January 24, 2009

If the Terrorists Attack Our Ports It Probably Will Not Be A Nuclear Attack

A nightmare attack on our ports.

Many anti-nuclear power people repeat a few of mistakes frequently. There are other mistakes but this article will focus on the ones below. Here is a quote from the typically misguided ideas.

In May 2006, the House overwhelmingly approved by a 421 to 2 vote, legislation to provide $7.4 billion in spending on new port security inspectors, nuclear weapons screening and the development of an automated system to pinpoint high-risk cargo.

The economic impact of even a single nuclear terrorist attack on a major U.S. seaport would be very great. In the three plausible scenarios examined, a successful attack would create disruption of U.S. trade valued at $100-200 billion, property damage of $50-500 billion, and 50,000 to 1,000,000 lives could be lost. Global and long-term effects, including the economic impacts of the pervasive national and international responses to the nuclear attack, though not calculated, are believed to be substantially greater.

1. They make a big deal about potential cost and damage from various forms of nuclear enabled terrorist attack.

There are several wrong assumptions in that idea. One of the big ones is that there are not non-nuclear attacks that can be as damaging and deadly as a nuclear attack. The non-nuclear attacks are more easily accomplished and do not require taking years developing or accessing nuclear weapons.

2. They assume that not having commercial nuclear power will make them safer and eliminate certain risks or costs

Nuclear weapons existed many years before commercial nuclear power.
In 1945, there were nuclear weapons. Perhaps you heard about them. They had some obscure use at places called Hiroshima and Nagasaki.
Mid-1950s the first commercial nuclear reactors. On June 27, 1954, the USSRs Obninsk Nuclear Power Plant became the world's first nuclear power plant to generate electricity for a power grid, and produced around 5 megawatts of electric power. The world's first commercial nuclear power station, Calder Hall in Sellafield, England was opened in 1956 with an initial capacity of 50 MW (later 200 MW). The first commercial nuclear generator to become operational in the United States was the Shippingport Reactor (Pennsylvania, December, 1957).

Almost every country that has nuclear weapons gotten the weapons before they got commercial nuclear power.

There are now thousands of nuclear weapons. If the anti-nuclear people got their wish (which they won't) that all commercial reactors get shut down and no new ones get built, then the nuclear weapons and nuclear material still exist and are still a threat. Thus showing one aspect of the lack of correlation between nuclear weapons and commercial nuclear power. If the nuclear power plants get shutdown then would the US not have to secure its ports ? The US still would have to secure its ports. So how does the $7.4 billion for port security (voted for in 2006) count against commercial nuclear power ?

Does North Korea have commercial nuclear power ? No. But it has six atomic bombs or at least the material for that many.
Iran has the centrifuges running to get its nuclear bombs, but does it have a commercial nuclear reactor yet ? No.

The scenarios that anti-nuclear power people talk about is always a maximal super optimized attack against New York by terrorists. Against every other place (other than perhaps Tokyo) there is not that much concentrated and valuable population and property.

They never bother to make the terrorist connection between 5% enriched uranium and 90%+ weapons grade material. They ignore how hard it is to get from low enrichment to high enrichment. Iran, an entire nation, is taking decades to get sufficient enriched material.

How about farming and fertilizer ? Those are seemingly benign activities and material. No one seems to be protesting those things as being deadly.

Af fertilizer bomb was used for the Oklahoma City Bombing.

After the Oklahoma city bomb

Timothy McVeigh used a fertilizer bomb. Do the deaths and damage from that count against farming, trucks and fertilizer. Why not ? It is a tighter correlation than between nuclear bombs and nuclear power.

At 9:02 a.m. CST, the Ryder truck, containing in excess of 6,200 pounds (2,800 kg) of ammonium nitrate fertilizer, nitromethane, and diesel fuel mixture, detonated in front of the north side of the nine-story Alfred P. Murrah Federal Building. The effects of the blast were equivalent to over 5,000 pounds (2,300 kg) of TNT and could be heard and felt up to 55 miles (89 km) away. The attack claimed 168 lives and left over 800 people injured.

How about a scenario where a supertanker which can hold up to 500,000 tons is loaded with fertilizer explosive ? Optionally they mix in some radiological material from some hospital or other source or just mine some uranium or thorium and have that on the supertanker.

The explosion could be even bigger than the hypothetical nuclear terrorist attack.

But that kind of thing has not happened before right?


The Halifax Explosion occurred on Thursday, December 6, 1917 when the city of Halifax, Nova Scotia, Canada, was devastated by the huge detonation of the SS Mont-Blanc, a French cargo ship, fully loaded with wartime explosives, which accidentally collided with a Norwegian ship, the SS Imo in "The Narrows" section of the Halifax Harbour. The picture at the beginning of this article was the mushroom cloud from the Halifax explosion in 1917. About 2,000 people were killed by debris, fires, or collapsed buildings and it is estimated that over 9,000 people were injured. This is still the world's largest man-made accidental explosion. All buildings and structures covering nearly 2 square kilometres (500 acres) along the adjacent shore were obliterated, including those in the neighbouring communities of Richmond and Dartmouth. The explosion caused a tsunami in the harbour and a pressure wave of air that snapped trees, bent iron rails, demolished buildings, grounded vessels, and carried fragments of the Mont-Blanc for kilometres.

2,653 tons of wartime explosives.

According to estimates, roughly $35 million Canadian dollars in damages resulted (in 1917 dollars; adjusted for inflation, this is about CAD$500 million in 2007 dollars)

Terrorists do not have to do it the hard way.

A Real Nightmare Scenario

Piracy is in the news.

On November 15, 2008, Somali pirates seized the supertanker MV Sirius Star, 450 miles off the coast of Kenya. The ship was carrying around $100 million worth of oil and had a 25-man crew. This marked the largest tonnage vessel ever seized by pirates.

The Piracy Reporting Centre of the International Maritime Bureau (IMB) stated in 2004 that more pirate attacks in that year occurred in Indonesian waters (70 of 251 reported attacks) than in the waters of any other country. Of these attacks, a majority occurred in the Straits of Malacca. They also stated that of the attacks in 2004, oil and gas tankers and bulk carriers were the most popular targets with 67 attacks on tankers and 52 on bulk carriers.

MV Sirius Star is an oil tanker owned and operated by Vela International Marine. With a length overall of 1,090 feet (330 m) and a capacity of 2 million barrels (320,000 m**3) of crude oil, the ship is classified as a very large crude carrier or VLCC.

If you recall 9/11: 19 Islamist terrorists affiliated with al-Qaeda hijacked four commercial passenger jet airliners.

The two if by sea plan would seem to be terrorists infiltrate to get control of tanker or bulk carriers in a way that it is not known to not be under trusted control. Then take fertilizer or other explosive cargo from several fairly large ships into multiple ports around the world and detonate them at the same time.

The world consumption of fertilizer is about 150 million tons per year. Ammonium nitrate fertilizer is one of the most common fertilizers. Major fertilizer consumer countries are China, the United States, Brazil, India and Southeast Asian countries consumed two third of global potash fertilizer, but the output of potash fertilizer in these countries accounted for only 9.0 per cent of global output. So most fertilizer is shipped. More than 1.5 million tons of ammonium nitrate was sold in the United States in 2003. Fertilizer sales remain unrestricted across much of the United States as of 2004

If you look back at the ingredients in the Oklahoma bomb, they had fertilizer and diesel fuel. I think middle eastern terrorists can get their hands on shiploads of diesel fuel. As the piracy statistics show there are about 60-70 attacks on oil tankers each year. As noted there are usually only 12-24 person crews on the tankers and bulk carriers. Plus if Iran was backing some kind of terrorist attack, I believe they have significant amounts of oil and enough oil in tankers.

I think there is means, motive and opportunity. Multiple ship attacks that each could be ten to two hundred times as powerful as the Halifax explosion. (2600 tons of explosive in 1917 that killed 2000 and injured 9000 and devastated Halifax) I leave it as an exercise to tally the financial impact and death toll of larger attacks against multiple port or coastal cities.

In writing this up under the assumption that either places like Homeland security have already thought of it or that they should read this and consider what needs to be done. [Marines, Navy and coast guard apparently are aware of these scenarios for a few decades and apparently have measures in place to prevent it] It probably is more important than making sure people take off their shoes for airport screening. The terrorists already thought up the plane hijacking for 9-11. Hijacking ships or trucks and trains would not be a stretch.


Ammonium nitrate at wikipedia

Ammonium Nitrate disaster list at wikipedia

As noted by a commenter: the Texas City Disaster is highly relevant

The cargo ship Grandcamp was being loaded on April 16, 1947 when a fire was detected in the hold: at this point, 2600 tonnes of ammonium nitrate in sacks were already aboard. The captain responded by closing the hold and pumping in pressurised steam. One hour later, the ship exploded, killing several hundred people and setting fire to another vessel, the High Flyer, which was moored 250 metres away and which contained 1050 tonnes of sulfur and 960 tons of ammonium nitrate. The Grandcamp explosion also created a powerful earthshock and knocked two small planes flying at 1,500 feet (460 m) out of the sky. The High Flyer exploded the next day, after having burned for sixteen hours. 500 tonnes of ammonium nitrate on the quayside also burned, but without exploding, probably because it was less tightly packed.

Ammonium nitrate can explode even without mixing with diesel and other agents. Ammonium nitrate is 0.42 times as explosive as TNT by weight.

New U.S. Coast Guard regulations on the shipment of ammonium nitrate went into effect July 1, 2004. These require that each vessel or facility have a security plan, vessel or facility maintenance and security records, records of training, drills on breaches of security, establishment and training of a facility security officer, a vessel security officer for each vessel and a commanding security officer over all vessels. Vessel and facility security systems must be installed. Security training is required. The regulations list ammonium nitrate as a "Certain Dangers Cargo," which necessitates continuously patrolled restricted areas. The bottom line is that some port facilities have decided to discontinue handling ammonium nitrate, and some barge lines have decided to discontinue shipping the product due to the increased cost and liability (source of information for transportation is Green Markets Dealer Report, October 11, 2004).

The above procedures still seem insufficient if the vessel was pirated or had a terrorist crew.

A ship in 2007 with ammonium nitrate, (undisclosed amount) but the ship could hold 3000 tons, caught fire off the Australian Port of Newcastle and had visited six other ports.

Austrialian news covered it and people were upset that if the fire had gotten out of control that it would devastated Newcastle

Chuck Devore, now California state assemblyman, wrote about an ammonium nitrate ship bomb in his novel "China Attacks" as means to damage the Panama Canal for months. Chuck is aware of the risks and is in a position to let others in California and Federal government be aware of the need for more action.

Terrorist attack by sea scenario at the Foreign Policy Research Institute

In 2003, Greek authorities seized the Baltic Sky, loaded with either 750 tons of TNT or 750 tons of industrial-grade ammonium nitrate-based explosives and 140,000 detonators, renewed concerns of terrorists using ships as bombs to blow up port cities.

There was not much public discussion of the incident by officials of the USA or the Greeks.

Chinas High Temperature Nuclear Reactor Versus the USA Very High Temperature Reactor

The USA has the Very High Temperature Gen IV reactor candidate, which could have deep burn [65% of the nuclear material would be used instead of about 1% for current reactors] and temperatures up to 1000 degrees. High temperatures is efficient for providing heat for many industrial applications.

The difference between the US and China is that China will is making a high temperature reactor that they are certain that they can make now. They have a made a 10 Megawatt test reactor and start building the full scale 200 MW modular reactor starting this year (2009). They will build many copies of a conservative design. Then they will upgrade components as they build more. So China plans to get to more advanced reactors by improving the 10th-20th copies or the 21-40th copies. By the time 2025-2035 rolls around and the US may have built its first very high temperature reactor China will have upgraded their high temperature designs several times for their 300-500th factory mass produced 200MW reactors to comparable designs that have the advantage of similar early versions being in use. China will learn by building good and getting better by making more.

On Nov 5, 2008, Toyo Tanso Co., Ltd and Sumitomo Corporation received an order for graphite which is a major component for a Chinese High Temperature Gas Cooled Reactor project (HTR-PM). It is a Chinese national project and a next generation nuclear power plant construction project (HTR-PM).

Toyo Tanso and Sumitomo received the order of Toyo Tanso high purified isotropic graphite IG-110, and the order amount is several tens million dollars and over one thousands tons of graphite blocks. The delivery will be made from the middle of year 2010 till the end of year 2011

This site has provided details on the chinese High Temperature Reactor before.

China Huaneng Group, one of China's major generators, is the lead organization in the consortium with China Nuclear Engineering & Construction Group (CNEC) and Tsinghua University's INET, which is the R&D leader. Chinergy (a 50-50 joint venture of INET and CNEC) is the main contractor for the nuclear island. Projected cost is US$ 430 million, with the aim for later units being US$ 1500/kWe.

The HTR-PM will pave the way for 18 (3x6) further 200 MWe units at the same site in Weihai city - total 3800 MWe - also with steam cycle. INET is in charge of R&D, and is aiming to increase the size of the 250 MWt module and also utilise thorium in the fuel. Eventually a series of HTRs, possibly with Brayton cycle directly driving the gas turbines, will be factory-built and widely installed throughout China.

High temperature reactors can be adapted to use thorium for fuel and the plan is for factory mass produced reactors. Two year construction times and mass production driving costs down to less than half the cost of the first units. China sees these as supplemental reactors to the big reactors. They will be used in smaller cities and towns and by factories for generating industrial heat. Also, they are looking to use heat for hydrogen generation, desalination and coal liquification (at least that would be cleaner than straight coal burning).

Study of China's plans for developing nuclear power for non-electrical applications.

China is where the bulk of the world's industrial and manufacturing facilities are going. They will be driving the large scale plan for getting more nuclear power in place of coal. And they will keep building coal plants until they can make the shift.

The Chinese high temperature nuclear reactor is more suited to replace coal for industrial heating. 200 MW reactor modules that will be factory mass produced. The project received environmental clearance in March 2008 for construction start in 2009 and commissioning by 2013. Initially the existing HTR-10 had been coupled to a steam turbine power generation unit, but second phase plans are for it to operate at 950°C and drive a gas turbine, as well as enabling R&D in heat application technologies. This phase will involve an international partnership with Korea Atomic Energy Research Institute (KAERI), focused particularly on hydrogen production.

Do environmentalists see some flaw in the Chinese plans ? They are always expecting the United States not to follow through on making the 26 nuclear reactors which have had construction licenses filed with the NRC.

Is there going to be a licensing issue ? Will the leadership of China lack the will to carry through ? Will there be protests from the people who would prefer to keep using coal power ? What is the uncertainty that this will happen ?
Not one or two year delays but that by 2025-2030 we will be talking reactors of this type in the dozens if not over one hundred ?

January 23, 2009

Carnival of Space Week 87

Another Amory Lovins Big Lie: Nuclear Power Costs Too Much for Private Companies and With No Government Support None Will Be Built

Another Amory Lovins big lie, which is often repeated by various environmentalists is that nuclear power costs too much for private companies with no government support.

The lie is not that nuclear power costs large amounts of money. The big lies ignore these truths:
1. Other forms of power also cost a lot money
2. Government money massively subsidizes and supports all forms of energy
- public money is needed to prop up all of the private energy companies and industries
3. Other forms of energy are risky to develop as well

As noted in this renewable energy world link

Most thin film solar companies fail. Out of hundreds of companies only one or two companies have brought products to market in any scale.

The reality, according to Neal Dikeman, partner with VC firm Jane Capital Partners, is that only one or two thin-film projects have brought product to market in 30 years, and it's a US $100M-$200M dollar up-front investment "just to play the game and see if your product really works."

Silicon Valley investors have mistakenly bet on "really great teams" while the technology is still at a science experiment stage, he argues — investors are beginning to realize this, he thinks, and that the industry is sitting on the back end of about 5-10 years of US $100M bets. "We're going to see a bunch of write-offs coming up," he warns.

The challenge that has caught startups in this sector time and time again, Dikeman explained, is underestimating the engineering scale-up and production on a tens-of-megawatts (MW) scale.

"People always assumed that if the technology worked and the team was good, that the rest was just engineering...and so far, that has never proven to be the case," he observed, noting that there have been several hundred (thin film) companies that have tried and only two succeeded.

"The challenge has been that the engineering scale-up has been much harder than the science experiment." Citing the "black art" aspect to thin-film projects, he observed that for factories in the 30-40 MW range, what matters is getting the same yields, distributions and performance out of the second plant as was achieved in the first.

New energy costs money to develop. Tens of billions spent on wind and solar over decades to get them to this point and they are still not certain in scaling up. Any hope of scaling up is only with massive government support.

Governments are involved all over energy. It is not "all just private companies". Jerome Paris is and investor and developer of wind energy projects. In an Oil Drum article he is asking Obama for constant high levels of government subsidies. He notes that three times the wind energy industry was wiped out because of periods of insufficient of subsidies.

Solar and wind are likely to be getting $20 billion from a clean energy bill, probably going along with tens of billions more in whatever 800-1500 billion stimulus packages get passed.

The long-term extension of the renewable energy production tax credits, which would cost the government $13.1 billion over 10 years. Plus 30% tax credits for instant subsidy.

Worldwide it is about $2 trillion per year for energy spending. Hundreds of billions on subsidies and research and development. Energy costs BIG money. Why does anyone think otherwise ? All the investments are big and multi-year and often decades long. Just because you can chunk up some aspects of it into small pieces is meaningless. Yes, one set of solar panels does not take long to make but you need millions of houses with solar panels on roofs to equal one nuclear plant. It takes time to make the factories to make the panels. Doing the research and development takes time. As noted only a small percentage of the thin film solar power companies make it. The solar companies are often betting on competing specific technologies. It takes time to scale up the supply chains. Wind power takes 5,000 large wind turbines to equal one nuclear power plant. Again it takes timed to scale up the wind factory and the component supply chain and it takes ten times as much concrete and more steel for enough wind turbines to generate comparable amounts of power.

The solar and wind factories and supply chain cost a lot of money and take years to scale up. $100-200 million for each solar thin film company to make a serious play and they take a decade or so to get their R&D and then make scaled factories and try to deploy. Plus each one is competing with a hundred other variants. So which is the riskier long term investment ?

The US energy grid is going to take well over a trillion to upgrade over the next decade or two. Same for Europe's energy grid. Renewable like solar and wind need a better energy grid to have deeper penetration.

What is this "all private" BS ? By that standard you would be telling wind power developers like Jerome Paris - make it "all private" which he just told you wipes out the wind industry. Coal gets and natural gas and oil get their credits too and the biggest gift to coal is not having them pay for their waste or handle it. (the CO2, smog, particulates which would more than double the cost of coal power, it would also add 30% to natural gas)

Who is covering all the risk for coal, natural gas and oil (85+% of all of our power ?)
3 million deaths per year from air pollution.
Potential extinction from CO2 levels.
The state is not even covering it yet which is worse than paying for effective coverage.
People/citizens just die.
60,000 in the US (30,000 from coal each year, the 60K is coal and oil)
250,000+ in Europe
750,000+ in China.
This is every year.

Plus 5000 to 10,000 dead each year from coal mining.
More asthma, more heart attacks, more lung disease. 30% of the medical care is related to the increased air pollution.

Coal power is being added the fastest worldwide.
Oil over $250 billion on exploration and development each year.

US Energy subsidies over the last few decades

Energy costs with externalities included

January 22, 2009

Industrial Scale Production of Cambridge Carbon Nanotube Tethers Will Enable Hypersonic Skyhooks and Better Moon and Mars Space Elevators

There was a NASA study of hypersonic skyhooks that determined the best designs and the strength of materials needed. No show-stoppers were uncovered. However, the elements of the concept require further development and refinement and then actual implementation programs. They have to build and test hardware to make the engineering work reliably.

The recent development of centimeter length carbon nanotube tethers with a strength of 9 N/Tex [9 million newton meters/kg] is over twice as strong as any fibers ever produced before. It is believed that arbitrary lengths can be produced with a strength of 10 N/Tex at industrial scales of hundreds of tons. Therefore in a few years when the scaling up scientific work is done and the engineering has been completed to enable industrial factories then the hypersonic skyhooks will be realized.

This will mean rockets and spaceplanes that go at about Mach 8 will be able to rendezvous with rotovators. This will reduce the cost of putting things into orbit by about ten times.

Depending upon the tether system design the tether being over two times stronger will reduce the weight of the needed tether by 5 to 20 times. Keeping the weight of the system about the same would allow a lower performance hypersonic vehicle to make a rendezvous. Something that say only went mach 8 instead of mach 15.

Most of that mass ratio requirement is driven by the fact that the tether system must mass considerably more than the payload it is handling, so that, upon pickup of the payload by the tether, the payload will not pull the space tether system down into the atmosphere. The higher strength carbon nanotube tethers at higher temperatures will not be used to lower the tether system mass significantly, but instead will be used to increase the tether safety margins, lifetime, and system performance, by allowing payload pickup at lower altitudes and lower speeds, thus decreasing the performance requirements on the hypersonic airplane portion of the system.

The 2000 NASA study Assumed a Boeing Designed Hypersonic Vehicle
For the hypersonic airplane portion of the baseline HASTOL system we use an existing Boeing design for the DF-9, a dual-fuel airbreathing vehicle that has benefited from over a million dollars in NASA/LaRC and Boeing funding during prior study efforts. The Boeing DF-9 hypersonic airplane is similar to the X-43 research vehicle in shape and uses engines similar to those that will be tested in the X-43 in the Summer of 2000. The DF-9 has a 9 m (30 ft) long by 3 m (10 ft) diameter upward-opening central payload bay that can handle payloads up to 14 Mg (14 metric tons or 30,000 lb). It uses JP-fueled air-breathing turbo-ramjets up to Mach 4.5, and slush-hydrogen and air/oxygen ram/scram engines above Mach 4.5. With a full fuel load at takeoff, the hypersonic airplane masses 270 Mg (590,000 lb) or a little less than 20 times the 14 Mg payload mass, and can deliver the payload to 100 km (330 kft) altitude at an apogee speed with respect to the surface of the Earth of 3.6 km/s (12 kft/s) or approximately Mach 12. If we assume an eastward equatorial launch at the equator, the speed of the airplane with respect to inertial space is 4.1 km/s -- halfway to space.

Cheaper suborbital vehicles could be possible. Something with better performance than Scaled Composites SpaceshipTwo (which goes up to Mach 3) or if some hypersonic scramjets can be made.

Capturing the Payload

The NASA study looked at seven configurations resulted from the functional allocations between the hypersonic vehicle, payload accommodation system, and grapple assembly, focusing on methods in which to remove the payload from the hypersonic vehicle:
· Configuration 1 – Mechanical Arm on Hypersonic Vehicle
· Configuration 2 – Mechanical Arm on Grapple Assembly
· Configuration 3 – Atmospheric Vents Lift Payload out of Cargo Bay
· Configuration 4 – Payload Powers Itself Out of Cargo Bay
· Configuration 5 – Payload Ejected, Cradle/Clam Shell Mechanism captures
Free-falling Payload
· Configuration 6 – Electromagnet on Grapple Assembly Removes Payload
· Configuration 7 – Electromagnet on Payload Pulls it from Bay to Grapple Assembly

No one design solution can be offered at this early phase of development; however, several of the configuration options have shown that some more investigation needs to be made into quantifying the impacts of functional allocations within the HASTOL system architecture. Any of these could be designed to make a working HASTOL system; the questions that must be answered are, “Which one has the best reliability for the lowest operating cost,” and “Which one is more easily adapted to take advantages of technology advances?”

Configurations 1, 4, 5, and 6 represent the diverse span of functional allocations within the HASTOL architecture. Configuration 1, with the mechanical arm on the hypersonic vehicle, is a more traditional configuration that builds on a rich, past experience with Space Shuttle missions and ISS design, testing, and cost data. A revolutionary, new means of payload delivery to space should look at this traditional option (as a gauge, as well as a design solution) along with some other options that are more unconventional. Configuration 4 is the only option that requires the payload to remove itself from the cargo bay. It introduces a different type of consumable to the HASTOL system, the payload adapter, which may or may not be cost effective as well as performance effective. Configuration 5, with the payload being ejected from the cargo bay, has a simple, grapple assembly operation concept; it does need more investigation into timing, repeatability, and capture impact loading on the tether tip. Configuration 6, with the electromagnetic grapple, should be investigated as a soft docking design solution. A less powerful electromagnet could be used to soft dock the grapple to the payload before a hard dock,using any of the above hard dock suggestions, captured the payload. Though a mechanical arm on the orbiting grapple assembly is viewed as unnecessarily complex, the tether-based solution to increasing the capture window should be investigated for any type of grapple assembly that is used. The operational dynamics are a little more complex with this solution, but it has a great chance of increasing the capture opportunity window, especially when teamed with other design solutions aiming at that same end.

Rotovator Variants

A rotovator is a tether that rotates more than once each time it orbits around a planet or moon. Rotovators rotate in the same sense as they orbit such that the lower tip has a retrograde motion relative to the center of gravity. Rotovators in almost all ways have the same benefits as skyhooks. However, due to the retrograde velocity, the lower tip can achieve a specified Mach number with a shorter tether. This, despite the rotational forces, produces lower stresses in the tether so that lower strength to weight ratio materials can be used for the same results.

The new Cambridge tethers would perform better than the 2X strength tether and would be 3 times the strength of Spectra 2000. You now always choose the longest tether, which has the best performance and the design still weight is still about at the level of the shortest or close to shortest Spectra 2000 design.

The CardioRotovator concept consists of a Tether Central Station in an elliptical orbit, with a single long tapered tether. The tether rotation rate is chosen to be exactly twice the orbital period. The CardioRotovator gives somewhat better results than the Rotovator. In general, however, the length of the CardioRotovator tether is much longer than the length of the Rotovator tether, which leads to greater concern about collisions of the tether with other objects in space. This concern is partially compensated by the fact that the CardioRotovator tether spends most of its time at high altitudes where there is less traffic.

Two Stage Tethers - More Complicated Design - But Lighter

Carbon nanotube tethers are expected to maintain strength better at higher temperature ranges

Lunar Space Elevator
Better space elevators for the moon will be possible as well. Note: a lunar space elevator can be built now from existing high volume fibers.

A lunar space elevator using existing high-strength composites with a lifting capacity of 2000 N at the base equipped with solar-powered capsules moving at 100 km/hour could lift 584,000 kg/yr of lunar material into high Earth orbit.

Rather than waiting for carbon nanotubes to be developed into structural materials, we can use existing high-strength materials such as T1000G carbon fiber, or, with protective coatings, Spectra 2000, Zylon, or Magellan M5. These all have breaking lengths of several hundred kilometers under 1 g, and would require taper ratios of less than ten between the base and the Lagrangian balance points.

Current composites [before Cambridge Material is available] have characteristic heights of a few hundred kilometers, which would require taper ratios of about 6 for Mars, 4 for the Moon, and about 6000 for the Earth.
The Cambridge taper ratios would be about 3 for Mars, 2 for the Moon and 500 for the Earth.

The new Cambridge material only has a density of 1000 and GPA of 9 to 10 so it will still be 70% better than an improved M5 fiber. About a 900 km breaking height.

Mars-Phobos Space Elevator
A Mars Space elevator could be made far better and lighter with the new materials

The approach would take advantage of the unique configuration of Mars and its moon Phobos to make a transportation system capable of lifting frequent payloads from the surface of Mars to space and accomplishing this at a low cost. Mars would be used as the primary location for support personnel and infrastructure. Phobos would be used as a source of raw materials for space-based activity, and as an anchor for tethered carbon-nanotube-based space-elevators to help raise people and payloads from Mars to space. One space-elevator would terminate at the upper edge of Mars’ atmosphere (6,000 km long). This terminus would only be moving about 0.52 km/s relative to the surface. Small craft could be launched from Mars’ surface at a modest velocity and small rockets used to rendezvous with and attach the craft to the moving elevator tip. Staged cable lifts could then raise modules from the craft to Phobos, then the empty craft detached and landed with a paraglider. Landing on Mars from space could be done directly with a combination of aerobreaking and use of a large paraglider to land.

Another space-elevator would be extended outward of Phobos an additional 6,000 km to launch craft toward the Earth/Moon system or the asteroid belt. Release at the outward elevator tip velocity of 3.52 km/sec would result in a hyperbolic velocity of about 2.6 km/sec. This is the Hohmann elliptical transfer velocity needed to reach the Earth/Moon system, and is also nearly the transfer velocity needed to reach the inner edge of the asteroid belt. This velocity boost would considerably reduce onboard propellant needs for space transportation. This outward elevator tip could also be used to catch arriving craft, with staged elevators also bringing the vehicles or carrier modules from the vehicles to Phobos.

These space-elevators would allow low cost movement of people and supplies from Mars to Phobos and from Phobos to interplanetary space. This approach would allow Mars to be used to support an extensive space industry. In addition, large quantities of material obtained from Phobos could be used to construct space habitats and also supply propellant and material for space industry in the Earth/Moon system as well as on and around Mars.

IEEE Spectrum Technology Winner and Loser Pick Advice - Bet the Trifecta to Lose and the Favorite to Win

IEEE article has another article where they pick some of technology's winners and losers. I have left comments on some of their other articles asking them to more clearly define what a win for a winner would look like and what a loss for loser would look like. Also, there picks this year basically break down to small early stage companies are risky and more prone to failure and big companies with military backing are safer and likely to succeed if they are scaling up deployment with large financial backing this year.

They claim 17 out of 20 past picks for winners panned out. Given the conservative nature of their "winning picks" it is not surprising that they have a high ratio of successful picks. They also do not say with clarity what that means in a precise way for third parties to judge if they got it right. IEEE advice if are you are just counting win/loss picks then bet the trifecta to lose and the favorite to win.

What does it mean for Intel's Larrabee chip to win ?

You have the dominant semiconductor company making another new line of chips. If they don't introduce Larrabee then that could be viewed as a failure but what is the chance of that ? If they introduce it and it is second to one of Nvidia's GPU chips in market share is that a failure ?

Microsoft introduced Vista and many people view it as a failure but it still has 10% market share. If Technology Review had picked it to win or lose how would we know if they were right ?

What does their list of winners/losers for this year show ?

Engineered geothermal will be a winner if australian turns on a nearly complete 1 megawatt reactor ?
Intel will win with Larrabee ?
Darpa will win with Prosthetic arms that are already on and bieng used by some people ?
10 Ghz radar will be successful when the military already has field tests and they are just moving to battlefield deployments.
quantum dot lasers will be a market success when Fujitsu has already picked it for deployment ?

Versus losers which are all early stage and smaller ventures like :
An amphibious car startup

Blacklight power

Brain computer interfaces for games

Strawberry picking robots (maybe $1.5 million budget and currently only works in greenhouses)
- humans can do it better but if it finds a small niche market in japan and other places is that a failure

Face recognition for advertising TV screens in public places is a loser. Is it a loser only if the Minority Report situation does not happen or is it a loser if there are not more smart billboards than the one that has been on the 101 highway in the San Francisco bay area ?

E-fuel startup making ethanol from sugar is a loser.

There is not much risk that IEEE is taking with their picks. It is like saying if someone is playing blackjack in a casino and they say staying on 20 is a winner and taking a hit on 19 or higher is a loser. Plus they will not define an amibiguous draw as being winning or losing. Wow that is insightful. How do they get their great track record ?

Let me make some comparable non-technology predictions:
Winner: The Boston Celtics (36 wins, 9 losses) will make this years NBA playoffs.
Loser: Memphis Grizzles (11 wins, 30 losses) will make it this years NBA Finals.

Understanding Strength of Materials and History of Improvement

This article will go over some basic background about tensile strength of material and then discuss historic material strength improvement to understand what industrial production of new carbon nanotube tethers relates to past improvements in strength of materials.

Understanding Tensile Strength of Material and the Measurement Units
A Gigapascal is unit of measure for strength of material. The strength of tethers (ribbons or rope) is usual the tensile strength. Tensile strength is how much force is needed to pull the tether until it breaks/fails. How strong a tether for a given amount or density of material is important. Grams per cubic centimeter (g/cc or g/cm**3) are used to measure the density. 1 gram per cubic centimeter is the density of water

Specific tensile modulus
Tensile modulus related to the specific gravity.
It is expressed in N/tex (1 N/tex = 10.2 g/dtex or 11.3 g/den).
It is calculated by the relation:
Specific tensile modulus (N/tex) = Tensile modulus (GPa) / Specific
gravity (g/cm3)

One N/Tex is the same as One GPa per gram per cm3 is the same as one mega Yuri.

The units for measureing specific strength (or tenacity) are confusing - traditionally, people use either GPa-cc/g for the former, and N/Tex for the latter. These two units are the same in fact, and are equal to 1E6 N-m/kg [one million newton meters per kilogram], which is what the pure metric unit should be - force per linear density.

To end confusion once and for all, we propose to name the pure metric unit for both specific strength and tenacity as a Yuri (in honor of Yuri Aatsutanov), and so a tether with a linear tensity of 0.001 kg/m that breaks at 1000 N will have a breaking strength of 1 Mega Yuri.

Tensile Strength of Different Material
Wood 0.001 N/tex
Steel 0.05 N/tex
Alumina 0.5 N/tex
Nylon 0.84 N/tex
Spider silk 1 N/tex
E-glass 1.4 N/tex
S-glass 1.8 N/tex
Kevlar #29 has 1500 denier and 1.42 grams per cc of material
Kevlar #29 has 2.03 N /Tex
Kevlar #49 has 2.08 N/Tex
Spectra 1000 has 3.10 N/Tex
The strongest fibers ever before this had gotten to about 4.1 [Zylon] N/Tex

Steel has strength properties [not necessarily just tensile strength] that are two to three times more than cast iron.
Titanium is about half the weight of steel and a little stronger, plus it can remain strong at higher temperatures.

Carbon Nanotube fiber with 10 N /Tex has FIVE times the strength of common Kevlar.
The strength difference is more than the difference between Kevlar and Nylon.

So we are talking about moving from the age of iron to the age of steel or even from bronze the copper/brass ages to the iron age was also a similar step up in material strength. [Bronze was stronger than iron. The switch to iron was because of tin to make bronze became too expensive. The ages also had to do with shifts in society, technology and culture that coincided with the shifts in materials.]

If we get the 30 N/Tex that is like the step from copper up to steel. Researchers believe that 20-30N/Tex carbon nanotube tethers are possible.

Being able produce the new carbon nanotube tethers/material in large volumes and at affordable prices is vital for realizing the large potential impact on civilization.

100 kilometer high towers.
1800 kilometer long orbiting tethers.

Being able to go mach 10 with a rocket and then handoff to a tether means that cargo/payload becomes 1/3 of what the rocket is hauling instead of 1% or less.

References on material strength:

Tensile load support for cables

Google book on material strength

This link has is another table of materials with costs (includes glass and other more common material)

Educational reference that teaches polymer science and material strength

Historic Periods Dominated By Particular Material
Originally archeological classifications had the stone, bronze and iron age. Copper and other ages were added later.

Another set of strengths and elasticity of materials tables.

Tensile Strength
Brass (66% Cu, 34% Zn) (cast) 150–190 MPa
Brass (rolled) 230–270 MPa
Copper (cast) 120–170 MPa
Copper (rolled) 200–400 MPa
Iron (cast) 100–230 MPa
Iron (wrought) 290–450 MPa
Steel (castings). 400–600
Steel (mild) (0.2% C) 430–490
High-carbon spring steel:
(annealed 700–770

The Stone Age

The Stone Age is a broad prehistoric time period during which humans widely used stone for toolmaking. Stone tools were made from a variety of different kinds of stone. For example, flint and chert were shaped (or chipped) for use as cutting tools and weapons, while basalt and sandstone were used for ground stone tools, such as quern-stones. Wood, bone, shell, antler and other materials were widely used, as well. During the most recent part of the period, sediments (like clay) were used to make pottery.

The Copper Age

The copper age is a phase in the development of human culture in which the use of early metal tools appeared alongside the use of stone tools.

The Bronze Age

Bronze was also stronger than iron, another common metal of the era, and quality steels were not available until thousands of years later. Nevertheless the Bronze Age gave way to the Iron Age as the shipping of tin around the Mediterranean Ocean ended during the major population migrations around 1200 - 1100 BCE, which dramatically limited supplies and raised prices. Bronze was still used to a considerable extent during the Iron Age, but for many purposes the weaker iron was sufficiently strong to serve in its place. As an example, Roman officers were equipped with bronze swords while foot soldiers had to make do with iron blades.

Copper-based alloys have lower melting points than steels and are more readily produced from their constituent metals. They are comparable to steel in density, most copper alloys being only about 10 percent heavier, although ones with a lot of aluminium or siliconSilicon is the chemical element in the periodic table that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. It is the second most abundant element in the Earth's crust, making up 25 may be slightly less dense than steel. Bronzes are softer and weaker than steel, and more elasticThere are separate articles about elasticity in economics, and about British rubber bands. In solid mechanics, the adjective elastic characterises both collisions between, and deformations of, physical objects. A collision is perfectly elastic if the tota, though bronze springsA spring is a flexible elastic object used to store mechanical energy. Springs are commonly made out of steel or brass. Types of spring The most common types of spring are: the helical or coil spring (made by winding a wire around a cylinder) this is a ty are less stiff (lower energy) for the same bulk. Bronzes resist corrosionCorrosion is the destructive reaction of a metal with another material, e. oxygen, or in an extreme pH environment (either acidic or basic). The corrosion product is a mix of oxide and salts of the original metal. Corrosion is the primary means by which m (especially seawater corrosion ) and metal fatigue better than steel. Bronzes also conduct heat and electricity better than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than nickelThis article is about the element nickel. See also nickel (U. coin) and nickel (Canadian coin). Nickel is a metallic chemical element in the periodic table that has the symbol Ni and atomic number 28. Notable characteristics Nickel is silvery white metal-base alloys.

Iron Age

In archaeology, the Iron Age was the stage in the development of any people in which tools and weapons whose main ingredient was iron were prominent. The adoption of this material coincided with other changes in some past societies often including differing agricultural practices, religious beliefs and artistic styles, although this was not always the case.

In history, the Iron Age is the last principal period in the three-age system for classifying prehistoric societies, preceded by the Bronze Age. Its date and context vary depending on the country or geographical region.

Scientists Unlock Possible Aging Secret in Genetically Altered Fruit Fly

Researchers established that the mutated Indy gene helped fruit flies live longer. They have now explored what mechanisms lead to the longer life of the fruit fly. (Indy flies’ life span increased from an average life span of about 35 days to 70 days.)

The researchers decided the best way to try to understand how the Indy mutation might extend life span would be to study the differences in molecular changes between the Indy flies and normal flies throughout their entire life. By comparing the expression level of all genes in the Indy flies to that of normal flies, they made an important finding. Some of the genes involved in generating the power necessary for normal cell life were expressed at lower levels in the Indy flies.

This led to a decrease in free radicals and the damage they normally cause in the cell, but it surprisingly did not decrease the overall amount of energy in the cell. These studies provide evidence for possible interventions that can alter metabolism in a way that reduces free-radical or oxidative damage and extends life span, without some of the negative consequences normally associated with a change in metabolism.

As readers here know separately Genescient has a population of fruit flies that live 4.5 times longer than normal and have identified 700+ genes that are correlated to aging. Genescient Co-founder and Chairman Gregory Benford believes that they can use supplements and already FDA approved drugs and ingredients to stimulate those genes to rapidly get life extending and health enhancing effects widely available.

Here is the abstract of the research paper

Long-lived Indy [I'm Not Dead Yet] induces reduced mitochondrial reactive oxygen species production and oxidative damage

Decreased Indy activity extends lifespan in D. melanogaster without significant reduction in fecundity, metabolic rate, or locomotion. To understand the underlying mechanisms leading to lifespan extension in this mutant strain, we compared the genome-wide gene expression changes in the head and thorax of adult Indy mutant with control flies over the course of their lifespan. A signature enrichment analysis of metabolic and signaling pathways revealed that expression levels of genes in the oxidative phosphorylation pathway are significantly lower in Indy starting at day 20. We confirmed experimentally that complexes I and III of the electron transport chain have lower enzyme activity in Indy long-lived flies by Day 20 and predicted that reactive oxygen species (ROS) production in mitochondria could be reduced. Consistently, we found that both ROS production and protein damage are reduced in Indy with respect to control. However, we did not detect significant differences in total ATP, a phenotype that could be explained by our finding of a higher mitochondrial density in Indy mutants. Thus, one potential mechanism by which Indy mutants extend life span could be through an alteration in mitochondrial physiology leading to an increased efficiency in the ATP/ROS ratio.

January 21, 2009

Harvard Makes Topical RNAi Treatment That Can Effectively Stop the Transmission of Herpes

Harvard medical school has a topical treatment (a cream) that is based on RNAi (RNA interference) which can eliminate herpes virus even one week after infection to effectively stop the transmission of herpes. This was proven with mice and will be moving to human trials.

A topical treatment disables key proteins necessary for the herpesvirus to infect and thrive in the host. Using a laboratory strategy called RNA interference, or RNAi, the treatment cripples the virus in a molecular two-punch knockout, simultaneously disabling its ability to replicate, as well as the host cell’s ability to take up the virus. The research, conducted in mice, demonstrated that the treatment is effective when applied anywhere from one week before infection to a few hours after virus exposure.

The World Health Organization estimates that approximately 536 million people worldwide are infected with herpes simplex virus type 2 (HSV-2), the most common strain of this sexually transmitted disease. Women are disproportionately affected. This is especially serious, since the virus can easily be passed from mother to child during birth, and untreated infants face high risks of brain damage and death. While HSV-2 alone isn’t life-threatening in adults, infection increases vulnerability to infection with other viruses such as HIV. In fact co-infection with HSV-2 is the most important co-factor globally for sexual transmission of HIV infection. If the findings from this study are successfully replicated in human trials, people worldwide—particularly women—will have a new and powerful means of protecting themselves from this harmful pathogen.

In early 2008, there was a separate Harvard developed Herpes vaccine. This is in preclinical trials.

Cambridge Making Carbon Nanotubes Ribbons at Centimeter Lengths with 9 Gpa Strength, Which is Four Times Stronger than Kevlar

The Times UK reported claims that Alan Windle's team at Cambridge University had created the world’s strongest ribbon. I finally tracked down specifics of this work.

UPDATE: Details on hypersonic skyhooks/rotovators [orbital ropes] that would be enabled with these materials as well as lunar and Mars space elevators.

Background on strength of materials, units of measure and the historical progress in improving strength of materials

From a press release of the 2nd International Conference on Space Elevator and Carbon Nanotube Tether Design in Luxembourg on Dec 14, 2008 Cambridge is making 9 Gpa strength material with a density of one gram per cc [same density as water] and believe that they can increase the strength to 10 GPa and make it in meter lengths in time for a space elevator tether competition in late April, 2009. [Competition tethers must be 2 meters long and a maximum of 2 grams.] They are also scaling this up to industrial scale over the next few years. Space elevators are closer as well as other tether applications like orbital skyhooks. Industrial scale at 10GPa means lighter, stronger cars, planes, bikes, spaceships, armor. If they can control the electrical properties then you can transform the electric grid and wiring. Key parts of the populist vision of molecular nanotechnology would be happening when this is scaled to industrial levels.

Prof. Windle’s research team at the University of Cambridge seems to lead the way towards super strong tethers. As Cambridge researcher Dr. Marcelo Motta pointed out they are currently able to produce almost cm long individual macroscopic CNT threads with tensile strength of up to 9 N/tex which compares to about 9 GPa at the given density of their material. Scaling up the Cambridge laboratory process to industrial production and spinning these threads, ropes and cables with 10 GPa should be soon feasible. As a possible next step Dr. Motta announced the likely participation of the Cambridge team in the coming Strong Tether Challenge hosted by NASA/Spaceward in 2009, as explained by Dr. Bryan Laubscher of Odysseus Technologies.

The Cambridge material is two and half times stronger than Spectra 2000 and Zylon which are used for bullet proof vests. It is about four times stronger (strength/weight) than the best Kevlar. A table of the strength of materials. [Look at Longitudinal Tensile Strength/ Density]

From a European Spaceward Association presentation on Dec 7, 2008: At Cambridge University, we have recently introduced a method for the spinning of pure carbon nanotube fibres directly from the gas phase of a chemical vapour deposition reactor. The major benefit of this process is the ability to continuously collect the pure and uniform nanotubes as a transparent thin-film or as a high-performance fibre. While the best strength (2.5 N/tex) and stiffness (160 N/tex) promise competition for established carbon fibres, the maximum energy absorbed at fracture (up to 100 J/g) is considerably higher. When tested in small gauge lengths, and thus less sensitive to defects arisen from instabilities in the production line, these fibres show remarkable combination of tensile strengths (5-10 N/TEX), stiffness and toughness which makes them the strongest materials ever tested. In this presentation I will show in detail how these fibres are produced and discuss how their properties can still be significantly improved without the need to apply any extra additives or post-processing. These challenges will be set against the scaling-up plan already under development.

The Times UK claims Alan Windle's team at Cambridge University has created the world’s strongest ribbon: a cylindrical strand of carbon that combines lightweight flexibility with incredible strength and has the potential to stretch vast distances.

The Cambridge team is making about 1 gram of the high-tech material per day, enough to stretch to 18 miles in length. “We have Nasa on the phone asking for 144,000 miles of the stuff, but there is a difference between what can be achieved in a lab and on an industrial level,” says Alan Windle, professor of materials science at Cambridge University, who is anxious not to let the work get ahead of itself.

The Cambridge team have found a way of combining separate nanotubes into structures that bind to form longer strands.


Also from the Luxembourg conference:
The long awaited presentation by Prof. Nicola Pugno from Politecnico di Torino, Italy, on the role of defects in the design of a space elevator cable brought clarifications on the thermo dynamical limits of designing such a super strong mega cable. According to Prof. Pugno, even applying healing processes fabricated pure CNT cables will never be without defects. Based on quantized fracture mechanics already an exceptional small defect like a single nano pin hole caused by a missing carbon atom in the hexagonal molecule of a CNT results in a strength reduction of about 20% from the theoretical value for the single nanotube! Extrapolating this to the mega cable of the space elevator, where larger nano holes and nano cracks are unavoidable the actually achievable strength is about one third of the theoretical strength. Assuming a theoretical strength of 100 GPa for a mega tether this means an actual value of 30 GPa with an upper thermo dynamical limit at 45 GPa. Following Prof. Pugno’s proposal efforts should focus on designing a system with a flaw tolerant mega cable of 10 GPa which should be practical on the multi scale. Implications for the design of the space elevator system are an increased taper ratio and mass of the tether, reducing payload capacity.

The history of carbon nanotube work at Cambridge from 2004 to 2008.

Strength of Material and Tapering of the Space Elevator

Here is the italian paper on theoretically lower maximum strength for large scale carbon nanotubes.

the taper ratio of 10 GPa g/cc goes to 613. While the taper for 30 Gpa g/cc is 7 (with 20% safety margin). So you need about 80 times more material for the elevator.

But lunar and Mars space elevators would still be reasonable and economic.

Here is a paper that discusses ribbon mass and taper ratios with different strength of material.

20 GPa g/cc is about 100 taper.( with 2 times safety margin)
20 GPa g/cc with no safety margin is 12 taper.
20 GPA g/cc with 20% safety margin is 20 taper.

Higher taper means a lot more material at the top to support the weight without breaking and then thinning out toward the bottom.

eg. A taper of 20 means 20 meters wide at the top to hold 1 meter wide at the bottom.

10 GPa g/cc [MYuri's] is better than anything else. Stronger than M5 fiber, Zylon, Spectra 2000 etc... Carbon nanotube fibers would finally be the best in practice. As the claim states the strongest ribbon ever. 10 GPa g/cc would still fall short of good enough for a practical earth space elevator. But even if theoretical maximums are reached, earth space elevators push what is possible with materials. Thus I like space piers and really good orbital skyhooks more which are very useful for lowering the cost of space access and less demanding. Plus some really nice tall towers would be possible.

Properties of diamond
Observed tensile strength up to 60 GPa observed and 90-250 GPa in theory. Density 3.5 grams/cc
17-54 MYuri but it is brittle and in other ways unsuitable for space elevators.

January 20, 2009

Micron Gap Thermal Photovoltaics

MTPV, a startup based in Boston that has raised $10 million, says that it has developed prototype micron-gap thermal photovoltaics that are large enough for practical applications.

Thermal photovoltaics use solar cells to convert the light that radiates from a hot surface into electricity. The first applications will be generating electricity from waste heat, eventually the technology could be used to generate electricity from sunlight far more efficiently than solar panels do. In such a system, sunlight is concentrated on a material to heat it up, and the light it emits is then converted into electricity by a solar cell.

In a thermal photovoltaic system, light is concentrated onto a material to heat it up. The material is selected so that when it gets hot, it emits light at wavelengths that a solar cell can convert efficiently. As a result, the theoretical maximum efficiency of a thermal photovoltaic system is 85 percent.

In practice, engineering challenges will make this hard to attain, but DiMatteo says that the company's computer models suggest that efficiencies over 50 percent should be possible. The prototypes aren't this efficient: they convert about 10 to 15 percent of the heat that they absorb from the glass-factory exhaust into electricity, which DiMatteo says is enough to make the devices economical.

Thermal Photovoltaics could be superior to both regular photovoltaics and to thermal electrics in terms of efficiency of converting heat or sunlight to electricity.

In a conventional TPV system, most of the photons generated in the heated material are reflected back into the material when they reach its surface; it's the same phenomenon that traps light in fiber-optic cables. When the solar cell and the heated material are brought close together, so that the gap between the two is shorter than the wavelength of the light being emitted, the surface no longer reflects light back. The photons travel from one material to the other as if there were no gap between them. The close spacing also allows electrons on one side of the gap to transfer energy to electrons on the other side. (A vacuum between the heated material and the solar cell maintains a temperature difference between the two that is required to achieve high efficiencies.) Since the heated material emits more photons, the solar cell can generate 10 times as much electricity for a given area, compared with a solar cell in a conventional TPV.

That makes it possible to use one-tenth as much solar-cell material, which cuts costs significantly. Alternatively, it makes it possible to generate more power at lower temperatures, which Peter Peumans, a professor of electrical engineering at Stanford University, says is one of the key advantages of the approach. Conventional thermal photovoltaics can require temperatures of 1,500 °C, he says. The first prototypes from MTPV work well at less than 1,000 °C, and DiMatteo says that, in theory, the technology could economically generate electricity at temperatures as low as 100 °C. This large temperature range could make the technology attractive for generating electricity from heat from a variety of sources, including automobile exhaust, that would otherwise be wasted.

But Peumans says that the technology has a trade-off: because the heated material and solar cell are placed so close together, it's not possible to put a filter between them to help tune the wavelengths of light that reach the solar cell. This could limit the ultimate efficiencies that the system can reach.

Chris Heward, Who Headed the Kronos Foundation, Died Jan 11, 2009

Alan Windle Past Carbon Nanotube Work Suggests Recent Announcement Could be Huge

Carbon nanotube fiber on spindle from Alan Windle group. 2007 picture

The Times UK claims Alan Windle's team at Cambridge University has created the world’s strongest ribbon: a cylindrical strand of carbon that combines lightweight flexibility with incredible strength and has the potential to stretch vast distances. There may have been no advance or minimal advance from the Dec 7, 2008 European Spaceward presentation on the Cambridge carbon nanotubes.

UPDATE: Found the specifics. Strength 9 GPa in centimeter lengths which they are scaling to meter lengths and 10GPa in a few months and to industrial scale in a few years This material is 2.5 times stronger than Spectra 2000 (by strength/weight) and four times stronger than Kevlar.

Prof Alan Windle has claimed to have made the strongest ribbon of material ever.

This could mean material suitable for space elevators in 5 to 10 years.

Spectra 2000 fiber used in body armor and stronger than Kevlar has: Strength 3.5 GPa and Density: 0.97 g/c

Carbon nanotubes on a molecular scale or in small quantities have strength up to 70-200 GPa. 20 to 55 times stronger than Spectra 2000.

The new work is bringing the large scale strength of carbon nanotubes up to 2.5 to 10 GPa. From a little less strong than Spectra up to 3 times stronger.

What does it mean ?
- Better military and police armor.
- Better tethers for space (shorter versions of the space elevator)
- wider use of carbon nanotubes for reinforcing many things.
- When production volumes increase they can be used to make lighter cars and planes so that they are more fuel efficient.

Here is a review of announcements from Alan Windle's team from 2004 to 2008.

New Scientist Reported in 2004, Alan Windle's group had made 100 meter long carbon nanotube thread but the threads were not strong. If Alan Windle has made the world's strongest ribbon and these threads are still 100 meters long or more then this would be a monster breakthrough.

MIT Technology Review reported in 2007 that Alan Windle had made stronger carbon nanotubes stronger.

Alan Windle, a professor of materials science at the University of Cambridge, in England, made and tested the new nanotube fibers along with researchers at the Natick Soldier Research Development Center, in Massachusetts. Windle and his colleagues tugged on the nanotube fibers, finding that the weaker ones snapped at stresses around one gigapascal, making them comparable to steel, gram for gram.

The better-performing carbon-nanotube fibers broke at around six gigapascals, beating the strengths that manufacturers report for materials used in bullet-proof vests, such as Kevlar. These nanotube fibers matched the highest reported strengths for a couple of the strongest commercially available fibers, Zylon and Dyneema, also used in bullet-proof vests. A lone, extremely strong nanotube fiber was off the charts, reaching nine gigapascals of stress--far beyond any other reported material--before breaking. Earlier work with carbon nanotubes has produced fibers that withstand at most three gigapascals.

In 2008, Alan Windle was making 20 gigapascal strength carbon nanotubes but only for gauge length sections [less than one millimeter]

Both Nanocomp and Dr. Alan Windle’s group at the University of Cambridge are making some exciting materials by continuous-draw processes, and a number of other groups are working on some exciting other approaches such as spinning from nanotube forests grown on silicon wafers. [from 2008]

Nanowerk describes the Alan Windle continuous spin process from late 2007.

As in the proverb 'A chain is only as strong as its weakest link', the performance of a CNT fiber depends on the weak points along its length, caused by defects on its internal structure. The major challenge for materials engineers therefore is to develop a production process that avoids these defects and makes CNT fibers suitable for commercial applications.

"We have developed successful strategies to avoid particulate defects amongst the network of nanotube bundles forming the fibers" Dr. Marcelo S. Motta, a Research Associate in Windle's group, tells Nanowerk. "Recent improvements in our process have enabled us to spin continuously with iron contents down to 25 ppm. At present, these fibers are spun at a rate of 5–25 meters per minute, with diameters in the range 2–20 µm. Because they are so thin, a kilometer of fiber weighs much less than a gram."

From a European Spaceward Association presentation on Dec 7, 2008: At Cambridge University, we have recently introduced a method for the spinning of pure carbon nanotube fibres directly from the gas phase of a chemical vapour deposition reactor. The major benefit of this process is the ability to continuously collect the pure and uniform nanotubes as a transparent thin-film or as a high-performance fibre. While the best strength (2.5 N/tex) and stiffness (160 N/tex) promise competition for established carbon fibres, the maximum energy absorbed at fracture (up to 100 J/g) is considerably higher. When tested in small gauge lengths, and thus less sensitive to defects arisen from instabilities in the production line, these fibres show remarkable combination of tensile strengths (5-10 N/TEX), stiffness and toughness which makes them the strongest materials ever tested. In this presentation I will show in detail how these fibres are produced and discuss how their properties can still be significantly improved without the need to apply any extra additives or post-processing. These challenges will be set against the scaling-up plan already under development.

The Times UK claims Alan Windle's team at Cambridge University has created the world’s strongest ribbon: a cylindrical strand of carbon that combines lightweight flexibility with incredible strength and has the potential to stretch vast distances.

The Cambridge team is making about 1 gram of the high-tech material per day, enough to stretch to 18 miles in length. “We have Nasa on the phone asking for 144,000 miles of the stuff, but there is a difference between what can be achieved in a lab and on an industrial level,” says Alan Windle, professor of materials science at Cambridge University, who is anxious not to let the work get ahead of itself.

The Cambridge team have found a way of combining separate nanotubes into structures that bind to form longer strands.

How long is the carbon nanotube fiber ? could be 100 meters or longer
How strong is this carbon nanotube fiber ? Should be over 6 to 9 gigapascals which was the 2007 level. Windle still says that space elevator strength material is still 5-10 years away. So the new material could be in the 6 to 9 gigapascal (5-10 N/Tex) range if they have solved more of the defect issues. We will update when information becomes available. Awaiting definitive scientific paper or announcement with key metrics.

This could be a pretty monster development and the claim NASA is calling him would be correct if he has 100 meter + and 6-9 gigapascal strength material.

UPDATE: Found the specifics. Strength 9 GPa in centimeter lengths which they are scaling to meter lengths and 10GPa in a few months and to industrial scale in a few years This material is 2.5 times stronger than Spectra 2000 (by strength/weight) and four times stronger than Kevlar.

Spaceward has been tracking carbon nanotube bulk strength progress.

There are many "less than space elevator applications" for that kind of material.

Space Elevator blog also discusses this new information but also does not have specifics yet.

A previous abstract from a 2007 research paper "High-Performance Carbon Nanotube Fiber" with Windle as one of the writers.

BBC had coverage on Windle's work back in 2007

The fibre created in Cambridge is very strong, lightweight and good at absorbing energy in the form of fragments travelling at very high velocity.

Our fibre is up there with the existing high performance fibres such as Kevlar", said Professor Windle.

But he added: "We've seen bits that are much better than Kevlar in all respects".

A hydrocarbon feedstock, such as ethanol, is injected into the furnace along with a small amount of iron-based catalyst.

Inside the furnace, this feedstock is broken down into hydrogen and carbon. The carbon is then chemically "re-built" on particles of iron catalyst as long, thin-walled nanotubes.

To the eye, this "elastic smoke" looks a bit like an ever-expanding dark "sock".

To begin winding it up, a rod is inserted into the furnace from below to grab one end of the sock and yank it down. This stretches the sock into a filament that can be wound up continuously on a reel.

The researchers are currently seeking funds to investigate whether the method can be upgraded from a laboratory to an industrial process.

Cambridge Enterprise Limited, the commercialisation office of the University of Cambridge, filed an initial patent application in July 2003.

It has now granted a licence to Q-Flo Limited, a university spin-out company, which will exploit the technology.

Alan Windle's website at Cambridge University

Breakthrough For Faster Study of Genetic Diseases

A cure for debilitating genetic diseases such as Huntington's disease, Friedreich's ataxia and Fragile X syndrome is a step closer to reality, thanks to a recent scientific breakthrough. A plant model for genetic diseases with a relatively short lifespan would allow scientists to study DNA mutations over several generations, Dr Balasubramanian said.

Dr Sureshkumar Balasubramanian at The University of Queensland's School of Biological Sciences and Professor Dr Detlef Weigel at the Max Planck Institute for Developmental Biology in Germany identified an expansion of a repeat pattern in the DNA of the plant Arabidopsis thaliana that has striking parallels to the DNA repeat patterns observed in humans suffering from neuronal disorders such as Huntington's disease and Fredereich's ataxia.

Lead researcher from UQ, Dr Balasubramanian, said being able to use the plant as a model would pave the way toward better understanding of how these patterns change over multiple generations.

"It opens up a whole new array of possibilities for future research, some of which could have potential implications for humans," Dr Balasubramanian said.

The types of diseases the research relates to, which are caused by "triplet repeat expansions" in DNA, become more severe through the generations but were difficult to study in humans due to the long timeframes involved.

The study, called "A genetic defect caused by a triplet repeat expansion in Arabidopsis thaliana", also had implications beyond human diseases, Dr Balasubramanian said.

While the DNA patterns were previously only seen in humans, current findings have shown the patterns occur in in distant species such as plants, providing new scope for researchers in all disciplines of biology.

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