Frequently Asked Questions (FAQ) for Decorative Light Manufactures

Pottery was produced in enormous quantities in ancient Rome, mostly for utilitarian purposes. It is found all over the former Roman Empire and beyond. Monte Testaccio is a huge waste mound in Rome made almost entirely of broken amphorae used for transporting and storing liquids and other products - in this case probably mostly Spanish olive oil, which was landed nearby (and was the main fuel for lighting, as well as its use in the kitchen and baths). It is usual to divide Roman domestic pottery broadly into coarse wares and fine wares, the former being the everyday pottery jars, dishes and bowls that were used for cooking or the storage and transport of foods and other goods, and in some cases also as tableware, and which were often made and bought locally. Fine wares were serving vessels or tableware used for more formal dining, and are usually of more decorative and elegant appearance. Some of the most important of these were made at specialised pottery workshops, and were often traded over substantial distances, not only within, but also between, different provinces of the Roman Empire. For example, dozens of different types of British coarse and fine wares were produced locally, yet many other classes of pottery were also imported from elsewhere in the Empire. The manufacture of fine wares such as terra sigillata took place in large workshop complexes that were organised along industrial lines and produced highly standardised products that lend themselves well to precise and systematic classification. There is no direct Roman equivalent to the artistically central vase-painting of Ancient Greece, and few objects of outstanding artistic interest have survived, but there is a great deal of fine tableware, and very many small figures, often incorporated into oil lamps or similar objects, and often with religious or erotic themes. Roman burial customs varied over time and space, so vessels deposited as grave goods, the usual source of complete ancient pottery vessels, are not always abundant, though all Roman sites produce plenty of broken potsherds. "Fine" rather than luxury pottery is the main strength of Roman pottery, unlike Roman glass, which the elite often used alongside gold or silver tableware, and which could be extremely extravagant and expensive. It is clear from the quantities found that fine pottery was used very widely in both social and geographic terms. The more expensive pottery tended to use relief decoration, usually moulded, rather than colour, and often copied shapes and decoration from the more prestigious metalwork. Especially in the Eastern Empire, local traditions continued, hybridizing with Roman styles to varying extents. From the 3rd century the quality of fine pottery steadily declined, partly because of economic and political disturbances, and because glassware was replacing pottery for drinking cups (the rich had always preferred silver in any case). Fired clay or terracotta was also widely employed in the Roman period for architectural purposes, as structural bricks and tiles, and occasionally as architectural decoration, and for the manufacture of small statuettes and lamps. These are not normally classified under the heading pottery by archaeologists, but the terracottas and lamps will be included in this article. Pottery is a key material in the dating and interpretation of archaeological sites from the Neolithic period onwards, and has been minutely studied by archaeologists for generations. In the Roman period, ceramics were produced and used in enormous quantities, and the literature on the subject, in numerous languages, is very extensive.

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2. what are the uses of a ruby gem?

Natural rubies are found in a handful of sites around the world, most notably in Myanmar (formerly Burma), Thailand, Sri Lanka, Afghanistan, Tanganyika, and North Carolina. Beautifully colored, transparent crystals are prized for jewelry use, while translucent or opaque stones are used for ornamental items such as clock bases. In addition to their decorative functions, rubies serve a broad range of utilitarian purposes. For example, because of their hardness, they make long-lasting thread guides for textile machines. Ruby is even harder than steel, so it is an excellent bearing material for metal shafts in devices like watches, compasses, and electric meters. Rubies have exceptional wave-transmitting properties for the range from short, ultraviolet wavelengths through the visible light spectrum to long, infrared wavelengths. This makes them ideal for use in lasers and masers (laser-like devices operating in non-visible ranges of microwaves and radio waves). Because many of these industrial uses demand very high-quality crystals of particular sizes and shapes, synthetic rubies are manufactured. With the exception of minor amounts of impurities, synthetic gems have the same chemical, physical, and optical properties as their natural counterparts. Although some are used as gemstones, about 75% of modern synthetic ruby production is used for industrial purposes. Several methods are currently used to manufacture rubies; each has advantages and limitations. The most popular methods can be categorized into two main types: production from melt, in which powdered material is heated to a molten state and manipulated to solidify in a crystalline form, and production from "solution," in which the required aluminum oxide and chromium are dissolved in another material and manipulated to precipitate into a crystalline form. Verneuil's flame fusion and Czochralski's crystal pulling are the most commonly used melt techniques, while flux growth and hydrothermal growth are the most popular versions of solution processes. Flame fusion rubies, generally the least expensive, are commonly used for bearings and relatively mundane jewelry like class rings. Pulled rubies, selling for upwards of $5 per carat, are preferred for laser use. Flux rubies, costing $50 or more per carat, are used in finer jewelry. The less-common hydrothermal process is used for industrial applications demanding strain-free crystals or large crystals in something other than a rod shape.

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3. What for we use mercury?

Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some thermometers, especially ones which are used to measure high temperatures (In the United States, non-prescription sale of mercury fever thermometers is banned by a number of different states and localities). Other uses: Mercury sphygmomanometers. Mercury barometers, diffusion pumps, coulometers, and many other laboratory instruments. As an opaque liquid with a high density and a nearly linear thermal expansion, it is ideal for this role. The triple point of mercury, -38.8344 C, is a fixed point used as a temperature standard for the International Temperature Scale (ITS-90). In some gaseous electron tubes, mercury arc rectifier Gaseous mercury is used in mercury-vapour lamps and some "neon sign" type advertising signs and fluorescent lamps. Liquid mercury was sometimes used as a coolant for nuclear reactors; however, sodium is proposed for reactors cooled with liquid metal, because the high density of mercury requires much more energy to circulate as coolant. Mercury was once used in the amalgamation process of refining gold and silver ores. This polluting practice is still used by the garimpeiros (gold miners) of the Amazon basin in Brasil. Mercury is still used in some cultures for folk medicine and ceremonial purposes which may involve ingestion, injection, or the sprinkling of elemental mercury around the home. It must be emphasized that the former two procedures, especially, are extremely hazardous and the latter is nearly as so because mercury spreads easily and is therefore ingested. Alexander Calder built a mercury fountain for the Spanish Pavilion at the 1937 World's Fair in Paris. The fountain is now on display at the Fundaci Mir in Barcelona. Used in electrochemistry as part of a secondary reference electrode called the calomel electrode as an alternative to the Standard Hydrogen Electrode. This is used to work out the electrode potential of half cells. Used in Cold Cathode (also generalised under the Neon Sign Industry) lighting to increase the success of ionization and conductivity in Argon filled lamps, an Argon filled lamp without Mercury will have dull spots and will fail to light correctly. Lighting containing Mercury can only be bombarded/oven pumped once. When added to Neon filled tubes the light produced will be inconsistent red/blue spots until the initial burning-in process is completed; eventually it will light a consistent dull off-blue colour. Mercury was once used as a gun barrel bore cleaner. Miscellaneous uses: mercury switches (including home Mercury Light Switches installed prior to 1970), tilt switches used in old fire detectors, tilt switches in many modern home thermostats, electrodes in some types of electrolysis, batteries (mercury cells, including for sodium hydroxide and chlorine production, handheld games, and alkaline batteries), catalysts, insecticides, dental amalgams/preparations and liquid mirror telescopes. Thiomersal, (called Thimerosal in the United States), an organic compound used as a preservative in vaccines, though this use is in decline. Historical uses: preserving wood, developing daguerreotypes, silvering mirrors, anti-fouling paints (discontinued in 1990), herbicides (discontinued in 1995), handheld maze games, cleaning, and road levelling devices in cars. Mercury compounds have been used in antiseptics, laxatives, antidepressants, and in antisyphilitics. It was also allegedly used by allied spies to sabotage German planes. A mercury paste was applied to bare aluminium, causing the metal to rapidly corrode. This would cause mysterious structural failures. In Islamic Spain it was used for filling decorative pools. In some applications, mercury can be replaced with less toxic but considerably more expensive galinstan alloy. A new type of atomic clock, using mercury instead of caesium, has been demonstrated. Accuracy is expected to be within one second in 100 million years.

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4. What are some uses for sulfur?

In the late 1700s, furniture makers used molten sulfur to produce decorative inlays in their craft. Because of the sulfur dioxide produced during the process of melting sulfur, the craft of sulfur inlays was soon abandoned. Molten sulfur is sometimes still used for setting steel bolts into drilled concrete holes where high shock resistance is desired for floor-mounted equipment attachment points. Pure powdered sulfur was also used as a medicinal tonic and laxative. Sulfur has many modern industrial uses. Through its major derivative, sulfuric acid (H2SO4), sulfur ranks as one of the most important industrial raw materials. It is of prime importance to every sector of the world's economies. Sulfuric acid production is the major route in industrial sulfur chemistry on the way to many end-uses, and production and consumption of sulfuric acid has been regarded as one of the best indices of a nation's industrial development. . For example, more sulfuric acid is produced in the United States every year than any other industrial chemical; although interestingly the rate of increase of U.S. production has encountered shocks since the mid 1960's, mirroring U.S. loss of industrial post-World War II world influence. Principal uses for the acid include ore processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis. Sulfur is also used in batteries, detergents, the vulcanization of rubber, fungicides, ie skin care soaps, and in the manufacture of phosphate fertilizers. Sulfites are used to bleach paper and as a preservative in wine and dried fruit. Because of its flammable nature, sulfur also finds use in matches, gunpowder, and fireworks. Sodium or ammonium thiosulfate is used as photographic fixing agents. Magnesium sulfate, better known as Epsom salts, can be used as a laxative, a bath additive, an exfoliant, a magnesium supplement for plants, or a dessicant. Sulfur is used as a light-generating medium in the rare lighting fixtures known as sulfur lamps. Elemental sulfur crystals are commonly sought after by rock collectors for their brightly colored polyhedron shapes. editBiological role