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Rhoca-Gil
{{unreferenced, date=December 2013 Rhoca-Gil is a type of industrial sealant produced by Rhône-Poulenc, used in the construction of tunnels to block the passage of groundwater into the tunnel. The sealant begins as a liquid, is then injected into cavities which need to be sealed, and polymerises, causing it to harden. Process Rhoca-Gil consists of two fluids, that are mixed, thinned out with water and then sprayed into cracks in the bedrock. One of the fluids contains acrylamide and methylolacrylamide. The mixed solution becomes a viscous fluid that penetrates cracks and holes in the rock, where the fluid reacts— polymerizes—to a tight plastic substance. When it is completely polymerized it is stable and will not exhaust any toxic compounds. Controversies In 1992 construction of the Hallandsås tunnel in Sweden began, with opening plans for 1995. Groundwater leaking into the tunnel was however a major problem, slowing the progress, and Rhoca-Gil was used. In 1997, fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallandsås Tunnel
The Hallandsås Tunnel ( sv, Hallandsåstunneln), also known as the Hallandsås Ridge Tunnel or Scanlink, is a railway tunnel in Sweden. It connects the northern and the southern sides of the Hallandsås geological formation (a horst). The length is ( in one bore, in the other). It's utilised by the West Coast Line, on the section between Ängelholm and Halmstad in southwestern Sweden. It has improved the connection between the cities of Gothenburg, Sweden, and Copenhagen, Denmark. In the longer term it will be a key component in the proposed Oslo to Hamburg high speed rail link via Gothenburg, Malmö and Copenhagen. The project was troubled by construction difficulties caused by groundwater ingress, and a scandal when dangerous sealant materials were used causing workers to become ill and killing local fish and cattle. These caused the project to be halted from late 1997 to 2005, and resulted in large cost over-runs. The project was finished in December 2015, over 23 yea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhône-Poulenc
Rhône-Poulenc () was a French chemical and pharmaceutical company founded in 1928. In 1999 it merged with Hoechst AG to form Aventis. As of 2015, the pharmaceutical operations of Rhône-Poulenc are part of Sanofi and the chemicals divisions are part of Solvay group and Bayer Crop Science. History The company was founded in 1928 through the merger of Société des usines chimiques du Rhône (Society of Rhône Chemical Factories) from Lyon and Poulenc Frères (Poulenc Brothers) from Paris founded by Étienne Poulenc, a 19th-century Parisian apothecary and brought to prominence by his second and third sons Émile, father of composer Francis Poulenc, and Camille Poulenc (1864–1942). In 1950, the company synthesized chlorpromazine which it sold to Smith, Kline & French (today part of GlaxoSmithKline) who marketed the drug as Thorazine. In 1990, it merged with the pharmaceutical company Rorer to form Rhône-Poulenc Rorer. In January 1999, Rhône-Poulenc merged with Hoechst AG to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gardermobanen
The Gardermoen Line ( no, Gardermobanen) is a high-speed railway line between Oslo and Eidsvoll, Norway, running past Lillestrøm and Oslo Airport, Gardermoen. The line is long and replaced the older Hoved Line as the main line north-east of Oslo. The older Hoved Line now handles commuter and freight traffic, while the Gardermoen Line handles high-speed passenger trains and freight trains laden with jet fuel for the airport. Both lines are owned by Bane NOR. The line was opened in 1998, at the same time as the airport that gave the line its name. It is used by the Flytoget airport express train service as well as express trains by Vy. It is the only high-speed railway in Norway, with a maximum permitted speed of . Most of the line between Oslo and Lillestrøm is through the Romeriksporten tunnel—the second longest railway tunnel in Norway. The decision to build the line was made in 1992; construction started two years later. The line was subjected to severe criticism during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sealant
Sealant is a substance used to block the passage of fluids through openings in materials, a type of mechanical seal. In building construction ''sealant'' is sometimes synonymous with ''caulking'' and also serve the purposes of blocking dust, sound and heat transmission. Sealants may be weak or strong, flexible or rigid, permanent or temporary. Sealants are not adhesives but some have adhesive qualities and are called ''adhesive-sealants'' or ''structural sealants''. History Sealants were first used in prehistory in the broadest sense as mud, grass and reeds to seal dwellings from the weather such as the daub in wattle and daub and thatching. Natural sealants and adhesive-sealants included plant resins such as pine pitch and birch pitch, bitumen, wax, tar, natural gum, clay (mud) mortar, lime mortar, lead, blood and egg. In the 17th century glazing putty was first used to seal window glass made with linseed oil and chalk, later other drying oils were also used to make oil-bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer, monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple free-radical reaction, radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. Alkanes can also be polymerized, but only with the help of strong acids. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylamide
Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2. It is a white odorless solid, soluble in water and several organic solvents. From the chemistry perspective, acrylamide is a vinyl-substituted primary amide (CONH2). It is produced industrially mainly as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. Acrylamide forms in burnt areas of food, particularly starchy foods like potatoes, when cooked with high heat, above . Acrylamide is highly toxic, linked to cancer in animal testing though not likely to be carcinogenic for humans, but its main derivative polyacrylamide is nontoxic. The possibility that this innocuous polymer contains traces of its hazardous precursor has long attracted attention. Because acrylamide is volatile and hazardous, it is mainly handled as an aqueous solution. Production Acrylamide can be prepared by the hydration of acrylonitrile: :CH2=CHCN + H2O → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, Finland to the east, and is connected to Denmark in the southwest by a bridgetunnel across the Öresund. At , Sweden is the largest Nordic country, the third-largest country in the European Union, and the fifth-largest country in Europe. The capital and largest city is Stockholm. Sweden has a total population of 10.5 million, and a low population density of , with around 87% of Swedes residing in urban areas in the central and southern half of the country. Sweden has a nature dominated by forests and a large amount of lakes, including some of the largest in Europe. Many long rivers run from the Scandes range through the landscape, primarily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise from both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious. Carcinogens, as mentioned, are agents in the environment capable of contributing to cancer growth. Carcinogens can be categorized into two different types: activation-dependent and activation-independent, and each nature impacts their level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutagen
In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer in animals, such mutagens can therefore be carcinogens, although not all necessarily are. All mutagens have characteristic mutational signatures with some chemicals becoming mutagenic through cellular processes. The process of DNA becoming modified is called mutagenesis. Not all mutations are caused by mutagens: so-called "spontaneous mutations" occur due to spontaneous hydrolysis, DNA error, errors in DNA replication, repair and Genetic recombination, recombination. Discovery The first mutagens to be identified were carcinogens, substances that were shown to be linked to cancer. Tumors were described more than 2,000 years before the discovery of chromosomes and DNA; in 500 B.C., the Greece, Greek physician Hippocrates named tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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