons, the ions of heavy-water (deuterium). By June 24,
1943, they found that such plutonium had a rate no greater than five
spontaneous fissions per kilogram each second, or 18 spontaneous fission per
gram of plutonium per hour, an acceptable rate.
These measurements at Berkeley were very difficult; the detectors used were
so sensitive that cellos playing in the next room were suspected of causing
more counts during the daytime than nighttime. The lights left on in the
daytime were found to produce photoelectrons that caused the disparity.
Leaving a flashlight on at night made up the difference.
The coincidence of pulses from several alpha- particles arising from the
radioactive decay of plutonium could also mimic spontaneous fission, and
extraordinary measures were taken to prepare materials of the right thickness
and to calibrate the ionization chambers used to detect fission fragments to
exclude these and other signals.
Although the results with plutonium produced in the Crocker medical
cyclotron were encouraging, several researchers suggested that plutonium
produced in nuclear reactors by the bombardment of uranium-238 by neutrons
might have an isotope, plutonium-240, that would be likely to fission
spontaneously. If this were only 1 percent of the reactor-produced plutonium
and it had a high-spontaneous fission rate, predetonation would be much more
likely.
At Los Alamos, chemists already planned to make plutonium that very highly
purified by removing lighter elements that might react with alpha particles
from decay to produce neutrons that could predetonate the bomb. Plutonium-240,
however, could not be chemically separated from plutonium-239 without building
huge isotope separation plants similar to those under construction at Oak
Ridge, Tenn., used to separate uranium-235 from uranium-238. To investigate
the possibility of spontaneous fission in plutonium, Los Alamos Director J.
Robert Oppenheimer invited Segre' and his group to move to Los Alamos to
continue their experiments there.
In mid-June 1945, Farwell recalled, "We all packed up - bags and counters,
detectors, electronics and all and went off to Los Alamos." Linenberger rode
shotgun in an Allied moving van that carried their delicate equipment, while
Farwell and Segre' flew in a DC-3, arriving on June 18.
Because of the delicacy of their detectors, the group could not remain in
the technical area around Ashley Pond, where most of the scientific activity
of the Laboratory was concentrated. They sought a place far from disturbances
that might upset their instruments and ended up in Pajarito Canyon, 14 miles
away. Shielded from radiation by the distance and housed in an old cabin, they
found the solitude they required. "It was a most poetic place," Segre'
recalled. "We went there by jeep every day. There was a bed in it (the cabin).
Somebody occasionally slept there."
The Dwight Young cabin in Pajarito Canyon.
The cabin Segre''s group used still stands in TA-18 and became known later
as "Dwight Young's" cabin. In the early days, it had been part of Ashley
Pond's dude ranch and was known as the Pajarito Club.
On June 17, 1943, word came to Los Alamos of a study of spontaneous fission
in polonium by Frederic Joliot and Pierre Auger in occupied Paris. The rate
they reported one spontaneous fission in every 1017 atoms of polonium
would be sufficient to rule out polonium as an element in the neutron
initiator then planned for atomic bombs, because the neutrons produced in the
process would pre-ignite the chain reaction. If a similar rate was found in
plutonium, it might rule out the use of that element as the nuclear explosive.
Although Los Alamos scientists believed the rate reported was too high, and
probably due to impurities in polonium that were difficult to remove,
Oppenheimer and the other members of the Laboratory's governing board agreed
to give Segre' all the necessary facilities to pursue their research in
Pajarito Canyon.
As June 1943 ended, the future of Los Alamos' program for a plutonium bomb
seemed in doubt. Only time would tell if plutonium could be used in nuclear
weapons and, if so, how. The resolution of those questions was to have a
pervasive effect on the new Laboratory and the world.
The Board of Health voted Tuesday to make New York the
nation's first city to ban artery-clogging artificial trans fats at
restaurants — from the corner pizzeria to high-end bakeries.
The board, which passed the ban unanimously, did give
restaurants a slight break by relaxing what had been considered a tight
deadline for compliance. Restaurants will be barred from using most frying
oils containing artificial trans fats by July and will have to eliminate the
artificial trans fats from all of its foods by July 2008.
Health Commissioner Thomas Frieden said recently that
officials seriously weighed complaints from the restaurant industry, which
argued that it was unrealistic to give them six months to replace cooking oils
and shortening and 18 months to phase out the ingredients altogether.
The ban contains some exceptions; for instance, it would
allow restaurants to serve foods that come in the manufacturer's original
packaging.
Trans fats are believed to be harmful because they contribute
to heart disease by raising bad cholesterol and lowering good cholesterol at
the same time. Some experts say that makes trans fats worse than saturated
fat.
The panel also passed another measure that has made
restaurants unhappy: Some that chose to inform customers about calorie content
will have to list the information right on the menu. The rule would generally
apply to fast-food restaurants and other major chains.
Trans fats are formed when liquid oils are made into solid
fats by adding hydrogen in a process called hydrogenation. A common example of
this is partially hydrogenated vegetable oil, which is used for frying and
baking and turns up in processed foods like cookies, pizza dough and crackers.
Trans fats, which are favored because of their long shelf life, are also found
in pre-made blends like pancake and hot chocolate mix.
The FDA estimates the average American eats 4.7 pounds of
trans fats each year.
Mayor Michael Bloomberg, who banned smoking in bars and
restaurants during his first term, is somewhat health-obsessed, and even
maintains a monthly weight-loss competition with one of his friends in order
to stay slim.
He has dismissed cries that New York is crossing a line by
trying to legislate diets.
"Nobody wants to take away your french fries and hamburgers —
I love those things, too," he said recently. "But if you can make them with
something that is less damaging to your health, we should do that."
Many food makers have stopped using trans fats on their own,
after the U.S. Food and Drug Administration began requiring companies to list
trans fat content on labels.
Fast-food restaurants and other major chains were
particularly interested in the board's decision on Tuesday, because for these
companies, a trans-fat ban wouldn't just involve substituting one ingredient
for another. In addition to overhauling recipes, they have to disrupt
nationwide supply operations and try to convince customers that the new french
fries and doughnuts will taste just as good as the originals.
Already, McDonald's Corp. has been quietly experimenting with
more than a dozen healthier oil blends but has not committed to a full switch.
At an investor conference last month, CEO Jim Skinner said the company is
making "very good progress," at developing an alternative, and vowed to be
ready for a New York City ban.
Wendy's International Inc. introduced a zero-trans fat oil in
August and Yum Brands Inc.'s KFC and Taco Bell said they also will cut the
trans fats from their kitchens.
Taco Bell worked for more than two years to find a
substitute, conducting blind consumer taste tests and extensive research, the
company said.
Chicago is
also considering its own trans fat law, which wouldn't ban them outright but
would severely restrict the amount that kitchens can use. The measure would
apply only to large restaurants, defined as those that make more than $20
million in sales per year.
New York's move to ban trans fats has mostly been applauded
by health and medical groups, although the American Heart Association warns
that if restaurants aren't given ample time to make the switch, they could end
up reverting to ingredients high in saturated fat, like palm oil.
Scientist finds 100 million-year-old bee
A scientist has found a 100 million-year-old bee trapped in amber,
making it possibly the oldest bee ever found.
"I knew right away what it was, because I had seen bees in younger
amber before," said George Poinar, a zoology professor at Oregon State
University.
The bee is about 40 million years older than previously found bees. The
discovery of the ancient bee may help explain the rapid expansion and
diversity of flowering plants during that time.
Poinar found the bee in amber from a mine in the Hukawng Valley of
northern Myanmar, formerly known as Burma. Many researchers buy bags of
amber from miners to search for fossils. Amber, a translucent semiprecious
stone, is a substance that begins as tree resin. The sticky resin entombs
and preserves insects, pollen and other small organisms.
Also embedded in the amber are four kinds of flowers. "So we can
imagine this little bee flitting around these tiny flowers millions of
years ago," Poinar said.
An article on his discovery will appear Friday in the journal Science,
co-authored by bee researcher Bryan Danforth of Cornell University.
In the competing journal Nature this week, there is an article about
the unraveling of the genetic map of the honeybee. The recently completed
sequencing of the honeybee genome already is giving scientists fresh
insights into the social insects.
Poinar's ancient male bee, Melittosphex burmensis, is not a honeybee
and not related to any modern bee family.
The pollen-eating bee has a few features of meat-eating wasps, such as
narrow hind legs, but the body's branched hairs are a key feature of
pollen-spreading bees.
The bee — about one-fifth the size of today's worker honeybee — has a
heart-shaped head.
But the ancient bee was probably an evolutionary dead end and may not
have given rise to modern bees, scientists said.
"It's exciting to see something that seems so different from what we
think of as modern bees," Danforth said. "It's not an ancestor of
honeybees, but probably was a species on an early branch of the
evolutionary tree of bees that went extinct."
Lucy fossil not coming to Smithsonian
The famous fossil of Lucy is scheduled to tour the United States, but one
place it won't be on display is the Smithsonian's National Museum of
Natural History.
"Not only is it not going to come to the Smithsonian Natural History
Museum, it is our position that we don't think it should leave Ethiopia,"
museum spokesman Randall Kremer said Wednesday.
Smithsonian scientists feel certain objects, such as Lucy, are too
valuable to travel and should remain in their homes, he said.
In announcing the plans to display the artifact, Ethiopian officials
had listed Washington as a stop on Lucy's tour, though they didn't specify
where in Washington the skeleton would go. The tour arrangements are being
made by the Houston Museum of Natural Science and not all locations have
been finalized.
The fossilized remains were discovered in 1974 in the remote,
desert-like Afar region in northeastern Ethiopia. Lucy is classified as an
Australopithecus afarensis, which lived in Africa between about 4 million
and 3 million years ago, and is the earliest known hominid.
Most scientists believe afarensis stood upright and walked on two feet,
but they argue about whether it had ape-like agility in trees. The loss of
that ability would suggest crossing a threshold toward a more human
existence.
Baby
fossil adds to debate over our origins
3.3
million-year-old juvenile skeleton came from same species as ‘Lucy’
The
Associated Press
Updated: 10:13 a.m.
PT Sept 20, 2006
NEW YORK
- Scientists have discovered a remarkably complete skeleton of a 3-year-old
female from the hominid species represented by “Lucy.”
The discovery should fuel
a contentious debate about whether this species, which walked upright, also
climbed and moved through trees easily like an ape.
The remains are 3.3
million years old, making them the oldest known skeleton of such a youthful
human ancestor.
“It’s pretty unbelievable”
to find such a complete fossil from that long ago, said scientist Fred Spoor.
“It’s a once-in-a-lifetime find.”
Spoor, professor of
evolutionary anatomy at University College London, describes the fossil in
Thursday’s issue of the journal
Nature with Zeresenay Alemseged of the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany, and other scientists.
The skeleton was
discovered in 2000 in northeastern Ethiopia. Scientists have spent five
painstaking years removing the bones from sandstone, and the job will take years
more to complete.
Judging by how well it was
preserved, the skeleton may have come from a body that was quickly buried by
sediment in a flood, the researchers said.
The skeleton has been
nicknamed “Selam,” which means means “peace” in several Ethiopian languages.
More like ape or human? The creature was a
member of
Australopithecus afarensis, which lived in Africa between about 4 million
and 3 million years ago. The most famous representative of the species is Lucy,
discovered in Ethiopia in 1974, which lived about 100,000 years after the
newfound specimen.
Most scientists believe A.
afarensis stood upright and walked on two feet, but they argue about whether it
had apelike agility in trees.
That climbing ability
would require anatomical equipment like long arms, and A. afarensis had arms
that dangled down to just above the knees. The question is whether such features
indicate climbing ability or just evolutionary baggage.
So far, analysis of the
new fossil hasn’t settled the argument but does seem to indicate some climbing
ability, Spoor said.
While the lower body is
very humanlike, he said, the upper body is apelike:
·The shoulder blades resemble those of a gorilla rather than a modern
human.
·The neck seems short and thick like a great ape’s, rather than the more
slender version humans have to keep the head stable while running.
·The organ of balance in the inner ear is more apelike than human.
·The fingers are very curved, which could indicate climbing ability,
“but I’m cautious about that,” Spoor said. Curved fingers have been noted for
afarensis before, but their significance is in dispute.
A big question is what the
foot bones will show when their sandstone casing is removed, he said. Will there
be a grasping big toe like the opposable thumb of a human hand? Such a chimplike
feature would argue for climbing ability, he said.
Yet, to resolve the
debate, scientists may have to find a way to inspect vanishingly small details
of such old bones, to get clues to how those bones were used in life, he said.
Debate will continue Bernard Wood of
George Washington University, who didn’t participate in the discovery, said in
an interview that the fossil provides strong evidence of climbing ability. But
he also agreed that it won’t settle the debate among scientists, which he said
“makes the Middle East look like a picnic.”
Overall, he wrote in a
Nature commentary, the discovery provides “a veritable mine of information about
a crucial stage in human evolutionary history.”
The fossil revealed just
the second hyoid bone to be recovered from any human ancestor. This tiny bone,
which attaches to the tongue muscles, is very chimplike in the new specimen,
Spoor said.
While that doesn’t
directly reveal anything about language, it does suggest that whatever sounds
the creature made “would appeal more to a chimpanzee mother than a human
mother,” Spoor said.
The fossil find includes
the complete skull, including an impression of the brain and the lower jaw, all
the vertebrae from the neck to just below the torso, all the ribs, both shoulder
blades and both collarbones, the right elbow and part of a hand, both knees and
much of both shin and thigh bones. One foot is almost complete, providing the
first time scientists have found an A. afarensis foot with the bones still
positioned as they were in life, Spoor said.
The work was funded by the
National Geographic Society, the Institute of Human Origins at Arizona State
University, the Leakey Foundation and the Planck institute.
Designer creates floating bed Mon Aug 7, 8:31
AM ET A young Dutch architect has created a floating bed which hovers above
the ground through magnetic force and comes with a price tag of 1.2 million
euros ($1.54 million). Janjaap Ruijssenaars took inspiration for the bed -- a
sleek black platform, which took six years to develop and can double as a
dining table or a plinth -- from the mysterious monolith in Stanley Kubrick's
1968 cult film "2001: A Space Odyssey." "No matter where you live all
architecture is dictated by gravity. I wondered whether you could make an
object, a building or a piece of furniture where this is not the case -- where
another power actually dictates the image," Ruijssenaars said. Magnets built
into the floor and into the bed itself repel each other, pushing the bed up
into the air. Thin steel cables tether the bed in place. "It is not
comfortable at the moment," admits Ruijssenaars, adding it needs cushions and
bedclothes before use. Although people with piercings should have no problem
sleeping on the bed, Ruijssenaars advises them against entering the magnetic
field between the bed and the floor. They could find their piercing suddenly
tugged toward one of the magnets.
Biochemically, starch is a combination of two polymeric carbohydrates (polysaccharides) called amylose and amylopectin. Amylose is constituted by glucose monomer units joined to one another head-to-tail forming alpha-1,4 linkages. Amylopectin differs from amylose in that branching occurs, with an alpha-1,6 linkage every 24-30 glucose monomer units. The overall structure of amylopectin is not that of a linear polysaccharide chain since two glucose units frequently form a branch point, so the result is the coiled molecule most suitable for storage in starch grains. Both amylopectin and amylose are polymers of glucose, and a typical starch polymer chain consists of around 2500 glucose molecules in their varied forms of polymerisation. In general, starches have the formula (C6H10O5)n.
This fuel cell (right) is being tested at Ft. Belvoir as a possible replacement for the main standard-issue military battery (front left). For comparison, an AA battery is in the foreground.
Morning Edition, May 8, 2006 · Cell phones and laptop computers make a lot of different sounds, but the saddest and most plaintive one may be the beep that means "Low Battery." People hear that beep all the time, because most so-called "wireless" gadgets can't run for very long before they have to get plugged into a wall and spend hours recharging. That's why technology companies -- and even the U. S. military -- are working on new power sources that last longer than today's batteries. One unexpected answer is a highly flammable liquid fuel that has been around for over 300 years.A Lighter Battery Load for U.S. TroopsThe fuel is called methanol, or wood alcohol. It used to get distilled from wood; now it is mostly synthesized using natural gas. A few years ago, U.S. Army engineer Chris Bolton started wondering if methanol could power military gadgets. But Bolton knew commanders were "not going to be equipping the troops with gasoline that is going to turn them into human torches every time they get shot." So first he performed a crude, but important, safety experiment. "We put methanol canisters on a mannequin and basically shot him with tracer rounds," he says. "We couldn't set it alight." That was good to know, since war zones have a lot of flying bullets -- but it's hard to find batteries or rechargers on the battlefield. So Bolton says a typical infantry platoon needs to carry more than 150 pounds of batteries if it is going on a five-day mission. The batteries power a laundry list of electronics. "They have night vision devices. They have image intensification devices, IR devices, laser range finders, radios, GPS, even a few laptops out there," says Bolton. "The average energy [need] for the soldier is going up because we give him more electronics."To keep those electronics running, the military is taking a close look at methanol. Just a teacup holds a huge amount of energy: four or five times more than a battery of the same size and weight. At his Ft. Belvoir laboratory near Washington, D.C., Bolton recently showed off one methanol power pack he's testing. It's a square, green device the size of an office phone. Bolton picked up a plastic bottle of methanol and screwed it onto the device. "It has a simple little on-and-off switch," he explained, switching it on. "You hear some noise on start up, it's basically a little chemical plant."It's called a fuel cell. Tiny pumps move the methanol through a chemical process that extracts the energy without setting the fuel on fire. The idea has been around for a long time, but now fuel cells are getting smaller. Bolton expects this system to shrink down even more in the next year. He says special operations troops, which often go out on secret missions that last for days, could be carrying it within two years.More Hours on Your Cell PhoneThe military's real warriors could soon be followed by the business world's "road warriors." Executives who travel all the time hate having to wait for a battery to recharge. That's why a slew of technology companies are also looking at methanol. "We get complaints that the battery doesn't last long enough. We need something better," says Jerry Hallmark, who works on energy technologies for Motorola. He predicts early methanol-powered devices will be relatively expensive, so they will be "somewhat of a niche" product. "It's going to be the high-end user, the road warrior, who is going to use something like this. But there is a definite need," he says. Eventually, he and other industry experts believe the demand for methanol fuel cells will reach beyond traveling executives. Future gadgets on the drawing boards, such as multimedia laptops and video cellphones, have features that will hog more and more power. And although computer companies have started to make machines that use less power, and batteries do improve a little bit every year, Hallmark believes that those advances are not going to be enough. "People want to have video on their cell phones, they want to have music, and they want to have high-speed Internet connection. And they want to have this hours a day," he says. "At some point, a battery is not going to be able to keep up with that demand."But before methanol can meet that demand, fuel cells have to get smaller. They also have to get cheaper; right now they're often made with platinum, an expensive metal.Making a Market for MethanolStill, Hallmark thinks that several new developments make methanol fuel cells look much more plausible. One is a decision by federal transportation officials. Starting next year, they'll allow people to take small, sealed canisters of methanol onto airplanes. "If that hadn't happened, and we had devices that people couldn't travel with, that really would limit the market tremendously," Hallmark explains.Another important development is that some well-known companies are talking about ways of making methanol easy to buy, in little cartridges. For instance, the BIC company -- known for its disposable lighters -- says it may soon be possible to walk into a convenience store in Hong Kong or New York, and buy a cheap methanol cartridge that could power your laptop for hours. "We'll be putting methanol and water in a plastic cartridge," says Rick McEttrick, BIC's senior manager for consumer products. He says his company has never made batteries. But, every day, it does make four million pocket lighters, "which is basically a liquid fuel that we put into a plastic body, which is very, very similar to what a micro fuel cell cartridge will be."Other companies are starting to construct methanol-guzzling prototypes of everyday electronics. Gregory Dolan of the Methanol Institute, an industry group, says they last longer than battery-powered devices. "For example, Toshiba has an MP3 player which runs for 60 hours on just 10 milliliters of methanol. Samsung has demonstrated a laptop that runs for 15 hours," Dolan says. "Hitachi has already demonstrated a cell phone that has two and a half times the run time of current lithium technology and standby time of as much as a month before you have to put in a new fuel cell cartridge."But Dolan says fuel cells probably wouldn't immediately replace batteries. That's because batteries are better at handling spikes in power demand, like those that occur when you first turn a machine on. So someday, your wireless device may end up having a fuel cell that's there to keep the battery recharged, without having to plug it in and wait.
Electrolysis of Water
Here is a very simple way to demonstrate that water contains hydrogen and oxygen. In order to show electrolysis, you'll need a 9 volt battery, some bits of wire, tape, a small saucer, some salt, and two small pencils sharpened at each end.
You can use this demonstration in lower grades just to illustrate that oxygen and hydrogen are the components of water. But we've also included enough information to make it useful for high school chemistry students.
However you make use of the demo, it only takes seconds to set up, requires no special equipment, and it works every time! The first time we saw this demonstrated we were amazed at how simple it is to separate water into its components ... no complicated tubing, glassware, and electrical power supply needed!
You can use a clear glass dish, and show the process on an overhead projector.
Here's the setup. That's all there is!
Add a sprinkle or two of salt to the water ... not much is needed. Each pencil becomes an electrode, and the moment you hook up the battery, bubbles will begin appearing at the tip of each pencil: oxygen at the positive electrode, and hydrogen at the negative one.
You can try collecting the gases with inverted small test tubes, and use a burning splint to test for hydrogen (the tube will pop) and a glowing splint to test for oxygen (the splint will burst into flame).
Below on this page we've included some terms describing electrolysis, and an explanation of the process that is suitable for high school chemistry students.
When you add salt to the water, the salt ions (which are highly polar) help pull the water molecules apart into ions too. Each part of the water molecule has a charge. The OH- ion is negative, and the H+ ion is positive.
This solution in water forms an electrolyte, allowing current to flow when a voltage is applied. The H+ ions, called cations, move toward the cathode (negative electrode), and the OH- ions, called anions, move toward the anode (positive electrode).
If you add some universal indicator solution to the salt water, you will be able to see a colour change corresponding to acid near the cathode (H+ ions in water) and base near the anode (OH- ions in water).
At the anode, water is oxidized:
2H2O --> O2 + 4H+ + 4e-
At the cathode, water is reduced:
4H2O + 4e- --> 2H2 + 4OH-
Note that there is a net balance of electrons in the water.
Bubbles of oxygen gas (O2) form at the anode, and bubbles of hydrogen gas (H2) form at the cathode.
The bubbles are easily seen. Twice as much hydrogen gas is produced as oxygen gas.
Fe2+(aq)
+ 2 e- 
)
Here is a very simple way to demonstrate that water contains hydrogen and oxygen. In order to show electrolysis, you'll need a 9 volt battery, some bits of wire, tape, a small saucer, some salt, and two small pencils sharpened at each end.
Here's the setup. That's all there is!
