RV: Discovery of Historical Photos Sheds Light on Greenland Ice Loss

Fuente: Research News from The Ohio State University
Expuesto el: martes, 29 de mayo de 2012 20:47
Autor: Research News from The Ohio State University
Asunto: Discovery of Historical Photos Sheds Light on Greenland Ice Loss

 

DISCOVERY OF HISTORICAL PHOTOS SHEDS LIGHT ON GREENLAND ICE LOSS COLUMBUS, Ohio - A chance discovery of 80-year-old photo plates in a Danish basement is providing new insight into how Greenland glaciers are melting today. Researchers at the National Survey and Cadastre of Denmark - that country's federal agency responsible for surveys and mapping - had been storing the glass plates since explorer Knud Rasmussen's expedition to the southeast coast of Greenland in the early 1930s. In this week's online edition of Nature Geoscience, Ohio State University researchers and colleagues in Denmark describe how they analyzed ice loss in the region by comparing the images on the plates to aerial photographs and satellite images taken from World War II to today. Taken together, the imagery shows that glaciers in the region were melting even faster in the 1930s than they are today, said Jason Box, associate professor of geography and researcher at the Byrd Polar Research Center at Ohio State. A brief cooling period starting in the mid-20th century allowed new ice to form, and then the melting began to accelerate again in the 2000s. Jason Box "Because of this study, we now have a detailed historical analogue for more recent glacier loss," Box said. "And we've confirmed that glaciers are very sensitive indicators of climate." Pre-satellite observations of Greenland glaciers are rare. Anders Anker Bjork, doctoral fellow at the Natural History Museum of Denmark and lead author of the study, is trying to compile all such imagery. He found a clue in the archives of The Arctic Institute in Copenhagen in 2011. "We found flight journals for some old planes, and in them was a reference to National Survey and Cadastre of Denmark," Bjork said. As it happens, researchers at the National Survey had already contacted Bjork about a find of their own. "They were cleaning up in the basement and had found some old glass plates with glaciers on them. The reason the plates were forgotten was that they were recorded for mapping, and once the map was produced they didn't have much value." Those plates turned out to be documentation of Rasmussen's 7th Thule Expedition to Greenland. They contained aerial photographs of land, sea and glaciers in the southeast region of the country, along with travel photos of Rasmussen's team. The researchers digitized all the old images and used software to look for differences in the shape of the southeast Greenland coastline where the ice meets the Atlantic Ocean. Then they calculated the distance the ice front moved in each time period. Over the 80 years, two events stand out: glacial retreats from 1933-1934 and 2000-2010. In the 1930s, fewer glaciers were melting than are today, and most of those that were melting were land-terminating glaciers, meaning that they did not contact the sea. Those that were melting retreated an average of 20 meters per year - the fastest retreating at 374 meters per year. Fifty-five percent of the glaciers in the study had similar or higher retreat rates during the 1930s than they do today. Still, more glaciers in southeast Greenland are retreating today, and the average ice loss is 50 meters per year. That's because a few glaciers with very fast melting rates - including one retreating at 887 meters per year - boost the overall average. But to Box, the most interesting part of the study is what happened between the two melting events. From 1943-1972, southeast Greenland cooled - probably due to sulfur pollution, which reflects sunlight away from the earth. Sulfur dioxide is a poisonous gas produced by volcanoes and industrial processes. It has been tied to serious health problems and death, and is also the main ingredient in acid rain. Its presence in the atmosphere peaked just after the Clean Air Act was established in 1963. As it was removed from the atmosphere, the earlier warming resumed. The important point is not that deadly pollution caused the climate to cool, but rather that the brief cooling allowed researchers to see how Greenland ice responded to the changing climate. Email this to a friend "Because of this study, we now have a detailed historical analogue for more recent glacier loss," Box said. "And we've confirmed that glaciers are very sensitive indicators of climate." The glaciers responded to the cooling more rapidly than researchers had seen in earlier studies. Sixty percent of the glaciers advanced during that time, while 12 percent were stationary. And now that the warming has resumed, the glacial retreat is dominated by marine-terminating outlet glaciers, the melting of which contributes to sea level rise. "From these images, we see that the mid-century cooling stabilized the glaciers," Box said. "That suggests that if we want to stabilize today's accelerating ice loss, we need to see a little cooling of our own." Southeast Greenland is a good place to study the effects of climate change, he explained, because the region is closely tied to air and water circulation patterns in the North Atlantic. "By far, more storms pass through this region - transporting heat into the Arctic - than anywhere else in the Northern Hemisphere. Climate change brings changes in snowfall and air temperature that compete for influence on a glacier’s net behavior," he said. Co-authors on the study include Kurt H. Kjaer, Niels J. Korsgaard, Kristian K. Kjeldsen, and Svend Funder at the Natural History Museum of Denmark, University of Copenhagen; Shfaqat A. Khan of the National Space Institute, Technical University of Denmark; Camilla S. Andresen of the Department of Marine Geology and Glaciology at the Geological Survey of Denmark and Greenland; and Nicolaj K. Larsen of the Department of Geoscience at Aarhus University. Photos, satellite images and other data for the study were provided by the National Survey and Cadastre; The Scott Polar Research Institute in the United Kingdom; the Arctic Institute in Denmark; researchers Bea Csatho and Sudhagar Nagarajan of the Geology Department at the University at Buffalo; and the NASA Land Processes Distributed Active Archive Center at the USGS/Earth Resources Observation and Science Center of Sioux Falls, S.D. Andreas Pedersen of the Danish company MapWork wrote the script for the software used in the study. This work is a part of the RinkProject funded by the Danish Research Council and the Commission for Scientific Research in Greenland. # Contact: Jason Box, (614) 247- 6899; Box.11@osu.edu Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu Editor's note: Images from the 7th Thule Expedition are available from Pam Frost Gorder.

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RV: Mailman School Study Links Mothball Ingredient to Damage in Children's Chromosomes

Fuente: Columbia University News
Expuesto el: miércoles, 30 de mayo de 2012 17:19
Autor: maf2182@columbia.edu
Asunto: Mailman School Study Links Mothball Ingredient to Damage in Children’s Chromosomes

 

According to a new study, children exposed to high levels of the common air pollutant naphthalene are at increased risk for chromosomal aberrations (CAs), which have been previously associated with cancer. These include chromosomal translocations, a potentially more harmful and long-lasting subtype of CAs. Researchers from the Columbia Center for Children’s Environmental Health (CCCEH) at the Mailman School of Public Health, Columbia University Medical Center, and the Centers for Disease Control and Prevention (CDC) report the new findings in Cancer, Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research. Naphthalene is found in both outdoor and indoor urban air. It is present in automotive exhaust, tobacco smoke, and is the primary component of household mothball fumes. Classified as a possible carcinogen by the International Agency for Cancer Research, naphthalene belongs to a class of air pollutants called polycyclic aromatic hydrocarbons (PAH). Prior research at the CCCEH has established a link between prenatal exposure to PAH and increased risk for childhood obesity, IQ deficits, and CAs. The new study is the first to present evidence in humans of CAs, including translocations, associated with exposure to one specific PAH—naphthalene—during childhood. The researchers followed 113 children, age 5, who are part of a larger cohort study in New York City. They assessed the children’s exposure to naphthalene; a CDC laboratory measured levels of its metabolites—1- and 2-naphthol—in urine samples. (Metabolites are products of the body’s metabolism, and can serve as marker for the presence of a chemical.) Researchers also measured CAs in the children’s white blood cells using a technique called fluorescent in situ hybridization. Chromosomal aberrations were present in 30 children; of these, 11 had translocations. With every doubling of levels of 1- and 2-naphthol, translocations were 1.55 and 1.92 times more likely, respectively, to occur. CAs have been associated with increased cancer risk in adults. Translocations are of special concern as they result in a portion of one chromosome being juxtaposed to a portion of another chromosome, potentially scrambling the genetic script. “Translocations can persist for years after exposure. Some accumulated damage will be repaired, but not everyone’s repair capacity is the same. Previous studies have suggested that chromosomal breaks can double an adult’s lifetime risk for cancer, though implications for children are unknown,” says first author Manuela A. Orjuela, MD, ScM, assistant professor of clinical environmental health sciences and pediatrics (oncology) at Columbia University Medical Center and a pediatric oncologist at NewYork-Presbyterian Morgan Stanley Children’s Hospital. To obtain a better sense of the long-term consequences of naphthalene exposure, Dr. Orjuela and other CCCEH investigators are following some of the children in the study as they reach fourth grade. While they expect to see further translocations, they do not expect to see any signs of cancer in the white blood cells. “So far, the translocations seem to be random, and there has been no evidence of the specific translocations that are known to be associated with leukemia. This is entirely expected; leukemia is very rare.” Frederica Perera, DrPH, senior author on the paper, adds that “the findings provide yet more evidence of the vulnerability of the young child to carcinogenic air pollutants.” The researchers hypothesized that naphthalene exposure was primarily from mothballs, which can release high levels of the chemical. Furthermore, according to previous research, some Caribbean immigrant families use mothballs as an air freshener. Other important sources of naphthalene in indoor air are tobacco smoke, paint fumes, cooking, and heating. The new findings have implications beyond the urban environment as elevated levels of naphthalene metabolites have been documented in rural communities using biomass-burning stoves (coal, wood)—another source of PAH exposure. The research was supported by the National Institutes of Health (grants R01ES12732, U01CA159157, 5P01ES09600, R01 ES013163, P50 ES015905, 5RO1ES08977, RO1ES111158, RO1ES012468, an   d P30 ES09089), the U.S. Environmental Protection Agency (STAR grants RD832096, R827027, 8260901, and RR00645), and the New York Community Trust. The authors declare no conflicts of interest. May 29, 2012

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RV: Berkeley Lab study assesses residential cooking exhaust hoods' ability to vent pollutants

Fuente: Berkeley Lab News Center
Expuesto el: miércoles, 30 de mayo de 2012 18:36
Autor: jonweiner
Asunto: Berkeley Lab study assesses residential cooking exhaust hoods’ ability to vent pollutants

 

News Release Cooking exhaust hoods designed for home kitchens vary widely in their ability to capture and vent away the air pollutants generated by the gas burners on cook stoves, according to a study by two Lawrence Berkeley National Laboratory (Berkeley Lab) scientists. Of seven representative devices they tested, the capture efficiency varied from less than 15 percent to more than 98 percent. The study, by Woody Delp and Brett Singer of Berkeley Lab’s Environmental Energy Technologies Division, measured their pollutant capture efficiency, sound level generated by their fans, and airflow. Cooking exhaust hoods vent such pollutants as carbon monoxide, nitrogen oxides, formaldehyde, and fine particulates such as soot generated during cooking. Berkeley Lab's Brett Singer (Photo: Roy Kaltschmidt) While the exhaust hoods they tested varied widely in performance, they found that all exhaust hoods do a better job of capturing pollutants generated by the two back burners of a four-burner stove than its front burners. “Even a moderately effective exhaust hood can reduce a stove user’s exposure to pollutants,” says Delp, “and using the back burners preferentially over the front burners helps reduce exposure even more.” However, their research suggests that design improvements can increase the ability of hoods to capture pollutants and reduce their noisiness without increasing their energy use. The study addresses the pollutants emitted by burners on the stove, but the process of cooking foods, for example by frying or stir frying, also generates pollutants. The research team has not confirmed that their results are applicable to cooking foods, but they believe their results are applicable to cooking, and they have funding for a follow-up study to confirm that the test method is applicable to assessing the capture of pollutants from the cooking process. They are also working on developing test standards that would allow for products to be rated for their performance in capturing pollutants. Seven representative models tested Pollutant capture efficiency is the percentage of pollutants at the cooking surface captured by the exhaust hood. Delp and Singer selected models that are representative of the different types of undercabinet exhaust hoods available in the retail marketplace in the U.S. Several hoods covered only part of the two-front burners of the gas stove. The coverage of one hood, a premium model, extended out beyond the front burners. Some of the models had grease screens, or metal covering their bottoms, and some were open underneath. Two were ENERGY STAR-rated. The seven ranged in price from $40 for an economy model to $650, with most falling in the $250 to $350 range. ENERGY STAR ratings for exhaust hoods only consider a hood’s energy use and noise level, not its efficiency at capturing exhaust. Their results showed that exhaust hoods varied widely in their performance, and while most of the hoods performed relatively well at venting exhaust gases, most do not do everything well—some hoods had high capture efficiencies, some were very quiet, and some were energy-efficient, but rarely were all three qualities captured in a single exhaust hood. The hoods did better at capturing pollutants from the two back burners of the stove than from its front burners. Hoods that achieved airflows recommended by the Home Ventilating Institute’s HV1 standard showed capture efficiencies of about 80 percent or greater for back burners but only 60 percent or greater for the oven and 50 percent or greater for front burners. Open hoods had higher capture efficiency than those with grease screen- and metal-covered bottoms. The hood with the highest capture efficiency, exceeding 80 percent for front burners, was a model with a large, open hood that covered most of the front burners, but it generated sound levels too high for normal conversation. The capture efficiency of hoods meeting ENERGY STAR criteria was less than 30 percent for front and oven burners. “These results suggest ways that manufacturers can improve the performance of their products,” says Singer. “Improving the geometry of the hoods—by making them deeper front to back and using methods such as recessed grease traps, blower entries up inside the hood, and better fans and motors will improve their capture efficiency.” This research was funded by the California Energy Commission, the U.S. Department of Energy, the U.S. Department of Housing and Urban Development, and the U.S. Environmental Protection Agency. # # # “Performance Assessment of U.S. Residential Cooking Exhaust Hoods,“ by Woody Delp and Brett Singer, is published in Environmental Science & Technology. Links American Chemical Society press release Performance Assessment of U.S. Residential Cooking Exhaust Hoods TAGS: EETD, energy, energy efficiency, exhaust, pollutants VIEWS: 20 Print

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RV: Tuna caught off California carry radiation from the Japanese disaster, Stanford scientist finds

Fuente: Stanford News Headlines
Expuesto el: miércoles, 30 de mayo de 2012 8:00
Autor: Stanford News Headlines
Asunto: Tuna caught off California carry radiation from the Japanese disaster, Stanford scientist finds

 

By Katy Ashe Tom Puchner/Creative Commons The radiation provides 'unequivocal evidence' that these fish transported radioactivity across the Pacific Ocean, the researchers said. Radiation from the nuclear reactor disaster in Japan has been found in bluefin tuna in waters off San Diego by researchers from Stanford and Stony Brook University. It marks the first instance of radioactive materials being transported through the sea by migrating animals. The radiation levels in the fish, caught by recreational anglers, are not considered to be a threat to human health. The researchers reported in the Proceedings of the National Academy of Sciences how they used the radioactive cesium in the tuna to understand the origin and timing of their migration across the Pacific, showing that the radioactivity emitted by the disaster can be used as a new tool for tracking migration patterns. On March 11, 2011, a tsunami flooded the Fukushima Dai-ichi nuclear power plants in Japan, leading to the failure of cooling equipment inside. The plants overheated, spilling their radioactive cooling water into the sea. It was the largest radioactive release into the ocean in the history of nuclear accidents. The spill left behind two radioactive isotopes of cesium. One was previously undetectable in the ocean off the California coast, and the other had previously existed only in very low levels in radiation left behind from the fallout of atmospheric tests of nuclear weapons. Using radioactivity to retrace tuna route After the Fukushima spill, the Japanese government monitored the levels of radioactivity in seafood caught near shore, and standards were set for contamination. But radioactivity was not being tracked in the migratory species that pass through Japanese waters.  Discovering radioactive cesium isotopes in Pacific bluefin was an unexpected discovery for the scientists involved in the study. "We never thought to study radioactivity in migratory species," said Zofia Baumann, a postdoctoral investigator at Stony Brook and coauthor of the study. In June of last year, Baumann was measuring the levels of cesium in the zooplankton and small fish that live near the spill site. The researchers began to wonder if they would see the same radioactive cesium isotopes show up in Pacific bluefin tuna that had traveled from Japan. It is believed that all Pacific bluefin tuna are reared in the coastal waters of Japan and the Philippines. When they are full size, tuna can weigh more than 1,000 pounds, measure 10 feet in length and live up to 26 years; as 1-year-olds, they are strong enough to swim across the Pacific Ocean. Some unknown fraction of the population embarks on this transoceanic journey from Japan to the California Current. "The area of the Fukushima spill is an area of high use for juveniles," said Daniel Madigan, a Stanford doctoral student in marine biology and the lead author of the study.  Many tuna spend their first year in the coastal waters off Japan feeding and gathering strength for the long migration ahead of them.  So, he thought, there was a possibility that some of the tuna feeding in the coastal areas around Japan had accumulated radioactive cesium. In order to test this hypothesis Madigan collected tissue samples from young bluefin tuna that were caught off the coast of San Diego in August 2011.  He sent them to the laboratory at Stony Brook to be tested by Baumann for radioactive cesium. "We thought that it was unlikely that we would find anything," said Professor Nicholas Fisher of Stony Brook, a coauthor of the study, "We were very surprised at the results – all of them had clearly detectable levels." The radiation provides "unequivocal evidence" that these fish transported radioactivity across the Pacific Ocean, the researchers said.  Furthermore, the ratio between the two isotopes of cesium allowed the scientists to determine that this particular group of Pacific bluefin tuna had left Japan approximately four months earlier, after spending less than a month in the contaminated waters near Japan. Not a public health concern "All living things are radioactive," said Fisher, "primarily attributable to the naturally occurring potassium-40.  The potassium-40 radioactivity in the bluefin tuna was over 30 times higher than that from the radioactive cesium.  So, the radioactivity from the spill really only adds 3 percent more radioactivity than the background level."  This study opens up the door for radioactivity from the Fukushima disaster to serve as a valuable tool in mapping the paths of little-understood migratory species.  "We now know that we can use these isotopes to trace biological movements from Japan across long distances," said Fisher, "just like scientists have used isotopes in the past to track ocean currents."  This new tool can be used alongside other tools like incidental catch reports and electronic tagging to piece together the journeys of the creatures that travel the oceans. "This is an example of how events don't happen in a vacuum," said Madigan, "These tuna carried this radiation across the entire Pacific, the largest ocean on the planet." Katy Ashe is an intern at Stanford News Service.

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RV: New materials could slash energy costs for CO2 capture

Fuente: Rice University News & Media » Current News
Expuesto el: miércoles, 30 de mayo de 2012 16:38
Autor: Jade Boyd
Asunto: New materials could slash energy costs for CO2 capture

 

Study IDs ‘zeolite’ minerals that are one-third more efficient for carbon capture A detailed analysis of more than 4 million absorbent minerals has determined that new materials could help electricity producers slash as much as 30 percent of the “parasitic energy” costs associated with removing carbon dioxide from power plant emissions. The research by scientists at Rice University, the University of California, Berkeley, Lawrence Berkeley National Laboratory (LBNL) and the Electric Power Research Institute (EPRI) was published online this week in the journal Nature Materials. New materials could reduce the energy required to remove CO2 from power plant emissions. Coal- and natural-gas-fired power plants account for about half of the carbon dioxide (CO2) that humans add to the atmosphere each year, but current technology for capturing that CO2 and storing it underground can gobble up as much as one-third of the steam the plant could otherwise use to make electricity. In the new study, researchers found that commonly used industrial minerals called zeolites could significantly improve the energy efficiency of “carbon capture” technology. “It looks like we can beat the current state-of-the-art technology by about 30 percent, and not just with one or two zeolites,” said study co-author Michael Deem, Rice’s John W. Cox Professor of Bioengineering and professor of physics and astronomy. “Our analysis showed that dozens of zeolites are more efficient than the amine absorbents currently used for CO2 capture.” Commercial power plants do not capture CO2 on a large scale, but the technology has been tested at pilot plants. At test plants, flue gases are funneled through a bath of ammonia-like chemicals called amines. The amines are then boiled to release the captured CO2, and additional energy is required to compress the CO2 so it can be pumped underground. The “parasitic energy” costs associated with current technology is high; up to one-third of the steam that could be used to generate electricity is siphoned off to boil the amines and liquefy the CO2. Artist Kelly Harvey evoked images of the sea and a coral reef to hint at the diversity of structures in Rice's zeolite database. Deem said the new study is the first to compare the “parasitic energy” costs for a whole class of carbon-capture materials. The study found dozens of zeolites that could remove CO2 from flue gas for a lower energy cost than amines could. Zeolites are common minerals made mostly of silicon and oxygen. About 40 exist in nature, and there are about 160 man-made types. All zeolites are highly porous — like microscopic Swiss cheese — and the pore sizes and shapes vary depending upon how the silicon and oxygen atoms are arranged. The pores act like tiny reaction vessels that capture, sort and spur chemical reactions of various kinds, depending upon the size and shape of the pores. The chemical industry uses zeolites to refine gasoline and to make laundry detergent and many other products. In 2007, Deem and colleagues used computers to calculate millions of atomic formulations for zeolites, and they have continued to add information to the resulting catalog, which contains about 4 million zeolite structures. In the new study, the zeolite database was examined with a new computer model designed to identify candidates for CO2 capture. The new model was created by a team led by co-author Berend Smit, UC Berkeley’s Chancellor’s Professor in the departments of chemical and biomolecular engineering and of chemistry and a faculty senior scientist at LBNL. Smit and his UC Berkeley group worked with study co-author Abhoyjit Bhown, a technical executive at EPRI, to establish the best criteria for a good carbon capture material. Focusing on the energy costs of capture, release and compression, they created a formula to calculate the energy consumption for any materials in the zeolite database. In this zeolite structure, the arrangement of oxygen atoms (red) and silicon atoms (tan) influences the regions in the pores (colored surface) where CO2 can be captured. Running the painstaking calculations to compare the CO2-capture abilities of each zeolite would have taken approximately five years with standard central processing units (CPUs), so Smit and his colleagues at UC-Berkeley and LBNL created a new way to run the calculations on graphics processing units, or GPUs — the processors used in PC graphics cards. Deem said the GPU technique cut the compute time to about one month, which made the project feasible. Smit said, “Our database of carbon capture materials is going to be coupled to a model of a full plant design, so if we have a new material, we can immediately see whether this material makes sense for an actual design.” Study co-authors include graduate students Li-Chiang Lin and Joseph Swisher, both of UC Berkeley; Adam Berger of the EPRI; Richard Martin, Chris Rycroft and Maciej Haranczyk, all of LBNL’s Computational Research Division; and postdoctoral fellows Jihan Kim and Kuldeep Jariwala of LBNL’s Materials Science Division. This research was supported by the Department of Energy, the Advanced Research Projects Agency–Energy and EPRI’s Office of Technology Innovation.

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RV: Groundwater Depletion in Semiarid Regions of Texas and California Threatens U.S. Food Security

Fuente: University of Texas at Austin
Expuesto el: martes, 29 de mayo de 2012 17:04
Autor: Marc Airhart
Asunto: Groundwater Depletion in Semiarid Regions of Texas and California Threatens U.S. Food Security

 

May 29, 2012 AUSTIN, Texas — The nation's food supply may be vulnerable to rapid groundwater depletion from irrigated agriculture, according to a new study by researchers at The University of Texas at Austin and elsewhere. Groundwater depletion has been most severe in the purple areas indicated on these maps of (A) the High Plains and (B) California's Central Valley. These heavily affected areas are concentrated in parts of the Texas Panhandle, western Kansas, and the Tulare Basin in California's Central Valley. Changes in groundwater levels in (A) are adapted from a 2009 report by the U.S. Geological Survey and in (B) from a 1989 report by the USGS. The study, which appears in the journal Proceedings of the National Academy of Sciences, paints the highest resolution picture yet of how groundwater depletion varies across space and time in California's Central Valley and the High Plains of the central U.S. Researchers hope this information will enable more sustainable use of water in these areas, although they think irrigated agriculture may be unsustainable in some parts. "We're already seeing changes in both areas," said Bridget Scanlon, senior research scientist at The University of Texas at Austin's Bureau of Economic Geology and lead author of the study. "We're seeing decreases in rural populations in the High Plains. Increasing urbanization is replacing farms in the Central Valley. And during droughts some farmers are forced to fallow their land. These trends will only accelerate as water scarcity issues become more severe." Three results of the new study are particularly striking: First, during the most recent drought in California's Central Valley, from 2006 to 2009, farmers in the south depleted enough groundwater to fill the nation's largest man-made reservoir, Lake Mead near Las Vegas—a level of groundwater depletion that is unsustainable at current recharge rates. Second, a third of the groundwater depletion in the High Plains occurs in just 4% of the land area. And third, the researchers project that if current trends continue some parts of the southern High Plains that currently support irrigated agriculture, mostly in the Texas Panhandle and western Kansas, will be unable to do so within a few decades. California's Central Valley is sometimes called the nation's "fruit and vegetable basket." The High Plains, which run from northwest Texas to southern Wyoming and South Dakota, are sometimes called the country's "grain basket." Combined, these two regions produced agricultural products worth $56 billion in 2007, accounting for much of the nation's food production. They also account for half of all groundwater depletion in the U.S., mainly as a result of irrigating crops. In the early 20th century, farmers in California's Central Valley began pumping groundwater to irrigate their crops. Over time, groundwater levels dropped as much as 400 feet in some places. From the 1930s to ’70s, state and federal agencies built a system of dams, reservoirs and canals to transfer water from the relatively water-rich north to the very dry south. Since then, groundwater levels in some areas have risen as much as 300 feet. In the High Plains, farmers first began large-scale pumping of groundwater for crop irrigation in the 1930s and ’40s; but irrigation greatly expanded in response to the 1950s drought. Since then, groundwater levels there have steadily declined, in some places more than 150 feet. Scanlon and her colleagues at the U.S. Geological Survey and the Université de Rennes in France used water level records from thousands of wells, data from NASA's GRACE satellites, and computer models to study groundwater depletion in the two regions. GRACE satellites monitor changes in Earth’s gravity field which are controlled primarily by variations in water storage. Byron Tapley, director of the university's Center for Space Research, led the development of the GRACE satellites, which recently celebrated their 10th anniversary. Scanlon and her colleagues suggested several ways to make irrigated agriculture in the Central Valley more sustainable: Replace flood irrigation systems (used on about half of crops) with more efficient sprinkle and drip systems and expand the practice of groundwater banking—storing excess surface water in times of plenty in the same natural aquifers that supply groundwater for irrigation. Groundwater banks currently store 2 to 3 cubic kilometers of water in California, similar to or greater than storage capacities of many of the large surface water reservoirs in the state. Groundwater banks provide a valuable approach for evening out water supplies during climate extremes ranging from droughts to floods. For various reasons, Scanlon and other experts don't think these or other engineering approaches will solve the problem in the High Plains. When groundwater levels drop too low to support irrigated farming in some areas, farmers there will be forced to switch from irrigated crops such as corn to non-irrigated crops such as sorghum, or to rangeland. The transition could be economically challenging because non-irrigated crops generate about half the yield of irrigated crops and are far more vulnerable to droughts. "Basically irrigated agriculture in much of the southern High Plains is unsustainable," said Scanlon. For more information, contact: Marc Airhart, Geology Foundation, Jackson School of Geosciences, 512 471 2241.

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RV: Study finds emissions from widely used cookstoves vary with use

Fuente: Illinois News Bureau: Research
Expuesto el: martes, 29 de mayo de 2012 21:00
Autor: Illinois News Bureau: Research
Asunto: Study finds emissions from widely used cookstoves vary with use

 

5/29/2012 | Liz Ahlberg, Physical Sciences Editor | 217-244-1073; eahlberg@illinois.edu CHAMPAIGN, Ill. — The smoke rising from a cookstove fills the air with the tantalizing aroma of dinner – and a cloud of pollutants and particles that threaten both health and the environment. How families in developing countries use their cookstoves has a big effect on emissions from those stoves, and laboratory emission tests don’t accurately reflect real-world operations, according to a study by University of Illinois researchers. “The understanding of how people really use combustion devices is important if we’re going to optimize that device,” said study leader Tami Bond, a professor of civil and environmental engineering at the U. of I. | UI Photo Biomass-burning cookstoves are used throughout the developing world, using wood, agricultural waste and other organic matter as fuel. They are also a major cause of poor air quality in the regions where use is prevalent. Policymakers and nonprofit organizations are working to develop and distribute “improved” cookstoves, for example, adding insulation or chimneys to reduce emissions. They are especially concerned with fine particles that are emitted, which cause health problems and also affect climate. Much like automobiles undergo emission testing before hitting the market, cookstoves are tested in the lab before distribution to gauge how effective improvements are at reducing emissions. But if the conditions aren’t the same as how people use them at home, then the changes that designers make to the stove may not actually reduce emissions in the field. “The understanding of how people really use combustion devices is important if we’re going to optimize that device,” said study leader Tami Bond, a professor of civil and environmental engineering at U. of I. “In the laboratory, where tests are conducted by trained people, there’s a lot more attention to operating the stove carefully. At home, people are not as concerned with its operation; they’re more concerned with making a meal. So they operate in ways that are non-optimal.” However, these variations in use are masked by the current methods of testing, which use only average values to determine emissions – sort of like a snapshot of the stove in operation, not accounting for variation in use. Bond’s team developed a real-time analysis technique called Patterns of Real-Time Emissions Data (PaRTED) that allows researchers to compare emissions under different operating conditions and to measure how often a stove operates under certain conditions in the field. “Wood burning is like a dance,” Bond said. “A movie gives you a better understanding than a photograph. This is a way to make movies of how users change as they make fires, and that can help people understand emission rates and make better stoves.” Using PaRTED, Bond’s team tested cookstoves in use in a village in Honduras and compared the field results to lab results. The researchers found that operation under less-than-ideal conditions produces the highest emissions. They also found that in the field, stoves are rarely used under optimal conditions, a scenario not reproduced in laboratory tests. The team compared emission profiles, or the chemical makeup of the smoke, from traditional cookstoves and two types of improved stoves: insulated stoves and stoves with chimneys. They found that although stoves with an insulated combustion chamber could increase overall efficiency, they did not significantly reduce emissions per mass of fuel burned. Chimneys did reduce certain types of particle emissions – but chimneys did not cut down on black particles, the type most harmful to climate. “Our measurements confirm that changes in stove design cause a change in the way they operate,” Bond said. “I think people weren’t aware that changes in design actually change the profile of the emissions rather than just reducing emissions.” Next, the researchers will use PaRTED analysis to study variations in cookstove use in different regions of the world. Bond hopes that PaRTED and this study will inform future testing protocols for cookstoves in the lab, enabling researchers to more accurately test under realistic conditions and providing insight into a whole range of possible use scenarios. “Insulated and chimneyed stoves are a step in the right direction, but not as far as we need to go to get really clean stoves,” Bond said. “The next step is to identify both the patterns of stove operation and the factors that lead to the characteristic profile of operation so that those can be brought into the lab and optimized. The cookstove world is moving toward having emission standards. It would be best if those standards were relevant to real operations.” The researchers published their study in the journal Environmental Science and Technology. The National Science Foundation and the Environmental Protection Agency supported this work. Postdoctoral research associate Yanju Chen and Bond group alumnus Christoph Roden were co-authors of the paper. Editor's note: To reach Tami Bond, email yark@illinois.edu. The paper, “Characterizing Biofuel Combustion With Patterns of Real-Time Emission Data (PaRTED),” is available online.

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RV: Computer model fuels efficient carbon capture

Fuente: UC Newsroom RSS Feed
Expuesto el: martes, 29 de mayo de 2012 17:00
Autor: help@ucop.edu
Asunto: Computer model fuels efficient carbon capture

 

BERKELEY — When power plants begin capturing their carbon emissions to reduce greenhouse gases — and to most in the electric power industry, it's a question of when, not if — it will be an expensive undertaking. Current technologies would use about one-third of the energy generated by the plants — what's called "parasitic energy" — and, as a result, substantially drive up the price of electricity. But a new computer model developed by University of California, Berkeley, chemists shows that less expensive technologies are on the horizon. They will use new solid materials like zeolites and metal oxide frameworks (MOFs) that more efficiently capture carbon dioxide so that it can be sequestered underground. "The current on-the-shelf process of carbon capture has problems, including environmental ones, if you do it on a large scale," said Berend Smit, Chancellor's Professor in the departments of chemical and biomolecular engineering and of chemistry at UC Berkeley and a faculty senior scientist in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). "Our calculations show that we can reduce the parasitic energy costs of carbon capture by 30 percent with these types of materials, which should encourage the industry and academics to look at them." Smit and his colleagues at UC Berkeley, LBNL, Rice University and the Electric Power Research Institute (EPRI) in Palo Alto, Calif., who will publish their results online May 27 in advance of publication in the journal Nature Materials, already are integrating their database of materials into power plant design software. "Our database of carbon capture materials is going to be coupled to a model of a full plant design, so if we have a new material, we can immediately see whether this material makes sense for an actual design," Smit said. Guiding new materials research There are potentially millions of materials that can capture carbon dioxide, but it's physically and economically impossible for scientists and engineers to synthesize and test them all, Smit said. Now, a researcher can upload the structure of a proposed material to Smit's website, and the new computer model will calculate whether it offers improved performance over the energy consumption figures of today's best technology for removing carbon. "What is unique about this model is that, for the first time, we are able to guide the direction for materials research and say, ‘here are the properties we want, even if we don't know what the ultimate material will look like,'" said Abhoyjit Bhown, a co-author of the study and a technical executive at EPRI, which conducts research and development for the electric power industry and the public. "Before, people were trying to figure out what materials they should shoot for, and that question was unanswered until now." Fossil fuel-burning power plants, in particular coal-burning units, are a major source of the carbon dioxide that is rapidly warming the planet and altering the climate in ways that could impact crops and water supplies, raise sea level and lead to weather extremes. Even with the move toward alternative, sustainable and low-carbon sources of energy, ranging from solar and wind to hydrothermal, coal- and natural gas-burning power plants are being built at an increasing rate around the world. At some point, Smit said, carbon capture will be the only way to reduce carbon emissions sufficiently to stave off the worst consequences of climate change. Although no commercial power plants currently capture carbon dioxide on a large scale, a few small-scale and pilot plants do, using today's best technology: funneling emissions through a bath of nitrogen-based amines, which grab carbon dioxide from the flue gases. The amines are then boiled to release the CO2. Additional energy is required to compress the carbon dioxide so that it can be pumped underground. The energy needed for this process decreases the amount that can go into making electricity. Calculations show that for a coal-fired power plant, that could amount to approximately 30 percent of total energy generated. Solid materials should be inherently more energy-efficient than amine scrubbing, because the CO2 can be driven off at lower temperatures. But materials differ significantly in how tightly they grab CO2 and how easily they release it. The best process will be a balance between the two, Smit said. Smit and his UC Berkeley group worked with Bhown and EPRI scientists to establish the best criteria for a good carbon capture material, focusing on the energy costs of capture, release and compression, and then developed a computer model to calculate this energy consumption for any material. Smit then obtained a database of 4 million zeolite structures compiled by Rice University scientists and ran the structures through his model. Zeolites are porous materials made of silicon dioxide, the same composition as quartz. The team also computed the energy efficiency of 10,000 MOF structures, which are composites of metals like iron with organic compounds that, together, form a porous structure. That structure has been touted as a way to store hydrogen for fuel or to separate gases during petroleum refining. "The surprise was that we found many materials, some already known but others hypothetical, that could be synthesized" and work more energy efficiently than amines, Smit said. The best materials used 30 percent less energy than the amine process, though future materials may work even better. The computer model will work for structures other than zeolites and MOFs, Smit said. Bhown said that the theoretically best material will probably have a parasitic energy cost of about 10 percent, so processes that use 20 percent or less are more attractive. GPUs dramatically speed calculations Key to the team's success was using graphics processing units (GPUs) instead of standard computer central processing units (CPUs), GPUs reduced each structure's calculation, which involves complex quantum chemistry, from 10 days to 2 seconds. Bhown noted that most people believe that some economic incentives or regulatory frameworks are needed to implement carbon capture, and the EPRI's goal is to help the industry identify the best technologies for doing so. A survey that EPRI conducted recently suggested that developing any new technology would take 10-15 years even with adequate funding. "The collaboration between different parts of the Department of Energy illustrates what can be achieved if researchers working on the most fundamental aspects of carbon capture collaborate with their industry counterparts" says Karma Sawyer, DOE program director. "This study shows how engineering and fundamental science can speed-up the process of discovery and implementation of promising materials ready to test in the field." "The hope is that there is a system set up such that, when someone comes up with a promising material, we can rapidly test it and get it to a readiness level pretty quickly," he said. "We are all excited by this work and look forward to pursuing it further." Other coauthors of the study are graduate students Li-Chiang Lin and Joseph A. Swisher of UC Berkeley; Adam H. Berger of the EPRI; Richard L. Martin, Chris H. Rycroft and Maciej Haranczyk of LBNL's Computational Research Division; post-doctoral fellows Jihan Kim and Kuldeep Jariwala of LBNL's Materials Science Division; and Michael W. Deem of the Departments of Bioengineering and Physics and Astronomy at Rice University. This work has been supported by the Department of Energy through National Energy Technology Laboratory, Advanced Research Projects Agency-Energy (ARPA-E) and Office of Science, and through EPRI's Office of Technology Innovation. Smit is also director of the Department of Energy-funded Energy Frontier Research Center at UC Berkeley. Related information: Carbon capture materials website Electric Power Research Institute To read more news stories from UC Berkeley, visit us at the Berkeley NewsCenter.

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RV: Recovering water from tailings ponds

 

 

De: Justi [mailto:kraneuspeladen@gmail.com]
Enviado el: martes, 29 de mayo de 2012 11:18
Para: kraneuspeladen@gmail.com
Asunto: RV: Recovering water from tailings ponds

 

 

 

Fuente: University of Alberta ExpressNews
Expuesto el: lunes, 28 de mayo de 2012 23:27
Autor: University of Alberta ExpressNews
Asunto: Recovering water from tailings ponds

 

By Alexandria EldridgeMay 28, 2012 UAlberta researcher Tariq Siddique with the experimental columns in his lab that were used to incubate tailings samples and observe densification. (Edmonton) As Alberta faces increasing pressure to make the oil industry more sustainable, one U of A researcher may have found a natural solution to a problem that has been plaguing oil companies for years. Tariq Siddique, an assistant professor in the Department of Renewable Resources and principal investigator with a U of A oilsands densification group led by biological sciences researcher Julia Foght, says he and his team are finding that microbes could be used to increase the amount of water recovered from tailings ponds. When oilsands are processed, tailings are the materials left over. They include water, clay particles, unrecovered bitumen, and residual solvents that are used during the process of refining oil. This leftover material is dumped into tailings ponds where it can take three to five years for the water to separate from the clay particles. Even then, further settling requires decades. “According to the rules and regulations, [companies] are required to recycle 85 to 90 per cent of the water that they use. If [tailings] don’t settle quickly, they are not able to recover more water,” explained Siddique, adding that although some companies are using polymers to quicken the densification process and meet the requirements, the future environmental implications of this are unknown. Siddique and his collaborators have found a natural way to speed up the settling process—they discovered that microorganisms in tailings ponds degrade hydrocarbons, even complex hydrocarbons, from residual solvents and leftover bitumen, which rids tailings of these contaminants. “Where microbial activity is more, we have seen more densification, more settling of clay particles,” he said. “In this case … with a natural process, you are able to settle the clay quickly [and] you will recover more water for reuse in the extraction process.” Because more microbial activity means more densification, Siddique has been conducting studies using a small-scale bioreactor in which he feeds organic waste to microbes to grow the population, hoping to accelerate densification. In the lab, his team observed about 20 per cent water release within static columns, while in the bioreactor, they observed about 40 per cent water release. “We were thinking that if you construct a kind of bioreactor, feeding microbes with some agricultural waste products, you can increase the microbial population to accelerate densification.” However, there is a potential drawback to an increased microbial population—this process of hydrocarbon breakdown brings greenhouse gas emissions, particularly methane. Siddique says it can be turned into a positive source of energy. “You can trap and use [it],” he said. “Otherwise, any unrecovered hydrocarbons—humans won’t be able to utilize those. But if you can transform it into methane, you can use those.” Siddique has also developed a kinetic model in order to predict how much greenhouse gas will be produced depending on the amount of hydrocarbons in tailings, which could be used to calculate the emissions of oil companies and help in developing regulations to mitigate these emissions. “If we know the concentration of those hydrocarbons in the tailings, we can predict the greenhouse gas emissions,” he said. “We now have some basic fundamental knowledge about the greenhouse gas emission process—what the source is, what type of contaminants are degradable—and who the key players are.” Tailings ponds cover about 170 square kilometres of land in Alberta.

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RV: Computer model pinpoints prime materials for efficient carbon capture

Fuente: UC Berkeley NewsCenter » Category: Science
Expuesto el: domingo, 27 de mayo de 2012 18:00
Autor: Robert Sanders
Asunto: Computer model pinpoints prime materials for efficient carbon capture

 

BERKELEY — When power plants begin capturing their carbon emissions to reduce greenhouse gases – and to most in the electric power industry, it’s a question of when, not if – it will be an expensive undertaking. Coal-fired power plant. Current technologies would use about one-third of the energy generated by the plants – what’s called “parasitic energy” – and, as a result, substantially drive up the price of electricity. But a new computer model developed by University of California, Berkeley, chemists shows that less expensive technologies are on the horizon. They will use new solid materials like zeolites and metal oxide frameworks (MOFs) that more efficiently capture carbon dioxide so that it can be sequestered underground. “The current on-the-shelf process of carbon capture has problems, including environmental ones, if you do it on a large scale,” said Berend Smit, Chancellor’s Professor in the departments of chemical and biomolecular engineering and of chemistry at UC Berkeley and a faculty senior scientist in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). “Our calculations show that we can reduce the parasitic energy costs of carbon capture by 30 percent with these types of materials, which should encourage the industry and academics to look at them.” Smit and his colleagues at UC Berkeley, LBNL, Rice University and the Electric Power Research Institute (EPRI) in Palo Alto, Calif., who will publish their results online May 27 in advance of publication in the journal Nature Materials, already are integrating their database of materials into power plant design software. “Our database of carbon capture materials is going to be coupled to a model of a full plant design, so if we have a new material, we can immediately see whether this material makes sense for an actual design,” Smit said. Guiding new materials research There are potentially millions of materials that can capture carbon dioxide, but it’s physically and economically impossible for scientists and engineers to synthesize and test them all, Smit said. Now, a researcher can upload the structure of a proposed material to Smit’s website, and the new computer model will calculate whether it offers improved performance over the energy consumption figures of today’s best technology for removing carbon. One of the 50 best zeolite structures for capturing carbon dioxide. Zeolite is a porous solid made of silicon dioxide, or quartz. In the model, the red balls are oxygen, the tan balls are silicon. The blue-green area is where carbon dioxide prefers to nestle when it adsorbs. (Berend Smit laboratory, UC Berkeley) “What is unique about this model is that, for the first time, we are able to guide the direction for materials research and say, ‘here are the properties we want, even if we don’t know what the ultimate material will look like,’” said Abhoyjit Bhown, a co-author of the study and a technical executive at EPRI, which conducts research and development for the electric power industry and the public. “Before, people were trying to figure out what materials they should shoot for, and that question was unanswered until now.” Fossil fuel-burning power plants, in particular coal-burning units, are a major source of the carbon dioxide that is rapidly warming the planet and altering the climate in ways that could impact crops and water supplies, raise sea level and lead to weather extremes. Even with the move toward alternative, sustainable and low-carbon sources of energy, ranging from solar and wind to hydrothermal, coal- and natural gas-burning power plants are being built at an increasing rate around the world. At some point, Smit said, carbon capture will be the only way to reduce carbon emissions sufficiently to stave off the worst consequences of climate change. Although no commercial power plants currently capture carbon dioxide on a large scale, a few small-scale and pilot plants do, using today’s best technology: funneling emissions through a bath of nitrogen-based amines, which grab carbon dioxide from the flue gases. The amines are then boiled to release the CO2. Additional energy is required to compress the carbon dioxide so that it can be pumped underground. The energy needed for this process decreases the amount that can go into making electricity. Calculations show that for a coal-fired power plant, that could amount to approximately 30 percent of total energy generated. Solid materials should be inherently more energy-efficient than amine scrubbing, because the CO2 can be driven off at lower temperatures. But materials differ significantly in how tightly they grab CO2 and how easily they release it. The best process will be a balance between the two, Smit said. Smit and his UC Berkeley group worked with Bhown and EPRI scientists to establish the best criteria for a good carbon capture material, focusing on the energy costs of capture, release and compression, and then developed a computer model to calculate this energy consumption for any material. Smit then obtained a database of 4 million zeolite structures compiled by Rice University scientists and ran the structures through his model. Zeolites are porous materials made of silicon dioxide, the same composition as quartz. The team also computed the energy efficiency of 10,000 MOF structures, which are composites of metals like iron with organic compounds that, together, form a porous structure. That structure has been touted as a way to store hydrogen for fuel or to separate gases during petroleum refining. “The surprise was that we found many materials, some already known but others hypothetical, that could be synthesized” and work more energy efficiently than amines, Smit said. The best materials used 30 percent less energy than the amine process, though future materials may work even better. The computer model will work for structures other than zeolites and MOFs, Smit said. Bhown said that the theoretically best material will probably have a parasitic energy cost of about 10 percent, so processes that use 20 percent or less are more attractive. GPUs dramatically speed calculations Key to the team’s success was using graphics processing units (GPUs) instead of standard computer central processing units (CPUs), GPUs reduced each structure’s calculation, which involves complex quantum chemistry, from 10 days to 2 seconds. Bhown noted that most people believe that some economic incentives or regulatory frameworks are needed to implement carbon capture, and the EPRI’s goal is to help the industry identify the best technologies for doing so. A survey that EPRI conducted recently suggested that developing any new technology would take 10-15 years even with adequate funding. “The collaboration between different parts of the Department of Energy illustrates what can be achieved if researchers working on the most fundamental aspects of carbon capture collaborate with their industry counterparts” says Karma Sawyer, DOE program director. “This study shows how engineering and fundamental science can speed-up the process of discovery and implementation of promising materials ready to test in the field.” “The hope is that there is a system set up such that, when someone comes up with a promising material, we can rapidly test it and get it to a readiness level pretty quickly,” he said. “We are all excited by this work and look forward to pursuing it further.” Other coauthors of the study are graduate students Li-Chiang Lin and Joseph A. Swisher of UC Berkeley; Adam H. Berger of the EPRI; Richard L. Martin, Chris H. Rycroft and Maciej Haranczyk of LBNL’s Computational Research Division; post-doctoral fellows Jihan Kim and Kuldeep Jariwala of LBNL’s Materials Science Division; and Michael W. Deem of the Departments of Bioengineering and Physics and Astronomy at Rice University. This work has been supported by the Department of Energy through National Energy Technology Laboratory, Advanced Research Projects Agency—Energy (ARPA-E) and Office of Science, and through EPRI’s Office of Technology Innovation. Smit is also director of the Department of Energy-funded Energy Frontier Research Center at UC Berkeley. Related information: Carbon capture materials website Electric Power Research Institute

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