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74-672: Pitons were the original form of protection and are still used where there is no alternative. Repeated hammering and extraction of pitons damage the rock, and climbers who subscribe to the clean climbing ethic avoid their use as much as possible. With the popularization of clean climbing in the 1970s, pitons were largely replaced by faster and easier-to-use clean protection, such as nuts and camming devices . Pitons are still found in place (as "fixed" pitons) on some established free climbing routes, as fixed belay station anchors, in places where nuts or cams do not work; and are used on some hard aid climbs. Pitons are sized and manufactured to fit

148-415: A "bent gate" on the lower carabiner to make clipping-into the quickdraw even easier. Several devices are used for controlling the rope (e.g. belay devices and self-locking devices), moving up the rope (e.g. ascender devices), or moving down the rope (e.g. rappel/abseil or descender devices). These actions were historically performed by climbers with no mechanical devices (e.g. the body belay for belaying,

222-516: A fixed or static rope that is hanging from a fixed anchor. They perform the same basic function as the dülfersitz abseil but with more control and less effort. The classic passive descender, and still widely used, is the figure-eight , although it is offered in more complex variations with "ears" and "wings" to prevent the rope from locking up. Many passive belay devices can be used as descenders, such as tubers/tubulars. Some modern descenders come with self-locking device (SLD) features that will grip

296-530: A good abrasion resistance but is better suited to soft mating surfaces. Fluoropolymer / HMWPE insulation cathodic protection cable is typically made with dual insulation. It features a primary layer of a fluoropolymer such as ECTFE which is chemically resistant to chlorine, sulfuric acid, and hydrochloric acid . Following the primary layer is an HMWPE insulation layer, which provides pliable strength and allows considerable abuse during installation. The HMWPE jacketing provides mechanical protection as well. UHMWPE

370-568: A harness to a rope (or other anchor points, such as a metal cable). The difference is that lanyards are much stronger than quickdraws and are capable of withstanding fall factors of 2 as found on via ferrata or on multi-pitch climbing routes. They are often made from materials that can absorb dynamic energy and often come with additional optional fall energy absorption devices, and lanyards that have had heavy falls often have to be discarded. Lanyards are also constructed to be sufficiently flexible to resist being twisted. A sub-class of lanyards

444-620: A longer version of a quickdraw or a makeshift lanyard. Slings can be made into more complex pieces of equipment such as the daisy chain , which is used in aid climbing, and the Personal Anchor System , which is used in securing a climber to a fixed anchor point. While lengths of webbing can be tied via a knot, such as a water knot , to create custom-length loops instead of the pre-sewn fixed-length slings, their load-bearing capacity can be materially reduced making them less safe. Climbers instead use cord (or "accessory cord"), which

518-435: A short, pre-sewn loop of webbing. They are used to reduce the friction and drag between the rope and the fixed point that can occur when the rope is just clipped into a carabiner clipped into the fixed point. In competition climbing , the quickdraws are already hanging from the pre-fixed bolts, which is called pinkpointing in sport climbing . The quickdraws used in advanced sport and in competition climbing routes often have

592-489: A similar manner, aromatic polymers are often susceptible to aromatic solvents due to aromatic stacking interactions , an effect aliphatic polymers like UHMWPE are immune to. Since UHMWPE does not contain chemical groups (such as esters , amides , or hydroxylic groups) that are susceptible to attack from aggressive agents, it is very resistant to water, moisture, most chemicals, UV radiation, and micro-organisms. Under tensile load, UHMWPE will deform continually as long as

666-894: A specific gravity of roughly 7.8, these materials have a strength-to-weight ratios eight times that of high-strength steels. Strength-to-weight ratios for UHMWPE are about 40% higher than for aramid . The high qualities of UHMWPE filament were discovered by Albert Pennings in 1968, but commercially viable products were made available by DSM in 1990 and Southern Ropes soon after. Derivatives of UHMWPE yarn are used in composite plates in armor , in particular, personal armor and on occasion as vehicle armor . Civil applications containing UHMWPE fibers are cut-resistant gloves, tear-resistant hosiery , bow strings, climbing equipment , automotive winching , fishing line , spear lines for spearguns , high-performance sails , suspension lines on sport parachutes and paragliders , rigging in yachting , kites, and kite lines for kites sports. For personal armor,

740-409: A wide range of cracks. From small to large, the most common are: Early pitons were made of malleable iron and soft steel and would deform to the shape of a crack when hammered into the rock, which worked well in the irregular cracks found on European limestone. Soft pitons are difficult to remove without damaging the piton, so they were left in place and became fixed anchor points on a climb. During

814-487: Is synthesized from its monomer ethylene , which is bonded together to form the base polyethylene product. These molecules are several orders of magnitude longer than those of familiar high-density polyethylene (HDPE) due to a synthesis process based on metallocene catalysts , resulting in UHMWPE molecules typically having 100,000 to 250,000 monomer units per molecule each compared to HDPE's 700 to 1,800 monomers. UHMWPE

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888-711: Is a length of thinner approximately 4–8 mm static kernmantle rope , tied via a double fisherman's knot into closed loops of any size. Cord loops (also known as " cordelettes ") serve a wide variety of functions in rock climbing. Uses include creating friction prusik knots for ascending or gripping fixed climbing ropes, usually using thinner approximately 5–6  mm cord, or for attaching to, and equalizing forces across, multiple fixed anchors points, such as when setting up abseil or belay anchors on multi-pitch climbing routes, usually using thicker approximately 7–8  mm cord. Several modern pieces of rope connecting equipment help climbers to securely attach items to

962-677: Is also almost completely inelastic, which can exacerbate the opening shock. For that reason, Dacron lines continue to be used in student and some tandem systems, where the added bulk is less of a concern than the potential for an injurious opening. In turn, in high-performance parachutes used for swooping , UHMWPE is replaced with Vectran and HMA (high-modulus aramid), which are even thinner and dimensionally stable, but exhibit greater wear and require much more frequent maintenance to prevent catastrophic failure. UHMWPE are also used for reserve parachute closing loops when used with automatic activation devices , where their extremely low coefficient of friction

1036-430: Is available commercially either as fibers or in consolidated form, such as sheets or rods. Because of its resistance to wear and impact, UHMWPE continues to find increasing industrial applications, including the automotive and bottling sectors. Since the 1960s, UHMWPE has also been the material of choice for total joint arthroplasty in orthopedic and spine implants. UHMWPE fibers branded as Dyneema, commercialized in

1110-504: Is broadly classed as Personal Protective Equipment (PPE). The International Climbing and Mountaineering Federation (known as the UIAA) was an important early body—and the only body pre-1995—in setting standards for climbing equipment. The UIAA Safety Commission continues to play a central worldwide role in this area. The European Committee for Standardization (CEN) is also an important major regulatory body for PPE, and which works closely with

1184-416: Is clipped into any given anchor or protection point), which have a reduced thickness of approximately 8–9  mm to limit the weight of the extra rope. Twin roping uses two thinner ropes, typically 7–8  mm in thickness, which are both clipped into each protection point. Twin roping is thus not used for reducing rope drag, but to have a backup rope on long climbs. Modern webbing (or "tape")

1258-432: Is comparable to that of polytetrafluoroethylene (PTFE, Teflon), but UHMWPE has better abrasion resistance than PTFE. Polymerization of UHMWPE was commercialized in the 1950s by Ruhrchemie AG, which has changed names over the years. Today UHMWPE powder materials, which may be directly molded into a product's final shape, are produced by Ticona , Braskem , Teijin (Endumax), Celanese , and Mitsui . Processed UHMWPE

1332-691: Is critical for proper operation in the event of cutter activation. UHMWPE has a clinical history as a biomaterial for use in hip, knee, and (since the 1980s), for spine implants. An online repository of information and review articles related to medical grade UHMWPE, known as the UHMWPE Lexicon, was started online in 2000. Joint replacement components have historically been made from "GUR" resins. These powder materials are produced by Ticona, typically converted into semi-forms by companies such as Quadrant and Orthoplastics, and then machined into implant components and sterilized by device manufacturers. UHMWPE

1406-483: Is generally not recommended, and if necessary it is recommended to use the triple fisherman's knot rather than the traditional double fisherman's knot . Ships' hawsers and cables made from the fiber (0.97 specific gravity) float on sea water. "Spectra wires" as they are called in the towing boat community are commonly used for face wires as a lighter alternative to steel wires. It is used in skis and snowboards, often in combination with carbon fiber , reinforcing

1480-466: Is high. In this way, large tensile loads are not limited as much by the comparative weakness of each localized van der Waals force. When formed into fibers, the polymer chains can attain a parallel orientation greater than 95% and a level of crystallinity from 39% to 75%. In contrast, Kevlar derives its strength from strong bonding between relatively short molecules. The weak bonding between olefin molecules allows local thermal excitations to disrupt

1554-403: Is highly resistant to corrosive chemicals except oxidizing acids ; has extremely low moisture absorption and a very low coefficient of friction ; is self-lubricating (see boundary lubrication ); and is highly resistant to abrasion , in some forms being 15 times more resistant to abrasion than carbon steel . Its coefficient of friction is significantly lower than that of nylon and acetal and

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1628-456: Is made of strong tubular nylon or the even stronger spectra/dyneema material. Climbers use webbing that has been sewn using a certified standard of reinforced stitching into various lengths of closed loops called " slings " (or "runners"). They can be used in a wide range of situations, including wrapping around sections of rock for abseiling, creating belay anchors, or as passive protection, or tied to other equipment—often via carabiners—to create

1702-429: Is often used for winch-launching gliders from the ground, as, in comparison with steel cable, its superior abrasion resistance results in less wear when running along the ground and into the winch, increasing the time between failures. The lower weight on the mile-long cables used also results in higher winch launches. UHMWPE was used for the 30 km (19 mi) long, 0.6 mm (0.024 in) thick space tether in

1776-410: Is processed variously by compression moulding , ram extrusion , gel spinning , and sintering . Several European companies began compression molding UHMWPE in the early 1960s. Gel-spinning arrived much later and was intended for different applications. In gel spinning a precisely heated gel (of a low concentration of UHMWPE in an oil) is extruded through a spinneret . The extrudate is drawn through

1850-448: Is the easiest to clip into and out of for example when leading a bolted sport climbing route but with the risk that the gate may unintentionally open. Climbing harnesses are used for connecting the rope to the climber via a "belay loop" on the harness. Harnesses are made of strong materials to specific strength guidelines that can withstand the load of a major fall. There are many types of harness designs and materials used depending on

1924-693: Is the personal anchor system (PAS), which is a section of rope or interconnected chains of slings, which are used to tie the harness to an anchor point such as a belay station. Traditionally, climbers would tie their harness to anchors using part of the climbing rope; however, the PAS has become popular as a way to avoid reducing the effective length of the climbing rope, and to use a more straightforward connection. Quickdraws are used by climbers to connect ropes to fixed points such as bolted anchors in sport climbing, or protection devices in traditional climbing. The quickdraw consists of two non-locking carabiners connected by

1998-555: Is undertaken. Bouldering needs the least equipment outside of climbing shoes , climbing chalk and optional crash pads . Sport climbing adds ropes , harnesses , belay devices , and quickdraws to clip into pre-drilled bolts . Traditional climbing adds the need to carry a "rack" of temporary passive and active protection devices . Multi-pitch climbing , and the related big wall climbing , adds devices to assist in ascending and descending fixed ropes . Finally, aid climbing uses unique equipment to give mechanical assistance to

2072-470: The UIAA standards) for strength, durability, and reliability, and must be certified and tested against such standards with individual pieces carrying such certification marks. The rock-climbing equipment needed varies materially depending on the type of rock climbing being undertaken. Starting from the least equipment-intensive type of climbing, the general equipment needs are as follows: Rock-climbing equipment

2146-405: The dülfersitz abseil for descending, and the prusik knot for ascending), and these mechanical devices help with both control and safety in all conditions (e.g. wet or icy ropes). Ascenders (also called "jumars" or " crolls " after popular brands) are mechanical devices to enable a climber to move up a fixed rope , which is a static rope that is hanging from a fixed anchor. Ascenders perform

2220-611: The fiberglass composite material, adding stiffness and improving its flex characteristics. The UHMWPE is often used as the base layer, which contacts the snow, and includes abrasives to absorb and retain wax. It is also used in lifting applications, for manufacturing low weight, and heavy duty lifting slings. Due to its extreme abrasion resistance it is also used as an excellent corner protection for synthetic lifting slings. High-performance lines (such as backstays ) for sailing and parasailing are made of UHMWPE, due to their low stretch, high strength, and low weight. Similarly, UHMWPE

2294-566: The "Dyneema Purity" trade name. UHMWPE is used in the manufacture of PVC (vinyl) windows and doors, as it can endure the heat required to soften the PVC-based materials and is used as a form/chamber filler for the various PVC shape profiles in order for those materials to be 'bent' or shaped around a template. UHMWPE is also used in the manufacture of hydraulic seals and bearings. It is best suited for medium mechanical duties in water, oil hydraulics, pneumatics, and unlubricated applications. It has

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2368-492: The ESA/Russian Young Engineers' Satellite 2 of September, 2007. Dyneema Composite Fabric (DCF) is a laminated material consisting of a grid of Dyneema threads sandwiched between two thin transparent polyester membranes. This material is very strong for its weight, and was originally developed for use in racing yacht sails under the name 'Cuben Fiber'. More recently it has found new applications, most notably in

2442-547: The Petzl GriGri or the Wild Country Revo ). Some passive belay devices may also be used as descenders for abseiling . Indoor climbing walls can provide on-site fixed mechanical auto belay devices that enable the climber to top rope a route alone; more recent lead auto belay models allow the climber to also lead climb the route alone. Descenders (or abseil devices) enable a climber to abseil (or rappel) down

2516-884: The Petzl Traxion). The most complex use is for rope solo climbing , for which devices such as Wren's Silent Partner, the Petzel GriGri, and the Wild Country Revo have been used (rope solo climbing requires the widest range of rope devices including ascenders and descenders), or the more straightforward top rope solo climbing , for which the Petzl Micro Traxion and Camp Lift have been used. As discussed in types of climbing , rock climbing protection devices are mainly used in traditional climbing and in sport climbing, both of which can be done in single and multi-pitch formats. In addition, clean aid climbing also uses many of

2590-531: The UHMWPE fibers are blended with, for example, Vectran . In skydiving , UHMWPE is one of the most common materials used for suspension lines, largely supplanting the earlier-used Dacron , being lighter and less bulky. UHMWPE has excellent strength and wear-resistance, but is not dimensionally stable (i.e. shrinks) when exposed to heat, which leads to gradual and uneven shrinkage of different lines as they are subject to differing amounts of friction during canopy deployment, necessitating periodic line replacement. It

2664-431: The UHMWPE without the need for thermal treatment. Several companies have been selling antioxidant-stabilized joint replacement technologies since 2007, using both synthetic vitamin E as well as hindered phenol-based antioxidants. Another important medical advancement for UHMWPE in the past decade has been the increase in use of fibers for sutures . Medical-grade fibers for surgical applications are produced by DSM under

2738-771: The UIAA Safety Commission through its CEN Working Group for Mountaineering Equipment. North America has fewer specific regulations as rock-climbing equipment as it is not classed as military or professional PPE and thus does not fall under the American Occupational Safety and Health Administration (OSHA) regulations; in effect, the UIAA and CEN have become the most important bodies for setting standards and regulating rock-climbing equipment worldwide, and most major manufacturers, and distributors, produce equipment certified and stamped with UIAA and CE marking . After

2812-642: The United Kingdom left the European Union, it adopted the UKCA certification in place of the CEN. Modern climbing ropes are 50–80 metres (160–260 ft) in length—the longer versions are for multi-pitch climbing—and have a kernmantle construction consisting of a core kern of twisted nylon fibers and an outer sheath mantle of woven colored coarse nylon fibers. They are either dynamic ropes , which can stretch to absorb

2886-420: The air, the oil extracted with a solvent which does not affect the UHMWPE, and then dried removing the solvent. The end-result is a fiber with a high degree of molecular orientation, and therefore exceptional tensile strength . Gel spinning depends on isolating individual chain molecules in the solvent so that intermolecular entanglements are minimal. Entanglements make chain orientation more difficult, and lower

2960-422: The case of a fall), or passive (i.e., they maintain a static position throughout). Fixed protection devices are permanent on-site anchors to which a lead climber can clip their rope – often via a quickdraw – when they are sport climbing ; they also can be used to create anchor points for belaying and abseiling. The main types are: Aid climbing uses several of the above devices but in a way that gives "aid" to

3034-422: The climber in ascending (e.g. pulling up on pitons and hooks). There are also a number of other pieces of equipment that are more exclusively associated with aid climbing. Rock climbers use several pieces of specialized clothing equipment including: Rock climbers may also use a range of other specialized equipment including: Various items of equipment are employed during climbing-specific training to strengthen

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3108-429: The climber in their upward movement (e.g. aiders ). Advances in equipment are a key part of the rock climbing history , starting with the climbing rope . Modern devices enable climbers to perform tasks previously done manually, with greater control – in all conditions – and with less effort. Examples of replacements include the harness (replaced tying the rope around the waist), the carabiner (replaced many knots ),

3182-420: The climber's fingers, tendons, and muscles: Ultra high molecular weight polyethylene Ultra-high-molecular-weight polyethylene ( UHMWPE , UHMW ) is a subset of the thermoplastic polyethylene . Also known as high-modulus polyethylene ( HMPE ), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu . The longer chain serves to transfer load more effectively to

3256-701: The climbing rope, such as themselves via a modern climbing harness, or their various protection devices via modern carabiners and quickdraws. Before the invention of these pieces of rope-connecting equipment, climbers used alternative techniques such as looping the rope around the body instead of a harness (e.g. the body belay ) and looping the rope around various rocks as a form of protection. In addition to these early techniques, climbers also used various climbing knots to tie ropes and anchor points together, which are now all replaced by rope-connecting equipment such as carabiners. Carabiners are closed metal clips with spring-loaded gates that are used as connectors between

3330-451: The crystalline order of a given chain piece-by-piece, giving it much poorer heat resistance than other high-strength fibers. Its melting point is around 130 to 136 °C (266 to 277 °F), and, according to DSM, it is not advisable to use UHMWPE fibres at temperatures exceeding 80 to 100 °C (176 to 212 °F) for long periods of time. It becomes brittle at temperatures below −150 °C (−240 °F). The simple structure of

3404-673: The descender/abseil device (replaced the dülfersitz ), the ascender (replaced the prusik knot ), the belay device (replaced the body belay ), and nuts / hexes (replaced chockstones ). Modern equipment includes dynamic ropes , plyometric training tools, advanced spring-loaded camming devices (SLCDs) for protection, and advanced rope control devices such as self-locking devices (SLDs), progress capture devices (PCDs), and assisted braking devices (ABDs). Modern equipment uses advanced materials that are increasingly more durable, stronger, and lighter (e.g. spectra/dyneema and aluminum alloys ). The equipment must meet specific standards (e.g.

3478-405: The energy of a falling climber, or are the less expensive but more hard-wearing static ropes , which are only for use in constant-load situations such as descending (e.g. abseiling) and ascending (e.g. jumaring ). Some climbers will use a single full-thickness climbing rope of approximately 9–11  mm , and some will use double ropes , or "half-ropes", to reduce rope drag (e.g. one rope

3552-455: The equivalent monofilament line . In climbing , cord and webbing made of combinations of UHMWPE and nylon yarn have gained popularity for their low weight and bulk. They exhibit very low elasticity compared to their nylon counterparts, which translates to low toughness . The fiber's very high lubricity causes poor knot-holding ability, and it is mostly used in pre-sewn 'slings' (loops of webbing)—relying on knots to join sections of UHMWPE

3626-423: The equivalent steel wire rope would weigh around 13 kg (29 lb). One notable drawback of UHMWPE rope is its susceptibility to UV damage, so many users will fit winch covers in order to protect the cable when not in use. It is also vulnerable to heat damage from contact with hot components. Spun UHMWPE fibers excel as fishing line, as they have less stretch, are more abrasion -resistant, and are thinner than

3700-526: The ethics of many climbers. John Salathé pioneered designs using hardened steel which were much tougher than the European pitons. Salathé's pins, which he developed for a climb of the Lost Arrow , resisted deformation and were easier to remove and reuse, and were durable enough to be reused indefinitely. Protection (climbing) Rock-climbing equipment varies with the specific type of climbing that

3774-538: The exploration of the hard granite in Yosemite Valley in the 1950s and 1960s, it was found that soft pitons did not work well. The long routes developed in Yosemite made it impractical and costly to fix routes, and the soft pitons were not durable enough to be placed and removed more than a few times. Pitons needed to be removed and used again on subsequent pitches, sometimes many times. Leaving gear in place went against

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3848-654: The fibers are, in general, aligned and bonded into sheets, which are then layered at various angles to give the resulting composite material strength in all directions. Recently developed additions to the US Military's Interceptor body armor , designed to offer arm and leg protection, are said to utilize a form of UHMWPE fabric. A multitude of UHMWPE woven fabrics are available in the market and are used as shoe liners, pantyhose , fencing clothing, stab-resistant vests, and composite liners for vehicles. The use of UHMWPE rope for automotive winching offers several advantages over

3922-496: The late 1970s by the Dutch chemical company DSM , and as Spectra, commercialized by Honeywell (then AlliedSignal), are widely used in ballistic protection, defense applications, and increasingly in medical devices, sailing, hiking equipment, climbing, and many other industries. UHMWPE is a type of polyolefin . It is made up of extremely long chains of polyethylene, which all align in the same direction. It derives its strength largely from

3996-427: The length of each individual molecule (chain). Van der Waals forces between the molecules are relatively weak for each atom of overlap between the molecules, but because the molecules are very long, large overlaps can exist, adding up to the ability to carry larger shear forces from molecule to molecule. Each chain is attracted to the others with so many van der Waals forces that the whole of the inter-molecular strength

4070-638: The literature. Highly cross-linked UHMWPE materials were clinically introduced in 1998 and have rapidly become the standard of care for total hip replacements , at least in the United States. These new materials are cross-linked with gamma or electron beam radiation (50–105 kGy) and then thermally processed to improve their oxidation resistance. Five-year clinical data, from several centers, are now available demonstrating their superiority relative to conventional UHMWPE for total hip replacement (see arthroplasty ). Clinical studies are still underway to investigate

4144-410: The manufacture of lightweight and ultralight camping and backpacking equipment such as tents, backpacks, and bear-proof food bags. In archery, UHMWPE is widely used as a material for bowstrings because of its low creep and stretch compared to, for example, Dacron (PET). Besides pure UHMWPE fibers, most manufacturers use blends to further reduce the creep and stretch of the material. In these blends,

4218-436: The molecule also gives rise to surface and chemical properties that are rare in high-performance polymers. For example, the polar groups in most polymers easily bond to water. Because olefins have no such groups, UHMWPE does not absorb water readily, nor wet easily, which makes bonding it to other polymers difficult. For the same reasons, skin does not interact with it strongly, making the UHMWPE fiber surface feel slippery. In

4292-412: The more common steel wire rope . The key reason for changing to UHMWPE rope is improved safety. The lower mass of UHMWPE rope, coupled with significantly lower elongation at breaking, carries far less energy than steel or nylon, which leads to almost no snap-back . UHMWPE rope does not develop kinks that can cause weak spots, and any frayed areas that may develop along the surface of the rope cannot pierce

4366-612: The original passive braking devices like "sticht plates" and the later "tubers/tubulars" (e.g. the original Black Diamond ATC, or the Petzl Reverso ). The range of modern belay devices also includes auto-block devices (e.g. the GiGi ) allowing the belay device to be attached to a separate anchor point (e.g. and not to the belayer, which is useful for bringing up the second-climber on multi-pitch routes), and active assisted-braking devices (ABDs) that will self-lock with sudden rope movements (e.g.

4440-452: The performance of highly cross-linked UHMWPE for knee replacement. In 2007, manufacturers started incorporating anti-oxidants into UHMWPE for hip and knee arthroplasty bearing surfaces. Vitamin E (a-tocopherol) is the most common anti-oxidant used in radiation-cross-linked UHMWPE for medical applications. The anti-oxidant helps quench free radicals that are introduced during the irradiation process, imparting improved oxidation resistance to

4514-424: The polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. UHMWPE is odorless, tasteless, and nontoxic. It embodies all the characteristics of high-density polyethylene (HDPE) with the added traits of being resistant to concentrated acids and alkalis , as well as numerous organic solvents. It

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4588-411: The poor clinical history of Hylamer is largely attributed to its sterilization method, and there has been a resurgence of interest in studying this material (at least among certain research circles). Hylamer fell out of favor in the United States in the late 1990s with the development of highly cross-linked UHMWPE materials, however negative clinical reports from Europe about Hylamer continue to surface in

4662-475: The rope and various devices. Modern carabiners are made from a lightweight but strong aluminum alloy that can withstand the load of a fall. Carabiners come in various shapes, with the asymmetric/offset D-shape being the most common, and gate styles (e.g. a straight gate or a bent gate). A particular variation is whether the gate is locking, which gives extra security when belaying but makes the carabiner heavier and slightly tricker to clip into, or non-locking, which

4736-487: The rope in the event of an uncontrolled fall (e.g. the Petzl I'D S  [ de ] ). Heavy-duty descenders such as abseil racks are used for greater control and friction when carrying heavy loads and/or in very wet or icy conditions (e.g. big wall climbing and caving). The modern technique is to use a descender with a Personal Anchor System . Self-locking devices (SLDs), also called progress capture devices (PCDs), are

4810-449: The rope when pulled on in the opposite direction. To prevent the ascender device from accidentally falling off the rope, a locking carabiner is also used. Belay devices are mechanical friction-brake devices used to control the climbing rope(s) when belaying a climber. Their main purpose is to allow the rope to be locked off or fully braked with minimal effort when arresting a climber's fall. There are many kinds of belay devices, such as

4884-418: The same basic function as friction or prusik knots made from cord but far less effort and concentration are needed to use them (e.g. tired climbers at high-altitude), they can handle much heavier loads (e.g. climbers with ruck-sacks), and they are more reliable in all conditions (e.g. on wet and icy ropes). The ascender uses an internal cam that allows the device to slide freely in one direction but tightly grip

4958-485: The skin like broken steel wire strands can. UHMWPE rope is less dense than water, making water recoveries easier as the recovery cable is easier to locate than wire rope. The bright colours available also aid with visibility should the rope become submerged or dirty. Another advantage in automotive applications is the reduced weight of UHMWPE rope over steel cables. A typical 11 mm (0.43 in) UHMWPE rope of 30 m (98 ft) can weigh around 2 kg (4.4 lb),

5032-475: The strength of the final product. Dyneema and Spectra are brands of lightweight high-strength oriented-strand gels spun through a spinneret . They have yield strengths as high as 2.4 GPa (350,000 psi) and density as low as 0.97 g/mL (0.035 lb/cu in) (for Dyneema SK75). High-strength steels have comparable yield strengths, and low-carbon steels have yield strengths much lower (around 0.5 GPa (73,000 psi)). Since steel has

5106-498: The stress is present—an effect called creep . When UHMWPE is annealed , the material is heated to between 135 °C (275 °F) and 138 °C (280 °F) in an oven or a liquid bath of silicone oil or glycerine . The material is then cooled down at a rate of 5 °C/h (2.5 °F/ks) to 65 °C (149 °F) or less. Finally, the material is wrapped in an insulating blanket for 24 hours to bring to room temperature. Ultra-high-molecular-weight polyethylene (UHMWPE)

5180-403: The terms given to the broader class of rope devices that allow the climbing rope to move more freely in one direction but will lock quickly if the rope tries to move in the opposite direction. Their basic action means that several can also be used as emergency ascenders or assisted-belaying devices (ABDs), but they come in a broad range for a variety of uses (e.g. as a hauling or rescue pulley, like

5254-432: The traditional climbing protection devices. Temporary protection devices (also known as pro , gear or the rack ), provide the means to place temporary anchor points on the rock to which a lead climber can clip their rope (via a quickdraw) when traditional climbing ; they also can be used for anchor points for belaying and abseiling. The devices are categorized as being active (i.e. they dynamically move or adjust in

5328-524: The type of climbing undertaken. Examples include minimal "sit" harnesses for sport climbing as they require little in the way of gear-carrying loops, lightweight and detachable leg-loop harnesses for alpine climbing that fit around heaving winter clothing, padded harnesses for big wall climbing that give comfort for hanging belays and abseils, and chest/full-body harnesses for children or carrying heavy loads. Lanyards (or "teather", or "via ferrata set") are much longer versions of quickdraws that attach from

5402-450: Was first used clinically in 1962 by Sir John Charnley and emerged as the dominant bearing material for total hip and knee replacements in the 1970s. Throughout its history, there were unsuccessful attempts to modify UHMWPE to improve its clinical performance until the development of highly cross-linked UHMWPE in the late 1990s. One unsuccessful attempt to modify UHMWPE was by blending the powder with carbon fibers. This reinforced UHMWPE

5476-516: Was released clinically as "Poly Two" by Zimmer in the 1970s. The carbon fibers had poor compatibility with the UHMWPE matrix and its clinical performance was inferior to virgin UHMWPE. A second attempt to modify UHMWPE was by high-pressure recrystallization. This recrystallized UHMWPE was released clinically as "Hylamer" by DePuy in the late 1980s. When gamma irradiated in air, this material exhibited susceptibility to oxidation, resulting in inferior clinical performance relative to virgin UHMWPE. Today,

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