Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared or visible light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances.

Optical fiber is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals. Researchers at Bell Labs have reached a record bandwidth–distance product of over  kilometers per second using fiber-optic communication.

Background
First developed in the 1970s, fiber-optics have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age. Because of its advantages over electrical transmission, optical fibers have largely replaced copper wire communications in backbone networks in the developed world.

The process of communicating using fiber optics involves the following basic steps:
 creating the optical signal involving the use of a transmitter, usually from an electrical signal
 relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak
 receiving the optical signal
 converting it into an electrical signal

Applications
Optical fiber is used by telecommunications companies to transmit telephone signals, Internet communication and cable television signals. It is also used in other industries, including medical, defense, government, industrial and commercial. In addition to serving the purposes of telecommunications, it is used as light guides, for imaging tools, lasers, hydrophones for seismic waves, SONAR, and as sensors to measure pressure and temperature.

Due to lower attenuation and interference, optical fiber has advantages over copper wire in long-distance, high-bandwidth applications. However, infrastructure development within cities is relatively difficult and time-consuming, and fiber-optic systems can be complex and expensive to install and operate. Due to these difficulties, early fiber-optic communication systems were primarily installed in long-distance applications, where they can be used to their full transmission capacity, offsetting the increased cost. The prices of fiber-optic communications have dropped considerably since 2000.

The price for rolling out fiber to homes has currently become more cost-effective than that of rolling out a copper-based network. Prices have dropped to $850 per subscriber in the US and lower in countries like The Netherlands, where digging costs are low and housing density is high.

Since 1990, when optical-amplification systems became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines. By 2002, an intercontinental network of 250,000 km of submarine communications cable with a capacity of 2.56 Tb/s was completed, and although specific network capacities are privileged information, telecommunications investment reports indicate that network capacity has increased dramatically since 2004. As of 2020, over 5 billion kilometers of fiber-optic cable has been deployed around the globe.

History

In 1880 Alexander Graham Bell and his assistant Charles Sumner Tainter created a very early precursor to fiber-optic communications, the Photophone, at Bell's newly established Volta Laboratory in Washington, D.C. Bell considered it his most important invention. The device allowed for the transmission of sound on a beam of light. On June 3, 1880, Bell conducted the world's first wireless telephone transmission between two buildings, some 213 meters apart. Due to its use of an atmospheric transmission medium, the Photophone would not prove practical until advances in laser and optical fiber technologies permitted the secure transport of light. The Photophone's first practical use came in military communication systems many decades later.

In 1954 Harold Hopkins and Narinder Singh Kapany showed that rolled fiber glass allowed light to be transmitted. Jun-ichi Nishizawa, a Japanese scientist at Tohoku University, proposed the use of optical fibers for communications in 1963. Nishizawa invented the PIN diode and the static induction transistor, both of which contributed to the development of optical fiber communications.

In 1966 Charles K. Kao and George Hockham at Standard Telecommunication Laboratories showed that the losses of 1,000 dB/km in existing glass (compared to 5–10 dB/km in coaxial cable) were due to contaminants which could potentially be removed.

Optical fiber with attenuation low enough for communication purposes (about 20 dB/km) was developed in 1970 by Corning Glass Works. At the same time, GaAs semiconductor lasers were developed that were compact and therefore suitable for transmitting light through fiber optic cables for long distances.

In 1973, Optelecom, Inc., co-founded by the inventor of the laser, Gordon Gould, received a contract from ARPA for one of the first optical communication systems. Developed for Army Missile Command in Huntsville, Alabama, the system was intended to allow a short-range missile with video processing to communicate by laser to the ground by means of a five-kilometer long optical fiber that unspooled from the missile as it flew. Optelecom then delivered the first commercial optical communications system to Chevron.

After a period of research starting from 1975, the first commercial fiber-optic telecommunications system was developed which operated at a wavelength around 0.8 μm and used GaAs semiconductor lasers. This first-generation system operated at a bit rate of 45 Mbit/s with repeater spacing of up to 10 km. Soon on 22 April 1977, General Telephone and Electronics sent the first live telephone traffic through fiber optics at a 6 Mbit/s throughput in Long Beach, California.

In October 1973, Corning Glass signed a development contract with CSELT and Pirelli aimed to test fiber optics in an urban environment: in September 1977, the second cable in this test series, named COS-2, was experimentally deployed in two lines (9 km) in Turin, for the first time in a big city, at a speed of 140 Mbit/s.

The second generation of fiber-optic communication was developed for commercial use in the early 1980s, operated at 1.3 μm and used InGaAsP semiconductor lasers. These early systems were initially limited by multi-mode fiber dispersion, and in 1981 the single-mode fiber was revealed to greatly improve system performance, however practical connectors capable of working with single mode fiber proved difficult to develop. Canadian service provider SaskTel had completed construction of what was then the world's longest commercial fiber optic network, which covered  and linked 52 communities. By 1987, these systems were operating at bit rates of up to  with repeater spacing up to .

The first transatlantic telephone cable to use optical fiber was TAT-8, based on Desurvire optimized laser amplification technology. It went into operation in 1988.

Third-generation fiber-optic systems operated at 1.55 μm and had losses of about 0.2 dB/km. This development was spurred by the discovery of indium gallium arsenide and the development of the indium gallium arsenide photodiode by Pearsall. Engineers overcame earlier difficulties with pulse-spreading using conventional InGaAsP semiconductor lasers at that wavelength by using dispersion-shifted fibers designed to have minimal dispersion at 1.55 μm or by limiting the laser spectrum to a single longitudinal mode. These developments eventually allowed third-generation systems to operate commercially at  with repeater spacing in excess of .

The fourth generation of fiber-optic communication systems used optical amplification to reduce the need for repeaters and wavelength-division multiplexing (WDM) to increase data capacity. The introduction of WDM was the start of optical networking, as WDM became the technology of choice for fiber-optic bandwidth expansion. The first to market with a dense WDM system was Ciena Corp., in June 1996. The introduction of optical amplifiers and WDM caused system capacity to double every six months from 1992 until a bit rate of  was reached by 2001. In 2006 a bit-rate of  was reached over a single  line using optical amplifiers. , Japanese scientists transmitted 319 terabits per second over 3,000 kilometers with four-core fiber cables with standard cable diameter.

The focus of development for the fifth generation of fiber-optic communications is on extending the wavelength range over which a WDM system can operate. The conventional wavelength window, known as the C band, covers the wavelength range 1525–1565 nm, and dry fiber has a low-loss window promising an extension of that range to 1300–1650 nm. Other developments include the concept of optical solitons, pulses that preserve their shape by counteracting the effects of dispersion with the nonlinear effects of the fiber by using pulses of a specific shape.

In the late 1990s through 2000, industry promoters, and research companies such as KMI, and RHK predicted massive increases in demand for communications bandwidth due to increased use of the Internet, and commercialization of various bandwidth-intensive consumer services, such as video on demand. Internet Protocol data traffic was increasing exponentially, at a faster rate than integrated circuit complexity had increased under Moore's Law. From the bust of the dot-com bubble through 2006, however, the main trend in the industry has been consolidation of firms and offshoring of manufacturing to reduce costs. Companies such as Verizon and AT&T have taken advantage of fiber-optic communications to deliver a variety of high-throughput data and broadband services to consumers' homes.

Technology
Modern fiber-optic communication systems generally include optical transmitters that convert electrical signals into optical signals, optical fiber cables to carry the signal, optical amplifiers, and optical receivers to convert the signal back into an electrical signal. The information transmitted is typically digital information generated by computers or telephone systems.

Transmitters

The most commonly used optical transmitters are semiconductor devices such as light-emitting diodes (LEDs) and laser diodes. The difference between LEDs and laser diodes is that LEDs produce incoherent light, while laser diodes produce coherent light. For use in optical communications, semiconductor optical transmitters must be designed to be compact, efficient and reliable, while operating in an optimal wavelength range and directly modulated at high frequencies.

In its simplest form, an LED emits light through spontaneous emission, a phenomenon referred to as electroluminescence. The emitted light is incoherent with a relatively wide spectral width of 30–60 nm. The large spectrum width of LEDs is subject to higher fiber dispersion, considerably limiting their bit rate-distance product (a common measure of usefulness). LEDs are suitable primarily for local-area-network applications with bit rates of 10–100 Mbit/s and transmission distances of a few kilometers.

LED light transmission is inefficient, with only about 1% of input power, or about 100 microwatts, eventually converted into launched power coupled into the optical fiber.

LEDs have been developed that use several quantum wells to emit light at different wavelengths over a broad spectrum and are currently in use for local-area wavelength-division multiplexing (WDM) applications.

LEDs have been largely superseded by vertical-cavity surface-emitting laser (VCSEL) devices, which offer improved speed, power and spectral properties, at a similar cost. However, due to their relatively simple design, LEDs are very useful for very low-cost applications. Commonly used classes of semiconductor laser transmitters used in fiber optics include VCSEL, Fabry–Pérot and distributed-feedback laser.

A semiconductor laser emits light through stimulated emission rather than spontaneous emission, which results in high output power (~100 mW) as well as other benefits related to the nature of coherent light. The output of a laser is relatively directional, allowing high coupling efficiency (~50%) into single-mode fiber. Common VCSEL devices also couple well to multimode fiber. The narrow spectral width also allows for high bit rates since it reduces the effect of chromatic dispersion. Furthermore, semiconductor lasers can be modulated directly at high frequencies because of short recombination time.

Laser diodes are often directly modulated, that is the light output is controlled by a current applied directly to the device. For very high data rates or very long distance links, a laser source may be operated continuous wave, and the light modulated by an external device, an optical modulator, such as an electro-absorption modulator or Mach–Zehnder interferometer. External modulation increases the achievable link distance by eliminating laser chirp, which broadens the linewidth in directly modulated lasers, increasing the chromatic dispersion in the fiber. For very high bandwidth efficiency, coherent modulation can be used to vary the phase of the light in addition to the amplitude, enabling the use of QPSK, QAM, and OFDM. "Dual-polarization quadrature phase shift keying is a modulation format that effectively sends four times as much information as traditional optical transmissions of the same speed."

Receivers
The main component of an optical receiver is a photodetector which converts light into electricity using the photoelectric effect. The primary photodetectors for telecommunications are made from Indium gallium arsenide. The photodetector is typically a semiconductor-based photodiode. Several types of photodiodes include p-n photodiodes, p-i-n photodiodes, and avalanche photodiodes. Metal-semiconductor-metal (MSM) photodetectors are also used due to their suitability for circuit integration in regenerators and wavelength-division multiplexers.

Since light may be attenuated and distorted while passing through the fiber, photodetectors are typically coupled with a transimpedance amplifier and a limiting amplifier to produce a digital signal in the electrical domain recovered from the incoming optical signal. Further signal processing such as clock recovery from data performed by a phase-locked loop may also be applied before the data is passed on.

Coherent receivers use a local oscillator laser in combination with a pair of hybrid couplers and four photodetectors per polarization, followed by high-speed ADCs and digital signal processing to recover data modulated with QPSK, QAM, or OFDM.

Digital predistortion
An optical communication system transmitter consists of a digital-to-analog converter (DAC), a driver amplifier and a Mach–Zehnder modulator. The deployment of higher modulation formats (>4-QAM) or higher baud Rates (>) diminishes the system performance due to linear and non-linear transmitter effects. These effects can be categorized as linear distortions due to DAC bandwidth limitation and transmitter I/Q skew as well as non-linear effects caused by gain saturation in the driver amplifier and the Mach–Zehnder modulator. Digital predistortion counteracts the degrading effects and enables Baud rates up to  and modulation formats like 64-QAM and 128-QAM with the commercially available components. The transmitter digital signal processor performs digital predistortion on the input signals using the inverse transmitter model before sending the samples to the DAC.

Older digital predistortion methods only addressed linear effects. Recent publications also consider non-linear distortions. Berenguer et al models the Mach–Zehnder modulator as an independent Wiener system and the DAC and the driver amplifier are modeled by a truncated, time-invariant Volterra series. Khanna et al use a memory polynomial to model the transmitter components jointly. In both approaches the Volterra series or the memory polynomial coefficients are found using indirect-learning architecture. Duthel et al records, for each branch of the Mach-Zehnder modulator, several signals at different polarity and phases. The signals are used to calculate the optical field. Cross-correlating in-phase and quadrature fields identifies the timing skew. The frequency response and the non-linear effects are determined by the indirect-learning architecture.

Fiber cable types

An optical fiber cable consists of a core, cladding, and a buffer (a protective outer coating), in which the cladding guides the light along the core by using the method of total internal reflection. The core and the cladding (which has a lower-refractive-index) are usually made of high-quality silica glass, although they can both be made of plastic as well. Connecting two optical fibers is done by fusion splicing or mechanical splicing and requires special skills and interconnection technology due to the microscopic precision required to align the fiber cores.

Two main types of optical fiber used in optic communications include multi-mode optical fibers and single-mode optical fibers. A multi-mode optical fiber has a larger core (≥50 micrometers), allowing less precise, cheaper transmitters and receivers to connect to it as well as cheaper connectors. However, a multi-mode fiber introduces multimode distortion, which often limits the bandwidth and length of the link. Furthermore, because of its higher dopant content, multi-mode fibers are usually expensive and exhibit higher attenuation. The core of a single-mode fiber is smaller (<10 micrometers) and requires more expensive components and interconnection methods, but allows much longer and higher-performance links. Both single- and multi-mode fiber is offered in different grades.

In order to package fiber into a commercially viable product, it typically is protectively coated by using ultraviolet cured acrylate polymers and assembled into a cable. After that, it can be laid in the ground and then run through the walls of a building and deployed aerially in a manner similar to copper cables. These fibers require less maintenance than common twisted pair wires once they are deployed.

Specialized cables are used for long-distance subsea data transmission, e.g. transatlantic communications cable. New (2011–2013) cables operated by commercial enterprises (Emerald Atlantis, Hibernia Atlantic) typically have four strands of fiber and signals cross the Atlantic (NYC-London) in 60–70 ms. The cost of each such cable was about $300M in 2011.

Another common practice is to bundle many fiber optic strands within long-distance power transmission cable using, for instance, an optical ground wire. This exploits power transmission rights of way effectively, ensures a power company can own and control the fiber required to monitor its own devices and lines, is effectively immune to tampering, and simplifies the deployment of smart grid technology.

Amplification

The transmission distance of a fiber-optic communication system has traditionally been limited by fiber attenuation and by fiber distortion. By using optoelectronic repeaters, these problems have been eliminated. These repeaters convert the signal into an electrical signal and then use a transmitter to send the signal again at a higher intensity than was received, thus counteracting the loss incurred in the previous segment. Because of the high complexity with modern wavelength-division multiplexed signals, including the fact that they had to be installed about once every , the cost of these repeaters is very high.

An alternative approach is to use optical amplifiers which amplify the optical signal directly without having to convert the signal to the electrical domain. One common type of optical amplifier is an erbium-doped fiber amplifier (EDFA). These are made by doping a length of fiber with the rare-earth mineral erbium and laser pumping it with light with a shorter wavelength than the communications signal (typically 980 nm). EDFAs provide gain in the ITU C band at 1550 nm.

Optical amplifiers have several significant advantages over electrical repeaters. First, an optical amplifier can amplify a very wide band at once which can include hundreds of multiplexed channels, eliminating the need to demultiplex signals at each amplifier. Second, optical amplifiers operate independently of the data rate and modulation format, enabling multiple data rates and modulation formats to co-exist and enabling upgrading of the data rate of a system without having to replace all of the repeaters. Third, optical amplifiers are much simpler than a repeater with the same capabilities and are therefore significantly more reliable. Optical amplifiers have largely replaced repeaters in new installations, although electronic repeaters are still widely used when signal conditioning beyond amplification is required.

Wavelength-division multiplexing

Wavelength-division multiplexing (WDM) is the technique of transmitting multiple channels of information through a single optical fiber by sending multiple light beams of different wavelengths through the fiber, each modulated with a separate information channel. This allows the available capacity of optical fibers to be multiplied. This requires a wavelength division multiplexer in the transmitting equipment and a demultiplexer (essentially a spectrometer) in the receiving equipment. Arrayed waveguide gratings are commonly used for multiplexing and demultiplexing in WDM. Using WDM technology now commercially available, the bandwidth of a fiber can be divided into as many as 160 channels to support a combined bit rate in the range of .

Parameters

Bandwidth–distance product
Because the effect of dispersion increases with the length of the fiber, a fiber transmission system is often characterized by its bandwidth–distance product, usually expressed in units of MHz·km. This value is a product of bandwidth and distance because there is a trade-off between the bandwidth of the signal and the distance over which it can be carried. For example, a common multi-mode fiber with bandwidth–distance product of 500 MHz·km could carry a 500 MHz signal for 1 km or a 1000 MHz signal for 0.5 km.

Record speeds
Using wavelength-division multiplexing, each fiber can carry many independent channels, each using a different wavelength of light. The net data rate (data rate without overhead bytes) per fiber is the per-channel data rate reduced by the forward error correction (FEC) overhead, multiplied by the number of channels (usually up to eighty in commercial dense WDM systems ).

Standard fiber cables
The following summarizes research using standard telecoms-grade single-mode, single-solid-core fiber cables.

Specialized cables

The following summarizes research using specialized cables that allow spatial multiplexing to occur, use specialized tri-mode fiber cables or similar specialized fiber optic cables.

New techniques

Research from DTU, Fujikura and NTT is notable in that the team was able to reduce the power consumption of the optics to around 5% compared with more mainstream techniques, which could lead to a new generation of very power-efficient optic components.

Research conducted by the RMIT University, Melbourne, Australia, have developed a nanophotonic device that carries data on light waves that have been twisted into a spiral form and achieved a 100-fold increase in current attainable fiber optic speeds.
The technique is known as orbital angular momentum (OAM). The nanophotonic device uses ultra-thin sheets to measure a fraction of a millimeter of twisted light. Nano-electronic device is embedded within a connector smaller than the size of a USB connector and may be fitted at the end of an optical fiber cable.

Dispersion
For modern glass optical fiber, the maximum transmission distance is limited not by direct material absorption but by dispersion, the spreading of optical pulses as they travel along the fiber. Dispersion limits the bandwidth of the fiber because the spreading optical pulse limits the rate which pulses can follow one another on the fiber and still be distinguishable at the receiver. Dispersion in optical fibers is caused by a variety of factors.

Intermodal dispersion, caused by the different axial speeds of different transverse modes, limits the performance of multi-mode fiber. Because single-mode fiber supports only one transverse mode, intermodal dispersion is eliminated.

In single-mode fiber performance is primarily limited by chromatic dispersion, which occurs because the index of the glass varies slightly depending on the wavelength of the light, and, due to modulation, light from optical transmitters necessarily occupies a (narrow) range of wavelengths. Polarization mode dispersion, another source of limitation, occurs because although the single-mode fiber can sustain only one transverse mode, it can carry this mode with two different polarizations, and slight imperfections or distortions in a fiber can alter the propagation velocities for the two polarizations. This phenomenon is called birefringence and can be counteracted by polarization-maintaining optical fiber.

Some dispersion, notably chromatic dispersion, can be removed by a dispersion compensator. This works by using a specially prepared length of fiber that has the opposite dispersion to that induced by the transmission fiber, and this sharpens the pulse so that it can be correctly decoded by the electronics.

Attenuation
Fiber attenuation is caused by a combination of material absorption, Rayleigh scattering, Mie scattering, and losses in connectors. Material absorption for pure silica is only around 0.03 dB/km. Impurities in early optical fibers caused attenuation of about 1000 dB/km. Modern fiber has attenuation around 0.3 dB/km. Other forms of attenuation are caused by physical stresses to the fiber, microscopic fluctuations in density, and imperfect splicing techniques.

Transmission windows

Each effect that contributes to attenuation and dispersion depends on the optical wavelength. There are wavelength bands (or windows) where these effects are weakest, and these are the most favorable for transmission. These windows have been standardized, and the currently defined bands are the following:

Note that this table shows that current technology has managed to bridge the second and third windows that were originally disjoint.

Historically, there was a window used below the O band, called the first window, at 800–900 nm; however, losses are high in this region so this window is used primarily for short-distance communications. The current lower windows (O and E) around 1300 nm have much lower losses. This region has zero dispersion. The middle windows (S and C) around 1500 nm are the most widely used. This region has the lowest attenuation losses and achieves the longest range. It does have some dispersion, so dispersion compensator devices are used to remove this.

Regeneration
When a communications link must span a larger distance than existing fiber-optic technology is capable of, the signal must be regenerated at intermediate points in the link by optical communications repeaters. Repeaters add substantial cost to a communication system, and so system designers attempt to minimize their use.

Recent advances in fiber and optical communications technology have reduced signal degradation so far that regeneration of the optical signal is only needed over distances of hundreds of kilometers. This has greatly reduced the cost of optical networking, particularly over undersea spans where the cost and reliability of repeaters is one of the key factors determining the performance of the whole cable system. The main advances contributing to these performance improvements are dispersion management, which seeks to balance the effects of dispersion against non-linearity; and solitons, which use nonlinear effects in the fiber to enable dispersion-free propagation over long distances.

Last mile

Although fiber-optic systems excel in high-bandwidth applications, optical fiber has been slow to achieve its goal of fiber to the premises or to solve the last mile problem. However, FTTH deployment has increased significantly over the last decade and is projected to serve millions more subscribers in the near future. In Japan, for instance EPON has largely replaced DSL as a broadband Internet source. South Korea's KT also provides a service called FTTH (Fiber To The Home), which provides fiber-optic connections to the subscriber's home. The largest FTTH deployments are in Japan, South Korea, and China. Singapore started implementation of their all-fiber Next Generation Nationwide Broadband Network (Next Gen NBN), which is slated for completion in 2012 and is being installed by OpenNet. Since they began rolling out services in September 2010, network coverage in Singapore has reached 85% nationwide.

In the US, Verizon Communications provides a FTTH service called FiOS to select high-ARPU (Average Revenue Per User) markets within its existing territory. The other major surviving ILEC (or Incumbent Local Exchange Carrier), AT&T, uses a FTTN (Fiber To The Node) service called U-verse with twisted-pair to the home. Their MSO competitors employ FTTN with coax using HFC. All of the major access networks use fiber for the bulk of the distance from the service provider's network to the customer.

The globally dominant access network technology is EPON (Ethernet Passive Optical Network). In Europe, and among telcos in the United States, BPON (ATM-based Broadband PON) and GPON (Gigabit PON) had roots in the FSAN (Full Service Access Network) and ITU-T standards organizations under their control.

Comparison with electrical transmission

The choice between optical fiber and electrical (or copper) transmission for a particular system is made based on a number of trade-offs. Optical fiber is generally chosen for systems requiring higher bandwidth or spanning longer distances than electrical cabling can accommodate.

The main benefits of fiber are its exceptionally low loss (allowing long distances between amplifiers/repeaters), its absence of ground currents and other parasite signal and power issues common to long parallel electric conductor runs (due to its reliance on light rather than electricity for transmission, and the dielectric nature of fiber optic), and its inherently high data-carrying capacity. Thousands of electrical links would be required to replace a single high-bandwidth fiber cable. Another benefit of fibers is that even when run alongside each other for long distances, fiber cables experience effectively no crosstalk, in contrast to some types of electrical transmission lines. Fiber can be installed in areas with high electromagnetic interference (EMI), such as alongside utility lines, power lines, and railroad tracks. Nonmetallic all-dielectric cables are also ideal for areas of high lightning-strike incidence.

For comparison, while single-line, voice-grade copper systems longer than a couple of kilometers require in-line signal repeaters for satisfactory performance, it is not unusual for optical systems to go over , with no active or passive processing. Single-mode fiber cables are commonly available in  lengths, minimizing the number of splices required over a long cable run. Multi-mode fiber is available in lengths up to 4 km, although industrial standards only mandate 2 km unbroken runs.

In short-distance and relatively low-bandwidth applications, electrical transmission is often preferred because of its
 Lower material cost, where large quantities are not required
 Lower cost of transmitters and receivers
 Capability to carry electrical power as well as signals (in appropriately designed cables)
 Ease of operating transducers in linear mode.

Optical fibers are more difficult and expensive to splice than electrical conductors. And at higher powers, optical fibers are susceptible to fiber fuse, resulting in catastrophic destruction of the fiber core and damage to transmission components.

Because of these benefits of electrical transmission, optical communication is not common in short box-to-box, backplane, or chip-to-chip applications; however, optical systems on those scales have been demonstrated in the laboratory.

In certain situations, fiber may be used even for short-distance or low-bandwidth applications, due to other important features:
 Immunity to electromagnetic interference, including nuclear electromagnetic pulses.
 High electrical resistance, making it safe to use near high-voltage equipment or between areas with different earth potentials.
 Lighter weight—important, for example, in aircraft.
 No sparks—important in flammable or explosive gas environments.
 Not electromagnetically radiating, and difficult to tap without disrupting the signal—important in high-security environments.
 Much smaller cable size—important where the pathway is limited, such as networking an existing building, where smaller channels can be drilled and space can be saved in existing cable ducts and trays.
 Resistance to corrosion due to non-metallic transmission medium

Optical fiber cables can be installed in buildings with the same equipment that is used to install copper and coaxial cables, with some modifications due to the small size and limited pull tension and bend radius of optical cables. Optical cables can typically be installed in duct systems in spans of 6000 meters or more depending on the duct's condition, layout of the duct system, and installation technique. Longer cables can be coiled at an intermediate point and pulled farther into the duct system as necessary.

Governing standards
In order for various manufacturers to be able to develop components that function compatibly in fiber optic communication systems, a number of standards have been developed. The International Telecommunication Union publishes several standards related to the characteristics and performance of fibers themselves, including
 ITU-T G.651, "Characteristics of a 50/125 μm multimode graded index optical fibre cable"
 ITU-T G.652, "Characteristics of a single-mode optical fibre cable"

Other standards specify performance criteria for fiber, transmitters, and receivers to be used together in conforming systems. Some of these standards are:
 100 Gigabit Ethernet
 10 Gigabit Ethernet
 Fibre Channel
 Gigabit Ethernet
 HIPPI
 Synchronous Digital Hierarchy
 Synchronous Optical Networking
 Optical transport network (OTN)

TOSLINK is the most common format for digital audio cable using plastic optical fiber to connect digital sources to digital receivers.

See also
 Dark fiber
 Fiber to the x
 Free-space optical communication

Notes

References

 Encyclopedia of Laser Physics and Technology
 Fiber-Optic Technologies by Vivek Alwayn

Further reading
 Keiser, Gerd. (2011). Optical fiber communications, 4th ed. New York, NY: McGraw-Hill,
 Senior, John. (2008). Optical Fiber Communications: Principles and Practice, 3rd ed. Prentice Hall.

External links

 "Understanding Optical Communications" An IBM redbook
 Fiber Optics - Internet, Cable and Telephone Communication

Photonics

Fiber-optic communication


Livraria Cultura is a chain of bookstores in Brazil, founded in 1948 in São Paulo by Eva Herz.

History
In 1947, Eva Herz, daughter of German immigrants, set up a book rental service called Biblioteca Circulante (Circulating Library) at her home in Alameda Lorena, São Paulo. The books were imported from Europe and their clientele was mainly immigrants. The service became popular and the circulating library started to borrow books from Brazilian authors, as well as to sell them.

In 1969, Herz moved the bookstore, now called Livraria Cultura,  to the Conjunto Nacional on Avenida Paulista. Eva's son, Pedro Herz, became her partner in the company.

The company expanded to a chain present in several cities in Brazil, such as Brasília, Campinas, Curitiba, Fortaleza, Porto Alegre, Recife, Ribeirão Preto, and Salvador, as well as having a store specialized in comics, videogames and other pop culture goods, called Geek.Etc.Br  in São Paulo. On July 19, 2017, Livraria Cultura acquired the operation of Fnac in Brazil without disclosing figures. At the end of the same year the bookstore purchased the online marketplace Estante Virtual.

After years of financial losses, which included the closing of the physical units in Rio de Janeiro, the company filed a request for judicial recovery on October 24, 2018, seeking to renegotiate its debts with book publishers and other creditors of the company.

In February, 9th 2023, the Livraria Cultura had its bankruptcy decreed by the 2nd Bankruptcy and Judicial Recovery Court of São Paulo.
Days later, the bankruptcy was reversed, without any physical or virtual store being closed, due to an injunction granted by Judge J. B. Franco de Godói.
On May 15, the board judged the Interlocutory Appeal, overturning the injunction and declaring bankruptcy again.
On June 26, the store located in Conjunto Nacional was closed, while the Porto Alegre store and the virtual store continued to operate normally for an indefinite period of time, despite the bankruptcy.
Days later, however, Minister Raul Araújo, of the Superior Court of Justice, granted an injunction suspending the bankruptcy again. The store located in Conjunto Nacional reopened at 2pm on July 6th.

References

External links
 Livraria Cultura website

Bookshops of Brazil
Culture in São Paulo
Companies based in São Paulo

Livraria Cultura


Suburbanisation or Suburbanization is when people move from the city center to the outskirts of the city, or the suburbs. Suburbanization is linked with urbanization, where people move from the countryside (called rural areas) to the cities. There is also a process called counterurbanization,  where a city loses its attractiveness, and people move back to the countryside. If suburbanisation happens in very large cities, this can lead to the establishment of new Satellite cities and  commuter towns. Functionally satelite cities and commuter towns are linked to the main city (as most people still work in the main city, and commute to work there).

Effects of suburbanisation on the city
There are a number of problems linked to suburbanization:

 The main city still pays for much of the infrastructure, also for the suburbs, but it doesn't get paid that much (as most people live in the suburbs)
 In the main city, different ethnic and economic groups lived together. When they move out the suburbs, they will often segregate (living in some suburbs may be more expensive, so that poorer people won't move there). Also, ethnic communities that were mixed in the city, may get segregated in the suburbs.
 The number and nature of jobs in the main city may change.
 Often, the structure of commerce changes. An example for this is the construction of large shopping centers on the outskirts vs. smaller shops in the city centers.
 Generally, the infrastructure in the main city may be oversized.

Effects in the suburbs
In the suburbs, suburbanization also has effects:

 Land values rise, as there's not enough land for housing and commerce
 Generally, more land is needed, because shopping and housing are of lower density than in the main city
 Commuting to the main city poses a higher load on infrastructure (epsecially roads)
 There's a higher need for schools
 There may be conflicts between the people that were there before, and those that moved there recently.
 Rising tax levels
 A loss of culural identity.

History
The first  moves to suburbanization were the establishment of garden cities in England, and the establishment of better off neighbourhoods in the US and Europe. Both happened in the late 19th and early 20th century. Suburbanization and urban sprawl started in the U.S. in the 1920s, when cars became affordable. In 1939, 13 percent of the peolple in the U.S. lived in suburbs; in 2010, they were over 50 percent.

In the 1960s, living in the cities became much more expensive in Europe, so many commuter towns were built.

In Eastern Europe, suburbanization started after 1990; before there were few  ways to build a private home. In Asia, suburbanization started when the colonial powers (mostly England and the Netherlands) started to build suburbs for the mansions of their people.

Informal settlements, such as  slums or Favelas, are also a form of suburbanization in developing countries. In China, there has  a strong movement to move outside the cities since 1995. It is not a form of suburbanization, as it is driven by large industrial complexes. The owners of these complexes also build settlements to house the people who work there.

References

Urban planning
Urban geography

Suburbanisation


Hermann Eris Busse (9 March 1891, Freiburg im Breisgau – 15 August 1947) was a German novelist and literary critic. He is best known for his Black Forest novels and his biography of the 17th-century German writer Hans Jakob Christoph von Grimmelshausen.

Major works
 Bauernadel (trilogy of novels), 1930.
 Der Letzte Bauer (novel), 1930.
Mein Leben (autobiography), 1935.
Grimmelshausen, 1939.
Glorian und die Frevlerin (stories), 1944.

1891 births
1947 deaths
Writers from Freiburg im Breisgau
People from the Grand Duchy of Baden
German literary critics
Writers from Baden-Württemberg
German male novelists
20th-century German novelists
20th-century German male writers
German male non-fiction writers

Hermann Eris Busse


The Year of the Hare () is a 1975 picaresque novel by Finnish author Arto Paasilinna. It tells the story of Kaarlo Vatanen, a frustrated journalist, who, after nearly killing a hare with his car, turns away from an unhappy and unwholesome life. On an impulse, Vatanen abruptly abandons his urban lifestyle, job, and wife, in exchange for the freedom of the road and the wilderness, living off his cash savings and casual employment, all the time accompanied by the hare which he has nursed back to health and kept as a pet. A year of unlikely encounters and adventures ensues, during the course of which Vatanen repeatedly runs afoul of the law and conventional mores but manages to stay afloat thanks to the help and understanding of other sympathetic free spirits.

The novel has been translated into 29 languages including English, Bulgarian, Chinese, Croatian, Czech, Dutch, Estonian, French, German, Hebrew, Hungarian, Italian, Japanese, Korean, Rumanian, Russian, Swedish, Slovenian, Turkish, and Ukrainian. It is Paasilinna's most widely read work and was included in 1994 in the UNESCO Collection of Representative Works which funded the 1995 English translation by Herbert Lomas. It was adapted twice into feature films: a 1977 Finnish film called The Year of the Hare, and a 2006 French film directed by Marc Rivière called Le Lièvre de Vatanen.

Notes

References
 Arto Paasilinna, Herbert Lomas (tr.). The Year of the Hare.  (1995, 1st ed.).  (2006, 6th ed.)

External links
Reviews
 The Year of the Hare at The New York Times
 The Year of the Hare at World Literature Today (via Article Archives, JavaScript required)
 The Year of the Hare at complete review
 The Year of the Hare at The Literary Traveller

1975 novels
20th-century Finnish novels
Finnish comedy novels
Satirical novels
Picaresque novels
Finnish novels adapted into films
Novels about rabbits and hares
Novels set in Finland
Novels by Arto Paasilinna

The Year of the Hare (novel)


Hamid David Nahai (born 1959) is an Iranian-American environmental attorney, political activist, and former head of the Los Angeles Department of Water and Power.

Early life and education
David Nahai was born into a Jewish family in 1959 in the Iranian capital, Tehran. In 1969 Nahai moved to the United Kingdom where he later attended the London School of Economics. After the 1979 Islamic Revolution, Nahai relocated to the United States where he received his JD from the University of California, Berkeley.

Career and Los Angeles DWP
Nahai founded the Los Angeles based Nahai Law Corporation in 1992. The firm specializes in "real estate, corporate, environmental and commercial law." Nahai served several terms on the Regional Water Quality Control Board before being appointed to the DWP board of commissioners in 2005 by Los Angeles mayor Antonio Villaraigosa.

In December 2007, Villaraigosa elevated Nahai to "the post of DWP general manager and chief executive officer". Nahai's approximately two-year tenure was marked by a heightened emphasis on renewable energy sources and conservation. During his time at the DWP, the department increased its renewable energy portfolio to 14 percent and the city of Los Angeles saw its lowest monthly water use in 32 years (in June 2009).

In October 2009, Nahai resigned as general manager of the Los Angeles Department of Water and Power, citing his desire to devote his time and resources to the Clinton Climate Initiative that he had joined shortly before. The Clinton Climate Initiative is an organization founded by former US president Bill Clinton with the aim of fighting the causes of global climate change.

Family
David Nahai is married to novelist and USC professor Gina Nahai. They have three children and currently reside in Los Angeles.

References

1959 births
Living people
American people of Iranian descent
Iranian Jews

David Nahai


Camisa de Vênus (the old-fashioned Portuguese term for "condom") was a Brazilian rock group from Bahia whose peak of popularity was in the mid 1980s. Former lead singer, Marcelo Nova would be the producer and partner of Raul Seixas in his last years. The band has made several comebacks for short tours but is now on tour in promotion of its new record "Dançando na Lua"

Early years
Camisa de Vênus was formed in 1982, in Salvador, Bahia with Marcelo Nova (vocals), Robério Santana (bass guitar),
Karl Hummel (guitar) and Gucstavo Müllen (drums). After the band made it to the mainstream, Gustavo picked the lead guitar and a new drummer, Aldo Machado, was hired. The band debuted in 1982 with a single ("Controle Total"/"Meu Primo Zé") featuring most of the band's hallmarks.

The first, namesake was a punk rock album, but drew media attention, especially for its shock value, with the song "Bete Morreu" (Beth Died) becoming an underground hit, and the group was invited to play on TV. In July 2016, this album was elected by Rolling Stone Brasil as the 7th best Brazilian punk rock album. They soon released a second album, Batalhões de Estranhos (Platoons of Strangers), which brought them their first mainstream hit: "Eu Não Matei Joana D'Arc" (I Didn't Kill Joan of Arc).

Style
Musically, Camisa de Vênus draws more heavily from early rockers (like Chuck Berry)  than their contemporaries, especially for the guitar style. They also bring the rhythm section forward, like in their major hit, "Simca Chambord", featuring an interesting bass/guitar interplay with massive, nonstopping and thumping drums. Marcelo Nova's vocals are deep, rascant, full of improvisation and notoriously freestyle, showing more interest on interpreting the lyrics' content than on following thoroughly the melody. Camisa de Vênus has got a punk rock influence too.

The lyrics are very mature, since the beginning, showing political attitude and critique of customs. They can also be quite offensive and explicit. When performing live the group used to point them with bad words for their shock value in a time when censorship still existed. Their lyrics touched sensitive points and made a great deal of noise in the eighties, especially "Eu Não Matei Joana D'Arc" (I Didn't Kill Joan of Arc), for its implicit allusions to free love and lesbianism, "Sílvia", the first time ever the word "puta" (whore) was heard on a record, "Passamos por Isso" (We've Been Through That), which protests against the recording industry, and "Pronto Pro Suicídio" (Ready For Suicide), a nihilist protest.

The heyday
After three years touring and composing, the group had reached a level of maturity that most other Brazilian rock groups had only dreamt of. In 1986 they issued Viva! (Live!) -- maybe the first true "live" album by a Brazilian artist, without any post-production, edition or overdubs. This record showed to the country the band's true face: punkish, dirty and noisy. It is also famous for the use of several explicit words that had been censored in the original studio versions. "Eu Não Matei Joana D'Arc", for instance had the line "Nós só nos encontramos para passear no parque" (we only met to walk through the park) replaced by "Nós só nos encontramos para trepar no parque" (we only met to fuck in the park).

That same year they issued Correndo o Risco (Taking the Risk), their most successful album ever, with the hits "Só O Fim" (Just The End), "Simca Chambord", "Deus me Dê Grana" (God Give Me Money) and "A Ferro e Fogo" (By Iron and Fire) -- their only recording with a live orchestra (!), something quite unusual given their style.

However the band would not last long. In 1987, after a mild reception of their fifth album, Duplo Sentido (Double Meaning), the band split.

Marcelo Nova and Raul Seixas
Marcelo Nova chose to work with Raul Seixas—who had previously jammed with Camisa de Vênus and composed with them their hit "Muita Estrela, Pouca Constelação" (Too Many Stars, Too Few Constellations) from the album "Duplo Sentido".

They produced a quite underrated album called A Panela do Diabo (Devil's Saucepan) which is mostly famous for being Seixas' last recording in life. Raul was actually quite ill then and their live performances were pitiful, with Raul babbling the words and unable to play his guitar. He would die short after, supposedly of cirrhosis, but he also had diabetes and had been addicted to several drugs and to alcohol for years.

The comeback
In 1995 Marcelo Nova and some of the original members reformed the band for a successful country-wide tour, captured in Plugado! (Plugged!), that same year.

Their comeback benefitted from their label promoting them steadily through the years, issuing two compilations, Liberou Geral (All Free), in 1988, and Bota Pra Fudê (Let's F**k It All Up), in 1990.

In 1996 they released Quem É Você? (Who Are You?), with Marcelo Nova, Karl Hummel, Robério Santana, Luiz Carlini, Frank Paolillo and Carlos Calazans, notably co-produced by Eric Burdon, who also made a guest appearance in the album singing along with Nova in the band's version of "Don't Let Me Be Misunderstood". Despite good reviews, this was their last effort together (so far).

Legacy
Camisa de Vênus played an important role during the last days of the Brazilian dictatorship by ridiculing censorship and introducing clever criticism of the customs of pop music. Marcelo Nova was also responsible for keeping Raul Seixas visible in the media in his last days, which helped revalue his work after his death.

Famous Hits
 "Eu Não Matei Joana D'Arc"—A kind of a "spy story": a young man is charged with the murder of a young woman whose burnt corpse has been found in a park. He blames the CIA, the KGB and the Catholic Church.
 "Simca Chambord"—A young man recalls his childhood, before the 1964 coup d'état, (when his father had a Simca Chambord car) and blames the armed forces for crushing his childhood dreams.
 "Passamos Por Isso"—A singer tells the story of his band, and all trials and tribulations they had to overcome to be "allowed" to play rock and roll instead of MPB.
 "Lena"—A man scolds his ex-girlfriend, now a prostitute who "works" with famous men.
 "Só O Fim"—A prophet preaches in the streets that social tension and stress are symptoms that the end of the world is near.
 "Homem Não Chora"—A dark tale of the common man - Badly parented, misguided by catholic school, working the hours, waiting for the pension... But still got to remember what he was taught - "Homem não chora" (Men don't cry).

Records

 "Controle Total" (Total Control) (EP) — 1983
 "Camisa de Vênus" (Camisa de Vênus) — 1983
 "Batalhões de Estranhos" (Battalions of Strangers) — 1984
 "Viva" (Live!) — 1986
 "Correndo o Risco" (Taking the Risks) — 1986
 "Duplo Sentido" (Double Meaning) — 1987
 "Liberou Geral" (Released General)(Compilation) -- 1988
 "Bota Pra Fudê" (Fuck it Up) (Compilation) -- 1990
 "Plugado!" (Plugged In) — 1995
 "Quem é Você?" (Who Are You?) — 1996
 "Dançando na Lua" (Dancing on the Moon) — 2016
 "Agulha No Palheiro" (Needle in the Haystack) — 2021

References

Brazilian rock music groups
Musical groups established in 1982
Musical groups disestablished in 1987
1982 establishments in Brazil
1987 disestablishments in Brazil
Musical groups reestablished in 1994
Musical groups disestablished in 1997
1994 establishments in Brazil
1997 disestablishments in Brazil
Musical groups reestablished in 2009
2009 establishments in Brazil

Camisa de Vênus


Gideon Algernon Mantell MRCS FRS (3 February 1790 – 10 November 1852) was an English obstetrician, geologist and palaeontologist. His attempts to reconstruct the structure and life of Iguanodon began the scientific study of dinosaurs: in 1822 he was responsible for the discovery (and the eventual identification) of the first fossil teeth, and later much of the skeleton, of Iguanodon. Mantell's work on the Cretaceous of southern England was also important.

Early life and medical career

Mantell was born in Lewes, Sussex as the fifth-born child of Thomas Mantell, a shoemaker, and Sarah Austen. He was raised in a small cottage in St. Mary's Lane with his two sisters and four brothers. As a youth, he showed a particular interest in the field of geology. He explored pits and quarries in the surrounding areas, discovering ammonites, shells of sea urchins, fish bones, coral, and worn-out remains of dead animals. The Mantell children could not study at local grammar schools because the elder Mantell was a follower of the Methodist church and the 12 free schools were reserved for children who had been brought up in the Anglican faith. As a result, Gideon was educated at a dame school in St. Mary's Lane, and learned basic reading and writing from an old woman. After the death of his teacher, Mantell was schooled by John Button, a philosophically radical Whig who shared similar political beliefs with Mantell's father. Mantell spent two years with Button, before being sent to his uncle, a Baptist minister, in Swindon, for a period of private study.

Mantell returned to Lewes at age 15. With the help of a local Whig party leader, Mantell secured an apprenticeship with a local surgeon named James Moore. He served as an apprentice to Moore in Lewes for a period of five years, in which he took care of Mantell's dining, lodging and medical issues. Mantell's early apprenticeship duties included cleaning vials, as well as separating and arranging drugs. Soon, he learned how to make pills and other pharmaceutical products. He delivered Moore's medicines, kept his accounts, wrote out bills and extracted teeth from his patients. On 11 July 1807, Thomas Mantell died at the age of 57. He left his son some money for his future studies. As his time in apprenticeship began to wind down, he began to anticipate his medical education. He began to teach himself human anatomy, and he ultimately detailed his new-found knowledge in a volume entitled The Anatomy of the Bones, and the Circulation of Blood, which contained dozens of detailed drawings of fetal and adult skeletal features. Soon, Mantell began his formal medical education in London. He received his diploma as a Member of the Royal College of Surgeons in 1811. Four days later, he received a certificate from the Lying-in Charity for Married Women at Their Own Habitations that allowed him to act in midwifery duties.

He returned to Lewes, and immediately formed a partnership with his former master, James Moore. In the wake of the cholera, typhoid and smallpox epidemics, Mantell found himself quite busy attending to more than 50 patients a day and delivering between 200 and 300 babies a year. As he later recalled, he would have to stay up for "six or seven nights in succession" due to his overwhelming doctoral duties. He was also able to increase his practice's profits from £250 to £750 a year. Although mainly occupied with running his busy country medical practice, he spent his little free time pursuing his passion, geology, often working into the early hours of the morning, identifying fossil specimens he found at the marl pits in Hamsey. In 1813, Mantell began to correspond with James Sowerby. Sowerby, a naturalist and illustrator who catalogued fossil shells, received from Mantell many fossilised specimens. In appreciation for the specimens Mantell had provided, Sowerby named one of the species Ammonites mantelli. On 7 December, Mantell was elected as a fellow of the Linnean Society of London. Two years later, he published his first paper, on the characteristics of the fossils found in the Lewes area.

In 1816, he married Mary Ann Woodhouse, the 20-year-old daughter of one of his former patients who had died three years earlier. Since she was not 21 and still technically a minor under English law, she had to obtain permission from her mother and a special licence to marry Mantell. After obtaining consent and the licence, she married Mantell on 4 May at St. Marylebone Church. That year, he purchased his own medical practice and took up an appointment at the Royal Artillery Hospital, at Ringmer, Lewes.

Geological research

Inspired by Mary Anning's sensational discovery of a fossilised animal resembling a huge crocodile (later identified as an ichthyosaur) at Lyme Regis in Dorset, Mantell became passionately interested in the study of the fossilised animals and plants found in his area. The fossils he had collected from the region, near The Weald in Sussex, were from the chalk downlands covering the county. The chalk is part of the Upper Cretaceous System and the fossils it contains are marine in origin. But by 1819, Mantell had begun acquiring fossils from a quarry, at Whitemans Green, near Cuckfield. These included the remains of terrestrial and freshwater ecosystems, at a time when all the known fossil remains from Cretaceous England, hitherto, were marine in origin. He named the new strata the Strata of Tilgate Forest, after an historical wooded area and it was later shown to belong to the Lower Cretaceous.

By 1820, he had started to find very large bones at Cuckfield, even larger than those discovered by William Buckland, at Stonesfield in Oxfordshire. Then, in 1822, shortly before finishing his first book (The Fossils of South Downs), his wife found several large teeth (although some historians contend that they were in fact discovered by himself), the origin of which he could not ascertain. In 1821 Mantell planned his next book on the geology of Sussex. It was an immediate success with two hundred subscribers including King George IV at Carlton House Palace, who wrote a letter stating, "His majesty is pleased to command that his name should be placed at the head of the subscription list for four copies."

How the king heard of Mantell is unknown, but Mantell's response is known. Galvanised and encouraged, Mantell showed the teeth to other scientists but they were dismissed as belonging to a fish or mammal and from a more recent rock layer than the other Tilgate Forest fossils. The eminent French anatomist, Georges Cuvier, identified the teeth as those of a rhinoceros.

Although according to Charles Lyell, Cuvier made this statement after a late party and apparently had some doubts when reconsidering the matter when he awoke, fresh in the morning. "The next morning he told me that he was confident that it was something quite different." Strangely, this change of opinion did not make it back to Britain where Mantell was mocked for his error. Mantell was still convinced that the teeth had come from the Mesozoic strata and finally recognised that they resembled those of the iguana, but were twenty times larger. He surmised that the owner of the remains must have been at least 60 feet (18 metres) in length.

Recognition

He tried in vain to convince his peers that the fossils were from Mesozoic strata, by carefully studying rock layers. William Buckland famously disputed Mantell's assertion, by claiming that the teeth were of fish.

When it was proved Mantell was correct in 1825, the only question was what to call his new reptile. His original name was "Iguana-saurus" but he then received a letter from William Daniel Conybeare: "Your discovery of the analogy between the Iguana and the fossil teeth is very interesting but the name you propose will hardly do, because it is equally applicable to the recent iguana. Iguanoides or Iguanodon would be better." Mantell took this advice to heart and called his creature Iguanodon.

Years later, Mantell had acquired enough fossil evidence to show that the dinosaur's forelimbs were much shorter than its hind legs, therefore proving they were not built like a mammal as claimed by Sir Richard Owen. Mantell went on to demonstrate that fossil vertebrae, which Owen had attributed to a variety of different species, all belonged to Iguanodon. He also named a new genus of dinosaur called Hylaeosaurus and as a result became an authority on prehistoric reptiles.

Later years
In 1833, Mantell relocated to Brighton but his medical practice suffered.  He was almost rendered destitute, but for the town's council, which promptly transformed his house into a museum. There he gave a series of lectures that were published in 1838 with the title The wonders of geology, or, A familiar exposition of geological phenomena: being the substance of a course of lectures delivered at Brighton. The museum in Brighton ultimately failed as a result of Mantell's habit of waiving the entrance fee. Financially destitute, Mantell offered to sell the entire collection to the British Museum in 1838 for £5,000, accepting the counter-offer of £4,000. He moved to Clapham Common in South London, where he continued his work as a doctor.

Mary Mantell left her husband in 1839. That same year, Gideon's son Walter emigrated to New Zealand. Walter later sent his father some important fossils from New Zealand. Gideon's daughter, Hannah, died in 1840.

In 1841 he began to suffer from what would eventually be diagnosed as scoliosis, possibly precipitated by a carriage accident. Despite being bent, crippled and in constant pain, he continued to work with fossilised reptiles and published a number of scientific books and papers until his death in November the 10th  1852.  He moved to [Pimlico] in 1844 and began to take [opium], as a painkiller, in 1845.

Death and legacy

On 10 November 1852, Mantell took an overdose of opium and later lapsed into a coma. He died that afternoon. His post-mortem by William Adams showed that he had been suffering from severe lumbar scoliosis, leading to the Adams Forward Bend Test as a diagnostic tool. A section of Mantell's spine was removed, preserved and stored on a shelf at the Royal College of Surgeons of England. It remained there until 1969 when it was destroyed due to lack of space.

Mantell's surgery, on the south side of Clapham Common, is now a dental surgery.

At the time of his death Mantell was credited with discovering four of the five genera of dinosaurs then known.

In 2000, in commemoration of Mantell's discovery and his contribution to the science of palaeontology, the Mantell Monument was unveiled at Whiteman's Green, Cuckfield. The monument has been confirmed as the location of the Iguanodon fossils that Mantell first described in 1822.

He is buried at West Norwood Cemetery within a sarcophagus attributed to Amon Henry Wilds that replicates the sanctuary of Natakamani's Temple of Amun. (The name ammonite is, coincidentally, derived from Amun.)

Works by Mantell
Sixty-seven books and memoirs appear in Agassiz and Strickland's Bibliographia Zoologiæ, and forty-eight scientific papers in the Royal Society's Catalogue.
The Fossils of the South Downs. Royal 4to, 42 plates. London 1822. This was his first book, the plates of which were drawn by his wife. Expensive, at £3. 3/- (three guineas). At double the price, plates were hand-coloured.
Outlines of the natural history of the environs of Lewes. 4to, 24pp, 3pl. Lewes, 1824.
Illustrations of the Geology of Sussex, containing figures and descriptions of the fossils of Tilgate Forest. Royal 4to, 20 plates, £2. 15s. 6d. 1827.
The Geological Age of Reptiles. In Jameson's Edinburgh Philosophical Journal, 1831, Vol. 11, pp. 81–85
A Narrative of the Visit of their most Gracious Majesties William IV and Queen Adelaide, to the Ancient Borough of Lewes, on the 22nd of October 1830. London: Lupton Relfe, 1831.
The Geology of the South-East of England. 8vo, with coloured maps, sections, and numerous plates, £1. 1/-. 1833.
Thoughts on a Pebble. 1836. 8th edition, 1849
The Wonders of Geology or, a familiar exposition of geological phenomena: being the substance of a course of lectures delivered at Brighton. 2 vols, London, 1838. Lithographic plates drawn by his wife. Data from 4th ed of 1840: vol 1: 428p, frontis & 4 plates; vol 2: pages 429795 plus appendix, glossary and other material, coloured frontis & 10 coloured plates, most drawn by his wife. Mantell's most extensive work.
The Medals of Creation. 2 vols, 1844.
A Day's Ramble in and about the Antient Town of Lewes. London: Henry G. Bohn, 1846.
Thoughts on Animalcules. small 4to, 144p, 12 coloured plates. London: Murray, 1846. 1850 title: The invisible world revealed by the microscope or, thoughts on animalcules.
Geological Excursions round the Isle of Wight and along the adjacent Coast of Dorsetshire. 1847.

Petrifactions and their teachings. 1851.

References

Sources

US edition: Terrible Lizard: the first dinosaur hunters and the birth of a new science. New York: Henry Holt and Company, 2000.

External links

A History of Dinosaur Hunting and Reconstruction
Schedule of Mantell related tours and events in and around Lewes and Brighton
Gideon Mantell Biography at Strange Science.net
Mantell and Wilds by the Friends of West Norwood Cemetery
The Medals of Creation (1844) First Lessons in Geology and in the Study of Organic Remains by Gideon Mantell
The journal of Gideon Mantell, Hathi Trust
Scanned copy of The Fossils of the South Downs (1822)

1790 births
1852 deaths
English geologists
English palaeontologists
19th-century English medical doctors
English obstetricians
Fellows of the Royal Society
People from Lewes
Burials at West Norwood Cemetery
Wollaston Medal winners
Royal Medal winners
Drug-related suicides in England

Gideon Mantell


The can-can (also spelled cancan as in the original French /kɑ̃kɑ̃/) is a high-energy, physically demanding dance that became a popular music-hall dance in the 1840s, continuing in popularity in French cabaret to this day. Originally danced by couples, it is now traditionally associated with a chorus line of female dancers. The main features of the dance are the vigorous manipulation of skirts and petticoats, along with high kicks, splits, and cartwheels.

History

The can-can is believed to have evolved from the final figure in the quadrille, a social dance for four or more couples. The exact origin of the dance is obscure, but the steps may have been inspired by a popular entertainer of the 1820s, Charles-François Mazurier (1798–1828), well known for his mime and acrobatic dance, including the grand écart or jump splits—both popular features of the can-can; his greatest success was in Jocko, or The Brazilian Ape (1825).

The dance was considered scandalous, and for a while there were attempts to suppress it. This may have been partly because in the 19th century, women wore pantalettes, which had an open crotch, and the high kicks were intentionally revealing. There is no evidence that can-can dancers wore special closed underwear, although it has been said that the Moulin Rouge management did not permit dancers to perform in "revealing undergarments". Occasionally, people dancing the can-can were arrested, but there is no record of its being banned, as some accounts claim. Throughout the 1830s, it was often groups of men, particularly students, who danced the can-can at public dance-halls.

As the dance became more popular, professional performers emerged, although it was still danced by individuals, not by a chorus line. A few men became can-can stars in the 1840s to 1861 and an all-male group known as the  performed in London in 1870. However, women performers were much more widely known.

By the 1890s, it was possible to earn a living as a full-time dancer and stars such as La Goulue and Jane Avril emerged, who were highly paid for their appearances at the Moulin Rouge and elsewhere. The most prominent male can-can dancer of the time was Valentin le Désossé (Valentin the Boneless), a frequent partner of La Goulue. The professional dancers of the Second Empire and the fin de siècle developed the can-can moves that were later incorporated by the choreographer Pierre Sandrini in the spectacular "French Cancan", which he devised at the Moulin Rouge in the 1920s and presented at his own Bal Tabarin from 1928. This was a combination of the individual style of the Parisian dance-halls and the chorus-line style of British and American music halls.

Outside France
Outside France, the can-can achieved popularity in music halls, where it was danced by groups of women in choreographed routines. This style was imported back into France in the 1920s for the benefit of tourists, and the "French Cancan" was born—a highly choreographed routine lasting ten minutes or more, with the opportunity for individuals to display their "specialities". The main moves are the high kick or battement, the  (quick rotary movement of lower leg with knee raised and skirt held up), the  (turning on one leg, while grasping the other leg by the ankle and holding it almost vertically), the cartwheel and the grand écart (the flying or jump splits). It has become common practice for dancers to scream and yelp while performing the can-can.

The can-can was introduced in America on 23 December 1867 by Giuseppina Morlacchi, dancing as a part of The Devil's Auction at the Theatre Comique in Boston. It was billed as "Grand Gallop Can-Can, composed and danced by Mlles. Morlacchi, Blasina, Diani, Ricci, Baretta ... accompanied with cymbals and triangles by the coryphees and corps de ballet." The new dance received an enthusiastic reception.

By the 1890s the can-can was out of style in New York dance halls, having been replaced by the hoochie coochie.

The can-can became popular in Alaska and Yukon, Canada, where theatrical performances feature can-can dancers to the present day.

In other arts

Many composers have written music for the can-can. The most famous is French composer Jacques Offenbach's  in his operetta  (Orpheus in the Underworld) (1858). However, the galop is actually another sort of dance. Other examples occur in Franz Lehár's operetta The Merry Widow (1905) and Cole Porter's musical play Can-Can (1954), which formed the basis for the 1960 musical film Can-Can starring Frank Sinatra and Shirley MacLaine. Some other songs that have become associated with the can-can include Aram Khachaturian's "Sabre Dance" from his ballet Gayane (1938) and the music hall standard "Ta-ra-ra Boom-de-ay". In 1955 Jean Renoir's film French Cancan, starring Jean Gabin as the director of a music hall which features the can-can, was released.

The can-can has often appeared in ballet, such as Léonide Massine's  (1919) and  (1938), as well as The Merry Widow. Another example is the climax of Jean Renoir's film French Cancan. A well-known can-can occurs at the finale of the "Dance of the Hours" from the opera  by Amilcare Ponchielli.

French painter Henri de Toulouse-Lautrec produced several paintings and a large number of posters of can-can dancers. Other painters of the can-can included Georges Seurat, Georges Rouault, and Pablo Picasso.

The can-can has appeared in numerous film and TV productions. The 2009 anime series Fairy Tail featured the music as one of its themes, while a promotional advertisement for Foster's Home for Imaginary Friends featured one of its lead characters, Coco, performing the dance before destroying the set around her.

The Cancan tune is used as the Star Power theme in Super Mario Land. Science Bloggers AsapScience made a Periodic Table Song sung to the tune, intending to help kids and students memorize and learn about the chemical elements.  In 2022, urbanist blogger Alex Davis made a song explaining the fare system of NJ Transit.

References

Erotic dance
French dances
The Muppets songs
Moulin Rouge
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Germaine Hesus "Kemy" Agustien (born 20 August 1986) is a Curaçaoan professional footballer who plays as a central midfielder.

He previously played for Willem II, AZ Alkmaar, Roda JC and RKC Waalwijk, for Birmingham City, Crystal Palace, Swansea City and Brighton & Hove Albion in English football, for Danish club Vendsyssel FF, for Scottish club Hamilton Academical. and for Global Cebu in the Philippines. An adaptable player, capable of playing anywhere in midfield, his preferred position is as one of two central midfielders.

Club career
Born in Willemstad, Netherlands Antilles, Agustien began his career in the youth system of Dutch club Willem II. He played two seasons in that club's first team in the Eredivisie, and appeared twice in the 2005–06 UEFA Cup. He signed for AZ in 2006, and was loaned to Roda JC for the 2006–07 season to gain more experience.

Agustien joined English Championship club Birmingham City in July 2008 on a season loan, with an option to make the deal permanent at the end of the 2008–09 season for a fee of €2 million. He made his first-team debut in the League Cup defeat at Southampton on 26 August 2008, and played his first match in the Football League four days later in a 1–1 draw at Norwich City. Having missed pre-season training because of a hernia operation, he did not adapt immediately to the pace and physicality of English football. He played 20 games in all competitions, but the second half of his season was dogged by injury. Birmingham manager Alex McLeish "couldn't commit [himself] to bringing him in for the money asked", so Agustien returned to AZ when his contract expired on 26 May 2009.

After his return to AZ, he was loaned to RKC Waalwijk, newly promoted to the Eredivisie, for the 2009–10 season. At the end of that season, he was released by AZ.

Agustien went on trial to Polish Ekstraklasa side Wisła Kraków in July 2010. Later he joined Swansea City of the English Championship on trial, but sustained an injury in a pre-season match which delayed his signing. After passing what was described as a "tough" medical, Agustien signed a two-year contract with the Welsh club in October. He made his debut two weeks later, coming on for  Andrea Orlandi after 69 minutes as Swansea beat Leicester City 2–0.

By February 2011, Agustien was anxious for regular first-team football, and suggested that there had been interest from clubs in taking him on loan, but manager Brendan Rodgers considered him part of the Swansea squad. Agustien signed on loan for Crystal Palace on 8 March for the rest of the season. He made his debut against Barnsley in a 2–1 victory for Palace.

He made his Premier League debut for the newly promoted Swansea in a 4–0 loss against Manchester City, but suffered a hamstring injury in September, and was restricted to one brief substitute appearance in the next three months. In the 1–1 draw with Queens Park Rangers at the end of December, Agustien started in central midfield, but following an injury to Àngel Rangel he spent the second half at right back, a position he had never played before; he was named man of the match:

Ankle surgery in early March revealed further problems that kept Agustien out for the remainder of the season. Rodgers confirmed that Agustien would be offered a contract extension despite his injuries, and in May he signed a new two-year deal with Swansea. In the 2012–13 season was a big change for Swansea City, with change of management and new players. For Agustien, his injuries continued to haunt him, having missed five matches, due to an ankle injury.

Ahead of the 2013–14 season, Agustien, along with Alan Tate, Luke Moore and Leroy Lita, was left out of the squad for the pre-season tour, which led their future uncertain. During July 2013, Agustien transferred to Championship club Brighton & Hove Albion signing a two-year contract, however the deal was delayed for a number of days whilst awaiting international clearance which was finally completed on 1 August. Agustien made his debut for Brighton during a pre-season friendly game against Norwich City which finished 1–1. He made 14 appearances in all competitions in his first season, but only 3 in his second, which was disrupted by injury. He was released when his contract expired at the end of the 2014–15 season.

On 25 September 2015, it was announced that Agustien had signed a contract with the Danish 1st Division side Vendsyssel FF until the end of the year. Wearing number 13, the player was struck by injuries and his contract was not extended when it expired on 1 January 2016.

In March 2016 he signed for Scottish club Hamilton Academical. In May 2016 it was announced that he would leave Hamilton at the end of the 2015–16 season.

Agustien returned to Dutch football for 2016–17, signing a one-year contract with Eerste Divisie club FC Dordrecht. He was released by the club on 15 November 2016. Following his release from the club, Agustien signed with Filipino club Global F.C., playing in the Philippines Football League.

Agustien signed for English National League North club Nuneaton Borough on 27 June 2018, but left again by mutual consent before the season started. He played twice for Halesowen Town of the Southern League on a non-contract basis, then trained with and appeared as an over-age player for Birmingham City's under-23 team, before joining National League club Barrow on 15 November on a short-term contract. He scored twice from 11 appearances in all competitions, and then left the club when a contract extension could not be agreed.

On 21 March 2019, Agustien signed for another National League club, Wrexham, until the end of the season. He made three appearances before being released when his contract expired. He signed for Bradford (Park Avenue) of the National League North in late September 2019, and went straight into the starting eleven for their visit to Brackley Town. He was substituted after 57 minutes with his team down to ten men and losing 5–0; the final score was 8–0.

On 30 January 2020 he signed for Mickleover Sports.

On 12 October 2022, Agustien returned to the National League North when he signed for Kettering Town.

On 2 December 2022, Agustien joined Southern League Premier Division Central side Hednesford Town. In June 2023, he joined Northern Premier League Premier Division club Matlock Town, leaving the club in September 2023.

International career
At international level, he was a member of the Netherlands under-20 squad for the 2005 FIFA World Youth Championship, where he played in two of the group-stage matches. He played for the Dutch Olympic squad that reached the final of the 2006 Toulon Tournament; Agustien converted his penalty as his team lost in a penalty shootout. He played again, and scored, at the 2007 edition, and also played for the under-21 team, including two appearances in qualifying matches for the 2009 European under-21 championships. Named in the Netherlands' preliminary 37-man squad for the 2008 Olympics, he was not selected for Beijing.

In 2014, Agustien decided to represent his country of birth, receiving his first call-up for the Curaçao senior team ahead of the 2014 Caribbean Cup in Jamaica. He was however forced to withdraw from the final squad for the tournament due to injury, having yet to make his debut for the national team. He made his debut for Curaçao 6 June 2015 in a friendly match against Trinidad and Tobago which ended in a 1–0 win at home.

Personal life
Agustien revealed he almost died from a serious car accident after his car flipped twice following a loss of control. In April 2013, Agustien was banned from driving for 12 months and picked up 39 points.

Career statistics

International statistics

Honours

Club
Swansea City
League Cup: 2012–13

International
Curaçao
 Caribbean Cup: 2017

References

External links

 Holland stats at OnsOranje

1986 births
Living people
Footballers from Willemstad
Men's association football midfielders
Curaçao men's footballers
Curaçao men's international footballers
Dutch men's footballers
Netherlands men's youth international footballers
Netherlands men's under-21 international footballers
Willem II (football club) players
AZ Alkmaar players
Roda JC Kerkrade players
Birmingham City F.C. players
RKC Waalwijk players
Swansea City A.F.C. players
Brighton & Hove Albion F.C. players
Crystal Palace F.C. players
Vendsyssel FF players
Hamilton Academical F.C. players
FC Dordrecht players
Global F.C. players
SV TEC players
Nuneaton Borough F.C. players
Halesowen Town F.C. players
Barrow A.F.C. players
Wrexham A.F.C. players
Bradford (Park Avenue) A.F.C. players
Mickleover F.C. players
Kettering Town F.C. players
Hednesford Town F.C. players
Matlock Town F.C. players
Eredivisie players
English Football League players
Premier League players
Scottish Professional Football League players
Southern Football League players
National League (English football) players
Northern Premier League players
2017 CONCACAF Gold Cup players
Dutch people of Curaçao descent
Dutch expatriate men's footballers
Expatriate men's footballers in England
Expatriate men's footballers in Wales
Expatriate men's footballers in Scotland
Expatriate men's footballers in Denmark
Expatriate men's footballers in the Philippines
Dutch expatriate sportspeople in England
Dutch expatriate sportspeople in Wales
Dutch expatriate sportspeople in Scotland
Dutch expatriate sportspeople in Denmark
Dutch expatriate sportspeople in the Philippines
Philippines Football League players

Kemy Agustien


The Inspiration of Saint Matthew (1602) is a painting by the Italian Baroque master Michelangelo Merisi da Caravaggio. Commissioned by the French Cardinal Matteo Contarelli, the canvas hangs in Contarelli chapel altar in the church of the French congregation San Luigi dei Francesi in Rome, Italy.

It is one of three Caravaggio canvases in the chapel: hanging between the larger earlier canvases of The Martyrdom of Saint Matthew, and The Calling of Saint Matthew. This was not an easy commission for Caravaggio, and at least two of the three paintings had to be either replaced or repainted to satisfy his patron, the Cardinal Del Monte.

Creation
In February 1602, following the installation of his first two pieces in the chapel, Caravaggio was contracted to create an altarpiece, to be delivered by Pentecost of that year. The first painting he created, Saint Matthew and the Angel, was rejected and later destroyed in World War II.

The Inspiration of Saint Matthew was finished rather quickly, with Caravaggio receiving payment by September 1602.

Description
In the work featured on the altar, the angel belongs to an aerial and sublime dimension, enveloped in an encircling rippled sheet. The restless Matthew leans to work, as the angel enumerates for him the work to come. All is darkness but for the two large figures. Matthew appears to have rushed to his desk, his stool teetering into our space. His expression is sober.

See also
List of paintings by Caravaggio

Further reading
 Jürgen Müller, Das geöffnete Buch. Caravaggios Altargemälde 'Die Inspiration des Evangelisten Matthäus durch den Engel' in der Contarelli-Kapelle und die Laienlektüre der Bibel, in: Kunstgeschichte. Open Peer Reviewed Journal, 2021

References

External links

Paintings by Caravaggio
Artworks in San Luigi dei Francesi
1602 paintings
Religious paintings
Angels in art
Paintings depicting Matthew the Apostle
Books in art
Altarpieces

The Inspiration of Saint Matthew


Marco Berthelot (born December 11, 1972 in Murdochville, Quebec) is a Canadian curler from Longueuil, Quebec.

After playing lead for Michel Ferland at the 1991 Canadian Junior Curling Championships, Berthelot would be bumped up to third on Ferland's team and they won the 1992 Canadian Juniors. This qualified them for the 1993 World Junior Curling Championships where they won a silver medal - losing to Scotland (skipped by Craig Wilson) in the final.

Berthelot played at the 2000 and 2001 Canadian Mixed Curling Championship at second position for Jean-Michel Ménard and won in 2001.

In 2006, Berthelot joined up with Pierre Charette and Berthelot won his first Quebec men's provincial championship in 2007. His last provincial championship appearance was in 2009 playing for Martin Ferland where they lost in the final.

Berthelot is currently the General Manager for Curling Quebec.

External links

1972 births
Living people
People from Gaspésie–Îles-de-la-Madeleine
Sportspeople from Longueuil
Curlers from Quebec
Canadian mixed curling champions

Marco Berthelot


Established in 1993 by Ludwig Cancer Research and McGill University (Montreal, Canada), the Ludwig / McGill Cohort is one of the world's largest longitudinal studies of the natural history of human papillomavirus (HPV) infection and cervical cancer risk.

 The Ludwig / McGill Cohort provided pap cytology and HPV testing for 2,528 low income women in São Paulo, Brazil, a city with one of the highest risks for cervical cancer worldwide. Some of these women have been monitored clinically for more than 10 years.
 This international collaboration contributed data critical for the design and development of vaccines against HPV.
 LICR São Paulo Branch Director, and co-founder of the Ludwig / McGill Cohort, Dr. Luisa L. Villa, was the lead author of the first study to show efficacy of Merck's HPV vaccine, Gardasil.
 Important findings from the Ludwig / McGill cohort include:
 Diet may decrease the risk of cervical disease. This finding is particularly relevant to the developing world where changes in diet are more feasible and less costly than treating the infection or resultant disease, and
 Different types of HPV are present in different ethnic populations. This critical finding may affect vaccine formulation and efficacy in different parts of the world.

References

Cohort studies
Epidemiological study projects

Ludwig-McGill HPV Cohort


Gulzar Singh Sandhu (born 27 February 1935) is a prominent Punjabi language writer. He won the prestigious Sahitya Akademi Award, given by the Sahitya Akademi, India's National Academy of Letters, for his short story collection, Amar Katha in 1982. Among other awards he was also the recipient of International Association of Authors, Playwrights and Artists of Canada in 1992 and Shiromani Punjabi Sahityakar Puraskar from the Education Department of Punjab in 2001.

Early life and education
He was born on 27 February 1935 in the village of Kotla Badla in Samrala division of Ludhiana district. He has a master's degree and Gyani in Punjabi literature. He was married to Dr. Surjeet Kaur Pannu on 11 March 1966.

Career
He has held various senior posts with the Indian government, Punjab Agricultural University and Indian Red Cross. He taught in Punjabi University as a professor of Journalism and Mass communication. He was also the chief editor of prominent newspapers and the founding editor of The Punjabi Tribune published from Chandigarh. Due to his remarkable contribution to Punjabi literature has been honored with appointments to several educational and literary institutions such as Punjabi writer's academy, Punjabi literary academy and Punjab arts council.

His columns are published regularly in noted Punjabi magazines and newspapers in India and abroad.

Personal life
He is married to Surjit Kaur Sandhu. He lives in Chandigarh, India with his wife.

References

Sources
 Publication Bureau Punjabi University Patiala
 www.sahitya-akademi.gov.in

Punjabi-language writers
Journalists from Punjab, India
1935 births
Living people
People from Ludhiana district
Indian male journalists
Indian columnists
Indian newspaper editors
Academic staff of Punjab Agricultural University
Recipients of the Sahitya Akademi Award in Punjabi
Academic staff of Punjabi University
20th-century Indian journalists

Gulzar Singh Sandhu


Aston is a hamlet in the civil parish of Sudbury in the district of Derbyshire Dales, Derbyshire, England.  It lies at the junction of the A50 and A515 roads.

Aston was mentioned in the Domesday Book as Estun.

Aston Bridge carries the A515 road across the River Dove to Staffordshire.  It is a Grade II listed building.

References

External links

Hamlets in Derbyshire
Derbyshire Dales

Aston, Derbyshire Dales


A material property is an intensive property of a material, i.e., a physical property or chemical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one material versus another can be compared, thereby aiding in materials selection.

A property having a fixed value for a given material or substance is called material constant or constant of matter.
(Material constants should not be confused with physical constants, that have a universal character.)

A material property may also be a function of one or more independent variables, such as temperature. Materials properties often vary to some degree according to the direction in the material in which they are measured, a condition referred to as anisotropy. Materials properties that relate to different physical phenomena often behave linearly (or approximately so) in a given operating range . Modeling them as linear functions can significantly simplify the differential constitutive equations that are used to describe the property.

Equations describing relevant materials properties are often used to predict the attributes of a system.

The properties are measured by standardized test methods. Many such methods have been documented by their respective user communities and published through the Internet; see ASTM International.

Acoustical properties
Acoustical absorption
Speed of sound
Sound reflection
Sound transfer
Third order elasticity (Acoustoelastic effect)

Atomic properties
Atomic mass: (applies to each element) the average mass of the atoms of an element, in daltons (Da), a.k.a. atomic mass units (amu).
Atomic number: (applies to individual atoms or pure elements) the number of protons in each nucleus
Relative atomic mass, a.k.a. atomic weight: (applies to individual isotopes or specific mixtures of isotopes of a given element) (no units)
Standard atomic weight: the average relative atomic mass of a typical sample of the element (no units)

Chemical properties

Corrosion resistance
Hygroscopy
pH
Reactivity
Specific internal surface area
Surface energy
Surface tension

Electrical properties
Capacitance
Dielectric constant
Dielectric strength
Electrical resistivity and conductivity
Electric susceptibility
Electrocaloric coefficient
Electrostriction
Magnetoelectric polarizability
Nernst coefficient (thermoelectric effect)
Permittivity
Piezoelectric constants
Pyroelectricity
Seebeck coefficient

Magnetic properties
Curie temperature
Diamagnetism
Hall coefficient
Hysteresis
Magnetostriction
Magnetocaloric coefficient
Magnetothermoelectric power (magneto-Seebeck effect coefficient)
Magnetoresistance
Maximum energy product
Permeability
Piezomagnetism
Pyromagnetic coefficient
Spin Hall effect

Manufacturing properties
Castability: How easily a high-quality casting can be obtained from the material
Machinability rating
Machining speeds and feeds

Mechanical properties
Brittleness: Ability of a material to break or shatter without significant deformation when under stress; opposite of plasticity, examples: glass, concrete, cast iron, ceramics etc.
Bulk modulus: Ratio of pressure to volumetric compression (GPa) or ratio of the infinitesimal pressure increase to the resulting relative decrease of the volume
Coefficient of restitution: The ratio of the final to initial relative velocity between two objects after they collide. Range: 0–1, 1 for perfectly elastic collision.
Compressive strength: Maximum stress a material can withstand before compressive failure (MPa)
Creep: The slow and gradual deformation of an object with respect to time. If the s in a material exceeds the yield point, the strain caused in the material by the application of load does not disappear totally on the removal of load. The plastic deformation caused to the material is known as creep. At high temperatures, the strain due to creep is quite appreciable.
Density: Mass per unit volume (kg/m^3)
Ductility: Ability of a material to deform under tensile load (% elongation). It is the property of a material by which it can be drawn into wires under the action of tensile force. A ductile material must have a high degree of plasticity and strength so that large deformations can take place without failure or rupture of the material. In ductile extension, a material that exhibits a certain amount of elasticity along with a high degree of plasticity.
Durability: Ability to withstand wear, pressure, or damage; hard-wearing
Elasticity: Ability of a body to resist a distorting influence or stress and to return to its original size and shape when the stress is removed
Fatigue limit: Maximum stress a material can withstand under repeated loading (MPa)
Flexural modulus
Flexural strength: Maximum bending stress a material can withstand before failure (MPa)
Fracture toughness: Ability of a material containing a crack to resist fracture (J/m^2)
Friction coefficient: The amount of force normal to surface which converts to force resisting relative movement of contacting surfaces between material pairs
Hardness: Ability to withstand surface indentation and scratching (e.g. Brinell hardness number)
Malleability: Ability of the material to be flattened into thin sheets under applications of heavy compressive forces without cracking by hot or cold working means.This property of a material allows it to expand in all directions without rupture.
Mass diffusivity: Ability of one substance to diffuse through another
Plasticity: Ability of a material to undergo irreversible or permanent deformations without breaking or rupturing; opposite of brittleness
Poisson's ratio: Ratio of lateral strain to axial strain (no units)
Resilience: Ability of a material to absorb energy when it is deformed elastically (MPa); combination of strength and elasticity
Shear modulus: Ratio of shear stress to shear strain (MPa)
Shear strength: Maximum shear stress a material can withstand
Slip: A tendency of a material's particles to undergo plastic deformation due to a dislocation motion within the material. Common in Crystals.
Specific modulus: Modulus per unit volume (MPa/m^3)
Specific strength: Strength per unit density (Nm/kg)
Specific weight: Weight per unit volume (N/m^3)
Surface roughness: The deviations in the direction of the normal vector of a real surface from its ideal form
Tensile strength: Maximum tensile stress of a material can withstand before failure (MPa)
Toughness: Ability of a material to absorb energy (or withstand shock) and plastically deform without fracturing (or rupturing); a material's resistance to fracture when stressed; combination of strength and plasticity
Viscosity: A fluid's resistance to gradual deformation by tensile or shear stress; thickness
Yield strength: The stress at which a material starts to yield plastically (MPa)
Young's modulus: Ratio of linear stress to linear strain (MPa) (influences the stiffness and flexibility of an object)

Optical properties

Absorbance: How strongly a chemical attenuates light
Birefringence
Color
Electro-optic effect
Luminosity
Optical activity
Photoelasticity
Photosensitivity
Reflectivity
Refractive index
Scattering
Transmittance

Radiological properties
Attenuation coefficients
Half-life
Neutron cross section
Specific activity

Thermal properties
Phase diagram
Boiling point
Coefficient of thermal expansion
Critical temperature
Curie point
Ductile-to-brittle transition temperature
Emissivity
Eutectic point
Flammability
Flash point
Glass transition temperature
Heat of vaporization
Inversion temperature
Melting point
Thermal conductivity
Thermal diffusivity
Thermal expansion
Triple point
Vapor pressure
Specific heat capacity

See also
Physical property
Strength of materials
Supervenience
List of thermodynamic properties

References

Chemical properties
Materials science
Physical quantities

List of materials properties