Friday, July 10, 2009

THOSE UNSURE OF OWN IDEAS MORE RESISTANT TO VIEWS OF OTHERS

0 comentarios

We swim in a sea of information, but filter out most of what we see and hear. A new analysis of data from dozens of studies sheds new light on how we choose what we do and do not hear. The study found that while people tend to avoid information that contradicts what they already think or believe, certain factors can cause them to seek out, or at least consider, other points of view.

The analysis, reported in Psychological Bulletin, published by the American Psychological Association, was led by researchers at the University of Illinois and the University of Florida, and included data from 91 studies involving nearly 8,000 participants. It puts to rest a longstanding debate over whether people actively avoid information that contradicts what they believe, or whether they are simply exposed more often to ideas that conform to their own because they tend to be surrounded by like-minded people.

"We wanted to see exactly across the board to what extent people are willing to seek out the truth versus just stay comfortable with what they know," said University of Illinois psychology professor Dolores Albarracín, who led the study with University of Florida researcher William Hart. The team also included researchers from Northwestern University and Ohio University.

The studies they reviewed generally asked participants about their views on a given topic and then allowed them to choose whether they wanted to view or read information supporting their own or an opposing point of view.

The researchers found that people are about twice as likely to select information that supports their own point of view (67 percent) as to consider an opposing idea (33 percent). Certain individuals, those with close-minded personalities, are even more reluctant to expose themselves to differing perspectives, Albarracín said. They will opt for the information that corresponds to their views nearly 75 percent of the time.

The researchers also found, not surprisingly, that people are more resistant to new points of view when their own ideas are associated with political, religious or ethical values.

"If you are really committed to your own attitude – for example, if you are a very committed Democrat – you are more likely to seek congenial information, that is, information that corresponds with your views," Albarracín said. "If the issues concern moral values or politics, about 70 percent of the time you will choose congenial information, versus about 60 percent of the time if the issues are not related to values."

Perhaps more surprisingly, people who have little confidence in their own beliefs are less likely to expose themselves to contrary views than people who are very confident in their own ideas, Albarracín said.

Certain factors can also induce people to seek out opposing points of view, she said. Those who may have to publicly defend their ideas, such as politicians, for example, are more motivated to learn about the views of those who oppose them. In the process, she said, they sometimes find that their own ideas evolve.

People are also more likely to expose themselves to opposing ideas when it is useful to them in some way, Albarracín said.

"If you're going to buy a house and you really like the house, you're still going to have it inspected," she said. Similarly, no matter how much you like your surgeon, you may seek out a second opinion before scheduling a major operation, she said.

"For the most part it seems that people tend to stay with their own beliefs and attitudes because changing those might prevent them from living the lives they're living," Albarracín said. "But it's good news that one out of three times, or close to that, they are willing to seek out the other side."

(Photo: L. Brian Stauffer)

University of Illinois

SPANISH SCIENTISTS DEVELOP ECHO-LOCATION IN HUMANS

0 comentarios

A team of researchers from the University of Alcalá de Henares (UAH) has shown scientifically that human beings can develop echolocation, the system of acoustic signals used by dolphins and bats to explore their surroundings. Producing certain kinds of tongue clicks helps people to identify objects around them without needing to see them, something which would be especially useful for the blind.

"In certain circumstances, we humans could rival bats in our echolocation or biosonar capacity", Juan Antonio Martínez, lead author of the study and a researcher at the Superior Polytechnic School of the UAH, tells SINC. The team led by this scientist has started a series of tests, the first of their kind in the world, to make use of human beings' under-exploited echolocation skills.

In the first study, published in the journal Acta Acustica united with Acustica, the team analyses the physical properties of various sounds, and proposes the most effective of these for use in echolocation. "The almost ideal sound is the 'palate click, a click made by placing the tip of the tongue on the palate, just behind the teeth, and moving it quickly backwards, although it is often done downwards, which is wrong", Martínez explains.

The researcher says that palate clicks "are very similar to the sounds made by dolphins, although on a different scale, as these animals have specially-adapted organs and can produce 200 clicks per second, while we can only produce three or four". By using echolocation, "which is three-dimensional, and makes it possible to 'see' through materials that are opaque to visible radiation" it is possible to measure the distance of an object based on the time that elapses between the emission of a sound wave and an echo being received of this wave as it is reflected from the object.

In order to learn how to emit, receive and interpret sounds, the scientists are developing a method that uses a series of protocols. This first step is for the individual to know how to make and identify his or her own sounds (they are different for each person), and later to know how to use them to distinguish between objects according to their geometrical properties "as is done by ships' sonar".

Some blind people had previously taught themselves how to use echolocation "by trial and error". The best-known cases of these are the Americans Daniel Kish, the only blind person to have been awarded a certificate to act as a guide for other blind people, and Ben Underwood, who was considered to be the world's best "echolocator" until he died at the start of 2009.

However, no special physical skills are required in order to develop this skill. "Two hours per day for a couple of weeks are enough to distinguish whether you have an object in front of you, and within another two weeks you can tell the difference between trees and a pavement", Martínez tells SINC.

The scientist recommends trying with the typical "sh" sound used to make someone be quiet. Moving a pen in front of the mouth can be noticed straightaway. This is a similar phenomenon to that when travelling in a car with the windows down, which makes it possible to "hear" gaps in the verge of the road.

The next level is to learn how to master the "palate clicks". To make sure echoes from the tongue clicks are properly interpreted, the researchers are working with a laser pointer, which shows the part of an object at which the sound should be aimed.

Martínez has told SINC that his team is now working to help deaf and blind people to use this method in the future, because echoes are not only perceived by their ear, but also through vibrations in the tongue and bones. "For these kinds of people in particular, and for all of us in general, this would be a new way of perceiving the world".

Another of the team's research areas involves establishing the biological limits of human echolocation ability, "and the first results indicate that detailed resolution using this method could even rival that of sight itself". In fact, the researchers started out by being able to tell if there was someone standing in front of them, but now can detect certain internal structures, such as bones, and even "certain objects inside a bag".

The scientists recognise that they are still at the very early stages, but the possibilities that would be opened up with the development of echolocation in humans are enormous. This technique will be very practical not only for the blind, but also for professionals such as firemen (enabling them to find exit points through smoke), and rescue teams, or simply people lost in fog.

A better understanding of the mental mechanisms used in echolocation could also help to design new medical imaging technologies or scanners, which make use of the great penetration capacity of clicks. Martínez stresses that these sounds "are so penetrating that, even in environments as noisy as the metro, one can sense discontinuities in the platform or tunnels".

(Photo: SINC)

Fundación Española para la Ciencia y la Tecnología

NEW FOSSIL PRIMATE SUGGESTS COMMON ASIAN ANCESTOR, CHALLENGES PRIMATES SUCH AS 'IDA'

0 comentarios

According to new research published online in the Proceedings of the Royal Society B (Biological Sciences) on July 1, 2009, a new fossil primate from Myanmar (previously known as Burma) suggests that the common ancestor of humans, monkeys and apes evolved from primates in Asia, not Africa as many researchers believe.

A major focus of recent paleoanthropological research has been to establish the origin of anthropoid primates (monkeys, apes and humans) from earlier and more primitive primates known as prosimians (lemurs, tarsiers and their extinct relatives). Prior to recent discoveries in China, Thailand, and Myanmar, most scientists believed that anthropoids originated in Africa. Earlier this year, the discovery of the fossil primate skeleton known as "Ida" from the Messel oil shale pit in Germany led some scientists to suggest that anthropoid primates evolved from lemur-like ancestors known as adapiforms.

According to Dr. Chris Beard–– a paleontologist at Carnegie Museum of Natural History in Pittsburgh, Pennsylvania and a member of the international team of researchers behind the Myanmar anthropoid findings––the new primate, Ganlea megacanina, shows that early anthropoids originated in Asia rather than Africa. These early Asian anthropoids differed radically from adapiforms like Ida, indicating that Ida is more closely related to modern lemurs than it is to monkeys, apes and humans.

The 38-million-year-old Ganlea megacanina fossils, excavated at multiple sites in central Myanmar, belong to a new genus and species. The name of the new species refers to a small village, Ganle, near the original site where the fossils were found, and the greatly enlarged canine teeth that distinguish the animal from closely related primates. Heavy dental abrasion indicates that Ganlea megacanina used its enlarged canine teeth to pry open the hard exteriors of tough tropical fruits in order to extract the nutritious seeds contained inside.

"This unusual type of feeding adaptation has never been documented among prosimian primates, but is characteristic of modern South American saki monkeys that inhabit the Amazon Basin," says Dr. Beard. "Ganlea shows that early Asian anthropoids had already assumed the modern ecological role of modern monkeys 38 million years ago."

Ganlea and its closest relatives belong to an extinct family of Asian anthropoid primates known as the Amphipithecidae. Two other amphipithecids, Pondaungia and Myanmarpithecus, were previously discovered in Myanmar, while a third, named Siamopithecus, had been found in Thailand. A detailed analysis of their evolutionary relationships shows that amphipithecids are closely related to living anthropoids and that all of the Burmese amphipithecids evolved from a single common ancestor. Some scientists had previously argued that amphipithecids were not anthropoids at all, being more closely related to the lemur-like adapiforms.

The discovery of Ganlea strongly supports the idea that amphipithecids are anthropoids, because adapiforms never evolved the features that are necessary to become specialized seed predators. Indeed, all of the Burmese amphipithecids appear to have been specialized seed predators, filling the same ecological niche occupied by modern pitheciine monkeys in the Amazon Basin of South America. During the Eocene when Ganlea and other amphipithecids were living in Myanmar, they inhabited a tropical floodplain that was very similar to the environment of the modern Amazon Basin.

(Photo: Mark A. Klingler/Carnegie Museum of Natural History)

Carnegie Museum of Natural History

SUPER-SIZE DEPOSITS OF FROZEN CARBON THREAT TO CLIMATE CHANGE

0 comentarios

The vast amount of carbon stored in the arctic and boreal regions of the world is more than double that previously estimated, according to a study published recently.

The amount of carbon in frozen soils, sediments and river deltas (permafrost) raises new concerns over the role of the northern regions as future sources of greenhouse gases.

"We now estimate the deposits contain over 1.5 trillion tons of frozen carbon, about twice as much carbon as contained in the atmosphere", said Dr. Charles Tarnocai, Agriculture and Agri-Food Canada, Ottawa, and lead author.

Dr. Pep Canadell, Executive Director of the Global Carbon Project at CSIRO, Australia, and co-author of the study says that the existence of these super-sized deposits of frozen carbon means that any thawing of permafrost due to global warming may lead to significant emissions of the greenhouse gases carbon dioxide and methane.

Carbon deposits frozen thousands of years ago can easily break down when permafrost thaws releasing greenhouse gases to the atmosphere, according to another recent study by some of the same authors.

"Radioactive carbon dating shows that most of the carbon dioxide currently emitted by thawing soils in Alaska was formed and frozen thousands of years ago. The carbon dating demonstrates how easily carbon decomposes when soils thaw under warmer conditions," said Professor Ted Schuur, University of Florida and co-author of the paper.

The authors point out the large uncertainties surrounding the extent to which permafrost carbon thawing could further accelerate climate change.

"Permafrost carbon is a bit of a wildcard in the efforts to predict future climate change," said Dr Canadell. "All evidence to date shows that carbon in permafrost is likely to play a significant role in the 21st century climate given the large carbon deposits, the readiness of its organic matter to release greenhouse gases when thawed, and the fact that high latitudes will experience the largest increase in air temperature of all regions."

Carbon in permafrost is found largely in northern regions including Canada, Greenland, Kazakhstan, Mongolia, Russia, Scandinavia and USA.

The carbon assessment is published this week in the journal of "Global Biogeochemical Cycles" of the American Geophysical Union, and the radiocarbon study was recently published in the journal of Nature.

(Photo: Edward A. G. Schuur)

Global Carbon Project

DYNASTY: INFLUENZA VIRUS IN 1918 AND TODAY

0 comentarios

In an article published online on June 29 by the New England Journal of Medicine, authors Anthony S. Fauci, M.D., Jeffery K. Taubenberger, M.D., Ph.D., and David M. Morens, M.D., argue that we have lived in an influenza pandemic era since 1918, and they describe how the novel 2009 H1N1 virus now circling the globe is yet another manifestation of this enduring viral family.

"The 1918-1919 influenza pandemic was a defining event in the history of public health," says NIAID Director Dr. Fauci. "The legacy of that pandemic lives on in many ways, including the fact that the descendents of the 1918 virus have continued to circulate for nine decades."

Influenza viruses have eight genes, two of which code for virus surface proteins—hemagglutinin (H) and neuraminidase (N)—that allow the virus to enter a host cell and spread from cell to cell. There are 16 H subtypes and 9 N subtypes, and, therefore, 144 possible HN combinations. However, only three (H1N1, H2N2 and H3N2) have ever been found in influenza viruses that are fully adapted to infect humans. Other combinations, such as avian influenza H5N1, occasionally infect people, but they are bird viruses, not human viruses.

"The eight influenza genes can be thought of as players on a team: Certain combinations of players may arise through chance and endow the virus with new abilities, such as the ability to infect a new type of host," says Dr. Morens, Senior Advisor to the NIAID Director. That is likely what happened to spark the 1918 pandemic, he adds. Scientists have shown that the founding virus was an avian-like virus. The virus had a novel set of eight genes and—through still-unknown mechanisms—gained the ability to infect people and spread readily from person to person.

Not only did the 1918 H1N1 virus set off an explosive pandemic in which tens of millions died, during the pandemic the virus was transmitted from humans to pigs, where—as it does in people—it continues to evolve to this day. "Ever since 1918, this tenacious virus has drawn on a bag of evolutionary tricks to survive in one form or another…and to spawn a host of novel progeny viruses with novel gene constellations, through the periodic importation or exportation of viral genes," write the NIAID authors.

"All human-adapted influenza A viruses of today—both seasonal variations and those that caused more dramatic pandemics—are descendents, direct or indirect, of that founding virus," notes Dr. Taubenberger, Senior Investigator in NIAID's Laboratory of Infectious Diseases. "Thus we can be said to be living in a pandemic era that began in 1918."

How exactly do new influenza gene teams make the leap from aquatic birds to a new host, such as people or other mammals? What factors determine whether infection in a new host yields a dead-end infection or sustained, human-to-human transmission, as happened in 1918? Research on such topics is intense, but at this time definitive answers remain elusive, notes Dr. Morens.

It is known that the human immune system mounts a defense against the influenza virus's H and N proteins, primarily in the form of antibodies. But as population-wide immunity to any new variant of flu arises, the virus reacts by changing in large and small ways that make it more difficult for antibodies to recognize it. For nearly a century, then, the immune system has been engaged in a complicated pas de deux with the 1918 influenza virus and its progeny, say the NIAID authors. The partners in this dance are linked in an endless effort to take the lead from the other.

While the dynasty founded by the virus of 1918 shows little evidence of being overthrown, the NIAID authors note that there may be some cause for optimism. When viewed through a long lens of many decades, it does appear that successive pandemics and outbreaks caused by later generations of the 1918 influenza dynasty are decreasing in severity, notes Dr. Morens. This is due in part to advances in medicine and public health measures, he says, but this trend also may reflect viral evolutionary pathways that favor increases in the virus's ability to spread from host to host, combined with decreases in its tendency to kill those hosts.

"Although we must be prepared to deal with the possibility of a new and clinically severe influenza pandemic caused by an entirely new virus, we must also understand in greater depth, and continue to explore, the determinants and dynamics of the pandemic era in which we live," conclude the authors.

(Photo: NIAID)

NIAID

DINO TOOTH SHEDS NEW LIGHT ON ANCIENT RIDDLE

0 comentarios

A study led by the University of Leicester, has found evidence that the duck-billed dinosaurs- the Hadrosaurs- had a unique way of eating, unlike any living creature today.

Working with researchers from the Natural History Museum, the study uses a new approach to analyse the feeding mechanisms of dinosaurs and understand their place in the ecosystems of tens of millions of years ago. The results are published today in the Proceedings of the National Academy of Sciences.

Palaeontologist Mark Purnell of the University of Leicester Department of Geology, who led the research, said: "For millions of years, until their extinction at the end of the Cretaceous, duck-billed dinosaurs – or hadrosaurs - were the World's dominant herbivores. They must have been able to break down their food somehow, but without the complex jaw joint of mammals they would not have been able to chew in the same way, and it is difficult to work out how they ate. It is also unclear what they ate: they might have been grazers, cropping vegetation close to the ground - like today's cows and sheep - or browsers, eating leaves and twigs - more like deer or giraffes. Not knowing the answers to these questions makes it difficult to understand Late Cretaceous ecosystems and how they were affected during the major extinction event 65 million years ago.

"Our study uses a new approach based on analysis of the microscopic scratches that formed on hadrosaur's teeth as they fed, tens of millions of years ago. The scratches have been preserved intact since the animals died. They can tell us precisely how hadrosaur jaws moved, and the kind of food these huge herbivores ate, but nobody has tried to analyse them before."

The researchers say that the scratches reveal that the movements of hadrosaur teeth were complex and involved up and down, sideways and front to back motion. According to Paul Barrett palaeontologist at the Natural History Museum "this shows that hadrosaurs did chew, but in a completely different way to anything alive today. Rather than a flexible lower jaw joint, they had a hinge between the upper jaws and the rest of the skull. As they bit down on their food the upper jaws were forced outwards, flexing along this hinge so that the tooth surfaces slid sideways across each other, grinding and shredding food in the process".

The scratch patterns provide confirmation of a theory of hadrosaur chewing first proposed 25 years ago, and provides new insights into their ecology, say the researchers.

The research also sheds light on what the dinosaurs ate. Vince Williams of the University of Leicester said: "Although the first grasses had evolved by the Late Cretaceous they were not common and it is most unlikely that grasses formed a major component of hadrosaur diets. We can tell from the scratches that the hadrosaur's food either contained small particles of grit, normal for vegetation cropped close to the ground, or, like grass, contained microscopic granules of silica. We know that horsetails were a common plant at the time and have this characteristic; they may well have been an important food for hadrosaurs".

One of the big surprises of this study is that so much information about such large animals can be gleaned from such a tiny patch of tooth. "By looking at the pattern of scratches in an area that is only about as wide as a couple of human hairs we can work out how and what these huge herbivores were eating" notes Williams. "And because we can analyse single teeth, rather than whole skeletons, the technique has the potential to tell us a lot more about dinosaur feeding and the ecosystems in which they lived."

(Photo: Vince Williams, University of Leicester)

University of Leicester

BABOONS, HUMANS ADAPTED SIMILARLY TO MALARIA

0 comentarios

In humans, subtle variation in one particular gene that controls whether a protein on the surface of red blood cells gets made or not literally spells the difference between susceptibility or resistance to one form of malaria. That’s because the blood protein serves as the entry point for Plasmodium vivax, one of several malaria-causing parasites that infect humans.

Now, researchers at the Duke Institute for Genome Sciences & Policy report that variation in precisely the same regulatory gene also influences baboons’ chances of getting sick, by ratcheting their susceptibility to another, closely related parasite up or down.

“It’s a nice example of how – in the vastness of the genome – the same gene was modified in the same way in two different species to produce the same kind of resistance,” says Greg Wray, director of the IGSP’s Center for Evolutionary Genomics. “That’s a pretty remarkable thing when you think of all the different ways malaria resistance might have evolved.”

The findings, which appeared online in Nature on June 24, also mark a turning point in primate research: they are the first to connect any functionally important genetic variation in wild primates to complex, real-life consequences for the animals.

The yellow baboons in question live in Kenya’s Amboseli National Park and have been the subject of ongoing observation for nearly 40 years, making them one of the best-studied wild mammal populations in the world from a behavioral and life history standpoint.

“It used to be that our work was limited to ‘skin-out’ biology,” says Susan Alberts, an associate professor of biology and IGSP member who has been recording the habits of the baboons for the last 25 years. Today, thanks to a growing library of sequenced primate genomes including our own, scientists can begin to delve deeper.

Graduate student Jenny Tung spent three summers out on the East African savanna, watching the baboons, collecting their DNA-laden feces, and with the help of an expert team of Kenyan field assistants, very carefully drawing blood from darted animals. Successfully darting baboons is no small feat, Tung said. You have to be within meters of the animal you are targeting, and at the same time make sure that none of the baboons catch you in the act. If they did, it would send the troop running and screaming and, in technical terms, “really mess up the field data.” In the evenings, Tung processed and stored her hard-won samples in a makeshift refrigerator before shipping them off to Duke.

Once back at the lab, Tung found something in those blood samples that came as a surprise despite all the years of study. More than half of the Amboseli baboons -- some 60 percent -- were infected with the malaria-like parasite known as Hepatocystis.

“We had no idea so many of them were carrying this parasite,” Alberts says. For years, researchers have tracked the baboons for any signs of injury or illness. But although the infection probably compromises the animals, they don’t develop cyclical fever spikes or other immediately obvious symptoms like humans with malaria do.

In search of a genetic basis for differences in the baboons’ vulnerability to infection, the researchers zeroed in on the DNA sequence surrounding the DARC gene, the same region that has been traced to malaria protection among people. Although the specifics differ from those in humans, they found that a single letter change to the genetic code -- a switch from an A to a G -- lends some baboons the ability to better fend off infection. In fact, they show, one G is good, but two are even better.

Further analysis of the baboons’ blood and in cell culture confirmed that the variants influence infection rates through changes in the activity of the DARC gene. Comparison of the Amboseli baboon sequences to two other populations also showed that the DNA sequence has undergone a relatively rapid rate of evolutionary change, the mark of natural selection for malaria resistance.

The newfound parallels between baboons and humans bring the long history of conflict between parasite and host into high relief. “It’s a struggle out there,” Alberts says. “We often think of malaria as a contemporary problem, but it’s a deep part of our history.”

The study also shows the power of coupling genomics with dedicated fieldwork. “Part of what we want to do is push the envelope and show that this is doable,” Wray says. With the proof of principle in hand, the next big challenge is to begin to unravel the genomic differences that may be responsible for fuzzier behavioral traits, such as social status or aggression, he added.

“It’s getting easier and easier to generate genetic data,” Tung says. “But it’s never going to be easy to have long-term field data -- especially for primates. It takes years and years before you see the fruit of those labors. We’re just at the point where it’s going to really start paying off.”

(Photo: Zina Deretsky, National Science Foundation)

Duke Institute for Genome Sciences & Policy

THE FIRST GLOBAL MAP OF AMMONIA EMISSIONS MEASURED FROM SPACE

0 comentarios

The first complete map of global ammonia emissions has recently been achieved using to satellite data. It reveals an underestimation of some of the ammonia concentrations detected by current inventories, and identifies new hotspots.

This work, carried out by a team from LATMOS-IPSL (CNRS/UPMC/UVSQ) in collaboration with Belgian researchers from the Université Libre de Bruxelles, was facilitated by the infrared measurements of the French IASI instrument, part of the MetOp meteorological satellite developed by CNES. These results were published online in Nature Geoscience on 21 June 2009.

Ammonia (NH3) contributes significantly to the formation of the particles that give rise to pollution episodes. It mainly emanates from the use of agricultural fertilizers and increasingly intensified livestock breeding practices. Ammonia is the least well-understood pollutant regulated by European Directives on air quality. Mapping of its emissions are imprecise and systematic global monitoring of this compound is difficult. Once emitted, ammonia only remains in the atmosphere for a short period but triggers a cascade of environmental effects. At a local level, high ammonia concentrations affect fauna, flora and air quality.

Although the IASI instrument (part of the MetOp meteorological satellite) was not initially intended to detect ammonia in the Earth's atmosphere, researchers developed a methodology that could isolate the signature of ammonia from its background signal. By filtering the data and accumulating them continuously over a one-year observation period (more than a million measurements per day, with two passes over each part of the globe), the scientists were able to generate maps of its concentrations and to compare them with recent atmospheric models.

This work has demonstrated an underestimation of the ammonia emissions supplied by current inventories in agricultural valleys of the northern hemisphere, and particularly in the USA (the regions of San Joaquin in California and Snake River Valley in Idaho) and Europe (the Po and Ebre valleys). The most marked differences were found in Central Asia, with the identification of some sources not mentioned in current inventories.

(Photo: © Image MODIS © L. Gonzalez/C. Deroo LOA; Image IASI © ULB & INSU-CNRS)

CNRS

HIPS FIREPROOF COATINGS CAN REALLY TAKE THE HEAT

0 comentarios

HIPS coatings can withstand temperatures of over 1000°C compared to current commercial coatings used on building materials and structures which break down at between 150-250°C.

HIPS coatings contain an inorganic geopolymer resin, and a small component of polymer additives.

Project leader, Dr Damian Fullston of CSIRO Materials Science and Engineering, says CSIRO is seeking coatings manufacturers interested in partnering with CSIRO to customise HIPS to meet product specifications for selected applications.

“They are not only fire-, blast- and acid-resistant, they are also strong, castable, sprayable, and extrudable, making their potential uses almost limitless.”“Geopolymers are an emerging class of ceramic-like inorganic polymers produced at room temperatures that have the potential to transform the building products industry,” Dr Fullston says.

“They are not only fire-, blast- and acid-resistant, they are also strong, castable, sprayable, and extrudable, making their potential uses almost limitless.”

“The polymer additives in HIPS improve the flexibility and waterproofing properties, and provide stronger adhesion, which are important properties for a coating.”

HIPS has the potential to form thin fireproof coatings on timbers such as weatherboards, and on metals such as structural or galvanised steel. It can also protect brickwork, either as a thin coating or as a render. HIPS can be applied by spray equipment, roller or brush, and cures from ambient temperature to below 90°C.

As water-based products, HIPS coatings are free of volatile organic compounds, do not burn or produce heat, and do not release smoke or toxic chemicals at temperatures up to 1200°C.

Geopolymers are cost-competitive, since they are made from readily available raw materials. They can also be derived from industrial by-products such as flyash and blast furnace slag. They can be cheaper than organic resins and coloured with pigments or dyes.

The strength of HIPS materials is comparable with that of phenolic resins in heat-sensitive applications, but HIPS retains higher strength at higher temperatures. HIPS formulations are tailored to be interchangeable with phenolic resins, and have higher fatigue resistance than normal phenolics.

CSIRO also sees potential for the manufacture of fireproof wood composites and fire seals from HIPS technology, but has not fully explored these applications to date.

(Photo: CSIRO)

CSIRO

Followers

Archive

 

Selected Science News. Copyright 2008 All Rights Reserved Revolution Two Church theme by Brian Gardner Converted into Blogger Template by Bloganol dot com