 |
Look up buffer in Wiktionary, the free dictionary. |
Buffer may refer to:
- Buffer state, a country lying between two potentially hostile greater powers, thought to prevent conflict between them
- Buffer zone, any area that keeps two or more other areas distant from one another, may be demilitarized
- Buffer (rail transport), a device that cushions the impact of vehicles against each other
- Buffer stop (bumper in U.S.), a device to prevent railway vehicles from going past the end of a section of track
- Recoil buffer, an accessory for firearms, to cushion the impact of recoil
- Buffer (navy), the colloquial term for the senior seaman sailor in a (British Commonwealth) Navy ship
- Buffer wheel, a wheel attached to a motor similar to a pedestal grinder used to smooth and polish metals and other materials
- Film loop, isolates intermittent motion in a movie projector
People:
- Bruce Buffer, sports announcer
- Michael Buffer, sports announcer
In physical science:
- Buffer solution, a solution which reduces the change of pH upon addition of small amounts of acid or base, or upon dilution
- Buffering agent, the weak acid or weak base in a buffer solution
- Buffer gas, an inert or nonflammable gas
- Buffer (GIS), a zone around a map feature
- Lysis buffer, in biochemistry, a destructor of cell membranes that enables analysis of the compounds within
- Mineral redox buffer, a mineral assemblage which stabilises oxidation state in natural rock systems
In electronics and computer science:
- Data buffer, memory used temporarily to store output or input data
- Framebuffer, a particular type of data buffer for use in graphical display
- Optical buffer, a device that stores optically transmitted data without converting it to the electrical domain
- Buffer amplifier (also sometimes simply called a buffer), an isolating circuit used in electronics or telecommunications
- Buffer (optical fiber), a component used to encapsulate one or more optical fibers in a fiber optic communication cable
 |
This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article. |
https://wn.com/Buffer
Buffer (rail transport)
A buffer is a part of the buffers-and-chain coupling system used on the railway systems of many countries, among them most of those in Europe, for attaching railway vehicles to one another.
Fitted at the ends of the vehicle frames, one at each corner, the buffers are projecting, shock-absorbing pads which, when vehicles are coupled, are brought into contact with those on the next vehicle. The draw chain used between each pair of vehicles includes a screw which is tightened after coupling to shorten the chain and keep the buffers pressed together. Such is known as a 'screw coupling'. Historically, coupling chains were no more than that, a short length of heavy chain (typically three links long) with no adjustment. These would result in a 'loose-coupled train' in which the buffers of adjacent vehicles would only touch when the coupling chain was fully slack, such as when being pushed or going down hill.
Although the buffers in the very earliest days of railways were rigid (dumb buffers), they soon came to be spring-loaded, while those fitted to modern locomotives and rolling stock incorporate oleo-pneumatic shock absorbers.
Buffer solution
A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small or moderate amount of strong acid or base is added to it and thus it is used to prevent changes in the pH of a solution. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. Many life forms thrive only in a relatively small pH range so they utilize a buffer solution to maintain a constant pH. In nature, the bicarbonate buffering system is used to regulate the pH of blood.
Principles of buffering
Buffer solutions achieve their resistance to pH change because of the presence of an equilibrium between the acid HA and its conjugate base A−.
When some strong acid is added to an equilibrium mixture of the weak acid and its conjugate base, the equilibrium is shifted to the left, in accordance with Le Chatelier's principle. Because of this, the hydrogen ion concentration increases by less than the amount expected for the quantity of strong acid added. Similarly, if strong alkali is added to the mixture the hydrogen ion concentration decreases by less than the amount expected for the quantity of alkali added. The effect is illustrated by the simulated titration of a weak acid with pKa = 4.7. The relative concentration of undissociated acid is shown in blue and of its conjugate base in red. The pH changes relatively slowly in the buffer region, pH = pKa ± 1, centered at pH = 4.7 where [HA] = [A−]. The hydrogen ion concentration decreases by less than the amount expected because most of the added hydroxide ion is consumed in the reaction
Ches
Ches may refer to:
Workshop on Cryptographic Hardware and Embedded Systems
Workshop on Cryptographic Hardware and Embedded Systems (CHES) is a workshop for cryptography research, focusing on the implementation of cryptographic algorithm. The two general areas treated are the efficient and the secure implementation of algorithms. Related topics such as random number generators, physical unclonable function or special-purpose cryptanalytical machines are also commonly covered at the workshop. CHES is sponsored by the International Association for Cryptologic Research. It was first held in Worcester, Massachusetts in 1999 at Worcester Polytechnic Institute (WPI). It was founded by Çetin Kaya Koç and Christof Paar. CHES 2000 was also held at WPI; after that, the conference has been held at various locations worldwide, including in chronological order Paris, San Francisco, Cologne, Boston, Edinburgh, Yokohama, Vienna, Washington, D.C., Lausanne, Santa Barbara, Nara, Leuven, and again Santa Barbara. In the last few years, CHES had between 300-400 participants, making it one of the largest events in the academic cryptography community.
