Ricerca e Scienze Tecnologiche

Laser fusion test results raise energy hopes

By Jason Palmer - Science and technology reporter, BBC News

A major hurdle to producing fusion energy using lasers has been swept aside, results in a new report show.
The controlled fusion of atoms - creating conditions like those in our Sun - has long been touted as a possible revolutionary energy source. However, there have been doubts about the use of powerful lasers for fusion energy because the "plasma" they create could interrupt the fusion. An article in Science showed the plasma is far less of a problem than expected. The report is based on the first experiments from the National Ignition Facility (Nif) in the US that used all 192 of its laser beams. Along the way, the experiments smashed the record for the highest energy from a laser - by a factor of 20.

Star power
Construction of the National Ignition Facility began at Lawrence Livermore National Laboratory in 1997, and was formally completed in May 2009. The goal, as its name implies, is to harness the power of the largest laser ever built to start "ignition" - effectively a carefully controlled thermonuclear explosion. INERTIAL CONFINEMENT FUSION 192 laser beams are focused through holes in a target container called a hohlraum Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes Lasers strike the hohlraum's walls, which in turn radiate X-rays X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees If the compression of the fuel is high enough and uniform enough, nuclear fusion can result Giant laser experiment powers up It is markedly different from current nuclear power, which operates through splitting atoms - fission - rather than squashing them together in fusion. Proving that such a lab-based fusion reaction can release more energy than is required to start it - rising above the so-called breakeven point - could herald a new era in large-scale energy production. In the approach Nif takes, called inertial confinement fusion, the target is a centimetre-scale cylinder of gold called a hohlraum. It contains a tiny pellet of fuel made from an isotope of hydrogen called deuterium. During 30 years of the laser fusion debate, one significant potential hurdle to the process has been the "plasma" that the lasers will create in the hohlraum. The fear has been that the plasma, a roiling soup of charged particles, would interrupt the target's ability to absorb the lasers' energy and funnel it uniformly into the fuel, compressing it and causing ignition. Siegfried Glenzer, the Nif plasma scientist, led a team to test that theory, smashing records along the way. "We hit it with 669 kilojoules - 20 times more than any previous laser facility," Nif's Siegfried Glenzer told BBC News. That isn't that much total energy; it's about enough to boil a one-litre kettle twice over. However, the beams delivered their energy in pulses lasting a little more than 10 billionths of a second. By way of comparison, if that power could be maintained, it would boil the contents of more than 50 Olympic-sized swimming pools in a second.

'Dramatic step'
Crucially, the recent experiments provided proof that the plasma did not reduce the hohlraum's ability to absorb the incident laser light; it absorbed about 95%. But more than that, Dr Glenzer's team discovered that the plasma can actually be carefully manipulated to increase the uniformity of the compression. The 130-tonne target chamber is kept under vacuum for the experiments "For the first time ever in the 50-year journey of laser fusion, these laser-plasma interactions have been shown to be less of a problem than predicted, not more," said Mike Dunne, director of the UK's Central Laser Facility and leader of the European laser fusion effort known as HiPER. "I can't overstate how dramatic a step that is," he told BBC News. "Many people a year ago were saying the project would be dead by now." Adding momentum to the ignition quest, Lawrence Livermore National Laboratory announced on Wednesday that, since the Science results were first obtained, the pulse energy record had been smashed again. They now report an energy of one megajoule on target - 50% higher than the amount reported in Science. The current calculations show that about 1.2 megajoules of energy will be enough for ignition, and currently Nif can run as high as 1.8 megajoules. Dr Glenzer said that experiments using slightly larger hohlraums with fusion-ready fuel pellets - including a mix of the hydrogen isotopes deuterium as well as tritium - should begin before May, slowly ramping up to the 1.2 megajoule mark. "The bottom line is that we can extrapolate those data to the experiments we are planning this year and the results show that we will be able to drive the capsule towards ignition," said Dr Glenzer. Before those experiments can even begin, however, the target chamber must be prepared with shields that can block the copious neutrons that a fusion reaction would produce. But Dr Glenzer is confident that with everything in place, ignition is on the horizon. He added, quite simply, "It's going to happen this year.".

INERTIAL CONFINEMENT FUSION
Giant laser experiment powers up

Volturno Morani - Generazione delle due Dimensioni - 90x110 1996 - smalto e vernice su tela





192 laser beams are focused through holes in a target container called a hohlraum. Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes. Lasers strike the hohlraum's walls, which in turn radiate X-rays. X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees. If the compression of the fuel is high enough and uniform enough, nuclear fusion can result.

Lose-Lose on Biofuels?

By Ted Gayer - THE AMERICANS

Forcing the market to produce large amounts of renewable fuel will harm consumers. Even though it reduces some emissions, it increases others.
The Environmental Protection Agency recently released its analysis of the renewable fuel standard enacted by the Energy Independence and Security Act of 2007. The standard requires 11.1 billion gallons of renewable fuel to displace petroleum fuel in 2009, ratcheting up each year until reaching 36.0 billion gallons of renewable fuels by 2022. There are separate volume requirements for advanced biofuels, cellulosic, and biodiesel.
Forcing the market to produce large amounts of renewable fuel will harm consumers in two ways: it will increase prices at the pump, because biofuels are more costly than gasoline, and it will drive up the price of food, because it diverts crops into fuel. The impact of food price inflation will weigh most heavily in developing countries where food purchases comprise larger shares of consumption. Food expenditures account for as much as 70 percent of household consumption among lower income groups in the developing world.
What can justify a policy that deliberately increases the price of food and fuel? Calling passage of the bill the “shot heard ‘round the world,” House Speaker Nancy Pelosi said it would improve the “health of our children.” But this is questionable at best. While the Environmental Protection Agency (EPA) analysis suggests that the switch toward renewables will decrease ammonia, carbon monoxide, and benzene, it also predicts “significant increases in ethanol and acetaldehyde emissions” and “more modest increases in nitrogen oxides, formaldehyde, particulate matter, hydrocarbons, acrolein, and sulfur dioxide.” Citing time constraints, the EPA did not do a full analysis of the net health effects of these emission profiles, but a reasonable assumption is that the detrimental health impacts from increased particulate matter will at least offset the health improvements from the predicted reductions in the other pollutants.
Supporters of the Energy Independence and Security Act of 2007 (EISA) also claimed that it will reduce greenhouse gases. Both Speaker Pelosi and then-President Bush said the bill will help reverse global warming. Indeed, much of the early enthusiasm for biofuels was based on the belief that their use would reduce greenhouse gases. It is true that burning biofuels results in less tailpipe emissions of greenhouse gases relative to burning petroleum. Yet this ignores the increase in emissions that results from the production of biofuels, especially the land use changes as farmers convert forest and grassland into cropland for biofuel production. An article published in Sciencemagazinein 2008 found that “corn-based ethanol nearly doubles greenhouse gas emissions over 30 years and increases greenhouse gases for 167 years.” Another article in Scienceconcluded that crop-based biofuels create a “biofuel carbon debt of 17 to 420 times more carbon dioxide than the greenhouse gas reductions that these biofuels would provide by displacing fossil fuels.”
Congress was aware of this concern. EISA requires that the mandated renewable fuels reduce greenhouse gases relative to petroleum, and it also requires emissions to be measured on a “lifecycle” basis that includes any “significant emissions from land use changes.” Under EISA, corn-based renewable fuel must result in a 20 percent reduction relative to petroleum; advanced (i.e., non–corn based) biofuels and biodiesel must result in a 50 percent reduction; and cellulosic biofuel must result in a 60 percent reduction. However, EISA gives the EPA discretion to lower these requirements by up to 10 percentage points.
This is where the EPA’s analysis is especially interesting. Given the results published in Science, many biofuels might not meet the greenhouse gas reduction required by EISA. This would largely gut the biofuel mandate. 
The EPA’s findings indeed show a substantial increase in greenhouse gas emissions stemming from the initial land use changes needed to meet the mandate. Only over a long time horizon do the relatively clean-burning fuels start to accrue reductions in greenhouse gases relative to petroleum.
The following figure from the EPA’s analysis shows the estimated emission profiles for corn-based biofuel, soy-based biodiesel, sugarcane ethanol, and switchgrass ethanol, stemming from the 2022 mandate of 36.0 billion gallons. There is an extremely large spike in emissions due to initial land-use changes, especially for corn-based ethanol and soy-based biodiesel. It takes more than 30 years for the emission reductions from these cleaner burning fuels to make up for the spike in emissions from the land-use changes. (Sugarcane and switchgrass biofuels fare much better.)

Opting not to substantially gut EISA’s biofuel mandate, the EPA evaluates these time profiles using either a very long time horizon of 100 years (so that there are more years in the future garnering emission reductions in order to dominate the first-year emissions spike), or a shorter time horizon (30 years) but with a zero discount rate (eliminating the typically assumed preference for current benefits relative to future benefits).
This figure clearly calls into question the merits of the renewable fuel standard. At a cost of higher fuel prices (the EPA predicts 2.7 to 10.9 cents more per gallon), higher food prices (the EPA predicts $10 more per person per year on food), increases in harmful local pollutants, and a considerable increase in short-term greenhouse gas emissions, the standard only starts paying climate-related dividends many years in the future.
There are three important concerns here: First, it is dangerously naïve to consider only direct emissions stemming from different fuels. As acknowledged in EISA, the full lifecycle emissions from a fuel include “all stages of fuel and feedstock production and distribution, from feedstock generation or extraction through the distribution and delivery and use of the finished fuel to the ultimate consumer.” A lifecycle analysis is extremely complex and the results are highly uncertain.
Second, a lifecycle analysis will present different emission time profiles for different fuels, leading to the tricky question of weighing the current emissions increase from land-use changes to the relative emission reductions in later years. The net results are highly contingent on the time horizon used for the evaluation, as well as the discount rate selected.
The third, and most important, lesson is an old one: reducing greenhouse gas emissions is best achieved from a comprehensive cap or tax that allows full flexibility across sectors or industries. Right now, Congress is considering the Waxman-Markey bill, which would establish an economy-wide cap on greenhouse gases. With a firm cap in place, a law that mandates different fuel mixes will increase the cap’s compliance costs and will not achieve any further reductions. Indeed, to the extent that land use changes are not captured by the cap, the biofuels mandate may actually lead to emission increases. Unfortunately, not only does the Waxman-Markey bill keep the biofuels mandate in place; it goes one step further by creating a renewable electricity standard that mandates different fuel types for electricity generation.
Ted Gayer is an associate professor at Georgetown University’s Public Policy Institute. From July 2007 to July 2008, he served as deputy assistant secretary of economic policy at the Treasury Department.
Image by Darren Wamboldt/Bergman Group.

“Las células madre embrionarias han fracasado”,
afirma Natalia López Moratalla
Catedrática de Bioquímica y Biología Molecular,
asegura que “la esperanza para los enfermos está en las células adultas”

 The vaccine, made by Acambis, should protect against all strains of influenza A - the cause of pandemics. Currently, winter flu jabs have to be regularly redesigned because the flu virus keeps changing.

 de Jorge Enrique Mújica

 La concesión del premio Nobel de la Paz al Panel Intergubernamental sobre Cambio Climático (IPCC por sus siglas en inglés) ha constituido el culmen del reconocimiento a una carrera ideológica de carácter planetario. El proceso se remonta a la Conferencia Mundial sobre medio ambiente realizada en Río de Janeiro en 1992 la cual tuvo continuidad en la Conferencia Mundial sobre el hábitat tenida en Estambul en 1996 y, dentro de poco tiempo, se verá reforzada por la Cumbre Mundial sobre el Cambio Climático que se realizará en Bali.

 Ben Osborne's image was captured during a three-week stake-out on location in the Chobe National Park. Speaking about his winning snap, Mr Osborne said: "I love the energy in this image. It has more to do with physics than biology."

Cambio radical... ¿seguro?

di e. n.

Nel rilevare l'importante ruolo del nucleare a favore dell'approvvigionamento energetico dell'UE e il suo basso impatto ambientale, il Parlamento chiede una riforma generalizzata del Trattato Euratom. Se la scelta nucleare spetta agli Stati membri, è necessario porre la sicurezza al centro delle attività Euratom e implicare il Parlamento nel processo decisionale. Occorre poi sviluppare la ricerca e la formazione, e aumentare gli investimenti per affrontare la concorrenza internazionale.

di Tonia Romano

La Recep, presieduta da Gabriella Cundari, Assessore regionale con delega all'Urbanistica, Politiche del Territorio, Edilizia Pubblica Abitativa, Accordi di Programma della Regione Campania,è un'organizzazione internazionale di tipo non governativo costituita da enti locali e regionali, sorta per favorire la conoscenza e l'applicazione della Convenzione Europea del Paesaggio.

By John Calfee  

(...continued) 

In the search for entirely new mecha­nisms, however, uncer­tainty abounds. For decades, research on the mechanism that would power Avastin was the lonely obsession of biologist and pediatric surgeon Judah Folkman at Children's Hospital in Boston.