Instruct: Given a question, retrieve relevant passages that can help answer the question.
Query: What is asbestos made of?
Fibre cement were probably amongst the latest materials on the market to have contained large quantities of asbestos. The reason is that the asbestos fibres are intimately bound to the cement matrix and were first considered to be well immobilized in the cement and less prone to be released in the environment, suspended in the air, and inhaled in the lung than in other materials or applications such as thermal insulation or flocking in which bare asbestos fibres were used. However, asbestos fibres are inevitably released during machining operations of the objects made of fibre-cement and by long-term erosion of the materials exposed to atmospheric weathering and wind when cement degrades. Occupational health concerns and the protection of workers in the fibre-cement factories have finally led to the progressive elimination of asbestos from these products. For health reasons, it is recommended that existing fibre-cement products that are in good condition are left undisturbed and possibly encapsulated, to prevent fibre release.
Documents discovered by lawyers in the 1990s revealed that in 1979 T&N were also notified of asbestos contamination in a house in Aviary Road that had once been part of the Midland Works after the city's Public Analyst found asbestos in an attic and garden, and an internal T&N memo about this stated "... presumably it is reasonable to suppose that adjoining properties might also be involved." Leeds City Council did not inform the public. T&N paid for the decontamination of the property in Aviary Road but "secured an understanding that 'any reference to the proximity of the buildings to the old JW Roberts factory will now be omitted from the Land Registry Records'" and all such references were then removed by Leeds City Council. They then began to prepare "dossiers on 'likely attackers' and journalists with a 'special interest' in asbestos." In 1992, when asked to comment about contamination in Aviary Road T&N said: "T&N has not been made aware of any evidence linking that asbestos with JW Roberts's former factory."
Taylor met with John Battle, then the Member of Parliament for Leeds West, in 1987 to present his findings, and Battle raised the matter in a House of Commons debate. Along with Leeds City Council, he called for a public inquiry into the deaths at Armley, but the incumbent Conservative government under Margaret Thatcher rejected the request, on the grounds that it "would cause needless concern, that it was impossible to discover what had happened at Roberts, and that no one could then have imagined that the dust could have harmed residents." Battle submitted to the House: "I cannot believe that those who owned and ran Roberts can have gone in and out without seeing the dust everywhere on the surrounding streets and pavements. If they knew that their workers within had to be protected from the asbestos dust, how could they have ignored the position of their neighbours who lived with that dust outside? It was not rendered neutral or innocuous as it left their premises. If they knew, why did they knowingly continue to ask not only their employees but local residents for a generation to pay the price with their lives for the profits of continued asbestos production? ...Should not the company be responsible for that deadly legacy? The Armley asbestos tragedy cannot remain private and hidden because it is not yet over."
Cast iron is made from pig iron, which is the product of smelting iron ore in a blast furnace. Cast iron can be made directly from the molten pig iron or by re-melting pig iron, often along with substantial quantities of iron, steel, limestone, carbon (coke) and taking various steps to remove undesirable contaminants. Phosphorus and sulfur may be burnt out of the molten iron, but this also burns out the carbon, which must be replaced. Depending on the application, carbon and silicon content are adjusted to the desired levels, which may be anywhere from 2–3.5% and 1–3%, respectively. If desired, other elements are then added to the melt before the final form is produced by casting.
People have been using natural organic polymers for centuries in the form of waxes and shellac, which is classified as a thermoplastic polymer. A plant polymer named cellulose provided the tensile strength for natural fibers and ropes, and by the early 19th century natural rubber was in widespread use. Polymers are the raw materials (the resins) used to make what are commonly called plastics. Plastics are the final product, created after one or more polymers or additives have been added to a resin during processing, which is then shaped into a final form. Polymers that have been around, and that are in current widespread use, include carbon-based polyethylene, polypropylene, polyvinyl chloride, polystyrene, nylons, polyesters, acrylics, polyurethane, and polycarbonates, and silicon-based silicones. Plastics are generally classified as "commodity", "specialty" and "engineering" plastics.
Until the twentieth century, the materials used for building were limited to brick, stone, timber and steel to form structures, slate and tiles for roof coverings, lead and sometimes copper for waterproofing details and decorative roofing effects. The Romans used concrete, but it was virtually unknown as a building material until the invention of reinforced concrete in 1849. Modern construction is much more complex, with walls, floors and roofs all built up from many elements to include structure, insulation and waterproofing often as separate layers or elements.
Alexander Amosu (born 21 June 1975) is a British/Nigerian luxury designer and entrepreneur. He was named by Guinness World Records for creating the world's most expensive suit. His 240,000 Pounds Diamond Encrusted BlackBerry Curve 8900 is ranked the world’s most expensive blackberry. He is also credited with producing the worlds's most expensive champagne. He has created exclusive luxury phone designs for Motorola, BlackBerry, Apple and Samsung.
Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. The common PET bottles are made of a synthetic polymer, polyethylene terephthalate. The plastic kits and covers are mostly made of synthetic polymers like polythene and tires are manufactured from Buna rubbers. However, due to the environmental issues created by these synthetic polymers which are mostly non-biodegradable and often synthesized from petroleum, alternatives like bioplastics are also being considered. They are however expensive when compared to the synthetic polymers.The eight most common types of synthetic organic polymers, which are commonly found in households are:
The production of Thai silk begins with the "Bombyx mori", a small silk worm that comes from the eggs of a silk moth. For their first year, these worms feast on the leaves of mulberry trees before building a cocoon with their spittle.
On 20 July 1982, Yorkshire Television broadcast the documentary "Alice - A Fight For Life", predominantly the story of Alice Jefferson, who had worked at the Acre Mill asbestos factory in Hebden Bridge for just nine months when she was 17 years old. Thirty years later she was diagnosed with mesothelioma and given only six months to live. The documentary was also an "exposé on the workings of the asbestos industry." Its broadcast resulted in £60 million being knocked off T&N's share price overnight, headlines in the national newspapers, and the setting up of a government enquiry. Within ten days the government had halved the legal limit for asbestos dust in the workplace. In 1988 Yorkshire Television picked up the "Yorkshire Evening Post" story and produced a second critical investigation focusing on the pattern of deaths in Armley, and contradicting the government's reasons for refusing an inquiry. Called "Too Close to Home", it was broadcast as part of the "First Tuesday" documentary series on 6 December 1988.
A screw is a type of fastener, in some ways similar to a bolt (see "Differentiation between bolt and screw" below), typically made of metal, and characterized by a helical ridge, known as a "male thread" (external thread). Screws are used to fasten materials by digging in and wedging into a material when turned, while the thread cuts grooves in the fastened material that may help pull fastened materials together and prevent pull-out. There are many screws for a variety of materials; those commonly fastened by screws include wood, sheet metal, and plastic.
PVC or polyvinyl chloride production dates back to the 19th century but began being widely used in the 1950s when companies discovered its versatility. By the 1980s, 20 companies were producing PVC. The advancements in chemical makeup made the material ideal for construction. Its low cost, durability, and processability made it a widely used product outside of construction into markets like IT, healthcare, and transportation The market for PVC extended out of construction into beauty products like aerosol hairspray. PVC was largely deemed harmless until four workers died of angiosarcoma in a PVC production factory in Louisville, Kentucky. After this, the vinyl industry developed a standard of one part per million (1ppm) as the acceptable level during the production of PVC and also removed PVC from hairspray products (award of commendation article). The Vinyl Institute claimed that only resin workers were at risk during the production and that the new (1ppm) standard protected against that.
The world's first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term 'plastics'. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger who has been called "the father of polymer chemistry" and Herman Mark, known as "the father of polymer physics".
They are also produced commercially. Simple whistles may cost less than 1 USD in bulk; expensive ones may be quite ornate. They are commonly made of plastic, aluminum, stainless steel, silver, brass, titanium, Corian, jade, buffalo horn and other materials.
The silicon content leads to a strengthening of the metal matrix. The appearance is similar to ordinary brass. Silicon tombac has good friction bearing characteristics and is corrosion resistant but is not resistant to ammonia atmosphere. The strength properties are largely retained at application temperatures up to 200 °C.
It is a special alloy in terms of the combination of casting process and casting temperature. In most cases, parts made of silicon tombac, are produced through the high pressure die casting process, which is normally specialized on metals with relatively low melting temperatures. But in this case the temperature melting range of silicon tombac is in the area of 950 to 1000 °C, which is relatively high for casting into permanent moulds. The advantage is the productivity of this highly automated casting process. The disadvantage is the temperature stress of the surface of the permanent mould, so that the lifetime of these moulds is limited.
Generally, it has been found that scaffolds that closely resemble the natural environments of the tissue being engineered are the most successful. As a result, much research has gone into investigating natural polymers that can be tailored, through processing methodology, toward specific design criteria. Chitosan is currently one of the most widely used polymers as it is very similar to naturally occurring glycosaminoglycan (GAGs) and it is degradable by human enzymes.
The stent platform itself is an expandable framework, generally with an elaborate mesh-like design to allow expansion, flexibility, and in some cases the ability to make/enlarge side openings for side vessels. The first DES were stainless steel alloys composed of iron, nickel, and chromium and were based on existing bare metal stents. These stents were hard to visualize with medical imaging, posed a risk of causing allergic responses, and were difficult to deliver, and subsequent new alloys were brought to bear, namely cobalt-chrome and platinum chrome, with improved performance. Subsequently, bioresorbable stents have been developed in which the stent itself dissolves over time. As of 2009, materials that had been explored included magnesium, polylactic acid, polycarbonate polymers, and salicylic acid polymers. Resorbable stents have held the promise of providing an acute treatment that would eventually allow the vessel to function normally, without leaving a permanent device behind.
In the same year, Dr. Julian W. Hill, another member of the Carothers team, began work again on attempting to produce a polyester with a molecular weight of above 4,000. His efforts were soon met with great success when he produced a synthetic polymer with a molecular weight of about 12,000. The high molecular weight allowed the melted polymer to be stretched out into strings of fiber. Thus was created the first synthetic silk, described by the chemists as a superpolyester.
The previous members of group 8 have relatively high melting points (Fe, 1538 °C; Ru, 2334 °C; Os, 3033 °C). Much like them, hassium is predicted to be a solid at room temperature, although the melting point of hassium has not been precisely calculated. Hassium should crystallize in the hexagonal close-packed structure (/ = 1.59), similarly to its lighter congener osmium. Pure metallic hassium is calculated to have a bulk modulus (resistance to uniform compression) comparable to that of diamond (442 GPa). Hassium is expected to have a bulk density of 40.7 g/cm, the highest of any of the 118 known elements and nearly twice the density of osmium, the most dense measured element, at 22.61 g/cm. This results from hassium's high atomic weight, the lanthanide and actinide contractions, and relativistic effects, although production of enough hassium to measure this quantity would be impractical, and the sample would quickly decay. Osmium is the densest element of the first 6 periods, and its heavier congener hassium is expected to be the densest element of the first 7 periods.
The entire monument is made of Pentelic marble, from Mt. Pentelikon, 18.2 km northeast of the arch. Pentelic marble was used for the Parthenon and many other notable structures in Athens, although its quality can vary significantly. The marble used for the arch is of a lower grade that had more inclusions than that used in the best Athenian buildings. The arch was constructed without cement or mortar from solid marble, using clamps to connect the cut stones. It is 18m high, 13.5m wide, and 2.3m in depth. Its design is fully symmetrical from front to back and side to side.
The view of most scholars (see organology) is that the term "brass instrument" should be defined by the way the sound is made, as above, and not by whether the instrument is actually made of brass. Thus one finds brass instruments made of wood, like the alphorn, the cornett, the serpent and the didgeridoo, while some woodwind instruments are made of brass, like the saxophone.
In 2000, tests in a certified asbestos-testing laboratory found the tremolite form of amphibole asbestos used to be found in three out of eight popular brands of children's crayons that were made partly from talc: Crayola, Prang, and RoseArt. In Crayola crayons, the tests found asbestos levels around 0.05% in "Carnation Pink" and 2.86% in "Orchid"; in Prang crayons, the range was from 0.3% in "Periwinkle" to 0.54% in "Yellow"; in Rose Art crayons, it was from 0.03% in "Brown" to 1.20% in "Orange". Overall, 32 different types of crayons from these brands used to contain more than trace amounts of asbestos, and eight others contained trace amounts. The Art and Creative Materials Institute, a trade association which tested the safety of crayons on behalf of the makers, initially insisted the test results must have been incorrect, although they later said they do not test for asbestos. In May 2000, Crayola said tests by Richard Lee, a materials analyst whose testimony on behalf of the asbestos industry has been accepted in lawsuits over 250 times, found its crayons tested negative for asbestos. In spite of that, in June 2000 Binney & Smith, the maker of Crayola, and the other makers agreed to stop using talc in their products, and changed their product formulations in the United States.
The use of asbestos to manufacture transite was phased out in the 1980s. Previously transite was made of cement, with varying amounts (12-50%) of asbestos fiber to provide tensile strength (similar to the steel in reinforced concrete), and other materials. It was frequently used for such purposes as furnace flues, roof shingles, siding, soffit and fascia panels, and wallboard for areas where fire retardancy is particularly important. It was also used in walk-in coolers made in large supermarkets in the 1960s, 1970s and even the 1980s. Other uses included roof drain piping, water piping, sanitary sewer drain piping, laboratory fume hood panels, ceiling tiles, landscape edging, and HVAC ducts. Because cutting, breaking, and machining asbestos-containing transite releases carcinogenic asbestos fibers into the air, its use has fallen out of favor. Despite asbestos-containing transite being phased out, it is still not banned in the United States; some 230,000 deaths have been attributed to it. Demolition of older buildings containing transite materials, particularly siding made from transite requires special precautions and disposal techniques to protect workers and the public.
Asbestos shingles are roof or wall shingles made with asbestos cement board. They often resemble slate shingles and were mass-produced during the 20th century as these were more resilient to weathering than traditional slate shingles for the reason that slate is very soft and prone to weathering. Due to health risks of asbestos products, the European Union has banned all use of asbestos, including asbestos roof shingles.
Some archaeologists believe that ancients made shrouds of asbestos, wherein they burned the bodies of their kings, in order to preserve only their ashes, and prevent them being mixed with those of wood or other combustible materials commonly used in funeral pyres. Others assert that the ancients used asbestos to make perpetual wicks for sepulchral or other lamps. A famous example is the golden lamp "asbestos lychnis", which the sculptor Callimachus made for the Erechtheion. In more recent centuries, asbestos was indeed used for this purpose. Although asbestos causes skin to itch upon contact, ancient literature indicates that it was prescribed for diseases of the skin, and particularly for the itch. It is possible that they used the term "asbestos" for soapstone, because the two terms have often been confused throughout history.