An exit sign is a device in a public facility denoting the location of the closest emergency exit in case of fire or other emergency. Most relevant codes require exit signs to be permanently lit. Exit signs are designed to be unmistakable and understandable to anyone. In the past, this meant exit signs that show the word "EXIT" or the equivalent in the local language, but exit signs around the world are in pictogram form, with or without supplementary text. Early exit signs were either made of metal and lit by a nearby incandescent light bulb or were a white glass cover with "EXIT" written in red, placed directly in front of a single-bulb light fixture. An inherent flaw with these designs was that in a fire, the power to the light failed. In addition, the fixtures could be difficult to see in a fire where smoke reduced visibility, despite being bright; the biggest problem was that the exit sign was hardly distinguishable from an ordinary safety lighting fixture installed above doors in the past.
The problem was solved by using red-tinted globes instead. Better signs were soon developed that more resembled today's modern exit sign, with an incandescent bulb inside a rectangular-shaped box that backlit the word "EXIT" on one or both sides. Being larger than its predecessors, this version of the exit sign solved some of the visibility problems; the sign was only useful as long. As battery-backup systems became smaller and more efficient, some exit signs began to use a dual-power system. Under normal conditions, the exit sign was lit by mains power and the battery was in a charged state. In the event of a power outage, the battery would supply power to light the sign. Early battery-backup systems were big and costly. Modern systems are lightweight, can be installed anywhere, are integrated into the fixture, rather than requiring a separate box; as batteries improved, so did the amount of time that a fixture could remain lit on batteries. While exit signs were more visible due to large letters a 60-watt incandescent bulb shining through a plastic or glass cover could appear somewhat dim under certain conditions.
Incandescent bulbs are still in use because they are cheap and common though they use more electricity and require more or less frequent replacement. Incandescent bulbs lit 24/7 have a extended lifespan compared to ones that cycle on and off; when used in exit signs, they are operated at a lower voltage than rated, which further extends their lifetime, at the tradeoff of reduced light output and reduced energy efficiency. With the development of fluorescent lamp and light-emitting diode technology, exit signs could be made brighter to compensate for the limited visibility in a fire situation, while using less electricity. Fluorescent lamps work in the same way as incandescent bulbs, back-lighting both sides of an exit fixture from within. LED signs combine a large number of bright light-emitting diodes to illuminate the sign from inside. An exit sign is lit. LEDs have a long life, may last for 10 years or more of continuous use, although their brightness may diminish. Radioluminescent and phosphorescent signs that require no electricity have been developed, have been used since the 1970s.
Radioluminescence uses the radioactive decay of tritium gas to illuminate the sign, while phosphorescence uses light-emitting phosphors to glow in the dark. While both of these signs meet California State Fire Marshal standards, electricity is used in the vast majority of signs. Most exit signs in the world, except in countries such as the US, Hong Kong and Singapore, are of pictogram type. Australia and Hong Kong have made changes to their respective life safety codes to encourage pictogram use. In the US, regulations require text based exit signs for all standard mounted applications. However, globalization has led to limited adoption of the ISO pictogram in the US. For example, the NFPA has approved the ISO pictogram as an option for low level glow-in-the-dark signs. New York City local law 26 requires these low level symbolic signs in all high rise buildings. In tunnels, the Transportation Research Board recommends using the ISO symbol. Newer Airbus, Bombardier CS100 and Boeing 787 Dreamliner planes started using the new pictogram exit signs, which were approved by the FAA in 2012 and 2014.
Modern exit signs can be seen indicating the path to an exit in commercial and large residential buildings that comply with fire code. Certain circumstances, such as the year a building was built, may leave it exempt from some of these codes. In most situations, the owner of the building is responsible for complying with exit sign requirements; this is true in older buildings that serve as multiple residences, such as apartment buildings and campus dormitories. Modern signs can adopt active and/or dissuasive signage solutions. Modern fixtures are in a rugged plastic or metal housing securely bolted to the wall or ceiling; the signs have a picture representing exit, on both sides. Single-sided signs are available for wall-mount installations; the signs have metal or plastic knock-outs which can be removed so that an arrow is lit pointing left or right. Modern exit signs are combined with other safety devices, such as emergency floodlighting for supplementary area illumination. Exit signs draw a
A balanced-arm lamp, sometimes called a floating arm lamp, is a lamp with an adjustable folding arm, constructed so that the force due to gravity is always counteracted by springs, regardless of the position of the arms of the lamp. Many lamp brands as well as other devices, such as drawing boards, use this principle. A balanced-arm lamp has a base, two connected arms fitted with springs, a lamp-head; the lamp can be moved into any position, the springs will maintain the position until moved again. The same mechanism can be employed in other devices with similar requirements, such as copy holders for typists and some computer display holders; this article uses the terminology lamp cap, upper arm and base for the four basic parts of these lamps. For the physics and theory behind balanced-arm lamps, see Classical mechanics and torque. There are different methods to balance the lamp-cap of a balanced-arm lamp; some lamps have two coil springs working in parallel on both sides of the pivoting arm.
Others are balanced with counterweights. Friction between parts of the lamp arm can be used to maintain balance. There are a number of mechanical solutions which have been used for balanced-arm lamps. There are many variations of construction with springs. Springs can be located on the mechanical equivalent of the forearm or the upper arm, or both, as well as nearer the base; some lamps use tension springs, others use compression springs. The adjacent image shows a compression spring at rest under load, followed by a tension spring at rest, under load. Springs have a limited lifting extension length; some springs can resonate. Spring-balanced upper arm, flexible forearm This lamp has a stiff flexible tube as its forearm, a spring-balanced arm to support it near the middle; that way there is a flexible lamp with a long reach. Tension spring over wheels The wheel to control the forearm is smaller than the wheel that controls the upper arm; the lamp cap rotates the same direction as forearm. Two arms, one spring, one toothed wheel With this technique the tension spring has a double function: it controls both the forearm and the upper arm.
This is not a common arm lamp system. The lamp cap rotates the same direction as forearm. Two parallelograms and two tension spring sets One tension spring set controls the forearm, a parallelogram having two bars. A stronger spring set controls the upper arm. Due to the parallel linkage of the lamp, the lamp cap keeps pointing in the same vertical direction when adjusting the height of the lamp; as with most balanced-arm lamps, the whole assembly can rotate in the horizontal plane, is mounted on a stable foot. One parallelogram and two extension spring sets A lamp like the Anglepoise lamp has one parallelogram and two extension springs. One spring controls the shortest arm of a parallelogram. Parallel to this shortest arm there is the forearm. To keep these arms parallel there are two other parallel arms that are controlled by a second extension spring; the lamp cap rotates the same direction as forearm. Single forearm bar, one parallelogram, two tension spring sets The forearm of this lamp consist of a single bar.
When it is adjusted, the angle of the lamp cap changes along with the arm. Tension springs within the arms A lamp like the Tolomeo desk lamp has no parallelograms in either arm. In this modern lamp the tension springs are hidden in the arms; the lamp cap rotates the same direction as forearm. Compression springs in the arms The short arms stay parallel. One spring puts pull force on the blue arm; the blue arm controls the two parallel arms. The other spring puts pull force on the other blue arm; this arm controls the forearm. The two springs can be the same size; the other spring is more horizontal. Compression springs near the foot One compression spring controls a short arm; the Roller chain cable connects this arm parallel to the forearm. The longer spring controls the arm; the body can turn in the horizontal plane. The body is connected to a stable foot; the body can be smaller. A compression spring with one parallelogram In this method, just one compression spring controls a pantographic arm. Pressure and friction lamps This construction is quite common in Italian lamps.
Gravity causes the parallelogram to deform, making the gap between the long arms smaller. This increases pressure on the rubber in the gap, the resulting friction holds the arm in balance. An advantages of one swinging counterbalance is. Disadvantages are that the stand is less stable, the lamp needs a heavy foot to stand stable. A single counterweight This construction uses a chain to keep the arm with the counterweight and the forearm parallel; the lamp-cap and counterweight move in opposite directions. The balance, required is shown by the following formula: d1 = Lamp-cap to base.
A nightlight is a small light fixture electrical, placed for comfort or convenience in dark areas or areas that may become dark at certain times, such as at night or in an emergency. Small long-burning candles serving a similar function are referred to as "tealights". People use nightlights for the sense of security which having a light on provides, or to relieve fear of the dark in young children. Nightlights are useful to the general public by revealing the general layout of a room without requiring a major light to be switched on, for avoiding tripping over stairs, obstacles, or pets, or to mark an emergency exit. Exit signs use tritium in the form of a traser. Homeowners place nightlights in bathrooms and hallways to avoid turning on the main light fixture late at night, causing their eyes to adjust to the brighter light; some frequent travelers carry small nightlights for temporary installation in their guestroom and bathroom, to avoid tripping or falls in an unfamiliar nighttime environment.
Gerontologists have recommended use of nightlights to prevent falls, which can be life-threatening to the elderly. The low cost of nightlights has enabled a proliferation of different decorative designs, some featuring superheros and fantastical designs, while others feature the basic simplicity of a small luminous disc. Early electrical nightlights used small incandescent lamps or small neon lamps to provide light, were much safer than small candles using an open flame; the neon versions consumed little energy and had a long life, but had a tendency to flicker on and off, which some users liked and others found annoying. In the 1960s, small nightlights appeared that featured a low-power electroluminescent panel emitting soft green or blue light; some nightlights include a photocell, which enables them to switch off when the ambient light is sufficiently bright. Other designs feature a built-in passive infrared sensor to detect motion, only switch on when somebody is passing by in the dark. With the availability of low-cost LEDs, many different variants have become available, featuring different colours, sometimes changing automatically or in a user-controllable way.
The US Consumer Product Safety Commission reports it receives about 10 reports per year where nightlights close to flammable materials were cited as responsible for fires. A University of Pennsylvania study indicated that sleeping with the light on or with a nightlight was associated with a greater incidence of nearsightedness in children. However, a study at Ohio State University contradicted the earlier conclusion. Both studies were published in the journal Nature. Another study has indicated that sleeping with the light on may protect the eyes of diabetics from retinopathy, a condition that can lead to blindness. However, the initial study is still inconclusive; the optimal sleeping light condition is said by some to be total darkness. If a nightlight is used within a sleeping area, it is recommended to choose a dim reddish light to minimize disruptive effects on sleep cycles. In addition, nightlights may be useful in locations other than sleeping areas, such as hallways, bathrooms, or kitchens, to allow late night trips to be made without turning on the full light, while preserving a dark sleeping environment.
Lamp shade LED lamp Light-emitting diode The dictionary definition of nightlight at Wiktionary
A Tiffany lamp is a type of lamp with a glass shade made with glass designed by Louis Comfort Tiffany and his design studio. The most famous was the stained leaded glass lamp. Tiffany lamps are considered part of the Art Nouveau movement. Due to Tiffany's dominant influence on the style, the term'Tiffany lamp' or'Tiffany style lamp' has been used to refer to stained leaded glass lamps those not made by Louis Comfort Tiffany's company; the first Tiffany lamp was created around 1895. Each lamp was handmade by skilled craftsmen, not mass- or machine-produced, its designer was not, as had been thought for over 100 years, Louis Comfort Tiffany, but a unrecognized artist named Clara Driscoll, identified in 2007 by Rutgers professor Martin Eidelberg as being the master designer behind the most creative and valuable leaded glass lamps produced by Tiffany Studios. Tiffany's first business venture was an interior design firm in New York City, for which he designed stained glass windows. Tiffany lamps gained popularity after the Worlds Columbian Exposition in Chicago in 1893, where Tiffany displayed his lamps in a Byzantine-like chapel.
His presentation caught the eye of many people, most notably Wilhelm Bode and Julius Lessing, directors of state museums in Berlin. Lessing purchased a few pieces to display in the Museum of Decorative Arts, making it the first European museum to own Tiffany glass. Though Tiffany's work was popular in Germany, other countries, such as France, were not as taken by it because of its relation to American crafts. Tiffany was only able to break into the French market by having the production of his works taken over by Siegfried Bing, with the assistance of many French artists. Without Bing’s access and contacts in Europe, Tiffany would not have had as much success selling his works to a European audience. Tiffany’s success throughout Europe was due to the success of his works in the German and Austro-Hungarian markets through a series of exhibitions beginning in 1897 at the International Art Exhibition in Dresden. After the partnership between Tiffany and Bing ended, interest in Tiffany products began to decline in Europe.
Most of Tiffany's lamps can be grouped into one of seven categories: Irregular upper border Irregular lower border Favrile Geometric Transition to flowers Flowered cone Flowered globeThe Irregular Upper and Lower Border lamps carry an openwork crown edge that helps to simulate a branch, tree, or shrubbery. The Favrile category, which means handcrafted, identifies the first lamps Tiffany made with this label, his initials LCT replaced the Favrile stamp. The Geometric category, done by the male craftsman, speaks for itself; the Tiffany craftsman used geometric shapes such as triangles, squares and ovals to form these patterns for these lamps. Next is the Transition to Flowers group, subdivided into the Flowered Cone and Globe lamps. All of these lamps follow a nature, or botanical, design using flowers, spiders with webs and peacock feathers; the difference within these two smaller categories is the difference in the lamp shapes a cone and a globe. Every lamp is prepared by using the copper foil method.
First a pattern for the lamp is drawn out on a heavy piece of cardboard. Next a number and glass color is written on the pattern piece. After the pattern is drawn and labeled, the glass traced. Once the pattern is traced onto the glass, the pieces can ground to their correct shape. Next the pieces need to be cleaned; the copper foil solution allows the pieces to adhere together. After the lamp has been placed accordingly and it is bonded, the edges need to be soldered together for a firm hold. After the lamp has been soldered it is cleaned to bring out its beauty. New York Historical Society, Central Park West at West 77th Street – 132 lamps in the Dr. Egon Neustadt Collection of Tiffany Glass Queens Museum of Art, Flushing Meadows Corona Park, New York – the remainder of Neustadt's collection, which went to the museum after his death Virginia Museum of Fine Arts, Virginia – 14 lamps on display in the Lewis Decorative Arts Galleries, with an additional four lamps in museum's collection but not on display Clara Driscoll Tiffany glass The dictionary definition of Appendix:Tiffany lamps at Wiktionary
A gooseneck lamp is a type of light fixture in which a lamp or lightbulb is attached to a flexible, adjustable shaft to allow the user to position the light source without moving the fixture or item to be illuminated. Gooseneck lamps are used to position a light for reading, or in industry, to provide spot illumination for machining operations; these lamps can come in any color. Gooseneck lamps may be free standing floor lamps, desk lamps, or have magnetic bases in industrial applications. Balanced-arm lamp
A factory or manufacturing plant is an industrial site consisting of buildings and machinery, or more a complex having several buildings, where workers manufacture goods or operate machines processing one product into another. Factories arose with the introduction of machinery during the Industrial Revolution when the capital and space requirements became too great for cottage industry or workshops. Early factories that contained small amounts of machinery, such as one or two spinning mules, fewer than a dozen workers have been called "glorified workshops". Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production. Large factories tend to be located with access to multiple modes of transportation, with some having rail and water loading and unloading facilities. Factories may either make discrete products or some type of material continuously produced such as chemicals and paper, or refined oil products. Factories manufacturing chemicals are called plants and may have most of their equipment – tanks, pressure vessels, chemical reactors and piping – outdoors and operated from control rooms.
Oil refineries have most of their equipment outdoors. Discrete products may be final consumer goods, or parts and sub-assemblies which are made into final products elsewhere. Factories may make them from raw materials. Continuous production industries use heat or electricity to transform streams of raw materials into finished products; the term mill referred to the milling of grain, which used natural resources such as water or wind power until those were displaced by steam power in the 19th century. Because many processes like spinning and weaving, iron rolling, paper manufacturing were powered by water, the term survives as in steel mill, paper mill, etc. Max Weber considered production during ancient times as never warranting classification as factories, with methods of production and the contemporary economic situation incomparable to modern or pre-modern developments of industry. In ancient times, the earliest production limited to the household, developed into a separate endeavour independent to the place of inhabitation with production at that time only beginning to be characteristic of industry, termed as "unfree shop industry", a situation caused under the reign of the Egyptian pharaoh, with slave employment and no differentiation of skills within the slave group comparable to modern definitions as division of labour.
According to translations of Demosthenes and Herodotus, Naucratis was a, or the only, factory in the entirety of ancient Egypt. A source of 1983, states the largest factory production in ancient times was of 120 slaves within 4th century BC Athens. An article within the New York Times article dated 13 October 2011 states: "In African Cave, Signs of an Ancient Paint Factory" –... discovered at Blombos Cave, a cave on the south coast of South Africa where 100,000-year-old tools and ingredients were found with which early modern humans mixed an ochre-based paint. Although The Cambridge Online Dictionary definition of factory states: a building or set of buildings where large amounts of goods are made using machines elsewhere:... the utilization of machines presupposes social cooperation and the division of labour The first machine is stated by one source to have been traps used to assist with the capturing of animals, corresponding to the machine as a mechanism operating independently or with little force by interaction from a human, with a capacity for use with operation the same on every occasion of functioning.
The wheel was invented c. 3000 BC, the spoked wheel c. 2000 BC. The Iron Age began 1200–1000 BC. However, other sources define machinery as a means of production. Archaeology provides a date for the earliest city as 5000 BC as Tell Brak, therefore a date for cooperation and factors of demand, by an increased community size and population to make something like factory level production a conceivable necessity. According to one text the water-mill was first made in 555 A. D. by Belisarius, although according to another they were known to Pliny the Elder and Vitruvius in the first century B. C. By the time of the 4th century A. D. mills with a capacity to grind 3 tonnes of cereal an hour, a rate sufficient to meet the needs of 80,000 persons, were in use by the Roman Empire. The Venice Arsenal provides one of the first examples of a factory in the modern sense of the word. Founded in 1104 in Venice, Republic of Venice, several hundred years before the Industrial Revolution, it mass-produced ships on assembly lines using manufactured parts.
The Venice Arsenal produced nearly one ship every day and, at its height, employed 16,000 people. One of the earliest factories was John Lombe's water-powered silk mill at Derby, operational by 1721. By 1746, an integrated brass mill was working at Warmley near Bristol. Raw material went in at one end, was smelted into brass and was turned into pans, pins and other goods. Housing was provided for workers on site. Josiah Wedgwood in Staffordshire and Matthew Boulton at his Soho Manufactory were other prominent early industrialists, who employed the factory system; the factory system began widespread use somewhat when cotton spinning was mechanized. Richard Arkwright is the person credited with inventing the prototype of the modern factory. After he patented his water frame in 1769, he established Cromford Mill, in Derbyshire, England expanding the village of Cromford to accommodate the migrant workers new to the area; the factory system was a new way of organizing labour made necessary by the developm
Incandescent light bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light. The filament is protected from oxidation with a glass or fused quartz bulb, filled with inert gas or a vacuum. In a halogen lamp, filament evaporation is slowed by a chemical process that redeposits metal vapor onto the filament, thereby extending its life; the light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, work well on either alternating current or direct current; as a result, the incandescent bulb is used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, flashlights, for decorative and advertising lighting.
Incandescent bulbs are much less efficient than other types of electric lighting. The remaining energy is converted into heat; the luminous efficacy of a typical incandescent bulb for 120 V operation is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps. Some applications of the incandescent bulb deliberately use the heat generated by the filament; such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, the Easy-Bake Oven toy. Incandescent bulbs have short lifetimes compared with other types of lighting. Incandescent bulbs have been replaced in many applications by other types of electric light, such as fluorescent lamps, compact fluorescent lamps, cold cathode fluorescent lamps, high-intensity discharge lamps, light-emitting diode lamps; some jurisdictions, such as the European Union, China and United States, are in the process of phasing out the use of incandescent light bulbs while others, including Colombia, Cuba and Brazil, have prohibited them already.
In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance that made power distribution from a centralized source economically viable. Historian Thomas Hughes has attributed Edison's success to his development of an entire, integrated system of electric lighting; the lamp was a small component in his system of electric lighting, no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, the parallel-distribution system. Other inventors with generators and incandescent lamps, with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting.
In 1761 Ebenezer Kinnersley demonstrated heating a wire to incandescence. In 1802, Humphry Davy used what he described as "a battery of immense size", consisting of 2,000 cells housed in the basement of the Royal Institution of Great Britain, to create an incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an high melting point, it was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Over the first three-quarters of the 19th century, many experimenters worked with various combinations of platinum or iridium wires, carbon rods, evacuated or semi-evacuated enclosures. Many of these devices were demonstrated and some were patented. In 1835, James Bowman Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland, he stated that he could "read a book at a distance of one and a half feet". Lindsay, a lecturer at the Watt Institution in Dundee, Scotland, at the time, had developed a light, not combustible, created no smoke or smell and was less expensive to produce than Davy's platinum-dependent bulb.
However, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented, although he is credited in Challoner et al. with being the inventor of the "Incandescent Light Bulb". In 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament. In 1840, British scientist Warren de la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it; the design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although a workable design, the cost of the platinum made it impractical for commercial use. In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using platinum wires contained within a vacuum