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Tizer
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17/01/2008
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12:31
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Russian fuel flows in Jules Verne's veins
European Space Agency press release (15 January 2008). A slight change from steam engines!Fuelling of the Jules Verne Automated Transfer Vehicle has started at Europe's Spaceport. ATV is being loaded with Russian refuelling propellant destined for the International Space Station. After a month of fuelling operations, the launch and maiden voyage of the first European resupply spaceship is scheduled for the second half of February.
Early this month, the 20-tonne Jules Verne Automated Transfer Vehicle (ATV) was transferred to the huge fuelling chamber within the giant S5 integration building at Europe's Spaceport in Kourou, French Guiana.
Inside the fuelling chamber, the spacecraft was prepared for preliminary propellant filling operations, which began as scheduled on 8 January and will continue until early February.
In cooperation with ESA's ATV project experts and Russian engineers on site, a dozen specialised technicians from Astrium sites in Bremen, Lampoldshausen (Germany), Stevenage (United Kingdom) and Les Mureaux (France) are in charge of these time-consuming and delicate operations.
"We are pleased with how well the schedule is progressing so far. This week, as planned, two identical tanks on the ATV were successfully loaded with 296 kg of Russian UDMH (Unsymmetric Dimethyl Hydrazine) which is the propellant fuel to be delivered to the International Space Station's (ISS) Russian-built propulsion tanks", said Dominique Siruguet, ESA ATV Campaign Manager.
Protective suits
As a precaution against the toxic and explosive characteristics of the hydrazine, a series of strict measures are in place, such as the requirement for the ‘scapemen' - the fuelling specialists - to wear special suits during fuelling operations. There are three teams of three ‘scapemen'. Because it is exhausting work wearing a pressurized suit in a high-risk environment, their task is limited to periods of four hour operations.
Next week, the oxidizer Nitrogen Tetroxide (N2O4) (which provides a source of oxygen so the fuel can ignite and burn in orbit), will also be stored on board the ATV to be delivered in orbit to the ISS. When Jules Verne is attached to the Station, both Russian produced UDMH and Nitrogen Tetroxide will be transferred through dedicated pipes which pass through the docking mechanism to the Space Station's own plumbing.
Fuel for ATV
On 20 January, 20 kg of pressurized gaseous oxygen will be loaded into Jules Verne. Through to the end of the month, the largest quantity of propellant will be fuelled on board: around 2216 kg of MMH (Monomethylhydrazine) and MON3 (Mixed Oxides of Nitrogen) propellant which will be used by the ATV's own propulsion system. It will be used for the ATV's autonomous navigation towards the ISS and, once docked, to control the attitude and orbit, including re-boost of the whole space complex. In free flight the ATV navigates as a fully automated spaceship, with four main engines (490 N thrust) plus 28 smaller thrusters (220 N) for attitude control.
Four propellants
"The month-long fuelling campaign is a result of having to load four different propellants, some in large quantities, and also some oxygen. Since each propellant is complex and dangerous to handle, the preparatory operations - the safety rules and the decontamination - takes much more time than the actual pressurized transfer of each product into the vehicle," underlines Nicolas Chamussy, Astrium ATV Programme Manager based at Astrium facilities in Les Mureaux (France) and in Bremen (Germany). Quantitatively the ATV propellant load is at least three times that of the largest commercial satellites.
By the time ATV is moved to the BAF (Batiment d'Assemblage Final) in the first week of February, where it will be mated to Ariane 5 launcher, the ATV will hold four different types of propellant and 20 kg of oxygen, giving a total propellant mass of about 6.5 tonnes.
The whole Jules Verne ATV is 19.4 tonnes, including approximately 1300 kg of ‘dry cargo'. During fuelling operations, the ATV is electrically completely shut down for safety reasons, but each day the whole spacecraft is activated to check the spacecraft's ‘health', and charge the batteries once again.
Launch vehicle
The go-ahead for the start of Jules Verne fuelling operations also prompted the Astrium teams in Kourou to initiate the active preparation and integration of the Ariane 5. ATV will be carried into orbit by a special version of the Ariane 5 launch vehicle called the Ariane 5 Evolution Storable upper stage Automated Transfer Vehicle, or A5 ES-ATV for short. The mating of the two large vehicles is scheduled for early February.
Edited by - Tizer on 17/01/2008 12:35:21
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Tizer
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Posted - 17/01/2008 : 12:34
New survey to reveal "Britain's Atlantis"
15 January 2008 press release from University of Southampton.
The lost city of Dunwich, Britain's own underwater 'Atlantis', which has captured the imagination of people for centuries, could be revealed for the first time with high-tech underwater sonar.
Professor David Sear, of the University of Southampton, and marine archaeologist Stuart Bacon, will explore the ancient sunken city, off the Suffolk coast, in the early summer.
Dunwich, fourteen miles south of Lowestoft, was once a thriving port, and in the 14th century similar in size to London. However, storms, erosion and floods over the past six centuries have almost wiped out this once prosperous city, and the Dunwich of today is a quiet coastal village.
The project will use the latest underwater acoustic imaging technology to assess the existence of any remains from the city that lies between 10ft (3m) and 50ft (15m) down.
Professor Sear comments: 'We will be applying new technology to the investigation of what has become known as "Britain's Atlantis", and making this information publicly available. Technical advances, such as side-scan multibeam sonar have massively improved our ability to create accurate acoustic images of the seafloor, and this survey should greatly enhance our knowledge of the site.'
Diving evidence suggests the site contains debris from at least two churches and a priory, but underwater visibility at the location is very poor, and no one has any idea what remains (if any) exist from the medieval settlement that was lost in the 13th and 14th centuries.
Stuart Bacon, Director of the Suffolk Underwater Studies, first located the lost city in the 1970s and has dived there many times. He and Professor Sear hope to begin exploring the seabed in June.
The city-scale survey of the sea floor will provide information on the location and state of any structures of archaeological interest in relation to historical records. The findings will be presented as a new public display for the Dunwich Museum, documenting the technology used and what the project has revealed of the lost city.
The expedition is being funded by a £20,000 donation from the Esmée Fairbairn Foundation. The GeoData Institute, a University of Southampton-based research and consultancy group, is managing the project and dealing with collation and digital capture of the data and interpretation, while EMU Ocean Survey are conducting the actual survey.
Edited by - Tizer on 17/01/2008 12:36:07
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Tizer
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Posted - 17/01/2008 : 12:38
Pigmentation in butterfly wings
16 January 2008 press release from University of Groningen, Netherlands.
Nowhere in nature is there so much beautiful colour as on the wings of butterflies. Scientists, however, are still baffled about exactly how these colours are created. Marco Giraldo has been examining the structure of the surface of the wings of the cabbage white and other butterflies. Among the things he has discovered is why European cabbage whites are rebuffed more often than Japanese ones. Giraldo will be awarded a PhD by the University of Groningen on 25 January 2008.
The colours on butterfly wings are used as an advertisement. The patterns on the wings enable butterflies to recognize their own species at a distance and differentiate between males and females – rather handy when you’re hunting for a partner. Just like a pointillist painting, the surface of the wing is constructed of a huge collection of coloured dots, called scales, each about 50 x 250 micrometers in size. However, scientists don’t yet know very much about how the colour on the wings is formed. What they do know is that the colours are created in two different ways: via pigments and via nanostructures on the scales, which ensure that light is distributed in ways that are sometimes spectacular. These so-called structure colours can clearly be seen on the morpho butterflies of the South American rainforests.
Cabbage white
Marco Giraldo examined the structure and the pigments of the wings of the cabbage white and other Whites from the Pieridae family. The physicist chose the Whites because they have relatively simple pigmentation. By comparing the scales of various sorts under an electron microscope, he discovered how the colouration of Whites is caused. Giraldo is the first to clarify how the colour of these butterflies is influenced by the nanostructural characteristics.
Scale structure
Although the spatial structure of a scale depends on the type of butterfly, there are a number of general characteristics: A scale consists of two layers, linked by pillars. The undersurface is virtually smooth and without structure, but the upper surface is formed by a large number of elongated, parallel ridges, about one to two micrometers from each other. The colour is determined by the dispersal of light by the scale structures and by the absorption of light by any pigments present. The pigments of the cabbage white, for example, absorb ultraviolet light and the brimstone blue light. At the same time they also scatter white or yellow light respectively.
Effective
Giraldo also discovered that the wings of Whites are constructed in a surprisingly effective way. Both sides of the wings have two layers of overlapping scales that reflect light. The more scales there are, the more light is reflected. This light reflection is very important as butterflies want to be seen. Giraldo discovered that these two layers form an optimal construction: with more than two layers the reflection may be improved, but the wing would become disproportionately heavy.
Japanese males
Giraldo has also discovered why Japanese male cabbage whites are better at recognizing females than European cabbage whites, who still make mistakes in this area. This is because the wings of Japanese male and female cabbage whites differ subtly, unlike those of their European relatives: the scales on the wings of Japanese female cabbage whites lack specific pigment grains, those that ensure that UV light is absorbed. Males do have these pigment grains, as do both sexes of the European cabbage whites. This difference makes it easier for Japanese male cabbage whites, who unlike humans can see UV light, to differentiate between males and females.
Colour industry
New colour methods can be developed using the knowledge derived from Giraldo’s research. It may be possible to apply the nanostructures observed in butterflies to create impressive optic effects in paint, varnish, cosmetics, packaging materials and clothes. Industry is thus following butterfly wing research with great interest.
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Doreen
hippies understudy
429 Posts
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Posted - 17/01/2008 : 17:08
Very interesting, coulor is so important, can you imagine our world without it?
Dordygail 
always the one to make the best of things. |
Tizer
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Posted - 17/01/2008 : 20:25
As you say Doreen, colour is so important to us. Yet visible light is only a tiny part of the electromagnetic spectrum. If we could see infra-red and ultra-violet as well it would be an even more amazing world!
And when light bounces off a relective surface such as water some of it gets polarised - this type of light is what polaroid lenses filter out. But some animals - frogs, for instance - can detect polarised light and that makes it easy for them to find a pond. So that's why you don't see frogs wearing polaroid sunglasses!
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Ribble Rouser
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Posted - 22/01/2008 : 07:55
Thanks Tizer. Very interesting articles. Space travel, archaeology and lepidoptery, all in the space of a few minutes. Great! More?
it's bums that count 'ere; not 'ats |
Tizer
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Posted - 22/01/2008 : 10:57
Well RR, you did ask!
Nuclear and coal in the UK energy mix
University press release (21 January 2008)
Renewable energy must be developed in parallel with nuclear power and a clean-up of coal-fired power station technology, if the UK is to meet increasing demand without relying on enormous and potentially debilitating natural gas imports. That is the conclusion drawn from a report to be published in Inderscience's International Journal of Nuclear Governance, Economy and Ecology.
Muhammad Asif of the School of Built and Natural Environment, Glasgow Caledonian University, Glasgow and colleagues John Currie and T. Muneer at the School of Engineering and Built Environment, Napier University, Edinburgh, explain that the provision of sufficient, affordable and secure energy is crucial for any modern economy.
However, across the globe, those same economies are facing challenges such as climate change, limited resources and rising costs. The team has analysed the situation facing the UK and offers a solution based on energy security and diversity in the supply mix that could be the most sustainable option for the country.
Asif and his colleagues explain how currently the UK is self sufficient in natural gas, exporting approximately the same quantities as it imports. The major energy contributors are coal, oil, gas and nuclear power. This is set to change quickly, however, the UK's oil and gas reserves dwindle and coal and nuclear power stations, which today produce almost 54% of the UK total electricity needs will reach the end of their working life.
"It is estimated that the 'business as usual' scenario, over the next two decades, could result in the loss of almost one third of the UK's electricity production capacity," the researchers say. That equates to a loss of 25 Gigawatts of electricity production by the year 2023. The UK will soon have to face the challenge of bridging the widening gap between energy supply and demand.
Others have suggested that the energy mix should shift more towards, gas-fired power stations. However, this could be devastating to the UK economy, Asif and colleagues emphasis. It would increase immensely our reliance on natural gas imports, as well as reducing diversity and so security in the energy mix.
Asif and his colleagues conclude from their energy analysis that the most secure approach to energy supply after 2023 will involve nuclear expansion, the development of clean coal-fired power stations and a dramatic increase in renewable energy sources.
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Tizer
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Posted - 22/01/2008 : 11:04
Copper's not coping: new chips call on light speed
European research press release, 18 January 2008The tiny copper wires that connect different areas of an integrated circuit may soon limit microchip-processing speeds. So European researchers have developed technologies to produce and combine semiconductor microlasers with silicon wave guides for novel, power-efficient optical connections.
We have all experienced the effect of Moore's Law: almost from the second you unpack a newly purchased computer it is already outdated. The next model - with faster processing power and more advanced features - is already in the shop.
Gordon E. Moore, co-founder of Intel, described the phenomenon of microchip miniaturisation in 1965 when he observed that the number of transistors you can fit into an integrated circuit appeared to double about every two years.
The microelectronics industry still follows this "law", but unless new fabrication or microprocessing technologies are quickly developed this relentless miniaturisation may peter out in less than a decade. Microchips based on silicon wafers are nearing their theoretical limits as physical properties of near nanoscale silicon integrated circuits begin to interfere with their performance.
The speed of data transfer within integrated circuits is one of the major bottlenecks. At present, to pass information from one part of a chip to another, the data packet is sent as electrons through copper wires, known as copper interconnects.
These wires may be just a few millimetres in length, but for the electrons it is like running between underground trains at rush hour. The electrons must all squeeze down narrow tunnels while a crowd backs up at the entrance.
Copper can't cope
"Copper-wire interconnects place serious limitations on the performance of silicon integrated circuits," says Dries Van Thourhout from Ghent University's Photonics Research Group and Belgium's micro- and nanoelectronics research centre IMEC. "It is hard to transmit data down these interconnects in a sufficiently fast, power-efficient way. It is a problem of bandwidth and copper will not be able to cope with the processing power of tomorrow's microchips."
Optical interconnects use light instead of electrons to represent information; they are a highly appealing alternative to copper interconnects, with the potential to be far more efficient, transmitting more data but using the same or even less power.
Instead of travelling along copper wires, photons travel the distance between source and detector along wave guides, like miniature optical fibres. At this scale, however, the wave guides are made out of silicon rather than glass.
"Lots of research has shown that you can etch wave guides for photons into silicon," says Van Thourhout. "This is great because you are using the same materials and fabrication technologies as you do to make integrated circuits. But there is one significant drawback: it is extremely hard to get light out of silicon."
Despite extensive research to exploit many of silicon's peculiar properties, it is highly unlikely that purely silicon-based lasers will reach an efficiency comparable to that of their semiconductor-based cousins for the foreseeable future.
Van Thourhout has coordinated a European consortium that has successfully combined the best of both worlds: silicon wave guides and microscale lasers made from a semiconductor call indium-phosphate. The PICMOS project was a partnership between several European research institutions, universities and two French companies STMicroelectronics and TRACIT Technologies, now owned by Soitec.
Mini-laser system
Part of the research involved the fabrication of a miniaturised laser system small enough to generate light for each interconnect. The PICMOS partners developed a method to etch indium-phosphate lasers with a diameter of just 7µm, sufficiently small to integrate several thousand onto a 2cm x 2cm silicon chip. This is the first time that such compact lasers have been produced in a very practical, cost-efficient way.
The tiny lasers could also have applications in miniature optical sensors, such as strain detectors, or be used to build incredibly cheap, but very powerful optical biosensors. But the biggest breakthrough in the project was the development of a bonding technology that joins the silicon and iridium-phosphate materials together.
"The bonding process, now transferred to TRACIT, effectively 'glues' the silicon and semiconducting indium-phosphate in layers. It is possible to etch out the microlasers and the silicon wave guides and produce an optical interconnecting layer," says Van Thourhout. "The bonding process and the refinement of the microlaser and the accompanying detectors have been major breakthroughs."
The production cost of the prototype optical interconnect layer is still too high for mass production, although the results from the demonstrator 'chip' have been extremely encouraging. A follow-up project, WADIMOS, will continue to drive the PICMOS platform towards commercialisation. In particular it will develop a pilot line that integrates the fabrication of the optical interconnect layer into the regular integrated circuit manufacturing process.
"We envisage a layer on an integrated circuit that sits on top of the classical etched copper electrical interconnect layer," says Van Thourhout. "This optical interconnect layer would be less sensitive to temperature, immune from electromagnetic noise, and have lower power consumption. Meanwhile, the bonding system could be adapted for many other electronics applications, for example to stack integrated circuits and in microfluidic technologies. The application of the PICMOS platform could be tremendous for tomorrow's chip technologies and wide-ranging in many other associated applications."
Web site:
http://cordis.europa.eu/ictresults/index.cfm/section/news/tpl/article/BrowsingType/Features/ID/89457
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Tizer
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Posted - 24/01/2008 : 15:52
France set for rapid growth in photovoltaic technology
Press release from the French Technology Press Bureau (24 January 2008).
Photovoltaic (PV) technology is set to become one of France’s fastest growing energy sources over the next decade, as dramatic increases in world oil prices radically shift the balance in favour of renewable energy sources.
France’s energy record is already very good – it has one of the lowest carbon footprints in Europe and is meeting its Kyoto Treaty obligations. France has seen energy consumption (calculated per unit of GDP) fall dramatically, with a reduction every year since 1982. It is already a world leader in other forms of renewable energy (producing 13% of its energy through renewables in 2004, notably through hydropower and biomass). PV growth has accelerated in the past year, as attractive tax rebates and other measures have taken effect. Further rapid growth in PV capacity in France is expected over the next decade.
While other European nations are nowadays discovering that they are too reliant on supplies of gas delivered from Russia and Central Asia, the French government has already set strategic targets for its overall energy policy. In the Energy Act of 2005, France established the following goals: to safeguard France’s energy independence and security of supply; to ensure competitive prices for industry and private consumers; and, finally, to fight against climate change and protect the environment.
The French government is promoting PV energy through feed-in tariffs – a rate paid to consumers for power fed back into the grid. At present this runs at €0.30/kWh in mainland France, with higher rates in Corsica and overseas départements (such as Martinique). Global trends in PV development favour small-scale, Building Integrated PV (BIPV) applications – and the government recognises this, by adding a premium for such schemes, reimbursing €0.55/kWh for BIPV generation.
Thanks to tax credits of up to 50% for PV production equipment, as well as the most attractive R&D tax credit climate in the whole of Europe, a number of new companies are expected to set up, or team up with French companies in order to develop the next generation of PV arrays.
One UK-based player that is already about to benefit from the predicted growth in PV sales is Europe's leading solar-energy company, Solarcentury, which specialises in building integrated solar-energy products. In March 2007, Solarcentury set up its French subsidiary in La Rochelle (in western France). According to Derry Newman, CEO, “The feed-in tariff in France is by far the most effective in Europe. With regional grants available in some areas on top of that, France is a very attractive market for us. Our building-integrated solar products are being specifically accredited for commercial and residential buildings in France, as we are determined that a wide variety of individuals and their buildings are given the very best opportunity to go solar.”
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