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No end to new materials with super-strength

October 10, 2013

From the days of the alchemists and then the metallurgists who mixed different materials – often in the molten state – and then to the chemists we have now moved into the age when materials are designed in the lab to have desired properties. The challenge then is to synthesise the desired composition with the atomic structure required and then to devise manufacturing processes for the materials.

“A material called carbyne could be stronger even than graphene or diamond, according to researchers who have calculated its properties”, reports the BBC.

Carbyne is a chain of carbon atoms held together by double or alternating single and triple chemical bonds.

In their paper, Boris Yakobson and colleagues from Rice University in Houston show that carbyne’s tensile strength – the ability to withstand stretching – surpasses that of “any other known material” and is double that of graphene, the flat sheet of carbon atoms that is often held up as a “supermaterial”.

They also calculated that carbyne has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.

It should display a number of other useful properties say the researchers. For example, it could be turned into a magnetic semiconductor (these are materials with electrical conductivity between that of a metal and an insulator like glass) and could be used as a sensor to detect twisting.

Some scientists have reported synthesising small amounts of carbyne in the lab, but it was thought to be extremely unstable. And some chemists have suggested that two strands coming into contact could react explosively.

“Our intention was to put it all together, to construct a complete mechanical picture of carbyne as a material,” said Vasilii Artyukhov, also from Rice University.

“The fact that it has been observed tells us it’s stable under tension, at least, because otherwise it would just fall apart.”

Mingjie Liu , Vasilii I. Artyukhov , Hoonkyung Lee ,Fangbo Xu , and Boris I. Yakobson, Carbyne From First Principles: Chain of C atoms, a Nanorod or a Nanorope,

ACS Nano,  DOI: 10.1021/nn404177r, October 5, 2013

Abstract: We report an extensive study of the properties of carbyne using first-principles calculations. We investigate carbyne’s mechanical response to tension, bending, and torsion deformations. Under tension, carbyne is about twice as stiff as the stiffest known materials and has an unrivaled specific strength of up to 7.5×10^7 N∙m/kg, requiring a force of ~10 nN to break a single atomic chain. Carbyne has a fairly large room-temperature persistence length of about 14 nm. Surprisingly, the torsional stiffness of carbyne can be zero but can be ‘switched on’ by appropriate functional groups at the ends. Further, under appropriate termination, carbyne can be switched into a magnetic-semiconductor state by mechanical twisting. We reconstruct the equivalent continuum-elasticity representation, providing the full set of elastic moduli for carbyne, showing its extreme mechanical performance (e.g. a nominal Young’s modulus of 32.7 TPa with an effective mechanical thickness of 0.772 Å). We also find an interesting coupling between strain and band gap of carbyne, which is strongly increased under tension, from 3.2 to 4.4 eV under a 10% strain. Finally, we study the performance of carbyne as a nanoscale electrical cable, and estimate its chemical stability against self-aggregation, finding an activation barrier of 0.6 eV for the carbyne–carbyne cross-linking reaction and an equilibrium cross-link density for two parallel carbyne chains of 1 cross-link per 17 C atoms (2.2 nm).

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From a sublime “Dreamliner” to the ridiculous

October 10, 2013

Nightmares (for Boeing) are made of this:

Reuters: Japan Airlines Co was forced to turn around its Tokyo-bound flight from Moscow on Thursday due to a problem in the Boeing 787 jet’s lavatory, a spokesman for the Japanese carrier said. … 

JAL spokesman Takuya Shimoguchi said the toilet malfunction on the flight from Moscow was likely caused by an electronic glitch. The airline was working on repairs on the ground, he added.

The flight, carrying 141 passengers, departed Moscow on Wednesday evening and returned after about five hours, he said.

Shares in JAL, which made headlines this week by signing with Boeing rival Airbus for the next generation of long-haul jets, were up 2.1 percent on Thursday morning, outperforming the broader market.

Updated 10th October:

BBC: 

Japan Airlines (JAL) says it has turned around two of its Boeing 787 Dreamliner aircraft during flights due to technical problems.

On one plane one of the two anti-ice systems, which prevent ice building up around the engine, failed.

Meanwhile, an electrical glitch made six toilets unusable on another flight.

These are the latest technical issues to hit the Dreamliner, which saw the entire fleet being grounded earlier this year following battery problems.

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Norwegian returns a Dreamliner to Boeing to be fixed

September 28, 2013

I suppose it must be under guarantee. It is further publicity that Boeing could well do without. Boeing have been asked to take back one of Norwegian’s two Dreamliners currently stuck in Bangkok with a hydraulic pump failure. Boeing will carry out the repairs in Stockholm. But what must be particularly galling for Boeing is that Norwegian is leasing an Airbus A340 while the Dreamliner is being fixed. No doubt the leasing cost will be billed to Boeing but EADS will be pleased that the Airbus has the better perception of reliability.

The Dreamliner runs the risk of becoming  a Nightmareliner if Boeing cannot get the plane away from its many “teething” troubles.

Boeing 787-8JP Dreamliner

Norwegians first Dreamliner Air Team Images : Photo by Lee A. Karas

Boeing 787-8JP Dreamliner

Manufacturer: Boeing   Type/Model: 787-8 Dreamliner   Registration: LN-BKA   Colour Scheme: Norwegian Air Shuttle
Location: Everett, United States  Taken By: Lee A. Karas   Date Taken: 3rd April 2013
Reuters: Budget airline Norwegian Air Shuttle  is returning one of its brand new Dreamliners to Boeing demanding repairs after the jet has suffered repeated breakdowns, it said on Saturday.Norwegian Air Shuttle will instead lease an Airbus A340 from HiFly to keep its long-haul business going and will not take back the Boeing 787 Dreamliner until it is more reliable, a spokesman said.“The aircraft’s reliability is simply not acceptable, our passengers cannot live with this kind of performance,” spokesman Lasse Sandaker-Nielsen told Reuters.“We are returning the aircraft to Boeing to improve its reliability.” ….Norwegian launched long-haul operations this year and hoped to capitalize on Dreamliner’s lower operating cost as the jet’s lighter-weight engines promised a 20 percent savings on fuel.

But its first two Dreamliners, part of a planned fleet of eight, broke down over half a dozen times in September, forcing it to lease back-up planes on short notice or cancel flights.

Norwegian summoned Boeing’s management this week and the aircraft manufacturer promised to locate spare parts centers at all of the airline’s long-haul destinations and send a team of engineers to the Nordics to monitor the planes.

The aircraft that will be returned is still stuck in Bangkok after a hydraulic pump failure this week and will be flown back to Stockholm where Boeing will carry out the work.

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2,000 year old thin film coating technology

July 25, 2013

Ancient gold and silversmiths used empirical methods with little knowledge of physics and chemistry to gild (silver and gold) statues and other works of art. It was an art – generally involving the use of mercury – which was also used by counterfeiters. Many of their techniques are still unknown. Some of the quality they achieved has still not been matched. A new paper is published in Accounts of Chemical Research (paywalled).

ACS Press Release: Gabriel Maria Ingo and colleagues point out that scientists have made good progress in understanding the chemistry of many ancient artistic and other artifacts — crucial to preserve them for future generations. Big gaps in knowledge remained, however, about how gilders in the Dark Ages and other periods applied such lustrous, impressively uniform films of gold or silver to intricate objects. Ingo’s team set out to apply the newest analytical techniques to uncover the ancients’ artistic secrets.

They discovered that gold- and silversmiths 2,000 years ago developed a variety of techniques, including using mercury like a glue to apply thin films of metals to statues and other objects. Sometimes, the technology was used to apply real gold and silver. It also was used fraudulently, to make cheap metal statues that look like solid gold or silver. The scientists say that their findings confirm “the high level of competence reached by the artists and craftsmen of these ancient periods who produced objects of an artistic quality that could not be bettered in ancient times and has not yet been reached in modern ones.

Gabriel Maria Ingo, Giuseppe Guida, Emma Angelini, Gabriella Di Carlo, Alessio Mezzi, Giuseppina Padeletti.Ancient Mercury-Based Plating Methods: Combined Use of Surface Analytical Techniques for the Study of Manufacturing Process and Degradation Phenomena. Accounts of Chemical Research, 2013; : 130705111206005 DOI: 10.1021/ar300232e

 

Abstract

Abstract Image

Fire gilding and silvering are age-old mercury-based processes used to coat thesurface of less precious substrates with thin layers of gold or silver. In ancient times, these methods were used to produce and decorate different types of artefacts, such as jewels, statues, amulets, and commonly-used objects. Gilders performed these processes not only to decorate objects but also to simulate the appearance of gold or silver, sometimes fraudulently. From a technological point of view, the aim of these workmen over 2000 years ago was to make the precious metal coatings as thin and adherent as possible. This was in order to save expensive metals and to improve the resistance to the wear caused by continued use and circulation.

Without knowledge about the chemical–physical processes, the ancient crafts-men systematically manipulated these metals to create functional and decorative artistic objects. The mercury-based methods were also fraudulently used in ancient times to produce objects such as jewels and coins that looked like they were made of silver or gold but actually had a less precious core. These coins were minted by counterfeiters but also by the official issuing authorities. The latter was probably because of a lack of precious metals, reflecting periods of severe economic conditions.

In this Account, we discuss some representative cases of gold- and silver-coatedobjects, focusing on unique and valuable Roman and Dark Ages period works of art, such as the St. Ambrogio’s altar (825 AD), and commonly used objects. We carried out the investigations using surface analytical methods, such as selected area X-ray photoelectron spectroscopy and scanning electron microscopy combined with energy-dispersive spectroscopy. We used these methods to investigate the surface and subsurface chemical features of these important examples of art and technology, interpreting some aspects of the manufacturing methods and of disclosing degradation agents and mechanisms. These findings may contribute to cultural heritage preservation, thus extending the applicability of the surface analytical techniques.

 

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Now “peak-copper”- like “peak oil” and “peak gas” – disappears from view

July 6, 2013

Following peak oil and peak gas  it now seems that “peak copper” is also disappearing over the horizon. Researchers at Monash University show that known copper reserves with existing recovery technologies are sufficient at least for 100 years and not just 30.

The fundamental fault with the alarmist image of resources running out – following a classic M. King Hubbert curve – is that alternatives to the resource and new discoveries of the resource are not taken into account. Added to this is the changes to consumption patterns that come about with changes of technology and with changes of price as a resource dwindles in availability. In fact it is the price change which itself acts a spur to the finding of alternatives and new technologies which do not even need that particular resource. “Peak” scenarios are a consequence of using numbers without the exercise of mind.

MU Press Release: New research shows that existing copper resources can sustain increasing world-wide demand for at least a century, meaning social and environmental concerns could be the most important restrictions on future copper production. 

Researchers from Monash University have conducted the most systematic and robust compilation and analysis of worldwide copper resources to date. Contrary to predictions estimating that supplies of this important metal would run out in around 30 years, the research has found there are plenty of resources within the reach of current technologies.

The database, published in two peer-reviewed papers, was compiled by Dr Gavin Mudd and Zhehan Weng from Environmental Engineering and Dr Simon Jowitt from the School of Geosciences. It is based on mineral resource estimates from mining companies and includes information vital for carbon and energy-use modelling, such as the ore grade of the deposits.

Dr Jowitt said the database could change the industry’s understanding of copper availability.

“Although our estimates are much larger than any previously available, they’re a minimum. In fact, figures for resources at some mining projects have already doubled or more since we completed the database,” Dr Jowitt said. 

“Further, the unprecedented level of detail we’ve presented will likely improve industry practice with respect to mineral resource reporting and allow more informed geological exploration.”

Dr Mudd said the vast volumes of available copper meant the mining picture was far more complex than merely stating there were ‘x’ years of supply left. …..

….. 

The researchers will now undertake detailed modelling of the life cycles and greenhouse gas impacts of potential copper production, and better assessment of future environmental impacts of mining.

They will also create similar databases for other metals, such as nickel, uranium, rare earths, cobalt and others, in order to paint a comprehensive picture of worldwide mineral availability.

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Argentina joins the shale gas bandwagon

April 8, 2013

The shale gas bandwagon is now truly rolling and countries all across the globe are scrambling to catch up. The wide-spread reserves mean that, more than any other energy source, shale gas has the potential of making concerns about energy security and reliance on foreign sources a thing of the past. South America also has its share of gas bearing shale. Argentina and Brazil have substantial shale deposits which the EIA estimates could give 774 and 226 trillion cubic feet of gas respectively. Even Chile and Bolivia have substantial deposits. The Argentinian deposits are only smaller than those in the US and China.

Shale Gas deposits South America SOURCE: USGS

Shale Gas deposits South America SOURCE: USGS

In April last year Argentina nationalised the YPF unit of Spanish Grupo Repsol which in turn had been acquired by Repsol on privatisation of YPF in 1999. There is a dispute ongoing between Repsol and the Argentinian government regarding the compensation for the nationalisation. One of the reasons for the nationalisation was a perceived reluctance from Repsol to invest in Argentina. While Repsol acquired YPF in 1999 for $15 billion, the nationalised assets of YPF are now valued at only around $9 billion.

OilPrice: Argentina shale gas reserves exceed its 13.4 trillion cubic feet (tcf) conventional proven gas reserves. The largest shale play is the Neuquen basin with more than 250 TCF. YPF discovered 4.5 TCF of shale gas in the Loma de la Lata Field of Neuquen in December 2010. Gas transportation and field services infrastructure are already in place making it attractive for further development. There are also additional Argentine shale deposit reserves in Chubut and Santa Cruz provinces near the Golfo San Jorge in the Atlantic southeast part of the country.  The U.S. Energy Information Administration (EIA) says Argentina’s technically recoverable shale gas reserves are the third largest in the world after the United States and China at 774 trillion cubic feet (Tcf) with more than half of that in the Neuquén Basin on the western side of the country. ….

To exploit its shale potential Argentina needs the active participation and assistance from large international oil field services companies and deep pocket investors. … Argentina’s shale resource potential is large enough to attract the biggest companies. But in the rapidly changing world of global shale development there are many places where investors can participate in the growth of shales without the risk Argentina presents. 

In any event Argentina is looking to make YPF a flagship for the country in the Oil & Gas space (with Petrobras across the border as an example to follow). And YPF will need both fracking technology and investment if they are to make something of their vast gas shale reserves in the Neuquén basin. There are a number of potential suitors from the US and even from China who may be prepared to take on the perceived country risks of Argentina, but Dow Chemical seems to be the first:

Chemical & Engineering News: With eyes on what could be the first shale gas project in Argentina, Dow Chemical has signed a memorandum of understanding with the Argentinian oil company YPF to develop a gas-rich area of the country.

The memorandum envisages YPF ceding Dow a 50% stake in a shale formation in Neuquén province. Dow and YPF also would explore expanding petrochemical capacity in the country on the basis of additional raw material supply. The firms are still negotiating the terms of the deal.

In the U.S., abundant shale-based feedstocks are leading to a renaissance in the petrochemical industry. According to the U.S. Energy Information Administration and consulting firm Advanced Resources International, Argentina has 774 trillion cu ft of recoverable shale gas reserves, the third-largest amount after the U.S. and China. But energy companies are so far only drilling exploratory wells in Argentina.

Dow already operates an ethylene cracker and polyethylene plants in Bahia Blanca, Argentina. In 2001, the company completed $720 million in expansion projects at the site.

And Dow is involved in chemical feedstocks in the country. In Bahia Blanca, it has a 28% interest in Compañía Mega, a natural gas liquids fractionation joint venture with YPF and Brazil’s Petrobras. The venture takes in natural gas liquids from Neuquén and supplies the ethane to Dow to feed its ethylene cracker.

The U.S. firm has been keen to expand its polyethylene business in the region but has been stymied by feedstock supply. Dow recently delayed a plant in Brazil that would get its ethylene from sugarcane-derived ethanol.

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Soyuz docks with ISS in record time

March 29, 2013

An update to my previous post.

Deutsche Welle:

A Soyuz capsule carrying three astronauts has docked at the International Space Station, just six hours after blasting off. Typically, manned Soyuz flights to the ISS last more than two days.

Russian cosmonauts Pavel Vinogradov and Alexander Misurkin and US astronaut Chris Cassidy took the express route to the International Space Station overnight Thursday, docking in the early hours of Friday morning.

They will join three other crew members and remain on board for five months.

“It’s such a beautiful sight, hard to believe my eyes,” the 59-year-old Vinogradov, making his third visit to space, said in footage broadcast on NASA TV.

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Lift-off today for 6 hour fast-track journey to the ISS

March 28, 2013

The International Space Station‘s orbit varies between altitudes of 330 – 410 km and it orbits the Earth about 15 times a day. So a journey taking 6 hours to scale about 70 km of altitude per hour may not seem so impressive compared to the speeds on a German autobahn. But a trip which used to be completed on the 3rd day and 34 orbits after lift-off is going to be covered in 5hrs 49 mins and 4 orbits after launch later today. For its 3-man crew, the Soyuz craft can only carry enough fuel and supplies for at most a 4 day journey, so this fast-track approach will represent a major saving of fuel and supplies.

Soyuz is the longest serving manned spacecraft...

Soyuz is the longest serving manned spacecraft design in history (1967– ) , upgraded regularly (Photo credit: Wikipedia)

From Space.com

(Following three unmanned, cargo-only test flights, the Expedition 35/36 crew is the first to try the technique. For the Soyuz crew of three, the fast track rendezvous is much the same as before, except that tasks are compressed.)

NASA astronaut Chris Cassidy and Russian cosmonauts Alexander Misurkin and Pavel Vinogradov are due to arrive at the orbiting laboratory just six hours after they launch at 4:43 p.m. EDT (2043 GMT). The liftoff will begin a months-long mission in orbit for the three men.

The trio will blast off from the Central Asian spaceport of Baikonur Cosmodrome in Kazakhstan aboard a Russian Soyuz spacecraft. The mission’s Soyuz rocket rolled out to the launch pad on Tuesday (March 26) to prepare for today’s liftoff.

In the nearly 13 years since crews first began launching to the International Space Station, it has taken Russian Soyuz capsules and U.S. space shuttles about two days to reach the orbiting lab after liftoff. Now, NASA and Russia’s Federal Space Agency are testing out a new, accelerated schedule. The quick journey, which takes just four orbits of Earth, has been carried out by recent unmanned cargo spacecraft visiting the space station, but never by a crew.

Cassidy, Misurkin and Vinogradov are planning to join the station’s Expedition 35 mission for a roughly six-month stay. The current residents of the outpost are commander Chris Hadfield of Canada, Russian cosmonaut Roman Romanenko, and NASA astronaut Tom Marshburn.

Infographic: How astronauts are traveling to the International Space Station in hours instead of days.

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Boeing’s three-layered fix for the Dreamliner batteries approved for testing

March 16, 2013

Boeing’s planned fix for the Dreamliner’s lithium-ion battery has been approved by the FAA and while this is only approval of the plan it at least represents the start of the process to get the Dreamliner back into the air. The FAA approval will allow two Dreamliners to return to the air to test various aspects of the proposed fix. Results from both in-flight and laboratory tests will have to be evaluated to obtain the new certifications and approvals necessary to get back into the air.

NY Times: The F.A.A. could still demand changes if problems develop in the laboratory and flight tests. While Boeing hopes to begin fitting its redesigned batteries in the grounded 787 fleet by mid- to late April and resume commercial flights quickly after that, government officials are not sure the process will move that fast. …

….. the tests would subject the battery to the most extreme conditions it was likely to face and determine if the case could withstand a battery explosion. The tests will include bursts of power to put stress on the battery and check its flammability as well as how it performs in hot weather.

The F.A.A. has also approved limited test flights for two aircraft. One plane will test the old battery, while the other will test how the new system performs under normal flight conditions. The flight tests will begin within a week.

The agency will approve the redesign only if the company successfully completes all required tests and analyses. The F.A.A. said it was continuing a review of the 787’s design, production and manufacturing.

But there is a downside. The fixes being introduced will increase the weight of the aircraft by 150 lbs which almost nullifies the advantage gained by using the lighter lithium-ion batteries in the first place. The fuel efficiency gains – at least those due to the lighter battery – will no longer be available and no doubt customers will want compensation for this. An extra 150 lbs is just about equivalent to one passenger and compensation claims could also be for the equivalent of one passenger less for every commercial flight through the life of the aircraft. This would be in addition to any compensation claims for losses suffered during and because of the grounding  and for delivery delays.

The three-layered approach that Boeing is taking consists of

  1. preventing a fire within any individual battery cell,
  2. preventing the fire from spreading to other cells in the event that a fire does occur, and
  3. preventing the fire from spreading or impacting anything outside the battery enclosure in the event that the fire does spread to multiple cells
Dreamliner Battery Fix (via Aviation Week, Credit Boeing)

Dreamliner Battery Fix (via Aviation Week, Credit Boeing)

The Dreamliner still has a way to go to complete all the testing and while Boeing is talking about “weeks rather than months”, it seems unlikely that the planes will be released for commercial flying before June.

Aviation Week: Among the tougher tests to be conducted will be an evaluation of the containment system’s ability to withstand a deliberately induced thermal runaway. This self-propagating phenomenon was cited by the National Transportation Safety Board (NTSB) in its March 7 interim report on the first battery failure on a Japan Airlines 787 in early January. Although not identifying a specific cause, the report described several shortcomings in both the baseline battery system design and the original means of testing and certification of the device.

The NTSB has announced plans to hold a forum and investigative hearing in April to review the battery’s technology, safety and process used in its certification. The agency’s investigation found—among other things—no record of the final production-standard charging system having been tested with the actual GS Yuasa-made battery. According to the NTSB report, Securiplane, the charging system developer, tested the unit with a simulated electric load instead of an actual battery. The company apparently took this precaution after having earlier suffered a fire at its facility during battery testing.

The three layers of the Boeing fix are structured as below:

1. The first layer of improvements is taking place during the manufacture of the batteries in Japan. Boeing teamed with Thales, the provider of the integrated power conversion system, and battery maker GS Yuasa to develop and institute enhanced production standards and tests to further reduce any possibility for variation in the production of the individual cells as well as the overall battery.  … Four new or revised tests have been added to screen cell production, which now includes 10 distinct tests. Each cell will go through more rigorous testing in the month following its manufacture including a 14-day test during which readings of discharge rates are being taken every hour. This new procedure started in early February and the first cells through the process are already complete. There are more than a dozen production acceptance tests that must be completed for each battery. Boeing, Thales and GS Yuasa have also decided to narrow the acceptable level of charge for the battery, both by lowering the highest charge allowed and raising the lower level allowed for discharge. Two pieces of equipment in the battery system – the battery monitoring unit and the charger are being redesigned to the narrower definition. The battery charger will also be adapted to soften the charging cycle to put less stress on the battery during charging.

2. Changes inside the battery will help to reduce the chances of a battery fault developing and help to further isolate any fault that does occur so that it won’t cause issues with other parts of the battery. To better insulate each of the cells in the battery from one another and from the battery box, two kinds of insulation will be added. An electrical insulator is being wrapped around each battery cell to electrically isolate cells from each other and from the battery case, even in the event of a failure. Electrical and thermal insulation installed above, below and between the cells will help keep the heat of the cells from impacting each other. Wire sleeving and the wiring inside the battery will be upgraded to be more resistant to heat and chafing and new fasteners will attach the metallic bars that connect the eight cells of the battery. These fasteners include a locking mechanism. Finally, a set of changes is being made to the battery case that contains the battery cells and the battery management unit. Small holes at the bottom will allow moisture to drain away from the battery and larger holes on the sides will allow a failed battery to vent with less impact to other parts of the battery.

3. The battery case will sit in a new enclosure made of stainless steel. This enclosure will isolate the battery from the rest of the equipment in the electronic equipment bays. It also will ensure there can be no fire inside the enclosure, thus adding another layer of protection to the battery system. The enclosure features a direct vent to carry battery vapors outside the airplane. New titanium fixtures are being installed in the electronics equipment bays to ensure the housing is properly supported. “Our first lines of improvements, the manufacturing tests and operations improvements, significantly reduce the likelihood of a battery failure. The second line of improvements, changes to the battery, helps stop an event and minimize the effect of a failure within the battery if it does occur. And the third line of improvements, the addition of the new enclosure, isolates the battery so that even if all the cells vent, there is no fire in the enclosure and there is no significant impact to the airplane,” said Sinnett.

Two aircraft will be used for the testing:

Flight tests of the prototype revised battery containment system will be conducted using Line No. 86, an aircraft designated for LOT Polish Airlines. Aviation Week was the first to report this same aircraft being previously used for ground tests of the battery system in mid-February (AW&ST Feb. 18, p. 32). The modified battery has also been installed in test aircraft ZA005, though Boeing says this is to allow testing to resume of the planned General Electric GEnx performance improvement package (PIP) II engine upgrade. The FAA says flight tests will validate instrumentation for the battery and testing its enclosure in addition to improvements for other systems.

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Water in the Earth’s interior

March 14, 2013

Phase diagram for water substance. image – craigssenseofwonder.wordpress.com

Water at supercritical conditions is a strange beast and has some remarkable chemistry. It is a fluid with properties that are a blend of gas and liquid properties. Steam at supercritical conditions (around 220 – 250 bar and about 600 °C)  is in common use in large power plants since it can be expanded in steam turbines for power generation. It has gas-like properties such that – as an Oxygen carrier – it could even support combustion/oxidation processes. It has liquid like properties and can be used as a solvent.

It would seem that if water is contained in the interior of the earth’s crust it could be at pressures above 22 MPa (220 bar) and temperatures above 374°C, beyond the critical point, and its properties as a very aggressive solvent  could be controlling the behavior of magma. So perhaps plate tectonics is all down to water?

I am a little skeptical since I observe – in passing – that the behaviour of supercritical steam does not seem to dissolve away steam turbine blades or casings when used in power generation!

A new paper on the 

Microscopic structure of water at elevated pressures and temperatures  by C. J. Sahle, C. Sternemann, C. Schmidt, S. Lehtola, S. Jahn, L. Simonelli, S. Huotari, M. Hakala, T. Pylkkanen, A. Nyrow, K. Mende, M. Tolan, K. Hamalainen and M. Wilke.

 Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1220301110

From the press release from the Helmholtz Centre, Potsdam

13.03.2013 | Potsdam: Earth is the only known planet that holds water in massive quantities and in all three phase states. But the earthly, omnipresent compound water has very unusual properties that become particularly evident when subjected to high pressure and high temperatures. In the latest issue of the Proceedings of the National Academy of Science (PNAS), a German-Finnish-French team published what happens when water is subjected to pressure and temperature conditions such as those found in the deep Earth. At pressures above 22 MPa and temperatures above 374°C, beyond the critical point, water turns into a very aggressive solvent, a fact that is crucial for the physical chemistry of Earth’s mantle and crust.

“Without water in Earth’s interior there would be no material cycles and no tectonics. But how the water affects processes in the upper mantle and crust is still subject of intense research”, said Dr. Max Wilke from the GFZ German Research Centre for Geosciences, who carried out the experiments along with his colleague Dr. Christian Schmidt and a team from the TU Dortmund. To this end, the research team brought the water to the laboratory. First, the microscopic structure of water as a function of pressure and temperature was studied by means of X-ray Raman scattering. For that purpose, diamond anvil cells of the GFZ were used at the European Synchrotron Radiation Facility ESRF in Grenoble. Inside the cell, a very small sample of water samples was enclosed, heated and brought to high temperatures and pressures. The data analysis was based on molecular dynamics simulations by the GFZ scientist Dr. Sandro Jahn.

“The study shows that the structure of water continuously develops from an ordered, polymerized structure to a disordered, marginally polymerized structure at supercritical conditions,” explains Max Wilke. “The knowledge of these structural properties of water in the deep earth is an important basis for the understanding of chemical distribution processes during metamorphic and magmatic processes.” This study provides an improved estimate of the behavior of water under extreme conditions during geochemical and geological processes. It is believed that the unique properties of supercritical water also control the behavior of magma.

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