|
Spoke Type Rotors
A spoke is one of some number of rods radiating from the center of a wheel (the Bicycle hub, hub where the axle connects), connecting the hub with the round traction surface. The term originally referred to portions of a log that had been riving, riven (split lengthwise) into four or six sections. The radial members of a wagon wheel were made by carving a spoke (from a log) into their finished shape. A spokeshave is a tool originally developed for this purpose. Eventually, the term spoke was more commonly applied to the finished product of the wheelwright's work than to the materials they used. History The spoked wheel was invented to allow the construction of lighter and swifter vehicles. The earliest physical evidence for spoked wheels was found in the Sintashta culture, dating to 2000 BCE. Soon after this, horse cultures of the Caucasus region used horse-drawn spoked-wheel war chariots for the greater part of three centuries. They moved deep into the Greek peninsula, whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheel
A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a ship's wheel, steering wheel, potter's wheel, and flywheel. Common examples can be found in transport applications. A wheel reduces friction by facilitating motion by rolling together with the use of axles. In order for a wheel to rotate, a Moment (physics), moment must be applied to the wheel about its axis, either by gravity or by the application of another external force or torque. Terminology The English word '':wikt:wheel, wheel'' comes from the Old English word , from Proto-Germanic language, Proto-Germanic , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minoan Civilization
The Minoan civilization was a Bronze Age culture which was centered on the island of Crete. Known for its monumental architecture and energetic art, it is often regarded as the first civilization in Europe. The ruins of the Minoan palaces at Knossos and Phaistos are popular tourist attractions. The Minoan civilization developed from the local Neolithic culture around 3100BC, with complex urban settlements beginning around 2000BC. After 1450BC, they came under the cultural and perhaps political domination of the mainland Mycenaean Greeks, forming a hybrid culture which lasted until around 1100BC. Minoan art included elaborately decorated pottery, seals, figurines, and colorful frescoes. Typical subjects include nature and ritual. Minoan art is often described as having a fantastical or ecstatic quality, with figures rendered in a manner suggesting motion. Little is known about the structure of Minoan society. Minoan art contains no unambiguous depiction of a monarch, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Compression
In mechanics, compression is the application of balanced inward ("pushing") forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.Ferdinand Pierre Beer, Elwood Russell Johnston, John T. DeWolf (1992), "Mechanics of Materials". (Book) McGraw-Hill Professional, It is contrasted with tension or traction, the application of balanced outward ("pulling") forces; and with shearing forces, directed so as to displace layers of the material parallel to each other. The compressive strength of materials and structures is an important engineering consideration. In uniaxial compression, the forces are directed along one direction only, so that they act towards decreasing the object's length along that direction. The compressive forces may also be applied in multiple directions; for example inwards along the edges of a plate or all over the side surface of a cylinder, so as to reduce it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tension (mechanics)
Tension is the pulling or stretching force transmitted axially along an object such as a string, rope, chain, rod, truss member, or other object, so as to stretch or pull apart the object. In terms of force, it is the opposite of ''compression''. Tension might also be described as the action-reaction pair of forces acting at each end of an object. At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length. Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitting tension will exert forces on the objects ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tire
A tire (North American English) or tyre (Commonwealth English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, providing a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, designed to match the vehicle's weight and the bearing on the surface that it rolls over by exerting a pressure that will avoid deforming the surface. The materials of modern pneumatic tires are synthetic rubber, natural rubber, fabric, and wire, along with carbon black and other chemical compounds. They consist of a tire tread, tread and a body. The tread provides Traction (engineering), traction while the body provides containment for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Wheel
Wire wheels, wire-spoked wheels, tension-spoked wheels, or "suspension" wheels are wheels whose rims connect to their hubs by wire spokes. Although these wires are considerably stiffer than a similar diameter wire rope, they function mechanically the same as tensioned flexible wires, keeping the rim true while supporting applied loads. The term ''suspension wheel'' should not be confused with vehicle suspension. Wire wheels are used on most bicycles and are still used on many motorcycles. They were invented by aeronautical engineer George Cayley in 1808. Although Cayley first proposed wire wheels, he did not apply for a patent. The first patent for wire wheels was issued to Theodore Jones of London, England on October 11, 1826. Eugène Meyer of Paris, France was the first person to receive, in 1869, a patent for wire wheels on bicycles. Bicycle wheels were not strong enough for cars until the development of tangentially spoked wheels. They rapidly became well establis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celt
The Celts ( , see Names of the Celts#Pronunciation, pronunciation for different usages) or Celtic peoples ( ) were a collection of Indo-European languages, Indo-European peoples. "The Celts, an ancient Indo-European people, reached the apogee of their influence and territorial expansion during the 4th century BC, extending across the length of Europe from Britain to Asia Minor."; . "[T]he Celts, were Indo-Europeans, a fact that explains a certain compatibility between Celtic, Roman, and Germanic mythology."; . "The Celts and Germans were two Indo-European groups whose civilizations had some common characteristics."; . "Celts and Germans were of course derived from the same Indo-European stock."; . "Celt, also spelled Kelt, Latin Celta, plural Celtae, a member of an early Indo-European people who from the 2nd millennium bce to the 1st century bce spread over much of Europe." in Europe and Anatolia, identified by their use of Celtic languages and other cultural similarities.. "C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcolithic
The Chalcolithic ( ) (also called the Copper Age and Eneolithic) was an archaeological period characterized by the increasing use of smelted copper. It followed the Neolithic and preceded the Bronze Age. It occurred at different periods in different areas, but was absent in some parts of the world, such as Russia, where there was no well-defined Copper Age between the Stone and Bronze Ages. Stone tools were still predominantly used during this period. The Chalcolithic covers both the early cold working (hammering) of near pure copper ores, as exhibited by the likes of North American Great Lakes Old Copper complex, from around 6,500 BC, through the later copper smelting cultures. The archaeological site of Belovode, on Rudnik mountain in Serbia, has the world's oldest securely dated evidence of copper smelting at high temperature, from . The transition from Copper Age to Bronze Age in Europe occurred between the late 5th and the late In the Ancient Near East the Copper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fifteenth Dynasty Of Egypt
The Fifteenth Dynasty was a foreign dynasty of ancient Egypt. It was founded by Salitis, a Hyksos from West Asia whose people had invaded the country and conquered Lower Egypt. The 15th, 16th, and 17th Dynasties of ancient Egypt are often combined under the group title, Second Intermediate Period. The 15th Dynasty dates approximately from 1650 to 1550 BC. Dynastic history The kings of the Fifteenth Dynasty are said to have been Canaanite. Pharaoh Kamose is known to have referred to Apophis, one of the kings of the dynasty, as "Chieftain of Retjenu (i.e. Caanan)". The kings of the Fifteenth Dynasty formed "the second Asiatic Kingdom in the Delta", covering an area which may have included Canaan itself, although the archaeological record is sparse. The dynasty probably lasted for a period of about 108 years. The first king, also described as a Hyksos (''ḥḳꜣw-ḫꜣswt'', a "shepherd" according to Africanus), led his people into an occupation of the Nile Delta area and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Egypt
Lower Egypt ( ') is the northernmost region of Egypt, which consists of the fertile Nile Delta between Upper Egypt and the Mediterranean Sea, from El Aiyat, south of modern-day Cairo, and Dahshur. Historically, the Nile River split into seven branches of the delta in Lower Egypt. Lower Egypt was divided into nomes and began to advance as a civilization after 3600 BC. Today, it contains two major channels that flow through the delta of the Nile River – Mahmoudiyah Canal (ancient Agathos Daimon) and Muways Canal (, "waterway of Moses"). Name In Ancient Egyptian, Lower Egypt was known as ''mḥw'' which means "north". Later on, during Antiquity and the Middle Ages, Greeks and Romans called it ''Κάτω Αἴγυπτος'' or ''Aegyptus Inferior'' both meaning "Lower Egypt", but Copts carried on using the old name related to the north – ''Tsakhet'' () or ''Psanemhit'' () meaning the "Northern part". It was further divided into a number of regions or nomes () – '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chariotry In Ancient Egypt
In ancient Egyptian society, primarily during the New Kingdom, chariotry stood as an independent unit in the king’s military force. It is thought that chariots came to Egypt with the Hyksos people as a weapon during the 16th century.Hyskos introduced chariots to ancient Egypt The Egyptians later developed their own chariot design, which when compared to the Hyksos counterpart was lighter. Beyond their role in warfare, chariots seem to have a role in royal power both in and out of Egypt. Design Archaeologist Joost Crouwel writes that "chariots were not sudden inventions but developed out of earlier vehicles that were mounted on disk or cross-bar wheels. This development can best be traced in the Near East, where spoke-wheeled and horse-drawn ‘tr ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
