Corporal punishment or physical punishment is a punishment intended to cause physical pain on a person. It is most practised on minors in home and school settings. Common methods include paddling, it has historically been used on adults on prisoners and enslaved people. Other common methods include caning. Official punishment for crime by inflicting pain or injury, including flogging and mutilation, was practised in most civilizations since ancient times. However, with the growth of humanitarian ideals since the Enlightenment, such punishments were viewed as inhumane. By the late 20th century, corporal punishment had been eliminated from the legal systems of most developed countries; the legality in the 21st century of corporal punishment in various settings differs by jurisdiction. Internationally, the late 20th century and early 21st century saw the application of human rights law to the question of corporal punishment in a number of contexts: Corporal punishment in the home, punishment of children or teenagers by parents or other adult guardians, is legal in most of the world.
58 countries, most of them in Europe and Latin America, have banned the practice as of 2018. School corporal punishment, of students by teachers or school administrators, has been banned in many countries, including Canada, South Africa, New Zealand and all of Europe, it remains legal, if less common, in some states of the United States. Judicial corporal punishment, as part of a criminal sentence ordered by a court of law, has long disappeared from European countries. However, as of November 2017, it remains lawful in parts of Africa, the Anglophone Caribbean and indigenous communities of Ecuador and Colombia. Related is prison corporal punishment or disciplinary corporal punishment, ordered by prison authorities or carried out directly by staff. Corporal punishment is allowed in some military settings in a few jurisdictions. Other uses of corporal punishment have existed, for instance, as once practised on apprentices by their masters. In many Western countries and human-rights organizations oppose corporal punishment of children.
Campaigns against corporal punishment have aimed to bring about legal reform to ban the use of corporal punishment against minors in homes and schools. Author Jared Diamond writes that hunter-gatherer societies have tended to use little corporal punishment whereas agricultural and industrial societies tend to use progressively more of it. Diamond suggests this may be because hunter-gatherers tend to have few valuable physical possessions, misbehavior of the child would not cause harm to others' property. Researchers living among the Parakanã and Ju/’hoansi people, as well as among some Aboriginal Australians, have written of the absence of physical punishment of children in those cultures. Wilson writes: Probably the only generalization that can be made about the use of physical punishment among primitive tribes is that there was no common procedure Pettit concludes that among primitive societies corporal punishment is rare, not because of the innate kindliness of these people but because it is contrary to developing the type of individual personality they set up as their ideal An important point to be made here is that we cannot state that physical punishment as a motivational or corrective device is'innate' to man.
Corporal punishment of children has traditionally been used in the Western world by adults in authority roles. Beating one's child as a punishment was recommended as early as the c. 10th century BC book of Proverbs attributed to Solomon: He that spareth the rod, hateth his son. A fool's lips enter into contention, his mouth calleth for strokes. Chasten thy son while there is hope, let not thy soul spare for his crying. Judgements are prepared for scorners, stripes for the backs of fools. Foolishness is bound in the heart of a child. Withhold not correction from the child. A whip for a horse, a bridle for an ass, a rod for a fool's back. Robert McCole Wilson argues, "Probably this attitude comes, at least in part, from the desire in the patriarchal society for the elder to maintain his authority, where that authority was the main agent for social stability, but these are the words that not only justified the use of physical punishment on children for over a thousand years in Christian communities, but ordered it to be used.
The words were accepted with but few exceptions. Curiously, the gentleness of Christ towards children was ignored". Corporal punishment was used in Egypt, China and Rome for both judicial and educational discipline. Disfigured Egyptian criminals were exiled to the Sinai border at Tjaru and Rhinocorura, whose own name meant "cut-off noses". China disfigured some criminals and tattooed others; some states gained a reputation for using such punishments cruelly. Although the Spartan example was extreme, corporal punishment was the most frequent type of punishment. In the Roman Empire, the maximum penalty that a Roman citizen could receive under the law was 40 "lashes" or "strokes" with a whip applied to the back and shoulders, or with the "fasces" (similar to a birch rod, but consisting of 8–10 lengths of willow r
Cambridge University Press
Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the world's oldest publishing house and the second-largest university press in the world, it holds letters patent as the Queen's Printer. The press mission is "to further the University's mission by disseminating knowledge in the pursuit of education and research at the highest international levels of excellence". Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. With a global sales presence, publishing hubs, offices in more than 40 countries, it publishes over 50,000 titles by authors from over 100 countries, its publishing includes academic journals, reference works and English language teaching and learning publications. Cambridge University Press is a charitable enterprise that transfers part of its annual surplus back to the university. Cambridge University Press is both the oldest publishing house in the world and the oldest university press.
It originated from letters patent granted to the University of Cambridge by Henry VIII in 1534, has been producing books continuously since the first University Press book was printed. Cambridge is one of the two privileged presses. Authors published by Cambridge have included John Milton, William Harvey, Isaac Newton, Bertrand Russell, Stephen Hawking. University printing began in Cambridge when the first practising University Printer, Thomas Thomas, set up a printing house on the site of what became the Senate House lawn – a few yards from where the press's bookshop now stands. In those days, the Stationers' Company in London jealously guarded its monopoly of printing, which explains the delay between the date of the university's letters patent and the printing of the first book. In 1591, Thomas's successor, John Legate, printed the first Cambridge Bible, an octavo edition of the popular Geneva Bible; the London Stationers objected strenuously. The university's response was to point out the provision in its charter to print "all manner of books".
Thus began the press's tradition of publishing the Bible, a tradition that has endured for over four centuries, beginning with the Geneva Bible, continuing with the Authorized Version, the Revised Version, the New English Bible and the Revised English Bible. The restrictions and compromises forced upon Cambridge by the dispute with the London Stationers did not come to an end until the scholar Richard Bentley was given the power to set up a'new-style press' in 1696. In July 1697 the Duke of Somerset made a loan of £200 to the university "towards the printing house and presse" and James Halman, Registrary of the University, lent £100 for the same purpose, it was in Bentley's time, in 1698, that a body of senior scholars was appointed to be responsible to the university for the press's affairs. The Press Syndicate's publishing committee still meets and its role still includes the review and approval of the press's planned output. John Baskerville became University Printer in the mid-eighteenth century.
Baskerville's concern was the production of the finest possible books using his own type-design and printing techniques. Baskerville wrote, "The importance of the work demands all my attention. Caxton would have found nothing to surprise him if he had walked into the press's printing house in the eighteenth century: all the type was still being set by hand. A technological breakthrough was badly needed, it came when Lord Stanhope perfected the making of stereotype plates; this involved making a mould of the whole surface of a page of type and casting plates from that mould. The press was the first to use this technique, in 1805 produced the technically successful and much-reprinted Cambridge Stereotype Bible. By the 1850s the press was using steam-powered machine presses, employing two to three hundred people, occupying several buildings in the Silver Street and Mill Lane area, including the one that the press still occupies, the Pitt Building, built for the press and in honour of William Pitt the Younger.
Under the stewardship of C. J. Clay, University Printer from 1854 to 1882, the press increased the size and scale of its academic and educational publishing operation. An important factor in this increase was the inauguration of its list of schoolbooks. During Clay's administration, the press undertook a sizeable co-publishing venture with Oxford: the Revised Version of the Bible, begun in 1870 and completed in 1885, it was in this period as well that the Syndics of the press turned down what became the Oxford English Dictionary—a proposal for, brought to Cambridge by James Murray before he turned to Oxford. The appointment of R. T. Wright as Secretary of the Press Syndicate in 1892 marked the beginning of the press's development as a modern publishing business with a defined editorial policy and administrative structure, it was Wright who devised the plan for one of the most distinctive Cambridge contributions to publishing—the Cambridge Histories. The Cambridge Modern History was published
Encyclopædia Britannica, Eleventh Edition
The Encyclopædia Britannica, Eleventh Edition is a 29-volume reference work, an edition of the Encyclopædia Britannica. It was developed during the encyclopaedia's transition from a British to an American publication; some of its articles were written by the best-known scholars of the time. This edition of the encyclopedia, containing 40,000 entries, is now in the public domain, many of its articles have been used as a basis for articles in Wikipedia. However, the outdated nature of some of its content makes its use as a source for modern scholarship problematic; some articles have special value and interest to modern scholars as cultural artifacts of the 19th and early 20th centuries. The 1911 eleventh edition was assembled with the management of American publisher Horace Everett Hooper. Hugh Chisholm, who had edited the previous edition, was appointed editor in chief, with Walter Alison Phillips as his principal assistant editor. Hooper bought the rights to the 25-volume 9th edition and persuaded the British newspaper The Times to issue its reprint, with eleven additional volumes as the tenth edition, published in 1902.
Hooper's association with The Times ceased in 1909, he negotiated with the Cambridge University Press to publish the 29-volume eleventh edition. Though it is perceived as a quintessentially British work, the eleventh edition had substantial American influences, not only in the increased amount of American and Canadian content, but in the efforts made to make it more popular. American marketing methods assisted sales; some 14% of the contributors were from North America, a New York office was established to coordinate their work. The initials of the encyclopedia's contributors appear at the end of selected articles or at the end of a section in the case of longer articles, such as that on China, a key is given in each volume to these initials; some articles were written by the best-known scholars of the time, such as Edmund Gosse, J. B. Bury, Algernon Charles Swinburne, John Muir, Peter Kropotkin, T. H. Huxley, James Hopwood Jeans and William Michael Rossetti. Among the lesser-known contributors were some who would become distinguished, such as Ernest Rutherford and Bertrand Russell.
Many articles were carried over from some with minimal updating. Some of the book-length articles were divided into smaller parts for easier reference, yet others much abridged; the best-known authors contributed only a single article or part of an article. Most of the work was done by British Museum scholars and other scholars; the 1911 edition was the first edition of the encyclopædia to include more than just a handful of female contributors, with 34 women contributing articles to the edition. The eleventh edition introduced a number of changes of the format of the Britannica, it was the first to be published complete, instead of the previous method of volumes being released as they were ready. The print type was subject to continual updating until publication, it was the first edition of Britannica to be issued with a comprehensive index volume in, added a categorical index, where like topics were listed. It was the first not to include long treatise-length articles. Though the overall length of the work was about the same as that of its predecessor, the number of articles had increased from 17,000 to 40,000.
It was the first edition of Britannica to include biographies of living people. Sixteen maps of the famous 9th edition of Stielers Handatlas were translated to English, converted to Imperial units, printed in Gotha, Germany by Justus Perthes and became part this edition. Editions only included Perthes' great maps as low quality reproductions. According to Coleman and Simmons, the content of the encyclopedia was distributed as follows: Hooper sold the rights to Sears Roebuck of Chicago in 1920, completing the Britannica's transition to becoming a American publication. In 1922, an additional three volumes, were published, covering the events of the intervening years, including World War I. These, together with a reprint of the eleventh edition, formed the twelfth edition of the work. A similar thirteenth edition, consisting of three volumes plus a reprint of the twelfth edition, was published in 1926, so the twelfth and thirteenth editions were related to the eleventh edition and shared much of the same content.
However, it became apparent that a more thorough update of the work was required. The fourteenth edition, published in 1929, was revised, with much text eliminated or abridged to make room for new topics; the eleventh edition was the basis of every version of the Encyclopædia Britannica until the new fifteenth edition was published in 1974, using modern information presentation. The eleventh edition's articles are still of value and interest to modern readers and scholars as a cultural artifact: the British Empire was at its maximum, imperialism was unchallenged, much of the world was still ruled by monarchs, the tragedy of the modern world wars was still in the future, they are an invaluable resource for topics omitted from modern encyclopedias for biography and the history of science and technology. As a literary text, the encyclopedia has value as an example of early 20th-century prose. For example, it employs literary devices, such as pathetic fallacy, which are not as common in modern reference texts.
In 1917, using the pseudonym of S. S. Van Dine, the US art critic and author Willard Huntington Wright published Misinforming a Nation, a 200+
The S3 Virtual Reality Graphics Engine graphics chipset was one of the first 2D/3D accelerators designed for the mass market. Introduced in 1995 by graphics powerhouse S3, Inc. the ViRGE was S3's first foray into 3D-graphics. The S3/Virge was the successor to the successful Trio64V+. ViRGE/325 was pin compatible with the Trio64 chip, retaining the DRAM-framebuffer interface, clocking both the core and memory up to 80 MHz. In Windows, Virge was benchmarked as the fastest DRAM-based accelerator of the era; the VRAM-based version, ViRGE/VX, was slower in lower resolutions, but had a faster RAMDAC to support high-resolution modes not available on the 325. Part of S3's marketing plan for the ViRGE included the "S3D" standard, stating that members of the ViRGE family carried the S3D Graphics Engine. Games that supported ViRGE directly put this logo on their box so owners of the 3D card would know that it would run as well as possible on their computer. And, despite its lackluster 3D-speed, the ViRGE did receive some S3D enhanced games, due in large part to the brand prestige S3 carried in this period: ViRGE-enhanced versions of Terminal Velocity, Descent II, Monster Truck Madness, Tomb Raider, MechWarrior 2 and Jedi Knight.
With the successful launch of the Sony PlayStation home game-console, pressure was on the PC market to incorporate hardware that could compete in the area of realtime 3D graphics rendering, something that software-based host-CPU rendering could not do on its own. That is, main-CPU software-based rendering could render realtime 3D graphics—as demonstrated by games like Descent, which used only the main CPU and standard VGA hardware to render full-screen 3D video with 6-degrees-of-freedom motion in real time—but the resolution, polygon count, quality of shading, etc. were not competitive with dedicated 3D rendering hardware. While the market demand was present, realtime 3D graphics rendering was new and unfamiliar territory for S3 and many of its hardware competitors. With a sizable chunk of ViRGE's hardware real-estate devoted to other key functions, the need to serve traditional 2D applications, the resulting 3D functionality was both limited and slow; when performing basic 3D-rendering with only texture mapping and no other advanced features, ViRGE's pixel throughput was somewhat faster than the best software-optimized 3D-rendering of the era, with better color fidelity.
But when additional rendering operations were added to the polygon load, rendering throughput dropped to the speed of software-based rendering on an entry-level CPU. 3D-rendering on the high-end VRAM based ViRGE/VX was slower than the less expensive ViRGE/325, due to the VX's slower core and memory clock rates. The upgraded ViRGE/DX and ViRGE/GX models did improve 3D rendering performance, but by the time of their introduction they were still unable to distinguish the ViRGE family in an crowded 3D market. Outside of 3D rendering, ViRGE was a solid performer in familiar tasks as DOS VGA and Microsoft Windows. Here, S3's substantial experience in high-performance Windows acceleration showed, with ViRGE benchmarking near the top among competing DRAM-based VGA cards. In OEM PC markets, ViRGE sold well as a direct replacement to S3's successful Trio/64 family; the ViRGE family delivered faster Windows acceleration in the same physical footprint as its predecessor. The introduction of competing hardware, 3dfx's Voodoo Graphics and Rendition's Verité, game titles such as Id Software's popular Quake engine, resulted in an industry-wide shakeout.
S3, along with other well-established VGA vendors in the PC market, were unable to adapt to the evolving PC 3D graphics market, being relegated to sell into market segments where 3D graphics functionality was unimportant. Although the ViRGE sold well in the OEM market, poor Direct3D performance and lack of OpenGL support prevented the ViRGE from competing in the more lucrative 3D graphics segment. Between its birth in 1995 and retirement near the year 2000, the ViRGE family received regular upgrades; the ViRGE/DX boosted the performance of the original ViRGE/325 by improving perspective correction and implementing a full-speed trilinear filter. The ViRGE/GX added support for more modern SD/SGRAM; the ViRGE/GX2 was one of the first VGA chipsets to support AGP, although the level of support extended little beyond electrical compliance. Substantial use of AGP's feature-set would have to wait until the Savage 3D; the ViRGE was replaced by the Savage 3D in S3's top-end graphics segment in 1998. However, at least one derivative of the ViRGE remained in production after the discontinuation of the Savage 3D.
64-bit 2D/3D graphics S3d Engine with integrated 135 MHz, 170 MHz or 220 MHz RAMDAC and clock synthesizer S3 Streams Processor for accelerated video On-the-fly stretching and blending of primary RGB stream and RGB or YUV secondary stream Each stream can have a different color depth Hardware-assisted video playback with horizontal interpolation Support for Indeo and software and hardware-accelerated MPEG-1 video S3 Scenic Highway for direct interface to live video and MPEG-1 peripherals 2D GUI acceleration. 3D texture mapping Perspective correction and Gouraud shading. ViRGE/DX and feature'parallel processing' perspective correction for better performance Bilinear and trilinear texture filtering, MIP Mapping, alpha blending, video texture mapping. Trilinear filtering is full-speed on ViRGE/DX and termed'SmartFilter' technology. Depth cuei
A cylinder has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. It is the idealized version of a solid physical tin can having lids on bottom; this traditional view is still used in elementary treatments of geometry, but the advanced mathematical viewpoint has shifted to the infinite curvilinear surface and this is how a cylinder is now defined in various modern branches of geometry and topology. The shift in the basic meaning has created some ambiguity with terminology, it is hoped that context makes the meaning clear. In this article both points of view are presented and distinguished by referring to solid cylinders and cylindrical surfaces, but keep in mind that in the literature the unadorned term cylinder could refer to either of these or to an more specialized object, the right circular cylinder; the definitions and results in this section are taken from the 1913 text and Solid Geometry by George Wentworth and David Eugene Smith. A cylindrical surface is a surface consisting of all the points on all the lines which are parallel to a given line and which pass through a fixed plane curve in a plane not parallel to the given line.
Any line in this family of parallel lines is called an element of the cylindrical surface. From a kinematics point of view, given a plane curve, called the directrix, a cylindrical surface is that surface traced out by a line, called the generatrix, not in the plane of the directrix, moving parallel to itself and always passing through the directrix. Any particular position of the generatrix is an element of the cylindrical surface. A solid bounded by a cylindrical surface and two parallel planes is called a cylinder; the line segments determined by an element of the cylindrical surface between the two parallel planes is called an element of the cylinder. All the elements of a cylinder have equal lengths; the region bounded by the cylindrical surface in either of the parallel planes is called a base of the cylinder. The two bases of a cylinder are congruent figures. If the elements of the cylinder are perpendicular to the planes containing the bases, the cylinder is a right cylinder, otherwise it is called an oblique cylinder.
If the bases are disks the cylinder is called a circular cylinder. In some elementary treatments, a cylinder always means a circular cylinder; the height of a cylinder is the perpendicular distance between its bases. The cylinder obtained by rotating a line segment about a fixed line that it is parallel to is a cylinder of revolution. A cylinder of revolution is a right circular cylinder; the height of a cylinder of revolution is the length of the generating line segment. The line that the segment is revolved about is called the axis of the cylinder and it passes through the centers of the two bases; the bare term cylinder refers to a solid cylinder with circular ends perpendicular to the axis, that is, a right circular cylinder, as shown in the figure. The cylindrical surface without the ends is called an open cylinder; the formulae for the surface area and the volume of a right circular cylinder have been known from early antiquity. A right circular cylinder can be thought of as the solid of revolution generated by rotating a rectangle about one of its sides.
These cylinders are used in an integration technique for obtaining volumes of solids of revolution. A cylindric section is the intersection of a cylinder's surface with a plane, they are, in general and are special types of plane sections. The cylindric section by a plane that contains two elements of a cylinder is a parallelogram; such a cylindric section of a right cylinder is a rectangle. A cylindric section in which the intersecting plane intersects and is perpendicular to all the elements of the cylinder is called a right section. If a right section of a cylinder is a circle the cylinder is a circular cylinder. In more generality, if a right section of a cylinder is a conic section the solid cylinder is said to be parabolic, elliptic or hyperbolic respectively. For a right circular cylinder, there are several ways. First, consider planes that intersect a base in at most one point. A plane is tangent to the cylinder; the right sections are circles and all other planes intersect the cylindrical surface in an ellipse.
If a plane intersects a base of the cylinder in two points the line segment joining these points is part of the cylindric section. If such a plane contains two elements, it has a rectangle as a cylindric section, otherwise the sides of the cylindric section are portions of an ellipse. If a plane contains more than two points of a base, it contains the entire base and the cylindric section is a circle. In the case of a right circular cylinder with a cylindric section, an ellipse, the eccentricity e of the cylindric section and semi-major axis a of the cylindric section depend on the radius of the cylinder r and the angle α between the secant plane and cylinder axis, in the following way: e = cos α, a = r sin α. If the base of a circular cylinder has a radius r and the cylinder has height h its volume is given by V = πr2h; this formula holds. This formula may be established by using Cavalieri's principle. In more generality, by the same principle, the volume of an
The public domain consists of all the creative works to which no exclusive intellectual property rights apply. Those rights may have been forfeited, expressly waived, or may be inapplicable; the works of William Shakespeare and Beethoven, most early silent films, are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by copyright, are therefore in the public domain—among them the formulae of Newtonian physics, cooking recipes, all computer software created prior to 1974. Other works are dedicated by their authors to the public domain; the term public domain is not applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as "under license" or "with permission". As rights vary by country and jurisdiction, a work may be subject to rights in one country and be in the public domain in another; some rights depend on registrations on a country-by-country basis, the absence of registration in a particular country, if required, gives rise to public-domain status for a work in that country.
The term public domain may be interchangeably used with other imprecise or undefined terms such as the "public sphere" or "commons", including concepts such as the "commons of the mind", the "intellectual commons", the "information commons". Although the term "domain" did not come into use until the mid-18th century, the concept "can be traced back to the ancient Roman Law, as a preset system included in the property right system." The Romans had a large proprietary rights system where they defined "many things that cannot be owned" as res nullius, res communes, res publicae and res universitatis. The term res nullius was defined as things not yet appropriated; the term res communes was defined as "things that could be enjoyed by mankind, such as air and ocean." The term res publicae referred to things that were shared by all citizens, the term res universitatis meant things that were owned by the municipalities of Rome. When looking at it from a historical perspective, one could say the construction of the idea of "public domain" sprouted from the concepts of res communes, res publicae, res universitatis in early Roman law.
When the first early copyright law was first established in Britain with the Statute of Anne in 1710, public domain did not appear. However, similar concepts were developed by French jurists in the 18th century. Instead of "public domain", they used terms such as publici juris or propriété publique to describe works that were not covered by copyright law; the phrase "fall in the public domain" can be traced to mid-19th century France to describe the end of copyright term. The French poet Alfred de Vigny equated the expiration of copyright with a work falling "into the sink hole of public domain" and if the public domain receives any attention from intellectual property lawyers it is still treated as little more than that, left when intellectual property rights, such as copyright and trademarks, expire or are abandoned. In this historical context Paul Torremans describes copyright as a, "little coral reef of private right jutting up from the ocean of the public domain." Copyright law differs by country, the American legal scholar Pamela Samuelson has described the public domain as being "different sizes at different times in different countries".
Definitions of the boundaries of the public domain in relation to copyright, or intellectual property more regard the public domain as a negative space. According to James Boyle this definition underlines common usage of the term public domain and equates the public domain to public property and works in copyright to private property. However, the usage of the term public domain can be more granular, including for example uses of works in copyright permitted by copyright exceptions; such a definition regards work in copyright as private property subject to fair-use rights and limitation on ownership. A conceptual definition comes from Lange, who focused on what the public domain should be: "it should be a place of sanctuary for individual creative expression, a sanctuary conferring affirmative protection against the forces of private appropriation that threatened such expression". Patterson and Lindberg described the public domain not as a "territory", but rather as a concept: "here are certain materials – the air we breathe, rain, life, thoughts, ideas, numbers – not subject to private ownership.
The materials that compose our cultural heritage must be free for all living to use no less than matter necessary for biological survival." The term public domain may be interchangeably used with other imprecise or undefined terms such as the "public sphere" or "commons", including concepts such as the "commons of the mind", the "intellectual commons", the "information commons". A public-domain book is a book with no copyright, a book, created without a license, or a book where its copyrights expired or have been forfeited. In most countries the term of protection of copyright lasts until January first, 70 years after the death of the latest living author; the longest copyright term is in Mexico, which has life plus 100 years for all deaths since July 1928. A notable exception is the United States, where every book and tale published prior to 1924 is in the public domain.
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material, a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves, it conveys water and nutrients between the leaves, other growing tissues, the roots. Wood may refer to other plant materials with comparable properties, to material engineered from wood, or wood chips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons and paper. More it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate.
As of 2005, the growing stock of forests worldwide was about 434 billion cubic meters, 47% of, commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991 3.5 billion cubic meters of wood were harvested. Dominant uses were for building construction. A 2011 discovery in the Canadian province of New Brunswick yielded the earliest known plants to have grown wood 395 to 400 million years ago. Wood can be dated by carbon dating and in some species by dendrochronology to determine when a wooden object was created. People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses, weapons, packaging and paper. Known constructions using wood date back ten thousand years. Buildings like the European Neolithic long house were made of wood. Recent use of wood has been enhanced by the addition of bronze into construction; the year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at the time a tree was cut.
Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, roots. This process is known as secondary growth; these cells go on to form thickened secondary cell walls, composed of cellulose and lignin. Where the differences between the four seasons are distinct, e.g. New Zealand, growth can occur in a discrete annual or seasonal pattern, leading to growth rings. If the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are to be indistinct or absent. If the bark of the tree has been removed in a particular area, the rings will be deformed as the plant overgrows the scar. If there are differences within a growth ring the part of a growth ring nearest the center of the tree, formed early in the growing season when growth is rapid, is composed of wider elements.
It is lighter in color than that near the outer portion of the ring, is known as earlywood or springwood. The outer portion formed in the season is known as the latewood or summerwood. However, there are major differences, depending on the kind of wood; as a tree grows, lower branches die, their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming a type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base, can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a circular "solid" piece of wood around which the grain of the rest of the wood "flows". Within a knot, the direction of the wood is up to 90 degrees different from the grain direction of the regular wood. In the tree a knot is either the base of a dormant bud.
A knot is conical in shape with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud. In grading lumber and structural timber, knots are classified according to their form, size and the firmness with which they are held in place; this firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow. Knots materially affect cracking and warping, ease in working, cleavability of timber, they are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or tension than when under load along the grain and/or compression; the extent to which knots affect the strength of a beam depends upon their position, size and condition. A knot on the upper side is compressed. If there is a season check