Preprint from the Alhemist

http://www.chemweb.com/alchem/articles/1035208921368.html

The SPHERical Approach to Weathering
26 November 2002
 

 

Walk into a big home improvement store in Alabama, Alaska or Arizona and pick up some indoor–outdoor carpeting and vinyl siding for your house. You, the store and the manufacturers all expect them to last years in the sun, but how can such polymer materials be tested in a accurate, reproducible way — so that both will survive in hot and wet, cold and wet, and hot and dry climates, each exposed to a slightly different UV spectrum? Asks Jonathan Beard.

For the last twenty years, the National Institute of Standards and Technology (NIST) has been working with industry and academics to come up with a better way of simulating weathering — and has found it in the shape of an 'integrating sphere'.

An integrating sphere

“UV testing chambers have come a long way since 1920.”

The sphere, an aluminum ball 2 meters in diameter, can reproduce almost any climate/radiation regime found in nature, and each of its 32 ports — where the samples are placed for testing — can be individually tailored, so the siding can be put in Alabama, Alaska and Arizona simultaneously.

Jonathan W. Martin, the group leader for the sphere at the NIST Building & Fire Research Lab in Maryland, says that UV testing chambers have come a long way since 1920. "Early chambers used lamps that heated specimens as hot as 60 °C, which is near the upper limit of exposure temperatures found in the natural environment: the surfaces of samples were not irradiated uniformly; and conditions varied over time during testing," he says. "In addition, most specimens were exposed to lots of radiation below 290 nm — a part of the spectrum that is filtered out by the atmosphere."

Simulating the right environment

“The temperature and relative humidity within an exposure chamber can be precisely set to the desired parameters.”

The integrating sphere is designed to avoid these problems. Six microwave-powered lamps are arranged around a port at the top of the sphere, but they do not directly illuminate the specimens. Dichroic mirrors reflect the light, subtracting much of the infrared and visible spectrum, and thus insuring that the base temperature does not rise above 30 °C — unless the manufacturer needs to test a material at higher or lower temperatures. In these cases, the temperature and relative humidity within an exposure chamber can be precisely set to the desired parameters.

“Acid rain and freeze-thaw environments can also be simulated.”

The interior of the sphere is lined with polytetrafluoroethylene (PTFE), a powder which reflects uniformly in every direction, so that each of the 32 sample chambers is bathed in uniform light. The high-intensity lamps are filtered to remove almost all of the radiation below 290 nm. In addition, because construction materials are often subject to mechanical loads in service, "we added that capability to each chamber," Martin says. Acid rain and freeze-thaw environments can also be simulated in the sphere.

Origins of the sphere

Where did the sphere come from? "In the late 1980s," Martin says, "we began developing a new methodology for testing polymeric materials used in construction and the automotive field. Similar techniques were already in use in the electronics, medical and nuclear industries, but they were new for construction materials. In 1994, two major coatings companies came to NIST and asked us to help create an industry–government–academic consortium to speed up the introduction of these methods for construction. We are now in our third 3-year phase of research, and the results have been so successful that we created a similar consortium with the sealants industry in 2001."

Corporations involved in the consortium have provided both financing and their own expertise, with additional input from universities and other government sources. "The Smithsonian Environmental Research Center, the Air Force, the Federal Highway Administration and other agencies have all collaborated with us," he says. Industry was interested in better testing methods, he adds, both to produce longer-lasting products and to reduce their liability when poorly performing products were sold. In addition, having the NIST test products with the sphere saves industry a lot of money. "Both suppliers and customers were often testing the same product, using different methods. Now both rely on the precision and lack of variability in our testing program."

Product lifetime

In the real world, a Dallas homeowner goes to a hardware store and asks: "If I paint my deck with this, how many years will it last?" NIST intends to deliver numbers. This research, Martin says, "will eventually result in quantitative estimates of the service life of polymeric materials in a given service environment. Such estimates are possible because each of the exposure variables is precisely controlled and the photodegradation response of an exposed material is quantitatively measured." In addition, his lab is trying "to identify the chemical and physical precursors of changes in the appearance of a product used by consumers in judging whether a product has failed."

“In practice, the SPHERE provides an embarrassment of quantitative riches.”
In practice, the SPHERE provides an embarrassment of quantitative riches. "It is designed to hold over 500 specimens, each in a unique exposure environment," Martin says, meaning too much data for traditional measurement and data processing procedures. Automation came to the rescue. "The specimens are now automatically analyzed, and the collected data analyzed on the fly using sophisticated software developed at NIST," he adds. Thus, almost immediately after the measurements have been made the current state of degradation of a specimen is known in addition to its degradation history.  

 

Smithsonian Environmental research center

http://www.serc.si.edu/

 

The Air force

http://www.af.mil/

The federal highways Administration

http://www.fhwa.dot.gov/

andd loop to the

trial

http://www.cnionline.com/

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Exxon Mobil gives $100m to Stanford-led Energy Project

21 November 2002

First published: 20-Nov-02 22:08 GMT
By Richard Knee, CNI

SAN FRANCISCO (CNI)--ExxonMobil will contribute nearly half the funding for a ten-year, $225m (€225m) research project to develop affordable energy sources that do not add carbon dioxide (CO2) to the atmosphere, the company said Wednesday.

ExxonMobil hopes the Stanford University-led effort, called the Global Climate and Energy Project (G-CEP) will produce ways "to very substantially reduce greenhouse gases" while providing economic growth and improving individuals lifestyles, especially in developing countries, said Frank Sprow, the company's vice president for safety, health and the environment.

Sprow's comments followed a public announcement of the project's launch at the university's campus in nearby Palo Alto, California.

Major investments, according to Stanford, will include $100m from ExxonMobil, $50m from General Electric (GE) and $25m from Schlumberger.

In addition, E.ON, Europe's largest privately owned energy service provider, has said it plans to contribute $50m and join G-CEP along with other academic and corporate sponsors from Europe, Stanford said.

The university said the total matches that for all corporate-sponsored research at Stanford during the past decade.

Lynn Orr, a professor of petroleum engineering, is stepping down as dean of Stanford's school of earth sciences to direct the project.

G-CEP's approach is to combine the faculty and student depth of Stanford and other universities with the research and commercial capabilities of the corporate sector to bring "new processes and products that will benefit our customers and society as a whole," Sprow said.

Stanford is especially strong in the biological- and computer-technology fields and the results of the research will be available to everyone, he said.

The project drew criticism from environmental and consumer groups concerned about the corporate-funding aspect.

Shannon Wright, coordinator of the Clean Energy Now campaign at Greenpeace, told CNI that ExxonMobil's involvement is a way of buying public relations while actually delaying progress toward an international agreement on greenhouse-gas reduction.

Sprow responded by noting that Stanford is heading G-CEP.

He emphasised the view that new energy sources and systems must prove not only effective but also affordable, particularly for developing countries.

Sprow said: "I don't recall any instance where governments or environmental groups have brought new products to the marketplace."

Putting the Sun into Syngas     15 November 2002

Australia, blessed with vast amounts of sunlight and adequate reserves of natural gas, has found a way to combine the two, creating a transportable fuel and reducing greenhouse gas emissions.

CSIRO, the government's research agency, working with Solar Systems Pty Ltd has built a reactor that sits on the solar collector and uses steam reforming of methane to produce syngas which can be further processed to produce hydrogen and carbon dioxide.

The solar dish used by CSIRO to create a new source of industrial energy for Australia from natural gas and sunlight. © CSIRO.
"This syngas produced on the solar dish contains around 26% more energy than the energy in the methane that you start off with," says Greg Duffy, the CSIRO Energy Technology Division project leader. "This extra energy is essentially stored solar energy."

 

The reactor sits at the centre of a tracking paraboloidal concentrating dish that collects the sun's energy to drive the reforming reactions. This reaction converts methane and water into carbon monoxide and hydrogen, adding 250 kJ of solar energy in the process.

"This syngas can be used as fuel or a chemical feed stock for producing methanol," Duffy says.

But a second stage makes it possible for carbon dioxide — a greenhouse gas — to be sequestered and removed. "You can further convert the carbon monoxide via a water gas shift reaction to carbon dioxide and more hydrogen. You then end up with a gas at pressure containing around 20% carbon dioxide and 80% hydrogen," Duffy says.

"The fact that the gas is at pressure facilitates the removal of the CO2."

Compared to burning methane itself — a common fuel for gas turbine power plants — the syngas releases about 20% less greenhouse gas per unit of energy, he adds, even without a way to bury or utilize the CO2, which would further increase the scheme's environmental attractiveness.

The dish now in operation uses 44 kW thermal of natural gas, but a full scale concentrator dish would handle 120 kW. Single dishes might be attractive for coal mines or waste dumps which generate small amounts of methane that is often wasted now. A big power plant would use multiple dishes or other types of solar collectors, Duffy says. 
Jonathan Beard

Industry — News in Brief            29 November 2002

Hungary's oil and gas group MOL increased its ownership of Slovakia's Slovnaft to 68%. MOL paid $85 million plus 9.99% of its shares for 31.6% of the Slovakian refinery.

MOL also submitted a bid for a stake in Poland's PKN Orlen and may bid to acquire partial ownership of Croatia's INA, Serbia's Beopetrol and the Czech Republic's Unipetrol. Meanwhile, MOL plans to invest $2 billion to improve plant profitability while reducing operating costs by $175 million by 2005. The cost cuts include a staff reduction of 2500 people.

A joint venture between China National Offshore Oil and Royal Dutch/Shell awarded construction contracts for a $4.3 billion petrochemical complex that will be China's largest.

JGC will receive $488 million to build an ethylene plant. Chiyoda, Mitsubishi and France's Technip will receive $325 million to construct a polymer plant and other facilities while Yokogawa Electric will receive $50 million to build a power plant. Construction at the Guangdong site will begin early next year.

PetroChina increased crude oil processing capacity at its Dalian refinery by nearly 25% to 205 500 barrels/day (bpd). Further expansion to 411 000 bpd in 2005 is planned to process oil imports from Siberia.

ExxonMobil restarted its 800 000 tonnes/year (tpy) Singapore steam cracker after an unplanned two-week closure due to a leak. The firm's force majeure on ethylene and propylene deliveries in Singapore will be cancelled after normal production resumes. Meanwhile, Taiwan's Chinese Petroleum restarted its 230 000-tpy Kaohsiung naphtha cracker after an unplanned shutdown due to a compressor problem.

Premcor purchased Williams Companies' Memphis, Tennessee refinery for $465 million. Nine other US refineries are for sale.

Four of Russia's five largest oil producers agreed to build an Arctic port that would enable Russia to provide 10% of US oil imports. Lukoil, Yukos, Tyumen Oil and Sibneft will spend $3.4–4.5 billion to build an ice-free deepwater oil port near Murmansk and an oil pipeline from western Siberia. A feasibility study won't be ready until 2003–2004.

Noranda expects its trouble-plagued new Magnola magnesium plant in Quebec to begin full commercial production in early 2003.

US regulators gave Schering-Plough permission to sell allergy medication Claritin without a prescription. This could result in lower prices for the popular antihistamine. Claritin's patent expires 19 December 2002. Schering-Plough plans to begin selling Claritin over-the-counter before generic versions from Wyeth Laboratories and Johnson & Johnson become available. The cheaper over-the-counter price could reduce sales of three prescription allergy medications: Schering-Plough's Clarinex, Aventis' Allegra and Pfizer's Zyrtec.

Denmark's Lundbeck has acquired US-based Synaptic Pharmaceutical for $121 million.

Exegenics and Innovative Drug Delivery Systems (IDDS) have terminated their planned merger. Exegenics is developing treatments for drug-resistant bacterial diseases while IDDS has three pain management drugs in various stages of development.

Biotechnology firm NeuroSearch and GlaxoSmithKline will jointly develop anti-depression drugs. The first milestone payment will be $27 million for any compound NeuroSearch discovers that GSK wants to buy and develop. Earlier this month NeuroSearch and Boehringer Ingelheim began development of a treatment for Alzheimer's disease.

Germany's Schering and Holland's Akzo Nobel will jointly develop a male birth control pill expected to become commercial in 5–7 years. The joint effort will begin by bringing a candidate to a Phase II clinical trial.

The final total price Novartis paid to acquire Slovenia's Lek was $877.8 million, the largest price ever paid for a generic drugmaker.  
John K. Borchardt

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