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48-731: Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe . In 1960, it became the first crewed vessel to reach the bottom of Challenger Deep in the Mariana Trench , the deepest point in Earth's seabed. The mission was the final goal for Project Nekton , a series of dives conducted by the United States Navy in the Pacific Ocean near Guam . The vessel was piloted by Swiss oceanographer Jacques Piccard and US Navy lieutenant Don Walsh . They reached

96-845: A brittle manner when under load, especially under an impact force , and is more prone to scratching than conventional inorganic glass, but modified PMMA is sometimes able to achieve high scratch and impact resistance. PMMA is a strong, tough, and lightweight material. It has a density of 1.17–1.20 g/cm , which is approximately half that of glass, which is generally, depending on composition, 2.2–2.53 g/cm . It also has good impact strength, higher than both glass and polystyrene, but significantly lower than polycarbonate and some engineered polymers. PMMA ignites at 460 °C (860 °F) and burns , forming carbon dioxide , water , carbon monoxide , and low-molecular-weight compounds, including formaldehyde . PMMA transmits up to 92% of visible light (3 mm (0.12 in) thickness), and gives

144-422: A casting resin, in inks and coatings, and for many other purposes. It is often technically classified as a type of glass , in that it is a non-crystalline vitreous substance—hence its occasional historic designation as acrylic glass . The first acrylic acid was created in 1843. Methacrylic acid , derived from acrylic acid , was formulated in 1865. The reaction between methacrylic acid and methanol results in

192-449: A depth of 11,521 metres (37,799 ft), although this was revised later to 10,916 metres (35,814 ft); fairly recently, more accurate measurements have found Challenger Deep to be between 10,911 metres (35,797 ft) and 10,994 metres (36,070 ft) deep. The descent to the ocean floor took 4 hours 47 minutes at a descent rate of 0.9 metres per second (3.2 km/h; 2.0 mph). After passing 9,000 metres (30,000 ft), one of

240-646: A depth of about 10,916 metres (35,814 ft). The bathyscaphe was designed by Swiss scientist Auguste Piccard , the father of pilot Jacques Piccard. It was built in Italy and first launched in 1953. The vessel was first owned and operated by the French Navy until it was purchased by the US Navy in 1958. It was taken out of service in 1966. Since the 1980s, it has been on exhibit in the National Museum of

288-790: A reflection of about 4% from each of its surfaces due to its refractive index (1.4905 at 589.3   nm). It filters ultraviolet (UV) light at wavelengths below about 300 nm (similar to ordinary window glass). Some manufacturers add coatings or additives to PMMA to improve absorption in the 300–400 nm range. PMMA passes infrared light of up to 2,800 nm and blocks IR of longer wavelengths up to 25,000 nm. Colored PMMA varieties allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example). PMMA swells and dissolves in many organic solvents ; it also has poor resistance to many other chemicals due to its easily hydrolyzed ester groups. Nevertheless, its environmental stability

336-643: Is 105 °C (221 °F). The T g values of commercial grades of PMMA range from 85 to 165 °C (185 to 329 °F); the range is so wide because of the vast number of commercial compositions that are copolymers with co-monomers other than methyl methacrylate. PMMA is thus an organic glass at room temperature; i.e., it is below its T g . The forming temperature starts at the glass transition temperature and goes up from there. All common molding processes may be used, including injection molding , compression molding , and extrusion . The highest quality PMMA sheets are produced by cell casting , but in this case,

384-400: Is a commonly used material in modern dentistry, particularly in the fabrication of dental prosthetics, artificial teeth, and orthodontic appliances. Methyl methacrylate " synthetic resin " for casting (simply the bulk liquid chemical) may be used in conjunction with a polymerization catalyst such as methyl ethyl ketone peroxide (MEKP), to produce hardened transparent PMMA in any shape, from

432-515: Is an economical alternative to polycarbonate (PC) when tensile strength , flexural strength , transparency , polishability, and UV tolerance are more important than impact strength , chemical resistance, and heat resistance. Additionally, PMMA does not contain the potentially harmful bisphenol-A subunits found in polycarbonate and is a far better choice for laser cutting. It is often preferred because of its moderate properties, easy handling and processing, and low cost. Non-modified PMMA behaves in

480-412: Is at about 8,000–8,500 m (26,200–27,900 ft), beyond which they would become hyperosmotic . Invertebrates such as sea cucumbers , some of which potentially could be mistaken for flatfish, have been confirmed at depths of 10,000 m (33,000 ft) and more. Walsh later said that their original observation could be mistaken as their knowledge of biology was limited. Piccard and Walsh noted that

528-519: Is poly(methyl 2-methylprop en oate). (It is a common mistake to use "an" instead of "en".) Although PMMA is often called simply "acrylic", acrylic can also refer to other polymers or copolymers containing polyacrylonitrile . Notable trade names and brands include Acrylite, Altuglas, Astariglas, Cho Chen, Crystallite, Cyrolite, Hesalite (when used in Omega watches ), Lucite, Optix, Oroglas, PerClax, Perspex, Plexiglas, R-Cast, and Sumipex. PMMA

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576-574: Is rarely sold as an end product, since it is not optimized for most applications. Rather, modified formulations with varying amounts of other comonomers , additives, and fillers are created for uses where specific properties are required. For example: PMMA is routinely produced by emulsion polymerization , solution polymerization , and bulk polymerization . Generally, radical initiation is used (including living polymerization methods), but anionic polymerization of PMMA can also be performed. The glass transition temperature ( T g ) of atactic PMMA

624-500: Is superior to most other plastics such as polystyrene and polyethylene, and therefore it is often the material of choice for outdoor applications. PMMA has a maximum water absorption ratio of 0.3–0.4% by weight. Tensile strength decreases with increased water absorption. Its coefficient of thermal expansion is relatively high at (5–10)×10  °C . The Futuro house was made of fibreglass-reinforced polyester plastic, polyester-polyurethane, and poly(methylmethacrylate); one of them

672-470: Is the synthetic polymer derived from methyl methacrylate . It is used as an engineering plastic , and it is a transparent thermoplastic . PMMA is also known as acrylic , acrylic glass , as well as by the trade names and brands Crylux , Hesalite , Plexiglas , Acrylite , Lucite , and Perspex , among several others ( see below ). This plastic is often used in sheet form as a lightweight or shatter-resistant alternative to glass . It can also be used as

720-651: The Ateliers de Constructions Mécaniques de Vevey . The new sphere was also steel, but smaller at 2.16 metres (7.1 ft) diameter and with thicker walls, at 127 millimetres (5.0 in), calculated to withstand the 1,250 kilograms per square centimetre (123 MPa) pressure at the bottom of Challenger Deep plus a substantial factor of safety . The new sphere weighed 14.25 metric tons (31,400 pounds) in air and eight metric tons (18,000 pounds) in water giving it an average specific gravity 2.6 times (or 1.6 times greater than) that of seawater (13÷(13−8)). Outside observations by

768-610: The Batiscafo Trieste . Beginning in April 1963, Trieste was modified and used in the Atlantic Ocean to search for the missing nuclear submarine USS  Thresher  (SSN-593) . Trieste was delivered to Boston Harbor by USS Point Defiance (LSD-31) under the command of Captain H. H. Haisten. In August 1963, Trieste found debris of the wreck off the coast of New England , 2,560 m (8,400 ft) below

816-656: The Isle of Capri on the Mediterranean Sea it was operated in the Mediterranean by the French Navy for several years until it was purchased by the United States Navy in 1958 for US$ 250,000, equivalent to $ 2.6 million today. Trieste consisted of a heavy crew sphere suspended from a hull containing tanks filled with gasoline (petrol) for buoyancy , ballast hoppers filled with iron shot and floodable water tanks to sink. This general configuration remained

864-492: The Trieste , which was equipped with a powerful light, noted that the seafloor consisted of diatomaceous ooze and reported observing "some type of flatfish, resembling a sole , about 1 foot long and 6 inches across" (30 by 15 cm) lying on the seabed. This put to rest the question of whether or not there was life at such a depth in the complete absence of light. Acrylic glass Poly ( methyl methacrylate ) ( PMMA )

912-552: The Washington Navy Yard where it remains on exhibit today in the National Museum of the U.S. Navy , along with the Krupp pressure sphere. 38°52′24″N 76°59′43″W  /  38.87333°N 76.99528°W  / 38.87333; -76.99528 Bathyscaphe The float is filled with gasoline because it is readily available, buoyant, and, for all practical purposes, incompressible. The incompressibility of

960-491: The Cantiere navale di Castellammare di Stabia , near Naples . The pressure sphere was attached to the underside of the hull and accommodated two crew who accessed it via a vertical shaft through the hull; this access shaft was not pressurized and flooded with seawater on descent. The sphere was completely self-contained, having a closed-circuit rebreather system with oxygen provided from cylinders while carbon dioxide

1008-626: The M1911A1 pistol or clear handle grips for the M1 bayonet or theater knifes so that soldiers could put small photos of loved ones or pin-up girls' pictures inside. They were called "Sweetheart Grips" or "Pin-up Grips". Others were used to make handles for theater knives made from scrap materials and people who made them got artistic or creative. Civilian applications followed after the war. Common orthographic stylings include polymethyl methacrylate and polymethylmethacrylate . The full IUPAC chemical name

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1056-617: The United States Navy in Washington, D.C. Trieste was designed by the Swiss scientist Auguste Piccard, based on his previous experience with the bathyscaphe FNRS-2 . The term bathyscaphe refers to its capacity to dive and manoeuvre untethered to a ship in contrast to a bathysphere , bathys being ancient Greek meaning "deep" and scaphe being a light, bowl-shaped boat. Built in Italy and launched on 26 August 1953 near

1104-487: The balloon used for Piccard's ascent into the stratosphere in 1938). Propulsion was provided by battery -driven electric motors . The float held 37,850 litres (8,330 imp gal; 10,000 US gal) of aviation gasoline. There was no access tunnel; the sphere had to be loaded and unloaded while on deck. The first journeys were detailed in the Jacques Cousteau book The Silent World . As described in

1152-662: The book, "the vessel had serenely endured the pressure of the depths, but had been destroyed in a minor squall". FNRS-3 was a new submersible, using the crew sphere from the damaged FNRS-2 , and a new larger 75,700 litres (16,700 imp gal; 20,000 US gal) float. Piccard's second bathyscaphe was actually a third vessel Trieste , which was purchased by the United States Navy from Italy in 1957. It had two water ballast tanks and eleven buoyancy tanks holding 120,000 litres (26,000 imp gal; 32,000 US gal) of gasoline. In 1960 Trieste , carrying Piccard's son Jacques Piccard and Don Walsh , reached

1200-437: The craft to sink, and its release caused it to ascend. The iron shot was locked in place at the throats of the hoppers by electromagnets and was released either by switching the electromagnets off or in the event of an electrical failure. Progressive release allowed buoyancy trim. Compressed-air–driven variable-buoyancy pressure vessels typically used in submarines are not feasible at extreme pressure. Water tanks at each end of

1248-470: The craft was designed to operate are too great. For example, the pressure at the bottom of the Challenger Deep is more than seven times that in a standard "H-type" compressed gas cylinder . Instead, ballast in the form of iron shot is released to ascend, the shot being lost to the ocean floor. The iron shot containers are in the form of one or more hoppers which are open at the bottom throughout

1296-408: The crew were made through a porthole made from a single, tapered block of acrylic glass ; the only transparent material available that could withstand the pressure. Outside illumination was by quartz arc-light bulbs, which could withstand the pressure without modification. The buoyancy tanks were filled with gasoline, which floats in water and is similarly incompressible . Changes in the volume of

1344-605: The deepest known point on the Earth's surface, the Challenger Deep , in the Mariana Trench in the Pacific Ocean. The onboard systems indicated a depth of 37,800 ft (11,521 m) but this was later corrected to 35,813 ft (10,916 m) by taking into account variations arising from salinity and temperature. Later and more accurate measurements made in 1995 have found the Challenger Deep to be slightly shallower at 35,798 ft (10,911 m). The crew of

1392-542: The dive, the iron shot being held in place by an electromagnet at the neck. This is a fail-safe device as it requires no power to ascend; in fact, in the event of a power failure, shot runs out by gravity and ascent is automatic. The first bathyscaphe was dubbed FNRS-2 , named after the Fonds National de la Recherche Scientifique , and built in Belgium from 1946 to 1948 by Auguste Piccard . ( FNRS-1 had been

1440-586: The entire surface of the cut parts, at great distances from the stressed edge. Annealing the PMMA sheet/parts is therefore an obligatory post-processing step when intending to chemically bond lasercut parts together. In the majority of applications, PMMA will not shatter. Rather, it breaks into large dull pieces. Since PMMA is softer and more easily scratched than glass, scratch-resistant coatings are often added to PMMA sheets to protect it (as well as possible other functions). Pure poly(methyl methacrylate) homopolymer

1488-411: The ester methyl methacrylate . It was developed in 1928 in several different laboratories by many chemists, such as William R. Conn, Otto Röhm , and Walter Bauer, and first brought to market in 1933 by German Röhm & Haas AG (as of January 2019, part of Evonik Industries ) and its partner and former U.S. affiliate Rohm and Haas Company under the trademark Plexiglas. Polymethyl methacrylate

Trieste (bathyscaphe) - Misplaced Pages Continue

1536-466: The first bathyscaphe, composed the name bathyscaphe using the Ancient Greek words βαθύς ( bathús ), meaning "deep", and σκάφος ( skáphos ), meaning "vessel, ship". To descend, a bathyscaphe floods air tanks with sea water, but unlike a submarine the water in the flooded tanks cannot be displaced with compressed air to ascend, because the water pressures at the depths for which

1584-580: The floor of the Challenger Deep consisted of " diatomaceous ooze". The ascent took 3 hours and 15 minutes. The National Museum of the Navy commemorated the 60th anniversary of the dive in January 2020. The Trieste performed a number of deep dives in the Mediterranean prior to being purchased by the U.S. Navy in 1958. It conducted 48 dives exceeding 3,700 metres (12,100 ft) between 1953 and 1957 as

1632-746: The form of sheets affords to shatter resistant panels for building windows, skylights, bulletproof security barriers, signs and displays, sanitary ware (bathtubs), LCD screens, furniture and many other applications. It is also used for coating polymers based on MMA provides outstanding stability against environmental conditions with reduced emission of VOC. Methacrylate polymers are used extensively in medical and dental applications where purity and stability are critical to performance. In particular, acrylic-type lenses are useful for cataract surgery in patients that have recurrent ocular inflammation (uveitis), as acrylic material induces less inflammation. Due to its aforementioned biocompatibility, poly(methyl methacrylate)

1680-611: The freighter Santa Maria to participate in Project Nekton , a series of very deep dives in the Mariana Trench. On 23 January 1960, it reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, crewed or uncrewed, had reached the deepest known point of the Earth's oceans. The onboard systems indicated

1728-405: The gasoline caused by any slight compression or temperature changes were accommodated by the free flow of seawater into and out of the bottom of the tanks during a dive via valves, equalising the pressure and allowing them to be lightly built. Ballast was held in two conical hoppers fore and aft of the crew sphere each containing 9 metric tons (20,000 pounds) of iron shot. This shot ballast allowed

1776-413: The gasoline means the tanks can be very lightly constructed, since the pressure inside and outside the tanks equalizes, eliminating any differential. By contrast, the crew cabin must withstand a huge pressure differential and is massively built. Buoyancy at the surface can be trimmed easily by replacing gasoline in the tanks with water, because water has a greater density. Auguste Piccard , inventor of

1824-700: The glass as a clear plastic sheet, which Röhm gave the trademarked name Plexiglas in 1933. Both Perspex and Plexiglas were commercialized in the late 1930s. In the United States, E.I. du Pont de Nemours & Company (now DuPont Company) subsequently introduced its own product under the trademark Lucite. In 1936 ICI Acrylics (now Lucite International) began the first commercially viable production of acrylic safety glass. During World War II both Allied and Axis forces used acrylic glass for submarine periscopes and aircraft windscreen, canopies, and gun turrets. Scraps of acrylic were also used to make clear pistol grips for

1872-542: The hull were pumped out for flotation, lifting, and towing on the surface and fully flooded to allow sinking. Following its acquisition by the United States Navy, Trieste was modified extensively by the Naval Electronics Laboratory , San Diego , California, tested in the Pacific Ocean over the next few years, and culminated in a dive to the bottom of Challenger Deep 23 January 1960. Trieste departed San Diego on 5 October 1959 for Guam aboard

1920-463: The outer Plexiglas window panes cracked, shaking the entire vessel. The two men spent twenty minutes on the ocean floor. The temperature in the cabin was 7 °C (45 °F) at the time. While at maximum depth, Piccard and Walsh unexpectedly regained the ability to communicate with the support ship, USS Wandank (ATA-204) , using a sonar / hydrophone voice communications system. At a speed of almost 1.6 km/s (1 mi/s) – about five times

1968-517: The polymerization and molding steps occur concurrently. The strength of the material is higher than molding grades owing to its extremely high molecular mass . Rubber toughening has been used to increase the toughness of PMMA to overcome its brittle behavior in response to applied loads. Being transparent and durable, PMMA is a versatile material and has been used in a wide range of fields and applications such as rear-lights and instrument clusters for vehicles, appliances, and lenses for glasses. PMMA in

Trieste (bathyscaphe) - Misplaced Pages Continue

2016-463: The same but after modifications to the hull for Project Nekton , which included the dive to Challenger Deep, Trieste was more than 15 metres (49 ft) long. The hull was built by Cantieri Riuniti dell'Adriatico , in the Free Territory of Trieste on the border between Italy and Yugoslavia, now in Italy, hence the name. The pressure sphere was built separately and installed on the hull in

2064-439: The speed of sound in air – it took about seven seconds for a voice message to travel from the craft to the support ship and another seven seconds for answers to return. While at the bottom, Piccard and Walsh reported observing a number of sole and flounder (both flatfish ). The accuracy of this observation has later been questioned and recent authorities do not recognize it as valid. The theoretical maximum depth for fish

2112-538: The surface after several dives. Trieste 's participation in the search earned it the Navy Unit Commendation . Following the mission, Trieste was returned to San Diego and taken out of service in 1966. Between 1964 and 1966, Trieste was used to develop its replacement, the Trieste II , with the original Terni pressure sphere reincorporated in its successor. In early 1980, it was transported to

2160-564: The surface of the material. Laser cutting may be used to form intricate designs from PMMA sheets. PMMA vaporizes to gaseous compounds (including its monomers) upon laser cutting, so a very clean cut is made, and cutting is performed very easily. However, the pulsed lasercutting introduces high internal stresses, which on exposure to solvents produce undesirable "stress- crazing " at the cut edge and several millimetres deep. Even ammonium-based glass-cleaner and almost everything short of soap-and-water produces similar undesirable crazing, sometimes over

2208-657: Was scrubbed from the air by being passed through canisters of soda-lime . Batteries provided electrical power. Piccard's original pressure sphere was built by Acciaierie, Terni of steel forged in two hemispheres and welded to form a sphere 2.4 metres (7.9 ft) in diameter and 89 millimetres (3.5 in) thick, This pressure sphere was replaced in December 1958 with another cast by the Krupp Steel Works of Essen, Germany in three sections; an equatorial ring and two caps, which were finely machined and joined by

2256-539: Was discovered in the early 1930s by British chemists Rowland Hill and John Crawford at Imperial Chemical Industries (ICI) in the United Kingdom. ICI registered the product under the trademark Perspex. About the same time, chemist and industrialist Otto Röhm of Röhm and Haas AG in Germany attempted to produce safety glass by polymerizing methyl methacrylate between two layers of glass. The polymer separated from

2304-420: Was found to be degrading by cyanobacteria and Archaea . PMMA can be joined using cyanoacrylate cement (commonly known as superglue ), with heat (welding), or by using chlorinated solvents such as dichloromethane or trichloromethane (chloroform) to dissolve the plastic at the joint, which then fuses and sets, forming an almost invisible weld . Scratches may easily be removed by polishing or by heating

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