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Winches
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension (physics), tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a Bobbin, spool (or drum) attached to a hand crank (mechanism), crank. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called Capstan_(nautical), capstans. Despite this, sailboat capstans are most often referred to as winches. Winches are the basis of such machines as tow trucks, steam shovels and elevators. More complex designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. It might include a solenoid brake and/or a Mechanical brake stretch wrapper, mechanical brake or ratchet (device), ratchet and pawl which prevents it unwinding unless the pawl is retracted. The rope may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratchet (device)
A ratchet (occasionally spelled rachet) is a mechanical device that allows continuous linear or rotary motion in only one direction while preventing motion in the opposite direction. Ratchets are widely used in machinery and tools. The word ''ratchet'' is also used informally to refer to a ratcheting socket wrench. __TOC__ Theory of operation A ratchet consists of a round gear or a linear rack with teeth, and a pivoting, spring-loaded finger called a '' pawl'' (or ''click'', in clocks and watches) that engages the teeth. The teeth are uniform but are usually asymmetrical, with each tooth having a moderate slope on one edge and a much steeper slope on the other edge. When the teeth are moving in the unrestricted (i.e. forward) direction, the pawl easily slides up and over the gently sloped edges of the teeth, with a spring forcing it (often with an audible 'click') into the depression between the teeth as it passes the tip of each tooth. When the teeth move in the oppo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Journal Of Hellenic Studies
''The Journal of Hellenic Studies'' is an annual peer-reviewed academic journal covering research in Hellenic studies. It also publishes reviews of recent books of importance to Hellenic studies. It was established in 1880 and is published by Cambridge University Press on behalf of the Society for the Promotion of Hellenic Studies. The editor-in-chief is Lin Foxhall (University of Liverpool). According to the ''Journal Citation Reports'', the journal has a 2022 impact factor of 0.1. Editors The following have been editors-in-chief of the journal: * Percy Gardner, 1879–1895 * Ernest Arthur Gardner, 1897–1932 *Roger Brock, 2011–2016 * Douglas Cairns, 2016–2021 References External links * ''Journal of Hellenic Studies'' 1880–present, at HathiTrust HathiTrust Digital Library is a large-scale collaborative repository of digital content from research libraries. Its holdings include content digitized via Google Books and the Internet Archive digitization initiatives, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanics (Aristotle)
''Mechanics'' (; ), also called ''Mechanical Problems'' or ''Questions of Mechanics'', is a text traditionally attributed to Aristotle, but generally regarded as spurious (cf. Pseudo-Aristotle). Thomas Winter has suggested that the author was Archytas, while Michael Coxhead says that it is only possible to conclude that the author was one of the Peripatetics. During the Renaissance, an edition of this work was published by Francesco Maurolico. A Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ... translation was made by Vettor Fausto, dedicated to Giovanni Badoer in 1517. See also * Aristotle's wheel paradox Notes External links * Pseudo-Aristotle, ''Mechanica''- Greek text and English translation * Works by Aristotle Ancient Greek technology {{phi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aristotle
Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, and the arts. As the founder of the Peripatetic school of philosophy in the Lyceum (classical), Lyceum in Athens, he began the wider Aristotelianism, Aristotelian tradition that followed, which set the groundwork for the development of modern science. Little is known about Aristotle's life. He was born in the city of Stagira (ancient city), Stagira in northern Greece during the Classical Greece, Classical period. His father, Nicomachus (father of Aristotle), Nicomachus, died when Aristotle was a child, and he was brought up by a guardian. At around eighteen years old, he joined Plato's Platonic Academy, Academy in Athens and remained there until the age of thirty seven (). Shortly after Plato died, Aristotle left Athens and, at the request ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoist (device)
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute, ASME, and the Occupational Safety and Health Administration. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products. Types The word "hoist" is used to describe many different types of equipment that lift and lower loads. For example, many people use “hoist” to describe an elevator. The information contained here pertains specially to overhead, con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assyria
Assyria (Neo-Assyrian cuneiform: , ''māt Aššur'') was a major ancient Mesopotamian civilization that existed as a city-state from the 21st century BC to the 14th century BC and eventually expanded into an empire from the 14th century BC to the 7th century BC. Spanning from the early Bronze Age to the late Iron Age, modern historians typically divide ancient Assyrian history into the Early Assyrian period, Early Assyrian ( 2600–2025 BC), Old Assyrian period, Old Assyrian ( 2025–1364 BC), Middle Assyrian Empire, Middle Assyrian ( 1363–912 BC), Neo-Assyrian Empire, Neo-Assyrian (911–609 BC), and Post-imperial Assyria, post-imperial (609 BC– AD 240) periods, based on political events and gradual changes in language. Assur, the first Assyrian capital, was founded 2600 BC, but there is no evidence that the city was independent until the collapse of the Third Dynasty of Ur, in the 21st century BC, when a line of independent kings starting with Puzur-Ashur I began rulin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellespont
The Dardanelles ( ; ; ), also known as the Strait of Gallipoli (after the Gallipoli peninsula) and in classical antiquity as the Hellespont ( ; ), is a narrow, natural strait and internationally significant waterway in northwestern Turkey that forms part of the continental boundary between Asia and Europe and separates Asian Turkey from European Turkey. Together with the Bosporus, the Dardanelles forms the Turkish Straits. One of the world's narrowest straits used for international navigation, the Dardanelles connects the Sea of Marmara with the Aegean and Mediterranean seas while also allowing passage to the Black Sea by extension via the Bosporus. The Dardanelles is long and wide. It has an average depth of with a maximum depth of at its narrowest point abreast the city of Çanakkale. The first fixed crossing across the Dardanelles opened in 2022 with the completion of the 1915 Çanakkale Bridge. Most of the northern shores of the strait along the Gallipoli peni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pontoon Bridge
A pontoon bridge (or ponton bridge), also known as a floating bridge, is a bridge that uses float (nautical), floats or shallow-draft (hull), draft boats to support a continuous deck for pedestrian and vehicle travel. The buoyancy of the supports limits the maximum load that they can carry. Most pontoon bridges are temporary and used in wartime and civil emergencies. There are permanent pontoon bridges in civilian use that can carry highway traffic; generally, the relatively high potential for collapse and sinking (e.g. due to waves and collisions) and high continuous maintenance costs makes pontoons unattractive for most civilian construction. Permanent floating bridges are useful for sheltered water crossings if it is not considered economically feasible to suspend a bridge from anchored Pier (architecture), piers (such as in deep water). Such bridges can require a section that is elevated or can be raised or removed to allow waterborne traffic to pass. Notable permanent pontoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histories (Herodotus)
The ''Histories'' (, ''Historíai''; also known as ''The History'') of Herodotus is considered the founding work of history in Western literature. Although not a fully impartial record, it remains one of the West's most important sources regarding these affairs. Moreover, it established the genre and study of history in the Western world (despite the existence of historical records and chronicles beforehand). ''The'' ''Histories'' also stands as one of the earliest accounts of the rise of the Achaemenid Empire, Persian Empire, as well as the events and causes of the Greco-Persian Wars between the Persian Empire and the Polis, Greek city-states in the 5th century BC. Herodotus portrays the conflict as one between the forces of slavery (the Persians) on the one hand, and freedom (the Athenians and the confederacy of Greek city-states which united against the invaders) on the other. ''The Histories'' was at some point divided into the nine scroll, books that appear in modern editions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greco–Persian Wars
The Greco-Persian Wars (also often called the Persian Wars) were a series of conflicts between the Achaemenid Empire and Greek city-states that started in 499 BC and lasted until 449 BC. The collision between the fractious political world of the Greeks and the enormous empire of the Persians began when Cyrus the Great conquered the Greek-inhabited region of Ionia in 547 BC. Struggling to control the independent-minded cities of Ionia, the Persians appointed tyrants to rule each of them. This would prove to be the source of much trouble for the Greeks and Persians alike. In 499 BC, the tyrant of Miletus, Aristagoras, embarked on an expedition to conquer the island of Naxos, with Persian support; however, the expedition was a debacle and, preempting his dismissal, Aristagoras incited all of Hellenic Asia Minor into rebellion against the Persians. This was the beginning of the Ionian Revolt, which would last until 493 BC, progressively drawing more regions of Asia Minor into the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herodotus Of Halicarnassus
Herodotus (; BC) was a Greek historian and geographer from the Greek city of Halicarnassus (now Bodrum, Turkey), under Persian control in the 5th century BC, and a later citizen of Thurii in modern Calabria, Italy. He wrote the '' Histories'', a detailed account of the Greco-Persian Wars, among other subjects such as the rise of the Achaemenid dynasty of Cyrus. He has been described as " The Father of History", a title conferred on him by the ancient Roman orator Cicero, and the " Father of Lies" by others. The ''Histories'' primarily cover the lives of prominent kings and famous battles such as Marathon, Thermopylae, Artemisium, Salamis, Plataea, and Mycale. His work deviates from the main topics to provide a cultural, ethnographical, geographical, and historiographical background that forms an essential part of the narrative and provides readers with a wellspring of additional information. Herodotus was criticized in his times for his inclusion of "legends and fanci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
