Misplaced Pages

#323676

46-580: Renovation began in November 1997, but the first steps were taken in 1995. Governor Mário Covas visualized the Julio Prestes Space as ideal for symphonic presentations and because OSESP did not have a permanent home at that time. Julio Prestes Station was built between 1926 and 1938 to be the headquarters and departure point of the Sorocabana Railway (EFS) - a company set up by coffee barons to ship

92-504: A branched polycarbonate. Both companies filed for U.S. patents in 1955, and agreed that the company lacking priority would be granted a license to the technology. Patent priority was resolved in Bayer's favor, and Bayer began commercial production under the trade name Makrolon in 1958. GE began production under the name Lexan in 1960, creating the GE Plastics division in 1973. After 1970,

138-657: A German scientist working at the University of Munich . However, after 30 years' laboratory research, this class of materials was abandoned without commercialization. Research resumed in 1953, when Hermann Schnell at Bayer in Uerdingen, Germany patented the first linear polycarbonate. The brand name "Makrolon" was registered in 1955. Also in 1953, and one week after the invention at Bayer, Daniel Fox at General Electric (GE) in Pittsfield, Massachusetts, independently synthesized

184-408: A high melting point. Polycarbonate is relatively difficult for casual hobbyists to print compared to thermoplastics such as Polylactic acid (PLA) or Acrylonitrile butadiene styrene (ABS) because of the high melting point, difficulty with print bed adhesion, tendency to warp during printing, and tendency to absorb moisture in humid environments. Despite these issues, 3D printing using polycarbonates

230-504: A stage elevator for a piano. The acoustic project was carefully designed to neutralize vibrations caused by the constant movement of trains. For this reason the main hall's 15 centimeter-thick floating floor was built on an immense neoprene slab which functions like a massive wedge between two concrete layers lined with Brazilian walnut, ideal material for absorbing noise. The floor was also lowered 1.22 m to respect acoustic requirements and avoid esthetic disfigurement. In order to complete

276-838: A unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Carbonate esters have planar OC(OC) 2 cores, which confer rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Polycarbonates received their name because they are polymers containing carbonate groups (−O−(C=O)−O−). A balance of useful features, including temperature resistance, impact resistance and optical properties, positions polycarbonates between commodity plastics and engineering plastics . The main polycarbonate material

322-400: Is a functionalist style of modern architecture characterised by predominantly rectilinear, orthogonal shapes, with regular horizontal rows of windows or glass walls. Dingbat apartments are an undistinguished shoebox style. The puritan and repetitive shoebox style is seen as a way to low-cost construction. Shoebox style concert halls of rectangular shape are also popular, as opposed to

368-599: Is a compound that is currently on the list of potential environmental hazardous chemicals. It is on the watch list of many countries, such as United States and Germany. The leaching of BPA from polycarbonate can also occur at environmental temperature and normal pH (in landfills).The amount of leaching increases as the polycarbonate parts get older. A study found that the decomposition of BPA in landfills (under anaerobic conditions) will not occur. It will therefore be persistent in landfills. Eventually, it will find its way into water bodies and contribute to aquatic pollution. In

414-482: Is also used as a printing substrate for nameplate and other forms of industrial grade under printed products. The polycarbonate provides a barrier to wear, the elements, and fading. Many polycarbonate grades are used in medical applications and comply with both ISO 10993-1 and USP Class VI standards (occasionally referred to as PC-ISO). Class VI is the most stringent of the six USP ratings. These grades can be sterilized using steam at 120 °C, gamma radiation , or by

460-466: Is an additional advantage which is that this system shows all the original architecture with elements of the new architectural concept added. Over the ceiling there is a polycarbonate cover with rounded ends, which respects the concept of the building's original project but uses more modern materials. Thermo-acoustic tiles have been instead of copper, and polycarbonate instead of glass. The trellised cover conditions 230 tons of metal structure and sustains

506-478: Is attacked by another phenoxide. The net reaction from the diphenoxide is: In this way, approximately one billion kilograms of polycarbonate is produced annually. Many other diols have been tested in place of bisphenol A, e.g. 1,1-bis(4-hydroxyphenyl)cyclohexane and dihydroxybenzophenone . The cyclohexane is used as a comonomer to suppress crystallisation tendency of the BPA-derived product. Tetrabromobisphenol A

SECTION 10

#1732877004324

552-474: Is common in the professional community. A major polycarbonate market is the production of compact discs , DVDs , and Blu-ray discs. These discs are produced by injection-molding polycarbonate into a mold cavity that has on one side a metal stamper containing a negative image of the disc data, while the other mold side is a mirrored surface. Typical products of sheet/film production include applications in advertisement (signs, displays, poster protection). In

598-474: Is common, but the use of BPA in the manufacture of polycarbonate has stirred concerns (see Potential hazards in food contact applications ), leading to development and use of "BPA-free" plastics in various formulations. Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of glass , but require much higher impact-resistance. Polycarbonate lenses also protect

644-640: Is limited to low stress applications. Stress from fasteners, plastic welding and molding render polycarbonate susceptible to stress corrosion cracking when it comes in contact with certain accelerants such as salt water and plastisol . It can be laminated to make bullet-proof "glass" , although "bullet-resistant" is more accurate for the thinner windows, such as are used in bullet-resistant windows in automobiles. The thicker barriers of transparent plastic used in teller's windows and barriers in banks are also polycarbonate. So-called "theft-proof" large plastic packaging for smaller items, which cannot be opened by hand,

690-605: Is lower as a result. The toughest grades have the highest molecular mass, but are more difficult to process. Unlike most thermoplastics, polycarbonate can undergo large plastic deformations without cracking or breaking. As a result, it can be processed and formed at room temperature using sheet metal techniques, such as bending on a brake . Even for sharp angle bends with a tight radius, heating may not be necessary. This makes it valuable in prototyping applications where transparent or electrically non-conductive parts are needed, which cannot be made from sheet metal. PMMA/Acrylic , which

736-431: Is produced by the reaction of bisphenol A (BPA) and phosgene COCl 2 . The overall reaction can be written as follows: [REDACTED] The first step of the synthesis involves treatment of bisphenol A with sodium hydroxide , which deprotonates the hydroxyl groups of the bisphenol A. The di phenoxide (Na 2 (OC 6 H 4 ) 2 CMe 2 ) reacts with phosgene to give a chloroformate , which subsequently

782-444: Is similar in appearance to polycarbonate, is brittle and cannot be bent at room temperature. Main transformation techniques for polycarbonate resins: Polycarbonate may become brittle when exposed to ionizing radiation above 25 kGy (kJ/kg). Polycarbonate is mainly used for electronic applications that capitalize on its collective safety features. A good electrical insulator with heat-resistant and flame-retardant properties, it

828-631: Is stronger and will hold up longer to extreme temperature. Thermally processed material is usually totally amorphous, and as a result is highly transparent to visible light , with better light transmission than many kinds of glass. Polycarbonate has a glass transition temperature of about 147 °C (297 °F), so it softens gradually above this point and flows above about 155 °C (311 °F). Tools must be held at high temperatures, generally above 80 °C (176 °F) to make strain-free and stress-free products. Low molecular mass grades are easier to mold than higher grades, but their strength

874-482: Is typically made from polycarbonate. The cockpit canopy of the Lockheed Martin F-22 Raptor jet fighter is fabricated from high optical quality polycarbonate. It is the largest item of its type. Polycarbonate, being a versatile material with attractive processing and physical properties, has attracted myriad smaller applications. The use of injection molded drinking bottles, glasses and food containers

920-463: Is used for opaque pieces). Standard polycarbonate resins are not suitable for long term exposure to UV radiation. To overcome this, the primary resin can have UV stabilisers added. These grades are sold as UV stabilized polycarbonate to injection moulding and extrusion companies. Other applications, including polycarbonate sheets, may have the anti-UV layer added as a special coating or a coextrusion for enhanced weathering resistance. Polycarbonate

966-675: Is used in products associated with power systems and telecommunications hardware. It can serve as a dielectric in high-stability capacitors . Commercial manufacture of polycarbonate capacitors mostly stopped after sole manufacturer Bayer AG stopped making capacitor-grade polycarbonate film at the end of 2000. The second largest consumer of polycarbonates is the construction industry, e.g. for domelights, flat or curved glazing, roofing sheets and sound walls . Polycarbonates are used to create materials used in buildings that must be durable but light. Polycarbonates are used extensively in 3D FDM printing, producing durable strong plastic products with

SECTION 20

#1732877004324

1012-568: Is used to enhance fire resistance. Tetramethylcyclobutanediol has been developed as a replacement for BPA. An alternative route to polycarbonates entails transesterification from BPA and diphenyl carbonate : Polycarbonate is a durable material. Although it has high impact-resistance, it has low scratch-resistance. Therefore, a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate compare to those of polymethyl methacrylate (PMMA, acrylic), but polycarbonate

1058-807: The Lumia series . Samsung started using polycarbonate with Galaxy S III 's hyperglaze -branded removable battery cover in 2012. This practice continues with various phones in the Galaxy series. Apple started using polycarbonate with the iPhone 5C 's unibody case in 2013. Benefits over glass and metal back covers include durability against shattering (advantage over glass), bending and scratching (advantage over metal), shock absorption, low manufacturing costs, and no interference with radio signals and wireless charging (advantage over metal). Polycarbonate back covers are available in glossy or matte surface textures . Polycarbonates were first discovered in 1898 by Alfred Einhorn ,

1104-472: The ethylene oxide (EtO) method. Trinseo strictly limits all its plastics with regard to medical applications. Aliphatic polycarbonates have been developed with improved biocompatibility and degradability for nanomedicine applications. Some smartphone manufacturers use polycarbonate. Nokia used polycarbonate in their phones starting with the N9 's unibody case in 2011. This practice continued with various phones in

1150-532: The American company Artec. Its floor space is ten thousand square meters and the ceiling is 24 meters high. The venue usually hosts classical music concerts, but on 15 January 2009 Elton John played at the main hall, in a private concert for Cruzeiro do Sul Investments Bank. The concert was attended by 1100. The 320 m platform was strategically built to offer total visibility. It has portable risers which allow choir and orchestra to alternate in mid concert, as well as

1196-531: The Greater São Paulo region. The name Julio Prestes honors an ex-railwayman who was governor of São Paulo and a presidential candidate to Brazil. The architect who planned JP, Christiano Stockler das Neves, based his project on an eclectic style, described as neo classical Louis XVI which was a reaction to the overornate baroque style. He was also clearly influenced by the old Pennsylvania station in New York, which

1242-457: The art buses and automobiles. The FEPASA line, which had become infamous for lateness & technical problems, was finally replaced by the automobile and most stations closed their doors to passenger transportation between SW towns and the state capital. From the 1980s on the Companhia de Trens Metropolitanos - CPTM - took over the line, operating only in the metropolitan area and municipalities in

1288-620: The automotive industry, injection-molded polycarbonate can produce very smooth surfaces that make it well-suited for sputter deposition or evaporation deposition of aluminium without the need for a base-coat. Decorative bezels and optical reflectors are commonly made of polycarbonate. Its low weight and high impact resistance have made polycarbonate the dominant material for automotive headlamp lenses. However, automotive headlamps require outer surface coatings because of its low scratch resistance and susceptibility to ultraviolet degradation (yellowing). The use of polycarbonate in automotive applications

1334-970: The eye from UV light. Many kinds of lenses are manufactured from polycarbonate, including automotive headlamp lenses, lighting lenses, sunglass / eyeglass lenses , camera lenses , swimming goggles and SCUBA masks, and safety glasses/goggles/visors including visors in sporting helmets/masks and police riot gear (helmet visors, riot shields, etc.). Windscreens in small motorized vehicles are commonly made of polycarbonate, such as for motorcycles, ATVs, golf carts, and small airplanes and helicopters. The light weight of polycarbonate as opposed to glass has led to development of electronic display screens that replace glass with polycarbonate, for use in mobile and portable devices. Such displays include newer e-ink and some LCD screens, though CRT, plasma screen and other LCD technologies generally still require glass for its higher melting temperature and its ability to be etched in finer detail. As more and more governments are restricting

1380-407: The façade of the building the technical and restoration teams had to spend three months researching. Using old photographs, the original mirrors and door handles were designed and then copied by craftsmen. The doors also required special care, and 81 were restored. The sandstone that was used came from the same quarry as in 1926. Shoebox style (architecture) In architecture , shoebox style

1426-481: The hall's "shoe box" shape, the specialists opted for a 150 mm slab, supported by metallic girders protected by the main structure (trusses) surrounded by 3 panels of gypsum board, each one measuring 12.5 mm thick. In addition to this, ante-chambers were built in all the circulation areas and accesses to the concert hall to exclude undesirable noises. The passage to the platforms is also protected with thick glass, and also effectively blocks invasion of noise from

Sala São Paulo - Misplaced Pages Continue

1472-568: The original brownish polycarbonate tint was improved to "glass-clear". The use of polycarbonate containers for the purpose of food storage is controversial. The basis of this controversy is their hydrolysis (degradation by water, often referred to as leaching) occurring at high temperature, releases bisphenol A : More than 100 studies have explored the bioactivity of bisphenol A derived from polycarbonates. Bisphenol A appeared to be released from polycarbonate animal cages into water at room temperature and it may have been responsible for enlargement of

1518-465: The presence of UV light, oxidation of this polymer yields compounds such as ketones, phenols, o-phenoxybenzoic acid, benzyl alcohol and other unsaturated compounds. This has been suggested through kinetic and spectral studies. The yellow color formed after long exposure to sun can also be related to further oxidation of phenolic end group This product can be further oxidized to form smaller unsaturated compounds. This can proceed via two different pathways,

1564-621: The product from the SW of São Paulo State and Parana' State to the port of Santos. The state of São Paulo acquired the EFS in 1905 and its name was changed to Ferrovia Paulista S/A or FEPASA in the 1970s. After the 1929 New York Exchange crash and recession that followed, the São Paulo coffee stock market declined in importance. With industrialization and the advent of the car industry and the excellent São Paulo State road network, mass transportation switched to state of

1610-658: The products formed depends on which mechanism takes place. Pathway A Pathway B Photo-aging is another degradation route for polycarbonates. Polycarbonate molecules (such as the aromatic ring) absorb UV radiation. This absorbed energy causes cleavage of covalent bonds which initiates the photo-aging process. The reaction can be propagated via side chain oxidation, ring oxidation or photo-Fries rearrangement . Products formed include phenyl salicylate , dihydroxybenzophenone groups, and hydroxydiphenyl ether groups. Waste polycarbonate will degrade at high temperatures to form solid, liquid and gaseous pollutants. A study showed that

1656-648: The products were about 40–50 wt.% liquid, 14–16 wt.% gases, while 34–43 wt.% remained as solid residue. Liquid products contained mainly phenol derivatives (~75wt.%) and bisphenol (~10wt.%) also present. Polycarbonate, however, can be safely used as a carbon source in the steel-making industry. Phenol derivatives are environmental pollutants, classified as volatile organic compounds (VOC). Studies show they are likely to facilitate ground level ozone formation and increase photo-chemical smog. In aquatic bodies, they can potentially accumulate in organisms. They are persistent in landfills, do not readily evaporate and would remain in

1702-452: The release of the bisphenol A from polycarbonate containers. Polycarbonate is incompatible with ammonia and acetone. Alcohol is a recommended organic solvent for cleaning grease and oils from polycarbonate. Studies have shown that at temperatures above 70 °C, and high humidity, polycarbonate will hydrolyze to bisphenol A (BPA). After about 30 days at 85 °C/96% RH, surface crystals are formed which for 70% consisted of BPA. BPA

1748-649: The reproductive organs of female mice. However, the animal cages used in the research were fabricated from industrial grade polycarbonate, rather than FDA food grade polycarbonate. An analysis of the literature on bisphenol A leachate low-dose effects by vom Saal and Hughes published in August 2005 seems to have found a suggestive correlation between the source of funding and the conclusion drawn. Industry-funded studies tend to find no significant effects whereas government-funded studies tend to find significant effects. Sodium hypochlorite bleach and other alkali cleaners catalyze

1794-437: The structure, had added to them 1000 tons of steel and 4.5 tons of sandstone. This is equal to the added weight of the concert hall ceiling, acoustic isolation, technical floor and air conditioning system. The estimate is that 15 thousand cubic meters of concrete were used, enough to build 12 12-storey buildings. The restoration process sought to retain the historic characteristics of the building. Before they could start work on

1840-405: The technical floor. It is composed of a reinforced steel deck, supported on a structural steel grid. The floor is attached to the columns to support the electromagnetic equipment for hanging the lining panels, air conditioning equipment and ducts. A superstructure was added in order to support the weight of the additions to the building. The columns which surround the old indoor garden, and support

1886-593: The traditional circular amphitheatre , arena or horseshoe shapes. This article related to an architectural style is a stub . You can help Misplaced Pages by expanding it . Polycarbonate Polycarbonates ( PC ) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded , and thermoformed . Because of these properties, polycarbonates find many applications. Polycarbonates do not have

Sala São Paulo - Misplaced Pages Continue

1932-509: The trains. The main floor has a capacity for 830 seats and 679 seats in the boxes and balconies on the mezzanine and first floor. The metal seats have ivory wood details. The material used, including the placing and the number of seats were all planned to avoid any possible interference with the flow of sound. The adjustable ceiling is suspended 25 meters above the main floor. It has 15 panels, each weighing 7.5 tons and are held by 20 cable coils. The panels can be individually controlled, allowing

1978-587: The use of glass in pubs and clubs due to the increased incidence of glassings , polycarbonate glasses are becoming popular for serving alcohol because of their strength, durability, and glass-like feel. Other miscellaneous items include durable, lightweight luggage, MP3/digital audio player cases , ocarinas , computer cases, riot shields , instrument panels, tealight candle containers and food blender jars. Many toys and hobby items are made from polycarbonate parts, like fins, gyro mounts, and flybar locks in radio-controlled helicopters , and transparent LEGO ( ABS

2024-416: The volume of the hall to be adjusted to between 12 thousand and 28 thousand cubic meters. This ensures that the intensity of any composition has its acoustic concept respected. The panels can be adjusted independently or together, through the use of computers, locks and automatic sensors. Along with the ceiling's flexibility, 26 velvet banners can hang 8 meters down, according to the vibration required. There

2070-607: Was demolished to give way to the building of the Madison Square Garden. While it was being built in the 1920s, the Grand Hall, where the concert hall is today, had a small railway in the middle of the construction work. Thus, imported material from Europe could be easily brought in. In the beginning of the 21st century, engineers working on the transformation of the Grand Hall have also had their difficulties to reconcile today's technology with historical conservation. An old train

2116-641: Was replaced with a gigantic 150 ton crane. This was the only way that the massive girders could be lifted around 25 metres, and be transformed into part of the structure that supports the adjustable ceiling over the new hall. The station's large hall was chosen because its dimensions are similar to 19th century concert halls, that is, it is shaped in the ' shoebox style ', as is the case of the halls in Boston, Vienna and Amsterdam. Sala São Paulo has 22 balconies at mezzanine and first floor levels. They have been placed between large columns and an adjustable ceiling, created by

#323676