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Zig-zag Scan
A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines; it can be described as both jagged and fairly regular. In geometry, this pattern is described as a skew apeirogon. From the point of view of symmetry, a regular zigzag can be generated from a simple motif like a line segment by repeated application of a glide reflection. Although the origin of the word is unclear, its first printed appearances were in French-language books and ephemera of the late 17th century. Examples of zigzags * The trace of a triangle wave or a sawtooth wave is a zigzag. * Pinking shears are designed to cut cloth or paper with a zigzag edge, to lessen fraying. * In sewing, a ''zigzag stitch'' is a machine stitch in a zigzag pattern. * The zigzag arch is an architectural embellishment used in Islamic, Byzantine, Norman and Romanesque architecture. * In seismology, earthquakes recorded in a "zigzag line" form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regular Zig-zag
Regular may refer to: Arts, entertainment, and media Music * "Regular" (Badfinger song) * Regular tunings of stringed instruments, tunings with equal intervals between the paired notes of successive open strings Other uses * Regular character, a main character who appears more frequently and/or prominently than a recurring character * Regular division of the plane, a series of drawings by the Dutch artist M. C. Escher which began in 1936 Language * Regular inflection, the formation of derived forms such as plurals in ways that are typical for the language ** Regular verb * Regular script, the newest of the Chinese script styles Mathematics Algebra and number theory * Regular category, a kind of category that has similarities to both Abelian categories and to the category of sets * Regular chains in computer algebra * Regular element (other), certain kinds of elements of an algebraic structure * Regular extension of fields * Regular ideal (multiple definitions) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawtooth Wave
The sawtooth wave (or saw wave) is a kind of non-sinusoidal waveform. It is so named based on its resemblance to the teeth of a plain-toothed saw with a zero rake angle. A single sawtooth, or an intermittently triggered sawtooth, is called a ramp waveform. The convention is that a sawtooth wave ramps upward and then sharply drops. In a reverse (or inverse) sawtooth wave, the wave ramps downward and then sharply rises. It can also be considered the extreme case of an asymmetric triangle wave. The equivalent piecewise linear functions x(t) = t - \lfloor t \rfloor x(t) = t \bmod 1 based on the floor function of time ''t'' is an example of a sawtooth wave with period 1. A more general form, in the range −1 to 1, and with period ''p'', is 2\left( - \left\lfloor + \right\rfloor\right) This sawtooth function has the same phase as the sine function. While a square wave is constructed from only odd harmonics, a sawtooth wave's sound is harsh and clear and its spectrum cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentine Shape
A serpentine shape is any of certain curved shapes of an object or design, which are suggestive of the shape of a snake (the adjective "serpentine" is derived from the word ''serpent''). Serpentine shapes occur in architecture, in furniture, and in mathematics. In architecture and urban design The serpentine shape is observed in many architectural settings. It may provide strength, as in serpentine walls, it may allow the facade of a building to face in multiple directions, or it may be chosen for purely aesthetic reasons. *At the University of Virginia, serpentine walls (crinkle crankle walls) extend down the length of the main lawn at the University of Virginia and flank both sides of the rotunda. They are one of the many structures Thomas Jefferson created that combine aesthetics with utility. The sinusoidal path of the wall provides strength against toppling over, allowing the wall to be only a single brick thick. *At the Massachusetts Institute of Technology, the List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismograph
A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a ''seismogram''. Such data is used to locate and characterize earthquakes, and to study the internal structure of Earth. Basic principles A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the frame. The mass tends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic waves through planetary bodies. It also includes studies of the environmental effects of earthquakes such as tsunamis; other seismic sources such as volcanoes, plate tectonics, glaciers, rivers, oceanic microseisms, and the atmosphere; and artificial processes such as explosions. Paleoseismology is a related field that uses geology to infer information regarding past earthquakes. A recording of Earth's motion as a function of time, created by a seismograph is called a seismogram. A seismologist is a scientist who works in basic or applied seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romanesque Architecture
Romanesque architecture is an architectural style of medieval Europe that was predominant in the 11th and 12th centuries. The style eventually developed into the Gothic style with the shape of the arches providing a simple distinction: the Romanesque is characterized by semicircular arches, while the Gothic is marked by the pointed arches. The Romanesque emerged nearly simultaneously in multiple countries of Western Europe; its examples can be found across the continent, making it the first pan-European architectural style since Imperial Roman architecture. Similarly to Gothic, the name of the style was transferred onto the contemporary Romanesque art. Combining features of ancient Roman and Byzantine buildings and other local traditions, Romanesque architecture is known by its massive quality, thick walls, round arches, sturdy pillars, barrel vaults, large towers and decorative arcading. Each building has clearly defined forms, frequently of very regular, symmetrical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Architecture
The term Norman architecture is used to categorise styles of Romanesque architecture developed by the Normans in the various lands under their dominion or influence in the 11th and 12th centuries. In particular the term is traditionally used for English Romanesque architecture. The Normans introduced large numbers of castles and fortifications including Norman keeps, and at the same time monastery, monasteries, abbeys, churches and cathedrals, in a style characterised by the usual Romanesque rounded arches (particularly over windows and doorways) and especially massive proportions compared to other regional variations of the style. Origins These Romanesque architecture, Romanesque styles originated in Normandy and became widespread in northwestern Europe, particularly in England, which contributed considerable development and where the largest number of examples survived. At about the same time, Hauteville family, a Norman dynasty that ruled in Sicily produced a distinctive va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byzantine Architecture
Byzantine architecture is the architecture of the Byzantine Empire, or Eastern Roman Empire, usually dated from 330 AD, when Constantine the Great established a new Roman capital in Byzantium, which became Constantinople, until the Fall of Constantinople, fall of the Byzantine Empire in 1453. There was initially no hard line between the Byzantine and Roman Empires, and early Byzantine architecture is stylistically and structurally indistinguishable from late Roman architecture. The style continued to be based on arches, vaults and domes, often on a large scale. Wall mosaics with gold backgrounds became standard for the grandest buildings, with frescos a cheaper alternative. The richest interiors were finished with thin plates of marble or coloured and patterned stone. Some of the columns were also made of marble. Other widely used materials were bricks and stone. Mosaics made of stone or glass tesserae were also elements of interior architecture. Precious wood furniture, like be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Islamic Architecture
Islamic architecture comprises the architectural styles of buildings associated with Islam. It encompasses both Secularity, secular and religious styles from the early history of Islam to the present day. The Muslim world, Islamic world encompasses a wide geographic area historically ranging from western Africa and Europe to eastern Asia. Certain commonalities are shared by Islamic architectural styles across all these regions, but over time different regions developed their own styles according to local materials and techniques, local dynasties and patrons, different regional centers of artistic production, and sometimes Islamic schools and branches, different religious affiliations. Early Islamic architecture was influenced by Roman architecture, Roman, Byzantine architecture, Byzantine, Iranian architecture, Iranian, and Architecture of Mesopotamia, Mesopotamian architecture and all other lands which the early Muslim conquests conquered in the seventh and eighth centuries.: "As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sewing Machine
Diagram of a modern sewing machine Animation of a modern sewing machine as it stitches A sewing machine is a machine used to sew fabric and materials together with thread. Sewing machines were invented during the first Industrial Revolution to decrease the amount of manual sewing work performed in clothing companies. Since the invention of the first sewing machine, generally considered to have been the work of Englishman Thomas Saint in 1790, the sewing machine has greatly improved the efficiency and productivity of the clothing industry. Home sewing machines are designed for one person to sew individual items while using a single stitch type at a time. In a modern sewing machine, the process of stitching has been automated, so that the fabric easily glides in and out of the machine. Early sewing machines were powered by either constantly turning a flywheel handle or with a foot-operated treadle mechanism. Electrically-powered machines were later introduced. Industria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zigzag Stitch
A zigzag stitch is variant geometry of the lockstitch. It is a back-and-forth stitch used where a straight stitch will not suffice, such as in reinforcing buttonholes, in stitching stretchable fabrics, and in temporarily joining two work pieces edge-to-edge. When creating a zigzag stitch, the side to side motion of the sewing machine's needle is controlled by a cam. As the cam rotates, a fingerlike follower, connected to the needle bar, rides along the cam and tracks its indentations. As the follower moves in and out, the needle bar is moved from side to side. Sewing machines made before the mid-1950s mostly lack this hardware and so cannot natively produce a zigzag stitch. However there are often shank-driven attachments available which enable them to achieve a similar effect by moving the fabric from side to side instead of the needle bar. Helen Blanchard is said to have invented and patented the first zigzag stitch sewing machine in 1873. The first dedicated zigzag machine fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinking Shears
Pinking shears are scissors with saw-toothed blades instead of straight blades. They produce a zigzag pattern instead of a straight edge. Before pinking scissors were invented, a pinking punch or pinking iron was used to punch out a decorative hem on a garment. The punch would be hammered by a mallet against a hard surface and the punch would cut through the fabric. In 1874, Eliza P. Welch patented an improved design for a pinking iron, which featured a pair of handles. The pinking shears design that is most well known was patented by Louise Austin in 1893. In 1934, Samuel Briskman patented a pinking shear design (Felix Wyner and Edward Schulz are listed as the inventors). In 1952, Benjamin Luscalzo was granted a patent for pinking shears that would keep the blades aligned to prevent wear. Pinking shears are used for cutting woven cloth. Cloth edges that are unfinished will easily fray, the weave becoming undone and threads pulling out easily. The sawtooth pattern does not pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
