Biofuels. Stir in the wrong direction?

Modern concepts consider biofuels as a green alternative to oil is less harmful to the environment. However, according to two scientists, as expressed by them in the pages of Bioenergetics (GCB Bioenergy), the benefits of biofuels are overrated.

According to researchers, estimates of greenhouse gas emissions from biofuel production and use do not include important information, which led to distortion.

Criticism of scientists focused on the model of life cycle analysis (Life Cycle Analysis, LCA) of biofuel production. Life cycle analysis is used to collect, collate and examine all the factors associated with the production, use and disposal of fuel or product. The authors concluded that the adopted model of LCA overestimates the positive aspects of biofuels compared to fossil fuels. The current assessment ignores CO2 emissions from vehicles running on biofuels.

Supporters of biofuels believe that this carbon should not be taken into account, because he collected plants grown for processing into fuel, and only returned to nature. Critics argue that in this case, biofuels do not reduce the level of carbon in the atmosphere. Biofuels can reduce carbon emissions only if it stimulates further growth of plants or uses for the production of biomass waste, which decompose with the release of carbon anyway.

Revaluation of bioenergy is further enhanced when one considers that there is still little attention paid to emissions of nitrogen fertilizer required for the cultivation of plant material. According to lead study author Dr. Keith Smith (Keith Smith) from the University of Edinburgh: "Emissions of N2O from the soil makes a huge contribution to global warming, which is associated with the culture of production. Each kilogram of N2O in the atmosphere has roughly the same effect as 300 kilograms of CO2 ».

Dr. Smith argues that current methods of life cycle analysis underestimated the percentage of nitrogen in fertilizers, which is actually released into the atmosphere as a greenhouse gas. The authors believe that the observed increase in atmospheric N2O shows that this percentage is actually almost twice that used in assessing the life cycle of biofuels, which significantly changes the results.

Given that the results of life cycle assessment is widely used, researchers Keith Smith and Timothy Sichinger (Timothy Searchinger) from Princeton University, concluded that the overall development of alternative fuels is moving in the wrong direction.

"The best opportunity to make a useful biofuel, is a waste treatment or focus on relatively moist, but very meager soil," - said Dr. Smith. "If bioenergy crops grown on degraded land will be allocated fewer greenhouse gases and more contact. Additional advantages of this approach - biofuels will not compete with food production, textiles and other goods. "

Solar energy will save the Earth

Stories about the coming end of the world this coming Friday, or, in extreme cases, the following Tuesday - no number. With an enviable constancy periodically on the horizon, there is a regular preacher calling to save souls in anticipation of the impending disaster. However, despite the fact that the accident did not happen, the real probability of collision with the Earth by a stray celestial body is real.

Thus, the scientists found in 2004 an asteroid Apophis in 2009, flew past Earth at a distance of 500,000 kilometers. According to the forecasts in the 2029-m celestial body weight 260 million tons may be close to our planet is much closer distance is reduced by an order of about 30-40 thousand miles. If this happens, then maybe an asteroid will sweep away a few satellites and affect the trajectory of the Earth. However, most adverse projections for 2036, when all there is some probability of a collision with Apophis.

The odds of collision is small, about 1:250,000. This figure was taken by researchers from the University of Strathclyde (Strathclyde), Glasgow, Scotland, Massimiliano Vasile (Massimiliano Vasile) and Christie Maddock (Christie Maddock). But what would you do if over time it became clear that a collision has yet to happen? Of course, a realistic scenario is the observation of the forthcoming apocalypse from under the bed is quite likely, but it can unconditionally accept perhaps that motley followers of "guru."

Some scientists consider it necessary to develop a global early warning system. Forewarned - forearmed. However, the extent of possible disaster is so great that the warning about it is not enough. The explosion of 510 megatons of power will inevitably lead to the deaths of millions of people to prevent it, except surveillance systems need a specific tool.

The work involves Maddock and Vasile, and practical advice. To fight Apophis, and perhaps with other such aliens, the researchers propose to use a technique known as laser ablation, a method of removing material by a laser pulse, as it qualifies Wikipedia.

In the outer scale of the proposal of scientists looks like this. The rays are directed several lasers on the surface of the asteroid, where, under the combined effect of radiation is the sublimation of a solid, its transition to a gaseous state bypassing the liquid. From the solid matter is a cloud of dust and small debris.

Laser ablation - not a new technique. However, so far as the source of the laser beam was considered a massive nuclear-powered power plant. Scientists at Strathclyde suggest instead to use compact and lightweight solar lasers.

The advantages of solar technology are obvious. They do not need a "change batteries", they do without the periodic supply of energy sources, mistakes and failures in one of the lasers will not lead to a denial of the whole system, problems with cooling small lasers are solved by cheaper methods.

In theory, lasers can work on very distant objects, if not turn them to dust in its entirety, giving them a boost, enough to change the trajectory.

Of course, it is only a theoretical idea. Scientists recognize that its implementation will require the "efficiency of the laser and solar cell at the upper limit of what is currently achievable in laboratory conditions," but the technology

As scientists, "Plant For" chemistry.

In the effort of scientists who are fighting for "greening" of chemistry, and are reflected 12 of the guidelines developed by chemists Paul Anastas and John Warner, who in the mid-1990s founded the movement for clean chemistry. Among those rules is this: it is better to prevent waste generation, than to remove them later. But if the waste can not be avoided, they must be non-toxic or minimally toxic, just as are the chemical products. Chemical reactions have to be energy efficient, for example, passing at room temperature without additional heating. And ideally, chemists need to use renewable energy sources.

Chemistry, of course, is hardly ecologically pure science, but researchers are working to make it safer for the planet. Here are a few examples of how chemists improve the level of environmental responsibility by improving the chemical processes used in the manufacture of drugs, plastics and other products.

Water, water everywhere

When the two chemicals react, they usually need the liquid medium. She speaks frequently toxic solvents. When the reaction is over, chemists have to either pour it, or try to recycle. Environmentally friendly alternative is the use of safe solvent - water.

Bruce Lipschutz University of California developed a tiny bubble-shaped particles (nanoparticles) that allow to carry out the reaction in water. Chemicals get into the particles, where the environment is great for interaction, and the result is a product. Due to the high concentration of the reaction, they can proceed at room temperature. Scientists do not have to activate the reaction heat, and it saves time and energy.

Call to the aid of microbes

Another way to make the reaction take place in a water-based, not solvent, is the use of microbes. Scientists are working on micro-organisms to produce useful molecules, as a rule, enzymes whose job is to carry out chemical reactions in solutions of water-based. Chemists can use microbes or simply their enzymes to accelerate chemical reactions in aqueous solution.

For example, Jay Kizling University of California, is developing microorganisms for the production of certain molecules. Several years ago, he placed more than a dozen genes in normal bacterium Escherichia coli and yeast fungus, which allowed the body to produce an antimalarial drug which is very expensive to produce by other means. A scientist examines a method for the production of drugs for HIV and environmentally friendly biofuels that can replace fuel-based minerals, such as gasoline.

A short synthesis of

Other scientists modify existing chemical compounds to make them environmentally friendly. For example, the laboratory synthesis of drug heparin, which prevents the formation of blood clots in people with heart disease usually takes 50 steps, and each of them generate waste.

Last year, Robert Lienhard from the Polytechnic Institute in upstate New York, USA, shortened the process to 12 steps. In the course of its implementation produce less waste, increases the yield of drugs that reduce the cost of production.

One common way to accelerate the chemical reaction is the use of a catalyst, usually metal, which facilitates the passage of the reaction. Shannon became the University of Wisconsin-Madison has developed a way to use the catalytic metal palladium and copper for the separation of hydrogen from a number of chemicals. When hydrogen combines with oxygen, the resulting product is water.

As a rule, chemists, carrying out large-scale reactions, limiting the access of oxygen, because it can cause explosions. The scientist also proposed a way to minimize this risk by conducting the reaction in the liquid flowing through the pipes instead of one large tank.