Glass and Ceramic Products |
Glass is an amorphous, non-crystaline material with various degrees of transparency. Ancient glass made from about 72% silica (quartz), which is silicon dioxide [SiO2] or "beach sand", 15% soda ash [= "soda", which is sodium carbonate, Na2CO3], 10% lime, and 3% impurities. These basic ingredients are the same today, but other elements are added to obtain special properties, depending on whether the glass is used for plates, containers (bottles, beakers, jars, bowls, drinking glasses), mirrors, and lenses (corrective "eyeglasses", microscopes, telescopes, cameras), products that affect living standards significantly. Broken glass, called cullet, is added to the mixture to hasten the melting in a furnace from 1200°F in the old furnaces to 2000°F in today's furnaces. There is a natural glass, called obsidian, formed by rocks melting and quickly cooling under high-temperate, such as occurring in a volcanic eruption. It has little commercial value. In addition to the soda-lime-silica glass (see above), which is used for containers, windows, and fibers (for fabrics and insulation), other ingredients are used to give glass special properties. Borosilicate glass has about 10% boric oxide [B2O3], which is highly resistant to thermal shock (sudden changes in temperature), is used in laboratories, cookware, pharmaceuticalware, and outdoor lighting. Solder glass, to which is added boric oxide, lead oxide, and zine oxide, is used for sealing two glass surfaces, laser glasses to host laser producing materials, safety glass, which is glass laminated with a resin to keep it from shattering, etc. Considine 1380 Plate glass used for windows contributed to living standards by allowing sunlight to enter factories and homes without resorting to the more expensive installed artificial light. An optical lens is circular-shaped glass designed to concentrate or diverge light. In its usual form, a lens consists of a slab of glass with two shaped surfaces of a particular curvature. Lenses are classified by the curvature of these two surfaces A lens works by refracting (bending) the light that passes through it. Corrective lenses enabled people with imperfect vision to read and work more efficiently. Lenses contributed to living standards by making possible the invention of the microscope, which enabled scientists to study subjects not available to the unaided eye. Advances in biology and medicine would have been impossible without the microscope. Lenses are subjects to aberrations (distortions) that need correcting. Spherical aberrations are incorrect curvatures, corrected by more accurate grinding. Chromatic aberrations (top) (false colors) are light spectrum colors that cloud the view. The invention of achromatic lenses (bottom) to correct this aberration was an important invention. Wiki n.p. All optical instruments now use achromatic lenses. Fiberglass is glass spun into fibers. Its usefulness, however, is as a composite material made from extremely fine fibers of glass. It is widely used in the manufacture of insulation and textiles. It is also used as a reinforcing agent for many plastic products, the result being a composite material called glass-reinforced plastic (GRP), also known as glass-fiber reinforced epoxy (GRE). The plastic is most often polyester, but other plastics, like epoxy (GRE), are also sometimes used. GRP/GRE is a versatile material with many uses. Its first main application was for building of boats, where it gained acceptance in the 1950s. Now, it is used extensively within the automotive and sport equipment sectors. GRE is also used to make pipes for drinking water, sewers, chemicals, and so on. Wiki n.p. Ceramics are objects made of baked clay, such as vases and other forms of pottery, tiles, small sculptures, bathtubs, washbowls, sinks, electrical insulating devices, water and sewerage pipes, bricks, hollow tile, glazed building tile, floor and wall tile, earthenware, and porcelain enamel. Ceramics have great durability, which can be divided into three types: chemical, mechanical and thermal. Ceramics are resistant to almost all acids, alkalies, and organic solvents. They are not affected by oxygen, so they will not rust. Ceramics have great strength and hardness. The compressive strengths of ceramic materials are extremely high, normally 50,000 to 100,000 lbs / sq. in. This hardness makes ceramic materials very resistant to abrasion. It is this property which makes them useful for floors, and for abrasives. Most ceramics can withstand high temperatures. Therefore, they are useful in the production of all types of heat-containing equipment such as kilns for the ceramic industry, and such products as the inner linings of fireplaces and home heating furnaces. Bedrosians n.p. From glassmaking, an ancient industry, came the invention of convex lenses for eyeglasses (spectacles) in the 13th century. Concave lenses were invented in the 15th century, so that now bifocal spectacles were available. In 1590, the Dutch spectacle-maker, Zacharias Janssen invented the microscope ("Janssen's tube"), which eventually was used by scientists to study microorganisms to revolutionize biology and medicine. Asimov 141 In 1688, in France, large sheets of cheap plate glass were made for the first time, which could be used for windows and mirrors. Its use expanded so that homes could allow sunlight to enter while keeping out prevent dirt, wind, rain, and cold air, thus improving the living standards of many people. Asimov 195 A chromatic lens produces colors at the focus that blurs the object image. An achromatic lens for the telescope was invented in 1733 by Chester Hall, an English mathematician. He achieved this by combining a convex lens made from ordinary window glass ("crown glass") and a concave lens made from flint glass, which contains lead. This biconvex (convex on both sides) lens produced an achromatic lens because the spreading of the colors by the crown glass was balanced by the condensing of the colors by the flint glass. Since Hall did not publish his invention, John Dollond, who invented the same lens in 1757, is usually given the credit. Asimov 213 In 1739, Caspar Wistar, of Salem County, NJ, built a large glass factory in Allowaytown. He used skilled workers from Germany to produce fine glassware. In 1740, Wistar opened a glass factory to produce window and bottle glass. It employed skilled workers from Belgium. It operated as a worker cooperative, one of the first in the colonies. Schles 86 An achromatic lens is a combination of two or more lenses made of different types of glass that correct each other for achromatic aberration. These are called apochromatic or process lenses. In 1758, John Dolland, made the first achromatic lens. How 8 In 1769, Henry William Stiegel started a glass factory in Mannheim, PA. His glassware becomes reknown for its artistry. Schles 109 The first mechanical pressing of glass was made in 1825. This was the first instance of mass-production in the glass industry. For centuries prior to that time, glass was blown. Cheap glassware appeared in stores for the first time. Deming Jarvis of Sandwich, MA, was a company famous for its large-scale production of pressed glass that operated until 1888. Around the same time, reflecting and achromatic telescopes were made in Southwick, MA, for the first time. Carruth 173 In 1830, the British optician, Joseph Lister, invented an achromatic microscope. It extended the effective area of the microscope and enabled the use of lenses of shorter focal point. For example, bacteria could only be studied effectively with an achromatic lens. Asimov 325 Glassmakers throughout history had experimented with glass fibers, but innovations such as fiberglass were only made possible with the advent of finer machine-tooling. In 1893, Edward Drummond Libbey exhibited a dress at the World Columbian Exposition incorporating glass fibers with the diameter and texture of silk fibers. Wiki n.p. What is commonly known as "fiberglass" today was invented in 1938 by Russell Games Slayter of Owens-Corning as a material to be used as insulation. It is marketed under the trade name Fiberglas. Wiki n.p. |