Helicopter Could Be 'Scout' for Mars Rovers

Enter the Mars Helicopter, a proposed add-on to Mars rovers of the future that could potentially triple the distance these vehicles currently drive in a Martian day, and deliver a new level of visual information for choosing which sites to explore.

The helicopter would fly ahead of the rover almost every day, checking out various possible points of interest and helping engineers back on Earth plan the best driving route.

Scientists could also use the helicopter images to look for features for the rover to study in further detail. Another part of the helicopter's job would be to check out the best places for the rover to collect key samples and rocks for a cache, which a next-generation rover could pick up later.

The vehicle is envisioned to weigh 2.2 pounds (1 kilogram) and measure 3.6 feet (1.1 meters) across from the tip of one blade to the other. The prototype body looks like a medium-size cubic tissue box.

The current design is a proof-of-concept technology demonstration that has been tested at NASA's Jet Propulsion Laboratory, Pasadena, California.

Source: Nasa

Switching to vehicles powered by electricity from renewables could save lives - Video

Use of corn ethanol or electricity from coal worse than gasoline for public health

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. This finding comes from a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts, published Monday, Dec. 15, 2014, in the Proceedings of the National Academy of Sciences.

The study also shows that switching to vehicles powered by electricity made using natural gas yields large health benefits. Conversely, vehicles running on corn ethanol or vehicles powered by coal-based or "grid average" electricity are worse for health; switching from gasoline to those fuels would increase the number of resulting deaths due to air pollution by 80 percent or more.

“These findings demonstrate the importance of clean electricity, such as from natural gas or renewables, in substantially reducing the negative health impacts of transportation,” said Chris Tessum, co-author on the study and a researcher in the Department of Civil, Environmental, and Geo- Engineering in the University of Minnesota’s College of Science and Engineering.

The University of Minnesota team estimated how concentrations of two important pollutants—particulate matter and ground-level ozone—change as a result of using various options for powering vehicles. Air pollution is the largest environmental health hazard in the U.S., in total killing more than 100,000 people per year. Air pollution increases rates of heart attack, stroke, and respiratory disease.

The authors looked at liquid biofuels, diesel, compressed natural gas, and electricity from a range of conventional and renewable sources. Their analysis included not only the pollution from vehicles, but also emissions generated during production of the fuels or electricity that power them. With ethanol, for example, air pollution is released from tractors on farms, from soils after fertilizers are applied, and to supply the energy for fermenting and distilling corn into ethanol.

“Our work highlights the importance of looking at the full life cycle of energy production and use, not just at what comes out of tailpipes,” said Bioproducts and Biosystems Engineering Assistant Professor Jason Hill, co-author of the study. “We greatly underestimate transportation’s impacts on air quality if we ignore the upstream emissions from producing fuels or electricity.”

The researchers also point out that whereas recent studies on life cycle environmental impacts of transportation have focused mainly on greenhouse gas emissions, it is also important to consider air pollution and health. Their study provides a unique look at where life cycle emissions occur, how they move in the environment, and where people breathe that pollution. Their results provide unprecedented detail on the air quality-related health impacts of transportation fuel production and use.

“Air pollution has enormous health impacts, including increasing death rates across the U.S.,” said Civil, Environmental and Geo- Engineering Associate Professor Julian Marshall, co-author on this study. “This study provides valuable new information on how some transportation options would improve or worsen those health impacts.”

The study’s authors are Marshall and Tessum (College of Science and Engineering) and Hill (College of Food, Agricultural and Natural Resource Sciences), at the University of Minnesota. Marshall and Hill are also Resident Fellows of the University’s Institute on the Environment. This research was supported by the University of Minnesota’s Initiative for Renewable Energy and the Environment (IREE), the Office of Energy Efficiency & Renewable Energy of the U.S. Dept. of Energy (EERE/DOE), and the Agricultural and Food Research Initiative of the U.S. Dept. of Agriculture (USDA/AFRI).

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Source: University of Minnesota

Japan tests new satellite on robotic tractors in Riverina

PHOTO: A drone hovers over the Japanese robotic tractor trialled at Rice Research Australia in south-west NSW. (Laurissa Smith)

How would you feel about leaving a tractor to drive itself in one paddock, while you work in another ?

To the busy farmer, struggling to find local labour, it's an appealing concept.

Around the world, manufacturers, engineers and researchers are now trying to turn that into a reality.

In Japan, they've designed a self-steering robotic tractor which can sow, plough and spray crops.

An advanced positioning signal is transmitted from Japan's Quasi-Zenith Satellite System to control the tractor's movements.

The Japanese Government is funding trials to test the tractor on crops at Rice Research Australia near Jerilderie in south-west New South Wales.

Engineering firm Hitachi Zosen, machine manufacturer Yanmar, Hokkaido University and several other Australian universities are working together on the project.

Phil Collier, research director with Australia's Co-operative Research Centre for Spatial Information, hopes the technology can help farmers run their equipment with more accuracy.

"The satellites in the sky determine the position of the tractor in a global frame of reference," he said.

"The additional information that comes from the QZSS Satellites brings the precision down from several metres to two centimetres.

"The whole objective is to bring down the precision to a reliable level and a consistent level to allow that tractor to navigate its way down the rows of crops so things aren't getting run over."

If the trials prove successful, people in rural and remote Australia will have access to precise positioning, without having to rely on the mobile network.

At the moment, the robotic tractor is being tested on rice crops and paddocks late at night and into the early hours of the morning, when the satellite is passing over Australia.

The boundary of the field, the tractor's path and the start and end point of where it can turn are all programmed on a computer inside its cab.

This is to ensure the tractor doesn't veer off into a fence or an irrigation channel.

The CRC's Phil Collier says the technology's application won't be limited to precision farming.

"From mining to automated guidance of cars, anything where there's a level of machine automation required that's outside, then this technology has got that ability to solve that problem.

"My prediction, if I can be so bold, is that this sort of technology will move from sophisticated installations in machines like this to mobile phones in due course and people will have it in their back pocket."

The Japanese Government intends to deploy another three satellites in the near future, which will give Australia 24 hour coverage of the advanced positioning signals, once the technology is commercialised.

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Source: ABC

Switching to vehicles powered by electricity from renewables could save lives

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. Credit: © Dmitry Vereshchagin / Fotolia

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. This finding comes from a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts, published Monday, Dec. 15, 2014, in the Proceedings of the National Academy of Sciences.

The study also shows that switching to vehicles powered by electricity made using natural gas yields large health benefits. Conversely, vehicles running on corn ethanol or vehicles powered by coal-based or "grid average" electricity are worse for health; switching from gasoline to those fuels would increase the number of resulting deaths due to air pollution by 80 percent or more.

"These findings demonstrate the importance of clean electricity, such as from natural gas or renewables, in substantially reducing the negative health impacts of transportation," said Chris Tessum, co-author on the study and a researcher in the Department of Civil, Environmental, and Geo- Engineering in the University of Minnesota's College of Science and Engineering.

The University of Minnesota team estimated how concentrations of two important pollutants -- particulate matter and ground-level ozone -- change as a result of using various options for powering vehicles. Air pollution is the largest environmental health hazard in the U.S., in total killing more than 100,000 people per year. Air pollution increases rates of heart attack, stroke, and respiratory disease.

The authors looked at liquid biofuels, diesel, compressed natural gas, and electricity from a range of conventional and renewable sources. Their analysis included not only the pollution from vehicles, but also emissions generated during production of the fuels or electricity that power them. With ethanol, for example, air pollution is released from tractors on farms, from soils after fertilizers are applied, and to supply the energy for fermenting and distilling corn into ethanol.

"Our work highlights the importance of looking at the full life cycle of energy production and use, not just at what comes out of tailpipes," said Bioproducts and Biosystems Engineering Assistant Professor Jason Hill, co-author of the study. "We greatly underestimate transportation's impacts on air quality if we ignore the upstream emissions from producing fuels or electricity."

The researchers also point out that whereas recent studies on life cycle environmental impacts of transportation have focused mainly on greenhouse gas emissions, it is also important to consider air pollution and health. Their study provides a unique look at where life cycle emissions occur, how they move in the environment, and where people breathe that pollution. Their results provide unprecedented detail on the air quality-related health impacts of transportation fuel production and use.

"Air pollution has enormous health impacts, including increasing death rates across the U.S.," said Civil, Environmental and Geo- Engineering Associate Professor Julian Marshall, co-author on this study. "This study provides valuable new information on how some transportation options would improve or worsen those health impacts."

Source: University of Minnesota

Maintaining a reliable value of the cost of climate change

Car exhaust. Credit: © Wrangler / Fotolia

The term Social Cost of Carbon is a figure that puts a dollar value on the climate damages per ton of CO2 released, and is used by, among others, policymakers to help determine the costs and benefits of climate policies. In the latest issue of the journal Science, a group of economists and lawyers urge several improvements to the government's figure that would impose a regular, transparent and peer-reviewed process to ensure it is reliable and well-supported by the latest facts.

"By providing an estimate of the damages from an extra ton of CO2 emissions, the Social Cost of Carbon tells us how much money we should devote to mitigating emissions. It separates the efficient policies from the wasteful ones, and for this reason is an incredibly useful tool in devising climate policy," said Prof. Michael Greenstone, one of the authors of the analysis and the director of the Energy Policy Institute at the University of Chicago. "Having said that, every day we are learning more about the science behind climate change and the economic impacts it imposes. It's vital that policy keeps up as our knowledge evolves."

The researchers suggest that the value be updated routinely, specifically they recommend every five years to balance the need for incorporating the latest research with a thorough review process. Part of that process should entail a review by the National Academy of Science's National Research Council, they say, to allow outside experts to be part of the process and suggest changes. They also argue that a single Social Cost of Carbon estimate should be maintained and shared by all government agencies.

"Greenhouse gas emissions cause the same damage, regardless of whether they are emitted through car tailpipes or factory smokestacks, and no matter where in the world they come from," Greenstone said. "For this reason, one, consistently used and rigorously maintained estimate of climate damages is imperative to ensure our climate policies are providing the maximum benefits for the least costs."

William Pizer, the lead author of the study and a professor at Duke University, further emphasized this need.

"To ensure that value exists, it's important that we draw on the expertise of all government agencies, as well as independent experts in the field," Pizer said. "This level of high-quality collaboration and peer review would decrease the likelihood of political factors interfering with the process, and ensure we have the most robust Social Cost of Carbon."

The authors give an example of why such a consistent, collaborative and well-supported value is important. When the Social Cost of Carbon value used today, which was developed with a vigorous approach, is applied to the EPA's recent Clean Power Plan that limits emissions from existing power plants, the benefits of the rule vastly outweigh the damages. However, when applying a past value used by a single agency, the plan's benefits do not exceed the costs.

Additionally, Greenstone noted that the figure is not just a tool for policymakers. The courts, businesses and others use this figure to make important decisions on the impacts associated with climate change.

"The U.S. Social Cost of Carbon is becoming a focal estimate of the likely climate damages globally," Greenstone said. "It's critical that that we get this number right, because it will influence policy around the world."

Greenstone and some of his colleagues have initiated a larger project to determine an even more rigorously maintained cost of climate change at a global scale. "Our hope is that this ongoing research project will inform the periodic revisions of the Social Cost of Carbon that we advocate for in this Science article."

Source: University of Chicago

Switching to vehicles powered by electricity from renewables could save lives

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. Credit: © Dmitry Vereshchagin / Fotolia

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. This finding comes from a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts, published Monday, Dec. 15, 2014, in the Proceedings of the National Academy of Sciences.

The study also shows that switching to vehicles powered by electricity made using natural gas yields large health benefits. Conversely, vehicles running on corn ethanol or vehicles powered by coal-based or "grid average" electricity are worse for health; switching from gasoline to those fuels would increase the number of resulting deaths due to air pollution by 80 percent or more.

"These findings demonstrate the importance of clean electricity, such as from natural gas or renewables, in substantially reducing the negative health impacts of transportation," said Chris Tessum, co-author on the study and a researcher in the Department of Civil, Environmental, and Geo- Engineering in the University of Minnesota's College of Science and Engineering.

The University of Minnesota team estimated how concentrations of two important pollutants -- particulate matter and ground-level ozone -- change as a result of using various options for powering vehicles. Air pollution is the largest environmental health hazard in the U.S., in total killing more than 100,000 people per year. Air pollution increases rates of heart attack, stroke, and respiratory disease.

The authors looked at liquid biofuels, diesel, compressed natural gas, and electricity from a range of conventional and renewable sources. Their analysis included not only the pollution from vehicles, but also emissions generated during production of the fuels or electricity that power them. With ethanol, for example, air pollution is released from tractors on farms, from soils after fertilizers are applied, and to supply the energy for fermenting and distilling corn into ethanol.

"Our work highlights the importance of looking at the full life cycle of energy production and use, not just at what comes out of tailpipes," said Bioproducts and Biosystems Engineering Assistant Professor Jason Hill, co-author of the study. "We greatly underestimate transportation's impacts on air quality if we ignore the upstream emissions from producing fuels or electricity."

The researchers also point out that whereas recent studies on life cycle environmental impacts of transportation have focused mainly on greenhouse gas emissions, it is also important to consider air pollution and health. Their study provides a unique look at where life cycle emissions occur, how they move in the environment, and where people breathe that pollution. Their results provide unprecedented detail on the air quality-related health impacts of transportation fuel production and use.

"Air pollution has enormous health impacts, including increasing death rates across the U.S.," said Civil, Environmental and Geo- Engineering Associate Professor Julian Marshall, co-author on this study. "This study provides valuable new information on how some transportation options would improve or worsen those health impacts."

Source: University of Minnesota

Scientists get to the heart of fool's gold as a solar material

This crystal of iron pyrite shows the characteristic cubic crystals of 'fool's gold.' A new study led by Song Jin at the University of Wisconsin-Madison identifies defects in pyrite's crystal structure as a critical obstacle to building commercial solar cells from the cheap and abundant iron pyrite material. Credit: University of Wisconsin-Madison Geology Museum

As the installation of photovoltaic solar cells continues to accelerate, scientists are looking for inexpensive materials beyond the traditional silicon that can efficiently convert sunlight into electricity.

Theoretically, iron pyrite -- a cheap compound that makes a common mineral known as fool's gold -- could do the job, but when it works at all, the conversion efficiency remains frustratingly low. Now, a University of Wisconsin-Madison research team explains why that is, in a discovery that suggests how improvements in this promising material could lead to inexpensive yet efficient solar cells.

"We think we now understand why pyrite hasn't worked," says chemistry Professor Song Jin, "and that provides the hope, based on our understanding, for figuring out how to make it work. This could be even more difficult, but exciting and rewarding."

Although most commercial photovoltaic cells nowadays are based on silicon, the light-collecting film must be relatively thick and pure, which makes the production process costly and energy-intensive, says Jin.

A film of iron pyrite -- a compound built of iron and sulfur atoms -- could be 1,000 times thinner than silicon and still efficiently absorb sunlight.

Like silicon, iron and sulfur are common elements in Earth's crust, so solar cells made of iron pyrite could have a significant material cost advantage in large scale deployment. In fact, previous research that balanced factors like theoretical efficiency, materials availability, and extraction cost put iron pyrite at the top of the list of candidates for low-cost and large-scale photovoltaic materials.

In the current online edition of the Journal of the American Chemical Society, Jin and first author Miguel Cabán-Acevedo, a chemistry Ph.D. student, together with other scientists at UW-Madison, explain how they identified defects in the body of the iron pyrite material as the source of inefficiency. The research was supported by the U.S. Department of Energy.
In a photovoltaic material, absorption of sunlight creates oppositely charged carriers, called electrons and holes, that must be separated in order for sunlight to be converted to electricity. The efficiency of a photovoltaic solar cell can be judged by three parameters, Jin says, and the solar cells made of pyrite were almost totally deficient in one: voltage. Without a voltage, a cell cannot produce any power, he points out. Yet based on its essential parameters, iron pyrite should be a reasonably good solar material. "We wanted to know, why is the photovoltage so low," Jin says.

"We did a lot of different measurements and studies to look comprehensively at the problem," says Cabán-Acevedo, "and we think we have fully and definitively shown why pyrite, as a solar material, has not been efficient."

In exploring why pyrite was practically unable to make photovoltaic electricity, many researchers have looked at the surface of the crystals, but Cabán-Acevedo and Jin also looked inside. "If you think of this as a body, many have focused on the skin, but we also looked at the heart," says Cabán-Acevedo, "and we think the major problems lie inside, although there are also problems on the skin."

The internal problems, called "bulk defects," occur when a sulfur atom is missing from its expected place in the crystal structure. These defects are intrinsic to the material properties of iron pyrite and are present even in ultra-pure crystals. Their presence in large numbers eventually leads to the lack of photovoltage for solar cells based on iron pyrite crystals.
Science advances by comprehending causes, Jin says. "Our message is that now we understand why pyrite does not work. If you don't understand something, you must try to solve it by trial and error. Once you understand it, you can use rational design to overcome the obstacle. You don't have to stumble around in the dark."

Source: University of Wisconsin-Madison

A New technique could harvest more of the sun's energy

An ultra-sensitive needle measures the voltage that is generated while the nanospheres are illuminated.
Credit: AMOLF/Tremani - Figure: Artist impression of the plasmo-electric effect.

As solar panels become less expensive and capable of generating more power, solar energy is becoming a more commercially viable alternative source of electricity. However, the photovoltaic cells now used to turn sunlight into electricity can only absorb and use a small fraction of that light, and that means a significant amount of solar energy goes untapped.

A new technology created by researchers from Caltech, and described in a paper published online in the October 30 issue of Science Express, represents a first step toward harnessing that lost energy.

Sunlight is composed of many wavelengths of light. In a traditional solar panel, silicon atoms are struck by sunlight and the atoms' outermost electrons absorb energy from some of these wavelengths of sunlight, causing the electrons to get excited. Once the excited electrons absorb enough energy to jump free from the silicon atoms, they can flow independently through the material to produce electricity. This is called the photovoltaic effect -- a phenomenon that takes place in a solar panel's photovoltaic cells.

Although silicon-based photovoltaic cells can absorb light wavelengths that fall in the visible spectrum -- light that is visible to the human eye -- longer wavelengths such as infrared light pass through the silicon. These wavelengths of light pass right through the silicon and never get converted to electricity -- and in the case of infrared, they are normally lost as unwanted heat.

"The silicon absorbs only a certain fraction of the spectrum, and it's transparent to the rest. If I put a photovoltaic module on my roof, the silicon absorbs that portion of the spectrum, and some of that light gets converted into power. But the rest of it ends up just heating up my roof," says Harry A. Atwater, the Howard Hughes Professor of Applied Physics and Materials Science; director, Resnick Sustainability Institute, who led the study.
Now, Atwater and his colleagues have found a way to absorb and make use of these infrared waves with a structure composed not of silicon, but entirely of metal.

The new technique they've developed is based on a phenomenon observed in metallic structures known as plasmon resonance. Plasmons are coordinated waves, or ripples, of electrons that exist on the surfaces of metals at the point where the metal meets the air.
While the plasmon resonances of metals are predetermined in nature, Atwater and his colleagues found that those resonances are capable of being tuned to other wavelengths when the metals are made into tiny nanostructures in the lab.

"Normally in a metal like silver or copper or gold, the density of electrons in that metal is fixed; it's just a property of the material," Atwater says. "But in the lab, I can add electrons to the atoms of metal nanostructures and charge them up. And when I do that, the resonance frequency will change."

"We've demonstrated that these resonantly excited metal surfaces can produce a potential" -- an effect very similar to rubbing a glass rod with a piece of fur: you deposit electrons on the glass rod. "You charge it up, or build up an electrostatic charge that can be discharged as a mild shock," he says. "So similarly, exciting these metal nanostructures near their resonance charges up those metal structures, producing an electrostatic potential that you can measure."

This electrostatic potential is a first step in the creation of electricity, Atwater says. "If we can develop a way to produce a steady-state current, this could potentially be a power source. He envisions a solar cell using the plasmoelectric effect someday being used in tandem with photovoltaic cells to harness both visible and infrared light for the creation of electricity.

Although such solar cells are still on the horizon, the new technique could even now be incorporated into new types of sensors that detect light based on the electrostatic potential.
"Like all such inventions or discoveries, the path of this technology is unpredictable," Atwater says. "But any time you can demonstrate a new effect to create a sensor for light, that finding has almost always yielded some kind of new product."


This work was published in a paper titled, "Plasmoelectric Potentials in Metal Nanostructures." Other coauthors include first author Matthew T. Sheldon, a former postdoctoral scholar at Caltech; Ana M. Brown, an applied physics graduate student at Caltech; and Jorik van de Groep and Albert Polman from the FOM Institute AMOLF in Amsterdam. The study was funded by the Department of Energy, the Netherlands Organization for Scientific Research, and an NSF Graduate Research Fellowship.

Source: California Institute of Technology