Telecommunication is the transmission of signs, messages, writings and sounds or information of any nature by wire, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology, it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is used in its plural form because it involves many different technologies. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, optical heliographs. Other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, loud whistles. 20th- and 21st-century technologies for long-distance communication involve electrical and electromagnetic technologies, such as telegraph and teleprinter, radio, microwave transmission, fiber optics, communications satellites.
A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse, Alexander Graham Bell, Edwin Armstrong and Lee de Forest, as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth; the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, the Latin communicare, meaning to share. Its modern use is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié. Communication was first used as an English word in the late 14th century, it comes from Old French comunicacion, from Latin communicationem, noun of action from past participle stem of communicare "to share, divide out.
Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots, was used by the Romans to aid their military. Frontinus said; the Greeks conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Sumatra, and in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, chains of beacons were used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London. In 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris.
However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres. As a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. On 25 July 1837 the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke, English scientist Sir Charles Wheatstone. Both inventors viewed their device as "an improvement to the electromagnetic telegraph" not as a new device. Samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837, his code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was completed on 27 July 1866, allowing transatlantic telecommunication for the first time; the conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849.
However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. Starting in 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using the newly discovered phenomenon of radio waves, showing by 1901 that they could be transmitted across the Atlantic Ocean; this was the start of wireless telegraphy by radio. Voice and music had little early success. World War I accelerated the development of radio for military communications. After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated development of radio for the wartime purposes of aircraft and land communication, radio navigation and radar. Development of stereo FM broadcasting of radio
Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction and convection. The terms radiant heating and radiant cooling are used to describe this approach because radiation is responsible for a significant portion of the resulting thermal comfort but this usage is technically correct only when radiation composes more than 50% of the heat exchange between the floor and the rest of the space. Underfloor heating has a long history back into the Neolithic periods. Archeological digs in Asia and the Aleutian islands of Alaska reveal how the inhabitants drafted smoke from fires through stone covered trenches which were excavated in the floors of their subterranean dwellings; the hot smoke heated the floor stones and the heat radiated into the living spaces. These early forms have evolved into modern systems using fluid filled pipes or electrical cables and mats. Below is a chronological overview of under floor heating from around the world.
Modern underfloor heating systems use either electrical resistance elements or fluid flowing in pipes to heat the floor. Either type can be installed as the primary, whole-building heating system or as localized floor heating for thermal comfort; some systems allow for single rooms to be heated when they are a part of a larger multi-room system, avoiding any wasted heat. Electrical resistance can only be used for heating. Other applications for which either electric or hydronic systems are suited include snow/ice melting for walks and landing pads, turf conditioning of football and soccer fields and frost prevention in freezers and skating rinks. A range of underfloor heating systems and designs are available to suit different types of flooring. Electric heating elements or hydronic piping can be cast in a concrete floor slab, they can be placed under the floor covering or attached directly to a wood sub floor. Some commercial buildings are designed to take advantage of thermal mass, heated or cooled during off peak hours when utility rates are lower.
With the heating/cooling system turned off during the day, the concrete mass and room temperature drift up or down within the desired comfort range. Such systems are known as thermally activated building systems or TABS. Hydronic systems use water or a mix of water and anti-freeze such as propylene glycol as the heat transfer fluid in a "closed loop", recirculated between the floor and the boiler. Various types of pipes are available for hydronic underfloor heating and cooling systems and are made from polyethylene including PEX, PEX-Al-PEX and PERT. Older materials such as Polybutylene and copper or steel pipe are still used in some locales or for specialized applications. Hydronic systems require skilled designers and tradespeople familiar with boilers, controls, fluid pressures and temperature; the use of modern factory assembled sub-stations, used in district heating and cooling, can simplify design requirements and reduce the installation and commissioning time of hydronic systems. Hydronic systems can use a single source or combination of energy sources to help manage energy costs.
Hydronic system energy source options are: Boilers including Combined heat and power plants heated by: Natural gas or "methane" industry-wide is considered the cleanest and most efficient method of heating water, depending on availability. Costs about $7/million b.t.u. Propane made from oil, less efficient than natural gas by volume, much more expensive on a b.t.u. basis. Produces more carbon dioxide than "methane" on a b.t.u. basis. Costs about $25/million b.t.u. Coal, oil, or waste oil Electricity Solar thermal Wood or other biomass Bio-fuels Heat pumps and chillers powered by: Electricity Natural gas Geothermal heat pump Electric systems are used only for heating and employ non-corrosive, flexible heating elements including cables, pre-formed cable mats, bronze mesh, carbon films. Due to their low profile they can be installed in a thermal mass or directly under floor finishes. Electric systems can take advantage of time-of-use electricity metering and are used as carpet heaters, portable under area rug heaters, under laminate floor heaters, under tile heating, under wood floor heating, floor warming systems, including under shower floor and seat heating.
Large electric systems require skilled designers and tradespeople but this is less so for small floor warming systems. Electric systems use fewer components and are simpler to install and commission than hydronic systems; some electric systems use line voltage technology. Power consumption of an electric system is not based on voltage but rather wattage output produced by the heating element; as defined by ANSI/ASHRAE Standard 55 – Thermal Environmental Conditions for Human Occupancy, thermal comfort is, "that condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation." Relating to underfloor heating, thermal comfort is influenced by floor surface temperature and associated elements such as radiant asymmetry, mean radiant temperature and operative temperature. Research by Nevins, Gagge, P. Ole Fanger et al. show that humans at rest with clothing typical of light office and home wear, exchange over 50% of their sensible heat via radiation.
Underfloor heating influences the radiant exchange by warming the interior surfaces. The heating of the surfaces suppresses body heat loss resulting
A balcony is a platform projecting from the wall of a building, supported by columns or console brackets, enclosed with a balustrade above the ground floor. The traditional Maltese balcony is a wooden closed balcony projecting from a wall. By contrast, a'Juliet balcony' does not protrude out of the building, it is part of an upper floor, with a balustrade only at the front, like a small Loggia. Modern Juliet balconies involve a metal barrier placed in front of a high window which can be opened. Juliet balconies are named after Shakespeare's Juliet, who, in traditional stagings of the play Romeo and Juliet, is courted by Romeo while she is on her balcony—though the play itself, as written, makes no mention of a balcony, but only of a window at which Juliet appears. Various types of balcony have been used in depicting this famous scene; the Julian Balcony is a larger version of the well-known Juliet Balcony, protruding from the wall, unlike the smaller Juliet balcony, spanning at least two windows rather than one.
Sometimes balconies are adapted for ceremonial purposes, e.g. that of St. Peter's Basilica at Rome, when the newly elected pope gives his blessing urbi et orbi after the conclave. Inside churches, balconies are sometimes provided for the singers, in banqueting halls and the like for the musicians. A unit with a regular balcony will have doors that open up onto a small patio with railings, a small Patio garden or Skyrise greenery. A French balcony is a false balcony, with doors that open to a railing with a view of the courtyard or the surrounding scenery below. In theatres, the balcony was a stage-box, but the name is now confined to the part of the auditorium above the dress circle and below the gallery. Balconies are part of the sculptural shape of the building allowing for irregular facades without the cost of irregular internal structures. One of the most famous uses of a balcony is in traditional stagings of the scene that has come to be known as the "balcony scene" in William Shakespeare's tragedy and Juliet.
Manufacturers' names for their balcony designs refer to the origin of the design, e.g. Italian balcony, Spanish balcony, Mexican balcony, Ecuadorian balcony, they refer to the shape and form of the pickets used for the balcony railings, e.g. knuckle balcony. Deck Jharokha Loggia Mashrabiya Mezzanine Minstrel's gallery Patio Porch Verandah Balconing Media related to Balconies at Wikimedia Commons "Balcony". Encyclopædia Britannica. 1911
A raised floor provides an elevated structural floor above a solid substrate to create a hidden void for the passage of mechanical and electrical services. Raised floors are used in modern office buildings, in specialized areas such as command centers, Information technology data centers and computer rooms, where there is a requirement to route mechanical services and cables and electrical supply; such flooring can be installed at varying heights from 2 inches to heights above 4 feet to suit services that may be accommodated beneath. Additional structural support and lighting are provided when a floor is raised enough for a person to crawl or walk beneath. In the U. S. underfloor air distribution is becoming a more common way to cool a building by using the void below the raised floor as a plenum chamber to distribute conditioned air, done in Europe since the 1970s. In data centers, isolated air-conditioning zones are associated with raised floors. Perforated tiles are traditionally placed beneath computer systems to direct conditioned air directly to them.
In turn, the computing equipment is designed to draw cooling air from below and exhaust into the room. An air conditioning unit draws air from the room, cools it, forces it beneath the raised floor, completing the cycle; this type of floor consists of a gridded metal framework or substructure of adjustable-height supports that provide support for removable floor panels, which are 2×2 feet or 60×60 cm. The height of the legs/pedestals is dictated by the volume of cables and other services provided beneath, but arranged for a clearance of at least six inches or 15 cm with typical heights between 24 inches to 48 inches; the panels are made of steel-clad particleboard or a steel panel with a cementitious internal core, although some tiles have hollow cores. Panels may be covered with a variety of flooring finishes to suit the application, such as carpet tiles, high-pressure laminates, marble and antistatic finishes for use in computer rooms and laboratories; when using a panel with a cement top surface the panels are sometimes left bare and sealed or stained and sealed to create a tile appearance and save the customer money.
This bare application is used most in office area, lobbies, casinos, etc. Many modern computer and equipment rooms employ an underfloor air distribution to ensure cooling of the room with minimal wasted energy. Conditioned air is provided under the floor and dispersed upward into the room through spaced diffuser tiles, blowers or through ducts directed into specific equipment. Automatic fire protection shutoffs may be required for underfloor ventilation, additional suppression systems may be installed in case of underfloor fires. Many office buildings now use access flooring to create more sustainable spaces. A large corporation can have over 20,000 miles of cabling in a single facility; when underfloor air is designed into a building from the start of the project, the building can be less expensive to build and less expensive to operate over the life of the building. Underfloor air requires less space per floor, thereby reducing the overall height of the building, which in turn reduces the cost of the building facade.
The blowers and air handlers required for underfloor air are much smaller and require less energy, since hot air rises through the space as it comes in contact with people and equipment that warm the air and it rises to the ceiling. Additionally, when buildings are designed to combine modular electrical, modular walls, access floor, the space within the building can be reconfigured in a few hours, as compared to historical means of demolishing walls and drilling holes in the floor to route electrical and other services; as more companies construct or renovate buildings to meet LEED underfloor air and access floor usage will continue to grow. The USGBC states. While major wiring may not be the focus, residential use of raised floors and split levels in 12 foot ceiling Manhattan apartments provides "high-performance elements" and added functionality. To remove panels, a tool with a suction cup on the end is used. A hook-and-loop lifter may be used on carpeted panels. Structural problems, such as rocking panels and gaps between panels, can cause significant damage to equipment and injury to personnel.
Regular inspections for the structural integrity of a raised floor system can help to identify and mitigate problems. Equipment and floor damage can happen. Load ratings range from 1,000 pounds to 25,000 pounds. Higher panels can be used on heavier areas of a floor whereas lower panels can be used on lighter areas. Many such problems can be attributed to sub-par installation. During installation, attention should be paid to the condition of the subfloor, which should be clean of debris and should be as level as possible; the walls surrounding the raised floor should be as square as possible to minimize the need for cutting raised floor panels and to minimize rocking panels and gaps. Because the flooring tiles are removed once equipment has been installed, the space below them is cleaned, fluff and other debris settles, making working on cabling underneath the flooring a dirty job. Smoke detectors under the raised floor can be triggered by workers disturbing the dust, resulting in false alarms.
A ceiling is an overhead interior surface that covers the upper limits of a room. It is not considered a structural element, but a finished surface concealing the underside of the roof structure or the floor of a story above. Ceilings can be decorated to taste, there are many fine examples of frescoes and artwork on ceilings in religious buildings; the most common type of ceiling is the dropped ceiling, suspended from structural elements above. Panels of drywall are fastened either directly to the ceiling joists or to a few layers of moisture-proof plywood which are attached to the joists. Pipework or ducts can be run in the gap above the ceiling, insulation and fireproofing material can be placed here. A subset of the dropped ceiling is the suspended ceiling, wherein a network of aluminum struts, as opposed to drywall, are attached to the joists, forming a series of rectangular spaces. Individual pieces of cardboard are placed inside the bottom of those spaces so that the outer side of the cardboard, interspersed with aluminum rails, is seen as the ceiling from below.
This makes it easy to repair the pipes and insulation behind the ceiling, since all, necessary is to lift off the cardboard, rather than digging through the drywall and replacing it. Other types of ceiling include the cathedral ceiling, the concave or barrel-shaped ceiling, the stretched ceiling and the coffered ceiling. Coving links the ceiling to the surrounding walls. Ceilings can play a part in reducing fire hazard, a system is available for rating the fire resistance of dropped ceilings. Ceilings are classified according to their construction. A cathedral ceiling is any tall ceiling area similar to those in a church. A dropped ceiling is one in which the finished surface is constructed anywhere from a few inches or centimeters to several feet or a few meters below the structure above it; this may be done such as achieving a desirable ceiling height. An inverse of this would be a raised floor. A concave or barrel-shaped ceiling is curved or rounded upward for visual or acoustical value, while a coffered ceiling is divided into a grid of recessed square or octagonal panels called a "lacunar ceiling".
A cove ceiling uses a curved plaster transition between ceiling. A stretched ceiling uses a number of individual panels using material such as PVC fixed to a perimeter rail. Ceilings have been decorated with fresco painting, mosaic tiles and other surface treatments. While hard to execute a decorated ceiling has the advantage that it is protected from damage by fingers and dust. In the past, this was more than compensated for by the damage from smoke from candles or a fireplace. Many historic buildings have celebrated ceilings; the most famous is the Sistine Chapel ceiling by Michelangelo. Ceiling height may have psychological impacts; the most common ceiling that contributes to fire-resistance ratings in commercial and residential construction is the dropped ceiling. In the case of a dropped ceiling, the rating is achieved by the entire system, both the structure above, from which the ceilings is suspended, which could be a concrete floor or a timber floor, as well as the suspension mechanism and the lowest membrane or dropped ceiling.
Between the structure that the dropped ceiling is suspended from and the dropped membrane, such as a T-bar ceiling or a layer of drywall, there is some room for mechanical and electrical piping and ducting to run. An independent ceiling, can be constructed such that it has a stand-alone fire-resistance rating; such systems must be tested without the benefit of being suspended from a slab above in order to prove that the resulting system is capable of holding itself up. This type of ceiling would be installed to protect items above from fire. Beam ceiling Hammerbeam roof Hollow-core slab Moulding Popcorn ceiling Scottish Renaissance painted ceilings Tin ceiling Passive fire protection Fire test Hy-Rib Media related to Ceilings at Wikimedia Commons "Ceiling". Encyclopædia Britannica. 5. 1911. "Ceiling". New International Encyclopedia. 1904. Merriam-Webster ceiling definition False Ceiling Latest Design Diydata.com treatise on lath & plasterboard ceilings Virtualmuseum.ca treatise on ceiling construction
Glass floors are made with transparent glass when it is useful to view something from above or below. In either case, toughened glass is chosen, for its durability and resistance to breakage. Translucent floors are sometimes set into outdoor sidewalks and pavements, or the floors of well-lit interior spaces, to daylight the space below; these are called pavement lights, have a long history. Glass as a flooring material is used in both commercial structures. Special hollow glass blocks known as'"glass pavers" are used in combination with a metal frame. Glass floors are lit from below with natural or artificial light, or may be treated as ordinary floor surfaces illuminated from above. A German manufacturer of squash court floors has diversified into making glass floors for other sports, such as basketball, their glass floors are translucent rather than transparent, the line markings are indicated by illumination with LEDs below the floor. On occasion, transparent display cases are built into the floor, such as in the Museum of Sydney, where the remains of drains and privies are shown in their original context, along with other archeological artifacts.
Made of a toughened glass, laminated for structural strength, a transparent floor is most used as a tourist attraction. Glass-bottom boats are popular for allowing a better view into the water. At 4000 feet, the highest glass floor above ground is the novel outdoor application of the Grand Canyon Skywalk, operated by the Hualapai Indian tribe; the highest above ground level in a freestanding structure is in the CN Tower in Toronto, Ontario at 1122 feet. In May 2014, the top layer of a glass floor spontaneously shattered in "the Ledge", a popular tourist attraction more than 1,500 feet above street level, near the top of the Willis Tower in Chicago. Spokespersons for the architect and the tower management said that the broken glass was a protective layer, that two other slabs of glass beneath it were strong enough to prevent anybody falling through; some new planetariums now feature a glass floor, which allows spectators to stand near the center of a sphere surrounded by projected images in all directions, giving the impression of floating in outer space.
For example, a small planetarium at AHHAA in Tartu, Estonia features such an installation, with special projectors for images below the feet of the audience, as well as above their heads. Scientific studies of locomotion and gait have used glass floors to enable views from all angles. Glass floors have been used by artists to study foreshortening; the surrealist painter Salvador Dalí had one built to help him with the dramatic perspectives in his artwork. Glass Floor Heliobus Applications of glass flooring
Nightingale floors listen, are floors that make a chirping sound when walked upon. These floors were used in the hallways of some temples and palaces, the most famous example being Nijō Castle, in Kyoto, Japan. Dry boards creak under pressure, but these floors were built in a way that the flooring nails rub against a jacket or clamp, causing chirping noises, it is unclear. It seems that, at least the effect arose by chance. An information sign in Nijō castle states that "The singing sound is not intentional, stemming rather from the movement of nails against clumps in the floor caused by wear and tear over the years". Legend has it that the squeaking floors were used as a security device, assuring that none could sneak through the corridors undetected; the English name "nightingale" refers to the Japanese bush warbler, or uguisu, a type of bushtit or nightingale native to Japan. The floors were made from dried boards. Upside-down V-shaped joints move within the boards. Uguisu refers to the Japanese bush-warbler.
The latter segment bari comes from haru, meaning "to stretch". Together this means "the sound of a Nightingale from the stretching/swelling/straining "; the following locations incorporate nightingale floors: Nijō Castle, Kyoto Chion-in, Kyoto Eikan-dō Zenrin-ji, Kyoto Daikaku-ji, Kyoto Melody Road in Hokkaido and Gunma Singing Road in Anyanag, Gyeonggi South Korea Civic Musical Road in Lancaster, California A-Z Animals. "Uguisi" under "Animals".. Accessed November 3, 2012. Http://a-z-animals.com/animals/uguisu/. Bunt and Gillian Hall, ed. Oxford Beginner's Japanese Dictionary. New York: Oxford University Press, 2000. Henshall, Kenneth G. A Guide to Remembering Japanese Characters. Vermont: Tuttle Publishing Company, 1998. Japan-guide.com. "Nijo Castle" under "Kyoto Travel: Nijo Castle". Accessed November 3, 2012. Http://www.japan-guide.com/e/e3918.html. Saiga-Jp.com. "Japanese Kanji Dictionary" under "Japanese Learning". Accessed November 4, 2012. Https://web.archive.org/web/20101029180930/http://www.saiga-jp.com/kanji_dictionary.html.
ZenGarden.org. "Nightingale Floor,'Uguisu-bari'". Accessed September 24, 2012. Http://www.zen-garden.org/html/page_nightingalefloor.htm. Information and video-clip of Nightingale floors Kyoto Travel: Nijo Castle