Carbon fiber reinforced polymer

Carbon fiber reinforced polymer, carbon fiber reinforced plastic, or carbon fiber reinforced thermoplastic (CFRP, CRP, CFRTP, or often simply carbon fiber, carbon composite, or even carbon), is an extremely strong and light fiber-reinforced plastic which contains carbon fibers. The alternative spelling 'fibre' is common in British Commonwealth countries. CFRPs can be expensive to produce but are commonly used wherever high strength-to-weight ratio and stiffness (rigidity) are required, such as aerospace, superstructure of ships, automotive, civil engineering, sports equipment, and an increasing number of consumer and technical applications.

The binding polymer is often a thermoset resin such as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The composite material may contain aramid (e.g. Kevlar, Twaron), ultra-high-molecular-weight polyethylene (UHMWPE), aluminium, or glass fibers in addition to carbon fibers. The properties of the final CFRP product can also be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used. The material is also referred to as graphite-reinforced polymer or graphite fiber-reinforced polymer (GFRP is less common, as it clashes with glass-(fiber)-reinforced polymer).

Cfk heli slw
Tail of a radio-controlled helicopter, made of CFRP

Properties

CFRPs are composite materials. In this case the composite consists of two parts: a matrix and a reinforcement. In CFRP the reinforcement is carbon fiber, which provides the strength. The matrix is usually a polymer resin, such as epoxy, to bind the reinforcements together.[1] Because CFRP consists of two distinct elements, the material properties depend on these two elements.

Reinforcement gives CFRP its strength and rigidity; measured by stress and elastic modulus respectively. Unlike isotropic materials like steel and aluminum, CFRP has directional strength properties. The properties of CFRP depend on the layouts of the carbon fiber and the proportion of the carbon fibers relative to the polymer.[2] The two different equations governing the net elastic modulus of composite materials using the properties of the carbon fibers and the polymer matrix can also be applied to carbon fiber reinforced plastics.[3] The following equation,

is valid for composite materials with the fibers oriented in the direction of the applied load. is the total composite modulus, and are the volume fractions of the matrix and fiber respectively in the composite, and and are the elastic moduli of the matrix and fibers respectively.[3] The other extreme case of the elastic modulus of the composite with the fibers oriented transverse to the applied load can be found using the following equation:[3]

The fracture toughness of carbon fiber reinforced plastics is governed by the following mechanisms: 1) debonding between the carbon fiber and polymer matrix, 2) fiber pull-out, and 3) delamination between the CFRP sheets.[4] Typical epoxy-based CFRPs exhibit virtually no plasticity, with less than 0.5% strain to failure. Although CFRPs with epoxy have high strength and elastic modulus, the brittle fracture mechanics present unique challenges to engineers in failure detection since failure occurs catastrophically.[4] As such, recent efforts to toughen CFRPs include modifying the existing epoxy material and finding alternative polymer matrix. One such material with high promise is PEEK, which exhibits an order of magnitude greater toughness with similar elastic modulus and tensile strength.[4] However, PEEK is much more difficult to process and more expensive.[4]

Despite its high initial strength-to-weight ratio, a design limitation of CFRP is its lack of a definable fatigue limit. This means, theoretically, that stress cycle failure cannot be ruled out. While steel and many other structural metals and alloys do have estimable fatigue or endurance limits, the complex failure modes of composites mean that the fatigue failure properties of CFRP are difficult to predict and design for. As a result, when using CFRP for critical cyclic-loading applications, engineers may need to design in considerable strength safety margins to provide suitable component reliability over its service life.

Environmental effects such as temperature and humidity can have profound effects on the polymer-based composites, including most CFRPs. While CFRPs demonstrate excellent corrosion resistance, the effect of moisture at wide ranges of temperatures can lead to degradation of the mechanical properties of CFRPs, particularly at the matrix-fiber interface.[5] While the carbon fibers themselves are not affected by the moisture diffusing into the material, the moisture plasticizes the polymer matrix.[4] The epoxy matrix used for engine fan blades is designed to be impervious against jet fuel, lubrication, and rain water, and external paint on the composites parts is applied to minimize damage from ultraviolet light.[4][6]

The carbon fibers can cause galvanic corrosion when CRP parts are attached to aluminum.[7]

Manufacture

Steinbichler Shearography Honeycomb with CFRP Top Layer Artificial failures that simulate layer- core delaminations Material Top view
Carbon fiber reinforced polymer

The primary element of CFRP is a carbon filament; this is produced from a precursor polymer such as polyacrylonitrile (PAN), rayon, or petroleum pitch. For synthetic polymers such as PAN or rayon, the precursor is first spun into filament yarns, using chemical and mechanical processes to initially align the polymer chains in a way to enhance the final physical properties of the completed carbon fiber. Precursor compositions and mechanical processes used during spinning filament yarns may vary among manufacturers. After drawing or spinning, the polymer filament yarns are then heated to drive off non-carbon atoms (carbonization), producing the final carbon fiber. The carbon fibers filament yarns may be further treated to improve handling qualities, then wound on to bobbins.[8] From these fibers, a unidirectional sheet is created. These sheets are layered onto each other in a quasi-isotropic layup, e.g. 0°, +60°, or −60° relative to each other.

From the elementary fiber, a bidirectional woven sheet can be created, i.e. a twill with a 2/2 weave. The process by which most CFRPs are made varies, depending on the piece being created, the finish (outside gloss) required, and how many of the piece will be produced. In addition, the choice of matrix can have a profound effect on the properties of the finished composite.

Many CFRP parts are created with a single layer of carbon fabric that is backed with fiberglass. A tool called a chopper gun is used to quickly create these composite parts. Once a thin shell is created out of carbon fiber, the chopper gun cuts rolls of fiberglass into short lengths and sprays resin at the same time, so that the fiberglass and resin are mixed on the spot. The resin is either external mix, wherein the hardener and resin are sprayed separately, or internal mixed, which requires cleaning after every use. Manufacturing methods may include the following:

Molding

One method of producing CFRP parts is by layering sheets of carbon fiber cloth into a mold in the shape of the final product. The alignment and weave of the cloth fibers is chosen to optimize the strength and stiffness properties of the resulting material. The mold is then filled with epoxy and is heated or air-cured. The resulting part is very corrosion-resistant, stiff, and strong for its weight. Parts used in less critical areas are manufactured by draping cloth over a mold, with epoxy either preimpregnated into the fibers (also known as pre-preg) or "painted" over it. High-performance parts using single molds are often vacuum-bagged and/or autoclave-cured, because even small air bubbles in the material will reduce strength. An alternative to the autoclave method is to use internal pressure via inflatable air bladders or EPS foam inside the non-cured laid-up carbon fiber.

Vacuum bagging

For simple pieces of which relatively few copies are needed (1–2 per day), a vacuum bag can be used. A fiberglass, carbon fiber, or aluminum mold is polished and waxed, and has a release agent applied before the fabric and resin are applied, and the vacuum is pulled and set aside to allow the piece to cure (harden). There are three ways to apply the resin to the fabric in a vacuum mold.

The first method is manual and called a wet layup, where the two-part resin is mixed and applied before being laid in the mold and placed in the bag. The other one is done by infusion, where the dry fabric and mold are placed inside the bag while the vacuum pulls the resin through a small tube into the bag, then through a tube with holes or something similar to evenly spread the resin throughout the fabric. Wire loom works perfectly for a tube that requires holes inside the bag. Both of these methods of applying resin require hand work to spread the resin evenly for a glossy finish with very small pin-holes.

A third method of constructing composite materials is known as a dry layup. Here, the carbon fiber material is already impregnated with resin (pre-preg) and is applied to the mold in a similar fashion to adhesive film. The assembly is then placed in a vacuum to cure. The dry layup method has the least amount of resin waste and can achieve lighter constructions than wet layup. Also, because larger amounts of resin are more difficult to bleed out with wet layup methods, pre-preg parts generally have fewer pinholes. Pinhole elimination with minimal resin amounts generally require the use of autoclave pressures to purge the residual gases out.

Compression molding

A quicker method uses a compression mold. This is a two-piece (male and female) mold usually made out of aluminum or steel that is pressed together with the fabric and resin between the two. The benefit is the speed of the entire process. Some car manufacturers, such as BMW, claimed to be able to cycle a new part every 80 seconds. However, this technique has a very high initial cost since the molds require CNC machining of very high precision.

Filament winding

For difficult or convoluted shapes, a filament winder can be used to make CFRP parts by winding filaments around a mandrel or a core.

Applications

Applications for CFRP include the following:

Aerospace engineering

F-WWCF A350 LBG SIAE 2015 (18953559366)
A composite Airbus A350 decorated in carbon fiber

The Airbus A350 XWB is built of 52% CFRP[9] including wing spars and fuselage components, overtaking the Boeing 787 Dreamliner, for the aircraft with the highest weight ratio for CFRP, which was held at 50%.[10] This was one of the first commercial aircraft to have wing spars made from composites. The Airbus A380 was one of the first commercial airliners to have a central wing-box made of CFRP; it is the first to have a smoothly contoured wing cross-section instead of the wings being partitioned span-wise into sections. This flowing, continuous cross section optimises aerodynamic efficiency.[11] Moreover, the trailing edge, along with the rear bulkhead, empennage, and un-pressurised fuselage are made of CFRP.[12] However, many delays have pushed order delivery dates back because of problems with the manufacture of these parts. Many aircraft that use CFRP have experienced delays with delivery dates due to the relatively new processes used to make CFRP components, whereas metallic structures have been studied and used on airframes for years, and the processes are relatively well understood. A recurrent problem is the monitoring of structural ageing, for which new methods are constantly investigated, due to the unusual multi-material and anisotropic nature of CFRP.[13]

In 1968 a Hyfil carbon-fiber fan assembly was in service on the Rolls-Royce Conways of the Vickers VC10s operated by BOAC.[14]

Specialist aircraft designers and manufacturers Scaled Composites have made extensive use of CFRP throughout their design range, including the first private manned spacecraft Spaceship One. CFRP is widely used in micro air vehicles (MAVs) because of its high strength to weight ratio.

SpaceX is using carbon fiber for the entire primary structure of their new super heavy-lift launch vehicle, the ITS launch vehicle—as well as the two very large spacecraft that will be launched by it, the Interplanetary Spaceship and the ITS tanker. This is a particular issue for the large liquid oxygen tank structure due to design challenges of such dense carbon/oxygen contact for long periods of time.[15][16]

Automotive engineering

Rétromobile 2011 - Citroën SM Rallye du Maroc 1971 - 003
Citroën SM that won 1971 Rally of Morocco with carbon fiber wheels
McLaren F1 in Geneva, Switzerland
1996 McLaren F1 – first carbon fiber body shell

CFRPs are extensively used in high-end automobile racing.[17] The high cost of carbon fiber is mitigated by the material's unsurpassed strength-to-weight ratio, and low weight is essential for high-performance automobile racing. Race-car manufacturers have also developed methods to give carbon fiber pieces strength in a certain direction, making it strong in a load-bearing direction, but weak in directions where little or no load would be placed on the member. Conversely, manufacturers developed omnidirectional carbon fiber weaves that apply strength in all directions. This type of carbon fiber assembly is most widely used in the "safety cell" monocoque chassis assembly of high-performance race-cars.

Many supercars over the past few decades have incorporated CFRP extensively in their manufacture, using it for their monocoque chassis as well as other components.[18] As far back as 1971, the Citroën SM offered optional lightweight carbon fiber wheels.[19][20]

Use of the material has been more readily adopted by low-volume manufacturers who used it primarily for creating body-panels for some of their high-end cars due to its increased strength and decreased weight compared with the glass-reinforced polymer they used for the majority of their products.

Civil engineering

CFRP has become a notable material in structural engineering applications. Studied in an academic context as to its potential benefits in construction, it has also proved itself cost-effective in a number of field applications strengthening concrete, masonry, steel, cast iron, and timber structures. Its use in industry can be either for retrofitting to strengthen an existing structure or as an alternative reinforcing (or pre-stressing) material instead of steel from the outset of a project.

Retrofitting has become the increasingly dominant use of the material in civil engineering, and applications include increasing the load capacity of old structures (such as bridges) that were designed to tolerate far lower service loads than they are experiencing today, seismic retrofitting, and repair of damaged structures. Retrofitting is popular in many instances as the cost of replacing the deficient structure can greatly exceed the cost of strengthening using CFRP.[21]

Applied to reinforced concrete structures for flexure, CFRP typically has a large impact on strength (doubling or more the strength of the section is not uncommon), but only a moderate increase in stiffness (perhaps a 10% increase). This is because the material used in this application is typically very strong (e.g., 3000 MPa ultimate tensile strength, more than 10 times mild steel) but not particularly stiff (150 to 250 GPa, a little less than steel, is typical). As a consequence, only small cross-sectional areas of the material are used. Small areas of very high strength but moderate stiffness material will significantly increase strength, but not stiffness.

CFRP can also be applied to enhance shear strength of reinforced concrete by wrapping fabrics or fibers around the section to be strengthened. Wrapping around sections (such as bridge or building columns) can also enhance the ductility of the section, greatly increasing the resistance to collapse under earthquake loading. Such 'seismic retrofit' is the major application in earthquake-prone areas, since it is much more economic than alternative methods.

If a column is circular (or nearly so) an increase in axial capacity is also achieved by wrapping. In this application, the confinement of the CFRP wrap enhances the compressive strength of the concrete. However, although large increases are achieved in the ultimate collapse load, the concrete will crack at only slightly enhanced load, meaning that this application is only occasionally used. Specialist ultra-high modulus CFRP (with tensile modulus of 420 GPa or more) is one of the few practical methods of strengthening cast-iron beams. In typical use, it is bonded to the tensile flange of the section, both increasing the stiffness of the section and lowering the neutral axis, thus greatly reducing the maximum tensile stress in the cast iron.

In the United States, pre-stressed concrete cylinder pipes (PCCP) account for a vast majority of water transmission mains. Due to their large diameters, failures of PCCP are usually catastrophic and affect large populations. Approximately 19,000 miles (31,000 km) of PCCP have been installed between 1940 and 2006. Corrosion in the form of hydrogen embrittlement has been blamed for the gradual deterioration of the pre-stressing wires in many PCCP lines. Over the past decade, CFRPs have been utilized to internally line PCCP, resulting in a fully structural strengthening system. Inside a PCCP line, the CFRP liner acts as a barrier that controls the level of strain experienced by the steel cylinder in the host pipe. The composite liner enables the steel cylinder to perform within its elastic range, to ensure the pipeline's long-term performance is maintained. CFRP liner designs are based on strain compatibility between the liner and host pipe.[22]

CFRP is a more costly material than its counterparts in the construction industry, glass fiber-reinforced polymer (GFRP) and aramid fiber-reinforced polymer (AFRP), though CFRP is, in general, regarded as having superior properties. Much research continues to be done on using CFRP both for retrofitting and as an alternative to steel as a reinforcing or pre-stressing material. Cost remains an issue and long-term durability questions still remain. Some are concerned about the brittle nature of CFRP, in contrast to the ductility of steel. Though design codes have been drawn up by institutions such as the American Concrete Institute, there remains some hesitation among the engineering community about implementing these alternative materials. In part, this is due to a lack of standardization and the proprietary nature of the fiber and resin combinations on the market.

Carbon-fiber microelectrodes

Carbon fibers are used for fabrication of carbon-fiber microelectrodes. In this application typically a single carbon fiber with diameter of 5–7 μm is sealed in a glass capillary.[23] At the tip the capillary is either sealed with epoxy and polished to make carbon-fiber disk microelectrode or the fiber is cut to a length of 75–150 μm to make carbon-fiber cylinder electrode. Carbon-fiber microelectrodes are used either in amperometry or fast-scan cyclic voltammetry for detection of biochemical signaling.

Sports goods

Carbon Fiber and Kevlar Canoe
A carbon-fiber and Kevlar canoe (Placid Boatworks Rapidfire at the Adirondack Canoe Classic)

CFRP is now widely used in sports equipment such as in squash, tennis, and badminton racquets, sport kite spars, high quality arrow shafts, hockey sticks, fishing rods, surfboards, high end swim fins, and rowing shells. Amputee athletes such as Jonnie Peacock use carbon fiber blades for running. It is used as a shank plate in some basketball sneakers to keep the foot stable, usually running the length of the shoe just above the sole and left exposed in some areas, usually in the arch.

Controversially, in 2006, cricket bats with a thin carbon-fiber layer on the back were introduced and used in competitive matches by high-profile players including Ricky Ponting and Michael Hussey. The carbon fiber was claimed merely to increase the durability of the bats but was banned from all first-class matches by the ICC in 2007.[24]

A CFRP bicycle frame weighs less than one of steel, aluminum, or titanium having the same strength. The type and orientation of the carbon-fiber weave can be designed to maximize stiffness in required directions. Frames can be tuned to address different riding styles: sprint events require stiffer frames while endurance events may require more flexible frames for rider comfort over longer periods.[25] The variety of shapes it can be built into has further increased stiffness and also allowed aerodynamic tube sections. CFRP forks including suspension fork crowns and steerers, handlebars, seatposts, and crank arms are becoming more common on medium as well as higher-priced bicycles. CFRP rims remain expensive but their stability compared to aluminium reduces the need to re-true a wheel and the reduced mass reduces the moment of inertia of the wheel. CFRP spokes are rare and most carbon wheelsets retain traditional stainless steel spokes. CFRP also appears increasingly in other components such as derailleur parts, brake and shifter levers and bodies, cassette sprocket carriers, suspension linkages, disc brake rotors, pedals, shoe soles, and saddle rails. Although strong and light, impact, over-torquing, or improper installation of CFRP components has resulted in cracking and failures, which may be difficult or impossible to repair.[26][27]

Other applications

The fire resistance of polymers and thermo-set composites is significantly improved if a thin layer of carbon fibers is moulded near the surface because a dense, compact layer of carbon fibers efficiently reflects heat.[28]

CFRP is also finding application in an increasing number of high-end products that require stiffness and low weight, these include:

  • Musical instruments, including violin bows, guitar picks and pick-guards, drum shells, bagpipe chanters, and entire musical instruments such as Luis and Clark's carbon fiber cellos, violas, and violins; and Blackbird Guitars' acoustic guitars and ukuleles; also audio components such as turntables and loudspeakers.
  • Firearms use it to replace certain metal, wood, and fiberglass components but many of the internal parts are still limited to metal alloys as current reinforced plastics are unsuitable.
  • High-performance drone bodies and other radio-controlled vehicle and aircraft components such as helicopter rotor blades.
  • Lightweight poles such as: tripod legs, tent poles, fishing rods, billiards cues, walking sticks, and high-reach poles such as for window cleaning.
  • Dentistry, carbon fiber posts are used in restoring root canal treated teeth.
  • Railed train bogies for passenger service. This reduces the weight by up to 50% compared to metal bogies, which contributes to energy savings.[29]
  • Laptop shells and other high performance cases.
  • Carbon woven fabrics.[30][31]
  • Archery, carbon fiber arrows and bolts, stock and rail.

Disposal and recycling

CFRPs have a long service lifetime when protected from the sun. When it is time to decommission CFRPs, they cannot be melted down in air like many metals. When free of vinyl (PVC or polyvinyl chloride) and other halogenated polymers, CFRPs can be thermally decomposed via thermal depolymerization in an oxygen-free environment. This can be accomplished in a refinery in a one-step process. Capture and reuse of the carbon and monomers is then possible. CFRPs can also be milled or shredded at low temperature to reclaim the carbon fiber; however, this process shortens the fibers dramatically. Just as with downcycled paper, the shortened fibers cause the recycled material to be weaker than the original material. There are still many industrial applications that do not need the strength of full-length carbon fiber reinforcement. For example, chopped reclaimed carbon fiber can be used in consumer electronics, such as laptops. It provides excellent reinforcement of the polymers used even if it lacks the strength-to-weight ratio of an aerospace component.

Carbon nanotube reinforced polymer (CNRP)

In 2009, Zyvex Technologies introduced carbon nanotube-reinforced epoxy and carbon pre-pregs.[32] Carbon nanotube reinforced polymer (CNRP) is several times stronger and tougher than CFRP and is used in the Lockheed Martin F-35 Lightning II as a structural material for aircraft.[33] CNRP still uses carbon fiber as the primary reinforcement, but the binding matrix is a carbon nanotube filled epoxy.[34]

See also

References

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  2. ^ Basic Properties of Reference Crossply Carbon-Fiber Composite Archived 19 June 2012 at the Wayback Machine. Oak Ridge National Laboratory (February 2000)
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  28. ^ Zhao, Z.; Gou, J. (2009). "Improved fire retardancy of thermoset composites modified with carbon nanofibers". Sci. Technol. Adv. Mater. 10 (1): 015005. Bibcode:2009STAdM..10a5005Z. doi:10.1088/1468-6996/10/1/015005. PMC 5109595. PMID 27877268.
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External links

ATEC v.o.s.

ATEC v.o.s. is a Czech aircraft manufacturer, founded in 1992 and based in Libice nad Cidlinou. The company specializes in the design and manufacture of ultralight aircraft in the form of kits for amateur construction as well as ready-to-fly aircraft for the European Fédération Aéronautique Internationale microlight and the American light-sport aircraft categories.Petr Volejník is the company owner, general and production manager, designer and test pilot.The company was formed in 1992 as a manufacturer of aircraft parts under sub-contract. The first aircraft built was the composite fuselage wood and fabric-wing Zephyr in 1996. The design was developed into the smaller, single-seat ATEC 212 Solo made entirely from carbon-fiber-reinforced polymer. The ATEC 321 Faeta was introduced in 2003 and improves on the Zephyr in that it is also made from carbon fibre.The Faeta has been accepted by the US Federal Aviation Administration as a light-sport aircraft.

Boeing Condor

The Boeing Condor is a high-tech test bed aerial reconnaissance unmanned aerial vehicle. It has a wingspan of over 200 feet.Carbon-fibre composite materials make up the bulk of the Condor's fuselage and wings. Although the Condor has a relatively low radar cross-section and infrared signature, it is not unobservable making it too vulnerable for use in military operations.The Condor is completely robotic, with an onboard computer to communicate with the computers on the ground via satellite to control all facets of the Condor's missions. The Condor's frame is made of mainly Carbon-fiber-reinforced polymer composite, as it gives off very low radar and heat signatures.In 1989, the Condor set the world piston-powered aircraft altitude record of 67,028 ft (20,430 m) and was the first aircraft to fly a fully automated flight from takeoff to landing and also setting an unofficial endurance world record in 1988 by flying continuously for more than 50 hours; the flight was not ratified by the Fédération Aéronautique Internationale (FAI) and is therefore not considered an official record.During its evaluations, the Condor logged over 300 flight hours, flying over Moses Lake, Washington.

CFK

CFK may refer to:

Carolina for Kibera

Chemische Fabrik Kalk, a former German chemical company

Chefornak Airport, Alaska, US, FAA LID code

Cristina Fernández de Kirchner, President of Argentina from 2007 to 2015

Carbonfaserverstärkte Kunststoffe (CFK or CFvK), which translates to carbon fiber reinforced polymer (CFRP)

Carbon fibers

Carbon fibers or carbon fibres (alternatively CF, graphite fiber or graphite fibre) are fibers about 5–10 micrometres in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion. These properties have made carbon fiber very popular in aerospace, civil engineering, military, and motorsports, along with other competition sports. However, they are relatively expensive when compared with similar fibers, such as glass fibers or plastic fibers.

To produce a carbon fiber, the carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber as the crystal alignment gives the fiber high strength-to-volume ratio (making it strong for its size). Several thousand carbon fibers are bundled together to form a tow, which may be used by itself or woven into a fabric.

Carbon fibers are usually combined with other materials to form a composite. When impregnated with a plastic resin and baked it forms carbon-fiber-reinforced polymer (often referred to as carbon fiber) which has a very high strength-to-weight ratio, and is extremely rigid although somewhat brittle. Carbon fibers are also composited with other materials, such as graphite, to form reinforced carbon-carbon composites, which have a very high heat tolerance.

Coxless four

A coxless four is a rowing boat used in the sport of competitive rowing. It is designed for four persons who propel the boat with sweep oars.

The crew consists of four rowers, each having one oar. There are two rowers on the stroke side (rower's right hand side) and two on the bow side (rower's lefthand side). There is no coxswain, but the rudder is controlled by one of the crew, normally with the rudder cable attached to the toe of one of their shoes which can pivot about the ball of the foot, moving the cable left or right. The steersman may row at bow, who has the best vision when looking over their shoulder, or on straighter courses stroke may steer, since they can point the stern of the boat at some landmark at the start of the course. The equivalent boat when it is steered by a coxswain is called a "coxed four".

Racing boats (often called "shells") are long, narrow, and broadly semi-circular in cross-section in order to reduce drag to a minimum. Originally made from wood, shells are now typically made from a composite material, usually carbon fiber reinforced polymer, for strength and weight advantages. Fours have a fin near the stern, to help prevent roll and yaw and to help the rudder. The riggers are staggered alternately along the boat so that the forces apply asymmetrically to each side of the boat. If the boat is sculled by rowers, each with two oars, the combination is called a quad scull. In a quad scull the riggers apply forces symmetrically. A sweep oared boat has to be stiffer to handle the unmatched forces, and so requires more bracing, which means it has to be heavier than an equivalent sculling boat. However most rowing clubs cannot afford to have a dedicated large hull with four seats, which might be rarely used and instead generally opt for versatility in their fleet by using stronger shells that can be rigged either as fours or quads.

"Coxless four" is one of the classes recognized by the International Rowing Federation and is an event at the Olympic Games.

In 1868, Walter Bradford Woodgate rowing a Brasenose coxed four arranged for his coxswain to jump overboard at the start of the Stewards' Challenge Cup at Henley Royal Regatta to lighten the boat. The unwanted cox narrowly escaped strangulation by the water lilies, but Woodgate and his homemade steering device triumphed by 100 yards and were promptly disqualified. This led to the adoption of Henley Regatta rules specifically prohibiting such conduct and a special prize for four-oared crews without coxswains was offered at the regatta in 1869. However in 1873 the Stewards cup was changed to a coxless four event.

EcoJet concept car

The EcoJet concept car is a concept car designed to run on biodiesel fuel, using a Honeywell LTS101 gas turbine instead of a reciprocating engine. The engine is normally used in helicopters and provides 650 horsepower and 583 ft-lb of torque. Drive is to the rear wheels through a four-speed automatic transaxle adapted from a C5 Corvette. An automatic transmission had to be used, because the turbine requires a constant load and operating a clutch with a manual gearbox would cause the turbine to overspeed.

This concept car was the result of a collaboration between Jay Leno and General Motors, Honeywell, Alcoa and BASF. Unlike other concept cars, it was meant to be driven on the road in a regular fashion, as well as for show purposes.

It is a two-seater car of a coupé design with a hydroformed aluminum chassis and carbon-fiber-reinforced polymer bodywork. The car contains two separate fuel tanks; one contains the main biodiesel fuel, soybean oil, and the other contains a conventional clean-burning jet engine fuel, Jet A (kerosene). The kerosene is used to start the turbine easily at the beginning of a trip and also to run the engine at the end of a trip to clean it, since biodiesel fuel tends to gum up the fuel system if not cleared. The exhaust gas temperature is 1000 degrees Fahrenheit in normal operation and 1800 Fahrenheit at full power. Exhaust is directed upward from two ports on the rear deck. In essence, the car runs on refined cooking oil, thus producing the same kind of smell created by cooking French fries.

The car has an Azentek in-dash car computer running Microsoft Windows Vista, with two LCD screens on the dashboard — one for the aircraft-style digital gauges and another for the multimedia and navigation controls — as well as the standard PC functions, such as word processing and Web access through a WiMAX system. Two other smaller LCD screens are placed on the dashboard to provide rear views, as the car has no rear-view mirrors and uses cameras instead. The functions are controlled by Touchscreen or by Speech recognition software, using an array of microphones. The car was assembled by the Big Dog crew, mechanics employed by Jay Leno to help him maintain his large collection of cars.

Epsilon composite

Epsilon Composite is a French company created in 1987 by Stephane LULL, its current CEO.

Turnover in 2012 was 21M€ with 190 employees.Epsilon Composite produces a wide range of Carbon-fiber-reinforced polymer (CFRP) products for various applications:

Manufacturing and printing machines (flexography and textile industries)

Energy (oil & gas offshore exploitation, wind turbines)

Civil Engineering

Camera support equipments (tripods)

Automotive and leisure applications

AerospaceThe main production process used by the company is pultrusion.

Epsilon Composite is mainly dealing with international customers (90% of the turnover comes from exports), mostly from Japan and Germany. The production site is located in Gaillan, France

Flex-Foot Cheetah

The Flex-Foot Cheetah is a prosthetic human foot replacement developed by biomedical engineer Van Phillips, who had lost a leg below the knee at age 21; the deficiencies of existing prostheses led him to invent this new prosthesis.

The Flex-Foot Cheetah and similar models are worn by Oscar Pistorius and other amputee athletes in the Paralympics and elsewhere. It is made from carbon fibre, and unlike all previous foot prostheses, it stores kinetic energy from the wearer's steps as potential energy, like a spring, allowing the wearer to run and jump. It is now (as of September 2012) made by Össur.Carbon fiber is actually a carbon-fiber-reinforced polymer, and is a strong, light-weight material used in a number of applications, including sporting goods like baseball bats, car parts, helmets, sailboats, bicycles and other equipment where rigidity and high strength-to-weight ratio is important. The polymer used for this equipment is normally epoxy, but other polymers are also used, depending on the application, and other reinforcing fibers may also be included. In the blade manufacturing process, sheets of impregnated material are cut into square sheets and pressed onto a form to produce the final shape. From 30 to 90 sheets may be layered, depending on the expected weight of the athlete, and the mold is then autoclaved to fuse the sheets into a solid plate. This method reduces air bubbles that can cause breaks. Once the result is cooled, it is cut into the shape of the blades, each of which costs between $15,000 and $18,000.About 90 percent of amputee Paralympics runners use a variation of the original Flex-Foot design, as well as thousands of athletes around the world. "Bladerunners" seen at the Paralympics who have lost both feet run in the T43 class, but runners with one blade and a natural foot run in the T44 class.

Grob Aircraft

Grob Aircraft is a German aircraft manufacturer, previously known as Grob Aerospace. It has been manufacturing aircraft using carbon fiber reinforced polymer since the 1970s.

Ivoprop

Ivoprop Corporation, founded in 1984 by Ivo Zdarsky, is an American manufacturer of composite propellers for homebuilt and ultralight aircraft, as well as airboats. The company's headquarters are in Long Beach, California.Zdarsky started the company after carving his own propeller for a homebuilt ultralight trike that he flew from Cold War Czechoslovakia, over the Iron Curtain to Vienna in 1984. Ivoprop has sold more than 20,000 propellers since then.The company's propellers are built from carbon-fiber-reinforced polymer and feature a stainless steel leading edge.

Mae West (sculpture)

Mae West is a sculpture in Munich-Bogenhausen designed by Rita McBride. Named after the actress, the plastic artwork is a 52 meter high hyperboloid of one sheet built from carbon fiber reinforced polymer.Mae West was planned in 2002 for the newly available Effnerplatz after construction of a tunnel. Following highly controversial discussions about size, shape and cost both within the city council and among the citizens, the sculpture was built between October 2010 and January 2011. Since December 2011, the Munich tram drives through it.

Nikon D3200

The Nikon D3200 is a 24.2-megapixel DX format DSLR Nikon F-mount camera officially launched by Nikon on April 19, 2012.

It is marketed as an entry-level DSLR camera for beginners and experienced DSLR hobbyists who are ready for more advanced specs and performance.

Use especially for beginners can be assisted by guide modes (integrated tutorials). It replaces the D3100 as Nikon's entry level DSLR, but its improved image quality has been compared to that of pro DSLRs. Based on DxOMark, the Nikon D3200 entry-level crop DSLR surpassed the DxOMark Overall Sensor Score of the fullframe Canon EOS 5D Mark II, although 5D Mark II was state-of-the-art when it was launched four years before.Its successor is the Nikon D3300 announced in January 2014 with new Nikon Expeed 4 image processor, without optical low pass filter (OLPF), 5 fps and the Nikon's first DSLR camera with Easy (sweep) Panorama. As in the Nikon D5300, the carbon-fiber-reinforced polymer body and also the new retractable kit lens makes it smaller and lighter.

Nikon D3300

Nikon D3300 is a 24.2-megapixel DX format DSLR Nikon F-mount camera officially launched by Nikon on January 7, 2014. It is marketed as an entry-level DSLR camera for beginners (offering tutorial- and improved guide-mode) and experienced DSLR hobbyist who are ready for more advanced specs and performance. It replaces the D3200 as Nikon's entry level DSLR. The D3300 usually comes with an 18-55mm VR II kit lens, which is the upgraded model of older VR (Vibration Reduction) lens.

The Expeed 4 image-processing engine enables the camera to capture 60 fps 1080p video in MPEG-4 format. And 24.2 megapixel images without optical low-pass filter (OLPF, anti-aliasing (AA) filter) at 5 fps as the fastest for low-entry DSLR. It is Nikon's first DSLR camera with Easy (sweep) Panorama. As in the Nikon D5300, the carbon-fiber-reinforced polymer body and also the new retractable kit lens makes it smaller and lighter. The camera body is approx. 124 x 98 x 75.5 mm and weighs 460 g with and 410 g without battery and memory card.

In April 2014, the D3300 received a Technical Image Press Association (TIPA) award in the category "Best Digital SLR Entry Level".The D3300 was superseded as Nikon's entry-level camera by the D3400 in late 2016.

Nikon D5300

The Nikon D5300 is an F-mount DSLR with a new carbon-fiber-reinforced polymer body and other new technologies, announced by Nikon on October 17, 2013.It features the new Expeed 4 processor and is the company's first DSLR with built-in Wi-Fi and GPS. It shares the same 24-megapixel image sensor as its D5200 predecessor, but without an anti-aliasing (AA) filter, equal to the Nikon D7100. MSRP for the body is $800, and $1,400 with an 18-140mm f/3.5-5.6 kit lens. The camera replaces the D5200 and is replaced by the Nikon D5500.

Nikon D750

The Nikon D750 is a full-frame DSLR camera announced by Nikon on September 12, 2014. It is the first in a new line of Nikon FX format cameras which includes technologies from the D810 in a smaller and lighter body. Nikon sees the D750 with "advanced video features" for videographers as well as a primary or secondary camera for fast handling and speed. The camera can shoot at 6.5 fps at full resolution.It has a newly developed 24.3-effective-megapixel image sensor (24.93 megapixel raw) with claimed lower image noise. The Expeed 4 processor from D4S/D810 and built-in Wi-Fi enable functions from the D810. Its autofocus is the same as in the D4S and D810, but can autofocus with less light than the D810, down to -3 EV.The D750 has a tilting LCD screen (the first full-frame DSLR with an adjustable screen, although several Nikon DX bodies have tilting or fully articulated screens), and is cited as "the lightest among Nikon's traditional pro series". The body is a light-weight weather-sealed monocoque construction with carbon-fiber-reinforced polymer at the front and magnesium alloy for the back and top.

Pariss

Pariss is an electric sports car from Paris, France. Damien Biro, whose grandfather and great-uncle László Bíró invented the modern ballpoint pen in 1938, is the builder of the Pariss Electric Roadster. It has two lithium-ion batteries, one powering the front wheels and one powering the rear and a Carbon-fiber-reinforced polymer body.

Plug

Plug, PLUG, plugs, or plugged may refer to:

Plug (accounting), an unsupported adjustment to an accounting record

Plug (fishing), a family of fishing lures

Plug (horticulture), a planting technique

Plug (jewellery), a type of jewellery worn in stretched piercings

Plug (sanitation), a stopper for a drainage outlet

Butt plug, a sex toy that is inserted into the rectum

Core plug, used to fill the casting holes on engines

Earplug for ear protection

Fusible plug, a safety device in steam boilers

Hair plug, hair that has undergone hair transplantation

Mating plug, secretion used in the mating of some animal species

Plug, a step in the manufacturing process for parts made of carbon-fiber-reinforced polymer

Plug, a type of chewing tobacco made by pressing tobacco with syrup

Plug computer, a type of small-form-factor computer

Portland Linux/Unix Group (PLUG), a group of Linux enthusiasts in Portland, Oregon

Product plug, or product placement in marketing

Volcanic plug, a geological landform

Wall plug, a fastener that allows screws to be fitted into masonry walls

Tecnam P2010

The Tecnam 2010 is a four-seat, high wing, single engine light aircraft of mixed metal and carbon-fiber-reinforced polymer construction. Designed and built in Italy, it was first presented in public in April 2011.

Warp Drive Inc

Warp Drive Inc is an American manufacturer of composite propellers for ultralight aircraft, ultralight trikes, light-sport aircraft, amateur-built aircraft, gyrocopter, airboats and other non-certified applications. The company is based in Ventura, Iowa.The company makes its propellers from solid carbon-fiber-reinforced polymer.

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