Creating materials that copy the camouflage ability of an Octopus has long been a widely researched ability. This type of technology naturally has major advantages in military technology but could also eventually lead to the production of large, flexible display screens and anti-fouling coatings for ships. The challenges are many but researchers are getting closer to this goal as we speak. The following MIT News article sheds more light on this topic (Video included at the end of the article):
How to hide like an Octopus
Researchers create materials that reproduce cephalopods’ ability to quickly change colors and textures.
David L. Chandler | MIT News Office
September 16, 2014
Cephalopods, which include octopuses, squid, and cuttlefish, are among nature’s most skillful camouflage artists, able to change both the color and texture of their skin within seconds to blend into their surroundings — a capability that engineers have long struggled to duplicate in synthetic materials. Now a team of researchers has come closer than ever to achieving that goal, creating a flexible material that can change its color or fluorescence and its texture at the same time, on demand, by remote control.
The results of their research have been published in the journal Nature Communications, in a paper by a team led by MIT Assistant Professor of Mechanical Engineering Xuanhe Zhao and Duke University Professor of Chemistry Stephen Craig.
Zhao, who joined the MIT faculty from Duke this month and holds a joint appointment with the Department of Civil and Environmental Engineering, says the new material is essentially a layer of electro-active elastomer that could be quite easily adapted to standard manufacturing processes and uses readily available materials. This could make it a more economical dynamic camouflage material than others that are assembled from individually manufactured electronic modules.
While its most immediate applications are likely to be military, Zhao says the same basic approach could eventually lead to production of large, flexible display screens and anti-fouling coatings for ships.
In its initial proof-of-concept demonstrations, the material can be configured to respond with changes in both texture and fluorescence, or texture and color. In addition, while the present version can produce a limited range of colors, there is no reason that the range of the palette cannot be increased, Craig says.
Learning from nature
Cephalopods achieve their remarkable color changes using muscles that can alter the shapes of tiny pigment sacs within the skin — for example, contracting to change a barely visible round blob of color into a wide, flattened shape that is clearly seen. “In a relaxed state, it is very small,” Zhao says, but when the muscles contract, “they stretch that ball into a pancake, and use that to change color. The muscle contraction also varies skin textures, for example, from smooth to bumpy.” Octopuses use this mechanism both for camouflage and for signaling, he says, adding, “We got inspired by this idea, from this wonderful creature.”
The new synthetic material is a form of elastomer, a flexible, stretchable polymer. “It changes its fluorescence and texture together, in response to a change in voltage applied to it — essentially, changing at the flip of a switch,” says Qiming Wang, an MIT postdoc and the first author of the paper.
Researchers create materials that reproduce cephalopods’ ability to quickly change colors and textures
“We harnessed a physical phenomenon that we discovered in 2011, that applying voltage can dynamically change surface textures of elastomers,” Zhao says.
“The texturing and deformation of the elastomer further activates special mechanically responsive molecules embedded in the elastomer, which causes it to fluoresce or change color in response to voltage changes,” Craig adds. “Once you release the voltage, both the elastomer and the molecules return to their relaxed state — like the cephalopod skin with muscles relaxed.”
Multiple uses for quick changes
While troops and vehicles often move from one environment to another, they are presently limited to fixed camouflage patterns that might be effective in one environment but stick out like a sore thumb in another. Using a system like this new elastomer, Zhao suggests, either on uniforms or on vehicles, could allow the camouflage patterns to constantly change in response to the surroundings.
“The U.S. military spends millions developing different kinds of camouflage patterns, but they are all static,” Zhao says. “Modern warfare requires troops to deploy in many different environments during single missions. This system could potentially allow dynamic camouflage in different environments.”
Another important potential application, Zhao says, is for an anti-fouling coating on the hulls of ships, where microbes and creatures such as barnacles can accumulate and significantly degrade the efficiency of the ship’s propulsion. Earlier experiments have shown that even a brief change in the surface texture, from the smooth surface needed for fast movement to a rough, bumpy texture, can quickly remove more than 90 percent of the biological fouling.
Zhenan Bao, a professor of chemical engineering at Stanford University who was not involved in this research, says this is “inspiring work” and a “clever idea.” She adds, “I think the significant part is to combine the ability of mechanochemical response with electrical addressing so that they can induce fluorescence patterns by demand, reversibly.” Bao cautions that the researchers still face one significant challenge: “Currently they can only induce one kind of pattern in each type of material. It will be important to be able to change the patterns.”
In addition to Zhao, Craig, and Wang, the team also included Duke student Gregory Grossweiler. The work was supported by the U.S. Office of Naval Research, the U.S. Army Research Laboratory and Army Research Office, and the National Science Foundation.
A video on this topic:
Coal-to-liquid fuels poised for a comeback
With rising energy prices, could coal-to-liquid conversion become an economical fuel option?
Converting coal into liquid fuels is known to be more costly than current energy technologies, both in terms of production costs and the amount of greenhouse gases the process emits. Production of coal-to-liquid fuel, or CTL, has a large carbon footprint, releasing more than twice the lifecycle greenhouse gases of conventional petroleum fuels. However, with the rise in energy prices that began in 2008 and concerns over energy security, there is renewed interest in the conversion technology.
Researchers from the MIT Joint Program on the Science and Policy of Global Change (JPSPGC) recently released an assessment of the economic viability of CTL conversion. The researchers looked at how different climate policies and the availability of other fuel alternatives, such as biofuels, would influence the prospects of CTL in the future.
Coal-to-liquid technology has been in existence since the 1920s and was used extensively in Germany in 1944, producing around 90 percent of the national fuel needs at that time. Since then, the technology has been largely abandoned for the relatively cheaper crude oil of the Middle East. A notable exception is South Africa, where CTL conversion still provides about 30 percent of national transportation fuel.
But will there be a resurgence of CTL technology? To determine the role that CTL conversion would play in the future global fuel mix, researchers examined several crucial factors affecting CTL prospects. Different scenarios were modeled, varying the stringency of future carbon policies, the availability of biofuels and the ability to trade carbon allowances on an international market. Researchers also examined whether CTL-conversion plants would use carbon capture and storage technology, which would lower greenhouse gas emissions but create an added cost.
The study found that, without climate policy, CTL might become economical as early as 2015 in coal-abundant countries like the United States and China. In other regions, CTL could become economical by 2020 or 2025. Carbon capture and storage technologies would not be used, as they would raise costs. In this scenario, CTL has the potential to account for about a third of the global liquid-fuel supply by 2050.
However, the viability of CTL would be highly limited in regions that adopt climate policies, especially if low-carbon biofuels are available. Under scenarios that include stringent future climate policies, the high costs associated with a large carbon footprint would diminish CTL prospects, even with carbon capture and storage technologies. CTL conversion may only be viable in countries with less stringent climate policies or where low-carbon fuel alternatives are not available.
“In short, various climate proposals have very different impacts on the allowances of regional CO2 emissions, which in turn have quite distinct implications on the prospects for CTL conversion,” says John Reilly, co-director of the JPSPGC and one of the study’s authors. “If climate policies are enforced, world demand for petroleum products would decrease, the price of crude oil would fall, and coal-to-liquid fuels would be much less competitive.”
By Allison Crimmins | Joint Program on the Science and Policy of Global Change
June 9, 2011 as written on MIT Edu News
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Offshore drilling refers to a mechanical process where a wellbore is drilled through the seabed. It is typically carried out in order to explore for and subsequently extract petroleum which lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.
Offshore drilling presents environmental challenges, both from the produced hydrocarbons and the materials used during the drilling operation. Controversies include the ongoing US offshore drilling debate.
There are many different types of facilities from which offshore drilling operations take place. These include bottom founded drilling rigs (jackup barges and swamp barges), combined drilling and production facilities either bottom founded or floating platforms, and deepwater mobile offshore drilling units (MODU) including semi-submersibles and drillships. These are capable of operating in water depths up to 3,000 metres (9,800 ft). In shallower waters the mobile units are anchored to the seabed, however in deeper water (more than 1,500 metres (4,900 ft) the semisubmersibles or drillships are maintained at the required drilling location using dynamic positioning.
Around 1891, the first submerged oil wells were drilled from platforms built on piles in the fresh waters of the Grand Lake St. Marys (a.k.a. Mercer County Reservoir) in Ohio. The wells were developed by small local companies such as Bryson, Riley Oil, German-American and Banker’s Oil.
Around 1896, the first submerged oil wells in salt water were drilled in the portion of the Summerland field extending under the Santa Barbara Channel in California. The wells were drilled from piers extending from land out into the channel.
Other notable early submerged drilling activities occurred on the Canadian side of Lake Erie in the 1900s and Caddo Lake in Louisiana in the 1910s. Shortly thereafter wells were drilled in tidal zones along the Texas and Louisiana gulf coast. The Goose Creek Oil Field near Baytown, Texas is one such example. In the 1920s drilling activities occurred from concrete platforms in Venezuela‘s Lake Maracaibo.
One of the oldest subsea wells is the Bibi Eibat well, which came on stream in 1923 in Azerbaijan. The well was located on an artificial island in a shallow portion of the Caspian Sea. In the early 1930s, the Texas Co., later Texaco (now Chevron) developed the first mobile steel barges for drilling in the brackish coastal areas of the Gulf of Mexico.
In 1937, Pure Oil (now Chevron) and its partner Superior Oil (now ExxonMobil) used a fixed platform to develop a field 1 mile (1.6 km) offshore of Calcasieu Parish, Louisiana in 14 feet (4.3 m) of water.
In early 1947, Superior Oil erected a drilling and production platform in 20 feet (6.1 m) of water some 18 miles (29 km) off Vermilion Parish, La. But it was Kerr-McGee Oil Industries (now Anadarko Petroleum), as operator for partners Phillips Petroleum (ConocoPhillips) and Stanolind Oil & Gas (BP) that completed its historic Ship Shoal Block 32 well in October 1947, months before Superior actually drilled a discovery from their Vermilion platform farther offshore. In any case, that made Kerr-McGee’s well the first oil discovery drilled out of sight of land.
When offshore drilling moved into deeper waters of up to 30 metres (98 ft), fixed platform rigs were built, until demands for drilling equipment was needed in the 100 feet (30 m) to 120 metres (390 ft) depth of the Gulf of Mexico, the first jack-up rigs began appearing from specialized offshore drilling contractors such as forerunners of ENSCO International.
The first semi-submersible resulted from an unexpected observation in 1961. Blue Water Drilling Company owned and operated the four-column submersible Blue Water Rig No.1 in the Gulf of Mexico for Shell Oil Company. As the pontoons were not sufficiently buoyant to support the weight of the rig and its consumables, it was towed between locations at a draught mid-way between the top of the pontoons and the underside of the deck. It was noticed that the motions at this draught were very small, and Blue Water Drilling and Shell jointly decided to try operating the rig in the floating mode. The concept of an anchored, stable floating deep-sea platform had been designed and tested back in the 1920s by Edward Robert Armstrong for the purpose of operating aircraft with an invention known as the ‘seadrome’. The first purpose-built drilling semi-submersible Ocean Driller was launched in 1963. Since then, many semi-submersibles have been purpose-designed for the drilling industry mobile offshore fleet.
As of June, 2010, there were over 620 mobile offshore drilling rigs (Jackups, semisubs, drillships, barges) available for service in the competitive rig fleet.
One of the world’s deepest hubs is currently the Perdido in the Gulf of Mexico, floating in 2,438 meters of water. It is operated by Royal Dutch Shell and was built at a cost of $3 billion. The deepest operational platform is the Petrobras America Cascade FPSO in the Walker Ridge 249 field in 2,600 meters of water.
Main offshore fields
Notable offshore fields include:
- – the North Sea
- – the Gulf of Mexico (offshore Texas, Louisiana, Mississippi and Alabama)
- – California (in the Los Angeles Basin and Santa Barbara Channel, part of the Ventura Basin)
- – the Caspian Sea (notably some major fields offshore Azerbaijan)
- – the Campos and Santos Basins off the coasts of Brazil
- – Newfoundland and Nova Scotia (Atlantic Canada)
- – several fields off West Africa most notably west of Nigeria and Angola
- – offshore fields in South East Asia and Sakhalin, Russia
- – major offshore oil fields are located in the Persian Gulf such as Safaniya, Manifa and Marjan which belong to Saudi Arabia and are developed by Saudi Aramco.
- – fields in India (Mumbai High, K G Basin-East Coast Of India, Tapti Field Gujrat, India)
Offshore oil and gas production is more challenging than land-based installations due to the remote and harsher environment. Much of the innovation in the offshore petroleum sector concerns overcoming these challenges, including the need to provide very large production facilities. Production and drilling facilities may be very large and a large investment, such as the Troll A platform standing on a depth of 300 meters.
Another type of offshore platform may float with a mooring system to maintain it on location. While a floating system may be lower cost in deeper waters than a fixed platform, the dynamic nature of the platforms introduces many challenges for the drilling and production facilities.
The ocean can add several hundred meters or more to the fluid column. The addition increases the equivalent circulating density and downhole pressures in drilling wells, as well as the energy needed to lift produced fluids for separation on the platform.
The trend today is to conduct more of the production operations subsea, by separating water from oil and re-injecting it rather than pumping it up to a platform, or by flowing to onshore, with no installations visible above the sea. Subsea installations help to exploit resources at progressively deeper waters—locations which had been inaccessible—and overcome challenges posed by sea ice such as in the Barents Sea. One such challenge in shallower environments is seabed gouging by drifting ice features (means of protecting offshore installations against ice action includes burial in the seabed).
Offshore manned facilities also present logistics and human resources challenges. An offshore oil platform is a small community in itself with cafeteria, sleeping quarters, management and other support functions. In the North Sea, staff members are transported by helicopter for a two-week shift. They usually receive higher salary than onshore workers do. Supplies and waste are transported by ship, and the supply deliveries need to be carefully planned because storage space on the platform is limited. Today, much effort goes into relocating as many of the personnel as possible onshore, where management and technical experts are in touch with the platform by video conferencing. An onshore job is also more attractive for the aging workforce in the petroleum industry, at least in the western world. These efforts among others are contained in the established term integrated operations. The increased use of subsea facilities helps achieve the objective of keeping more workers onshore. Subsea facilities are also easier to expand, with new separators or different modules for different oil types, and are not limited by the fixed floor space of an above-water installation.
Engenya GmbH offers Mechanical And Computational Engineering Services in support of On and Offshore Drilling operations in both the DHA, Down Hole Assembly and out of the well. We have excelled in tool analysis, design, tool-string testing, vibration and shock testing, blast-loads and all facets of well completions and tool-strings.
The above article is adapted from Wikipedia under the Creative Commons Attribution-ShareAlike License