Diamond will always be a woman’s best friend but the gemstone is no longer the world’s hardest material, according to scientists.
Diamond: It is specifically renowned as a material with superlative physical qualities.
Instead, a rare natural substance, called lonsdaleite, which is made from carbon atoms just like diamond, has emerged as 58 per cent harder than the gemstone, according to a report in the New Scientist.
An international team, led by Zicheng Pan at Shanghai Jiao Tong University, simulated how atoms in two substances believed to have promise as very hard materials would respond to the stress of a finely tipped probe pushing down on them.
The simulation revealed that the first one, wurtzite boron nitride, withstood 18 per cent more stress than diamond, while the second, the mineral lonsdaleite, 58 per cent more.
Rare mineral lonsdaleite is sometimes formed when meteorites containing graphite hit Earth, while wurtzite boron nitride is formed during volcanic eruptions that produce very high temperatures and pressures.
If confirmed, however, wurtzite boron nitride may turn out most useful of the two, because it is stable in oxygen at higher temperatures than diamond.
And, according to the scientists, this makes it ideal to place on the tips of cutting and drilling tools operating at high temperatures, or as corrosion resistant films on the surface of a space vehicle, for example. Paradoxically, wurtzite boron nitrides hardness appears to come from the flexibility of the bonds between the atoms that make it up.
When its stressed some bonds tend to re-orientate themselves by about 90 to relieve the tension.
Although diamond undergoes a similar process, something about the structure of wurtzite boron nitride makes it nearly 80 per cent stronger after the process takes place, the studys co-author Changfeng Chen of University of Nevada wrote in the Physical Review Letters journal.
Sunday, October 18, 2009
Whats in a Time !!!
TIME is now different from what it once was.
Once a flowing river whose current we passively monitored, time is now more properly understood as something constructed by the brain and personalised by culture. We have relationships with time; we fight it and manipulate it.
Into this arena steps Eva Hoffman with her poetically scientific and austerely titled Time. Published in the New scientist, Hoffman is on an exploration to become intimate with time, motivated by her sense that our interaction with time has changed.
Our societies have become obsessed with time and timekeeping, both in the workplace and at home. Jet travel manipulates our experience of day-night cycles and seasons, while biomedical science races to increase our lifespan yet further. At the other end of the spectrum, new technologies adapt our minds to the ever-briefer scales of micro and nano.
Hoffman covers a lot of ground, from physics (why time flows in only one direction) to biology (the circadian rhythm and sleep) to neuroscience (how temporality is constructed by the brain). She addresses questions of time and consciousness, including the uniquely human ability to envision large vistas of past or future.
Perceived time is illuminated by disease states such as Alzheimer's disease or Korsakoff's syndrome, in which one's time narrative becomes disorganised, and by fantasies and dreams, in which the unconscious brain does not necessarily commit to a temporal narrative at all.
Hoffman also investigates individual differences in how people treat time (those who leave parties early versus those who have to be shooed out at the end) as well as cultural differences (communities in which haste amounts to a breach of ethics, for instance).
A recurring theme is that the human capacity to manipulate our environment ushers in new complexities to the basic biology of time. For example, while other animals age and die on a strict schedule, humans do everything in their power to control that timing. And the book is full of interesting thoughts: consider the different temporal experience of wild blueberry bushes, which live 13,000 years, and mayflies, which fulfil their earthly purpose in a lifespan of hours.
Other animals age and die on a strict schedule, but we humans do all in our power to control that timing
One gap in the book involves the perception of very short time scales - of less than a second - which neuroscientists refer to as time sensation: did he catch my glance at his name tag? Which event happened first, my footfall or the snapping twig? Sub-second time sensation is a fertile area in modern brain research, one that is unlocking fundamental mysteries about perception. However, given the wonderfully vast territory Hoffman covers, I don't expect readers to notice its absence.
The book argues convincingly that our relationship with time is changing drastically, portending real consequences for our quality of life. These considerations lead Hoffman to state that our changing relationship with time amounts to a "paradigm shift comparable to the Copernican or Einsteinian revolutions". I'm not sure the claim is warranted - such claims rarely are more than once a century - but Hoffman is such a good writer that I take the exaggeration merely to be a show of passion for her subject.
The author describes her childhood in Eastern Europe as slow-tempo, and one suspects that only an immigrant's eyes could so clearly detect the "American nervousness" with time: the way Americans squeeze time and fret about it in their "perpetually renewing newness". But she's not necessarily opposed to the American tempo. She acknowledges that the strict, efficient management of time has its merits - for example, knowing how much one's time is worth and asserting one's "temporal rights".
Hoffman is a lyrical writer, and her style is both congenial and calming. She labels herself a chronophobic and a chronophilic, but I see her more as a time connoisseur, sharply attuned to its subtleties. Time is strong both scientifically and sociologically, provoking endless contemplation. One sees that Hoffman desires to understand time - not to pin it lifelessly to a wall, but instead to cherish it.
Profile
David Eagleman is a neuroscientist at Baylor College of Medicine in Houston, Texas
Source : New Scientist
Once a flowing river whose current we passively monitored, time is now more properly understood as something constructed by the brain and personalised by culture. We have relationships with time; we fight it and manipulate it.
Into this arena steps Eva Hoffman with her poetically scientific and austerely titled Time. Published in the New scientist, Hoffman is on an exploration to become intimate with time, motivated by her sense that our interaction with time has changed.
Our societies have become obsessed with time and timekeeping, both in the workplace and at home. Jet travel manipulates our experience of day-night cycles and seasons, while biomedical science races to increase our lifespan yet further. At the other end of the spectrum, new technologies adapt our minds to the ever-briefer scales of micro and nano.
Hoffman covers a lot of ground, from physics (why time flows in only one direction) to biology (the circadian rhythm and sleep) to neuroscience (how temporality is constructed by the brain). She addresses questions of time and consciousness, including the uniquely human ability to envision large vistas of past or future.
Perceived time is illuminated by disease states such as Alzheimer's disease or Korsakoff's syndrome, in which one's time narrative becomes disorganised, and by fantasies and dreams, in which the unconscious brain does not necessarily commit to a temporal narrative at all.
Hoffman also investigates individual differences in how people treat time (those who leave parties early versus those who have to be shooed out at the end) as well as cultural differences (communities in which haste amounts to a breach of ethics, for instance).
A recurring theme is that the human capacity to manipulate our environment ushers in new complexities to the basic biology of time. For example, while other animals age and die on a strict schedule, humans do everything in their power to control that timing. And the book is full of interesting thoughts: consider the different temporal experience of wild blueberry bushes, which live 13,000 years, and mayflies, which fulfil their earthly purpose in a lifespan of hours.
Other animals age and die on a strict schedule, but we humans do all in our power to control that timing
One gap in the book involves the perception of very short time scales - of less than a second - which neuroscientists refer to as time sensation: did he catch my glance at his name tag? Which event happened first, my footfall or the snapping twig? Sub-second time sensation is a fertile area in modern brain research, one that is unlocking fundamental mysteries about perception. However, given the wonderfully vast territory Hoffman covers, I don't expect readers to notice its absence.
The book argues convincingly that our relationship with time is changing drastically, portending real consequences for our quality of life. These considerations lead Hoffman to state that our changing relationship with time amounts to a "paradigm shift comparable to the Copernican or Einsteinian revolutions". I'm not sure the claim is warranted - such claims rarely are more than once a century - but Hoffman is such a good writer that I take the exaggeration merely to be a show of passion for her subject.
The author describes her childhood in Eastern Europe as slow-tempo, and one suspects that only an immigrant's eyes could so clearly detect the "American nervousness" with time: the way Americans squeeze time and fret about it in their "perpetually renewing newness". But she's not necessarily opposed to the American tempo. She acknowledges that the strict, efficient management of time has its merits - for example, knowing how much one's time is worth and asserting one's "temporal rights".
Hoffman is a lyrical writer, and her style is both congenial and calming. She labels herself a chronophobic and a chronophilic, but I see her more as a time connoisseur, sharply attuned to its subtleties. Time is strong both scientifically and sociologically, provoking endless contemplation. One sees that Hoffman desires to understand time - not to pin it lifelessly to a wall, but instead to cherish it.
Profile
David Eagleman is a neuroscientist at Baylor College of Medicine in Houston, Texas
Source : New Scientist
Saturday, October 17, 2009
Fly Fly Butterfly
Rare Butterfly sighted after 100 yrs
Deep within the graveyard of butterflies, there moves a flutter of hope. And the awestruck nature-lover, bewildered at the miraculous triumph, captures a quick moment of the blithe spirits flight for posterity.
Kushal Choudhury, a young lepidopterologist and lecturer Kokrajhar Science College, has spotted a rare breed of swallowtail butterfly considered extinct at Ultapani Reserve Forest. The jungle, under Haltugaon forest division, is notorious for being the deathbed of hundreds these winged creatures.
Choudhury, who has been ing on a butterfly project since 2002
and is researching on swallowtail butterflies for his PhD since 2008, said, ‘‘The Yellow Crested Spangle (Papilio Elephenor Doubleday) was resighted after a long gap of 100 years in Ripu-Chirang Wildlife Sanctuary (RCWS) that extends between 89:554-90:304E and 27:154-26:354N in the Bodoland Territorial Council of western Assam.’’
He added, ‘‘The sanctuary is a transitional zone between Manas Tiger Reserve in the east and Buxa Tiger Reserve (West Bengal) in the west. It also has strong linkages with Bhutan Biological Conservation Complex as it is located just at the foothills of Phipsu Wildlife Sanctuary and Royal Manas National Park of Bhutan.’’
At first, Choudhury believed that it was a mutated spangle butterfly (Papilio protenor) that is similar in size and colour. The yellow markings on the abdomen and the bright yellow head were the most striking and peculiar features of this butterfly. He then circulated the photographs on ButterflyIndia@yahoogroups.com; an e-group for butterfly watchers around the world. It was finally identified and confirmed as the Yellow crested Spangle by Krushnamegh Kunte, post-doctoral research fellow at FAS centre for systems Biology, Harvard University.
‘‘The Yellow Crested Spangle belongs to the Genus Papilio under the family Papilionidae. Papilio elephenor is a highly endangered, federally protected species listed under Schedule I of the Indian Wildlife (Protection) Act, 1972, and is placed under the Endangered (EN A1c, B1 bc) category of the Red Data t of IUCN (Gupta et al, 2005),’’ epidopterologist said.
The butterfly is also endemic to the eastern Himalayas and northeastern India. Butterfly experts like Bingham (1907), Evans (1932) and Winter-Blyth (1957) have described the presence of this butterfly in Assam and Nagaland and Khasi Hills about 100 years ago, but there has been no recent report of its sightings or documentation till now.
Choudhury has also discovered another butterfly, called Moores cupid (Shijimia moorei Leech, 1889, old name Everes moorei). It is a tiny butterfly and its flight is very fast compared to its size. Choudhury said, ‘‘It is also an extremely rare butterfly under the Lycaenidae family. It is mainly found in Japan and southern China. Several decades earlier, its presence was reported from Meghalaya’s Khasi hills after which, it was not reported from anywhere else in India. This species is also listed in Schedule I of the Wildlife (Protection) Act, 1972 and categorized as Critically Endangered (CR A1c, B1 2bc) in the IUCN Red Data list’’.
Source : TimesOfIndia
Deep within the graveyard of butterflies, there moves a flutter of hope. And the awestruck nature-lover, bewildered at the miraculous triumph, captures a quick moment of the blithe spirits flight for posterity.
Kushal Choudhury, a young lepidopterologist and lecturer Kokrajhar Science College, has spotted a rare breed of swallowtail butterfly considered extinct at Ultapani Reserve Forest. The jungle, under Haltugaon forest division, is notorious for being the deathbed of hundreds these winged creatures.
Choudhury, who has been ing on a butterfly project since 2002
and is researching on swallowtail butterflies for his PhD since 2008, said, ‘‘The Yellow Crested Spangle (Papilio Elephenor Doubleday) was resighted after a long gap of 100 years in Ripu-Chirang Wildlife Sanctuary (RCWS) that extends between 89:554-90:304E and 27:154-26:354N in the Bodoland Territorial Council of western Assam.’’
He added, ‘‘The sanctuary is a transitional zone between Manas Tiger Reserve in the east and Buxa Tiger Reserve (West Bengal) in the west. It also has strong linkages with Bhutan Biological Conservation Complex as it is located just at the foothills of Phipsu Wildlife Sanctuary and Royal Manas National Park of Bhutan.’’
At first, Choudhury believed that it was a mutated spangle butterfly (Papilio protenor) that is similar in size and colour. The yellow markings on the abdomen and the bright yellow head were the most striking and peculiar features of this butterfly. He then circulated the photographs on ButterflyIndia@yahoogroups.com; an e-group for butterfly watchers around the world. It was finally identified and confirmed as the Yellow crested Spangle by Krushnamegh Kunte, post-doctoral research fellow at FAS centre for systems Biology, Harvard University.
‘‘The Yellow Crested Spangle belongs to the Genus Papilio under the family Papilionidae. Papilio elephenor is a highly endangered, federally protected species listed under Schedule I of the Indian Wildlife (Protection) Act, 1972, and is placed under the Endangered (EN A1c, B1 bc) category of the Red Data t of IUCN (Gupta et al, 2005),’’ epidopterologist said.
The butterfly is also endemic to the eastern Himalayas and northeastern India. Butterfly experts like Bingham (1907), Evans (1932) and Winter-Blyth (1957) have described the presence of this butterfly in Assam and Nagaland and Khasi Hills about 100 years ago, but there has been no recent report of its sightings or documentation till now.
Choudhury has also discovered another butterfly, called Moores cupid (Shijimia moorei Leech, 1889, old name Everes moorei). It is a tiny butterfly and its flight is very fast compared to its size. Choudhury said, ‘‘It is also an extremely rare butterfly under the Lycaenidae family. It is mainly found in Japan and southern China. Several decades earlier, its presence was reported from Meghalaya’s Khasi hills after which, it was not reported from anywhere else in India. This species is also listed in Schedule I of the Wildlife (Protection) Act, 1972 and categorized as Critically Endangered (CR A1c, B1 2bc) in the IUCN Red Data list’’.
Source : TimesOfIndia
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