Energetic Nanoparticles Swing Sunlight Into Electricity

The electrons in nanoparticles of noble metal oscillate together apace with the frequency of the light. This phenomenon can be exploited to produce better and cheaper solar cells, scientists at Chalmers University of Technology in Sweden have shown. Electricity-generating solar cells are one of the most attractive alternatives for creating a long-term sustainable energy system, but thus far solar cells have not been able to compete economically with fossil fuels. Researchers are now looking at how nanotechnology can contribute in bringing down the cost. Solar cells are constructed of layers that absorb sunlight and convert it to electrical current. Thinner solar cells can yield both cheaper and more plentiful electricity than today's cells, if their capacity to absorb sunlight is optimized. One way to enhance the absorption of the solar harvesting material in a solar cell is to make use of nanoparticles of noble metal. Carl Hägglund at Chalmers has looked at how this can be done in his recently completed doctoral dissertation. The particles involved have special optical properties owing to the fact that their electrons oscillate back and forth together at the same rate as the frequency of the light, that is, the color of the light. The particles catch the light as tiny antennas and via the oscillations the energy is passed on as electricity. These oscillations, plasmons, are very forceful at certain so-called plasmon resonance frequencies, which in turn are influenced by the form, size, and surroundings of the particles. "What we've done is to make use of nanotechnology to produce the particles and we've therefore been able to determine the properties and see how they can enhance the absorption of light of different colors," says Carl Hägglund. In the context of solar cells, the great challenge is to efficiently convert the energy that is absorbed in the electron oscillation to energy in the form of electricity.
"We show that it is precisely the oscillations of the particles that yield the energy, how it is transmitted to the material and becomes electricity. It might have turned out, for example, that the oscillations simply generated heat instead," says Carl Hägglund. The efficiency of the best solar cells today is already very high. The possibility of achieving even better solar cells therefore lies in using less material and in lowering production costs. With solar cells of specially designed nanoparticles of gold, which is what Carl Hägglund has looked at, a layer only a few nanometers thick is required for the particles to be able to absorb light in an efficient way. The dissertation examines the effect of nanoparticles of noble metal on two different types of solar cells, which can be said to represent two extremes. In one type of solar cell the light is absorbed in molecules on a surface, and in the other type deep inside the material. The experimental and theoretical results show that the particles can help transmit the light's energy to useful electricity in several different ways and that it's possible to enhance the absorption of solar cells both on the surface and deep inside via different mechanisms. This work has been carried out within the framework of a materials science research program (PhotoNano) funded by the Swedish Foundation for Strategic Research.
by Chalmers University of Technology.

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New Material Is Capable Of Eliminating Pollutants By The Hydrocarbon Industry

A research team of the University of Granada has managed to produce what they consider the most useful material to date to eliminate pollutants such as benzene, toluene and xylene, organic solvents widely used in the hydrocarbon industry and generated by road traffic in cities. The world-wide problem of the exposure to aromatic hydrocarbons has mainly focused its attention on benzene, which is considered to be harmful to health, even in low concentrations. This material is a monolithic carbon aerogel with the advantage of not only being able to retain these pollutants: it can also be easily regenerated and can therefore be used in several cycles. This research has been carried out by David Fairén Jiménez, from the Department of Inorganic Chemistry at the University of Granada, and directed by lecturers Carlos Moreno Castilla and Francisco Carrasco Marín. The aim of this study was to prepare and describe a series of new materials – monolithic carbon aerogels – as adsorbers of benzene, tolene and xylene (BTX).

The study of the elimination of volatile organic compounds from anthropogenic sources – road traffic in cities, solvents, industry, etc. – such as BTX, is very important as these substances are highly pollutant. In order to eliminate these pollutants, “it is necessary to use materials with a high concentration of micropores, which is where the absorption of pollutants takes place, but these pores must be the correct size and properly arranged. Thus, we achieve a high level of efficiency when eliminating and retrieving BTX after the saturation of the material”, said David Fairén.

Furthermore, the design of the adsorbent bed must allow a sufficient contact for the elimination of compounds and at the same time avoid a decrease in pressure. Finally, the material used must withstand the mechanical forces of vibration and movement. David Fairén states that “the monolithic carbon aerogels, which are the materials we worked with, satisfy all these requirements.

This research provides a methodology for the study of porous samples by comparing definition techniques of the more used surfaces, such as gas adsorption, with other difficult techniques, such as small-angle X-ray scattering (SAXS).
These techniques provide information on the characteristics of these materials and about the physical conditions of pollutants within the pores. And, researchers have obtained materials with better properties than other published results regarding the elimination of pollutants such as benzene, toluene and xylene.

This is because the materials have a high capacity to retain pollutant compounds and they can be easily regenerated and used in several cycles. The design of these samples, as they can be synthesized in the required way, makes them suitable to be applied in streams with a high gas flow without a decrease in the pressure of the adsorbent bed.

The results of this research have been published in Carbon, the Journal of Physical Chemistry and Langmuir.

by University of Granada

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Pemodelan pengukuran kerapatan tulang dengan teknik radiasi dual X-rays pada Bone Densitometer

Literatures study for mathematic model of data processing system in the bone densitometry using Dual Energy X-ray Absorptiometry method has been done. The result of study shows that there are six mathematic equations that used sequentially to get information about bone density. By knowing equations of the mathematic model, a bone densitometry using the same method could hopefully be developed in PRPN.
Keywords: X-ray, dual energy, attenuation coefficient, attenuation ratio, element composition, mass density, tissue weight, mathematics model, fat, lean, soft tissue.
Amin HD

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Energetic Nanoparticles Swing Sunlight Into Electricity

The electrons in nanoparticles of noble metal oscillate together apace with the frequency of the light. This phenomenon can be exploited to produce better and cheaper solar cells, scientists at Chalmers University of Technology in Sweden have shown. Electricity-generating solar cells are one of the most attractive alternatives for creating a long-term sustainable energy system, but thus far solar cells have not been able to compete economically with fossil fuels. Researchers are now looking at how nanotechnology can contribute in bringing down the cost.

Solar cells are constructed of layers that absorb sunlight and convert it to electrical current. Thinner solar cells can yield both cheaper and more plentiful electricity than today's cells, if their capacity to absorb sunlight is optimized.

One way to enhance the absorption of the solar harvesting material in a solar cell is to make use of nanoparticles of noble metal. Carl Hägglund at Chalmers has looked at how this can be done in his recently completed doctoral dissertation.

The particles involved have special optical properties owing to the fact that their electrons oscillate back and forth together at the same rate as the frequency of the light, that is, the color of the light. The particles catch the light as tiny antennas and via the oscillations the energy is passed on as electricity. These oscillations, plasmons, are very forceful at certain so-called plasmon resonance frequencies, which in turn are influenced by the form, size, and surroundings of the particles.

"What we've done is to make use of nanotechnology to produce the particles and we've therefore been able to determine the properties and see how they can enhance the absorption of light of different colors," says Carl Hägglund.

In the context of solar cells, the great challenge is to efficiently convert the energy that is absorbed in the electron oscillation to energy in the form of electricity.

"We show that it is precisely the oscillations of the particles that yield the energy, how it is transmitted to the material and becomes electricity. It might have turned out, for example, that the oscillations simply generated heat instead," says Carl Hägglund.

The efficiency of the best solar cells today is already very high. The possibility of achieving even better solar cells therefore lies in using less material and in lowering production costs.

With solar cells of specially designed nanoparticles of gold, which is what Carl Hägglund has looked at, a layer only a few nanometers thick is required for the particles to be able to absorb light in an efficient way.

The dissertation examines the effect of nanoparticles of noble metal on two different types of solar cells, which can be said to represent two extremes. In one type of solar cell the light is absorbed in molecules on a surface, and in the other type deep inside the material.

The experimental and theoretical results show that the particles can help transmit the light's energy to useful electricity in several different ways and that it's possible to enhance the absorption of solar cells both on the surface and deep inside via different mechanisms.

This work has been carried out within the framework of a materials science research program (PhotoNano) funded by the Swedish Foundation for Strategic Research.
by Chalmers University of Technology.

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Study of Physical Processes Of Charged Particles Radiation Detection

This paper considers the physical processes which govern the operation of semiconductors particle detectors. It contains it discussion of; the production of hole-electron pairs by energetic particle in solids; the motion of the pairs under the influence of an electric field and the presence of trapping and recombination; the current wave shape resulting from transport of these carriers; the production of the high electric feilds to facilitate transport in the single conductivity and junction devices; and the influence of high density of the holes and electrons along particle tracks on the transport processes.
Gunarwan Prayitno

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Human Shadows on the Seas

In 1980, after college, I joined the crew of a sailboat partway through a circumnavigation of the globe. Becalmed and roasting one day during a 21-day crossing of the western Indian Ocean, several of us dived over the side. Within a few swimming strokes, the bobbing hull seemed a toy over my shoulder as I glanced back through my diving mask. Below me, my shadow and the boat’s dwindled to the vanishing point in the two-mile-deep water. Human activity seemed nothing when set against the sea itself.
Just a few weeks later, on an uninhabited island in a remote part of the Red Sea, I was proved wrong. The shore above the tide line was covered with old light bulbs, apparently tossed from the endless parade of ships over the years.
Now scientists are building the first worldwide portrait of such dispersed human impacts on the oceans, revealing a planet-spanning mix of depleted resources, degraded ecosystems and disruptive biological blending as species are moved around the globe by accident and intent.
A paper in the Feb. 15 issue of the journal Science is the first effort to map 17 kinds of human ocean impacts like organic pollution, including agricultural runoff and sewage; damage from bottom-scraping trawls; and intensive traditional fishing along coral reefs.
About 40 percent of ocean areas are strongly affected, and just 4 percent pristine, according to the review. Polar seas are in the pristine category, but poised for change. Some human impacts are familiar, like damage to coral reefs and mangrove forests through direct actions like construction and subtler ones like the loss of certain fish that shape ecosystems.
Others were a surprise, said Benjamin S. Halpern, the lead author and a scientist at the National Center for Ecological Analysis and Synthesis in Santa Barbara, Calif. He said continental shelves and slopes proved to be the most heavily affected areas, particularly along densely populated coasts.
The most widespread human fingerprint is a slow drop in the pH of surface waters around the world as a portion of the billions of tons of carbon dioxide added to the atmosphere from fuel and forest burning each year is absorbed in water, where it forms carbonic acid.
That progressive shift in ocean chemistry could eventually disrupt shell-forming plankton and reef-building species, particularly where other impacts, including rising temperatures from human-caused global warming, create simultaneous stresses, many marine biologists say.
“I study this stuff all the time and didn’t expect the impacts to be as pervasive as we found,” Dr. Halpern said.
The review provides a baseline necessary for tracking further shifts, he said. It also identifies some unanticipated trouble spots, similar to terrestrial biodiversity “hot spots” that environmental groups have identified over the years.
Such an analysis is long overdue, many marine biologists said in interviews. People’s conservation concerns have mainly focused on land, even though the seas cover two-thirds of the planet and are a vital source of food and pleasure.
Sylvia Earle, an oceanographer and National Geographic Society “explorer in residence,” said people care only about what they know. A big question now is whether such surveys are providing too little knowledge, too late.
“We learned more about the nature of the ocean in the latter part of the 20th century than during all preceding human history,” Dr. Earle said. “But we also lost more.”
A separate mapping effort published this month focused on introduced invasive species and found that 84 percent of the world’s coastal waters were affected, with Arctic waters next in line as shipping there grows in a warming world.
More than half the introduced species that take hold are having deleterious effects, said Jennifer Molnar, a conservation scientist at the Nature Conservancy who led that study, which was published in the journal Frontiers in Ecology and the Environment.
The House of Representatives is considering legislation aimed at tightening controls on the ballast water that stabilizes freighters when they are not full. Ballast water and organisms clinging to hulls and anchors have been the source of many costly marine invasions, including the introduction of zebra mussels to American waters and the comb jelly, a small jellyfish, to the Black Sea.
That species exploded after its accidental introduction in 1993, vacuuming up plankton until it made up 90 percent of the sea’s life by weight, causing fisheries to collapse. Its population there has since crashed, partly because of the arrival of a species of jellyfish that eats the established invader.
In May, invasive species will be a significant subject at the meeting of the world’s nations to assess the progress of the Convention on Biological Diversity.
Even as efforts to gauge human effects intensify, other scientists are simply trying to survey marine species large and small, an enormous task given how little is known about the oceans.
The hub for this work is the Census of Marine Life, a 10-year project initiated under the Alfred P. Sloan Foundation that is scheduled to produce a first synthesis report on marine species in 2010.
More than 2,000 scientists from 81 countries have chipped in, said Michael Feldman of the Consortium for Ocean Leadership, a group in Washington running the global project.
Since 2003, the project has discovered more than 5,300 species, Mr. Feldman said, adding: “We’ve only been able to formally describe a few hundred so far. They’re still discovering things at a rate we don’t even know what to do with.”
There is a growing sense of urgency among marine researchers in cataloging what is there, what is being threatened and what is already a fading memory.
Recent books, including “The Unnatural History of the Sea” by the marine scientist Callum Roberts, have painted vivid portraits of how much more abundant marine resources were a few generations ago, a situation well known to anyone who has worked in a fishery.
In the 1970s, I worked summers for the Rhode Island marine fisheries agency. At one point, I was tagging lobsters as part of an effort to find ways to revive depleted populations. A crusty old custodian in the laboratory, Jim Pimentel, reminisced about how different things had been a few decades earlier.
“We used lobsters for cod bait,” Mr. Pimentel said.
Looking ahead, Jane Lubchenco, a marine biologist at Oregon State University, said a wide array of efforts is required to sustain productive, if altered, seas. Among the needed steps, Dr. Lubchenco said, are expanding protected marine areas and curbing pollution, including carbon dioxide.
“We cannot go back in time to some past system,” Dr. Lubchenco said. “But we can protect and restore the functioning of today’s ecosystems so they can be as healthy, productive and resilient as possible.”
By ANDREW C. REVKIN

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Gene That Controls Ozone Resistance Of Plants Could Lead To Drought-resistant Crops

Biologists at the University of California, San Diego, working with collaborators at the University of Helsinki in Finland and two other European institutions, have elucidated the mechanism of a plant gene that controls the amount of atmospheric ozone entering a plant’s leaves.
Their finding helps explain why rising concentrations of carbon dioxide in the atmosphere may not necessarily lead to greater photosynthetic activity and carbon sequestration by plants as atmospheric ozone pollutants increase. And it provides a new tool for geneticists to design plants with an ability to resist droughts by regulating the opening and closing of their stomata—the tiny breathing pores in leaves through which gases and water vapor flow during photosynthesis and respiration.
“Droughts, elevated ozone levels and other environmental stresses can impact crop yields,” said Jean Chin, who oversees membrane protein grants at the National Institute of General Medical Sciences, which partially funded the research. “This work gives us a clearer picture of how plants respond to these kinds of stresses and could lead to new ways to increase their resistance.”
The discovery is detailed in the advance online publication of the journal Nature by biologists at UCSD, University of Helsinki in Finland, University of Tartu in Estonia and the University of the West of England. Last year, the journal published another study by British researchers that found that ozone generated from the nitrogen oxides of vehicle emissions would significantly reduce the ability of plants to increase photosynthesis and store the excess carbon in the atmosphere projected from rising levels of carbon dioxide.
“When ozone enters the leaf through the stomatal pores, it damages the plants photosynthetic machinery and basically causes green leaves to lose their color, a process called chlorosis,” said Julian Schroeder, a professor of biological sciences at UC San Diego and one of the principal authors of the recent study. “Plants have a way to protect themselves and they do that by closing the stomatal pores when concentrations of ozone increase.”
While this protective mechanism minimizes the damage to plants, he adds, it also minimizes their ability to photosynthesize when ozone levels are high, because the stomatal pores are also the breathing holes in leaves through which carbon dioxide enters leaves. The result is diminished plant growth or at least less than one might expect given the rising levels of carbon dioxide.
Some scientists assessing the impacts of rising greenhouse gases had initially estimated that increased plant growth generated from extra carbon dioxide in the atmosphere could sequester much of the excess atmospheric carbon in plant material. But in a paper published last July in Nature, researchers from Britain’s Hadley Centre for Climate Prediction and Research concluded that the damage done to plants by increasing ozone pollution would actually reduce the ability of plants to soak up carbon from the atmosphere by 15 percent which corresponds to about 30 billion tons of carbon per year on a global scale---a dire prediction given that humans are already putting more carbon into the atmosphere than plants can soak up.
The discovery of the ozone-responsive plant gene was made when Jaakko Kangasjarvi and his collaborators at the University of Helsinki in Finland found a mutant form of the common mustard plant, Arabidopsis, that was extremely sensitive to ozone. They next found that this mutant does not close its stomatal pores in response to ozone stress.
“When the mutant plant is exposed to ozone, the leaves lose their dark green color and eventually become white,” said Kangasjarvi, who is also one of the principal authors of the study. “This is because the stomatal pores in the leaves stay open even in the presence of high ozone and are unable to protect the plant.”
The scientists found that the gene responsible for the mutation is essential for the function of what they called a “slow or S-type anion channel.” Anions are negatively charged ions and these particular anion channels are located within specialized cells called guard cells that surround the stomatal pores. The gene was therefore named SLAC1 for “slow anion channel 1.”
Guard cells close stomatal pores in the event of excess ozone or drought. When this gene is absent or defective, the mutant plant fails to close its stomatal pores.
In 1989, Schroeder discovered these slow anion channels in guard cells by electrical recordings from guard cells using tiny micro-electrodes. He predicted that these anion channels would be important for closing the stomatal breathing pores in leaves under drought stress.
“The model we proposed back then was that the anion channels are a kind of electrical tire valve in guard cells, because our studies suggested that closing stomatal pores requires a type of electrically controlled deflation of the guard cells,” he said. “But finding the gene responsible for the anion channels has eluded many researchers since then.”
The latest study shows that the SLAC1 gene encodes a membrane protein that is essential for the function of these anion channels. “We analyzed a lot of mechanisms in the guard cells and, in the end, the slow anion channels were what was missing in the mutant,” said Yongfei Wang, a post doctoral associate in Schroeder’s lab and co-first author of the paper.
The scientists showed that the SLAC1 gene is required for stomatal closing to various stresses, including ozone and the plant hormone abscisic acid, which controls stomatal closing in response to drought stress. Elevated carbon dioxide in the atmosphere also causes a partial closing of stomatal pores in leaves. By contrast, the scientists found, the mutant gene does not close the plants’ stomatal pores when carbon dioxide levels are elevated.
“We now finally have genetic evidence for the electric tire valve model and the gene to work with,” said Schroeder.
Because the opening and closing of stomatal pores also regulates water loss from plants, Schroeder said, understanding the genetic and biochemical mechanisms that control the guard cells during closing of the stomatal pores in response to stress can have important applications for agricultural scientists seeking to genetically engineer crops and other plants capable of withstanding severe droughts.
“Plants under drought stress will lose 95 percent of their water through evaporation through stomatal pores, and the anion channel is a central control mechanism that mediates stomatal closing, which reduces plant water loss,” he said.
The study was financed by grants from the National Science Foundation and the National Institute of General Medical Sciences.
by University of California - San Diego.

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Study of verification techniques for nuclear material safeguards and security

The presence of nuclear materials at any nuclear facilities must be known as safeguards purpose through the knowledge of position, form or type and the amount. The clarification of the position, the type and the amount must be reported to International Atomic Energy Agency (IAEA) as the international regulatory body. Then IAEA will veriry that report. The verification must be done to know that there is no difference of the amount, and to give assurance to the international community that the nuclear material used only to non military purpose. To carry out the verification, several verification techniques such non-destructive analysis such as gamma spectrometry, neutron counting, serveillance technique, unattended and remote monitoring and environmental sampling are explained in this paper to give the impression how those techniques are implemented.
Ignatius Joko Irianto

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Now Windows Users Have Their Own Skinny Contender in the Battle of the Lightweight Laptops

It’s hard to be the Lenovo ThinkPad X300. While the rest of the world was fawning over Apple’s ultraslim MacBook Air, Lenovo’s laptop entered the world with little fanfare, even though it is 0.1 of a pound lighter and runs Windows Vista.

The X300 gets up to 10 hours of battery life on one charge and has an internal metal cage to keep it from snapping during the rigors of travel. It has a 1.2-gigahertz Intel Core 2 Duo processor and a 64-gigabyte solid-state drive that uses flash memory instead of a spinning hard drive. But that last feature contributes to the laptop’s high price: it starts at $2,548.

Unlike the Air, the X300 has three U.S.B. ports, as well as a headphone jack, Ethernet jack and an optional slim DVD burner. There is also built-in Wi-Fi and an integrated camera and microphone. In its lightest configuration, the X300 weighs 2.93 pounds and measures just 0.73 of an inch thick.

Next to the shiny MacBook Air, the X300 looks as if it is wearing a black wool suit at a costume ball. But plenty of road warriors might just like it that way. JOHN BIGGS

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Sistem Monitoring Material Clogging Pada Reaktor Low Linier Density Polyethylene dengan Radiasi Gamma

Has been construted the clogging monitor system of LLDPE (Low linier density polyehilene) use absorption gamma radiation methode. The gamma source Cs137 put in the centre of the process LLDPE Reactor and the detectors ststem (12 detectors) instals serounding outside of the LLDPE Reactor process. The detectors system conect to data acqusition and computer system, measuring result of computer is two dimention topografi profile. The advantage of this system is non contact and on line clogging mesurement reactor process. So it can prediction of clogging before.
Rony Djokorayono

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The Advantages of Closing Few Doors (2)

“We may work more hours at our jobs,” Dr. Ariely writes in his book, “without realizing that the childhood of our sons and daughters is slipping away. Sometimes these doors close too slowly for us to see them vanishing.”

Dr. Ariely, one of the most prolific authors in his field, does not pretend that he is above this problem himself. When he was trying to decide between job offers from M.I.T. and Stanford, he recalls, within a week or two it was clear that he and his family would be more or less equally happy in either place. But he dragged out the process for months because he became so obsessed with weighing the options.

“I’m just as workaholic and prone to errors as anyone else,” he says.. “I have way too many projects, and it would probably be better for me and the academic community if I focused my efforts. But every time I have an idea or someone offers me a chance to collaborate, I hate to give it up.”

So what can be done? One answer, Dr. Ariely said, is to develop more social checks on overbooking. He points to marriage as an example: “In marriage, we create a situation where we promise ourselves not to keep options open. We close doors and announce to others we’ve closed doors.”

Or we can just try to do it on our own. Since conducting the door experiments, Dr. Ariely says, he has made a conscious effort to cancel projects and give away his ideas to colleagues. He urges the rest of us to resign from committees, prune holiday card lists, rethink hobbies and remember the lessons of door closers like Xiang Yu.

If the general’s tactics seem too crude, Dr. Ariely recommends another role model, Rhett Butler, for his supreme moment of unpredictable rationality at the end of his marriage. Scarlett, like the rest of us, can’t bear the pain of giving up an option, but Rhett recognizes the marriage’s futility and closes the door with astonishing elan. Frankly, he doesn’t give a damn.

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The Advantages of Closing a Few Doors (1)

The next time you’re juggling options — which friend to see, which house to buy, which career to pursue — try asking yourself this question: What would Xiang Yu do?

Xiang Yu was a Chinese general in the third century B.C. who took his troops across the Yangtze River into enemy territory and performed an experiment in decision making. He crushed his troops’ cooking pots and burned their ships.

He explained this was to focus them on moving forward — a motivational speech that was not appreciated by many of the soldiers watching their retreat option go up in flames. But General Xiang Yu would be vindicated, both on the battlefield and in the annals of social science research.

He is one of the role models in Dan Ariely’s new book, “Predictably Irrational,” an entertaining look at human foibles like the penchant for keeping too many options open. General Xiang Yu was a rare exception to the norm, a warrior who conquered by being unpredictably rational.

Most people can’t make such a painful choice, not even the students at a bastion of rationality like the Massachusetts Institute of Technology, where Dr. Ariely is a professor of behavioral economics. In a series of experiments, hundreds of students could not bear to let their options vanish, even though it was obviously a dumb strategy (and they weren’t even asked to burn anything).

The experiments involved a game that eliminated the excuses we usually have for refusing to let go. In the real world, we can always tell ourselves that it’s good to keep options open.

You don’t even know how a camera’s burst-mode flash works, but you persuade yourself to pay for the extra feature just in case. You no longer have anything in common with someone who keeps calling you, but you hate to just zap the relationship.

Your child is exhausted from after-school soccer, ballet and Chinese lessons, but you won’t let her drop the piano lessons. They could come in handy! And who knows? Maybe they will.

In the M.I.T. experiments, the students should have known better. They played a computer game that paid real cash to look for money behind three doors on the screen. (You can play it yourself, without pay, at tierneylab.blogs.nytimes.com.) After they opened a door by clicking on it, each subsequent click earned a little money, with the sum varying each time.

As each player went through the 100 allotted clicks, he could switch rooms to search for higher payoffs, but each switch used up a click to open the new door. The best strategy was to quickly check out the three rooms and settle in the one with the highest rewards.

Even after students got the hang of the game by practicing it, they were flummoxed when a new visual feature was introduced. If they stayed out of any room, its door would start shrinking and eventually disappear.

They should have ignored those disappearing doors, but the students couldn’t. They wasted so many clicks rushing back to reopen doors that their earnings dropped 15 percent. Even when the penalties for switching grew stiffer — besides losing a click, the players had to pay a cash fee — the students kept losing money by frantically keeping all their doors open.

Why were they so attached to those doors? The players, like the parents of that overscheduled piano student, would probably say they were just trying to keep future options open. But that’s not the real reason, according to Dr. Ariely and his collaborator in the experiments, Jiwoong Shin, an economist who is now at Yale.

They plumbed the players’ motivations by introducing yet another twist. This time, even if a door vanished from the screen, players could make it reappear whenever they wanted. But even when they knew it would not cost anything to make the door reappear, they still kept frantically trying to prevent doors from vanishing.

Apparently they did not care so much about maintaining flexibility in the future. What really motivated them was the desire to avoid the immediate pain of watching a door close.

“Closing a door on an option is experienced as a loss, and people are willing to pay a price to avoid the emotion of loss,” Dr. Ariely says. In the experiment, the price was easy to measure in lost cash. In life, the costs are less obvious — wasted time, missed opportunities. If you are afraid to drop any project at the office, you pay for it at home
By JOHN TIERNEY

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The Advantages of Closing a Few Doors (1)

The next time you’re juggling options — which friend to see, which house to buy, which career to pursue — try asking yourself this question: What would Xiang Yu do?

Xiang Yu was a Chinese general in the third century B.C. who took his troops across the Yangtze River into enemy territory and performed an experiment in decision making. He crushed his troops’ cooking pots and burned their ships.

He explained this was to focus them on moving forward — a motivational speech that was not appreciated by many of the soldiers watching their retreat option go up in flames. But General Xiang Yu would be vindicated, both on the battlefield and in the annals of social science research.

He is one of the role models in Dan Ariely’s new book, “Predictably Irrational,” an entertaining look at human foibles like the penchant for keeping too many options open. General Xiang Yu was a rare exception to the norm, a warrior who conquered by being unpredictably rational.

Most people can’t make such a painful choice, not even the students at a bastion of rationality like the Massachusetts Institute of Technology, where Dr. Ariely is a professor of behavioral economics. In a series of experiments, hundreds of students could not bear to let their options vanish, even though it was obviously a dumb strategy (and they weren’t even asked to burn anything).

The experiments involved a game that eliminated the excuses we usually have for refusing to let go. In the real world, we can always tell ourselves that it’s good to keep options open.

You don’t even know how a camera’s burst-mode flash works, but you persuade yourself to pay for the extra feature just in case. You no longer have anything in common with someone who keeps calling you, but you hate to just zap the relationship.

Your child is exhausted from after-school soccer, ballet and Chinese lessons, but you won’t let her drop the piano lessons. They could come in handy! And who knows? Maybe they will.

In the M.I.T. experiments, the students should have known better. They played a computer game that paid real cash to look for money behind three doors on the screen. (You can play it yourself, without pay, at tierneylab.blogs.nytimes.com.) After they opened a door by clicking on it, each subsequent click earned a little money, with the sum varying each time.

As each player went through the 100 allotted clicks, he could switch rooms to search for higher payoffs, but each switch used up a click to open the new door. The best strategy was to quickly check out the three rooms and settle in the one with the highest rewards.

Even after students got the hang of the game by practicing it, they were flummoxed when a new visual feature was introduced. If they stayed out of any room, its door would start shrinking and eventually disappear.

They should have ignored those disappearing doors, but the students couldn’t. They wasted so many clicks rushing back to reopen doors that their earnings dropped 15 percent. Even when the penalties for switching grew stiffer — besides losing a click, the players had to pay a cash fee — the students kept losing money by frantically keeping all their doors open.

Why were they so attached to those doors? The players, like the parents of that overscheduled piano student, would probably say they were just trying to keep future options open. But that’s not the real reason, according to Dr. Ariely and his collaborator in the experiments, Jiwoong Shin, an economist who is now at Yale.

They plumbed the players’ motivations by introducing yet another twist. This time, even if a door vanished from the screen, players could make it reappear whenever they wanted. But even when they knew it would not cost anything to make the door reappear, they still kept frantically trying to prevent doors from vanishing.

Apparently they did not care so much about maintaining flexibility in the future. What really motivated them was the desire to avoid the immediate pain of watching a door close.

“Closing a door on an option is experienced as a loss, and people are willing to pay a price to avoid the emotion of loss,” Dr. Ariely says. In the experiment, the price was easy to measure in lost cash. In life, the costs are less obvious — wasted time, missed opportunities. If you are afraid to drop any project at the office, you pay for it at home
By JOHN TIERNEY

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Centuries-old Maya Blue Mystery Finally Solved

ScienceDaily (Feb. 28, 2008) — Anthropologists from Wheaton College (Illinois) and The Field Museum have discovered how the ancient Maya produced an unusual and widely studied blue pigment that was used in offerings, pottery, murals and other contexts across Mesoamerica from about A.D. 300 to 1500.
First identified in 1931, this blue pigment (known as Maya Blue) has puzzled archaeologists, chemists and material scientists for years because of its unusual chemical stability, composition and persistent color in one of the world's harshest climates.
The anthropologists solved another old mystery, namely the presence of a 14-foot layer of blue precipitate found at the bottom of the Sacred Cenote (a natural well) at Chichén Itzá. This remarkably thick blue layer was discovered at the beginning of the 20th century when
the well was dredged.
Chichén Itzá, one of the Seven Wonders of the Ancient World, is an important pre-Columbian archeological site built by the Maya who lived on what is now the Yucatán Peninsula of Mexico.
The findings from this research will be published online Feb. 26, 2008, by the prestigious British journal Antiquity and will appear in the print version of the quarterly journal to be released in early March.
According to 16th Century textual accounts, blue was the color of sacrifice for the ancient Maya. They painted human beings blue before thrusting them backwards on an altar (see below for image) and cutting their beating heart from their bodies. Human sacrifices were also painted blue before they were thrown into the Sacred Cenote at Chichén Itzá. In addition, blue was used on murals, pottery, copal incense, rubber, wood and other items thrown into the well.
The new research concludes that the sacrificial blue paint found at this site was not just any pigment. Instead, it was the renowned Maya Blue -- an important, vivid, virtually indestructible pigment.
Maya Blue is resistant to age, acid, weathering, biodegradation and even modern chemical solvents. It has been called "one of the great technological and artistic achievements of Mesoamerica."
Scientists have long known that the remarkably stable Maya Blue results from a unique chemical bond between indigo and palygorskite, an unusual clay mineral that, unlike most clay minerals, has long interior channels. Several studies have found that Maya Blue can be created by heating a mixture of palygorskite with a small amount of indigo, but they have not been able to discover how the ancient Maya themselves actually produced the pigment.
The new research shows that at Chichén Itzá the creation of Maya Blue was actually a part of the performance of rituals that took place alongside the Sacred Cenote. Specifically, the indigo and palygorskite were fused together with heat by burning a mixture of copal incense, palygorskite and probably the leaves of the indigo plant. Then the sacrifices were painted blue and thrown into the Sacred Cenote.
"These sacrifices were aimed at placating the rain god Chaak," said Dean E. Arnold, Professor of Anthropology at Wheaton College, Research Associate at The Field Museum and lead author of the study. "The ritual combination of these three materials, each of which was used for healing, had great symbolic value and ritualistic significance.
"The Maya used indigo, copal incense and palygorskite for medicinal purposes," Arnold continued. "So, what we have here are three healing elements that were combined with fire during the ritual at the edge of the Sacred Cenote. The result created Maya Blue, symbolic of the healing power of water in an agricultural community."
Rain was critical to the ancient Maya of northern Yucatan. From January through mid-May there is little rain -- so little that the dry season could be described as a seasonal drought. "The offering of three healing elements thus fed Chaak and symbolically brought him into the ritual in the form a bright blue color that hopefully would bring rainfall and allow the corn to grow again," Arnold said.
Museum collections play key role
One of the keys to solving the mystery of Maya Blue production was a three-footed pottery bowl (Field Museum catalog number 1969.189262; see below for reference to image) containing rarely preserved copal dredged from the Sacred Cenote at Chichén Itzá in 1904 and traded to The Field Museum in the 1930s. Preserved in the copal were fragments of a white substance and blue pigment. Using The Field Museum's scanning electron microscope, the authors studied these inclusions and found signatures for palygorskite and indigo. From this they concluded that the Maya produced Maya Blue as part of their sacrificial ceremonies.
"This study documents the analytical value of museum collections for resolving long-standing research questions," said Gary Feinman, Curator of Anthropology at The Field Museum and co-author of the study.
But other knowledge was necessary to understand the significance of the bowl and the hardened copal it contains.
"This study required documentary, ethnographic and experimental research to establish the full context and use of the artifacts," Feinman said. "Our work emphasizes the potential rewards of scientific work on old museum collections. It also shows that scientific analysis is necessary but not sufficient for understanding museum objects."
It is this broad knowledge coupled with the scientific analysis that has enabled the scientists to finally -- after more than 100 years -- explain the thick layer of blue precipitate at the bottom of the Sacred Cenote at Chichén Itzá.
Already knowing that Maya Blue was central to Maya ritualistic sacrifices together with discovering that the pigment was produced right beside the Cenote solved the mystery of the 14-foot layer of blue precipitate: So many sacrifices -- from pots to more than 100 human beings -- were thrown into the Sacred Cenote that ultimately a layer of the pigment washed off the sacrifices and settled at the bottom of the well. (Although fully formed Maya Blue is extremely durable, it can be washed off with water, especially if there is no binder to help it adhere to the object on which it is placed.)
Other objects in The Field Museum's collections may reveal more information about Maya Blue, the scientists said. For example, identification of the plant materials on the bottom of the copal incense in other bowls dredged from the Sacred Cenote at Chichén Itzá could reveal which portions of the indigo plant were used to make Maya Blue.
"The Field Museum's collection was critical in solving this mystery," Arnold concluded. "This bowl has been in the collection for 75 years yet only now have we been able to use it in discovering the ancient Maya technology of making Maya Blue."
The other co-authors of this research are Jason Branden from Northwestern University, and Patrick Ryan Williams and J.P. Brown, both from The Field Museum.
by Field Museum

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Buried Seed Vault Opens in Arctic

UPDATED, 8:30 a.m.] After several years of planning and digging, the world has its first secure, deep-frozen repository for backup supplies of seeds from hundreds of thousands of plant varieties that underpin agriculture. The Svalbard Global Seed Vault was built into a frigid mountainside in Norway’s northernmost archipelago, deep in the Arctic. It had its ceremonial opening Tuesday morning in the frigid gloom of the Arctic winter. [UPDATE: Many readers wondered about whether it was too close to sea level. But, as I learned in my three Arctic trips, things up there are way more spread out than they appear. The tunnel entrance is 130 meters, or about 400 feet, above sea level. So all can rest easy on that front.]
There are something like 1,400 seed banks around the world, guarding samples of crop plants ranging from alfalfa to yams. But, as I wrote last year, this agricultural archive is eroding under forces including war, storms, scant money or bad management, particularly in the world’s poorest or
most turbulent places. A Fort Knox has been needed, many experts said. Now they have it.
Some advocates for strengthening the capacity of local communities to sustain their agricultural traditions and crop diversity on their own aren’t happy about this kind of centralized approach, though (more on this below).
No one questions the vulnerability of many of the world’s seed stores. Iraq’s bank of ancient wheat, barley and other crop strains in the town of Abu Ghraib — made infamous for other reasons — was looted during the war (mainly for the containers holding grain samples, not for the grain itself). An international rice repository in the Philippines was shredded by a typhoon.
The new repository is intended to be an insurance policy for individual countries and also for humanity more generally, should larger-scale disaster strike (anything from pestilence to an asteroid impact).
The Norwegian government put up more than $7 million for construction. The Bill and Melinda Gates Foundation is providing money to help developing countries package and ship seed samples, as part of a broader $30-million project to protect the genetic diversity of the world’s main food crops.
The ongoing operation of the seed vault will be paid for through the Global Crop Diversity Trust, which is maintained by contributions from countries, international agencies, and foundations.
A secure supply of thousands of varieties of keystone crops like rice and wheat will be ever more important, experts say, as populations grow, climate changes, and people keep moving species around the global, both intentionally and accidentally.

Grain.org, a group based in Spain focused on strengthening regional agriculture, was one of the few entities criticizing the focus on the seed vault. The group worries that such moves take away intellectual property rights to crop varieties from the farming communities that developed them and provide a false sense of confidence that safe storage, on its own, can sustain agricultural diversity.
As the group noted in a news release today (hat tip to Danny Bloom):
Thousands of accessions have died in storage, as many have been rendered useless for lack of basic information about the seeds, and countless others have lost their unique characteristics or have been genetically contaminated during periodic grow-outs. This has happened throughout the ex situ system, not just in gene banks of developing countries. So the issue is not about being for or against gene banks, it is about the sole reliance on one conservation strategy that, in itself, has a lot of inherent problems.
The deeper problem with the single focus on ex situ seed storage, that the Svalbard Vault reinforces, is that it is fundamentally unjust. It takes seeds of unique plant varieties away from the farmers and communities who originally created, selected, protected and shared those seeds and makes them inaccessible to them. The logic is that as people’s traditional varieties get replaced by newer ones from research labs -– seeds that are supposed to provide higher yields to feed a growing population – the old ones have to be put away as “raw material” for future plant breeding. This system forgets that farmers are the world’s original, and ongoing, plant breeders.
It’s a noteworthy point. The groups funding the seed vault, including the Gates Foundation, say they are also pouring money into creating databases and other mechanisms for maintaining poor countries’ access to the full array of crop strains. But what about the farmers in the field?
In a world tending toward monoculture, how much of this intergovernmental work helps sustain farming diversity, as opposed to museum-style genetic diversity? Do farmers matter?
By Andrew C. Revkin

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XM Satellite Quarterly Loss Narrows

NEW YORK (Reuters) - XM Satellite Radio Holdings Inc, which is planning to merge with rival Sirius Satellite Radio Inc, Thursday said its quarterly loss narrowed as it added more subscribers to its pay radio service.
The leading satellite radio provider, whose programming includes Oprah Winfrey and Major League Baseball, posted a fourth-quarter loss of $238.8 million, or 78 cents a share, compared with a loss of $263.2 million, or 90 cents a share, a year earlier.
The loss includes 25 cents a share in merger and settlement related charges, XM said.
Analysts had expected a loss of 63 cents a share, according to Reuters Estimates. It was not immediately clear if the figures were comparable.
Revenue rose 20 percent to $308 million.
XM said it added 1.13 million subscribers in the period, and 460,000 after accounting for disconnections. In all, XM ended with 9.03 million subscribers.
By REUTERS

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Electrodynamics via Special Relativity and Quantum Mechanics

An investigation to unify methodologies and laws of various branches of physics leads to deduce electrodynamics laws contained in Lorentz-Maxwell equations in the context of special relativity. Starting from an application of the Dirac quantum conditions. One could identify a minimum substitution which upgrades the kinetic momentum into a general one for a particle moving in a velocity dependent external potential field. This substitution introduces a vector potential A which together with a velocity independent potential governs the dynamics of the particle through a combined interaction with both fields resulting in a Lorentz ponderomotive force law and gauge invariant potential fields. Implementation of variational principle on combined action integrals belonging to the fields and its interaction with the particle leads to source dependent field equations requations required to reproduce the complete set of Max-well equations. As a byproduct, one could describe fictional forces observed in non inertia' system of references as a manifestation of a general Lorentz force arising from minimal substitution; the resulting vector and scalar potential could account for the fictional Coriolis and centrifugal forces.
Key-words: Electrodynamics, special relativity, quantum mechanics
Muslim dan Zahara M.

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MECHANICAL PROPERTIES OF CONCRETE

Concrete building safety of fire is better than other building materials such as wood, plastic, and steel, because it is incombustible and emitting no toxic fumes during high temperature exposure. However, the deterioration of concrete because of high temperature exposure will reduce the concrete strength. Mechanical properties such as compressive strength and modulus of elasticity are absolutely corrupted during and after the heating process. This paper aims to investigate mechanical properties of concrete (especially compressive strength and modulus of elasticity) with various water-cement ratio after concrete suffered by high temperature exposure of 500oC. This research conducted experimental method and analytical method. The experimental method produced concrete specimens with specifications: (1) specimen’s dimension is 150 mm x 300 mm concrete cylinder; (2) compressive strength design, f’c = 22.5 MPa; (3) water-cement ratio variation =0.4, 0.5, and 0.6. All specimens are cured in water for 28 days. Some specimens were heated for 1 hour with high temperature of 500oC in huge furnace, and the others that become specimen-control were unheated. All specimens, heated and unheated, were evaluated by compressive test. Experimental data was analyzed to get compressive strength and modulus of elasticity values. The analytical method aims to calculate modulus of elasticity of concrete from some codes and to verify the experimental results. The modulus elasticity of concrete is calculated by 3 expressions: (1) SNI 03-2847-1992 (which is the same as ACI 318-99 section 8.5.1), (2) ACI 318-95 section 8.5.1, and (3) CEB-FIP Model Code 1990 Section 2.1.4.2. The experimental and analytical results found that: (1) The unheated specimens with water-cement ratio of 0.4 have the greatest value of compressive strength, while the unheated specimens with watercement ratio of 0.5 gets the greatest value of modulus of elasticity. The greatest value of compressive strength of heated specimens provided by specimens with water-cement ratio of 0.5, while the heated specimens with water-cement ratio of 0.4 gets the greatest value of modulus of elasticity, (2) All heated specimens lose their strength at high temperature of 500oC, (3) The analytical result shows that modulus of elasticity calculated by expression III has greater values compares to expression I and II, but there is only little difference value among those expressions, and (4)The variation of water-cement ratio of 0.5 becomes the optimum value. Keywords : Concrete, Compressive strength, Modulus of elasticity, Water-cement ratio, High temperature.

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EU unveils `most ambitious' climate goals

The European Commission (EC) presented "the most ambitious policy ever" to fight climate change on Wednesday (Thursday morning in Jakarta), challenging the world to follow Europe's lead in cutting greenhouse gas emissions.
The European Union's executive branch proposed the 27-nation bloc reduce emissions by at least 20 percent by 2020 compared to 1990 levels, with the possibility of going to 30 percent if other developed countries join in.
The targets are part of new proposals for a broad European Union (EU) energy policy that aims to boost production of renewable fuels, cut energy consumption, and reduce the dominance of bvg utility companies over EU gas and electricity markets.
With oil imports hit by the latest dispute involving Russia, the Commission's vision for an EU-wide energy policy also seeks to ease dependence on foreign suppliers and push. the bloc to speak with one voice on the world stage.
But Brussels made fighting global warming the core of its strategy.
"If this was adopted it would be by far the most ambitious policy ever — not only in Europe but the world — against climate change," European Commission President Jose Manuel Barroso told a news conference.
The plan needs to be approved by EU governments and the European Parliament.
The new goal goes beyond an existing target for an eight percent cut in emissions from 1990 levels in the 2008-2012 period adopted by the 15 members of the EU before its 2004 enlargement, which several countries are struggling to meet.
The EU renewed its calls on the United States — the world's biggest polluter — and other major economies to drop their opposition to binding targets for emissions cuts.
"We need the United States with us," said Barroso, who met U.S. President George W Bush this week. "I personally believe the United States will change and they will be much more ambitious in the future when it comes to climate change."
Germany, holder of the bloc's rotating presidency, said the policy showed the EU's leadership on climate change.
"I think it is ambitious but realistic," said Claude Mandil, executive director of the International Energy Agency in Paris.
But environmentalists said the plan fell short.
"Scientific findings show that it simply won't be enough for the EU to only reduce C02 emissions by 20 percent by 2020 if we want to avoid catastrophic climate change," said Jan Kowalzig, climate campaigner at Friends of the Earth Europe.
EU business lobby UNICE protested the target was too high and said European business would suffer if other countries around the world do not agree to cuts.
Energy has been at the heart of the EU since it was born as the European Coal and Steel Community half a century ago but policv remains largely in the hands of national governments.
This week's dispute between Russia and Belarus, which has hit oil exports to several EU nations, has highlighted the bloc's vulnerability to foreign producers of fuel.
The Commission's report said plans to shut reactors will make cutting emissions harder and it encouraged countries phasing out nuclear power, such as Germany, to replace it with non-polluting sources.
The Commission proposed that renewable energy sources, such as wind, make up 20 percent of the EU's energy mix by 2020, up from a non-binding goal of 12 percent by 2010 which the bloc is likely to miss.
The new plan also says biofuels should account for a minimum of 10 percent of fuel used by vehicles by 2020.
On one of the most politically sensitive items, Barroso said Brussels favored splitting up the generation and distribution businesses of power companies to tackle what his regulators said were "serious competition problems" in the sector.
But Germany and France oppose that idea and the Commission offered a second
option of utilities handing over management of grid businesses while retaining ownership. That option would mean more intrusive regulation, one EU official said.
French power giant EDF said full separation of generation and distribution was unnecessary. Germany's E.ON and RWE also rejected the proposals.
French Industry Minister Francois Loos, referring to the ownership proposals, said "there are subjects on which we will make ourselves heard by the Commission."

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Energy policy to face crisis a must for RI: Analysts

Jakarta: Indonesia needs an immediate energy diversification policy, including nuclear power, to provide the country with guidelines for facing the world energy crisis, said energy and environmental analysts here Monday.
World oil prices reached almost US$100 barrel in November, pushing it beyond poor countries' purchasing ability, said author Agus Mustofa in his book Nuclear Power in Indonesia under the World Energy War Scheme.
Agus led an energy-focused discussion Monday with Emil Salim, former Indonesian environment minister; Kurtubi, an energy analyst from the University of Indonesia; and Riswanto, a social analyst from the Indonesian Institute of Sciences.
Agus said nuclear power was the most feasible and rational alternative energy source available to Indonesia today.
He said during the discussion the country needed nuclear power to stop its dependence on fossil energy because it was predicted the country would run out of its fossil fuel reserves in 2020.
"In fact, Indonesia has already become a net oil importing country since 2005, and its need for oil is continuously growing," Agus said.
"Moreover, fossil energy is continuously causing great environmental devastation, especially global warming.
"Japan currently uses nuclear energy to provide around 30 percent of its need for electricity and plans to expand that to reach 40 percent in 2025.
"Nuclear energy also provides almost 80 percent of France's electricity needs," he said.
"In Asia, countries like China, South Korea, Taiwan and India have already begun their nuclear power energy source."
Although Agus said he had no doubt about Indonesia's need to end its 95 percent dependency on fossil energy, he said most Indonesians' perceptions of nuclear power was still very negative.
"In Indonesia, nuclear power is always associated with radiation, toxic waste and disasters," he said.
Emil Salim said for Indonesia to diversify energy sources, the most important step was to ensure a balanced market place for non-renewable and renewable energy sources to compete.
"The government provides around Rp 70 trillion (US$7.4 billion) to subsidize oil energy," Emil said.
"How can renewable energy development occur in Indonesia.
"The government needs to fix this," he said.
With regard to risks and concerns associated with the development of nuclear energy for the archipelago, Emil said, "The government needs to immediately respond to the people's anxiety toward nuclear energy by allocating risk liability in its plan to build a nuclear reactor".
"Hopefully that (will) assure people that any accidents have already been anticipated, so nothing like the Lapindo mud disaster in East Java will happen.
"People need to be assured that the government is ready for any disaster possibility," Emil said.
"Don't just preach about how safe a nuclear plant is.
"If the government is very sure that there will be no nuclear-related accident, it must guarantee extensive insurance coverage for people living near the planned nuclear plant; Rp 1 billion for each family, if necessary."
Kurtubi said the government must overcome the psychological and political obstacles that had deterred the development of nuclear energy in Indonesia.
"The government must assure the people they have studied and learned from the collective experience of nuclear energy-using countries in minimizing the possibility of accidents since the 1950s," Kurtubi said.

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A Fundamental Integral on The Real Line

In the process of studying theory of integrals, we observe that are some intrinsic properties that they have in common. Those properties form a system of sets. The fact leads us to define a system of sets, which will be called a system of fundamental sets which has to possess certain properties. On this system, we further construct some concepts in calculus and define an integral which we call a fundamental integral. Also, we investigate its properties.
Soeparna Darmawijaya

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Riemann Type Definition of A Generalized Form of Henstock Integral

An important problem in any theory of integral is to find a constructive definition for the integral if the only available definition is a descriptive one. The main result of a research to find a constructive definition for a generalized Henstock integral which includes the Kubota integral as a special case is presented.
Key-words: Riemann integral, Kubota-AD integral, Henstock Integral

Bambang Soedijono

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Study of X-ray Diffraction Method for Detecting Crystallinity Change in Clays due to Thermal and Activation Process

The effects of thermal and activation process on crystalline structure of clays from Boyolali and Riau were investigated using an X-ray diffraction method. The towo treatments are expected to increase the crystallinity and stability of the crystal structure thereby improving the activity of the clays as absorbent cataysts and ion exchangers. the X-ray diffractograms showed that the Boyolali's clay is monomorilonit and Riau's clay is kaoline. Heating from 600 to 1000drajat C caused a damage to the monmorilonit crystal structure the decrease in crystallinity was proportional to the temperature increase. Similarly kaolinic crystallinity was destroyed at temperature higher than 600drajat C. Activation increased the crystallinity of the monmorilonit, but caused destruction to kaolinic crystal. Hence, the two treatments have not brought appropriate conditions for improving the stability and crystallinity of the clays which requires futher investigation.
Key words: X-ray diffraction, clays, catalysts
Endang Tri Wahyuni

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Mechanical properties of concretewith various water-cement ratioafter high temperature exposure

Concrete building safety of fire is better than other building materials such as wood, plastic, and steel,because it is incombustible and emitting no toxic fumes during high temperature exposure. However,the deterioration of concrete because of high temperature exposure will reduce the concrete strength. Mechanical properties such as compressive strength and modulus of elasticity are absolutely corruptedduring and after the heating process. This paper aims to investigate mechanical properties of concrete(especially compressive strength and modulus of elasticity) with various water-cement ratio afterconcrete suffered by high temperature exposure of 500oC.This research conducted experimental method and analytical method. The experimental methodproduced concrete specimens with specifications: (1) specimen’s dimension is 150 mm x 300 mmconcrete cylinder; (2) compressive strength design, f’c = 22.5 MPa; (3) water-cement ratio variation =0.4, 0.5, and 0.6. All specimens are cured in water for 28 days. Some specimens were heated for 1hour with high temperature of 500oC in huge furnace, and the others that become specimen-controlwere unheated. All specimens, heated and unheated, were evaluated by compressive test.Experimental data was analyzed to get compressive strength and modulus of elasticity values. Theanalytical method aims to calculate modulus of elasticity of concrete from some codes and to verifythe experimental results. The modulus elasticity of concrete is calculated by 3 expressions: (1) SNI03-2847-1992 (which is the same as ACI 318-99 section 8.5.1), (2) ACI 318-95 section 8.5.1, and (3)CEB-FIP Model Code 1990 Section 2.1.4.2.The experimental and analytical results found that: (1) The unheated specimens with water-cementratio of 0.4 have the greatest value of compressive strength, while the unheated specimens with watercementratio of 0.5 gets the greatest value of modulus of elasticity. The greatest value of compressivestrength of heated specimens provided by specimens with water-cement ratio of 0.5, while the heatedspecimens with water-cement ratio of 0.4 gets the greatest value of modulus of elasticity, (2) Allheated specimens lose their strength at high temperature of 500oC, (3) The analytical result shows thatmodulus of elasticity calculated by expression III has greater values compares to expression I and II,but there is only little difference value among those expressions, and (4)The variation of water-cementratio of 0.5 becomes the optimum value. Keywords : Concrete, Compressive strength, Modulus of elasticity, Water-cement ratio,High temperature. M.I. Retno Susilorini[1], Budi Eko Afrianto[2], Ary Suryo Wibowo[2]

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Is nuclear energy safe enough for Indonesia?

Fifty-three years have passed since the operation of the first nuclear power plant in 1954. Nuclear energy now supplies 16 percent of all electricity generated in the world. This percentage has been roughly stable since the Chernobyl accident in 1986, indicating that nuclear power has grown at the same rate as total global electricity. Twenty-six reactors are now at different stages of construction in 11 countries, most of them in Asia. Nuclear power plants are most attractive where energy demand growth is rapid, energy supply security is a priority, alternative resources are scarce, or reducing air pollution and GHG emissions is mandated. Nineteen out of 26 new plants will be located either in China, the Republic of Korea, Japan or India, where those factors are most urgent. For similar reasons, Indonesia, Vietnam, Malaysia and Thailand recently announced their intentions to go nuclear. This raises the question of safety for many observers, especially after the recent quake struck nuclear plants in Niigata, Japan. Is there some system to ensure that they all live up to a common, satisfactory level of safety? To answer these, one can look at the actions taken by the nuclear community after the Chernobyl accident in 1986. The following measures have been enforced worldwide to ensure safety. First, the application of strict regulations and oversights at internal, national and international level. Second, the selection of capable, regularly retrained and certified operators. Third, the use of inherently safe and proven nuclear power plants with defense-in-depth safety. At the international level, a global safety regime was instituted to promote a common level of safety. This "regime" is based on binding international conventions, accepted safety standards and an extensive system of peer reviews. Two conventions -- one on the Early Notification of a Nuclear Accident and a second on Assistance in the Case of a Nuclear Accident or Radiological Emergency -- were developed just a few months after the Chernobyl accident. A Convention on Nuclear Safety was developed later, requiring the parties to report every three years on the safety status of their nuclear power plants according to detailed guidelines; to identify any known deficiencies; and to take the necessary actions to eliminate them. These reports are critically reviewed among the parties and general recommendations are derived at a periodic review meeting. Indonesia has become a party to all these conventions, in addition to the NPT and the Comprehensive Safeguard Agreement. And indeed, the International Atomic Energy Agency (IAEA) has commended Indonesia on its compliance with the international agreements and conventions. At the national level, the Nuclear Regulatory Agency of Indonesia (Bapeten) was formed following the enactment of the Law on Nuclear Energy in 1997. The national nuclear watchdog was separated from promotional body (Batan) and other users to ensure the safety of nuclear installations. China and India started their nuclear programs worse off than Indonesia in terms of safety culture and discipline. Much like the Republic of Korea, which started its nuclear program in the 1970s when its nuclear human resources were less capable than those Indonesia had at that time. And now, as we face global warming and energy scarcity, our scientists and engineers are in a much better shape to continue with the idea. To answer the question on operators' discipline and ability, new standards for the certification and training of operators have been developed in recognition of the importance of the human factor in nuclear safety. This has resulted in a decreasing number of unwanted nuclear plant shutdowns in the past 17 years. And Indonesia, with over 42 years of experience in safely operating its research reactors in Bandung, Yogyakarta and Serpong, has shown that its carefully selected operators should have no problem adapting to this system. The IAEA reported in 2006 that it had trained more than 100 Indonesian nuclear scientists and engineers, some of whom have become trainers elsewhere in Asia. But what has been done to ensure the safety of nuclear plants in areas prone to earthquakes? The pursuit of a nuclear project is only authorized after detailed studies are conducted to identify all important potential physical threats to a site. These include maximum conditions such as rain, wind, flood levels, and extreme natural phenomena such as earthquakes, cyclones and tsunamis. When the nuclear plant is operated, site parameters are constantly monitored and automatic actions or safety procedures are in place to put the plant in a safe condition if any of the parameters are exceeded. The example of Taiwan and, more recently, Japan, as countries in the ring of fire with a high rate of earthquakes shows that with proper design, nuclear is the safest installation that exists. And Indonesia should not be an exception to it. Our Yogyakarta research reactor stood strong without any safety-related damage after it was hit by a 5.9-magnitude quake less than 30 kilometers from its epicenter in May 2006. However, the opposition of some of the local people in Cape Muria is an issue to be dealt with more seriously through a sound public information and education program established by Jakarta, since, according to our national law, nuclear issues must be dealt with by the central government. The first plant to be built in Cape Muria, Central Java, is a turnkey project, which could be owned and operated by foreign entities with minor local participation. In this way, the fear of corruption, which could compromise safety, can be minimized. The safety of a nuclear plant is not merely the business of an operator in one country. It is always under international scrutiny. Ferhat Aziz The writer is chief of the public relations,legal and cooperation bureau at the National Atomic Energy Agency (Batan) He can be reached at ferhat_az@yahoo.com.

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