1.
Pantograph (transport)
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A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead catenary wire. It is a type of current collector. Typically, a wire is used, with the return current running through the track. The term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting, the pantograph was invented in 1879 by Walter Reichel, chief engineer at Siemens & Halske in Germany. A flat slide-pantograph was invented in 1895 at the Baltimore and Ohio Railroad The familiar diamond-shaped roller pantograph was invented by John Q. Brown of the Key System shops for their commuter trains ran between San Francisco and the East Bay section of the San Francisco Bay Area in California. They appear in photographs of the first day of service,26 October 1903, for many decades thereafter, the same diamond shape was used by electric-rail systems around the world and remains in use by some today. The most common type of today is the so-called half-pantograph. Louis Faiveley invented this type of pantograph in 1955, the half-pantograph can be seen in use on everything from very fast trains to low-speed urban tram systems. The electric transmission system for electric rail systems consists of an upper. The pantograph is spring-loaded and pushes a contact shoe up against the underside of the wire to draw the current needed to run the train. The steel rails of the act as the electrical return. As the train moves, the shoe slides along the wire and can set up standing waves in the wires which break the contact. This means that on some systems adjacent pantographs are not permitted, pantographs are the successor technology to trolley poles, which were widely used on early streetcar systems. However, many of these networks, including Torontos, are undergoing upgrades to accommodate pantograph operation, as a precaution against loss of pressure in the second case, the arm is held in the down position by a catch. For high-voltage systems, the air supply is used to blow out the electric arc when roof-mounted circuit breakers are used. Pantographs may have either a single or a double arm, double-arm pantographs are usually heavier, requiring more power to raise and lower, but may also be more fault-tolerant. On railways of the former USSR, the most widely used pantographs are those with a double arm, some streetcars use double-arm pantographs, among them the Russian KTM-5, KTM-8, LVS-86 and many other Russian-made trams, as well as some Euro-PCC trams in Belgium
2.
Linkage (mechanical)
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A mechanical linkage is an assembly of bodies connected to manage forces and movement. The movement of a body, or link, is studied using geometry so the link is considered to be rigid, the connections between links are modeled as providing ideal movement, pure rotation or sliding for example, and are called joints. A linkage modeled as a network of links and ideal joints is called a kinematic chain. Linkages may be constructed from open chains, closed chains, or a combination of open, each link in a chain is connected by a joint to one or more other links. Thus, a chain can be modeled as a graph in which the links are paths and the joints are vertices. The movement of a joint is generally associated with a subgroup of the group of Euclidean displacements. The number of parameters in the subgroup is called the degrees of freedom of the joint, mechanical linkages are usually designed to transform a given input force and movement into a desired output force and movement. The ratio of the force to the input force is known as the mechanical advantage of the linkage. The speed ratio and mechanical advantage are defined so they yield the number in an ideal linkage. A kinematic chain, in which one link is fixed or stationary, is called a mechanism, perhaps the simplest linkage is the lever, which is a link that pivots around a fulcrum attached to ground, or a fixed point. As a force rotates the lever, points far from the fulcrum have a greater velocity than points near the fulcrum. Because power into the lever equals the power out, a force applied at a point far from the fulcrum equals a larger force applied at a point near the fulcrum. The amount the force is amplified is called mechanical advantage and this is the law of the lever. Two levers connected by a rod so that a force applied to one is transmitted to the second is known as a four-bar linkage, the levers are called cranks, and the fulcrums are called pivots. The connecting rod is also called the coupler, the fourth bar in this assembly is the ground, or frame, on which the cranks are mounted. Linkages are important components of machines and tools, examples range from the four-bar linkage used to amplify force in a bolt cutter or to provide independent suspension in an automobile, to complex linkage systems in robotic arms and walking machines. The internal combustion engine uses a slider-crank four-bar linkage formed from its piston, connecting rod, relatively simple linkages are often used to perform complicated tasks. Interesting examples of linkages include the windshield wiper, the bicycle suspension, in these examples the components in the linkage move in parallel planes and are called planar linkages
3.
Parallelogram
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In Euclidean geometry, a parallelogram is a simple quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length, by comparison, a quadrilateral with just one pair of parallel sides is a trapezoid in American English or a trapezium in British English. The three-dimensional counterpart of a parallelogram is a parallelepiped, rhomboid – A quadrilateral whose opposite sides are parallel and adjacent sides are unequal, and whose angles are not right angles Rectangle – A parallelogram with four angles of equal size. Rhombus – A parallelogram with four sides of equal length, square – A parallelogram with four sides of equal length and angles of equal size. A simple quadrilateral is a if and only if any one of the following statements is true. Two pairs of opposite angles are equal in measure, one pair of opposite sides are parallel and equal in length. Each diagonal divides the quadrilateral into two congruent triangles, the sum of the squares of the sides equals the sum of the squares of the diagonals. It has rotational symmetry of order 2, the sum of the distances from any interior point to the sides is independent of the location of the point. Thus all parallelograms have all the properties listed above, and conversely, if just one of statements is true in a simple quadrilateral. Opposite sides of a parallelogram are parallel and so will never intersect, the area of a parallelogram is twice the area of a triangle created by one of its diagonals. The area of a parallelogram is also equal to the magnitude of the cross product of two adjacent sides. Any line through the midpoint of a parallelogram bisects the area, any non-degenerate affine transformation takes a parallelogram to another parallelogram. A parallelogram has rotational symmetry of order 2, if it also has exactly two lines of reflectional symmetry then it must be a rhombus or an oblong. If it has four lines of symmetry, it is a square. The perimeter of a parallelogram is 2 where a and b are the lengths of adjacent sides, unlike any other convex polygon, a parallelogram cannot be inscribed in any triangle with less than twice its area. The centers of four squares all constructed either internally or externally on the sides of a parallelogram are the vertices of a square. If two lines parallel to sides of a parallelogram are constructed concurrent to a diagonal, then the parallelograms formed on opposite sides of that diagonal are equal in area, the diagonals of a parallelogram divide it into four triangles of equal area. All of the formulas for general convex quadrilaterals apply to parallelograms
4.
Accordion
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Accordions are a family of box-shaped musical instruments of the bellows-driven free-reed aerophone type, colloquially referred to as a squeezebox. A person who plays the accordion is called an accordionist, the concertina and bandoneón are related, the harmonium and American reed organ are in the same family. The instrument is played by compressing or expanding the bellows while pressing buttons or keys, causing pallets to open and these vibrate to produce sound inside the body. Valves on opposing reeds of each note are used to make the instruments reeds sound louder without air leaking from each reed block. The performer normally plays the melody on buttons or keys on the manual. The accordion is widely spread across the world, nevertheless, in Europe and North America, some popular music acts also make use of the instrument. Additionally, the accordion is used in cajun, zydeco, jazz music. The piano accordion is the official city instrument of San Francisco, the oldest name for this group of instruments is harmonika, from the Greek harmonikos, meaning harmonic, musical. Today, native versions of the accordion are more common. These names refer to the type of accordion patented by Cyrill Demian, accordions have many configurations and types. Similar to a bow, the production of sound in an accordion is in direct proportion to the motion of the player. The bellows is located between the right- and left-hand manuals, and is made from pleated layers of cloth and cardboard, with added leather and metal. It is used to pressure and vacuum, driving air across the internal reeds and producing sound by their vibration. These boxes house reed chambers for the right- and left-hand manuals, each side has grilles in order to facilitate the transmission of air in and out of the instrument, and to allow the sound to better project. The grille for the manual is usually larger and is often shaped for decorative purposes. The right-hand manual is used for playing the melody and the left-hand manual for playing the accompaniment. The manual mechanism of the instrument either enables the air flow, or disables it, the different types have varying components. All instruments have reed ranks of some format, the most typical accordion is the piano accordion, which is used for many musical genres
5.
Rhomboidal
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Traditionally, in two-dimensional geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are non-right angled. A parallelogram with sides of length is a rhombus but not a rhomboid. A parallelogram with right angled corners is a rectangle but not a rhomboid, the term rhomboid is now more often used for a parallelepiped, a solid figure with six faces in which each face is a parallelogram and pairs of opposite faces lie in parallel planes. Some crystals are formed in three-dimensional rhomboids and this solid is also sometimes called a rhombic prism. The term occurs frequently in science terminology referring to both its two- and three-dimensional meaning, and let quadrilaterals other than these be called trapezia. Heath suggests that rhomboid was a term already in use. The rhomboid has no line of symmetry, but it has symmetry of order 2. In biology, rhomboid may describe a geometric rhomboid or a bilaterally-symmetrical kite-shaped or diamond-shaped outline, in a type of arthritis called pseudogout, crystals of calcium pyrophosphate dihydrate accumulate in the joint, causing inflammation. Aspiration of the joint fluid reveals rhomboid-shaped crystals under a microscope
6.
Aerial work platform
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A cherry picker is a type of aerial work platform that consists of a platform or bucket at the end of a hydraulic lifting system. It may be mounted on a truck or van or on a self-propelled platform. It is often mounted on the back of a vehicle such as a truck, it can also be mounted on a flat bed or paneled van. The bucket is designed for a person to stand in and work from, often a duplicate set of controls that are used to manipulate the position of the bucket will be available to the person in the bucket, allowing the operator to position himself. The lifting arms of some cherry pickers are capable of telescoping to adjust the reach of the device, articulated boom lifts are more appropriate than stick booms when operating in tight spaces or when clearing nearby obstacles is necessary. Cherry pickers can either be electrically powered using batteries or powered with a diesel engine, there are advantages and disadvantages associated with both types of power. Cherry pickers were originally designed for use in orchards where they are used frequently. It lets the fruit picker pick fruit high in a tree with relative ease, similar devices, also known as cherry pickers, are used to service telephone, cable television, and electrical equipment on utility poles. Christmas light displays and banners can also be affixed with a cherry picker, some fire trucks have a cherry picker, known as a snorkel, instead of a ladder. Some window cleaners also use them, Cherry pickers are also used in mining, construction, exterior painting, and sometimes by arborists to work safely in otherwise unclimbable trees. Cherry pickers were used for the Mayor of Londons Hatwalk in July 2012. Cherry pickers were used to put hats onto the heads of some of the citys most iconic statues, Cherry pickers are also used to rescue people from roller coasters if the cars are stuck. In the film and television industry, cherry pickers are known as condors and are used to suspend large lights above sets when not on a soundstage. Some artists use cherry pickers on stage for effects, most notably Michael Jackson, Justin Bieber, Jackson would use one on his tours performing Beat It and Earth Song from above the crowd. Bieber used one on a set which featured Be Alright. West used one on his song Dark Fantasy which was usually the opening of his concerts, david Bowie claimed to be the first pop star who used a cherry picker on stage during his theatrical Diamond Dogs Tour which started on 14 June 1974. Ceramic boom lifts can be utilised for specialised work in confined spaces, however, top 5 Uses for a Cherry Picker Media related to Cherry pickers at Wikimedia Commons
7.
Scissors mechanism
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A scissors mechanism uses linked, folding supports in a criss-cross X pattern, known as a pantograph. Extension is achieved by applying pressure to the outside of a set of supports located at one end of the mechanism and this can be achieved through hydraulic, pneumatic, mechanical or simply muscular means. It may require no power to return to its original position and this mechanism is used in devices such as lift tables and scissor lifts
8.
Christoph Scheiner
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Christoph Scheiner SJ was a Jesuit priest, physicist and astronomer in Ingolstadt. Scheiner was born in Markt Wald near Mindelheim in Swabia, earlier markgravate Burgau and he attended the Jesuit St. Salvator Grammar School in Augsburg from May 1591 until October 24,1595. He graduated as a rhetor and entered the Jesuit Order in Landsberg am Lech on October 26,1595, at the local seminary, he served his biennial novitiate under the tutelage of Novice Master Father Rupert Reindl SJ. From 1597 to 1598, he finished his studies of rhetoric in Augsburg. He took his first vows before Father Melchior Stör, SJ and he spent the years 1598–1601 in Ingolstadt studying philosophy. In 1603, Scheiner invented the pantograph, an instrument which could duplicate plans, from 1603 to 1605 he taught humanities, his years as a Latin teacher at the Jesuit grammar school in Dillingen earned him the title of Magister Artium. From the autumn of 1605 until 1609, Scheiner studied theology in Ingolstadt, due to his invention of the pantograph, he had already gained celebrity status. Duke William V of Bavaria even invited him to Munich to demonstrate the instrument, on March 14,1609, he entered Holy Orders as a Deacon. He was ordained by suffragan bishop Marcus Lyresius, Scheiner finished his studies on June 30,1609 with his first work, Theses Theologicae and with a disputation. On April 18,1609, he received his orders from suffragan bishop Lyresius in Eichstätt. In the years between 1610 and 1616/1617, Scheiner worked as a successor to Father Johannes Lantz S. J. in Ingolstadt, teaching mathematics and he lectured on sun dials, practical geometry, astronomy, optics, and the telescope. In 1611, Scheiner observed sunspots, in 1612 he published the Apelles letters in Augsburg, mark Welser had the first three Apelles letters printed in Augsburg on January 5,1612. They provided one of reasons for the subsequent unpleasant argument between Scheiner and Galileo Galilei. Scheiner took his vows of poverty, chastity, obedience. In the very same year Scheiner made known his wish to go to China as a missionary, Father General Mutio Vitelleschi sent him a letter, however, telling Scheiner he had better stay in Europe and persevere with his mathematical studies. In the winter of 1617/1618, Scheiner returned to Innsbruck, Austria at the behest of Archduke Maximilian III, after November 1614, Archduke Maximilian III summoned Scheiner to Innsbruck several times to discuss astronomical and mathematical questions. The Archduke had received an astronomical telescope with two convex lenses which showed objects upside down and the way round. Scheiner added a third lens, thus manufacturing a terrestrial telescope which allowed Maximilian to see the beautiful stretches of his country while standing upright, a portable camera obscura was developed by Scheiner in Innsbruck
9.
William Wallace (mathematician)
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Prof William Wallace FRSE MInstCE FRAS LLD was a Scottish mathematician and astronomer who invented the eidograph. Wallace was born at Dysart in Fife, where he received his school education and he was further assisted in his studies by John Robison and John Playfair, to whom his abilities had become known. After various changes of situation, dictated mainly by a desire to gain time for study, he became assistant teacher of mathematics in the academy of Perth in 1794. This post he exchanged in 1803 for a mastership in the Royal Military College at Great Marlow, in which post he continued after it moved to Sandhurst. In 1819 he was chosen to succeed John Leslie in the chair of mathematics at Edinburgh, Wallace developed a reputation for being an excellent teacher. Among his students was Mary Somerville, in 1838 he retired from the university due to ill health. He died in Edinburgh and was buried in Greyfriars Kirkyard, the grave lies on the north-facing wall in the centre of the northern section. In his earlier years Wallace was a contributor to Leybournes Mathematical Repository. He was also the author of the principal mathematical articles in the Edinburgh Encyclopædia and he also contributed many important papers to the Transactions of the Royal Society of Edinburgh. He mainly worked in the field of geometry and in 1799 became the first to publish the concept of the Simson line, in 1807 he proved a result about polygons with an equal area, that later became known as the Bolyai–Gerwien theorem. Wallace also worked in astronomy and invented the eidograph, a device for scaling drawings. A Geometrical Treatise on the Conic Sections with an Appendix Containing Formulae for their Quadrature, Geometrical Theorems and Analytical Formulae with their application to the Solution of Certain Geodetical Problems and an Appendix. Wallace was married to Janet Kerr and his daughter, Margaret Wallace, married the mathematician Thomas Galloway. His sons included the Rev Alexander Wallace and Archibald C, attribution This article incorporates text from a publication now in the public domain, Chisholm, Hugh, ed. Wallace, William. OConnor, John J. Robertson, Edmund F. William Wallace, MacTutor History of Mathematics archive, short biographical note on William Wallace in the Gazetteer for Scotland
10.
Technical drawing
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Technical drawing, drafting or drawing, is the act and discipline of composing drawings that visually communicate how something functions or is constructed. Technical drawing is essential for communicating ideas in industry and engineering, to make the drawings easier to understand, people use familiar symbols, perspectives, units of measurement, notation systems, visual styles, and page layout. Together, such conventions constitute a language and help to ensure that the drawing is unambiguous. Many of the symbols and principles of drawing are codified in an international standard called ISO128. The need for communication in the preparation of a functional document distinguishes technical drawing from the expressive drawing of the visual arts. Artistic drawings are subjectively interpreted, their meanings are multiply determined, Technical drawings are understood to have one intended meaning. A drafter, draftsperson, or draughtsman is a person who makes a drawing, a professional drafter who makes technical drawings is sometimes called a drafting technician. Professional drafting is a desirable and necessary function in the design and manufacture of mechanical components. Professional draftspersons bridge the gap between engineers and manufacturers and contribute experience and technical expertise to the design process, the basic drafting procedure is to place a piece of paper on a smooth surface with right-angle corners and straight sides—typically a drawing board. A sliding straightedge known as a T-square is then placed on one of the sides, allowing it to be slid across the side of the table, parallel lines can be drawn simply by moving the T-square and running a pencil or technical pen along the T-squares edge. The T-square is used to other devices such as set squares or triangles. Modern drafting tables come equipped with a machine that is supported on both sides of the table to slide over a large piece of paper. Because it is secured on both sides, lines drawn along the edge are guaranteed to be parallel, in addition, the drafter uses several technical drawing tools to draw curves and circles. Primary among these are the compasses, used for drawing simple arcs and circles, a spline is a rubber coated articulated metal that can be manually bent to most curves. Drafting templates assist the drafter with creating recurring objects in a drawing without having to reproduce the object from scratch every time. Templates are sold commercially by a number of vendors, usually customized to a specific task and this basic drafting system requires an accurate table and constant attention to the positioning of the tools. A common error is to allow the triangles to push the top of the T-square down slightly, thereby throwing off all angles. Even tasks as simple as drawing two angled lines meeting at a point require a number of moves of the T-square and triangles and these machines often included the ability to change the angle, thereby removing the need for the triangles as well
11.
Computer-aided manufacturing
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Computer-aided manufacturing is the use of software to control machine tools and related ones in the manufacturing of workpieces. CAM is now a used in schools and lower educational purposes. CAM is used in schools alongside computer-aided design to create objects. Historically, CAM software was seen to have shortcomings that necessitated an overly high level of involvement by skilled CNC machinists. Fallows created the first CAD software but this had severe shortcomings and was taken back into the developing stage. CAM software would output code for the least capable machine, as machine tool control added on to the standard G-code set for increased flexibility. In some cases, such as set up CAM software or specific tools. None of these issues were so insurmountable that an engineer or skilled machine operator could not overcome for prototyping or small production runs. In high production or high precision shops, a different set of problems were encountered where an experienced CNC machinist must both hand-code programs and run CAM software, integration of CAD with other components of CAD/CAM/CAE Product lifecycle management environment requires an effective CAD data exchange. CAM packages could not, and still cannot, reason as a machinist can and they could not optimize toolpaths to the extent required of mass production. Users would select the type of tool, machining process and paths to be used, while an engineer may have a working knowledge of G-code programming, small optimization and wear issues compound over time. Mass-produced items that require machining are often created through casting or some other non-machine method. This enables hand-written, short, and highly optimized G-code that could not be produced in a CAM package. At least in the United States, there is a shortage of young, skilled machinists entering the workforce able to perform at the extremes of manufacturing, high precision and mass production. User confidence is built on 3D visualization through a closer integration with the 3D CAD environment. Manufacturing complexity The manufacturing environment is increasingly complex, the need for CAM and PLM tools by buMs are NC programmer or machinist is similar to the need for computer assistance by the pilot of modern aircraft systems. The modern machinery cannot be used without this assistance. Todays CAM systems support the range of machine tools including, turning,5 axis machining
12.
CNC router
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CNC router is a computer-controlled cutting machine related to the hand held router used for cutting various hard materials, such as wood, composites, aluminium, steel, plastics, and foams. CNC stands for computer numerical control, CNC routers can perform the tasks of many carpentry shop machines such as the panel saw, the spindle moulder, and the boring machine. They can also cut mortises and tenons, a CNC router is very similar in concept to a CNC milling machine. Instead of routing by hand, tool paths are controlled via computer numerical control, the CNC router is one of many kinds of tools that have CNC variants. A CNC router typically produces consistent and high-quality work and improves factory productivity, unlike a jig router, the CNC router can produce a one-off as effectively as repeated identical production. Automation and precision are the key benefits of cnc router tables, a CNC router can reduce waste, frequency of errors, and the time the finished product takes to get to market. In addition, the CNC router helps in the thermoforming of plastics by automating the trimming process, CNC routers can help ensure part repeatability and sufficient factory output. CAM software makes the CAD drawing/design into a code called g-code. This code the CNC machine can understand, in short, CNC technology is not very complicated. It is a controlled by a computer. It only becomes more sophisticated when considering how the controls the tool. The illustration shows what a bare bones CNC machine might look like without its controller, CNC routers come in many configurations, from small home-style D. I. Y. Desktop like k2 cnc, to large industrialCNC routers used in shops, cabinet making, aerospace. Originally CNC routers added computer control to consumer router power tools, in addition, CNC routers may have vacuum pumps, with grid table tops or t slot hold down fixtures to hold the parts in place for cutting. CNC routers are generally available in 3-axis and 5-axis CNC formats, many Manufacturers offer A and B Axis for full 5 Axis capabilities and rotary 4th axis. The CNC router is controlled by a computer, coordinates are uploaded into the machine controller from a separate CAD program. CNC router owners often have two software applications—one program to make designs and another to translate those designs into a G-Code program of instructions for the machine, a CNC wood router is a CNC Router tool that creates objects from wood. CNC stands for computer numerical control, the CNC works on the Cartesian coordinate system for 3D motion control. Milling is the process of using rotary cutters to remove material from a workpiece advancing in a direction at an angle with the axis of the tool
13.
3D scanner
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A 3D scanner is a device that analyses a real-world object or environment to collect data on its shape and possibly its appearance. The collected data can then be used to construct digital three-dimensional models, many different technologies can be used to build these 3D-scanning devices, each technology comes with its own limitations, advantages and costs. Many limitations in the kind of objects that can be digitised are still present, for example, optical technologies encounter many difficulties with shiny, for example, industrial computed tomography scanning can be used to construct digital 3D models, applying non-destructive testing. Collected 3D data is useful for a variety of applications. These devices are used extensively by the entertainment industry in the production of movies, the purpose of a 3D scanner is usually to create a point cloud of geometric samples on the surface of the subject. These points can then be used to extrapolate the shape of the subject, if colour information is collected at each point, then the colours on the surface of the subject can also be determined. 3D scanners share several traits with cameras, like most cameras, they have a cone-like field of view, and like cameras, they can only collect information about surfaces that are not obscured. While a camera collects colour information about surfaces within its field of view, the picture produced by a 3D scanner describes the distance to a surface at each point in the picture. This allows the three dimensional position of point in the picture to be identified. For most situations, a single scan will not produce a model of the subject. Multiple scans, even hundreds, from different directions are usually required to obtain information about all sides of the subject. These scans have to be brought into a reference system, a process that is usually called alignment or registration. This whole process, going from the range map to the whole model, is usually known as the 3D scanning pipeline. There are a variety of technologies for digitally acquiring the shape of a 3D object, a well established classification divides them into two types, contact and non-contact. Non-contact solutions can be divided into two main categories, active and passive. There are a variety of technologies that fall under each of these categories, where the object to be scanned is not flat or can not rest stably on a flat surface, it is supported and held firmly in place by a fixture. The scanner mechanism may have three different forms, A carriage system with rigid arms held tightly in perpendicular relationship and each axis gliding along a track, such systems work best with flat profile shapes or simple convex curved surfaces. An articulated arm with rigid bones and high precision angular sensors, the location of the end of the arm involves complex math calculating the wrist rotation angle and hinge angle of each joint
14.
Scale model
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This enables it to demonstrate some behavior or property of the original object without examining the original object itself. The most familiar scale models represent the appearance of an object in miniature. Scale models are used in fields including engineering, architecture, film making, military command, salesmanship. While each field may use a model for a different purpose, all scale models are based on the same principles. The detail requirements vary depending on the needs of the modeler, in general a scale model must be designed and built primarily considering similitude theory. However, other requirements concerning practical issues must also be considered, similitude is the theory and art of predicting prototype performance from scale model observations. The main requirement of similitude is all dimensionless quantities must be equal for both the model and the prototype under the conditions the modeler desires to make observations. Dimensionless quantities are generally referred to as Pi terms, or π terms, in many fields the π terms are well established. For example, in dynamics, a well known dimensionless number called the Reynolds number comes up frequently in scale model tests with fluid in motion relative to a stationary surface. An example of the Reynolds number and its use in similitude theory satisfaction can be observed in the scale model testing of fluid flow in a horizontal pipe, one method to determine the dimensionless quantities of concern for a given problem is to use dimensional analysis. Practical concerns include the cost to construct the model, available test facilities to condition and observe the model, the availability of certain materials, and even who will build it. Practical requirements are very diverse depending on the purpose of the scale model. As an example, perhaps an aerospace company needs to test a new wing shape, however, if a facility such as this one cant be used, perhaps due to cost constraints, the similitude requirements must be relaxed or the test redesigned to accommodate the limitation. In this case, concessions must be made for reasons to the similitude requirements. An example of this from fluid dynamics is flow of a liquid in a horizontal pipe, possible π terms to consider in this situation are Reynolds number, Weber number, Froude number, and Mach number. For this flow configuration, however, no tension is involved. Also, compression of the fluid is not applicable, so the Mach number can be disregarded, finally, gravity is not responsible for the flow, so the Froude number can also be disregarded. This leaves the modeler with only the Reynolds number to worry about in terms of equating its values for the scale model, in general, scale models can be classified into three classes depending on the degree of similitude satisfaction they exhibit
15.
James Watt
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While working as an instrument maker at the University of Glasgow, Watt became interested in the technology of steam engines. He realised that contemporary engine designs wasted a great deal of energy by repeatedly cooling and reheating the cylinder, Watt introduced a design enhancement, the separate condenser, which avoided this waste of energy and radically improved the power, efficiency, and cost-effectiveness of steam engines. Eventually he adapted his engine to produce rotary motion, greatly broadening its use beyond pumping water, Watt attempted to commercialise his invention, but experienced great financial difficulties until he entered a partnership with Matthew Boulton in 1775. The new firm of Boulton and Watt was eventually highly successful, in his retirement, Watt continued to develop new inventions though none was as significant as his steam engine work. He developed the concept of horsepower, and the SI unit of power, James Watt was born on 19 January 1736 in Greenock, Renfrewshire, a seaport on the Firth of Clyde. His father was a shipwright, ship owner and contractor, and served as the towns chief baillie, while his mother, Agnes Muirhead, both were Presbyterians and strong Covenanters. Watts grandfather, Thomas Watt, was a teacher and baillie to the Baron of Cartsburn. Despite being raised by parents, he later on became a deist. Watt did not attend regularly, initially he was mostly schooled at home by his mother but later he attended Greenock Grammar School. He exhibited great manual dexterity, engineering skills and an aptitude for mathematics, while Latin, when he was eighteen, his mother died and his fathers health began to fail. Watt travelled to London to study instrument-making for a year, then returned to Scotland and he made and repaired brass reflecting quadrants, parallel rulers, scales, parts for telescopes, and barometers, among other things. Because he had not served at least seven years as an apprentice, Watt was saved from this impasse by the arrival from Jamaica of astronomical instruments bequeathed by Alexander Macfarlane to the University of Glasgow, instruments that required expert attention. Watt restored them to working order and was remunerated and these instruments were eventually installed in the Macfarlane Observatory. Subsequently three professors offered him the opportunity to set up a workshop within the university. It was initiated in 1757 and two of the professors, the physicist and chemist Joseph Black as well as the famed Adam Smith, at first he worked on maintaining and repairing scientific instruments used in the university, helping with demonstrations, and expanding the production of quadrants. In 1759 he formed a partnership with John Craig, an architect and businessman, to manufacture and sell a line of products including musical instruments and this partnership lasted for the next six years, and employed up to sixteen workers. One employee, Alex Gardner, eventually took over the business, in 1764, Watt married his cousin Margaret Miller, with whom he had five children, two of whom lived to adulthood, James Jr. and Margaret. His wife died in childbirth in 1772, in 1777 he was married again, to Ann MacGregor, daughter of a Glasgow dye-maker, with whom he had two children, Gregory, who became a geologist and mineralogist, and Janet
16.
Relief
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Relief is a sculptural technique where the sculpted elements remain attached to a solid background of the same material. The term relief is from the Latin verb relevo, to raise, to create a sculpture in relief is to give the impression that the sculpted material has been raised above the background plane. What is actually performed when a relief is cut in from a surface of stone or wood is a lowering of the field. The technique involves considerable chiselling away of the background, which is a time-consuming exercise. In other materials such as metal, clay, plaster stucco, ceramics or papier-mâché the form can be just added to or raised up from the background, and monumental bronze reliefs are made by casting. There are different degrees of relief depending on the degree of projection of the form from the field. There is also sunk relief, which was restricted to Ancient Egypt. However the distinction between high relief and low relief is the clearest and most important, and these two are generally the only used to discuss most work. Hyphens may or may not be used in all these terms, works in the technique are described as in relief, and, especially in monumental sculpture, the work itself is a relief. Reliefs are common throughout the world on the walls of buildings and a variety of settings. Relief is more suitable for depicting complicated subjects with figures and very active poses, such as battles. Most ancient architectural reliefs were painted, which helped to define forms in low relief. Rock reliefs are carved into solid rock in the open air. This type is found in cultures, in particular those of the Ancient Near East and Buddhist countries. A stele is a standing stone, many of these carry reliefs. The distinction between high and low relief is somewhat subjective, and the two are often combined in a single work. In particular, most later high reliefs contain sections in low relief, a low relief or bas-relief is a projecting image with a shallow overall depth, for example used on coins, on which all images are in low relief. Other versions distort depth much less and it is a technique which requires less work, and is therefore cheaper to produce, as less of the background needs to be removed in a carving, or less modelling is required
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Coin
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A coin is a small, flat, round piece of metal or plastic used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in quantities at a mint in order to facilitate trade. They are most often issued by a government, Coins are usually metal or alloy, or sometimes made of synthetic materials. Coins made of metal are stored in large quantities as bullion coins. Other coins are used as money in transactions, circulating alongside banknotes. Usually the highest value coin in circulation is less than the lowest-value note. In the last hundred years, the value of circulation coins has occasionally been lower than the value of the metal they contain. Exceptions to the rule of face value being higher than content value also occur for some bullion coins made of copper, silver, or gold, while the Eagle, Maple Leaf, and Sovereign coins have nominal face values, the Krugerrand does not. The first coins were developed independently in Iron Age Anatolia and Archaic Greece, India, Coins spread rapidly in the 6th and 5th centuries BCE, throughout Greece and Persia, and further to the Balkans. Standardized Roman currency was used throughout the Roman Empire, important Roman gold and silver coins were continued into the Middle Ages. Fiat money first arose in medieval China, with the paper money. Early paper money was introduced in Europe in the later Middle Ages, the penny was minted as a silver coin until the 17th century. The first circulating United States coins were cents, produced in 1793, Coins were an evolution of currency systems of the Late Bronze Age, where standard-sized ingots, and tokens such as knife money, were used to store and transfer value. In the late Chinese Bronze Age, standardized cast tokens were made and these were replicas in bronze of earlier Chinese currency, cowrie shells, so they were named Bronze Shell. According to Aristotle and Pollux, the first issuer of coins was Hermodike of Kyme The earliest coins are associated with Iron Age Anatolia. Early electrum coins were not standardized in weight, and in their earliest stage may have been ritual objects, such as badges or medals, issued by priests. The first Lydian coins were made of electrum, a naturally occurring alloy of silver, most of the early Lydian coins include no writing, only an image of a symbolic animal. Anatolian Artemis was the Πὀτνια Θηρῶν, whose symbol was the stag, a small percentage of early Lydian/Greek coins have a legend
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Phonograph
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The phonograph is a device invented in 1877 for the mechanical recording and reproduction of sound. In its later forms it is called a gramophone. To recreate the sound, the surface is rotated while a playback stylus traces the groove and is therefore vibrated by it. In later electric phonographs, the motions of the stylus are converted into an electrical signal by a transducer. The phonograph was invented in 1877 by Thomas Edison, while other inventors had produced devices that could record sounds, Edisons phonograph was the first to be able to reproduce the recorded sound. His phonograph originally recorded sound onto a sheet wrapped around a rotating cylinder. A stylus responding to sound vibrations produced an up and down or hill-and-dale groove in the foil, in the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center. Later improvements through the years included modifications to the turntable and its system, the stylus or needle. The disc phonograph record was the dominant audio recording format throughout most of the 20th century, from the mid-1980s on, phonograph use on a standard record player declined sharply because of the rise of the cassette tape, compact disc and other digital recording formats. Records are still a favorite format for some audiophiles and DJs, vinyl records are still used by some DJs and musicians in their concert performances. Musicians continue to release their recordings on vinyl records, the original recordings of musicians are sometimes re-issued on vinyl. Usage of terminology is not uniform across the English-speaking world, in more modern usage, the playback device is often called a turntable, record player, or record changer. When used in conjunction with a mixer as part of a DJ setup, the term phonograph was derived from the Greek words φωνή and γραφή. The similar related terms gramophone and graphophone have similar root meanings, the roots were already familiar from existing 19th-century words such as photograph, telegraph, and telephone. In British English, gramophone may refer to any sound-reproducing machine using disc records, the term phonograph was usually restricted to machines that used cylinder records. Gramophone generally referred to a wind-up machine, after the introduction of the softer vinyl records, 33 1⁄3-rpm LPs and 45-rpm single or two-song records, and EPs, the common name became record player or turntable. Often the home record player was part of a system that included a radio and, later, from about 1960, such a system began to be described as a hi-fi or a stereo. In American English, phonograph, properly specific to machines made by Edison, was used in a generic sense as early as the 1890s to include cylinder-playing machines made by others
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Thomas Edison
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Thomas Alva Edison was an American inventor and businessman, who has been described as Americas greatest inventor. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb. Edison was an inventor, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France. Edisons inventions contributed to mass communication and, in particular, telecommunications and these included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures. His advanced work in these fields was an outgrowth of his career as a telegraph operator. Edison developed a system of generation and distribution to homes, businesses. His first power station was on Pearl Street in Manhattan, New York, Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. and Nancy Matthews Elliott. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in southwestern Ontario, in a known as Shewsbury, later Vienna. Samuel Jr. eventually fled Ontario because he took part in the unsuccessful Mackenzie Rebellion of 1837 and his father, Samuel Sr. had earlier fought in the War of 1812 as captain of the First Middlesex Regiment. By contrast, Samuel Jr. s struggle found him on the losing side, once across the border, he found his way to Milan, Ohio. His patrilineal family line was Dutch by way of New Jersey and his mother taught him at home. Much of his education came from reading R. G, parkers School of Natural Philosophy and The Cooper Union for the Advancement of Science and Art. Edison developed hearing problems at an early age, the cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. In his later years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, Edisons family moved to Port Huron, Michigan, after the railroad bypassed Milan in 1854 and business declined. Edison sold candy and newspapers on trains running from Port Huron to Detroit and he briefly worked as a telegraph operator in 1863 for the Grand Trunk Railway at Stratford, Ontario railway at age 16. He was held responsible for a near collision and he also studied qualitative analysis and conducted chemical experiments on the train until he left the job. Edison obtained the right to sell newspapers on the road, and, with the aid of four assistants, he set in type and printed the Grand Trunk Herald
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Columbia Records
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Columbia Records is an American record label owned by Sony Music Entertainment, a subsidiary of Sony Corporation of America, Inc. the United States division of Sony Corporation. It was founded in 1887, evolving from an enterprise named the American Graphophone Company. Columbia is the oldest surviving brand name in the sound business. Columbia Records went on to release records by an array of singers, instrumentalists. It is one of Sony Musics three flagship record labels alongside RCA Records and Epic Records, rather, as above, it was connected to CBS, a broadcasting media company which had purchased the company in 1938, and had been co-founded in 1927 by Columbia Records itself. Though Arista Records was sold to Bertelsmann Music Group, it would become a sister label of Columbia Records through its mutual connection to Sony Music. The Columbia Phonograph Company was founded in 1887 by stenographer, lawyer and New Jersey native Edward Easton and it derived its name from the District of Columbia, where it was headquartered. At first it had a monopoly on sales and service of Edison phonographs and phonograph cylinders in Washington. As was the custom of some of the regional companies, Columbia produced many commercial cylinder recordings of its own. Columbias ties to Edison and the North American Phonograph Company were severed in 1894 with the North American Phonograph Companys breakup, thereafter it sold only records and phonographs of its own manufacture. In 1902, Columbia introduced the XP record, a brown wax record. According to Gracyk, the molded brown waxes may have sold to Sears for distribution. Columbia began selling records and phonographs in addition to the cylinder system in 1901, preceded only by their Toy Graphophone of 1899. For a decade, Columbia competed with both the Edison Phonograph Company cylinders and the Victor Talking Machine Company disc records as one of the top three names in American recorded sound. In order to add prestige to its catalog of artists. The firm also introduced the internal-horn Grafonola to compete with the extremely popular Victrola sold by the rival Victor Talking Machine Company, during this era, Columbia used the famous Magic Notes logo—a pair of sixteenth notes in a circle—both in the United States and overseas. Columbia was split into two companies, one to make records and one to make players, Columbia Phonograph was moved to Connecticut, and Ed Easton went with it. Eventually it was renamed the Dictaphone Corporation, in late 1923, Columbia went into receivership
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Newark, New Jersey
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Newark is the most populous city in the U. S. state of New Jersey and the seat of Essex County. For 2015, the Census Bureaus Population Estimates Program calculated a population of 281,944, Newark is the second largest city in the New York metropolitan area, located approximately 8 miles west of lower Manhattan. Settled in 1666 by Puritans from New Haven Colony, Newark is one of the oldest European cities in the United States and its location at the mouth of the Passaic River, has made the citys waterfront an integral part of the Port of New York and New Jersey. Today, Port Newark-Elizabeth is the container shipping terminal of the busiest seaport on the American East Coast. In addition, Newark Liberty International Airport was the first municipal airport in the United States. Several leading companies have their headquarters in Newark, including Prudential, PSEG, Panasonic Corporation of North America, Audible. com, IDT Corporation, the U. S. District Court for the District of New Jersey sits in the city as well. Local cultural venues include the New Jersey Performing Arts Center, Newark Symphony Hall, The Prudential Center and the Newark Museum. Newark is divided into five wards, the East, West, South, North and Central wards. Newarks Branch Brook Park is the oldest county park in the United States and is home to the nations largest collection of cherry blossom trees, Newark was settled in 1666 by Connecticut Puritans led by Robert Treat from the New Haven Colony. It was conceived as an assembly of the faithful, though this did not last for long as new settlers came with different ideas. On October 31,1693 it was organized as a New Jersey township based on the Newark Tract, Newark was granted a Royal charter on April 27,1713. It was incorporated on February 21,1798 by the New Jersey Legislatures Township Act of 1798, during its time as a township, portions were taken to form Springfield Township, Caldwell Township, Orange Township, Bloomfield Township and Clinton Township. Newark was reincorporated as a city on April 11,1836, replacing Newark Township, the previously independent Vailsburg borough was annexed by Newark on January 1,1905. In 1926, South Orange Township changed its name to Maplewood, as a result of this, a portion of Maplewood known as Ivy Hill was re-annexed to Newarks Vailsburg. During the American Revolutionary War British troops made several raids into the town, the city has experienced revitalization since the 1990s. According to the United States Census Bureau, the city had an area of 26.107 square miles. It has the third-smallest land area among the 100 most populous cities in the U. S. behind neighboring Jersey City and Hialeah, the citys altitude ranges from 0 in the east to approximately 230 feet above sea level in the western section of the city. Newark is essentially a large basin sloping towards the Passaic River, historically, Newarks high places have been its wealthier neighborhoods
