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Suction Cup
A suction cup, also known as a sucker, is a device or object that uses the negative Pressure#Fluid pressure, fluid pressure of air or water to adhere to Porosity, nonporous surfaces, creating a Vacuum, partial vacuum. Suction cups occur in nature on the bodies of some animals such as octopuses and squid, and have been reproduced artificially for numerous purposes. Theory The working face of the suction cup is made of elastic, flexible material and has a curved surface. When the center of the suction cup is pressed against a flat, non-Porous medium, porous surface, the volume of the space between the suction cup and the flat surface is reduced, which causes the air or water between the cup and the surface to be expelled past the rim of the circular cup. The cavity which develops between the cup and the flat surface has little to no air or water in it because most of the fluid has already been forced out of the inside of the cup, causing a lack of pressure. The pressure differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suction Cup 1
Suction is the day-to-day term for the movement of gases or liquids along a pressure gradient with the implication that the movement occurs because the lower pressure pulls the gas or liquid. However, the forces acting in this case do not originate from just the lower pressure side, but also from the side of the higher pressure, as a reaction to the pressure difference. When the pressure in one part of a physical system is reduced relative to another, the fluid or gas in the higher pressure region will exert a force relative to the region of lowered pressure, referred to as pressure-gradient force. If all gas or fluid is removed the result is a perfect vacuum in which the pressure is zero. Hence, no negative pressure forces can be generated. Accordingly, from a physics point of view, the objects are not pulled but pushed. Examples Pressure reduction may be Static pressure, static, as in a piston and cylinder arrangement, or Dynamic pressure, dynamic, as in the case of a vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Pressure
In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal gas mixture is the sum of the partial pressures of the gases in the mixture (Dalton's Law). In respiratory physiology, the partial pressure of a dissolved gas in liquid (such as oxygen in arterial blood) is also defined as the partial pressure of that gas as it would be undissolved in gas phase yet in equilibrium with the liquid. This concept is also known as blood gas tension. In this sense, the diffusion of a gas liquid is said to be driven by differences in partial pressure (not concentration). In chemistry and thermodynamics, this concept is generalized to non-ideal gases and instead called fugacity. The partial pressure of a gas is a measure of its Thermodynamic activity, thermodynamic activity. Gases dissolve, diffuse, and react accor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service has over 5,500 journalists working across its output including in 50 foreign news bureaus where more than 250 foreign correspondents are stationed. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buildering
Buildering (also known as edificeering, urban climbing, structuring, skywalking, boulding, or stegophily) describes the act of climbing on the outside of buildings and other artificial structures. If done without ropes or protection far off the ground, buildering is extremely dangerous. It is often practiced outside legal bounds, and is thus practiced mostly at night. Night climbing is a particular branch of buildering which has been practiced for many years in a variety of locations, especially at the Universities of Oxford and Cambridge, England. Night climbing, as distinct from buildering, is performed mainly by undergraduates under cover of darkness. The term "night climbing" has replaced the older term "roof climbing". The philosophy behind night climbing has undergone great change during the 21st century, with urban disciplines such as parkour having a heavy influence on the evolution of night climbing techniques and movements. Adepts of buildering who are seen climbing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plunger
A plunger is a device driven by or against fluid pressure. In plumbing, the term plunger commonly refers to handheld tools used to clear blockages in drains and pipes. Plumbing plungers consist of a rubber suction cup attached to a stick (''shaft'') usually made of wood or plastic. A different bellows-like design is usually constructed of plastic. Alternate names for plumbing plungers include ''force cup'', ''plumber's friend'' or ''plumber's helper''. In musical performance, tools called plungers are used to mute trumpets and trombones. A plunger may also refer to a component of a device that generates fluid flow, such as in a medical syringe or a French press coffee brewer. History The plumbing plunger was invented in 1874 by New York confectioner John Hawley, with the flattened rim added in 1876. The invention is referred to in the patent as a "vent-clearer", and was marketed as a "force cup". Applications Plumbing Use For the common plunger, the cup is pus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerf
Nerf is a toy brand formed by Parker Brothers and currently owned by Hasbro. Most of the toys are a variety of Foam weapon, foam-based weaponry, with other Nerf products including balls for sports such as American football, basketball, and baseball. Their best known toys are their dart guns (referred to by Hasbro as "blasters") that shoot ammunition made from "Nerf foam" (partially reticulated foam, reticulated polyether type polyurethane foam). Their primary slogan, introduced in the 1990s, is ''"It's Nerf or Nothin'!"''. Annual revenues under the Nerf brand are approximately . History Parker Brothers originally developed Nerf, beginning with a polyurethane foam ball. In 1969, Reyn Guyer, a Minnesota-based games inventor, and Minnesota Vikings kicker Fred Cox came to the company with a football game that was safe for indoor play, and after studying it carefully, Parker Brothers decided to eliminate everything but the foam ball. The inventors' in-house name for the bal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raised Floor
A raised floor (also raised flooring, access floor(ing), or raised-access computer floor) provides an elevated structural floor above a solid substrate (often a concrete slab) to create a hidden void for the passage of mechanical and electrical services. Raised floors are widely used in modern office buildings, and in specialized areas such as command centers, Information technology data centers and computer rooms, where there is a requirement to route mechanical services and cables, wiring, and electrical supply. Such flooring can be installed at varying heights from to heights above to suit services that may be accommodated beneath. Additional structural support and lighting are often provided when a floor is raised enough for a person to crawl or even walk beneath. In the U.S., underfloor air distribution is becoming a more common way to cool a building by using the void below the raised floor as a plenum chamber to distribute conditioned air, which has been done in E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a Tumbler (glass), "glass" for drinking, "glasses" for vision correction, and a "magnifying glass". Glass is most often formed by rapid cooling (quenching) of the Melting, molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes. Due to its ease of formability int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mooring (watercraft)
A mooring is any permanent structure to which a seaborne vessel (such as a boat, ship, or amphibious aircraft) may be secured. Examples include quays, wharfs, Jetty, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An ''anchor mooring'' fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, ''mooring'' refers to the act of attaching a vessel to a mooring. The term likely stems from the Dutch language, Dutch verb ''meren'' (to ''moor''), used in English since the end of the 15th century. Permanent anchor mooring These moorings are used instead of temporary anchors because they have considerably more holding power. They cause lesser damage to the marine environment, and are convenient. Where there is a row of moorings they are termed a tier. They are also occasionally used to hold floating docks in place. There are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Plate
Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, daguerreotypes, and photogravure. Glass plates, thinner than standard window glass, became widely used in the late 19th century for their clarity and reliability. Although largely replaced by film during the 20th century, plates continued to be used for specialised scientific and medical purposes until the late 20th century. History Glass plates were far superior to film for research-quality imaging because they were stable and less likely to bend or distort, especially in large-format frames for wide-field imaging. Early plates used the wet collodion process. The wet plate process was replaced late in the 19th century by gelatin dry plates. A view camera nicknamed "The Mammoth" weighing was built by George R. Lawrence in 1899, sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocrates
Hippocrates of Kos (; ; ), also known as Hippocrates II, was a Greek physician and philosopher of the Classical Greece, classical period who is considered one of the most outstanding figures in the history of medicine. He is traditionally referred to as the "Father of Medicine" in recognition of his lasting contributions to the field, such as the use of prognosis and clinical observation, the systematic categorization of diseases, and the (however misguided) formulation of Humorism, humoral theory. His studies set out the basic ideas of modern-day specialties, including surgery, urology, neurology, acute medicine and Orthopedic surgery, orthopedics. The Hippocratic school of medicine revolutionized ancient Greek medicine, establishing it as a discipline distinct from other fields with which it had traditionally been associated (theurgy and philosophy), thus establishing medicine as a profession. However, the achievements of the writers of the Hippocratic Corpus, the practitioners ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gourd
Gourds include the fruits of some flowering plant species in the family Cucurbitaceae, particularly '' Cucurbita'' and '' Lagenaria''. The term refers to a number of species and subspecies, many with hard shells, and some without. Many gourds have large, bulbous bodies and long necks, such as Dipper Gourds, many variations of Bottle Gourd and caveman club gourds. One of the earliest domesticated types of plants, subspecies of the bottle gourd, '' Lagenaria siceraria'', have been discovered in archaeological sites dating from as early as 13,000 BC. Gourds have had numerous uses throughout history, including as tools, musical instruments, objects of art, film, and food. Terminology ''Gourd'' is occasionally used to describe crop plants in the family Cucurbitaceae, like pumpkins, cucumbers, squash, luffa, and melons. More specifically, ''gourd'' refers to the fruits of plants in the two Cucurbitaceae genera '' Lagenaria'' and '' Cucurbita'', or also to their hollow, dried-ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
