Paraboloid
In geometry, a paraboloid is a quadric surface that has one axis of symmetry and no center of symmetry. The term "paraboloid" is derived from parabola, which refers to a conic section that has the same property of symmetry. There are two types of paraboloid and hyperbolic, depending on the nature of the planar cross sections: a paraboloid is elliptic if the cross sections orthogonal to the axis of symmetry are ellipses. Cross sections of both types parallel to the axis of symmetry are parabolas. Equivalently, a paraboloid may be defined as a quadric surface, not a cylinder, has an implicit equation whose part of degree two may be factored over the complex numbers into two different linear factors; the paraboloid is hyperbolic. An elliptic paraboloid is shaped like an oval cup and has a maximum or minimum point when its axis is vertical. In a suitable coordinate system with three axes x, y, z, it can be represented by the equation z = x 2 a 2 + y 2 b 2. Where a and b are constants that dictate the level of curvature in the xz and yz planes respectively.
In this position, the elliptic paraboloid opens upward. A hyperbolic paraboloid is a doubly ruled surface shaped like a saddle. In a suitable coordinate system, a hyperbolic paraboloid can be represented by the equation z = y 2 b 2 − x 2 a 2. In this position, the hyperbolic paraboloid opens downward along the x-axis and upward along the y-axis. Any paraboloid can be considered as a translation surface in the sense of differential geometry, it can be generated by a moving parabola directed by a second parabola. With a = b an elliptic paraboloid is a paraboloid of revolution: a surface obtained by revolving a parabola around its axis, it is the shape of the parabolic reflectors used in mirrors, antenna dishes, the like. This shape is called a circular paraboloid. There is a point called the focus on the axis of a circular paraboloid such that, if the paraboloid is a mirror, light from a point source at the focus is reflected into a parallel beam, parallel to the axis of the paraboloid; this works the other way around: a parallel beam of light incident on the paraboloid parallel to its axis is concentrated at the focal point.
This applies for other waves, hence parabolic antennas. For a geometrical proof, click here; as plane sections of an elliptic paraboloid with equation z = x 2 a 2 + y 2 b 2 one gets the following cases: a parabola, if the plane is parallel to the z-axis, an ellipse or a point or empty, if the plane is not parallel to the z-axis. A point, if the plane is a tangent plane. Any elliptic paraboloid of revolution contains circles; this is true, but less obvious, in the general case. Remark: an elliptic paraboloid is projectively equivalent to a sphere; the hyperbolic paraboloid is a doubly ruled surface: it contains two families of mutually skew lines. The lines in each family are parallel to a common plane, but not to each other. Hence the hyperbolic paraboloid is a conoid; these properties characterize hyperbolic paraboloids and are used in one of the oldest definitions of hyperbolic paraboloids: a hyperbolic paraboloid is a surface that may be generated by a moving line, parallel to a fixed plane and crosses two fixed skew lines.
This property makes it simple to manufacture a hyperbolic paraboloid from a variety of materials and for a variety of purposes, from concrete roofs to snack foods. Pringles potato chips resemble a truncated hyperbolic paraboloid, their uniform shape allows them to be stacked in sturdy tubular containers, the strength of the hyperbolic paraboloid shape helps prevent them from breaking while stacked. Examples in architecture St. Mary's Cathedral, Tokyo Cathedral of Saint Mary of the Assumption, San Francisco, California Saddledome in Calgary, Canada London Velopark Dogra Hall, Indian Institute of Technology Delhi in New Delhi, India As plane sections of a hyperbolic paraboloid with equation z = x 2 a 2 − y 2 b 2 one gets the following cases: a parabola, if the plane is parallel to the z-axis with equation u x + v y + w = 0, a u ≠ ± b v, a line, if the plane is parallel to the z-axis with equation u x + v y + w = 0, a u = ± b v {\displaystyle ux+vy+w=0
University of Turin
The University of Turin is a university in the city of Turin in the Piedmont region of north-western Italy. It is one of the oldest universities in Europe, continues to play an important role in research and training, it is ranked among the top 5 Italian universities and it is ranked third for research activities in Italy, according to the latest data by ANVUR. The University of Turin was founded as a studium in 1404, under the initiative of Prince Ludovico di Savoia. From 1427 to 1436 the seat of the university was transferred to Savigliano, it was closed in 1536, reestablished by Duke Emmanuel Philibert thirty years later. It started to gain its modern shape following the model of the University of Bologna, although significant development did not occur until the reforms made by Victor Amadeus II, who created the Collegio delle Province for students not natives of Turin. With the reforms carried out by Victor Amadeus II, the University of Turin became a new reference model for many other universities.
During the 18th century, the University faced an enormous growth in faculty and endowment size, becoming a point of reference of the Italian Positivism. Notable scholars of this period include Carlo Forlanini and Arturo Graf. In the 20th century, the University of Turin was one of the centers of the Italian anti-fascism. After the post-war period, the increase in the number of students and the improvement of campus structure were imposing, although losing some of its importance until a new wave of investments carried out in the end of that century; the new impulse was performed in collaboration with other national and international research centers, as well as with local organizations and the Italian Minister of Public Instruction. By the end of the 1990s, the local campuses of Alessandria and Vercelli became autonomous units under the new University of Eastern Piedmont. In the beginning of the 15th century, instability in the Lombard region caused by the political and military crisis, coupled with the untimely death of Gian Galeazzo Visconti, induced the teaching staff of the Universities of Pavia and Piacenza to propose to Ludovico di Savoia-Acaia the creation of a new Studium generale.
Choice of the location fell on Turin for a number of reasons: first it was at the crossroads between the Alps and Lombardy. In autumn 1404, a bull issued by Benedict XIII, the Avignon Pope, marked the actual birth of a centre of higher learning, formally ratified in 1412 by the Emperor Sigmund's certification and subsequently, in 1413, by a bull issued by antipope John XXIII, the Pisan Pope, by another issued in 1419 by Martin V, Pope of Rome, by a series of papal privileges; the new institution, which only held courses in civil and canon law, was authorized to confer both the academic "licentia" and "doctoratus" titles that became a single "laurea" title. The Bishop, as Rector of Studies and conferred the title on the new doctors; the early decades were marked by discontinuity, due to epidemics and crises that plagued the region between the 1420s and the 1430s following the annexation of the Piedmont territories to the Duchy of Savoy and by difficult relations between the University and the local Public Administration.
After a series of interruptions in its activities, the university was moved to Chieri and in 1434, to Savigliano. In 1436, when the institution returned to Turin, Ludovico di Savoia, who succeeded Amedeo VIII, introduced a new order of studies whereby the Government gained greater control over the University; the ducal licenses of 6 October 1436 set up the three faculties of Theology and Medicine, Law, twenty-five lectureships or chairs. The growth and development of the role of Turin as the subalpine capital led to the consolidation of the University and a stability that lasted for a hundred years. From 1443 the University was housed in a modest building purchased and refurbished by the City for this purpose on the corner of via Doragrossa and via dello Studio directly behind the Town Hall, until the opening of the university premises in via Po, in 1720; the Study, closed at the beginning of 1536 with the French occupation, reopened in 1558 with lecturers at Mondovì. With Emmanuel Philibert and Charles Emmanuel I, the University enjoyed a season of great prosperity due to the presence of illustrious teachers and a sizeable and culturally motivated student body.
However, a lengthy period of decline set in around the second half of the 17th century because of plagues and continual wars: courses were irregular or temporarily suspended, the number of chairs was reduced, for those temporarily vacant, it was necessary to resort to private instruction. The opening of the new premises marked a major turning point in the history of the greatest Piedmontese educational institution; the inauguration building in via Po, close to Piazza Castello, the seats of power and other educational institutions of the City, coincided with the academic year 1720–1721, the first year of the reform of university studies passed by Victor Amadeus II in the context of a radical renewal at all levels of public administration and education. Victor Amadeus II was convinced that an efficient university controlled directly by the State was the only way to form a faithful and well-trained ruling class that could support him in the process of modernizing the Nation. While the War of Span
Le Corbusier
Charles-Édouard Jeanneret, known as Le Corbusier, was a Swiss-French architect, painter, urban planner and one of the pioneers of what is now called modern architecture. He was born in Switzerland and became a French citizen in 1930, his career spanned five decades, he designed buildings in Europe, Japan and North and South America. Dedicated to providing better living conditions for the residents of crowded cities, Le Corbusier was influential in urban planning, was a founding member of the Congrès International d'Architecture Moderne. Le Corbusier prepared the master plan for the city of Chandigarh in India, contributed specific designs for several buildings there. On 17 July 2016, seventeen projects by Le Corbusier in seven countries were inscribed in the list of UNESCO World Heritage Sites as The Architectural Work of Le Corbusier, an Outstanding Contribution to the Modern Movement. Charles-Édouard Jeanneret was born on 6 October 1887 in La Chaux-de-Fonds, a small city in the French-speaking Neuchâtel canton in north-western Switzerland, in the Jura mountains, just 5 kilometres across the border from France.
It was an industrial town, devoted to the manufacture of watches. His father was an artisan who enameled watches, while his mother gave piano lessons, his elder brother Albert was an amateur violinist. He attended a kindergarten. Like his contemporaries Frank Lloyd Wright and Mies van der Rohe, Le Corbusier did not have formal academic training as an architect, he was attracted to the visual arts and at the age of fifteen he entered the municipal art school in La-Chaux-de-Fonds which taught the applied arts connected with watchmaking. Three years he attended the higher course of decoration, founded by the painter Charles L'Eplattenier, who had studied in Budapest and Paris. Le Corbusier wrote that L'Eplattenier had made him "a man of the woods" and taught him painting from nature, his father took him into the mountains around the town. He wrote "we were on mountaintops, his architecture teacher in the Art School was the architect René Chapallaz, who had a large influence on Le Corbusier's earliest house designs.
However, he reported that it was the art teacher L'Eplattenier who made him choose architecture. "I had a horror of architecture and architects," he wrote. "... I was sixteen, I accepted the verdict and I obeyed. I moved into architecture." Le Corbusier began teaching himself by going to the library to read about architecture and philosophy, by visiting museums, by sketching buildings, by constructing them. In 1905, he and two other students, under the supervision of their teacher, René Chapallaz and built his first house, the Villa Fallet, for the engraver Louis Fallet, a friend of his teacher Charles L'Eplattenier. Located on the forested hillside near Chaux-de-fonds, it was a large chalet with a steep roof in the local alpine style and crafted colored geometric patterns on the façade. The success of this house led to his construction of two similar houses, the Villas Jacquemet and Stotzer, in the same area. In September 1907, he made his first trip outside of Switzerland. In Florence, he visited the Florence Charterhouse in Galluzzo, which made a lifelong impression on him.
"I would have liked to live in one of what they called their cells," he wrote later. "It was the solution for a unique kind of worker's housing, or rather for a terrestrial paradise." He traveled to Paris, during fourteen months between 1908 until 1910 he worked as a draftsman in the office of the architect Auguste Perret, the pioneer of the use of reinforced concrete in residential construction and the architect of the Art Deco landmark Théâtre des Champs-Élysées. Two years between October 1910 and March 1911, he traveled to Germany and worked four months in the office Peter Behrens, where Ludwig Mies van der Rohe and Walter Gropius were working and learning. In 1911, he traveled again for five months, he spoke of what he saw during this trip in many of his books, it was the subject of his last book, Le Voyage d'Orient. In 1912, he began his most ambitious project. Located on the forested hillside near La-Chaux-de-Fonds; the Jeanneret-Perret house was larger than the others, in a more innovative style.
The interior spaces were organized around the four pillars of the salon in the center, foretelling the open interiors he would create in his buildings. The project was more expensive to build. However, it led to a commission to build an more imposing villa in the nearby village of Le Locle for a wealthy watch manufacturer. Georges Favre-Jacot. Le Corbusier designed the new house in less than a month; the building was designed to fit its hillside site, interior plan was spacious and designed around a courtyard for maximum light, significant de
Multimedia
Multimedia is content that uses a combination of different content forms such as text, images, animations and interactive content. Multimedia contrasts with media that use only rudimentary computer displays such as text-only or traditional forms of printed or hand-produced material. Multimedia can be recorded and played, interacted with or accessed by information content processing devices, such as computerized and electronic devices, but can be part of a live performance. Multimedia devices are electronic media devices used to experience multimedia content. Multimedia is distinguished from mixed media in fine art. In the early years of multimedia the term "rich media" was synonymous with interactive multimedia, "hypermedia" was an application of multimedia; the term multimedia was coined by singer and artist Bob Goldstein to promote the July 1966 opening of his "LightWorks at L'Oursin" show at Southampton, Long Island. Goldstein was aware of an American artist named Dick Higgins, who had two years discussed a new approach to art-making he called "intermedia".
On August 10, 1966, Richard Albarino of Variety borrowed the terminology, reporting: "Brainchild of songscribe-comic Bob Goldstein, the'Lightworks' is the latest multi-media music-cum-visuals to debut as discothèque fare." Two years in 1968, the term "multimedia" was re-appropriated to describe the work of a political consultant, David Sawyer, the husband of Iris Sawyer—one of Goldstein's producers at L'Oursin. In the intervening forty years, the word has taken on different meanings. In the late 1970s, the term referred to presentations consisting of multi-projector slide shows timed to an audio track. However, by the 1990s'multimedia' took on its current meaning. In the 1993 first edition of Multimedia: Making It Work, Tay Vaughan declared "Multimedia is any combination of text, graphic art, sound and video, delivered by computer; when you allow the user – the viewer of the project – to control what and when these elements are delivered, it is interactive multimedia. When you provide a structure of linked elements through which the user can navigate, interactive multimedia becomes hypermedia."The German language society Gesellschaft für deutsche Sprache recognized the word's significance and ubiquitousness in the 1990s by awarding it the title of German'Word of the Year' in 1995.
The institute summed up its rationale by stating " has become a central word in the wonderful new media world". In common usage, multimedia refers to an electronically delivered combination of media including video, still images and text in such a way that can be accessed interactively. Much of the content on the web today falls within this definition; some computers which were marketed in the 1990s were called "multimedia" computers because they incorporated a CD-ROM drive, which allowed for the delivery of several hundred megabytes of video and audio data. That era saw a boost in the production of educational multimedia CD-ROMs; the term "video", if not used to describe motion photography, is ambiguous in multimedia terminology. Video is used to describe the file format, delivery format, or presentation format instead of "footage", used to distinguish motion photography from "animation" of rendered motion imagery. Multiple forms of information content are not considered modern forms of presentation such as audio or video.
Single forms of information content with single methods of information processing are called multimedia to distinguish static media from active media. In the fine arts, for example, Leda Luss Luyken's ModulArt brings two key elements of musical composition and film into the world of painting: variation of a theme and movement of and within a picture, making ModulArt an interactive multimedia form of art. Performing arts may be considered multimedia considering that performers and props are multiple forms of both content and media. Multimedia presentations may be viewed by person on stage, transmitted, or played locally with a media player. A broadcast may be a recorded multimedia presentation. Broadcasts and recordings can be digital electronic media technology. Digital online multimedia streamed. Streaming multimedia may be on-demand. Multimedia games and simulations may be used in a physical environment with special effects, with multiple users in an online network, or locally with an offline computer, game system, or simulator.
The various formats of technological or digital multimedia may be intended to enhance the users' experience, for example to make it easier and faster to convey information. Or in entertainment or art, to transcend everyday experience. Enhanced levels of interactivity are made possible by combining multiple forms of media content. Online multimedia is becoming object-oriented and data-driven, enabling applications with collaborative end-user innovation and personalization on multiple forms of content over time. Examples of these range from multiple forms of content on Web sites like photo galleries with both images and title user-updated, to simulations whose co-efficients, illustrations, animations or videos are modifiable, allowing the multimedia "experience" to be altered without reprogramming. In addition to seeing and hearing, haptic technology enables virtual objects to be felt. Emerging technology involving illusions of taste and smell may enhance the multimedia experience. Multimedia may be broadly divided into linear and non-linear categories: Linea
Musique concrète
Musique concrète is a type of music composition that utilizes recorded sounds as raw material, assembling them into a form of montage. It can feature sounds derived from recordings of musical instruments, the human voice, the natural environment as well as those created using synthesizers and computer-based digital signal processing. Compositions in this idiom are not restricted to the normal musical rules of melody, rhythm, so on, it exploits acousmatic listening, meaning sound identities can be intentionally obscured or appear unconnected to their source cause. Contrasted with "pure" elektronische Musik, the theoretical basis of musique concrète as a compositional practice was developed by Pierre Schaeffer, beginning in the early 1940s. From the late 1960s onward, in France, the term acousmatic music started to be used in reference to fixed media compositions that utilized both musique concrète based techniques and live sound spatialisation. In 1928 music critic André Cœuroy wrote in his book Panorama of Contemporary Music that "perhaps the time is not far off when a composer will be able to represent through recording, music composed for the gramophone".
In the same period the American composer Henry Cowell, in referring to the projects of Nikolai Lopatnikoff, believed that "there was a wide field open for the composition of music for phonographic discs." This sentiment was echoed further in 1930 by Igor Stravinsky, when he stated in the revue Kultur und Schallplatte that "there will be a greater interest in creating music in a way that will be peculiar to the gramophone record." The following year, 1931, Boris de Schloezer expressed the opinion that one could write for the gramophone or for the wireless just as one can for the piano or the violin. Shortly after, German art theorist Rudolf Arnheim discussed the effects of microphonic recording in an essay entitled "Radio", published in 1936. In it the idea of a creative role for the recording medium was introduced and Arnheim stated that: "The rediscovery of the musicality of sound in noise and in language, the reunification of music and language in order to obtain a unity of material:, one of the chief artistic tasks of radio".
In 1942 French composer and theoretician Pierre Schaeffer began his exploration of radiophony when he joined Jacques Copeau and his pupils in the foundation of the Studio d'Essai de la Radiodiffusion nationale. The studio functioned as a center for the Resistance movement in French radio, which in August 1944 was responsible for the first broadcasts in liberated Paris, it was here that Schaeffer began to experiment with creative radiophonic techniques using the sound technologies of the time. The development of Schaeffer's practice was informed by encounters with voice actors, microphone usage and radiophonic art played an important part in inspiring and consolidating Schaeffer's conception of sound-based composition. Another important influence on Schaeffer's practice was cinema, the techniques of recording and montage, which were associated with cinematographic practice, came to "serve as the substrate of musique concrète." Marc Battier notes that, prior to Schaeffer, Jean Epstein drew attention to the manner in which sound recording revealed what was hidden in the act of basic acoustic listening.
Epstein's reference to this "phenomenon of an epiphanic being", which appears through the transduction of sound, proved influential on Schaeffer's concept of reduced listening. Schaeffer would explicitly cite Jean Epstein with reference to his use of extra-musical sound material. Epstein had imagined that "through the transposition of natural sounds, it becomes possible to create chords and dissonances and symphonies of noise, which are a new and cinematographic music". Earlier than Schaeffer conducting his preliminary experiments into sound manipulation was the activity of Egyptian composer Halim El-Dabh; as a student in Cairo in the early to mid-1940s he began experimenting with "tape music" using a cumbersome wire recorder. He recorded the sounds of an ancient zaar ceremony and at the Middle East Radio studios processed the material using reverberation, voltage controls, re-recording; the resulting tape-based composition, entitled The Expression of Zaar, was presented in 1944 at an art gallery event in Cairo.
El-Dabh has described his initial activities as an attempt to unlock "the inner sound" of the recordings. While his early compositional work was not known outside of Egypt at the time, El-Dabh would gain recognition for his influential work at the Columbia-Princeton Electronic Music Center in the late 1950s. Following Schaeffer's work with Studio d'Essai at Radiodiffusion Nationale during the early 1940s he was credited with originating the theory and practice of musique concrète; the Studio d'Essai was renamed Club d'Essai de la Radiodiffusion-Télévision Française in 1946 and in the same year Schaeffer discussed, in writing, the question surrounding the transformation of time perceived through recording. The essay evidenced knowledge of sound manipulation techniques he would further exploit compositionally. In 1948 Schaeffer formally initiated "research in to noises" at the Club d'Essai and on 5 October 1948 the results of his ini
Philips
Koninklijke Philips N. V. is a Dutch multinational technology company headquartered in Amsterdam, one of the largest electronics companies in the world focused in the area of healthcare and lighting. It was founded in Eindhoven in 1891 by Gerard Philips and his father Frederik, with their first products being light bulbs, it was once one of the largest electronic conglomerates in the world and employs around 74,000 people across 100 countries. The company gained its royal honorary title in 1998 and dropped the "Electronics" in its name in 2013. Philips is organized into two main divisions: Philips Consumer Health and Well-being and Philips Professional Healthcare; the lighting division was spun off as a separate company, Signify N. V.. The company started making electric shavers in 1939 under the Philishave brand, post-war they developed the Compact Cassette format and co-developed the Compact Disc format with Sony, as well as numerous other technologies; as of 2012, Philips was the largest manufacturer of lighting in the world as measured by applicable revenues.
Philips has a primary listing on the Euronext Amsterdam stock exchange and is a component of the Euro Stoxx 50 stock market index. It has a secondary listing on the New York Stock Exchange. Acquisitions include that of Magnavox, they have had a sports club since 1913 called PSV Eindhoven. The Philips Company was founded by Gerard Philips and his father Frederik Philips. Frederik, a banker based in Zaltbommel, financed the purchase and setup of an empty factory building in Eindhoven, where the company started the production of carbon-filament lamps and other electro-technical products in 1892; this first factory is used as a museum. In 1895, after a difficult first few years and near bankruptcy, the Philipses brought in Anton, Gerard's younger brother by sixteen years. Though he had earned a degree in engineering, Anton started work as a sales representative. With Anton's arrival, the family business began to expand resulting in the founding of Philips Metaalgloeilampfabriek N. V. in Eindhoven in 1908, followed in 1912, by the foundation of Philips Gloeilampenfabrieken N.
V.. After Gerard and Anton Philips changed their family business by founding the Philips corporation, they laid the foundations for the electronics multinational. In the 1920s, the company started to manufacture other products, such as vacuum tubes. In 1939, they introduced the Philishave; the "Chapel" is a radio with built-in loudspeaker, designed during the early 1930s. On 11 March 1927, Philips went on the air with shortwave radio station PCJJ, joined in 1929 by sister station PHOHI. PHOHI broadcast in Dutch to the Dutch East Indies while PCJJ broadcast in English and German to the rest of the world; the international program on Sundays commenced in 1928, with host Eddie Startz hosting the Happy Station show, which became the world's longest-running shortwave program. Broadcasts from the Netherlands were interrupted by the German invasion in May 1940; the Germans commandeered the transmitters in Huizen to use for pro-Nazi broadcasts, some originating from Germany, others concerts from Dutch broadcasters under German control.
Philips Radio was absorbed shortly after liberation when its two shortwave stations were nationalised in 1947 and renamed Radio Netherlands Worldwide, the Dutch International Service. Some PCJ programs, such as Happy Station, continued on the new station. Philips was instrumental in the revival of the Stirling engine when, in the early 1930s, the management decided that offering a low-power portable generator would assist in expanding sales of its radios into parts of the world where mains electricity was unavailable and the supply of batteries uncertain. Engineers at the company's research lab carried out a systematic comparison of various power sources and determined that the forgotten Stirling engine would be most suitable, citing its quiet operation and ability to run on a variety of heat sources, they were aware that, unlike steam and internal combustion engines no serious development work had been carried out on the Stirling engine for many years and asserted that modern materials and know-how should enable great improvements.
Encouraged by their first experimental engine, which produced 16 W of shaft power from a bore and stroke of 30 mm × 25 mm, various development models were produced in a program which continued throughout World War II. By the late 1940s, the'Type 10' was ready to be handed over to Philips's subsidiary Johan de Witt in Dordrecht to be produced and incorporated into a generator set as planned; the result, rated at 180/200 W electrical output from a bore and stroke of 55 mm × 27 mm, was designated MP1002CA. Production of an initial batch of 250 began in 1951, but it became clear that they could not be made at a competitive price, besides with the advent of transistor radios with their much lower power requirements meant that the original rationale for the set was disappearing. 150 of these sets were produced. In parallel with the generator set, Philips developed experimental Stirling engines for a wide variety of applic
Reinforced concrete
Reinforced concrete is a composite material in which concrete's low tensile strength and ductility are counteracted by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is though not steel reinforcing bars and is embedded passively in the concrete before the concrete sets. Reinforcing schemes are designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of steel, polymers or alternate composite material in conjunction with rebar or not. Reinforced concrete may be permanently stressed, so as to improve the behaviour of the final structure under working loads. In the United States, the most common methods of doing this are known as pre-tensioning and post-tensioning. For a strong and durable construction the reinforcement needs to have the following properties at least: High relative strength High toleration of tensile strain Good bond to the concrete, irrespective of pH, similar factors Thermal compatibility, not causing unacceptable stresses in response to changing temperatures.
Durability in the concrete environment, irrespective of corrosion or sustained stress for example. François Coignet was the first to use iron-reinforced concrete as a technique for constructing building structures. In 1853, Coignet built the first iron reinforced concrete structure, a four-story house at 72 rue Charles Michels in the suburbs of Paris. Coignet's descriptions of reinforcing concrete suggests that he did not do it for means of adding strength to the concrete but for keeping walls in monolithic construction from overturning. In 1854, English builder William B. Wilkinson reinforced the concrete roof and floors in the two-storey house he was constructing, his positioning of the reinforcement demonstrated that, unlike his predecessors, he had knowledge of tensile stresses. Joseph Monier was a French gardener of the nineteenth century, a pioneer in the development of structural and reinforced concrete when dissatified with existing materials available for making durable flowerpots, he was granted a patent for reinforced flowerpots by means of mixing a wire mesh to a mortar shell.
In 1877, Monier was granted another patent for a more advanced technique of reinforcing concrete columns and girders with iron rods placed in a grid pattern. Though Monier undoubtedly knew reinforcing concrete would improve its inner cohesion, it is less known if he knew how much reinforcing improved concrete's tensile strength. Before 1877 the use of concrete construction, though dating back to the Roman Empire, having been reintroduced in the early 1800s, was not yet a proven scientific technology. American New Yorker Thaddeus Hyatt published a report titled An Account of Some Experiments with Portland-Cement-Concrete Combined with Iron as a Building Material, with Reference to Economy of Metal in Construction and for Security against Fire in the Making of Roofs and Walking Surfaces where he reported his experiments on the behavior of reinforced concrete, his work played a major role in the evolution of concrete construction as a proven and studied science. Without Hyatt's work, more dangerous trial and error methods would have been depended on for the advancement in the technology.
Ernest L. Ransome was an English-born engineer and early innovator of the reinforced concrete techniques in the end of the 19th century. With the knowledge of reinforced concrete developed during the previous 50 years, Ransome innovated nearly all styles and techniques of the previous known inventors of reinforced concrete. Ransome's key innovation was to twist the reinforcing steel bar improving bonding with the concrete. Gaining increasing fame from his concrete constructed buildings, Ransome was able to build two of the first reinforced concrete bridges in North America. One of the first concrete buildings constructed in the United States, was a private home, designed by William Ward in 1871; the home was designed to be fireproof for his wife. G. A. Wayss was a pioneer of the iron and steel concrete construction. In 1879, Wayss bought the German rights to Monier's patents and in 1884, he started the first commercial use for reinforced concrete in his firm Wayss & Freytag. Up until the 1890s, Wayss and his firm contributed to the advancement of Monier's system of reinforcing and established it as a well-developed scientific technology.
One of the first skyscrapers made with reinforced concrete was the 16-story Ingalls Building in Cincinnati, constructed in 1904. The first reinforced concrete building in Southern California was the Laughlin Annex in Downtown Los Angeles, constructed in 1905. In 1906, 16 building permits were issued for reinforced concrete buildings in the City of Los Angeles, including the Temple Auditorium and 8-story Hayward Hotel. On April 18, 1906 a magnitude 7.8 earthquake struck San Francisco. The strong ground shaking and subsequent fire killed thousands; the use of reinforced concrete after the earthquake was promoted within the U. S. construction industry due to its non-combustibility and perceived superior seismic performance relative to masonry. In 1906, a partial collapse of the Bixby Hotel in Long Beach killed 10 workers during construction when shoring was removed prematurely; this event spurred a scrutiny of concrete erection practices and building inspections. The structure was constructed of reinforced concrete frames with hollow clay tile ribbed flooring and hollow clay
