solar power curtain:

http://www.cnn.com/2008/TECH/science/07/01/solar.textiles/index.html

http://www.talk2myshirt.com/blog/archives/517

http://www.inhabitat.com/2008/06/12/solar-harvesting-textiles-energize-soft-house/

Shape Memory Polymers (SMPs) are polymeric materials which have the ability to return from a deformed state (temporary shape) to their original (permanent) shape induced by an external stimulus (trigger), such as e.g. temperature change.

Besides temperature change, as in the case of thermally activated SMPs, specific SMPs can also be triggered by an electric or magnetic field, light or a change in pH. As well as polymers in general, SMP also cover a wide property-range from stable to biodegradable, from soft to hard and from elastic to rigid depending on the structural units that constitute the SMP. SMP include thermoplastic and thermoset (covalently cross-linked) polymeric materials. Shape memory polymers differ from shape memory alloys by their glass transition or melting transition from a hard to a soft phase which is responsible for the shape memory effect. In shape memory alloys Martensitic/Austenitic transitions are responsible for the shape memory effect.

The most recent developments are triple shape memory materials which can store two shapes in memory.

Shape Memory Alloys in Airplanes Reduce Turbulence



Shape Memory Textiles
http://www.youtube.com/watch?v=HdRRy7hItgI

Shape Memory Alloy Mirror Module



Skorpions

This project aims to find an elegant and more effective solution that can realize a controlled flexible environment. The assembly represents an interactive structure with emergent properties

The material system consists of components (from spirals of SMA) that affect each other. The SMA used in the project is a material consisting of three metals: nickel, titanium, copper (NiTiCu). Because of the characteristic of the alloy the deformation could be up to 5%. The material features two structures: the Hot shape and the Cold shape. The cold shape structure is very soft and could be deformed under load pressure whereas the hot shape determines the final position of the structure. The final result is coded to the SMA during the process of its production.
Components are assembled to create an electrical circuit in addition with lightweight conductive fibers. NiTiCu spirals serve as resistance wires. Therefore they are gradually heated. The stability is provided by lock joints and Teflon foil which serves against buckling of the whole assembly. Moreover, there is a variant with strong strings that hold the particles together. Physical representative models tested the pattern as well as possibilities for assembling the position and size of components. The proposed system opens a discussion regarding the division of environments and space. The structure could be used as an “intelligent” interior division or an environmentally sensitive shelter.

The design of the moving structure takes advantage of the Teflon foils and Shape Memory Alloys (SMAs) NiTiCu. This structure is fixed to the ground or to another structure and is a part of the electrical circuit. The reactions controlled by computer are caused by the various circuits which connect the members of spirals of SMAs. The members are covered by the layered Teflon foil which is welded to the shape which is determined by the critical shape of the whole structure.

The structure changes the shape continuously between the two critical positions. The SMAs change the shape according to the transformation temperature caused by the current passage. The deformation is about 5% but using spirals multiply the result. The transformation temperature is 30°C and that is why the spirals are covered with the heat protection covering. Two conditions of the structure come out from the characteristics of NiTiCu - the cold shape and the hot shape. The structure could be packed and transported during the cold shape position. The spirals of SMAs are welded to the joints which are connected by the system of locks which provides the stiffness of the whole structure. The structure is multilevel, and allotted chains determine the critical shape.

http://www.philipbeesleyarchitect.com/sculptures/0635hylozoic_soil/hylozoic_vid_01.html

http://www.philipbeesleyarchitect.com/sculptures/0635hylozoic_soil/hylozoic_vid_03.html

New solids discovered by physicists can strengthen materials, such as concrete, to protect buildings from earthquakes and severe weather.

Shape-memory alloys 'remember' the form of the structure they are built into, and will bend back to their original shape after being placed under stress. The researchers found that SMA wires embedded in concrete bars helped the concrete return to its original form after a load placed on the bar had caused it to crack and bend. However, the cracks in the concrete were left unsealed, reducing the strength and overall safety of the bars.

This problem was solved by using SMA wires in combination with repairing adhesives held inside hollow, brittle fibres, which snap under stress and fill any cracks with glue (pictured). The bars regained their original shape and strength after breaking. When they were reloaded, cracks appeared in other areas but were once again resealed.

Further research is required to investigate how to arrange the wires and adhesive fibres to ensure the technology is used effectively in large-scale construction projects.

The basic concept is the capability of transforming the shape of the passenger seats, by using futuristic flexible shape memory materials.
The same concept of flexibility applies to the general layout of the vehicle, whose wheelbase can be extended in order to carry large packages or shortened to allow for easy parking.
The vehicle structure consists of two cylinders that house the mechanical components and accumulators, while the powertrain adopts in-wheel electric motors.
The central console features a joystick command that can allow for both right-hand and left-hand drive.

Here is an good example of the application of SMA.

ORICALCO -- shape memory fabric

Grado Zero Espace (http://www.gzespace.com/gzenew/index.php?pg=consultants&lang=en) has used Shape Memory Alloys to obtain a fabric used for the manufacturing of a shirt with long sleeves. The sleeves could be programmed to shorten immediately as the room temperature heats up. The shirt can be screwed up, pleated and creased, then, just by a flux of hot air (even a hairdryer), it can pop back automatically to its former shape. Later, the name "Oricalco" was associated to the fabric Oricalco obtained by Grado Zero Espace and used to manufacture the first shape memory shirt.

youtube: http://www.youtube.com/watch?v=_oGQz-eSIOQ



thinking of the skin and enclosure system of buildings, and the issue of sustainability. Maybe we could apply the SMA technology, together with other technology, to find the environmentally friendly skin system of architecture.

Flexible Solar Cells

Scientists develop solar cells with a twist
Mon Oct 6, 2008 3:42pm EDT By Julie Steenhuysen

CHICAGO (Reuters) - U.S. researchers have found a way to make efficient silicon-based solar cells that are flexible enough to be rolled around a pencil and transparent enough to be used to tint windows on buildings or cars.

The finding, reported on Sunday in the journal Nature Materials, offers a new way to process conventional silicon by slicing the brittle wafers into ultrathin bits and carefully transferring them onto a flexible surface. "We can make it thin enough that we can put it on plastic to make a rollable system. You can make it gray in the form of a film that could be added to architectural glass," said John Rogers of the University of Illinois at Urbana-Champaign, who led the research.
"It opens up spaces on the fronts of buildings as opportunities for solar energy," Rogers said in a telephone interview. Solar cells, which convert solar energy into electricity, are in high demand because of higher oil prices and concerns over climate change.

Many companies, including Japanese consumer electronics maker Sharp Corp and Germany's Q-Cells are making thin-film solar cells, but they typically are less efficient at converting solar energy into electricity than conventional cells.

Rogers said his technology uses conventional single crystal silicon. "It's robust. It's highly efficient. But in its current form, it's rigid and fragile," he said. Rogers' team uses a special etching method that slices chips off the surface of a bulk silicon wafer. The sliced chips are 10 to 100 times thinner than the wafer, and the size can be adapted to the application.
Once sliced, a device picks up the bits of silicon chips "like a rubber stamp" and transfers them to a new surface material, Rogers said.

"These silicon solar cells become like a solid ink pad for that rubber stamp. The surface of the wafers after we've done this slicing become almost like an inking pad," he said.

"We just print them down onto a target surface." The final step is to electrically connect these cells to get power out of them, he said.

Adding flexibility to the material would make the cells far easier to transport. Rogers envisions the material being "rolled up like a carpet and thrown on the truck."

He said the technology has been licensed to a startup company called Semprius Inc in Durham, North Carolina, which is in talks to license the technology.

"It's just a way to use thing we already know well," Rogers said.

(C:\Documents and Settings\Yen-Yu Lin\My Documents\Studio611\Scientists develop solar cells with a twist Reuters_com.mht)

History of shape memory alloys

The three main types of SMA are the copper-zinc-aluminum-nickel, copper-aluminium-nickel, and nickel-titanium (NiTi) alloys and the most commonly seen is the NiTi. The first reported steps towards the discovery of the shape memory effect were taken in the 1930s. According to Otsuka and Wayman A. Ölander discovered the pseudoelastic behavior of the Au-Cd alloy in 1932. Greninger & Mooradian observed the formation and disappearance of a martensitic phase by decreasing and increasing the temperature of a Cu-Zn alloy. The basic phenomenon of the memory effect governed by the thermoelastic behavior of the martensite phase was widely reported a decade later by Kurdjumov & Khandros and also by Chang & Read. In the early 1960s, Buehler and his co-workers at the U.S. Naval Ordnance Laboratory discovered the shape memory effect in an equiatomic alloy of nickel and titanium, which can be considered a breaktrought in the field of shape memory materials. This alloy was named Nitinol (Nickel-Titanium Naval Ordnance Laboratory). Since that time, intensive investigations have been made to elucidate the mechanics of its basic behavior. The use of NiTi is fascinating because of its superelasticity and shape memory effect, which are completely new properties compared to the conventional metal alloys.

General principles

NiTi shape memory metal alloy can exist in a two different temperature-dependent crystal structures (phases) called martensite (lower temperature) and austenite (higher temperature or parent phase). Several properties of austenite NiTi and martensite NiTi are notably different. When martensite NiTi is heated, it begins to change into austenite.
The temperature at which this phenomenon starts is called austenite start temperature (As). The temperature at which this phenomenon is complete is called austenite finish temperature (Af). When austenite NiTi is cooled, it begins to change onto martensite. The temperature at which this phenomenon starts is called martensite start temperature (Ms). The temperature at which martensite is again completely reverted is called martensite finish temperature (Mf).

Composition and metallurgical treatments have dramatic impacts on the above transition temperatures. From the point of view of practical applications, NiTi can have three different forms: martensite, stress-induced martensite (superelastic), and austenite. When the material is in its martensite form, it is soft and ductile and can be easily deformed (somewhat like soft pewter). Superelastic NiTi is highly elastic (rubber-like), while austenitic NiTi is quite strong and hard (similar to titanium). The NiTi material has all these properties, their specific expression depending on the temperature in which it is used.


Shape memory effect

NiTi senses a change in ambient temperature and is able to convert its shape to a preprogrammed structure. While NiTi is soft and easily deformable in its lower temperature form (martensite), it resumes its original shape and rigidity when heated to its higher temperature form (austenite). This is called the one-way shape memory effect. The ability of shape memory alloys to recover a preset shape upon heating above the transformation temperatures and to return to a certain alternate shape upon cooling is known as the two-way shape memory effect.

Superelasticity

Superelasticity (or pseudoelasticity) refers to the ability of NiTi to return to its original shape upon unloading after a substantial deformation. This is based on stress-induced martensite formation. The macroscopic deformation is accommodated by the formation of martensite. When the stress is released, the martensite transforms back into austenite and the specimen returns back to its original shape. Superelastic NiTi can be strained several times more than ordinary metal alloys without being plastically deformed, which reflects its rubber-like behavior. It is, however, only observed over a specific temperature area.

Mechanical properties of NiTi

The mechanical properties of NiTi depend on its phase state at a certain temperature. NiTi has an ability to be highly damping and vibration-attenuating below As. For example, when a martensic NiTi ball is dropped from a constant height, it bounces only slightly over half the height reached by a similar ball dropped above the austenite temperature. NiTi has unique high fatigue and ductile properties, which are also related to its martensitic transformation. Also, very high wear resistance has been reported compared to the CoCrMo alloy. NiTi is a non-magnetic alloy. Electrical resistance and acoustic damping also change when the temperature changes.