A geoglyph of Titicaca - As seen by Google Maps
Thursday, March 3, 2011
Wednesday, March 2, 2011
Horse and dog - Tang Dinasty - China
An animal sits on a pad behind the saddle.
Hunters can have a dog or a cheetah with them.
China
Museo Arte Orientale, Torino
Tiny antennas for radio telescopes
"Tiny antennas form vast radio telescope array.
A grassroots telescope array is taking aim at a wide range of astronomy questions, with projects in geophysics and agriculture piggybacking on its infrastructure.
Dipole antennas dotting the Netherlands and several nearby countries together form a radio telescope that is sensitive in the relatively unexplored wavelength range of 1–10 m (roughly 10–250 MHz) and has an enormous field of view. About three-fourths of the telescope’s 44 stations are functioning, and the rest are set to be completed by the end of the year."
Dipole antennas dotting the Netherlands and several nearby countries together form a radio telescope that is sensitive in the relatively unexplored wavelength range of 1–10 m (roughly 10–250 MHz) and has an enormous field of view. About three-fourths of the telescope’s 44 stations are functioning, and the rest are set to be completed by the end of the year."
by Toni Feder, Physics Today March 2011
Tiny antennas form vast radio telescope array - Physics Today March 2011
It is the International LOFAR Telescope
http://www.lofar.org/about-lofar/image-gallery/latest-lofar-images
It is a radio interferometric array, consisting of many low-cost antennas. There are two distinct antenna types: the Low Band Antenna (LBA) between 10 and 90 MHz and the High Band Antenna (HBA) between 110 and 250 MHz. These "sensors" are organised many stations, distributed over an area about one hundred kilometres in diameter, located in the North-East of the Netherlands. This infrastructure will give rise to new resources for non-radio astronomers. In the geosciences field, it should be possible, for example, to extend the understanding of natural and induced seismicity, subsidence, and water management. The agricultural application of LOFAR is in the measurement of the micro-climate.
Tiny antennas form vast radio telescope array - Physics Today March 2011
It is the International LOFAR Telescope
http://www.lofar.org/about-lofar/image-gallery/latest-lofar-images
It is a radio interferometric array, consisting of many low-cost antennas. There are two distinct antenna types: the Low Band Antenna (LBA) between 10 and 90 MHz and the High Band Antenna (HBA) between 110 and 250 MHz. These "sensors" are organised many stations, distributed over an area about one hundred kilometres in diameter, located in the North-East of the Netherlands. This infrastructure will give rise to new resources for non-radio astronomers. In the geosciences field, it should be possible, for example, to extend the understanding of natural and induced seismicity, subsidence, and water management. The agricultural application of LOFAR is in the measurement of the micro-climate.
Acoustics of free-reed instruments
Documents dating back to before 1000 BC describe a wind instrument whose reed vibrates back and forth across the frame that houses it. Nowadays, free-reed instruments inspire both scholarly study and musical innovation. James Cottingham , Acoustic of free-reed instruments, Physics Today, March 2011, Vol.63, pp. 44-48.
A free reed? What is it? More http://www.patmissin.com/history/whatis.html
A free reed? What is it? More http://www.patmissin.com/history/whatis.html
Tuesday, March 1, 2011
Nazca
"The Nasca culture was the archaeological culture that flourished from 100 to 800 AD beside the dry southern coast of Peru in the river valleys of the Rio Grande de Nazca drainage and the Ica Valley (Silverman and Proulx, 2002). Having been heavily influenced by the preceding Paracas culture, which was known for extremely complex textiles, the Nasca produced an array of beautiful crafts and technologies such as ceramics, textiles, and geoglyphs (most commonly known as the Nazca lines)."
More Wiki
Cahuachi - pyramids
"Hablar de Cahuachi es hablar de una ciudad perdida en la noche de los tiempos. Cahuachi fue la capital teocrática de la Cultura Nasca gobernada por sacerdotes". More http://www.peruecologico.com.pe/esp_cahuachinasca_1.htm
Cahuachi was the major ceremonial center of the Nazca culture from 1 CE to about 500 CE. The "ciudad perdida" contains over 40 mounds topped with adobe structures. The permanent population was quite small. The town was apparently a pilgrimage center that grew its population during the ceremonial events. These events probably involved the Nazca lines.
"Cahuachi's most famous monument is the Great Pyramid, which hogs the skyline and casts an eye over the Nazca Lines, the geoglyphs which have made the culture so famous. As with most buildings in the city, the pyramid looks like a giant maze thanks to the winding ceremonial staircases which lead to its summit.... Many ceramics and other ceremonial items, such as fabrics and paintings, have been found in Cahuachi. ... Like many pre-Columbian American cities, Cahuachi was mysteriously abandoned, around 500 AD."
Cahuachi was the major ceremonial center of the Nazca culture from 1 CE to about 500 CE. The "ciudad perdida" contains over 40 mounds topped with adobe structures. The permanent population was quite small. The town was apparently a pilgrimage center that grew its population during the ceremonial events. These events probably involved the Nazca lines.
"Cahuachi's most famous monument is the Great Pyramid, which hogs the skyline and casts an eye over the Nazca Lines, the geoglyphs which have made the culture so famous. As with most buildings in the city, the pyramid looks like a giant maze thanks to the winding ceremonial staircases which lead to its summit.... Many ceramics and other ceremonial items, such as fabrics and paintings, have been found in Cahuachi. ... Like many pre-Columbian American cities, Cahuachi was mysteriously abandoned, around 500 AD."
Thanks to Wikipedia and Ed88!
Flying on Andes
"Birds were precious resources in the economy of Andean societies. Merchants traded brilliantly colored parrot and macaw feathers in long-distance networks connecting the Amazonian rainforest, the Cordillera, and the remote Pacific coast, where they adorned the sumptuous garments of rulers and kings. Coastal agriculturalists used guano to enrich their fields. Sailors collected the valuable fertilizer offshore on sacred islands, where they left prestigious offerings. On the coast, domesticated muscovy ducks may have been part of the subsistence."
Birds of the Andes, by Hélène Bernier, Source: Birds of the Andes | Thematic Essay | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art
Birds of the Andes, by Hélène Bernier, Source: Birds of the Andes | Thematic Essay | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art
Amazon Earthworks
Ancient Amazon Earthworks Seen by Satellite
"Amazonia is not the “wilderness” many assume it to be. For thousands of years human beings have been residing in and cultivating lowland and upland areas across the Amazon basin and beyond.
A recent article in National Geographic News provides a glimpse of earthworks built long before Columbus. Rediscoveries of the ancient croplands and city sites force us to re-evaluate notions of wilderness and to consider the long-standing, organized, cultural interactions and influences of humanity upon western landscapes."
"Amazonia is not the “wilderness” many assume it to be. For thousands of years human beings have been residing in and cultivating lowland and upland areas across the Amazon basin and beyond.
A recent article in National Geographic News provides a glimpse of earthworks built long before Columbus. Rediscoveries of the ancient croplands and city sites force us to re-evaluate notions of wilderness and to consider the long-standing, organized, cultural interactions and influences of humanity upon western landscapes."
http://news.nationalgeographic.com/news/2010/01/100104-amazon-lost-civilization-circles.html
http://archaeologynewsnetwork.blogspot.com/2010/11/amazonian-geoglyphs.html
http://archaeologynewsnetwork.blogspot.com/2010/11/amazonian-geoglyphs.html
Hidden simplicity
Hidden simplicity
"Casey and Anderson’s idea is based on the ansatz that the strange metal phase of the cuprates is described by an ordinary, well-understood Fermi-liquid theory that exists, but which is hidden in an unphysical Hilbert space (an analog of a Platonic world). In this picture, projecting the familiar Fermi liquid back into the physical world (i.e., making a measurement) converts the Fermi liquid into the experimentally observed strangeness. If Casey and Anderson’s theory withstands further experimental scrutiny, it will surely be a leap forward in our understanding of the cuprates. "– Alex Klironomos, Hidden simplicity
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.106.097002
Phys. Rev. Lett. 106, 097002 (2011)
Hidden Fermi Liquid: Self-Consistent Theory for the Normal State of High-TcSuperconductors
Philip A. Casey and Philip W. Anderson
Hidden Fermi liquid theory explicitly accounts for the effects of Gutzwiller projection in the t-J Hamiltonian, widely believed to contain the essential physics of the high-Tcsuperconductors. We derive expressions for the entire “strange metal,” normal state relating angle-resolved photoemission, resistivity, Hall angle, and by generalizing the formalism to include the Fermi surface topology—angle-dependent magnetoresistance. We show this theory to be the first self-consistent description for the normal state of the cuprates based on transparent, fundamental assumptions. Our well-defined formalism also serves as a guide for further experimental confirmation.
Phys. Rev. Lett. 106, 097002 (2011)
Hidden Fermi Liquid: Self-Consistent Theory for the Normal State of High-TcSuperconductors
Philip A. Casey and Philip W. Anderson
Hidden Fermi liquid theory explicitly accounts for the effects of Gutzwiller projection in the t-J Hamiltonian, widely believed to contain the essential physics of the high-Tcsuperconductors. We derive expressions for the entire “strange metal,” normal state relating angle-resolved photoemission, resistivity, Hall angle, and by generalizing the formalism to include the Fermi surface topology—angle-dependent magnetoresistance. We show this theory to be the first self-consistent description for the normal state of the cuprates based on transparent, fundamental assumptions. Our well-defined formalism also serves as a guide for further experimental confirmation.
One-way sound
One-way sound
" Xue-Feng Li and colleagues at Nanjing University and California Institute of Technology report on a new acoustic diode design that manipulates the sonic crystal itself to achieve nonreciprocal propagation of sound. The device consists of a two-dimensional sonic crystal arranged in a mesh of square steel rods. By rotating the steel rods, Li et al.are able to manipulate the unit cell of the sonic crystal element to turn the diode on (sound waves only propagate one way) and off (sound waves can move back and forth). Li et al. make their device entirely from linear acoustic materials, which allows them to control sound propagation with a simpler and more efficient process". – Daniel Ucko, One-way sound
Monday, February 28, 2011
Era de Pando, Peru
"Ancient Village in Liberec Department, Peru. This is a late Archaic site, thought to be created by the same Supe Culture responsible for the larger nearby site, Caral. The site includes and adobe pyramid and about two dozen buildings. A comparison aerial view on Google maps of both Caral and Era de Pando shows the similarities in architectural layout."
More http://www.megalithic.co.uk/article.php?sid=25983
More http://www.megalithic.co.uk/article.php?sid=25983
Caral, in Peru, the oldest town in the New World
"In 2001, the oldest town in South America was officially announced. Dating to 2600 BC, it pushed back the date for the “first town” with one millennium. What is even more intriguing, is that the town of Caral has pyramids, contemporary with the Egyptian Pyramid Era....The ancient pyramids of Caral predate the Inca civilization by 4000 years, but were flourishing a century before the pyramids of Gizeh. No surprise therefore that they have been identified as the most important archaeological discovery since the discovery of Machu Picchu in 1911" by Philip Coppens, read more http://www.philipcoppens.com/caral.html
Friday, February 25, 2011
Domenico Pacini and the discovery of cosmic rays
Domenico Pacini, uncredited pioneer of the discovery of cosmic rays
A. De Angelis
Vol 33 No 12 2010,
A. De Angelis
Vol 33 No 12 2010,
Rivista del Nuovo Cimento
Volume 033 Issue 12 pp 713-756
Published online: Fri, 28 Jan 2011
3D screen with voxels
"Researchers at Southampton University are using the holographic-style display to design a flawless-quality communication system that comes closer to the impression that users are in the same room.
... This ‘HoloVizio’ screen is made up of tiny elements called voxels (rather than pixels) that can represent depth information. Each voxel emits multiple beams of light that vary in colour and intensity depending on which direction they travel."
... This ‘HoloVizio’ screen is made up of tiny elements called voxels (rather than pixels) that can represent depth information. Each voxel emits multiple beams of light that vary in colour and intensity depending on which direction they travel."
Bent-Core Liquid Crystals
Most Cited Articles 2009 Japanese Journal Applied Physics
The 10 articles published in JJAP from 2006 to 2008 that were most frequently cited in 2009, in order of publication date. PDF files of the full text of these articles are available free of charge for one year from January 2011.
Bent-Core Liquid Crystals: Their Mysterious and Attractive World, by Hideo Takezoe, and Yoichi Takanishi, Jpn. J. Appl. Phys. 45 (2006) 597 [Abstract] [Full Text PDF Free ]
Bent-Core Liquid Crystals: Their Mysterious and Attractive World
Hideo TAKEZOE and Yoichi TAKANISHI
Structures and properties of liquid crystalline phases formed by bent-core molecules are reviewed. At least eight phases designated as B1–B8 have been found, being unambiguously distinguished from phases formed by usual calamitic molecules due to a number of remarkable peculiarities. In addition to B1–B8 phases, smectic A-like phases and biaxial nematic phases formed by bent-core molecules are also reviewed. The most attractive aspects of this new class of liquid crystals are in polarity and chirality, despite being formed from achiral molecules. The bent-core mesogens are the first ferroelectric and antiferroelectric liquid crystals realized without introducing chirality. Spontaneous chiral deracemization at microscopic and macroscopic levels occurs and is controllable. Moreover, achiral bent-core molecules enhance system chirality. The interplay between polarity and chirality provides chiral nonlinear optic effects. Further interesting phenomena related to polarity and chirality are also reviewed. [DOI: 10.1143/JJAP.45.597]
KEYWORDS: bent-core liquid crystals, polarity, chirality, ferroelectricity, antiferroelectricity, phase structure, layer structure, X-ray diffraction, nonlinear optics, SHG
Bent-Core Liquid Crystals: Their Mysterious and Attractive World
Hideo TAKEZOE and Yoichi TAKANISHI
Structures and properties of liquid crystalline phases formed by bent-core molecules are reviewed. At least eight phases designated as B1–B8 have been found, being unambiguously distinguished from phases formed by usual calamitic molecules due to a number of remarkable peculiarities. In addition to B1–B8 phases, smectic A-like phases and biaxial nematic phases formed by bent-core molecules are also reviewed. The most attractive aspects of this new class of liquid crystals are in polarity and chirality, despite being formed from achiral molecules. The bent-core mesogens are the first ferroelectric and antiferroelectric liquid crystals realized without introducing chirality. Spontaneous chiral deracemization at microscopic and macroscopic levels occurs and is controllable. Moreover, achiral bent-core molecules enhance system chirality. The interplay between polarity and chirality provides chiral nonlinear optic effects. Further interesting phenomena related to polarity and chirality are also reviewed. [DOI: 10.1143/JJAP.45.597]
KEYWORDS: bent-core liquid crystals, polarity, chirality, ferroelectricity, antiferroelectricity, phase structure, layer structure, X-ray diffraction, nonlinear optics, SHG
Thursday, February 24, 2011
La Medusa di Wayland's Smithy
Un crop circle del 2009, che si vede con Google Maps. "Formazione anomala, e spettacolare. È stata riportata da tutti i media internazionali in quanto dotata di una rara quanto unica energia espressiva."
Wayland's Smithy is a Neolithic long barrow and chamber tomb site located near the Uffington White Horse and Uffington Castle, at Ashburyin the English county of Oxfordshire (historically in Berkshire).
Wayland's Smithy is a Neolithic long barrow and chamber tomb site located near the Uffington White Horse and Uffington Castle, at Ashburyin the English county of Oxfordshire (historically in Berkshire).
Shale gas
From Wiki "Shale gas is natural gas produced from shale. Shale gas has become an increasingly important source of natural gas in the United States over the past decade, and interest has spread to potential gas shales in Canada, Europe, Asia, and Australia. One analyst expects shale gas to supply as much as half the natural gas production in North America by 2020."
Study says natural gas use likeky to double, NYTimes, http://www.nytimes.com/2010/06/25/business/energy-environment/25natgas.html?_r=1&src=busln
Study says natural gas use likeky to double, NYTimes, http://www.nytimes.com/2010/06/25/business/energy-environment/25natgas.html?_r=1&src=busln
Dal Sole24ore "L'Eia ha ritoccato le stime sulle riserve nazionali di shale gas - il metano che si ricava da antiche e stratificate formazioni rocciose – più che raddoppiandole. Così, quegli Stati Uniti già abbastanza ossessionati dalla dipendenza dal petrolio d'importazione, scoprono con sollievo di essere una potenza nel gas: secondo l'Eia, nel 2035 il 45% del fabbisogno americano verrà dalle rocce sedimentarie."
Wednesday, February 23, 2011
American mastodon
Mastodons were large tusked mammal species of the extinct genus Mammut which inhabited Asia, Africa, Europe, North America and Central America from the Oligocene through Pleistocene, 33.9 mya to 11,000 years ago. The American mastodon is the most recent and best known species of the group.
The American mastodon, Mammut americanum, lived from about 3.7 million years ago until about 10,000 BC. It was the last surviving member of the mastodon family. It is known from fossils found ranging from present-day Alaska and New England in the north, to Florida, southern California, and as far south as Honduras and El Salvador.
http://en.wikipedia.org/wiki/Mastodon
The American mastodon, Mammut americanum, lived from about 3.7 million years ago until about 10,000 BC. It was the last surviving member of the mastodon family. It is known from fossils found ranging from present-day Alaska and New England in the north, to Florida, southern California, and as far south as Honduras and El Salvador.
http://en.wikipedia.org/wiki/Mastodon
Cryogenic energy storage
Cryogenic energy storage plant could provide valuable back-up | News | The Engineer
"The UK’s first cryogenic power storage plant, which uses liquid nitrogen to store and release energy, is scheduled to open next month. Its operator, Highview Power Storage, said the system could provide a relatively cheap way of storing power, particularly from intermittent sources such as wind turbines, to better match the supply of electricity to demand.The pilot facility near Slough has been providing electricity to the National Grid since April last year by evaporating liquid nitrogen stored at -200ºC to drive turbine generators. Highview is now installing equipment to re-liquefy and compress the nitrogen using electricity from the grid, creating a closed cryogenic system that can store energy at times of surplus and release it when it is needed, while re-using the cold air exhaust."
"The UK’s first cryogenic power storage plant, which uses liquid nitrogen to store and release energy, is scheduled to open next month. Its operator, Highview Power Storage, said the system could provide a relatively cheap way of storing power, particularly from intermittent sources such as wind turbines, to better match the supply of electricity to demand.The pilot facility near Slough has been providing electricity to the National Grid since April last year by evaporating liquid nitrogen stored at -200ºC to drive turbine generators. Highview is now installing equipment to re-liquefy and compress the nitrogen using electricity from the grid, creating a closed cryogenic system that can store energy at times of surplus and release it when it is needed, while re-using the cold air exhaust."
Lanzan pájaro espía
Un miniavión espía en forma de colibrí que funciona a control remoto fue presentado por el Pentágono.
Tuesday, February 22, 2011
Dancing galaxies
Il Sole24ore propone una collezione di immagini con la danza delle galassie. Vedi
http://foto.ilsole24ore.com/SoleOnLine5/Tecnologie/Scienza/2011/danza-galassie/danza-galassie_fotogallery.php?id=2
http://foto.ilsole24ore.com/SoleOnLine5/Tecnologie/Scienza/2011/danza-galassie/danza-galassie_fotogallery.php?id=2
A stellar superfluid
Physics - A stellar superfluid, is the Nicolas Chamel's viewpoint on the paper:
Rapid Cooling of the Neutron Star in Cassiopeia A Triggered by Neutron Superfluidity in Dense Matter
Dany Page, Madappa Prakash, James M. Lattimer, and Andrew W. Steiner
Phys. Rev. Lett. 106, 081101 (2011) – Published February 22, 2011
Download PDF (free)
Friday, February 18, 2011
Physicists create 'anti-laser'
Physicists create 'anti-laser' - physicsworld.com
"In a fascinating case of physics being turned on its head, a group of researchers at Yale University in the US has created an "anti-laser" that almost perfectly absorbs incoming beams of coherent light. The invention is based on a theoretical study reported last summer in which Douglas Stone and his Yale colleagues claimed that such a system could be possible in a device that they call a coherent perfect absorber (CPA). Instead of generating coherent light beams with a laser, the devices absorb incoming coherent light and convert it into either heat or electricity."
DNA puts a new spin on electrons
DNA puts a new spin on electrons - physicsworld.com
"A new and highly efficient way of filtering electrons according to their spin has been built using double strands of DNA. The technique, which has been developed by physicists in Israel and Germany, is about three times more efficient than using magnet-based spin filters. The method could be used in spintronic circuits, which exploit both the spin and charge of electrons, and could even lead to a better understanding of the possible role that spin plays in biological processes."
"A new and highly efficient way of filtering electrons according to their spin has been built using double strands of DNA. The technique, which has been developed by physicists in Israel and Germany, is about three times more efficient than using magnet-based spin filters. The method could be used in spintronic circuits, which exploit both the spin and charge of electrons, and could even lead to a better understanding of the possible role that spin plays in biological processes."
Wednesday, February 9, 2011
The Sun in 3D
"Beginning on February 6, 2011, the two STEREO spacecraft are 180 degrees apart providing Naval Research Laboratory scientists with a 360-degree view of the Sun. NASA's STEREO (Solar Terrestrial Relations Observatory) spacecraft were launched on October 25, 2006, and have been gathering spectacular images of solar activity, especially solar storms, since the mission began."
More http://www.nrl.navy.mil/pao/pressRelease.php?Y=2011&R=22-11r and http://stereo.gsfc.nasa.gov/360blog/
A 3D movie at the page:
http://www.nasa.gov/mission_pages/stereo/multimedia/AnaglyphFull171Movie.html
http://www.nasa.gov/mission_pages/stereo/multimedia/AnaglyphFull171Movie.html
Sunday, February 6, 2011
Two splendid suns
"Earth could be getting a second sun, at least temporarily. Dr. Brad Carter, Senior Lecturer of Physics at the University of Southern Queensland, outlined the scenario to news.com.au. Betelgeuse, one of the night sky's brightest stars, is losing mass, indicating it is collapsing. It could run out of fuel and go super-nova at any time.
When that happens, for at least a few weeks, we'd see a second sun, Carter says. There may also be no night during that timeframe."
When that happens, for at least a few weeks, we'd see a second sun, Carter says. There may also be no night during that timeframe."
More The Huffington Post
Friday, February 4, 2011
North Atlantic strait at its warmest for 2000 years
"A stretch of water east of Greenland, considered to be the Arctic's main source of heat from the North Atlantic, is warmer now than it has been in at least 2000 years. That is the claim of researchers in Europe and the US who suggest further warming will amplify the effects of climate change in the Arctic region."
North Atlantic strait at its warmest for 2000 years - physicsworld.com
North Atlantic strait at its warmest for 2000 years - physicsworld.com
Thursday, February 3, 2011
Fotovoltaico organico
Come celle solari organiche si intendono quei dispositivi la cui parte fotoattiva è basata sui composti organici del carbonio, includendo anche quelle celle più prettamente di tipo ibrido. La struttura base di una cella organica è un "sandwich" composto da un substrato e da una o più sottilissime pellicole contenenti i materiali fotoattivi, in mezzo a due elettrodi conduttivi di cui uno trasparente.
"La gamma di celle solari organiche è ampia e si trova in diversi stadi di ricerca e di maturazione tecnologica e comprende, in sintesi, le celle “dye sensitized” (o DSSC), le celle totalmente organiche (anche dette plastiche), e le celle ibride organico/inorganico. Per le celle DSSC (o di Grätzel, dal nome del loro inventore), la parte fotoelettricamente attiva, spessa qualche micrometro ed inserita tra due elettrodi, è costituita da un pigmento organico, da ossido di titanio e da un elettrolita. Le celle DSSC, ispirandosi al processo di fotosintesi clorofilliana, utilizzano una miscela di materiali in cui un pigmento assorbe la radiazione solare e gli altri componenti estraggono la carica per produrre elettricità. Infatti è possibile ottenere l’effetto fotovoltaico anche con pigmenti vegetali. Efficienze massime del 10-11% e tempi di vita di vari anni, valori comunque in costante aumento, sono stati misurati in laboratorio per questo tipo di cella singola, utilizzando pigmenti sintetizzati attraverso i processi della chimica organica. ...
Le celle fotovoltaiche completamente organiche, sia quelle a “small molecules”, realizzate attraverso un’evaporazione sotto vuoto, sia quelle polimeriche, realizzate attraverso deposizione in forma liquida, sono recentemente arrivate al 4-5% di efficienza massima per celle in laboratorio. Queste celle, anche conosciute come “plastiche”, sono molto interessanti in quanto le tecniche di fabbricazione sono le più semplici da attuare."
More Rinnovabili.it: L’evoluzione “organica” delle celle fotovoltaiche
"La gamma di celle solari organiche è ampia e si trova in diversi stadi di ricerca e di maturazione tecnologica e comprende, in sintesi, le celle “dye sensitized” (o DSSC), le celle totalmente organiche (anche dette plastiche), e le celle ibride organico/inorganico. Per le celle DSSC (o di Grätzel, dal nome del loro inventore), la parte fotoelettricamente attiva, spessa qualche micrometro ed inserita tra due elettrodi, è costituita da un pigmento organico, da ossido di titanio e da un elettrolita. Le celle DSSC, ispirandosi al processo di fotosintesi clorofilliana, utilizzano una miscela di materiali in cui un pigmento assorbe la radiazione solare e gli altri componenti estraggono la carica per produrre elettricità. Infatti è possibile ottenere l’effetto fotovoltaico anche con pigmenti vegetali. Efficienze massime del 10-11% e tempi di vita di vari anni, valori comunque in costante aumento, sono stati misurati in laboratorio per questo tipo di cella singola, utilizzando pigmenti sintetizzati attraverso i processi della chimica organica. ...
Le celle fotovoltaiche completamente organiche, sia quelle a “small molecules”, realizzate attraverso un’evaporazione sotto vuoto, sia quelle polimeriche, realizzate attraverso deposizione in forma liquida, sono recentemente arrivate al 4-5% di efficienza massima per celle in laboratorio. Queste celle, anche conosciute come “plastiche”, sono molto interessanti in quanto le tecniche di fabbricazione sono le più semplici da attuare."
More Rinnovabili.it: L’evoluzione “organica” delle celle fotovoltaiche
Drilling for geothermal energy
"An exploration team in Newcastle plan to drill through old mining tunnels to search for geothermal energy under the city centre. Researchers from Newcastle University who are leading the project hope it could initially provide up to 5MW of thermal energy, with potentially more heat and electricity from future boreholes. This would provide heat for a new campus that will combine research facilities with affordable housing, while some energy may be siphoned off the power a nearby shopping centre."
Read more Drilling to begin on Newcastle geothermal energy scheme | News | The Engineer
Read more Drilling to begin on Newcastle geothermal energy scheme | News | The Engineer
Polarization of light
At the HyperPhysics site you can find a classification of the polarization of light.
http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polclas.html
http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polclas.html
The 3D light for spintronics
"Circularly polarized light, which is used in 3D movies, has its electric field vector rotating like a clock hand. It's typically produced by sending light through a filter, but now a team has created a small, solid device that emits partially circularly polarized light, as they describe in the 4 February Physical Review Letters. If this semiconductor technology can be further perfected, it could be used in devices that help biochemists control protein synthesis or help physicists control electrons in spintronics--a futuristic type of electronics." More in "Giving Light a Spin", Physical Review Focus
Nanobeads with liquid hydrogen to fuel cars?
"Plastic nanobeads that can store hydrogen at room temperature as a liquid are being commercialised for fuel applications by technology start-up Cella Energy." This is announced in an article by Andrew Czyzewski, The Engineer. More Nanobeads could store liquid hydrogen to fuel cars | News | The Engineer
Atlantic Wind Connection
Su Google. "... il gigante di Mountain View lancia un progetto mastodontico di energia eolica per le famiglie americane. Si chiama Atlantic Wind Connection (Awc) ed un progetto che si pone l'obiettivo di portare energia pulita nelle case di almeno due milioni di famiglie americane della East Coast. Il progetto vede coinvolta Google e vale sulla carta circa cinque miliardi di dollari, cifra necessaria per erigere a circa 15 miglia dalla costa degli Stati Uniti bagnata dall'Oceano Atlantico una dorsale di turbine eoliche lunga 350 miglia, che partirebbe da New York per raggiungere in direzione Sud la Virginia in quel di Norfolk."
More sole24ore
More sole24ore
A star and six planets
"A newfound planetary system has six worlds, five of which rank among the smallest known, and the list of unconfirmed candidates has swelled to four figures.
Thirty million kilometers away, trailing the pale blue dot that is Earth as it orbits the sun, is a spacecraft designed to find some of the countless other pale blue dots that may speckle the galaxy. NASA launched this spacecraft, known as Kepler, in 2009 to take a census of Earth-like planets in the hopes of figuring out how common—or how rare—are the conditions under which life has thrived here."
more Scientific American
Una stella e sei pianeti
"Una stella molto simile al Sole ed intorno a lei 6 pianeti che ruotano, un vero e proprio Sistema solare. Ma non è certo il nostro, dato che sta a 2.000 anni luce dalla Terra, una distanza enorme su scala umana, ma molto piccola i termini astronomici. La stella si chiama Kepler 11 e la scoperta del sistema di sei pianeti, tutti piccoli e alcuni con caratteristiche di tipo terrestre, è riportata nella rivista Nature del 3 febbraio."