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Helical Fracture Pattern
Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thr ..., a mechanical thread repairing insert * H-el-ical//, stage name for Hikaru, Japanese singer {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helix
A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word ''helix'' comes from the Greek word ''ἕλιξ'', "twisted, curved". A "filled-in" helix – for example, a "spiral" (helical) ramp – is a surface called ''helicoid''. Properties and types The ''pitch'' of a helix is the height of one complete helix turn, measured parallel to the axis of the helix. A double helix consists of two (typically congruent) helices with the same axis, differing by a translation along the axis. A circular helix (i.e. one with constant radius) has constant band curvature and constant torsion. A ''conic helix'', also known as a ''conic spiral'', may be defined as a spiral on a conic surface, with the distance to the apex an expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helical Engine
The Helical engine is a proposed spacecraft propulsion drive that, like other reactionless drives, would violate the laws of physics. The concept was proposed by David M. Burns, formerly a NASA engineer at the Marshall Space Flight Center in Alabama, in a non-peer-reviewed report published on a NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ... server in 2019 describing it as ''"A new concept for in-space propulsion is proposed in which propellant is not ejected from the engine, but instead is captured to create a nearly infinite specific impulse".'' The Helical engine accelerates ions that are confined in a locked loop. Once they are accelerated, the system changes the velocity of the ions in order to change their momentum. Afterward, Burns hypothesized that the engine, by mov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helical Spring
A selection of conical coil springs The most common type of spring is the coil spring, which is made out of a long piece of metal that is wound around itself. Coil springs were in use in Roman times, evidence of this can be found in bronze Fibulae - the clasps worn by Roman soldiers among others. These are quite commonly found in Roman archeological digs. Coil springs can be either compression springs, tension springs or torsion springs, depending on how they are wound. A coil spring is a mechanical device which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded. They are commonly used in mattresses, automotive suspensions, and residential plumbing. Coil springs come in a variety of sizes and shapes and can be used for a variety of applications. Small coil springs are often us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helical Plc
Helical plc (formerly Helical Bar plc) is a property investment and development company. Helical is based in London and a constituent of the FTSE SmallCap Index The FTSE SmallCap Index is an index of small market capitalisation companies consisting of the 351st to the 619th largest-listed companies on the London Stock Exchange main market. The index, which is maintained by FTSE Russell, a subsidiary of .... History The Helical Bar and Engineering Company Limited was incorporated as a limited company on 3 July 1919. The company sold its steel reinforcement business in 1986. In 2016 the company name was changed to Helical plc. Operations The Group is active in London and Manchester and owned a portfolio with total value of £1,108 million as at 31 March 2022. References External links Official site {{Authority control Property companies based in London Real estate companies established in 1919 Companies listed on the London Stock Exchange 1919 establishments in England ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicoil
A threaded insert, also known as a threaded bushing, is a fastener element that is inserted into an object to add a threaded hole. They may be used to repair a stripped threaded hole, provide a durable threaded hole in a soft material, place a thread on a material too thin to accept it, mold or cast threads into a work piece thereby eliminating a machining operation, or simplify changeover from unified to metric threads or vice versa. Types Thread inserts come in many varieties, depending on the application. Threaded inserts for plastics are used in plastic materials and applied with thermal insertion or ultrasonic welding machines. Manufacturers of ready-to-assemble furniture often ship the parts with threaded inserts and other kinds of knock-down fasteners pre-installed. People who use sheet metal or sandwich panel or honeycomb sandwich-structured composite often install threaded inserts to spread shear, tension, and torque loads over a larger area of the material. Captive n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
